DE102005007583A1 - Process for producing an anode body and anode body - Google Patents

Abstract

The invention relates to a method for producing an anode body (201, 202, 203), in which an anode conductor (21) is immersed in a metal-containing molding compound and then the molding compound adhering to the anode conductor after immersion is sintered. With the invention it is possible to provide a particularly flat capacitor with a large CV value and at the same time a low ESR value.

Description

It is described a method for producing an anode body or a capacitor element for an electrical capacitor.

From the pamphlets DE 10057488 A1 and DE 20203300 A1 are z. As tantalum or niobium capacitors known. The capacitor element has an anode body with a protruding anode conductor, a dielectric layer and a cathode layer.

A to be solved The object is a method for producing an anode body for a capacitor specify that is particularly compact.

It a method for the production of a rod-shaped anode body is given, at first an anode conductor and a suitable for forming an anode body Mold compound is provided. The molding composition preferably contains a metal-containing powder and a binder, wherein the binder content preferably at least 1 percent by weight, in a variant at least 30 Weight percent. The molding composition may, for. B. contain tantalum particles. The anode conductor is immersed in the molding compound (possibly several times), and at the Anodenableiter sintered after removal adhesive molding compound.

The at the anode arrester adhesive molding compound may preferably before sintering -. B. by pressing - too be formed in a front of some variant cuboid bar. The adhesive on anode conductor molding compound can in a variant before sintering - z. B. by rolling the Anodenableiters with the adhering to him molding compound against a hard pad - too a cylindrical one Rod are shaped.

Under a rod is a body to understand where the ratio his length at least to its cross-sectional size is the factor 2. The Use of several rod-shaped anode body instead of just one anode body in a capacitor housing has the advantage that thereby the externally contactable surface of the anode body or the corresponding capacity element is enlarged.

In an advantageous variant is a molding compound with a low Binder content, z. B. less than 10% used. In a variant is the molding material even in the form of a loose or dry - d. H. no binder-containing metal powder provided.

Of the Anodenableiter is first moistened by dipping in a binder and then in the metal powder immersed, with the metal particles at all Stick sides of the moistened rod. The metal particles are moistened by the binder or mix with the binder Binder and form a layer of adhering to the Anodenableiter Molding compound. It is advantageous to use the anode conductor with it adhesive metal particles again in the binder and then in the Metal powder or in the molding compound with the low binder content (if necessary, take turns several times). It will be at the anode conductor further layers of the molding compound on top of each other formed, which together later Ano denkörper form. After molding the molding compound, the anode body is sintered.

In A variant is a wet-chemical deposition of metal particles at the Anodenableiter from an emulsion possible. The emulsion contains a suitable one liquid Solvent, in which the metal particles float. Subsequent shaping of the anode body is not necessarily in this case required.

Preferably is applied to the inner and outer surface of the sintered porous Anodenkörpers, z. In a wet chemical process, a dielectric layer (Preferably, an oxide layer) and then one - the counter electrode or the Cathode layer forming - metal layer applied. The anode body, the anode conductor and the cathode layer together form one rod-shaped capacity in a capacitor can be used.

Preferably become several in one case Capacitor Elements (Capacities) arranged side by side. The capacitor elements are thereby anoden- and connected on the cathode side and enclosed by a housing. The from the casing outstanding connections are shaped so that an electrical contact is made possible.

Various arranged in the common housing Capacitor elements are preferably electrically interconnected inside the housing connected, for example, in a preferred variant in parallel interconnected with each other. This succeeds in a particularly flat Capacitor with a large one CV value and at the same time provide a low ESR value.

The arranged at the same height Anodenableiter, the various, in a row arranged associated with capacitor elements, each z. B. be connected by soldering firmly to a common anode terminal. The outer cathode layers of different, arranged in a row capacitor elements can each be firmly connected to a common cathode terminal.

in the The following is a capacitor and a method based on embodiments and its associated Figures closer explained. The figures show by schematic and not to scale Representations of various embodiments. The same or equal parts are denoted by the same reference numerals designated. It show schematically

1 a front perspective view of a capacitor having a plurality of rod-shaped anode bodies whose anode leads represent wires;

2 a front perspective view and the construction of the capacitor whose anode body strip-shaped Anodenableiter, from below.

3A . 3B Process steps in the production of a rod-shaped anode body.

In 1 a capacitor made in the method described above is shown. The capacitor has a housing 10 and a plurality of capacitor elements arranged side by side in this housing. The housing 10 is preferably produced in an injection molding process from an injection-moldable plastic. Each capacitor element corresponds to a separate anode body 201 . 202 and 203 , The anode body 201 . 202 . 203 is, for example, a porous sintered body of tantalum powder. From the inside of the anode body is an anode conductor 21 led out. The anode conductor 21 is fixed with an anode connection 11 connected to the capacitor.

The relationship the length of the anode body to its cross-sectional size is preferably at least factor 2.

The capacitor elements are arranged in a row, on the anode side with a common anode connection 11 and on the cathode side with a common cathode connection 12 of the capacitor electrically or mechanically firmly connected.

Preferably, on the entire surface of the anode body, a dielectric layer, not shown here, is produced, on which an electrically conductive cathode layer 22 is applied, which with a cathode connection 12 the capacitor is firmly connected.

The anode body associated with the various capacitor elements 201 . 202 and 203 are arranged in a row, so that the anode conductor 21 the arranged in a row capacitor elements are brought to a plane. All anode arresters are made with a single anode contact 11 firmly connected, see 2 , Also all cathode layers 22 Different capacitor elements are fixed with a single cathode contact 12 connected.

In the 1 shown Anodenableiter represent protruding from the anode body wires or rods. The Anodenableiter can in another, in 2 be presented variant band-shaped. The rod-shaped anode body 201 to 203 have in the 1 and 2 a right square, square, circular or other cross-section. It is also possible to form the rod-shaped anode body in a cylindrical shape.

3A shows a molding compound 3 containing a metal-containing powder mixed with a binder (eg camphor). The powder may in particular contain tantalum particles. The rod-shaped or band-shaped anode conductor 21 is immersed at least once, but preferably several times in the molding compound, which is indicated in the figure with the arrows.

3B shows the anode conductor 21 with the adhesive thereon molding compound 31 that now z. B. is to be formed by a tool, not shown in this figure to a preferably symmetrical anode body. On the anode body, a dielectric layer is applied after sintering. On the dielectric layer, an electrically conductive or semiconductive layer is applied, which forms a cathode layer.

capacitor and methods have been described based on only a few embodiments shown. However, they are on these or certain applications not limited. As material for the anode body can Any suitable alloys or valve metals are used. Capacitors can in particular chip capacitors, z. B. tantalum or niobium capacitors be. The method can also be used for any other electrical Components are used.

10

casing

11

anode of the capacitor

12

cathode of the capacitor

201,202,203

anode body

21

anode conductor

22

cathode layer

3

molding compound

31

at the Anodenableiter adhesive molding compound

Claims (13)

Process for producing a rod-shaped anode body ( 201 . 202 . 203 ), in which an anode conductor ( 21 ) is provided, in which one for forming an anode body ( 201 . 202 . 203 ) is provided, in which the anode conductor ( 21 ) is immersed in the molding compound, in which the at the Anodenableiter ( 21 ) is sintered after dipping adhesive molding material. Method according to claim 1, wherein the at the Anodenableiter ( 21 ) adhesive molding compound is formed into a rod before sintering. The method of claim 2, wherein the molding compound is formed by pressing to the rod. Method according to claim 1, wherein the at the Anodenableiter ( 21 ) adhesive molding compound is formed prior to sintering into a cylindrical rod. Process according to Claim 4, in which the molding composition is obtained by rolling the anode conductor ( 21 ) is formed with the adhering to it molding compound against a hard surface to the cylindrical rod. Method according to one of claims 1 to 5, wherein a molding material is used, which contains a metal-containing powder and a binder, wherein the Binder content is at least 1%. Method according to one of claims 1 to 6, in which as an anode conductor ( 21 ) a wire is used. Method according to one of claims 1 to 7, wherein a molding material which is a metal powder and a low binder content between 0 and 10%. Method according to claim 8, wherein the anode conductor ( 21 ) is alternately immersed in the binder and in the molding compound alternately. Process for producing a rod-shaped anode body, in which an anode conductor ( 21 ), in which an emulsion is provided with metal particles floating in a liquid solvent, in which the anode conductor ( 21 ) is immersed in the emulsion, wherein the metal particles are wet-chemically deposited on the Anodenableiter, wherein an anode body is formed, which is then sintered. Anode body for a solid electrolytic capacitor, wherein the anode body ( 201 . 202 . 203 ) is rod-shaped. anode body according to claim 11, wherein the ratio his length at least to its cross-sectional size Factor is 2. anode body according to claim 11 or 12, wherein from its interior an anode wire protrudes.