Solid electrolytic capacitor element and solid electrolytic capacitor

Abstract

The disclosed solid electrolytic capacitor element (12) is provided with an anode part (13) disposed on one end side and a cathode part (14) disposed on the other end side. The cathode part (14) has a pair of main surfaces (15), a pair of side surfaces (16) connecting the pair of main surfaces (15) and extending in a direction connecting one end and the other end, and a first end surface (18) connecting the pair of main surfaces (15) and located at the other end. At least one side surface (16) has at least one recess (17) including a first end (17a) on one end side and a second end (17b) on the other end side. The distance (D1) between the first end surface (18) and the second end section (17b) is 0.05 L1 or more, where L1 is the distance between one end and the other end. As a result, the airtightness of the solid electrolytic capacitor can be improved.

Description

Technical Field

[0001] The present disclosure relates to a solid electrolytic capacitor element and a solid electrolytic capacitor. Background Art

[0002] In the past, an electrolytic capacitor (solid electrolytic capacitor) using a solid electrolyte is known (for example, Patent Document 1). The solid electrolytic capacitor of Patent Document 1 includes a plurality of solid electrolytic capacitor elements (hereinafter also referred to as elements) each having an anode portion and a cathode portion. A notch portion is formed at the end of the cathode portion of each element. The solid electrolytic capacitor also includes a cathode terminal having a side wall portion abutting against the side of the notch portion, and the side of the notch portion and the side wall portion are electrically connected using a conductive adhesive.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2008-235413 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] However, in the manufacturing process of the solid electrolytic capacitor (especially in the process of stacking multiple components on the cathode terminal), the conductive adhesive that electrically connects the side and side wall of the notch may also contact the part of the cathode terminal that is not desired to be in contact with the adhesive. In the case where such a part is close to the outside of the solid electrolytic capacitor, the airtightness of the solid electrolytic capacitor is easily lost. If the airtightness is lost, there is a concern that air enters the component from the outside of the solid electrolytic capacitor and the component deteriorates. Under such circumstances, one of the purposes of the present disclosure is to improve the airtightness of the solid electrolytic capacitor.

[0008] Solutions for solving problems

[0009] A technical solution disclosed in the present invention relates to a solid electrolytic capacitor element. The solid electrolytic capacitor element includes an anode portion arranged at one end and a cathode portion arranged at the other end, the cathode portion having a pair of main surfaces, a pair of side surfaces connecting the pair of main surfaces and extending in a direction connecting the one end and the other end, and a first end surface connecting the pair of main surfaces and located at the other end, at least one of the side surfaces having at least one recessed portion, the recessed portion including a first end portion at the one end side and a second end portion at the other end side, the distance between the one end and the other end being set to L1, and the distance between the first end surface and the second end being greater than 0.05L1.

[0010] Another technical solution of the present disclosure relates to a solid electrolytic capacitor. The solid electrolytic capacitor includes: the above-mentioned solid electrolytic capacitor element; and a cathode terminal having an opposing surface opposite to the first end surface, the cathode terminal being electrically connected to the cathode portion, the cathode terminal having a side wall portion opposite to the side surface of the cathode portion and at least a portion of which is accommodated in the recessed portion, and the recessed portion and the side wall portion are electrically connected by means of a conductive adhesive.

[0011] Another technical solution disclosed herein relates to a solid electrolytic capacitor. The solid electrolytic capacitor includes a stacked body having a plurality of solid electrolytic capacitor elements stacked on each other, the plurality of solid electrolytic capacitor elements respectively including an anode portion arranged on one end side and a cathode portion arranged on the other end side, the cathode portion having a pair of main surfaces, a pair of side surfaces connecting the pair of main surfaces and extending in a direction connecting the one end and the other end, and a first end surface connecting the pair of main surfaces and located at the other end, in each of the solid electrolytic capacitor elements, at least one of the side surfaces has at least one recessed portion, the recessed portion including a first end portion on the one end side and a second end portion on the other end side, the at least one recessed portion of each of the solid electrolytic capacitor elements being arranged in the stacking direction of the stacked body, and in each of the solid electrolytic capacitor elements, the distance between the one end and the other end is set to L1, and the distance between the first end surface and the second end is greater than 0.05L1.

[0012] Effects of the Invention

[0013] According to the present disclosure, the airtightness of a solid electrolytic capacitor can be improved.

[0014] The novel features of the present invention are described in the appended claims, but the present invention, both in structure and content, together with other objects and features of the application, will be better understood through the following detailed description with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a plan view schematically showing the solid electrolytic capacitor according to the first embodiment.

[0016] Figure 2 It is a front view schematically showing the solid electrolytic capacitor according to the first embodiment.

[0017] Figure 3 It is a plan view schematically showing a solid electrolytic capacitor according to a second embodiment. DETAILED DESCRIPTION

[0018] The following examples illustrate the implementation of the solid electrolytic capacitor element and solid electrolytic capacitor of the present disclosure. However, the present disclosure is not limited to the examples described below. In the following description, specific values ​​and materials are sometimes exemplified, but other values ​​and materials can also be applied as long as the effect of the present disclosure can be obtained. In this specification, the description of "value A ~ value B" includes value A and value B, which can be renamed as "value A or above and value B or below". In the following description, when the lower limit and upper limit of the numerical value related to specific physical properties, conditions, etc. are exemplified, as long as the lower limit is not above the upper limit, any one of the exemplified lower limits and any one of the exemplified upper limits can be arbitrarily combined. In the case of exemplifying multiple materials, one can be selected from them and used alone, or two or more can be combined and used. "Solid electrolytic capacitor" can also be simply renamed as "electrolytic capacitor", and "capacitor" can also be renamed as "capacitor".

[0019] (Solid electrolytic capacitor element)

[0020] The solid electrolytic capacitor element (hereinafter also referred to as element) disclosed in the present invention includes an anode portion arranged at one end and a cathode portion arranged at the other end. The element may also include an insulating portion, which is provided between the anode portion and the cathode portion to electrically insulate the two. The insulating portion may be composed of an insulating tape or an insulating resin, for example.

[0021] The anode portion may be configured to include a portion of the anode body (a portion of one end side based on the insulating portion) of the element and made of a valve-acting metal. The cathode portion may be configured to include a solid electrolyte layer and a cathode layer, which are sequentially formed on the surface of the cathode forming portion which is the remaining portion of the anode body (a portion of the other end side based on the insulating portion). A dielectric layer is provided between the anode body and the solid electrolyte layer. In addition, the cathode portion may not include a cathode layer.

[0022] Examples of the valve metal constituting the anode body include aluminum, tantalum, niobium, titanium, etc. The anode body may be a foil of the valve metal or a sintered body of valve metal particles.

[0023] The dielectric layer is formed at least on the surface of the cathode forming portion which is the remaining portion of the anode body. The dielectric layer may be formed of an oxide (eg, aluminum oxide) formed on the surface of the anode body by a liquid phase method such as anodic oxidation, vapor deposition, or a gas phase method such as atomic layer deposition.

[0024] The solid electrolyte layer is formed on the surface of the dielectric layer. The solid electrolyte layer may contain a conductive polymer. The solid electrolyte layer may also contain a dopant as required.

[0025] As the conductive polymer, known conductive polymers used in solid electrolytic capacitors, such as π-conjugated conductive polymers, can be used. As conductive polymers, for example, polymers with polypyrrole, polythiophene, polyaniline, polyfuran, polyacetylene, polyphenylene, polyphenylene vinylene, polyphenylene and polythiophene vinylene as basic skeletons can be listed. Among them, polymers with polypyrrole, polythiophene or polyaniline as basic skeletons are preferred. The above-mentioned polymers also include homopolymers, copolymers of two or more monomers, and derivatives of these substances (substitutes with substituents, etc.). For example, polythiophene includes poly (3,4-ethylenedioxythiophene) and the like. Conductive polymers can be used alone or in combination of two or more.

[0026] As a dopant, for example, at least one selected from the group consisting of low molecular anions and polyanions is used. As low molecular anions, for example, sulfate ions, nitrate ions, phosphate ions, borate ions, organic sulfonate ions, carboxylate ions, etc. can be listed, and there is no particular restriction. As a dopant that generates organic sulfonate ions, for example, benzenesulfonic acid, p-toluenesulfonic acid and naphthalenesulfonic acid can be listed. As a polyanion, for example, high molecular type polysulfonic acid and high molecular type polycarboxylic acid can be listed. As a high molecular type polysulfonic acid, polyvinyl sulfonic acid, polystyrene sulfonic acid, polyallyl sulfonic acid, polyacryloyl sulfonic acid and polymethacryloyl sulfonic acid can be listed. As a high molecular type polycarboxylic acid, polyacrylic acid, polymethacrylic acid, etc. can be listed. Polyanions also include polyester sulfonic acid and phenolsulfonic acid phenolic resin. However, polyanions are not limited to this.

[0027] If necessary, the solid electrolyte layer may further contain known additives and known conductive materials other than the conductive polymer. Such conductive materials include, for example, at least one selected from the group consisting of conductive inorganic materials such as manganese dioxide and TCNQ complex salts.

[0028] The cathode layer may be composed of a carbon layer formed on the surface of the solid electrolyte layer and a conductor layer formed on the surface of the carbon layer. The conductor layer may be composed of a silver paste. As the silver paste, for example, a composition comprising silver particles and a resin component (binder resin) may be used. As the resin component, a thermoplastic resin may also be used, but a thermosetting resin such as an imide resin or an epoxy resin is preferably used.

[0029] The cathode portion has a pair of main surfaces, a pair of side surfaces, and a first end surface. The pair of side surfaces connect the pair of main surfaces and extend in a direction connecting one end and the other end of the element. The first end surface connects the pair of main surfaces and is located at the other end of the element. The pair of side surfaces and the first end surface may be continuous with each other.

[0030] At least one side has at least one recessed portion, and the recessed portion includes a first end portion at one end side of the element and a second end portion at the other end side of the element. The shape of the recessed portion may be, for example, a square, a rectangle, a circle, a triangle, or a trapezoid, but is particularly preferably an isosceles trapezoid. In addition, at least one side may have only one recessed portion or may have multiple recessed portions. For example, each of the two side surfaces may have one recessed portion.

[0031] The distance between one end and the other end of the element (i.e., the length dimension of the element) is set to L1, and the distance between the first end face of the cathode portion and the second end of the recess (hereinafter also referred to as distance D1) is greater than 0.05L1. In other words, the recess is formed to be separated from the first end face of the cathode portion by more than 0.05L1 (D1≥0.05L1). In the case of using an element having such a recess to make a solid electrolytic capacitor, even if the recess and a portion of the cathode terminal are electrically connected using a conductive adhesive, the adhesive is not easy to contact the portion of the cathode terminal close to the outside of the solid electrolytic capacitor. Therefore, it is possible to prevent the airtightness of the solid electrolytic capacitor from being damaged, thereby improving the airtightness of the solid electrolytic capacitor.

[0032] From the perspective of improving the airtightness of the solid electrolytic capacitor, the distance D1 is preferably greater than 0.05L1. Furthermore, from the perspective of taking into account both the low ESR characteristics obtained by increasing the coating amount of the conductive adhesive and the higher product airtightness, the distance D1 is preferably greater than 0.05L1 and less than 0.50L1, and more preferably greater than 0.05L1 and less than 0.25L1.

[0033] The shape of the recess may be square or rectangular. In this case, a linear edge is formed at the bottom of the recess. The edge can be used as a guide for guiding a part of the cathode terminal, for example.

[0034] The shape of the recess may also be a trapezoid. In this case, a straight edge is formed at the bottom of the recess. The edge can be used, for example, as a guide for guiding a portion of the cathode terminal. Furthermore, in this case, burrs are less likely to be generated when the recess is formed, which can improve the yield of the element. The shape of the recess is particularly preferably an isosceles trapezoid. When the shape of the recess is set to an isosceles trapezoid, compared to the case where the shape is set to a square or a rectangle, in terms of film forming properties near the side of the element, it is easy to uniformly form the solid electrolyte layer and the cathode layer regardless of the manufacturing method of the solid electrolyte layer and the cathode layer, which is suitable for low ESR.

[0035] A pair of side surfaces may each have at least one recess. The number of recesses on one side surface and the number of recesses on the other side surface may be the same or different. For example, it may be considered that each of the pair of side surfaces has one recess.

[0036] The concave portion on one side and the concave portion on the other side may be opposite to each other. The two concave portions being opposite to each other means that the two concave portions are arranged in a straight line in a direction orthogonal to the direction of one end and the other end of the connection element. In this case, the concave portion can be easily used as a guide for guiding a part of the cathode terminal.

[0037] (Solid Electrolytic Capacitors)

[0038] A solid electrolytic capacitor of one embodiment of the present disclosure (hereinafter also referred to as a solid electrolytic capacitor A) includes the above-mentioned solid electrolytic capacitor element (or element) and a cathode terminal. The solid electrolytic capacitor A may include a plurality of elements. The solid electrolytic capacitor A may also include an anode terminal electrically connected to the anode portion of the element and an outer resin covering each component.

[0039] The cathode terminal has an opposing surface opposite to the first end surface of the cathode portion, and the cathode terminal is electrically connected to the cathode portion. The cathode terminal can be electrically connected to the cathode portion by means of a conductive adhesive (e.g., silver paste). The cathode terminal has a side wall portion that is opposite to the side surface of the cathode portion and at least a portion of which is accommodated in the recess. The recess and the side wall portion are electrically connected by means of a conductive adhesive (e.g., silver paste). The constituent material of the cathode terminal is not particularly limited, and for example, it can be copper or a copper alloy.

[0040] According to such a side wall portion, especially when there are multiple elements, the connection distance between the cathode portion and the cathode terminal of each element becomes shorter, and the equivalent series resistance (ESR) of the solid electrolytic capacitor A can be reduced. In addition, since the recessed portion that accommodates at least a portion of the side wall portion is configured to be separated from the first end face of the cathode portion by more than 0.05L1, the conductive adhesive that electrically connects the recessed portion and the side wall portion is not easy to contact the opposite surface. Therefore, the airtightness of the solid electrolytic capacitor A can be suppressed from being damaged, and the airtightness of the solid electrolytic capacitor A can be improved.

[0041] Another embodiment of the solid electrolytic capacitor of the present invention (hereinafter also referred to as solid electrolytic capacitor B) includes a laminate having a plurality of solid electrolytic capacitor elements (or elements) stacked on each other. The structure of each element is the same as the structure of the above-mentioned element. At least one recess of each element is arranged in the stacking direction of the laminate. The solid electrolytic capacitor B may also include a cathode terminal electrically connected to the cathode portion of the element, an anode terminal electrically connected to the anode portion of the element, and an outer resin covering each component.

[0042] The shape of the recess may be square or rectangular. In this case, a linear edge is formed at the bottom of the recess. The edge can be used as a guide for guiding a part of the cathode terminal, for example.

[0043] The shape of the recess may also be a trapezoid. In this case, a straight edge is formed at the bottom of the recess. The edge can be used, for example, as a guide for guiding a portion of the cathode terminal. Furthermore, in this case, burrs are less likely to be generated when the recess is formed, which can improve the yield of the solid electrolytic capacitor B. The shape of the recess is particularly preferably an isosceles trapezoid. When the shape of the recess is set to an isosceles trapezoid, compared to the case where the shape is set to a square or a rectangle, in terms of film forming properties near the side of the element, it is easy to form the solid electrolyte layer and the cathode layer uniformly regardless of the manufacturing method of the solid electrolyte layer and the cathode layer, which is suitable for low ESR.

[0044] In each solid electrolytic capacitor element, a pair of side surfaces may each have at least one recess. The number of recesses on one side surface and the number of recesses on the other side surface may be the same or different. For example, it may be considered that each of the pair of side surfaces has one recess.

[0045] In each solid electrolytic capacitor element, the recessed portion on one side and the recessed portion on the other side may be opposite to each other. The two recessed portions are opposite to each other means that the two recessed portions are arranged in a straight line in a direction orthogonal to the direction connecting one end and the other end of the element. In this case, it is easy to use the recessed portion of each element as a guide to guide a part of the cathode terminal.

[0046] The solid electrolytic capacitor B may further include a cathode terminal having an opposing surface opposite to the first end surface of each solid electrolytic capacitor element, and the cathode terminal is electrically connected to the cathode portion. The cathode terminal may have a side wall portion opposite to the side surface of the cathode portion and at least a portion of which is accommodated in the recess. The recess and the side wall portion are electrically connected by means of a conductive adhesive (e.g., silver paste). The constituent material of the cathode terminal is not particularly limited, and may be, for example, copper or a copper alloy.

[0047] According to such a side wall portion, the connection distance between the cathode portion of each element and the cathode terminal is shortened, and the ESR of the solid electrolytic capacitor B can be reduced. In addition, since the recessed portion that accommodates at least a portion of the side wall portion is configured to be separated from the first end face of the cathode portion by more than 0.05L1, the conductive adhesive that electrically connects the recessed portion and the side wall portion is not easy to contact the opposite surface. Therefore, the airtightness of the solid electrolytic capacitor B can be suppressed from being damaged, and the airtightness of the solid electrolytic capacitor B can be improved.

[0048] Two or more solid electrolytic capacitor elements may also be such that the distance between the first end and the second end of the recess (or the length dimension in the direction connecting one end and the other end of the element) is the same as each other. In particular, from the perspective of preventing the side wall portion and the side of the recess of the element from contacting each other and causing deterioration of the leakage current, it is preferred to satisfy the above-mentioned dimensional relationship as much as possible. Here, the distance of the recess of two or more elements is considered to be the same even if it is slightly different due to manufacturing errors, etc.

[0049] As described above, according to the present disclosure, the airtightness of the solid electrolytic capacitor can be improved by designing the position of the recessed portion of the element. In addition, according to the present disclosure, the ESR of the solid electrolytic capacitor can be reduced.

[0050] Hereinafter, an example of a solid electrolytic capacitor element and a solid electrolytic capacitor disclosed in the present invention will be described in detail with reference to the accompanying drawings. The above-mentioned constituent elements can be applied to the constituent elements of the solid electrolytic capacitor element and the solid electrolytic capacitor of the example described below. The constituent elements of the solid electrolytic capacitor element and the solid electrolytic capacitor of the example described below can be changed based on the above-mentioned description. In addition, the matters described below can also be applied to the above-mentioned embodiment. The constituent elements of the solid electrolytic capacitor element and the solid electrolytic capacitor of the example described below that are not necessary for the solid electrolytic capacitor element and the solid electrolytic capacitor disclosed in the present invention can also be omitted. In addition, the figures shown below are schematic and do not accurately reflect the shape and number of actual components.

[0051] Implementation Method 1

[0052] Embodiment 1 of the present disclosure is described. The solid electrolytic capacitor 10 of the present embodiment is a so-called gull wing type (a type in which each terminal extends from the side of the outer resin along the lower surface) solid electrolytic capacitor, but is not limited to this. For example, the solid electrolytic capacitor 10 may also be a so-called lower surface electrode type (a type in which each terminal is exposed from the lower surface of the outer resin) solid electrolytic capacitor. In addition, the solid electrolytic capacitor elements of the solid electrolytic capacitor 10 of the present embodiment are in the same orientation, but are not limited to this, and a part of the solid electrolytic capacitor elements and the remaining solid electrolytic capacitor elements may be in opposite orientations. In the latter case, the current flowing in a part of the solid electrolytic capacitor elements and the current flowing in the remaining solid electrolytic capacitor elements are in opposite directions to each other, and the magnetic fields of the two currents cancel each other out, thereby being able to reduce the ESL of the solid electrolytic capacitor 10.

[0053] like Figure 1 and Figure 2As shown, solid electrolytic capacitor 10 includes stacked body 11 in which a plurality (six in this example) of solid electrolytic capacitor elements 12 (hereinafter also simply referred to as element 12 ) are stacked, anode terminal 21 , cathode terminal 22 , and exterior resin 23 .

[0054] The plurality of elements 12 each include a Figure 1 The anode portion 13 is arranged on the left end side of the Figure 1 The cathode portion 14 is provided at the right end side in the figure, and the insulating portion 19 is provided between the anode portion 13 and the cathode portion 14 to electrically insulate the two.

[0055] The cathode portion 14 has a pair of main surfaces 15, a pair of side surfaces 16, and a first end surface 18. The pair of side surfaces 16 connect the pair of main surfaces 15 and extend in a direction connecting one end and the other end of the element 12 ( Figure 1 The first end face 18 connects the pair of main faces 15 and is located at the other end of the element 12. The first end face 18 extends in a direction intersecting the first direction (for example, a direction orthogonal to the first direction). The pair of side faces 16 and the first end face 18 are continuous with each other.

[0056] The pair of side surfaces 16 each have a recess 17 including a first end 17a on one end side of the element 12 and a second end 17b on the other end side of the element 12. The shape of the recess 17 in this embodiment is an isosceles trapezoid, but is not limited thereto. The recess 17 of one side surface 16 and the recess of the other side surface 16 are opposite to each other in a direction orthogonal to the first direction. The recess 17 of each element 12 is disposed in the stacking direction ( Figure 1 The side wall portions 22b described later are housed in each recess 17.

[0057] The distance between one end and the other end of the element 12 (i.e., the length dimension of the element 12 in the first direction) is set to L1, and the distance D1 between the first end face 18 of the cathode portion 14 and the second end 17b of the recess 17 is greater than 0.05L1 (D1≥0.05L1). In the present embodiment, the distance L1 is 6.0mm, and the distance D1 is 1.0mm (D1≈0.17L1). In addition, in the present embodiment, the distance D2 in the first direction between the first end 17a and the second end 17b is 1.0mm, and the depth dimension D3 of the recess 17 is 0.3mm. Moreover, in the present embodiment, the length dimension L2 of the bottom of the recess 17 in the first direction is 0.5mm. However, the dimensions described in this paragraph are illustrative after all, and do not limit the present disclosure in any way.

[0058] The distance D2 between the first end 17a and the second end 17b of the recess 17 of two or more elements 12 is the same. In the present embodiment, the distance D2 is equal to each other in all the elements 12. In addition, in the present embodiment, the distance D1 is also equal to each other in all the elements 12, and the depth dimension D3 is also equal to each other. In addition, in the present embodiment, all the elements 12 are manufactured based on a common design, and the dimensions of each part are equal to each other except for manufacturing errors.

[0059] Anode terminal 21 is electrically connected to anode portion 13 of element 12. Anode terminal 21 is connected to anode portion 13 by welding (eg, laser welding or resistance welding). Anode terminal 21 may be made of copper or a copper alloy.

[0060] The cathode terminal 22 has an opposing surface 22a opposing the first end surface 18 of the cathode portion 14 of the element 12, and the cathode terminal 22 is electrically connected to the cathode portion 14. There is a gap filled with an exterior resin 23 between the opposing surface 22a and the first end surface 18. The cathode terminal 22 is electrically connected to the cathode portion 14 by means of a conductive adhesive (not shown). The cathode terminal 22 has a side wall portion 22b opposing the side surface 16 of the cathode portion 14 and at least a portion of which is accommodated in the recess 17. The side wall portion 22b can be formed, for example, by bending a portion of the cathode terminal 22. The recess 17 and the side wall portion 22b are electrically connected by means of a conductive adhesive (not shown). The cathode terminal 22 can be made of copper or a copper alloy.

[0061] In the present embodiment, in the first direction, the width dimension W of the side wall portion 22b is smaller than the length dimension L2 of the bottom of the recess 17 (W<L2). In the present embodiment, the width dimension W is 0.3 mm, but is not limited thereto. In the first direction, the width dimension W may be greater than the length dimension L2.

[0062] The outer resin 23 covers the laminate 11, the anode terminal 21, and the cathode terminal 22 so that a portion of each of the anode terminal 21 and the cathode terminal 22 is exposed. The exposed portion of each of the anode terminal 21 and the cathode terminal 22 functions as an external terminal of the solid electrolytic capacitor 10. The outer resin 23 is made of an insulating resin material.

[0063] Implementation Method 2

[0064] Embodiment 2 of the present disclosure will be described. The shape of recess 17 of solid electrolytic capacitor 10 of this embodiment is different from that of Embodiment 1. Hereinafter, the differences from Embodiment 1 will be mainly described.

[0065] like Figure 3As shown, the shape of the recess 17 of this embodiment is a rectangle. In this embodiment, the distance D2 between the first end 17a and the second end 17b of the recess 17 (i.e., the length dimension of the recess 17 along the first direction) is 1.0 mm, but it is not limited to this. The other structures are the same as those of the above-mentioned embodiment 1.

[0066] Postscript

[0067] According to the description of the above embodiments, the following technology is disclosed.

[0068] (Technology 1)

[0069] A solid electrolytic capacitor element, wherein:

[0070] The solid electrolytic capacitor element includes an anode portion disposed on one end side and a cathode portion disposed on the other end side.

[0071] The cathode portion has a pair of main surfaces, a pair of side surfaces connecting the pair of main surfaces and extending in a direction connecting the one end and the other end, and a first end surface connecting the pair of main surfaces and located at the other end.

[0072] At least one of the side surfaces has at least one recessed portion, the recessed portion including a first end portion on the one end side and a second end portion on the other end side,

[0073] The distance between the one end and the other end is defined as L1, and the distance between the first end surface and the second end portion is equal to or greater than 0.05L1.

[0074] (Technique 2)

[0075] The solid electrolytic capacitor element according to technique 1, wherein

[0076] The shape of the recess is a trapezoid.

[0077] (Technique 3)

[0078] The solid electrolytic capacitor element according to technique 1, wherein

[0079] The shape of the recess is square or rectangular.

[0080] (Technique 4)

[0081] The solid electrolytic capacitor element according to any one of techniques 1 to 3, wherein:

[0082] The pair of side surfaces each have the at least one recessed portion.

[0083] (Technique 5)

[0084] The solid electrolytic capacitor element according to technique 4, wherein:

[0085] The recessed portion of one of the side surfaces and the recessed portion of the other side surface are opposed to each other.

[0086] (Technique 6)

[0087] A solid electrolytic capacitor, wherein:

[0088] The solid electrolytic capacitor includes:

[0089] The solid electrolytic capacitor element according to any one of techniques 1 to 5; and

[0090] a cathode terminal having an opposing surface opposed to the first end surface, the cathode terminal being electrically connected to the cathode portion,

[0091] The cathode terminal has a side wall portion that is opposite to the side surface of the cathode portion and at least a portion of which is received in the recessed portion.

[0092] The recessed portion and the side wall portion are electrically connected via a conductive adhesive.

[0093] (Technique 7)

[0094] A solid electrolytic capacitor, wherein:

[0095] The solid electrolytic capacitor includes a laminate having a plurality of solid electrolytic capacitor elements laminated on each other, each of the plurality of solid electrolytic capacitor elements including an anode portion disposed on one end side and a cathode portion disposed on the other end side.

[0096] The cathode portion has a pair of main surfaces, a pair of side surfaces connecting the pair of main surfaces and extending in a direction connecting the one end and the other end, and a first end surface connecting the pair of main surfaces and located at the other end.

[0097] In each of the solid electrolytic capacitor elements, at least one of the side surfaces has at least one recessed portion, the recessed portion including a first end portion on the one end side and a second end portion on the other end side.

[0098] The at least one recessed portion of each of the solid electrolytic capacitor elements is arranged in a stacking direction of the stacked body,

[0099] In each of the solid electrolytic capacitor elements, a distance between the one end and the other end is defined as L1, and a distance between the first end surface and the second end portion is equal to or greater than 0.05 L1.

[0100] (Technology 8)

[0101] The solid electrolytic capacitor according to technique 7, wherein:

[0102] The shape of the recess is a trapezoid.

[0103] (Technique 9)

[0104] The solid electrolytic capacitor according to technique 7, wherein:

[0105] The shape of the recess is square or rectangular.

[0106] (Technology 10)

[0107] A solid electrolytic capacitor according to any one of techniques 7 to 9, wherein:

[0108] In each of the solid electrolytic capacitor elements, each of the pair of side surfaces has the at least one recessed portion.

[0109] (Technology 11)

[0110] The solid electrolytic capacitor according to technique 10, wherein:

[0111] In each of the solid electrolytic capacitor elements, the recessed portion on one of the side surfaces and the recessed portion on the other side surface are opposed to each other.

[0112] (Technology 12)

[0113] A solid electrolytic capacitor according to any one of Techniques 7 to 11, wherein:

[0114] The solid electrolytic capacitor further includes a cathode terminal having an opposing surface facing the first end surface of each of the solid electrolytic capacitor elements, the cathode terminal being electrically connected to the cathode portion.

[0115] The cathode terminal has a side wall portion that is opposite to the side surface of the cathode portion and at least a portion of which is received in the recessed portion.

[0116] The recessed portion and the side wall portion are electrically connected via a conductive adhesive.

[0117] (Technology 13)

[0118] A solid electrolytic capacitor according to any one of Techniques 7 to 12, wherein:

[0119] The distances between the first end and the second end of the recessed portion of two or more of the solid electrolytic capacitor elements are the same as each other.

[0120] Example

[0121] The solid electrolytic capacitors 10 of Examples 1 to 8 and Comparative Examples 1 to 3 shown below were evaluated for their characteristics. Specifically, the solid electrolytic capacitors 10 of each Example and Comparative Example were evaluated for the rate of occurrence of airtightness failure after a predetermined heat load was applied and the ESR value after the circuit board to which the solid electrolytic capacitor 10 was soldered was subjected to a predetermined heat resistance test.

[0122] The airtightness of the solid electrolytic capacitor 10 was evaluated according to the following steps. That is, for each solid electrolytic capacitor 10, a heat treatment was performed under the same temperature conditions as the reflow soldering process in accordance with IPC / JEDEC J-STD-020D (the maximum temperature was set to 260°C and heated at above 255°C for 30 seconds). A total leakage test was performed after the heat treatment. Specifically, each solid electrolytic capacitor 10 was placed in a small sealed container, and the slight pressure drop caused by the internal pressure in the small sealed container leaking into the outer body was measured. Moreover, the capacitor whose pressure change at this time is larger than the predetermined value is judged to be poorly airtight.

[0123] In addition, 100 solid electrolytic capacitors 10 of each type were prepared and subjected to the above test, and the airtightness failure rate was calculated according to the following formula.

[0124] Airtightness failure rate (%) = 100 × (the number of solid electrolytic capacitors judged to be airtight) / (the number of solid electrolytic capacitors used for testing)

[0125] The ESR of the solid electrolytic capacitor 10 before and after the heat test was evaluated according to the following steps. That is, the ESR value of the solid electrolytic capacitor 10 before the heat test at a frequency of 100kHz was measured using a 4-terminal LCR meter under a temperature environment of 20°C. Next, the rated voltage was applied to the solid electrolytic capacitor 10 at a temperature of 145°C for 1000 hours (heat test). Thereafter, the ESR values ​​after the heat test were measured separately according to the same method as above. Then, the evaluation results were summarized by setting the ESR before the heat test to 100, which was the baseline value. In each embodiment and each comparative example, the number of samples was set to 100.

[0126] 《Example 1》

[0127] Gull-wing type solid electrolytic capacitors 10 were evaluated. The shape of the recess 17 was set to an isosceles trapezoid, and in each element 12, the recess 17 was provided only on one side 16. In each element 12, the length L1 was set to 6.0 mm, the distance D1 was set to 1.0 mm, and the distance D2 was set to 1.0 mm. As a result of the evaluation, the occurrence rate of poor airtightness was 0%, and the ESR after the heat resistance test was 101.

[0128] 《Example 2》

[0129] In each element 12, recessed portions 17 were provided on both side surfaces 16. The other structures were the same as those in Example 1. As a result of evaluation, the rate of occurrence of airtight failure was 0%, and the ESR after the heat resistance test was 101.

[0130] 《Example 3》

[0131] In each element 12, the distance D1 was set to 1.0 mm, and the distance D2 was set to 1.5 mm. The other structures were the same as those in Example 2. As a result of evaluation, the occurrence rate of airtight failure was 0%, and the ESR after the heat resistance test was 101.

[0132] 《Example 4》

[0133] In each element 12, the distance D1 was set to 1.0 mm, and the distance D2 was set to 2.0 mm. The other structures were the same as those in Example 2. As a result of evaluation, the occurrence rate of airtight failure was 0%, and the ESR after the heat resistance test was 101.

[0134] 《Example 5》

[0135] In each element 12, the distance D1 was set to 1.5 mm, and the distance D2 was set to 1.0 mm. The other structures were the same as those in Example 2. As a result of evaluation, the occurrence rate of airtight failure was 0%, and the ESR after the heat resistance test was 101.

[0136] Example 6

[0137] In each element 12, the distance D1 was set to 0.5 mm, and the distance D2 was set to 1.0 mm. The other structures were the same as those in Example 2. As the evaluation results, the occurrence rate of airtight failure was 0%, and the ESR after the heat resistance test was 100.

[0138] 《Example 7》

[0139] In each element 12, the distance D1 was set to 0.3 mm, and the distance D2 was set to 1.0 mm. The other structures were the same as those in Example 2. As a result of evaluation, the occurrence rate of airtight failure was 0%, and the ESR after the heat resistance test was 101.

[0140] 《Example 8》

[0141] In each element 12, the shape of the recess 17 was set to a rectangular shape. In each element 12, the distance D1 was set to 1.0 mm, and the distance D2 was set to 1.0 mm. The other structures were the same as those in Example 2. As the evaluation results, the occurrence rate of airtight failure was 0%, and the ESR after the heat resistance test was 101.

[0142] Comparative Example 1

[0143] Gull-wing type solid electrolytic capacitors were evaluated. In each component, a rectangular notch extending from the first end face to a certain distance was provided on both side surfaces. The length of each component along the first direction was set to 6.0 mm. In each component, the length of the notch along the first direction was set to 1.0 mm. As a result of the evaluation, the rate of occurrence of poor airtightness was 27%, and the ESR after the heat resistance test was 341.

[0144] Comparative Example 2

[0145] In each element, the length of the notch along the first direction was set to 1.5 mm. The other structures were the same as those in Comparative Example 1. As evaluation results, the occurrence rate of airtight failure was 6%, and the ESR after the heat resistance test was 242.

[0146] 《Comparative Example 3》

[0147] In each component, a rectangular notch extending from the first end face to a certain distance was provided only on one side surface. In each component, the length of the notch along the first direction was set to 1.5 mm. The other structures were the same as those in Comparative Example 1. As an evaluation result, the occurrence rate of poor airtightness was 6%, and the ESR after the heat resistance test was 239.

[0148] As described above, the solid electrolytic capacitors 10 of Examples 1 to 8 all had a 0% rate of poor airtightness, and the ESR after the heat resistance test did not substantially increase. On the other hand, the solid electrolytic capacitors of Comparative Examples 1 to 3 had a certain degree of poor airtightness, and the ESR increased significantly after the heat resistance test. Therefore, it can be said that the superiority of Examples 1 to 8 is demonstrated.

[0149] Preferred embodiments of the present disclosure have been described, but the scope of the present disclosure should not be limited by the description. For example, as long as no technical contradiction occurs, the matters described in two or more claims arbitrarily selected from the plurality of claims described in the appended claims can be combined.

[0150] The present invention has been described by the present preferred embodiments, but such disclosure should not be construed in a limiting sense. Various modifications and changes will undoubtedly be apparent to those skilled in the art in the art to which the present invention belongs by reading the above disclosure. Therefore, the appended claims should be interpreted as including all modifications and changes without departing from the true spirit and scope of the present invention.

[0151] Industrial Applicability

[0152] The present disclosure can be applied to a solid electrolytic capacitor element and a solid electrolytic capacitor.

[0153] Description of Reference Numerals

[0154] 10. Solid electrolytic capacitor; 11. Laminated body; 12. Solid electrolytic capacitor element; 13. Anode portion; 14. Cathode portion; 15. Main surface; 16. Side surface; 17. Recessed portion; 17a. First end portion; 17b. Second end portion; 18. First end surface; 19. Insulating portion; 21. Anode terminal; 22. Cathode terminal; 22a. Opposite surface; 22b. Side wall portion; 23. External resin; D1. Distance between the first end surface and the second end portion; D2. Distance between the first end portion and the second end portion; D3. Depth dimension of the recessed portion; L1. Length dimension of the element; L2. Length dimension of the bottom of the recessed portion; W. Width dimension of the side wall portion.

Claims

1. A solid electrolytic capacitor element, wherein: The solid electrolytic capacitor element includes an anode portion disposed on one end side and a cathode portion disposed on the other end side. The cathode portion has a pair of main surfaces, a pair of side surfaces connecting the pair of main surfaces and extending in a direction connecting the one end and the other end, and a first end surface connecting the pair of main surfaces and located at the other end. At least one of the side surfaces has at least one recessed portion, the recessed portion including a first end portion on the one end side and a second end portion on the other end side, The distance between the one end and the other end is defined as L1, and the distance between the first end surface and the second end portion is equal to or greater than 0.05L1.

2. The solid electrolytic capacitor element according to claim 1, wherein The shape of the recess is a trapezoid.

3. The solid electrolytic capacitor element according to claim 1, wherein The shape of the recess is square or rectangular.

4. The solid electrolytic capacitor element according to claim 1, wherein The pair of side surfaces each have the at least one recessed portion.

5. The solid electrolytic capacitor element according to claim 4, wherein: The recessed portion of one of the side surfaces and the recessed portion of the other side surface are opposed to each other.

6. A solid electrolytic capacitor, wherein: The solid electrolytic capacitor includes: The solid electrolytic capacitor element according to any one of claims 1 to 5; and a cathode terminal having an opposing surface opposed to the first end surface, the cathode terminal being electrically connected to the cathode portion, The cathode terminal has a side wall portion that is opposite to the side surface of the cathode portion and at least a portion of which is received in the recessed portion. The recessed portion and the side wall portion are electrically connected via a conductive adhesive.

7. A solid electrolytic capacitor, wherein: The solid electrolytic capacitor includes a laminate having a plurality of solid electrolytic capacitor elements laminated on each other, each of the plurality of solid electrolytic capacitor elements including an anode portion disposed on one end side and a cathode portion disposed on the other end side. The cathode portion has a pair of main surfaces, a pair of side surfaces connecting the pair of main surfaces and extending in a direction connecting the one end and the other end, and a first end surface connecting the pair of main surfaces and located at the other end. In each of the solid electrolytic capacitor elements, at least one of the side surfaces has at least one recessed portion, the recessed portion including a first end portion on the one end side and a second end portion on the other end side. The at least one recessed portion of each of the solid electrolytic capacitor elements is arranged in a stacking direction of the stacked body, In each of the solid electrolytic capacitor elements, a distance between the one end and the other end is defined as L1, and a distance between the first end surface and the second end portion is equal to or greater than 0.05 L1.

8. The solid electrolytic capacitor according to claim 7, wherein: The shape of the recess is a trapezoid.

9. The solid electrolytic capacitor according to claim 7, wherein: The shape of the recess is square or rectangular.

10. The solid electrolytic capacitor according to claim 7, wherein: In each of the solid electrolytic capacitor elements, each of the pair of side surfaces has the at least one recessed portion.

11. The solid electrolytic capacitor according to claim 10, wherein: In each of the solid electrolytic capacitor elements, the recessed portion on one of the side surfaces and the recessed portion on the other side surface are opposed to each other.

12. The solid electrolytic capacitor according to any one of claims 7 to 11, wherein: The solid electrolytic capacitor further includes a cathode terminal having an opposing surface facing the first end surface of each of the solid electrolytic capacitor elements, the cathode terminal being electrically connected to the cathode portion. The cathode terminal has a side wall portion that is opposite to the side surface of the cathode portion and at least a portion of which is received in the recessed portion. The recessed portion and the side wall portion are electrically connected via a conductive adhesive.

13. The solid electrolytic capacitor according to any one of claims 7 to 11, wherein: The distances between the first end and the second end of the recessed portion of two or more of the solid electrolytic capacitor elements are the same as each other.

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