JP2019067922A - Electrolytic capacitor - Google Patents

Abstract

To suppress interfacial peeling between a cathode lead terminal and a cathode part in an electrolytic capacitor.SOLUTION: An electrolytic capacitor includes a capacitor element, an anode lead terminal, a cathode lead terminal, and a resin casing, where a first groove and a second groove are formed on a first main surface in junction of the cathode lead terminal and the cathode part, in a first cross section that is perpendicular to the first main surface and cuts the first groove in a direction crossing the length direction, the first groove has a first a side face region and a first b side face region, in a second cross section that is parallel to the first cross section and cuts the second groove, the second groove has a second a side face region and a second b side face region, an angle θ1a formed by the first a side face region and the first main surface in the first groove satisfies 30°≤θ1a<90°, an angle θ1b formed by the first b side face region and the first main surface in the first groove satisfies 90°≤θ1b≤150°, and an angle θ2a formed by the second a side face region and the first main surface in the second groove satisfies 90°≤θ2a≤150°.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electrolytic capacitor, and more particularly to suppression of interfacial peeling of a cathode lead terminal.

  Electrolytic capacitors are mounted in various electronic devices because they have low equivalent series resistance (ESR) and excellent frequency characteristics. The electrolytic capacitor generally comprises a capacitor element having an anode portion and a cathode portion, an anode lead terminal electrically connected to the anode portion, a cathode lead terminal electrically connected to the cathode portion, and a resin sheath covering the capacitor element. And.

  One main surface of the cathode lead terminal is joined to the cathode portion by, for example, a conductive adhesive, and the other main surface is in contact with the resin sheath. Patent Document 1 proposes forming a groove or a recess on both main surfaces of a cathode lead terminal.

JP, 2006-237195, A

  According to Patent Document 1, the adhesion strength between the cathode lead terminal and the conductive adhesive and the adhesion between the cathode lead terminal and the resin sheath are improved by the groove or the recess. However, the effect of suppressing interfacial peeling between the cathode lead terminal and the cathode portion and the resin package is not sufficient.

  According to a first aspect of the present invention, there is provided a capacitor element comprising an anode part and a cathode part, an anode lead terminal electrically connected to the anode part, and an anode lead terminal electrically connected to the cathode part; A cathode lead terminal having a second main surface opposite to the first main surface; and a resin sheath covering the capacitor element and exposing at least a part of the anode lead terminal and the cathode lead terminal. The cathode lead terminal includes a bonding portion to be bonded to the cathode portion, and a first groove and a second groove different from the first groove in the first main surface of the bonding portion. In a first cross section in which a groove is formed and which is perpendicular to the first main surface and cuts the first groove in a direction intersecting the length direction, the first groove is a portion that corresponds to the first main surface. A second surface extending from the surface toward the second main surface the second groove in a second cross section that is parallel to the first cross section and cuts the second groove, the second groove having a side surface area and a first side surface area facing the first a side surface area; A second side surface region extending from the first main surface toward the second main surface, and a second 2b side surface region opposed to the second a side region, the first cross section and the second When the cross section is viewed from the same direction so that the side surface area 1a is located on the left side and the side surface area 1b is located on the right side, the side surface area 2a is located on the left side, and the side surface area 2b is An angle θ1a located on the right side and formed in the first groove by the first side surface area and the first main surface satisfies 30 ° ≦ θ1a <90 °, and the first side surface area and the first side The angle θ 1 b formed in the first groove by the main surface is 90 ° ≦ θ 1 The electrolytic capacitor satisfies b ≦ 150 ° and an angle θ2a formed in the second groove by the second side surface region and the first major surface satisfies 90 ° ≦ θ2a ≦ 150 °.

  According to the present invention, interfacial peeling between the cathode lead terminal and the cathode portion, and further, interfacial peeling between the cathode lead terminal and the resin sheath are suppressed. Thus, the increase in ESR is suppressed.

It is a cross section of an electrolytic capacitor concerning one embodiment of the present invention. It is a cross-sectional schematic diagram which expands and shows the 1st groove | channel formed in the junction part of the cathode lead terminal which concerns on one Embodiment of this invention. It is a cross-sectional schematic diagram which expands and shows the 2nd groove | channel formed in the junction part of the cathode lead terminal which concerns on one Embodiment of this invention. It is a top view which shows the 1st slot and the 2nd slot which were formed in the joined part of the cathode lead terminal concerning one embodiment of the present invention.

  The electrolytic capacitor according to the present embodiment is electrically connected to a capacitor element including an anode portion and a cathode portion, an anode lead terminal electrically connected to the anode portion, and a cathode portion, and has a first main surface and a first main surface. A cathode lead terminal having a second main surface opposite to the surface, and a resin sheath covering the capacitor element and exposing at least a part of the anode lead terminal and the cathode lead terminal.

  The cathode lead terminal comprises a junction that joins the cathode portion. A first groove and a second groove different from the first groove are formed on the first main surface of the joint portion. The first groove is perpendicular to the first main surface, and is a first side surface extending from the first main surface toward the second main surface in a first cross section which cuts the first groove in a direction intersecting the length direction And a first side surface region facing the first side surface region. The second groove is parallel to the first cross section, and in a second cross section that cuts the second groove, a second a side surface region extending from the first main surface toward the second main surface, and a second a side surface region And a second side surface region facing the second side.

  When the first cross section and the second cross section are viewed from the same direction so that the side surface area 1a is located on the left side and the side surface area 1b is located on the right side, the side surface area 2a is located on the left side, The 2b side area is located on the right. That is, when the first cross section and the second cross section are viewed from the same direction, the 1a side surface area corresponds to the 2a side surface area, and the 1b side surface area corresponds to the 2b side surface area.

  The angle θ1a formed in the first groove by the first side surface area and the first main surface satisfies 30 ° ≦ θ1a <90 °, and is formed in the first groove by the first side surface area and the first main surface The angle θ1b to be satisfied satisfies 90 ° ≦ θ1b ≦ 150 °. At this time, an angle θ2a formed in the second groove by the second side surface region and the first main surface satisfies 90 ° ≦ θ2a ≦ 150 °.

  By the first groove and the second groove formed in the first main surface, the contact area between the joint portion of the cathode lead terminal and the cathode portion or the resin sheath increases, and an anchor effect is generated. Furthermore, as described above, since the inclination direction of the first groove and the side surface of one of the second grooves is different, regardless of the direction of the stress applied to the joint portion, the joint portion of the cathode lead terminal and the cathode portion or resin sheath Interfacial peeling with can be suppressed.

  For example, when only the first groove having the side surface region as described above is formed in the joint portion, the force to resist the stress along the inclination direction of the 1a side surface region (or the 1b side surface region) is weak. Therefore, if stress occurs in this direction, interfacial peeling may occur. However, at least a portion (side area) of the side surface of the second groove corresponding to the 1a side surface area forming the acute internal angle is on the opposite side to the 1a side surface area (the internal angle is 90 ° or more ) Makes the resistance to the stress greater. Similarly, when stress is applied to the joint along the inclination direction of the 2a side surface region, the stress can be resisted by the first groove.

  When the first main surface of the junction of the cathode lead terminal faces the cathode portion, the first groove and the second groove are disposed on the junction surface of the cathode lead terminal with the cathode portion. Thereby, the interfacial peeling between the cathode lead terminal and the cathode portion is suppressed. In addition, since the movement of the cathode lead terminal is suppressed, the interfacial peeling between the cathode lead terminal and the resin sheath can be easily suppressed.

  On the other hand, when the second main surface of the joint portion of the cathode lead terminal faces the cathode portion, the first groove and the second groove are arranged on the joint surface of the cathode lead terminal with the resin sheath. In this case, interfacial peeling between the cathode lead terminal and the resin sheath is suppressed. In addition, since the movement of the cathode lead terminal is suppressed, the interface peeling between the cathode lead terminal and the cathode portion is also easily suppressed.

<Electrolytic capacitor>
The electrolytic capacitor according to one embodiment of the present invention will be described with reference to FIG. 1 by taking a solid electrolyte layer as an electrolyte as an example, but the present invention is not limited to this. FIG. 1 is a schematic cross-sectional view of the electrolytic capacitor 20 according to the present embodiment. In addition, in FIG. 1, the recessed part is abbreviate | omitted for convenience.

  Electrolytic capacitor 20 is electrically connected to capacitor element 10 having anode portion 6 and cathode portion 7, resin sheath body 11 for sealing capacitor element 10, and anode portion 6, and one from resin sheath body 11. An anode lead terminal 13 whose portion is exposed, and a cathode lead terminal 14 which is electrically connected to the cathode portion 7 and partially exposed from the resin case 11 are provided. The anode portion 6 has an anode body 1 including a dielectric layer 3 and an anode wire 2. The cathode portion 7 has a solid electrolyte layer 4 formed on the dielectric layer 3 and a cathode layer 5 covering the surface of the solid electrolyte layer 4.

<Capacitor element>
The capacitor element 10 according to the present embodiment will be described in detail.
(Anode part)
The anode portion 6 has an anode body 1 and an anode wire 2 extending from one surface of the anode body 1 and electrically connected to an 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, particles of valve metals such as titanium (Ti), tantalum (Ta) and niobium (Nb) are used. One 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 metal and silicon, vanadium, boron or the like can be used. Alternatively, a compound containing a valve metal and a typical element such as nitrogen may be used. The alloy of the valve metal is mainly composed of the valve metal, and for example, contains 50 atomic% or more of the valve metal.

  The anode wire 2 is made of a conductive material. The material of the anode wire 2 is not particularly limited, and examples thereof include copper, aluminum, an aluminum alloy and the like in addition to the above-mentioned valve metal. The materials constituting anode body 1 and anode wire 2 may be the same or different. The anode wire 2 has a first portion 2 a embedded in one side of the anode body 1 into the interior of the anode body 1 and a second portion 2 b extending from the one side of the anode body 1. The cross-sectional shape of the anode wire 2 is not particularly limited, and may be circular, track (a shape consisting of straight lines parallel to each other and two curves connecting the ends of the straight lines), oval, rectangle, polygon, etc. Be

  The anode part 6 is produced, for example, by pressure-forming a rectangular solid and sintering the first part 2a in a state of being embedded in the powder of the metal particles. Thereby, the second portion 2 b of the anode wire 2 is pulled out from one surface of the anode body 1 so as to be erected. The second portion 2 b is joined to the anode lead terminal 13 by welding or the like, and the anode wire 2 and the anode lead terminal 13 are electrically connected. The method of welding is not particularly limited, and resistance welding, laser welding, etc. may be mentioned.

  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 of forming a layer containing a metal oxide on the surface of the anode body 1, for example, a method of immersing the anode body 1 in a chemical conversion solution to anodize the surface of the anode body 1, oxygen The method of heating in the atmosphere containing is mentioned. The dielectric layer 3 is not limited to the layer containing the metal oxide, as long as it has insulating properties.

(Cathode part)
The cathode portion 7 has a solid electrolyte layer 4 formed on the dielectric layer 3 and a cathode layer 5 covering the solid electrolyte layer 4.
The solid electrolyte layer 4 may be formed to cover at least a part of the dielectric layer 3. For the solid electrolyte layer 4, for example, a manganese compound or a conductive polymer is used. As the conductive polymer, polypyrrole, polythiophene, polyfuran, polyaniline, polyacetylene, polyphenylene, polyparaphenylene vinylene, polyacene, polythiophene vinylene, polyfluorene, polyvinylcarbazole, polyvinylphenol, polypyridine, or derivatives of these polymers, etc. It can be mentioned. These may be used alone or in combination of two or more. The conductive polymer may also be a copolymer of two or more monomers. It may be polythiophene, polyaniline, or polypyrrole in terms of excellent conductivity. In particular, it may be polypyrrole in that it is excellent in 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, formation method (polymerization method), etc. of the conductive polymer used in each layer may be different.

  In the present specification, polypyrrole, polythiophene, polyfuran, polyaniline and the like mean a polymer having polypyrrole, polythiophene, polyfuran, polyaniline and the like as a basic skeleton, respectively. Thus, polypyrrole, polythiophene, polyfuran, polyaniline and the like may also include their 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 for forming the conductive polymer, or the solution or dispersion liquid of the conductive polymer. The dopant is not particularly limited, but 1,5-naphthalenedisulfonic acid, 1,6-naphthalenedisulfonic acid, 1-octanesulfonic acid, 1-naphthalenesulfonic acid, 2-naphthalenesulfonic acid, 2,6-naphthalenedisulfonic acid, 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, polyvinyl sulfone Acid, methanesulfonic acid, and, derivatives thereof, and the like. Examples of the derivative include metal salts such as lithium salt, potassium salt and sodium salt, ammonium salts such as methyl ammonium salt, dimethyl ammonium salt and trimethyl ammonium salt, piperidium salt, pyrrolidinium salt and pyrrolinium salt.

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

  The cathode layer 5 has, for example, a carbon layer 5 a formed to cover the solid electrolyte layer 4 and a metal paste layer 5 b formed on the surface of the carbon layer 5 a. The carbon layer 5a contains a conductive carbon material such as graphite and a resin. The metal paste layer 5b contains, for example, metal particles (for example, silver) and a resin. The configuration of the cathode layer 5 is not limited to this configuration. The configuration of the cathode layer 5 may be a configuration having a current collecting function.

<Anode lead terminal>
The anode lead terminal 13 is electrically connected to the anode body 1 via the second portion 2 b of the anode wire 2. The material of the anode lead terminal 13 is not particularly limited as long as it is electrochemically and chemically stable and has conductivity. The anode lead terminal 13 may be, for example, a metal such as copper or nonmetal. The shape is not particularly limited as long as it is flat. The thickness of the anode lead terminal 13 (the distance between the main surfaces of the anode lead terminal 13) may be 25 μm to 200 μm or 25 μm to 100 μm from the viewpoint of shortening the height.

  The anode lead terminal 13 may be joined to the anode wire 2 by a conductive adhesive or solder, or may be joined to the anode wire 2 by resistance welding or laser welding. The conductive adhesive is, for example, a mixture of a thermosetting resin described later and carbon particles or metal particles.

<Cathode lead terminal>
The cathode lead terminal 14 is electrically connected to the cathode portion 7 at the bonding portion 14 a. The bonding portion 14 a is a portion overlapping the cathode layer 5 of the cathode lead terminal 14 when the cathode layer 5 and the cathode lead terminal 14 bonded to the cathode layer 5 are viewed from the normal direction of the cathode layer 5.

  The cathode lead terminal 14 is bonded to the cathode layer 5 via the conductive adhesive 8, for example. One end of the cathode lead terminal 14 constitutes, for example, a part of the bonding portion 14 a and is disposed inside the resin sheath 11. The other end of the cathode lead terminal 14 is led out from the lead-out surface 11X of the resin package 11. Therefore, a part including the other end of the cathode lead terminal 14 is exposed from the resin package 11.

  The material of the cathode lead terminal 14 is also not particularly limited as long as it is electrochemically and chemically stable and has conductivity. The cathode lead terminal 14 may be, for example, a metal such as copper or nonmetal. The shape is also not particularly limited, and is, for example, long and flat. The thickness T of the cathode lead terminal 14 may be 25 μm to 200 μm or 25 μm to 100 μm from the viewpoint of shortening the height.

  A first groove and a second groove are formed on the first main surface of the bonding portion 14 a of the cathode lead terminal 14. As a result, the effect of suppressing interfacial peeling between the first main surface and the cathode 7 and the resin sheath 11 opposed to the first main surface is enhanced.

  The groove is perpendicular to an arbitrary side of the smallest rectangle surrounding the opening when the opening formed on the first main surface of the groove is viewed from the normal direction of the first main surface, sharing the side with the apex, and a vertex The case where the ratio of length to one side exceeds 2 is referred to. The outer shape of the opening is not particularly limited, and may be a straight line, a curved line, or a shape including a straight line part and a curved line part.

  The first and second grooves (hereinafter sometimes simply referred to as “grooves”) may be described in detail with reference to FIGS. 2 and 3. FIG. 2 is an enlarged schematic cross-sectional view showing the first groove 141 formed in the bonding portion 14 a of the cathode lead terminal 14, and FIG. 3 is a second groove formed in the bonding portion 14 a of the cathode lead terminal 14. It is a cross-sectional schematic diagram which expands and shows 142. FIG. In the illustrated example, the first main surface 14X (the first groove 141 and the second groove 142) is opposed to the cathode portion 7 with the conductive adhesive 8 interposed therebetween.

  The first major surface 14X may be opposed to the resin sheath 11. Each groove may be formed on the second major surface 14Y in addition to the first major surface 14X. At this time, from the viewpoint of maintaining strength, the groove formed on the first major surface 14X and the groove formed on the second major surface 14Y do not overlap when viewed from the normal direction of the first major surface 14X. It may be located at

  The first groove 141 is perpendicular to the first major surface 14X, and cuts from the first major surface 14X to the second major surface 14Y in a first cross section that cuts the first groove 141 in the direction intersecting the length direction. And a first side surface region 141b opposed to the first side surface region 141a. The longitudinal direction of the first groove 141 is a direction indicated by a longer straight line connecting the center of one end of the opening formed in the first major surface 14X by the first groove 141 and the center of the other end. It is.

  The second groove 142 is parallel to the first cross section, and in a second cross section that cuts the second groove 142, the second groove side surface area 142a extending from the first major surface 14X to the second major surface 14Y And 2b side surface area 142b opposite to 2a side surface area 142a. The first and second cross sections do not have to be on the same plane, but are parallel to each other.

  When the first cross section and the second cross section are viewed in the same direction, the 1a side area 141a corresponds to the 2a side area 142a, and the 1b side area 141b corresponds to the 2b side area 142b. That is, when the 1a side surface area 141a constitutes the left side surface in the first cross section, the 2a side surface area 142a constitutes the left side surface in the second cross section.

  The angle θ1a formed in the first groove 141 by the first side surface area 141a and the first main surface 14X satisfies 30 ° ≦ θ1a <90 °, and the first side surface area 141b and the first main surface 14X form the first The angle θ1b formed in the one groove 141 satisfies 90 ° ≦ θ1b ≦ 150 °. That is, the 1a side surface area 141a and the 1b side surface area 141b extend in the same direction, for example, do not intersect in the first cross section. In the same direction, the extension line of the 1a side surface area 141a and the extension line of the 1b side surface area 141b do not intersect (parallel), or the angle between the extension lines is greater than 0 ° and not more than 30 ° The range is The first side surface area 141 a and the first side surface area 141 b may be parallel to each other in terms of facilitating the formation of the groove.

  On the other hand, an angle θ2a formed in the second groove 142 by the second side surface region 142a corresponding to the first side surface region 141a and the first main surface 14X satisfies 90 ° ≦ θ2a ≦ 150 °.

  That is, the extension line of the 1a side surface area 141a (or the 1b side surface area 141b) and the extension line of the 2a side surface area 142a are, for example, smaller angles of 30 ° or more and 150 ° between the extension lines. It crosses in the range which becomes below. As described above, in a specific cross section, the interface peeling can be performed regardless of the direction of the stress applied to the joint by the difference in the inclination direction of the 2a side surface region corresponding to the 1a side surface region of the first groove and the 2nd groove. Is suppressed.

  The angle θ2b formed in the second groove 142 by the second side surface area 142b and the first main surface 14X is not particularly limited. As long as the 2a side surface area corresponding to the 1a side surface area forming the acute internal angle is inclined so that the internal angle is 90 ° or more, the effect of suppressing interfacial peeling is obtained regardless of the angle θ2b. The angle θ2b may satisfy 30 ° ≦ θ2b ≦ 90 ° in that the effect of suppressing interfacial peeling is further enhanced. In this case, the 2a side surface area 142a and the 2b side surface area 142b extend in the same direction, for example, do not intersect in the second cross section. In the same direction, the extension line of the 2a side surface area 142a and the extension line of the 2b side surface area 142b do not intersect (are parallel) or the smaller angle between the extension lines is larger than 0 °, It is a range which becomes less than 30 degrees.

  The angle θ1a may be 30 ° <θ1a <90 ° or may be 45 ° ≦ θ1a ≦ 80 °. The angle θ1b may be 90 ° <θ1b ≦ 150 ° or 100 ° ≦ θ1b ≦ 135 °. The angle θ2a may be 90 ° <θ2a ≦ 150 °, and may be 100 ° ≦ θ2a ≦ 135 °. The angle θ2b may be 30 ° ≦ θ2b <90 °, and may be 45 ° ≦ θ2b ≦ 80 °. The angles θ1a and θ2b may be the same or different. The angles θ1 b and θ2 a may be the same or different. The sum of the angles θ1a and θ1b may be 180 °, and the sum of the angles θ2a and θ2b may be 180 °.

  At least one first groove 141 and second groove 142 which satisfy the relationship as described above may be formed in the bonding portion 14a. In other words, the first groove 141 in the first cross section and the grooves other than the first groove 141 in the cross section which is not parallel to the first cross section may not satisfy the above relationship. Moreover, even if it is a cross section parallel to the first cross section, there may be a groove other than the first groove 141 which does not satisfy the above relationship.

  In the first cross section, the side surface including the 1a side surface area 141a of the first groove 141 may have a side surface area other than the 1a side surface area 141a, and the side surface including the 1b side surface area 141b is the 1b side surface A side area other than the area 141b may be provided. Similarly, in the second cross section, the side surface including the 2a side surface region 142a of the second groove 142 may have a side surface region other than the 2a side surface region 142a, and the side surface including the 2b side surface region 142b is A side surface area other than the 2b side surface area 142b may be provided. However, it is preferable that one side surface of the first groove 141 is constituted only by the 1a side surface area 141a, and the other side surface is constituted only by the 1b side surface area 141b, from the viewpoint of peeling suppression and processability. Is preferred. From the same point of view, it is preferable that one side surface of the second groove 142 is constituted only by the 2a side surface region 142a, and the other side is preferably constituted only by the 2b side surface region 142b. . The bottoms of the first groove 141 and the second groove 142 may be flat or may have a curved surface.

  The depth H of the groove is not particularly limited as long as it is smaller than the thickness T of the cathode lead terminal 14. From the viewpoint of strength, the depth H of the groove may be 10% to 90% or 20% to 50% of the thickness T. The depth H of the groove is the shortest distance from the portion closest to the second main surface 14Y of the groove to the first opening (or the first main surface 14X). The depths of the first and second grooves may be the same or different. Moreover, the depth of each groove may or may not be constant.

  The longitudinal direction of the groove (or the opening formed by the groove in the first major surface 14X) and the extending direction D of the cathode lead terminal 14 may intersect (see FIG. 4). FIG. 4 shows the case where the longitudinal direction of the groove and the extending direction D of the cathode lead terminal 14 are orthogonal to each other. The extending direction D of the cathode lead terminal 14 is on the first major surface 14X, and the cathode lead terminal 14 is exposed from the bonding portion 14a (specifically, for example, one end of the cathode lead terminal 14). The direction is toward the lead-out surface 11X of the resin outer package 11 to be started. FIG. 4 is a top view showing the first groove 141 and the second groove 142 formed in the bonding portion 14 a of the cathode lead terminal 14 according to the present embodiment.

  The exposed portion of the cathode lead terminal 14 is usually bent along the lead-out surface 11X in at least one of the inside and the outside of the resin package 11. Therefore, the joint portion 14 a is likely to be stressed to pull the cathode lead terminal 14 in the extending direction and to separate it from the cathode portion 7 or the resin sheath 11. Therefore, by forming the grooves in the direction intersecting with the extending direction of the cathode lead terminal 14, the resistance to the stress is increased, and the interfacial peeling can be further suppressed. The angle between the longitudinal direction of the groove (or opening) and the extending direction of the cathode lead terminal 14 may be 90 °, and the longitudinal direction of the groove (opening) and the extending direction of the cathode lead terminal 14 are The smaller angle θ may be 45 ° ≦ θ <90 °.

  In this case, the length in the longitudinal direction of the groove (or opening) (hereinafter simply referred to as the groove length) is a direction perpendicular to the extending direction of the cathode lead terminal 14 from the viewpoint of suppressing peeling. It may be 10% to 120% of the length. The lengths of the first groove 141 and the second groove 142 may be the same or different.

  The length (width) in the direction perpendicular to the length direction of the groove is not particularly limited, and may be, for example, 1/35 or more and 1/2 or less of the length of the groove, 1/10 or more, 1/1 or more. It may be 3 or less. The length of the groove is, for example, 200 μm to 3500 μm, and may be 1000 μm to 3000 μm. The width of the groove is, for example, 100 μm to 1000 μm, and may be 200 μm to 500 μm. The widths of the first groove 141 and the second groove 142 may be the same or different.

  One or more first grooves 141 and second grooves 142 may be formed in the first major surface 14X of the bonding portion 14a. From the viewpoint of enhancing the anchor effect, a plurality of grooves may be formed in the first major surface 14X of the joint portion 14a. In this case, the grooves may be formed in parallel, may be formed to intersect, or may be formed randomly. In addition, the first groove 141 and the second groove 142 may be formed parallel to each other, may be formed to intersect each other, or may be formed randomly. When the first grooves 141 and the second grooves 142 are formed in parallel to each other, the grooves may be alternately formed one by one or plural (see FIG. 4).

  From the viewpoint of enhancing the effect of suppressing interfacial peeling, the area of the first opening formed by the one or more first grooves in the first major surface 14X, and the one or more second grooves are the first. The total area of the second openings formed in the major surface 14X may be 5% to 50%, or 10% to 20% of the area of the first major surface 14X. From the same viewpoint, the difference between the ratio of the area of the first opening to the first major surface 14X and the ratio of the area of the second opening to the first major surface 14X may be 0% to 20%. , 0% to 10%.

  When the first major surface 14X (the first groove 141 and the second groove 142) faces the cathode portion 7, for example, a part of the conductive adhesive 8 intrudes into each groove to produce an anchor effect, and a cathode lead Interfacial peeling between the terminal 14 and the cathode portion 7 is suppressed. On the other hand, when the first main surface 14X is opposed to the resin package 11, a part of the resin package 11 intrudes into each groove to produce an anchor effect, and the interface peeling between the cathode lead terminal 14 and the resin package 11 Is suppressed. Similarly, when each groove is formed in the first main surface 14X and the second main surface 14Y, the interface peeling between the cathode lead terminal 14 and the cathode portion 7 and the peeling of the cathode lead terminal 14 and the resin sheath body 11 are similarly obtained. Interfacial peeling is suppressed.

<Resin exterior body>
The resin package 11 is provided to electrically insulate the anode lead terminal 13 and the cathode lead terminal 14, and is made of an insulating material. The resin sheath 11 contains, for example, a cured product of a thermosetting resin. As a thermosetting resin, an epoxy resin, a phenol resin, a silicone resin, a melamine resin, a urea resin, an alkyd resin, a polyurethane, a polyimide, unsaturated polyester etc. are mentioned, for example.

An example of the manufacturing method of the electrolytic capacitor which concerns on this embodiment is demonstrated.
«Method of manufacturing electrolytic capacitor»
(1) Preparation of Anode Body A valve metal particle and an anode wire 2 are put in a mold so that the first portion 2a is embedded in the valve metal particle, pressed and then sintered in vacuum. The anode body 1 is produced in which the first portion 2a is embedded in one side of the porous sintered body. The pressure in pressure molding is not particularly limited, and is, for example, about 10 to 100 N. The valve metal particles may be mixed with a binder such as polyacrylic carbonate, if necessary.

(2) Step of Forming Dielectric Layer A dielectric layer 3 is formed on the anode body 1. Specifically, the anode body 1 is immersed in a chemical conversion tank filled with an electrolytic aqueous solution (for example, a 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 to perform anodic oxidation By doing this, the dielectric layer 3 made of an oxide film of a valve metal can be formed on the surface of the anode body 1. The electrolytic aqueous solution is not limited to the phosphoric acid aqueous solution, and nitric acid, acetic acid, sulfuric acid and the like can be used.

(3) Step of Forming Solid Electrolyte Layer In this embodiment, a step of forming the solid electrolyte layer 4 containing a conductive polymer will be described.
The solid electrolyte layer 4 containing a conductive polymer is, for example, a method of impregnating the anode body 1 on which the dielectric layer 3 is formed with a monomer or an oligomer and thereafter polymerizing the monomer or the oligomer by chemical polymerization or electrolytic polymerization; Alternatively, it is formed on at least a part of the dielectric layer 3 by impregnating the anode body 1 on which the dielectric layer 3 is formed with a solution or dispersion of a conductive polymer and drying.

(4) Step of Forming Cathode Layer A carbon paste and a metal paste are sequentially applied on the surface of the solid electrolyte layer 4 to form the cathode layer 5 composed of the carbon layer 5a and the metal paste layer 5b. The configuration of the cathode layer 5 is not limited to this, as long as it has a current collecting function.
The capacitor element 10 is manufactured by the above method.

(5) Bonding Step of Anode Lead Terminal One end of the anode wire 2 implanted from the anode body 1 is bonded to the anode lead terminal 13 by laser welding, resistance welding, or the like.

(6) Preparation of cathode lead terminal and bonding process A first groove 141 and a second groove 142 are formed in a precursor of the cathode lead terminal 14. Each groove is formed, for example, by pressing a pressing die having a prismatic convex portion against a predetermined position of the precursor from an oblique direction. At this time, by changing the pressing direction of the press die and pressing a plurality of times, the first groove 141 and the second groove 142 which are inclined in different directions are formed.

  After applying the conductive adhesive 8 to the cathode layer 5, the cathode lead terminal 14 having the first groove 141 and the second groove 142 is bonded to the cathode portion 7 through the conductive adhesive 8. At this time, the main surface on which the first groove 141 and the second groove 142 are formed may be bonded to the cathode portion 7 or the opposite main surface may be bonded to the cathode portion 7.

(7) Sealing step of capacitor element The capacitor element 10 and the resin (the material of the resin outer package 11 such as an uncured thermosetting resin and a filler) to which the anode lead terminal 13 and the cathode lead terminal 14 are connected are molds And the capacitor element 10 is sealed with the resin sheath 11 by transfer molding, compression molding or the like. At this time, a part of the anode lead terminal 13 and the cathode lead terminal 14 is led out of 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 to be used.

  The electrolytic capacitor according to the present invention can be used in various applications because the increase in ESR is suppressed.

20: electrolytic capacitor 10: capacitor element 1: anode body 2: anode wire 2a: first portion 2b: second portion 3: dielectric layer 4: solid electrolyte layer 5: cathode layer 5a: carbon layer 5b: metal paste layer 6: Anode part 7: Cathode part 8: conductive adhesive 11: resin outer package 11X: lead-out surface 13: anode lead terminal 14: cathode lead terminal 14a: joint 14X: first main surface 14Y: second main surface 141: first main surface 1 groove 141a: 1a side surface area 141b: 1b side surface area 142: 2nd groove 142a: 2a side surface area 142b: 2b side surface area

Claims (5)

A capacitor element comprising an anode part and a cathode part;
An anode lead terminal electrically connected to the anode portion;
A cathode lead terminal electrically connected to the cathode portion and having a first main surface and a second main surface opposite to the first main surface;
An electrolytic capacitor comprising: a resin sheath covering the capacitor element and exposing at least a part of the anode lead terminal and the cathode lead terminal.
The cathode lead terminal includes a bonding portion to be bonded to the cathode portion,
A first groove and a second groove different from the first groove are formed in the first main surface of the joint portion,
In a first cross section perpendicular to the first main surface, the first groove being cut in a direction intersecting the length direction
The first groove includes a first side surface area extending from the first main surface toward the second main surface, and a first side surface area opposed to the first a side surface area,
In a second cross section which is parallel to the first cross section and cuts the second groove,
The second groove includes a second side surface area extending from the first main surface toward the second main surface, and a second side surface area opposed to the second a side surface area,
When the first cross section and the second cross section are viewed from the same direction so that the first side surface area is located on the left side and the first 1b side area is located on the right side,
Said 2a side area is located on the left side,
Said 2b side area is located on the right side,
An angle θ1a formed in the first groove by the first side surface region and the first main surface satisfies 30 ° ≦ θ1a <90 °.
An angle θ1b formed in the first groove by the first side surface area and the first main surface satisfies 90 ° ≦ θ1b ≦ 150 °.
An electrolytic capacitor, wherein an angle θ2a formed in the second groove by the second side surface region and the first main surface satisfies 90 ° ≦ θ2a ≦ 150 °.   The electrolytic capacitor according to claim 1, wherein an angle θ2b formed in the second groove by the second side surface region and the first main surface satisfies 30 ° ≦ θ2b ≦ 90 °. The angle θ2a satisfies 90 ° <θ2a ≦ 150 °.
The electrolytic capacitor according to claim 2, wherein the angle θ2b satisfies 30 ° ≦ θ2b <90 °.   The electrolytic capacitor according to any one of claims 1 to 3, wherein the first main surface in the joint portion faces the cathode portion.   The electrolytic capacitor according to any one of claims 1 to 3, wherein the second main surface of the joint portion faces the cathode portion.

Images