Electrolytic capacitor

Abstract

This electrolytic capacitor comprises: a capacitor element that includes a plurality of electrode parts; a current collector plate that is connected to each of the plurality of electrode parts; a lead terminal that is connected to the current collector plate; and a case that accommodates the capacitor element and the current collector plate. The case has a housing and a sealing body that closes an opening of the housing. The sealing body has a metal sealing plate and a sealing rubber that fits into a first through-hole provided in the sealing plate. The lead terminal is inserted into a second through-hole provided in the sealing rubber, and part of the lead terminal is exposed to the outside of the case. A first portion of the sealing rubber is disposed between the collector plate and the sealing plate in a state of being compressed by the collector plate and the sealing plate. A second portion is inserted into the first through-hole.

Description

electrolytic capacitor

[0001] The present disclosure relates to an electrolytic capacitor, and more particularly to an electrolytic capacitor including a case that houses a capacitor element.

[0002] Patent Document 1 discloses a capacitor including a metal case that houses a capacitor element and a sealing body that closes the opening of the metal case. The sealing body includes a substrate and rubber integrated with the substrate. The substrate has a terminal insertion hole that is larger than the outer diameter of the lead terminal. The lead terminal is inserted into the terminal insertion hole in the substrate. In Patent Document 1, in order to improve the sealing performance inside the metal case, OH groups are generated on the surface of the substrate that constitutes the sealing body, and the substrate and rubber are bonded together by chemical bonding.

[0003] JP 2012-142424 A

[0004] An electrolytic capacitor according to one aspect of the present disclosure includes a capacitor element including a plurality of electrode portions, current collector plates connected to each of the plurality of electrode portions, lead terminals connected to the current collector plates, and a case that houses the capacitor element and the current collector plates. The case includes a housing having an opening and a sealing body that closes the opening of the housing. The sealing body includes a metal sealing plate having a first through hole and a sealing rubber that fits into the first through hole. The lead terminal protrudes from a surface of the current collector plate facing the sealing plate and is inserted into a second through hole provided in the sealing rubber, with a portion of the lead terminal exposed to the outside of the case. The sealing rubber has a first portion and a second portion. The first portion is larger than the first through hole and is positioned between the current collector plate and the sealing plate while being compressed by the current collector plate and the sealing plate. The second portion is inserted into the first through hole.

[0005] According to the present disclosure, it is possible to provide an electrolytic capacitor with improved airtightness while suppressing a decrease in productivity.

[0006] FIG. 1 is a perspective view of the exterior of a capacitor body of an electrolytic capacitor according to an embodiment of the present disclosure, as viewed from below. FIG. 2 is a perspective view of the exterior of an electrolytic capacitor according to an embodiment of the present disclosure, as viewed from above. FIG. 3 is a perspective view of the exterior of an electrolytic capacitor according to an embodiment of the present disclosure, as viewed from below. FIG. 4 is an exploded perspective view of an electrolytic capacitor according to an embodiment of the present disclosure, as viewed from above. FIG. 5 is an exploded perspective view of an electrolytic capacitor according to an embodiment of the present disclosure, as viewed from below. FIG. 6 is a schematic cross-sectional view of an electrolytic capacitor according to an embodiment of the present disclosure. FIG. 7 is a schematic cross-sectional view of a capacitor body according to an embodiment of the present disclosure. FIG. 8 is a schematic plan view of a capacitor body according to a modified example of an embodiment of the present disclosure, with the housing removed. FIG. 9 is a schematic cross-sectional view of a capacitor body according to a modified example of an embodiment of the present disclosure. FIG. 10 is a side view of a rubber seal included in an electrolytic capacitor according to a modified example of an embodiment of the present disclosure. FIG. 11 is a side view of a rubber seal included in an electrolytic capacitor according to a modified example of an embodiment of the present disclosure. FIG. 12 is a perspective view of a rubber seal included in an electrolytic capacitor according to a modified example of an embodiment of the present disclosure. FIG. 13 is a cross-sectional view of a main part illustrating an attached state of a sealing rubber provided in an electrolytic capacitor according to a modified example of an embodiment of the present disclosure.

[0007] In Patent Document 1, the substrate and rubber are bonded together by chemical bonding in order to increase the airtightness inside the metal case, which requires pre-processing for chemical bonding, which could lead to reduced productivity.

[0008] The present disclosure provides an electrolytic capacitor with improved airtightness while suppressing a decrease in productivity.

[0009] Electrolytic capacitors according to embodiments will be described in detail below with reference to the drawings. However, the drawings described in the following embodiments are schematic diagrams, and the dimensional ratios of the sizes of the components do not necessarily reflect the actual dimensional ratios. Furthermore, the configurations described in the following embodiments are merely examples of the present disclosure. The present disclosure is not limited to the following embodiments, and various modifications are possible depending on the design, etc., as long as the effects of the present disclosure can be achieved.

[0010] (Embodiment) (1) Overview As shown in Figures 1 to 7, the electrolytic capacitor 1 of this embodiment includes a capacitor element 10 including a plurality of electrode portions 11, a plurality of current collector plates 13, a plurality of lead terminals 16, and a case 20.

[0011] The plurality of current collector plates 13 are connected to the plurality of electrode portions 11, respectively. The plurality of lead terminals 16 are connected to the plurality of current collector plates 13, respectively. The case 20 houses the capacitor element 10 and the plurality of current collector plates 13. The case 20 has a housing 21 having an opening 24, and a sealing body 30 that closes the opening 24 of the housing 21.

[0012] The sealing body 30 has a metal sealing plate 31 having a plurality of first through holes 32 formed therein, and sealing rubbers 40 that fit into the plurality of first through holes 32, respectively.

[0013] The lead terminal 16 protrudes from the surface of the current collector plate 13 facing the sealing plate 31 and is inserted into a second through-hole 44 provided in the sealing rubber 40 , with a portion of the lead terminal 16 exposed to the outside of the case 20 .

[0014] The sealing rubber 40 has a first portion 41 and a second portion 42. The first portion 41 is larger than the first through-hole 32 and is disposed between the current collector plate 13 and the sealing plate 31 in a state where the first portion 41 is compressed by the current collector plate 13 and the sealing plate 31. The second portion 42 is inserted into the first through-hole 32.

[0015] In the electrolytic capacitor 1 of this embodiment, the case 20 that houses the capacitor element 10 includes a housing 21 and a sealing body 30 that closes the opening 24 of the housing 21. The sealing body 30 includes a metal sealing plate 31 and a sealing rubber 40 attached to a first through hole 32 of the sealing plate 31. Therefore, compared to when the entire opening 24 of the housing 21 is closed with rubber, the area of ​​the portion closed with the sealing rubber 40 can be made smaller, thereby reducing the amount of volatilized electrolyte that permeates the rubber and leaks to the outside of the case 20. Furthermore, the second portion 42 of the sealing rubber 40 is inserted into the first through hole 32, and the first portion 41 is disposed between the current collector plate 13 and the sealing plate 31. The thickness of the first portion 41 of the sealing rubber 40 before the opening 24 of the housing 21 is sealed with the sealing body 30 is set to be larger than the gap that will be formed between the current collector plate 13 and the sealing plate 31 after the opening 24 of the housing 21 is sealed with the sealing body 30. As a result, after the opening 24 of the housing 21 is sealed with the sealing body 30, the sealing rubber 40 is attached to the sealing plate 31 with the first portion 41 compressed between the current collector plate 13 and the sealing plate 31. Therefore, since the sealing rubber 40 is attached to the sealing plate 31 without being chemically bonded to the sealing plate 31, it is possible to provide an electrolytic capacitor 1 with improved airtightness while suppressing a decrease in productivity. Furthermore, by improving the airtightness of the electrolytic capacitor 1, the amount of volatilized electrolyte that permeates the rubber and leaks to the outside of the case 20 can be reduced, even when the electrolytic capacitor 1 is used in a high-temperature environment or for a long period of time. This suppresses performance degradation due to a decrease in the electrolyte, thereby extending the life of the electrolytic capacitor 1. In this configuration, by increasing the thickness of the first portion 41 of the sealing rubber 40 before the opening 24 of the housing 21 is sealed with the sealing body 30, it is possible to increase the compressive force (adhesion force) applied to the first portion 41 and obtain sufficient airtightness.

[0016] (2) Details The electrolytic capacitor 1 according to this embodiment will be described in detail below with reference to Figures 1 to 7. In this embodiment, as a representative example, the electrolytic capacitor 1 will be described as a hybrid electrolytic capacitor 1 that includes, as an electrolyte, a liquid component (not shown) such as an electrolytic solution and a conductive polymer.

[0017] (2.1) Configuration The electrolytic capacitor 1 of this embodiment includes a capacitor body 2 (see FIG. 1 ) and a seat plate member 3 to which the capacitor body 2 is attached. The capacitor body 2 includes a capacitor element 10 including a plurality of (e.g., two) electrode portions 11 described above, a plurality of (e.g., two) current collecting plates 13, a plurality of (e.g., two) lead terminals 16, and a case 20.

[0018] The seat plate member 3 is used to convert the electrolytic capacitor 1 into a surface-mount type capacitor. In the case of insertion mounting, in which the lead terminals 16 of the electrolytic capacitor 1 are inserted into through-holes in a printed wiring board and soldered, the seat plate member 3 is not necessary, and the electrolytic capacitor 1 only needs to include the capacitor body 2.

[0019] In this embodiment, the multiple electrode portions 11 include one anode portion 11A and one cathode portion 11B. The electrolytic capacitor 1 also includes multiple (e.g., two) current collector plates 13. The current collector plate 13 connected to the anode portion 11A may be referred to as a first current collector plate 13A, and the current collector plate 13 connected to the cathode portion 11B may be referred to as a second current collector plate 13B. The electrolytic capacitor 1 also includes multiple (e.g., two) lead terminals 16. The lead terminal 16 connected to the first current collector plate 13A may be referred to as a first lead terminal 16A, and the lead terminal 16 connected to the second current collector plate 13B may be referred to as a second lead terminal 16B.

[0020] 2, 4, etc., the X-axis direction is defined as the left-right direction, the Y-axis direction as the front-rear direction (depth direction), and the Z-axis direction as the up-down direction. The positive X-axis direction is defined as the right side, the positive Y-axis direction as the front side, and the positive Z-axis direction as the top side. However, these directions are merely examples and are not intended to limit the directions in which the electrolytic capacitor 1 is used. The arrows indicating the various directions in the drawings are merely shown for explanatory purposes and have no substance.

[0021] (Capacitor Element) As shown in Figures 6 and 7, the capacitor element 10 is housed in a case 20. As shown in Figures 4 to 7, the capacitor element 10 has a plurality of (for example, two) electrode portions 11. The plurality of electrode portions 11 includes an anode portion 11A and a cathode portion 11B.

[0022] Capacitor element 10 includes one or more anode foils 12A each having an anode portion 11A, one or more cathode foils 12B each having a cathode portion 11B, and a separator 18 and a conductive polymer disposed between anode foil 12A and cathode foil 12B (see FIGS. 6 and 7 ). Anode foil 12A, cathode foil 12B, and separator 18 are stacked in an opposing direction DR1 in which bottom surface 22 of housing 21 and sealing body 30 face each other. Note that a connection portion of one or more anode foils 12A with first current collector 13A constitutes anode portion 11A, and a connection portion of one or more cathode foils 12B with second current collector 13B constitutes cathode portion 11B.

[0023] The anode foil 12A has a dielectric layer on its surface, and at least a portion of the surface of the dielectric layer is covered with a solid electrolyte layer. The solid electrolyte layer contains a conductive polymer component. A liquid component, which is an electrolytic solution, is contained inside the case 20. In other words, the electrolytic capacitor 1 has a liquid component contained in the case 20, and the liquid component is impregnated into the capacitor element 10. The liquid component permeates the solid electrolyte layer and is in contact with the solid electrolyte layer, which is partially covered with the conductive polymer component, and the dielectric layer.

[0024] The separator 18 can also hold an electrolyte such as an electrolytic solution and a conductive polymer.

[0025] The anode foil 12A includes a metal foil containing a valve metal such as aluminum, tantalum, or niobium, and a dielectric layer formed on the surface of the metal foil. The anode foils 12A are thin plates that are rectangular in plan view. One side (e.g., the left side) of the anode foils 12A is connected to the first current collector 13A.

[0026] The cathode foils 12B include metal foils such as aluminum foils. Each of the cathode foils 12B is a thin plate having a rectangular shape in a plan view. One side (e.g., the right side) of each of the cathode foils 12B is connected to the second current collector plate 13B.

[0027] Electrolytic capacitor 1 of this embodiment includes a stacked capacitor element 10 as capacitor element 10. As shown in Figures 6 and 7 , stacked capacitor element 10 includes, for example, anode foil 12A, cathode foil 12B, and separator 18 stacked in facing direction DR1 in which bottom surface 22 of housing 21 and sealing body 30 face each other.

[0028] The liquid component may contain a solute. That is, the liquid component is, for example, an electrolytic solution containing a solvent and a solute. For example, an organic solvent or the like is used for the electrolytic solution. Examples of the organic solvent include polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, and propylene glycol; sulfone compounds such as sulfolane, dimethyl sulfoxide, and diethyl sulfoxide; lactone compounds such as γ-butyrolactone and γ-valerolactone; carbonate compounds such as dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, ethylene carbonate, propylene carbonate, and fluoroethylene carbonate; diether compounds of polyhydric alcohols such as ethylene glycol dimethyl ether and diethylene glycol dimethyl ether; and monohydric alcohols such as methanol, ethanol, and propanol.

[0029] The electrolytic solution may contain a solute, such as an acid component such as an organic acid, an inorganic acid, or a complex acid compound of an organic acid and an inorganic acid; a base component such as an amine or a quaternary ammonium salt; a salt of an acid and a base; a nitro compound; or a phenol compound.

[0030] Furthermore, the dielectric layer provided on the surface of the anode foil 12A contains an oxide of a valve metal. The solid electrolyte layer may be formed so as to cover at least a portion of the dielectric layer. The solid electrolyte layer contains a conductive polymer component. For example, the solid electrolyte layer is formed by attaching the conductive polymer component to at least a portion of the surface of the dielectric layer. The conductive polymer component may further contain an additive, if necessary. The conductive polymer component may be attached to the surface of the separator 18.

[0031] The conductive polymer component includes, for example, a conjugated polymer component. Examples of the conjugated polymer component include π-conjugated polymer components. Examples of the conjugated polymer component include polymer components having a basic skeleton of polypyrrole, polythiophene, polyaniline, polyfuran, polyacetylene, polyphenylene, polyphenylene vinylene, polyacene, and polythiophene vinylene. One type of conjugated polymer component may be used alone, or two or more types may be used in combination.

[0032] In this embodiment, a separator 18 is disposed between the anode foil 12A and the cathode foil 12B. The separator 18 may be made of, for example, a nonwoven fabric containing fibers of cellulose, polyethylene terephthalate, vinylon, or polyamide (e.g., aliphatic polyamide, aromatic polyamide such as aramid).

[0033] (Case) The case 20 is a member that contains the capacitor element 10 and the liquid component. The case 20 has a housing 21 and a sealing body 30.

[0034] (Housing) The housing 21 has a rectangular parallelepiped shape and has an opening 24 formed over the entirety of one surface (for example, the bottom surface).

[0035] The housing 21 has a bottom surface 22 and side surfaces 23 that protrude from the edges of the bottom surface 22. The bottom surface 22 has a rectangular (more specifically, square) shape in a plan view. The side surfaces 23 protrude in one direction (e.g., downward) from the edges of the bottom surface 22 along the normal direction of the bottom surface 22.

[0036] Examples of materials that can be used to form the housing 21 include aluminum, stainless steel, copper, iron, brass, and alloys of these.

[0037] (Sealing Body) The sealing body 30 is a member that closes the opening 24 of the housing 21. The sealing body 30 includes a metal sealing plate 31 and sealing rubbers 40 that are attached to two first through holes 32 provided in the sealing plate 31, respectively.

[0038] The sealing plate 31 is a metal plate having a rectangular (square) shape in a plan view. The sealing plate 31 is formed to a size that allows it to fit into the opening 24 of the housing 21. Examples of materials that can be used to form the sealing plate 31 include aluminum, stainless steel, copper, iron, brass, and alloys of these.

[0039] The sealing plate 31 has two first through holes 32 arranged side by side in the left-right direction, penetrating the sealing plate 31 in the thickness direction (vertical direction). One sealing rubber 40 is attached to each of the two first through holes 32.

[0040] As described above, the sealing rubber 40 includes the first portion 41 and the second portion 42. The sealing rubber 40 further includes the third portion 43.

[0041] The second part 42 is cylindrical and is inserted into the first through-hole 32. The first part 41 is provided at a first end in the axial direction of the second part 42, and the third part 43 is provided at a second end in the axial direction of the second part 42.

[0042] The first portion 41 has a donut-like (annular) shape in a plan view and protrudes radially from the first end of the second portion 42. The outer diameter of the first portion 41 is set to be larger than the inner diameter of the first through hole 32. The first portion 41 of the sealing rubber 40 is disposed between the lead terminal connection portion 15 and the sealing plate 31. The thickness of the first portion 41 (the dimension in the direction in which the lead terminal connection portion 15 and the sealing plate 31 face each other) before the electrolytic capacitor 1 is assembled (before the opening 24 of the housing 21 is sealed with the sealing body 30) is set to be slightly larger than the gap that will form between the lead terminal connection portion 15 of the current collector plate 13 and the sealing plate 31 when the electrolytic capacitor 1 is assembled (after the opening 24 of the housing 21 is sealed with the sealing body 30).

[0043] The third portion 43 has a donut shape in a plan view and protrudes radially from the second end of the second portion 42. The outer diameter of the third portion 43 is set to be larger than the inner diameter of the first through hole 32.

[0044] The first portion 41, the second portion 42, and the third portion 43 are integrally molded from resin, and the sealing rubber 40 is provided with a second through-hole 44 that passes through the sealing rubber 40 in the up-down direction. The inner diameter of the second through-hole 44 is set to be slightly smaller than the outer diameter of the lead terminal 16. Therefore, the second portion 42 of the sealing rubber 40 holds the lead terminal 16 with the lead terminal 16 in close contact with the inner surface of the second through-hole 44. The material of the sealing rubber 40 is, for example, butyl rubber. However, the material of the sealing rubber 40 is not limited to butyl rubber, and may be nitrile rubber, fluororubber, silicone rubber, or the like.

[0045] The sealing rubber 40 is press-fitted and fixed into the first through hole 32 of the sealing plate 31. When the sealing rubber 40 is attached to the sealing plate 31, the second portion 42 of the sealing rubber 40 is inserted into the first through hole 32. The first portion 41 is in contact with the surface of the sealing plate 31 facing the current collector plate 13 (top surface), and the third portion 43 is in contact with the surface of the sealing plate 31 opposite the surface facing the current collector plate 13 (bottom surface). That is, each of the multiple sealing rubbers 40 further has the third portion 43 that protrudes outward from the sealing plate 31. The outer diameter (diameter) of the second portion 42 is slightly larger than the inner diameter (diameter) of the first through hole 32. Therefore, when the sealing rubber 40 is attached to the sealing plate 31, the second portion 42 is pressed inward by the inner surface of the first through hole 32. Here, the difference between the outer diameter of the second portion 42 and the inner diameter of the second through hole 44 before the sealing rubber 40 is attached to the sealing plate 31 is made slightly larger than the difference between the inner diameter of the first through hole 32 and the outer diameter of the lead terminal 16. Therefore, the second portion 42 of the sealing rubber 40 is compressed between the inner surface of the first through hole 32 and the lead terminal 16, maintaining the airtightness of the first through hole 32.

[0046] With the sealing body 30 fitted into the opening 24 of the housing 21, the sealing body 30 and the housing 21 are joined together by, for example, laser welding. That is, with the sealing body 30 fitted into the opening 24 of the housing 21, the sealing body 30 and the housing 21 are joined together. Note that in this embodiment, "joining" means joining two members together. The method for joining the sealing body 30 and the housing 21 is not limited to laser welding, and any appropriate joining method may be used.

[0047] (Current Collector Plates) A ​​plurality of electrode units 11 are respectively connected to the plurality of current collector plates 13. In this embodiment, the plurality of current collector plates 13 include a first current collector plate 13A connected to the anode unit 11A and a second current collector plate 13B connected to the cathode unit 11B.

[0048] Each of the multiple current collecting plates 13 has an electrode connection portion 14 facing the side surface portion 23 of the housing 21 and a lead terminal connection portion 15 facing the sealing plate 31. Here, the surface of the lead terminal connection portion 15 facing the sealing plate 31 is the surface of the current collecting plate 13 facing the sealing plate 31.

[0049] The electrode connection portion 14 is formed in a rectangular shape in a side view. The anode portions 11A of the plurality of anode foils 12A are connected to the electrode connection portion 14 of the first current collector plate 13A by, for example, laser welding. The cathode portions 11B of the plurality of cathode foils 12B are connected to the electrode connection portion 14 of the second current collector plate 13B by, for example, laser welding.

[0050] The lead terminal connection portion 15 has a rectangular shape when viewed from above, and protrudes from the lower end of the electrode connection portion 14 in the normal direction of the electrode connection portion 14. A first lead terminal 16A protrudes downward from the lower surface of the lead terminal connection portion 15 of the first current collector plate 13A, and a second lead terminal 16B protrudes downward from the lower surface of the lead terminal connection portion 15 of the second current collector plate 13B. In other words, each of the multiple lead terminals 16 protrudes from the lead terminal connection portion 15.

[0051] The material of the current collector plate 13 is, for example, a metal such as aluminum, stainless steel, or copper, or an alloy thereof. In this embodiment, an L-shaped current collector plate 13 having an electrode connection portion 14 and a lead terminal connection portion 15 is produced by bending a thin metal plate, for example, at a right angle. The shape of the current collector plate 13 is not limited to the above-mentioned shape, and the shape of the current collector plate 13 can be changed as appropriate as long as the lead terminal 16 protrudes from the surface facing the sealing plate 31.

[0052] (Lead Terminals) The plurality of lead terminals 16 are each formed into a round bar shape from a metal material and include a first lead terminal 16A electrically connected to the anode portion 11A and a second lead terminal 16B electrically connected to the cathode portion 11B.

[0053] The first lead terminal 16A protrudes downward from the lead terminal connection portion 15 of the first current collector plate 13A. The second lead terminal 16B protrudes downward from the lead terminal connection portion 15 of the second current collector plate 13B.

[0054] The first lead terminal 16 A is inserted into the second through-hole 44 of the sealing rubber 40 fitted into the first through-hole 32 on the left side of the sealing plate 31 , and is exposed to the outside of the case 20 through the second through-hole 44 .

[0055] The second lead terminal 16B is inserted into the second through-hole 44 of the sealing rubber 40 fitted into the first through-hole 32 on the left side of the sealing plate 31 , and is exposed to the outside of the case 20 through the second through-hole 44 .

[0056] (Seat Plate Member) The electrolytic capacitor 1 further includes a seat plate 50. The seat plate member 3 is used to make the capacitor body 2 a surface-mounted component. The seat plate member 3 is, for example, a molded product made of synthetic resin.

[0057] The seat plate member 3 includes a rectangular seat plate 50 on which the capacitor body 2 is placed, and four guide walls 51 protruding upward from four corners of the seat plate 50. The capacitor body 2 is placed on one surface (e.g., the upper surface) of the seat plate 50.

[0058] The seat plate 50 has a plurality of terminal insertion holes 52 into which the plurality of lead terminals 16 are respectively inserted. The holes 52 penetrate the seat plate 50 in the vertical direction. The seat plate 50 is provided with two terminal insertion holes 52 into which two lead terminals 16 protruding downward from the underside of the sealing body 30 are respectively inserted. The two terminal insertion holes 52 are provided so as to penetrate the seat plate 50 in the vertical direction. The two terminal insertion holes 52 are provided side by side in the left-right direction, and the terminal insertion hole 52 into which the first lead terminal 16A is inserted may be referred to as the first terminal insertion hole 52A, and the terminal insertion hole 52 into which the second lead terminal 16B is inserted may be referred to as the second terminal insertion hole 52B.

[0059] A fitting recess 53 is provided around the terminal insertion hole 52 on a surface 50A of the base plate 50 facing the sealing body 30 (for example, the upper surface in this embodiment). The fitting recess 53 has a circular shape in a top view that is concentric with the terminal insertion hole 52 and has a larger diameter than the terminal insertion hole 52. The third portion 43 of the sealing rubber 40 is inserted into the fitting recess 53. The inner diameter of the fitting recess 53 is set to be slightly smaller than the outer dimension of the third portion 43 of the sealing rubber 40.

[0060] Four guide walls 51 protruding upward from four corners are provided on the surface 50A of the seat plate 50 facing the sealing body 30. The four guide walls 51 are generally L-shaped in top view and extend along the corners of the case 20. Therefore, when the capacitor body 2 is attached to the seat plate member 3, the four guide walls 51 support the side surface 23 of the case 20, thereby suppressing vibration of the capacitor body 2.

[0061] Furthermore, a surface 50B of the seat plate 50 opposite the opposing surface 50A is provided with a plurality of grooves 54 that are connected to the plurality of terminal insertion holes 52, respectively. The grooves 54 receive the bent portions 17A, 17B of the lead terminals 16 inserted into the terminal insertion holes 52. The plurality of grooves 54 include a first groove 54A extending leftward from the first terminal insertion hole 52A on the left side and a second groove 54B extending rightward from the second terminal insertion hole 52B on the right side. The bent portion 17A of the bent tip portion of the first lead terminal 16A that protrudes downward from the first terminal insertion hole 52A is inserted into the first groove 54A. A bent portion 17B formed by bending the tip portion of the second lead terminal 16B protruding downward from the second terminal insertion hole 52B is inserted into the second groove 54B. When the bent portions 17A, 17B of the two lead terminals 16 are inserted into the two grooves 54, the lower surfaces of the bent portions 17A, 17B are arranged parallel to the surface 50B of the seat plate 50 and are located slightly below the surface 50B of the seat plate 50. This allows the bent portions 17A, 17B of the first lead terminal 16A and the second lead terminal 16B arranged along the surface 50B of the seat plate 50 to be surface-mounted on a printed wiring board.

[0062] When the electrolytic capacitor 1 is inserted and mounted, the seat plate member 3 is not attached to the capacitor body 2, and the lead terminals 16 are used in a state where they are extended straight.

[0063] (2.2) Manufacturing Method of Electrolytic Capacitor A method of manufacturing the electrolytic capacitor 1 of this embodiment will be described. Note that the manufacturing method described below is an example, and the order of the steps may be changed, or some steps may be omitted or added.

[0064] First, capacitor element 10 is fabricated by stacking a plurality of anode foils 12A having anode portions 11A and a plurality of cathode foils 12B having cathode portions 11B with separator 18 interposed between anode foil 12A and cathode foil 12B.

[0065] With the electrode connection portion 14 of the first current collector 13A in contact with one side of the multiple anode foils 12A provided in the capacitor element 10, the multiple anode foils 12A are joined to the electrode connection portion 14 of the first current collector 13A by, for example, laser welding.

[0066] Furthermore, with the electrode connection portion 14 of the second current collector 13B in contact with one side of the plurality of cathode foils 12B provided in the capacitor element 10, the plurality of cathode foils 12B are joined to the electrode connection portion 14 of the second current collector 13B by, for example, laser welding.

[0067] Next, capacitor element 10 and first current collector plate 13A and second current collector plate 13B connected to capacitor element 10 are inserted into housing 21 through opening 24. Thereafter, lead terminals 16 are inserted into second through-holes 44 of sealing rubber 40 attached to sealing plate 31, and sealing body 30 is attached to housing 21 so that sealing body 30 closes opening 24 of housing 21. Then, contact portions between sealing body 30 and housing 21 are joined by, for example, laser welding. With sealing body 30 joined to housing 21, first portion 41 of sealing rubber 40 is compressed by lead terminal connection portion 15 of current collector plate 13 and sealing plate 31, so that first portion 41 of sealing rubber 40 can be tightly attached to lead terminal connection portion 15 and sealing plate 31. Furthermore, the outer diameter of the second portion 42 of the sealing rubber 40 is set to be larger than the inner diameter of the first through hole 32, and the inner diameter of the second through hole 44 provided in the second portion 42 is set to be smaller than the outer diameter of the lead terminal 16. Therefore, the second portion 42 of the sealing rubber 40 is compressed between the inner surface of the first through hole 32 and the lead terminal 16, and the second portion 42 of the sealing rubber 40 can be tightly attached to the inner surface of the first through hole 32 and the lead terminal 16. This reduces the amount of electrolyte contained in the case 20 that permeates the sealing rubber 40 and leaks out of the case 20, thereby improving airtightness.

[0068] The capacitor body 2 assembled as described above is placed on the opposing surface 50A of the seat plate 50 so that the first lead terminal 16A and the second lead terminal 16B are inserted into the first terminal insertion hole 52A and the second terminal insertion hole 52B of the seat plate member 3, respectively. Then, the tip portions of the first lead terminal 16A and the second lead terminal 16B exposed from the surface 50B of the seat plate 50 are bent, and the bent portion 17A of the first lead terminal 16A is inserted into the first groove 54A, and the bent portion 17B of the second lead terminal 16B is inserted into the second groove 54B. At this time, the seat plate 50 is sandwiched between the bent portions 17A and 17B of the first lead terminal 16A and the second lead terminal 16B and the sealing body 30, thereby attaching the capacitor body 2 to the seat plate member 3. The third portion 43 of the sealing rubber 40 is inserted into the fitting recess 53 of the seat plate 50. The outer diameter of the third portion 43 is set to be slightly larger than the inner diameter of the fitting recess 53, so that the third portion 43 is disposed in a compressed state on the inner surface of the fitting recess 53. This further reduces the amount of electrolyte contained in the case 20 that permeates the sealing rubber 40 and leaks out of the case 20, thereby further improving the airtightness.

[0069] The electrolytic capacitor 1 of this embodiment is attached to a printed wiring board by surface-mounting the bent portions 17A, 17B of the first lead terminal 16A and the second lead terminal 16B on the printed wiring board.

[0070] When the electrolytic capacitor 1 is insert-mounted, the electrolytic capacitor 1 does not include the seat plate member 3, and is inserted and mounted with the underside of the case 20 facing the printed wiring board. In this case, the third portion 43 of the sealing rubber 40 comes into contact with the printed wiring board, which has the advantage of suppressing the transmission of vibrations to the electrolytic capacitor 1 and improving the reliability of the electrical connection of the electrolytic capacitor 1 to the printed wiring board.

[0071] (3) Modifications The above embodiment is merely one of various embodiments of the present disclosure. The above embodiment can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved.

[0072] In the above embodiment, capacitor element 10 is a laminated type, and anode foil 12A, cathode foil 12B, and separator 18 are laminated in an opposing direction DR1 in which bottom surface portion 22 of housing 21 and sealing body 30 face each other, but the stacking direction is not limited to this.

[0073] As shown in FIG. 8, anode foil 12A, cathode foil 12B, and separator 18 may be stacked in a direction DR2 that intersects with a facing direction DR1 in which bottom surface portion 22 of casing 21 and sealing body 30 face each other.

[0074] 9 , electrolytic capacitor 1 may also include another type of capacitor element 10, such as a wound type. Wound type capacitor element 10 includes anode foil 12A, cathode foil 12B, separator 18, and a conductive polymer. Anode foil 12A, cathode foil 12B, and separator 18 may be wound around a winding axis in direction DR3 that intersects with facing direction DR1 in which bottom surface portion 22 of housing 21 and sealing body 30 face each other.

[0075] In the above embodiment, the shape of the housing 21 is a rectangular cylinder with a bottom, as shown in FIG. 5 , but this is not limited to this and the housing 21 may have other shapes, such as a cylindrical shape with a bottom, depending on the location where the electrolytic capacitor 1 is to be placed, etc.

[0076] In the above embodiment, the capacitor element 10 uses both a conductive polymer and an electrolytic solution as the electrolyte, but this is not limited to this, and the electrolyte may be, for example, one of a conductive polymer and an electrolytic solution.

[0077] Furthermore, the shape of the sealing rubber 40 is not limited to the above shape and can be modified as appropriate. For example, as shown in Fig. 10, the sealing body 30 may have a sealing rubber 40A including a first portion 41 and a cylindrical second portion 42 that is longer than the thickness of the sealing plate 31. A protrusion 45 is provided around the entire periphery of the surface of the second portion 42, and when the sealing rubber 40A is attached to the sealing plate 31, the sealing plate 31 is held between the first portion 41 and the protrusion 45.

[0078] Furthermore, as shown in FIG. 11 , the sealing body 30 may have a sealing rubber 40B that includes a first portion 41 and a second portion 42 that has a truncated cone shape and whose diameter increases with increasing distance from the first portion 41.

[0079] 12, the sealing body 30 may have a sealing rubber 40C that includes a first portion 41, a second portion 42, and a truncated cone-shaped third portion 43. The third portion 43 is formed in a truncated cone shape such that the diameter decreases with increasing distance from the first portion 41. When the sealing rubber 40C is attached to the sealing plate 31, the sealing plate 31 is held between the first portion 41 and the third portion 43 (see FIG. 13).

[0080] (Summary) The above-described embodiments and the like disclose the following aspects.

[0081] The electrolytic capacitor (1) of the first aspect includes a capacitor element (10) including a plurality of electrode portions (11), a plurality of current collector plates (13), a plurality of lead terminals (16), and a case (20). The current collector plates (13) are connected to the plurality of electrode portions (11), respectively. The lead terminals (16) are connected to the current collector plates (13). The case (20) houses the capacitor element (10) and the plurality of current collector plates (13). The case (20) includes a housing (21) having an opening (24) and a sealing body (30) that closes the opening (24) of the housing (21). The sealing body (30) includes a metal sealing plate (31) having a first through hole (32) and a sealing rubber (40) that fits into the first through hole (32). The lead terminal (16) protrudes from the surface of the current collector plate (13) facing the sealing plate (31) and is inserted into a second through-hole (44) provided in the sealing rubber (40), with a portion of the lead terminal (16) exposed to the outside of the case (20). The sealing rubber (40) has a first portion (41) and a second portion (42). The first portion (41) is larger than the first through-hole (32) and is disposed between the current collector plate (13) and the sealing plate (31) in a state compressed by the current collector plate (13) and the sealing plate (31). The second portion (42) is inserted into the first through-hole (32).

[0082] According to this embodiment, the area of ​​the portion sealed by the sealing rubber (40) can be made smaller than when the entire opening (24) of the housing (21) is sealed with rubber, thereby reducing the amount of volatilized electrolyte that permeates the rubber and leaks out of the case (20). Furthermore, the sealing rubber (40) is attached to the sealing plate (31) with the first portion (41) compressed between the current collector plate (13) and the sealing plate (31). Therefore, since the sealing rubber (40) is attached to the sealing plate (31) without being chemically bonded to the sealing plate (31), an electrolytic capacitor (1) with improved airtightness can be provided while suppressing a decrease in productivity.

[0083] The electrolytic capacitor (1) of the second aspect is the same as that of the first aspect, but has a liquid component housed in the case (20). The liquid component is impregnated into the capacitor element (10).

[0084] According to this aspect, as in the first aspect, it is possible to provide an electrolytic capacitor (1) with improved airtightness while suppressing a decrease in productivity.

[0085] In the electrolytic capacitor (1) of the third aspect, in the first or second aspect, the housing (21) has a bottom surface (22) and a side surface (23) protruding from an edge of the bottom surface (22). The current collecting plate (13) has an electrode connection portion (14) facing the side surface (23) and a lead terminal connection portion (15) facing the sealing plate (31). The lead terminal (16) protrudes from the lead terminal connection portion (15). The first portion (41) of the sealing rubber (40) is disposed between the lead terminal connection portion (15) and the sealing plate (31).

[0086] According to this aspect, as in the first aspect, it is possible to provide an electrolytic capacitor (1) with improved airtightness while suppressing a decrease in productivity.

[0087] In the electrolytic capacitor (1) of the fourth aspect, in any one of the first to third aspects, the sealing body (30) and the housing (21) are joined together with the sealing body (30) fitted into the opening (24) of the housing (21).

[0088] According to this aspect, as in the first aspect, it is possible to provide an electrolytic capacitor (1) with improved airtightness while suppressing a decrease in productivity.

[0089] In the electrolytic capacitor (1) of the fifth aspect, in any one of the first to fourth aspects, the sealing rubber (40) further has a third portion (43) protruding outward from the sealing plate (31).

[0090] According to this aspect, as in the first aspect, it is possible to provide an electrolytic capacitor (1) with improved airtightness while suppressing a decrease in productivity.

[0091] The electrolytic capacitor (1) of a sixth aspect is the fifth aspect, further comprising a seat plate (50) to which the case (20) is attached. The seat plate (50) has terminal insertion holes (52) into which lead terminals (16) are inserted. A fitting recess (53) is provided around the terminal insertion hole (52) on a surface (50A) of the seat plate (50) facing the sealing body (30). A third portion (43) of the sealing rubber (40) fits into the fitting recess (53).

[0092] According to this aspect, the third portion (43) is fitted into the fitting recess (53), thereby further improving the airtightness.

[0093] In the electrolytic capacitor (1) of the seventh aspect, in the sixth aspect, a groove (54) connected to the terminal insertion hole (52) is provided on the surface (50B) opposite to the opposing surface (50A) of the base plate (50). The bent portion of the lead terminal (16) passed through the terminal insertion hole (52) is inserted into the groove (54).

[0094] According to this aspect, the electrolytic capacitor (1) can be surface mounted.

[0095] In an eighth aspect of the electrolytic capacitor (1), in any one of the first to seventh aspects, the plurality of electrode portions (11) include an anode portion (11A) and a cathode portion (11B). The capacitor element (10) includes an anode foil (12A) including the anode portion (11A), a cathode foil (12B) including the cathode portion (11B), and a separator (18) and a conductive polymer disposed between the anode foil (12A) and the cathode foil (12B). The anode foil (12A), the cathode foil (12B), and the separator (18) are stacked in a facing direction (DR1) in which a bottom surface portion (22) of the housing (21) and a sealing body (30) face each other.

[0096] According to this aspect, as in the first aspect, it is possible to provide an electrolytic capacitor (1) with improved airtightness while suppressing a decrease in productivity.

[0097] In a ninth aspect of the electrolytic capacitor (1), in any one of the first to seventh aspects, the plurality of electrode portions (11) include an anode portion (11A) and a cathode portion (11B). The capacitor element (10) includes an anode foil (12A) including the anode portion (11A), a cathode foil (12B) including the cathode portion (11B), and a separator (18) and a conductive polymer disposed between the anode foil (12A) and the cathode foil (12B). The anode foil (12A), the cathode foil (12B), and the separator (18) are stacked in a direction (DR2) intersecting a facing direction (DR1) in which a bottom surface portion (22) of the housing (21) and a sealing body (30) face each other.

[0098] According to this aspect, as in the first aspect, it is possible to provide an electrolytic capacitor (1) with improved airtightness while suppressing a decrease in productivity.

[0099] In a tenth aspect of the electrolytic capacitor (1), in any one of the first to seventh aspects, the plurality of electrode portions (11) include an anode portion (11A) and a cathode portion (11B). The capacitor element (10) includes an anode foil (12A) including the anode portion (11A), a cathode foil (12B) including the cathode portion (11B), and a separator (18) and a conductive polymer disposed between the anode foil (12A) and the cathode foil (12B). The anode foil (12A), the cathode foil (12B), and the separator (18) are wound around a winding axis in a direction (DR3) intersecting a facing direction (DR1) in which a bottom surface portion (22) of the housing (21) and a sealing body (30) face each other.

[0100] According to this aspect, as in the first aspect, it is possible to provide an electrolytic capacitor (1) with improved airtightness while suppressing a decrease in productivity.

[0101] The configurations according to the second to tenth aspects are not essential for the electrolytic capacitor (1) and can be omitted as appropriate.

[0102] REFERENCE SIGNS LIST 1 electrolytic capacitor 10 capacitor element 11 electrode portion 11A anode portion 11B cathode portion 12A anode foil 12B cathode foil 13 current collector plate 14 electrode connection portion 15 lead terminal connection portion 16 lead terminal 18 separator 20 case 21 housing 22 bottom surface portion 23 side surface portion 24 opening 30 sealing body 31 sealing plate 32 first through hole 40 sealing rubber 41 first portion 42 second portion 43 third portion 44 second through hole 50 seat plate 50A opposing surface 50B surface 52 terminal insertion hole 53 fitting recess 54 groove DR1 opposing direction DR2 direction DR3 direction

Claims

1. An electrolytic capacitor comprising: a capacitor element including a plurality of electrode portions; current collecting plates connected to each of the plurality of electrode portions; lead terminals connected to the current collecting plates; and a case accommodating the capacitor element and the current collecting plates, wherein the case has a housing with an opening and a sealing body closing the opening of the housing, the sealing body having a metal sealing plate with a first through hole formed therein, and a sealing rubber fitting into the first through hole, wherein the lead terminals protrude from a surface of the current collecting plate facing the sealing plate and are inserted into second through holes formed in the sealing rubber, with portions of the lead terminals exposed to the outside of the case, and the sealing rubber having: a first portion larger than the first through hole and positioned between the current collecting plate and the sealing plate in a state compressed by the current collecting plate and the sealing plate; and a second portion inserted into the first through hole.

2. The electrolytic capacitor according to claim 1, further comprising a liquid component housed in the case, the liquid component being impregnated into the capacitor element.

3. The electrolytic capacitor according to claim 1, wherein the housing has a bottom surface and a side surface protruding from an edge of the bottom surface, the current collecting plate has an electrode connection portion facing the side surface and a lead terminal connection portion facing the sealing plate, the lead terminals protrude from the lead terminal connection portion, and the first portion of the sealing rubber is positioned between the lead terminal connection portion and the sealing plate.

4. The electrolytic capacitor according to claim 1, wherein the sealing body and the housing are joined together in a state where the sealing body is fitted into the opening of the housing.

5. The electrolytic capacitor according to claim 1, wherein the sealing rubber further has a third portion that protrudes outward from the sealing plate.

6. The electrolytic capacitor according to claim 5, further comprising a seat plate to which the case is attached, the seat plate having terminal insertion holes into which the lead terminals are inserted, a mating recess formed around the terminal insertion hole on the surface of the seat plate facing the sealing body, and the third portion of the sealing rubber mating with the mating recess.

7. The electrolytic capacitor according to claim 6, wherein a groove connected to the terminal insertion hole is provided on the surface of the seat plate opposite to the opposing surface, and a bent portion of the lead terminal passed through the terminal insertion hole is inserted into the groove.

8. The electrolytic capacitor according to claim 1, wherein the plurality of electrode portions include an anode portion and a cathode portion, the capacitor element includes an anode foil including the anode portion, a cathode foil including the cathode portion, and a separator and a conductive polymer disposed between the anode foil and the cathode foil, and the anode foil, the cathode foil, and the separator are stacked in an opposing direction in which the bottom surface of the casing and the sealing body face each other.

9. The electrolytic capacitor according to claim 1, wherein the plurality of electrode portions include an anode portion and a cathode portion, the capacitor element includes an anode foil including the anode portion, a cathode foil including the cathode portion, and a separator and a conductive polymer disposed between the anode foil and the cathode foil, and the anode foil, the cathode foil, and the separator are stacked in a direction intersecting a direction in which the bottom surface of the casing and the sealing body face each other.

10. The electrolytic capacitor according to claim 1, wherein the plurality of electrode portions include an anode portion and a cathode portion, the capacitor element includes an anode foil including the anode portion, a cathode foil including the cathode portion, and a separator and a conductive polymer disposed between the anode foil and the cathode foil, and the anode foil, the cathode foil, and the separator are wound around a winding axis that intersects with the opposing direction between the bottom surface of the casing and the sealing body.

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