JP3135072B2 - Method for manufacturing solid electrolytic capacitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a solid electrolytic capacitor using a conductive polymer film as a solid electrolyte.

[0002]

2. Description of the Related Art There has been proposed a solid electrolytic capacitor having a structure in which a dielectric oxide film is formed on the surface of a valve metal and a conductive polymer film is formed on the dielectric oxide film to form a solid electrolyte. In order to apply a conductive polymer film by electrolytic polymerization as a solid electrolyte, after forming a conductive polymer film by chemical oxidation polymerization as a pre-coat layer on a dielectric oxide film, and then apply electrolytic polymerization on the conductive polymer film There has been proposed a solid electrolytic capacitor having a structure in which a conductive polymer film is formed to be a solid electrolyte (JP-A-63-173313). In addition, after forming a conductive metal compound thin film such as manganese dioxide as a precoat layer on a dielectric oxide film, a conductive polymer film is formed on the thin film by electrolytic polymerization to form a solid electrolyte. Capacitor (JP-A 63-1588)
29) has been proposed. These capacitors have excellent frequency characteristics, electrical characteristics, and heat resistance as compared with conventional capacitors.

[0003] In these solid electrolytic capacitors, there is known a method of winding or laminating an aluminum foil to obtain a large area in order to take advantage of the inherent small size and large capacity of the aluminum electrolytic capacitor. There are drawbacks such as complicated processes and damage to the dielectric oxide film during production.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a solid electrolyte having a structure in which a dielectric oxide film is formed on a valve metal surface and a conductive polymer film is formed on the dielectric oxide film. It is an object of the present invention to provide a method for manufacturing a solid electrolytic capacitor having a small size and a large capacity, which is simple in process and does not impair the capacitor characteristics, and a method for manufacturing a solid electrolytic capacitor by lamination.

[0005]

As a result of intensive studies, the present inventors have completed a method for manufacturing a solid electrolytic capacitor which solves the above-mentioned problems. That is, a step of forming a plurality of patterns by coating the surface of a long valve metal having a dielectric oxide film formed thereon with an insulating resin except for a desired portion including an anode extraction portion and an end surface portion, A step of forming a conductive precoat layer on a desired portion, a step of laminating a long valve-action metal so that a plurality of patterns overlap,
A step of joining the laminates by electric or mechanical means for each pattern, a step of re-chemical formation, a step of forming a conductive polymer film by electrolytic polymerization, and forming a cathode conductive coating layer with carbon and silver paste A method for manufacturing a solid electrolytic capacitor, comprising a step of cutting a plurality of patterns at an insulating resin portion.

According to the method for manufacturing a solid electrolytic capacitor of the present invention, a small-sized and large-capacity solid electrolytic capacitor can be manufactured by a simple process without deteriorating the characteristics of the capacitor.

An embodiment of the present invention will be described below with reference to the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As a valve metal, aluminum, tantalum or titanium is used in a foil or plate shape. Next, a case where the present invention uses aluminum as a valve metal in a foil form will be described. After etching the surface of the large-area aluminum foil, electrolytic oxidation is performed in an aqueous solution of ammonium adipate or the like to form a dielectric oxide film on the surface. The foil is cut into a long shape, and the cut end face is also subjected to a chemical conversion treatment. The cutting width varies depending on the size of the target capacitor, but is generally several mm to several cm. The long aluminum foil is handled by winding it on a reel.

As shown in FIG. 1, an anode extraction portion 2 on the surface of a long aluminum foil 1 on which a dielectric oxide film is formed
Except for the desired portion 4 including the end portion 3 and the insulating resin 5
Cover with. Coating is performed by a reverse coater, screen printing, or the like. As the insulating resin, a high heat-resistant insulating polymer material such as a silicon resin, an epoxy resin, a fluorine resin, a polyimide resin, and a polyphenylene sulfide resin is used. In the above process, after a plurality of patterns are formed in advance on a large-area aluminum foil with an insulating resin, the resultant is cut into a long shape in accordance with this pattern, and the end face is covered with the insulating resin. A long foil similar to that of FIG. 1 can be obtained.

A conductive precoat layer 6 is formed on a desired portion 4 including an anode extraction portion and an end surface portion, and is wound into a reel. Examples of the method for forming the precoat layer include a method for forming a conductive polymer film by chemically oxidizing and polymerizing a conductive polymer monomer, and a method for forming a conductive manganese dioxide layer by thermal decomposition of a manganese salt. There are a method of forming a thin film, a method of impregnating and drying a solvent-soluble conductive polymer such as polyaniline, and a solution of a tetracyanoquinodimethane complex.

Next, as shown in FIG. 2, a long aluminum foil on which a conductive precoat layer 6 is formed is laminated so that the patterns overlap. Next, the laminated foils are joined together by electrical or mechanical means such as welding or caulking at the anode lead-out portion. At this time, the anode leads 7 may be joined together. FIG. 2 is a diagram in which three aluminum foils are laminated. Thereafter, re-chemical conversion is performed to repair the dielectric oxide film damaged in the above steps.

Subsequently, as shown in FIG. 3, the external foil 8 having the conductive pre-coat layer formed thereon is continuously moved in the electrolytic cell 9 in which a plurality of external anodes 8 are fixed. The conductive precoat layer is brought into contact with the support electrolyte to form a supporting electrolyte of 0.01 to 2 mol / l and a conductive polymer monomer of 0.01 to 5 mol.
Electropolymerization is performed in an electrolytic solution containing l / l to form a conductive polymer film by electrolytic polymerization.

As shown in FIG. 4, a fixed external anode 8 is provided.
Has two rotatable cylinders facing each other, and the laminated foil 10 on which the conductive precoat layer is formed comes into contact while moving between the rotating anodes. Does not damage. The portion where the insulating resin is not applied on the end surface becomes an opening, and the electrolyte sufficiently penetrates into the internal voids, and the conductive polymer film by uniform electrolytic polymerization also on the laminated inner conductive precoat layer Is formed. As the conductive polymer monomer, pyrrole, thiophene, and furan are used, and pyrrole is particularly preferably used in terms of stability.

Thereafter, as shown in FIGS. 5 and 6, the laminated foil is immersed in a carbon paste and a conductive paste to form a conductive coating layer 12 on the conductive polymer film 11 by electrolytic polymerization. Then, the cathode lead 13 is taken out from a part thereof. Further, each pattern portion is cut at the cut portion 14 of the insulating resin coating film portion to cut out a large number of elements, and these elements are sealed in a resin mold or an outer case. FIG.
It is sectional drawing of the capacitor element after cutting. The shapes of the cathode lead and the anode lead and the extraction method are not limited to the above-described embodiment of the present invention.

[0013]

According to the method for manufacturing a solid electrolytic capacitor of the present invention, a small and large-capacity solid electrolytic capacitor by lamination can be continuously produced by a combination of simple steps. Further, since the re-formation is performed after the mechanical stress is applied, the leakage current is small and the capacitor characteristics are not deteriorated.

[Brief description of the drawings]

FIG. 1 is a diagram in which a long aluminum foil is covered with an insulating resin.

FIG. 2 is a diagram in which three long aluminum foils are laminated.

FIG. 3 is a view showing a method of electrolytic polymerization.

FIG. 4 is a diagram showing an external anode.

FIG. 5 is a diagram of a process of cutting out each pattern.

FIG. 6 is a sectional view of the capacitor element after cutting.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Aluminum foil on which dielectric oxide film is formed 2 Anode lead-out part 3 End face part 4 Desired part including anode lead-out part and end face part 5 Insulating resin 6 Conductive pre-coat layer 7 Anode lead 8 External anode 9 Electrolytic tank 10 Conductivity Laminated foil with conductive pre-coat layer 11 Conductive polymer film by electrolytic polymerization 12 Conductive coating layer 13 Cathode lead 14 Insulation resin coating film cut portion

Continuation of front page (56) References JP-A-1-232712 (JP, A) JP-A-63-244610 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01G 9 / 00 H01G 9/028 H01G 9/04

Claims (1)

(57) [Claims] 1. A plurality of patterns are formed by coating a surface of a long valve metal having a dielectric oxide film formed thereon with an insulating resin on portions other than a desired portion including an anode extraction portion and an end surface portion. A step of forming a conductive pre-coat layer on the desired portion, a step of laminating a long valve metal so that a plurality of patterns overlap, and a step of electrically or laminating the laminated plates for each pattern. Steps of joining by mechanical means, steps of re-chemical formation, steps of forming a conductive polymer film by electrolytic polymerization, steps of forming a cathode conductive coating layer with carbon and silver paste, a plurality of patterns formed of insulating resin A method for manufacturing a solid electrolytic capacitor, comprising a step of cutting with a solid electrolytic capacitor.