Electrolytic capacitor and method for manufacturing same

Abstract

This electrolytic capacitor comprises: a capacitor element including a positive electrode part and a negative electrode part; and a case for accommodating the capacitor element. The case has: a housing having an opening; and a sealing body for closing the opening of the housing. The sealing body includes: a lead part composed of a positive electrode lead section and a negative electrode lead section; a frame part surrounding the lead part; and a sealing resin part filling a space between the lead part and the frame part. The positive electrode part of the capacitor element is joined to the positive electrode lead section, and the negative electrode part of the capacitor element is joined to the negative electrode lead section.

Description

Electrolytic capacitor and its manufacturing method

[0001] The present disclosure relates to an electrolytic capacitor and a method for manufacturing an electrolytic capacitor, and more particularly to an electrolytic capacitor including a capacitor element and a method for manufacturing the electrolytic capacitor.

[0002] Patent Document 1 discloses a solid electrolytic capacitor including a capacitor element having an anode body including a dielectric layer and a solid electrolyte layer covering at least a portion of the dielectric layer, an exterior resin covering the capacitor element, and a coating layer located between the capacitor element and the exterior resin and containing a fluorine compound.

[0003] International Publication No. 2019 / 230591

[0004] An electrolytic capacitor according to one aspect of the present disclosure includes a capacitor element including an anode portion and a cathode portion, and a case that houses the capacitor element, wherein the case has a housing with an opening and a sealing body that closes the opening of the housing, the sealing body including a lead portion consisting of an anode lead portion and a cathode lead portion, a frame portion that surrounds the lead portions, and a sealing resin portion that fills the space between the lead portions and the frame portion, and the anode portion of the capacitor element is joined to the anode lead portion, and the cathode portion of the capacitor element is joined to the cathode lead portion.

[0005] A method for manufacturing an electrolytic capacitor according to one aspect of the present disclosure includes the steps of: preparing a capacitor element including an anode portion and a cathode portion; a housing having an opening; a sealing body including a lead portion consisting of an anode lead portion and a cathode lead portion; a frame portion surrounding the lead portion; and a sealing resin portion filling the space between the lead portion and the frame portion; joining the anode lead portion of the sealing body to the anode portion of the capacitor element and joining the cathode lead portion of the sealing body to the cathode portion of the capacitor element; arranging the sealing body to which the capacitor element is joined so as to accommodate the capacitor element within the housing and to close the opening of the housing; and sealing the opening of the housing by welding the sealing body to the opening.

[0006] According to the present disclosure, the airtightness of an electrolytic capacitor can be improved.

[0007] Fig. 1 is a schematic perspective view of an electrolytic capacitor according to an embodiment of the present disclosure. Fig. 2 is a schematic cross-sectional view of an electrolytic capacitor according to an embodiment of the present disclosure taken along line X-X in Fig. 1. Fig. 3 is a schematic exploded view of an electrolytic capacitor according to an embodiment of the present disclosure. Fig. 4 is a schematic perspective view showing an example of a lead portion in an electrolytic capacitor. Fig. 5 is a schematic perspective view showing a method of joining the lead portion to an anode foil and a cathode foil by laser welding.

[0008] In the electrolytic capacitor disclosed in Patent Document 1, the conductive polymer of the capacitor element is deteriorated due to the penetration of external moisture and oxygen through the exterior resin. However, the coating layer prevents external moisture and oxygen from reaching the conductive polymer, but this is not sufficient. Thus, electrolytic capacitors are required to have improved airtightness to prevent the penetration of external moisture and oxygen.

[0009] The present disclosure provides an electrolytic capacitor and a method for manufacturing an electrolytic capacitor that can improve airtightness.

[0010] (Embodiments) (1) Overview Electrolytic capacitors according to embodiments will be described below with reference to the drawings. However, the following embodiment is merely one of various embodiments of the present disclosure. The following embodiment can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. Furthermore, each figure described in the following embodiments is a schematic diagram, and the ratios of the sizes and thicknesses of the components in the figures do not necessarily reflect the actual dimensional ratios.

[0011] As shown in FIGS. 1 to 3, the electrolytic capacitor 1 of this embodiment includes a capacitor element 10 and a case 20.

[0012] The case 20 has a housing 21 having an opening 211 and a sealing body 22 that closes the opening 211 of the housing 21 .

[0013] Sealing body 22 includes a lead portion 31, a frame portion 32 surrounding lead portion 31, and a sealing resin portion 33 filling the space between lead portion 31 and frame portion 32. Lead portion 31 is made up of an anode lead portion 31A and a cathode lead portion 31B.

[0014] Capacitor element 10 includes an anode portion 11 A and a cathode portion 11 B. Anode portion 11 A of capacitor element 10 is joined to an anode lead portion 31 A. Cathode portion 11 B of capacitor element 10 is joined to a cathode lead portion 31 B.

[0015] In the electrolytic capacitor 1 of this embodiment, the case 20 includes a housing 21 and a sealing body 22. The sealing body 22, which closes the opening of the housing 21, is composed of a lead portion 31, a frame portion 32, and a sealing resin portion 33. Therefore, compared to conventional electrolytic capacitors in which the opening is sealed with a resin such as rubber, materials with low gas permeability can be used for the lead portion 31, the frame portion 32, and the sealing resin portion 33, thereby improving the airtightness of the electrolytic capacitor. In particular, the sealing resin portion 33 is made of a material with lower gas permeability than the resin such as rubber used in conventional electrolytic capacitors, and is formed so as to fill the gap between the metal lead portion 31 and the frame portion 32. This increases the adhesion between the lead portion 31 and the sealing resin portion 33 and between the frame portion 32 and the sealing resin portion 33, which is believed to significantly improve the airtightness compared to conventional electrolytic capacitors.

[0016] The electrolytic capacitor 1 of this embodiment has improved airtightness, which reduces the intrusion of moisture and oxygen from the outside and suppresses deterioration of the conductive polymer and other components of the capacitor element 10. This improves the reliability of the electrolytic capacitor 1. Furthermore, in an electrolytic capacitor 1 that contains a liquid component such as an electrolyte solution inside, evaporation of the liquid component to the outside can be reduced, suppressing the reduction of the liquid component and lengthening the time until the liquid component disappears (dries up) from the capacitor element 10. Because the liquid component has a repair function for the dielectric layer of the capacitor element 10, extending the time the capacitor element 10 retains the liquid component improves the reliability of the electrolytic capacitor 1.

[0017] (2) Details <Electrolytic Capacitor> The configuration of the electrolytic capacitor 1 according to this embodiment will be described in more detail below. In this embodiment, as a representative example, the electrolytic capacitor 1 will be described as a hybrid electrolytic capacitor 1 that includes both a solid electrolyte such as a conductive polymer and a liquid component such as an electrolytic solution as the electrolyte.

[0018] 2 includes a capacitor element 10 and a case 20. Capacitor element 10 is impregnated with a liquid component (not shown).

[0019] [Capacitor Element] As shown in FIG. 2, the capacitor element 10 is housed in a case 20. The capacitor element 10 includes an anode portion 11A and a cathode portion 11B. For example, as shown in FIG. 5, the capacitor element 10 includes an anode foil 12A including the anode portion 11A and a cathode foil 12B including the cathode portion 11B. A separator 13 is disposed between the anode foil 12A and the cathode foil 12B, and a conductive polymer is disposed as a solid electrolyte. Examples of conductive polymers include polypyrrole, polythiophene, poly(3,4-ethylenedioxythiophene) (PEDOT), and polyaniline. Examples of materials for the separator 13 include cellulose, polyethylene terephthalate (PET), vinylon, and aramid fiber. The separator 13 may be formed by sandwiching a sheet between the anode foil 12A and the cathode foil 12B, or by folding a long sheet between the anode foil 12A and the cathode foil 12B. The separator 13 can hold an electrolyte such as an electrolytic solution or a conductive polymer by being impregnated therein.

[0020] 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 cathode foil 12B is a metal foil containing a valve metal such as aluminum, tantalum, or niobium.

[0021] 2 and 3 includes a stacked capacitor element 10 as the capacitor element 10. As shown in Figures 2, 3, and 5, the stacked capacitor element 10 is formed by stacking, for example, an anode foil 12A, a cathode foil 12B, and a separator 13 in a direction from the bottom surface of the housing 21 toward the opening 211.

[0022] The anode portion 11A of the capacitor element 10 is joined to an anode lead portion 31A of the lead portion 31 described below. The cathode portion 11B of the capacitor element 10 is joined to a cathode lead portion 31B. "Joining" means joining two members together. Examples of joining methods that can be used include laser welding, ultrasonic welding, and resistance welding. These joining methods allow the lead portions 31A and 31B to be electrically and mechanically connected to the anode portion 11A and the cathode portion 11B.

[0023] [Case] ​​The case 20 accommodates the capacitor element 10 and the liquid component. As shown in FIGS.

[0024] (Housing) The housing 21 is a member having an opening 211, and the shape of the housing 21 is usually a hollow cube or rectangular parallelepiped with a bottomed square cylinder that is open on one face.

[0025] The material of the housing 21 is usually a metal, such as aluminum, stainless steel, copper, iron, brass, or an alloy of these.

[0026] (Sealing Body) The sealing body 22 is a member that closes the opening 211 of the housing 21. The sealing body 22 includes a lead portion 31, a frame portion 32, and a sealing resin portion 33.

[0027] (Lead Portion) Lead portion 31 is composed of anode lead portion 31A and cathode lead portion 31B, and is a member that serves as a current collector by having a portion of its surface exposed to the outside of case 20. This current collector is joined by solder or the like to a substrate on which electrolytic capacitor 1 is mounted. Lead portion 31 is typically made of a metal, such as aluminum, stainless steel, copper, iron, brass, or an alloy thereof.

[0028] The lead portions 31A and 31B preferably have a shape including a flat surface for connection with the mounting board, such as a simple flat plate shape or an L-shaped plate shape.

[0029] 2, lead portions 31A, 31B typically protrude from sealing body 22 toward the inside of casing 21. Anode lead portion 31A is joined to anode portion 11A of capacitor element 10 and is electrically connected to anode foil 12A via anode portion 11A. Cathode lead portion 31B is joined to cathode portion 11B of capacitor element 10 and is electrically connected to cathode foil 12B via cathode portion 11B.

[0030] 2 and 3, each of the lead portions 31A, 31B may be a single flat-plate-shaped member, or may include an inner lead portion 311 facing the inside of the housing 21 and an outer lead portion 312 located on the opposite side of the inner lead portion 311, as shown in Fig. 4. Such lead portions 31A, 31B can be fabricated by joining the flat-plate-shaped member of the inner lead portion 311 and the flat-plate-shaped member of the outer lead portion 312 by, for example, welding. In such lead portions 31A, 31B, the inner lead portion 311 and the outer lead portion 312 can be made to be different in size or material. For example, if the electrical conductivity of the material of the inner lead portion 311 is lower than that of the material of the outer lead portion 312, the cross-sectional area of ​​the inner lead portion 311 (the cross-sectional area in a cross section perpendicular to the direction from the inside to the outside of the housing 21) can be made larger than the cross-sectional area of ​​the outer lead portion 312 to prevent the electrical conductivity of the entire lead portions 31A, 31B from being limited by the material with low electrical conductivity. Furthermore, the contact area between the lead portions 31A and 31B and the anode portion 11A and the cathode portion 11B can be increased, and the connection resistance can be further reduced.

[0031] It is preferable that the first metal constituting the inner lead portion 311 and the second metal constituting the outer lead portion 312 are different. In this case, the first metal is, for example, aluminum, and the second metal is, for example, copper. This allows the inner lead portion 311 to be made of the same material as the anode portion 11A and the cathode portion 11B, thereby achieving strong bonding, and allows the outer lead portion 312 to be made of a material that further improves solder connectivity. Even when the inner lead portion 311 and the outer lead portion 312 are made of different metals, the bonding interface between the inner lead portion 311 and the outer lead portion 312 is covered with the sealing resin portion 33, preventing moisture from reaching the interface from the outside, thereby suppressing the occurrence of pitting corrosion and the like. "The first metal and the second metal are different" means that the first metal and the second metal are not identical, and "the first metal and the second metal are identical" means that the compositions of the metal components contained in the first metal and the second metal are identical, i.e., the types and amounts of the metal components are the same.

[0032] Furthermore, the first metal and the second metal in the lead portion 31 may be the same. In this case, both the first metal and the second metal are, for example, aluminum. This makes it easier to join by welding between the anode portion 11A and the lead portion 31 and between the cathode portion 11B and the lead portion 31. In this case, plating the outer surface of the lead portion 31 with Ni, Sn, or the like can improve connectivity with solder.

[0033] To improve solder connectivity, the mounting surface of the outer lead portion 312 is preferably roughened or provided with irregularities by forming regular depressions. Examples of the irregular shape include stripes, a grid, and dots. The size of the irregularities is, for example, approximately 100 μm to 5 mm. The irregularities can also be formed by deformation such as knurling when joining the anode foil 12A and the cathode foil 12B or when bonding the inner lead portion 311 and the outer lead portion 312 together.

[0034] (Frame portion) The frame portion 32 is a member that surrounds the lead portion 31. That is, as shown in FIG. 1 , the frame portion 32 is disposed around the lead portion 31 with the sealing resin portion 33 interposed therebetween, and is usually disposed around the entire outer periphery of the sealing body 22.

[0035] The frame portion 32 is usually made of a metal, such as aluminum, stainless steel, copper, iron, brass, or an alloy thereof.

[0036] (Sealing Resin Portion) The sealing resin portion 33 is a member that fills the gap between the lead portion 31 and the frame portion 32. That is, as shown in Fig. 1 , the sealing resin portion 33 is formed so that there are no gaps between the anode lead portion 31A and the cathode lead portion 31B, between the anode lead portion 31A and the frame portion 32, and between the cathode lead portion 31B and the frame portion 32. The sealing resin portion 33 is formed so that there is high adhesion between the frame portion 32 and the sealing resin portion 33, and between the lead portion 31 and the sealing resin portion 33.

[0037] Thermoplastic resins are typically used as the material for the sealing resin portion 33 because they can be injection molded. Among these, polybutylene terephthalate (PBT) and polyphenylene sulfide (PPS) are preferred. These resins have particularly low gas permeability, which can further improve the airtightness of the electrolytic capacitor 1. Furthermore, their high heat resistance further improves reliability in high-temperature environments.

[0038] In the sealing body 22, it is preferable that the surfaces of the lead portions 31 that come into contact with the sealing resin portion 33 and the surfaces of the frame portion 32 that come into contact with the sealing resin portion 33 are surface-treated surfaces. In other words, when producing the sealing body 22, it is preferable to surface-treat the outer surfaces of the lead portions 31, the surface of the inner lead portion 311 facing the outer lead portion 312, and the inner peripheral side surface of the frame portion 32. This improves the adhesion between the lead portions 31 and the sealing resin portion 33 and between the frame portion 32 and the sealing resin portion 33, thereby further improving the airtightness of the electrolytic capacitor 1.

[0039] Examples of surface treatments include chemical surface treatments, surface roughening treatments, or both. Chemical surface treatments include immersion in a chemical conversion solution such as an ammonium adipate solution followed by heat treatment, or immersion in a chemical conversion solution followed by application of a voltage, thereby forming a chemical conversion coating. Surface roughening can also be performed by etching, which can be performed by, for example, direct current electrolysis or alternating current electrolysis.

[0040] It is preferable that sealing body 22 be joined to opening 211 of housing 21 to seal opening 211. By joining sealing body 22 to housing 21 in this way and sealing opening 211, the gap between housing 21 and sealing body 22 can be further reduced, thereby further improving the airtightness of electrolytic capacitor 1. This joining is preferably performed by welding, from the viewpoint of further improving the airtightness.

[0041] 2, it is also preferable that the sealing resin portion 33 of the sealing body 22 protrudes into the interior of the housing 21 and fits into the opening 211 of the housing 21. With this structure, the sealing resin portion 33, which is formed thicker than the frame portion 32, matches the inner dimensions of the housing 21, making it easy to align the frame portion 32 of the sealing body 22 with the edge of the opening 211 of the housing 21. Therefore, by subsequently welding, the gap between the housing 21 and the sealing body 22 can be further reduced, further improving the airtightness of the electrolytic capacitor 1.

[0042] The sealing body 22 is preferably an integrated body of the lead portions 31, the frame portion 32, and the sealing resin portion 33. That is, the sealing body 22 is preferably formed by injection molding the sealing resin portion 33 onto the lead portions 31 and the frame portion 32, i.e., by insert molding. By using an insert-molded body as the sealing body 22 in this way, it is possible to further improve the adhesion between the lead portions 31 and the sealing resin portion 33 and between the frame portion 32 and the sealing resin portion 33, and as a result, it is possible to further improve the airtightness of the electrolytic capacitor 1.

[0043] (Liquid Component) The liquid component is impregnated into capacitor element 10. As a result, the liquid component is contained within case 20. More specifically, the liquid component is impregnated into separator 13 of capacitor element 10 and the like.

[0044] The liquid component may be, for example, an electrolyte solution.

[0045] The electrolytic solution may be an organic solvent, for example. 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.

[0046] 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.

[0047] (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 and the like as long as the object of the present disclosure can be achieved.

[0048] In the above embodiment, the electrolytic capacitor 1 is a hybrid electrolytic capacitor 1 having both a solid electrolyte and a liquid component as the electrolyte, but this is not limited to this, and the electrolytic capacitor 1 may have only one of a solid electrolyte and a liquid component.

[0049] In the above embodiment, the shape of the housing 21 is a rectangular cylinder with a bottom, as shown in FIG. 3 , but this is not limited to this, and other shapes, such as a cylindrical shape with a bottom, may be used depending on the location where the electrolytic capacitor 1 is to be mounted, etc.

[0050] In the above embodiment, a stacked type capacitor element 10 is used as capacitor element 10, but this is not limited to this, and other types of capacitor elements 10, such as a wound type, can also be used. Wound type capacitor element 10 includes anode foil 12A, cathode foil 12B, separator 13, and a conductive polymer, and anode foil 12A, cathode foil 12B, and separator 13 are wound around a winding axis that intersects with the direction from the bottom surface of housing 21 toward opening 211.

[0051] <Method for Manufacturing Electrolytic Capacitor> The electrolytic capacitor 1 of this embodiment can be simply and reliably manufactured by a manufacturing method including, for example, a preparation step, a joining step, an arrangement step, and a sealing step. When manufacturing an electrolytic capacitor 1 having an electrolyte solution inside, this manufacturing method may include an impregnation step before the sealing step. Each step will be described below.

[0052] [Preparation Step] In this step, the capacitor element 10, the housing 21, and the sealing body 22 are prepared. The sealing body 22 includes a lead portion 31, a frame portion 32, and a sealing resin portion 33. The capacitor element 10 includes an anode portion 11A and a cathode portion 11B. The housing 21 has an opening 211. The lead portion 31 is made up of an anode lead portion 31A and a cathode lead portion 31B, the frame portion 32 surrounds the lead portion 31, and the sealing resin portion 33 fills the space between the lead portion 31 and the frame portion 32. The capacitor element 10 may be either a stacked type or a wound type.

[0053] This sealing body 22 is preferably formed by injection molding the sealing resin portion 33 onto the lead portion 31 and the frame portion 32. In other words, it is preferable to place the lead portion 31 and the frame portion 32 in a mold, and then inject a resin that forms the sealing resin portion 33 to perform insert molding.

[0054] When the above-described injection molding is performed, it is preferable to perform at least one of a chemical surface treatment and a surface roughening treatment beforehand on the surfaces of the lead portions 31 and the frame portion 32 that come into contact with the sealing resin portion 33. By performing such a chemical surface treatment and a surface roughening treatment in advance on the surfaces of the lead portions 31 and the frame portion 32 that come into contact with the sealing resin portion 33 by injection molding using the above-described method, it is possible to further improve the adhesion between the lead portions 31 and the sealing resin portion 33 and between the frame portion 32 and the sealing resin portion 33, and as a result, it is possible to further improve the airtightness of the electrolytic capacitor 1.

[0055] [Bonding Step] In this step, anode lead portion 31A of sealing body 22 is joined to anode portion 11A of capacitor element 10, and cathode lead portion 31B of sealing body 22 is joined to cathode portion 11B of capacitor element 10.

[0056] Examples of joining methods include laser welding, ultrasonic welding, and resistance welding.

[0057] The joining is preferably performed by laser welding. Laser welding also allows for collective welding. First, as shown in FIG. 5 , multiple sets (e.g., 30 sets) of anode foils 12A, separators 13, and cathode foils 12B are stacked on the inner lead portion 311A ​​of the anode lead portion 31A and the inner lead portion 311B of the cathode lead portion 31B. Next, as indicated by the arrows in FIG. 5 , the uppermost anode foils 12A and cathode foils 12B are irradiated with a laser, thereby performing collective welding. This method allows for easy joining of the anode lead portion 31A to the anode portion 11A and the cathode lead portion 31B to the cathode portion 11B. Furthermore, it is possible to simultaneously join the anode portions 11A of the multiple anode foils 12A and the cathode portions 11B of the multiple cathode foils 12B. Welding eliminates connection interface resistance, which contributes to lowering the resistance of the lead portion 31 compared to conventional crimping connection methods. Furthermore, the manufacturing takt time can be reduced.

[0058] [Arrangement Step] In this step, sealing body 22 to which capacitor element 10 obtained in the joining step is joined is placed so as to accommodate capacitor element 10 in housing 21 and close opening 211 of housing 21 .

[0059] This process may be performed by recessing a portion of the inner wall of the housing 21 and storing the sealing body 22 inside, but as described above, by making the sealing resin portion 33 of the sealing body 22 protrude into the inside of the housing 21 and making it match the internal dimensions of the housing 21, it is possible to easily align the frame portion 32 of the sealing body 22 with the end of the opening 211 of the housing 21.

[0060] [Impregnation Step] In this step, the electrolyte solution is impregnated into the capacitor element 10. This step may be performed by introducing the electrolyte solution into the housing 21 that houses the capacitor element 10. Specifically, the electrolyte solution is impregnated into the separator 13 of the capacitor element 10, etc. The impregnation step may be performed before the placement step. In this case, the electrolyte solution is impregnated into the capacitor element 10 by, for example, immersing the capacitor element 10 in the electrolyte solution.

[0061] [Sealing Step] In this step, the sealing body 22 is welded to the opening 211 of the housing 21 to seal the opening 211 .

[0062] This step is performed by welding the metal of the frame portion 32 of the sealing body 22 to the metal of the edge of the opening 211 of the housing 21 .

[0063] In this manner, the electrolytic capacitor 1 with improved airtightness can be manufactured simply and reliably.

[0064] <Evaluation of sealing performance> In order to evaluate the sealing performance of the sealing body, a sealing body sample was prepared by insert-molding a metal corresponding to the lead portion with a resin, and a container containing an electrolyte solution was sealed with the sealing body sample. The amount of electrolyte lost when the container was left in this state for a long period of time was evaluated.

[0065] [Preparation of Sealing Body Samples] Sealing body samples were prepared according to the following procedure.

[0066] First, a sealing body sample was produced by insert molding, in which a sealing resin portion (made of PPS) was formed around a metal portion corresponding to a lead portion.

[0067] Next, the container containing the liquid component (electrolytic solution containing ethylene glycol) was sealed with the sealing body sample.

[0068] In this way, three samples (N1 to N3) were obtained.

[0069] [Evaluation] As an index of airtightness, the samples (N1 to N3) prepared above were kept in an environment of 145° C. and the change in mass over time (mass loss rate) was measured to determine the change in mass. The measurement results are shown in Table 1 below.

[0070]

[0071] As can be seen from the results in Table 1, the sealant samples in which the metal corresponding to the lead portions was insert-molded with resin showed very little change in mass even after 500 hours, demonstrating that sufficient airtightness was obtained. The sealant 22 of the electrolytic capacitor of this embodiment is formed by injection molding the sealing resin portion 33 onto the lead portions 31 and frame portion 32, and it is believed from the above results that sufficient airtightness is obtained.

[0072] (Summary) As is clear from the above-described embodiment and modifications, the present disclosure includes the following aspects. In the following, reference numerals are given in parentheses only to clarify the correspondence with the embodiment.

[0073] The electrolytic capacitor (1) of the first aspect includes a capacitor element (10) and a case (20). The capacitor element (10) includes an anode portion (11A) and a cathode portion (11B). The case (20) houses the capacitor element (10). The case (20) includes a housing (21) having an opening (211) and a sealing body (22) that closes the opening (211) of the housing (21). The sealing body (22) includes a lead portion (31) consisting of an anode lead portion (31A) and a cathode lead portion (31B), a frame portion (32) that surrounds the lead portion (31), and a sealing resin portion (33) that fills the space between the lead portion (31) and the frame portion (32). The anode part (11A) of the capacitor element (10) is joined to the anode lead part (31A), and the cathode part (11B) of the capacitor element (10) is joined to the cathode lead part (31B).

[0074] According to the first aspect, the electrolytic capacitor (1) can have improved airtightness.

[0075] The electrolytic capacitor (1) of the second aspect is the electrolytic capacitor (1) of the first aspect, further comprising a liquid component housed in the case (20). The liquid component is impregnated into the capacitor element (10).

[0076] According to the second aspect, the electrolytic capacitor (1) has improved airtightness, so that the decrease over time of the liquid component contained inside can be further suppressed.

[0077] In the electrolytic capacitor (1) of the third aspect, in the first or second aspect, the sealing body (22) is an integrated body of the lead portion (31), the frame portion (32), and the sealing resin portion (33).

[0078] According to the third aspect, the electrolytic capacitor (1) can further improve the airtightness.

[0079] In the electrolytic capacitor (1) of the fourth aspect, in any one of the first to third aspects, the surface of the lead portion (31) that comes into contact with the sealing resin portion (33) and the surface of the frame portion (32) that comes into contact with the sealing resin portion (33) are surface-treated surfaces.

[0080] According to the fourth aspect, the electrolytic capacitor (1) can further improve the airtightness.

[0081] In the electrolytic capacitor (1) of the fifth aspect, in any one of the first to fourth aspects, the sealing body (22) is joined to the opening (211) of the housing (21) to seal the opening (211).

[0082] According to the fifth aspect, the electrolytic capacitor (1) can have further improved airtightness.

[0083] In the electrolytic capacitor (1) of the sixth aspect, in any one of the first to fifth aspects, the sealing resin portion (33) of the sealing body (22) protrudes into the housing (21). The sealing resin portion (33) is fitted into the opening (211).

[0084] According to the sixth aspect, the electrolytic capacitor (1) can facilitate alignment of the sealing body (22) with respect to the housing (21), thereby further improving airtightness.

[0085] In the electrolytic capacitor (1) of the seventh aspect, in any one of the first to sixth aspects, the lead portion (31) includes an inner lead portion (311) facing the inside of the housing (21) and an outer lead portion (312) located on the opposite side of the inner lead portion (311). The first metal constituting the inner lead portion (311) is different from the second metal constituting the outer lead portion (312).

[0086] According to the seventh aspect, the solder connectivity of the outer lead portion (312) can be improved.

[0087] In the electrolytic capacitor (1) of the eighth aspect, in any one of the first to sixth aspects, the lead portion (31) includes an inner lead portion (311) facing the inside of the housing (21) and an outer lead portion (312) located on the opposite side of the inner lead portion (311). The first metal constituting the inner lead portion (311) and the second metal constituting the outer lead portion (312) are the same.

[0088] According to the eighth aspect, the lead portion (31) can be easily produced by welding.

[0089] In a ninth aspect of the electrolytic capacitor (1), in any one of the first to eighth aspects, the capacitor element (10) includes an anode foil (12A) including an anode portion (11A), a cathode foil (12B) including a cathode portion (11B), and a separator (13) 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 (13) are stacked in a direction from the bottom surface of the housing (21) toward the opening (211).

[0090] According to the ninth aspect, the electrolytic capacitor (1) can improve airtightness even when the capacitor element (10) is a laminated type.

[0091] In a tenth aspect of the electrolytic capacitor (1), in any one of the first to eighth aspects, the capacitor element (10) includes an anode foil (12A) including an anode portion (11A), a cathode foil (12B) including a cathode portion (11B), a separator (13) 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 (13) are wound around a winding axis that intersects with a direction from the bottom surface of the housing (21) toward the opening (211).

[0092] According to the tenth aspect, the electrolytic capacitor (1) can improve airtightness even when the capacitor element (10) is of a wound type.

[0093] A method for manufacturing an electrolytic capacitor (1) according to an eleventh aspect includes a preparation step, a joining step, an arrangement step, and a sealing step. In the preparation step, a capacitor element (10) including an anode portion (11A) and a cathode portion (11B), a housing (21) having an opening (211), a lead portion (31) consisting of an anode lead portion (31A) and a cathode lead portion (31B), a frame portion (32) surrounding the lead portion (31), and a sealing resin portion (33) filling the gap between the lead portion (31) and the frame portion (32) are prepared. In the joining step, the anode lead portion (31A) of the sealing body (22) is joined to the anode portion (11A) of the capacitor element (10), and the cathode lead portion (31B) of the sealing body (22) is joined to the cathode portion (11B) of the capacitor element (10). In the arrangement step, the sealing body (22) to which the capacitor element (10) is joined is arranged so as to accommodate the capacitor element (10) in the housing (21) and to close the opening (211) of the housing (21). In the sealing step, the sealing body (22) is welded to the opening (211) of the housing (21) to seal the opening (211).

[0094] According to the eleventh aspect, an electrolytic capacitor (1) with improved airtightness can be manufactured simply and reliably.

[0095] The method for manufacturing an electrolytic capacitor (1) of the twelfth aspect is the eleventh aspect, further comprising a step of impregnating the capacitor element (10) with an electrolytic solution before the step of sealing the opening (211).

[0096] According to the twelfth aspect, the electrolytic capacitor (1) containing the electrolytic solution can be manufactured simply and reliably.

[0097] In the manufacturing method of the electrolytic capacitor (1) of the thirteenth aspect, in the eleventh or twelfth aspect, the sealing body (22) is formed by injection molding a sealing resin portion (33) onto the lead portion (31) and the frame portion (32).

[0098] According to the thirteenth aspect, an electrolytic capacitor (1) with improved airtightness can be manufactured simply and reliably.

[0099] In the manufacturing method of the electrolytic capacitor (1) of the fourteenth aspect, in the thirteenth aspect, before the sealing resin portion (33) is injection molded, at least one of a chemical surface treatment and a roughening treatment is applied to the surface of the lead portion (31) that comes into contact with the sealing resin portion (33) and the surface of the frame portion (32) that comes into contact with the sealing resin portion (33).

[0100] According to the fourteenth aspect, an electrolytic capacitor (1) with improved airtightness can be manufactured simply and reliably.

[0101] In a fifteenth aspect of the method for manufacturing an electrolytic capacitor (1), in any one of the eleventh to fourteenth aspects, the anode lead portion (31A) and the anode portion (11A) are joined by laser welding, and the cathode lead portion (31B) and the cathode portion (11B) are joined by laser welding.

[0102] According to the fifteenth aspect, a capacitor element (10) having reduced connection resistance between the anode lead portion (31A) and the cathode lead portion (31B) and the anode portion (11A) and the cathode portion (11B) can be manufactured in a shorter manufacturing takt time.

[0103] In a sixteenth aspect of the method for manufacturing an electrolytic capacitor (1), in any one of the eleventh to fifteenth aspects, the capacitor element (10) includes an anode foil (12A) including an anode portion (11A), a cathode foil (12B) including a cathode portion (11B), and a separator (13) 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 (13) are stacked in a direction from the bottom surface of the housing (21) toward the opening (211).

[0104] According to the sixteenth aspect, an electrolytic capacitor (1) with improved airtightness can be manufactured simply and reliably using a stacked capacitor element (10).

[0105] In a seventeenth aspect of the method for manufacturing an electrolytic capacitor (1), in any one of the eleventh to fifteenth aspects, the capacitor element (10) includes an anode foil (12A) including an anode portion (11A), a cathode foil (12B) including a cathode portion (11B), a separator (13) 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 (13) are wound around a winding axis that intersects with a direction from the bottom surface of the housing (21) toward the opening (211).

[0106] According to the seventeenth aspect, an electrolytic capacitor (1) with improved airtightness can be manufactured simply and reliably using a wound capacitor element (10).

[0107] REFERENCE SIGNS LIST 1 electrolytic capacitor 10 capacitor element 11A anode portion 11B cathode portion 20 case 21 housing 22 sealing body 31 lead portion 31A anode lead portion 31B cathode lead portion 32 frame portion 33 sealing resin portion

Claims

1. An electrolytic capacitor comprising: a capacitor element including an anode portion and a cathode portion; and a case that houses the capacitor element, wherein the case has a housing with an opening and a sealing body that closes the opening of the housing, the sealing body including a lead portion consisting of an anode lead portion and a cathode lead portion, a frame portion that surrounds the lead portions, and a sealing resin portion that fills the gap between the lead portions and the frame, wherein the anode portion of the capacitor element is joined to the anode lead portion, and the cathode portion of the capacitor element is joined to the cathode lead portion.

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 sealing body is an integrated body of the lead portion, the frame portion, and the sealing resin portion.

4. The electrolytic capacitor according to claim 1, wherein the surfaces of the lead portions that come into contact with the sealing resin portion and the surfaces of the frame portions that come into contact with the sealing resin portion are surface-treated surfaces.

5. The electrolytic capacitor according to claim 1, wherein the sealing body is joined to the opening of the housing to seal the opening.

6. The electrolytic capacitor according to claim 1, wherein the sealing resin portion of the sealing body protrudes into the interior of the housing, and the sealing resin portion fits into the opening.

7. The electrolytic capacitor according to claim 1, wherein the lead portion includes an inner lead portion facing the interior of the housing and an outer lead portion located on the opposite side of the inner lead portion, and the first metal constituting the inner lead portion is different from the second metal constituting the outer lead portion.

8. The electrolytic capacitor according to claim 1, wherein the lead portion includes an inner lead portion facing the interior of the housing and an outer lead portion located on the opposite side of the inner lead portion, and the first metal constituting the inner lead portion and the second metal constituting the outer lead portion are the same.

9. The electrolytic capacitor according to claim 1, wherein 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 from the bottom surface of the casing toward the opening.

10. The electrolytic capacitor according to claim 1, wherein the capacitor element comprises an anode foil including the anode portion, a cathode foil including the cathode portion, 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 direction from the bottom surface of the casing toward the opening.

11. A method for manufacturing an electrolytic capacitor, comprising the steps of: preparing a capacitor element including an anode portion and a cathode portion; a housing having an opening; a sealant including a lead portion consisting of an anode lead portion and a cathode lead portion; a frame portion surrounding the lead portion; and a sealing resin portion filling the space between the lead portion and the frame portion; joining the anode lead portion of the sealant to the anode portion of the capacitor element and joining the cathode lead portion of the sealant to the cathode portion of the capacitor element; accommodating the capacitor element within the housing, and positioning the sealant to which the capacitor element is joined so as to close the opening of the housing; and sealing the opening of the housing by welding the sealant to the opening.

12. The method for manufacturing an electrolytic capacitor according to claim 11, further comprising the step of impregnating the capacitor element with an electrolyte solution before the step of sealing the opening.

13. The method for manufacturing an electrolytic capacitor according to claim 11, wherein the sealing body is formed by injection molding the sealing resin portion onto the lead portion and the frame portion.

14. A method for manufacturing an electrolytic capacitor as described in claim 13, wherein, before injection molding the sealing resin portion, the surfaces of the lead portion that come into contact with the sealing resin portion and the surfaces of the frame portion that come into contact with the sealing resin portion are subjected to at least one of a chemical surface treatment and a roughening treatment.

15. The method for manufacturing an electrolytic capacitor according to claim 11, wherein the anode lead portion and the anode portion are joined by laser welding, and the cathode lead portion and the cathode portion are joined by laser welding.

16. The method for manufacturing an electrolytic capacitor according to claim 11, wherein the capacitor element comprises 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 from the bottom surface of the casing toward the opening.

17. The method for manufacturing an electrolytic capacitor according to claim 11, wherein the capacitor element comprises an anode foil including the anode portion, a cathode foil including the cathode portion, 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 direction from the bottom surface of the casing toward the opening.

Images