Electrolytic capacitors

Abstract

The present invention provides an electrolytic capacitor, comprising a capacitor element, a cathode lead terminal and an outer casing. The cathode lead terminal comprises: a first cathode lead portion, which is opposite to the first main surface of the capacitor element; a second cathode lead portion, which is bent from the first cathode lead portion and extends in a direction along a surface intersecting the first main surface; a third cathode lead portion, which is bent and extended from the second cathode lead portion and exposed from the outer casing; and a fourth cathode lead portion, which is bent from the first cathode lead portion and extends along the second main surface of the capacitor element. The height h of the fourth cathode lead portion in the normal direction of the first main surface is less than the height H in the normal direction of the first main surface from the first cathode lead portion to the portion of the third cathode lead portion that is not exposed from the outer casing.

Description

Technical Field

[0001] The present invention relates to electrolytic capacitors. Background Art

[0002] Electrolytic capacitors are used in a variety of electronic devices because of their low equivalent series resistance (ESR) and excellent frequency characteristics. Typically, an electrolytic capacitor includes: a capacitor element having an anode portion and a cathode portion; an anode lead terminal electrically connected to the anode portion; and a cathode lead terminal electrically connected to the cathode portion. Typically, the capacitor element is sealed by an outer casing.

[0003] As a structure of a cathode lead terminal, Patent Document 1 discloses a structure in which an embedding portion for positioning a capacitor element in the cathode lead terminal is provided.

[0004] Prior Art Literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2003-68576 Summary of the invention

[0007] Problem that the invention aims to solve

[0008] In Patent Document 1, since the capacitor element can be positioned parallel to the cathode lead terminal, positioning deviation can be reduced. As a result, the electrical connectivity of the electrolytic capacitor is improved, and reliability can be improved. However, the current situation is that further improvement in reliability is desired.

[0009] Technical solutions to solve problems

[0010] An electrolytic capacitor according to one aspect of the present invention comprises: a capacitor element having an anode portion and a cathode portion; a cathode lead terminal electrically connected to the cathode portion; and an outer casing covering the capacitor element with a portion of the cathode lead terminal exposed. The capacitor element has a first main surface, a second main surface sharing a side with the first main surface, and a third main surface sharing a side with the first main surface and located on the opposite side of the second main surface. The cathode lead terminal includes: a first cathode lead portion facing the first main surface of the capacitor element; a second cathode lead portion bent from the first cathode lead portion at a first bent portion and extending in a direction along a plane intersecting the first main surface, the second main surface, and the third main surface; a third cathode lead portion bent from the second cathode lead portion and extending in a direction along the first main surface, then exposed from the outer casing, further bent and extending along the outer surface of the outer casing; and a fourth cathode lead portion bent from the first cathode lead portion at a position different from the first bent portion and extending along the second main surface. The height h of the fourth cathode lead portion in the normal direction of the first main surface is less than the height H in the normal direction of the first main surface from the first cathode lead portion to the portion of the third cathode lead portion not exposed from the outer casing.

[0011] Another aspect of the present invention relates to an electrolytic capacitor comprising: a capacitor element having an anode portion and a cathode portion; a cathode lead terminal electrically connected to the cathode portion; and an outer casing covering the capacitor element in a state where a portion of the cathode lead terminal is exposed. The anode portion comprises an anode body arranged inside the cathode portion, and an anode wire extending from the anode body to the outside of the cathode portion. The capacitor element comprises a first main surface, a second main surface sharing a side with the first main surface, and a third main surface sharing a side with the first main surface and located on the opposite side of the second main surface. The cathode lead terminal comprises: a first cathode lead portion facing the first main surface of the capacitor element; and a fourth cathode lead portion bent from the first cathode lead portion and extending along the second main surface. The height h of the fourth cathode lead portion in the normal direction of the first main surface is smaller than the height H2 in the normal direction of the first main surface from the first cathode lead portion to the anode wire.

[0012] Effects of the Invention

[0013] According to the present invention, the reliability of the electrolytic capacitor is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1A It is a cross-sectional view schematically showing the structure of an electrolytic capacitor according to one embodiment of the present invention.

[0015] Figure 1B yes Figure 1A A cross-sectional view of an electrolytic capacitor taken along line X1-X2.

[0016] Figure 2 It is a schematic cross-sectional view of a capacitor element according to one embodiment of the present invention. DETAILED DESCRIPTION

[0017] The electrolytic capacitor involved in this embodiment comprises: a capacitor element, comprising an anode portion and a cathode portion; an anode lead terminal, electrically connected to the anode portion; a cathode lead terminal, electrically connected to the cathode portion; and an outer casing. The outer casing covers the capacitor element in a state where a portion of the anode lead terminal and the cathode lead terminal are exposed. The capacitor element has a first main surface, a second main surface that shares a side with the first main surface, and a third main surface that shares a side with the first main surface and is located on the opposite side of the second main surface. The anode portion is electrically connected to the anode lead terminal, and can be electrically connected to the anode electrode or external terminal of the electrolytic capacitor via the anode lead terminal. The anode portion can also be electrically connected directly to the anode electrode without passing through the anode lead terminal.

[0018] The cathode lead terminal includes, for example, a first cathode lead portion facing the first main surface of the capacitor element; a second cathode lead portion bent from the first cathode lead portion and extending in a direction along a surface intersecting the first main surface, the second main surface, and the third main surface; and a third cathode lead portion bent from the second cathode lead portion and extending in a direction along the first main surface, then exposed from the outer casing, further bent, and extending along the outer surface of the outer casing. Here, the boundary between the first cathode lead portion and the second cathode lead portion is set as the first bent portion. The boundary between the second cathode lead portion and the third cathode lead portion is set as the second bent portion.

[0019] The cathode portion is formed, for example, as an anode portion (anode body) having a substantially rectangular parallelepiped shape covered by a dielectric layer. In this case, similarly to the anode portion, the cathode portion can also be formed as an outer surface having a substantially rectangular parallelepiped. The first to third principal surfaces of the capacitor element can be the outer surfaces of the cathode portion of the substantially rectangular parallelepiped. In this case, the outer surface of the cathode portion can have a fourth principal surface orthogonal to the first to third principal surfaces, and a fifth principal surface on the opposite side of the first principal surface. These principal surfaces do not necessarily need to be planes, and may also have a curved surface shape, or have some concave-convex shapes, and / or may also be formed by a plane that is bent multiple times. In addition, the angles formed by adjacent principal surfaces can be right angles, acute angles, or obtuse angles, respectively. In other words, a principal surface may be inclined relative to other principal surfaces.

[0020] In addition, the electrolytic capacitor may be an electrolytic capacitor formed by stacking a plurality of capacitor elements using roughened foil as the anode portion. In this case, in the stacking direction of the stack of capacitor elements, the outer surface of the cathode portion of the capacitor element at one end of the stack of capacitor elements may be the first principal surface, and the outer surface of the cathode portion of the capacitor element at the other end may be the fifth principal surface. The second to fourth principal surfaces may be outer surfaces parallel to the stacking direction of the stack of capacitor elements.

[0021] On the first main surface side, the cathode portion and the first cathode lead portion of the cathode lead terminal are electrically connected. The cathode lead terminal can be bent parallel to the fourth main surface of the cathode portion, and after forming the second cathode lead portion, it can be further bent and extended in the direction along the first main surface (for example, in a direction parallel to the first main surface) to form a third cathode lead portion. As a result, the first to third cathode lead portions are bent to form a crank, and a portion of the third cathode lead portion is exposed from the outer casing. Electrical connection is made to the external terminal in the portion of the third cathode lead portion that is exposed from the outer casing.

[0022] Typically, the outer casing has a shape corresponding to or similar to that of the capacitor element, and the outer surface of the outer casing has a principal surface corresponding to the first to fifth principal surfaces of the cathode portion. The exposed portion of the third cathode lead portion exposed from the outer casing may be bent in a direction away from the first principal surface and extended in a direction along the fourth principal surface, and then further bent to extend along the principal surface of the outer casing corresponding to the fifth principal surface on the opposite side of the first principal surface.

[0023] The cathode lead terminal further includes a fourth cathode lead portion that is bent from the first cathode lead portion at a position different from the first bent portion and extends along the second main surface. The cathode lead terminal may also include a fifth cathode lead portion that is bent from the first cathode lead portion at a position different from the first bent portion and extends along the third main surface. That is, when the first main surface is set as the bottom surface of the cathode portion, the fourth cathode lead portion and the fifth cathode lead portion are bent and extended from the first cathode lead portion in a manner covering the side surface of the cathode portion. The fourth cathode lead portion and / or the fifth cathode lead portion function as a guide for placing and fixing the capacitor element on the cathode lead terminal in a manner that the first main surface overlaps with the first cathode lead portion, making it easy to position the capacitor element. In particular, when the height of the fourth cathode lead portion and / or the fifth cathode lead portion is lower than the height from the first cathode lead portion to the second bent portion, the capacitor element can be mounted on the first cathode lead portion without touching the second bent portion. This makes it possible to reliably position the capacitor element at a desired position of the cathode lead terminal, thereby improving reliability.

[0024] In addition, usually, the electrolytic capacitor electrically connects the cathode portion and the first cathode lead portion via a conductive adhesive material provided on the first main surface. In this case, the conductive adhesive material may be interposed between the second main surface and the fourth cathode lead portion and / or between the third main surface and the fifth cathode lead portion in addition to between the first main surface and the first cathode lead portion. As a result, the electrical connection between the capacitor element and the cathode lead terminal becomes stable, and reliability is improved. In addition, ESR can be reduced.

[0025] Preferably, the fourth cathode lead portion extends along the second main surface in a state separated from the second main surface. Similarly, the fifth cathode lead portion extends along the third main surface in a state separated from the third main surface. In this case, although it also depends on the amount of the conductive adhesive material, when the capacitor element is bonded and fixed to the first cathode lead portion, the conductive adhesive material between the first main surface and the first cathode lead portion can also enter the gap between the second main surface and the fourth cathode lead portion and / or between the third main surface and the fifth cathode lead portion. As a result, the contact area with the conductive adhesive material can be increased, the reliability is improved, and the ESR can be reduced.

[0026] In this case, the conductive adhesive material may not exist in the region that is higher than the height of the fourth cathode lead portion and / or the fifth cathode lead portion relative to the first main surface. That is, the conductive adhesive material only needs to be located in a portion of the gap between the second main surface and the fourth cathode lead portion so as not to overflow from the gap between the second main surface and the fourth cathode lead portion. Similarly, the conductive adhesive material only needs to be located in a portion of the gap between the third main surface and the fifth cathode lead portion so as not to overflow from the gap between the third main surface and the fifth cathode lead portion. In addition, the above description does not exclude the presence of other conductive adhesive materials that are not caused by the conductive adhesive material between the fourth cathode lead portion and the second main surface and / or between the fifth cathode lead portion and the third main surface in the region that is higher than the height of the fourth cathode lead portion and / or the fifth cathode lead portion relative to the first main surface.

[0027] The constituent material of the outer casing may be interposed in the gap (where no conductive adhesive material is present) between the second main surface and the fourth cathode lead portion and / or between the third main surface and the fifth cathode lead portion. The portion of the gap not filled with the conductive adhesive material may be filled with the constituent material of the outer casing so that no void is generated. Thus, the adhesion between the outer casing and the capacitor element can be improved through the anchoring effect, and the reliability is improved.

[0028] Regarding the height of the fourth cathode lead portion, it is sufficient that the height h in the normal direction of the first main surface when the first cathode lead portion is used as a reference is higher than the thickness of the conductive adhesive material between the first cathode lead portion and the first main surface so that the conductive adhesive material does not overflow. The height h may be more than 2 times or more than 3 times the height of the conductive adhesive material between the first cathode lead portion and the first main surface. On the other hand, if the height h of the fourth cathode lead portion is too high, warping and bending are likely to occur in the fourth cathode lead portion, and sometimes it becomes difficult to bond and fix the capacitor element to the first cathode lead portion. In particular, when the height h exceeds the height H in the normal direction of the first main surface from the first cathode lead portion to the portion of the third cathode lead portion that is not exposed from the outer body (in other words, the distance from the first cathode lead portion in the normal direction of the first main surface to the second bent portion), sometimes the capacitor element contacts the second bent portion (the third cathode lead portion), and it becomes difficult to place the capacitor element on the first cathode lead portion.

[0029] Furthermore, when there is a gap portion between the fourth cathode lead portion and the second main surface where the conductive adhesive material is not interposed, if the height of the gap portion is too high, the width between the upper end of the fourth cathode lead portion and the second main surface may become narrower due to processing errors, making it difficult to completely fill the gap portion with the outer casing. Furthermore, the outer casing may be easily separated from the capacitor element through the gap portion, causing cracks.

[0030] Therefore, in consideration of the above, the height h of the fourth cathode lead portion is preferably equal to or less than the height H. The height h may be equal to or less than 1 / 2, equal to or less than 1 / 3, or equal to or less than 1 / 4 of the height H.

[0031] Similarly, when the fifth cathode lead is provided, the height of the fifth cathode lead may be such that the height h2 in the normal direction of the first main surface when the first main surface is used as a reference is higher than the thickness of the conductive adhesive material between the first cathode lead and the first main surface, and may be 2 or more times or 3 or more times the height of the conductive adhesive. In addition, the height h2 may be such that it is less than the height H in the normal direction of the first main surface from the first cathode lead to the portion of the third cathode lead that is not exposed from the outer casing, and may be less than 1 / 2, 1 / 3, or 1 / 4 of the height H.

[0032] Regarding the separation distance between the 4th cathode lead portion and the 2nd main surface and / or the separation distance between the 5th cathode lead portion and the 3rd main surface, as long as the gap caused by the separation can be filled with the constituent material of the outer casing, the gap can be designed to be wider than the width to which the material can flow in, taking into account the type of constituent material.

[0033] The anode portion may include, for example, an anode body and an anode wire. The anode body is disposed on the inner side of the cathode portion, and the anode wire extends from the anode body to the outer side of the cathode portion. In this case, the anode wire may be electrically connected to an anode lead terminal on the opposite side to the second cathode lead portion (i.e., the opposite side to the fourth main surface). The anode lead terminal may include, for example, a first anode lead portion extending parallel to the first main surface and in contact with the anode wire, and a second anode lead portion exposed from the outer casing and bent from the first anode lead portion to extend along the outer surface of the outer casing. In the second anode lead portion, an electrical connection is made to an external terminal (anode electrode).

[0034] In this case, for the same reason as above, in order to facilitate placement of the capacitor element on the first cathode lead portion, the height h of the fourth cathode lead portion may be lower than the height H2 from the first cathode lead portion to the anode line in the normal direction of the first main surface. Similarly, in order to facilitate placement of the capacitor element on the first cathode lead portion, the height h2 of the fifth cathode lead portion may be lower than the height H2 from the first cathode lead portion to the anode line.

[0035] The first anode lead portion may be on the same plane as the portion of the third cathode lead portion that is not exposed from the outer casing. Typically, a lead frame in which the anode lead terminal and the cathode lead terminal are continuous is bent, a capacitor element is placed on the lead frame, and after being sealed with an outer casing, the lead frame is cut to separate the anode lead terminal and the cathode lead terminal, thereby manufacturing an electrolytic capacitor. In this case, a lead frame is used in which a plate is punched into a desired shape. In this case, a portion of a lead frame constituting a cathode lead terminal is bent to form the first, second, fourth, and fifth cathode lead portions, and the third cathode lead portion, which is the remaining portion that has not been bent, is on the same plane as the first anode lead portion.

[0036] In addition, the cathode lead terminal may have a structure in which the second cathode lead portion and the third cathode lead portion are not provided, and the first cathode lead portion is directly electrically connected to the external terminal or the cathode electrode. In addition, the second bent portion may not be provided in the outer casing, and the second cathode lead portion exposed from the outer casing may be bent along the outer surface of the outer casing.

[0037] Hereinafter, an electrolytic capacitor according to an embodiment of the present invention will be described with reference to the drawings. In this embodiment, the anode portion includes an anode body and an anode wire extending from the anode body, and the anode wire is joined to an anode lead terminal, but the present invention is not limited thereto.

[0038] Figure 1A 1 is a cross-sectional view schematically showing an electrolytic capacitor 100 according to an embodiment of the present invention, schematically showing states of a capacitor element, an anode lead terminal, and a cathode lead terminal. Figure 1B yes Figure 1A Cross-sectional view at line X1-X2. Figure 2 1 is a schematic cross-sectional view of a capacitor element 10 used in an electrolytic capacitor.

[0039] The electrolytic capacitor 100 includes a capacitor element 10 having an anode portion 6 and a cathode portion 7, an outer casing 11, an anode lead terminal 13 electrically connected to the anode portion 6, and a cathode lead terminal 14 electrically connected to the cathode portion 7. The outer casing 11 covers the capacitor element 10 in a state where a portion of the anode lead terminal 13 and the cathode lead terminal 14 are exposed. The anode portion 6 includes an anode body 1 and an anode wire 2 extending from the anode body 1, and the anode wire 2 is electrically connected to the anode lead terminal 13.

[0040] The cathode portion 7 covers the anode body 1 via the dielectric layer 3. The outer shape of the anode body 1 is a substantially rectangular parallelepiped, and corresponding to the outer shape of the anode body 1, the outer surface of the cathode portion 7 has a first main surface S1, a second main surface S2 sharing a side with the first main surface S1, a third main surface S3 sharing a side with the first main surface S1 and located on the opposite side of the second main surface S2, a fourth main surface S4 orthogonal to the first to third main surfaces, and a fifth main surface S5 on the opposite side of the first main surface. On the opposite side of the fourth main surface S4, the anode wire 2 protrudes from the anode body 1.

[0041] The cathode lead terminal 14 includes a first cathode lead portion 14 a , a second cathode lead portion 14 b , a third cathode lead portion 14 c , a fourth cathode lead portion 14 d , and a fifth cathode lead portion 14 e .

[0042] The first cathode lead portion 14a faces the first main surface S1 of the cathode portion 7. The first cathode lead portion 14a is electrically connected to the cathode portion 7 via the conductive adhesive material 12 interposed between the first cathode lead portion 14a and the first main surface S1.

[0043] like Figure 1A as well as Figure 1B As shown in FIG. 1 , the second cathode lead portion 14b, the fourth cathode lead portion 14d, and the fifth cathode lead portion 14e are bent from the first cathode lead portion 14a at different locations, and stand upright and extend in a direction intersecting the first main surface S1. The second cathode lead portion 14b extends in a direction along a surface intersecting the first main surface S1, the second main surface S2, and the third main surface S3 (in a direction along a plane intersecting the first main surface S1, the second main surface S2, and the third main surface S3). Figure 1AIn the example of FIG. 1 , in the direction along the fourth main surface S4), at the first bent portion 14X, it is bent and extended from the first cathode lead portion 14a. The fourth cathode lead portion 14d is bent and extended from the first cathode lead portion 14a in the direction along the second main surface S2. The fifth cathode lead portion 14e is bent and extended from the first cathode lead portion 14a in the direction along the third main surface S3. Therefore, a portion of each of the first main surface S1 and the second to fourth main surfaces S2 to S4 of the cathode portion 7 is covered by the cathode lead terminal 14.

[0044] The fourth cathode lead portion 14d and the fifth cathode lead portion 14e can accurately position the capacitor element when it is placed on the first cathode lead portion 14a. The height h of the fourth cathode lead portion 14d based on the first cathode lead portion 14a and the height h2 of the fifth cathode lead portion 14e based on the first cathode lead portion 14a are both less than the height H from the first cathode lead portion 14a to the portion of the third cathode lead portion 14c that is not exposed from the outer casing 11. The heights h and h2 may be lower than the height H2 from the first cathode lead portion 14a to the anode wire 2 in the normal direction of the first main surface S1 when the capacitor element is placed.

[0045] The third cathode lead portion 14c is further bent from the second cathode lead portion 14b at the second bent portion 14Y, and extends in the direction along the first main surface S1. A portion of the third cathode lead portion 14c is exposed from the outer casing 11. The portion of the third cathode lead portion 14c exposed from the outer casing 11 extends in the direction along the fourth main surface S4, then extends in the direction along the fifth main surface S5, and extends along the outer casing 11.

[0046] The anode lead terminal 13 includes a first anode lead portion 13a and a second anode lead portion 13b. The first anode lead portion 13a extends in a direction along the first main surface S1 of the cathode portion 7 and contacts the anode wire 2. The second anode lead portion 13b is a portion of the anode lead terminal 13 that is exposed from the outer casing 11, is bent from the first anode lead portion 13a, extends in a direction along the fourth main surface S4 on the opposite side of the third cathode lead portion 14c, and then extends in a direction along the fifth main surface S5, and extends along the outer casing 11.

[0047] Usually, the outer surface of the outer casing on the fifth main surface S5 side where the exposed portions of second anode lead 13b and third cathode lead 14c are provided is the bottom surface of the electrolytic capacitor. Second anode lead 13b and third cathode lead 14c are electrically connected to external terminals, respectively, and the electrolytic capacitor is electrically connected.

[0048] like Figure 1BAs shown, the fourth cathode lead portion 14d is not in direct contact with the second main surface S2, and the fourth cathode lead portion 14d is separated from the second main surface S2. Similarly, the fifth cathode lead portion 14e is not in direct contact with the third main surface S3, and the fifth cathode lead portion 14e is separated from the third main surface S3. On the side of the fourth cathode lead portion 14d close to the first main surface S1, the conductive adhesive material 12 is interposed in the gap between the fourth cathode lead portion 14d and the second main surface S2. In addition, on the side of the fifth cathode lead portion 14e close to the first main surface S1, the conductive adhesive material 12 is interposed in the gap between the fifth cathode lead portion 14e and the third main surface S3. As a result, the reliability of the electrical connection between the cathode lead terminal and the capacitor element 10 can be improved.

[0049] On the other hand, on the side of the fourth cathode lead portion 14d away from the first main surface S1, the gap between the fourth cathode lead portion 14d and the second main surface S2 is filled with the constituent material of the outer casing 11. Similarly, on the side of the fifth cathode lead portion 14e away from the first main surface S1, the gap between the fifth cathode lead portion 14e and the third main surface S3 is filled with the constituent material of the outer casing 11. As a result, the adhesion between the outer casing and the capacitor element is improved, and the effect of suppressing the intrusion of air and the like into the capacitor element is improved. Therefore, the performance degradation of the electrolytic capacitor over time can be suppressed, and high reliability can be maintained.

[0050] Hereinafter, each component of the electrolytic capacitor according to the present embodiment will be described in detail.

[0051] (Anode)

[0052] Anode portion 6 includes anode body 1 and anode wire 2 extending from one surface of anode body 1 and electrically connected to anode lead terminal 13 .

[0053] The anode body 1 is, for example, a porous sintered body of a rectangular parallelepiped obtained by sintering metal particles. As the above-mentioned metal particles, particles of valve metals such as titanium (Ti), tantalum (Ta), and niobium (Nb) can be used. For the anode body 1, one or more metal particles can be used. The metal particles can also be an alloy composed of two or more metals. For example, an alloy containing a valve metal and silicon, vanadium, boron, etc. can be used. In addition, a compound containing a valve metal and a typical element such as nitrogen can also be used. Regarding the alloy of the valve metal, the valve metal is used as the main component, and preferably contains more than 50 atomic % of the valve metal.

[0054] The anode wire 2 is made of a conductive material. The material of the anode wire 2 is not particularly limited, and examples thereof include copper, aluminum, and aluminum alloys in addition to the above-mentioned valve-acting metals. A portion 2 b of the anode wire 2 protrudes from the anode body 1 .

[0055] The materials constituting the anode body 1 and the anode wire 2 may be the same or different. The cross-sectional shape of the anode wire 2 is not particularly limited, and examples thereof include a circle, a racetrack shape (a shape consisting of two curves connecting the ends of parallel straight lines and these straight lines), an ellipse, a rectangle, a polygon, etc. Among them, the racetrack shape is particularly preferred in that rolling is suppressed and positioning is easy when welding with the anode lead terminal 13. The diameter of the anode wire 2 (the long diameter in the case of a racetrack shape and an ellipse) is also not particularly limited, but is, for example, not less than 0.1 mm and not more than 1.0 mm.

[0056] A dielectric layer 3 is formed on the surface of the anode body 1. The dielectric layer 3 is composed of, for example, a metal oxide. As a method for forming a layer composed of a metal oxide on the surface of the anode body 1, for example, a method of immersing the anode body 1 in a chemical conversion solution to anodize the surface of the anode body 1, and a method of heating the anode body 1 in an atmosphere containing oxygen can be cited. The dielectric layer 3 is not limited to the above-mentioned layer composed of a metal oxide, and any dielectric layer can be used as long as it has insulating properties.

[0057] (Cathode)

[0058] Cathode portion 7 includes solid electrolyte layer 4 formed on dielectric layer 3 and cathode layer 5 covering solid electrolyte layer 4 .

[0059] The solid electrolyte layer 4 only needs to be formed to cover at least a portion of the dielectric layer 3. For the solid electrolyte layer 4, for example, a manganese compound or a conductive polymer can be used. As conductive polymers, polypyrrole, polythiophene, polyfuran, polyaniline, polyacetylene, polyphenylene, poly-p-phenylene vinylene, polybenzone, polythiophene ethylene, polyfluorene, polyvinyl carbazole, polyvinyl phenol, polypyridine or their polymer derivatives can be listed. They can be used alone or in combination. In addition, the conductive polymer can also be a copolymer of two or more monomers. Among these, polythiophene, polyaniline, polypyrrole, etc. are preferred in terms of excellent conductivity. Among them, polypyrrole is particularly preferred in terms of excellent waterproofness.

[0060] The solid electrolyte layer 4 containing the above-mentioned conductive polymer is formed, for example, by polymerizing a raw material monomer on the dielectric layer 3. Alternatively, it is formed by applying a liquid containing the above-mentioned conductive polymer to the dielectric layer 3. The solid electrolyte layer 4 is composed of one or more solid electrolyte layers. In the case where the solid electrolyte layer 4 is composed of two or more layers, the composition, formation method (polymerization method), etc. of the conductive polymer used for each layer may also be different.

[0061] The cathode layer 5 includes, for example, a carbon layer formed to cover the solid electrolyte layer 4, and a metal paste layer formed on the surface of the carbon layer. The carbon layer includes a conductive carbon material such as graphite and a resin. The metal paste layer includes, for example, metal particles (for example, silver) and a resin. In addition, the structure of the cathode layer 5 is not limited to this structure. The structure of the cathode layer 5 can be any structure as long as it has a current collection function.

[0062] (Anode lead terminal)

[0063] The anode lead terminal 13 is electrically connected to the anode body 1 via the anode wire 2. The material of the anode lead terminal 13 is not particularly limited as long as it is electrochemically and chemically stable and has conductivity, and may be metal or non-metal. Its shape is, for example, a long strip and flat plate. Regarding the thickness of the anode lead terminal (the distance between the main surfaces of the anode lead terminal), from the perspective of low height, it is preferably 25 μm or more and 200 μm or less, and more preferably 25 μm or more and 100 μm or less.

[0064] The first anode lead portion 13a of the anode lead terminal 13 may be joined to the anode wire 2 by a conductive adhesive, solder, resistance welding or laser welding. The conductive adhesive is, for example, a mixture of a thermosetting resin and carbon particles or metal particles described below.

[0065] (Cathode lead terminal)

[0066] The first cathode lead portion 14a of the cathode lead terminal 14 is electrically connected to the cathode portion 7. The material of the cathode lead terminal 14 is not particularly limited as long as it is electrochemically and chemically stable and has conductivity, and it can be metal or non-metal. Its shape is also not particularly limited, for example, it is a long strip and flat plate. Regarding the thickness of the cathode lead terminal, from the perspective of low height, it is preferably 25 to 200 μm, and more preferably 25 to 100 μm. The first cathode lead portion 14a is bonded to the cathode portion 7, for example, via a conductive adhesive material 12. The fourth cathode lead portion 14d and the fifth cathode lead portion 14e can also be bonded to the cathode portion 7 via a conductive adhesive material 12.

[0067] <Exterior body>

[0068] The outer casing 11 is provided to electrically insulate the anode lead terminal 13 and the cathode lead terminal 14, and is made of an insulating material. The outer casing 11 contains, for example, a cured product of a thermosetting resin. Examples of the thermosetting resin include epoxy resins, phenolic resins, silicone resins, melamine resins, urea resins, alkyd resins, polyurethanes, polyimides, and unsaturated polyesters.

[0069] 《Method for manufacturing electrolytic capacitor》

[0070] An example of a method for manufacturing electrolytic capacitor 100 according to the present embodiment will be described.

[0071] 1) Preparation process

[0072] First, capacitor element 10 is prepared.

[0073] The valve metal particles and the anode wire 2 are placed in a mold in such a way that a part of the anode wire 2 is embedded in the valve metal particles, and then sintered in a vacuum to produce the anode part 6 in which the other part of the anode wire 2 is embedded in the porous sintered body from one side. The pressure during the press molding is not particularly limited. The valve metal particles may also be mixed with a binder such as polyacrylic carbonate as needed.

[0074] Then, the dielectric layer 3 is formed on the anode body 1. Specifically, the anode body 1 is immersed in a formation tank filled with an electrolytic aqueous solution (for example, a phosphoric acid aqueous solution), and the portion of the anode wire 2 drawn out from the anode body 1 is connected to the anode of the formation tank, and anodization is performed, thereby forming a dielectric layer 3 composed of an oxide film of a valve action metal on the surface of the anode body 1. The electrolytic aqueous solution is not limited to a phosphoric acid aqueous solution, and nitric acid, acetic acid, sulfuric acid, etc. can be used.

[0075] Next, solid electrolyte layer 4 is formed. In this embodiment, a process of forming solid electrolyte layer 4 including a conductive polymer is described.

[0076] Regarding the solid electrolyte layer 4 containing a conductive polymer, for example, by impregnating the anode body 1 forming the dielectric layer 3 with a monomer or an oligomer, and then polymerizing the monomer or the oligomer by chemical polymerization or electrolytic polymerization, or by impregnating the anode body 1 forming the dielectric layer 3 with a solution or a dispersion of the conductive polymer and drying it, at least a portion of the dielectric layer 3 is formed.

[0077] Finally, a cathode layer 5 composed of a carbon layer 5a and a metal paste layer 5b is formed by sequentially applying a carbon paste and a silver paste on the surface of the solid electrolyte layer 4. The structure of the cathode layer 5 is not limited thereto, and any structure may be used as long as it has a current collecting function.

[0078] Through the above method, capacitor element 10 can be prepared.

[0079] Second, the anode lead terminal 13 and the cathode lead terminal 14 are prepared.

[0080] A conductive plate is punched out into a shape that follows the outer shapes of the anode lead terminal and the cathode lead terminal.

[0081] Make the cathode lead terminal after punching as Figure 1A as well as Figure 1B The first cathode lead portion 14a, the second cathode lead portion 14b, the fourth cathode lead portion 14d and the fifth cathode lead portion 14e are bent as shown. The bent portion is formed by, for example, bending. In this state, the anode lead terminal 13 including the first anode lead portion 13a and the remaining portion of the cathode lead terminal including the third cathode lead portion 14c are on the same surface. In addition, the heights of the fourth cathode lead portion 14d and the fifth cathode lead portion 14e based on the first cathode lead portion 14a are both less than the height H from the first cathode lead portion 14a to the third cathode lead portion 14c, so the fourth cathode lead portion 14d and the fifth cathode lead portion 14e do not protrude from the main surface of the third cathode lead portion 14c.

[0082] (2) Lead frame bonding process

[0083] The conductive adhesive material 12 is applied to a predetermined position of the cathode layer 5 (cathode portion 7).

[0084] The anode lead terminal 13 and the cathode lead terminal 14 are arranged at predetermined positions, and the capacitor element 10 is placed in a space surrounded by the first anode lead portion 13a, the first cathode lead portion 14a, the second cathode lead portion 14b, the fourth cathode lead portion 14d, and the fifth cathode lead portion 14e in such a manner that the anode wire 2 contacts the first anode lead portion 13a of the anode lead terminal 13. At this time, the fourth cathode lead portion 14d and the fifth cathode lead portion 14e do not protrude from the main surface of the third cathode lead portion 14c, and therefore do not hinder the movement of the capacitor element 10 when placed.

[0085] Then, the contact portion of the anode wire 2 and the anode lead terminal (first anode lead portion) is joined by laser welding, resistance welding, or the like. At this time, at least a portion of the cathode lead terminal 14 (first cathode lead portion 14a) is bonded to the cathode layer 5 via the conductive adhesive material 12. During bonding, a portion of the conductive adhesive material 12 may be present between the fourth cathode lead portion 14d and / or the fifth cathode lead portion 14e and the cathode layer 5 (cathode portion 7). By increasing the amount of conductive adhesive material 12 applied, a portion of the conductive adhesive material can overflow from the space between the first cathode lead portion 14a and the cathode layer 5, and the overflowed amount is between the fourth cathode lead portion 14d and / or the fifth cathode lead portion 14e and the cathode layer 5 (cathode portion 7).

[0086] (3) Sealing process

[0087] The capacitor element 10 and the resin (material of the outer casing 11, such as uncured thermosetting resin and filler) connected to the anode lead terminal 13 and the cathode lead terminal are placed in a mold, and the capacitor element 10 is sealed by transfer molding, compression molding, etc. The molding conditions are not particularly limited, as long as the time and temperature conditions are appropriately set in consideration of the curing temperature of the thermosetting resin used. At this time, a portion of the anode lead terminal and a portion of the third cathode lead portion 14c of the cathode lead terminal 14 are exposed from the mold. As a result, a portion of the anode lead terminal 13 and a portion of the third cathode lead portion 14c are exposed from the outer casing 11. The exposed portion of the anode lead terminal from the outer casing 11 constitutes the second anode lead portion 13b.

[0088] Then, the second anode lead portion 13b and a portion of the third cathode lead portion 14c exposed from the outer casing are bent along the outer surface of the outer casing in a direction away from the first cathode lead portion 14a, and further bent along the outer surface of the outer casing opposite to the first cathode lead portion 14a with the anode portion sandwiched therebetween. Through this process, the cathode lead terminal is bent from the direction along the first main surface S1 to the direction along the fourth main surface S4, and further bent from the direction along the fourth main surface to the direction along the fifth main surface.

[0089] The electrolytic capacitor 100 can be manufactured by the above method.

[0090] Industrial Applicability

[0091] The electrolytic capacitor according to the present invention has excellent connection reliability and low resistance and can therefore be used in a variety of applications.

[0092] Explanation of symbols

[0093] 100: electrolytic capacitor;

[0094] 10: Capacitor components;

[0095] 1: Anode body;

[0096] 2: Anode wire;

[0097] 3: Dielectric layer;

[0098] 4: solid electrolyte layer;

[0099] 5: cathode layer;

[0100] 6: Anode part;

[0101] 7: cathode part;

[0102] 11: Exterior body;

[0103] 12: Conductive adhesive material;

[0104] 13: Anode lead terminal;

[0105] 13a: first anode lead portion;

[0106] 13b: second anode lead portion;

[0107] 14: cathode lead terminal;

[0108] 14a: first cathode lead portion;

[0109] 14b: second cathode lead portion;

[0110] 14c: 3rd cathode lead portion;

[0111] 14d: 4th cathode lead portion;

[0112] 14e: 5th cathode lead portion;

[0113] 14X: 1st bending part;

[0114] 14Y: Second bending portion.

Claims

1. An electrolytic capacitor comprising: A capacitor element having an anode portion and a cathode portion; a cathode lead terminal electrically connected to the cathode portion; an anode lead terminal electrically connected to the anode portion; and an outer casing covering the capacitor element while partially exposing the cathode lead terminal; The cathode portion includes a solid electrolyte layer containing a conductive polymer and a cathode layer covering the solid electrolyte layer. The anode portion includes an anode body and an anode wire extending from the anode body and electrically connected to the anode lead terminal. The capacitor element has a first main surface, a second main surface sharing a side with the first main surface, and a third main surface sharing a side with the first main surface and located on the opposite side to the second main surface. The cathode lead terminal has: a first cathode lead portion facing the first main surface of the capacitor element; a second cathode lead portion bent from the first cathode lead portion and extending in a direction along a surface intersecting the first main surface, the second main surface, and the third main surface; and a third cathode lead portion that is bent from the second cathode lead portion at the first bent portion and extends in a direction along the first main surface, is exposed from the outer casing, is further bent, and extends along an outer surface of the outer casing, The anode lead terminal has: a first anode lead portion extending in a direction along the first main surface and in contact with the anode wire; and a second anode lead portion exposed from the outer casing, bent from the first anode lead portion and extending along the outer surface of the outer casing, The first connection surface of the anode lead terminal connected to the anode line and the second connection surface of the first cathode lead portion connected to the cathode layer face the same direction. The first anode lead portion and the third cathode lead portion that are not exposed from the outer casing are on the same plane, A height H2 from the first cathode lead portion to the anode lead in the normal direction to the first main surface is greater than a height H from the first cathode lead portion to a portion of the third cathode lead portion not exposed from the exterior body in the normal direction to the first main surface.

2. The electrolytic capacitor according to claim 1, wherein: The cathode lead terminal further comprises: a fourth cathode lead portion bent from the first cathode lead portion at a position different from the first bent portion and extending along the second main surface; A height h of the fourth cathode lead portion in the normal direction of the first main surface is smaller than a height H2 from the first cathode lead portion to the anode line in the normal direction of the first main surface.

3. The electrolytic capacitor according to claim 1, wherein: The cathode lead terminal further comprises: a fourth cathode lead portion bent from the first cathode lead portion at a position different from the first bent portion and extending along the second main surface; A height h of the fourth cathode lead portion in the normal direction to the first main surface is less than a height H in the normal direction to the first main surface from the first cathode lead portion to a portion of the third cathode lead portion not exposed from the exterior body.

4. The electrolytic capacitor according to claim 2, wherein: The fourth cathode lead portion extends along the second main surface of the capacitor element in a state of being separated from the second main surface.

5. The electrolytic capacitor according to claim 4, wherein: A gap between the second main surface and the fourth cathode lead portion is filled with a constituent material of the exterior package.

6. The electrolytic capacitor according to claim 2, wherein: The cathode portion is electrically connected to the first cathode lead portion via a conductive adhesive material provided between the first main surface and the first cathode lead portion. The conductive adhesive material is also interposed in a gap between the second main surface and the fourth cathode lead portion.

7. The electrolytic capacitor according to claim 6, wherein: The conductive adhesive material interposed in the gap does not exist in a region higher than the fourth cathode lead portion with respect to the first main surface.

8. The electrolytic capacitor according to claim 6, wherein: The height h of the fourth cathode lead portion is greater than a thickness of the conductive adhesive material interposed between the first cathode lead portion and the first main surface.

9. The electrolytic capacitor according to claim 6, wherein: A region of the gap between the fourth cathode lead portion and the second main surface that is not filled with the conductive adhesive material is filled with a constituent material of the exterior package.

10. The electrolytic capacitor according to claim 1, wherein: The cathode lead terminal further includes: a fifth cathode lead portion bent from the first cathode lead portion at a position different from the first bent portion and extending along the third main surface; The height of the fifth cathode lead portion in the normal direction of the first main surface is equal to or less than the height H.

11. The electrolytic capacitor according to claim 1, wherein: The exposed portion of the third cathode lead portion exposed from the outer casing is bent in a direction away from the first main surface, and then bent and extended along the outer casing.

12. The electrolytic capacitor according to claim 1, wherein: The exposed portion of the third cathode lead portion exposed from the outer casing is bent in a direction away from the first main surface and then bent and extended along the outer casing. The anode wire is electrically connected to the anode lead terminal on the opposite side of the second cathode lead portion.

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