Solid electrolytic capacitor and method for manufacturing a solid electrolytic capacitor

Abstract

Disclosed is a production method for a solid electrolytic capacitor including at least one solid electrolytic capacitor element 100 that includes: a negative electrode part 130; and a positive electrode part 110 that includes a positive electrode drawn-out section 111a. Said production method comprises: (i) a step for connecting one positive electrode connection member 211 composed of a metal other than a valve metal to the positive electrode drawn-out section 111a of the at least one solid electrolytic capacitor element 100; a step (ii) for forming an exterior body 140 so as to cover the at least one solid electrolytic capacitor element 100 and at least a portion of the positive electrode connection member 211; a step (iii) for exposing, from the exterior body 140, a portion of a surface of the positive electrode connection member 211 as a connection surface 211a by removing a portion of the exterior body 140; and a step (iv) for connecting a positive electrode lead terminal 212 and the connection surface 211a to each other.

Description

Technical Field

[0001] The present disclosure relates to a solid electrolytic capacitor and a method for manufacturing a solid electrolytic capacitor.

Background Art

[0002] A solid electrolytic capacitor generally includes a solid electrolytic capacitor element, lead terminals connected to the solid electrolytic capacitor element, and an exterior body that seals the solid electrolytic capacitor element. Regarding the connection form between the lead terminals and the solid electrolytic capacitor element, various proposals have been made conventionally.

[0003] Patent Document 1 (Japanese Patent Publication No. 2013-515381) discloses "forming an anode including valve metal or a conductive oxide of valve metal, forming the anode such that an anode lead extension protrudes from the anode, forming a dielectric on the anode, forming a cathode layer on the dielectric, accommodating the anode, the dielectric, and the cathode layer in a non-conductive material container, exposing the anode lead extension on the outer side surface of the container, adhering a conductive metal layer to the anode lead extension, and electrically connecting a preformed solid metal terminal to the conductive metal layer on the side surface, a method for forming a solid electrolytic capacitor."

[0004] Patent Document 2 (Japanese Unexamined Patent Application Publication No. 2008-235413) discloses "a solid electrolytic capacitor including a flat element using a conductive polymer as a solid electrolyte and having an anode electrode part and a cathode electrode part provided via an insulating part, anode comb terminals and cathode comb terminals obtained by joining the anode electrode part and the cathode electrode part provided on this element respectively, and an insulating exterior resin that integrally covers the element, the anode comb terminals, and the cathode comb terminals in a state where a part of each of the anode comb terminals and the cathode comb terminals is exposed, in which notch parts are provided at both ends of the end part of the cathode electrode part in the direction connecting the anode electrode part and the cathode electrode part of the element, and side wall parts are provided by bending both ends of the element mounting part of the cathode comb terminal on which the cathode electrode part of the element is mounted so as to contact the side surfaces of the notch parts provided in the cathode electrode part of the element."

[0005] Patent Document 3 (Japanese Patent Publication No. 2004-87893) discloses a "solid electrolytic capacitor comprising: an anode body made of valve-acting metal separated into an anode portion and a cathode portion by an insulating portion, a dielectric oxide film layer, a solid electrolyte layer, and a cathode layer sequentially laminated on the surface of the cathode portion; an anode comb terminal to which the anode portions of each capacitor element are integrally connected when multiple capacitor elements are laminated together; a cathode comb terminal to which the cathode portions of each capacitor element are integrally connected; and an insulating outer resin that integrally covers the multiple capacitor elements with a portion of the anode comb terminal and cathode comb terminal exposed on the outer surface, wherein the connection between the anode portion of each capacitor element and the anode comb terminal is joined by resistance welding through a through hole provided on the joint surface of the anode comb terminal on which the anode portion of the capacitor element is mounted." [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Special Publication No. 2013-515381 [Patent Document 2] Japanese Patent Publication No. 2008-235413 [Patent Document 3] Japanese Patent Publication No. 2004-87893 [Overview of the project] [Problems that the invention aims to solve]

[0007] Currently, there is a demand for further improvement in the volumetric capacitance density (capacitance per unit volume) of solid electrolytic capacitors. One of the objectives of this disclosure is to provide a solid electrolytic capacitor with high volumetric capacitance density and a method for manufacturing the same. [Means for solving the problem]

[0008] One aspect of this disclosure relates to a method for manufacturing a solid electrolytic capacitor. The manufacturing method is a method for manufacturing a solid electrolytic capacitor comprising at least one solid electrolytic capacitor element including a cathode portion and an anode portion including an anode lead portion, Step (i) of connecting one anode connecting member made of a metal other than valve metal to the anode lead portion of the at least one solid electrolytic capacitor element, (ii) A step of forming an outer casing so as to cover the at least one solid electrolytic capacitor element and at least a part of the anode connecting member, (iii) A step of removing a part of the outer casing to expose a part of the surface of the anode connecting member as a connecting surface from the outer casing, The process includes (iv) connecting the anode lead terminal to the connection surface of the anode connecting member.

[0009] Another aspect of this disclosure relates to a solid electrolytic capacitor. This solid electrolytic capacitor is At least one solid electrolytic capacitor element, A single anode connecting member made of a metal other than valve metal, The at least one solid electrolytic capacitor element and the outer casing arranged to cover the anode connecting member, Including the anode lead terminals that are exposed to the outside, The solid electrolytic capacitor element includes a cathode portion and an anode portion including an anode lead portion. The anode connecting member is connected to the anode lead-out section, A portion of the surface of the anode connecting member is exposed from the outer casing as a connecting surface. The connection surface of the anode connecting member and the anode lead terminal are connected. [Effects of the Invention]

[0010] According to this disclosure, a solid electrolytic capacitor with high volumetric capacitance density can be obtained. The novel features of the present invention are described in the appended claims, but the present invention will be better understood with reference to the following detailed description taken in conjunction with the drawings, both as to its construction and its content, and other objects and features of the present invention.

Brief Description of the Drawings

[0011] [Figure 1A] FIG. 1A schematically shows one step of an example of the manufacturing method of Embodiment 1. [Figure 1B] FIG. 1B schematically shows one step following the step of FIG. 1A. [Figure 1C] FIG. 1C schematically shows one step following the step of FIG. 1B. [Figure 1D] FIG. 1D schematically shows an example of a solid electrolytic capacitor manufactured by the manufacturing method of Embodiment 1. [Figure 2] FIG. 2 schematically shows a cross section of an example of a solid electrolytic capacitor element used in the manufacturing method of Embodiment 1. [Figure 3A] FIG. 3A schematically shows an example of the shape of a connection surface exposed by step (iii). [Figure 3B] FIG. 3B schematically shows an example of step (iii-b). [Figure 4] FIG. 4 schematically shows another example of a solid electrolytic capacitor manufactured by the manufacturing method of Embodiment 1. [Figure 5A] FIG. 5A schematically shows one step of another example of the manufacturing method of Embodiment 1. [Figure 5B] FIG. 5B schematically shows another example of a solid electrolytic capacitor manufactured by the manufacturing method of Embodiment 1. [Figure 6A] FIG. 6A schematically shows one step of the manufacturing method of Embodiment 2. [Figure 6B] FIG. 6B schematically shows an example of a solid electrolytic capacitor manufactured by the manufacturing method of Embodiment 2. [Figure 7] FIG. 7 schematically shows a cross section of an example of a solid electrolytic capacitor element used in the manufacturing method of Embodiment 2.

Modes for Carrying Out the Invention

[0012] Hereinafter, embodiments according to the present disclosure will be described with examples, but the present disclosure is not limited to the examples described below. In the following description, specific numerical values and materials may be exemplified, but other numerical values and other materials may be applied as long as the effects of the present disclosure can be obtained. In this specification, the description "numerical value A to numerical value B" includes numerical value A and numerical value B and can be read as "numerical value A or more and numerical value B or less". In the following description, when the lower limit and the upper limit of a numerical value regarding a specific physical property or condition are exemplified, any combination of any of the exemplified lower limits and any of the exemplified upper limits can be made as long as the lower limit is not more than the upper limit. In the following description, when examples of components and examples of methods are listed, any one of the listed examples may be used, or a plurality of the listed examples may be used in combination, unless otherwise specified. In this specification, the form in which two members are connected includes a form in which two members are directly connected and a form in which two members are connected via a layer or the like. Examples of the layer include a conductive layer (such as a solder layer or a metal paste layer).

[0013] (Method for manufacturing a solid electrolytic capacitor) The manufacturing method of the present embodiment is a method for manufacturing a solid electrolytic capacitor including at least one solid electrolytic capacitor element including a cathode portion and an anode portion including an anode lead-out portion. The manufacturing method may be referred to as "manufacturing method (M)" hereinafter. The solid electrolytic capacitor manufactured by the manufacturing method (M) is not particularly limited.

[0014] The manufacturing method (M) includes steps (i), step (ii), step (iii), and step (iv) in this order. These steps will be described later. In the manufacturing method (M), the anode lead-out portion and the anode lead terminal are connected via one anode connection member made of a metal that is not a valve metal (a metal having no valve action). Therefore, the connection between the anode connection member and the anode lead terminal is easy, and the anode connection member and the anode lead terminal can be firmly connected with high reliability.

[0015] Furthermore, if the solid electrolytic capacitor includes multiple solid electrolytic capacitor elements, in step (i), the ends of the anode lead-out sections are connected together to a single anode connecting member. Therefore, compared to connecting each end to separate anode connecting members, manufacturing costs and time can be significantly reduced.

[0016] (Step (i)) Step (i) is the step of connecting one anode connecting member made of a metal that is not a valve metal (a metal that does not have a valve function) to the anode lead portion of the at least one solid electrolytic capacitor element. Examples of anode lead portions include a part of the anode foil (anode body) and the anode wire, which will be described later.

[0017] A metal with valve properties is a metal that exhibits rectifying properties due to a relatively stable oxide film formed on its surface. These metals are also called valve metals. Examples of valve metals include titanium, tantalum, aluminum, and niobium. A metal without valve properties is simply a metal that is not a valve metal. Examples of metals without valve properties include copper and copper alloys. That is, a metal without valve properties may be at least one selected from the group consisting of copper and copper alloys, or it may be copper or a copper alloy. Copper and copper alloys are preferred because they have high conductivity and are easy to connect.

[0018] The method of connecting the anode connecting member and the anode lead-out section is not particularly limited, and known methods may be used. Examples of connection methods include welding, connection using conductive paste, and connection using solder. Examples of welding include laser welding, resistance welding, and other welding methods (the same applies to welding described below). The conductive paste may be a mixture of resin and conductive particles (such as carbon particles or metal particles). The conductive paste may also be a metal paste containing metal particles (for example, silver paste).

[0019] The solid electrolytic capacitor element is not particularly limited. Examples of solid electrolytic capacitor elements include capacitors in which the anode portion includes valve metal foil, and capacitors in which the anode portion includes a sintered body. That is, the anode portion may include a sintered body containing valve metal.

[0020] Solid electrolytic capacitor elements may be formed by known methods. A solid electrolytic capacitor may contain one or more solid electrolytic capacitor elements. There is no upper limit to the number of solid electrolytic capacitor elements in a solid electrolytic capacitor; it may be 10 or less. Multiple solid electrolytic capacitor elements are usually connected in parallel.

[0021] A solid electrolytic capacitor may include multiple stacked solid electrolytic capacitor elements. In that case, in step (i), the ends of the anode leads of the multiple solid electrolytic capacitor elements may be connected together to the anode connecting member. For example, if the anode leads are made of metal foil, the ends of multiple anode leads may be stacked and connected to the anode connecting member. The ends of the anode leads are connected to each other. The method of connection is not particularly limited. Examples of connection methods include welding, using metal paste (e.g., silver paste), and soldering. Alternatively, the ends of the anode leads may be physically connected by methods such as enclosing them with the anode connecting member.

[0022] When a solid electrolytic capacitor includes multiple stacked solid electrolytic capacitor elements, the anode connecting member may be sandwiched between multiple stacked anode lead-out portions, and the cathode connecting member may be sandwiched between multiple stacked cathode portions.

[0023] (Step (ii)) Step (ii) is a step of forming an outer casing so as to cover the at least one solid electrolytic capacitor element and at least a portion of the anode connecting member. There are no particular limitations on the outer casing or the method of forming the outer casing, and known outer casings and known methods may be used. Examples of outer casings will be described later. The outer casing may be formed using molding techniques such as transfer molding, compression molding, or injection molding. The outer casing formed in step (ii) includes a portion that will become the outer casing of the manufactured solid electrolytic capacitor and a portion that will be removed in step (iii).

[0024] (Step (iii)) Step (iii) is a step of removing a portion of the casing to expose a portion of the surface of the anode connecting member as a connecting surface from the casing. Step (iii) usually includes a cutting step of cutting a portion of the casing. By having step (iii), the volume of the casing can be reduced without changing the volume of the portion that generates capacitance of the solid electrolytic capacitor element, and the volumetric capacitance density can be increased. The removal (e.g., cutting) of the casing is carried out in such a way that the length of the casing in direction LD (see Figure 1B) is shortened. For example, the casing (and the anode connecting member, if necessary) may be cut along a direction perpendicular to direction LD.

[0025] The method for performing the cutting process is not particularly limited. The cutting process may be performed using a blade (for example, a circular blade). For example, the cutting process may be performed using a dicing blade used for cutting semiconductor wafers. In other words, the cutting process may be performed using a dicer or similar device used for cutting semiconductor wafers.

[0026] The width of the cut is not particularly limited. Furthermore, the distance L between the cathode and the cut surface after cutting is not particularly limited. A shorter distance L allows for a higher volumetric density.

[0027] Step (iii) may include step (iii-a) of removing a portion of the outer casing by cutting the outer casing and the anode connecting member together. The cutting step of step (iii-a) allows a portion of the surface of the anode connecting member to be exposed from the outer casing as a connecting surface.

[0028] Step (iii) may further include step (iii-b), which involves removing the portion of the outer casing exposed at the cut surface after step (iii-a), thereby causing a portion of the anode connecting member to protrude from the outer casing. By causing a portion of the anode connecting member to protrude from the outer casing, the area of ​​the anode connecting member exposed from the outer casing (the area of ​​the contact surface) can be increased. As a result, the connection between the anode connecting member and the anode lead terminal can be made easier and stronger.

[0029] The method for performing step (iii-b) is not particularly limited. Examples of methods for performing step (iii-b) include sandblasting and laser irradiation (such as laser ablation). The length (height) H to which the anode connecting member protrudes from the outer casing by step (iii-b) may be 50 μm or more, or 100 μm or more. By setting the length H to 50 μm or more, the connection between the anode connecting member and the anode lead terminal can be made particularly easy and strong. The upper limit of the length H is not particularly limited, but from the viewpoint of manufacturing cost and manufacturing time, it may be 200 μm or less, or 150 μm or less.

[0030] When performing step (iii-b), the entire surface of the outer casing at the cut end may be removed, or only a portion of the surface of the outer casing at the cut end may be removed. For example, a portion of the surface of the outer casing at the cut end may be removed in a groove-like manner. The relationship between the width of the formed groove, the width of the connection surface, and the width of the anode lead terminal will be explained in Embodiment 1.

[0031] (Step (iv)) Step (iv) is the step of connecting the anode lead terminal to the connection surface of the anode connecting member. Step (iv) electrically connects the anode portion and the anode lead terminal via the anode connecting member. The method of connecting the anode lead terminal and the connection surface of the anode connecting member is not particularly limited. Examples of such connection methods include welding, using metal paste (e.g., silver paste), and soldering. The anode lead terminal is attached from the outside; that is, the anode lead terminal is exposed to the outside.

[0032] The solder (e.g., solder paste) is not particularly limited, and known lead-free solder may be used. Solder with a high solidus temperature (lead-free solder) may be used. For example, solder that does not remelt in the reflow process performed when mounting electronic components may be used. By using such solder, it is possible to suppress the occurrence of disconnections and other problems in the reflow process. The solidus temperature of the solder with a high solidus temperature may be 230°C or higher, or 300°C or lower. Commercially available solder or known solder may be used for the solder with a high solidus temperature. Examples of high solder with a solidus temperature of 230°C or higher include Sn-Sb based Sn-5Sb or Sn-10Sb solder.

[0033] The above description explains the step of exposing a portion of the surface of the anode connecting member as a connecting surface by removing a portion of the outer casing. The manufacturing method (M) may further include the step of exposing a portion of the surface of the cathode connecting member as a connecting surface by removing a portion of the outer casing. This step makes it possible to further increase the volumetric capacity density. In that case, steps (i) to (iv) may be performed as follows. First, step (i) further includes the step of connecting one cathode connecting member made of a metal that is not a valve metal (a metal that does not have a valve function) to the cathode portion. Next, in step (ii), an outer casing is formed so as to cover the at least one solid electrolytic capacitor element, at least a portion of the anode connecting member, and at least a portion of the cathode connecting member. Next, step (iii) further includes the step of exposing a portion of the surface of the cathode connecting member from the outer casing as a connecting surface by removing another portion of the outer casing. Next, step (iv) further includes the step of connecting the cathode lead terminal to the connecting surface of the cathode connecting member.

[0034] The method for connecting the cathode connecting member to the cathode in step (i) is not limited and may be done by known methods. For example, a metal paste (e.g., silver paste) may be used to connect the two. Steps (ii) to (iv) can be carried out in the same manner as described for steps (ii) to (iv) with respect to the anode connecting member, so redundant explanations will be omitted. In step (iv), the cathode lead terminals are attached from the outside. That is, the cathode lead terminals are exposed to the outside.

[0035] A solid electrolytic capacitor is obtained by the manufacturing method (M). The anode lead terminal and cathode lead terminal function as connection terminals, respectively.

[0036] (Solid electrolytic capacitor) The solid electrolytic capacitor of this embodiment may be referred to as "solid electrolytic capacitor (E)" below. Solid electrolytic capacitor (E) can be manufactured by manufacturing method (M). Since the matters described for manufacturing method (M) are applicable to solid electrolytic capacitor (E), redundant explanations may be omitted. Furthermore, the matters described for solid electrolytic capacitor (E) may also be applied to manufacturing method (M). In addition, solid electrolytic capacitor (E) may be manufactured by methods other than manufacturing method (M).

[0037] The solid electrolytic capacitor (E) includes at least one solid electrolytic capacitor element, one anode connecting member made of a metal that is not a valve metal (a metal without valve function), an outer casing disposed to cover at least one solid electrolytic capacitor element and the anode connecting member, and an anode lead terminal exposed to the outside. The solid electrolytic capacitor element includes a cathode portion and an anode portion including an anode lead portion. The anode connecting member is connected to the anode lead portion. A portion of the surface of the anode connecting member is exposed from the outer casing as a connection surface. The connection surface of the anode connecting member is connected to the anode lead terminal.

[0038] According to the solid electrolytic capacitor (E), the volume of the casing can be reduced without changing the volume of the part that generates capacitance in the solid electrolytic capacitor element. Therefore, the volumetric capacitance density can be increased.

[0039] The solid electrolytic capacitor (E) may include multiple stacked solid electrolytic capacitor elements. In this case, the ends of the multiple anode leads of the multiple solid electrolytic capacitor elements may be grouped together and connected to an anode connecting member.

[0040] The anode portion may include a sintered body containing valve metal. Alternatively, the anode portion may include foil made of valve metal.

[0041] The portion of the anode connecting member may protrude from the outer casing. This configuration can be achieved by step (iii-b).

[0042] The solid electrolytic capacitor (E) may further include a cathode connecting member made of a non-valve metal (a metal without valve function) that is covered by an outer casing, and a cathode lead terminal exposed to the outside. The cathode connecting member may be connected to the cathode portion. A portion of the surface of the cathode connecting member may be exposed from the outer casing as a connection surface. The connection surface of the cathode connecting member and the cathode lead terminal may be connected.

[0043] Examples of components used in the solid electrolytic capacitor (E) and manufacturing method (M) of this embodiment are described below. Except for the parts characteristic of this disclosure, components of known solid electrolytic capacitors may be used in the solid electrolytic capacitor (E) and manufacturing method (M).

[0044] (Solid electrolytic capacitor element) A solid electrolytic capacitor element includes an anode portion, a cathode portion, and a dielectric layer. The cathode portion includes an electrolyte layer and may further include a cathode extraction layer.

[0045] (Anode part) The anode section includes an anode extraction section and an anode body. The anode extraction section and the anode body are electrically connected. The anode body can be formed using valve metal or a metal containing valve metal.

[0046] A metal foil (a foil containing valve metal, or a foil consisting of valve metal) may be used as the anode. The thickness of the metal foil (anode) is not particularly limited. For example, the thickness of the metal foil may be 15 μm or more, 80 μm or more, 300 μm or less, or 250 μm or less. At least a portion of the surface of the metal foil (anode) may be roughened by electrolytic etching or the like. In that case, the anode has a porous portion on its surface. A preferred example of a metal foil anode is aluminum foil. When the anode is a metal foil, one end of the metal foil can function as an anode lead-out portion.

[0047] The anode body may be a sintered body formed by sintering material particles. Examples of material particles include valve metal particles and valve metal-containing alloy particles. A preferred example of a sintered anode body is a sintered tantalum body. When the anode body is a sintered body, an anode wire may be used as the anode lead-out. One end of the anode wire is embedded in the sintered body, and the other end protrudes from the end face of the sintered body.

[0048] (Dielectric layer) The dielectric layer is formed on at least a portion of the surface of the anode. The dielectric layer may be formed, for example, by anodizing (anodic oxidation by chemical conversion treatment) the surface of the anode. In this case, the dielectric layer contains an oxide of the valve metal. For example, if aluminum is used as the valve metal, the dielectric layer may contain aluminum oxide. If a porous portion exists on the surface of the anode, the dielectric layer may be formed on at least a portion of the surface of the porous portion of the anode.

[0049] (Cathode part) The cathode portion includes an electrolyte layer and a conductive layer adjacent to the electrolyte layer. The conductive layer may be formed to cover at least a portion of the electrolyte layer, or it may be formed to cover the entire surface of the electrolyte layer. Examples of conductive layers include carbon-containing layers and metal-containing layers. The metal-containing layer can be formed from a metal paste (e.g., silver paste). The conductive layer may also include a carbon-containing layer formed on the electrolyte layer and a metal-containing layer (e.g., a silver-containing layer) formed on the carbon-containing layer.

[0050] (electrolyte layer) The electrolyte layer (solid electrolyte layer) is arranged to cover at least a portion of the dielectric layer. The electrolyte layer includes, for example, manganese compounds and conductive polymers. Examples of conductive polymers include polypyrrole, polythiophene, polyfuran, polyaniline, polyacetylene, polyphenylene, polyphenylenevinylene, polyacene, polythiophenevinylene, and their derivatives. A preferred example of a conductive polymer is poly(3,4-ethylenedioxythiophene).

[0051] The conductive polymer may be included in the solid electrolyte layer together with the dopant. A preferred example of the dopant is a polymer anion derived from polystyrene sulfonic acid. A preferred example of the electrolyte layer is formed using poly(3,4-ethylenedioxythiophene) (PEDOT) doped with polystyrene sulfonic acid (PSS).

[0052] (Anode connecting member and cathode connecting member) The anode and cathode connectors can each be made of a metal other than valve metal (e.g., copper, copper alloy, etc.). The thickness of the anode and cathode connectors may each be in the range of 25 μm to 200 μm (e.g., 25 μm to 100 μm). Thin metal sheets, which are known to be used for lead terminals, may be used to form the anode and cathode connectors.

[0053] (Exterior) The exterior body is not particularly limited, and known exterior bodies may be used. The exterior body includes an exterior resin. Examples of exterior resins include curable resins and engineering plastics. Examples of curable resins (e.g., thermosetting resins) include epoxy resins, phenolic resins, silicone resins, melamine resins, urea resins, alkyd resins, polyurethanes, and unsaturated polyesters. Engineering plastics include general-purpose engineering plastics and super engineering plastics. Examples of engineering plastics include polyimides and polyamide-imides.

[0054] The outer casing may contain other additives, such as inorganic fillers, in addition to the outer resin. That is, at least a portion of the outer casing may be composed of a resin composition. Examples of inorganic fillers include silica (such as fused silica), talc, calcium carbonate, and aluminum oxide.

[0055] Examples of embodiments relating to this disclosure will be specifically described below with reference to the drawings. Furthermore, the examples described below can be modified based on the above description. Also, the matters described below may be applied to the above embodiments. In addition, components that are not essential to the solid electrolytic capacitor of this disclosure may be omitted in the embodiments described below. For ease of understanding, some components may be omitted from the following figures.

[0056] (Embodiment 1) Embodiment 1 describes a method for manufacturing an example of a solid electrolytic capacitor that includes multiple solid electrolytic capacitor elements.

[0057] First, as shown in Figure 1A, a plurality of solid electrolytic capacitor elements 100 are stacked and connected to the anode connecting member 211 and the cathode connecting member 221 (step (i)). Step (i) may be carried out in the same manner as known methods for stacking a plurality of solid electrolytic capacitor elements 100 and connecting them to the anode lead terminals and cathode lead terminals. The anode connecting member 211 and the cathode connecting member 221 are connected to the sheet 200. The anode connecting member 211 and the cathode connecting member 221 can be formed by making cuts in a part of the sheet 200 and folding it. The sheet 200 is a sheet made of a metal that is not a valve metal (a metal that does not have a valve function).

[0058] The anode connecting member 211 includes a portion 211x that surrounds a plurality of stacked anode lead-out portions 111a. The cathode connecting member 221 includes two side wall portions 221y that are arranged to sandwich the sides of a plurality of stacked solid electrolytic capacitor elements 100. However, the shapes of the anode connecting member 211 and the cathode connecting member 221 may be other than those shown in Figure 1A.

[0059] Figure 2 schematically shows a cross-sectional view of an example of a solid electrolytic capacitor element 100. The solid electrolytic capacitor element 100 includes an anode portion 110 which includes an anode body (anode foil) 111 and an anode lead portion 111a, a dielectric layer 120 which covers at least a part of the anode body 111, and a cathode portion 130 which covers at least a part of the dielectric layer 120. The cathode portion 130 includes an electrolyte layer (solid electrolyte layer) 131 which covers at least a part of the dielectric layer 120, and a conductive layer 132 which is formed on the electrolyte layer 131.

[0060] The conductive layers 132 of multiple stacked solid electrolytic capacitor elements 100 are connected to each other. At least one conductive layer 132 is connected to a cathode connecting member 221 by a metal paste or the like. One end of the metal foil constituting the anode body 111 functions as an anode lead portion 111a. The anode lead portions 111a of multiple solid electrolytic capacitor elements 100 are stacked and connected to each other. At least one anode lead portion 111a is connected to an anode connecting member 211 by welding or the like.

[0061] Next, as shown in Figure 1B, an outer casing 140 is formed to cover the solid electrolytic capacitor element 100, at least a portion of the anode connecting member 211, and at least a portion of the cathode connecting member 221 (step (ii)). In Figure 1B, of the surfaces of the outer casing 140, the surface on the end face side of the anode lead-out portion 111a of the solid electrolytic capacitor element 100 is designated as the front surface 140f, and the surface opposite to the front surface 140f is designated as the rear surface 140r. The direction connecting the front surface 140f and the rear surface 140r is designated as direction LD.

[0062] Next, as shown in Figure 1C, a portion of the outer casing 140 is removed to expose a portion of the surface of the anode connecting member 211 as a connecting surface 211a from the outer casing 140 (step (iii)). Also, another portion of the outer casing 140 is removed to expose a portion of the surface of the cathode connecting member 221 as a connecting surface 221a from the outer casing 140. The removal of the outer casing is performed by cutting the outer casing 140 and the anode connecting member 211 together. The removal of the other portion of the outer casing is performed by cutting the outer casing 140 and the cathode connecting member 221 together. These cuts are made so as to shorten the length of the outer casing 140 in direction LD. These cuts form cut surfaces 140sa and 140sb. The connecting surface 211a is exposed at cut surface 140sa, and the connecting surface 221a is exposed at cut surface 140sb.

[0063] Figure 3A shows an example of the connection surface (end face) 211a of the anode connecting member 211 exposed in step (iii). The example connection surface 211a shown in Figure 3A has a C-shaped cross-section and surrounds the overlapping anode lead-out portions 111a. Such a connection surface 211a can be formed in step (i) by bending the anode connecting member 211 into a roughly cylindrical shape. This allows the anode lead-out portions 111a and the anode connecting member 211 to be firmly fixed together. Note that the shape of the connection surface 211a is not limited to the shape shown in Figure 3A, and may be roughly straight or roughly U-shaped. The shape of the connection surface 221a changes depending on the shape of the anode connecting member 211 in step (i).

[0064] When performing the above-described process (iii-b), the entire surface of the outer casing 140 at the cut surface 140sa (or cut surface 140sb) may be removed, or only a portion of the surface of the outer casing 140 at the cut surface 140sa (or cut surface 140sb) may be removed. An example of the case where only a portion of the outer casing 140 at the cut surface 140sa is removed is shown in Figure 3B. In the example shown in Figure 3B, a portion of the surface of the outer casing 140 at the cut surface 140sa is removed in a groove shape, forming a groove portion 140g. The width W2 of the groove portion 140g may be wider than the width W1 of the connection surface 211a and formed to accommodate the anode lead terminal 212. Specifically, the width W2 may be the same as or slightly larger than the width of the anode lead terminal 212. This allows a portion of the anode lead terminal 212 to be fitted into the groove portion 140g, making it easier to connect the anode lead terminal 212 to the connection surface 211a. Furthermore, the connection between the anode lead terminal 212 and the connection surface 211a is stabilized. Note that the width of the anode lead terminal 212 is wider than the width of the connection surface 211a, so the anode lead terminal 212 covers the entire connection surface 211a.

[0065] Next, as shown in Figure 1D, the anode lead terminal 212 is connected to the connection surface 211a of the anode connecting member 211 (step (iv)). Similarly, the cathode lead terminal 222 is connected to the connection surface 221a of the cathode connecting member 221. The anode lead terminal 212 and the cathode lead terminal 222 are each exposed to the outside; that is, they are exposed from the casing 140. Parts of the anode lead terminal 212 and parts of the cathode lead terminal 222 are positioned on the bottom surface 140b of the casing 140. These parts can function as terminals when the manufactured solid electrolytic capacitor 10 is mounted on a printed circuit board or the like. The anode lead terminal 212 and the cathode lead terminal 222 may each be connected to the connection surface in an L-shape. Alternatively, the anode lead terminal 212 and the cathode lead terminal 222 may each be bent after being connected to the connection surface.

[0066] Because the anode lead portion 111a contains valve metal, a relatively stable native oxide film is formed on its surface. Therefore, connecting the anode lead terminal 212 to the anode lead portion 111a is relatively difficult. In contrast, connecting the anode lead terminal 212 to the anode connecting member 211 can be done easily and reliably. Of course, when connecting the anode lead terminal 212 to the anode connecting member 211, the anode lead terminal 212 may also be connected to the anode lead portion 111a. These descriptions also apply to the connections on the cathode portion 130 side.

[0067] As described above, a solid electrolytic capacitor 10 is obtained. In the solid electrolytic capacitor 10, the connection surface 211a of the anode connection member 211 is covered by the anode lead terminal 212, but is exposed from the outer casing 140. Similarly, the connection surface 221a of the cathode connection member 221 is covered by the cathode lead terminal 222, but is exposed from the outer casing 140.

[0068] In the example described above, an example was explained in which the cathode connecting member 221 is also cut. However, the cathode connecting member 221 does not need to be cut. In that case, the cathode connecting member is not cut and is used as the cathode lead terminal 231. An example of the solid electrolytic capacitor 10 in that case is schematically shown in Figure 4.

[0069] In the above manufacturing method, the anode connecting member 211 may be sandwiched between the ends of a plurality of stacked anode lead portions 111a, and the cathode connecting member 221 may be sandwiched between a plurality of stacked cathode portions 130. Figure 5A schematically shows the state after the completion of step (i) in such a case. Figure 5B schematically shows the final solid electrolytic capacitor 10. As shown in Figures 5A and 5B, the anode connecting member 211 is sandwiched between a plurality of stacked anode lead portions 111a. The cathode connecting member 221 is sandwiched between a plurality of stacked cathode portions 130.

[0070] (Embodiment 2) Embodiment 2 describes a manufacturing method for another example of a solid electrolytic capacitor including a solid electrolytic capacitor element. In Embodiment 2, the anode body of the solid electrolytic capacitor element is a sintered body. The solid electrolytic capacitor of Embodiment 2 contains one solid electrolytic capacitor element.

[0071] First, as shown in Figure 6A, one solid electrolytic capacitor element 100 is connected to the anode connecting member 211 and the cathode-side lead terminal 231 (step (i)). In Embodiment 2, an example in which only the anode connecting member 211 side is cut is described, but similar to Embodiment 1, the cathode connecting member may also be connected to the solid electrolytic capacitor element 100, and both the anode connecting member 211 side and the cathode connecting member side may be cut. In that case, as described above, the cathode lead terminal is connected to the connection surface of the cathode connecting member that is exposed by the cutting.

[0072] Figure 7 schematically shows a cross-sectional view of an example of a solid electrolytic capacitor element 100. The solid electrolytic capacitor element 100 includes an anode portion 110 which includes an anode body (sintered body) 111 and an anode lead portion (anode wire) 111a, a dielectric layer 120 which covers at least a part of the anode body 111, and a cathode portion 130 which covers at least a part of the dielectric layer 120. The cathode portion 130 includes an electrolyte layer 131 which covers at least a part of the dielectric layer 120, and a conductive layer 132 which is formed on the electrolyte layer 131.

[0073] The conductive layer 132 is connected to the cathode-side lead terminals 231 by a metal paste or the like. One end of the anode lead portion 111a is embedded in the anode body 111. The other end of the anode lead portion 111a is connected to the anode connecting member 211 by welding or the like.

[0074] Next, steps (ii) to (iv) are carried out in the same manner as in Embodiment 1, except that the cathode connecting member side is not cut. In this way, the solid electrolytic capacitor 10 shown in Figure 6B is obtained.

[0075] (Note) The following technologies are disclosed as described above. (Technology 1) A method for manufacturing a solid electrolytic capacitor, comprising at least one solid electrolytic capacitor element including a cathode portion and an anode portion including an anode lead portion, Step (i) of connecting one anode connecting member made of a metal other than valve metal to the anode lead portion of the at least one solid electrolytic capacitor element, (ii) A step of forming an outer casing so as to cover the at least one solid electrolytic capacitor element and at least a part of the anode connecting member, (iii) A step of removing a part of the outer casing to expose a part of the surface of the anode connecting member as a connecting surface from the outer casing, A method for manufacturing a solid electrolytic capacitor, comprising the step (iv) of connecting the anode lead terminal to the connection surface of the anode connecting member. (Technology 2) The solid electrolytic capacitor includes a plurality of stacked solid electrolytic capacitor elements, The manufacturing method according to Technology 1, wherein in step (i), the ends of the anode lead portions of a plurality of solid electrolytic capacitor elements are connected together to the anode connecting member. (Technology 3) The manufacturing method according to Art 1 or 2, wherein the anode portion includes a sintered body containing valve metal. (Technology 4) The manufacturing method according to any one of the technologies 1 to 3, wherein step (iii) includes step (iii-a) of removing the part of the exterior by cutting the exterior and the anode connecting member together. (Technology 5) The manufacturing method according to Technical 4, wherein step (iii) further includes step (iii-b), after step (iii-a), removing the portion of the outer casing exposed at the cut surface, thereby causing the portion of the anode connecting member to protrude from the outer casing. (Technology 6) The above step (i) further includes the step of connecting a cathode connecting member made of a metal other than valve metal to the cathode portion, In step (ii) above, the outer casing is formed so as to cover the at least one solid electrolytic capacitor element, at least a portion of the anode connecting member, and at least a portion of the cathode connecting member. The above step (iii) further includes the step of removing another part of the outer casing to expose the surface of a part of the cathode connecting member as a connecting surface from the outer casing, The manufacturing method according to any one of the technologies 1 to 5, wherein step (iv) further includes the step of connecting the cathode lead terminal to the connection surface of the cathode connecting member. (Technology 7) It is a solid electrolytic capacitor, At least one solid electrolytic capacitor element, A single anode connecting member made of a metal other than valve metal, The at least one solid electrolytic capacitor element and the outer casing arranged to cover the anode connecting member, Including the anode lead terminals that are exposed to the outside, The solid electrolytic capacitor element includes a cathode portion and an anode portion including an anode lead portion. The anode connecting member is connected to the anode lead-out section, A portion of the surface of the anode connecting member is exposed from the outer casing as a connecting surface. A solid electrolytic capacitor in which the connection surface of the anode connecting member and the anode lead terminal are connected. (Technology 8) It includes a plurality of stacked solid electrolytic capacitor elements, The solid electrolytic capacitor according to Technical Reference 7, wherein the ends of the multiple anode lead portions of the multiple solid electrolytic capacitor elements are grouped together and connected to the anode connecting member. (Technology 9) The anode portion comprises a sintered body containing valve metal, as described in Art 7 or 8, for the solid electrolytic capacitor. (Technology 10) A solid electrolytic capacitor according to any one of technologies 7 to 9, wherein a portion of the anode connecting member protrudes from the outer casing. (Technology 11) The present invention further includes a cathode connecting member made of a metal other than valve metal that is covered by the aforementioned outer casing, and a cathode lead terminal exposed to the outside, The cathode connecting member is connected to the cathode portion, A portion of the surface of the cathode connecting member is exposed from the outer casing as a connecting surface. A solid electrolytic capacitor according to any one of the technologies 7 to 10, wherein the connection surface of the cathode connecting member and the cathode lead terminal are connected. [Industrial applicability]

[0076] This disclosure can be used in solid electrolytic capacitors. Although the present invention has been described in relation to preferred embodiments at present, such disclosure should not be interpreted restrictively. Various modifications and alterations will undoubtedly become apparent to those skilled in the art in the field to which the invention pertains by reading the above disclosure. Accordingly, the appended claims should be interpreted as encompassing all modifications and alterations without departing from the true spirit and scope of the invention. [Explanation of symbols]

[0077] 10: Solid electrolytic capacitor 100: Solid electrolytic capacitor element 110: Anode section 111: Anode 111a: Anode extraction section 130: Cathode part 140: Exterior 211: Anode connection member 211a: Connection surface 212: Anode lead terminal 221: Cathode connection member 221a: Connection surface 222: Cathode lead terminal 231: Lead terminal

Claims

1. A method for manufacturing a solid electrolytic capacitor, comprising at least one solid electrolytic capacitor element including a cathode portion and an anode portion including an anode lead portion, Step (i) of connecting one anode connecting member made of a metal other than valve metal to the anode lead portion of the at least one solid electrolytic capacitor element, (ii) A step of forming an outer casing so as to cover the at least one solid electrolytic capacitor element and at least a part of the anode connecting member, (iii) a step of removing a part of the outer casing to expose a part of the surface of the anode connecting member as a connecting surface from the outer casing, The process includes (iv) connecting the anode lead terminal and the connection surface of the anode connecting member, The solid electrolytic capacitor includes a plurality of stacked solid electrolytic capacitor elements, A method for manufacturing a solid electrolytic capacitor, wherein in step (i) above, the anode connecting member is connected to the anode lead portion while the ends of the anode lead portions of each of the multiple solid electrolytic capacitor elements are in direct contact with each other.

2. A method for manufacturing a solid electrolytic capacitor, comprising at least one solid electrolytic capacitor element including a cathode portion and an anode portion including an anode lead portion, Step (i) of connecting one anode connecting member made of a metal other than valve metal to the anode lead portion of the at least one solid electrolytic capacitor element, (ii) A step of forming an outer casing so as to cover the at least one solid electrolytic capacitor element and at least a part of the anode connecting member, (iii) a step of removing a part of the outer casing to expose a part of the surface of the anode connecting member as a connecting surface from the outer casing, The process includes (iv) connecting the anode lead terminal and the connection surface of the anode connecting member, The solid electrolytic capacitor includes a plurality of stacked solid electrolytic capacitor elements, A method for manufacturing a solid electrolytic capacitor, wherein in step (i) above, the ends of the anode leads of each of the multiple solid electrolytic capacitor elements are integrated by welding.

3. A method for manufacturing a solid electrolytic capacitor, comprising at least one solid electrolytic capacitor element including a cathode portion and an anode portion including an anode lead portion, Step (i) of connecting one anode connecting member made of a metal other than valve metal to the anode lead portion of the at least one solid electrolytic capacitor element, (ii) A step of forming an outer casing so as to cover the at least one solid electrolytic capacitor element and at least a part of the anode connecting member, (iii) a step of removing a part of the outer casing to expose a part of the surface of the anode connecting member as a connecting surface from the outer casing, The process includes (iv) connecting the anode lead terminal and the connection surface of the anode connecting member, A method for manufacturing a solid electrolytic capacitor, wherein in step (i), the anode connecting member, which is arranged to surround the anode lead portion, is connected to the anode lead portion.

4. The solid electrolytic capacitor includes a plurality of stacked solid electrolytic capacitor elements, The manufacturing method according to claim 3, wherein in step (i), the ends of the anode lead portions of a plurality of solid electrolytic capacitor elements are connected together to the anode connecting member.

5. The manufacturing method according to any one of claims 1 to 4, wherein the anode portion includes a sintered body containing valve metal.

6. The manufacturing method according to any one of claims 1 to 4, wherein step (iii) includes step (iii-a) of removing the outer casing by cutting the outer casing and the anode connecting member together.

7. The manufacturing method according to claim 6, wherein step (iii) further includes step (iii-b), after step (iii-a), removing the portion of the outer casing exposed at the cut surface, thereby causing the portion of the anode connecting member to protrude from the outer casing.

8. The above step (i) further includes the step of connecting a cathode connecting member made of a metal other than valve metal to the cathode portion, In step (ii) above, the outer casing is formed so as to cover the at least one solid electrolytic capacitor element, at least a portion of the anode connecting member, and at least a portion of the cathode connecting member. The above step (iii) further includes the step of removing another part of the outer casing to expose the surface of a part of the cathode connecting member as a connecting surface from the outer casing, The manufacturing method according to any one of claims 1 to 4, wherein step (iv) further comprises connecting the cathode lead terminal to the connection surface of the cathode connecting member.

9. It is a solid electrolytic capacitor, Multiple stacked solid electrolytic capacitor elements, A single anode connecting member made of a metal other than valve metal, An outer casing arranged to cover the plurality of solid electrolytic capacitor elements and the anode connecting member, Including the anode lead terminals that are exposed to the outside, The solid electrolytic capacitor element includes a cathode portion and an anode portion including an anode lead portion. The anode connecting member is connected to the anode lead-out section, A portion of the surface of the anode connecting member is exposed from the outer casing as a connecting surface. The connection surface of the anode connecting member and the anode lead terminal are connected. The ends of the anode leads of each of the plurality of solid electrolytic capacitor elements are in direct contact with each other. A solid electrolytic capacitor in which the ends of multiple anode lead-out portions are collectively connected to the anode connecting member.

10. It is a solid electrolytic capacitor, Multiple stacked solid electrolytic capacitor elements, A single anode connecting member made of a metal other than valve metal, An outer casing arranged to cover the plurality of solid electrolytic capacitor elements and the anode connecting member, Including the anode lead terminals that are exposed to the outside, The solid electrolytic capacitor element includes a cathode portion and an anode portion including an anode lead portion. The anode connecting member is connected to the anode lead-out section, A portion of the surface of the anode connecting member is exposed from the outer casing as a connecting surface. The connection surface of the anode connecting member and the anode lead terminal are connected. The ends of the anode leads of each of the aforementioned multiple solid electrolytic capacitor elements are welded together to form a single unit. A solid electrolytic capacitor in which the ends of the integrated anode lead-out portions are collectively connected to the anode connecting member.

11. It is a solid electrolytic capacitor, At least one solid electrolytic capacitor element, A single anode connecting member made of a metal other than valve metal, An outer casing arranged to cover the at least one solid electrolytic capacitor element and the anode connecting member, Including the anode lead terminals that are exposed to the outside, The solid electrolytic capacitor element includes a cathode portion and an anode portion including an anode lead portion. The anode connecting member is connected to the anode lead-out section, A portion of the surface of the anode connecting member is exposed from the outer casing as a connecting surface. The connection surface of the anode connecting member and the anode lead terminal are connected. The anode connecting member includes a portion that surrounds the anode lead portion and is connected to the anode lead portion, in a solid electrolytic capacitor.

12. It includes a plurality of stacked solid electrolytic capacitor elements, The solid electrolytic capacitor according to claim 11, wherein the ends of the multiple anode lead portions of the multiple solid electrolytic capacitor elements are grouped together and connected to the anode connecting member.

13. The anode portion comprises a sintered body containing valve metal, as described in any one of claims 9 to 12, for the solid electrolytic capacitor.

14. The solid electrolytic capacitor according to any one of claims 9 to 12, wherein a portion of the anode connecting member protrudes from the outer casing.

15. The present invention further includes a cathode connecting member made of a metal other than valve metal that is covered by the aforementioned outer casing, and a cathode lead terminal exposed to the outside, The cathode connecting member is connected to the cathode portion, A portion of the surface of the cathode connecting member is exposed from the outer casing as a connecting surface. The solid electrolytic capacitor according to any one of claims 9 to 12, wherein the connection surface of the cathode connecting member and the cathode lead terminal are connected.

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