Electrolytic capacitor and method for manufacturing same

Abstract

This electrolytic capacitor comprises a capacitor element, a bottomed case that accommodates the capacitor element, a sealing member that seals an opening of the bottomed case, and an external terminal that penetrates the sealing member. The capacitor element is provided with a wound body, and a solid electrolyte that is bonded to the wound body. The wound body is provided with a tab lead that is drawn from an end surface of the wound body and is connected to the external terminal. The tab lead has, at the position where the tab lead is drawn from the end surface of the wound body, a first portion that is bent toward the inner-peripheral side of the wound body and extends in a first direction.

Description

Electrolytic capacitor and its manufacturing method

[0001] The present disclosure relates to electrolytic capacitors and methods for manufacturing the same.

[0002] Patent Document 1 proposes "a method for manufacturing an electrolytic capacitor having a first electrode and a second electrode, comprising: a first connecting step of connecting a foil-shaped first internal lead to a first electrode foil; a second connecting step of connecting a rod-shaped first external lead to the first internal lead after the first connecting step to obtain the first electrode; a first inserting step of inserting the first external lead into an insertion opening of a sealing plate after the second connecting step; an accommodating step of accommodating the first electrode and the second electrode in a container after the first inserting step; and a sealing step of closing the opening of the container with the sealing plate after the accommodating step."

[0003] International Publication No. 2021 / 172440

[0004] One aspect of the present disclosure relates to an electrolytic capacitor. The electrolytic capacitor includes a capacitor element, a bottomed case that houses the capacitor element, a sealing member that seals an opening of the bottomed case, and an external terminal that penetrates the sealing member. The capacitor element includes a wound body and a solid electrolyte adhered to the wound body. The wound body includes a tab lead that extends from an end face of the wound body and is connected to the external terminal. The tab lead is bent toward the inner periphery of the wound body at a position where it extends from the end face of the wound body, and has a first portion that extends in a first direction.

[0005] Another aspect of the present disclosure relates to a method for manufacturing an electrolytic capacitor, the method including the steps of: (i) preparing a wound body having a tab lead extending from an end face; (ii) connecting an external terminal to the tab lead; (iii) attaching a solid electrolyte to the wound body to obtain a capacitor element; (iv) after attaching the solid electrolyte to the wound body, bending the tab lead toward the inner periphery of the wound body at a position where the tab lead extends from the end face of the wound body to form a first portion extending in a first direction; and (v) housing the capacitor element in a bottomed case and sealing an opening of the bottomed case with a sealing member through which the external terminal passes.

[0006] According to the present disclosure, it is possible to suppress short circuits between tab leads of an electrolytic capacitor.

[0007] 1 is a flowchart showing an example of a manufacturing method of an electrolytic capacitor. FIG. 1 is a plan view schematically showing a first electrode and a second electrode after a tab lead connecting step. FIG. 2 is a perspective view schematically showing an example of a wound body. FIG. 3 is a side view illustrating a part of an external terminal connecting step. FIG. 4 is a side view illustrating a part of a solid electrolyte adhering step to the wound body. FIG. 5 is a perspective view illustrating a part of an external terminal connecting step. FIG. 6 is a side view illustrating a wound body after a step of forming a first portion and a second portion on the tab lead. FIG. 7 is a side view illustrating a wound body after a step of attaching a sealing member to an external terminal. FIG. 8 is a side view showing an electrolytic capacitor after a sealing step, with a bottomed case and a sealing member in cross section. FIG. 9 is a perspective view schematically showing a wound body of an electrolytic capacitor of a second embodiment. FIG. 10 is a perspective view schematically showing a wound body of an electrolytic capacitor of a third embodiment. FIG. 11 is a cross-sectional view including two external terminals of the electrolytic capacitor of the third embodiment, taken along a plane parallel to the winding axis. FIG. 12 is a cross-sectional view including a tab lead extending along an end face of the wound body of the electrolytic capacitor of the third embodiment, taken along a plane parallel to the winding axis. FIG. 13 is an external view of an example of an electrolytic capacitor.

[0008] Patent Document 1 states that "from the viewpoint of ease of handling, the step of adhering the conductive polymer is preferably performed on the laminate integrated with the sealing plate after the first and second insertion steps" (see paragraph 0029 and FIG. 7 of Patent Document 1). At this time, the internal leads are implanted from the end faces of the electrode foils, but because the internal leads are bent, the solid electrolyte may creep up onto the lead portions and adhere excessively, causing a short circuit between the leads.

[0009] The following describes embodiments of the electrolytic capacitor according to the present disclosure using examples, but the present disclosure is not limited to the examples described below. In the following description, specific numerical values ​​and materials may be used as examples. However, other numerical values ​​and materials may be used as long as the effects of the present disclosure are obtained. In this specification, the term "numerical value A to numerical value B" includes numerical value A and numerical value B and can be interpreted as "numerical value A or greater and numerical value B or less." In the following description, when lower and upper limits for specific physical properties or conditions are exemplified, any of the exemplified lower limits and any of the exemplified upper limits can be arbitrarily combined, as long as the lower limit is not greater than the upper limit. When multiple materials are exemplified, one of the materials may be selected and used alone, or two or more materials may be used in combination.

[0010] The present disclosure also encompasses combinations of two or more features arbitrarily selected from the appended claims, i.e., two or more features arbitrarily selected from the appended claims can be combined unless a technical contradiction arises.

[0011] The term "electrolytic capacitor" may be interpreted as a "solid electrolytic capacitor" or a "solid-liquid hybrid electrolytic capacitor." The "conductive polymer" forms at least a part of the solid electrolyte layer.

[0012] An electrolytic capacitor according to an embodiment of the present disclosure includes a capacitor element, a bottomed case that houses the capacitor element, a sealing member that seals the opening of the bottomed case, and an external terminal that penetrates the sealing member.

[0013] The capacitor element includes a wound body and a solid electrolyte attached to the wound body. The wound body includes a tab lead extending from an end face of the wound body and connected to an external terminal. The tab lead has a first portion that bends toward the inner periphery of the wound body at a position where the tab lead extends from the end face of the wound body and extends in a first direction. In one aspect, the first direction is a direction approaching the external terminal. The tab lead may correspond to the internal lead of Patent Document 1, and the external terminal may correspond to the external lead of Patent Document 1.

[0014] The wound body includes, for example, a first electrode and a second electrode having different polarities. One of the first electrode and the second electrode may be an anode member having a dielectric coating formed on its surface, and the other may be a cathode member. If the first electrode is an anode member (cathode member), the second electrode is a cathode member (anode member).

[0015] At least a portion of the dielectric coating is covered with a solid electrolyte. That is, the anode member and the cathode member are wound with the solid electrolyte interposed therebetween. A separator may be disposed between the anode member and the cathode member. The separator may be, for example, a known separator used in the field of electrolytic capacitors.

[0016] The first electrode and the second electrode each have a first tab lead and a second tab lead extending from an end face of the winding body, and the first tab lead is connected to the first external terminal, and the second tab lead is connected to the second external terminal.

[0017] That is, the electrolytic capacitor has at least one pair of tab leads (first and second tab leads) with opposite polarities, and at least one pair of external terminals (first and second external terminals) with opposite polarities.

[0018] The number of each tab lead and each external terminal is not limited to one. The number of first tab leads may be two or more, the number of second tab leads may be two or more, the number of first external terminals may be two or more, and the number of second external terminals may be two or more.

[0019] In this specification, descriptions relating to "tab lead" or "external terminal" may apply to the first tab lead and the second tab lead, respectively, and may apply to the first external terminal and the second external terminal, respectively.

[0020] In the electrolytic capacitor described above, after the solid electrolyte is applied to the wound body, the tab lead is bent at a position where it exits from the end face of the wound body to form the first portion. However, as in Patent Document 1, if "the step of applying the conductive polymer is performed on the laminate integrated with the sealing plate after the first and second insertion steps," it is difficult to bend the tab lead to form the first portion. This is because the closer the tab lead is to the end face of the wound body, the more solid electrolyte creeps up the tab lead, making it more likely to cause a short circuit between the leads.

[0021] On the other hand, when the tab lead is bent from the leading-out position on the end face of the winding body toward the inner periphery of the winding body, the position of the center of gravity of the entire tab lead is closer to the center of the external terminal and the winding body than when the tab lead is bent toward the outer periphery of the winding body as in Patent Document 1. As a result, for example, when vibration is applied to the electrolytic capacitor, the load applied to the connection between the external terminal and the tab lead is reduced. This stabilizes the connection between the tab lead and the external terminal, making it less likely for the resistance of the connection to increase, which is advantageous for reducing ESR.

[0022] Furthermore, if the tab lead is bent inward from the lead-out position on the end face of the winding body and not bent any further, the length of the tab lead becomes significantly shorter. The shorter the tab lead, the lower the resistance, which is even more advantageous in reducing ESR.

[0023] In an electrolytic capacitor according to another embodiment, the tab lead may further include a second portion bent in the opposite direction at a tip of the first portion in the first direction of extension of the first portion and facing the first portion. The second portion may be folded onto the first portion. In this case, the external terminal is connected to the second portion of the tab lead. That is, the connection portion between the tab lead and the external terminal is formed in the second portion. Therefore, the first portion is interposed between the connection portion between the tab lead and the external terminal and the end face of the winding body. Note that there may or may not be a fold at the boundary between the first portion and the second portion.

[0024] With this structure, for example, when vibration is applied to the electrolytic capacitor, the connection portion between the tab lead and the external terminal does not directly collide with the end face of the winding body, but rather the impact is absorbed by the first portion of the tab lead before colliding with the end face. This reduces the impact on the connection portion, further stabilizing the connection state between the tab lead and the external terminal. Furthermore, since the impact on the winding body is also reduced, deterioration of the winding body is suppressed, which is also advantageous in suppressing an increase in ESR.

[0025] When the tab lead has a second portion, the distance from the position where the tab lead is led out from the end face of the winding body to the boundary between the first and second portions is greater than the distance from the connection portion of the external terminal to the boundary. Therefore, the center of gravity of the connection portion is closer to the inner periphery of the winding body. As a result, for example, when vibration is applied to an electrolytic capacitor, the connection portion is less susceptible to the vibration of the winding body. This further stabilizes the connection state between the tab lead and the external terminal. In other words, the resistance of the connection portion is less likely to increase, which is advantageous for stabilizing the ESR. Note that, in one aspect, the "boundary between the first and second portions" of the tab lead can refer to the "portion with the greatest curvature" of the tab lead.

[0026] The tab lead may be coated with a solid electrolyte, so it is desirable to form an oxide film on the surface of the tab lead. The oxide film prevents electrical conduction between the tab lead and the solid electrolyte.

[0027] From the viewpoint of sufficiently suppressing internal short circuits, it is desirable that the solid electrolyte does not adhere to 50% or more of the surface area of ​​the portion of the tab lead interposed between the external terminal and the end face of the winding body.

[0028] In order to sufficiently prevent internal short circuits, it is desirable that no solid electrolyte be attached to the connection between the tab lead and the external terminal.

[0029] Furthermore, from the viewpoint of sufficiently suppressing internal short circuits, if the tab lead has a second portion, it is desirable that the solid electrolyte not be attached to 90% or more of the surface area of ​​the second portion.

[0030] In addition, from the viewpoint of sufficiently suppressing internal short circuits, it is desirable that no solid electrolyte be present between the second portion and the first portion.

[0031] Two or more tab leads having the same polarity may be overlapped at the connection portion and connected to an external terminal, i.e., at least one of the anode member and the cathode member may have a multi-tab structure to which two or more tab leads are connected.

[0032] When two or more tab leads having the same polarity are overlapped at a connection portion and connected to an external terminal, at least one of the two or more overlapping tab leads may have the first portion and not the second portion, or all of the two or more overlapping tab leads may have the first portion and not the second portion. In this case, the length of the tab lead can be shortened and the current collection ability is improved because there are two or more tab leads, resulting in a very small ESR.

[0033] When two or more tab leads having the same polarity are overlapped at a connection portion and connected to an external terminal, at least one of the two or more overlapping tab leads may have a first portion and a second portion. All of the two or more overlapping tab leads may have a first portion and a second portion. In this case, the connection state between the tab leads and the external terminal is further stabilized and the impact on the winding body is reduced, which is advantageous for stabilizing ESR. In addition, the presence of two or more tab leads improves current collection.

[0034] The electrolytic capacitor may further include a liquid component. That is, the electrolytic capacitor may be a solid-liquid hybrid electrolytic capacitor (also simply referred to as a "hybrid electrolytic capacitor"). In this case, at least a portion of the first portion may be in contact with the liquid component. The first portion is a portion to which the solid electrolyte is relatively likely to adhere. Therefore, it is desirable that the first portion be in a state in which it can come into contact with the liquid component and be chemically converted. As a result, if an oxide film is formed on the surface of the first portion, repair of the oxide film on the first portion will proceed as necessary. If an oxide film is not formed on the surface of the first portion, a chemical conversion film will be formed by applying a voltage to the electrolytic capacitor.

[0035] The second portion may or may not be in contact with the liquid component, but preferably is in contact.

[0036] Next, a method for manufacturing an electrolytic capacitor according to this embodiment is an effective method for manufacturing the electrolytic capacitor, and includes the steps of: (i) preparing a wound body having tab leads extending from an end face; (ii) connecting external terminals to the tab leads; (iii) attaching a solid electrolyte to the wound body to obtain a capacitor element; (iv) after attaching the solid electrolyte to the wound body, bending the tab leads toward the inner periphery of the wound body at a position where they extend from the end face of the wound body to form a first portion extending in a first direction; and (v) housing the capacitor element in a bottomed case and sealing the opening of the bottomed case with a sealing member through which the external terminals pass.

[0037] Another method for manufacturing an electrolytic capacitor further includes a step of bending the tab lead in the opposite direction at the tip of the first portion in the first direction to form a second portion opposite to the first portion, and interposing the first portion between the connection portion between the tab lead and the external terminal and the end face of the winding body.

[0038] When bending the tab lead after attaching the solid electrolyte to the winding body, the tab lead is in a state of being embedded from the end face of the winding body when the solid electrolyte is attached to the winding body. Since the tab lead is connected to an external terminal, it has a length sufficient to allow connection to the external terminal. Therefore, it is easy to prevent the solid electrolyte from adhering to most of the portion of the tab lead that protrudes (embedded) from the end face of the winding body. Therefore, it is also easy to prevent the solid electrolyte from adhering to the connection portion between the tab lead and the external terminal.

[0039] In contrast, when the tab lead is bent toward the inner periphery of the winding body and then the solid electrolyte is applied to the winding body, it is difficult to prevent the solid electrolyte from creeping up onto the tab lead when the solid electrolyte is applied to the winding body. Therefore, it is also difficult to prevent short circuits between the tab leads via the solid electrolyte. When two or more tab leads having the same polarity are stacked at a connection portion and connected to an external terminal, the solid electrolyte is particularly likely to creep up onto the tab lead. This is thought to be because, when the winding body is immersed in a treatment liquid containing a solid electrolyte, capillary action due to surface tension causes the treatment liquid to penetrate into the gaps between the stacked tab leads.

[0040] When applying the solid electrolyte to the wound body, it is desirable that the tab lead bend as little as possible from the position where it is led out of the end face of the wound body, and stand upright. In this case, it becomes easier to immerse the entire wound body, including the end face from which the tab lead leads out, in the treatment liquid. This allows a larger amount of solid electrolyte to be applied to the wound body. At this time, an external terminal may be temporarily fixed to the tab lead, or an external terminal may be connected to the tab lead.

[0041] In step (iii) of applying a solid electrolyte to the wound body to obtain a capacitor element, the solid electrolyte does not have to be applied to 50% or more of the surface area of ​​the portion of the tab lead interposed between the external terminal and the end face of the wound body.In step (iii), the solid electrolyte does not have to be applied to the connection portion between the tab lead and the external terminal.

[0042] When the second portion is formed on the tab lead, the solid electrolyte need not be applied to 90% or more of the surface area of ​​the second portion in step (iii), and the solid electrolyte need not be interposed between the second portion and the first portion in step (iii) and subsequent steps.

[0043] In the step (iii) of adhering the solid electrolyte to the wound body to obtain the capacitor element, the solid electrolyte may be adhered only to the boundary between the first portion and the second portion, or to a portion of the tab lead that is closer to the wound body than the portion with the greatest curvature.

[0044] In a capacitor element, when two or more tab leads having the same polarity are overlapped at a connection portion and connected to an external terminal, the step (iv) of forming a first portion in the tab lead may be a step of forming the first portion, but not the second portion, in at least one of the two or more overlapped tab leads.

[0045] In the capacitor element, when two or more tab leads having the same polarity are overlapped at a connection portion and connected to an external terminal, the step (iv) of forming a first portion on the tab lead may be a step of forming a first portion and a second portion on at least one of the two or more overlapped tab leads.

[0046] When the external terminal is temporarily fixed to the tab lead, after the step (iii) of adhering the solid electrolyte to the wound body to obtain a capacitor element, the step (ii) of connecting the external terminal to the tab lead by pressure welding or welding may be performed. Also, when the electrolytic capacitor contains a liquid component, the tab lead may be bent to cause at least a part of the tab lead to adhere to the liquid component.

[0047] The external terminal is attached to the sealing material so as to penetrate the sealing material. The tab lead is usually foil-shaped and is joined to the external terminal by pressure welding or welding. The process of penetrating (inserting) the external terminal through the sealing material can be performed after forming the connection between the tab lead and the external terminal. This eliminates the need to consider interference between the sealing material and a jig or the like of a joining device used to connect the tab lead and the external terminal, making it easier to shorten the tab lead.

[0048] Hereinafter, an electrolytic capacitor and a manufacturing method thereof according to a first embodiment of the present disclosure will be described with reference to the drawings. However, this embodiment is not limited thereto. Hereinafter, if the first electrode is an anode member (cathode member), the second electrode is also a cathode member (anode member).

[0049] 1 is a flowchart showing an example of a method for manufacturing an electrolytic capacitor according to this embodiment. This manufacturing method includes the steps of (i) preparing a wound body, (ii) connecting external terminals to tab leads, (iii) applying a solid electrolyte to the wound body, (iv) forming a first portion on the tab lead, and (v) housing and sealing the capacitor element in a bottomed case.

[0050] Step (i) In step (i), a wound body having a tab lead extending from an end surface is prepared. Here, the wound body includes a first electrode and a second electrode having opposite polarities. One of the first electrode and the second electrode is an anode member having a dielectric coating formed on its surface, and the other of the first electrode and the second electrode is a cathode member. The first electrode and the second electrode each have a first tab lead and a second tab lead extending from the end surface of the wound body. The first tab lead is connected to a first external terminal, and the second tab lead is connected to a second external terminal. This case will be described with reference to FIGS. 2 to 9.

[0051] The step (i) includes, for example, a tab lead connecting step (S1) and a stacking and winding step (S2). In the tab lead connecting step (S1), a first electrode 11A and a second electrode 11B are prepared, and a first tab lead 15A is connected to the first electrode 11A, and a second tab lead 15B is connected to the second electrode 11B. The connection method is not particularly limited, but examples include crimping by drilling, laser welding, and resistance welding.

[0052] FIG. 2 is a plan view schematically illustrating a state in which a first electrode 11A connected to a first tab lead 15A, a second electrode 11B connected to a second tab lead 15B, and a separator 13 interposed between the first electrode 11A and the second electrode 11B are arranged in stacking order. In FIG. 2, the first electrode 11A and the second electrode 11B are shown hatched for convenience. Also, for convenience, the first lead portion 15Aa of the first tab lead 15A and the second lead portion 15Ba of the second tab lead 15B, each having a length L, are shown hatched for convenience. The first electrode 11A and the second electrode 11B are stacked so that most of them overlap. The separator 13 is disposed between the first electrode 11A and the second electrode 11B to prevent them from contacting each other. In FIG. 2, two first tab leads 15A are connected to the first electrode 11A, and two second tab leads 15B are connected to the second electrode 11B.

[0053] Thereafter, the first electrode 11A, the second electrode 11B, and the separator 13 are wound (S2). Fig. 3 is a perspective view showing a schematic example of the wound body 10. A separator 13 is also disposed on the outermost periphery of the wound body 10, and the end of the winding is secured with a stop tape 14 (see Fig. 2).

[0054] 3, the connection positions of the two first tab leads 15A to the first electrode 11A and the two second tab leads 15B to the second electrode 11B are set so that the two first lead portions 15Aa overlap each other and the two second lead portions 15Ba overlap each other on the wound body 10. Each tab lead protrudes in an upright manner from the end face of the wound body 10. In the illustrated example, the lead-out positions of the first tab leads 15A and the lead-out positions of the second tab leads 15B on the end face of the wound body 10 are arranged symmetrically with respect to the center of the wound body 10, but the lead-out positions can be changed depending on the design.

[0055] 2 and 3, the longitudinal direction of each tab lead is parallel to the winding axis direction (arrow A), but the longitudinal direction of each tab lead may be inclined with respect to the winding axis direction when connected to each electrode. Also, first tab lead 15A and second tab lead 15B may be configured so that first drawn-out portion 15Aa of first tab lead 15A and second drawn-out portion 15Ba of second tab lead 15B, which are hatched, are inclined with respect to the winding axis direction.

[0056] Step (ii) is a step of connecting external terminals to the tab leads (external terminal connecting step (S3)). Here, a case will be described in which a rod-shaped first external terminal 17A is connected to the first tab lead 15A, and a rod-shaped second external terminal 17B is connected to the second tab lead 15B.

[0057] 4, two second tab leads 15B having the same polarity are overlapped at a connection portion and connected to a second external terminal 17B. Similarly, two first tab leads 15A having the same polarity are overlapped at a connection portion and connected to a first external terminal 17A. The method of connecting the tab leads and the external terminals is not particularly limited.

[0058] 4, the second external terminal 17B may include, for example, a lead body portion 171, a protruding end portion 172 that is inserted into the sealing material 20, and a base end portion 173 that is located closer to the connection portion with the tab lead than the protruding end portion 172. The base end portion 173 has a larger diameter than the insertion hole for the protruding end portion 172 that is provided in the sealing material 20. The base end portion 173 makes it easier to position the second external terminal 17B relative to the sealing material 20 and also makes it less likely that the second external terminal 17B will come off the sealing material 20. The first external terminal 17A is connected to the first tab lead 15A in a similar manner (see FIG. 7).

[0059] As shown in the illustrated example, a washer 18 may be disposed on the opposite side of the base end 173. The second connection portion 16B (see FIG. 7) of the second tab lead 15B may be sandwiched between the base end 173 and the washer 18. Similarly, the first connection portion 16A of the first tab lead 15A may be sandwiched between the base end 173 and the washer 18. The washer 18 is used as needed.

[0060] Step (iii) Step (iii) is a step of adhering a solid electrolyte to the wound body to obtain a capacitor element (step (S4) of adhering a solid electrolyte).

[0061] By applying a solid electrolyte to the wound body, at least a portion of the dielectric coating formed on the surface of the anode member is covered with the solid electrolyte. The solid electrolyte effectively functions as a cathode material. The solid electrolyte improves the capacitance of the electrolytic capacitor and reduces the interelectrode resistance between the first and second electrodes, which is advantageous for achieving a low ESR. In this specification, the wound body to which the solid electrolyte is applied is referred to as a capacitor element to distinguish it from the wound body.

[0062] A simple and preferred method for impregnating the wound body with the treatment liquid is to immerse the wound body 10 in treatment liquid L contained in a container 9, as shown in FIG. 5 . The immersion time varies depending on the size of the wound body 10, but is, for example, 1 second to 5 hours, and preferably 1 minute to 30 minutes. The impregnation is preferably carried out under reduced pressure, for example, in an atmosphere of 10 to 100 kPa, and preferably 40 to 100 kPa. Ultrasonic vibrations may be applied to the wound body 10 or the treatment liquid L while the wound body 10 is immersed in the treatment liquid. After the wound body 10 is removed from the treatment liquid L, it is dried, for example, preferably at 50 to 300°C, and more preferably at 100 to 200°C.

[0063] By impregnating the wound body 10 with the treatment liquid L, it becomes easier to supply a sufficient amount of treatment liquid L to the end face of the wound body 10 from which the tab lead is led out, while minimizing the solid electrolyte creeping up onto the tab lead.

[0064] The step of impregnating the wound body 10 with the treatment liquid L and the step of drying the wound body 10 may be repeated two or more times. By performing these steps multiple times, the coverage of the solid electrolyte layer with respect to the dielectric coating can be increased.

[0065] In this manner, a capacitor element can be obtained in which a solid electrolyte containing a conductive polymer is interposed between first electrode 11A and second electrode 11B.

[0066] The solid electrolyte preferably contains a conductive polymer. For example, a π-conjugated polymer may be used as the conductive polymer. The solid electrolyte may contain a π-conjugated polymer and a dopant.

[0067] Examples of π-conjugated polymers that can be used include polypyrrole, polythiophene, polyfuran, polyaniline, and derivatives thereof. Derivatives refer to polymers having polypyrrole, polythiophene, polyfuran, polyaniline, or the like as a basic skeleton. For example, polythiophene derivatives include poly(3,4-ethylenedioxythiophene) (PEDOT). These may be used alone or in combination of two or more types, or may be copolymers of two or more types of monomers.

[0068] The weight average molecular weight of the conductive polymer is not particularly limited, but is, for example, 1,000 to 100,000.

[0069] From the viewpoint of suppressing dedoping of the dopant from the conductive polymer, it is desirable that the solid electrolyte contain a polymer dopant. Examples of polymer dopants include anions of polyvinyl sulfonic acid, polystyrene sulfonic acid, polyallylsulfonic acid, polyacrylic sulfonic acid, polymethacrylic sulfonic acid, poly(2-acrylamido-2-methylpropanesulfonic acid), polyisoprene sulfonic acid, and polyacrylic acid. These may be used alone or in combination of two or more. Furthermore, these may be homopolymers or copolymers of two or more monomers. Among these, polystyrene sulfonic acid (PSS) is preferred.

[0070] The weight average molecular weight of the polymer dopant is not particularly limited, but is preferably, for example, 1,000 to 500,000 in terms of facilitating the formation of a homogeneous solid electrolyte layer.

[0071] The treatment liquid L may be a solution in which a conductive polymer is dissolved in a solvent, or a dispersion in which a conductive polymer is dispersed in a solvent (dispersion medium).

[0072] The concentration of the conductive polymer contained in the treatment liquid L is preferably, for example, 0.5 to 10 mass %. The average particle size D50 of the conductive polymer is preferably, for example, 0.01 to 0.5 μm. Here, the average particle size D50 is the median diameter in a volumetric particle size distribution determined by a particle size distribution measuring device using a dynamic light scattering method. Treatment liquid L with such a concentration is suitable for forming a solid electrolyte layer of appropriate thickness and is easily impregnated into the dielectric layer.

[0073] Next, the solvent is evaporated from the conductive polymer adhered to the dielectric layer by drying, thereby forming a solid electrolyte containing the conductive polymer so as to cover at least a portion of the dielectric layer.

[0074] The treatment liquid L can be obtained, for example, by dispersing a conductive polymer in a solvent, or by polymerizing a precursor monomer in a solvent to generate conductive polymer particles. A preferred treatment liquid is, for example, poly(3,4-ethylenedioxythiophene) (PEDOT) doped with polystyrene sulfonic acid (PSS), i.e., PEDOT / PSS.

[0075] The solvent may be water, a mixture of water and a non-aqueous solvent, or a non-aqueous solvent. The non-aqueous solvent is not particularly limited, but for example, a protic solvent or an aprotic solvent can be used. In consideration of stable dispersibility of the conductive polymer, the solvent may contain 50 mass % or more of water.

[0076] FIG. 6 is a perspective view schematically illustrating a process of connecting external terminals (second external terminals 17B) to tab leads (second tab leads 15B). A through hole 15a is formed at one end of each tab lead. Lead body portions 171 of the second external terminals 17B are inserted into the through holes 15a of the two second tab leads 15B. At this time, the second tab lead 15B extends in the winding axis direction (arrow A), and the second external terminals 17B extend in a direction intersecting the winding axis direction (arrow B). In this state, the connection portion of the second tab lead 15B is pressed from both main surfaces to crush the end of the second external terminal 17B on the washer 18 side. This locks and connects the second external terminal 17B to the second tab lead 15B. Similarly, the first external terminal 17A is locked and connected to the first tab lead 15A. At this time, the first tab lead 15A extends in the winding axis direction (arrow A), and the first external terminal 17A extends in a direction (arrow B) intersecting the first direction.

[0077] Step (iv) After the solid electrolyte is applied to the wound body and the connection of each external terminal to each tab lead is completed, in step (iv), as shown in FIG. 7, each tab lead is bent toward the inner periphery of the wound body at a position where it is led out from the end face of the wound body 10, thereby forming a first portion (S5).

[0078] After the tab leads and external terminals are connected, the external terminals extending in the direction of arrow B are rotated so that they extend in the winding axis direction (arrow A). At this time, first tab lead 15A and second tab lead 15B are each bent to form a first portion and a second portion.

[0079] 7, the first tab lead 15A bends from a lead-out position on the end face of the winding body 10 toward the inner periphery of the winding body 10, extends in a direction approaching the center of the winding body 10 (first direction), and then bends in the opposite direction to the first direction to form a first portion 15Ax and a second portion 15Ay. The second tab lead 15B bends from a lead-out position on the end face of the winding body 10 toward the inner periphery of the winding body 10, extends in a direction approaching the center of the winding body 10 (first direction), and then bends in the opposite direction to the first direction to form a first portion 15Bx and a second portion 15By. Therefore, the connection portion 16A between the first tab lead 15A and the first external terminal 17A faces the end face of the winding body 10 via the first portion 15Ax. Furthermore, the connection portion 16B between the second tab lead 15B and the second external terminal 17B faces the end face of the wound body 10 via the first portion 15Bx. With this configuration, the overall center of gravity of each tab lead and each connection portion is closer to the center of the wound body, and as a result, when vibration is applied to the electrolytic capacitor, for example, the load applied to the connection portion between the external terminal and the tab lead is reduced.

[0080] Step (v) Step (v) is a step in which the tip of the external terminal connected to the tab lead is inserted into the insertion hole of the sealing material 20, and then the capacitor element is accommodated in the bottomed case 60 (accommodating step (S6)), and the opening of the bottomed case 60 is sealed with the sealing material 20 through which the external terminal passes (sealing step (S8)).

[0081] Before the capacitor element is housed in the bottomed case 60, the protruding ends of the external terminals connected to each tab lead may be inserted into the insertion holes of the sealing member 20. This integrates the wound body 10 and the sealing member 20. If the sealing member 20 includes a rubber member, the protruding ends of the external terminals may be press-fitted into the rubber member.

[0082] 8 is a side view that schematically shows the wound body 10 after the external terminals have been inserted into the insertion holes of the sealing member 20. At this time, each external terminal is locked to the sealing member 20 by its protruding end 172. Each external terminal is positioned by its base end 173. In this way, the wound body 10 and the sealing member 20 are integrated.

[0083] The wound body 10 integrated with the sealing material 20 is housed in a bottomed case 60. The first tab lead 15A and the second tab lead 15B are bent, but the drawn-out portions 15Aa and 15Ba are short, and there is little interference between the first external terminal 17A and the second external terminal 17B.

[0084] Thereafter, if necessary, the wound body may be impregnated with a liquid component (liquid component impregnation step (S7)). The impregnation step is performed, for example, after the wound body is housed in a bottomed case. The liquid component improves the self-repairing performance of the dielectric coating. Furthermore, since the liquid component essentially functions as a cathode material, it is expected to have the effect of increasing the electrostatic capacitance. The impregnation method is not particularly limited.

[0085] Finally, the wound body 10 is sealed with the bottomed case 60 and the sealing member 20. In this way, the electrolytic capacitor 100 is completed.

[0086] FIG. 9 is a cross-sectional view showing a schematic example of a completed electrolytic capacitor.

[0087] After the electrolytic capacitor 100 is completed, an aging treatment may be performed while applying a rated voltage to the electrolytic capacitor.

[0088] When the sealing member 20 includes a rubber material, the sealing member 20 may be placed on the open end of the bottomed case 60, and the open end of the bottomed case 60 may be bent inward. The sealing member 20, which includes a rubber material, is crimped by the open end without being damaged. This fixes the sealing member 20 to the bottomed case 60 and seals the bottomed case 60. Furthermore, the bottomed case 60 may be recessed inward to compress the sealing member 20. For example, an annular groove may be formed on the inner surface of the bottomed case 60 in a portion facing the sealing member 20. This reduces the diameter of the sealing member 20, thereby preventing the sealing member 20 from coming off even when the internal pressure increases.

[0089] Second Embodiment Fig. 10 shows an example of a capacitor element in an electrolytic capacitor according to a second embodiment. Fig. 10 shows the outer shape of the wound body, tab leads, and external terminals, but the details of the wound body are omitted because they are the same as those of the first embodiment.

[0090] In the wound body 10A of the second embodiment, the first tab lead 15A and the second tab lead 15B are not led out from positions symmetrical with respect to the center of the wound body 10A. The central angle formed by the lead-out positions of the first tab lead 15A and the second tab lead 15B about the winding axis (the center of the wound body 10A) is approximately 90° to 130°.

[0091] Furthermore, before being bent at the lead-out position on the end face of the winding body 10, the first tab lead 15A has a first lead portion 15Aa that protrudes (is planted) so as to extend in a direction inclined with respect to the winding axis direction, and before being bent at the lead-out position on the end face of the winding body 10, the second tab lead 15B has a second lead portion 15Ba that protrudes (is planted) so as to extend in a direction inclined with respect to the winding axis direction. To make the lead portions extend in a direction inclined with respect to the winding axis direction, the tab leads may be cut out so that the lead portions are bent in advance, an unbent tab lead may be connected to an electrode in an oblique direction, or the lead portion may be folded back. With this configuration, even if the end face of the winding body 10A is small, the tab leads can be bent to form the first portion while avoiding interference between external terminals.

[0092] The first tab lead 15A and the second tab lead 15B are each bent at a lead-out position on the end face of the winding body 10, so that the first portion 15Ax of the first tab lead 15A and the first portion 15Bx of the second tab lead 15B each extend along the end face of the winding body 10A. The direction in which the first portion 15Ax extends (first direction) is generally parallel to the direction in which the first portion 15Bx extends (first direction). In other words, the angle formed between the extension direction of the first portion 15Ax and the extension direction of the first portion 15Bx is, for example, in the range of 0° to 20°.

[0093] 10, when the tab lead is bent inward from the leading-out position on the end face of the wound body 10A and not bent any further, the length of the tab lead becomes very short. The shorter the tab lead, the smaller the resistance of the tab lead, which is further advantageous in reducing ESR.

[0094] 11 shows an example of a capacitor element in an electrolytic capacitor according to a third embodiment. In FIG. 11, the outer shape of the wound body, tab leads, and external terminals are shown, and the details of the wound body are omitted because they are the same as those of the first embodiment.

[0095] In the wound body 10B of the third embodiment, the central angle formed by the lead-out position of the first tab lead 15A and the lead-out position of the second tab lead 15B, centered on the winding axis (the center of the wound body 10B), is approximately 90° to 130°.

[0096] Again, before being bent at the lead-out position on the end face of the winding body 10, first tab lead 15A has a shape in which first lead portion 15Aa of first tab lead 15A protrudes (stands up) so as to extend in a direction inclined with respect to the winding axis direction, and before being bent at the lead-out position on the end face of the winding body 10, second tab lead 15B has a shape in which second lead portion 15Ba of second tab lead 15B protrudes (stands up) so as to extend in a direction inclined with respect to the winding axis direction. By bending first tab lead 15A and second tab lead 15B at the lead-out position on the end face of the winding body 10 and then folding them back in the opposite direction, first portion 15Ax and second portion Ay are formed in first lead portion 15Aa of first tab lead 15A, and first portion 15Bx and second portion 15By are formed in second lead portion 15Ba of second tab lead 15B. The first portion 15Ax and the first portion 15Bx extend along the end surface of the wound body 10A, and the direction in which the first portion 15Ax extends (the first direction) is generally parallel to the direction in which the first portion 15Bx extends (the first direction). The second portion 15Ay extends by bending in the opposite direction from the tip of the first portion 15Ax in the first direction, and the second portion 15By extends by bending in the opposite direction from the tip of the first portion 15Bx in the first direction. This allows the first and second portions to be folded while avoiding interference between the external terminals. The angle between the extension direction of the first portion 15Ax and the second portion 15Ay and the extension direction of the first portion 15Bx and the second portion By is, for example, in the range of 0° to 20°.

[0097] The connection portion between the tab lead and the external terminal is formed in the second portion, so that the first portion of the tab lead is interposed between the connection portion and the end face of the wound body 10B.

[0098] According to the wound body 10B of the third embodiment, when vibration is applied to the electrolytic capacitor, the connection portion between the tab lead and the external terminal does not directly collide with the end face of the wound body, reducing the impact on the connection portion and further stabilizing the connection state between the tab lead and the external terminal. Furthermore, since the impact on the wound body 10B is also reduced, deterioration of the wound body is suppressed, which is also advantageous for suppressing an increase in ESR. Furthermore, as a result of the position of the center of gravity of the tab lead and the external terminal being closer to the center of the wound body 10B, when vibration is applied to the electrolytic capacitor, for example, the connection portion between the external terminal and the tab lead is less susceptible to the vibration of the wound body. Therefore, the connection state between the tab lead and the external terminal is further stabilized.

[0099] 12 to 14 show an electrolytic capacitor 100 obtained by housing the wound body 10B shown in FIG. 11 in a bottomed case 60 and sealing the opening of the bottomed case 60 with a sealing member 20 through which the first external terminal 17A and the second external terminal 17B pass. FIG. 12 is a cross-sectional view of an electrolytic capacitor including the wound body 10B, taken along a plane parallel to the winding axis, including the first external terminal 17A and the second external terminal 17B. FIG. 13 is a cross-sectional view of an electrolytic capacitor including the wound body 10B, taken along a plane parallel to the winding axis, including tab leads extending along the end faces of the wound body. FIG. 14 is an external view of an example of the electrolytic capacitor 100.

[0100] Although the above description has been given using an example of a wound electrolytic capacitor, the configuration of the electrolytic capacitor is not limited to this.

[0101] The components of the electrolytic capacitor according to this embodiment will be specifically described below, although this embodiment is not limited thereto.

[0102] (First Electrode) The first electrode functions as, for example, an anode member. In this case, the first electrode is a metal foil containing at least one valve metal such as titanium, tantalum, aluminum, or niobium. The first electrode may contain the valve metal in the form of an alloy containing the valve metal or a compound containing the valve metal. The thickness of the first electrode is not particularly limited and is, for example, 15 μm or more and 300 μm or less. The thickness is the average value at any five points (the same applies hereinafter).

[0103] The surface of the first electrode may be roughened by etching or the like. A dielectric coating may be formed on the surface of the first electrode. The dielectric coating may be formed, for example, by chemically treating the first electrode. In this case, the dielectric coating may contain an oxide of a valve metal. However, the dielectric coating is not limited to this, and may be any material that functions as a dielectric.

[0104] (Second Electrode) The second electrode functions as, for example, a cathode. The second electrode may be a metal foil. The type of metal is not particularly limited, and may be a valve metal or an alloy containing a valve metal, as with the first electrode, or may be a metal other than a valve metal such as iron (Fe) or copper (Cu). The thickness of the second electrode is not particularly limited, and is, for example, 15 μm or more and 300 μm or less.

[0105] The surface of the second electrode may be roughened or subjected to a chemical conversion treatment, if necessary. In addition, an inorganic layer containing carbon, nickel, titanium, or oxides or nitrides thereof may be formed on the surface of the second electrode.

[0106] (First and second tab leads) The tab leads are foil-shaped. Specifically, the tab leads are conductive members having a thickness of 15 μm or more and 300 μm or less. The material thereof is not particularly limited as long as it is conductive, and examples thereof include aluminum, titanium, nickel, copper, iron, tantalum, niobium, and alloys thereof.

[0107] (Separator) The separator is not particularly limited as long as it is porous. Examples of the separator include a cellulose fiber nonwoven fabric, a glass fiber nonwoven fabric, a polyolefin microporous membrane, a woven fabric, and a nonwoven fabric. The thickness of the separator is not particularly limited, and is, for example, 10 μm or more and 500 μm or less. When a conductive polymer or a solid electrolyte having a sufficient thickness is disposed between the first electrode and the second electrode, the separator may be omitted.

[0108] (First and second external terminals) The external terminals are electrically conductive members used to extend the electrodes to the outside. The external terminals may be rod-shaped and have sufficient rigidity to be inserted into the sealing material. The material for the external terminals is not particularly limited as long as it is electrically conductive, and examples thereof include aluminum, titanium, nickel, copper, iron, tantalum, niobium, and alloys thereof.

[0109] (Sealing member) The sealing member closes the opening of the bottomed case. The sealing member may be made of an insulating material. The sealing member preferably includes a rubber member. The rubber member has elasticity. Therefore, when the external terminals are inserted into the sealing member, damage to both the external terminals and the sealing member is more easily suppressed. Furthermore, even when the internal pressure increases, the rubber member deforms, suppressing cracks in the sealing member and damage to the internal leads.

[0110] The International Rubber Hardness Degrees (IRHD) of the rubber member is preferably 99 or less, more preferably 95 or less. The IRHD of the rubber member is preferably 70 or more, more preferably 80 or more. Examples of elastic polymers that constitute such rubber members include silicone rubber, fluorine-containing rubber, ethylene propylene rubber, chlorosulfonated polyethylene rubber (such as Hypalon rubber), butyl rubber, isoprene rubber, and isobutyl-isoprene rubber. Of these, fluorine-containing rubber is preferred from the viewpoint of heat resistance. One type of elastic polymer may be used alone, or two or more types may be used in combination.

[0111] The sealing member has one or more insertion holes for inserting the external terminals. The positions of the insertion holes are set appropriately depending on the positions of the external terminals. The number of insertion holes is set appropriately depending on the number of external terminals.

[0112] (Bottomed Case) The bottomed case has an opening. The bottomed case has a cylindrical portion and a bottom surface that closes one end of the cylindrical portion. The other end (open end) of the cylindrical portion is closed with a sealing member. The outer shape of the bottomed case is, for example, cylindrical or approximately cylindrical.

[0113] The material of the bottomed case is not particularly limited, and examples thereof include metals such as aluminum, aluminum alloy, stainless steel, copper, iron, brass, etc. A surface layer (e.g., an oxide layer, a resin layer, etc.) having a desired function may be formed on the outer surface of the bottomed case.

[0114] (Liquid Component) The liquid component contains a solvent. Examples of the solvent include sulfone compounds, lactone compounds, carbonate compounds, polyhydric alcohols, and the like. Examples of the sulfone compounds include sulfolane, dimethyl sulfoxide, and diethyl sulfoxide. Examples of the lactone compounds include γ-butyrolactone and γ-valerolactone. Examples of the carbonate compounds include dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), ethylene carbonate (EC), propylene carbonate (PC), and fluoroethylene carbonate (FEC). Examples of the polyhydric alcohols include glycol compounds such as ethylene glycol (EG), diethylene glycol, triethylene glycol, propylene glycol, and polyethylene glycol (PEG); glycerin, and the like. These may be used alone or in combination.

[0115] The solvent may contain a compound having two or more hydroxy groups. Examples of such compounds include polyhydric alcohols. The content of the compound having two or more hydroxy groups may be 50% by mass or more, 60% by mass or more, or 70% by mass or more of the total solvent.

[0116] The liquid component may further contain an acid component. When a conductive polymer and a dopant are attached to the electrolytic capacitor, the acid component in the liquid component suppresses the dopant dedoping phenomenon and stabilizes the conductivity of the conductive polymer. Even if the dopant is dedoped from the conductive polymer, the acid component of the liquid component re-dops the sites left by the dedoping, making it easier to maintain a low ESR. In order to enhance the effect of suppressing the dedoping phenomenon, the concentration of the acid component may be 5% by mass or more and 50% by mass or less, or 15% by mass or more and 35% by mass or less.

[0117] The liquid component may contain a base component together with an acid component. The base component neutralizes at least a portion of the acid component. Thus, corrosion of the electrode caused by the acid component can be suppressed while increasing the concentration of the acid component. From the viewpoint of effectively suppressing dedoping, it is preferable that the acid component be in excess of the base component in terms of equivalent ratio. For example, the equivalent ratio of the acid component to the base component may be 1 or more and 30 or less. The concentration of the base component contained in the liquid component may be 0.1 mass% or more and 20 mass% or less, or 3 mass% or more and 10 mass% or less.

[0118] The pH of the liquid component is preferably 4 or less, more preferably 3.8 or less, and even more preferably 3.6 or less. By adjusting the pH of the liquid component to 4 or less, deterioration of the conductive polymer is further suppressed. The pH is preferably 2.0 or more.

[0119] (Additional Note) The above description discloses the following techniques.

[0120] (Technology 1) An electrolytic capacitor comprising: a capacitor element; a bottomed case that houses the capacitor element; a sealing member that seals an opening of the bottomed case; and an external terminal that penetrates the sealing member, wherein the capacitor element comprises a wound body and a solid electrolyte adhered to the wound body, and the wound body comprises a tab lead that is led out from an end face of the wound body and connected to the external terminal, and the tab lead is bent toward the inner periphery of the wound body at a position where it is led out from the end face of the wound body, and has a first portion that extends in a first direction.

[0121] (Technology 2) The electrolytic capacitor according to Technology 1, wherein the tab lead further has a second portion bent in the opposite direction at a tip of the first portion in the first direction and facing the first portion, and the first portion is interposed between a connection portion between the tab lead and the external terminal and the end surface of the winding body.

[0122] (Technology 3) The electrolytic capacitor according to Technology 1 or 2, wherein a distance from a position where the tab lead is led out from the end surface of the winding body to a boundary between the first portion and the second portion is longer than a distance from the connection portion to the boundary.

[0123] (Technique 4) The electrolytic capacitor according to any one of claims 1 to 3, wherein an oxide film is formed on the surface of the tab lead.

[0124] (Technology 5) The electrolytic capacitor according to any one of Technologies 1 to 4, wherein the solid electrolyte is not attached to 50% or more of the surface area of ​​the portion of the tab lead interposed between the external terminal and the end face of the winding body.

[0125] (Technology 6) The electrolytic capacitor according to any one of Technologies 1 to 5, wherein the solid electrolyte is not attached to 90% or more of the surface area of ​​the second portion.

[0126] (Technology 7) The electrolytic capacitor according to any one of Technologies 1 to 6, wherein the solid electrolyte is not interposed between the first portion and the second portion.

[0127] (Technology 8) The electrolytic capacitor according to any one of Technologies 1 to 7, further comprising: two or more tab leads having the same polarity including the tab lead; the two or more tab leads being overlapped at the connection portion and connected to the external terminal; and at least one of the two or more tab leads having the first portion.

[0128] (Technology 9) The electrolytic capacitor according to any one of Technologies 1 to 8, further comprising: two or more tab leads having the same polarity including the tab lead; the two or more tab leads being overlapped at the connection portion and connected to the external terminal; and at least one of the two or more tab leads having the first portion and the second portion.

[0129] (Technology 10) The electrolytic capacitor according to any one of Technologies 1 to 9, further comprising a liquid component, wherein the first portion is in contact with the liquid component.

[0130] (Technology 11) A method for manufacturing an electrolytic capacitor, comprising: a step of preparing a wound body having a tab lead drawn out from an end face; a step of connecting an external terminal to the tab lead; a step of attaching a solid electrolyte to the wound body to obtain a capacitor element; a step of, after attaching the solid electrolyte to the wound body, bending the tab lead toward the inner periphery of the wound body at a position where it is drawn out from the end face of the wound body to form a first portion extending in a first direction; and a step of housing the capacitor element in a bottomed case and sealing an opening of the bottomed case with a sealing member through which the external terminal passes.

[0131] (Technology 12) The method for manufacturing an electrolytic capacitor according to Technology 11, further comprising the step of bending the tab lead in an opposite direction at a tip of the first portion in the first direction to form a second portion facing the first portion, and interposing the first portion between a connection portion between the tab lead and the external terminal and the end surface of the winding body.

[0132] (Technology 13) The method for manufacturing an electrolytic capacitor according to Technology 11 or 12, wherein in the step of adhering the solid electrolyte to the wound body to obtain a capacitor element, the solid electrolyte is not adhered to the connecting portion.

[0133] (Technology 14) The method for manufacturing an electrolytic capacitor according to any one of Techniques 11 to 13, wherein in the step of adhering the solid electrolyte to the wound body to obtain a capacitor element, the solid electrolyte is adhered only to a portion of the tab lead that is closer to the wound body than to a boundary between the first portion and the second portion.

[0134] (Technology 15) The method for manufacturing an electrolytic capacitor according to any one of Technologies 11 to 14, wherein the capacitor element has two or more tab leads having the same polarity including the tab lead, the two or more tab leads are overlapped at the connection portion and connected to the external terminal, and the first portion is formed in at least one of the two or more tab leads.

[0135] (Technology 16) The method for manufacturing an electrolytic capacitor according to any one of Technologies 11 to 15, wherein the capacitor element has two or more tab leads having the same polarity including the tab lead, the two or more tab leads are overlapped at the connection portion and connected to the external terminal, and the first portion and the second portion are formed in at least one of the two or more tab leads.

[0136] The present disclosure can be used in electrolytic capacitors having a solid electrolyte.

[0137] 100 Electrolytic capacitor 10, 10A, 10B Wound body 11A First electrode 11B Second electrode 13 Separator 14 Winding stop tape 15A First tab lead 15Aa First drawn portion 15Ax First portion 15Ay Second portion 15B Second tab lead 15Ba Second drawn portion 15Bx First portion 15By Second portion 15a Through hole 16A First connecting portion 16B Second connecting portion 17A First external terminal 17B Second external terminal 171 Lead body portion 172 Point end portion 173 Base end portion 18 Washer 20 Sealing member 60 Bottomed case

Claims

1. A capacitor element; a bottomed case that accommodates the capacitor element; a sealing member that seals the opening of the bottomed case; an external terminal that penetrates the sealing member; Equipped with the capacitor element includes a wound body and a solid electrolyte attached to the wound body, the winding body includes a tab lead that is led out from an end face of the winding body and connected to the external terminal, The tab lead has a first portion that is bent toward the inner periphery of the winding body at a position where it is led out from the end face of the winding body and extends in a first direction.

2. the tab lead further includes a second portion bent in the opposite direction at a tip of the first portion in the first direction and facing the first portion; 2. The electrolytic capacitor according to claim 1, wherein the first portion is interposed between a connection portion between the tab lead and the external terminal and the end surface of the wound body.

3. 3. The electrolytic capacitor according to claim 2, wherein a distance from a position where the tab lead is led out from the end face of the wound body to a boundary between the first portion and the second portion is greater than a distance from the connection portion to the boundary.

4. 3. The electrolytic capacitor according to claim 1, wherein an oxide film is formed on the surface of the tab lead.

5. 3. The electrolytic capacitor according to claim 1, wherein the solid electrolyte is not attached to 50% or more of the surface area of ​​the portion of the tab lead interposed between the external terminal and the end face of the winding body.

6. 3. The electrolytic capacitor according to claim 2, wherein the solid electrolyte is not deposited on 90% or more of the surface area of ​​the second portion.

7. The electrolytic capacitor according to claim 2 , wherein the solid electrolyte is not interposed between the first portion and the second portion.

8. two or more tab leads having the same polarity including the tab lead; the two or more tab leads are overlapped at the connection portion and connected to the external terminal, The electrolytic capacitor of claim 1 , wherein at least one of the two or more tab leads has the first portion.

9. two or more tab leads having the same polarity including the tab lead; the two or more tab leads are overlapped at the connection portion and connected to the external terminal, 3. The electrolytic capacitor of claim 2, wherein at least one of the two or more tab leads has the first portion and the second portion.

10. Further comprising a liquid component, The electrolytic capacitor of claim 1 , wherein the first portion is in contact with the liquid component.

11. preparing a wound body having tab leads drawn out from the end surface; connecting an external terminal to the tab lead; a step of depositing a solid electrolyte onto the wound body to obtain a capacitor element; a step of adhering a solid electrolyte to the winding body, and then bending the tab lead toward an inner periphery of the winding body at a position where the tab lead is led out from the end face of the winding body to form a first portion extending in a first direction; a step of housing the capacitor element in a bottomed case and sealing an opening of the bottomed case with a sealing member through which the external terminals pass; Equipped with Manufacturing method of electrolytic capacitors.

12. 12. The method for manufacturing an electrolytic capacitor according to claim 11, further comprising the step of bending the tab lead in an opposite direction at a tip of the first portion in the first direction to form a second portion opposing the first portion, and interposing the first portion between a connection portion between the tab lead and the external terminal and the end surface of the winding body.

13. 12. The method for manufacturing an electrolytic capacitor according to claim 11, wherein in the step of obtaining a capacitor element by adhering the solid electrolyte to the wound body, the solid electrolyte is not adhered to a connection portion between the tab lead and the external terminal.

14. 14. The method for manufacturing an electrolytic capacitor according to claim 13, wherein in the step of adhering the solid electrolyte to the wound body to obtain a capacitor element, the solid electrolyte is adhered only to a portion of the tab lead that is closer to the wound body than a boundary between the first portion and the second portion.

15. the capacitor element has two or more tab leads having the same polarity including the tab lead; the two or more tab leads are overlapped at connection portions between the tab leads and the external terminals and connected to the external terminals; The method for manufacturing an electrolytic capacitor according to claim 11 or 13, wherein the first portion is formed on at least one of the two or more tab leads.

16. the capacitor element has two or more tab leads having the same polarity including the tab lead; the two or more tab leads are overlapped at the connection portion and connected to the external terminal; The method for manufacturing an electrolytic capacitor according to claim 12 or 13, wherein the first portion and the second portion are formed in at least one of the two or more tab leads.