Electrolytic capacitors

Abstract

This electrolytic capacitor is provided with: a capacitor element; an exterior body which covers the capacitor element; an anode terminal electrically connected to an anode body of the capacitor element; and a cathode terminal electrically connected to a cathode part of the capacitor element. Each of the anode terminal and the cathode terminal is provided with: a connection part in contact with the capacitor element; a lead part that is provided contiguously to the connection part and that is drawn from the inside to an outer surface of the exterior body; and an external terminal part that is provided contiguously to the lead part, that has an exposed surface, and that is disposed on the outer surface of the exterior body. In at least a portion of a covered part, covered by the exterior body, of the lead part of at least one of the anode terminal and the cathode terminal, a cross section formed parallel to a surface region of the outer surface of the exterior body to which the lead part is drawn includes a chamfered corner part.

Description

[Technical field]

[0001] The present invention relates to an electrolytic capacitor including a capacitor element. [Background technology]

[0002] The electrolytic capacitor includes a capacitor element, an exterior body covering the capacitor element, an anode terminal electrically connected to the anode body of the capacitor element, and a cathode terminal electrically connected to the cathode part of the capacitor element. of each teeth a connection portion in contact with the capacitor element; From the connection Exterior body Outside a lead-out portion that is led out to the surface, the lead-out portion being connected to the lead-out portion and being disposed along the outer surface of the exterior body, Exposed from the exterior and an external terminal portion having an exposed surface. In Patent Document 1, a connection portion and an external terminal portion are provided parallel to each other, and a stepped cathode terminal is used with a lead-out portion as a step portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2000-77269 A Summary of the Invention [Problem to be solved by the invention]

[0004] An electrolytic capacitor may be exposed to high temperatures, for example, when soldered to a substrate by a reflow method. When the electrolytic capacitor is exposed to high temperatures, the capacitor element and the exterior body expand. At this time, stress is concentrated at the interface where the exterior body and the corner of the lead-out portion come into contact, and cracks may occur in the exterior body starting from the interface. The cracks reduce the airtightness of the electrolytic capacitor and reduce the reliability of the electrolytic capacitor. [Means for solving the problem]

[0005] One aspect of the present invention Electrolytic capacitors related to teeth ,Ko a capacitor element; and an exterior body covering the capacitor element. , yang Terminal and ,shadow Equipped with pole terminals and The capacitor element includes an anode body, a dielectric layer disposed on a surface of the anode body, and a cathode portion disposed on a surface of the dielectric layer. The anode terminal is electrically connected to the anode body. The cathode terminal is electrically connected to the cathode portion. the anode terminal and the cathode terminal of each teeth a connection portion in contact with the capacitor element; and a connection portion connected to the connection portion, From the connection The exterior body Outside a lead-out portion that is led out to a surface; and a lead-out portion that is connected to the lead-out portion and is disposed along the outer surface. The exposed part is and an external terminal portion having an exposed surface. do. At least a part of a covered portion of the lead-out portion of at least one of the anode terminal and the cathode terminal that is covered with the exterior body. teeth , parallel to the surface area from which the lead-out portion of the outer surface is led out N cross section In , chamfered corners Cross-sectional shape including Yes do. Effect of the Invention

[0006] According to the present invention, the occurrence of cracks in the exterior body of an electrolytic capacitor can be suppressed. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a front view illustrating an example of an electrolytic capacitor according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a vertical sectional view of the electrolytic capacitor of FIG. [Diagram 3] FIG. 2 is a bottom view of the electrolytic capacitor of FIG. 1. [Figure 4] FIG. 4 is an enlarged view of a portion X in FIG. [Diagram 5] 2 is a partially cross-sectional front view of a main portion of the electrolytic capacitor shown in FIG. 1. [Figure 6] FIG. 2 is a perspective view of the cathode terminal in FIG. [Figure 7] FIG. 2 is a front view showing another example of the electrolytic capacitor according to an embodiment of the present invention. [Figure 8] 8 is a cross-sectional view of the cathode terminal in the same plane as the outer surface of the exterior body from which the cathode terminal in FIG. 7 is led out. [Figure 9] FIG. 9 is an enlarged view of a portion Y in FIG. 8. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The electrolytic capacitor according to the embodiment of the present invention includes a capacitor element and an exterior body that covers the capacitor element. do. The capacitor element has an anode body, a dielectric layer disposed on the surface of the anode body, and a cathode portion disposed on the surface of the dielectric layer. The electrolytic capacitor also includes an anode terminal electrically connected to the anode body, and a cathode terminal electrically connected to the cathode portion. The anode terminal and the cathode terminal (hereinafter also referred to as electrode terminals) of each teeth a connection portion in contact with the capacitor element; From the connection Exterior body Outside a lead-out portion that is led out to the surface, the lead-out portion being connected to the lead-out portion and being disposed along the outer surface of the exterior body, Exposed from the exterior and an external terminal portion having an exposed surface. At least a part of a covered portion (hereinafter also referred to as covered portion A) of the lead-out portion of at least one of the anode terminal and the cathode terminal that is covered with an exterior body. teeth , the lead-out portion of the outer surface of the exterior body is parallel to the surface area from which it is led out N Cross section (hereinafter also referred to as cross section B) In , chamfered corners Cross-sectional shape including Yes.

[0009] By chamfering the corners of the lead-out portion, when the electrolytic capacitor is exposed to high temperatures and the capacitor element expands, the concentration of stress at the interface where the exterior body and the corners of the lead-out portion come into contact is mitigated, and the occurrence of cracks in the exterior body originating from the interface is suppressed, thereby ensuring the airtightness of the electrolytic capacitor and improving the reliability of the electrolytic capacitor.

[0010] The above-mentioned cracks are likely to occur when there is a region where the distance from the surface of the capacitor element to the outer surface of the exterior body is short, i.e., when there is a thin-walled region where the thickness of the exterior body is small and the lead-out portion is arranged in the thin-walled region. Therefore, when the lead-out portion is arranged in the thin-walled region and the cross section B of the lead-out portion has a chamfered corner, the effect of suppressing the occurrence of cracks in the exterior body becomes significant.

[0011] It is preferable that the cross section B has a chamfered corner at least at the boundary portion where the lead-out portion begins to be exposed from the outer surface of the exterior body. Cracks are likely to occur in the exterior body starting from the point where the exterior body contacts the boundary portion of the lead-out portion. Therefore, when the cross section B has a chamfered corner at the boundary portion, the effect of suppressing cracks in the exterior body becomes significant.

[0012] The boundary portion of the lead-out portion that begins to be exposed from the outer surface of the exterior body may form a bent portion, and the lead-out portion may be connected to the external terminal portion at the bent portion. In this case, it is preferable that at least the cross section B corresponding to the bent portion has a chamfered corner on the inside of the bending direction of the bent portion (the concave side of the bent portion). The exterior body is prone to cracks starting from the point where it contacts the inside of the bending direction of the bent portion. Therefore, when the cross section B has a chamfered corner on the inside of the bending direction of the bent portion, the effect of suppressing cracks in the exterior body becomes significant.

[0013] The cross section B of the lead-out portion may have multiple (e.g., two or four) corners. From the viewpoint of enhancing the effect of suppressing crack generation, it is preferable that all corners in the cross section B of at least a part of the covered portion A of the lead-out portion are chamfered corners. It is also preferable that all corners in the cross section B of the entire covered portion A are chamfered corners.

[0014] The chamfered shape of the corner of the lead-out portion is not particularly limited, and may be, for example, an R-chamfered shape or a C-chamfered shape. The R-chamfered shape is obtained by R-chamfering, which cuts off the sharp corner at an angle of 45°. The R-chamfered shape is performed, for example, in the range of R0.01 or more and R0.05 or less. For example, in the case of R0.05, the R-chamfered shape is performed so that the corner becomes curved with a radius of curvature of 0.05 mm. The C-chamfered shape is performed, for example, in the range of C0.01 or more and C0.05 or less. For example, in the case of C0.05, the sharp corner is formed into an isosceles right triangle with two sides of 0.05 mm. To remove the part with a cross section of The chamfering of the corners of the lead-out portion may be performed simultaneously with the formation of the electrode terminal, or may be performed after the formation of the electrode terminal.

[0015] The exposed surfaces of the external terminals of the electrode terminals are used for soldering to a substrate on which the electrolytic capacitor is to be mounted. The electrode terminals may be made of a lead frame, which may be made of, for example, copper or a copper alloy.

[0016] The electrode terminal can be manufactured, for example, by preparing a specific mold capable of forming an electrode terminal including a lead-out portion having chamfered corners, and using the mold to punch out a metal sheet.

[0017] The electrode terminal may be produced by the following method. A metal sheet is punched to form an intermediate body (an electrode terminal before the corners of the lead-out portion are chamfered). Then, a specific die is separately prepared for chamfering the corners of a specific portion of the intermediate body (at least the portion corresponding to the lead-out portion). The corners of the specific portion of the intermediate body are chamfered by punching using the die.

[0018] The exterior body and the capacitor element will be described in detail below. (Exterior body) The exterior body includes a resin material, and preferably includes a cured product of a curable resin composition, and may include a thermoplastic resin or a composition including the same. The exterior body can be formed using a molding technique such as injection molding, insert molding, or compression molding. The exterior body can be formed, for example, by using a predetermined mold to fill a curable resin composition or a thermoplastic resin (composition) into a predetermined location so as to cover the outer surface of the capacitor element as well as a part of the electrode terminal.

[0019] The curable resin composition may contain, in addition to the curable resin, a filler, a curing agent, a polymerization initiator, a catalyst, and the like. As the curable resin, for example, a compound (for example, a monomer, an oligomer, a prepolymer, and the like) that is cured or polymerized by the action of heat is used. Examples of such compounds (or curable resins) include epoxy resins, phenolic resins, urea resins, polyimides, polyamideimides, polyurethanes, diallyl phthalates, unsaturated polyesters, and the like. The curable resin composition may contain a plurality of curable resins.

[0020] As the filler, for example, insulating particles (inorganic, organic) and / or fibers are preferable. As the insulating material constituting the filler, for example, insulating compounds (oxides, etc.) such as silica and alumina, glass, mineral materials (talc, mica, clay, etc.) and the like can be mentioned. As the filler, one type may be used alone, or two or more types may be used in combination. The curing agent, polymerization initiator, catalyst, etc. are appropriately selected according to the type of the curable resin.

[0021] Examples of the thermoplastic resin that can be used include polyphenylene sulfide (PPS), polybutylene terephthalate (PBT), etc. The composition containing the thermoplastic resin may contain the above-mentioned filler, etc., in addition to the thermoplastic resin.

[0022] (Capacitor element) The capacitor element includes an anode body, a dielectric layer covering the anode body, and a cathode portion covering the dielectric layer.

[0023] (Anode body) The anode body may include an anode wire and a porous body made of a valve metal. The anode wire has a first portion embedded in the porous body and a second portion extending out from the porous body so as to stand, and the connection portion of the anode terminal is connected to the second portion.

[0024] The porous body is, for example, a sintered body of a valve metal. One end of the anode wire is embedded in the sintered body. The anode body is obtained, for example, by pressing a powder containing a valve metal with one end of the anode wire embedded in the powder to obtain a molded body of a desired shape (for example, a block shape), and then sintering the molded body. Examples of the valve metal contained in the porous body include tantalum.

[0025] The anode body may be a foil or plate-shaped substrate containing a valve metal. The surface of the substrate is roughened by etching or the like. The substrate may be made of a valve metal, an alloy containing a valve metal, or a compound containing a valve metal. These may be used alone or in combination of two or more. Examples of the valve metal contained in the substrate include aluminum, tantalum, niobium, and titanium.

[0026] When the above-mentioned base material is used for the anode body, the anode body has a region facing the cathode part and a region not facing the cathode part. It is sufficient that the surface of the base material is roughened at least in the region facing the cathode part. In the region of the anode body not facing the cathode part, an insulating separation layer is formed in a band-like shape on the surface of the anode body in a portion adjacent to the cathode part, thereby restricting contact between the cathode part and the anode body. In the region of the anode body not facing the cathode part, another part is electrically connected to the anode terminal by welding.

[0027] (Dielectric layer) The dielectric layer includes an oxide of a valve metal (e.g., aluminum oxide, tantalum pentoxide, etc.). The dielectric layer is formed along the porous surface of the anode body (including the inner wall surfaces of the pores). The surface of the dielectric layer has an uneven shape corresponding to the shape of the surface of the anode body.

[0028] The dielectric layer is formed, for example, by anodizing the surface of the anode body. The anodization can be performed by a known method, for example, chemical conversion treatment. The chemical conversion treatment can be performed, for example, by immersing the anode body in a chemical conversion solution to impregnate the surface of the anode body with the chemical conversion solution, and applying a voltage between the anode body as an anode and a cathode immersed in the chemical conversion solution. For example, an aqueous phosphoric acid solution can be used as the chemical conversion solution.

[0029] (cathode) The cathode portion includes a solid electrolyte layer covering at least a portion of the dielectric layer, and a cathode lead layer covering the solid electrolyte layer. The cathode lead layer includes, for example, a carbon layer covering the solid electrolyte layer, and a silver paste layer covering the carbon layer. The silver paste layer of the cathode portion is electrically connected to the connection portion of the cathode terminal via an adhesive layer formed of a conductive adhesive.

[0030] The solid electrolyte layer includes, for example, a manganese compound and a conductive polymer. Examples of the conductive polymer that can be used include polypyrrole, polythiophene, polyaniline, and derivatives thereof. The solid electrolyte layer may include a dopant. More specifically, the solid electrolyte layer may include poly(3,4-ethylenedioxythiophene) (PEDOT) as the conductive polymer and polystyrene sulfonate (PSS) as the dopant.

[0031] The solid electrolyte layer is formed, for example, by chemical polymerization and / or electrolytic polymerization of raw material monomers on the dielectric layer. Alternatively, the solid electrolyte layer may be formed by applying a treatment liquid containing a conductive polymer to the dielectric layer and then drying it. The treatment liquid may further contain other components such as a dopant. The treatment liquid is a dispersion or solution of the conductive polymer. Examples of the dispersion medium (solvent) include water, organic dispersion medium ( organic solvent), or a mixture thereof.

[0032] The carbon layer may be formed of any conductive carbon material such as graphite, etc. The silver paste layer may be formed of a composition containing silver powder and a binder resin (such as an epoxy resin).

[0033] Hereinafter, an example of an electrolytic capacitor according to an embodiment of the present invention will be described with reference to FIGS. 1 to 6. FIG. 1 is a front view showing an example of an electrolytic capacitor according to an embodiment of the present invention. FIG. 2 is a vertical cross-sectional view of the electrolytic capacitor of FIG. 1. FIG. 2 shows a cross section perpendicular to the side surface 6a of the exterior body 6 and along the longitudinal direction of the anode wire 9. FIG. 3 is a bottom view of the electrolytic capacitor of FIG. 1, in which the electrolytic capacitor is viewed from the side surface 6a. FIG. 4 is an enlarged view of the X portion of FIG. 3. FIG. 5 is a front view of a main part of the electrolytic capacitor of FIG. 1, in which a part of the electrolytic capacitor is cross-sectionally shown. In FIG. 5, only the exterior body 6 is cross-sectionally shown for convenience. P1 in FIG. 5 indicates a boundary portion where the lead-out portion 15 starts to be exposed from the side surface 6a of the exterior body 6. P2 in FIG. 5 indicates the inside of the bending direction of the bent portion 20 (the concave side of the bent portion 20). FIG. 6 is a perspective view of the cathode terminal in FIG. 1.

[0034] The electrolytic capacitor 1 includes a capacitor element 2. The capacitor element 2 includes an anode body 3, a dielectric layer 4 disposed on the surface of the anode body 3, and a cathode portion 5 disposed on the surface of the dielectric layer 4. The electrolytic capacitor 1 includes the capacitor element 2, an exterior body 6 covering the capacitor element 2, an anode terminal 7 electrically connected to the anode body 3, and a cathode terminal 8 electrically connected to the cathode portion 5. The exterior body 6 has an outer shape of a substantially rectangular parallelepiped, and the electrolytic capacitor 1 also has an outer shape of a substantially rectangular parallelepiped. The side surface 6a of the exterior body 6 is one of six side surfaces of the rectangular parallelepiped that is the outer shape of the exterior body 6.

[0035] The anode body 3 includes an anode wire 9 and a porous body 10 made of a valve metal. The anode wire 9 has a first portion 9a embedded in the porous body 10 and a second portion 9b extending out from the porous body 10 so as to stand upright. The porous body 10 is, for example, a porous sintered body of tantalum. The dielectric layer 4 is, for example, a layer of tantalum pentoxide.

[0036] Cathode unit 5 includes a solid electrolyte layer covering at least a portion of dielectric layer 4, and a cathode extraction layer covering the solid electrolyte layer. The cathode extraction layer includes a carbon layer covering the solid electrolyte layer, and a silver paste layer covering the carbon layer.

[0037] The anode terminal 7 includes a connection portion 11 in contact with the capacitor element 2, a lead-out portion 12 connected to the connection portion 11, and an external terminal portion 13 connected to the lead-out portion 12. The lead-out portion 12 is connected to the exterior body 6. Inside of Connection 11 from Outer body 6 The external terminal 13 is exposed to the side surface 6a of the exterior body 6. The external terminal 13 is disposed along the side surface 6a of the exterior body 6 and has an exposed surface 13a. The connection portion 11 of the anode terminal 7 is connected to the second portion 9b of the anode wire 9 by welding. A portion of the external terminal 13 on the exterior body 6 side is embedded in the exterior body 6.

[0038] The cathode terminal 8 includes a connection portion 14 in contact with the capacitor element 2, a lead-out portion 15 connected to the connection portion 14, and an external terminal portion 16 connected to the lead-out portion 15. The lead-out portion 15 is connected to the exterior body 6. Inside of Connection 14 from Outer body 6 The external terminal portion 16 is disposed along the side surface 6a of the exterior body 6 and has an exposed surface 16a. The connection portion 14 of the cathode terminal 8 is electrically connected to the silver paste layer of the cathode portion 5 via an adhesive layer (not shown) formed of a conductive adhesive.

[0039] In the cathode terminal 8, the connection portion 14 and the external terminal portion 16 are provided parallel to each other. Here, "parallel" means that the angle (acute angle) formed by the connection portion 14 and the external terminal portion 16 is 0° or more and 10° or less. As shown in FIG. 2 and FIG. 6, the cathode terminal 8 is formed in a stepped shape by the connection portion 14, the lead-out portion 15, and the external terminal portion 16. The connection portion 14 and the external terminal portion 16 are located on the side of the side surface 6a of the exterior body 6 as viewed from the capacitor element 2. The lead-out portion 15 has a bent portion 19 at the boundary with the connection portion 14, and a bent portion 20 at the boundary with the external terminal portion 16. A part of the bent portion 20 is exposed to the outside from the side surface 6a of the exterior body 6.

[0040] A cross section B of lead-out portion 15 of exterior body 6, which is formed parallel to side surface 6a from which lead-out portion 15 is led out, has chamfered corner 17. Corner 17 is chamfered to have a R-chamfered shape. The radius of curvature of R-chamfered corner 17 in cross section B is, for example, 0.01 mm or more and 0.05 mm or less.

[0041] In the entire covered portion A of the lead-out portion 15 that is covered by the exterior body 6, all of the corners in the cross section B of the lead-out portion 15 are chamfered corners 17. For example, the cross section B at the boundary portion P1 where the lead-out portion 15 begins to be exposed from the side surface 6a of the exterior body 6 has two chamfered corners 17. The cross section B corresponding to the bent portion 20 has two chamfered corners 17 on each of the inner side P2 and the outer side in the bending direction of the bent portion 20.

[0042] The stepped lead-out portion 15 of the cathode terminal 8 is disposed in a thin region where the thickness of the exterior body 6 is small (a region where the distance from the side surface 6a of the exterior body 6 to the capacitor element 2 is short). In the exterior body, cracks are likely to occur starting from the interface where the thin region and a corner of the lead-out portion of the cathode terminal come into contact. Therefore, by providing chamfered corner 17 at cross section B in lead-out portion 15 of the cathode terminal 8 disposed in the thin region, a significant effect of suppressing cracks in the exterior body can be obtained.

[0043] At least at boundary P1 where lead-out portion 15 begins to be exposed from side surface 6a of exterior body 6, cross section B preferably has chamfered corner 17. Cracks tend to occur in the exterior body starting from the point where it contacts boundary P1 of the lead-out portion. Therefore, by cross section B having chamfered corner 17 at boundary P1, the effect of suppressing cracks in the exterior body can be significantly obtained.

[0044] As shown in FIG. 1 and FIG. 2, a part of the external terminal 16 on the exterior body 6 side is embedded in the exterior body 6. In this case, as shown in FIG. 5, the boundary P1 where the lead-out portion 15 starts to be exposed from the side surface 6a of the exterior body 6 forms the bent portion 20. That is, the bent portion 20 includes the boundary P1. The lead-out portion 15 is connected to the external terminal 16 at the bent portion 20. In this case, it is preferable that at least the cross section B corresponding to the bent portion 20 has a chamfered corner 17 on the inner side P2 in the bending direction of the bent portion 20 (the concave side of the bent portion 20). The exterior body is prone to cracks starting from the point where the cross section B contacts the inner side P2 in the bending direction of the bent portion. Therefore, by having the chamfered corner 17 on the inner side P2 in the bending direction of the bent portion 20, the effect of suppressing the occurrence of cracks in the exterior body can be significantly obtained.

[0045] In this embodiment, external terminal portion 16 of cathode terminal 8 has a chamfered corner 18 that is continuous with chamfered corner 17 of lead-out portion 15. The corner of the external terminal portion does not have to be chamfered.

[0046] In this embodiment, in the entire covered portion A of the lead-out portion 15 covered with the exterior body 6, all of the corners in the cross section B of the lead-out portion 15 are chamfered corners 17, but it is sufficient that the cross section B of the lead-out portion has a chamfered corner in at least a part of the covered portion A. Corners 17 and 18 are R-chamfered, but the chamfered shape of the corners may be C-chamfered. The corners of the lead-out portion 12 of the anode terminal 7 are not chamfered, but the lead-out portion of the anode terminal may have a chamfered corner.

[0047] Another example of an electrolytic capacitor according to an embodiment of the present invention will be described below with reference to Figs. 7 to 9. Fig. 7 is a front view showing another example of an electrolytic capacitor according to an embodiment of the present invention. Fig. 8 is a cross-sectional view of the cathode terminal in Fig. 7 on the same plane as side surface 26b of the exterior body from which the cathode terminal is led out, and shows cross section B at boundary portion P3 where lead-out portion 35 begins to be exposed from side surface 26b of exterior body 26. Fig. 9 is an enlarged view of portion Y in Fig. 8.

[0048] The electrolytic capacitor 21 includes a capacitor element 22. The capacitor element 22 has the same configuration as the capacitor element 2 in FIG. 1 and FIG. 2. The electrolytic capacitor 21 includes the capacitor element 22, an exterior body 26 that covers the capacitor element 22, an anode terminal 27 that is electrically connected to the anode body of the capacitor element 22, and a cathode terminal 28 that is electrically connected to the cathode part of the capacitor element 22. The exterior body 26 has an outer shape of a substantially rectangular parallelepiped, and the electrolytic capacitor 21 also has an outer shape of a substantially rectangular parallelepiped. The side surfaces 26a to 26c of the exterior body 26 are three of six side surfaces of the rectangular parallelepiped that is the outer shape of the exterior body 26. The side surface 26a and the side surface 26b are located on opposite sides to each other, and are perpendicular to the side surface 26c.

[0049] The anode terminal 27 includes a connection portion 31 in contact with the capacitor element 22, a lead-out portion 32 connected to the connection portion 31, and an external terminal portion 33 connected to the lead-out portion 32. The lead-out portion 32 is connected to the exterior body 26. Inside of Connection 31 from Outer body 26 The external terminal 33 is led out to the side surface 26a. The external terminal 33 is arranged along the side surface 26a to the side surface 26c of the exterior body 26. The portion of the external terminal 33 arranged along the side surface 26c of the exterior body 26 has an exposed surface 33a. The portion of the external terminal 33 having the exposed surface 33a is arranged in a recessed portion provided in the side surface 26c of the exterior body 26. The connection portion 31 of the anode terminal 27 is connected to the second portion 29b of the anode wire of the capacitor element 22 by welding.

[0050] The cathode terminal 28 includes a connection portion 34 in contact with the capacitor element 22, a lead-out portion 35 connected to the connection portion 34, and an external terminal portion 36 connected to the lead-out portion 35. The lead-out portion 35 is connected to the exterior body 26. Inside of Connection 34 from Outer body 26It is led out to the side surface 26b. The external terminal portion 36 is arranged along the side surface 26b to the side surface 26c of the exterior body 26. The portion of the external terminal portion 36 arranged along the side surface 26c of the exterior body 26 has an exposed surface 36a. The portion of the external terminal portion 36 having the exposed surface 36a is arranged in a recess provided in the side surface 26c of the exterior body 26. The connection portion 34 of the cathode terminal 28 is electrically connected to the silver paste layer of the cathode portion of the capacitor element 22.

[0051] As shown in FIG. 7, the cathode terminal 28 is formed in a substantially U-shape by the connection portion 34, the lead-out portion 35, and the external terminal portion 36. The capacitor element 22 is positioned between the contact portion of the connection portion 34 with the capacitor element 22 and the portion of the external terminal portion 36 having the exposed surface 36a. The lead-out portion 35 has a bent portion 39 at the boundary portion with the connection portion 34 and a bent portion 40 at the boundary portion with the external terminal portion 36. The bent portion 40 is exposed to the outside from the side surface 26b of the exterior body 26.

[0052] As shown in FIG. 9, the cross-section B of the lead-out portion 35 formed parallel to the side surface 26b from which the lead-out portion 35 of the exterior body 26 is led out has a chamfered corner portion 37. The chamfered shape of the corner portion 37 is an R-chamfered shape. In the entire covered portion A of the lead-out portion 35 covered by the exterior body 26, all of the corners in the cross-section B of the lead-out portion 35 are the chamfered corner portions 37. For example, the cross-section B at the boundary portion P3 where the lead-out portion 3 5 begins to be exposed from the side surface 26b of the exterior body 26 has four chamfered corner portions 37.

[0053] The portion of the lead-out portion 35 exposed to the outside from the side surface 26b of the exterior body 26 forms the bent portion 40. That is, the bent portion 40 does not include the boundary portion P3 where the lead-out portion 3 5 begins to be exposed from the side surface 26b of the exterior body 26. The lead-out portion 35 is connected to the external terminal portion 36 at the bent portion 40. In this case, at least at the boundary portion P3 where the lead-out portion 3 5 begins to be exposed from the side surface 26b of the exterior body 26, it is preferable that the cross-section B has a chamfered corner portion 37.

[0054] In this embodiment, in the entire covered portion A of the lead-out portion 35 covered with the exterior body 26, all of the corners in the cross section B of the lead-out portion 35 are chamfered corners 37, but it is sufficient that the cross section B of the lead-out portion has a chamfered corner in at least a part of the covered portion A. The corners 37 are R-chamfered, but the corners may also be C-chamfered. The corners of the lead-out portion 32 of the anode terminal 27 are not chamfered, but the lead-out portion of the anode terminal may have a chamfered corner. [Industrial Applicability]

[0055] The electrolytic capacitor according to the present invention can be used in a variety of applications requiring high reliability even when exposed to a high-temperature atmosphere. [Explanation of symbols]

[0056] 1, 21: electrolytic capacitor, 2, 22: capacitor element, 3: anode body, 4: dielectric layer, 5: cathode portion, 6, 26: exterior body, 6a, 26a, 26b, 26c: side surface of exterior body, 7, 27: anode terminal, 8, 28: cathode terminal, 9: anode wire, 9a: first portion, 9b, 29b: second portion, 10: porous body, 11, 31: connection portion of anode terminal, 12, 32: lead-out portion of anode terminal, 13, 33: external terminal portion of anode terminal; 13a, 33a: exposed surfaces of external terminal portion of anode terminal; 14, 34: connection portion of cathode terminal; 15, 35: lead-out portion of cathode terminal; 16, 36: external terminal portion of cathode terminal; 16a, 36a: exposed surfaces of external terminal portion of cathode terminal; 17, 37: corner portion of lead-out portion of cathode terminal; 18: corner portion of external terminal portion of cathode terminal; 19, 20, 39, 40: bent portion of lead-out portion of cathode terminal

Claims

1. a capacitor element including an anode body, a dielectric layer disposed on a surface of the anode body, and a cathode portion disposed on a surface of the dielectric layer; an exterior body covering the capacitor element; an anode terminal electrically connected to the anode body; a cathode terminal electrically connected to the cathode portion, each of the anode terminal and the cathode terminal includes a connection portion in contact with the capacitor element; a lead-out portion connected to the connection portion and led from the connection portion to an outer surface of the exterior body; and an external terminal portion connected to the lead-out portion, arranged along the outer surface, and having an exposed surface exposed from the exterior body; a boundary portion which is at least a part of a covered portion of the lead-out portion of the cathode terminal that is covered with the exterior body and starts to be exposed from the outer surface has a cross-sectional shape which includes a chamfered corner portion in a cross section parallel to a surface region of the outer surface from which the lead-out portion is led out, an external terminal portion having a chamfered corner; and a connection portion having a non-chamfered corner.

2. The boundary portion has a bent portion, The bent portion is connected to the external terminal portion, 2 . The electrolytic capacitor according to claim 1 , wherein the bent portion has a cross-sectional shape including a chamfered corner on an inner side of the cross-section in a bending direction of the bent portion.

3. the connection portion of the cathode terminal and the external terminal portion of the cathode terminal are provided in parallel to each other, 3. The electrolytic capacitor according to claim 1, wherein the cathode terminal is formed in a stepped shape by the connection portion, the lead-out portion, and the external terminal portion of the cathode terminal.

4. The anode body includes an anode wire and a porous body of a valve metal, the anode wire has a first portion embedded in the porous body and a second portion extending out from the porous body in an upright manner; 4. The electrolytic capacitor according to claim 1, wherein the connection portion of the anode terminal is connected to the second portion.

5. 5. The electrolytic capacitor according to claim 1, wherein all corners in the cross-sectional shape are chamfered corners.

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