Solid electrolytic capacitors

Abstract

This invention provides a solid electrolytic capacitor that can improve operational reliability over a wide temperature range. [Solution] The solid electrolytic capacitor 100 comprises a capacitor element 10 including an anode portion 6 and a cathode portion 7, an anode lead frame 20 electrically connected to the anode portion 6, a cathode lead frame 30 electrically connected to the cathode portion 7, and an outer casing 40. The outer casing has an outer casing bottom surface 40b and an outer casing top surface 40a. The first cathode surface 7a on the side of the cathode portion closer to the outer casing top surface and the cathode lead frame are bonded together by a conductive adhesive 50. The first cathode surface has a first convex shape toward the cathode lead frame. The angle between the first anode surface 6a on the side of the anode portion closer to the outer casing top surface and the outer casing top surface 40a is less than 1.4°.

Description

Technical Field

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[0001] The present disclosure relates to a solid electrolytic capacitor.

Background Art

[0002] Patent Document 1 proposes "a solid electrolytic capacitor including an anode body made of a valve action metal from which an anode lead is drawn out, having a porous surface, a dielectric layer formed on the surface of the anode body, a solid electrolyte layer made of a conductive polymer formed on the surface of the dielectric layer, and a graphite paste layer and a silver paste layer sequentially formed on the surface of the solid electrolyte layer, wherein the silver paste layer has a first silver paste layer and a second silver paste layer, and the adhesive strength of the silver paste constituting the first silver paste layer to the graphite paste layer is greater than the adhesive strength of the silver paste constituting the second silver paste layer to the graphite paste layer." <00,00010>

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] A solid electrolytic capacitor includes lead frames led out from an anode portion and a cathode portion. A part of each lead frame is drawn out to the outside from an exterior body (molded exterior resin) covering the capacitor element.

[0005] Here, when the surface connected to the cathode lead frame of the cathode portion is not flat, the capacitor element tilts inside the exterior body, and one end of the capacitor element is disposed so as to be close to either the bottom surface or the top surface of the exterior body.

[0006] When capacitor elements are positioned at an angle inside the casing in this way, thermal stress is generated by rapid temperature changes, and this uneven distribution of stress makes delamination between the material layers of the solid electrolytic capacitor more likely to occur. [Means for solving the problem]

[0007] One aspect of this disclosure relates to a solid electrolytic capacitor. The solid electrolytic capacitor comprises a capacitor element including an anode portion and a cathode portion, an anode lead frame electrically connected to the anode portion, a cathode lead frame electrically connected to the cathode portion, and an outer casing covering the capacitor element, a part of the anode lead frame, and a part of the cathode lead frame. The outer casing has an outer casing bottom surface on the side to be mounted on a substrate and an outer casing top surface on the side opposite to the outer casing bottom surface. The anode portion has a first anode surface on the side closer to the outer casing top surface and a second anode surface on the side opposite to the first anode surface. The cathode portion has a first cathode surface on the side closer to the outer casing top surface and a second cathode surface on the side opposite to the first cathode surface. The first cathode surface and the cathode lead frame are bonded together by a conductive adhesive. The first cathode surface has a first convex shape toward the cathode lead frame. The angle between the first anode surface and the outer casing top surface is less than 1.4°. [Effects of the Invention]

[0008] According to the solid electrolytic capacitor of this disclosure, even when the first cathode surface connected to the cathode lead frame has a convex shape, the occurrence of delamination between material layers is suppressed by suppressing the uneven distribution of thermal stress, thereby improving operational reliability over a wide temperature range. [Brief explanation of the drawing]

[0009] [Figure 1] This is a cross-sectional view illustrating the configuration of a solid electrolytic capacitor 100 according to one embodiment of the present disclosure. [Figure 2] This is a schematic diagram illustrating the bonding between the capacitor element 10 and the cathode lead frame 30. [Figure 3]This is an explanatory diagram of the inclination of the capacitor element 10 placed inside the outer casing 40. [Figure 4] This is an explanatory diagram of the inclination of the inner portion 31 of the cathode lead frame 30. [Figure 5] This is a bottom view of the solid electrolytic capacitor 100, with the outer casing 40 omitted from the illustration. [Modes for carrying out the invention]

[0010] Examples of solid electrolytic capacitors related to this disclosure are described below. However, this disclosure is not limited to the examples described below. In the following description, specific numerical values ​​and materials may be given as examples, but other numerical values ​​and materials may be applied as long as the effects of this disclosure are achieved.

[0011] 1. Solid electrolytic capacitor The solid electrolytic capacitor according to this disclosure comprises a capacitor element, an anode lead frame, a cathode lead frame, and an outer casing. Solid electrolytic capacitors are usually substantially rectangular in shape overall. In this case, the outer casing is also substantially rectangular in shape. The outer casing has an outer bottom surface on the side that is mounted on the substrate and an outer top surface on the opposite side of the outer bottom surface. Thus, in this disclosure, the term "bottom" is used for the various parts on the side that is mounted on the substrate, and the term "top" is used for the parts on the opposite side. The direction toward the outer bottom surface and outer top surface will be referred to as the "up and down direction." However, depending on the substrate on which the solid electrolytic capacitor is mounted and the orientation of the substrate, the outer bottom surface does not necessarily face downwards, and the outer top surface does not necessarily face upwards.

[0012] 1.1 Capacitor element The capacitor element includes an anode and a cathode.

[0013] 1.1.1 Anode section The anode portion comprises an anode body having a dielectric layer and an anode wire extending from the mounting surface of the anode body. The anode portion has a first anode surface on the side closer to the upper surface of the outer casing and a second anode surface on the opposite side.

[0014] The anode is, for example, a rectangular porous sintered body obtained by sintering metal particles. As the metal particles, valve metal particles such as titanium (Ti), tantalum (Ta), and niobium (Nb) are used. One or more types of metal particles are used for the anode. The metal particles may be an alloy composed of two or more metals. For example, an alloy containing a valve metal with silicon, vanadium, boron, etc. can be used. Alternatively, a compound containing a valve metal with a typical element such as nitrogen may be used. The valve metal alloy preferably has a valve metal as its main component and contains 50 atomic percent or more of the valve metal.

[0015] The anode wire is made of a conductive material. The material of the anode wire is not particularly limited, and examples include copper, aluminum, aluminum alloy, etc., in addition to the valve metal mentioned above. The materials constituting the anode body and the anode wire may be the same or different. The cross-sectional shape of the anode wire is not particularly limited, and examples include circular, track shape (a shape consisting of parallel straight lines and two curves connecting the ends of these lines), elliptical, rectangular, polygonal, etc. Among these, the track shape is preferred because rolling is suppressed and positioning is easier when welding to the anode lead frame. The diameter of the anode wire (the major axis in the case of track shape and elliptical shape) is also not particularly limited, but for example, it is 0.1 mm or more and 1.0 mm or less.

[0016] A dielectric layer is formed on the surface of the anode. The dielectric layer is composed of, for example, a metal oxide. Methods for forming a layer containing a metal oxide on the surface of the anode include, for example, immersing the anode in a chemical solution to anodize the surface of the anode, or heating the anode in an oxygen-containing atmosphere. The dielectric layer is not limited to the layer containing the metal oxide described above, but only needs to have insulating properties.

[0017] 1.1.2 Cathode The cathode portion has a solid electrolyte layer formed on a dielectric layer and a cathode layer covering the surface of the solid electrolyte layer. The cathode portion has a first cathode surface on the side closer to the upper surface of the outer casing and a second cathode surface on the opposite side.

[0018] The solid electrolyte layer may be formed so as to cover at least a part of the dielectric layer. For the solid electrolyte layer, for example, a manganese compound or a conductive polymer is used. Examples of the conductive polymer include polypyrrole, polythiophene, polyfuran, polyaniline, polyacetylene, polyphenylene, polyparaphenylenevinylene, polyacene, polythiophenylene vinylene, polyfluorene, polyvinylcarbazole, polyvinylphenol, polypyridine, or derivatives of these polymers. These may be used alone or in combination of plural kinds. Also, the conductive polymer may be a copolymer of two or more kinds of monomers. Among these, polyphenylene, polyaniline, polypyrrole, etc. are preferable in terms of excellent conductivity. Among them, polypyrrole is preferable in terms of excellent water repellency.

[0019] The solid electrolyte layer containing the above 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 conductive polymer to the dielectric layer 3. The solid electrolyte layer is composed of one layer or two or more layers of solid electrolyte layers. When the solid electrolyte layer is composed of two or more layers, the composition and formation method (polymerization method) of the conductive polymer used for each layer may be different.

[0020] The cathode layer has, for example, a carbon layer formed so as to cover the solid electrolyte layer and a metal paste layer formed on the surface of the carbon layer. The carbon layer contains a conductive carbon material such as graphite and a resin. The metal paste layer contains, for example, metal particles (e.g., silver) and a resin. Note that the configuration of the cathode layer is not limited to this configuration. The configuration of the cathode layer may be any configuration having a current collecting function.

[0021] 1.2 Lead Frame The anode lead frame is electrically connected to the anode portion. The cathode lead frame is electrically connected to the cathode portion.

[0022] 1.2.1 Anode Lead Frame The anode lead frame is electrically connected to the anode body via anode wires. The material of the anode lead frame is not particularly limited as long as it is electrochemically and chemically stable and conductive, and may be metallic or nonmetallic. The anode lead frame is usually a frame-shaped member cut from metal foil, and its shape is, for example, flat. From the viewpoint of reducing the height, the thickness of the anode lead frame (distance between the main surfaces of the anode lead frame) is preferably 25 μm to 200 μm, and more preferably 25 μm to 150 μm.

[0023] The anode lead frame may be joined to the anode wire by conductive adhesive or solder, or by resistance welding or laser welding. The conductive adhesive is, for example, a mixture of a thermosetting resin and carbon particles or metal particles, as described later.

[0024] 1.2.2 Cathode Lead Frame The cathode lead frame is electrically connected to the cathode. The material of the cathode lead frame is not particularly limited as long as it is electrochemically and chemically stable and conductive, and may be metallic or nonmetallic. The cathode lead frame is usually a frame-shaped member cut from metal foil, and its shape is not particularly limited, for example, it may be flat. From the viewpoint of reducing the profile, the thickness of the cathode lead frame is preferably 25 μm to 200 μm, and more preferably 25 μm to 150 μm.

[0025] 1.3 Exterior The casing covers the capacitor element, a portion of the anode lead frame, and a portion of the cathode lead frame. As described above, the casing has a bottom surface on the side that is mounted on the substrate, and an top surface on the side opposite to the bottom surface.

[0026] The outer casing is provided to electrically insulate the anode lead frame and the cathode lead frame, and is made of an insulating material. The outer casing includes, for example, a cured product of a thermosetting resin. Examples of thermosetting resins include epoxy resin, phenolic resin, silicone resin, melamine resin, urea resin, alkyd resin, polyurethane, polyimide, and unsaturated polyester.

[0027] 1.4 Relationship between capacitor element, lead frame, and casing The first cathode surface of the cathode section and the cathode lead frame are bonded together by a conductive adhesive. The first cathode surface has a first convex shape toward the cathode lead frame. The first height of this first convex shape toward the cathode lead frame is not sufficiently small compared to the thickness of the cathode layer. However, the angle between the first anode surface and the top surface of the outer casing is set to less than 1.4°. The first convex shape is formed, for example, by the metal paste layer constituting the cathode layer during the metal paint application process during manufacturing, but is not limited to this. The conductive adhesive is, for example, a heat-curing type with a viscosity of about 5 to 150 Pa·s at 25°C, but is not limited to this. Good conductivity between the cathode section and the cathode lead frame can be obtained by bringing the top of the first convex shape into contact with or as close as possible to the cathode lead frame. However, since contact between the first convex shape and the cathode lead frame may hinder the horizontal arrangement of the capacitor element, it is preferable that the first convex shape does not come into contact with the cathode lead frame.

[0028] The first height H1 corresponds to the difference Δd (=dmx-dmn) between the maximum distance dmx from the first anode surface to the first cathode surface and the minimum distance dmn from the first anode surface to the first cathode surface. Δd is, for example, 1.1 times or more dmn, and can be 5 times or more. However, it is desirable to limit Δd to 2 times or less dmn.

[0029] By setting the angle between the first anode surface and the top surface of the casing to less than 1.4°, the opposing ends of the capacitor elements are positioned within the casing, not too close to either the bottom or top surface, but generally parallel to both. This suppresses the uneven distribution of thermal stress and prevents delamination between the material layers of the solid electrolytic capacitor.

[0030] The anode lead frame and cathode lead frame may be exposed from the casing at a position closer to the top surface of the casing than to the center surface of the casing, such that the first distance between the top surface of the casing and the first cathode surface is equal to the second distance between the second cathode surface (opposite to the first cathode surface of the cathode portion) and the bottom surface of the casing. In other words, the position in which the anode lead frame and cathode lead frame are exposed from the casing is determined so that the capacitor element is centrally located in the vertical direction within the casing. This further significantly suppresses the uneven distribution of thermal stress and prevents delamination between material layers of the solid electrolytic capacitor.

[0031] A conductive adhesive may be placed to fill the gap between the first cathode surface and the cathode lead frame. This ensures that the capacitor element and the cathode lead frame are kept parallel to each other with minimal influence from the first convex shape of the first cathode surface.

[0032] When connecting a first cathode surface, which has a convex shape, to a flat surface of a cathode lead frame, and attempting to set the angle between the cathode lead frame and the top surface of the casing to less than 1.4°, a delicate alignment process may be required. In such cases, it is effective to interpose a fluid conductive adhesive between the cathode lead frame and the first cathode surface, allowing the conductive adhesive to flow and fill the gap between the first cathode surface and the cathode lead frame. When allowing the conductive adhesive to flow, a portion of the first cathode surface and a portion of the cathode lead frame may be brought into direct contact.

[0033] (Configuration / effects of Claim 4) The cathode lead frame has an inner portion, an intermediate portion, and an out-of-frame portion. The inner portion is bonded to the first cathode surface of the cathode portion. The intermediate portion is continuous with the inner portion and is bent toward the side of the capacitor element. The out-of-frame portion is continuous with the intermediate portion and is bent from the intermediate portion and led out to the outside of the outer casing. In this case, it is preferable that the angle between the inner portion and the upper surface of the outer casing is 0.15° or more so that the tip of the inner portion is closer to the first cathode surface. This makes it easier to adjust the orientation of the capacitor element by the flow of the conductive adhesive applied between the first cathode surface and the cathode lead frame.

[0034] The cathode lead frame may have through holes provided near the boundary between the inner and intermediate portions. This helps to suppress adverse effects on the orientation of the capacitor element due to the accumulation of excess conductive adhesive bonded to the first cathode surface.

[0035] The second cathode surface of the cathode portion, closer to the bottom surface of the outer casing, has a second convex shape that points toward the bottom surface of the outer casing. The anchoring effect of the second convex shape suppresses displacement of the capacitor element from its normal position in the direction along the bottom or top surface of the outer casing within the outer casing. The second convex shape is formed by, but is not limited to, the cathode layer (for example, a coated metal paste layer).

[0036] The first height of the first convex-shaped cathode lead frame is preferably smaller than the second height of the second convex-shaped outer casing bottom surface. In other words, the first cathode surface connected to the cathode lead frame should not have an excessively large convex portion, from the viewpoint of suppressing adverse effects on the orientation of the capacitor element. On the other hand, the convex portion of the second cathode surface, which provides an anchoring effect with the outer casing, is preferably larger as long as it does not cause any disadvantage.

[0037] 2. Specific Examples of Solid Electrolytic Capacitors In the following, an example of a solid electrolytic capacitor according to this disclosure will be specifically described with reference to the drawings. The components and processes of the solid electrolytic capacitor in the example described below can be applied to and modified based on the above description. Furthermore, the matters described below may be applied to the above embodiments. Among the components and processes of the solid electrolytic capacitor in the example described below, components and processes that are not essential to the solid electrolytic capacitor according to this disclosure may be omitted. Note that the figures shown below are schematic and do not accurately reflect the actual shape and number of components.

[0038] The solid electrolytic capacitor 100 of this embodiment will now be described. Figure 1 is a cross-sectional view illustrating the configuration of a solid electrolytic capacitor 100 according to one embodiment of the present disclosure. Figure 2 is a schematic diagram illustrating the adhesion between the capacitor element 10 and the cathode lead frame 30. Figure 3 is a diagram illustrating the inclination of the capacitor element 10 arranged inside the housing 40. Figure 4 is a diagram illustrating the inclination of the inner portion 31 of the cathode lead frame 30. Figure 5 is a bottom view of the solid electrolytic capacitor 100 with the housing 40 omitted from the illustration.

[0039] As shown in Figure 1, the solid electrolytic capacitor 100 comprises a capacitor element 10, an anode lead frame 20, a cathode lead frame 30, and an outer casing 40.

[0040] The capacitor element 10 includes an anode portion 6 and a cathode portion 7. The anode portion 6 has an anode body 1 comprising a dielectric layer 3 and an anode wire 2, and has a first anode surface 6a (lower side in Figure 1) and a second anode surface 6b (upper side in Figure 1). The cathode portion 7 has a solid electrolyte layer 4 formed on the dielectric layer 3 and a cathode layer 5 covering the surface of the solid electrolyte layer 4, and has a first cathode surface 7a (lower side in Figure 1) and a second cathode surface 7b (upper side in Figure 1).

[0041] The anode lead frame 20 is electrically connected to the anode section 6. The cathode lead frame 30 is electrically connected to the cathode section 7.

[0042] The outer casing 40 covers the capacitor element 10, a portion of the anode lead frame 20, and a portion of the cathode lead frame 30. The outer casing 40 has an outer casing bottom surface 40b on the side that is mounted on the substrate (upper side in Figure 1) and an outer casing top surface 40a on the opposite side from the outer casing bottom surface 40b (lower side in Figure 1).

[0043] The anode lead frame 20 and cathode lead frame 30 are exposed from the outer casing 40 at a position closer to the outer casing top surface 40a than to the outer casing bottom surface 40b, such that the first distance D1 between the outer casing top surface 40a and the first anode surface 6a is equal to the second distance D2 between the second anode surface 6b and the outer casing bottom surface 40b.

[0044] As shown in Figure 2, the first cathode surface 7a of the cathode portion 7 and the cathode lead frame 30 are bonded together by a conductive adhesive 50. The first cathode surface 7a has a first convex shape 7ax that faces the cathode lead frame 30. The conductive adhesive 50 is arranged to fill the gap between the first cathode surface 7a and the cathode lead frame 30. Although the figure shows the first convex shape 7ax not in contact with the inner portion 31 (described later) of the cathode lead frame 30, there is no problem even if the first convex shape 7ax is in contact with the inner portion 31. However, since contact may hinder the horizontal arrangement of the capacitor element 10, it is preferable that there is no contact.

[0045] Furthermore, the second cathode surface 7b has a second convex shape 7bx that faces the bottom surface 40b of the outer casing. The first height H1 of the first convex shape 7ax toward the cathode lead frame 30 is smaller than the second height H2 of the second convex shape 7bx toward the bottom surface 40b of the outer casing. The first height H1 is, for example, 90% or less of the second height H2, and preferably 50% or less.

[0046] The cathode lead frame 30 has an inner portion 31 that is bonded to the first cathode surface 7a of the cathode portion 7, an intermediate portion 32 that is continuous with the inner portion 31 and bent toward the side of the capacitor element 10, and an extension portion 33 that is continuous with the intermediate portion 32 and bent from the intermediate portion 32 to lead out to the outside of the outer casing 40.

[0047] As shown in Figure 3, it is preferable that the angle θ1 formed by the first anode surface 6a of the capacitor element 10 and the outer casing top surface 40a is less than 1.4°. Furthermore, it is preferable that the angle θ2 formed by the second anode surface 6b of the capacitor element 10 and the outer casing bottom surface 40b is less than 4°.

[0048] As shown in Figure 4, it is preferable that the angle θ between the inner portion 31 and the outer upper surface 40a is 0.15° or more, so that the tip 31a of the inner portion 31 of the cathode lead frame 30 is closer to the first cathode surface 7a.

[0049] As shown in Figure 5, the cathode lead frame 30 has a through hole 34 provided near the boundary between the inner portion 31 and the intermediate portion 32.

[0050] This disclosure is not limited to the embodiments described above, and can be implemented in various forms without departing from its essence. Furthermore, various disclosures can be formed by appropriately combining the multiple components disclosed in the embodiments described above. For example, some components may be removed from all the components shown in the embodiments. The drawings schematically show each component for ease of understanding, and the number of each component shown may differ from the actual number due to the convenience of drawing creation. In addition, each component shown in the embodiments described above is an example and is not particularly limiting, and various modifications are possible without substantially departing from the effects of this disclosure.

[0051] 3. Addendum The above description of embodiments discloses the following technologies. (Technology 1) A capacitor element comprising an anode portion and a cathode portion having a porous sintered body, An anode lead frame electrically connected to the anode portion, A cathode lead frame electrically connected to the cathode portion, The capacitor element, an outer casing covering a part of the anode lead frame and a part of the cathode lead frame, Equipped with, The aforementioned outer casing has an outer casing bottom surface on the side that is mounted on the substrate, and an outer casing top surface on the side opposite to the outer casing bottom surface. The anode portion has a first anode surface on the side closer to the upper surface of the outer casing and a second anode surface on the side opposite to the first anode surface. The cathode portion has a first cathode surface on the side closer to the upper surface of the outer casing and a second cathode surface on the side opposite to the first cathode surface. The first cathode surface and the cathode lead frame are bonded together with a conductive adhesive. The first cathode surface has a first convex shape toward the cathode lead frame, A solid electrolytic capacitor in which the angle between the first anode surface and the outer casing surface is less than 1.4°. (Technology 2) The solid electrolytic capacitor according to Technical 1, wherein the anode lead frame and the cathode lead frame are exposed from the casing at a position closer to the upper surface of the casing than the central surface of the casing, such that the first distance between the upper surface of the casing and the first anode surface is equal to the second distance between the second anode surface and the bottom surface of the casing. (Technology 3) The solid electrolytic capacitor according to Art 1 or 2, wherein the conductive adhesive is arranged to fill the gap between the first cathode surface and the cathode lead frame. (Technology 4) The cathode lead frame is The inner portion that is in contact with the first cathode surface of the cathode portion, The intermediate portion is continuous with the inner portion and is bent toward the side of the capacitor element, A pull-out portion that is continuous with the intermediate portion and is bent from the intermediate portion and led out to the outside of the exterior body. It has, A solid electrolytic capacitor according to any one of the technologies 1 to 3, wherein the angle between the inner part and the outer surface is 0.15° or more, such that the tip of the inner part is closer to the first cathode surface. (Technology 5) The solid electrolytic capacitor according to Technical Reference 4, wherein the cathode lead frame has a through hole provided near the boundary between the inner portion and the intermediate portion. (Technology 6) The solid electrolytic capacitor according to any one of the technologies 1 to 5, wherein the second cathode surface has a second convex shape toward the bottom surface of the outer casing. (Technology 7) The solid electrolytic capacitor according to Technical Reference 6, wherein the first height of the first convex shape toward the cathode lead frame is smaller than the second height of the second convex shape toward the bottom surface of the outer casing. [Industrial applicability]

[0052] This disclosure is applicable to solid electrolytic capacitors. [Explanation of Symbols]

[0053] 1. Anode 2 Anode wires 3. Dielectric layer 4 Solid electrolyte layer 5. Cathode layer 6. Anode section 6a 1st anode surface 6b Second anode surface 7. Cathode section 7a First cathode surface 7ax 1st convex shape 7b Second cathode surface 7bx 2nd convex shape 10 Capacitor element 20 Anode lead frames 30 Cathode Lead Frames 31 Inner part 32 Middle section 33 Drawer section 34 Through holes 40 Exterior 40a Exterior top surface 40b Exterior bottom 50 Conductive adhesive 100 Solid Electrolytic Capacitors

Claims

1. A capacitor element comprising an anode portion and a cathode portion having a porous sintered body, An anode lead frame electrically connected to the anode portion, A cathode lead frame electrically connected to the cathode portion, The capacitor element, an outer casing covering a part of the anode lead frame and a part of the cathode lead frame, Equipped with, The aforementioned outer casing has an outer casing bottom surface on the side that is mounted on the substrate, and an outer casing top surface on the side opposite to the outer casing bottom surface. The anode portion has a first anode surface on the side closer to the upper surface of the outer casing and a second anode surface on the side opposite to the first anode surface. The cathode portion has a first cathode surface on the side closer to the upper surface of the outer casing and a second cathode surface on the side opposite to the first cathode surface. The first cathode surface and the cathode lead frame are bonded together with a conductive adhesive. The first cathode surface has a first convex shape toward the cathode lead frame, A solid electrolytic capacitor in which the angle between the first anode surface and the outer casing surface is less than 1.4°.

2. The solid electrolytic capacitor according to claim 1, wherein the anode lead frame and the cathode lead frame are exposed from the casing at a position closer to the upper surface of the casing than to the central surface of the casing, such that the first distance between the upper surface of the casing and the first anode surface is equal to the second distance between the second anode surface and the bottom surface of the casing.

3. The solid electrolytic capacitor according to claim 1 or 2, wherein the conductive adhesive is arranged to fill the gap between the first cathode surface and the cathode lead frame.

4. The cathode lead frame is The inner portion that is in contact with the first cathode surface of the cathode portion, The intermediate portion is continuous with the inner portion and is bent toward the side of the capacitor element, A pull-out portion that is continuous with the intermediate portion and is bent from the intermediate portion and led out to the outside of the exterior body. It has, The solid electrolytic capacitor according to claim 1 or 2, wherein the angle between the inner part and the outer surface is 0.15° or more, such that the tip of the inner part is closer to the first cathode surface.

5. The solid electrolytic capacitor according to claim 4, wherein the cathode lead frame has a through hole provided near the boundary between the inner portion and the intermediate portion.

6. The solid electrolytic capacitor according to claim 1 or 2, wherein the second cathode surface has a second convex shape toward the bottom surface of the outer casing.

7. The solid electrolytic capacitor according to claim 6, wherein the first height of the first convex shape toward the cathode lead frame is smaller than the second height of the second convex shape toward the bottom surface of the outer casing.

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