Electrolytic capacitor, method for manufacturing the same, and retaining material

Abstract

To provide electrolytic capacitors, a method for manufacturing electrolytic capacitors, and holding materials that improve reliability.SOLUTION: An aluminum electrolytic capacitor has a capacitor element 10 with an anode foil and a cathode foil wound through a separator, a case 11 that houses the capacitor element, a sealing element 12 that seals the opening of the case, and a holding material 14 that is placed between the capacitor element and the sealing element and holds an antioxidant that is more easily oxidized than the sealing element.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an electrolytic capacitor, a method for manufacturing the same, and a holding material.

Background Art

[0002] An electrolytic capacitor has a structure in which an opening of a bottomed cylindrical exterior case that houses a capacitor element in which an anode foil and a cathode foil are wound via a separator is sealed by fitting with a sealing body such as butyl rubber (see, for example, Patent Documents 1 and 2). The capacitor element contains an electrolytic solution, and the characteristics of the electrolytic capacitor deteriorate according to the drying up or liquid leakage of the electrolytic solution.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The sealing body is gradually oxidized by the action of oxygen, electrolytic solution, etc. inside the above-mentioned exterior case. The oxidation of the sealing body becomes remarkable especially when the electrolytic capacitor is used for a long time in a high-temperature environment such as near an engine or near a computer.

[0005] When the sealing body is oxidized and deteriorated, cracks occur in the sealing body, for example, at the contact portion with the case or the insertion hole of the electrode terminal, etc., so there is a risk that the drying up of the electrolytic solution is promoted and the characteristics of the electrolytic capacitor deteriorate.

[0006] For example, Patent Document 2 describes supplying a lipid-soluble antioxidant from the separator to the sealing body. However, this may not effectively suppress oxidation in areas of the sealing body's surface that are not in contact with the separator. As a result, the long-term reliability of the electrolytic capacitor may not be sufficiently ensured.

[0007] Therefore, the present invention has been made in view of the above problems, and aims to provide an electrolytic capacitor that can improve reliability, a method for manufacturing the same, and a retaining material. [Means for solving the problem]

[0008] The electrolytic capacitor of the present invention comprises a capacitor element in which an anode foil and a cathode foil are wound with a separator in between; a case for housing the capacitor element; a sealing body for sealing the opening of the case; and a retaining material disposed between the capacitor element and the sealing body for holding an antioxidant that is more easily oxidized than the sealing body. The capacitor element is provided with a pair of lead terminals extending from the anode foil and the cathode foil, respectively, at its lower part. The sealing body has a pair of insertion holes through which the pair of lead terminals are inserted. The retaining material has a pair of insertion holes into which the pair of lead terminals are inserted.

[0009] In the electrolytic capacitor described above, the retaining material may be a sheet-like member that covers at least a portion of the surface of the sealing body.

[0011] In the electrolytic capacitor described above, the retaining material may have a notch extending from at least one of the pair of insertion holes to the edge of the retaining material.

[0012] In the electrolytic capacitor described above, the diameter of the pair of insertion holes may be 0.5 to 2 times the diameter of the pair of lead terminals.

[0013] Other inventions In the electrolytic capacitor, a pair of lead terminals extending from the anode foil and the cathode foil are provided at the lower part of the capacitor element, the sealing body has a pair of insertion holes through which the pair of lead terminals are inserted, and the retaining material has a pair of notches through which the pair of lead terminals are passed. do.

[0014] In the electrolytic capacitor described above, at least one of the pair of notches may extend to the edge of the retaining material.

[0015] Other types of the present invention In an electrolytic capacitor, a pair of lead terminals extending from the anode foil and the cathode foil are provided at the lower part of the capacitor element, the sealing body has a pair of insertion holes through which the pair of lead terminals are inserted, and the retaining material has a pair of notches that fit into the pair of lead terminals. do.

[0016] In the electrolytic capacitor described above, the separator may extend from the anode foil and the cathode foil toward the retaining material and press against the retaining material.

[0017] In the electrolytic capacitor described above, the antioxidant may include at least one of the following: photo-antioxidants, vitamin antioxidants, amine-based antioxidants, phenol-based antioxidants, phosphorus-based antioxidants, and sugar-based antioxidants.

[0018] In the electrolytic capacitor described above, the retaining material may be based on organic fibers, inorganic fibers, or resin fibers, or it may be a gel-like medium.

[0019] In the electrolytic capacitor described above, the retaining material may be bonded to the sealing body by an adhesive that swells with the electrolyte impregnated into the separator.

[0020] In the electrolytic capacitor described above, the retaining material may hold a solution containing 2.5 (wt%) to 20 (wt%) of α-tocopherol as the antioxidant.

[0021] In the electrolytic capacitor described above, a conductive polymer layer may be formed on the capacitor element.

[0022] The method for manufacturing an electrolytic capacitor according to the present invention includes a step of attaching a sealing body to a capacitor element in which an anode foil and a cathode foil are wound through a separator, via a holding member that holds an antioxidant that is more easily oxidized than the sealing body, and a step of housing the capacitor element in a case and sealing an opening of the case with the sealing body. In the step of attaching the sealing body to the capacitor element via the retaining material, a pair of lead terminals extending from the anode foil and the cathode foil, respectively, are inserted into a pair of insertion holes in the retaining material, and the pair of lead terminals inserted into the pair of insertion holes are then inserted into a pair of through holes in the sealing body. .

[0023] In the above manufacturing method, the capacitor element has a pair of lead-out lead terminals extending from the anode foil and the cathode foil respectively. In the step of sealing the opening of the case with the sealing body, the pair of lead-out lead terminals may be respectively inserted into a pair of insertion holes of the holding member, and the pair of lead-out lead terminals inserted into the pair of insertion holes may be respectively inserted through a pair of insertion through holes of the sealing body.

[0024] Other inventions In the manufacturing method of In the process of attaching the sealing body to the capacitor element via the retaining material, a pair of lead terminals extending from the anode foil and the cathode foil, respectively are respectively passed through a pair of cuts of the holding member, and the pair of lead-out lead terminals passed through the pair of cuts are respectively inserted through a pair of insertion through holes of the sealing body do .

[0025] Further aspects of this invention In the manufacturing method of In the process of attaching the sealing body to the capacitor element via the retaining material, a pair of lead terminals extending from the anode foil and the cathode foil, respectively are respectively fitted into a pair of notches of the holding member, and the pair of lead-out lead terminals fitted into the pair of notches are respectively inserted through a pair of insertion through holes of the sealing body do .

[0026] The holding member according to the present invention is provided in an electrolytic capacitor having a capacitor element in which an anode foil and a cathode foil are wound through a separator, a case for housing the capacitor element, and a sealing body for sealing an opening of the case, and is disposed between the capacitor element and the sealing body, A pair of lead terminals extending from the anode foil and the cathode foil are provided at the bottom. and holds an antioxidant that is more easily oxidized than the sealing body. and has a pair of insertion holes through which the pair of lead terminals are inserted. It has a pair of insertion holes into which the pair of lead terminals described above are inserted, Another retaining material of the present invention has a pair of notches that fit into the pair of lead terminals, respectively, instead of the pair of insertion holes. Yet another retaining material of the present invention has a pair of notches that fit into the pair of lead terminals, respectively, instead of the pair of insertion holes. ​​

[0027] In the above-described retaining material, the antioxidant may include at least one of the following: photo-antioxidants, vitamin antioxidants, amine-based antioxidants, phenol-based antioxidants, phosphorus-based antioxidants, and sugar-based antioxidants.

[0028] In the above-described retaining material, the retaining material may retain a solution containing 2.5 (wt%) to 20 (wt%) of α-tocopherol as the antioxidant. [Effects of the Invention]

[0029] According to the present invention, the reliability of electrolytic capacitors can be improved. [Brief explanation of the drawing]

[0030] [Figure 1] This figure shows an example of an aluminum electrolytic capacitor. [Figure 2] This is a cross-section of the aluminum electrolytic capacitor 1 along line AA in Figure 1. [Figure 3] This is a perspective view showing an example of a capacitor element. [Figure 4] This is an enlarged view of the portion indicated by the symbol P in Figure 3. [Figure 5] (A) is a plan view of a retainer having a pair of insertion holes, (B) is a plan view of a retainer having a pair of notches, (C) is a plan view of a retainer having a pair of cutouts, (D) is a plan view of a retainer having notches extending to the edge of the retainer, and (E) is a plan view of a retainer having a pair of insertion holes and notches extending from each insertion hole to the edge of the retainer. [Figure 6] This is a flowchart illustrating an example of the manufacturing process for aluminum electrolytic capacitors. [Figure 7] This is a perspective view showing an example of the process of attaching a sealing body to a capacitor element via a retaining material. [Figure 8] This perspective view shows another example of the process of attaching a sealing body to a capacitor element via a retaining material. [Figure 9]This figure shows the time change in the capacitance reduction rate of the example and comparative example. [Modes for carrying out the invention]

[0031] [Embodiment] (Configuration of aluminum electrolytic capacitors) Figure 1 shows an example of an aluminum electrolytic capacitor 1. Figure 1 shows the top surface of the aluminum electrolytic capacitor 1 and side The surface is shown. Figure 2 is a cross-section of aluminum electrolytic capacitor 1 along line AA in Figure 1.

[0032] The aluminum electrolytic capacitor 1 comprises a capacitor element 10, a case 11, a sealing body 12, and a retaining material 14. In this example, a conductive polymer hybrid aluminum electrolytic capacitor is specifically mentioned as the aluminum electrolytic capacitor 1, but it is not limited to this. The aluminum electrolytic capacitor 1 is mounted on an electronic circuit board and used, for example, for coupling, decoupling, and smoothing.

[0033] Figure 3 is a perspective view showing an example of a capacitor element 10. The capacitor element 10 is made 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 bottom of the capacitor element 10. A pair of lead wires 110 and 111 extend from the round rod portions of the lead terminals 112 and 113, respectively. The lead terminals 112 and 113 are joined to the anode foil and cathode foil, respectively, by joining means such as crimping, and function as the anode terminal and cathode terminal of the aluminum electrolytic capacitor 1. In this embodiment, a lead-type aluminum electrolytic capacitor 1 is given, but it is not limited to this, and surface-mount type capacitors may also be used.

[0034] The anode foil 101 and cathode foil 102 are valve metals such as aluminum, tantalum, titanium, and niobium, or alloy foils thereof, or vapor-deposited. filmIt is formed from foil with activated carbon formed on its surface. The surface of the anode foil 101 is etched to increase the electrode area. Furthermore, an anodic oxide film is formed on the surface of the anode foil 101. For this reason, the anode foil 101 is insulated from other components. The anodic oxide film functions as a dielectric, thereby enabling the capacitor to function.

[0035] On the other hand, an anodic oxide coating is formed on the surface of the cathode foil 102 as needed. An inorganic layer or a carbon layer may also be formed on the surface of the cathode foil 102; in this case, a conductive polymer, described later, is formed on its surface.

[0036] The separator 103 is wound 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. Note that if the aluminum electrolytic capacitor 1 is not a conductive polymer hybrid capacitor, the conductive polymer is not used.

[0037] The electrolyte can contain polyhydric alcohols, sulfone compounds, lactone compounds, carbonate compounds, diether compounds of polyhydric alcohols, monohydric alcohols, etc. These may be used individually or in combination. Examples of lactone compounds include γ-butyrolactone and γ-valerolactone. Examples of carbonate compounds that can be used as solvents include dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, ethylene carbonate, propylene carbonate, and fluoroethylene carbonate. In particular, ethylene glycol, polyalkylene glycol, γ-butyrolactone, and sulfolane are desirable.

[0038] The electrolyte may contain a solute. As the solute, acidic components, basic components, salts composed of acidic and basic components, nitro compounds, and phenolic compounds can be used. Organic acids, inorganic acids, and composite compounds of organic and inorganic acids can also be used. Examples of organic acids include 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, among other carboxylic acids. Examples of inorganic acids include boric acid, phosphoric acid, phosphorous acid, hypophosphorous acid, phosphoric acid esters, and phosphoric acid diesters. Examples of composite compounds of organic and inorganic acids include borogisalicylic acid, borogisulic acid, boroglyglycolic acid, and others.

[0039] The basic component can be primary to tertiary amines, quaternary ammonium compounds, and quaternary amidinium compounds. Examples of primary to tertiary amines include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, aniline, N,N-diisopropylethylamine, tetramethylethylenediamine, and hexamethylenediamine. Examples of quaternary ammonium compounds include tetramethylammonium, triethylmethylammonium, and tetraethylammonium. Examples of quaternary amidinium compounds include ethyldimethylimidazolinium and tetramethylimidazolinium.

[0040] The case 11 is made of aluminum and has a closed bottom cylindrical shape with a closed top opening. The case 11 covers the capacitor element 10 and the sealing body 12 and functions as the outer casing of the aluminum electrolytic capacitor 1. Note that the shape of the case 11 is not limited to a cylindrical shape, and may also be a rectangular tube shape. In addition, a sleeve or resin layer may be formed on the outside of the case 11.

[0041] Furthermore, the electrolyte may contain an absorbent to absorb hydrogen gas generated inside the case 11. p-nitrobenzyl alcohol is preferred as the absorbent, and the amount added is preferably 0.5 to 1.5 wt% in the electrolyte. This is because if the amount is less than 0.5 wt%, the hydrogen gas absorption effect is small, while if it exceeds 1.5 wt%, the breakdown voltage characteristics of the aluminum electrolytic capacitor 1 may deteriorate.

[0042] The sealing body 12 is a substantially cylindrical member formed from an elastic material such as butyl rubber or vulcanized rubber, or a phenolic resin material. The sealing body 12 is adjacent to the capacitor element 10 via a retaining material 14 that holds an antioxidant, and seals the opening at the bottom of the case 11. In this embodiment, the retaining material 14 is, for example, a sheet-like material, but is not limited thereto. The lead terminals 112 and 113 are inserted through a pair of insertion holes 120 formed in the sealing body 12.

[0043] A throttling groove 11a is formed on the outer circumferential surface of case 11 near the opening, and is recessed compared to other parts. The throttling groove 11a corresponds to the constricted portion of case 11. The sealing body 12 is sufficiently compressed in the throttling groove 11a, thereby sealing the opening of case 11 while maintaining a high degree of airtightness.

[0044] The sealing body 12 is preferably formed from a material such as butyl rubber that has a low swelling rate in relation to the solvent of the electrolyte contained in the separator 103 of the capacitor element 10. For example, if the electrolyte contains ethylene glycol, impurities extracted by the ethylene glycol may cause the sealing body 12 to swell, but by using a butyl rubber sealing body 12, the influence on the characteristics of the aluminum electrolytic capacitor 1 can be reduced. As an example, it is desirable that the swelling rate of butyl rubber is 2 wt% even when immersed in an ethylene glycol solvent at 125 °C for more than 2000 hours.

[0045] However, the sealing body 12 gradually oxidizes due to the action of oxygen in the case 11 and electrolyte in the separator. When the sealing body 12 deteriorates due to oxidation, cracks may form in the sealing body 12, for example, at the contact point with the case 11 or in the insertion hole 120. This can accelerate the drying of the electrolyte, potentially degrading the characteristics of the aluminum electrolytic capacitor 1 and reducing its reliability.

[0046] Therefore, a retaining material 14 is placed between the sealing body 12 and the capacitor element 10. The retaining material 14 holds an antioxidant that is more easily oxidized than the sealing body 12. For this reason, the retaining material 14 suppresses oxidation by supplying the antioxidant to the surface of the sealing body 12. Since the antioxidant supplied by the retaining material 14 is more easily oxidized than the sealing body, oxidation of the sealing body 12 is suppressed while the antioxidant is being oxidized. This improves the reliability of the aluminum electrolytic capacitor 1. The retaining material 14 may also be a gel-like substance or the like.

[0047] Preferably, antioxidants include those with reducing properties, such as photo-antioxidants, vitamin antioxidants, amine antioxidants, phenolic antioxidants, phosphorus antioxidants, and sugar antioxidants. Alternatively, the antioxidant may be a combination of several of the above antioxidants. Vitamins such as α-tocopherol, amine antioxidants such as uric acid, and phenolic antioxidants such as hydroquinone are desirable because their antioxidant function is maintained over a long period.

[0048] As photo-oxidant agents, bis(2,2,6,6-tetramethyl-1-(octyloxy)-4-piperidinyl) ester, 1,1-dimethylethyl hydroperoxide octane 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-tetramethylpiperidine-4-nyl)amino]-6-(2-hydroxyethylamine)-1,3,5-triazine, bis(1,2,2,6,6-pentamethyl-4-piperidinyl) Ru Examples include sebacate and methyl(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate.

[0049] Examples of vitamin antioxidants include tocopherol, tocotrienol, and ascorbic acid.

[0050] Examples of amine-based antioxidants 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).

[0051] Examples of phenolic antioxidants 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-hydroxybenzylthioacetate, bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionic acid][ethylenebis(oxyethylene)], 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.

[0052] Examples of phosphorus-based antioxidants 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, 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, phenyldiisodecyl phosphite, tributyl phosphite, tris(2-ethylhexyl) phosphite, tridecyl phosphite, and trilauryl phosphite.

[0053] Examples of sugar antioxidants include glucose, arabinose, fructose, maltose, lactose, and sorbitol.

[0054] Furthermore, the retaining material 14 preferably uses an organic medium such as cellulose, rayon, and polysaccharides such as agar, and gelatin, or an inorganic fiber such as resin fibers such as polypropylene and polystyrene, or glass fibers containing silicate glass, either alone or in mixtures, as a base material to retain the antioxidant. The retaining material 14 may also be a gel-like substance alone, or a gel-like substance may be formed on the retaining material 14.

[0055] Since the retaining material 14 is a sheet-like member that covers at least a portion of the surface of the sealing body 12, the antioxidant can be easily diffused onto the surface of the sealing body 12 without changing the height of the aluminum electrolytic capacitor 1. The retaining material 14 may be at least partially bonded to the surface of the sealing body 12 by, for example, an adhesive. In this case, if polyethers that swell with the electrolyte are used as the adhesive, the antioxidant can be diffused into the adhesive because of the good penetration of the antioxidant. The thickness of the retaining material 14 is, for example, 5 to 3000 (μm). More specifically, the retaining material 14 should have a thickness of 30 to 500 (μm) so that a sufficient amount of antioxidant can be supplied.

[0056] Furthermore, the retaining material 14 has a pair of insertion holes 140 into which a pair of lead terminals 112 and 113 are inserted, respectively. In the manufacturing process of the aluminum electrolytic capacitor 1, the retaining material 14 is directly attached to the capacitor element 10 in a laminated state on the sealing body 12. At this time, since the lead terminals 112 and 113 are inserted into the insertion holes 140, respectively, at least a portion of the edge of the insertion holes 140 is drawn into the insertion holes 120 of the sealing body 12. As a result, antioxidants are supplied from the retaining material 14 into the insertion holes 120, and oxidation in the insertion holes 120 is effectively suppressed.

[0057] Figure 4 is a figure 2 This is an enlarged view of the part indicated by the symbol P. In the capacitor element 10, the anode foil 101 and the cathode foil 102 are stacked with a separator 103 in between. The separator 103 extends from the anode foil 101 and the cathode foil 102 toward the retaining material 14 and presses against the retaining material 14.

[0058] More specifically, the separator 103 protrudes from the edges of the anode foil 101 and cathode foil 102, and when the sealing body 12 and retaining material 14 are attached to the capacitor element 10 and these are housed in the case 11 during the manufacturing process of the aluminum electrolytic capacitor 1, the separator 13 presses against the surface of the retaining material 14 and becomes bent.

[0059] Therefore, the separator 103 exerts elastic force in the height direction of the aluminum electrolytic capacitor 1, bringing the retaining material 14 into contact with the surface of the sealing body 12. Thus, a sufficient contact area between the surfaces of the retaining material 14 and the sealing body 12 can be ensured, allowing the antioxidant to be suitably diffused onto the surface of the sealing body 12. Note that the separator 103 does not need to be in contact with the retaining material 14 over the entire lower surface of the capacitor element 10; it is sufficient if it is in contact with the retaining material 14 over at least a portion of the lower surface of the capacitor element 10 (for example, 50% or more of the surface area of ​​the sealing body 12). Furthermore, the length of the portion of the separator 103 that protrudes from the anode foil 101 and cathode foil 102 is preferably longer than the distance M between the anode foil 101 and cathode foil 102 and the retaining material, for example, set to 0.1 to 4.0 (mm). More specifically, it is desirable to set it to 0.25 to 4.0 (mm) so that the retaining material 14 is less likely to be damaged.

[0060] Furthermore, the separator 103 may also contain an antioxidant. In this case, the antioxidant is supplied from the separator 103 to the retaining material 14.

[0061] Figure 5(A)~( E Figure 5(A) shows several examples of the retaining material 14. Figure 5(A) is a plan view of the retaining material 14 provided with a pair of insertion holes 140. Each insertion hole 140 has a round shape. At least a portion of the edge of the insertion hole 140 is drawn into the insertion hole 120 of the sealing body 12, and an antioxidant is supplied to the wall surface of the sealing body 12, so it is desirable that the diameter of each insertion hole 140 be smaller than the diameter of the lead terminals 112, 113. For example, it is preferable to set the diameter of the insertion hole 140 to 0.5 to 2 times the diameter of the lead terminals 112, 113. Also, it is desirable that the diameter of the retaining material 14 be the same as the sealing body 12, or larger than the diameter of the sealing body 12, taking into account that the retaining material 14 will bend. Note that even if the diameter of the retaining material 14 is smaller than the diameter of the sealing body 12, the long-term reliability of the aluminum electrolytic capacitor 1 can be improved.

[0062] Since the lead terminals 112 and 113 are inserted into the insertion holes 140, as described above, at least a portion of the edge of the insertion hole 140 is drawn into the insertion hole 120 of the sealing body 12. As a result, antioxidant is supplied from the retaining material 14 into the insertion hole 120, and oxidation inside the insertion hole 120 is effectively suppressed. Note that the shape of the insertion hole 140 is not limited to a circle, but may be triangular or rectangular, for example.

[0063] Figure 5(B) is a plan view of a retaining material 14 provided with a pair of notches 141. Each notch 141 has a cross shape as an example, but is not limited to this. The notches 141 are cuts that extend across the entire thickness of the retaining material 14. Compared to the case in which an insertion hole 140 is provided, the retaining material 14 in this example can hold more antioxidant because the retaining material 14 is not hollowed out.

[0064] Since the lead terminals 112 and 113 are passed through the notches 141, respectively, at least a portion of the edge of the notch 141 is drawn into the insertion hole 120 of the sealing body 12, similar to the case of the insertion hole 140. As a result, antioxidant is supplied from the retaining material 14 into the insertion hole 120, and oxidation within the insertion hole 120 is effectively suppressed.

[0065] Figure 5(C) is a plan view of the retaining member 14 provided with a pair of notches 142. The notches 142, for example, have a shape in which the end of the retaining member 14 is cut out in a roughly U-shape. Each lead terminal 112, 113 is fitted into the notch 142. The notches 142 allow the space through which the lead terminals 112, 113 pass to be set to be larger than the insertion hole 140 and the cutout 141. Therefore, the attachment of the retaining member 14 to the capacitor element is easy in the manufacturing of the aluminum electrolytic capacitor 1.

[0066] Figure 5(D) is a plan view of a retaining member 14 with notches 143 extending to the edge of the retaining member 14. Each notch 143 has a cross shape as an example, but is not limited to this. The notches 143 partially reach the edge of the retaining member 14. Therefore, in the manufacture of the aluminum electrolytic capacitor 1, compared to the notches 141 described above, it is easier to pass the lead terminals 112 and 113 through the notches 143, and the attachment of the retaining member 14 to the capacitor element 10 is easier. Note that the retaining member 14 may be formed such that only one of the pair of notches 141 reaches the edge of the retaining member 14.

[0067] Figure 5(E) is a plan view of a retaining material 14 having a pair of insertion holes 140 and notches 144 extending from each insertion hole 140 to the edge of the retaining material 14. The notches 144 extend linearly from each insertion hole 140 to the edge of the retaining material 14. Therefore, in the manufacturing of the aluminum electrolytic capacitor 1, compared to the case where only insertion holes 140 are provided without notches 144, the lead terminals 112 and 113 can easily pass through the notches 143, making it easier to attach the retaining material 14 to the capacitor element. Note that the notches 144 may be formed in only one of the pair of insertion holes 140.

[0068] (Manufacturing process for aluminum electrolytic capacitors) Figure 6 is a flowchart showing an example of the manufacturing process for aluminum electrolytic capacitor 1. The manufacturing process for aluminum electrolytic capacitor 1 is an example of an electrolytic capacitor manufacturing method.

[0069] First, lead terminals 112 and 113 are connected to the pre-prepared anode foil 101 and cathode foil 102, respectively (Step St1). Crimping is one possible connection method, but it is not limited to this.

[0070] Next, the separator 103, anode foil 101, cathode foil 102, and separator 103 are stacked in this order and wound together, and the outer surface is secured with winding tape to fabricate the capacitor element 10 (Step St2).

[0071] Next, the capacitor element 10 is subjected to a re-constitution treatment (step St3). This repairs defects in the oxide film formed on the surface of the anode foil 101. For the re-constitution treatment, a conversion solution is used in which a solute of 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.

[0072] 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 withdrawn from the conductive polymer dispersion (step St4). In this way, the conductive polymer can be impregnated into the wound body. Note that this step is not performed in the manufacture of a normal aluminum electrolytic capacitor 1, which is not a conductive polymer hybrid aluminum electrolytic capacitor.

[0073] Next, a predetermined amount of electrolyte is impregnated into the capacitor element 10 in a reduced-pressure atmosphere (step St5). The electrolyte may be a conductive polymer dispersion in which a solute is mixed. In other words, a conductive polymer dispersion can be used as the electrolyte. In this case, the impregnation with the electrolyte is carried out simultaneously with the impregnation with the conductive polymer. This completes the capacitor element 10. Furthermore, a solution of an antioxidant similar to that of the retaining material 14 may be added to the electrolyte.

[0074] Next, the sealing body 12 is attached to the capacitor element 10 via the retaining material 14 (step St6). The retaining material 14 is produced by pre-immersing a substrate such as inorganic fibers such as cellulose, polysaccharides, and gelatins, or resin fibers such as polypropylene and polystyrene, in an antioxidant solution. At this time, the solvent of the antioxidant solution may be removed by pre-drying the retaining material 14. Also, the retaining material 14 is, for example For example, The above-mentioned substrate may be produced by immersing it in a dispersion of antioxidant powder or granules in a liquid. Furthermore, the retaining material 14 may be impregnated with the same electrolyte as the separator 103.

[0075] Figure 7 is a perspective view showing an example of the process of attaching a sealing body 12 to a capacitor element 10 via a retaining material 14. In this example, the retaining material 14 shown in Figure 5(A) is used. The sealing body 12 is positioned on the lower surface of the capacitor element 10 via the retaining material 14. At this time, the retaining material 14 may be adhered to the surface of the sealing body 12 with an adhesive such as polyethylene glycol.

[0076] The lead wires 110, 111 and the lead terminals 112, 113 extend downward from the lower surface of the capacitor element 10. Therefore, when placed, the lead wires 110, 111 and the lead terminals 112, 113 are inserted into a pair of insertion holes 140 of the retaining material 14, and further inserted into a pair of through holes 120 of the sealing body 12. Consequently, as described above, at least a portion of the edge of the insertion hole 140 is drawn into the through hole 120 of the sealing body 12, so that antioxidant is supplied from the retaining material 14 into the through hole 120, and oxidation of the wall surface of the through hole 120 is effectively suppressed.

[0077] Figure 8 is a perspective view showing another example of the process of attaching the sealing body 12 to the capacitor element 10 via a retaining material 14. In this example, the retaining material 14 shown in Figure 5(B) is used. The sealing body 12 is positioned on the lower surface of the capacitor element 10 via the retaining material 14. At this time, the lead wires 110, 111 and the lead terminals 112, 113 are pulled into the insertion holes 120 of the sealing body 12 with a resistance lower than that of the insertion holes 140 at the notches 141. The retaining material 14 may also be bonded to the surface of the sealing body 12 with an adhesive such as polyethylene glycol.

[0078] During stacking, the lead terminals 112 and 113 are passed through the notches 141 and then through the pair of insertion holes 120 of the sealing body 12. As a result, as described above, at least a portion of the edge of the notch 141 is drawn into the insertion holes 120 of the sealing body 12. Therefore, antioxidants are supplied from the retaining material 14 into the insertion holes 120, effectively suppressing oxidation of the walls of the insertion holes 120. The attachment of each retaining material 14 shown in Figures 5(D) and 5(E) is carried out in the same manner as described above.

[0079] Furthermore, when using the retaining material 14 shown in Figure 5(C), the lead terminals 112 and 113 are fitted into the notches 142, respectively, and then inserted into the pair of through holes 120 of the sealing body 12 during stacking. For this reason, as described above, the attachment of the retaining material 14 to the capacitor element is easy during the manufacturing of the aluminum electrolytic capacitor 1.

[0080] Refer to Figure 6 again. After the sealing body 12 is attached, the capacitor element 10 is placed in the case 11 and sealed with the sealing body 12 (step St7). In this way, the aluminum electrolytic capacitor 1 is manufactured. [Examples]

[0081] Next, examples of aluminum electrolytic capacitors 1 will be described. Aluminum electrolytic capacitors 1 according to the above embodiment were manufactured in Examples No. 1 to 24. Aluminum electrolytic capacitors 1 in Examples No. 1 to 12 are ordinary electrolytic capacitors that do not contain conductive polymer in the electrolyte, while aluminum electrolytic capacitors 1 in Examples No. 13 to 24 are conductive polymer hybrid aluminum electrolytic capacitors that contain conductive polymer in the electrolyte. For comparison, aluminum electrolytic capacitors in Comparative Examples No. 1 to 3, which do not have a retaining material 14, were also manufactured.

[0082] For each example and comparative example, the rated voltage of the aluminum electrolytic capacitor 1 was 25 (V), and the rated capacitance of the aluminum electrolytic capacitor 1 was 470 (μF). The diameter of the case 11 was 10 (mm), and the height of the case 11 was 10 (mm).

[0083] (Example No. 1) The anode lead terminals 112 were connected to the prepared anode foil 101. The cathode lead terminals 113 were connected to the cathode foil 102, which has a conductive layer on its end face and has undergone a pre-treatment to improve wettability. Then, the separator 103, cathode foil 102, separator 103, and anode foil 101 were laminated in this order, and the capacitor element 10 was fabricated by winding the separator around the lead terminals 112 and 113 and securing the outer surface with winding tape. At this time, the length of the protruding portions of the separator from the anode foil 101 and cathode foil 102 was set to 0.25 mm on both the top and bottom. In addition, cellulose paper with a thickness of 60 μm was prepared as the retaining material 14.

[0084] A γ-butyrolactone solution containing 35 (wt%) 1,2,3,4-tetramethylimidazolinium phthalate was prepared as the electrolyte. The capacitor element 10 was immersed in the electrolyte in a reduced-pressure atmosphere. to A γ-butyrolactone solution containing the antioxidant (±)-α-tocopherol at a concentration of 10 wt%. of The material was impregnated. Here, the retaining material 14 used was the shape shown in Figure 5(A). The retaining material 14 and sealing body 12, through which the lead terminals 112, 113 and lead wires 110, 111 were passed, were attached to the capacitor element 10, and the case 11 was sealed with the sealing body 12 so that the capacitor element 10 was housed in the case 11. In this way, an aluminum electrolytic capacitor 1 was obtained.

[0085] (Example No. 2) The following points differ from the manufacturing method of Example No. 1: The base material of the retaining material 14. to The above electrolyte solution contains (±)-α-tocopherol at a concentration of 10 (wt%). of It was impregnated.

[0086] (Example No. 3) The following points differ from the manufacturing method of Example No. 1: The capacitor element 10 was immersed in an electrolyte containing (±)-α-tocopherol at a concentration of 10 (wt%). After attaching the retaining material 14, which was not impregnated with an antioxidant, to the capacitor element 10, the electrolyte was impregnated into the retaining material 14 from the separator 103 of the capacitor element 10.

[0087] (Example No. 4) The following points differ from the manufacturing method of Example No. 1. The substrate of the retaining material 14 was immersed in a 10 (wt%) γ-butyrolactone solution of (±)-α-tocopherol, and then the γ-butyrolactone solvent was removed from the retaining material 14 by drying.

[0088] (Example No. 5) The following points differ from the manufacturing method of Example No. 1: The base material of the retaining material 14. to A γ-butyrolactone solution containing (±)-α-tocopherol at a concentration of 2.5 wt%. of It was impregnated.

[0089] (Example No. 6) The following points differ from the manufacturing method of Example No. 1: The base material of the retaining material 14. to A γ-butyrolactone solution containing (±)-α-tocopherol at a concentration of 20 (wt%). of It was impregnated.

[0090] (Example No. 7) The following points differ from the manufacturing method of Example No. 1: The base material of the retaining material 14. to γ-butyrolactone solution containing uric acid at a concentration of 10 wt% of It was impregnated.

[0091] (Example No. 8) The following points differ from the manufacturing method of Example No. 1: The base material of the retaining material 14. to A γ-butyrolactone solution containing hydroquinone at a concentration of 10 wt%. of It was impregnated.

[0092] (Example No. 9) The following points differ from the manufacturing method of Example No. 1. The retaining material 14 used was of the shape shown in Figure 5(D).

[0093] (Example No. 10) The following points differ from the manufacturing method of Example No. 1. The retaining material 14 was bonded to the surface of the sealing body 12 with polyethylene glycol, which is an adhesive.

[0094] (Example No. 11) The following points differ from the manufacturing method of Example No. 1: The retaining material 14 was formed on the surface of the sealing body 12 as a gel containing (±)-α-tocopherol.

[0095] (Example No. 12) The following points differ from the manufacturing method of Example No. 1: The separator 103 was impregnated with the same antioxidant as the retaining material 14.

[0096] (Example No. 13) The following points differ from the manufacturing method of Example No. 1. Before immersion in the electrolyte, the capacitor element 10 was re-treated by applying a voltage of 50 (V) in an aqueous ammonium phosphate solution. After washing and drying the capacitor element 10, it was immersed in a dispersion of the conductive polymer PEDOT / PSS (poly(3,4-ethylenedioxythiophene) polystyrene sulfonate) in an atmosphere reduced by -0.97 (MPa) from atmospheric pressure. As the electrolyte, a γ-butyrolactone solution containing 35 (wt%) of 1,2,3,4-tetramethylimidazolinium phthalate was prepared. The capacitor element 10 was immersed in the electrolyte in a reduced-pressure atmosphere. This obtained a conductive polymer hybrid aluminum electrolytic capacitor.

[0097] (Example No. 14) The following points differ from the manufacturing method of Example No. 13: The base material of the retaining material 14. toThe above electrolyte solution contains (±)-α-tocopherol at a concentration of 10 (wt%). of It was impregnated.

[0098] (Example No. 15) The following points differ from the manufacturing method of Example No. 13: The capacitor element 10 was immersed in an electrolyte containing (±)-α-tocopherol at a concentration of 10 (wt%). After attaching the retaining material 14, which was not impregnated with an antioxidant, to the capacitor element 10, the electrolyte was impregnated into the retaining material 14 from the separator 103 of the capacitor element 10.

[0099] (Example No. 16) The following points differ from the manufacturing method of Example No. 13. The substrate of the retaining material 14 was immersed in a 10 (wt%) γ-butyrolactone solution of (±)-α-tocopherol, and then the γ-butyrolactone solvent was removed from the retaining material 14 by drying.

[0100] (Example No. 17) The following points differ from the manufacturing method of Example No. 13: The base material of the retaining material 14. to A γ-butyrolactone solution containing (±)-α-tocopherol at a concentration of 2.5 wt%. of It was impregnated.

[0101] (Example No. 18) The following points differ from the manufacturing method of Example No. 13: The base material of the retaining material 14. to A γ-butyrolactone solution containing (±)-α-tocopherol at a concentration of 20 (wt%). of It was impregnated.

[0102] (Example No. 19) The following points differ from the manufacturing method of Example No. 13: The base material of the retaining material 14. to γ-butyrolactone solution containing uric acid at a concentration of 10 wt% of It was impregnated.

[0103] (Example No. 20) The following points differ from the manufacturing method of Example No. 13: The base material of the retaining material 14. to A γ-butyrolactone solution containing hydroquinone at a concentration of 10 wt%. of It was impregnated.

[0104] (Example No. 21) The following points differ from the manufacturing method of Example No. 13. The retaining material 14 used was of the shape shown in Figure 5(D).

[0105] (Example No. 22) The following points differ from the manufacturing method of Example No. 13: The retaining material 14 was bonded to the surface of the sealing body 12 with polyethylene glycol, which is an adhesive.

[0106] (Example No. 23) The following points differ from the manufacturing method of Example No. 13: The retaining material 14 was formed on the surface of the sealing body 12 as a gel containing (±)-α-tocopherol.

[0107] (Example No. 24) The following points differ from the manufacturing method of Example No. 13: The separator 103 was impregnated with the same antioxidant as the retaining material 14.

[0108] (Comparative Example No. 1) The following points differ from the manufacturing method of Example No. 1: The retaining material 14 is not attached to the capacitor element 10.

[0109] (Comparative Example No. 2) The following points differ from the manufacturing method of Example No. 13: The retaining material 14 is not attached to the capacitor element 10.

[0110] (Comparative Example No. 3) The following points differ from the manufacturing method of Example No. 1: The retaining material 14 is not attached to the capacitor element 10. The separator 103 is impregnated with an antioxidant.

[0111] (evaluation) For each of the aluminum electrolytic capacitors 1 in Examples No. 1 to 24 and the aluminum electrolytic capacitors in Comparative Examples No. 1 to 3, a rated voltage (25 V) was applied in an environment of 130 °C. The capacitance C (μF) was measured 5,000 hours and 8,000 hours after the start of application. The initial value of the capacitance of each aluminum electrolytic capacitor 1 before the evaluation test was defined as Co (μF), and the change in capacitance after 5,000 hours and 8,000 hours from the start of application was defined as ΔC (<0) (μF). The capacitance decrease rate (%) was calculated as ΔC / Co as an evaluation parameter.

[0112] [Table 1]

[0113] Table 1 shows the capacitance reduction rate (%) after 5000 hours and 8000 hours for each aluminum electrolytic capacitor 1 in Examples No. 1 to No. 12, as evaluation results. Furthermore, for aluminum electrolytic capacitor 1 in Examples No. 1 to No. 12 that used (±)-α-tocopherol as an antioxidant, the solution concentration is shown.

[0114] [Table 2]

[0115] Table 2 shows the capacitance reduction rate (%) after 5000 hours and 8000 hours for each aluminum electrolytic capacitor 1 in Examples No. 13 to No. 24, as evaluation results. Furthermore, for aluminum electrolytic capacitor 1 in Examples No. 13 to No. 24 that used (±)-α-tocopherol as an antioxidant, the solution concentration is shown.

[0116] [Table 3]

[0117] table 3The graph shows the capacitance reduction rate (%) after 5000 hours and 8000 hours, which are the evaluation results for each aluminum electrolytic capacitor 1 in Comparative Examples No. 1 to No. 3.

[0118] As can be seen from Tables 1 to 3, the capacitance reduction rate of each aluminum electrolytic capacitor 1 in Examples No. 1 to No. 24 is lower than that of the aluminum electrolytic capacitors in Comparative Examples No. 1 to No. 3. This is because, since a retaining material 14 was provided between the capacitor element 10 and the sealing body 12, the antioxidant held in the retaining material 14 was supplied to the surface of the sealing body 12, and the oxidation of the sealing body 12 was suppressed by the oxidation of the antioxidant.

[0119] Furthermore, comparing the capacitance reduction rate of each aluminum electrolytic capacitor 1 in Examples No. 1 to No. 12 with that of each aluminum electrolytic capacitor 1 in Examples No. 13 to No. 24, the reduction rate is greater for Examples No. 1 to No. 12. 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 conductive polymer is impregnated into the separator 103, oxidation of the sealing body 12 is suppressed more effectively.

[0120] Furthermore, as can be seen from Tables 1 and 2, for aluminum electrolytic capacitor 1 using (±)-α-tocopherol as an antioxidant, the concentration of the solution is preferably 2.5 to 20 (wt%).

[0121] Also, Examples No. 2 and No. 14 The retaining material 14 basis Even when the material was immersed in an electrolyte containing an antioxidant, the rate of capacitance reduction was suppressed compared to Comparative Examples No. 1 to No. 3. Furthermore, even when the antioxidant was impregnated from the separator 103 to the retaining material 14, as in Examples No. 3 and No. 15, the rate of capacitance reduction was suppressed compared to Comparative Examples No. 1 to No. 3. Moreover, even when the solvent of the antioxidant impregnated from the separator 103 to the retaining material 14 was removed, as in Examples No. 4 and No. 16, the rate of capacitance reduction was suppressed compared to Comparative Examples No. 1 to No. 3.

[0122] Furthermore, as in Examples No. 7, 8, 19, and 20, even when antioxidants other than (±)-α-tocopherol were used, the rate of capacitance reduction was suppressed more than in Comparative Examples No. 1 to No. 3. Also, as in Examples No. 9 and No. 21, even when the shape of the retaining material 14 was changed, the rate of capacitance reduction was suppressed more than in Comparative Examples No. 1 to No. 3. Furthermore, as in Examples No. 10 and No. 22, even when the retaining material 14 was bonded to the surface of the sealing body 12 with an adhesive, the rate of capacitance reduction was suppressed more than in Comparative Examples No. 1 to No. 3.

[0123] Furthermore, even when the retaining material 14 was made into a gel, as in Examples No. 11 and No. 23, the rate of capacitance reduction was suppressed more than in Comparative Examples No. 1 to No. 3. Also, even when the separator 103 was impregnated with the same antioxidant as the retaining material 14, as in Examples No. 12 and No. 24, the rate of capacitance reduction was suppressed more than in Comparative Examples No. 1 to No. 3.

[0124] Figure 9 shows the time change in the capacitance reduction rate for Example No. 1 and Comparative Examples No. 1 and No. 3. The horizontal and vertical axes of the graph in Figure 9 represent time (h) and reduction rate (ΔC / Co) (%), respectively.

[0125] The difference in the rate of decrease between Example No. 1 and Comparative Example No. 1 is greater than the difference in the rate of decrease between Example No. 1 and Comparative Example No. 3. The aluminum electrolytic capacitor of Comparative Example No. 3 has an antioxidant impregnated into the separator, which suppresses oxidation of the sealing body and results in a lower rate of decrease than Comparative Example No. 1.

[0126] However, in the case of Comparative Example No. 3, since the antioxidant is contained in the separator along with the electrolyte, it is difficult to achieve a sufficient supply, and because the separator is in direct contact with the sealing body, the electrolyte easily flows into the sealing body, making it difficult to effectively suppress oxidation of the sealing body compared to Example No. 1.

[0127] Thus, according to the aluminum electrolytic capacitor 1, its manufacturing method, and the retaining material 14 of this embodiment, direct contact between the electrolyte contained in the separator 103 within the capacitor element 10 and the sealing body 12 is suppressed, and oxidation 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.

[0128] Although embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention as described in the claims. [Explanation of Symbols]

[0129] 1. Aluminum electrolytic capacitor 10 Capacitor element 11 cases 12 Sealing body 14 Retaining material 101 Anode foil 102 Cathode Foil 103 Separator 112,113 Lead terminals 140 Insertion holes 141, 143, 144 cuts 142 Notches

Claims

1. A capacitor element in which an anode foil and a cathode foil are wound with a separator in between, A case for housing the aforementioned capacitor element, A sealing body that seals the opening of the case, The capacitor element and the sealing body are disposed between them and a retaining material which holds an antioxidant that is more easily oxidized than the sealing body, A pair of lead terminals extending from the anode foil and the cathode foil are provided at the lower part of the capacitor element. The sealing body has a pair of insertion holes through which the pair of lead terminals are inserted, The electrolytic capacitor is characterized in that the retaining material has a pair of insertion holes into which the pair of lead terminals are each inserted.

2. A capacitor element in which an anode foil and a cathode foil are wound with a separator in between, A case for housing the aforementioned capacitor element, A sealing body that seals the opening of the case, The capacitor element and the sealing body are disposed between them and a retaining material which holds an antioxidant that is more easily oxidized than the sealing body, A pair of lead terminals extending from the anode foil and the cathode foil are provided at the lower part of the capacitor element. The sealing body has a pair of insertion holes through which the pair of lead terminals are inserted, The electrolytic capacitor is characterized in that the retaining material has a pair of notches through which the pair of lead terminals pass.

3. A capacitor element in which an anode foil and a cathode foil are wound with a separator in between, A case for housing the aforementioned capacitor element, A sealing body that seals the opening of the case, The capacitor element and the sealing body are disposed between them and a retaining material which holds an antioxidant that is more easily oxidized than the sealing body, A pair of lead terminals extending from the anode foil and the cathode foil are provided at the lower part of the capacitor element. The sealing body has a pair of insertion holes through which the pair of lead terminals are inserted, The electrolytic capacitor is characterized in that the retaining material has a pair of notches that fit into the pair of lead terminals.

4. The electrolytic capacitor according to any one of claims 1 to 3, characterized in that the retaining material is a sheet-like member that covers at least a portion of the surface of the sealing body.

5. The electrolytic capacitor according to claim 1, characterized in that the retaining material has a notch extending from at least one of the pair of insertion holes to the edge of the retaining material.

6. The electrolytic capacitor according to claim 1, 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.

7. The electrolytic capacitor according to claim 2, characterized in that at least one of the pair of notches extends to the edge of the retaining material.

8. The electrolytic capacitor according to any one of claims 1 to 3, characterized in that the separator extends from the anode foil and the cathode foil toward the retaining material and presses against the retaining material.

9. The electrolytic capacitor according to any one of claims 1 to 3, characterized in that the antioxidant comprises at least one of the following: a photo-antioxidant, a vitamin-based antioxidant, an amine-based antioxidant, a phenol-based antioxidant, a phosphorus-based antioxidant, and a sugar-based antioxidant.

10. The electrolytic capacitor according to any one of claims 1 to 3, characterized in that the retaining material is based on organic fibers, inorganic fibers, or resin fibers, or is a gel-like medium.

11. The electrolytic capacitor according to any one of claims 1 to 3, characterized in that the retaining material is bonded to the sealing body with an adhesive that swells with the electrolyte impregnated in the separator.

12. The electrolytic capacitor according to any one of claims 1 to 3, characterized in that the retaining material holds a solution containing 2.5 (wt%) to 20 (wt%) of α-tocopherol as the antioxidant.

13. The electrolytic capacitor according to any one of claims 1 to 3, characterized in that a conductive polymer layer is formed on the capacitor element.

14. A step of attaching a sealing body to a capacitor element in which anode foil and cathode foil are wound via a separator, via a retaining material that holds an antioxidant that is more easily oxidized than the sealing body, The process includes housing the capacitor element in a case and sealing the opening of the case with the sealing body, In the process of attaching the sealing body to the capacitor element via the retaining material, A pair of lead terminals extending from the anode foil and the cathode foil are respectively inserted into a pair of insertion holes in the retaining material. A method for manufacturing an electrolytic capacitor, characterized by inserting the pair of lead terminals inserted into the pair of insertion holes into the pair of insertion holes of the sealing body.

15. A step of attaching a sealing body to a capacitor element in which anode foil and cathode foil are wound via a separator, via a retaining material that holds an antioxidant that is more easily oxidized than the sealing body, The process includes housing the capacitor element in a case and sealing the opening of the case with the sealing body, In the process of attaching the sealing body to the capacitor element via the retaining material, The pair of lead terminals extending from the anode foil and the cathode foil are respectively passed through the pair of notches in the retaining material. A method for manufacturing an electrolytic capacitor, characterized by inserting the pair of lead terminals, which have been passed through the pair of notches, into the pair of insertion holes in the sealing body.

16. A step of attaching a sealing body to a capacitor element in which anode foil and cathode foil are wound via a separator, via a retaining material that holds an antioxidant that is more easily oxidized than the sealing body, The process includes housing the capacitor element in a case and sealing the opening of the case with the sealing body, In the process of attaching the sealing body to the capacitor element via the retaining material, The pair of lead terminals extending from the anode foil and the cathode foil are respectively fitted into the pair of notches in the retaining material. A method for manufacturing an electrolytic capacitor, characterized by inserting the pair of lead terminals, which are fitted into the pair of notches, into the pair of insertion holes in the sealing body.

17. In the step of attaching the sealing body to the capacitor element via the retaining material, A method for manufacturing an electrolytic capacitor according to any one of claims 14 to 16, characterized in that the retaining material is bonded to the sealing body with an adhesive that swells with the electrolyte impregnated in the separator.

18. An electrolytic capacitor comprising a capacitor element in which an anode foil and a cathode foil are wound around a separator, and a pair of lead terminals extending from the anode foil and the cathode foil are provided at the bottom, a case for housing the capacitor element, and a sealing body that seals the opening of the case and has a pair of through holes through which the pair of lead terminals are inserted, is provided, A retaining material is disposed between the capacitor element and the sealing body, having a pair of insertion holes into which the pair of lead terminals are inserted, and characterized in that it holds an antioxidant that is more susceptible to oxidation than the sealing body.

19. An electrolytic capacitor comprising a capacitor element in which an anode foil and a cathode foil are wound around a separator, and a pair of lead terminals extending from the anode foil and the cathode foil are provided at the bottom, a case for housing the capacitor element, and a sealing body that seals the opening of the case and has a pair of through holes through which the pair of lead terminals are inserted, is provided, A retaining material is provided, which is positioned between the capacitor element and the sealing body, has a pair of notches through which the pair of lead terminals pass, and is characterized by holding an antioxidant that is more susceptible to oxidation than the sealing body.

20. An electrolytic capacitor comprising a capacitor element in which an anode foil and a cathode foil are wound around a separator, and a pair of lead terminals extending from the anode foil and the cathode foil are provided at the bottom, a case for housing the capacitor element, and a sealing body that seals the opening of the case and has a pair of through holes through which the pair of lead terminals are inserted, is provided, A retaining material is provided, which is positioned between the capacitor element and the sealing body, has a pair of notches that fit into the pair of lead terminals, and is characterized by holding an antioxidant that is more susceptible to oxidation than the sealing body.

21. The retaining material according to any one of claims 18 to 20, characterized in that the antioxidant comprises at least one of the following: a photo-antioxidant, a vitamin antioxidant, an amine-based antioxidant, a phenol-based antioxidant, a phosphorus-based antioxidant, and a sugar-based antioxidant.

22. A retaining material according to any one of claims 18 to 20, characterized in that it uses organic fibers, inorganic fibers, or resin fibers as a base material, or is a gel-like medium.

23. The retaining material according to any one of claims 18 to 20, characterized in that the retaining material holds a solution containing 2.5 (wt%) to 20 (wt%) of α-tocopherol as the antioxidant.

24. The retaining material according to any one of claims 18 to 20, characterized in that it is adhered to the sealing body by an adhesive that swells with the electrolyte impregnated in the separator.

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