Electrolytic capacitor, method for manufacturing same, and holder

Abstract

This electrolytic capacitor is provided with: a capacitor element formed by winding an anode foil and a cathode foil via a separator; a case for housing the capacitor element; a sealing body for sealing the opening of the case; and a holder that is disposed between the capacitor element and the sealing body and holds an antioxidant that is more easily oxidized than the sealing body.

Description

Technical Field

[0001] The present invention relates to an electrolytic capacitor, a manufacturing method thereof and a retainer. Background Art

[0002] The electrolytic capacitor has a structure in which the opening of a bottomed cylindrical outer casing containing a capacitor element formed by winding an anode foil and a cathode foil via a separator is fitted and sealed with a sealing body such as butyl rubber (for example, see Patent Documents 1 and 2). The capacitor element contains an electrolyte, and as the electrolyte dries or leaks, the characteristics of the electrolytic capacitor deteriorate.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2017 / 090241

[0006] Patent Document 2: International Publication No. 2020 / 059091 Summary of the invention

[0007] The problem to be solved by the invention

[0008] The sealing body gradually oxidizes due to the action of oxygen or electrolyte in the outer case. The oxidation of the sealing body becomes significant when the electrolytic capacitor is used for a long time in a high temperature environment such as near an engine or a computer.

[0009] When the sealing body is oxidatively degraded, cracks may occur in the sealing body, for example, at the contact portion with the case or at the insertion hole of the electrode terminal, thereby accelerating the drying of the electrolyte solution and possibly degrading the characteristics of the electrolytic capacitor.

[0010] For example, Patent Document 2 describes supplying a fat-soluble antioxidant from a separator to a sealing body. However, oxidation of the surface of the sealing body in an area not in contact with the separator may not be effectively suppressed. Therefore, the long-term reliability of the electrolytic capacitor may not be fully ensured.

[0011] Therefore, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an electrolytic capacitor, a method for manufacturing the same, and a holder capable of improving reliability.

[0012] Technical solutions to solve problems

[0013] The electrolytic capacitor of the present invention is characterized in that it has: a capacitor element, which is formed by winding an anode foil and a cathode foil via a separator; a case, which accommodates the capacitor element; a sealing body, which seals the opening of the case; and a retaining member, which is arranged between the capacitor element and the sealing body and retains an antioxidant that is more easily oxidized than the sealing body.

[0014] In the electrolytic capacitor, the holder may be a sheet-like member that covers at least a portion of a surface of the sealing body.

[0015] In the electrolytic capacitor, a pair of lead terminals extending from the anode foil and the cathode foil respectively may be provided at the lower portion of the capacitor element, the sealing body may have a pair of insertion holes for respectively inserting the pair of lead terminals, and the retaining member may have a pair of insertion holes for respectively inserting the pair of lead terminals.

[0016] In the electrolytic capacitor, the holder may include a slit extending from at least one of the pair of insertion holes to an end edge of the holder.

[0017] In the electrolytic capacitor, the diameter of the pair of insertion holes may be 0.5 to 2 times the diameter of the pair of lead terminals.

[0018] In the electrolytic capacitor, a pair of lead terminals extending from the anode foil and the cathode foil respectively may be provided at the lower portion of the capacitor element, the sealing body may have a pair of insertion holes for respectively inserting the pair of lead terminals, and the retaining member may have a pair of slits for respectively passing the pair of lead terminals.

[0019] In the electrolytic capacitor, at least one of the pair of slits may extend to an end edge of the holder.

[0020] In the electrolytic capacitor, a pair of lead terminals extending from the anode foil and the cathode foil respectively may be provided at the lower portion of the capacitor element, the sealing body may have a pair of insertion holes for respectively inserting the pair of lead terminals, and the retaining member may have a pair of cutouts respectively engaged with the pair of lead terminals.

[0021] In the electrolytic capacitor, the separator may extend from the anode foil and the cathode foil toward the holder and be pressed against the holder.

[0022] In the electrolytic capacitor, the antioxidant may include at least one of a photo-oxidant, a vitamin-based antioxidant, an amine-based antioxidant, a phenol-based antioxidant, a phosphorus-based antioxidant, and a carbohydrate-based antioxidant.

[0023] In the electrolytic capacitor, the holding member may have an organic fiber, an inorganic fiber, or a resin fiber as a base material, or may be a gel-like medium.

[0024] In the electrolytic capacitor, the retainer may be bonded to the sealing body by an adhesive swelled by an electrolyte impregnated in the separator.

[0025] In the electrolytic capacitor, the holder may hold a solution containing 2.5 wt % to 20 wt % of α-tocopherol as the antioxidant.

[0026] In the electrolytic capacitor, a conductive polymer layer may be formed on the capacitor element.

[0027] The manufacturing method of the electrolytic capacitor of the present invention is characterized in that it includes: a process of installing a sealing body on a capacitor element formed by winding an anode foil and a cathode foil via a separator via a retaining member that retains an antioxidant that is more easily oxidized than the sealing body; and a process of housing the capacitor element in a shell and sealing the opening of the shell with the sealing body.

[0028] In the manufacturing method, the capacitor element may have a pair of lead terminals extending from the anode foil and the cathode foil respectively, and in the process of sealing the opening of the shell using the sealing body, the pair of lead terminals are respectively inserted into a pair of insertion holes of the retaining member, and the pair of lead terminals inserted into the pair of insertion holes are respectively inserted into a pair of through holes of the sealing body.

[0029] In the manufacturing method, the capacitor element may have a pair of lead terminals extending from the anode foil and the cathode foil respectively, and in the step of sealing the shell opening using the sealing body, the pair of lead terminals are respectively passed through a pair of slits of the retaining member, and the pair of lead terminals passing through the pair of slits are respectively inserted into a pair of insertion holes of the sealing body.

[0030] In the manufacturing method, the capacitor element may have a pair of lead terminals extending from the anode foil and the cathode foil respectively, and in the step of sealing the shell opening using the sealing body, the pair of lead terminals are respectively embedded in a pair of cutouts of the retaining member, and the pair of lead terminals embedded in the pair of cutouts are respectively inserted into a pair of insertion holes of the sealing body.

[0031] The retainer of the present invention is characterized in that the retainer is arranged in an electrolytic capacitor, the electrolytic capacitor has a capacitor element formed by winding an anode foil and a cathode foil via a separator, a shell for accommodating the capacitor element, and a sealing body for sealing an opening of the shell, and the retainer is arranged between the capacitor element and the sealing body to retain an antioxidant that is more easily oxidized than the sealing body.

[0032] In the holder, the antioxidant may include at least one of a photo-oxidation antioxidant, a vitamin-based antioxidant, an amine-based antioxidant, a phenol-based antioxidant, a phosphorus-based antioxidant, and a carbohydrate-based antioxidant.

[0033] In the holder, the holder may hold a solution containing 2.5 wt % to 20 wt % of α-tocopherol as the antioxidant.

[0034] Effects of the Invention

[0035] According to the present invention, the reliability of an electrolytic capacitor can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a diagram showing an example of an aluminum electrolytic capacitor.

[0037] Figure 2 It is along Figure 1 A cross section of an AA line aluminum electrolytic capacitor 1.

[0038] Figure 3 It is a perspective view showing an example of a capacitor element.

[0039] Figure 4 yes Figure 3 An enlarged view of the portion indicated by reference numeral P.

[0040] Figure 5 (A) is a top view of a retaining member provided with a pair of insertion holes, (B) is a top view of a retaining member provided with a pair of cuts, (C) is a top view of a retaining member provided with a pair of cutouts, (D) is a top view of a retaining member provided with a cut extending to the end edge of the retaining member, and (E) is a top view of a retaining member provided with a pair of insertion holes and cuts extending from each insertion hole to the end edge of the retaining member.

[0041] Figure 6 This is a flowchart showing an example of a manufacturing process of an aluminum electrolytic capacitor.

[0042] Figure 7 This is a perspective view showing an example of a process of attaching a sealing body to a capacitor element via a holder.

[0043] Figure 8 This is a perspective view showing another example of the process of attaching the sealing body to the capacitor element via the holder.

[0044] Fig. 9 It is a graph showing the temporal change of the reduction rate of electrostatic capacitance of the example and the comparative example. DETAILED DESCRIPTION

[0045] [Implementation Method]

[0046] (Structure of aluminum electrolytic capacitor)

[0047] Figure 1 1 is a diagram showing an example of an aluminum electrolytic capacitor 1 . Figure 1 The upper surface and the rough surface of the aluminum electrolytic capacitor 1 are shown. Figure 2 It is along Figure 1 A cross section of an AA line aluminum electrolytic capacitor 1.

[0048] The aluminum electrolytic capacitor 1 includes a capacitor element 10, a housing 11, a sealing body 12, and a holding member 14. In addition, as the aluminum electrolytic capacitor 1, a conductive polymer hybrid aluminum electrolytic capacitor is particularly cited in this example, but it is not limited to this. The aluminum electrolytic capacitor 1 is mounted on an electronic circuit substrate, for example, for coupling, decoupling, and smoothing.

[0049] Figure 3 1 is a three-dimensional diagram showing an example of a capacitor element 10. The capacitor element 10 is formed by winding an anode foil 101, a cathode foil 102 and a separator (electrolytic paper) 103. A pair of lead terminals 112 and 113 extend from the lower part of the capacitor element 10. A pair of leads 110 and 111 extend from the round rod parts of the lead terminals 112 and 113, respectively. The lead terminals 112 and 113 are respectively joined to the anode foil and the cathode foil by joining means such as riveting, and function as the anode terminal and the cathode terminal of the aluminum electrolytic capacitor 1. In addition, in the present embodiment, a lead-type aluminum electrolytic capacitor 1 is listed, but it is not limited to this, and it can also be a surface-mounted type.

[0050] Anode foil 101 and cathode foil 102 are formed of valve metals such as aluminum, tantalum, titanium and niobium, or alloy foils or vapor-deposited foils thereof, or foils with activated carbon formed on the surface. The surface of anode foil 101 is etched to increase the electrode area. Furthermore, an anodic oxide film is formed on the surface of anode foil 101. Therefore, anode foil 101 is insulated from other components. The anodic oxide film functions as a dielectric, thereby playing the role of a capacitor.

[0051] On the other hand, an oxide film is formed as necessary on the surface of cathode foil 102. Alternatively, an inorganic layer or a carbon layer may be formed on the surface of cathode foil 102, and in this case, a conductive polymer described later is formed on the surface.

[0052] The separator 103 is wound in a state of being sandwiched between the anode foil 101 and the cathode foil 102. The separator 103 is made of at least one material selected from cellulose, rayon, and glass fiber. The separator 103 is impregnated with an electrolyte and a conductive polymer. In addition, when the aluminum electrolytic capacitor 1 is not a conductive polymer hybrid capacitor, no conductive polymer is used.

[0053] The electrolyte can contain a diether compound of a polyol, a sulfone compound, a lactone compound, a carbonate compound, a polyol, a monovalent alcohol, etc. They can be used alone or in combination. As the lactone compound, gamma-butyrolactone and gamma-valerolactone, etc. can be used. As the carbonate compound, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, ethylene carbonate, propylene carbonate, and fluoroethylene carbonate, etc. can be contained as a solvent. It is particularly preferred to use ethylene glycol, polyalkylene glycol, gamma-butyrolactone, and cyclopentane sulfone.

[0054] The electrolyte may also contain a solute. As a solute, an acid component, an alkali component, a salt composed of an acid component and an alkali component, a nitro compound, and a phenol compound, etc. may be used. In addition, an organic acid, an inorganic acid, and a composite compound of an organic acid and an inorganic acid may also be used. As an organic acid, carboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, maleic acid, succinic acid, glutaric acid, adipic acid, benzoic acid, 4-hydroxybenzoic acid, 1,6-decanedicarboxylic acid, 1,7-octanedicarboxylic acid, and azelaic acid may be used. As an inorganic acid, boric acid, phosphoric acid, phosphorous acid, hypophosphorous acid, phosphate esters, and phosphoric acid diesters may be used. As a composite compound of an organic acid and an inorganic acid, boron disalicylic acid, boron dioxalic acid, and boron diglycolic acid may be used.

[0055] As the base component, primary to tertiary amines, quaternary ammonium, and quaternary amidinium can be used. As primary to tertiary amines, for example, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, aniline, N,N-diisopropylethylamine, tetramethylethylenediamine, and hexamethylenediamine can be used. As quaternary ammonium, for example, tetramethylammonium, triethylmethylammonium, and tetraethylammonium can be used. As quaternary amidinium, for example, ethyldimethylimidazolium and tetramethylimidazolium can be used.

[0056] The housing 11 is formed of aluminum and has a bottomed cylindrical shape with an opening at the top blocked. The housing 11 covers the capacitor element 10 and the sealing body 12 and functions as an outer package of the aluminum electrolytic capacitor 1. In addition, the shape of the housing 11 is not limited to a cylindrical shape, but may also be a square cylindrical shape. In addition, a sleeve or a resin layer may be formed on the outside of the housing 11.

[0057] In addition, the electrolyte may contain an absorbent for absorbing hydrogen generated inside the case 11. As the absorbent, p-nitrobenzyl alcohol is preferred, and its addition amount is preferably 0.5 to 1.5 wt % in the electrolyte. This is because if it is less than 0.5 wt %, the hydrogen absorption effect is small, and on the other hand, if it exceeds 1.5 wt %, the withstand voltage characteristics of the aluminum electrolytic capacitor 1 may be reduced.

[0058] The sealing body 12 is a substantially cylindrical member formed of an elastic member such as butyl rubber or vulcanized rubber, or a phenolic resin member. The sealing body 12 is adjacent to the capacitor element 10 via a retaining member 14 holding an antioxidant, and seals the opening at the bottom of the housing 11. The retaining member 14 in this embodiment is, for example, a sheet-shaped member, but is not limited thereto. The lead terminals 112 and 113 are inserted into a pair of insertion holes 120 formed in the sealing body 12.

[0059] A constricted groove 11a that is recessed relative to other portions is formed on the outer peripheral surface near the opening of the housing 11. The constricted groove 11a corresponds to the thin diameter portion of the housing 11. The sealing body 12 seals the opening of the housing 11 while being sufficiently compressed by the constricted groove 11a to maintain high airtightness.

[0060] The sealing body 12 is preferably formed of a raw material such as butyl rubber having a small swelling rate relative to the solvent of the electrolyte contained in the separator 103 of the capacitor element 10. For example, when the electrolyte contains ethylene glycol, impurities extracted by the ethylene glycol may swell the sealing body 12, but by using the sealing body 12 of butyl rubber, the influence on the characteristics of the aluminum electrolytic capacitor 1 can be reduced. As for the characteristics of butyl rubber, as an example, even if immersed in a solvent of ethylene glycol at 125 (° C.) for more than 2000 hours, the swelling rate is expected to be 2 (wt%).

[0061] However, the sealing body 12 is gradually oxidized by the oxygen in the case 11 or the electrolyte in the separator. If the sealing body 12 is degraded by oxidation, cracks may be generated in the sealing body 12, for example, at the contact portion with the case 11 or the insertion hole 120, and thus the drying of the electrolyte may be accelerated, and the characteristics of the aluminum electrolytic capacitor 1 may be degraded, thereby reducing the reliability.

[0062] Therefore, a retainer 14 is arranged between the sealing body 12 and the capacitor element 10. The retainer 14 retains an antioxidant that is more easily oxidized than the sealing body 12. Therefore, the retainer 14 suppresses oxidation by supplying an antioxidant to the surface of the sealing body 12. Since the antioxidant supplied by the retainer 14 is more easily oxidized than the sealing body, oxidation of the sealing body 12 is suppressed during oxidation of the antioxidant. As a result, the reliability of the aluminum electrolytic capacitor 1 is improved. In addition, the retainer 14 may also be a gel-like monomer or the like.

[0063] As the antioxidant, preferably, there can be mentioned antioxidants with reducing action such as photo-oxidants, vitamin antioxidants, amine antioxidants, phenolic antioxidants, phosphorus antioxidants and carbohydrate antioxidants. In addition, the antioxidant can also be a combination of multiple types of the above antioxidants. Vitamins such as α-tocopherol, amine antioxidants such as uric acid, and phenolic antioxidants such as hydroquinone are preferred because they maintain the antioxidant function for a long time.

[0064] Examples of the photo-oxidation inhibitor include bis(2,2,6,6-tetramethyl-1-(octyloxy)-4-piperidinyl) ester, 1,1-dimethylethyl hydroperoxyoctane reaction product, bis(1,2,2,6,6-pentamethyl-4-piperidinyl)-[(3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl)methyl]butylmalonate, 2,4-bis[N-butyl-N-(1-cyclohexyloxy-2,2,6,6-tetramethylpyridinyl-4-yl)amino]-6-(2-hydroxyethylamine)-1,3,5-triazine, bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, and methyl(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate.

[0065] Examples of the vitamin-based antioxidants include tocopherol, tocotrienol, and ascorbic acid.

[0066] Examples of the amine antioxidant include uric acid, phenyl-1-naphthylamine, diphenyl-p-phenylenediamine, dipyridylamine, phenothiazine, N,N′-diisopropyl-p-phenylenediamine, N-phenyl-N′-isopropyl-p-phenylenediamine, and dialkyldiphenylamine (DDPA).

[0067] Examples of the phenolic antioxidant include 6-di-tert-butyl-p-cresol, 2,6-diphenyl-4-octadecyloxyphenol, stearyl (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, distearyl (3,5-di-tert-butyl-4-hydroxybenzyl) phosphonate, tridecyl-3,5-di-tert-butyl-4-hydroxybenzyl thioacetate, bis [3-(3-tert-butyl-4-hydroxy-5-methylphenyl) propionate] [ethylenebis (oxyethylene)] ester, thiodiethylenebis [(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 4,4'-thiobis (6-tert-butyl-m-cresol) and 2-octylthio-4,6-bis (3,5-di-tert-butyl-4-hydroxyphenoxy) -s-triazine.

[0068] Examples of the phosphorus antioxidant include triphenyl phosphite, tris(2,4-di-tert-butylphenyl) phosphite, tris(2,5-di-tert-butylphenyl) phosphite, tris(nonylphenyl) phosphite, tris(dinonylphenyl) phosphite, tris(mono- and di-mixed nonylphenyl) phosphite, diphenyl acid phosphite, 2,2′-methylenebis(4,6-di-tert-butylphenyl) octyl phosphite, diphenyldecyl phosphite, diphenyloctyl phosphite, bis(nonylphenyl)pentaerythritol phosphite, phenyl diisodecyl phosphite, tributyl phosphite, tris(2-ethylhexyl) phosphite, tricaprate phosphite, and trilauryl phosphite.

[0069] Examples of the sugar antioxidant include glucose, arabinose, fructose, maltose, lactose, and sorbitol.

[0070] In addition, the retainer 14 is preferably made of a base material such as cellulose, polysaccharides such as rayon and agar, and organic media such as gelatin, or resin fibers such as polypropylene and polystyrene, and inorganic fibers such as glass fibers containing silicate glass, either alone or in combination, to retain the antioxidant. In addition, the retainer 14 may be a gel-like monomer, or a gel-like substance may be formed on the retainer 14.

[0071] Since the retainer 14 is a sheet-like component that covers at least a portion of the surface of the sealing body 12, the antioxidant can be easily diffused to the surface of the sealing body 12 without changing the height of the aluminum electrolytic capacitor 1. The retainer 14 can also be at least partially bonded to the surface of the sealing body 12 by an adhesive, for example. At this time, if a polyether that swells with an electrolyte is used as an adhesive, the permeability of the antioxidant is good, so the antioxidant can diffuse in the adhesive. In addition, the thickness of the retainer 14 is, for example, 5 to 3000 (μm). More specifically, the retainer 14 only needs to have a thickness of 30 to 500 (μm) that can fully supply the antioxidant.

[0072] In addition, the holder 14 has a pair of insertion holes 140 into which the pair of lead terminals 112 and 113 are respectively inserted. In the manufacturing process of the aluminum electrolytic capacitor 1, the holder 14 is mounted on the capacitor element 10 in a state directly stacked on the sealing body 12. At this time, since the lead terminals 112 and 113 are respectively inserted into the insertion holes 140, at least a portion of the edge of the insertion hole 140 is introduced into the insertion hole 120 of the sealing body 12. Therefore, the antioxidant is supplied from the holder 14 into the insertion hole 120, and oxidation in the insertion hole 120 is effectively suppressed.

[0073] Figure 4 yes Figure 31 is an enlarged view of the portion indicated by reference numeral P. In capacitor element 10 , anode foil 101 and cathode foil 102 are stacked with separator 103 interposed therebetween. Separator 103 extends from anode foil 101 and cathode foil 102 toward holder 14 and contacts holder 14 .

[0074] More specifically, the separator 103 is exposed from the ends of the anode foil 101 and the cathode foil 102. In the manufacturing process of the aluminum electrolytic capacitor 1, the sealing body 12 and the retaining member 14 are installed on the capacitor element 10. When they are housed in the housing 11, the separator 13 is pressed against the surface of the retaining member 14 and becomes bent.

[0075] Therefore, the separator 103 exerts elastic force in the height direction of the aluminum electrolytic capacitor 1, so that the retainer 14 contacts the surface of the sealing body 12. Therefore, the contact area between the retainer 14 and the surface of the sealing body 12 can be fully ensured, and the antioxidant can be appropriately diffused to the surface of the sealing body 12. In addition, the separator 103 does not need to be pressed against the retainer 14 on the entire lower surface of the capacitor element 10, as long as it is pressed against the retainer 14 on at least a part of the lower surface of the capacitor element 10 (for example, more than 50% of the surface area of ​​the sealing body 12). In addition, the length of the protruding portion of the separator 103 from the anode foil 101 and the cathode foil 102 is preferably set to be longer than the distance M between the anode foil 101 and the cathode foil 102 and the retainer, for example, 0.1 to 4.0 (mm). More specifically, it is preferably set to 0.25 to 4.0 (mm) so that the retainer 14 is not easily damaged.

[0076] In addition, the separator 103 may contain an antioxidant. In this case, the antioxidant is supplied from the separator 103 to the holder 14 .

[0077] Figure 5 (A) to (D) show a plurality of examples of the holder 14 . Figure 5 (A) is a top view of a retainer 14 provided with a pair of insertion holes 140. Each insertion hole 140 has a circular shape. At least a portion of the edge of the insertion hole 140 is introduced into the insertion hole 120 of the sealing body 12 to supply an antioxidant to the wall surface of the sealing body 12. Therefore, the diameter of each insertion hole 140 is preferably smaller than the diameter of the lead terminals 112 and 113. For example, the diameter of the insertion hole 140 is preferably set to 0.5 to 2 times the diameter of the lead terminals 112 and 113. In addition, the diameter of the retainer 14 is preferably the same as that of the sealing body 12, or is larger than the diameter of the sealing body 12 in consideration of the deflection of the retainer 14. In addition, even if the diameter of the retainer 14 is smaller than the diameter of the sealing body 12, the long-term reliability of the aluminum electrolytic capacitor 1 can be improved.

[0078] Since the lead terminals 112 and 113 are respectively inserted into the insertion holes 140, as described above, at least a portion of the edge of the insertion hole 140 is introduced into the insertion hole 120 of the sealing body 12. Therefore, an antioxidant is supplied from the holder 14 into the insertion hole 120, effectively suppressing oxidation in the insertion hole 120. In addition, the shape of the insertion hole 140 is not limited to a circle, and may be, for example, a triangle or a rectangle.

[0079] Figure 5 (B) is a top view of the holder 14 provided with a pair of slits 141. Each slit 141 has a cross shape as an example, but is not limited thereto. The slits 141 are slits extending over the entire thickness of the holder 14. Compared with the case where the insertion hole 140 is provided, the holder 14 of this example is not hollowed out, so it can retain more antioxidants.

[0080] Since the lead terminals 112 and 113 are respectively passed through the slits 141, at least a portion of the edge of the slits 141 is introduced into the insertion hole 120 of the sealing body 12, similarly to the case of the insertion hole 140. Therefore, the antioxidant is supplied from the holder 14 into the insertion hole 120, and oxidation in the insertion hole 120 is effectively suppressed.

[0081] Figure 5 (C) is a top view of the holder 14 provided with a pair of cutouts 142. As an example, the cutouts 142 have a shape obtained by cutting the end of the holder 14 into a substantially U-shape. The lead terminals 112 and 113 are respectively fitted into the cutouts 142. The cutouts 142 can set the space through which the lead terminals 112 and 113 pass to be larger than the insertion holes 140 and the cutouts 141. Therefore, in the manufacture of the aluminum electrolytic capacitor 1, the mounting of the holder 14 relative to the capacitor element 10 becomes easy.

[0082] Figure 5 (D) is a top view of the holder 14 provided with slits 143 extending to the end edge of the holder 14. Each slit 143 has a cross shape as an example, but is not limited to this. The slit 143 partially reaches the end edge of the holder 14. Therefore, in the manufacture of the aluminum electrolytic capacitor 1, it is easier to pass the lead terminals 112 and 113 through the slit 143 than the above-mentioned slit 141, and the mounting of the holder 14 relative to the capacitor element 10 becomes easier. In addition, the holder 14 can also be formed in a manner that only one of the pair of slits 141 reaches the end edge of the holder 14.

[0083] Figure 5(E) is a top view of the holder 14 provided with a pair of insertion holes 140 and slits 144 extending from each insertion hole 140 to the end edge of the holder 14. The slits 144 extend linearly from each insertion hole 140 to the end edge of the holder 14. Therefore, in the manufacture of the aluminum electrolytic capacitor 1, compared with the case where the slits 144 are not provided and only the insertion holes 140 are provided, the lead terminals 112 and 113 are easily passed through the insertion holes 140, and the mounting of the holder 14 relative to the capacitor element becomes easy. In addition, the slits 144 may be formed only in one of the pair of insertion holes 140.

[0084] (Manufacturing process of aluminum electrolytic capacitors)

[0085] Figure 6 1 is a flowchart showing an example of a manufacturing process of the aluminum electrolytic capacitor 1. The manufacturing process of the aluminum electrolytic capacitor 1 is an example of a method for manufacturing an electrolytic capacitor.

[0086] First, lead terminals 112 and 113 are connected to anode foil 101 and cathode foil 102 prepared in advance, respectively (step St1). As a connection method, riveting can be cited, but it is not limited to this.

[0087] Next, separator 103 , anode foil 101 , cathode foil 102 , and separator 103 are stacked in this order and wound, and the outer surfaces are fixed with a winding fixing tape, thereby manufacturing capacitor element 10 (step St2 ).

[0088] Next, a chemical reconversion process (step St3) is performed on capacitor element 10. As a result, the defects of the oxide film formed on the surface of anode foil 101 are repaired. In the chemical reconversion process, for example, a chemical conversion solution is used in which a solute such as an organic acid salt having a carboxylic acid group or an inorganic acid salt such as phosphoric acid is dissolved in an organic solvent or water.

[0089] Next, the capacitor element 10 is immersed in a conductive polymer dispersion containing water and an organic solvent in a reduced pressure atmosphere, and then the capacitor element 10 is pulled out of the conductive polymer dispersion (step St4). In this way, the conductive polymer can be impregnated into the winding body. In addition, in the manufacture of a normal aluminum electrolytic capacitor 1 that is not a conductive polymer hybrid aluminum electrolytic capacitor, this step is not performed.

[0090] Next, in a reduced pressure atmosphere, a predetermined amount of electrolyte is impregnated into the capacitor element 10 (step St5). In addition, the electrolyte may also be mixed with a solute in the conductive polymer dispersion. That is, the conductive polymer dispersion can be used as the electrolyte. In this case, the impregnation of the electrolyte and the impregnation of the conductive polymer are performed simultaneously. Thus, the capacitor element 10 is completed. In addition, a solution of the same antioxidant as the retainer 14 may be added to the electrolyte.

[0091] Next, the sealing body 12 is mounted on the capacitor element 10 via the retaining member 14 (step St6). The retaining member 14 is generated by, for example, pre-immersing a substrate such as an inorganic fiber such as cellulose, polysaccharide, and gelatin, or a resin fiber such as polypropylene and polystyrene in an antioxidant solution. At this time, the solvent of the antioxidant solution can also be removed by pre-drying the retaining member 14. In addition, the retaining member 14 can also be generated by immersing the above-mentioned substrate in a dispersion obtained by dispersing, for example, a powder or granular body of an antioxidant in a liquid. Furthermore, the retaining member 14 can also be impregnated with the same electrolyte as the separator 103.

[0092] Figure 7 1 is a perspective view showing an example of a process of attaching the sealing body 12 to the capacitor element 10 via the retainer 14. Figure 5 (A) shows a holder 14. Sealing member 12 is disposed on the lower surface of capacitor element 10 via holder 14. In this case, holder 14 may be bonded to the surface of sealing member 12 by an adhesive such as polyethylene glycol.

[0093] Leads 110, 111 and lead terminals 112, 113 extend downward from the lower surface of capacitor element 10. Therefore, when arranged, leads 110, 111 and lead terminals 112, 113 are respectively inserted into a pair of insertion holes 140 of holder 14, and then inserted into a pair of insertion holes 120 of sealing body 12. Therefore, as described above, at least a portion of the edge of insertion hole 140 is introduced into insertion hole 120 of sealing body 12, so that antioxidant is supplied from holder 14 into insertion hole 120, and oxidation of the wall surface of insertion hole 120 is effectively suppressed.

[0094] Figure 8 1 is a perspective view showing another example of the process of attaching the sealing body 12 to the capacitor element 10 via the retainer 14. In this example, Figure 5(B) The retainer 14 shown. The sealing body 12 is arranged on the lower surface of the capacitor element 10 via the retainer 14. At this time, the leads 110, 111 and the lead terminals 112, 113 are introduced into the insertion hole 120 of the sealing body 12 with the edge of the slit 141 having a lower resistance than the edge of the insertion hole 140. In addition, the retainer 14 can also be bonded to the surface of the sealing body 12 by an adhesive such as polyethylene glycol.

[0095] When stacking, the lead terminals 112 and 113 are respectively passed through the slits 141 and then inserted into the pair of insertion holes 120 of the sealing body 12. Therefore, as described above, at least a portion of the edge of the slit 141 is introduced into the insertion hole 120 of the sealing body 12. Therefore, the antioxidant is supplied from the retainer 14 into the insertion hole 120, effectively suppressing the oxidation of the wall surface of the insertion hole 120. In addition, Figure 5 (D) and Figure 5 The mounting of each retainer 14 shown in (E) is also performed in the same manner as described above.

[0096] In addition, when using Figure 5 In the case of the holder 14 of (C), when stacking, the lead terminals 112 and 113 are respectively fitted into the cutouts 142 and inserted into the pair of insertion holes 120 of the sealing body 12. Therefore, as described above, in the manufacture of the aluminum electrolytic capacitor 1, the mounting of the holder 14 to the capacitor element becomes easy.

[0097] Refer again Figure 6 After sealing body 12 is attached, capacitor element 10 is housed in case 11 and sealed with sealing body 12 (step St7 ). Aluminum electrolytic capacitor 1 is manufactured in this manner.

[0098] Example

[0099] Next, examples of the aluminum electrolytic capacitor 1 are described. Aluminum electrolytic capacitors 1 of Examples No. 1 to 24 of the above-mentioned embodiment were produced. Aluminum electrolytic capacitors 1 of Examples No. 1 to 12 are ordinary electrolytic capacitors in which the electrolyte does not contain a conductive polymer, and aluminum electrolytic capacitors 1 of Examples No. 13 to 24 are conductive polymer hybrid aluminum electrolytic capacitors in which the electrolyte contains a conductive polymer. In addition, for comparison, aluminum electrolytic capacitors of Comparative Examples No. 1 to 3 without the retainer 14 were produced.

[0100] In each of the examples and comparative examples, the rated voltage of the aluminum electrolytic capacitor 1 is 25 (V), and the rated electrostatic capacitance of the aluminum electrolytic capacitor 1 is 470 (μF). In addition, the diameter of the case 11 is 10 (mm), and the height of the case 11 is 10 (mm).

[0101] (Example No. 1)

[0102] The lead-out terminal 112 of the anode is connected to the prepared anode foil 101. The lead-out terminal 113 of the cathode is connected to the cathode foil 102 which has a conductor layer on the end surface and has been pre-treated to improve the coating property. Then, the separator 103, the cathode foil 102, the separator 103, and the anode foil 101 are stacked in sequence, and the lead-out terminals 112 and 113 are wound while being wound, and the outer surface is fixed with a winding fixing tape, thereby making the capacitor element 10. At this time, the length of the part of the separator exposed from the anode foil 101 and the cathode foil 102 is 0.25 (mm) above and below. In addition, cellulose paper with a thickness of 60 (μm) is prepared as a retainer 14.

[0103] A γ-butyrolactone solution containing 35 (wt%) of 1,2,3,4-tetramethylimidazolium phthalate is prepared as an electrolyte. The capacitor element 10 is immersed in the electrolyte in a reduced pressure atmosphere. The base material of the retainer 14 is impregnated with a γ-butyrolactone solution containing a 10 (wt%) concentration of (±)-α-tocopherol, an antioxidant. Here, the retainer 14 is used. Figure 5 (A) The holder 14 and the sealing member 12 through which the lead terminals 112 and 113 and the leads 110 and 111 are passed are mounted on the capacitor element 10, and the case 11 is sealed with the sealing member 12 so that the capacitor element 10 is housed in the case 11. In this way, the aluminum electrolytic capacitor 1 is obtained.

[0104] (Example No. 2)

[0105] The following points are different from the manufacturing method of Example No. 1. The base material of the holder 14 is impregnated with the above-mentioned electrolyte solution containing (±)-α-tocopherol at a concentration of 10 (wt%).

[0106] (Example No. 3)

[0107] The following aspects are different from the manufacturing method of Example No. 1. The capacitor element 10 is immersed in an electrolyte containing 10 (wt%) (±)-α-tocopherol. After the retainer 14 not impregnated with an antioxidant is mounted on the capacitor element 10, the electrolyte is impregnated into the retainer 14 from the separator 103 of the capacitor element 10.

[0108] (Example No. 4)

[0109] The following points are different from the manufacturing method of Example No. 1: After the base material of the holder 14 is immersed in a γ-butyrolactone solution containing 10 (±)-α-tocopherol (wt%), the γ-butyrolactone as a solvent is removed from the holder 14 by drying.

[0110] (Example No. 5)

[0111] The following points are different from the manufacturing method of Example No. 1: The base material of the holder 14 is impregnated with a γ-butyrolactone solution containing (±)-α-tocopherol at a concentration of 2.5 (wt%).

[0112] (Example No. 6)

[0113] The following points are different from the manufacturing method of Example No. 1: The base material of the holder 14 is impregnated with a γ-butyrolactone solution containing (±)-α-tocopherol at a concentration of 20 (wt%).

[0114] (Example No. 7)

[0115] The following points are different from the manufacturing method of Example No. 1: The base material of the holder 14 is impregnated with a γ-butyrolactone solution containing uric acid at a concentration of 10 (wt %).

[0116] (Example No. 8)

[0117] The following points are different from the manufacturing method of Example No. 1: The base material of the holder 14 is impregnated with a γ-butyrolactone solution containing hydroquinone at a concentration of 10 (wt%).

[0118] (Example No. 9)

[0119] The following aspects are different from the manufacturing method of Example No. 1. The retainer 14 is used Figure 5 (D) The shape shown.

[0120] (Example No. 10)

[0121] The following points are different from the manufacturing method of Example No. 1. The retainer 14 is bonded to the surface of the sealing body 12 by polyethylene glycol as an adhesive.

[0122] (Example No. 11)

[0123] The following points are different from the manufacturing method of Example No. 1: The retainer 14 is formed by forming a gel containing (±)-α-tocopherol on the surface of the sealing body 12 .

[0124] (Example No. 12)

[0125] The following points are different from the manufacturing method of Example No. 1: The separator 103 is impregnated with the same antioxidant as that of the holder 14 .

[0126] (Example No. 13)

[0127] The following aspects are different from the manufacturing method of Example No. 1. For the capacitor element 10, before being immersed in the electrolyte, a rechemical conversion treatment is performed in an ammonium phosphate aqueous solution with a voltage of 50 (V) applied. After the capacitor element 10 is cleaned and dried, the capacitor element 10 is immersed in a PEDOT / PSS (poly (3,4-ethylenedioxythiophene) polystyrene sulfonate) dispersion of a conductive polymer in an atmosphere reduced from atmospheric pressure to -0.97 (MPa). A γ-butyrolactone solution containing 35 (wt%) of 1,2,3,4-tetramethylimidazolium phthalate is prepared as an electrolyte. The capacitor element 10 is immersed in the electrolyte in a reduced pressure atmosphere. A conductive polymer hybrid aluminum electrolytic capacitor is thus obtained.

[0128] (Example No. 14)

[0129] The following points are different from the manufacturing method of Example No. 13. The base material of the holder 14 is impregnated with the above-mentioned electrolyte solution containing (±)-α-tocopherol at a concentration of 10 (wt%).

[0130] (Example No. 15)

[0131] The following aspects are different from the manufacturing method of Example No. 13. The capacitor element 10 is immersed in an electrolyte containing 10 (wt%) (±)-α-tocopherol. After the retainer 14 not impregnated with an antioxidant is mounted on the capacitor element 10, the electrolyte is impregnated into the retainer 14 from the separator 103 of the capacitor element 10.

[0132] (Example No. 16)

[0133] The following points are different from the manufacturing method of Example No. 13: After the base material of the holder 14 is immersed in a γ-butyrolactone solution containing 10 (±)-α-tocopherol (wt%), the γ-butyrolactone as a solvent is removed from the holder 14 by drying.

[0134] (Example No. 17)

[0135] The following points are different from the manufacturing method of Example No. 13. The base material of the holder 14 is impregnated with a γ-butyrolactone solution containing (±)-α-tocopherol at a concentration of 2.5 (wt%).

[0136] (Example No. 18)

[0137] The following points are different from the manufacturing method of Example No. 13. The base material of the holder 14 is impregnated with a γ-butyrolactone solution containing (±)-α-tocopherol at a concentration of 20 (wt%).

[0138] (Example No. 19)

[0139] The following points are different from the manufacturing method of Example No. 13. The base material of the holder 14 is impregnated with a γ-butyrolactone solution containing uric acid at a concentration of 10 (wt %).

[0140] (Example No. 20)

[0141] The following points are different from the manufacturing method of Example No. 13. The base material of the holder 14 is impregnated with a γ-butyrolactone solution containing hydroquinone at a concentration of 10 (wt%).

[0142] (Example No. 21)

[0143] The following aspects are different from the manufacturing method of Example No. 13. The retainer 14 is used Figure 5 (D) The shape shown.

[0144] (Example No. 22)

[0145] The following points are different from the manufacturing method of Example No. 13. The retainer 14 is bonded to the surface of the sealing body 12 by polyethylene glycol as an adhesive.

[0146] (Example No. 23)

[0147] The following points are different from the manufacturing method of Example No. 13: The retainer 14 is formed by forming a gel containing (±)-α-tocopherol on the surface of the sealing body 12 .

[0148] (Example No. 24)

[0149] The following points are different from the manufacturing method of Example No. 13: The separator 103 is impregnated with the same antioxidant as that of the holder 14 .

[0150] (Comparative Example No. 1)

[0151] The following points are different from the manufacturing method of Example No. 1: The holder 14 is not attached to the capacitor element 10 .

[0152] (Comparative Example No. 2)

[0153] The following points are different from the manufacturing method of Example No. 13: The holder 14 is not attached to the capacitor element 10 .

[0154] (Comparative Example No. 3)

[0155] The following points are different from the manufacturing method of Example No. 1: No holder 14 is attached to capacitor element 10. Separator 103 is impregnated with an antioxidant.

[0156] (evaluate)

[0157] A rated voltage (25 (V) was applied to the aluminum electrolytic capacitors 1 of Examples No. 1 to 24 and the aluminum electrolytic capacitors of Comparative Examples No. 1 to 3, respectively, under an environment of 130 (° C.). The electrostatic capacitance C (μF) was measured 5000 hours and 8000 hours after the start of the application. The initial value of the electrostatic capacitance of each aluminum electrolytic capacitor 1 before the evaluation test was set to Co (μF), and the amount of change in the electrostatic capacitance 5000 hours and 8000 hours after the start of the application was set to ΔC (<0) (μF), and the reduction rate (%) of the electrostatic capacitance was calculated as ΔC / Co as an evaluation parameter.

[0158] [Table 1]

[0159]

[0160]

[0161] Table 1 shows the reduction rate (%) of the electrostatic capacitance after 5000 hours and 8000 hours as the evaluation results of each aluminum electrolytic capacitor 1 of Examples No. 1 to No. 12. In Examples No. 1 to No. 12, for the aluminum electrolytic capacitor 1 using (±)-α-tocopherol as an antioxidant, the concentration of the solution is shown.

[0162] [Table 2]

[0163]

[0164] Table 2 shows the reduction rate (%) of the electrostatic capacitance after 5000 hours and 8000 hours as the evaluation results of each aluminum electrolytic capacitor 1 of Examples No. 13 to No. 24. In Examples No. 13 to No. 24, the concentration of the solution of the aluminum electrolytic capacitor 1 using (±)-α-tocopherol as an antioxidant is shown.

[0165] [Table 3]

[0166]

[0167] Table 2 shows the reduction rate (%) of the electrostatic capacitance after 5000 hours and after 8000 hours as the evaluation results of each of the aluminum electrolytic capacitors 1 of Comparative Examples No. 1 to No. 3.

[0168] As can be seen from Tables 1 to 3, the reduction rate of electrostatic capacitance of each aluminum electrolytic capacitor 1 of Examples No. 1 to No. 24 is lower than that of the aluminum electrolytic capacitors of Comparative Examples No. 1 to No. 3. This is because, since the retainer 14 is provided between the capacitor element 10 and the sealing body 12, the antioxidant retained in the retainer 14 is supplied to the surface of the sealing body 12, the antioxidant is oxidized, and oxidation of the sealing body 12 is suppressed.

[0169] In addition, when the reduction rate of the electrostatic capacitance of each aluminum electrolytic capacitor 1 of Examples No. 1 to No. 12 is compared with the reduction rate of the electrostatic capacitance of each aluminum electrolytic capacitor 1 of Examples No. 13 to No. 24, the reduction rate of Examples No. 1 to No. 12 is greater. This is because the conductive polymer has the function of retaining the electrolyte. Therefore, in the case of a conductive polymer hybrid aluminum electrolytic capacitor in which the separator 103 is impregnated with the conductive polymer, the oxidation of the sealing body 12 is more effectively suppressed.

[0170] In addition, it can be seen from Tables 1 and 2 that, for the aluminum electrolytic capacitor 1 using (±)-α-tocopherol as an antioxidant, the concentration of the solution is preferably 2.5 to 20 (wt %).

[0171] In addition, even when the substrate of the retainer 14 is immersed in an electrolyte containing an antioxidant as in Examples No. 2 and No. 12, the reduction rate of electrostatic capacitance can be suppressed more than that of Comparative Examples No. 1 to No. 3. In addition, even when the antioxidant is impregnated from the separator 103 to the retainer 14 as in Examples No. 3 and No. 15, the reduction rate of electrostatic capacitance can be suppressed more than that of Comparative Examples No. 1 to No. 3. In addition, even when the solvent of the antioxidant impregnated from the separator 103 to the retainer 14 is removed as in Examples No. 4 and No. 16, the reduction rate of electrostatic capacitance can be suppressed more than that of Comparative Examples No. 1 to No. 3.

[0172] In addition, even when an antioxidant other than (±)-α-tocopherol is used as in Examples No. 7, 8, 19, and 20, the reduction rate of electrostatic capacitance can be suppressed more than that of Comparative Examples No. 1 to No. 3. In addition, even when the shape of the retainer 14 is changed as in Examples No. 9 and No. 21, the reduction rate of electrostatic capacitance can be suppressed more than that of Comparative Examples No. 1 to No. 3. In addition, even when the retainer 14 is bonded to the surface of the sealing body 12 using an adhesive as in Examples No. 10 and No. 22, the reduction rate of electrostatic capacitance can be suppressed more than that of Comparative Examples No. 1 to No. 3.

[0173] In addition, even when the retainer 14 is made of gel as in Examples No. 11 and No. 23, the reduction rate of electrostatic capacitance can be suppressed more than that of Comparative Examples No. 1 to No. 3. In addition, even when the separator 103 is impregnated with the same antioxidant as the retainer 14 as in Examples No. 12 and No. 24, the reduction rate of electrostatic capacitance can be suppressed more than that of Comparative Examples No. 1 to No. 3.

[0174] Fig. 9 This is a graph showing the temporal change in the reduction rate of electrostatic capacitance of Example No. 1 and Comparative Examples No. 1 and No. 3. Fig. 9 The horizontal axis and vertical axis of the graph represent time (h) and reduction rate (ΔC / Co) (%), respectively.

[0175] The difference in reduction rate between Example No. 1 and Comparative Example No. 1 is greater than the difference in reduction rate between Example No. 1 and Comparative Example No. 3. The aluminum electrolytic capacitor of Comparative Example No. 3 has a separator impregnated with an antioxidant, so the reduction rate is lower than that of Comparative Example No. 1 by suppressing oxidation of the sealing body.

[0176] However, in the case of Comparative Example No. 3, since the antioxidant is contained in the separator together with the electrolyte, it is difficult to achieve a sufficient supply amount. In addition, since the separator is in direct contact with the sealing body, the electrolyte easily flows to the sealing body, and compared with Example No. 1, the oxidation of the sealing body cannot be effectively suppressed.

[0177] Thus, according to the aluminum electrolytic capacitor 1, the manufacturing method thereof, and the holder 14 of the present embodiment, direct contact between the electrolyte contained in the separator 103 in the capacitor element 10 and the sealing body 12 is suppressed, and oxidation of the sealing body 12 is suppressed by supplying an antioxidant to the surface of the sealing body 12. Therefore, deterioration of the characteristics of the aluminum electrolytic capacitor 1 can be suppressed.

[0178] As mentioned above, although the embodiment of the present invention was described in detail, the present invention is not limited to this specific embodiment, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims.

Claims

1. An electrolytic capacitor, characterized in that: include: A capacitor element, which is formed by winding an anode foil and a cathode foil via a separator; a housing for housing the capacitor element; A sealing body, which seals the opening of the shell; and A holder is disposed between the capacitor element and the sealing body and holds an antioxidant that is more easily oxidized than the sealing body.

2. The electrolytic capacitor according to claim 1, characterized in that: The retainer is a sheet-like member that covers at least a portion of the surface of the sealing body.

3. The electrolytic capacitor according to claim 1 or 2, characterized in that: A pair of lead terminals extending from the anode foil and the cathode foil are provided at the bottom of the capacitor element. The sealing body has a pair of insertion holes through which the pair of lead terminals are respectively inserted. The holding member has a pair of insertion holes into which the pair of lead terminals are respectively inserted.

4. The electrolytic capacitor according to claim 3, characterized in that: The retainer has a slit extending from at least one of the pair of insertion holes to an end edge of the retainer.

5. The electrolytic capacitor according to claim 3, characterized in that: The diameter of the pair of insertion holes is 0.5 to 2 times the diameter of the pair of lead terminals.

6. The electrolytic capacitor according to claim 1 or 2, characterized in that: A pair of lead terminals extending from the anode foil and the cathode foil are provided at the bottom of the capacitor element. The sealing body has a pair of insertion holes through which the pair of lead terminals are respectively inserted. The holding member has a pair of slits through which the pair of lead terminals pass, respectively.

7. The electrolytic capacitor according to claim 6, characterized in that: At least one of the pair of slits extends to an end edge of the retainer.

8. The electrolytic capacitor according to claim 1 or 2, characterized in that: A pair of lead terminals extending from the anode foil and the cathode foil are provided at the bottom of the capacitor element. The sealing body has a pair of insertion holes through which the pair of lead terminals are respectively inserted. The retainer has a pair of cutouts that are respectively fitted with the pair of lead terminals.

9. The electrolytic capacitor according to claim 1 or 2, characterized in that: The separator extends from the anode foil and the cathode foil toward the holder and is pressed against the holder.

10. The electrolytic capacitor according to claim 1 or 2, characterized in that: The antioxidant contains at least one of a photo-oxidant, a vitamin antioxidant, an amine antioxidant, a phenol antioxidant, a phosphorus antioxidant and a carbohydrate antioxidant.

11. The electrolytic capacitor according to claim 1 or 2, characterized in that: The retainer is made of organic fibers, inorganic fibers or resin fibers as a base material, or is a gel-like medium.

12. The electrolytic capacitor according to claim 1 or 2, characterized in that: The retainer is bonded to the sealing body by an adhesive swollen by the electrolyte impregnated in the separator.

13. The electrolytic capacitor according to claim 1 or 2, characterized in that: The holder holds a solution containing 2.5 wt % to 20 wt % of α-tocopherol as the antioxidant.

14. The electrolytic capacitor according to claim 1 or 2, characterized in that: A conductive polymer layer is formed on the capacitor element.

15. A method for manufacturing an electrolytic capacitor, characterized in that: include: A step of attaching the sealing body to a capacitor element formed by winding an anode foil and a cathode foil with a separator therebetween, via a holder that holds an antioxidant that is more easily oxidized than the sealing body; and The step of housing the capacitor element in a case and sealing an opening of the case with the sealing body.

16. The method for manufacturing an electrolytic capacitor according to claim 15, wherein: The capacitor element has a pair of lead terminals extending from the anode foil and the cathode foil, respectively. In the step of sealing the opening of the housing with the sealing body, inserting the pair of lead terminals into the pair of insertion holes of the holder, respectively; The pair of lead terminals inserted into the pair of insertion holes are respectively inserted into the pair of insertion holes of the sealing body.

17. The method for manufacturing an electrolytic capacitor according to claim 15, wherein: The capacitor element has a pair of lead terminals extending from the anode foil and the cathode foil, respectively. In the step of sealing the opening of the housing with the sealing body, The pair of lead terminals are respectively passed through a pair of slits of the retaining member, The pair of lead terminals that have passed through the pair of slits are respectively inserted into the pair of insertion holes of the sealing body.

18. The method for manufacturing an electrolytic capacitor according to claim 15, wherein: The capacitor element has a pair of lead terminals extending from the anode foil and the cathode foil, respectively. In the step of sealing the opening of the housing with the sealing body, The pair of lead terminals are respectively fitted into the pair of cutouts of the retainer. The pair of lead terminals fitted in the pair of cutouts are respectively inserted into the pair of insertion holes of the sealing body.

19. A retaining member, characterized in that: The holder is arranged in an electrolytic capacitor including a capacitor element formed by winding an anode foil and a cathode foil via a separator, a case accommodating the capacitor element, and a sealing body sealing an opening of the case. The holding member is disposed between the capacitor element and the sealing body, and holds an antioxidant that is more easily oxidized than the sealing body.

20. The retaining member according to claim 19, characterized in that The antioxidant contains at least one of a photo-oxidant, a vitamin antioxidant, an amine antioxidant, a phenol antioxidant, a phosphorus antioxidant and a carbohydrate antioxidant.

21. The holder according to claim 19 or 20, characterized in that The retainer is made of organic fibers, inorganic fibers or resin fibers as a base material, or is a gel-like medium.

22. The holder according to claim 19 or 20, characterized in that The holder holds a solution containing 2.5 wt % to 20 wt % of α-tocopherol as the antioxidant.

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