Electrolytic capacitor and method for manufacturing the same

Abstract

An electrolytic capacitor includes a capacitor element, a first current collector member, and a case. The capacitor element includes a wound body in which a first electrode foil and a second electrode foil facing each other are wound. The first current collector member is connected to the first electrode foil. The case houses the capacitor element and the first current collector member. The first electrode foil has a first facing portion facing the second electrode foil and a first non-facing portion not facing the second electrode foil. The first non-facing portion is located at a first end portion in the winding axis direction of the wound body. The first current collector member is disposed on the first end portion side of the wound body and is connected to the first non-facing portion of the first electrode foil.

Description

Technical Field

[0001] The present invention relates to an electrolytic capacitor and a method for manufacturing the same, and more particularly, to an improvement in ESR characteristics. Background Art

[0002] Capacitors used in electronic devices are required to have a large capacitance and a small equivalent series resistance (ESR) in the high-frequency region. However, in the case of using a wound body obtained by winding electrode foils as a capacitor element, the resistance tends to increase and the ESR tends to increase. Patent Document 1 teaches providing an exposed portion on the electrode foil and spraying metal on the exposed portion.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Utility Model Laid-Open No. 54-90653 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] However, in the method of Patent Document 1, the ESR is not sufficiently reduced.

[0008] Means for Solving the Problems

[0009] The electrolytic capacitor according to the first aspect of the present invention includes: a capacitor element, a first current collector, and a case that houses the capacitor element and the first current collector. The capacitor element includes a wound body in which a first electrode foil and a second electrode foil facing each other are wound, a first lead terminal connected to the first electrode foil, and a second lead terminal connected to the second electrode foil. The first current collector is connected to the first electrode foil. The first electrode foil has a first facing portion facing the second electrode foil and a first non-facing portion not facing the second electrode foil, and the first non-facing portion is located at a first end portion in the winding axis direction of the wound body. The first current collector is disposed on the first end portion side of the wound body and is connected to the first non-facing portion of the first electrode foil.

[0010] The manufacturing method of the electrolytic capacitor according to the second aspect of the present invention includes: a step of preparing a first electrode foil connected to a first lead terminal and a second electrode foil connected to a second lead terminal; a step of oppositely laminating the first electrode foil and the second electrode foil in such a manner that a first non-opposing portion that does not oppose the second electrode foil is formed on the first electrode foil; a step of winding the first electrode foil and the second electrode foil with the first non-opposing portion located at a first end portion in the winding axis direction to obtain a capacitor element; a connecting step of arranging the first current collecting member on the first end portion side of the capacitor element by connecting the first current collecting member to the first non-opposing portion; and a step of housing the capacitor element in a case.

[0011] Effects of the Invention

[0012] According to the present invention, an electrolytic capacitor with reduced ESR can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a cross-sectional view schematically showing a main part of a capacitor element according to an embodiment of the present invention.

[0014] Figure 2 It is a cross-sectional view schematically showing an example of an electrolytic capacitor according to an embodiment of the present invention.

[0015] Figure 3A It is a top view schematically showing an example of a current collecting member according to an embodiment of the present invention.

[0016] Figure 3B It is a top view schematically showing another example of a current collecting member according to an embodiment of the present invention.

[0017] Figure 3C It is a top view schematically showing still another example of a current collecting member according to an embodiment of the present invention.

[0018] Figure 3D It is a top view schematically showing still another example of a current collecting member according to an embodiment of the present invention.

[0019] Figure 4 It is a flowchart showing an example of the manufacturing method according to an embodiment of the present invention.

[0020] Figure 5 It is a perspective view schematically showing a capacitor element during the manufacturing process in the winding step according to an embodiment of the present invention.

[0021] Figure 6 It is a perspective view schematically showing a part of the capacitor element after the winding step of the manufacturing method according to an embodiment of the present invention.

[0022] Figure 7 It is a perspective view showing a capacitor element and a current collector member in a connection process of a manufacturing method according to an embodiment of the present invention. Detailed Embodiment

[0023] When a wound body obtained by winding an electrode foil as a long strip is used as a capacitor element, the moving distance of electrons tends to become long. Therefore, in the present embodiment, a current collector member other than the lead terminal is disposed at the end of the capacitor element to collect current. Since the electrode foil is wound, if the electrode foil is connected to the current collector member disposed at the end to collect current, the moving distance of charges from the electrode foil on the outer peripheral side or the inner peripheral side to the lead terminal becomes short. As a result, the resistance becomes small, and an increase in ESR is suppressed. Therefore, even when a large ripple current flows through the electrolytic capacitor, heat generation is suppressed.

[0024] Spray plating is a method of spraying molten metal particles onto an object. When spraying metal onto an electrode foil as in Patent Document 1, there is a case where a thin electrode foil moves from a specified position due to wind pressure, or metal particles enter the inside of the wound body, resulting in a short circuit. In order to prevent a short circuit, it is only necessary to increase the region where electrode foils of different polarities do not face each other. However, the cost increases, and the region that does not contribute to the capacitance increases.

[0025] [Electrolytic Capacitor]

[0026] The electrolytic capacitor of the present embodiment includes: a capacitor element, a first current collector member, and a case. The capacitor element includes a wound body in which a first electrode foil and a second electrode foil are wound, a first lead terminal connected to the first electrode foil, and a second lead terminal connected to the second electrode foil. The first current collector member is connected to the first electrode foil, and the case houses the capacitor element and the first current collector member.

[0027] The first electrode foil has a first electrode foil facing the second electrode foil and a first non-facing portion located at a first end portion in the winding axis direction of the wound body and not facing the second electrode foil. In other words, the first non-facing portion is exposed from the first end portion side of the wound body. The first current collector member is disposed on the first end portion side and is connected to the first electrode foil at the first non-facing portion. The first end portion is a substantially circular end face of the wound body viewed from the winding axis direction.

[0028] The electrolytic capacitor may include a second current collector member connected to the second electrode foil. The second electrode foil has a second electrode foil facing the first electrode foil, and a second non-facing portion located at a second end opposite to the above-mentioned first end and not facing the first electrode foil. In other words, the second non-facing portion is exposed from the second end side of the wound body. The second current collector member is disposed on the second end side thereof and is connected to the second electrode foil at the second non-facing portion.

[0029] (Capacitor element)

[0030] The capacitor element includes a wound body in which a first electrode foil and a second electrode foil are wound, a first lead terminal connected to the first electrode foil, and a second lead terminal connected to the second electrode foil.

[0031] The first electrode foil may be an anode foil. The first electrode foil may also be a cathode foil. Among them, considering that the effect of reducing ESR is easily improved, the first electrode foil is preferably a cathode foil.

[0032] The second electrode foil shows a polarity opposite to that of the first electrode foil. When the first electrode foil is a cathode foil, the second electrode foil is an anode foil. Considering that the effect of further reducing ESR is easily improved, it is preferable to include a current collector member connected to both the anode foil and the cathode foil.

[0033] (Anode foil)

[0034] The anode foil is a metal foil containing at least one valve metal such as titanium, tantalum, aluminum, and niobium. The anode foil 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 anode foil is not particularly limited. For example, it is 15 μm or more and 300 μm or less. The thickness is the average value of any 5 points (the same hereinafter). The surface of the anode foil can be roughened by etching or the like.

[0035] A dielectric layer is formed on the surface of the anode foil. The dielectric layer is formed, for example, by subjecting the anode foil to a chemical conversion treatment. In this case, the dielectric layer may contain an oxide of the valve metal. It should be noted that the dielectric layer is not limited thereto, as long as it is a layer that functions as a dielectric.

[0036] (Cathode foil)

[0037] The cathode foil only needs to have the function of a cathode and is not particularly limited. The cathode foil can be a metal foil. The type of metal is not particularly limited and can be a valve-acting metal or an alloy containing a valve-acting metal, similar to the anode foil, or can be a metal other than a valve-acting metal such as iron (Fe) or copper (Cu). The thickness of the cathode foil is not particularly limited and is, for example, 15 μm or more and 300 μm or less. The surface of the cathode foil can be roughened as needed or can be subjected to a chemical conversion treatment. Additionally, an inorganic layer containing carbon, nickel, titanium, and their oxides or nitrides, etc. can be formed on the surface of the cathode foil.

[0038] (First current collector member)

[0039] The first current collector member is, for example, a metal plate or a metal foil. The type of metal is not particularly limited, but it is preferably a metal containing the same metal as the first electrode foil to which it is connected. For example, when the first electrode foil is an anode foil, the first current collector member is preferably a metal plate or a metal foil containing at least one valve-acting metal. When the first electrode foil is a cathode foil, the first current collector member may or may not contain a valve-acting metal.

[0040] The shape of the first current collector member is not particularly limited. From the perspective of space saving, it is preferable that the first current collector member is a plate-like object that covers at least a part of the first end portion of the wound body. Among them, it is preferable that the first current collector member has a shape that connects multiple portions at different distances from the center of the wound body in the first non-opposing portion. By connecting the first non-opposing portion in the radial direction of the wound body with the first current collector member, the moving distance of the charge on the more outer peripheral side to the first lead terminal becomes further shorter.

[0041] Generally, considering the moving distances of the charges at the outermost periphery and the innermost periphery of the electrode foil respectively, the connection position of the electrode foil and the lead terminal is set near the center in the direction (winding direction) that intersects the winding axis direction of the electrode foil. As in this embodiment, when the first current collector member connects the first non-opposing portion in the radial direction of the wound body, the moving distance of the charge at the outermost periphery or the innermost periphery becomes shorter. Therefore, the connection position of the lead terminal is not easily restricted, and the degree of freedom in design is improved.

[0042] From the aspect that it is easier to improve the charge collection property of the outermost periphery of the first electrode foil, it is preferable that, when viewed from the normal direction of the first end portion, the first current collector member covers at least a part of the region that includes at least a part of the first straight line drawn along the radial direction of the first end portion from the center of the first lead terminal toward the outer edge of the first end portion. By connecting the portion near the outermost periphery of the first non-opposing portion and the portion near the connection portion of the first lead terminal of the first non-opposing portion with the first current collector member, the moving distance of the charge at the outermost periphery of the first electrode foil to the first lead terminal becomes shorter.

[0043] Such a first current collector member has, for example, the following shapes: a disk shape having a diameter substantially the same as that of the first end portion, an annular shape having an outer diameter substantially the same as the diameter of the first end portion and an inner diameter greater than the distance from the center of the first end portion to the first lead terminal, a rectangular shape including the above-mentioned first straight line, a combination of the above-mentioned annular shape and the above-mentioned rectangular shape, and the like.

[0044] From the aspect that it is easier to improve the charge collecting property of the innermost circumference of the first electrode foil, it is preferable that, when viewed from the normal direction of the first end portion, the first current collector member covers at least a part of the region including a second straight line connecting the center of the first end portion and the center of the first lead terminal. By connecting the part near the innermost circumference of the first non-opposing portion and the part near the connection portion of the first lead terminal of the first non-opposing portion with the first current collector member, the moving distance of the charge located at the innermost circumference of the first electrode foil to the first lead terminal becomes shorter.

[0045] Such a first current collector member has, for example, the following shapes: a disk shape having a diameter substantially the same as the distance from the center of the first end portion to the first lead terminal, a rectangular shape including the above-mentioned second straight line, and the like.

[0046] From the aspect that it is easy to improve the charge collecting property of both the outermost circumference and the innermost circumference of the first electrode foil, the first current collector member may have the following shapes: a disk shape having a diameter substantially the same as that of the first end portion, a rectangular shape including at least a part of a straight line preferably drawn from the center of the first end portion through the center of the first lead terminal to the outer edge of the first end portion, a combination of a plurality of the above-mentioned rectangular shapes, a combination of the above-mentioned rectangular shape and an annular shape having an outer diameter substantially the same as the diameter of the first end portion and an inner diameter greater than the distance from the center of the first end portion to the first lead terminal, and the like.

[0047] The first current collector member may have an opening for at least one of the first lead terminal and the second lead terminal to pass through. The first current collector member may have at least one of a plurality of through holes and cuts. Thereby, the wound body is easily impregnated with the electrolytic solution and / or the conductive polymer dispersion. Examples of the first current collector member having a plurality of through holes include a metal porous body, a metal mesh, a perforated metal, an expanded metal, and the like. The thickness of the first current collector member is not particularly limited, for example, it is 15 μm or more and 300 μm or less.

[0048] Preferably, a dielectric layer is formed on the surface of the first current collector member. Thereby, corrosion of the first current collector member is easily suppressed.

[0049] The first current collector member may be attached with a conductive polymer. The conductive polymer is interposed, for example, as a solid electrolyte of an electrolytic capacitor, between the first electrode foil and the second electrode foil. Since the conductive polymer is also attached to the first current collector member, the conductivity between the first current collector member and the electrode foil is improved, and thus a further reduction in ESR can be expected.

[0050] (First lead terminal)

[0051] The material of the first lead terminal is not particularly limited as long as it is electrochemically and chemically stable and conductive, and it may be a metal or a non-metal. Its shape is also not particularly limited. The first lead terminal extends from the first end portion or the second end portion of the wound body toward the outside of the wound body.

[0052] (Second current collector member)

[0053] The shape, material, etc. of the second current collector member are the same as those of the first current collector member.

[0054] The second current collector member also preferably connects a plurality of portions at different positions from the center of the wound body in the second non-opposing portion to each other. Preferably, when viewed from the normal direction of the second end portion, the second current collector member covers at least a region including a straight line drawn along the radial direction of the second end portion from the center of the second lead terminal toward the outer edge of the second end portion. In addition, preferably, when viewed from the normal direction of the second end portion, the second current collector member covers at least a region including a straight line connecting the center of the second end portion and the center of the second lead terminal.

[0055] A dielectric layer may be formed on the surface of the second current collector member, or a conductive polymer may be attached thereto.

[0056] (Second lead terminal)

[0057] The material of the second lead terminal is the same as that of the first lead terminal. As long as it is chemically and chemically stable and conductive, it is not particularly limited and may be a metal or a non-metal. Its shape is also not particularly limited. The second lead terminal extends from the same side as the side where the first lead terminal extends of the wound body toward the outside of the wound body.

[0058] (Spacer)

[0059] A spacer may be interposed between the anode foil and the cathode foil. When a conductive polymer with a sufficient thickness is disposed between the anode foil and the cathode foil, the spacer may be omitted.

[0060] The spacer is not particularly limited as long as it is porous. Examples of the spacer include non-woven fabrics made of cellulose fibers, non-woven fabrics made of glass fibers, microporous membranes made of polyolefins, fabrics, non-woven fabrics, etc. The thickness of the spacer is not particularly limited, for example, it is 10 μm or more and 300 μm or less.

[0061] (Conductive polymer)

[0062] The conductive polymer functions as a solid electrolyte in the electrolytic capacitor.

[0063] Examples of the conductive polymer include polypyrrole, polythiophene, polyfuran, polyaniline, polyacetylene, polyphenylene, polyphenylenevinylene, polyacene, polythiophenylene vinylene, etc. These can be used alone, or two or more of them can be used in combination, and they can also be copolymers of two or more monomers.

[0064] It should be noted that in this specification, polypyrrole, polythiophene, polyfuran, polyaniline, etc. respectively refer to polymers with polypyrrole, polythiophene, polyfuran, polyaniline, etc. as the basic skeletons. Therefore, polypyrrole, polythiophene, polyfuran, polyaniline, etc. can also include their respective derivatives. For example, poly(3,4-ethylenedioxythiophene) is included in polythiophene.

[0065] The conductive polymer can be included in the electrolytic capacitor together with a dopant. The dopant can be a monomolecular anion or a polymeric anion. Specific examples of the monomolecular anion include p-toluenesulfonic acid, naphthalenesulfonic acid, etc. Specific examples of the polymeric anion include polyvinylsulfonic acid, polystyrenesulfonic acid, polyallylsulfonic acid, polypropylenesulfonic acid, polymethacrylic acid, poly(2-acrylamido-2-methylpropanesulfonic acid), polyisoprenesulfonic acid, polyacrylic acid, etc. These can be used alone, or two or more of them can be used in combination. In addition, these can be polymers of individual monomers or copolymers of two or more monomers. Among them, polymeric anions derived from polystyrenesulfonic acid are preferred.

[0066] (Case)

[0067] The case is bottomed and houses the above capacitor element, the first current collector, and the second current collector configured as needed.

[0068] The capacitor element is housed in such a manner that the first end or the second end faces the bottom of the bottomed case. At this time, the bottom of the bottomed case can be brought into contact with the current collector. Thereby, the heat dissipation performance is improved. However, when the current collector disposed on the bottom side of the bottomed case is connected to the anode foil, it is preferable to insulate between the bottom and the current collector through a spacer (electrolytic paper) or the like.

[0069] As materials for the bottomed case, metals such as aluminum, stainless steel, copper, iron, brass, or their alloys can be cited.

[0070] Figure 1 FIG. is a cross-sectional view schematically showing the main part of the capacitor element of the present embodiment. In Figure 1 the first electrode foil is an anode foil, and the second electrode foil is a cathode foil. In addition, for convenience, the anode foil, the spacer, and the cathode foil are shown with a gap therebetween, and the anode foil, the spacer, and the cathode foil near the center are omitted. Further, the non-opposing portions of each electrode foil are hatched.

[0071] The capacitor element includes a wound body 10 formed by winding an anode foil 11 (first electrode foil) and a cathode foil 12 (second electrode foil) with a spacer 13 interposed therebetween, a first lead terminal 15A connected to the anode foil 11, and a second lead terminal 15B connected to the cathode foil 12.

[0072] The anode foil 11 has a first non-opposing portion 11a that does not oppose the cathode foil 12 at a first end portion 10X in the winding axis direction A of the wound body 10. A first current collecting member 21 is disposed on the first end portion 10X side. The first current collecting member 21 is a plate-like member that covers at least a part of the first end portion 10X and has openings through which the first lead terminal 15A and the second lead terminal 15B pass.

[0073] The first current collecting member 21 is connected to the anode foil 11 at the first non-opposing portion 11a. The first current collecting member 21 connects a plurality of portions of the first non-opposing portion 11a that are at different distances from the center of the wound body 10, that is, a portion of the first non-opposing portion 11a on the outer peripheral side and a portion of the first non-opposing portion 11a on the inner peripheral side closer thereto. Specifically, the first current collecting member 21 connects a portion of the first non-opposing portion 11a near the outermost periphery and a portion of the first non-opposing portion 11a near the connection portion with the first lead terminal 15A.

[0074] The cathode foil 12 has a second non-opposing portion 12a that does not oppose the anode foil 11 at a second end portion 10Y in the winding axis direction A of the wound body 10. A second current collecting member 22 is disposed on the second end portion 10Y side. The second current collecting member 22 is connected to the cathode foil 12 at the second non-opposing portion 12a. The second current collecting member 22 connects a plurality of portions of the second non-opposing portion 12a that are at different distances from the center of the wound body 10, that is, a portion of the second non-opposing portion 12a on the outer peripheral side and a portion of the second non-opposing portion 12a on the inner peripheral side closer thereto. Specifically, the second current collecting member 22 connects a portion of the second non-opposing portion 12a near the outermost periphery and a portion of the second non-opposing portion 12a near the connection portion with the second lead terminal 15B.

[0075] A dielectric layer (not shown) is formed on the surfaces of the anode foil 11 and the first current collector member 21. A conductive polymer (not shown) is attached between the anode foil 11 and the cathode foil 12, on the surface of the first current collector member 21, and on the surface of the second current collector member 22.

[0076] Figure 2 FIG. is a cross-sectional view schematically showing an example of the electrolytic capacitor of the present embodiment.

[0077] The electrolytic capacitor 100 includes, for example, a wound body 10, a first lead terminal 15A, a second lead terminal 15B, a first current collector member 21 connected to the anode foil, a second current collector member 22 connected to the cathode foil, a bottomed case 60 that houses them, a sealing member 30 that closes the opening of the bottomed case 60, a seat plate 40 that covers the sealing member 30, and external leads 50A, 50B that are led out from the sealing member 30 and penetrate the seat plate 40.

[0078] The first lead terminal 15A connects the external lead 50A to the anode foil. The second lead terminal 15B connects the external lead 50B to the cathode foil. The second current collector member 22 connected to the cathode foil contacts the bottom of the bottomed case 60. The opening end of the bottomed case 60 is subjected to a deep drawing process inward, and the opening end is curled so as to be riveted to the sealing member 30.

[0079] Figures 3A to 3D FIG. is a top view schematically showing an example of the current collector member (first current collector member and / or second current collector member) of the present embodiment. Figures 3A to 3D The current collector members are all plate-like.

[0080] In Figure 3A In, the current collector member 20A is a disk shape that covers the entire one end of the wound body. Among them, the current collector member 20A has four cutouts 20a. Therefore, the impregnation property of the conductive polymer dispersion liquid and / or the electrolytic solution is not easily reduced. The current collector member 20A can connect a part of the non-opposing portion of the outermost periphery of one electrode foil to one lead terminal, and a part of the non-opposing portion of the innermost periphery of the electrode foil to the lead terminal, respectively. Therefore, the moving distance of the charges located on the outer peripheral side and the inner peripheral side of the electrode foil to the lead terminal becomes shorter. The current collector member 20A is disposed, for example, on the bottom side of the bottomed case. Since the current collector member 20A can contact the bottom with a large contact area, the heat dissipation property is easily improved.

[0081] In Figure 3BIn [the structure], the current collector member 20B has an annular shape with an outer diameter approximately the same as the diameter of one end of the wound body and an inner diameter greater than the distance from the center C of the end to one lead terminal. The current collector member 20B can connect a part of the non-opposing portion of the outermost periphery of the electrode foil to a part of the non-opposing portion near the lead terminal. Therefore, the moving distance of the charge on the outer peripheral side of the electrode foil to the lead terminal becomes shorter. The current collector member 20B can be disposed on the bottom side of the bottomed case or on the side opposite to the bottom.

[0082] In Figure 3C [the structure], the current collector member 20C includes Figure 3B an annular portion and a rectangular portion extending in its radial direction as shown. The rectangular portion includes a straight line extending from the center C of one end of the wound body toward the outer edge and along the radial direction of the end. Therefore, the moving distances of the charge on the outer peripheral side and the charge on the inner peripheral side of the electrode foil to the lead terminal become shorter. In the current collector member 20C, since the portion other than the annular portion and the rectangular portion is open, the lead terminal and the other lead terminal can penetrate therethrough. Therefore, the current collector member 20C is disposed, for example, on the side opposite to the bottom of the bottomed case.

[0083] In Figure 3D [the structure], the current collector member 20D includes Figure 3C an annular portion and a rectangular portion as shown. However, the rectangular portion includes a straight line drawn from the center C of one end of the wound body through the centers of both lead terminals to the outer edge of the end. Therefore, the moving distances of the charge on the outer peripheral side and the charge on the inner peripheral side of the electrode foil to the lead terminal become further shorter. The current collector member 20D is disposed, for example, on the bottom side of the bottomed case.

[0084] [Manufacturing method of electrolytic capacitor]

[0085] The electrolytic capacitor of the present embodiment can be manufactured by the following method. The present embodiment includes a manufacturing method of an electrolytic capacitor.

[0086] The manufacturing method of the electrolytic capacitor of the present embodiment includes: a step of preparing a first electrode foil connected to a first lead terminal and a second electrode foil connected to a second lead terminal; a step of oppositely laminating the first electrode foil and the second electrode foil so that a first non-opposing portion that does not oppose the second electrode foil is formed on the first electrode foil; a step of winding the first electrode foil and the second electrode foil with the first non-opposing portion located at the first end in the winding axis direction to obtain a capacitor element; a connecting step of disposing the first current collector member on the first end side of the capacitor element by connecting the first current collector member to the first non-opposing portion; and a step of housing the capacitor element in a case.

[0087] Figure 4This is a flowchart showing an example of a method for manufacturing an electrolytic capacitor according to the present embodiment.

[0088] (1) Winding process (S1)

[0089] The first electrode foil and the second electrode foil are laminated and wound to produce a capacitor element.

[0090] Before the winding process, the first lead terminal is connected to the first electrode foil in advance. Similarly, the second lead terminal is connected to the second electrode foil in advance. The connection between the electrode foil and the lead terminal is performed by welding such as laser welding, for example. The connection positions of the respective lead terminals are not particularly limited and can be appropriately set in consideration of the length in the winding direction of the electrode foil and the like. A dielectric layer is formed on the surface of the electrode foil corresponding to the anode foil.

[0091] After the first electrode foil and the second electrode foil are opposed to each other in such a manner that a first non-opposed portion that does not oppose the second electrode foil is formed at an end in the winding direction of the first electrode foil, winding is performed. As a result, the first non-opposed portion is exposed from the first end side in the winding axis direction of the wound body.

[0092] The size, shape, etc. of the first non-opposed portion are not particularly limited and can be appropriately set in consideration of the size, shape, etc. of the first current collector member. The length L1a of the first non-opposed portion in the short side direction (winding axis direction) of the first electrode foil can be, for example, 10% or more of the length L1 of the short side direction of the first electrode foil, and can also be 25% or more. In addition, the length L1a can be 50% or less of the length L1, can also be 40% or less, and can further be 30% or less. The length L1a is the average length of any three portions of the first non-opposed portion in the first electrode foil.

[0093] The first non-opposed portion can be formed over the entire length of the end of the first electrode foil in the winding direction, or can be formed on a part of the above-mentioned end. In the latter case, the first non-opposed portion is formed to extend from one or more portions of the above-mentioned end toward the first end side.

[0094] The first electrode foil and the second electrode foil can also be wound in such a manner that a second non-opposed portion is formed in addition to the first non-opposed portion. In this case, the second non-opposed portion is exposed from the second end side of the wound body.

[0095] The size of the second non - opposed portion only needs to be the same as that of the first non - opposed portion. That is, the length L2a of the second non - opposed portion in the short - side direction (winding - axis direction) of the second electrode foil can be, for example, 10% or more of the length L2 of the short - side direction of the second electrode foil, and can also be 25% or more. In addition, the length L2a can be 50% or less of the length L2, can also be 40% or less, and can further be 30% or less. The length L2a is the average length of any three portions of the second non - opposed portion in the second electrode foil.

[0096] The shape of the second non - opposed portion only needs to be the same as that of the first non - opposed portion. That is, the second non - opposed portion can be formed over the entire length of the end portion of the second electrode foil along the winding direction, or can be formed on a part of the above - mentioned end portion.

[0097] A spacer can also be interposed between the first electrode foil and the second electrode foil. In this case, the outermost layer of the wound body is, for example, the spacer. After winding, the end portion of the spacer is fixed with a stop - winding tape.

[0098] Figure 5 It is a perspective view schematically showing a capacitor element during the manufacturing process in the winding step. For convenience, the first non - opposed portion and the second non - opposed portion are shaded.

[0099] The anode foil 11 and the cathode foil 12 are laminated in such a way that the first non - opposed portion 11a is formed over the entire length of the end portion of the anode foil 11 along the winding direction B, and the second non - opposed portion 12a is formed over the entire length of the end portion of the cathode foil 12 along the winding direction B. A spacer 13 is interposed between the anode foil 11 and the cathode foil 12. The outermost periphery of the wound body 10 is the spacer 13, and the end portion of the spacer 13 is fixed with a stop - winding tape 14.

[0100] Figure 6 It is a perspective view schematically showing a part of the capacitor element after the winding step. For convenience, the lead terminals and the spacer are omitted.

[0101] On the side of the first end portion 10X of the anode foil 11, the first non - opposed portion 11a of the anode foil 11 is exposed from the cathode foil 12. On the side of the second end portion 10Y of the cathode foil 12, the second non - opposed portion 12a of the cathode foil 12 is exposed from the anode foil 11. The length L1a of the first non - opposed portion 11a of the anode foil 11 in the short - side direction is preferably 10% or more and 30% or less of the length L1 of the short - side direction of the anode foil 11. The length L2a of the second non - opposed portion 12a of the cathode foil 12 in the short - side direction is preferably 10% or more and 30% or less of the length L2 of the short - side direction of the cathode foil 12.

[0102] (2) Connection process (S2)

[0103] Connect the first current collector member to the first non-opposing portion. At this time, the first current collector member is disposed on the first end side.

[0104] In the case where the second non-opposing portion is formed, in this process, connect the second current collector member to the second non-opposing portion and dispose the second current collector member on the second end side.

[0105] The connection between the electrode foil and the current collector member is performed by welding such as laser welding, for example. The laser is irradiated radially from the side of the current collector member opposite to the wound body to a plurality of portions, for example.

[0106] Figure 7 A perspective view schematically showing the capacitor element and the current collector member in the connection process.

[0107] Place the first current collector member 21 on the first end 10X and weld it to the first non-opposing portion 11a. Place the second current collector member 22 on the second end 10Y and weld it to the second non-opposing portion 12a. The first current collector member 21 has Figure 3C the shape as shown, and the first lead terminal 15A and the second lead terminal 15B respectively penetrate through 2 openings. The second current collector member 22 has Figure 3A the shape as shown, and 4 cuts 20a are formed.

[0108] (3) Formation process of dielectric layer (S3)

[0109] After the connection process, a formation process of forming a dielectric layer on the first current collector member can be performed. Thereby, corrosion of the first current collector member can be easily suppressed. In addition, a dielectric layer can be formed again on the anode foil.

[0110] The method of forming the dielectric layer is not particularly limited and can be formed by performing a chemical conversion treatment on the first current collector member. In the chemical conversion treatment, for example, the capacitor element is immersed in a chemical conversion solution such as ammonium adipate solution, ammonium phosphate, ammonium borate, etc., and heat treatment is performed. Alternatively, the capacitor element can be immersed in the chemical conversion solution and a voltage can be applied.

[0111] (4) Conductive polymer attachment process (S4)

[0112] After the formation process of the dielectric layer, a conductive polymer can be attached to the capacitor element as needed.

[0113] A conductive polymer can be attached to a capacitor element by chemically polymerizing and / or electrochemically polymerizing raw material monomers in the presence of the capacitor element. A conductive polymer dispersion or solution containing a conductive polymer and a dispersion medium can be infiltrated into the capacitor element to attach the conductive polymer to the capacitor element. When the conductive polymer is attached by infiltrating the conductive polymer dispersion or solution into the capacitor element, residues such as oxidants during polymerization can be reduced, and thus it is easy to suppress corrosion of each current collector member and the joint portion between each current collector member and the electrode foil.

[0114] The conductive polymer is interposed between the first electrode foil and the second electrode foil, and is also attached to the first current collector member and then to the second current collector member. Thereby, the conductivity between each current collector member and the electrode foil is improved, and thus a further reduction in ESR can be expected.

[0115] (Conductive polymer dispersion)

[0116] The conductive polymer dispersion contains a conductive polymer and a dispersion medium. The conductive polymer dispersion may further contain the above-mentioned dopant.

[0117] The conductive polymer is dispersed in the dispersion medium, for example, in the form of particles. The average particle diameter of the particles of the conductive polymer is not particularly limited and can be appropriately adjusted according to polymerization conditions, dispersion conditions, etc. For example, the average particle diameter of the particles of the conductive polymer can be 0.01 μm or more and 0.5 μm or less. Here, the average particle diameter is the median particle diameter in the volume particle size distribution measured by a particle size measuring device based on the dynamic light scattering method.

[0118] The dispersion medium is not particularly limited and can be water, a non-aqueous solvent, or a mixture thereof. The non-aqueous solvent refers to the general term for liquids other than water and includes organic solvents and ionic liquids. Among them, from the viewpoints of handleability and dispersibility of the conductive polymer, the dispersion medium can be water. Water can account for 50% by mass or more of the dispersion medium, 70% by mass or more, or 90% by mass or more. Examples of the non-aqueous solvent used together with water include polar solvents (protic solvents and / or aprotic solvents).

[0119] Examples of protic solvents include alcohols such as methanol, ethanol, propanol, butanol, ethylene glycol (EG), propylene glycol, polyethylene glycol (PEG), diethylene glycol monobutyl ether, glycerol, 1-propanol, butanol, polyglycerol, sorbitol, mannitol, pentaerythritol, and formaldehyde. Examples of aprotic solvents include amides such as N-methylacetamide, N,N-dimethylformamide, N-methyl-2-pyrrolidone; esters such as methyl acetate, γ-butyrolactone (γBL); ketones such as methyl ethyl ketone; ethers such as 1,4-dioxane; sulfur-containing compounds such as dimethyl sulfoxide, sulfolane (SL); and carbonate compounds such as propylene carbonate.

[0120] A conductive polymer dispersion can be obtained, for example, by a method of dispersing particles of a conductive polymer in a dispersion medium, or a method of polymerizing a precursor monomer of a conductive polymer in a dispersion medium to form particles of a conductive polymer in the dispersion medium.

[0121] The weight-average molecular weight of the conductive polymer can be, for example, 1000 or more and 200000 or less, or can be 75000 or more and 150000 or less.

[0122] In the conductive polymer dispersion, the content of the conductive polymer can be, for example, 0.5% by mass or more and less than 3% by mass. The viscosity of the conductive polymer dispersion measured at room temperature (20 °C) using a vibrating viscometer is preferably less than 100 mPa·s.

[0123] (5) Electrolyte impregnation step (S5)

[0124] After the dielectric layer formation step, the electrolyte can be impregnated into the capacitor element as needed. The electrolyte can be impregnated without performing the above-described first impregnation step, or can be further impregnated after the first impregnation step. The self-healing performance of the dielectric layer can be easily improved by the electrolyte. In addition, since the electrolyte functions as a substantial cathode material, an effect of increasing the electrostatic capacitance can be expected. The impregnation method is not particularly limited.

[0125] (Electrolyte)

[0126] The electrolyte contains a solvent.

[0127] As the solvent, sulfone compounds, lactone compounds, carbonate compounds, polyhydric alcohols, etc. can be cited. As sulfone compounds, sulfolane, dimethyl sulfoxide, diethyl sulfoxide, etc. can be cited. As lactone compounds, γ-butyrolactone, γ-valerolactone, etc. can be cited. As carbonate compounds, dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), ethylene carbonate (EC), propylene carbonate (PC), fluoroethylene carbonate (FEC), etc. can be cited. As polyhydric alcohols, glycol compounds such as ethylene glycol (EG), diethylene glycol, triethylene glycol, propylene glycol, and polyethylene glycol (PEG); glycerol, etc. can be cited. These can be used alone or in combination of multiple kinds.

[0128] Among them, the solvent can contain compounds having two or more hydroxyl groups. As such compounds, for example, polyhydric alcohols can be cited. The content of the compound having two or more hydroxyl groups can be 50% by mass or more of all the solvents, or can be 60% by mass or more, or can also be 70% by mass or more.

[0129] The electrolytic solution can further contain an acid component. In the case where the conductive polymer and the dopant adhere to the electrolytic capacitor, the acid component in the electrolytic solution suppresses the dedoping phenomenon of the dopant and stabilizes the conductivity of the conductive polymer. In addition, even when the dopant is dedoped from the conductive polymer, the acid component of the electrolytic solution is redoped to the site of the dedoping trace, so it is easy to maintain a low ESR.

[0130] It is desirable that the acid component in the electrolytic solution does not excessively increase the viscosity of the electrolytic solution and generates anions that are easily dissociated in the electrolytic solution and easily move in the solvent. As such an acid component, for example, aliphatic sulfonic acids having 1 to 30 carbon atoms and aromatic sulfonic acids having 6 to 30 carbon atoms can be cited. Among aliphatic sulfonic acids, monobasic saturated aliphatic sulfonic acids (e.g., hexane sulfonic acid) are preferred. Among aromatic sulfonic acids, aromatic sulfonic acids having a hydroxyl group or a carboxyl group in addition to the sulfonic group are preferred. Specifically, oxyaromatic sulfonic acids (e.g., phenol-2-sulfonic acid) and sulfonated aromatic carboxylic acids (e.g., p-sulfobenzoic acid, 3-sulfophthalic acid, 5-sulfosalicylic acid) are preferred.

[0131] As other acid components, carboxylic acids can be cited. The carboxylic acid preferably contains aromatic carboxylic acids (aromatic dicarboxylic acids) having two or more carboxyl groups. As aromatic carboxylic acids, for example, phthalic acid (ortho-isomer), isophthalic acid (meta-isomer), terephthalic acid (para-isomer), maleic acid, benzoic acid, salicylic acid, trimellitic acid, pyromellitic acid can be cited. Among them, aromatic dicarboxylic acids such as phthalic acid (ortho-isomer) and maleic acid are more preferred. The carboxyl groups of aromatic dicarboxylic acids are stable and not prone to side reactions. Therefore, the effect of stabilizing the conductive polymer is manifested in the long term, which is beneficial to the long life of the electrolytic capacitor. In addition, the carboxylic acid can also be an aliphatic carboxylic acid such as adipic acid.

[0132] From the aspect of thermal stability, the acid component may include a composite compound of an organic acid and an inorganic acid. As the composite compound of an organic acid and an inorganic acid, boron disalicylate, boron dioxalate, boron diglycolate, etc. with high heat resistance can be cited.

[0133] The acid component may also include inorganic acids such as boric acid, phosphoric acid, phosphorous acid, hypophosphorous acid, and phosphonic acid.

[0134] From the aspect of improving the effect of suppressing the de-doping phenomenon, the concentration of the acid component may be 5% by mass or more and 50% by mass or less, or may be 15% by mass or more and 35% by mass or less.

[0135] The electrolytic solution may include an alkali component together with the acid component. By the alkali component, at least a part of the acid component is neutralized. Therefore, the concentration of the acid component can be increased, and the corrosion of the electrode caused by the acid component can be suppressed. From the viewpoint of effectively suppressing de-doping, the acid component is preferably in excess compared with the alkali component in terms of equivalent ratio. For example, the equivalent ratio of the acid component to the alkali component may be 1 or more and 30 or less. The concentration of the alkali component contained in the electrolytic solution may be 0.1% by mass or more and 20% by mass or less, or may be 3% by mass or more and 10% by mass or less.

[0136] The alkali component is not particularly limited. As the alkali component, for example, ammonia, primary amine, secondary amine, tertiary amine, quaternary ammonium compound, and amidine compound can be cited. As each amine, aliphatic amine, aromatic amine, heterocyclic amine, etc. can be cited.

[0137] The pH of the electrolytic solution is preferably 4 or less, more preferably 3.8 or less, and further preferably 3.6 or less. By making the pH of the electrolytic solution 4 or less, the deterioration of the conductive polymer is further suppressed. The pH is preferably 2.0 or more.

[0138] (6) Sealing process (S6)

[0139] The fabricated capacitor element is housed in a bottomed case. At this time, the first end or the second end of the capacitor element is opposed to the bottom of the bottomed case. When a current collecting member is disposed on the bottom side of the bottomed case, the bottom may be brought into contact with the current collecting member as needed.

[0140] Then, deep drawing is performed on the vicinity of the open end of the bottomed case, and the open end is riveted to the sealing member and crimped, thereby sealing the capacitor element. Finally, a seat plate is disposed on the crimped portion to complete the electrolytic capacitor. Then, an aging treatment can be performed while applying a rated voltage.

[0141] The electrolytic capacitor may have at least one capacitor element, or may have a plurality of capacitor elements. The number of capacitor elements contained in the electrolytic capacitor may be determined according to the use.

[0142] [Embodiment]

[0143] Hereinafter, the present invention will be described in more detail based on embodiments, but the present invention is not limited to the embodiments.

[0144] 《Embodiment 1》

[0145] An electrolytic capacitor with a rated voltage of 35V was manufactured according to the following procedure.

[0146] (a) Preparation of electrode foils and spacers

[0147] An aluminum foil with a thickness of 100 μm was etched to roughen the surface of the aluminum foil. The surface of the roughened aluminum foil was subjected to a chemical conversion treatment to form a dielectric layer, thereby obtaining an anode foil.

[0148] An aluminum foil with a thickness of 50 μm was etched to roughen the surface of the aluminum foil, thereby obtaining a cathode foil.

[0149] A cellulose non-woven fabric with a thickness of 50 μm was prepared as a raw material for the spacer.

[0150] (b) Fabrication of capacitor element

[0151] The anode foil, cathode foil, and spacer were cut. The length L1 in the short side direction of the anode foil was set to 9 mm, and the length L2 in the short side direction of the cathode foil was set to 12 mm. The spacer was sized to at least cover the opposed portion of the anode foil and the cathode foil.

[0152] Lead terminals were connected to the anode foil and the cathode foil respectively. With the cathode foil exposed from one side of the anode foil along the winding direction, the anode foil and the cathode foil were laminated with the spacer interposed therebetween. The length L1a in the short side direction of the non-opposed portion of the cathode foil was 3 mm, and the length in the short side direction of the portion of the spacer exposed from the anode foil was 1.5 mm. Next, while winding the respective lead terminals, the anode foil and the cathode foil were wound with the spacer interposed therebetween. The end of the spacer located on the outermost periphery of the wound body was fixed with a stop tape to obtain a capacitor element. The two lead terminals were led out from the side opposite to the side where the exposed portion of the cathode foil was provided in the capacitor element.

[0153] (c) Connection of current collector member

[0154] An aluminum foil with a thickness of 100 μm was cut to prepare Figure 3A a current collector member having the shape shown. This current collector member was welded to the non-opposed portion of the cathode foil by laser welding.

[0155] (d) Formation of dielectric layer

[0156] A chemical conversion treatment is performed on the capacitor element connected to the current collector member to form a dielectric layer on the cut surface of the anode foil and the surface of the current collector member.

[0157] (e) Preparation and infiltration of a conductive polymer dispersion

[0158] 3,4-Ethylenedioxythiophene and polystyrenesulfonic acid (PSS, weight average molecular weight 100,000) are dissolved in ion-exchanged water to prepare a mixed solution. While stirring the mixed solution, iron(III) sulfate (oxidizing agent) is added to carry out a polymerization reaction. Then, the reaction solution is dialyzed to remove unreacted monomers and oxidizing agents, and a conductive polymer dispersion containing polyethylenedioxythiophene (PEDOT / PSS) doped with approximately 5% by mass of PSS (doping agent) is obtained. The concentration of the conductive polymer in the conductive polymer dispersion is 1.5% by mass. The viscosity of the conductive polymer dispersion measured at room temperature (20 °C) using a vibrating viscometer (manufactured by SEKONIC Corporation, VM-100A) is 30 mPa·s.

[0159] In a reduced-pressure atmosphere (40 kPa), the capacitor element connected to the current collector member is immersed in the conductive polymer dispersion for 5 minutes and then dried to cause the conductive polymer to adhere.

[0160] (f) Infiltration of the electrolyte

[0161] Ethylene glycol (EG) is prepared as a solvent. 5-Sulfosalicylic acid (dibasic acid component) as a secondary sulfonic acid and triethylamine as a base component are dissolved in EG at a total concentration of 25% by mass to prepare an electrolyte. The equivalent ratio of 5-sulfosalicylic acid to triethylamine is set to 2.0.

[0162] After the infiltration of the conductive polymer dispersion (e), in a reduced-pressure atmosphere (40 kPa), the capacitor element connected to the current collector member is immersed in the electrolyte for 5 minutes.

[0163] (g) Sealing of the capacitor element

[0164] The capacitor element infiltrated with the electrolyte is sealed to complete the electrolytic capacitor (A1) as shown. Then, while applying the rated voltage, aging is carried out at 95 °C for 90 minutes. Figure 2 shown.

[0165] <Evaluation>

[0166] For the electrolytic capacitor A1, the ESR is measured (measurement temperature 20 °C). The evaluation results are expressed in the form of relative values of the ESR with respect to the electrolytic capacitor B1 manufactured in Comparative Example 1.

[0167] <<Example 2>>

[0168] In the production (b) of the capacitor element, the length of the anode foil in the short side direction is set to 12 mm, the length of the cathode foil in the short side direction is set to 9 mm, the spacer is cut into a size that can at least cover the opposed portion of the anode foil and the cathode foil, and the anode foil and the cathode foil are laminated with the spacer therebetween such that the anode foil and the spacer are exposed from one side of the cathode foil along the winding direction. In the connection (c) of the current collector member, an aluminum foil with a thickness of 100 μm is cut, and a current collector member having the shape shown in Figure 3C is prepared and welded to the non-opposed portion of the anode foil by laser welding.

[0169] Except as described above, the operation is the same as in Example 1 to produce an electrolytic capacitor A2, and the evaluation is performed in the same manner. The results are shown in Table 1. The length of the non-opposed portion of the anode foil in the short side direction is 3 mm, and the length of the portion of the spacer exposed from the cathode foil in the short side direction is 1.5 mm.

[0170] <<Example 3>>

[0171] In the production (b) of the capacitor element, the length of the anode foil in the short side direction is set to 12 mm, the length of the cathode foil in the short side direction is also set to 12 mm, the spacer is cut into a size that can cover the opposed portion of the anode foil and the cathode foil, and the anode foil and the cathode foil are laminated with the spacer therebetween such that the cathode foil and the spacer are exposed from one side of the anode foil along the winding direction and the anode foil and the spacer are exposed from one side of the cathode foil along the winding direction. In the connection (c) of the current collector member, an aluminum foil with a thickness of 100 μm is cut, and a current collector member having the shape shown in Figure 3A and a current collector member having the shape shown in Figure 3C are prepared, and as shown in Figure 7 , they are respectively welded to the non-opposed portions of the cathode foil and the anode foil by laser welding.

[0172] Except as described above, the operation is the same as in Example 1 to produce an electrolytic capacitor A3, and the evaluation is performed in the same manner. The results are shown in Table 1. The length of the non-opposed portion of the anode foil in the short side direction is 3 mm, the length of the non-opposed portion of the cathode foil in the short side direction is 3 mm, and the lengths of the portions of the spacer exposed from the anode foil and the cathode foil in the short side direction are 1.5 mm respectively.

[0173] <<Comparative Example 1>>

[0174] In the production (b) of the capacitor element, the anode foil and the cathode foil are cut into the same size (the length of the short side is 9 mm for both), no non-opposed portion is formed, and no current collector member is used. Except as described above, the operation is the same as in Example 1 to produce an electrolytic capacitor B1, and the evaluation is performed in the same manner. The results are shown in Table 1.

[0175]

Table 1

[0176] Electrolytic capacitor ESR A1 0.78 A2 0.82 A3 0.30 B1 1

[0177] Industrial Applicability

[0178] The present invention can suppress an increase in ESR, and thus is particularly suitable for electrolytic capacitors that conduct high-ripple current.

[0179] Explanation of Reference Numerals

[0180] 100: Electrolytic capacitor

[0181] 10: Winding body

[0182] 10X: First end portion

[0183] 10Y: Second end portion

[0184] 11: Anode foil

[0185] 11a: First non-opposing portion

[0186] 12: Cathode foil

[0187] 12a: Second non-opposing portion

[0188] 13: Spacer

[0189] 14: Anti-unwinding tape

[0190] 15A: First lead terminal

[0191] 15B: Second lead terminal

[0192] 20, 20A to 20D: Current collecting members

[0193] 21: First current collecting member

[0194] 22: Second current collecting member

[0195] 20a: Notch

[0196] 30: Sealing member

[0197] 40: Base plate

[0198] 50A, 50B: External leads

[0199] 60: Bottomed housing.

Claims

1. An electrolytic capacitor comprising: A capacitor element including a wound body in which a first electrode foil and a second electrode foil facing each other are wound, a first lead terminal connected to the first electrode foil, and a second lead terminal connected to the second electrode foil; A first current collector member connected to the first electrode foil; A second current collector member connected to the second electrode foil; And A case housing the capacitor element, the first current collector member, and the second current collector member, The first electrode foil has a first opposed portion facing the second electrode foil and a first non-opposed portion not facing the second electrode foil, and the first non-opposed portion is located at a first end portion in the winding axis direction of the wound body, The first lead terminal and the second lead terminal are led out from the first end portion side, The first current collector member is disposed on the first end portion side of the wound body and connected to the first non-opposed portion of the first electrode foil. The second electrode foil has a second opposed portion facing the first electrode foil and a second non-opposed portion not facing the first electrode foil, and the second non-opposed portion is located at a second end portion opposite to the first end portion in the winding axis direction of the wound body, The second current collector member is disposed on the second end portion side of the wound body and connected to the second non-opposed portion of the second electrode foil, The first current collector member is connected to the first electrode foil on the outermost peripheral side of the wound body and has an opening through which the first lead terminal and the second lead terminal pass, and the first current collector member is separated from the first lead terminal.

2. The electrolytic capacitor according to claim 1, wherein, The first current collector member includes a metal foil containing a valve-acting metal.

3. The electrolytic capacitor according to claim 1, wherein The electrolytic capacitor further includes a conductive polymer, The conductive polymer is interposed between the first electrode foil and the second electrode foil and adheres to the first current collector member.

4. The electrolytic capacitor according to claim 3, wherein, The second current collector member includes a metal foil containing a valve-acting metal.

5. The electrolytic capacitor according to any one of claims 1 to 4, wherein, The first current collector member electrically connects a plurality of portions of the first non-opposed portion at different distances from the center of the wound body to each other.

6. The electrolytic capacitor according to any one of claims 1 to 4, wherein, The first electrode foil is an anode foil.

7. The electrolytic capacitor according to any one of claims 1 to 4, wherein, The first electrode foil is a cathode foil.

8. The electrolytic capacitor according to any one of claims 1 to 4, wherein, The electrolytic capacitor further includes an electrolyte.

9. The electrolytic capacitor according to any one of claims 1 to 4, wherein, The first current collector member is a plate-like member covering at least a part of the first end portion.

10. The electrolytic capacitor according to any one of claims 1 to 4, wherein, The first current collector member has at least one of a plurality of through holes and a plurality of slits.

11. The electrolytic capacitor according to any one of claims 1 to 4, wherein, The first current collector member has a dielectric layer formed on the surface.

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