WO2012115248A1

WO2012115248A1 - Solar cell module and solar generator device

Info

Publication number: WO2012115248A1
Application number: PCT/JP2012/054639
Authority: WO
Inventors: 内田　秀樹; 英臣由井; 時由梅田
Original assignee: シャープ株式会社
Priority date: 2011-02-25
Filing date: 2012-02-24
Publication date: 2012-08-30

Abstract

A solar cell module comprises: a fluorescent light guiding body which includes a fluorescent light body, and which is configured to further comprise a first primary face and a first end face, to absorb by the fluorescent light body a portion of exterior light which has entered via the first primary face, to propagate a first light which is radiated from the fluorescent light body and to discharge same from the first end face; and a first light guiding body, which is configured to further comprise a second primary face, a third primary face further comprising a first oblique face, and a second end face, for a second light among the exterior light which passes through the fluorescent light guiding body without being absorbed by the fluorescent light body to enter via the second primary face, to be reflected and propagated with the first oblique face, and to be emitted from the second end face.

Description

Solar cell module and solar power generation device

The present invention relates to a solar cell module and a solar power generation device.
This application claims priority based on Japanese Patent Application No. 2011-040191 filed in Japan on February 25, 2011, the contents of which are incorporated herein by reference.

As a solar power generation device that installs a solar cell element on the end face of a light guide and makes light propagated through the light guide enter the solar cell element to generate power, the solar power generation device described in Patent Document 1 is Are known. The solar power generation device of Patent Document 1 is a window-type solar power generation device that uses a light guide as a window. In the solar power generation device of Patent Document 1, a part of sunlight incident from one main surface of the light guide is propagated into the light guide and guided to the solar cell element. A phosphor is applied to the surface of the light guide, and the phosphor is excited by sunlight incident on the light guide. Light (fluorescence) emitted from the phosphor propagates through the light guide and enters the solar cell element to generate power.

JP-A-3-273686

In the solar power generation device of Patent Document 1, the sunlight used for exciting the phosphor is very small of the sunlight incident on the light guide. Most of the sunlight incident on the light guide is transmitted through the light guide and does not contribute to power generation. Therefore, a solar power generation device with high power generation efficiency cannot be provided.

An object of the aspect of the present invention is to provide a solar cell module with high power generation efficiency and a solar power generation device using the solar cell module.

The solar cell module according to the aspect of the present invention includes a phosphor, has a first main surface and a first end surface, and absorbs a part of external light incident from the first main surface by the phosphor, A fluorescent light guide configured to propagate the first light emitted from the body and emit the light from the first end surface; a second main surface; a third main surface having a first inclined surface; and a second end surface. Second light that is not absorbed by the phosphor but transmitted through the fluorescent light guide is incident from the second main surface, is reflected by the first inclined surface, and is propagated. A first light guide configured to emit from two end faces;

And a first solar cell element that receives the first light, and a second solar cell element that receives the second light, the spectral sensitivity of the first solar cell element and the second solar cell element. The wavelength characteristics may be different from each other.

The fluorescent light guide may include at least two types of fluorescent materials having different emission spectrum peak wavelengths as the fluorescent material.

The first solar cell element may receive the fluorescence emitted from the phosphor having the largest peak wavelength of the emission spectrum among the at least two kinds of phosphors.

The spectral sensitivity of the first solar cell element at the peak wavelength of the emission spectrum of the phosphor having the largest emission spectrum peak wavelength among the at least two types of phosphors is any of the other ones provided in the fluorescence light guide. It may be larger than the spectral sensitivity of the first solar cell element at the peak wavelength of the emission spectrum of the phosphor.

The fluorescent light guide may include a quantum dot fluorescent material as the fluorescent material.

Furthermore, a first light condensing member that condenses the first light emitted from the first end face of the fluorescent light guide and enters the first solar cell element may be provided.

The first light collecting member may be configured to make the intensity distribution of the first light emitted from the first end face of the fluorescent light guide uniform and emit the same to the first solar cell element.

Furthermore, a second condensing member that condenses the second light emitted from the second end face of the first light guide and enters the second solar cell element may be provided.

The second light collecting member may be configured to uniformize the intensity distribution of the second light emitted from the second end face of the first light guide and emit the same to the second solar cell element.

Furthermore, the solar cell element that receives the first light emitted from the first end surface of the fluorescent light guide and the second light emitted from the second end surface of the first light guide, and the solar cell The first light emitted from the first end surface of the fluorescent light guide and the first light between the element and the first end surface of the fluorescent light guide and between the second end surface of the first light guide. And a condensing member configured to condense the second light emitted from the second end face of the one light guide and make it incident on the solar cell element.

The condensing member equalizes the intensity distribution of the first light emitted from the first end face of the fluorescent light guide and the second light emitted from the second end face of the first light guide, and You may be comprised so that it inject | emits to a solar cell element.

The fluorescent light guide may be formed by dispersing the fluorescent material inside a transparent light guide.

The fluorescent light guide may include a transparent light guide and a phosphor layer provided on the first main surface of the transparent light guide and having the phosphor dispersed therein.

It may further include an adhesive layer for releasably bonding the transparent light guide and the phosphor layer.

The second main surface is the third main surface so that the thickness of the first light guide gradually decreases from the second end surface of the first light guide toward the third end surface facing the second end surface. It may be inclined with respect to the surface.

The fluorescent light guide includes a fourth main surface different from the first main surface, and a fourth end surface opposite to the first end surface, and the first end surface to the fourth end surface of the fluorescent light guide. The first main surface may be inclined with respect to the fourth main surface so that the thickness of the fluorescent light guide gradually decreases toward the surface.

The first end face of the fluorescent light guide and the third end face of the first light guide are arranged in the same direction, and the fourth end face of the fluorescent light guide and the second end face of the first light guide are The fluorescent light guide and the first light guide may be laminated so as to face the same direction.

And a second light guide having a fifth main surface, a sixth main surface, and a fifth end surface, wherein the first light guide is disposed between the fluorescent light guide and the second light guide. And the second light guide causes a part of the second light transmitted through the first light guide to be incident from the fifth main surface and reflected by the second inclined surface provided on the sixth main surface. It may be configured to propagate and emit from the fifth end face.

The angle of the first inclined surface and the angle of the second inclined surface may be different from each other.

Furthermore, a condensing member configured to condense the second light emitted from the second end surface of the first light guide and the fifth end surface of the second light guide so as to enter the solar cell element. You may have.

The condensing member that condenses the second light emitted from the second end surface of the first light guide and the fifth end surface of the second light guide is the second end surface of the first light guide and the second end surface of the first light guide. The intensity distribution of the second light emitted from the fifth end surface of the two light guides may be uniformized and emitted to the solar cell element.

A solar power generation device according to an aspect of the present invention includes the solar cell module.

According to the aspect of the present invention, it is possible to provide a solar cell module with high power generation efficiency and a solar power generation apparatus using the solar cell module.

It is a schematic perspective view of the solar cell module of 1st Embodiment. It is sectional drawing of a solar cell module. It is an enlarged view of sectional drawing of a solar cell module. It is a figure which shows the absorption characteristic of fluorescent substance. It is a figure which shows the absorption characteristic of fluorescent substance. It is a figure which shows the light emission characteristic of fluorescent substance. It is a figure which shows the light emission characteristic of fluorescent substance. It is a figure which shows the energy transfer by photoluminescence. It is explanatory drawing of a Forster mechanism. It is explanatory drawing of a Forster mechanism. It is explanatory drawing of a Forster mechanism. It is a figure which shows the spectral sensitivity curve of the solar cell using a compound semiconductor. It is a spectral sensitivity curve of a solar cell using amorphous silicon. It is a figure which shows the extraction efficiency of 1st light guide body light. It is a figure which shows the taking-out efficiency of 2nd light guide body light. It is a figure which shows the extraction efficiency of light at the time of laminating | stacking a 1st light guide and a 2nd light guide in this order from the incident side of light. It is a figure which shows the extraction efficiency of light at the time of laminating | stacking a 2nd light guide and a 1st light guide in this order from the incident side of light. It is a spectral sensitivity curve of the three-layer junction compound solar cell which laminated InGaP, GaAs, and InGaAs. It is a figure which shows the structure of a 3 layer joining compound solar cell. It is a figure which shows the absorption spectrum and emission spectrum of the quantum dot fluorescent substance used for the solar cell module of 2nd Embodiment. It is a figure which shows the simulation result of the light extraction efficiency of a 1st light guide and a 2nd light guide. It is sectional drawing of the solar cell module of 3rd Embodiment. It is sectional drawing of the solar cell module of 4th Embodiment. It is sectional drawing of the 2nd light guide applied to the solar cell module of 5th Embodiment. It is sectional drawing which shows the other structural example of the 2nd light guide of 5th Embodiment. It is sectional drawing which shows the structure of the principal part of a 2nd light guide. It is sectional drawing of the solar cell module of 6th Embodiment. It is a figure which shows a mode that light propagates the inside of a 1st light guide. It is sectional drawing of the solar cell module of 7th Embodiment. It is sectional drawing which shows the structure of two types of 1st light guides applied to the solar cell module of 8th Embodiment. It is an enlarged view of sectional drawing showing composition of two kinds of 1st light guides applied to a solar cell module of an 8th embodiment. It is sectional drawing which shows the structure of two types of 1st light guides and condensing members applied to the solar cell module of 9th Embodiment. It is a schematic block diagram of a solar power generation device.

[First Embodiment]
FIG. 1 is a schematic perspective view of the solar cell module 1 of the first embodiment.

The solar cell module 1 includes a light guide unit 2, a solar cell element 5, a solar cell element 6, and a frame body 10. The light guide unit 2 is formed by laminating a first light guide (shape light guide) 3 and a second light guide (fluorescent light guide) 4. The solar cell element 5 receives light emitted from the first end surface 3 c of the first light guide 3. The solar cell element 6 receives light emitted from the first end face 4 c of the second light guide 4. The frame body 10 integrally holds the light guide unit 2, the solar cell element 5, and the solar cell element 6.

The first light guide 3 includes a first main surface 3a that is a light incident surface, a second main surface 3b that faces the first main surface 3a, and a first end surface 3c that is a light emission surface. . The second light guide 4 includes a first main surface 4a that is a light incident surface, a second main surface 4b that faces the first main surface 4a, and a first end surface 4c that is a light emission surface. . The first light guide 3 and the second light guide 4 are arranged such that the first main surface 3a of the first light guide 3 and the second main surface 4b of the second light guide 4 are opposed to each other. The light guide 3 and the second light guide 4 are stacked in the Z direction via an air layer K (low refractive index layer) having a smaller refractive index than the light guide 3 and the second light guide 4.

The first main surface 3a of the first light guide 3 and the first main surface 4a of the second light guide 4 face the same direction (light incident side: -Z direction). By laminating the first light guide 3 and the second light guide 4 along the incident direction of the light L, it is captured by the second light guide 4 on the front stage side (side closer to the light L incident side). The light that has not been received can be taken in by the first light guide 3 on the rear stage side (the side far from the light incident side).

The first end surface 3c of the first light guide 3 and the first end surface 4c of the second light guide 4 are oriented in the same direction. The first end surface 3c of the first light guide 3 and the first end surface 4c of the second light guide 4 are arranged on the same plane parallel to the XZ plane. Therefore, the solar cell element 5 that receives the light emitted from the first end surface 3c of the first light guide 3 and the solar cell element 6 that receives the light emitted from the first end surface 4c of the second light guide 4; Can be placed in one place.

The first light guide 3 is a substantially rectangular plate-like member having a first main surface 3a and a second main surface 3b perpendicular to the Z axis (parallel to the XY plane). As the first light guide 3, a highly transparent organic material or inorganic material such as acrylic resin, polycarbonate resin, or glass is used.

The second main surface 3b of the first light guide 3 is provided with a plurality of grooves T extending in the X direction. The groove T is a V-shaped groove having an inclined surface T1 that is inclined with respect to a plane parallel to the XY plane and a surface T2 that intersects the inclined surface T1. In FIG. 1, only a few grooves T are shown in order to simplify the drawing, but in practice, a large number of fine grooves T having a width of about 100 μm are formed. The groove T is formed, for example, by injection molding a resin (for example, polymethyl methacrylate resin: PMMA) using a mold.

The inclined surface T1 is a reflecting surface that totally reflects the light L (for example, sunlight) incident from the first main surface 3a and changes the traveling direction of the light to the direction toward the first end surface 3c. The light L incident at an angle close to perpendicular to the first main surface 3a is reflected by the inclined surface T1 and propagates in the first light guide 3 in the Y direction.

The second main surface 3b of the first light guide 3 is provided with a plurality of such grooves T in the Y direction so that the inclined surfaces T1 and T2 are in contact with each other. The shape and size of the plurality of grooves T provided on the second main surface 3b are all the same.

The second light guide 4 is a substantially rectangular plate-like member having a first main surface 4a and a second main surface 4b perpendicular to the Z axis (parallel to the XY plane). The second light guide 4 is obtained by dispersing a phosphor in a base material made of a highly transparent organic or inorganic material such as acrylic resin, polycarbonate resin, or glass. Examples of the phosphor include a plurality of types of phosphors that absorb ultraviolet light or visible light and emit visible light or infrared light. The light emitted from the phosphor propagates through the second light guide 4 and is emitted from the first end face 4 c, and is used for power generation by the solar cell element 6.

Note that visible light is light in a wavelength region of 380 nm to 750 nm, ultraviolet light is light in a wavelength region less than 380 nm, and infrared light is light in a wavelength region larger than 750 nm.

It is desirable that the material of the light guide constituting the light guide unit has transparency to wavelengths of 400 nm or less so that external light can be taken in effectively. For example, a material having a transmittance of 90% or more, more preferably 93% or more with respect to light in a wavelength region of 360 nm to 800 nm is suitable. For example, in the case of a silicon resin substrate, a quartz substrate, or a PMMA resin substrate, “Acrylite” (registered trademark) manufactured by Mitsubishi Rayon is suitable because it has high transparency to light in a wide wavelength region. .

The first main surface 4a and the second main surface 4b of the second light guide 4 are flat surfaces substantially parallel to the XY plane. On the end face other than the first end face 4c of the second light guide 4, a reflection layer 9 that reflects light (fluorescence) emitted from the phosphor is provided.

The second main surface 3 b of the first light guide 3 is provided with a reflective layer 7 that reflects the light transmitted through the second main surface 3 b of the first light guide 3 to the inside of the first light guide 3. Yes. Although illustration is omitted, light that leaks from the end face to the outside of the first light guide 3 is reflected to the inside of the first light guide 3 on the end face other than the first end face 3 c of the first light guide 3. A reflective layer may be provided.

The solar cell element 5 is disposed with the light receiving surface facing the first end surface 3 c of the first light guide 3. The solar cell element 6 is disposed with the light receiving surface facing the first end surface 4 c of the second light guide 4.

As the solar cell element 5 and the solar cell element 6, known solar cells such as silicon solar cells, compound solar cells, and organic solar cells can be used. Especially, the compound type solar cell using a compound semiconductor is suitable as the solar cell element 5 and the solar cell element 6 since high-efficiency electric power generation is possible.

The frame body 10 includes a transmission surface 10a that transmits light L on a surface facing the first main surface 4a of the second light guide 4 disposed on the most front side. The transmission surface 10a may be an opening of the frame 10, or may be a transparent member such as glass fitted in the opening of the frame 10. The first main surface 4 a of the second light guide 4 that overlaps the transmission surface 10 a of the frame 10 when viewed from the Z direction is the light incident surface of the light guide unit 2. The first end surface 3 c of the first light guide 3 and the first end surface 4 c of the second light guide 4 are the first light exit surfaces of the light guide unit 2.

FIG. 2A is a cross-sectional view of the solar cell module 1. FIG. 2B is a cross-sectional view of the groove T provided in the second main surface 3 b of the first light guide 3.

The second main surface 3b of the first light guide 3 is provided with a plurality of grooves T that reflect the light incident from the first main surface 3a and change the traveling direction of the light toward the first end surface 3c. ing. The groove T is a V-shaped groove in which an inclined surface T1 that forms an angle θ with respect to the Y axis and a surface T2 that is perpendicular to the Y axis intersect at a ridgeline T3. A surface T2 is disposed on the first end surface 3c side with the ridge line T3 interposed therebetween, and an inclined surface T1 is disposed on the opposite side to the first end surface 3c.

For example, the angle θ is 42 °, the width W in the Y direction of one groove T is 100 μm, the depth D in the Z direction of the groove T is 90 μm, and the refractive index of the first light guide 3 is 1.5. However, the angle θ, the width of the groove T in the Y direction, the depth of the groove T in the Z direction, and the refractive index of the first light guide 3 are not limited thereto.

In the second light guide 4, a plurality of types of phosphors having different absorption wavelength ranges (for example, the first phosphor 8a, the second phosphor 8b, and the third phosphor 8c in FIG. 2) are dispersed. . The first phosphor 8a absorbs ultraviolet light and emits blue fluorescence, the second phosphor 8b absorbs blue light and emits green fluorescence, and the third phosphor 8c emits green light. Absorbs and emits red fluorescence. The first phosphor 8a, the second phosphor 8b, and the third phosphor 8c are mixed when, for example, a PMMA resin is molded. The mixing ratio of the first phosphor 8a, the second phosphor 8b, and the third phosphor 8c is as follows. The mixing ratio of the first phosphor 8a, the second phosphor 8b, and the third phosphor 8c is shown as a volume ratio with respect to the PMMA resin.

As the first phosphor 8a, Lumogen F Blue (trade name) manufactured by BASF is used, and the mixing ratio is 0.02%. Lumogen F Green (trade name) manufactured by BASF is used as the second phosphor 8b, and the mixing ratio is 0.02%. As the third phosphor 8c, BASF Lumogen F Red (trade name) is used, and the mixing ratio is 0.02%.

3 to 6 are diagrams showing the emission characteristics and absorption characteristics of the first phosphor 8a, the second phosphor 8b, and the third phosphor 8c. In FIG. 3, the white squares indicate the spectrum of sunlight after the ultraviolet light is absorbed by the first phosphor 8a. The triangle indicates the spectrum of sunlight after the blue light is absorbed by the second phosphor 8b. The cross mark indicates the spectrum of sunlight after the green light is absorbed by the third phosphor 8c. A black square shows the spectrum of sunlight. In FIG. 4, circles indicate the spectrum of sunlight after ultraviolet light, blue light, and green light are absorbed by the first phosphor 8a, the second phosphor 8b, and the third phosphor 8c. A square shows the spectrum of sunlight. In FIG. 5, the black square is an emission spectrum of the first phosphor 8a. The triangle is the emission spectrum of the second phosphor 8b. A white square is an emission spectrum of the third phosphor 8c. FIG. 6 shows a spectrum of light emitted from the first end face of the second light guide including the first phosphor 8a, the second phosphor 8b, and the third phosphor 8c.

As shown in FIGS. 3 and 4, the first phosphor 8a absorbs light having a wavelength of approximately 420 nm or less. The second phosphor 8b absorbs light having a wavelength of approximately 420 nm or more and 520 nm or less. The third phosphor 8c absorbs light having a wavelength of approximately 520 nm or more and 620 nm or less. The first phosphor 8a, the second phosphor 8b, and the third phosphor 8c absorb almost all light having a wavelength of 620 nm or less in the sunlight incident on the second light guide. In the sunlight spectrum, the proportion of light having a wavelength of 620 nm or less is about 48%. Therefore, 48% of the light incident on the light incident surface of the light guide unit (the first main surface of the second light guide) is the first phosphor 8a and the second phosphor 8b included in the second light guide. And the remaining 52% is transmitted through the second light guide and incident on the first light guide.

As shown in FIG. 5, the emission spectrum of the first phosphor 8a has a peak wavelength at 430 nm. The emission spectrum of the second phosphor 8b has a peak wavelength at 520 nm. The emission spectrum of the third phosphor 8c has a peak wavelength at 630 nm. However, as shown in FIG. 6, the spectrum of light emitted from the first end face of the second light guide including the first phosphor 8a, the second phosphor 8b, and the third phosphor 8c is the third phosphor. It has a peak wavelength only at a wavelength corresponding to the peak wavelength (630 nm) of the emission spectrum of 8c, the peak wavelength (430 nm) of the emission spectrum of the first phosphor 8a and the peak wavelength (520 nm of the emission spectrum of the second phosphor 8b). ) Does not have a peak wavelength.

The cause of the disappearance of the peak of the emission spectrum corresponding to the first phosphor 8a and the peak of the emission spectrum corresponding to the second phosphor 8b is the energy transfer between the phosphors due to photoluminescence (PL) and the Forster mechanism. Examples thereof include energy transfer between phosphors by (fluorescence resonance energy transfer). Energy transfer by photoluminescence occurs when fluorescence emitted from one phosphor is used as excitation energy for another phosphor. In the Förster mechanism, excitation energy directly moves between two adjacent phosphors by electron resonance without going through such light emission and absorption processes. Energy transfer between the phosphors by the Förster mechanism is performed without going through the process of light emission and absorption, so that energy loss is small. Therefore, it contributes to the improvement of the power generation efficiency of the solar cell module.

Here, the Förster mechanism will be described with reference to FIGS. 7A to 8B. FIG. 7A is a diagram illustrating energy transfer by photoluminescence, and FIGS. 8A and 8B are diagrams illustrating energy transfer by a Forster mechanism.

FIG. 7B is a diagram showing color conversion by energy transfer. As shown in FIG. 7B, in the organic phosphor, energy transfer may occur from the molecule A in the excited state to the molecule B in the ground state by the Forster mechanism. In the phosphor, when the molecule A is excited and undergoes energy transfer to the molecule B, only the molecule B emits light. This energy transfer depends on the distance between molecules, the emission spectrum of molecule A, and the absorption spectrum of molecule B. When the molecule A is a host molecule and the molecule B is a guest molecule, the rate constant (movement probability) when energy is transferred is as shown in Equation (1).

In equation (1), ν is the frequency, f ′ _H (ν) is the emission spectrum of the host molecule A, ε (ν) is the absorption spectrum of the guest molecule B, N is the Avogadro constant, n is the refractive index, τ ₀ is the fluorescence lifetime of the host molecule A, R is the intermolecular distance, and K ² is the transition dipole moment (2/3 at random).

When the rate constant is large, energy transfer tends to occur between the phosphors. In order to obtain a large rate constant, it is desirable that the following conditions are satisfied.
[1] The overlap between the emission spectrum of the host molecule A and the absorption spectrum of the guest molecule is large.
[2] The extinction coefficient of guest molecule B is large.
[3] The distance between the host molecule A and the guest molecule B is small.

[1] represents the ease of resonance between two adjacent phosphors. For example, as shown in FIG. 8A, when the peak wavelength of the emission spectrum PL1 of the host molecule A is close to the peak wavelength of the absorption spectrum AB2 of the guest molecule B, energy transfer due to the Forster mechanism is likely to occur. Here, AB1 represents the absorption spectrum of the host molecule A, and PL2 represents the emission spectrum of the guest molecule B. As shown in FIG. 8B, when the guest molecule B in the ground state exists in the vicinity of the host molecule A excited by the excitation energy EE, the wave function of the guest molecule A changes due to the resonance property, and the ground state host A molecule A and an excited guest molecule B are formed. Thereby, energy transfer ET occurs between the host molecule A and the guest molecule B, and only the guest molecule B emits light.

In the above [3], the intermolecular distance at which energy transfer by the Forster mechanism occurs is usually about 10 nm. If the conditions are met, energy transfer occurs even when the intermolecular distance is about 20 nm. If the mixing ratio of the first phosphor, the second phosphor, and the third phosphor described above is used, the distance between the phosphors is shorter than 20 nm. Therefore, energy transfer by the Forster mechanism can occur sufficiently. In addition, the emission spectra and absorption spectra of the first phosphor, the second phosphor, and the third phosphor shown in FIGS. 3 and 5 sufficiently satisfy the condition [1]. Therefore, energy transfer from the first phosphor to the second phosphor and energy transfer from the second phosphor to the third phosphor occur, and the first phosphor, the second phosphor, and the third phosphor in this order. Cascade type energy transfer occurs.

In the second light guide, despite the fact that phosphors having three different emission spectra (first phosphor, second phosphor, and third phosphor) are mixed, the energy transfer by the Förster mechanism Substantially only the third phosphor emits light. The emission quantum efficiency of the third phosphor is, for example, 92%. Therefore, by mixing the first phosphor, the second phosphor, and the third phosphor in the second light guide, the light in the wavelength region up to 620 nm is absorbed, and the red having a peak wavelength of 630 nm with an efficiency of 92%. Can be emitted.

This kind of energy transfer phenomenon is unique to organic phosphors and generally does not occur with inorganic phosphors. FIG. 7A is a diagram illustrating color conversion by photoluminescence (PL). Normally, when two types of phosphors are mixed, as shown in FIG. 7A, first, phosphor A emits light with a certain efficiency (PL), enters phosphor B, and absorbs light (AB). ) And light emission (PL), light is emitted from phosphor B. In such energy transfer by photoluminescence, energy loss occurs in the light emission process in the phosphor A and the light absorption process in the phosphor B, and the energy transfer efficiency is small. On the other hand, in the color conversion in the energy transfer by the Förster mechanism shown in FIG. 7B, only the energy moves directly between the phosphors, so the energy transfer efficiency (energy conversion efficiency) is 100%, and the energy transfer is highly efficient. Can be generated.

FIG. 9 is a spectral sensitivity curve of the compound semiconductor used for the solar cell element 5 and the solar cell element 6.

In FIG. 2A, light having a wavelength of 620 nm or less out of the light L incident on the light incident surface 2 </ b> A (the first main surface 4 a of the second light guide 4) of the light guide unit 2 is emitted from the second light guide 4. Almost all of the light is absorbed by the first phosphor 8a, the second phosphor 8b, and the third phosphor 8c dispersed therein. Then, the light L2 having a wavelength larger than 620 nm that has not been absorbed by the first phosphor 8a, the second phosphor 8b, and the third phosphor 8c passes through the second light guide 4 and passes through the first light guide 3. Is incident on.

The spectrum of the light L1 emitted from the first end face 4c of the second light guide 4 substantially matches the emission spectrum of the third phosphor 8c. Therefore, the solar cell element 6 should just have a high sensitivity in the peak wavelength (630 nm) of the emission spectrum of the 3rd fluorescent substance 8c. As shown in FIG. 9, GaAs (square) has a spectral sensitivity of almost 100% for light in the wavelength region of 600 nm to 850 nm. Therefore, if a compound solar cell using GaAs is used as the solar cell element 6 installed in the second light guide 4 (fluorescent light guide), power generation can be performed with high efficiency.

The light L2 emitted from the first end face 3c of the first light guide 3 is light in a wavelength region larger than 620 nm that has passed through the second light guide 4. Therefore, the solar cell element 5 does not need to have high spectral sensitivity for light with a wavelength of 620 nm or less, and has high spectral sensitivity for light with a long wavelength such as InGaAs (triangle in FIG. 9). Any device having sensitivity may be used. For example, if a compound solar cell in which GaAs and InGaAs are stacked is used as the solar cell element 5 installed in the first light guide 3 (shape light guide), power generation can be performed with high efficiency.

The type of solar cell applied to the solar cell element 5 and the solar cell element 6 is determined according to the wavelength of light incident on the solar cell element. For example, as the solar cell element 6, an amorphous silicon solar cell having the spectral sensitivity shown in FIG. The amorphous silicon solar cell has a spectral sensitivity exceeding 90% with respect to light having a wavelength of 630 nm. Therefore, power generation can be performed with high efficiency with respect to light having a wavelength of 620 nm to 700 nm emitted from the first end face 4 c of the second light guide 4. In addition, as the solar cell element 5 and the solar cell element 6, it cannot have high spectral sensitivity for the entire wavelength region of sunlight, such as a dye-sensitized solar cell and an organic solar cell, but has a specific narrow wavelength. It is also possible to actively use solar cells that have a very high spectral sensitivity for light in the region.

11A to 13 are diagrams showing simulation results of light extraction efficiency in the first light guide 3 and the second light guide 4.

FIG. 11A is a diagram showing the light extraction efficiency of the second light guide 4.

As described above, assuming that the amount of light incident on the first main surface 4a of the second light guide 4 is 100%, light having a wavelength of 620 nm or less out of the light incident on the first main surface 4a is second. Almost all of the light is absorbed by the first phosphor 8a, the second phosphor 8b, and the third phosphor 8c included in the light guide 4. The proportion of light having a wavelength of 620 nm or less in the spectrum of sunlight is 48%. Therefore, the proportion of light absorbed by the first phosphor 8a, the second phosphor 8b, and the third phosphor 8c is 48% of the light incident on the first main surface 4a. 52% of the light that has not been absorbed by the first phosphor 8a, the second phosphor 8b, and the third phosphor 8c passes through the second main surface 4b and is emitted to the outside of the second light guide 4.

The fluorescence quantum yields of the first phosphor 8a, the second phosphor 8b, and the third phosphor 8c are all 92%. Therefore, 92% of the light absorbed by the first phosphor 8a, the second phosphor 8b, and the third phosphor 8c is converted into fluorescence. The fluorescence propagates through the second light guide 4 and is emitted from the first end face 4c. At this time, light leaking out of the second light guide 4 without being totally reflected by the first main surface 4a and the second main surface 4b due to a difference in refractive index between the second light guide 4 and the surrounding air layer. Since the ratio is 25% and the loss of light when propagating through the second light guide 4 is 5%, the ratio of the light emitted from the first end face 4c is the ratio of the light incident on the first main surface 4a. 30%.

FIG. 11B is a diagram showing the light extraction efficiency of the first light guide 3.

A part of the light incident perpendicularly to the first main surface 3 a of the first light guide 3 is reflected by the inclined surface of the groove T provided on the second main surface 3 b, and passes through the inside of the first light guide 3. It propagates toward the first end face 3c.
The ratio of the light reflected by the inclined surface of the groove T is 60% of the light incident on the first main surface 3a. The remaining 40% of light passes through the second main surface 3b and is emitted to the outside of the first light guide 3. A part of the light propagating in the first light guide 3 is refracted on the inclined surface of the groove T on the way, leaks out of the first light guide 3 outside the total reflection condition. Therefore, the ratio of the light emitted from the first end surface 3c is 25% of the light incident on the first main surface 3a.

FIG. 12 is a diagram showing the light extraction efficiency when the first light guide 3 and the second light guide 4 are laminated in this order from the light incident side.

As described above, the first light guide 3 emits 25% of the light incident perpendicularly to the first main surface 3a from the

first end surface

3c and 40% of the light incident perpendicularly to the first main surface 3a. From the second main surface 3b. The second light guide 4 converts 30% of the light incident on the first main surface 4a into fluorescence and emits the light from the first end surface 4c. Therefore, the ratio of the light emitted from the first end surface 3c of the first light guide 3 is 25% of the light incident on the first main surface 3a of the first light guide 3, and the second light guide 4 The ratio of the light emitted from the first end face 4 c is 12% of the light incident on the first main surface 3 a of the first light guide 3. Therefore, the ratio of the light emitted from the first end surface 3 c of the first light guide 3 and the first end surface 4 c of the second light guide 4 is the light incident on the first main surface 3 a of the first light guide 3. 37%.

FIG. 13 is a diagram showing the light extraction efficiency when the second light guide 4 and the first light guide 3 are stacked in this order from the light incident side.

The second light guide 4 converts 30% of the light incident on the first main surface 4a into fluorescence and emits it from the

first end surface

4c, and 52% of the light incident on the first main surface 4a is converted into the second main surface 4a. Ejected from the surface 4b. The first light guide 3 emits 25% of light incident perpendicularly to the first main surface 3a from the first end surface 3c. Therefore, the ratio of the light emitted from the first end surface 4 c of the second light guide 4 is 30% of the light incident on the first main surface 4 a of the second light guide 4, and the first light guide 3 The ratio of the light emitted from the first end surface 3 c is 13% of the light incident on the first main surface 4 a of the second light guide 4. Therefore, the ratio of the light emitted from the first end surface 4 c of the second light guide 4 and the first end surface 3 c of the first light guide 3 is the light incident on the first main surface 4 a of the second light guide 4. Of 43%.

12 and 13 are compared, the light extraction efficiency of the entire light guide unit 2 is higher in the configuration of FIG. This is because the light extraction efficiency of the second light guide 4 alone is higher than the light extraction efficiency of the first light guide 3 alone, as shown in FIG. In general, the method of guiding external fluorescence by absorbing external light and guiding the obtained fluorescence has higher light extraction efficiency than the method of guiding light by reflecting light by the inclined surface of the second main surface. . This is because phosphors can absorb and guide light incident at any angle, whereas the method of reflecting light at an inclined surface can only guide light incident at an angle less than the critical angle of the inclined surface. . Therefore, the configuration in which the second light guide 4 is disposed closer to the light incident side than the first light guide 3 is effective in increasing the light extraction efficiency.

As shown in FIG. 1, in the solar cell module 1 of the present embodiment, the second light guide 4 and the first light guide 3 are laminated in this order from the light incident side. Therefore, the light incident on the light incident surface of the light guide unit 2 (the first main surface 4a of the second light guide 4) can be efficiently incident on the solar cell element 5 and the solar cell element 6.

In the solar cell module 1, the second light guide 4 is disposed on the light incident side, and light radiated from the phosphor (light having a peak wavelength at 630 nm and a narrow half-value width) is incident on the solar cell element 5. Thus, light that is not absorbed by the phosphor (light having a wavelength greater than 620 nm) is incident on the solar cell element 6. Therefore, as the solar cell element 5 and the solar cell element 6, an inexpensive solar cell having high spectral sensitivity only in a specific wavelength region can be used.

For example, when the first light guide 3 is arranged on the light incident side as shown in FIG. 12, the solar cell element 5 has a wide wavelength range from the ultraviolet light region to the infrared light region as shown in FIG. Light is incident. Therefore, as the solar cell element 5, it is necessary to use a solar cell having high spectral sensitivity in a wide wavelength range from the ultraviolet light region to the infrared light region. As such a solar cell, for example, a compound solar cell having spectral sensitivity as shown in FIG. 14 can be considered. The solar cell in FIG. 14 is a tandem solar cell (three-layer junction compound solar cell) in which a plurality of semiconductor layers (InGaP, GaAs, and InGaAs) having different absorption wavelengths are stacked, and the specific structure is shown in FIG. It ’s like that. In FIG. 14, the white squares indicate the absorption spectrum of InGaP, the black squares indicate the absorption spectrum of GaAs, the triangles indicate the absorption spectrum of InGaAs, and the crosses indicate the sum of these three absorption spectra. Indicates.

As shown in FIG. 15, an InGaP layer 61, a GaAs layer 62, and an InGaAs layer 63 are stacked between two

electrodes

64 and 65. The solar cell in FIG. 15 has a composition and a composition ratio of a compound, and a plurality of semiconductor layers having three different band gaps are stacked. By laminating a plurality of semiconductor layers having different band gaps, the wavelength range of the light to be captured is expanded and high power generation efficiency is realized. However, in such a solar cell, since a plurality of semiconductor layers are stacked, a manufacturing process becomes more complicated as a multilayer structure is formed. In addition, since a multi-layer solar cell is likely to have crystal defects in a semiconductor layer, the power generation efficiency for each layer is generally smaller than that of a single-layer solar cell. Therefore, the power generation efficiency as expected may not be obtained.

On the other hand, as shown in FIG. 13, the second light guide 4 is disposed on the light incident side, and a configuration in which light in a specific wavelength region is selectively incident on the solar cell element 5 and the solar cell element 6 is adopted. In such a case, the solar cell element 5 and the solar cell element 6 may have any high spectral sensitivity with respect to light in a narrow wavelength region. Therefore, even when a tandem solar cell is used, the number of semiconductor layers to be manufactured can be reduced. For example, in the example of FIG. 9, a solar cell including only one GaAs layer is used as the solar cell element 6, and a solar cell including a two-layer structure of a GaAs layer and an InGaAs layer is used as the solar cell element 5.

Recent developments have proposed dye-sensitized solar cells and organic solar cells having high spectral sensitivity for a specific wavelength. These solar cells cannot perform efficient power generation in the entire wavelength region of sunlight, but are high when applied to a configuration in which power generation is limited to a specific wavelength like the solar cell module 1. Electricity can be generated with efficiency. These solar cells can be manufactured only with organic materials and coating processes, and are very low cost. If these solar cells that can be manufactured at low cost are applied to the solar cell module 1, the cost of the solar cell module 1 can be greatly reduced, and the power generation efficiency can be improved.

Table 1 shows the simulation results of the power generation amount of the solar cell modules having various configurations.

In Table 1, “Configuration Example 1” is a solar cell module having the configuration of FIG. 12, “Configuration Example 2” is a solar cell module having the configuration of FIG. 13, and “Configuration Example 3” is a light guide. It is a solar cell module of a single crystal silicon solar cell which does not use The size of the first light guide and the second light guide used in “Configuration Example 1” and “Configuration Example 2” is 10 cm × 10 cm, and the end surfaces of the first light guide and the second light guide are The “three-layer junction compound solar cell” (InGaP / GaAs / InGaS) having the spectral sensitivity shown in FIG. 14 or the “optimized solar cell” (GaAs or GaAs / InGaAs) having the spectral sensitivity shown in FIG. Is done. “Configuration example 3” is a structure in which single crystal silicon solar cells are spread over the same 10 cm × 10 cm region as the first light guide and the second light guide. The numerical values in Table 1 indicate the light incident perpendicularly to the light incident surface (“Configuration Example 1” and “Configuration Example 2”) of the light guide unit or the light receiving surface (“Configuration Example 3”) of the single crystal silicon solar cell. 1Sun (100 mW / cm ² ), the power generation efficiency of the “3-layer junction compound solar cell” is 40%, the power generation efficiency of the single crystal silicon solar cell is 15%, and the power generation efficiency of the “optimized solar cell” is It is calculated as 65%.

As shown in Table 1, when “three-layer junction solar cell” is applied to “configuration example 1”, the power generation amount is 14.8 W, and “three-layer junction solar cell” is set to “configuration example 2”. When applied, the power generation amount is 17.2W. As shown in FIGS. 12 and 13, in “Configuration Example 2”, compared with “Configuration Example 1”, the amount of power generation is increased due to the higher light extraction efficiency. Since “Configuration Example 3” does not collect light using the light guide as in “Configuration Example 1” and “Configuration Example 2”, almost all of the incident light is used for power generation. However, since the power generation efficiency of the single crystal silicon solar cell is low, the power generation amount is 13.5 W, which is smaller than “Configuration Example 1” and “Configuration Example 2”.

In “Configuration Example 2”, the configuration of FIG. 13 is adopted, so that the first solar cell installed on the end face of the first light guide has an extremely high spectral sensitivity in a limited narrow wavelength range. A solar cell ”can be used. Since such a solar cell has a smaller number of stacked semiconductor layers and fewer crystal defects in the semiconductor layer than a “three-layer junction solar cell”, the power generation efficiency of each layer is high. Therefore, the power generation efficiency of the “optimized solar cell” is 65%, which is higher than 40% of the “three-layer junction compound solar cell”, and the power generation amount is also very high at 28 W.

[Second Embodiment]
FIG. 16 is a diagram showing an absorption spectrum and an emission spectrum of the quantum dot phosphor used in the solar cell module of the second embodiment.

Quantum dot phosphors are semiconductor fine particles having a diameter of 1 nm to 10 nm. The quantum dot phosphor is a phosphor having a high fluorescence quantum yield and excellent photochemical stability. The emission wavelength of the quantum dot phosphor can be controlled by the size of the quantum dot, and the wavelength range of light that can be absorbed is wide. In addition, since light scattering hardly occurs, scattering loss is small when light propagates inside the second light guide. Therefore, high power generation efficiency can be realized.

Quantum dot phosphor materials include group I elements such as copper (Cu), silver (Ag), and gold (Au), fluorine (F), chlorine (Cl), bromine (Br), and iodine (I). Group I-VII compound semiconductors consisting of Group VII elements such as, Group II elements such as zinc (Zn), cadmium (Cd), mercury (Hg), oxygen (O), sulfur (S), selenium (Se), II-VI compound semiconductors composed of group VI elements such as tellurium (Te), group III elements such as aluminum (Al), gallium (Ga), indium (In), nitrogen (N), phosphorus (P), arsenic Group III-V compound semiconductor composed of Group V elements such as (As) and antimony (Sb), Group IV such as carbon (C), silicon (Si), germanium (Ge), tin (Sn), lead (Pb) Elemental semiconductor, carbon (C), silicon (Si), germany IV-VI composed of group IV elements such as sulfur (Ge), tin (Sn), lead (Pb) and the like and group VI elements such as oxygen (O), sulfur (S), selenium (Se) and tellurium (Te) Group compound semiconductors, and mixed crystals thereof. Among these, CdSe, InP, PbS, InN, PbSe, Cu (In, Ga) (S, Se), and mixed crystals thereof are preferable because they have absorption characteristics suitable for the spectrum of sunlight.

FIG. 17 is a diagram showing simulation results of the light extraction efficiency of the first light guide 3 and the second light guide 4. In FIG. 17, the same code | symbol is attached | subjected about the same component as the solar module 1 of 1st Embodiment, and detailed description is abbreviate | omitted.

In the second

light guide

4, 5% of the quantum dot phosphor 8d having the light emission characteristics and the absorption characteristics shown in FIG. 16 is added. As indicated by the emission spectrum indicated by the black squares in FIG. 16, the quantum dot phosphor 8d has a peak wavelength of the emission spectrum at 800 nm and absorbs light of almost all wavelengths below 800 nm. In addition, as shown in the absorption spectrum indicated by the white squares, the light having a wavelength of 800 nm or less out of the light incident on the first main surface 4a of the second light guide 4 by the quantum dot phosphor 8d. All absorbed. In the sunlight spectrum, the proportion of light with a wavelength of 800 nm or less is 65%. Therefore, 65% of the light incident on the first main surface 4a is absorbed by the quantum dot phosphor 8d, and the remaining 35% is transmitted through the second main surface 4b and incident on the first light guide 3.

The quantum quantum yield of the quantum dot phosphor 8d is 35%. Therefore, 35% of the light absorbed by the quantum dot phosphor 8d is converted into fluorescence. Considering the loss of light when the fluorescence propagates inside the second light guide 4, the ratio of the light emitted from the first end face 4 c of the second light guide 4 is the first of the second light guide 4. This is 20% of the light incident on the main surface 4a.

As shown in FIG. 11B, the first light guide 3 emits 25% of the light incident perpendicularly to the first main surface 3a from the first end surface 3c. Therefore, the ratio of the light emitted from the first end surface 3 c of the first light guide 3 is 9% of the light incident on the first main surface 4 a of the second light guide 4. Therefore, the ratio of the light emitted from the first end surface 4 c of the second light guide 4 and the first end surface 3 c of the first light guide 3 is the light incident on the first main surface 4 a of the second light guide 4. Of 29%.

In the above example, since the fluorescence quantum yield of the quantum dot phosphor 8d is low, high power generation efficiency cannot be obtained as compared with the solar cell module 1 of the first embodiment. However, the quantum quantum yield of the quantum dot phosphor can theoretically be 100%, and if the fluorescence quantum yield is increased, a larger power generation efficiency can be obtained.

[Third Embodiment]
FIG. 18 is a cross-sectional view of the solar cell module 11 of the third embodiment. Constituent elements common to the solar cell module 1 of the first embodiment in the solar cell module 11 are denoted by the same reference numerals, and detailed description thereof is omitted.

The solar cell module 11 is different from the solar cell module 1 of the first embodiment in that

light collecting members

12 and 13 are provided. A condensing member that condenses light emitted from the first end surface 3 c of the first light guide 3 toward the first solar cell module 5 between the first light guide 3 and the first solar cell module 5. 12 is arranged. A condensing member that condenses light emitted from the first end face 4 c of the second light guide 4 toward the second solar cell module 6 between the second light guide 4 and the second solar cell module 6. 13 is arranged.

The condensing member 12 is an integrator optical element (homogenizer) that uniformizes the intensity distribution of the light emitted from the first end face 3 c of the first light guide 3 and emits it to the solar cell element 5. The condensing member 12 includes a light incident surface 12a, a light exit surface 12b, and a reflective surface 12c. The light incident surface 12 a faces the first end surface 3 c of the first light guide 3. The light emission surface 12b emits light incident from the light incident surface 12a. The reflecting surface 12c reflects the light incident from the light incident surface 12a and propagates it to the light emitting surface 12b.

The condensing member 12 has, for example, a quadrangular pyramid shape having the light incident surface 12a as the bottom surface, the light exit surface 12b as the top surface, and the reflecting surface 12c as the side surface. The condensing member 12 is formed by, for example, injection molding a resin such as polymethyl methacrylate (PMMA). The reflection surface 12c reflects light by total reflection. However, a reflection layer made of a metal film or a dielectric multilayer film may be formed on the reflection surface 12c, and the reflection layer 12c may reflect light. .

The solar cell element 5 is disposed with its light receiving surface facing the light exit surface 12 b of the light collecting member 12. The light from the first light guide 3 that has entered the light incident surface 12 a of the light collecting member 12 has a uniform illuminance distribution while being repeatedly reflected by the reflecting surface 12 c of the light collecting member 12. Then, light with uniform illuminance distribution is incident on the solar cell element 5. By making the illuminance distribution of the light incident on the solar cell element 5 uniform, the power generation efficiency of the solar cell element 5 can be increased.

The condensing member 13 is an integrator optical element (homogenizer) that equalizes the intensity distribution of the light emitted from the first end face 4 c of the second light guide 4 and emits it to the solar cell element 6. The condensing member 13 includes a light incident surface 13a, a light exit surface 13b, and a reflective surface 13c. The light incident surface 13 a faces the first end surface 4 c of the second light guide 4. The light emission surface 13b emits light incident from the light incident surface 13a. The reflecting surface 13c reflects the light incident from the light incident surface 13a and propagates it to the light emitting surface 13b. The function and configuration of the light collecting member 13 are the same as those of the light collecting member 12.

The solar cell element 6 is disposed with the light receiving surface facing the light emitting surface 13b of the light collecting member 13. The light from the second light guide 4 that has entered the light incident surface 13 a of the light collecting member 13 has a uniform illuminance distribution as it is repeatedly reflected by the reflecting surface 13 c of the light collecting member 13. Then, the light with uniform illuminance distribution is incident on the solar cell element 6. The power generation efficiency of the solar cell element 6 can be increased by making the illuminance distribution of the light incident on the solar cell element 6 uniform.

In the solar cell module 11, light emitted from the first end surface 3 c of the first light guide 3 and the first end surface 4 c of the second light guide 4 is collected and incident on the solar cell element 5 and the solar cell element 6. I am letting. Therefore, size reduction of the solar cell element 5 and the solar cell element 6 and cost reduction of the solar cell module 11 can be achieved.

[Fourth Embodiment]
FIG. 19 is a cross-sectional view of the solar cell module 21 of the fourth embodiment. Constituent elements common to the solar cell module 1 of the first embodiment in the solar cell module 21 are denoted by the same reference numerals, and detailed description thereof is omitted.

The solar cell module 21 is different from the solar cell module 1 of the first embodiment in that the light emitted from the first end surface 3 c of the first light guide 3 and the first end surface 4 c of the second light guide 4 are emitted. The light is received by one solar cell element 22, the light emitted from the first end face 3 c of the first light guide 3 and the first end face 4 c of the second light guide 4. This is a point in which a light collecting member 23 for condensing light toward the solar cell element 22 is provided.

For example, the light collecting member 23 equalizes the intensity distribution of light emitted from the first end surface 3 c of the first light guide 3 and the first end surface 4 c of the second light guide 4 and emits the light to the solar cell element 22. It is an integrator optical element (homogenizer).

The condensing member 23 includes a light incident surface 23a, a light exit surface 23b, and a reflective surface 23c. The light incident surface 23 a faces the first end surface 3 c of the first light guide 3 and the first end surface 4 c of the second light guide 4. The light emission surface 23b emits light incident from the light incident surface 23a. The reflecting surface 23c reflects the light incident from the light incident surface 23a and propagates it to the light emitting surface 23b.

The condensing member 23 has, for example, a quadrangular pyramid shape having the light incident surface 23a as the bottom surface, the light exit surface 23b as the top surface, and the reflecting surface 23c as the side surface. The condensing member 23 is formed, for example, by injection molding a resin such as polymethyl methacrylate (PMMA). The reflection surface 23c reflects light by total reflection, but a reflection layer made of a metal film or a dielectric multilayer film may be formed on the reflection surface 23c so that the reflection layer 23 reflects light. .

The solar cell element 22 is disposed with the light receiving surface facing the light emitting surface 23 b of the light collecting member 23. The light from the first light guide 3 and the light from the second light guide 4 incident on the light incident surface 23 a of the light collecting member 23 have an illuminance distribution while being repeatedly reflected by the reflective surface 23 c of the light collecting member 23. It is made uniform. Then, the light having a uniform illuminance distribution is incident on the solar cell element 22. By making the illuminance distribution of light incident on the solar cell element 22 uniform, the power generation efficiency of the solar cell element 22 can be increased.

As the solar cell element 22, a known solar cell such as a silicon solar cell, a compound solar cell, or an organic solar cell can be used. Among these, a compound solar cell using a compound semiconductor is suitable as the solar cell element 22 because it enables highly efficient power generation.
Although compound solar cells are generally expensive, the area of the solar cell element 22 can be kept small because light can be collected by the first light guide 3, the second light guide 4 and the light collecting member 23. It is done. Therefore, an increase in member cost can be suppressed.

Both the light emitted from the first end face 4 c of the second light guide 4 and the light emitted from the first end face 3 c of the first light guide 3 are incident on the solar cell element 22. Therefore, the solar cell element 22 has a spectral sensitivity with respect to both the light emitted from the first end face 4 c of the second light guide 4 and the light emitted from the first end face 3 c of the first light guide 3. High solar cells are used.

That is, the light emitted from the first end face 4c of the second light guide 4 is light having a peak wavelength at 630 nm shown in FIG. 3 (light having substantially the same spectrum as the emission spectrum of the third phosphor 8c). is there. The light emitted from the first end face 3c of the first light guide 3 is light having a wavelength larger than 620 nm shown in FIG. Therefore, a tandem solar cell in which GaAs and InGaAs shown in FIG. 9 are stacked may be used as the solar electric element 22. Thereby, highly efficient power generation can be performed for light of all wavelengths incident on the solar cell element 22.

In the solar cell module 21, light emitted from the first end surface 3 c of the first light guide 3 and the first end surface 4 c of the second light guide 4 is condensed and made incident on the solar cell element 22. Therefore, size reduction of the solar cell element 22 and cost reduction of the solar cell module 21 can be achieved. Further, since the solar cell element 22 is a common solar cell element for the first light guide 3 and the second light guide 4, the first end surface 3c of the first light guide 3 and the second light guide. Compared with the case where a solar cell element is installed on each of the first end faces 4c of the body 4, the number of parts can be reduced.

[Fifth Embodiment]
FIG. 20 is a cross-sectional view of a second light guide (fluorescent light guide) 24 applied to the solar cell module of the fifth embodiment. The configuration other than the second light guide 24 is the same as that of the solar cell module 1 of the first embodiment. Therefore, only the configuration of the second light guide 24 will be described here. Moreover, about the structure which is common in the solar cell module 1 of 1st Embodiment, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

The second light guide 24 includes a transparent light guide 25, a fluorescent film 26, and a transparent protective film 27. The fluorescent film 26 is bonded to the first main surface 25 a of the transparent light guide 25. The bright protective film 27 covers the surface of the fluorescent film 26.

The fluorescent film 26 is a film-like phosphor layer in which the first phosphor 8a, the second phosphor 8b, and the third phosphor 8c are dispersed. The fluorescent film 26 converts part of the external light (for example, sunlight) incident on the first main surface 26 a into fluorescence and radiates it toward the transparent light guide 25. For example, the phosphor film 26 includes a PMMA resin in which 0.2% of the first phosphor 8a, the second phosphor 8b, and the third phosphor 8c are mixed in a volume ratio with respect to the PMMA resin to form a film having a thickness of 200 μm. Formed.

As the transparent light guide 25 and the transparent protective film 27, a highly transparent organic material or inorganic material such as acrylic resin, polycarbonate resin, or glass is used. For example, the transparent light guide 25 is made of an acrylic plate having a thickness of 5 mm, and the transparent protective film 27 is made of a PMMA resin film having a thickness of 200 μm. In FIG. 20, the transparent protective film 27, the fluorescent film 26, and the transparent light guide 25 are arranged in this order from the incident side of the external light L. However, as shown in FIG. You may arrange | position the transparent protective film 27 from the incident side of the external light L in this order.

The transparent light guide 25 and the transparent protective film 27 are made of a highly transparent material that does not contain a phosphor. A part of the fluorescence emitted from the fluorescent film 26 (light having a spectrum substantially the same as the emission spectrum of the third phosphor 8c shown in FIG. 3) is totally reflected inside the transparent light guide 25 and the transparent protective film 27. However, it propagates toward the end surfaces of the transparent light guide 25 and the transparent protective film 27. The light emitted from the end surfaces of the transparent light guide 25 and the transparent protective film 27 enters the solar cell element and is used for power generation.

The fluorescent film 26 and the transparent light guide 25 are bonded together by a peelable adhesive layer 28 as shown in FIG. The fluorescent film 26 is peeled off from the transparent light guide 25 and replaced when damage, deterioration, or foreign matter (such as dust or bird droppings) adheres. The refractive indexes of the fluorescent film 26, the adhesive layer 28, and the transparent light guide 25 are all 1.49. The fluorescence emitted from the fluorescent film 26 propagates through the fluorescent film 26, the adhesive layer 28, and the transparent light guide 25 without loss. As such an adhesive layer 28, for example, a gel poly (trade name) manufactured by Panac Corporation can be used.

In the second light guide 24 configured as described above, the fluorescent film 26 and the transparent light guide 25 are bonded to each other with a peelable adhesive layer 28. Therefore, when the fluorescent film 26 is damaged, deteriorated, or has foreign matter attached (such as dust or bird droppings) and the power generation efficiency is reduced, only the fluorescent film 26 is peeled off from the transparent light guide 25 and replaced. Can do. Therefore, the cost of maintenance can be reduced compared with the case where the entire second light guide is replaced.

[Sixth Embodiment]
FIG. 23 is a cross-sectional view of the solar cell module 31 of the sixth embodiment. Constituent elements common to the solar cell module 1 of the first embodiment in the solar cell module 31 are denoted by the same reference numerals, and detailed description thereof is omitted.

The solar cell module 31 is different from the solar cell module 1 of the first embodiment in that the thickness of the first light guide (shape light guide) 32 (the thickness of the portion where the groove T is not formed) is the first end face 32c. It is the point comprised so that it may become thin gradually as it distances from. The first light guide 32 is different from the first light guide 3 of the first embodiment in that the first main surface 32a and the second main surface 32b are inclined so as to form an angle θ1. The material of the first light guide 32 and the configuration of the groove T provided on the second main surface 32b of the first light guide 32 are the same as the material of the first light guide 3 of the first embodiment and the first guide. This is the same as the groove T provided on the second main surface 3 b of the light body 3.

The angle θ1 formed by the first main surface 32a and the second main surface 32b of the first light guide 32 is, for example, 5 °. An interval in the Z direction between the first main surface 32a and the second main surface 32b (thickness of the first light guide 32) is gradually increased from the first end surface 32c toward the second end surface 32d facing the first end surface 32c. It is getting smaller. The solar cell element 5 is disposed to face the first end surface 32c having a larger cross-sectional area than the second end surface 32d.

FIG. 24 is a diagram illustrating a state in which the light L2 propagates inside the first light guide 32. FIG.

In the 1st light guide 32, it is comprised so that the space | interval of the 1st main surface 32a and the 2nd main surface 32b may spread toward the 1st end surface 32c from the 2nd end surface 32d. Therefore, when the light L2 is totally reflected by the first main surface 32a, the light traveling direction is converted so that the traveling direction of the light L2 is nearly parallel to the second main surface 32b. That is, the angle between the traveling direction and the second main surface 32b of the light L2 incident on the first main surface 32a and theta _A, the traveling direction and the second main surface 32b of the light L2 reflected by the first major surface 32a When the angle of the theta _B, the traveling direction of the light L2 so that theta _B becomes smaller than theta _a is converted. Therefore, in the process in which the light L2 propagates to the first end face 32c, the traveling direction of the light L2 gradually approaches a direction parallel to the second main surface 32b, and the number of times the light enters the groove T decreases.

When the light L2 propagates inside the first light guide 32, the light L2 incident on the groove T is largely refracted by the groove T and cannot be totally reflected by the first main surface 32a or the second main surface 32b. May leak to the outside. Such light loss increases as the propagation distance of the light L2 becomes longer (as the number of times the light L2 enters the groove T increases). For example, consider a case where light propagates through the first light guide having a constant thickness. In that case, if the distance between the first end face and the second end face is 10 cm, the proportion of light emitted from the first end face of the first light guide is incident on the first main face of the first light guide. 25% of the light emitted. If the distance between the first end face and the second end face is 30 cm, the ratio is 10%, and if the distance between the first end face and the second end face is 1 m, the ratio is 2%.

In the first light guide in which the first main surface and the second main surface are arranged in parallel, when the propagation distance of light increases, the number of times light enters the groove increases in proportion to the propagation distance. However, when the first main surface 32a and the second main surface 32b are arranged non-parallel as shown in FIG. 24, the number of times the light L2 is incident on the groove T is increased even if the propagation distance of the light L2 increases. Not so much. For example, when the simulation is performed with the angle formed by the first main surface 32a and the second main surface 32b being 5 °, when the distance between the first end surface 32c and the second end surface 32d is 10 cm, the first light guide The ratio of the light L2 emitted from the first end surface 32c of 32 is 28% of the light L2 incident on the first main surface 32a of the first light guide 32, but the first end surface 32c and the second end surface 32d Even if the distance is 30 cm or 1 m, the ratio is 28%, which does not change greatly.

As described above, in the solar cell module 31 according to the present embodiment, the first main surface 32a of the first light guide 32 is inclined with respect to the second main surface 32b, so that the inside of the first light guide 31 is light L2. Reduces the number of total reflections. Therefore, it is possible to provide a solar cell module in which light loss caused by the light L2 being refracted in the groove T is reduced, and the light extraction efficiency is not greatly reduced by long-distance propagation. In the method of guiding light by reflecting light at the groove T like the first light guide, the loss of light during propagation is large, so the size of the first light guide is increased to increase the light extraction amount. Even in such a case, the light amount as expected may not be obtained, but in the solar cell module 31 of the present embodiment, such a problem is improved, so that the first light guide 32 is enlarged and sufficient. It is possible to obtain a light extraction amount.

[Seventh Embodiment]
FIG. 25 is a cross-sectional view of the solar cell module 41 of the seventh embodiment. Constituent elements common to the solar cell module 31 of the sixth embodiment in the solar cell module 41 are denoted by the same reference numerals, and detailed description thereof is omitted.

The solar cell module 41 is different from the solar cell module 31 of the sixth embodiment in that the thickness of the second light guide (fluorescent light guide) 42 (the thickness of the portion where the groove T is not formed) is the first end face 42c. It is the point comprised so that it may become thin gradually as it distances from. The second light guide 42 is different from the second light guide 4 of the sixth embodiment in that the first main surface 42a and the second main surface 42b are inclined so as to form an angle θ1. The material of the second light guide 42 and the type and concentration of the phosphor included in the second light guide 42 are included in the material of the second light guide 4 and the second light guide 4 of the sixth embodiment. It is the same as the type and concentration of the phosphor.

The angle θ1 formed by the first main surface 42a and the second main surface 42b of the second light guide 42 is the same as the angle θ1 formed by the first main surface 32a and the second main surface 32b of the first light guide 32. It is. The first main surface 32 a of the first light guide 32 and the second main surface 42 b of the second light guide 42 are parallel to each other, and the second main surface 32 b of the first light guide 32 and the second light guide 42 are used. The first main surface 42a is parallel to the first main surface 42a. The first end face 32c of the first light guide 32 and the first end face 42c of the second light guide 42 face in opposite directions.

The Z-direction interval (thickness of the second light guide 42) between the first main surface 42a and the second main surface 42b of the second light guide 42 is the first distance from the first end surface 42c to the first end surface 42c. 2 gradually decreases toward the end face 42d. The light radiated from the phosphor inside the second light guide 42 is totally reflected by the first main surface 42a and the second main surface 42b of the second light guide 42. Since the two principal surfaces 42b are arranged obliquely, the totally reflected light is easily collected in the direction in which the thickness of the second light guide 42 is large. Therefore, the solar cell element 6 is disposed to face the first end surface 32c having a larger cross-sectional area than the second end surface 42d.

In the solar cell module 41, the thick part and the thin part of the first light guide 32 and the second light guide 42 are arranged to overlap each other. Therefore, the overall thickness of the first light guide 32 and the second light guide 42 laminated is uniform, and the handleability is improved.

[Eighth Embodiment]
FIG. 26A is a cross-sectional view showing the configuration of two types of first light guides (first light guide 52 and first light guide 53) applied to the solar cell module of the eighth embodiment. FIG. 26B is a cross-sectional view of the groove T provided on the second main surface of the first light guide (shape light guide) 52 and the first light guide (shape light guide) 53.

The solar cell module of the present embodiment is different from the solar cell module 1 of the first embodiment in that a plurality of (two in the present embodiment) first light guides 52 and first light guides are used as the first light guide. That is, the body 53 is laminated. That is, the second light guide 4 shown in FIG. 1 is laminated on the light incident side of the first light guide 52. The second light guide 4, the first light guide 52 and the first light guide 53 are stacked in order from the light incident side, and these three light guides (the second light guide 4 and the first light guide are stacked). 52 and the first light guide 53) constitute a light guide unit.

Therefore, here, only the configurations of the first light guide 52 and the first light guide 53, which are different from the first embodiment, will be described. Moreover, about the structure which is common in the solar cell module 1 of 1st Embodiment, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

The first light guide 52 includes a first main surface 52a that is a light incident surface, a second main surface 52b that faces the first main surface 52a, and a first end surface 52c that is a light emission surface. It is a plate-shaped member. The first light guide 53 includes a first main surface 53a that is a light incident surface, a second main surface 53b that faces the first main surface 53a, and a first end surface 53c that is a light emission surface. It is a plate-shaped member. The first light guide 52 and the first light guide 53 are arranged such that the first main surface 53a of the first light guide 53 and the second main surface 52b of the first light guide 52 face each other. The light guide 52 and the first light guide 53 are stacked in the Z direction via an air layer K (low refractive index layer) having a lower refractive index than that of the first light guide 53.

The first main surface 52a of the first light guide 52 and the first main surface 53a of the first light guide 53 are oriented in the same direction (light incident side: -Z direction). By laminating the first light guide 52 and the first light guide 53 along the light incident direction, the first light guide 52 on the previous stage side (side closer to the light incident side) could not be captured. Light can be taken in by the first light guide 53 on the rear stage side (the side far from the light incident side).

The first end face 52c of the first light guide 52 and the first end face 53c of the first light guide 53 are oriented in the same direction. The first end face 52c of the first light guide 52 and the first end face 53c of the first light guide 53 are disposed on the same plane parallel to the XZ plane. Therefore, a solar cell element 54 that receives light emitted from the first end surface 52c of the first light guide 52, and a solar cell element 55 that receives light emitted from the first end surface 53c of the first light guide 53, Can be placed in one place.

The solar cell element 54 and the solar cell element 55 generate power by using light transmitted through the second light guide 4 (see FIG. 1) arranged on the front side. Therefore, as the solar cell element 54 and the solar cell element 55, the same thing as the solar cell element 5 of 1st Embodiment can be used.

As the first light guide 52 and the first light guide 53, a highly transparent organic material or inorganic material such as acrylic resin, polycarbonate resin, or glass is used.

The second main surface 52b of the first light guide 52 and the second main surface 53b of the first light guide 53 are provided with a plurality of grooves T extending in the X direction. The groove T is a V-shaped groove in which an inclined surface T1 forming an angle θ3 with respect to a surface parallel to the XY plane and a surface T2 forming an angle θ2 with respect to a surface parallel to the XY plane intersect at a ridgeline T3. It is. A region T4 between the grooves T is a surface parallel to the XY plane. In FIG. 26A, only a few grooves T are shown to simplify the drawing, but in practice, a large number of fine grooves T with a width of about 100 μm are formed. The groove T is formed, for example, by injection molding a resin (for example, polymethyl methacrylate resin: PMMA) using a mold.

The inclined surface T1 is a reflecting surface that totally reflects light (for example, sunlight) incident from the first main surface of the first light guide and changes the traveling direction of the light toward the first end surface. Light incident at an angle close to perpendicular to the first main surface of the first light guide is reflected by the inclined surface T1 and propagates in the first light guide generally in the Y direction.

The shape of the groove T of the first light guide 52 and the shape of the groove T of the first light guide 53 are different. For example, the groove T of the first light guide 52 has an angle θ2 of 45 °, an angle θ3 of 15 °, and the width of the region T4 in the Y direction is zero. The groove T of the second light guide 53 has an angle θ2 of 90 °, an angle θ3 of 45 °, and the width of the region T4 in the Y direction is zero. The refractive index of the first light guide 52 and the second light guide 53 is 1.5.

The first light guide 52 and the first light guide 53 are different from each other in the angle θ3 of the inclined surface T1. Therefore, the incident angle ranges of light that can be taken in the first light guide 52 and the first light guide 53 are different from each other. For example, when the angle θ3 of the inclined surface T1 of the first light guide 52 is smaller than the angle θ3 of the inclined surface T1 of the first light guide 53, the first light guide 52 is shallow with respect to the first main surface 52a ( It is easy to capture light incident at a large angle with respect to the Z axis, and the first light guide 53 easily captures light incident at a deep angle (small angle with respect to the Z axis) into the first main surface 53a. Therefore, by stacking such a plurality of first light guides, it is possible to efficiently capture light incident at various angles from an oblique direction, and to suppress fluctuations in the amount of light captured due to the incident angle.

For example, the first main surface 52a is changed by changing the incident angle of light incident on the first main surface 52a of the first light guide 52 (the incident angle is 0 ° when incident from a direction parallel to the Z direction). When the ratio of the light emitted from the first end face 52c of the first light guide 52 and the first end face 53c of the first light guide 53 is simulated with respect to the light incident on the light, the ratio is obtained when the incident angle is 0 ° Is 27%, and when the incident angle is 45 °, the ratio is 32%, and it can be seen that the amount of light extraction does not change greatly depending on the incident angle.

In the solar cell module of the present embodiment, the first light guide disposed on the rear stage side of the second light guide 4 (see FIG. 1) as compared to the solar cell module 1 of the first embodiment shown in FIG. There are many bodies. Therefore, a large amount of light that cannot be captured by the second light guide 4 (see FIG. 1) can be captured by the plurality of first light guides (the first light guide 52 and the first light guide 53) on the rear stage side. . At this time, since the incident angle ranges of the light that can be captured are different from each other in the plurality of first light guides, the light incident at various angles from the oblique direction can be efficiently captured, depending on the incident angle. Variations in the amount of light taken in can also be suppressed. Therefore, stable power generation can be performed with high power generation efficiency even if the incident angle of light changes due to the movement of the sun or changes in weather.

[Ninth Embodiment]
FIG. 27 is a cross-sectional view showing configurations of two types of first light guides (first light guide 52 and first light guide 53) and a light collecting member 57 applied to the solar cell module of the ninth embodiment. It is. In the solar cell module of this embodiment, the same reference numerals are given to components common to the solar cell module of the eighth embodiment, and detailed description thereof is omitted.

The solar cell module of the present embodiment is different from the solar cell module of the eighth embodiment in that light emitted from the first end surface 52 c of the first light guide 52 and the first end surface 53 c of the first light guide 53 are used. The point where the emitted light is received by one solar cell element 56, the light emitted from the first end surface 52c of the first light guide 52, and the first end surface 53c of the first light guide 53 The light collecting member 57 for condensing the emitted light toward the solar cell element 56 is provided.

For example, the light collecting member 57 equalizes the intensity distribution of light emitted from the first end surface 52 c of the first light guide 52 and the first end surface 53 c of the first light guide 53 and emits the light to the solar cell element 56. It is an integrator optical element (homogenizer).

The condensing member 57 includes a light incident surface 57a, a light exit surface 57b, and a reflective surface 57c. The light incident surface 57 a faces the first end surface 52 c of the first light guide 52 and the first end surface 53 c of the first light guide 53. The light emission surface 57b emits light incident from the light incident surface 57a. The reflecting surface 57c reflects the light incident from the light incident surface 57a and propagates it to the light emitting surface 57b.

The condensing member 57 has, for example, a quadrangular pyramid shape having the light incident surface 57a as a bottom surface, the light exit surface 57b as a top surface, and the reflecting surface 57c as a side surface. The condensing member 57 is formed, for example, by injection molding a resin such as polymethyl methacrylate (PMMA). The reflection surface 57c reflects light by total reflection, but a reflection layer made of a metal film or a dielectric multilayer film may be formed on the reflection surface 57c so that the reflection layer 57 reflects light. .

The solar cell element 56 is disposed with its light receiving surface facing the light emitting surface 57 b of the light collecting member 57. The light from the first light guide 52 and the light from the first light guide 53 incident on the light incident surface 57 a of the light collecting member 57 have an illuminance distribution while being repeatedly reflected by the reflective surface 57 c of the light collecting member 57. It is made uniform. Then, the light with uniform illuminance distribution is incident on the solar cell element 56. By making the illuminance distribution of light incident on the solar cell element 56 uniform, the power generation efficiency of the solar cell element 56 can be increased.

The solar cell element 56 generates power by using light transmitted through the second light guide 4 (see FIG. 1) arranged on the front side. Therefore, as the solar cell element 56, the same thing as the solar cell element 5 of 1st Embodiment can be used.

In the solar cell module of the present embodiment, the light emitted from the first end surface 52 c of the first light guide 52 and the first end surface 53 c of the first light guide 53 is collected and incident on the solar cell element 56. Yes. Therefore, it is possible to reduce the size of the solar cell element 56 and reduce the cost of the solar cell module. Further, since the solar cell element 56 is a common solar cell element for the first light guide 52 and the first light guide 53, the first end surface 52c of the first light guide 52 and the first light guide are used. Compared with the case where a solar cell element is installed on each of the first end faces 53c of the body 53, the number of parts can be reduced.

[Solar power generator]
FIG. 28 is a schematic configuration diagram of the solar power generation device 1000.

The photovoltaic power generation apparatus 1000 includes a solar cell module 1001, an inverter (DC / AC converter) 1004, and a storage battery 1005. The solar cell module 1001 converts sunlight energy into electric power. The inverter 1004 converts the DC power output from the solar cell module 1001 into AC power. The storage battery 1005 stores the DC power output from the solar cell module 1001.

The solar cell module 1001 includes a light guide body 1002 that collects sunlight, and a solar cell element 1003 that generates power using sunlight collected by the light guide body 1002.
As the solar cell module 1001, for example, the solar cell module described in the first to ninth embodiments is used.

The solar power generation apparatus 1000 supplies power to the external electronic device 1006. The electronic device 1006 is supplied with power from the auxiliary power source 1007 as necessary.

Since the solar power generation device 1000 includes the solar cell module according to the above-described embodiment, the solar power generation device 1000 has a high power generation efficiency.

The aspect of the present invention can be used for a solar cell module and a solar power generation device.

DESCRIPTION OF SYMBOLS 1 ... Solar cell module, 3 ... 1st light guide (shape light guide), 3a ... 1st main surface, 3b ... 2nd main surface, 3c ... 1st end surface, 4 ... 2nd light guide (fluorescence guide) 4a ... first main surface, 4c ... first end face, 5,6 ... solar cell element, 8a, 8b, 8c, 8d ... phosphor, 12, 13 ... light collecting member, 21 ... solar cell module, 22 ... solar cell element, 23 ... condensing member, 24 ... second light guide (fluorescent light guide), 25 ... transparent light guide, 25a ... first main surface, 26 ... fluorescent film (phosphor layer), DESCRIPTION OF SYMBOLS 28 ... Adhesion layer, 31 ... Solar cell module, 32 ... 1st light guide (shape light guide), 32a ... 1st main surface, 32b ... 2nd main surface, 32c ... 1st end surface, 32d ... 2nd end surface 41 ... solar cell module, 42 ... second light guide (fluorescent light guide), 42a ... first main surface, 42b ... second main surface, 42c ... first end surface, 42d ... 2 end surfaces, 52 ... 1st light guide (shape light guide), 52a ... 1st main surface, 52b ... 2nd main surface, 52c ... 1st end surface, 53 ... 1st light guide (shape light guide) 53a ... first main surface, 53b ... second main surface, 53c ... first end surface, 54, 55 ... solar cell element, 56 ... solar cell element, 57 ... condensing member, 1000 ... solar power generation device, L, L1, L2 ... Light, T1 ... Inclined surface

Claims

A phosphor includes a first main surface and a first end surface, a part of external light incident from the first main surface is absorbed by the phosphor, and the first light emitted from the phosphor is propagated. A fluorescent light guide configured to be emitted from the first end surface;
A second main surface, a third main surface having a first inclination, and a second end surface, wherein the second light transmitted through the fluorescent light guide without being absorbed by the fluorescent material out of the external light is A solar cell module comprising: a first light guide configured to be incident from two principal surfaces, reflected and propagated by the first inclined surface, and emitted from the second end surface.
A first solar cell element that receives the first light;
A second solar cell element that receives the second light,
The solar cell module according to claim 1, wherein wavelength characteristics of spectral sensitivity of the first solar cell element and the second solar cell element are different from each other.
The solar cell module according to claim 2, wherein the fluorescent light guide includes at least two kinds of fluorescent materials having different emission spectrum peak wavelengths as the fluorescent material.
The solar cell module according to claim 3, wherein the first solar cell element receives fluorescence emitted from a phosphor having the largest peak wavelength of an emission spectrum among the at least two types of phosphors.
The spectral sensitivity of the first solar cell element at the peak wavelength of the emission spectrum of the phosphor having the largest emission spectrum peak wavelength among the at least two types of phosphors is any of the other ones provided in the fluorescence light guide. The solar cell module according to claim 4, wherein the solar cell module is larger than a spectral sensitivity of the first solar cell element at a peak wavelength of an emission spectrum of the phosphor.
The solar cell module according to claim 2, wherein the fluorescent light guide includes a quantum dot fluorescent material as the fluorescent material.
The solar cell according to claim 2, further comprising a first light collecting member that condenses the first light emitted from the first end face of the fluorescent light guide and causes the first light to enter the first solar cell element. module.
The said 1st condensing member is comprised so that intensity distribution of the said 1st light inject | emitted from the 1st end surface of the said fluorescent light guide may be equalize | homogenized, and it inject | emits to the said 1st solar cell element. The solar cell module described.
3. The sun according to claim 2, further comprising a second condensing member that condenses the second light emitted from the second end face of the first light guide and enters the second solar cell element. Battery module.
The second light collecting member is configured to uniformize the intensity distribution of the second light emitted from the second end face of the first light guide and emit the same to the second solar cell element. The solar cell module according to.
A solar cell element that receives the first light emitted from the first end face of the fluorescent light guide and the second light emitted from the second end face of the first light guide;
Injected from the first end surface of the fluorescent light guide between the solar cell element and the first end surface of the fluorescent light guide and between the solar cell element and the second end surface of the first light guide. And a condensing member configured to condense the first light and the second light emitted from the second end surface of the light guide so as to be incident on the solar cell element. Item 2. The solar cell module according to Item 1.
The condensing member equalizes the intensity distribution of the first light emitted from the first end face of the fluorescent light guide and the second light emitted from the second end face of the first light guide, and The solar cell module according to claim 11, wherein the solar cell module is configured to inject the solar cell element.
The solar cell module according to claim 1, wherein the fluorescent light guide is formed by dispersing the fluorescent material in a transparent light guide.
The said fluorescent light guide is provided with the transparent light guide and the fluorescent substance layer in which the said fluorescent substance was disperse | distributed inside provided in the 1st main surface of the said transparent light guide. Solar cell module.
The solar cell module according to claim 14, further comprising an adhesive layer that releasably adheres the transparent light guide and the phosphor layer.
The second main surface is the third main surface so that the thickness of the first light guide gradually decreases from the second end surface of the first light guide toward the third end surface facing the second end surface. The solar cell module according to claim 1, wherein the solar cell module is inclined with respect to the surface.
The fluorescent light guide includes a fourth main surface different from the first main surface, and a fourth end surface facing the first end surface,
The first main surface of the fluorescent light guide is the first of the fluorescent light guide so that the thickness of the fluorescent light guide gradually decreases from the first end surface of the fluorescent light guide toward the fourth end surface. The solar cell module of Claim 16 which inclines with respect to 4 main surfaces.
The first end face of the fluorescent light guide and the third end face of the first light guide are arranged in the same direction, and the fourth end face of the fluorescent light guide and the second end face of the first light guide are The solar cell module according to claim 17, wherein the fluorescent light guide and the first light guide are stacked so as to be arranged in the same direction.
And a second light guide having a fifth main surface, a sixth main surface, and a fifth end surface,
The first light guide is disposed between the fluorescent light guide and the second light guide,
The second light guide causes a part of the second light transmitted through the first light guide to be incident from the fifth main surface and reflected by a second inclined surface provided on the sixth main surface. The solar cell module according to claim 1, wherein the solar cell module is configured to propagate and emit from the fifth end face.
The solar cell module according to claim 19, wherein an angle of the first inclined surface and an angle of the second inclined surface are different from each other.
Furthermore, a condensing member configured to condense the second light emitted from the second end surface of the first light guide and the fifth end surface of the second light guide so as to enter the solar cell element. The solar cell module of Claim 20 provided.
The condensing member that condenses the second light emitted from the second end surface of the first light guide and the fifth end surface of the second light guide is the second end surface of the first light guide and the second end surface of the first light guide. The solar cell module according to claim 21, wherein the solar cell module is configured to make the intensity distribution of the second light emitted from the fifth end face of the two light guides uniform and emit the same to the solar cell element.
A solar power generation apparatus comprising the solar cell module according to claim 1.