Capacitor stacks, solid electrolytic capacitors

Abstract

This addresses reliability and characteristic issues arising from the electrical and physical connections of multiple capacitor elements, and suppresses ESR degradation during implementation. [Solution] The capacitor elements 12 used in the capacitor stack comprise an anode body 121 made of a film-like valve-acting metal, a dielectric layer 122 covering it, a conductive polymer layer 123, and a conductive layer 124. The conductive polymer layer extends in a direction perpendicular to the first direction DIR1 in the second region RE2 and has a first protrusion 1291 that projects toward the conductive layer. At least a portion of the first protrusions of adjacent capacitor elements in the stacking direction overlaps. Adjacent capacitor elements in the stacking are connected through their respective first protrusions. The outermost surface of the conductive layer is a silver layer 1242.

Description

TECHNICAL FIELD

[0001] The present invention relates to a solid electrolytic capacitor configured by stacking a plurality of capacitor elements.

BACKGROUND ART

[0002] Patent Document 1 describes a solid electrolytic capacitor. The solid electrolytic capacitor of Patent Document 1 includes a plurality of solid electrolytic capacitor elements.

[0003] Each of the plurality of solid electrolytic capacitor elements is in the form of a flat film, and includes a flat film-shaped anode portion and a cathode portion covering the anode portion. Here, the flat film shape refers to a solid shape having a predetermined thickness (for example, about 0.1 mm) and an area, and is also expressed as a flat plate shape or a foil shape. The plurality of solid electrolytic capacitor elements are stacked such that the respective cathode portions face each other and the flat film surfaces overlap with each other.

[0004] A silver (Ag)-containing conductive adhesive is disposed between the cathode portions of adjacent solid electrolytic capacitor elements, and the adjacent solid electrolytic capacitor elements are electrically and physically connected by the conductive adhesive.

PRIOR ART DOCUMENTS

PATENT DOCUMENTS

[0005]

PATENT DOCUMENT 1

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] However, in the conventional configuration as shown in Patent Document 1, since the electrical and physical connection between adjacent cathode portions (between capacitor elements) relies on the silver-containing conductive adhesive, problems of reliability and characteristics may occur.

[0007] Therefore, the object of the present invention is to suppress reliability and characteristic problems that arise in the electrical and physical connections of multiple capacitor elements without relying on silver-containing conductive adhesives. It is also to suppress ESR degradation during reflow mounting of the solid electrolytic capacitor. [Means for solving the problem]

[0008] A capacitor laminate according to one embodiment of this invention comprises a plurality of capacitor elements, each consisting of a flat film, which are stacked so that their respective flat film surfaces overlap.

[0009] The capacitor element comprises an anode body made of a film-like valve-acting metal, a dielectric layer covering the anode body, a conductive polymer layer covering the dielectric layer, and a conductive layer covering the conductive polymer layer. The conductive layer is formed in a predetermined area that includes the other end of the anode body but does not include one end in the first direction, and has a first end on the side of the one end and a second end on the side of the other end.

[0010] The conductive layer and the conductive polymer layer have a first region at the first end and a second region at the second end in the plane on which the conductive layer is formed. The conductive polymer layer has a first convex portion in the second region that extends in a direction perpendicular to the first direction and protrudes toward the conductive layer.

[0011] In a plurality of capacitor elements, the first protrusions of adjacent capacitor elements overlap at least partially when viewed in the stacking direction. Adjacent capacitor elements in a plurality of capacitor elements are connected through their respective first protrusions. The conductive layer has a silver layer on its outermost surface, and the silver layer is composed of layers containing silver powder and amorphous resin.

[0012] In this configuration, the first protrusions of adjacent capacitor elements come into contact with each other before the non-formed portion of the first protrusions of adjacent capacitor elements. When multiple capacitor elements are pressed in the stacking direction in this state, the first protrusions of adjacent capacitor elements are crushed. As a result, adjacent capacitor elements are securely connected by their respective first protrusions over a predetermined area. The connection is further stabilized by performing the pressurization under heating.

[0013] Therefore, adjacent capacitor elements in multiple capacitor elements are connected in a physically and electrically stable manner without the need for a separate conductive adhesive. [Effects of the Invention]

[0014] According to this invention, reliability and characteristic problems arising in the electrical and physical connections of multiple capacitor elements can be suppressed. [Brief explanation of the drawing]

[0015] [Figure 1] Figure 1 is a side cross-sectional view of a solid electrolytic capacitor according to the first embodiment. [Figure 2] Figure 2 is an external perspective view of a capacitor element according to the first embodiment. [Figure 3] Figure 3(A) is a first plan view of the capacitor element according to the first embodiment, Figure 3(B) is a side cross-sectional view, and Figure 3(C) is a second plan view. [Figure 4] Figure 4 is an enlarged cross-sectional view of the portion of the capacitor element including the protrusion according to the first embodiment. [Figure 5] Figures 5(A) and 5(B) are enlarged cross-sectional views showing the locations of the protrusions when multiple capacitor elements are stacked. [Figure 6] Figures 6(A), 6(B), 6(C), 6(D), and 6(E) are plan views showing the state of each manufacturing process of the capacitor element according to the first embodiment. [Figure 7] Figure 7(A) is a plan view of the capacitor element according to the second embodiment, and Figure 7(B) is a side cross-sectional view. [Figure 8] Figure 8(A) is a plan view of a capacitor element according to the third embodiment, and Figure 8(B) is a side cross-sectional view. [Figure 9] Figure 9 is a side cross-sectional view of a solid electrolytic capacitor according to the fourth embodiment. [Modes for carrying out the invention]

[0016] [First Embodiment] A solid electrolytic capacitor according to the first embodiment of the present invention will be described with reference to the drawings. In the present embodiment, an aluminum solid electrolytic capacitor is described as an example, but the configuration of the present embodiment can be applied to any capacitor that includes a plurality of capacitor elements each functioning individually as a capacitor in a single housing (insulating resin body).

[0017] FIG. 1 is a side cross-sectional view of the solid electrolytic capacitor according to the first embodiment. FIG. 2 is an external perspective view of the capacitor element according to the first embodiment. FIG. 3(A) is a first plan view of the capacitor element according to the first embodiment, FIG. 3(B) is a side cross-sectional view, and FIG. 3(C) is a second plan view. FIG. 4 is an enlarged cross-sectional view of a portion including a convex portion of the capacitor element according to the first embodiment.

[0018] (Overview of Solid Electrolytic Capacitor 1) As shown in FIG. 1, the solid electrolytic capacitor 1 includes a capacitor laminate 10, a first terminal electrode 20, a second terminal electrode 30, and an insulating resin body 40.

[0019] The capacitor laminate 10 includes a plurality of capacitor elements 11-14 (capacitor element 11, capacitor element 12, capacitor element 13, capacitor element 14). In the present embodiment, the number of capacitor elements constituting the capacitor laminate 10 is four, but the number of capacitor elements may be any plural number.

[0020] (Capacitor Elements 11-14) The plurality of capacitor elements 11-14 have the same configuration in terms of the structure that functions as a capacitor. Here, the configuration of the plurality of capacitor elements 11-14 will be described with the capacitor element 12 as a representative, with reference to FIG. 2, FIG. 3(A), FIG. 3(B), FIG. 3(C), and FIG. 4.

[0021] The capacitor element 12 includes an anode body 121, a dielectric layer 122, a conductive polymer layer 123, and a conductive layer 124.

[0022] The anode body 121 is a rectangular flat film when viewed from above. The anode body 121 has two main surfaces 121F1 and 121F2 that are parallel to a first direction DIR1 and a second direction DIR2, which are orthogonal to each other. One end of the anode body 121 in the first direction DIR1 is one end 121EL1, and the other end is the other end 121EL2. The area of ​​the anode body 121 is set based on the capacitance realized by the capacitor element 12.

[0023] The anode 121 is made of, for example, a single metal such as aluminum, tantalum, niobium, titanium, zirconium, magnesium, or silicon, or an alloy containing these metals. Preferably, the anode 121 is aluminum or an aluminum alloy. The anode 121 can be any valve-acting metal that exhibits so-called valve action.

[0024] Although detailed illustrations are omitted, the anode body 121 is composed of multiple layers in the thickness direction (DIRH direction). Specifically, the anode body 121 is composed of a core portion, a first surface portion, and a second surface portion. The first surface portion, the core portion, and the second surface portion are arranged in this order (first surface portion, core portion, second surface portion) from the main surface 121F1 to the main surface 121F2 of the anode body 121.

[0025] The core is not a porous material. The first surface layer and the second surface layer are porous materials. The thickness of the core is preferably 5 μm or more and 100 μm or less. The thickness of the first surface layer and the second surface layer are preferably 5 μm or more and 200 μm or less, respectively. Furthermore, the porous material is formed by interconnected cavities having a diameter (or the maximum dimension that determines the volume) of 0.5 μm or less, and the maximum dimension of the area portion opening to the main surface F1 and the main surface F2 is 0.5 μm or less.

[0026] The dielectric layer 122 covers the anode 121. More specifically, the dielectric layer 122 covers the main surfaces F1 and F2 of the anode 121. More precisely, the dielectric layer 122 covers the surface of the porous material constituting the first surface layer of the anode 121, and the surface of the porous material constituting the second surface layer. The dielectric layer 122 also covers both sides of the anode 121, as well as the end surface of the other end 121EL2.

[0027] The dielectric layer 122 is preferably made of an oxide film of the anode 121. When aluminum foil is used as the anode 121, the dielectric layer 122 is formed by oxidation in an aqueous solution containing boric acid, phosphoric acid, adipic acid, or their sodium salts, ammonium salts, etc. The thickness of the dielectric layer 122 is preferably 1 nm or more and 100 nm or less.

[0028] The conductive polymer layer 123 covers the outer surface of the dielectric layer 122 opposite to the surface in contact with the anode 121. The conductive polymer layer 123 has a first surface 123F1 on the main surface 121F1 side of the anode 121 as the surface of the conductive polymer layer 123. The conductive polymer layer 123 has a second surface 123F2 on the main surface 121F2 side of the anode 121 as the surface of the conductive polymer layer 123. The first surface 123F1 and the second surface 123F2 are substantially flat surfaces except for the part where the protrusion 129 (details will be described later) is formed.

[0029] The conductive polymer layer 123 does not cover one end 121EL1 of the anode body 121 in the first direction DIR1, but covers the other end 121EL2 of the anode body 121 in the first direction DIR1 via the dielectric layer 122.

[0030] The conductive polymer layer 123 may be made of a conductive polymer with a backbone such as pyrroles, thiophenes, or anilines, or a conductive polymer with a backbone such as PEDOT [poly(3,4-ethylenedioxythiophene)], and may be a PEDOT:PSS layer compounded with polystyrene sulfonic acid (PSS) as a dopant. The conductive polymer layer 123 is formed by a method of forming a polymerized film of poly(3,4-ethylenedioxythiophene) on the surface of the dielectric layer 122 using an electrolyte solution, for example, a treatment solution containing a monomer such as 3,4-ethylenedioxythiophene, or by a method of applying a dispersion of a polymer such as poly(3,4-ethylenedioxythiophene) to the surface of the dielectric part and drying it.

[0031] The conductive layer 124 has a two-layer structure consisting of a carbon layer 1241 and a silver layer 1242. The carbon layer 1241 is formed on the surface of the conductive polymer layer 123. The silver layer 1242 is formed on the surface of the carbon layer 1241.

[0032] The conductive layer 124 has a surface 124F1 on the side of the first surface 123F1 of the conductive polymer layer 123. The conductive layer 124 has a surface 124F2 on the side of the second surface 123F2 of the conductive polymer layer 123. Surfaces 124F1 and 124F2 are substantially flat surfaces except for the areas where the convex portions 129 (details of which will be described later) are formed in the conductive polymer layer 123.

[0033] The conductive layer 124 has a first end 124EL1 on one end 121EL1 side of the anode body 121 in the first direction DIR1, and a second end 124EL2 on the other end 121EL2 side.

[0034] The conductive layer 124 has a first side end 124ES1 at one end in the second direction DIR2 and a second side end 124ES2 at the other end.

[0035] The conductive layer 124 has a ridge portion 124CN1 where the second end 124EL2 and the first side end 124ES1 intersect, and a ridge portion 124CN2 where the second end 124EL2 and the second side end 124ES21 intersect.

[0036] The thickness of the conductive layer 124 is preferably, for example, 2 μm or more and 20 μm or less.

[0037] The silver layer 1242 constituting the conductive layer 124 preferably contains silver powder and a thermoplastic resin, and the thermoplastic resin is particularly preferably an amorphous resin. Examples of amorphous resins include polyvinyl acetal, polyvinyl butyral, phenoxy resin, polystyrene, polymethyl methacrylate, polyamide-imide, polycarbonate, polyethersulfone, polyetherimide, polyvinyl acetate, acrylonitrile butadiene styrene resin, acrylonitrile styrene resin, polysulfone, and polyethersulfone.

[0038] With this configuration, the capacitor element 12 functions as a solid electrolytic capacitor with the anode body 121 as the anode and the conductive polymer layer 123 and conductive layer 124 as the cathode.

[0039] The capacitor element 12 may further include an insulating mask layer of a predetermined width provided around the dielectric layer 122. In this case, the insulating mask layer is provided on both main surfaces and both sides of the anode body 121 so as to be parallel to the short side of the anode body 121. The insulating mask layer effectively separates the anode body 121 into anode and cathode. That is, the region where the conductive polymer layer 123 and conductive layer 124 (carbon layer 1241 and silver layer 1242) are not formed is the anode, and the region where the conductive polymer layer 123 and conductive layer 124 are formed is the cathode.

[0040] The conductive polymer layer 123 may be provided so as to cover at least a portion of the outer surface of the insulating mask layer, and the leading edge of the conductive polymer layer 123 on the insulating mask layer side may be provided so as not to overlap with the insulating mask layer. The insulating mask layer can also be provided in the capacitor elements of subsequent embodiments.

[0041] Furthermore, the capacitor element 12 includes a protrusion 129. The protrusion 129 is formed on the first surface 123F1 and the second surface 123F2 of the conductive polymer layer 123, respectively. The protrusion 129 is made of the same material as the conductive polymer layer 123.

[0042] As shown in Figure 4, the height H129 of the protrusion 129 is greater than the thickness D124 of the conductive layer 124. While the height H129 of the protrusion 129 may be less than or equal to the thickness D124 of the conductive layer 124, it is preferable that it be greater.

[0043] The protrusion 129 of the first surface 123F1 projects from the first surface 123F1 toward the conductive layer 124 that is in contact with the first surface 123F1. The protrusion 129 of the second surface 123F2 projects from the second surface 123F2 toward the conductive layer 124 that is in contact with the second surface 123F2.

[0044] The protrusions 129 on the first surface 123F1 and the protrusions 129 on the second surface 123F2 have the same shape when viewed from above, and therefore overlap.

[0045] More specifically, in a plan view of the capacitor element 12, the protrusion 129 is composed of a rod-shaped first protrusion 1291 extending along the second direction DIR2 and two rod-shaped second protrusions 1292 extending along the first direction DIR1.

[0046] The first protrusion 1291 is formed near the second end 124EL2 of the conductive layer 124 in the first direction DIR1, and has a shape that extends parallel to the direction in which the second end 124EL2 extends. One end of the first protrusion 1291 in the direction of extension is located near the first side end 124ES1, and the other end is located near the second side end 124ES2. In other words, the first protrusion 1291 is formed on the conductive polymer layer 123 with a shape that extends over substantially the entire length of the conductive layer 124 and the conductive polymer layer 123 in the second direction DIR2.

[0047] One of the second protrusions 1292 is formed near the first side end 124ES1 of the conductive layer 124 in the second direction DIR2, and has a shape that extends parallel to the direction in which the first side end 124ES1 extends. One end of the second protrusion 1292 in the direction of extension connects to the end of the first protrusion 1291 on the side of the first side end 124ES1. The other end of the second protrusion 1292 in the direction of extension is located on the side of the second end 124EL2 than the center of the first direction DIR1 of the conductive layer 124 and the conductive polymer layer 123. In other words, the other end of the second protrusion 1292 in the direction of extension is not located on the first end 124EL1 side of the center of the first direction DIR1 of the conductive layer 124 and the conductive polymer layer 123.

[0048] The other second protrusion 1292 is formed near the second side end 124ES2 of the conductive layer 124 in the second direction DIR2 and has a shape that extends parallel to the direction in which the second side end 124ES2 extends. One end of the other second protrusion 1292 in the direction of extension connects to the end of the first protrusion 1291 on the side of the second side end 124ES2. The other second protrusion 1292 has a shape that extends from the connection end to the second side end 124ES2 toward the first end 124EL1 of the conductive layer 124. The other end of the other second protrusion 1292 in the direction of extension is located toward the second end 124EL2 than the center of the first direction DIR1 of the conductive layer 124 and the conductive polymer layer 123. In other words, the other end of the second protrusion 1292 in the direction in which it extends is not located on the first end 124EL1 side of the center of the first direction DIR1 of the conductive layer 124 and the conductive polymer layer 123.

[0049] Thus, the protrusion 129 has a shape in which a first protrusion 1291 extending along the second direction DIR2 and two second protrusions 1292 extending along the first direction DIR1 are connected. In other words, the protrusion 129 has a shape that bends at approximately right angles at two points in the direction in which it extends as a whole. And, having these bends, the protrusion 129 has a shape that extends along the edge 124CN1 (the first corner when the conductive layer 124 is viewed from above) and the edge 124CN2 (the second corner when the conductive layer 124 is viewed from above).

[0050] Then, a reference line Fs parallel to the second direction DIR2 is set midway between the first end 124EL1 and the second end 124EL2 with respect to the plane of the conductive layer 124 (surfaces 124F1, 124F2). As a result, the plane of the conductive layer 124 (surfaces 124F1, 124F2) is divided into a first region RE1 at the first end 124EL1 relative to the reference line Fs, and a second region RE2 at the second end 124EL2 relative to the reference line Fs.

[0051] Thus, the protrusion 129 is formed in the second region RE2. While a portion of the second protrusion 1292 of the protrusion 129 may reach the first region RE1, it is preferable that substantially the entire protrusion 129 is formed in the second region RE2.

[0052] (Specific configuration of the capacitor stack 10 and the solid electrolytic capacitor 1) As described above, the solid electrolytic capacitor 1 comprises a capacitor laminate 10, a first terminal electrode 20, a second terminal electrode 30, and an insulating resin body 40.

[0053] As shown in Figure 1, the multiple capacitor elements 11-14 are stacked in the order of capacitor element 14, capacitor element 13, capacitor element 12, and capacitor element 11, from the bottom side to the top side of the solid electrolytic capacitor 1. Capacitor elements 11 and 14 correspond to the "first capacitor elements," and capacitor elements 12 and 13 correspond to the "second capacitor elements."

[0054] The capacitor element in the bottom layer of the capacitor stack 10 is capacitor element 14, and the capacitor element in the top layer is capacitor element 11. Capacitor element 14 and capacitor element 13 are adjacent along the stacking direction, capacitor element 13 and capacitor element 12 are adjacent along the stacking direction, and capacitor element 12 and capacitor element 11 are adjacent along the stacking direction.

[0055] The capacitor element 11 comprises an anode 111, a dielectric layer 112, a conductive polymer layer 113, and a conductive layer 114. The capacitor element 11 has substantially the same configuration as the capacitor element 12 described above, but has a protrusion 119 on only one side in the thickness direction.

[0056] The capacitor element 12 has the configuration described above and is provided with protrusions 129 on both sides in the thickness direction.

[0057] The capacitor element 13 comprises an anode 131, a dielectric layer 132, a conductive polymer layer 133, and a conductive layer 134. The capacitor element 13 has the same configuration as the capacitor element 12 described above, and has protrusions 139 on both sides in the thickness direction.

[0058] The capacitor element 14 comprises an anode 141, a dielectric layer 142, a conductive polymer layer 143, and a conductive layer 144. The capacitor element 14 has substantially the same configuration as the capacitor element 12 described above, but has a protrusion 149 on only one side in the thickness direction.

[0059] The conductive layer 114 of capacitor element 11 and the conductive layer 124 of capacitor element 12 are in contact. A portion of the plate-shaped second terminal electrode 30 is sandwiched between the conductive layer 124 of capacitor element 12 and the conductive layer 134 of capacitor element 13. The conductive layer 134 of capacitor element 13 and the conductive layer 144 of capacitor element 14 are in contact.

[0060] The anodes 111 of capacitor element 11, 121 of capacitor element 12, 131 of capacitor element 13, and 141 of capacitor element 14 are bundled together and joined to a plate-shaped first terminal electrode 20.

[0061] The capacitor laminate 10, a portion of the first terminal electrode 20, and a portion of the second terminal electrode 30, which have this configuration, are sealed with an insulating resin body 40. The insulating resin body 40 has a roughly rectangular parallelepiped shape with a top surface 401, a bottom surface 402, a first end surface 403, and a second end surface 404.

[0062] The first terminal electrode 20 is exposed to the outside from the first end face 403 of the insulating resin body 40 and is arranged bent along the first end face 403 and the bottom face 402. The second terminal electrode 30 is exposed to the outside from the second end face 404 of the insulating resin body 40 and is arranged bent along the second end face 404 and the bottom face 402.

[0063] The first terminal electrode 20 and the second terminal electrode 30 are preferably made of a metal material that is easy to bend and has high conductivity. The first terminal electrode 20 and the second terminal electrode 30 are made of a material cut from, for example, a metal sheet. The first terminal electrode 20 and the second terminal electrode 30 may be made of the same material or of different materials.

[0064] The insulating resin body 40 is mainly resin and may contain fillers. Preferred resins include epoxy resins, phenolic resins, polyimide resins, silicone resins, polyamide resins, and liquid crystal polymers. The resin can be in solid or liquid form. It is preferable that the corners and edges are rounded by barrel polishing after resin encapsulation. Preferred fillers include silica particles, alumina particles, and metal particles. The maximum diameter of the fillers is preferably, for example, 30 μm or more and 40 μm or less. It is more preferable that the solid epoxy resin and phenolic resin contain silica particles.

[0065] Figures 5(A) and 5(B) are enlarged cross-sectional views showing the protruding parts when multiple capacitor elements are stacked. Figure 5(A) shows the state before adjacent capacitor elements come into contact, and Figure 5(B) shows the state after adjacent capacitor elements come into contact. The state shown in Figure 5(B) represents the state of the capacitor stack 10 in the solid electrolytic capacitor 1.

[0066] By adopting the above configuration, as shown in Figures 5(A) and 5(B), the protrusion 119 of capacitor element 11 and the protrusion 129 of capacitor element 12 face each other. The protrusion 129 of capacitor element 12 and the protrusion 139 of capacitor element 13 face each other. The protrusion 139 of capacitor element 13 and the protrusion 149 of capacitor element 14 face each other.

[0067] In this state, when forming the capacitor stack 10, pressure is applied to the stacked capacitor elements 11-14 from above and below, sandwiching them. In this case, the portions forming the respective protrusions 119, 129, 139, and 149 come into contact with each of the conductive layers 114, 124, 134, and 144 of the stacked capacitor elements 11, 12, 13, and 14. Further pressure is then applied to the stacked capacitor elements 11-14, causing the protrusions 119, 129, 139, and 149, each formed by a conductive polymer layer, to be crushed, as shown in Figure 5(B).

[0068] This ensures a predetermined contact area for adjacent conductive layers 114, 124, 134, and 144. Therefore, the capacitor laminate 10 can achieve stable electrical and physical connections between adjacent conductive layers 114, 124, 134, and 144.

[0069] Thus, the solid electrolytic capacitor 1 can connect adjacent capacitor elements 11-14 in a physically and electrically stable manner without the need to use a conductive adhesive separately.

[0070] As a result, the solid electrolytic capacitor 1 avoids the various problems that arise when using conductive adhesives, and can achieve the unique effects of the solid electrolytic capacitor 1.

[0071] For example, conductive adhesives are usually supplied in paste form, but if too much is applied, the thickness of the capacitor laminate 10 becomes undesirably thick. As a result, the capacitor laminate 10 is exposed from the insulating resin body 40, resulting in a defective product.

[0072] However, since the solid electrolytic capacitor 1 does not use a conductive adhesive, it is possible to prevent the capacitor laminate 10 from becoming undesirably thick. As a result, the solid electrolytic capacitor 1 can more reliably cover the capacitor laminate 10 with the insulating resin body 40.

[0073] In particular, in the above configuration, the uppermost capacitor element 11 and the lowermost capacitor element 14 do not have protrusions that extend outward from the capacitor laminate 10. As a result, the solid electrolytic capacitor 1 can more reliably cover the capacitor laminate 10 with the insulating resin body 40, enabling further thinning.

[0074] Furthermore, if the amount of conductive adhesive is too large, it may overflow from the sides of the capacitor laminate 10. However, since the solid electrolytic capacitor 1 does not require the use of conductive adhesive, such overflow does not occur.

[0075] Furthermore, when conductive adhesives are used, the adhesive may unintentionally fall onto the manufacturing equipment, potentially leading to contamination problems. However, since solid electrolytic capacitor 1 does not require the use of conductive adhesives, the contamination problem can be avoided.

[0076] Furthermore, if there is insufficient conductive adhesive, the adhesive strength between adjacent capacitor elements will decrease. This can lead to delamination, for example, from the corners and edges on the cathode side of the capacitor element, resulting in increased ESR and reduced reliability. However, since solid electrolytic capacitor 1 does not require the use of conductive adhesive, delamination and increased ESR can be avoided.

[0077] In particular, in the above configuration, the protrusions are concentrated at the cathode-side end. This allows the solid electrolytic capacitor 1 to further avoid delamination and an increase in ESR. Also, in the above configuration, the protrusions are formed near the corners and edges on the cathode side, along the corners and edges. This allows the solid electrolytic capacitor 1 to further avoid delamination and an increase in ESR.

[0078] Furthermore, conductive adhesives often have relatively high resistivity. However, since solid electrolytic capacitor 1 does not require the use of conductive adhesive, it can achieve low ESR.

[0079] Furthermore, since the solid electrolytic capacitor 1 does not require the use of conductive adhesive, the number of components can be reduced, making manufacturing easier. The reduced number of components also contributes to lowering the cost of the solid electrolytic capacitor 1.

[0080] Furthermore, in the above configuration, the protrusions 129 and 139 can also be used for connection to the second terminal electrode 30. This makes the electrical and physical connection between the multiple capacitor elements 12 and 13 and the second terminal electrode 30 more stable.

[0081] Furthermore, in the above configuration, the capacitor elements 12 and 13 in the middle of the stacking direction have protrusions 129 and 139 on both sides, but it is also possible to have them on only one side. However, by providing protrusions on both sides, electrical and physical connections can be ensured with lower pressure. As a result, the solid electrolytic capacitor 1 can reduce damage to the anode due to pressure.

[0082] Furthermore, in the above configuration, the protrusion comprises a first protrusion extending along the second direction DIR2 and a second protrusion extending along the first direction DIR1. However, the protrusion only needs to have one of the first and second protrusions, and preferably it has at least the first protrusion.

[0083] Furthermore, in the above configuration, a conductive layer 124 consisting of a carbon layer 1241 and a silver layer 1242 covers the protrusion 129. This improves the connection reliability of adjacent capacitor elements and enables further reduction of ESR.

[0084] Furthermore, a configuration in which the silver layer 1242 contains silver powder and amorphous resin can suppress ESR degradation during reflow soldering. Amorphous resin does not have crystalline parts and has no melting point, so there is no volume increase when heated. Also, since there is no shrinkage due to recrystallization that occurs when it cools and solidifies, the rate of volume change with respect to temperature changes is smaller than that of crystalline resin.

[0085] Therefore, the shear stress at the interface between the silver layer 1242 and other material layers such as the carbon layer 1241 in contact with it, and the silver layer of another capacitor element, is reduced, and a stable contact state between the material layers is maintained, thereby suppressing ESR degradation.

[0086] Examples of environments in which the solid electrolytic capacitor 1 is heated and cooled include processes such as heating and pressurizing multiple capacitor elements to form a laminate, resin sealing of the laminate, reflow soldering when mounting the resin-sealed solid electrolytic capacitor onto a substrate, and changes in the operating environment of the mounted product.

[0087] Furthermore, the above-described configuration shows a case where the thickness of the capacitor element, i.e., the thickness of the structure consisting of the anode, dielectric layer, conductive polymer layer, and conductive layer, is constant except for the protrusions. However, in this structure, the second region RE2 may be thicker than the first region RE1, excluding the protrusions. Also, in this structure, the thickness may increase as it approaches the cathode side end. This allows the multiple capacitor elements 11, 12, 13, and 14 to be arranged at an angle such that the ends of the multiple capacitor elements 11, 12, 13, and 14 on the side where the anodes of each element are exposed converge towards the center of the capacitor stack 10 in the height direction (thickness direction). This makes it possible to reduce, for example, the amount of curvature (bending) of the anodes 111 and 141 in the capacitor elements 11 and 14. Therefore, damage to the anodes 111 and 141 can be suppressed.

[0088] (Manufacturing method for capacitor elements) Figures 6(A), 6(B), 6(C), 6(D), and 6(E) are plan views showing the state of each manufacturing process of the capacitor element according to the first embodiment.

[0089] First, as shown in Figure 6(A), the anode 121 is cut to a predetermined size. The anode 121 already has a dielectric layer 122 formed on it by oxidizing its surface in an aqueous solution containing boric acid, phosphoric acid, adipic acid, or their sodium salts, ammonium salts, etc., to form an oxide film on the surface.

[0090] Next, as shown in Figure 6(B), a strip-shaped mask MK for the conductive polymer layer 123 and the conductive layer 124 is applied by screen printing at a predetermined distance from one end 121EL1 of the anode body 121.

[0091] Next, as shown in Figure 6(C), a conductive polymer layer 123 is applied to the other end 121EL2 of the anode body 121 by DIP coating.

[0092] Next, as shown in Figure 6(D), a protrusion 129 is formed on the conductive polymer layer 123 using a dispenser or the like.

[0093] Next, as shown in Figure 6(E), a conductive layer 124 is formed by sequentially applying a carbon layer and a silver layer by DIP coating so as to cover the conductive polymer layer 123 on which the protrusions 129 are formed.

[0094] [Second Embodiment] A solid electrolytic capacitor according to a second embodiment of the present invention will be described with reference to the figures. Figure 7(A) is a plan view of the capacitor element according to the second embodiment, and Figure 7(B) is a side cross-sectional view.

[0095] As shown in Figures 7(A) and 7(B), the capacitor laminate and solid electrolytic capacitor according to the second embodiment differ from the capacitor laminate and solid electrolytic capacitor according to the first embodiment in the configuration of the capacitor elements that constitute them. Other configurations of the capacitor laminate and solid electrolytic capacitor according to the second embodiment are the same as those of the capacitor laminate and solid electrolytic capacitor according to the first embodiment, and the description of the similar parts will be omitted.

[0096] The capacitor elements constituting the capacitor laminate and solid electrolytic capacitor according to the second embodiment have a similar configuration, and in the following description, we will use capacitor element 12A in comparison to capacitor element 12 according to the first embodiment.

[0097] The capacitor element 12A according to the second embodiment differs from the capacitor element 12 according to the first embodiment in that the protrusion 129 is exposed from the conductive layer 124. The other components of the capacitor element 12A are the same as those of the capacitor element 12, and a description of the similar parts will be omitted.

[0098] The conductive layer 124 has an opening OP124A through which the protrusion 129 is inserted. The protrusion 129 passes through the opening OP124A and protrudes outward from the surfaces 124F1 and 124F2 of the conductive layer 124.

[0099] With this configuration, the capacitor laminate and solid electrolytic capacitor according to the second embodiment provide the same effects and advantages as the capacitor laminate 10 and solid electrolytic capacitor 1 according to the first embodiment.

[0100] Furthermore, this configuration allows for direct connection of the conductive polymer layers of adjacent capacitor elements. As a result, the resistance at the connection point can be minimized.

[0101] This configuration can be achieved, for example, by applying a liquid repellent to the surface of the protrusion 129 when forming the carbon layer 1241 and the silver layer 1242.

[0102] [Third Embodiment] A solid electrolytic capacitor according to a third embodiment of the present invention will be described with reference to the figures. Figure 8(A) is a plan view of the capacitor element according to the third embodiment, and Figure 8(B) is a side cross-sectional view.

[0103] As shown in Figures 8(A) and 8(B), the capacitor laminate and solid electrolytic capacitor according to the third embodiment differ from the capacitor laminate and solid electrolytic capacitor according to the first embodiment in the configuration of the capacitor elements that constitute them. The other configurations of the capacitor laminate and solid electrolytic capacitor according to the third embodiment are the same as those of the capacitor laminate and solid electrolytic capacitor according to the first embodiment, and the description of the similar parts will be omitted.

[0104] The capacitor elements constituting the capacitor laminate and solid electrolytic capacitor according to the second embodiment have a similar configuration, and in the following description, we will use capacitor element 12B in comparison to capacitor element 12 according to the first embodiment.

[0105] The capacitor element 12B according to the third embodiment differs from the capacitor element 12 according to the first embodiment in that the protrusion 129 is covered only by the carbon layer 1241 and not by the silver layer 1242. The other components of the capacitor element 12B are the same as those of the capacitor element 12, and a description of the similar parts will be omitted.

[0106] The silver layer 1242 of the conductive layer 124 has an opening OP124B through which a protrusion 129 covered with a carbon layer 1241 is inserted. The protrusion 129 covered with the carbon layer 1241 is inserted through the opening OP124B and protrudes outward from the surfaces 124F1 and 124F2 of the conductive layer 124.

[0107] With this configuration, the capacitor laminate and solid electrolytic capacitor according to the third embodiment provide the same effects and advantages as the capacitor laminate 10 and solid electrolytic capacitor 1 according to the first embodiment.

[0108] Furthermore, in this configuration, the carbon layers of adjacent capacitor elements are directly connected to each other, improving connection reliability through the anchoring effect.

[0109] This configuration can be achieved, for example, by applying a liquid repellent to the surface of the protrusion 129 covered with the carbon layer 1241 during the formation of the silver layer 1242.

[0110] [Fourth Embodiment] A solid electrolytic capacitor according to a fourth embodiment of the present invention will be described with reference to the figures. Figure 9 is a side cross-sectional view of the solid electrolytic capacitor according to the fourth embodiment.

[0111] As shown in Figure 9, the solid electrolytic capacitor 1C according to the fourth embodiment differs from the solid electrolytic capacitor 1 according to the first embodiment in the capacitor laminate 10C, the first terminal electrode 20C, and the second terminal electrode 30C. Below, only the differences from the solid electrolytic capacitor 1 will be described.

[0112] The capacitor laminate 10C comprises multiple capacitor elements 11, 12, 13, and 14C. Capacitor element 14C, like capacitor elements 12 and 13, has protrusions on both sides.

[0113] The anodes of multiple capacitor elements 11, 12, 13, and 14C are bundled together. This bundled portion is connected to the first terminal electrode 20C.

[0114] The second terminal electrode 30C has a flat base portion 309. The capacitor laminate 10C is placed on the base portion 309. In this case, the protrusions of the capacitor element 14C are crushed. This improves the reliability of the connection between the capacitor element 14C and the base portion 309.

[0115] The configurations shown in each of the embodiments described above can be combined as appropriate, and each combination can produce different effects. [Explanation of Symbols]

[0116] 1. 1C: Solid electrolytic capacitor 10, 10C: Capacitor stack 11, 12, 12A, 12B, 13, 14, 14C: Capacitor elements 20, 20C: 1st terminal electrode 30, 30C: 2nd terminal electrode 40: Insulating resin 111, 121, 131, 141: Anodes 112, 122, 132, 142: Dielectric layer 113, 123, 133, 143: Conductive polymer layer 114, 124, 134, 144: Conductive layer 119, 129, 139, 149: Convex part 1241: Carbon layer 1242: Silver layer 1291: First protrusion 1292: Second protrusion 124CN1, 124CN2: Ridge OP124A, OP124B: Opening

Claims

1. A capacitor laminate comprising multiple capacitor elements, each consisting of a flat film, stacked so that their respective flat film surfaces overlap, The aforementioned capacitor element is an anode body composed of a membrane-like valve-acting metal, A dielectric layer covering the anode body, A conductive polymer layer covering the dielectric layer, A conductive layer covering the conductive polymer layer, formed with a predetermined area including the other end but not including one end in the first direction of the anode body, and having a first end on the side of the one end and a second end on the side of the other end, Equipped with, The conductive layer and the conductive polymer layer have a first region on the first end side and a second region on the second end side in the plane on which the conductive layer is formed. The conductive polymer layer has a first convex portion that extends in a direction perpendicular to the first direction in the second region and protrudes toward the conductive layer side, The first protrusions of adjacent capacitor elements in the plurality of capacitor elements overlap at least partially when viewed in the stacking direction. The adjacent capacitor elements in the plurality of capacitor elements are connected through their respective first protrusions. The conductive layer has a silver layer on its outermost surface. The aforementioned silver layer is composed of a layer containing silver powder and amorphous resin. Stacked capacitors.

2. The height of the first protrusion is greater than the thickness of the conductive layer. The capacitor laminate according to claim 1.

3. The anode body includes a second protrusion that extends in a direction parallel to the first direction and protrudes toward the conductive layer side, A capacitor laminate according to claim 1 or claim 2.

4. The second protrusion is composed of a third protrusion and a fourth protrusion running parallel to each other. The third protrusion is formed parallel to and close to the first side end of the anode body that is parallel to the first direction, The fourth protrusion is formed parallel to the first direction in the anode body and close to and parallel to the second side end opposite to the first side end. The capacitor laminate according to claim 3.

5. The first protrusion and the third protrusion are formed along the first corner where the first end and the first side end intersect. The first protrusion and the fourth protrusion are formed along the second corner where the first end and the second side end intersect. The capacitor laminate according to claim 4.

6. The conductive layer covers the first protrusion, A capacitor laminate according to claim 1 or claim 2.

7. The plurality of capacitor elements comprises first capacitor elements located at both ends in the stacking direction and second capacitor elements positioned between the first capacitor elements. The first capacitor element has the first protrusion only on the surface where adjacent capacitor elements exist, The second capacitor element has the first protrusions on both sides, A capacitor laminate according to any one of claims 1 to 6.

8. The conductive layer further comprises a carbon layer formed on the outer surface of the conductive polymer layer, and the silver layer is formed on the outer surface of the carbon layer. A capacitor laminate according to any one of claims 1 to 7.

9. The portion of the capacitor element corresponding to the second region is thicker than the portion of the capacitor element corresponding to the first region. A capacitor laminate according to any one of claims 1 to 8.

10. A capacitor laminate according to any one of claims 1 to 9, An insulating resin body covering the capacitor laminate, A first terminal electrode having a portion exposed on the outer surface of the insulating resin body and connected to the anodes of the plurality of capacitor elements, A second terminal electrode having a portion exposed on the outer surface of the insulating resin body and connected to the conductive layer of the plurality of capacitor elements, A solid electrolytic capacitor equipped with the following features.

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