JP2012190819A - Solid electrolytic capacitor, and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid electrolytic capacitor capable of making miniaturization compatible with reduction of ESR, and a method of manufacturing the same.SOLUTION: This solid electrolytic capacitor includes a laminate in which a plurality of valve action metal substrates each having a first principal surface and a second principal surface facing each other, and side faces continuously connecting them, and having a positive electrode extracting part and a negative electrode layer forming part are laminated, and the positive electrode extracting part and/or the negative electrode forming part are bonded each other, dielectric oxide films formed on the first principal surface, the second principal surface, and the side faces in the negative electrode layer forming part of the valve action metal substrate, and a solid electrolyte formed so as to cover the dielectric oxide film in the negative electrode layer forming part of the valve action metal substrate. In the first principal surface and/or the second principal surface of at least one or more valve action metal substrates constituting the laminate, at least the negative electrode layer forming part is contained, a recessed part is formed so that at least one end thereof is exposed to the side face in the negative electrode layer forming part, and a conductive part is disposed in the recessed part in the negative electrode layer forming part of the valve action metal substrate.

Description

  The present invention relates to a solid electrolytic capacitor and a method for manufacturing the same.

  Along with the high density mounting and high frequency of electronic equipment, a solid electrolytic capacitor, which is one of electronic components, is required to achieve both a reduction in size and a reduction in equivalent series resistance (hereinafter sometimes referred to as ESR).

  A conventional solid electrolytic capacitor is composed of a dielectric oxide film, a solid electrolyte, and a laminate in which a plurality of valve action metal substrates having a cathode layer formed on the surface thereof are stacked. Such a solid electrolytic capacitor is disclosed in Patent Document 1, for example.

  On the other hand, a multilayer body in which a plurality of valve action metal substrates each having a solid electrolyte and a cathode layer that are not formed and having only a dielectric oxide film are stacked is manufactured, and after the laminate is manufactured, between the valve action metal substrates constituting the laminate A solid electrolytic capacitor having no cathode layer in the gap between the valve metal substrates constituting the laminate can be produced by the production method of forming the solid electrolyte so as to cover the gap and the outer surface of the laminate. Such a solid electrolytic capacitor is disclosed in Patent Document 2, for example.

Japanese Patent Laid-Open No. 2004-87893 Japanese Patent No. 4458470

  The solid electrolytic capacitor of Patent Document 1 has a problem in that miniaturization is hindered because a cathode layer is formed between valve-acting metal substrates constituting the laminate.

  In addition, the solid electrolytic capacitor of Patent Document 2 can be reduced in size because it does not have a cathode layer in the gap between the valve metal substrates constituting the laminate. However, since the gap between the valve action metal substrates has only a solid electrolyte whose conductivity is not sufficiently higher than that of the cathode layer, the conductivity of the gap between the valve action metal substrates becomes insufficient, and the solid electrolytic capacitor There was a problem that the ESR of the system increased.

  Accordingly, an object of the present invention is to provide a solid electrolytic capacitor that can be reduced in size and reduced in ESR, and a method for manufacturing the same.

  In order to solve the above-described problems, a solid electrolytic capacitor according to the present invention has a first main surface, a second main surface, and side surfaces connecting them, which are opposed to each other, and an anode lead portion and a cathode layer are formed. A valve action metal substrate having a portion, a laminate in which a plurality of the valve action metal substrates are stacked and joined to each other at an anode lead portion and / or a cathode layer forming portion, and at least a cathode layer of the valve action metal substrate The dielectric oxide film formed on the first main surface, the second main surface, and the side surface in the forming portion, and the dielectric oxide film in the cathode layer forming portion of the valve action metal substrate are formed so as to be covered. A solid electrolytic capacitor including a solid electrolyte, wherein at least one cathode layer forming portion is provided on at least one of the first main surface and / or the second main surface of at least one valve metal substrate constituting the laminate. Including, small Kutomo one end is concave so as to expose the formed on the side surface of the cathode layer forming portion, the recess in the cathode layer forming part of the valve metal substrate, a conductor is characterized in that it is arranged.

  In the solid electrolytic capacitor according to the present invention, since a conductor having a higher conductivity than the solid electrolyte is disposed in the recess formed in the valve action metal substrate, the conduction of the gap between the valve action metal substrates constituting the laminate is performed. The rate is increased, and the ESR of the solid electrolytic capacitor can be reduced.

  Further, it is desirable that the conductor does not substantially protrude from the first main surface of the valve action metal substrate, and in that case, there is no hindrance to downsizing of the solid electrolytic capacitor.

  In addition, the method for manufacturing a solid electrolytic capacitor according to the present invention includes a first main surface, a second main surface, and a side surface connecting the first main surface and the second main surface that face each other, and a valve having an anode lead portion and a cathode layer forming portion. A laminated body forming step of preparing a working metal base, stacking a plurality of the valve metal bases, and bonding them together at an anode lead portion and / or a cathode layer forming portion, wherein the laminated body forming step comprises: At least one cathode layer forming region on at least one of the first main surface and / or the second main surface of at least one valve metal substrate constituting the at least one end in the cathode layer forming portion of the valve metal substrate. A step of forming a recess so as to be exposed on the side surface; and dielectric oxidation on the first main surface, the second main surface, and the side surface of at least the cathode layer forming portion of the valve action metal substrate constituting the laminate. Shape the film A solid electrolyte forming step of forming a solid electrolyte so as to cover the dielectric oxide film in the cathode layer forming portion of the valve action metal substrate after the laminated body forming step, It is characterized by having a conductor arrangement step of arranging a conductor in the recess in the cathode layer forming portion of the valve action metal substrate after the solid electrolyte formation step.

  In the method for manufacturing a solid electrolytic capacitor according to the present invention, after forming the multilayer body, the solid electrolyte and the conductor can be collectively formed on the valve metal substrate constituting the multilayer body. Increase efficiency.

  In the present invention, it is possible to efficiently manufacture a solid electrolytic capacitor that can be reduced in size and reduced in ESR.

1 is a perspective view, a plan view, and an exploded perspective view showing a solid electrolytic capacitor according to an embodiment of the present invention. It is sectional drawing which shows the solid electrolytic capacitor which concerns on embodiment of this invention. It is a perspective view which shows the manufacturing method of the solid electrolytic capacitor which concerns on embodiment of this invention. FIG. 3 is a perspective view showing a continuation of FIG. 2 in the method for manufacturing a solid electrolytic capacitor according to the embodiment of the present invention. FIG. 4 is a perspective view showing a continuation of FIG. 3 in the method for manufacturing the solid electrolytic capacitor according to the embodiment of the present invention. It is sectional drawing which shows the manufacturing method of the solid electrolytic capacitor which concerns on embodiment of this invention. FIG. 7 is a cross-sectional view showing a continuation of FIG. 6 in the method for manufacturing the solid electrolytic capacitor according to the embodiment of the present invention.

  Below, the solid electrolytic capacitor and its manufacturing method which concern on embodiment of this invention are demonstrated. Here, FIG. 1 (A) is a perspective view showing the appearance of the solid electrolytic capacitor 11, FIG. 1 (B) is a plan view showing the appearance of the solid electrolytic capacitor 11, and FIG. 2 is an exploded perspective view of a solid electrolytic capacitor 11. FIG. 2A is a cross-sectional view taken along line XX in FIG. 1B, and FIG. 2B is a cross-sectional view taken along line YY in FIG. FIG. 2C is a cross-sectional view taken along line ZZ in FIG.

  As shown in FIG. 1C, the solid electrolytic capacitor 11 has a first main surface 12, a second main surface 13, and a side surface 14 connecting them, and FIGS. 1B and 1C. As shown in FIG. 1, the valve action metal substrate 1 having the anode lead portion 2 and the cathode layer forming portion 3 separated by the insulating layer 4 and the laminate 9 in which the four valve action metal substrates are stacked. ing.

  The valve action metal substrate 1 has, for example, a foil shape and a flat plate shape, and examples of the material include aluminum, tantalum, niobium, titanium, zirconium, and alloys thereof. The width and thickness are appropriately selected according to the size and capacitance of the solid electrolytic capacitor 11 to be manufactured.

  The constituent material of the insulating layer 4 is, for example, polyphenylsulfone, polyethersulfone, cyanate ester resin, fluororesin (tetrafluoroethylene, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, etc.), low molecular weight polyimide, and their Examples thereof include insulating resins such as derivatives and precursors. Particularly preferred are low molecular weight polyimides, polyethersulfones, fluororesins and their precursors.

  Further, as shown in FIGS. 1B and 1C, the first main surface 12 of the valve metal base 1 has two side surfaces 14 corresponding to both end surfaces in the longitudinal direction of the valve metal base 1. A concave portion 5 is formed so that the portion is exposed.

  Here, the recessed part 5 is depressed with respect to the main surface of the valve action metal substrate 1, and indicates a region where a conductor 8 described later can be disposed.

  Further, as shown in FIGS. 2A, 2B, and 2C, the first main surface 12, the second main surface 13, and the side surface 14 of the valve metal base 1 are made of the valve metal base. A dielectric oxide film 6 made of an oxide is formed.

  Further, as shown in FIGS. 2A and 2B, the four valve metal bases 1 are electrically joined through the joint 10 at the anode lead-out portion 2 and the cathode layer forming portion 3. ing. (In FIG. 1C, the joint 10 is not shown).

  Further, as shown in FIGS. 2A and 2C, a solid electrolyte 7 is formed so as to cover the outer surface of the dielectric oxide film 6 in the cathode layer forming portion 3 of the valve action metal substrate 1. Specifically, the solid electrolyte 7 is formed so as to cover the gaps between the valve action metal substrates 1 in the cathode layer forming part 3, the recesses 5, and the outer surface of the laminate 9.

  Examples of the material of the solid electrolyte 7 include a conductive polymer containing a thiophene compound, a polycyclic sulfide compound, a pyrrole compound, a furan compound, an aniline compound and the like as a repeating unit.

  Further, as shown in FIGS. 1B, 1 C, 2 A, and 2 C, the recess 5 formed in the cathode layer forming portion 3 on the first main surface 12 of the valve action metal substrate 1. Is filled with a conductor 8.

  Further, as shown in FIGS. 1A, 2A, and 2C, the conductor 8 is a recess formed in the cathode layer forming portion 3 on the first main surface 12 of the valve action metal substrate 1. 5 and is formed so as to cover the solid electrolyte 7 formed on the outer surface of the laminate 9.

  The conductor 8 has a higher electrical conductivity than the solid electrolyte 7, and examples thereof include a paste film and a metal plating film containing silver, copper, and nickel.

  In the solid electrolytic capacitor 11 having the above-described structure, the electric charge accumulated in the cathode layer is released using the conductor 8 having a higher conductivity than the solid electrolyte 7 as a medium, so that ESR can be reduced.

  Further, the conductor 8 is formed in the recess 5 formed in the valve action metal base 1, and does not substantially protrude from the first main surface 12 of the valve action metal base 1, in this case, There is no hindrance to downsizing of the solid electrolytic capacitor 11.

  Next, an example of a method for manufacturing the solid electrolytic capacitor 11 will be described. 3 to 5 are perspective views showing a method for manufacturing the solid electrolytic capacitor 11 according to the present invention. 6-7 is sectional drawing which shows the manufacturing method of the solid electrolytic capacitor 11 which concerns on this invention. FIGS. 6A, 6B, and 6C show lines AA in FIG. 3C, lines BB in FIG. 4A, and lines C1-C1 and C2 in FIG. 4B, respectively. It is sectional drawing which follows -C2. 7A, 7B, and 7C are respectively the line DD in FIG. 4C, the line EE in FIG. 5A, and the line FF in FIG. 5C. FIG. Below, it demonstrates based on FIGS. 3-5, and refer FIGS. 6-7 suitably.

  First, as shown in FIG. 3A, a foil-like valve metal substrate 1 having a first main surface 12, a second main surface 13, and a side surface 14 connecting them is prepared.

  Then, a region having an arbitrary length from one end of the long side of the valve metal base 1 and serving as an anode terminal is an anode lead-out portion 2, and a region having an arbitrary length from the other end and serves as a capacity forming portion. The region was defined as the cathode layer forming portion 3. The sizes of the anode lead portion 2 and the cathode layer forming portion 3 may be set as appropriate according to the desired capacitance of the solid electrolytic capacitor.

  Here, it is preferable that the surface in the cathode layer forming portion 3 of the valve action metal substrate 1 is roughened. By doing in this way, the electrostatic capacitance of the solid electrolytic capacitor 11 can be made larger.

  Next, as shown in FIG. 3 (B), the first main surface 12 of the valve metal substrate 1 is exposed to two side surfaces 14 corresponding to both end surfaces in the longitudinal direction of the valve metal substrate 1, and the valve A recess 5 is formed so as to be substantially parallel to the long side of the working metal substrate 1.

  The recess 5 can be formed by pressing, scribing, laser processing or the like, and preferably has a width of 0.5 to 2.5 mm and a depth of 10 to 25 μm.

  Next, as shown in FIG. 3C, a dielectric oxide film 6 is formed on the surfaces of the first main surface 12, the second main surface 13, and the side surface 14 of the valve metal base 1 (FIG. 6). (See (A)).

  Examples of the method of forming the dielectric oxide film 6 include an anodic oxidation method in which the valve metal base 1 is immersed in an electrolytic solution such as phosphoric acid, boric acid, or adipic acid and energized.

  Next, as shown in FIG. 4A, the anode lead portion 2 and the cathode layer forming portion 3 are divided into the first main surface 12, the second main surface 13, and the side surface 14 of the valve metal base 1. For this purpose, a strip-shaped insulating layer 4 is formed (see FIG. 6B).

  The insulating layer 4 is formed by, for example, polyphenylsulfone, polyethersulfone, cyanate ester resin, fluororesin (tetrafluoroethylene, tetrafluoroethylene, tetrafluoroethylene) on the first main surface 12 and second main surface of the valve action metal substrate 1. Fluoroethylene / perfluoroalkyl vinyl ether copolymer, etc.), low molecular weight polyimide, and insulating resins such as derivatives and precursors thereof are used as the first main surface 12 and the second main surface 13 of the valve metal substrate 1. And curing after applying to the side surface 14 in a strip shape.

  Next, as shown in FIG. 4 (B), four valve action metal substrates 1 are stacked, and in a predetermined region of the anode lead portion 2 and the cathode layer forming portion 3 of the valve action metal substrate 1, The stacked body 9 is formed by bonding to each other (see FIG. 6C). Note that the cross-sectional view along line C1 and the cross-sectional view along C2 in FIG. Further, in FIG. 4B, the notation of the joint portion 10 is omitted.

  For joining the valve action metal bases 1, for example, resistance welding or laser welding is performed in a predetermined region to melt the valve action metal bases 1. Thereby, it can carry out by making the molten metals originating from the adjacent valve action metal base | substrate 1 contact directly, integrating by surface tension etc., and solidifying in the state which the molten metal integrated after that.

  Next, after immersing the cathode layer forming region 3 of the valve action metal substrate 1 constituting the laminate 9 in a monomer solution such as a thiophene compound, a polycyclic sulfide compound, a pyrrole compound, a furan compound, or an aniline compound, The operation of immersing in the mixed solution of the dopant is repeated. By this operation, as shown in FIG. 4 (C), the surface of the dielectric oxide film 6 in the cathode layer forming portion 3 in the valve action metal substrate 1 constituting the laminate 9 is coated (that is, in the cathode layer forming portion 3). A semi-cured solid electrolyte 7H is formed so as to fill the gaps between the valve action metal bases 1 and the recesses 5 and cover the outer surface of the laminate 9). (See FIG. 7A).

  Here, when the valve action metal base | substrate with which the surface is roughened is used, the clearance gap between the valve action metal base | substrates 1 is naturally formed only by overlapping the valve action metal base | substrates 1 mutually.

  Next, as shown in FIG. 5A, a part of the semi-cured solid electrolyte 7H filled in the recess 5 is placed in the recess 5 in order to secure a region in which the conductor 8 described later is disposed. It is removed (see FIG. 7B). Here, the semi-cured solid electrolyte 7 </ b> H filled in the recess 5 may be removed so that the solid electrolyte 7 to be described later has a volume of 20 to 70% with respect to the volume of the recess 5 in the recess 5. preferable.

  As a method for removing a part of the semi-cured solid electrolyte 7H, for example, a fluid (cleaning liquid, non-cleaning liquid) is introduced from the end of the recessed portion 5 exposed on the side surface 14 on the cathode layer forming portion 3 side of the valve action metal substrate 1. Active gas etc.) 14 is injected to extrude the semi-cured solid electrolyte 7H. At this time, if the insulating layer 4 is formed so that the thickness of the insulating layer 4 is equal to or less than the thickness of the semi-cured solid electrolyte 7H remaining in the cathode layer forming portion 3, the semi-cured solid electrolyte 7H extruded by the fluid is used. Can be discharged to the outside of the laminate 9 from the end of the recess 5 exposed at the side surface 14 of the valve action metal base 1 on the anode lead-out side.

  In addition, after removing a part of the semi-cured solid electrolyte 7H so that the semi-cured solid electrolyte 7H does not remain in the anode drawn portion of the valve action metal substrate 1, the anode draw-out portion of the valve action metal substrate 1 is removed. It is preferable to wash.

  Next, the semi-cured solid electrolyte 7H is dried to form the solid electrolyte 7 as shown in FIG.

  Next, as shown in FIG. 5C, the conductor 8 is formed in the recess 5 so as to cover the solid electrolyte 7 formed on the outer surface of the laminate 9 (FIG. 7C). reference). The arrangement of the conductor 8 in the recess 5 and the formation on the outer surface of the laminate 9 are performed by immersing the region of the laminate 9 where the solid electrolyte 11 is formed in a paste solution containing silver, copper, nickel or the like. Thus, the paste solution can be permeated into the recess 5 and applied to the outside of the laminate, and then the paste solution is dried.

  As described above, after forming the laminated body, the manufacturing process can be made more efficient by collectively forming the solid electrolyte and arranging the conductor on the valve metal substrate constituting the laminated body.

  In addition, since the conductor 8 functions as a cathode of the solid electrolytic capacitor 11, it is necessary to prevent the conductor 8 from being formed on the anode lead portion 2 of the valve metal base 1.

  The solid electrolytic capacitor 11 is manufactured through the above steps.

  After the above steps, the dielectric oxide film formed on the anode lead portion of the valve metal base 1 is removed, and then an anode external terminal is connected to the conductor 8 formed on the outer surface of the laminate 9. The laminated body 9 may be sealed with an insulating resin such as an epoxy resin in a state where the cathode external terminal is connected and then the anode external terminal and a part of the cathode external terminal are exposed.

  The solid electrolytic capacitor and the manufacturing method thereof shown in the above embodiment are merely examples, and other various modifications may be made within the scope of the present invention.

  A plurality of recesses may be formed on the first main surface of the valve metal substrate, or may be formed on both the first main surface and the second main surface.

  By increasing the number of recessed portions and the area of the exposed portion on the side surface of the cathode layer forming portion as long as the rigidity of the valve metal base is not hindered, the amount of the conductor occupying the laminate and the conductor lead-out portion can be reduced. The ESR can be further reduced.

  Further, the formation position of the recesses on the first main surface and the second main surface of the valve action metal substrate is not particularly limited as long as one end is exposed on the side surface of the cathode layer formation portion of the valve action metal substrate. It is not limited to the positional relationship substantially parallel to the long side of the valve action metal substrate as shown in the embodiment.

  Moreover, the shape of the recessed part projected from the main surface of the valve action metal base | substrate is not limited to what is a rectangle like the said embodiment, A shape including a curve part may be sufficient.

  Further, the cross-sectional shape of the recess is not particularly limited as long as the conductor can be disposed.

  Further, it is not necessary that all the valve action metal bases constituting the laminate are formed with recesses, and the valve action metal base with recesses formed and the valve action metal base with no recesses are used in combination. You may make a body.

  In addition, the number of valve action metal bases constituting the laminate and the composition ratio of the valve action metal bases in which recesses are formed and the valve action metal bases in which no recesses are formed depend on the characteristics required for the solid electrolytic capacitor. It can be set appropriately.

  The joint position and the number of joints between the valve action metal bases when producing the laminated body are not particularly limited to the joint form of the above embodiment, and for example, provided only in one of the anode lead part and the cathode layer forming part. Anyway.

  In addition, the dielectric oxide film may be formed after the laminate is formed. By doing in this way, when joining valve action metal bases, since a dielectric oxide film is not interposed, between valve action metal bases can be joined more stably.

The solid electrolyte may be formed by electrolytic polymerization or a method of applying a conductive polymer compound solution. In the case of forming a solid electrolyte by electrolytic polymerization, since the formation can be stopped at a stage where the solid electrolyte in the recess is formed to a desired volume, the semi-cured solid electrolyte in the recess shown in the above embodiment The operation of removing a part of the can be omitted.

  Next, examples according to the present invention will be described. This example is in accordance with the embodiment of the present invention, and will be described with reference to FIGS.

  Four aluminum foils having a width of 3.5 mm, a length of 13 mm, and a thickness of 110 μm were prepared. And the area | region 6.2 mm from the one end of the long side of aluminum foil was defined as the anode extraction part, and the area | region 6 mm from the other end was defined as the cathode layer formation part.

  Next, as viewed from one main surface of the aluminum foil, a recess having a width of 1 mm and a depth of 20 μm centering on a line segment that bisects the short side corresponds to both end surfaces in the longitudinal direction of the aluminum foil. It formed by laser processing so that it might be exposed to a side surface (refer FIG. 2 (B)).

  Next, the aluminum foil is immersed in an aqueous solution of ammonium adipate, the aluminum foil is used as the positive electrode, the counter electrode installed in the ammonium adipate solution is used as the negative electrode, and a voltage of 3.5 V is applied to oxidize the surface of the aluminum foil. An aluminum film was formed.

  Next, a polyimide resin was applied to both the main surface, the concave portion, and the side surface of the aluminum foil with a width of 0.8 mm centering on the position of 6.4 mm from the short side in the cathode layer forming portion of the aluminum foil. And the insulating layer which consists of a polyimide resin hardening body was formed by making it dry at 180 degreeC for 1 hour. (See FIG. 3A).

  Next, four aluminum foils each having a recess, an aluminum oxide film, and an insulating layer were stacked to prepare a laminate.

  Then, the positions of 0.5 mm and 3.0 mm from the long side are joined by resistance welding on the line segment that bisects the long side of the anode lead portion and the cathode layer forming portion as viewed from the main surface of the aluminum foil. Thus, a laminate was produced.

  Next, an operation of immersing the cathode layer forming portion in the aluminum foil constituting the laminate in an isopropanol solution containing 3,4-ethylenedioxythiophene and then immersing in a mixed solution of ammonium persulfate and sodium anthraquinone disulfonate. Repeat 20 times. By this operation, polyethylenedioxythiophene in a semi-cured state is formed in the cathode layer forming part in the aluminum foil constituting the laminate.

  Next, air was sprayed on the semi-cured polyethylenedioxythiophene formed so as to fill the recess, and the later-described polyethylenedioxythiophene was removed so that 20% of the volume of the recess remained.

  Next, the laminate coated with the semi-cured polyethylene dioxythiophene was dried in an oven to advance the polymerization reaction, thereby forming polyethylene dioxythiophene.

  Next, the region in which the polyethylene dioxythiophene is formed in the laminate is dipped in a copper paste solution and dried, so that the copper paste film is placed in the recess and the copper is coated to cover the outer surface of the laminate. A paste film was formed.

Next, the anode lead frame was connected to the anode lead portion of the aluminum foil, and the cathode lead frame was connected to the copper paste film formed on the outer surface of the laminate. Thereafter, a part of the lead frame was exposed and sealed with an epoxy resin so as to have an outer dimension of 7.3 × 4.3 × 1.9 mm, thereby producing a solid electrolytic capacitor. Table 1 shows the results of measuring the volume, capacitance, volume capacity efficiency, and ESR of this solid electrolytic capacitor.
(Comparative Example 1)
A solid electrolytic capacitor was produced in the same manner as in Example 1 except that an aluminum foil having no recess was used and no copper paste film was provided between the aluminum foils constituting the laminate. Table 1 shows the results of measuring the volume, capacitance, volume capacity efficiency, and ESR of this solid electrolytic capacitor.
(Comparative Example 2)
An aluminum foil having no recesses was prepared, and an aluminum oxide film was formed on the surface of the aluminum foil. And after forming polyethylenedioxythiophene, a carbon containing layer, and a silver containing layer in the cathode layer formation part of aluminum foil, the anode drawer parts of four aluminum foils were joined, and the laminated body was produced.

  Next, a lead frame is connected to the silver-containing layer formed in the anode lead portion of the aluminum foil and the cathode layer forming portion of the aluminum foil, and then a part of the lead frame is exposed, and the outer dimensions are 7.3 × 4. A solid electrolytic capacitor was produced by sealing with an epoxy resin so as to be 3 × 1.9 mm.

  In addition, the carbon-containing layer and the silver-containing layer are formed on the cathode layer forming portion of the aluminum foil by immersing the aluminum foil in which the aluminum oxide film and the polyethylene dioxythiophene are formed in the order of the carbon paste solution and the silver paste solution. This was done by drying. Other configurations were the same as in Example 1.

  Table 1 shows the results of measuring the volume, capacitance, volume capacity efficiency, and ESR of this solid electrolytic capacitor.

  As shown in Table 1, the solid electrolytic capacitor of the example according to the present invention can reduce ESR with respect to the solid electrolytic capacitor of Comparative Example 1, and has a volume capacity efficiency higher than that of the solid electrolytic capacitor of Comparative Example 2. It was possible to improve or downsize.

DESCRIPTION OF SYMBOLS 1 Valve action metal base | substrate 2 Anode lead-out part 3 Cathode layer formation part 4 Insulation layer 5 Recessed part 6 Dielectric oxide film 7 Solid electrolyte 7H Semi-hardened solid electrolyte 8 Conductor 9 Laminated body 10 Junction part 11 Solid electrolytic capacitor 12 1st Main surface 13 Second main surface 14 Side surface

Claims (2)

A valve metal substrate having a first main surface, a second main surface, and a side surface connecting them, and having an anode lead portion and a cathode layer forming portion;
A laminate in which a plurality of the valve action metal bases are stacked and joined to each other at the anode lead part and / or the cathode layer forming part,
A dielectric oxide film formed on at least a first main surface, a second main surface, and a side surface of at least the cathode layer forming portion of the valve action metal substrate;
A solid electrolytic capacitor comprising a solid electrolyte formed so as to cover a dielectric oxide film in a cathode layer forming portion of the valve action metal substrate,
The first main surface and / or the second main surface of at least one or more valve metal substrates constituting the laminate includes at least a cathode layer forming portion, and at least one end thereof is in the cathode layer forming portion. A recess is formed to be exposed on the side,
A solid electrolytic capacitor, wherein a conductor is disposed in a recess in the cathode layer forming portion of the valve metal substrate. Preparing a valve metal substrate having a first main surface, a second main surface, and a side surface connecting them, and having an anode lead portion and a cathode layer forming portion;
A stack forming step of stacking a plurality of the valve action metal bases and bonding them together at an anode lead part and / or a cathode layer forming part,
The laminated body forming step includes at least one cathode layer forming region on at least one of the first main surface and / or the second main surface of at least one valve action metal substrate constituting the laminated body. A recess forming step of forming a recess so as to be exposed on the side surface of the cathode layer forming portion of the valve action metal substrate;
A dielectric film forming step of forming a dielectric oxide film on at least the first main surface, the second main surface, and the side surface in the cathode layer forming portion of the valve metal substrate constituting the laminate,
After the laminate formation step, a solid electrolyte formation step of forming a solid electrolyte so as to cover a dielectric oxide film in the cathode layer formation portion of the valve action metal substrate,
A method for producing a solid electrolytic capacitor, comprising a conductor arranging step of arranging a conductor in a recess in a cathode layer forming portion of the valve metal substrate after the solid electrolyte forming step.

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