JP2018142667A - Electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrolytic capacitor that is configured to suppress anode wire from falling down during welding.SOLUTION: In the electrolytic capacitor in which an anode lead frame 131 is melted so that the anode lead frame is welded to anode wire 2, the anode lead frame has a notch N, where an end surface of the notch is formed of a first side part NS1 extending from a first notch end part at one side of a first side toward a second side opposing to the first side and a second side part NS2 extending from a second notch end part at the other side of the first side toward the second side. The anode wire is welded to the anode lead frame at the first side part and at the second side part. A sharp angle θwformed by a straight line LC drawn in a horizontal direction passing through a center C of a cross section of the anode wire and a straight line Lwconnecting a first weld vestige on the first side part to the center C and a sharp angle θwformed by the straight line LC and a straight line Lwconnecting a second weld vestige on the second side part to the center C both are larger than 0° and are equal to 45° or less.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an electrolytic capacitor, and more particularly to an electrolytic capacitor in which an anode wire and an anode lead frame are welded.

  Electrolytic capacitors have low equivalent series resistance (ESR) and excellent frequency characteristics, and are therefore mounted on various electronic devices. An electrolytic capacitor usually includes a capacitor element having an anode part and a cathode part, an anode lead terminal electrically connected to the anode part, a cathode lead terminal electrically connected to the cathode part, a part of the anode lead terminal and And an exterior body that covers the capacitor element so that a part of the cathode lead terminal is exposed to the outside. At the exposed portions of the anode lead terminal and the cathode lead terminal, the electrolytic capacitor is connected to the substrate of the electronic device. The anode part has an anode body and an anode wire extending from the anode body. The anode wire is planted from almost the center of one surface of the anode body. At this time, an anode lead terminal having a plate-like member called an anode lead frame is used, and the anode lead terminal and the anode wire are electrically connected by joining the anode lead frame and the anode wire. (Patent Document 1).

JP 2011-187986 A

  In Patent Document 1, a notch is provided in the anode lead frame, and after fitting the anode wire into the notch, the lower portion of the anode wire and the anode lead frame are welded. In this case, when the anode lead frame is melted and the anode wire is joined, the positional deviation (sag) of the anode wire in the vertical direction (vertical direction) increases. This is because the anode lead frame is deformed by melting. In particular, in the case of resistance welding, since energization is performed while applying pressure, the deformation of the anode lead frame is likely to increase, and the drop of the anode wire also increases.

  When the anode wire falls, the capacitor element tilts with the anode wire being planted downward. Usually, the joining of the anode lead frame and the anode wire is performed in a state where the cathode lead terminal is brought into contact with the cathode portion via a conductive adhesive. Therefore, with the inclination of the capacitor element, the cathode lead terminal and the capacitor element are separated from each other, or the conductive adhesive interposed therebetween moves, so that the adhesiveness becomes unstable. Thereby, connection reliability may fall. Further, if the conductive adhesive protrudes between the cathode lead terminal and the capacitor element, the device may be contaminated.

A first aspect of the present invention includes a capacitor element including an anode part and a cathode part, an anode lead terminal electrically connected to the anode part, a cathode lead terminal electrically connected to the cathode part, and the capacitor An exterior body that covers the element and exposes at least a part of each of the anode lead terminal and the cathode lead terminal, and the anode portion includes an anode body and an anode wire extending from the anode body And the anode lead terminal has a flat plate shape and has an anode lead frame formed with a cutout part of a first side of the anode lead terminal. In the state where the surface and the extending direction of the anode wire intersect each other, the end surface of the notch of the anode lead frame is melted and welded to the anode wire, whereby the anode portion and the anode lead A terminal is electrically connected, and an end surface of the notch extends from a first notch end portion of the first side toward a second side opposite to the first side. And a second side portion extending from the other second notched end portion of the first side toward the second side, the anode wire and the The anode lead frame is welded at the first side portion and the second side portion, and the normal direction of the main surface of the anode lead frame is in a state where the second side is in contact with a horizontal plane. When the cross section of the anode wire is viewed from the straight line Lc drawn in the horizontal direction passing through the center C of the cross section of the anode wire, the straight line connecting the first welding mark on the first side portion and the center C An acute angle θw ₁ formed with Lw ₁ and the straight line Lc are on the second side portion. The present invention relates to an electrolytic capacitor in which an acute angle θw ₂ formed with a straight line Lw ₂ connecting the second welding mark and the center C is greater than 0 ° and equal to or less than 45 °.

  According to the present invention, since the drop of the anode wire during welding is suppressed, a high quality electrolytic capacitor can be stably obtained.

It is a cross-sectional schematic diagram of the electrolytic capacitor which concerns on one Embodiment of this invention. It is the front schematic diagram (a) which looked at the anode lead frame from the normal line direction of the main surface, and the cross-sectional schematic diagram (b) which looked at the anode lead frame and anode wire after welding from the same direction. It is a cross-sectional schematic diagram which shows the anode lead frame which concerns on one Embodiment of this invention, and the anode wire welded to this. It is a cross-sectional schematic diagram which shows the anode lead frame concerning other embodiment of this invention, and the anode wire welded to this. It is a cross-sectional schematic diagram which shows the anode lead frame concerning further another embodiment of this invention, and the anode wire welded to this. It is the cross-sectional schematic diagram (a) which shows the anode lead frame and anode wire before welding which concern on one Embodiment of this invention, and the cross-sectional schematic diagram (b) which shows the anode lead frame and anode wire (a) after welding.

  An electrolytic capacitor according to an embodiment of the present invention will be described with reference to FIG. 1 by taking as an example a case where a solid electrolyte layer is provided as an electrolyte, but is not limited thereto. FIG. 1 is a schematic cross-sectional view of an electrolytic capacitor 20 according to this embodiment.

<Electrolytic capacitor>
The electrolytic capacitor 20 includes a capacitor element 10 having an anode portion 6 and a cathode portion 7, an exterior body 11 that seals the capacitor element 10, an electrical connection with the anode portion 6, and a part from the exterior body 11. An exposed anode lead terminal 13 and a cathode lead terminal 14 electrically connected to the cathode portion 7 and partially exposed from the exterior body 11 are provided. The anode unit 6 includes an anode body 1 including a dielectric layer 3 and an anode wire 2. The cathode portion 7 includes a solid electrolyte layer 4 formed on the dielectric layer 3 and a cathode layer 5 that covers the surface of the solid electrolyte layer 4.

<Anode section>
The anode portion 6 includes an anode body 1 and an anode wire 2 that extends from one surface of the anode body 1 and is electrically connected to the anode lead terminal 13.
The anode body 1 is, for example, a rectangular parallelepiped porous sintered body obtained by sintering metal particles. As the metal particles, valve action metal particles such as titanium (Ti), tantalum (Ta), and niobium (Nb) are used. One type or two or more types of metal particles are used for the anode body 1. The metal particles may be an alloy composed of two or more metals. For example, an alloy containing a valve action metal and silicon, vanadium, boron, or the like can be used. A compound containing a valve metal and a typical element such as nitrogen may be used. The alloy of the valve action metal preferably contains the valve action metal as a main component and contains 50 atom% or more of the valve action metal.

  The anode wire 2 is made of, for example, a conductive material. The material of the anode wire 2 is not specifically limited, For example, copper, aluminum, aluminum alloy etc. other than the said valve action metal are mentioned. The material of the anode wire 2 is selected so that the anode lead frame 131 melts during welding in consideration of the material of the anode lead terminal 13 (anode lead frame 131 described later) and the welding method. The anode wire 2 includes a first portion 2 a embedded from one surface of the anode body 1 into the anode body 1 and a second portion 2 b extending from the one surface of the anode body 1. The cross-sectional shape of the anode wire 2 is not particularly limited, and is a circular shape or a shape obtained by crushing a circular shape (a shape consisting of straight lines parallel to each other and two curves connecting the ends of these straight lines. Hereinafter, referred to as a track shape. .), Oval, rectangular, polygonal and the like. Among these, the track shape is preferable in that rolling is suppressed during positioning with the anode lead frame 131 and positioning is easy. The diameter of the anode wire 2 (long diameter in the case of a track shape and an elliptical shape) is not particularly limited, but is, for example, 0.1 mm to 1.0 mm.

  The anode part 6 is produced, for example, by pressing and sintering metal particles into a rectangular parallelepiped shape with the first part 2a embedded in the powder of the metal particles. Thereby, it pulls out so that the 2nd part 2b of the anode wire 2 may be planted from one surface of the anode body 1. FIG. The second portion 2b is joined to the anode lead frame 131 by welding (resistance welding, laser welding, etc.). Thereby, the anode wire 2 and the anode lead terminal 13 are electrically connected. Although the welding method is not particularly limited, here, in consideration of both materials, a method of welding by melting the anode lead frame 131 is selected. For example, when the anode wire 2 is tantalum and the anode lead frame 131 is copper, the anode lead frame 131 is melted when resistance welding is employed.

  A dielectric layer 3 is formed on the surface of the anode body 1. The dielectric layer 3 is made of, for example, a metal oxide. As a method for forming a layer containing a metal oxide on the surface of the anode body 1, for example, a method of anodic oxidation of the surface of the anode body 1 by immersing the anode body 1 in a chemical conversion solution, or a method in which the anode body 1 contains oxygen The method of heating in an atmosphere is mentioned. The dielectric layer 3 is not limited to the layer containing the metal oxide, and may have an insulating property.

<Cathode part>
The cathode portion 7 includes a solid electrolyte layer 4 formed on the dielectric layer 3 and a cathode layer 5 that covers the solid electrolyte layer 4.
The solid electrolyte layer 4 only needs to be formed so as to cover at least a part of the dielectric layer 3. For example, a manganese compound or a conductive polymer is used for the solid electrolyte layer 4. Examples of the conductive polymer include polypyrrole, polythiophene, polyfuran, polyaniline, polyacetylene, polyphenylene, polyparaphenylene vinylene, polyacene, polythiophene vinylene, polyfluorene, polyvinyl carbazole, polyvinyl phenol, polypyridine, and derivatives of these polymers. Can be mentioned. These may be used alone or in combination of two or more. The conductive polymer may be a copolymer of two or more monomers. Among these, polythiophene, polyaniline, polypyrrole, and the like are preferable in terms of excellent conductivity. Of these, polypyrrole is preferred because of its excellent water repellency.

  The solid electrolyte layer 4 containing the conductive polymer is formed, for example, by polymerizing a raw material monomer on the dielectric layer 3. Alternatively, it is formed by applying a liquid containing the conductive polymer to the dielectric layer 3. The solid electrolyte layer 4 is composed of one or more solid electrolyte layers. When the solid electrolyte layer 4 is composed of two or more layers, the composition and formation method (polymerization method) of the conductive polymer used in each layer may be different.

  In the present specification, polypyrrole, polythiophene, polyfuran, polyaniline and the like mean polymers having a basic skeleton of polypyrrole, polythiophene, polyfuran, polyaniline and the like, respectively. Accordingly, polypyrrole, polythiophene, polyfuran, polyaniline and the like can also include respective derivatives. For example, polythiophene includes poly (3,4-ethylenedioxythiophene) and the like.

  In order to improve the conductivity of the conductive polymer, various dopants may be added to the polymerization liquid, the conductive polymer solution or the dispersion liquid for forming the conductive polymer. The dopant is not particularly limited. 2,7-naphthalenedisulfonic acid, 2-methyl-5-isopropylbenzenesulfonic acid, 4-octylbenzenesulfonic acid, 4-nitrotoluene-2-sulfonic acid, m-nitrobenzenesulfonic acid, n-octylsulfonic acid, n-butane Sulfonic acid, n-hexanesulfonic acid, o-nitrobenzenesulfonic acid, p-ethylbenzenesulfonic acid, trifluoromethanesulfonic acid, hydroxybenzenesulfonic acid, butylnaphthalenesulfonic acid, benzenesulfonic acid, polystyrenesulfonic acid, polyvinylsulfone Acid, methanesulfonic acid, and, derivatives thereof, and the like. Examples of the derivatives include metal salts such as lithium salt, potassium salt and sodium salt, ammonium salts such as methylammonium salt, dimethylammonium salt and trimethylammonium salt, piperidinium salt, pyrrolidinium salt and pyrrolinium salt.

  When the conductive polymer is dispersed in a dispersion medium in the form of particles, the average particle diameter D50 of the particles is preferably 0.01 μm to 0.5 μm, for example. If the average particle diameter D50 of the particles is within this range, the particles easily penetrate into the anode body 1.

  The cathode layer 5 includes, for example, a carbon layer 5a formed so as to cover the solid electrolyte layer 4, and a metal paste layer 5b formed on the surface of the carbon layer 5a. The carbon layer 5a includes a conductive carbon material such as graphite and a resin. The metal paste layer 5b includes, for example, metal particles (for example, silver) and a resin. The configuration of the cathode layer 5 is not limited to this configuration. The structure of the cathode layer 5 should just be a structure which has a current collection function.

<Anode lead terminal>
The anode lead terminal 13 has a function of electrically connecting the electronic component on which the electrolytic capacitor 20 is mounted and the anode portion 6. The anode lead terminal 13 includes a plate-like anode lead frame 131 and an anode exposed portion 132 exposed from the exterior body 11. The anode lead frame 131 and the anode exposed portion 132 may be formed integrally or may be separate. If they are separate, they are electrically connected. The anode lead frame 131 is sealed together with the capacitor element 10 by the exterior body 11.

  Hereinafter, the anode lead frame 131 will be described in detail with reference to FIGS. 2 (a) and 2 (b). FIG. 2A is a schematic front view of the anode lead frame 131 viewed from the normal direction of the main surface, and FIG. 2B shows the anode lead frame 131 and the anode wire 2 in the same direction after welding. It is the schematic cross section seen from. FIG. 2B shows the anode wire 2 by its cross section, but hatching is omitted for convenience. The same applies to FIGS. 3A to 3C and FIG. In the illustrated example, the anode lead frame 131 is erected with the second side 1312 in contact with the horizontal plane. Hereinafter, the vertical direction or the horizontal direction refers to a direction when the anode lead frame 131 is viewed in a standing state as in the illustrated example.

  The anode lead frame 131 has a cutout N formed by cutting out a part of the first side 1311. Such an anode lead frame 131 is obtained, for example, by punching a plate-like conductor (conductor plate) into a predetermined shape. During the welding, the second portion 2b of the anode wire 2 is placed on the notch N.

  In the present embodiment, the anode lead frame 131 and the anode wire 2 are melted in a state where the main surface of the anode lead frame 131 and the extending direction of the anode wire 2 intersect with each other, The anode lead terminal 13 and the anode wire 2 are joined. However, in order to weld the anode wire 2 while supporting both sides of the anode wire 2 by contacting the anode wire 2 to two side portions NS1 and NS2 of the end face of the notch N or two corners formed by the notch N. The positional deviation (sag) in the vertical direction of the anode wire 2 is reduced. Furthermore, since the anode lead frame 131 and the anode wire 2 are brought into contact with each other at two points, the welding area per place necessary for connection is smaller than that in the case where welding is carried out with only one place being brought into contact. Therefore, the amount of melting of the anode lead frame 131 per place is reduced, and the drop of the anode wire 2 is further suppressed.

  Conventionally, since the anode wire having a circular cross section has a small contact area with the anode lead frame, it is necessary to increase the melting amount of the anode lead frame. Therefore, when a circular anode wire is used, the amount of sagging generally tends to increase. However, according to the present embodiment, the amount of sagging is suppressed even when a circular anode wire is used.

  The cutout N cuts out a part of the first side 1311. The end face of the notch N extends from the notch starting point (first notch end portion 1311A) formed in the first side 1311 toward the second side 1312 facing the first side 1311. 1 side part NS1, and 2nd side part NS2 extended toward the 2nd edge | side 1312 from the end point (2nd notch edge part 1311B) of the notch formed in the 1st edge | side 1311. ing. In the illustrated example, the end face of the notch N further has an end different from the first notch end 1311A of the first side part NS1 and an end different from the second notch end 1311B of the second side part NS2. The bottom part NB which connects a part is provided.

The shape of the notch N is not particularly limited as long as the anode wire 2 and the anode lead frame 131 are welded at two points of the first side part NS1 and the second side part NS2. In particular, when the cross section of the anode wire 2 after welding is viewed from the normal direction of one main surface of the anode lead frame 131, a straight line Lc drawn in the horizontal direction passing through the center C of the cross section of the anode wire 2 is An acute angle (hereinafter referred to as a welding angle θw ₁ ) formed with a straight line Lw ₁ connecting the welding mark W1 on the one side part NS1 and the center C, and a straight line Lc are the second welding mark W2 on the second side part NS2. The shape is such that the acute angle (hereinafter referred to as the welding angle θw ₂ ) formed by the straight line Lw ₂ connecting the center C and the center C is greater than 0 ° and 45 ° or less. Thereby, the drop of the anode wire 2 becomes small. The welding angle θw ₁ and the welding angle θw ₂ are more preferably 15 ° or more and 30 ° or less. The straight line Lw ₁ and the straight line Lw ₂ are straight lines formed by connecting the center of each welding mark and the center C of the anode wire 2.

In such a notch N, for example, the length of a straight line Ln connecting the first notch end portion 1311A and the second notch end portion 1311B before welding (hereinafter referred to as notch width Dn) is an anode. maximum length in the direction along the straight line Ln of the wire 2 (hereinafter, referred to as the first diameter D2 _H.) is shaped shorter than. As a result, the anode wire 2 is welded to the anode lead frame 131 at two points of the first side part NS1 and the second side part NS2, not the bottom part NB of the notch N. Therefore, since the anode wire 2 does not fall from the bottom part NB to the second side 1312 side during welding, the amount of fall of the anode wire 2 is further suppressed. The proportion of the notch width Dn with respect to the first diameter _{D2 H: (Dn / D2 H} ) × 100% is preferably 50-90%, more preferably 60-80%.

The notch N preferably has a tapered shape that narrows toward the second side 1312. That is, it is preferable that the distance between the first side portion NS1 and the second side portion NS2 decreases toward the second side 1312. This is because the drop of the anode wire 2 is more easily suppressed. Among them, an acute angle formed between the vertical direction and the first side portion NS1 (hereinafter, referred to as a first taper angle [theta] t _1.), And the vertical direction at an acute angle formed between the second side portion NS2 (hereinafter, second taper angle θt ₂ ) is greater than 0 °, preferably 60 ° or less, and more preferably 45 ° or less. The first taper angle θt ₁ may be calculated by measuring the angle formed by the bottom portion NB and the first side portion NS1 and subtracting 90 ° from this angle. The same applies to the second taper angle [theta] t _2.

In the illustrated example, the end surface of the notch N includes the bottom portion NB, but is not limited thereto. The first side part NS1 and the second side part NS2 may intersect to form a V-shape. Moreover, although the bottom part NB in the example of illustration is linear, it is not limited to this. The bottom part NB may have a curved part. In order to control the amount of sagging caused by welding of the anode wire 2, the bottom portion NB may include a protrusion or a step that can support the anode wire 2 after welding. If the bottom portion NB has a rectilinear or curved portion, the width of the bottom portion NB is not particularly limited, considering the position of the first diameter D2 _H and welding of the anode wire 2, it may be set as appropriate.

The welding position can be adjusted by Dn / D2 _H , the first taper angle θt ₁ , and the second taper angle θt ₂ . An example is shown in FIGS. 3A-3C. In FIG 3A~ Figure 3C, the diameter D2 _H anode wires 2 are the same. 3A to 3C are schematic cross-sectional views showing the anode lead frame and the anode wire welded thereto according to the present embodiment, respectively.

The notch width Dn of the anode lead frame 131A of FIG. 3A and the anode lead frame 131B of FIG. 3B is the same. On the other hand, the first taper angle θt _1B and the second taper angle θt _2B of the anode lead frame 131B are larger than the first taper angle θt _1A and the second taper angle θt _2A of the anode lead frame 131A. Therefore, in the case of FIG. 3B, the position of the first welding mark W1 _B and the second welding mark W2 _B is shifted to the bottom portion NB side of the first welding mark W1 _A and the second welding marks W2 _A in Figure 3A . In other words, the welding angle θw ₁ and the welding angle θw ₂ in FIG. 3B are larger.

The first taper angle [theta] t ₁ and the second taper angle [theta] t ₂ of the anode lead frame 131C of the anode lead frame 131A and 3C in Figure 3A is the same. On the other hand, the notch width Dn _C of the anode lead frame 131C is smaller than the notch width Dn _A of the anode lead frame 131A. That, Dn / D2 _H in FIG. 3C is smaller. Again, the position of the first welding mark W1 _C and the second welding mark W2 _C in FIG. 3C is shifted to the bottom portion NB side of FIG. 3A, the welding angle .theta.w ₁ and the welding angle .theta.w ₂ in Figure 3C , Bigger.

  In the illustrated example, the welded anode wire 2 and the bottom portion NB of the notch N are in contact with each other. However, the present invention is not limited to this, and the anode wire 2 and the bottom portion NB may not be in contact with each other. This is because the welded anode wire 2 is joined and supported by the two side portions NS1 and NS2. However, it is preferable that the anode wire 2 and the bottom portion NB are in contact with each other after welding because the amount of sagging due to welding of the anode wire 2 can be easily controlled.

The depth of the notch N is not particularly limited. When the anode wire 2 and the bottom part NB are brought into contact with each other after welding, the depth Dnd of the notch N (see FIG. 2A) is the diameter of the anode wire 2 in the vertical direction (second diameter D2 _V ). Is preferably 50% or less. Thereby, the amount of dropping of the anode wire 2 is reduced, and the position of the anode wire 2 after welding is easily controlled. In this case, the center C of the anode wire 2 after welding is located on the side opposite to the second side 1312 with respect to the straight line Ln. Facilitate positioning, also, in that the rolling of the anode wire 2 is suppressed, the first diameter D2 _H anode wires 2 is preferably larger than the second diameter D2 _V.

The depth Dnd of the notch N is the length of a straight line drawn in the vertical direction from the center of the straight line Ln to the bottom portion NB. The second diameter D2 _V of the anode wire 2 is vertical from the center C to the outer edge of the anode wire 2 when the section of the anode wire 2 after welding is viewed from the normal direction of one main surface of the anode lead frame 131. The length of a straight line drawn in the direction.

<Cathode lead terminal>
The cathode lead terminal 14 is electrically connected to the cathode portion 7. The cathode lead terminal 14 is not particularly limited as long as it is made of a conductive material (conductor). The shape is not particularly limited, and is, for example, a flat plate shape. The thickness of the cathode lead terminal 14 is, for example, 25 to 100 μm. The cathode lead terminal 14 may be electrically connected to the cathode portion 7 via a conductive adhesive (not shown).

<Exterior body>
The outer package 11 is provided to electrically insulate the anode lead terminal 13 and the cathode lead terminal 14 from each other and is made of an insulating material. The exterior body 11 contains the hardened | cured material of a thermosetting resin, for example. Examples of the thermosetting resin include epoxy resin, phenol resin, silicone resin, melamine resin, urea resin, alkyd resin, polyurethane, polyimide, unsaturated polyester, and the like.

  The exterior body 11 is formed by, for example, a transfer molding method or a compression molding method in which the thermosetting resin and the capacitor element 10 to which the anode lead terminal 13 and the cathode lead terminal 14 are connected are accommodated in a mold. The At this time, the capacitor element 10 is covered with the exterior body 11 so that the anode lead terminal 13 and the cathode lead terminal 14 have exposed portions exposed from the exterior body 11, respectively. The external shape of the exterior body 11 is a rectangular parallelepiped, for example. The exposed portion of the anode lead terminal 13 and the exposed portion of the cathode lead terminal 14 are disposed on the same surface of the outer package 11 that is a rectangular parallelepiped.

An example of the method for manufacturing the electrolytic capacitor according to this embodiment will be described.
≪Method for manufacturing electrolytic capacitor≫
(1) Step of producing anode part The valve action metal particles and the anode wire 2 are put in a mold so that the first portion 2a is embedded in the valve action metal particles, and after pressure forming, sintered in vacuum. Thus, the anode portion 6 in which the first portion 2a is embedded from one surface of the porous sintered body is produced. The pressure at the time of pressure molding is not specifically limited, For example, it is about 10-100N. If necessary, the valve action metal particles may be mixed with a binder such as polyacrylic carbonate.

(2) Step of forming dielectric layer on anode body Dielectric layer 3 is formed on anode body 1. Specifically, the anode body 1 is immersed in a chemical conversion tank filled with an electrolytic aqueous solution (for example, phosphoric acid aqueous solution), and the second portion 2b of the anode wire 2 is connected to the anode body of the chemical conversion tank, thereby anodizing. By performing the above, the dielectric layer 3 made of an oxide film of the valve metal can be formed on the surface of the anode body 1. The electrolytic aqueous solution is not limited to a phosphoric acid aqueous solution, and nitric acid, acetic acid, sulfuric acid, and the like can be used.

(3) Formation process of solid electrolyte layer In this embodiment, the formation process of the solid electrolyte layer 4 containing a conductive polymer is demonstrated.
The solid electrolyte layer 4 containing a conductive polymer is, for example, a method of impregnating a monomer or oligomer into the anode body 1 on which the dielectric layer 3 is formed, and then polymerizing the monomer or oligomer by chemical polymerization or electrolytic polymerization. Alternatively, the anode body 1 on which the dielectric layer 3 is formed is impregnated with a conductive polymer solution or dispersion and dried to form at least part of the dielectric layer 3.

(4) Cathode layer forming step The cathode layer 5 composed of the carbon layer 5a and the metal paste layer 5b can be formed by sequentially applying a carbon paste and a metal paste on the surface of the solid electrolyte layer 4. it can. The configuration of the cathode layer 5 is not limited to this, and any configuration having a current collecting function may be used.

(5) Step of connecting anode lead terminal to anode body The anode wire 2 and the anode lead frame 131 are joined by laser welding, resistance welding, or the like.
First, the second portion 2 b of the anode wire 2 is placed on the notch N of the anode lead frame 131. When the anode wire 2 is elliptical, the anode wire 2 is placed on the notch N of the anode lead frame 131 so that the major axis direction is along the straight line Ln. In this case, it can be the same as the major diameter and the diameter D2 _H anode wires 2.

If the notch width Dn of the notch N is smaller than the first diameter D2 _H anode wires 2, as shown in FIG. 4 (a), the anode wire 2, the corners of the two points of the notch N (the 1 notch end portion 1311A and second notch end portion 1311B). When the anode wire 2 and the bottom portion NB are brought into contact with each other after welding, a minute clearance C (for example, 0. 0) considering the amount of sagging of the anode wire 2 between the anode wire 2 and the bottom portion NB before welding. 01 mm) is preferably provided. On the other hand, if the notch width Dn of the notch N is equal to or greater than the diameter D2 _H anode wires 2, for example, the first taper angle [theta] t ₁ and the second taper angle [theta] t ₂ set appropriately, the first side portion NS1 and The two points of the second side part NS2 are brought into contact with the anode wire 2.

  In any case, since the anode wire 2 placed on the anode lead frame 131 is supported at two points on the anode lead frame 131, the anode wire 2 is prevented from rolling. Further, even when the anode wire 2 is placed on the notch N so as to be shifted from a predetermined position, the anode wire 2 is guided to the two side portions NS of the notch N and fits in the predetermined position. . Therefore, the anode wire 2 can be placed at a predetermined position of the notch N without applying a load.

  Next, the anode lead frame 131 is melted and the anode wire 2 is welded. At this time, the method of melting the anode lead frame 131 is selected in consideration of the materials of the anode lead frame 131 and the anode wire 2.

(6) Step of connecting the cathode lead terminal to the cathode layer After applying the conductive adhesive to the cathode layer 5, the cathode lead terminal 14 is joined to the cathode layer 5 via the conductive adhesive. When the step (5) and the step (6) are performed at the same timing, that is, the capacitor element 10 coated with the conductive adhesive is mounted on the anode lead terminal 13 and the cathode lead terminal 14 arranged on the work table. Even when the anode lead frame 131 and the anode wire 2 are welded after being placed, the adhesion between the cathode lead terminal 14 and the cathode layer 5 is stabilized. This is because the drop of the anode wire 2 is suppressed and the inclination of the capacitor element 10 is suppressed. Furthermore, since the protrusion of the conductive adhesive is suppressed, the contamination of the apparatus is reduced.

(7) Step of sealing the capacitor element Next, the material of the capacitor element 10 and the exterior body 11 (for example, uncured thermosetting resin and filler) is accommodated in a mold, and transferred by a transfer molding method, a compression molding method, or the like. The capacitor element 10 is sealed with the outer package 11. At this time, a part of the anode lead terminal 13 and the cathode lead terminal 14 is exposed from the mold. The molding conditions are not particularly limited, and the time and temperature conditions may be appropriately set in consideration of the curing temperature of the thermosetting resin used.
The electrolytic capacitor 20 is manufactured by the above method.

  Since the electrolytic capacitor according to the present invention is excellent in connection reliability, it can be used for various applications.

20: Electrolytic capacitor 10: Capacitor element 1: Anode body 2: Anode wire 2a: First part of anode wire 2b: Second part of anode wire 3: Dielectric layer 4: Solid electrolyte layer 5: Cathode layer 5a: Carbon layer 5b : Metal paste layer 6: Anode portion 7: Cathode portion 11: Exterior body 13: Anode lead terminal 131, 131A to 131C: Anode lead frame 1311: First side
1311A: First notch end portion 1311B: Second notch end portion 1312: Second side N: Notch NS1: First side portion NS2: Second side portion NB: Bottom portion 132: Anode exposed portion 14: Cathode Lead terminal

Claims (5)

A capacitor element comprising an anode part and a cathode part;
An anode lead terminal electrically connected to the anode part;
A cathode lead terminal electrically connected to the cathode portion;
An exterior body that covers the capacitor element and exposes at least a part of each of the anode lead terminal and the cathode lead terminal; and
The anode part has an anode body and an anode wire extending from the anode body,
The anode lead terminal has a plate shape and an anode lead frame formed with a cutout part of the first side.
In a state where the main surface of the anode lead frame and the extending direction of the anode wire intersect, the end surface of the notch of the anode lead frame is melted and welded to the anode wire, The anode lead terminal is electrically connected,
The end surface of the notch includes a first side portion extending from a first notch end portion of one of the first sides toward a second side facing the first side, and the first side portion A second side portion extending from the other second notch end portion of the side toward the second side, and
The anode wire and the anode lead frame are welded at the first side portion and the second side portion,
When the cross section of the anode wire is viewed from the normal direction of the main surface of the anode lead frame with the second side in contact with a horizontal plane,
An acute angle θw ₁ formed by a straight line Lc passing through the center C of the cross section of the anode wire and a straight line Lw ₁ connecting the first welding mark on the first side portion and the center C; and
The electrolytic capacitor in which the acute angle θw ₂ formed by the straight line Lc and the straight line Lw ₂ connecting the second welding mark on the second side portion and the center C is greater than 0 ° and equal to or less than 45 °. When looking at the cross section of the anode wire,
The center C is located on a side opposite to the second side with respect to a straight line Ln connecting the first notch end portion and the second notch end portion of the notch. The electrolytic capacitor as described. An interval between the first side portion and the second side portion is reduced toward the second side;
When looking at the cross section of the anode wire,
The acute angle θt ₁ formed between the vertical direction and the first side part and the acute angle θt ₂ formed between the vertical direction and the second side part are both greater than 0 ° and 60 ° or less. 2. The electrolytic capacitor according to 2.   4. The electrolytic capacitor according to claim 1, wherein the cross section of the anode wire has a shape in which a first diameter along the straight line Ln is larger than a second diameter perpendicular to the straight line Ln. The end surface of the notch further includes an end portion different from the first notch end portion of the first side portion, and an end portion different from the second notch end portion of the second side portion. It has a bottom part to connect,
The electrolytic capacitor according to claim 1, wherein the anode wire is not welded to the bottom portion.

Images