Solid electrolytic capacitor

Abstract

A solid electrolytic capacitor according to an embodiment of the present disclosure is provided with: a capacitor element comprising a positive electrode section and a negative electrode section; an exterior body that seals the capacitor element; a first external electrode that electrically connects to the positive electrode section; and a second external electrode that electrically connects to the negative electrode section. An end surface of at least the positive electrode section or the negative electrode section is exposed from the exterior body and is electrically connected to the first external electrode or the second external electrode. The end surface exposed from the exterior body comprises a conductive region and an insulating region. The insulating region comprises, in at least a part thereof, an adhesive layer, and at least a part of the insulating region is covered by an anchor member.

Description

solid electrolytic capacitor

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

[0002] A solid electrolytic capacitor includes, for example, a capacitor element having an anode portion and a cathode portion, an outer casing that seals the capacitor element, a first external electrode electrically connected to the anode portion, and a second external electrode electrically connected to the cathode portion.

[0003] Patent Document 1 below describes forming a conductive anchor member on a first end surface of an element body by an aerosol deposition (AD) method. Specifically, it describes introducing copper powder (Cu powder) into a carrier gas in an aerosol generator to generate an aerosol, and then spraying the generated aerosol onto the first end surface of the element body to form the conductive anchor member.

[0004] International Publication No. 2024 / 047961

[0005] However, when an aerosol containing copper powder is sprayed onto the first end face of the element body by the AD method or the like, the copper powder may be sparsely attached to the surface of the outer casing, which is mainly composed of insulating resin. In such cases, the anchor member is not sufficiently formed on the first end face of the element body, which may cause peeling between the outer casing and the external electrode.

[0006] Furthermore, if the anchor member is sparsely formed on the surface of the insulating resin, particularly around conductive regions such as the exposed surface of the electrode, peeling may occur between the periphery of the conductive region and the external electrode. As a result, minute gaps may form between the exterior body and the external electrode. When such minute gaps form, oxygen or moisture may penetrate into the interior of the exterior body through the minute gaps. If oxygen penetrates into the interior of the exterior body, the solid electrolyte layer of the capacitor element may deteriorate, resulting in a decrease in capacitance. If moisture penetrates into the interior of the exterior body, the dielectric layer of the capacitor element may deteriorate, resulting in a decrease in voltage resistance and an increase in leakage current.

[0007] Therefore, an object of the present disclosure is to provide a solid electrolytic capacitor that can suppress peeling between the exterior body and the external electrode, particularly in the vicinity of the conductive region.

[0008] One aspect of the present invention relates to a solid electrolytic capacitor comprising: a capacitor element including an anode portion and a cathode portion; an exterior housing that seals the capacitor element; a first external electrode electrically connected to the anode portion; and a second external electrode electrically connected to the cathode portion, wherein at least one of end faces of the anode portion and the cathode portion is exposed from the exterior housing and is electrically connected to the first external electrode or the second external electrode, the end face exposed from the exterior housing has a conductive region and an insulating region, at least a portion of the insulating region has an adhesive layer, and at least a portion of the insulating region is covered with an anchor member.

[0009] According to the present disclosure, it is possible to provide a solid electrolytic capacitor that can suppress peeling between the exterior body and the external electrode, and also to provide a solid electrolytic capacitor that can suppress peeling between the exterior body and the external electrode, particularly around the conductive region.

[0010] 2A is a side cross-sectional view showing the configuration of a capacitor element according to an embodiment of the present disclosure; FIG. 2B is a side cross-sectional view showing the configuration of a capacitor element having a separation member on a lower main surface in the height direction; FIG. 2C is a side cross-sectional view showing the configuration of a capacitor element having a separation member on an upper main surface in the height direction; FIG. 2D is a side cross-sectional view showing the configuration of a solid electrolytic capacitor according to an embodiment of the present disclosure; FIG. 2A is a perspective view of the solid electrolytic capacitor when viewed from the anode portion side in a case where a first external electrode is not attached; FIG. 2A is a perspective view of the solid electrolytic capacitor when viewed from the cathode portion side in a case where a second external electrode is not attached.

[0011] The following describes embodiments of the present disclosure using examples, but the present disclosure is not limited to the examples described below. In the following description, specific numerical values ​​and materials may be used as examples, but other numerical values, materials, etc. may be applied as long as the effects of the present disclosure are obtained. Note that known components may be applied to components characteristic of the present disclosure. In this specification, when a "range between numerical value A and numerical value B" is mentioned, the range includes numerical value A and numerical value B.

[0012] In the following description, when lower and upper limits of numerical values ​​relating to specific physical properties, conditions, etc. are exemplified, any of the exemplified lower limits and any of the exemplified upper limits can be arbitrarily combined, as long as the lower limit is not equal to or greater than the upper limit. When multiple materials are exemplified, one of them may be selected and used alone, or two or more may be used in combination, unless otherwise specified.

[0013] The present disclosure encompasses any combination of two or more features arbitrarily selected from the appended claims, i.e., any combination of two or more features arbitrarily selected from the appended claims can be combined unless a technical contradiction arises.

[0014] A solid electrolytic capacitor according to an embodiment of the present disclosure includes a capacitor element having an anode portion and a cathode portion, an exterior body that seals the capacitor element, a first external electrode electrically connected to the anode portion, and a second external electrode electrically connected to the cathode portion.

[0015] In the solid electrolytic capacitor according to the embodiment of the present disclosure, at least one of the end faces of the anode part and the cathode part is exposed from the outer casing and electrically connected to the first external electrode or the second external electrode. In the solid electrolytic capacitor according to the embodiment of the present disclosure, the end face exposed from the outer casing has a conductive region and an insulating region, and at least a portion of the insulating region has an adhesive layer. In the solid electrolytic capacitor according to the embodiment of the present disclosure, at least a portion of the insulating region is covered with an anchor member.

[0016] In the solid electrolytic capacitor according to the embodiment of the present disclosure, it is important that (i) at least one of the end faces of the anode and cathode parts is exposed from the exterior housing, and the end face exposed from the exterior housing has an insulating region, (ii) the insulating region has at least a portion thereof an adhesive layer, and (iii) at least a portion of the insulating region is covered with an anchor member. In other words, it is important that at least one of the end faces of the anode and cathode parts exposed from the exterior housing has an insulating region having at least a portion thereof an adhesive layer, and at least a portion of the insulating region is covered with the anchor member via the adhesive layer. The reason for this is explained below.

[0017] As described above, a solid electrolytic capacitor includes a capacitor element having an anode portion and a cathode portion, an outer casing that seals the capacitor element, a first external electrode electrically connected to the anode portion, and a second external electrode electrically connected to the cathode portion. The first and second external electrodes are typically attached to the outer casing via a conductive paste. In this case, an anchor member is preferably formed on the attachment surface of at least one of the first and second external electrodes to prevent peeling between the outer casing and at least one of the first and second external electrodes. Hereinafter, the attachment surface of the first external electrode and the attachment surface of the second external electrode will be collectively referred to as the "attachment surface of the external electrode."

[0018] When a metal powder such as copper powder is introduced into a carrier gas to generate an aerosol, and then this aerosol is sprayed to form an anchor member on the attachment surface of an external electrode, i.e., when the anchor member is formed on the attachment surface of an external electrode by the AD method or the like, the metal powder such as copper powder adheres sufficiently to the conductive region because both the metal powder such as copper powder and the conductive region made of a metal (e.g., aluminum) have excellent malleability.

[0019] On the other hand, although the outer casing is typically formed of insulating resin, insulating resin is often less malleable than metal. Here, according to the AD method and the like, metal powder such as copper powder adheres to the insulating resin while penetrating it. However, because metal powder such as copper powder and insulating resin have opposing malleability characteristics, it is difficult to adhere the metal powder such as copper powder to the insulating resin in a state where it is sufficiently embedded. As a result, some of the metal powder such as copper powder may peel off from the insulating resin. In such cases, the metal powder such as copper powder adheres unevenly to the insulating resin. When the metal powder such as copper powder adheres unevenly, the anchor member is formed sparsely on the mounting surface of the external electrode, making it difficult to prevent peeling between the outer casing and the external electrode.

[0020] Furthermore, if the anchor members are sparsely formed on the mounting surface of the external electrode, particularly around the conductive region, it becomes difficult to prevent peeling between the periphery of the conductive region and the external electrode, resulting in the formation of minute gaps between the exterior body and the external electrode. When such minute gaps are formed, oxygen or moisture may penetrate into the interior of the exterior body through the minute gaps. If oxygen penetrates into the interior of the exterior body, the solid electrolyte layer of the capacitor element deteriorates, resulting in a decrease in capacitance. If moisture penetrates into the interior of the exterior body, the dielectric layer of the capacitor element deteriorates, resulting in a decrease in voltage resistance and an increase in leakage current.

[0021] However, in the solid electrolytic capacitor according to the embodiment of the present disclosure, as described above, at least one of the end faces of the anode and cathode parts exposed from the outer casing has an insulating region with an adhesive layer at least partially covering the insulating region, and at least a portion of the insulating region is covered with an anchor member via the adhesive layer. In other words, the solid electrolytic capacitor according to the embodiment of the present disclosure has an insulating region on the attachment surface of the external electrode that can sufficiently retain the material for forming the anchor member, such as metal powder. Therefore, compared to a solid electrolytic capacitor that does not have such an insulating region on the attachment surface of the external electrode, it is possible to prevent the anchor member from being formed sparsely on the attachment surface of the external electrode. This prevents peeling between the outer casing and the external electrode.

[0022] Furthermore, because the insulating region is disposed on at least one of the end surfaces of the anode and cathode components exposed from the exterior housing, sparse formation of anchor members around the conductive region can be suppressed. This suppresses peeling between the periphery of the conductive region and the external electrode, thereby suppressing the formation of minute voids between the exterior housing and the external electrode. This suppresses the intrusion of oxygen or moisture into the interior of the exterior housing through such minute voids, thereby suppressing a decrease in capacitance due to oxygen intrusion and a decrease in voltage resistance or an increase in leakage current due to moisture intrusion.

[0023] Hereinafter, the configuration of a capacitor element and the configuration of a solid electrolytic capacitor according to an embodiment of the present disclosure will be described with reference to the drawings.

[0024] 1A , capacitor element 10 includes anode body 11 extending in first direction D1, a dielectric layer (not shown) covering at least a portion of anode body 11, solid electrolyte layer 12 covering at least a portion of the dielectric layer, and cathode extraction layer 13 covering at least a portion of solid electrolyte layer 12. In capacitor element 10 shown in FIG. 1A , anode body 11 is an anode portion, and solid electrolyte layer 12 and cathode extraction layer 13 form a cathode portion 14. Note that first direction D1 is a direction parallel to a main surface of anode body 11 and also the length direction of anode body 11.

[0025] In capacitor element 10, anode body 11 has a first anode body portion 11a that does not have solid electrolyte layer 12 and is arranged on one side in first direction D1, and a second anode body portion 11b that has solid electrolyte layer 12 and is arranged on the other side in first direction D1. First anode body portion 11a functions as an anode lead portion. Note that in FIG. 1A , for convenience, the boundary between first anode body portion 11a and second anode body portion 11b is indicated by a solid line.

[0026] In the capacitor element 10, the first anode body 11a and the second anode body 11b each have a roughened portion 11c extending from at least one outer surface toward the center in the thickness direction, and a core portion 11d continuous with the roughened portion 11c in the thickness direction. In the first anode body 11a and the second anode body 11b shown in FIG. 1A, the roughened portion 11c is formed so as to extend from each of the outer surfaces toward the center in the thickness direction. That is, in the first anode body 11a and the second anode body 11b shown in FIG. 1A, the core portion 11d is sandwiched between a pair of roughened portions 11c in the thickness direction. The outer surfaces of the first anode body 11a and the second anode body 11b refer to the main surfaces of the first anode body 11a and the second anode body 11b, respectively.

[0027] In the capacitor element 10, the roughened portion 11c of the first anode body 11a has a thin portion 11c1 that is thinner than the roughened portion 11c of the second anode body 11b. The thin portion 11c1 typically has a smaller porosity than the roughened portion 11c of the second anode body 11b. The porosity of the thin portion 11c1 may be, for example, 40% or less, 30% or less, or 20% or less. The lower limit of the porosity of the thin portion 11c1 is not particularly limited as long as it is greater than 0%. The porosity of the thin portion 11c1 can be adjusted by the degree to which the roughened portion 11c of the first anode body 11a is compressed. Specifically, increasing the degree of compression of the roughened surface portion 11c of the first anode body 11a can reduce the porosity of the thin-walled portion 11c1, while decreasing the degree of compression of the roughened surface portion 11c of the first anode body 11a can increase the porosity of the thin-walled portion 11c1. In the first anode body 11a shown in FIG. 1A, each of the pair of roughened surface portions 11c has a thin-walled portion 11c1 that is thinner than each of the pair of roughened surface portions 11c of the second anode body 11b. Note that the thickness of the roughened surface portion 11c of the second anode body 11b refers to the thickness of an uncompressed portion that is not compressed in the thickness direction. Furthermore, the roughened surface portion 11c of the second anode body 11b and the uncompressed portion of the roughened surface portion 11c of the first anode body 11a typically have a porosity of 60% or more and 80% or less.

[0028] 1A illustrates an example in which the roughened surface portion 11c of the first anode body 11a includes a thin portion 11c1 compressed in the thickness direction and an uncompressed portion that is not compressed in the thickness direction. However, the configuration of the roughened surface portion 11c of the first anode body 11a is not limited to this. For example, the roughened surface portion 11c of the first anode body 11a may not include an uncompressed portion and may be configured only with the thin portion 11c1. That is, the entire roughened surface portion 11c of the first anode body 11a may be configured as the thin portion 11c1. Such a roughened surface portion 11c can be obtained by compressing the entire roughened surface portion 11c of the first anode body 11a in the thickness direction, or by compressing a portion of the roughened surface portion 11c of the first anode body 11a in the thickness direction to form the thin portion 11c1, and then removing the uncompressed portion by cutting. The removal of the uncompressed portion may be performed after forming the capacitor element 10 in a state where the roughened portion 11c of the first anode body portion 11a has an uncompressed portion, and then sealing the capacitor element 10 with a sealing resin, as described below.

[0029] 1A , separating member 15 is disposed in thin portion 11c1. By disposing separating member 15 in thin portion 11c1 in this manner, contact between first anode body 11a and cathode portion 14 is restricted. This makes it possible to suppress the occurrence of a short circuit between first anode body 11a and cathode portion 14.

[0030] As shown in FIG. 1A , the separating member 15 may be arranged to cover the entire exposed surface of the thin portion 11c1. Specifically, the separating member 15 may be arranged to cover the entire main surface (surface along the first direction D1) of the thin portion 11c1 and the entire side surface (surface along the height direction D2) of the thin portion 11c1. Note that the entire main surface of the thin portion 11c1 refers to a pair of opposing main surfaces of the thin portion 11c1. Furthermore, as will be described later, for example, when a solid electrolytic capacitor includes multiple capacitor elements 10 and these multiple capacitor elements 10 are stacked in the height direction so that their main surfaces overlap, each capacitor element 10 may include a separating member 15 on one of the main surfaces of the thin portion 11c1. For example, as shown in FIG. 1B , the capacitor element 10 may include a separating member 15 on a main surface below the thin portion 11c1 in the height direction D2. Furthermore, as shown in FIG. 1C, capacitor element 10 may include separating member 15 on the main surface above thin portion 11c1 in height direction D2.

[0031] The anode body 11 is formed using a metal containing a valve metal. For example, a foil (metal foil) containing a valve metal can be used for the anode body 11. Examples of valve metals include aluminum, tantalum, niobium, and titanium. The anode body 11 contains one or more valve metals. The anode body 11 may contain the valve metal in the form of an alloy or an intermetallic compound. The thickness of the anode body 11 is not particularly limited. The thickness of the anode body 11 other than the thin-walled portion 11c1, in other words, the thickness of the uncompressed portion of the anode body 11, may be, for example, 15 μm or more and 300 μm or less, or 80 μm or more and 250 μm or less.

[0032] As described above, the anode body 11 has the first anode body 11a and the second anode body 11b, and both the first anode body 11a and the second anode body 11b have a core portion 11d that is continuous with the roughened portion 11c in the thickness direction. In the anode body 11, the roughened portion 11c may be formed by an etching process such as electrolytic etching. That is, the roughened portion 11c may be an etched layer. The roughened portion 11c is a region having a plurality of fine pores. On the other hand, the core portion 11d is, for example, a region that has not been electrolytically etched.

[0033] The separating member 15 preferably has high insulating properties. The separating member 15 may be a conventionally known insulating tape (resist tape). For example, polyimide tape (PI tape) may be used as the insulating tape. The insulating tape has an adhesive layer. Therefore, when the separating member 15 is an insulating tape, the insulating region of the solid electrolytic capacitor described below may be formed by the end surface of the insulating tape.

[0034] The separating member 15 may be formed by adhering a resin composition containing a curable resin to at least a portion of the surface of the thin-walled portion 11c1. In other words, the separating member 15 may be a resin layer containing a curable resin. When the separating member 15 is a resin layer, the resin layer may have an adhesive layer on the end surface facing the first anode body 11a in the first direction D1. In this case, the insulating region of the solid electrolytic capacitor described below can be formed by the end surface of the resin layer facing the first anode body 11a in the first direction D1. The adhesive layer can be formed using various known adhesives. Examples of adhesives include acrylic adhesives, rubber adhesives, silicone adhesives, and urethane adhesives.

[0035] The curable resin may be a thermosetting resin or a photocurable resin. The photocurable resin may be a resin that is cured by visible light or ultraviolet light. Examples of curable resins include epoxy resins, polyimide resins, silicon resins, phenolic resins, urea resins, melamine resins, unsaturated polyester resins, furan resins, polyurethane resins, curable acrylic resins, and photoresist resins. The resin composition may contain a curing agent, a curing accelerator, a flame retardant, a filler, a coupling agent, a colorant, a mold release agent, and an inorganic ion scavenger, as necessary. Various known agents may be used. The resin composition may contain a thermoplastic resin (e.g., a polyamide resin, a polyamideimide resin, a polyolefin resin, a polyester resin, etc.) in addition to the curable resin.

[0036] As described above, the dielectric layer covers at least a portion of the anode body 11. The dielectric layer may be formed, for example, by anodizing the surface of the anode body 11 using a chemical conversion treatment or the like. Therefore, the dielectric layer may contain an oxide of the valve metal. For example, when aluminum is used as the valve metal, the dielectric layer may contain an oxide of Al ２ O ３ The dielectric layer may include a dielectric material. However, the dielectric layer is not limited to this and may be any material that functions as a dielectric. The dielectric layer is preferably formed on at least a portion of the surface of the roughened portion 11c of the first anode body 11a and the roughened portion 11c of the second anode body 11b. The dielectric layer is preferably formed on the outer surface of the roughened portion 11c in the first anode body 11a and the second anode body 11b, and more preferably formed along the inner wall surfaces of a plurality of fine holes in the roughened portion 11c in addition to the outer surface of the roughened portion 11c.

[0037] As described above, the solid electrolyte layer 12 covers at least a portion of the dielectric layer. The solid electrolyte layer 12 is also disposed on the second anode body 11b. That is, the solid electrolyte layer 12 covers at least a portion of the dielectric layer in the second anode body 11b. The solid electrolyte layer 12 may cover the entire surface of the dielectric layer in the second anode body 11b.

[0038] The solid electrolyte layer 12 preferably contains a conductive polymer. Examples of conductive polymers include polypyrrole, polythiophene, polyfuran, polyaniline, polyacetylene, polyphenylene, polyphenylvinylene, polyacene, and polythiophenevinylene. These may be used alone or in combination of two or more. The conductive polymer may also be a copolymer of two or more monomers.

[0039] In this specification, polypyrrole, polythiophene, polyfuran, polyaniline, etc. refer to polymers having polypyrrole, polythiophene, polyfuran, polyaniline, etc. as their basic skeletons, respectively. Therefore, polypyrrole, polythiophene, polyfuran, polyaniline, etc. may also include their respective derivatives. For example, polythiophene includes poly(3,4-ethylenedioxythiophene).

[0040] The conductive polymer may be included in the solid electrolyte layer 12 together with a dopant. The dopant may be a monomolecular anion or a polymeric anion. Examples of monomolecular anions include paratoluenesulfonic acid and naphthalenesulfonic acid. Examples of polymeric anions include polyvinylsulfonic acid, polystyrenesulfonic acid, polyallylsulfonic acid, polyacrylicsulfonic acid, polymethacrylicsulfonic acid, poly(2-acrylamido-2-methylpropanesulfonic acid), polyisoprenesulfonic acid, and polyacrylic acid. The above dopants may be used alone or in combination of two or more. Furthermore, the polymeric anion may be a polymer of a single monomer or a copolymer of two or more monomers.

[0041] The solid electrolyte layer 12 may contain known additives and known conductive materials other than conductive polymers, as needed. Examples of the conductive materials include at least one selected from the group consisting of conductive inorganic materials such as manganese dioxide and TCNQ (tetracyanoxydimethane) complex salts.

[0042] The conductive polymer can be obtained by chemical oxidative polymerization or electrolytic polymerization of a monomer (hereinafter simply referred to as a monomer) that constitutes the conductive polymer.

[0043] Chemical oxidative polymerization can be carried out by chemically oxidizing a monomer using a solvent, an oxidizing agent, a monomer, and, if necessary, a dopant. Examples of solvents that can be used include water, sulfuric acid, methanol, ethanol, propanol, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, chloroform, dichloromethane, carbon tetrachloride, benzene, toluene, xylene, tetrahydrofuran, N-methyl-2-pyrrolidone, and propylene carbonate. The monomer and dopant may be appropriately selected depending on the desired conductive polymer. Examples of oxidizing agents that can be used include ferric oxide, iron(III) tri(p-toluenesulfonate), sodium persulfate, potassium persulfate, ammonium persulfate, hydrogen peroxide, and potassium permanganate. The polymerization conditions for chemical oxidative polymerization can be appropriately selected depending on the types of solvent, oxidizing agent, monomer, and, if necessary, dopant used.

[0044] In electropolymerization, a monomer is polymerized in a solvent to obtain a conductive polymer. In electropolymerization, a dopant may be used as needed. As the solvent, those exemplified above can be used. The monomer and dopant may be appropriately selected depending on the desired conductive polymer.

[0045] Examples of electrolytic polymerization include a method in which a monomer and, if necessary, a dopant are dissolved in a solvent (hereinafter referred to as a monomer-containing solvent) by applying a potential sweep method or a constant voltage method using a potentiostat to polymerize the monomer, and a method in which a constant current method is applied to a monomer-containing solvent by using a galvanostat to polymerize the monomer. The dopant functions as an electrolyte in the monomer-containing solvent. The conditions for the potential sweep method, constant voltage method, and constant current method can be appropriately selected depending on the type of solvent, monomer, and, if necessary, dopant used.

[0046] As described above, the cathode extraction layer 13 covers at least a portion of the solid electrolyte layer 12. The cathode extraction layer 13 may cover the entire surface of the solid electrolyte layer 12. The cathode extraction layer 13 may include, for example, a carbon layer and a metal (e.g., silver) paste layer formed on the surface of the carbon layer. The configuration of the cathode extraction layer 13 is not limited thereto, and may be any configuration that has a current collecting function. Note that when the cathode extraction layer 13 includes a carbon layer and a metal paste layer, the carbon layer is laminated on the solid electrolyte layer 12.

[0047] The carbon layer contains a carbon material and has electrical conductivity. The carbon material is not particularly limited, and examples of the carbon material include graphite, carbon black, graphene flakes, and carbon nanotubes.

[0048] The carbon layer may contain at least one of a binder resin and an additive, as needed. The binder resin is not particularly limited, and known binder resins used in the manufacture of capacitor elements can be used. Examples of binder resins include thermosetting resins and thermoplastic resins. Examples of thermosetting resins include epoxy resins, polyimide resins, silicone resins, phenolic resins, urea resins, melamine resins, unsaturated polyester resins, and curable acrylic resins. Examples of thermoplastic resins include polyamide resins, polyamideimide resins, polyolefin resins, and polyester resins. Examples of additives include dispersants, surfactants, antioxidants, preservatives, bases, and acids.

[0049] The metal paste layer contains a metal material. The metal material is not particularly limited. From the viewpoint of enhancing electrical conductivity, the metal material preferably contains silver.

[0050] The volume ratio of the metal material in the metal paste layer is not particularly limited as long as it exceeds 0% by volume. From the viewpoint of reducing electrical resistance, the volume ratio of the metal material is preferably 60% by volume or more, more preferably 70% by volume or more, and even more preferably 80% by volume or more.

[0051] The metal paste layer may further contain a binder resin. The volume ratio of the binder resin in the metal paste layer is not particularly limited. From the viewpoint of reducing electrical resistance, the volume ratio of the binder resin is preferably 60% by volume or less, more preferably 20% by volume or less, and even more preferably 10% by volume or less. The volume ratio of the binder resin may be 0.1% by volume or more, or may be 0% by volume. The volume ratio of the binder resin can be confirmed, for example, by energy dispersive X-ray spectroscopy (SEM-EDX).

[0052] The thickness of the metal paste layer is not particularly limited. For example, the thickness of the metal paste layer may be 0.1 μm or more and 50 μm or less, or 1 μm or more and 20 μm or less. The thickness of the metal paste layer is the average value of five arbitrary points on a cross section in the thickness direction.

[0053] Next, a solid electrolytic capacitor according to an embodiment of the present disclosure will be described with reference to Figures 2A to 2C. Note that the cathode portion 14 is not shown in Figure 2A, and the anchor member 30 is not shown in Figures 2B and 2C. A solid electrolytic capacitor according to an embodiment of the present disclosure may include at least one of the above-described capacitor elements. However, a solid electrolytic capacitor according to an embodiment of the present disclosure may include multiple of the above-described capacitor elements. Below, an example in which a solid electrolytic capacitor includes multiple capacitor elements will be described.

[0054] 2A , in the solid electrolytic capacitor 100, the plurality of capacitor elements 10 are stacked in the height direction D2 with their main surfaces overlapping each other. Also, as shown in FIG. 2A , in the solid electrolytic capacitor 100, the plurality of capacitor elements 10 are stacked in the first direction D1 such that the end faces of the anode bodies 11 and the end faces of the cathode portions face the same direction. More specifically, the plurality of capacitor elements 10 are stacked such that the protruding end faces S1 of the first anode body portions 11 a of the anode bodies 11 face the same direction, and the terminal end faces S2 of the cathode portions face the same direction. Also, as will be described later, in the solid electrolytic capacitor 100, the plurality of capacitor elements 10 are entirely covered by an exterior body 120. In other words, the solid electrolytic capacitor 100 has an element stack 10A in which a plurality of capacitor elements 10 are stacked, and the outer casing 120 seals the element stack 10A. In the element stack 10A, each of the protruding end faces S1 of the first anode body portion 11a in the anode body 11 faces a first end face E1 (first surface) on one side of the outer casing 120, and each of the terminal faces S2 of the cathode portion faces a second end face E2 (second surface) on the other side of the outer casing 120.

[0055] There is no particular limitation on the number of stacked capacitor elements 10. The number of stacked capacitor elements 10 is, for example, 2 or more and 20 or less. Note that Fig. 2A shows an example in which four capacitor elements 10 are stacked.

[0056] A solid electrolytic capacitor 100 according to one embodiment of the present disclosure comprises a lead frame 110 electrically connected to each of the cathode portions of a plurality of capacitor elements 10, an outer casing 120 that seals the plurality of capacitor elements 10 and the lead frame 110, a first external electrode 130 electrically connected to each of the first anode body portions 11a of the plurality of capacitor elements 10 at a first end face E1 on one side of the outer casing 120 in the first direction D1, and a second external electrode 140 electrically connected to the lead frame 110 at a second end face E2 on the other side of the outer casing 120 in the first direction D1.

[0057] In the solid electrolytic capacitor 100 according to the embodiment of the present disclosure, in the plurality of capacitor elements 10, the protruding end surface S1 of each of the first anode body portions 11a is exposed from the first end surface E1 of the exterior body 120. In addition, in the plurality of capacitor elements 10, the end surface S2 of each of the cathode portions is disposed on the second end surface E2 side of the exterior body 120.

[0058] In the solid electrolytic capacitor 100 according to an embodiment of the present disclosure, in the plurality of capacitor elements 10, the roughened portion 11 c of each first anode body portion 11 a has only a thin portion 11 c 1. In the solid electrolytic capacitor 100 according to an embodiment of the present disclosure, the separating member 15 is disposed on the main surface below each thin portion 11 c 1 in the height direction D2. However, as described above, the separating member 15 may be disposed on the main surface above each thin portion 11 c 1 in the height direction D2 (see FIG. 1C ), or may be disposed on the main surfaces both above and below each thin portion 11 c 1 in the height direction D2 (see FIG. 1A ).

[0059] In a solid electrolytic capacitor 100 according to an embodiment of the present disclosure, in a plurality of capacitor elements 10, each separating member 15 is flush with the respective protruding end faces S1 of the first anode bodies 11a and has an end face Es exposed from the first end face E1 of the outer casing 120. That is, as shown in FIGS. 2A and 2B , the respective protruding end faces S1 of the first anode bodies 11a form a conductive region R1, and the respective end faces Es of the separating members 15 form an insulating region R2. As shown in FIG. 2B , the conductive region R1 preferably has a rectangular shape, and the insulating region R2 is preferably disposed on at least one main surface of the rectangular conductive region R1. The separating member 15 is preferably made of insulating tape (resist tape).

[0060] When the length of the conductive region R1 in the direction along the main surface is L1 and the length of the insulating region R2 in the direction along the main surface (the main surface of the conductive region R1) is L2, it is preferable that L1 and L2 satisfy the relationship L1≦L2, so that the insulating region R2 has a dimension sufficient to form the anchor member 30.

[0061] The insulating region R2 is preferably disposed outside at least one of the planes (in FIG. 2B , the plane in the height direction D2) perpendicular to the main surface of the conductive region R1. In other words, the insulating region R2 is preferably disposed so as to extend outward from the conductive region R1 on the first end surface E1 of the exterior body 120. Note that in FIG. 2B , the insulating region R2 is disposed outside both of the planes perpendicular to the main surface of the conductive region R1. By disposing the insulating region R2 in this manner, the region in which the anchor member is formed can be made sufficiently large.

[0062] In the solid electrolytic capacitor 100 according to an embodiment of the present disclosure, a conductive coating may be formed on the tip end surface S1 of the first anode body 11a, which constitutes the conductive region R1, by cold spraying or by AD. This conductive coating functions as an internal electrode of the solid electrolytic capacitor 100. Furthermore, by forming this conductive coating, natural oxidation of the tip end surface S1 of the first anode body 11a can be suppressed. Furthermore, the conductive coating has an uneven surface, which allows it to function as an anchor member in the conductive region R1. Conductive particles such as copper (Cu), aluminum (Al), titanium (Ti), silver (Ag), nickel (Ni), zinc (Zn), tin (Sn), molybdenum (Mo), iron (Fe), tantalum (Ta), niobium (Nb), silicon (Si), and chromium (Cr) can be used for the cold spraying or AD.

[0063] In the solid electrolytic capacitor 100 according to an embodiment of the present disclosure, an anchor member 30 is formed in the insulating region R2. In other words, at least a portion of the insulating region R2 is covered with the anchor member 30. The anchor member 30 can be formed, for example, by spraying insulating particles or conductive particles onto the insulating region R2. In the solid electrolytic capacitor 100 according to an embodiment of the present disclosure, the anchor member 30 is preferably also formed on the end surface (first end surface E1) of the exterior body 120 that includes the insulating region R2. In the solid electrolytic capacitor 100 according to an embodiment of the present disclosure, the anchor member 30 is preferably also formed on the end surface (second end surface E2) of the exterior body 120 that does not include the insulating region R2. The anchor member 30 can also be formed on the first end surface E1 and the second end surface E2 of the exterior body 120 by spraying insulating or conductive particles.

[0064] The insulating particles can be sprayed onto the insulating region R2 by shot blasting. Examples of shot blasting include sand blasting and wet blasting. As described above, the conductive particles can be sprayed onto the insulating region R2 by cold spraying, AD, or the like. In the solid electrolytic capacitor 100 according to an embodiment of the present disclosure, the anchor member 30 is preferably formed of insulating particles. In other words, the anchor member 30 is preferably made of an insulating material.

[0065] As described below, the exterior body 120 is typically configured as a resin exterior body. That is, the exterior body 120 typically has poor malleability. On the other hand, conductive particles such as copper (Cu) have excellent malleability. Therefore, when the conductive particles are sprayed onto the first end face E1 and the second end face E2 of the exterior body 120, it is difficult to form the anchor member 30 with the conductive particles sufficiently embedded in the exterior body 120. However, insulating particles such as silica, like the resin used to form the resin exterior body, have poor malleability. Therefore, when the insulating particles are sprayed onto the first end face E1 and the second end face E2 of the exterior body 120, it is possible to form the anchor member 30 with the insulating particles sufficiently embedded in the exterior body 120. That is, when the anchor members 30 are formed of insulating particles, it is possible to prevent the anchor members 30 from being formed sparsely on the first end face E1 and the second end face E2 of the exterior body 120, thereby preventing peeling between the exterior body 120 and the first external electrode 130 and also preventing peeling between the exterior body 120 and the second external electrode 140. Note that Fig. 2A shows an example in which the anchor members 30 are formed of insulating particles. Therefore, a sufficient amount of anchor members 30 is formed on the first end face E1 and the second end face E2 of the exterior body 120.

[0066] In the solid electrolytic capacitor 100 according to an embodiment of the present disclosure, as described above, the insulating region R2 having an adhesive layer is disposed on the first end surface E1 of the exterior body 120. Therefore, even when the anchor members 30 are formed of conductive particles, it is possible to prevent the anchor members 30 from being formed sparsely at least in the insulating region R2. This makes it possible to prevent peeling between the exterior body 120 and the first external electrode 130 compared to when the end surface of the exterior body 120 does not have the insulating region R2 having an adhesive layer.

[0067] The anchor member 30 may be formed by combining conductive particles and insulating particles. In this case, it is preferable that the occupancy ratio of the insulating particles is higher than the occupancy ratio of the conductive particles in the insulating region R2. This makes it possible to suppress excessive current flow in the insulating region R2. Furthermore, when the anchor member 30 is formed by combining conductive particles and insulating particles, it is preferable to spray the conductive particles after spraying the insulating particles in the insulating region R2.

[0068] Examples of insulating particles that can be used include silicon dioxide (silica), aluminum oxide (alumina), zirconium oxide (zirconia), titanium oxide (titania), and magnesium oxide (magnesia). Examples of conductive particles that can be used include those exemplified above.

[0069] The conductive particles and insulating particles for forming the anchor member 30 may have an average particle diameter of 5 μm or more, 10 μm or more, 30 μm or more, or 50 μm or more. The conductive particles and insulating particles may have an average particle diameter of 100 μm or less, or 90 μm or less. The average particle diameters of the conductive particles and insulating particles can be measured by centrifugal sedimentation or laser diffraction. Measurement of the average particle diameter by centrifugal sedimentation can be performed using an ultracentrifugal sedimentation particle size distribution analyzer manufactured by Beckman Costar. The average particle diameter determined by laser diffraction is the median diameter at which the volume-integrated value reaches 50% in volume-based particle size distribution measurement.

[0070] The conductive particles and insulating particles for forming the anchor member 30 may have a Vickers hardness of 80 Hv or more, 200 Hv or more, 500 Hv or more, or 1000 Hv or more. The upper limit of the Vickers hardness of the conductive particles and insulating particles may be, for example, 1200 Hv. The Vickers hardness of the conductive particles and insulating particles can be calculated, for example, by preparing a sample by embedding the conductive particles and insulating particles in a resin and polishing it, and using the test force and indentation depth when applying pressure with a triangular pyramidal indenter.

[0071] In the solid electrolytic capacitor 100 according to an embodiment of the present disclosure, when anchor members 30 are formed on the end face Es (insulating region R2) of the separating member 15 using conductive particles, it is preferable to simultaneously spray the conductive particles onto both the end face S1 of the first anode body 11a and the end face Es of the separating member 15 by cold spraying, AD, or the like. The conductive particles sprayed onto the end face S1 of the first anode body 11a (hereinafter also referred to as first conductive particles) and the conductive particles sprayed onto the end face Es of the separating member 15 (hereinafter also referred to as second conductive particles) may be the same or different types. Note that, when anchor members 30 are also formed on the first end face E1 of the outer casing 120, it is preferable to simultaneously spray the conductive particles onto the end face S1 of the first anode body 11a, the end face Es of the separating member 15, and the first end face E1 of the outer casing 120.

[0072] When the first conductive particles and the second conductive particles are different types, the cold spray treatment or AD method may be performed using mixed particles of the first conductive particles and the second conductive particles. Here, since the area of ​​the tip surface S1 of the first anode body 11a is typically larger than the area of ​​the end surface Es of the separating member 15, it is preferable that the content ratio of the first conductive particles in the mixed particles is higher than the content ratio of the second conductive particles. In the mixed particles, the content ratio of the first conductive particles is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more. In the mixed particles, the upper limit of the first conductive particles is, for example, 95% by mass. In the mixed particles, the content ratio of the second conductive particles is preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less. In the mixed particles, the lower limit of the second conductive particles is, for example, 5% by mass.

[0073] In solid electrolytic capacitor 100 according to an embodiment of the present disclosure, when an anchor member is formed on end surface Es of separating member 15 using insulating particles, the step of forming the anchor member on end surface Es of separating member 15 by shot blasting (hereinafter also referred to as step 1) and the step of forming a coating on end surface S1 of first anode body portion 11a by cold spray treatment or AD method (hereinafter also referred to as step 2) can be performed in any order.

[0074] Here, although the metal material (e.g., Al) constituting the first anode body 11a has excellent malleability, insulating particles are often less malleable than metal materials. That is, metal materials and insulating particles have opposing malleability characteristics. Therefore, when insulating particles are sprayed onto the tip surface S1 of the first anode body 11a, due to the difference in malleability, the insulating particles polish the tip surface S1 of the first anode body 11a without adhering to the tip surface S1 of the first anode body 11a. Therefore, by performing the first step first, the tip surface S1 of the first anode body 11a can be sufficiently polished with the insulating particles, and then a coating of conductive particles can be formed on the tip surface S1 in the second step.

[0075] In the solid electrolytic capacitor 100 according to an embodiment of the present disclosure, the anchor member 30 preferably covers 10% or more of the first end face E1 of the exterior body 120. In other words, the anchor member 30 preferably covers 10% or more of the surface of the exterior body 120 where the protruding end face S1 of the first anode body portion 11a and the end face Es of the separating member 15 are exposed. The anchor member 30 more preferably covers 20% or more of the first end face E1 of the exterior body 120, more preferably covers 30% or more, and even more preferably covers 40% or more. The upper limit of the coverage of the first end face E1 of the exterior body 120 by the anchor member 30 may be, for example, 60%. The coverage of the first end face E1 of the exterior body 120 by the anchor member 30 refers to the ratio (percentage) of the area of ​​the region where the anchor member 30 is formed to the value obtained by subtracting the area of ​​the conductive region from the total area of ​​the first end face E1 of the exterior body 120.

[0076] The exterior body 120 protects the plurality of capacitor elements 10 from impact, moisture, and the like. The exterior body 120 is configured to cover the entire plurality of capacitor elements 10. The exterior body 120 may have a rectangular parallelepiped shape as shown in FIGS. 2A to 2C. The exterior body 120 may be a resin exterior body or may be another exterior body. The exterior body 120 is preferably a resin exterior body. For example, an epoxy resin can be used as the material of the resin exterior body.

[0077] When the exterior body 120 is a resin exterior body, an inorganic filler may be contained in the exterior body 120. This can increase the strength of the exterior body 120. Examples of the inorganic filler include the insulating particles described above.

[0078] The average particle size of the inorganic filler is, for example, 60 μm or more and 80 μm or less. The average particle size of the inorganic filler can be determined in the same manner as the average particle sizes of the conductive particles and the insulating particles.

[0079] The first external electrode 130 and the second external electrode 140 can be obtained by applying a conductive paste containing conductive particles (e.g., silver particles) to the first end face E1 and the second end face E2 of the exterior body 120, drying the paste to form a conductive paste layer, and then plating a metal (e.g., nickel) on the conductive paste layer to form a metal plating layer. In the solid electrolytic capacitor 100, the first external electrode 130 is configured to cover the first end face E1 of the exterior body 120, and the second external electrode 140 is configured to cover the second end face E2 of the exterior body 120.

[0080] In the solid electrolytic capacitor 100 according to an embodiment of the present disclosure, the lead frame 110 has a sidewall portion 111 extending along the second end face E2 of the exterior package 120 and facing the terminal end face S2 of the cathode portion 14 in the first direction D1. The lead frame 110 also has a protruding portion 112 that intersects the sidewall portion 111 and extends toward the second end face E2 of the exterior package 120 and is exposed at the second end face E2. The lead frame 110 is electrically connected to the second external electrode 140 via the protruding portion 112. In other words, at the second end face E2 of the exterior package 120, the protruding end face S3 of the protruding portion 112 of the lead frame 110 is exposed and electrically connected to the second external electrode 140.

[0081] The side wall portion 111 of the lead frame 110 and the plurality of capacitor elements 10 are connected by a first conductive paste layer (not shown). This allows for electrical connection between each of the cathode portions of the plurality of capacitor elements 10 and the side wall portion 111 of the lead frame 110. More specifically, the side wall portion 111 of the lead frame 110 can be electrically connected to each of the end surfaces S2 of the cathode portions of the plurality of capacitor elements 10. The second end surface E2 of the exterior body 120 and the second external electrode 140 are also connected by a second conductive paste layer. This allows for electrical connection between the second external electrode 140 and the protruding portion 112 of the lead frame 110. The first conductive paste layer and the second conductive paste layer can be formed using various known conductive adhesives.

[0082] In solid electrolytic capacitor 100 according to an embodiment of the present disclosure, lead frame 110 includes a pair of projections 112 spaced apart from each other, as shown in FIG. 2C , and side wall 111 extends from between the pair of projections 112 along second end face E2 of exterior body 120 toward end face S2 of the cathode section. When solid electrolytic capacitor 100 is configured as described above, the contact area between second external electrode 140 and lead frame 110 can be increased, thereby enabling more optimal electrical connection between lead frame 110 and second external electrode 140.

[0083] In solid electrolytic capacitor 100 according to an embodiment of the present disclosure, lead frame 110 further includes bottom plate portion 113 that extends in first direction D1 along the lower end surface of the cathode portion and is connected to side wall portion 111 and protruding portion 112. When lead frame 110 is configured as described above, bottom plate portion 113 can adequately support multiple capacitor elements 10 from below. In FIG. 2A , the boundary between protruding portion 112 and bottom plate portion 113 is indicated by reference numeral B1.

[0084] In solid electrolytic capacitor 100 according to an embodiment of the present disclosure, bottom plate portion 113 of lead frame 110 is connected to the lower end surface of the cathode portion of capacitor element 10 by a fourth conductive paste layer (not shown). With this configuration, the lower end surface of capacitor element 10 can also be electrically connected to lead frame 110. That is, bottom plate portion 113 of lead frame 110 can be electrically connected so as to contact the lower end surface of the cathode portion.

[0085] In the solid electrolytic capacitor 100 according to an embodiment of the present disclosure, the length L of the protruding portion 112 in the lead frame 110 may be, for example, 0.60 mm or less, or 0.40 mm or less. The lower limit of the length L of the protruding portion 112 is typically 0.15 mm. In the lead frame 110, the thickness of the side wall portion 111 and the protruding portion 112 may be, for example, 0.08 mm or more and 0.30 mm or less.

[0086] Next, a method for manufacturing a solid electrolytic capacitor according to an embodiment of the present disclosure will be described.

[0087] A method for manufacturing a solid electrolytic capacitor according to an embodiment of the present disclosure includes a first step of preparing an anode body having a roughened portion extending from at least one outer surface toward a center in a thickness direction and a core portion continuous with the roughened portion in the thickness direction; a second step of forming a dielectric layer so as to cover at least a portion of the anode body; a third step of compressing a portion of the anode body having the roughened portion in the thickness direction to form a thin portion and arranging a separation member in this thin portion; a fourth step of covering at least a portion of the dielectric layer so as to expose the thin portion and the insulating member to form a cathode portion, thereby obtaining a laminate in which the anode body, the dielectric layer, and the cathode portion are laminated in this order; and a fourth step of forming a lead frame having a sidewall portion and an overhang portion extending in a direction intersecting the sidewall portion. a fifth step of arranging the laminate on the frame with the side wall portion of the lead frame electrically connected to the end face of the cathode portion, and sealing the lead frame and the laminate to obtain a sealed body; a sixth step of exposing the protruding end face of the anode body and the end face of the separating member from the first end face of the sealed body, and exposing the protruding end face of the protruding portion of the lead frame from the second end face of the sealed body; a seventh step of forming a conductive coating on the protruding end face of the anode body and forming an anchor member on the end face of the separating member; and an eighth step of arranging a first external electrode so as to be electrically connected to the protruding end face of the anode body exposed from the first end face of the sealed body, and arranging a second external electrode so as to be electrically connected to the protruding portion of the lead frame exposed from the second end face of the sealed body.

[0088] In the first step, the roughened portion can be formed by performing an etching process or the like on at least one outer surface of the anode body. The outer surface of the anode body refers to the main surface of the anode body. In the first step, it is preferable to perform an etching process or the like on each of the outer surfaces of the anode body, thereby forming a roughened portion on the anode body from each of the outer surfaces toward the center in the thickness direction. In the anode body, the region not subjected to the etching process or the like may be a core portion. The etching process may also be electrolytic etching.

[0089] In the second step, the dielectric layer can be formed by various known methods. The dielectric layer can be formed by oxidizing the valve metal contained in the anode body through chemical conversion treatment or the like. For example, the dielectric layer may be formed by immersing the anode body in a chemical conversion solution and applying a voltage. In the method for manufacturing a solid electrolytic capacitor according to an embodiment of the present disclosure, as described above, the anode body has a roughened portion. Therefore, the dielectric layer may be formed on the outer surface of the roughened portion or along the inner wall surfaces of a plurality of fine holes in the roughened portion. The dielectric layer is typically formed over substantially the entire area of ​​the anode body. That is, the dielectric layer is typically formed on both the first anode body and the second anode body.

[0090] In the third step, the thin-walled portion is formed by compressing a part of the anode body having the roughened portion in the thickness direction. The pressure when compressing the part of the anode body in the thickness direction can be appropriately adjusted taking into consideration the porosity of the roughened portion before compression and the porosity of the desired thin-walled portion. In the second step, the anode body is divided into a first anode body part having a thin-walled portion and a second anode body part not having a thin-walled portion. The first anode body part is a region of the anode body that does not have a cathode part including a solid electrolyte layer, and the second anode body part is a region of the anode body that has a cathode part including a solid electrolyte layer.

[0091] In the fourth step, the cathode portion can be formed by various known methods. The solid electrolyte layer in the cathode portion can be formed, for example, by attaching a conductive polymer monomer (hereinafter simply referred to as "monomer") to at least a portion of the dielectric layer, and then chemically oxidizing or electrolytically polymerizing the monomer on at least a portion of the dielectric layer to form a conductive polymer layer. The attachment of the monomer to at least a portion of the dielectric layer can be performed by immersing at least a portion of the anode body on which the dielectric layer has been formed in a polymerization solution containing the monomer. In a method for manufacturing a solid electrolytic capacitor according to an embodiment of the present disclosure, the monomer is attached to the dielectric layer formed on the second anode body to form a conductive polymer layer on the second anode body. When electrolytically polymerizing the monomer, a voltage in the range of 1 to 5 V may be applied as electrical energy to the anode body.

[0092] The solid electrolyte layer in the cathode section may be formed by applying a treatment liquid containing a conductive polymer onto the dielectric layer to form a coating film, and then drying the coating film. The conductive polymer may be, for example, poly(3,4-ethylenedioxythiophene) (PEDOT). The dopant may be, for example, polystyrene sulfonic acid (PSS). The treatment liquid is a dispersion or solution of the conductive polymer. Examples of the dispersion medium (solvent) include water, an organic solvent, or a mixture thereof.

[0093] The cathode extraction layer in the cathode section can be obtained, for example, by applying a carbon dispersion liquid containing dispersed carbon so as to cover at least a portion of the solid electrolyte layer, drying the liquid to form a carbon layer, and then applying a composition containing metal particles (e.g., silver particles) and a resin component (binder resin) so as to cover at least a portion of the carbon layer, and then heating and drying the composition to form a conductive layer. Note that if the binder resin is a thermosetting resin, the binder resin can be thermally cured by the above-mentioned heating and drying. In this manner, a laminate in which the anode body, the dielectric layer, and the cathode section are stacked in this order can be obtained.

[0094] In the fifth step, a lead frame having sidewall portions and protruding portions extending in a direction intersecting the sidewall portions can be obtained by processing a metal plate into a predetermined shape. In addition to the sidewall portions and protruding portions, the lead frame preferably further includes a bottom plate portion connected to the sidewall portions and the protruding portions. By including the bottom plate portion in the lead frame, the laminate obtained as described above can be sufficiently supported from the lower surface side. The bottom plate portion preferably extends in the same direction as the extending direction of the protruding portions. In other words, the bottom plate portion preferably extends in a direction intersecting the sidewall portions.

[0095] The side wall portion of the lead frame and the end surface of the cathode portion can be electrically connected, for example, by interposing a conductive paste layer therebetween. The lead frame and the laminate are sealed, for example, by using a sealing resin or the like to embed the entire lead frame and the laminate. When the sealing resin is a thermosetting resin, it is preferable that the sealing resin be thermally cured after embedding the lead frame and the laminate. For sealing with the sealing resin, conventionally known techniques such as transfer molding or compression molding can be applied.

[0096] In a sixth step, the first end face and the second end face of the sealing body are cut to a predetermined size by, for example, blade dicing or using an ultrasonic cutter, so that the protruding end face of the anode body and the protruding end face of the protruding portion of the lead frame are exposed. Note that in the method for manufacturing a solid electrolytic capacitor according to an embodiment of the present disclosure, the protruding end face of the anode body refers to the protruding end face of the first anode body portion. Furthermore, the protruding end face of the anode body and the end face of the separating member are exposed from the first end face of the sealing body after cutting, and the protruding end face of the protruding portion of the lead frame is exposed from the second end face of the sealing body after cutting.

[0097] In the seventh step, a conductive coating is formed on the end surface of the anode body at the first end surface of the sealing body after cutting, and an anchor member is formed on the end surface of the separation member. The anchor member may be formed on the first end surface of the sealing body after cutting. The conductive coating can be formed by cold spray processing or AD method, as described above. When forming the anchor member on the end surface of the separation member using conductive particles, the conductive coating and anchor member may be formed by spraying the conductive particles onto the end surface of the anode body and the end surface of the separation member using cold spray processing or AD method, as described above. On the other hand, when forming the anchor member on the end surface of the separation member using insulating particles, a first substep of forming the anchor member on the end surface of the separation member by shot blasting and a second substep of forming a conductive coating on the end surface of the anode body using cold spray processing or AD method may be performed. The first and second substeps can be performed in any order, but it is preferable to perform the second substep after performing the first substep. The conductive particles and insulating particles may be the same as those exemplified above.

[0098] In the seventh step, a cold spray process or an AD process may be performed on the second end face of the sealing body after cutting to form a conductive coating on the protruding end face of the protruding portion of the lead frame. Furthermore, in the seventh step, at least one of conductive particles and insulating particles may be sprayed onto the resin portion of the first end face and the second end face of the sealing body after cutting to form anchor members in the resin portion as well.

[0099] In step eight, the first external electrode can be obtained by applying a conductive paste containing conductive particles (e.g., silver particles) to the first end surface of the cut sealing body to form a conductive paste layer, and then plating a metal (e.g., nickel) on the conductive paste layer to form a metal plating layer. Similarly, the second external electrode can be obtained by forming a conductive paste layer and a metal plating layer in this order on the second end surface of the cut sealing body. The first external electrode obtained as described above is electrically connected to the protruding end surface of the anode body (i.e., the protruding end surface of the first anode body portion), and the second external electrode obtained as described above is electrically connected to the protruding end surface of the protruding portion of the lead frame.

[0100] As described above, by performing the first to eighth steps, a solid electrolytic capacitor according to an embodiment of the present disclosure can be obtained.

[0101] Although the present specification has described an example in which solid electrolytic capacitor 100 includes a plurality of capacitor elements 10 as an embodiment, solid electrolytic capacitor 100 may include only one capacitor element 10 .

[0102] Furthermore, in this specification, an example has been described as one embodiment in which solid electrolytic capacitor 100 has an element stack 10A in which a plurality of capacitor elements 10 are stacked, an outer casing 120 seals element stack 10A, and in element stack 10A, each of the protruding end faces S1 of first anode body portion 11a in anode body 11 faces first end face E1 on one side of outer casing 120, and each of the terminal faces S2 of the cathode portion faces second end face E2 on the other side of outer casing 120; however, the configuration of solid electrolytic capacitor 100 is not limited to this. For example, in the solid electrolytic capacitor 100, a first capacitor element in which the end face S1 of the first anode body portion 11a in the anode body 11 faces the first end face E1 of the outer casing 120 and a second capacitor element in which the end face S1 of the first anode body portion 11a in the anode body 11 faces the second end face E2 of the outer casing 120 may be alternately stacked to form the element stack 10A.

[0103] Furthermore, in this specification, as one embodiment, an example has been described in which, in the element stack 10A, the protruding end faces S1 of the first anode body portions 11a in the anode body 11 each face the first end face E1 on one side of the outer casing 120, the terminal faces S2 of the cathode portions each face the second end face E2 on the other side of the outer casing 120, the protruding end faces S1 of the first anode body portions 11a each are exposed at the first end face E1 of the outer casing 120, and the protruding portions 112 of the lead frame 110 electrically connected to each of the cathode portions each are exposed at the second end face E2 of the outer casing 120; however, the configuration of the solid electrolytic capacitor 100 is not limited to this. For example, as described above, in the case where element stack 10A is configured such that each protruding end surface S1 of first anode body portion 11a in anode body 11 faces first end surface E1 of exterior body 120 and each terminal end surface S2 of each cathode portion faces second end surface E2 of exterior body 120, cathode foils may be interposed between the cathode portions, and each end surface of the cathode foil may be exposed at second end surface E2 of exterior body 120. Note that since the cathode foil is also a component of the cathode portion, the end surface of the cathode portion also includes the end surface of the cathode foil. The cathode foil may include separation member 15, similar to anode body 11. As a result, the end surface of the cathode foil includes both a conductive region R1 and an insulating region R2.

[0104] (Additional Notes) The above description discloses the following technologies. (Technology 1) A solid electrolytic capacitor comprising: a capacitor element having an anode portion and a cathode portion; an exterior housing sealing the capacitor element; a first external electrode electrically connected to the anode portion; and a second external electrode electrically connected to the cathode portion, wherein at least one of end faces of the anode portion and the cathode portion is exposed from the exterior housing and electrically connected to the first external electrode or the second external electrode, the end face exposed from the exterior housing has a conductive region and an insulating region, at least a portion of the insulating region has an adhesive layer, and at least a portion of the insulating region is covered with an anchor member. (Technology 2) The solid electrolytic capacitor according to Technology 1, wherein the conductive region has a rectangular shape, and the insulating region is located on at least one main surface of the conductive region. (Technology 3) The solid electrolytic capacitor according to Technology 2, wherein the insulating region is located outside at least one of surfaces perpendicular to the main surfaces. (Technology 4) The solid electrolytic capacitor according to Technology 2 or 3, wherein L1 is the length of the conductive region in a direction along the main surface, and L2 is the length of the insulating region in a direction along the main surface, and L1 and L2 satisfy the relationship L1≦L2. (Technology 5) The solid electrolytic capacitor according to any one of Technology 1 to 4, wherein the anchor member covers 10% or more of the surface of the exterior body where the end faces are exposed. (Technology 6) The solid electrolytic capacitor according to any one of Technology 1 to 5, further comprising an element stack in which a plurality of the capacitor elements are stacked, the exterior body sealing the element stack, and wherein, in the element stack, each of the end faces of the anode portions faces a first surface of the exterior body and each of the end faces of the cathode portions faces a second surface different from the first surface of the exterior body. (Technology 7) The solid electrolytic capacitor according to any one of Technology 1 to 6, wherein the anchor member is made of an insulating material.

[0105] While the present invention has been described in terms of a presently preferred embodiment, various modifications and variations are possible.

[0106] The solid electrolytic capacitor according to the present disclosure can be used in applications where it is necessary to prevent peeling between the exterior body and the external electrode.

[0107] 10: capacitor element, 10A: element stack, 11: anode body, 11a: first anode body portion, 11b: second anode body portion, 11c: roughened portion, 11c1: thin portion, 11d: core portion, 12: solid electrolyte layer, 13: cathode lead layer, 14: cathode portion, 15: separation member, 30: anchor member, 100: solid electrolytic capacitor, 111: side wall portion, 112: protruding portion, 113: bottom plate portion, 120: exterior body, 130: first external electrode, 140: second external electrode, D1: first direction, D2: height direction, E1: first end face, E2: second end face, R1: conductive region, R2: insulating region, S1: tip face, S2: terminal face, S3: tip face

Claims

1. A solid electrolytic capacitor comprising: a capacitor element having an anode portion and a cathode portion; an exterior housing sealing the capacitor element; a first external electrode electrically connected to the anode portion; and a second external electrode electrically connected to the cathode portion, wherein at least one of end faces of the anode portion and the cathode portion is exposed from the exterior housing and electrically connected to the first external electrode or the second external electrode, the end face exposed from the exterior housing has a conductive region and an insulating region, at least a portion of the insulating region has an adhesive layer, and at least a portion of the insulating region is covered with an anchor member.

2. The solid electrolytic capacitor according to claim 1, wherein the conductive region has a rectangular shape, and the insulating region is disposed on at least one main surface of the conductive region.

3. The solid electrolytic capacitor according to claim 2, wherein the insulating region is disposed outside at least one of the surfaces perpendicular to the main surface.

4. The solid electrolytic capacitor according to claim 2 or 3, wherein L1 is the length of the conductive region in the direction along the main surface, and L2 is the length of the insulating region in the direction along the main surface, and L1 and L2 satisfy the relationship L1≦L2.

5. The solid electrolytic capacitor according to claim 1 or 2, wherein the anchor member covers 10% or more of the surface of the exterior body where the end face is exposed.

6. The solid electrolytic capacitor according to claim 1 or 2, comprising an element stack in which a plurality of the capacitor elements are stacked, the exterior housing sealing the element stack, and in the element stack, each of the end faces of the anode portion faces a first surface of the exterior housing, and each of the end faces of the cathode portion faces a second surface different from the first surface of the exterior housing.

7. The solid electrolytic capacitor according to claim 1 or 2, wherein the anchor member is made of an insulating material.

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