JPH065477A - Multilayered solid electrolytic capacitor and its manufacture - Google Patents

Abstract

PURPOSE:To prevent a dielectric oxide film from being damaged by mechanical stress, and improve volume efficiency, by constituting electric continuity on the side surface part of anode parts which are mutually connected by a conductor bonded to each electrode part of a plurality of solid electrolytic capacitors. CONSTITUTION:An aluminum wire 1 is connected with an anode part 13 on one side of a plurality of single plate solid electrolytic capaciotors 3, by using resistance welding. A laminate 5 is obtained by bending zigzag the aluminum wire 1 part. Cathode parts of the laminate 5 are unified in a body by forming a conductive bonded layer 4. A CP wire is used as an anode lead wire, and connected with the aluminum wire 1 by using resistance welding which wire 1 is used for anode connection. As a cathode lead wire, the same wire as the anode lead wire is used and connected with a conductive adhesive agent layer 4 being a cathode part end surface of the laminate 5. Thereby mechanical stress applied to the single plate solid electrolytic capacitor can be reduced, and a laminated solid electrolytic capacitor excellent in volume efficiency can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated solid electrolytic capacitor and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, solid electrolytic capacitors have a dielectric oxide film formed on the surface of a film-forming metal such as aluminum or tantalum having a valve action, and manganese dioxide, lead dioxide or tetracyano is formed on the dielectric film. Quinodimethane complex,
Alternatively, a material in which a conductive polymer such as polypyrrole, polythiophene, or polyaniline is interposed as a solid electrolyte has been developed.

On the other hand, along with the progress of lighter, thinner, shorter and smaller electric and electronic equipments in recent years, miniaturization of electronic parts is also required, and in this, the electrolytic capacitors are becoming smaller and larger in capacity, and further on the circuit board. The demand for chip type capacitors is increasing due to the trend of surface mounting. To increase the capacity of the electrolytic capacitor and to make it into a chip, JP-A-3-21006 and JP-A-3-3006
No. 116813, etc., an etching foil made of aluminum or the like is formed, and a capacitor having a conductive polymer formed thereon is wound, or the capacitor is enclosed in a metal case, As reported in Japanese Unexamined Patent Publication No. 3-145115 of FIG. 8, a method has been developed in which the anode portions of a plurality of capacitor elements are cold-welded and then the pressure-welded portions are laser-welded and laminated.

[0004]

However, in the case of the conventional winding type electrolytic capacitor, the curved portion of the metal foil may be mechanically stressed and the electrical characteristics of the capacitor may be impaired. There is a drawback that the volume efficiency is deteriorated when it is enclosed in the case because of the gap formed in the case and because of the cylindrical shape. Further, after cold-pressing the anode part, in the method of laminating the plate-shaped capacitor by laser-welding the press-contact part, the volume efficiency deteriorates because it is necessary to form the area of the anode part relatively large, Further, as shown in FIG. 8B, the boundary portion between the anode portion and the cathode portion is curved at the time of pressure contact, so that the etching foil may be mechanically stressed, and the electrical characteristics of the capacitor may be impaired. In addition, when laser welding the pressure-welded portion, it is difficult to penetrate a plurality of metal foils with a laser and simultaneously weld them.

An object of the present invention is to prevent destruction of a dielectric oxide film by mechanical stress due to external stress when electrically connecting a plurality of single-plate solid electrolytic capacitors in parallel, and increase volumetric efficiency. It is to provide a small-sized and large-capacity laminated solid electrolytic capacitor.

[0006]

In order to achieve the above object, the present invention provides a dielectric oxide film on the surface of a film-forming metal foil having a valve action, and manganese dioxide on the dielectric oxide film. , An inorganic semiconductor such as lead dioxide, or a solid electrolytic capacitor obtained by forming a conductive polymer film such as polypyrrole, polythiophene, or polyaniline. Anodes interconnected by conductors bonded to the respective anode parts of a plurality of sheets. It is characterized in that it has electrical continuity on the side surface of the part.

In the present invention, the conductor is a metal wire,
Alternatively, a metal foil is used, and as a stacking method, continuous conductors are folded and folded. A metal wire that is a conductor,
Alternatively, it is desirable that the material of the metal foil is the same metal as the capacitor metal, or an alloy containing the same metal as a component, or the same metal as the capacitor metal, or the main component of the alloy.

[0008]

The present invention will be described below with reference to the drawings.

FIG. 3 shows a monolithic structure of the laminated solid electrolytic capacitor according to the first embodiment of the present invention.
(A) is a plan view and (b) is a sectional view taken along the line AA. As the film-forming metal having a valve action, a foil or plate material such as aluminum, tantalum, or titanium is used.

In the first embodiment, a predetermined portion of the metal foil 8 cut into a strip having a width of 3 mm was anodized in an adipic acid-based chemical conversion solution to form an anodized film 9 as a dielectric. . A polypyrrole layer 10 serving as a solid electrolyte was formed on the predetermined portion by electrolytic polymerization or chemical polymerization. Further, a graphite layer 11 and a silver paste layer 12 were sequentially formed for drawing out the cathode to obtain a single plate solid electrolytic capacitor 3 shown in FIG.

FIG. 1 is a plan view of a main process of a laminated solid electrolytic capacitor, which is shown in order of process for explaining a laminated solid electrolytic capacitor of one embodiment of the present invention and a manufacturing method thereof.
It is a perspective view and a sectional view.

First, one of the plurality of single-plate solid electrolytic capacitors 3 formed as shown in FIG.
The aluminum wire 1 of 00 μm is connected by resistance welding (FIG. 1 (a)), and the aluminum wire portion is folded in a zigzag shape (FIG. 1 (b)) to obtain a laminate 5 (5 sheets in the drawing) (FIG. 1).
(C), (d)). The cathode portion of the laminated body 5 is integrated by forming the conductive adhesive layer 4.

The laminated body 5 thus formed is shown in FIG.
The electrode terminals such as That is, as the anode lead wire 14, a CP wire is used and connected to the aluminum wire 1 used for anode connection by resistance welding, and as the cathode lead wire 15, the same one as the anode lead wire 14 is used. Was connected to the conductive adhesive layer 4 using a silver-based conductive adhesive. Thereafter, as shown in FIG. 6, the element portion was packaged with epoxy resin or the like to form a lead type, and the dip-type laminated solid electrolytic capacitor of the first embodiment was completed.

Further, in FIG. 5 as the second embodiment, the anode side is connected to the lead frame 15 designed as a chip type terminal by welding and the cathode side is connected by a silver-based conductive adhesive. Next, as shown in FIG. 7, the capacitor element was packaged with an epoxy resin or the like to package the element part, and after packaging, the electrode part was extracted from the lead frame and bent along the package part to obtain a chip type. FIG. 2 is a perspective view of the third embodiment of the present invention after the belt-shaped metal foil before lamination is welded. As a third embodiment,
A single-plate solid electrolytic capacitor was formed by the same method as in the above-mentioned example, and a laminated solid electrolytic capacitor was prepared by the same method except that the aluminum wire 1 was changed to a strip-shaped metal foil 6 having a width of 1 mm.

Further, in the fourth embodiment, a single plate solid electrolytic capacitor 3 is formed in the same manner as in the first embodiment, and the aluminum wire 1 is replaced with a strip-shaped metal foil 6 having a width of 1 mm. Anode end face and width of a single plate solid electrolytic capacitor 3
mm of the strip-shaped metal foil 6 is laser-welded on the end face to form the strip-shaped metal foil 6
A method of forming a folded laminated body 5 (five sheets in the figure) by spelling the portions was also carried out. The cathode part of the laminate 5 is integrated by immersing it in a conductive adhesive.

Table 1 shows the leakage current and open failure after lamination of the laminated solid electrolytic capacitor prepared as described above. In the conventional example, after the cold pressure welding of the anode portion, the pressure welding portion 18 is welded by laser.

[0017]

[Table 1]

(A capacitor of 10 V-4.7 μF was used. The number of samples was 100. LC was measured at a value of 10 V-1 minute, and defects of 3 μA or more were determined to be defective. (−55 ° C. to 85 ° C.) It is a value after 50 cycles) As is clear from Table 1, both the LC defective rate and the open defective rate are reduced in the example as compared with the conventional example.
It is considered that the LC failure is caused by the destruction of the oxide film, and in the embodiment, the anode part of the plurality of single plate solid electrolytic capacitors is surely electrically connected through the aluminum wire or the strip-shaped metal foil. Therefore, open defects are decreasing.

In this embodiment, an aluminum wire (or foil) was used for the anode connection, but this is not limited to aluminum, but CP solder plated wire (or foil), Ni solder plated wire ( Alternatively, foil, 42 alloy wire (or foil), phosphor bronze wire (or foil), or the like may be used.

[0020]

According to the present invention, when a plurality of foil-type solid electrolytic capacitors are electrically stacked in parallel, the anode part of the single-plate solid electrolytic capacitor is preliminarily shared by a metal wire or a strip-shaped metal foil as a conductor. Since the laminated body is formed after that, it is not necessary to connect the anode after the lamination, the mechanical stress applied to the single plate solid electrolytic capacitor can be reduced, and the metal wire (or foil) between each anode is a conductor. Since the electrical continuity is surely established, the open defect is reduced, and the laminated solid electrolytic capacitor excellent in volume efficiency is obtained.

[Brief description of drawings]

FIG. 1 is a plan view, a perspective view, and a sectional view showing a manufacturing process of a laminated solid electrolytic capacitor according to a first embodiment of the present invention,
(A) After the conductor is adhered before lamination, (b) is a process diagram of the zigzag folding, and (c) and (d) are completed diagrams.

FIG. 2 is a perspective view of a laminated solid electrolytic capacitor of a third embodiment of the present invention before lamination and after welding of a strip-shaped metal foil.

3A is a plan view of a single plate solid electrolytic capacitor used in the present invention, and FIG. 3B is a sectional view taken along line AA.

FIG. 4 is a perspective view of the dip-type laminated solid electrolytic capacitor of the first embodiment of the present invention after leads are attached.

FIG. 5 is a perspective view of a chip type multilayer solid electrolytic capacitor of a second embodiment of the present invention after leads are attached.

FIG. 6 is a perspective view of the dip-type laminated solid electrolytic capacitor of the first embodiment of the present invention after being packaged.

FIG. 7 is a perspective view of the chip type solid electrolytic capacitor of the second embodiment of the present invention after being packaged.

8A is a plan view of a conventional laminated solid electrolytic capacitor, and FIG. 8B is a sectional view taken along line BB.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal wire 2 Resistance welding part 3 Single plate solid electrolytic capacitor 4 Conductive adhesive 5 Laminated body 6 Strip metal foil 7 Laser welding part 8 Metal foil 9 Anodized film 10 Polypyrrole layer 11 Graphite layer 12 Silver paste layer 13 Anode part 14 Anode lead wire 15 Cathode lead wire 16 Lead frame 17 Cold pressure welding part and laser penetration part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomoji Arai 5-7-1 Shiba, Minato-ku, Tokyo NEC Corporation

Claims (5)

[Claims] 1. A dielectric oxide film is formed on the surface of a film-forming metal foil having a valve action, and an inorganic semiconductor such as manganese dioxide or lead dioxide, or polypyrrole, polythiophene or polyaniline is formed on the dielectric oxide film. In a laminated solid electrolytic capacitor in which a plurality of solid electrolytic capacitor elements for forming a conductive polymer film such as is laminated, the anode part of each single plate solid electrolytic capacitor is electrically and mechanically formed by a series of metal wires or strip metal foils. Multilayer electrolytic capacitor characterized in that they are electrically connected. 2. A series of metal wires bonded to the respective anodes of a plurality of single-plate solid electrolytic capacitors, or a strip-shaped metal foil made of the same metal as the capacitor metal, or an alloy containing the same metal as a component. Or a metal forming an alloy with the capacitor metal, or a main component of the alloy, the multilayer solid electrolytic capacitor according to claim 1. 3. A series of metal wires or strip-shaped metal foils bonded to the respective anode parts of a plurality of single plate solid electrolytic capacitors are alternately bonded to the front and back of the single plate solid electrolytic capacitors. The laminated solid electrolytic capacitor according to claim 1. 4. A dielectric oxide film is formed on the surface of a film-forming metal foil having a valve action, and the dielectric oxide film is formed on the dielectric oxide film.
Inorganic semiconductors such as manganese dioxide and lead dioxide, or
A plurality of single-plate solid electrolytic capacitor elements with conductive polymer films such as polypyrrole, polythiophene, and polyaniline are laminated, and a series of metal wires or strip-shaped metal foils are resistance-welded to the anode part of each single-plate solid electrolytic capacitor. Or a method of manufacturing a laminated solid electrolytic capacitor, which comprises a step of adhering by laser welding and connecting electrically and mechanically. 5. The method for laminating the single-plate solid electrolytic capacitor according to claim 4, wherein the conductor between the anodes of the single-plate solid electrolytic capacitor is alternately folded and folded alternately in a mountain fold and a valley fold. Manufacturing method of laminated solid electrolytic capacitor.