Electrolytic capacitor, method for manufacturing the same, and holding 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 manufacturing method thereof, and a supporting material. [Background technology]

[0002] The electrolytic capacitor has a structure in which a capacitor element in the form of an anode foil and a cathode foil wound with a separator interposed therebetween is housed in a cylindrical exterior case with a bottom, and the opening of the case is fitted and sealed with a sealing material such as butyl rubber (see, for example, Patent Documents 1 and 2). The capacitor element contains an electrolyte, and the characteristics of the electrolytic capacitor deteriorate as the electrolyte dries up or leaks. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2017 / 090241 [Patent Document 2] International Publication No. 2020 / 059091 Summary of the Invention [Problem to be solved by the invention]

[0004] The sealant is gradually oxidized by the action of oxygen, electrolyte, etc. in the exterior case. Oxidation of the sealant becomes noticeable when the electrolytic capacitor is used for a long period of time in a high-temperature environment, such as near an engine or a computer.

[0005] If the sealant deteriorates due to oxidation, cracks may occur in the sealant, for example, at the contact portion with the case or in the insertion hole of the electrode terminal, which may accelerate drying up of the electrolyte and cause deterioration of the characteristics of the electrolytic capacitor.

[0006] For example, Patent Document 2 describes the supply of an oil-soluble antioxidant from a separator to a sealing body. However, there is a risk that the oxidation of the surface of the sealing body that is not in contact with the separator cannot be effectively suppressed. As a result, there is a risk that the long-term reliability of the electrolytic capacitor cannot be sufficiently ensured.

[0007] The present invention has been made in consideration of the above problems, and an object of the present invention is to provide an electrolytic capacitor that can improve reliability, a manufacturing method thereof, and a supporting material. [Means for solving the problem]

[0008] The electrolytic capacitor of the present invention is characterized by comprising a capacitor element in which an anode foil and a cathode foil are wound with a separator between them, a case for accommodating the capacitor element, a sealant for sealing an opening of the case, and a retaining material that is disposed between the capacitor element and the sealant and retains an antioxidant that is more easily oxidized than the sealant.

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

[0010] In the above electrolytic capacitor, a pair of lead terminals extending from the anode foil and the cathode foil, respectively, may be provided on the lower part of the capacitor element, the sealing body may have a pair of insertion holes through which the pair of lead terminals are respectively inserted, and the retaining material may have a pair of insertion holes through which the pair of lead terminals are respectively inserted.

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

[0012] In the above electrolytic capacitor, the pair of insertion holes may have a diameter that is 0.5 to 2 times the diameter of the pair of lead terminals.

[0013] In the above electrolytic capacitor, a pair of lead terminals extending from the anode foil and the cathode foil, respectively, may be provided on a lower part of the capacitor element, the sealing body may have a pair of insertion holes through which the pair of lead terminals are respectively inserted, and the retaining material may have a pair of notches through which the pair of lead terminals are respectively inserted.

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

[0015] In the above electrolytic capacitor, a pair of lead terminals extending from the anode foil and the cathode foil, respectively, may be provided on the lower part of the capacitor element, the sealing body may have a pair of insertion holes through which the pair of lead terminals are respectively inserted, and the retaining material may have a pair of notches which respectively fit into the pair of lead terminals.

[0016] In the above electrolytic capacitor, the separator may extend beyond the anode foil and the cathode foil toward the holding material and be pressed against the holding material.

[0017] In the electrolytic capacitor, the antioxidant may include at least one of a photoantioxidant, a vitamin antioxidant, an amine-based antioxidant, a phenol-based antioxidant, a phosphorus-based antioxidant, and a sugar-based antioxidant.

[0018] In the above electrolytic capacitor, the support material may be made of organic fibers, inorganic fibers, or resin fibers as a base material, or may be a gel medium.

[0019] In the above electrolytic capacitor, the holding material may be adhered to the sealing body by an adhesive that swells with the electrolyte impregnated in the separator.

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

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

[0022] The method for manufacturing an electrolytic capacitor of the present invention is characterized by including the steps of: attaching a seal to a capacitor element having an anode foil and a cathode foil wound with a separator therebetween, via a retaining material that retains an antioxidant that is more easily oxidized by the seal; and housing the capacitor element in a case and sealing an opening of the case with the seal.

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

[0024] In the above manufacturing method, the capacitor element may have a pair of pull-out lead terminals extending from the anode foil and the cathode foil, respectively, and in the step of sealing the opening of the case with the sealing body, the pair of pull-out lead terminals may be passed through a pair of notches in the holding material, respectively, and the pair of pull-out lead terminals passed through the pair of notches may be inserted into a pair of insertion holes in the sealing body, respectively.

[0025] In the above manufacturing method, the capacitor element may have a pair of pull-out lead terminals extending from the anode foil and the cathode foil, respectively, and in a step of sealing the opening of the case with the sealing body, the pair of pull-out lead terminals may be respectively fitted into a pair of cutouts in the retaining material, and the pair of pull-out lead terminals fitted into the pair of cutouts may be respectively inserted into a pair of insertion holes in the sealing body.

[0026] The retaining material of the present invention is provided in an electrolytic capacitor having a capacitor element in which an anode foil and a cathode foil are wound with a separator between them, a case for accommodating the capacitor element, and a sealing body for sealing an opening of the case, and is characterized in that the retaining material is disposed between the capacitor element and the sealing body and retains an antioxidant that is easily oxidized by the sealing body.

[0027] In the above-mentioned retention material, the antioxidant may include at least one of a photoantioxidant, a vitamin antioxidant, an amine-based antioxidant, a phenol-based antioxidant, a phosphorus-based antioxidant, and a sugar-based antioxidant.

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

[0029] According to the present invention, the reliability of the electrolytic capacitor can be improved. [Brief description of the drawings]

[0030] [Figure 1] FIG. 1 is a diagram illustrating an example of an aluminum electrolytic capacitor. [Diagram 2] 2 is a cross-section of the aluminum electrolytic capacitor 1 taken along line AA in FIG. [Diagram 3] FIG. 2 is a perspective view showing an example of a capacitor element. [Figure 4] FIG. 4 is an enlarged view of a portion indicated by the symbol P in FIG. [Diagram 5] (A) is a plan view of a retaining material having a pair of insertion holes, (B) is a plan view of a retaining material having a pair of notches, (C) is a plan view of a retaining material having a pair of notches, (D) is a plan view of a retaining material having notches extending to the edge of the retaining material, and (E) is a plan view of a retaining material having a pair of insertion holes and notches extending from each insertion hole to the edge of the retaining material. [Figure 6]1 is a flowchart showing an example of a manufacturing process for an aluminum electrolytic capacitor. [Figure 7] 11 is a perspective view showing an example of a process for attaching a sealing body to a capacitor element via a holding material. FIG. [Figure 8] 13 is a perspective view showing another example of a process for attaching a sealing body to a capacitor element via a retaining material. FIG. [Figure 9] FIG. 13 is a diagram showing the change over time in the rate of decrease in capacitance in an example and a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] [Embodiment] (Aluminum electrolytic capacitor composition) Fig. 1 is a diagram showing an example of an aluminum electrolytic capacitor 1. Fig. 1 shows an upper surface and a rough surface of the aluminum electrolytic capacitor 1. Fig. 2 is a cross-section of the aluminum electrolytic capacitor 1 taken along line AA in Fig. 1.

[0032] The aluminum electrolytic capacitor 1 has a capacitor element 10, a case 11, a sealing body 12, and a holding material 14. In this example, a conductive polymer hybrid aluminum electrolytic capacitor is particularly given as the aluminum electrolytic capacitor 1, but is not limited thereto. The aluminum electrolytic capacitor 1 is mounted on an electronic circuit board and is used for, for example, coupling, decoupling, smoothing, and the like.

[0033] 3 is a perspective view 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, 113 extend from the lower part of the capacitor element 10. A pair of lead wires 110, 111 extend from the round bar parts of the lead terminals 112, 113. The lead terminals 112, 113 are joined to the anode foil and the cathode foil by a joining means such as crimping, and function as the anode terminal and the cathode terminal of the aluminum electrolytic capacitor 1. Note that, although a lead type aluminum electrolytic capacitor 1 is exemplified in this embodiment, the present invention is not limited thereto, and the capacitor may be of a surface mount type or the like.

[0034] The anode foil 101 and the cathode foil 102 are made of valve metals such as aluminum, tantalum, titanium, and niobium, or alloy foils thereof, or evaporated foils or foils with activated carbon on the surface. The surface of the anode foil 101 is etched to increase the electrode area. In addition, an anodized film is formed on the surface of the anode foil 101. This insulates the anode foil 101 from other components. The anodized film functions as a dielectric, thereby providing the function of a capacitor.

[0035] On the other hand, an anodized coating is formed, if necessary, on the surface of the cathode foil 102. An inorganic layer or a carbon layer may be formed on the surface of the cathode foil 102, and in this case, a conductive polymer, which will be described later, is formed on the surface.

[0036] Separator 103 is wound in a state sandwiched between anode foil 101 and cathode foil 102. Separator 103 is made of at least one material selected from cellulose, rayon, glass fiber, and the like. Separator 103 is impregnated with an electrolyte and a conductive polymer. Note that if aluminum electrolytic capacitor 1 is not a conductive polymer hybrid capacitor, a conductive polymer is not used.

[0037] The electrolyte may contain polyhydric alcohol, sulfone compound, lactone compound, carbonate compound, diether compound of polyhydric alcohol, monohydric alcohol, etc. These may be used alone or in combination. As the lactone compound, γ-butyrolactone, γ-valerolactone, etc. may be used. As the carbonate compound, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, ethylene carbonate, propylene carbonate, fluoroethylene carbonate, etc. may be included as a solvent. In particular, it is preferable to use ethylene glycol, polyalkylene glycol, γ-butyrolactone, and sulfolane.

[0038] The electrolyte may contain a solute. As the solute, an acid component, a base component, a salt of an acid component and a base component, a nitro compound, a phenol compound, and the like can be used. In addition, an organic acid, an inorganic acid, and a complex compound of an organic acid and an inorganic acid can also be used. As the organic acid, a carboxylic acid 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 can be used. As the inorganic acid, boric acid, phosphoric acid, phosphorous acid, hypophosphorous acid, phosphoric acid ester, and phosphoric acid diester can be used. As the complex compound of an organic acid and an inorganic acid, borodisalicylic acid, borodisalic acid, borodiglycolic acid, and the like can be used.

[0039] The base component may be a primary to tertiary amine, a quaternary ammonium, or a quaternary amidinium. Examples of the primary to tertiary amine that may be used include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, aniline, N,N-diisopropylethylamine, tetramethylethylenediamine, and hexamethylenediamine. Examples of the quaternary ammonium that may be used include tetramethylammonium, triethylmethylammonium, and tetraethylammonium. Examples of the quaternary amidinium that may be used include ethyldimethylimidazolinium and tetramethylimidazolinium.

[0040] Case 11 is made of aluminum and has a cylindrical shape with a closed top opening. Case 11 covers capacitor element 10 and sealing body 12, and functions as an exterior of aluminum electrolytic capacitor 1. The shape of case 11 is not limited to a cylindrical shape, and may be a square tube shape. Also, a sleeve or a resin layer may be formed on the outside of case 11.

[0041] The electrolyte may also contain an absorbent that absorbs hydrogen gas generated inside the case 11. As the absorbent, p-nitrobenzyl alcohol is suitable, and the amount of the absorbent added to the electrolyte is preferably 0.5 to 1.5 wt %. This is because if it is less than 0.5 wt %, the hydrogen gas absorption effect is small, whereas if it exceeds 1.5 wt %, the voltage resistance characteristics of the aluminum electrolytic capacitor 1 may be reduced.

[0042] The sealing body 12 is a generally cylindrical member formed of 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 retains an antioxidant, and seals the opening at the bottom of the case 11. The retaining material 14 in this embodiment is, for example, a sheet-like material, but is not limited to this. The lead terminals 112 and 113 are inserted into a pair of insertion holes 120 formed in the sealing body 12.

[0043] A throttle groove 11a that is recessed from other parts is formed on the outer peripheral surface near the opening of case 11. Throttle groove 11a corresponds to the constricted part of case 11. Sealing body 12 is sufficiently compressed by throttle groove 11a to seal the opening of case 11 while maintaining high airtightness.

[0044] It is preferable that sealing body 12 is made of a material such as butyl rubber that has a small swelling rate in the solvent of the electrolyte contained in separator 103 of capacitor element 10. For example, if the electrolyte contains ethylene glycol, impurities extracted by the ethylene glycol may cause sealing body 12 to swell, but by using a butyl rubber sealing body 12, it is possible to reduce the effect on the characteristics of aluminum electrolytic capacitor 1. As an example of the characteristics of butyl rubber, it is desirable that the swelling rate is 2 (wt%) even when immersed in an ethylene glycol solvent at 125 (°C) for 2000 hours or more.

[0045] However, sealing body 12 gradually oxidizes due to the action of oxygen in case 11 and the electrolyte in the separator. If sealing body 12 deteriorates due to oxidation, cracks will occur in sealing body 12, for example, in the contact portion with case 11 or in insertion hole 120, which may accelerate drying up of the electrolyte and deteriorate the characteristics of aluminum electrolytic capacitor 1, resulting in a risk of reduced reliability.

[0046] Therefore, the retaining material 14 is disposed between the sealing body 12 and the capacitor element 10. The retaining material 14 retains an antioxidant that is more easily oxidized than the sealing body 12. For this reason, the retaining material 14 suppresses the oxidation of the antioxidant by supplying it 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 be a gel-like single body, etc.

[0047] The antioxidant preferably includes those having a reducing action, such as photo-oxidants, vitamin antioxidants, amine-based antioxidants, phenol-based antioxidants, phosphorus-based antioxidants, and sugar-based antioxidants. The antioxidant may be a combination of two or more of the above-mentioned antioxidants. Vitamins such as α-tocopherol, amine-based antioxidants such as uric acid, and phenol-based antioxidants such as hydroquinone are preferable because they maintain their antioxidant function for a long period of time.

[0048] Examples of photo-oxidants include bis(2,2,6,6-tetramethyl-1-(octyloxy)-4-piperidinyl)ester, 1,1-dimethylethyl hydroperoxide octane reactant, 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-tetramethylpiperidin-4-yl)amino]-6-(2-hydroxyethylamine)-1,3,5-triazine, bis(1,2,2,6,6-pentamethyl-4-piperidinyi)sebacate, and methyl(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate.

[0049] Vitamin antioxidants include tocopherols, tocotrienols, and ascorbic acid.

[0050] Examples of the amine 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][ethylene bis(oxyethylene)], thiodiethylene bis[(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 the 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- and di-mixed nonylphenyl)phosphite, diphenyl acid phosphite, 2,2'-methylenebis(4,6-di-tert-butylphenyl)octyl phosphite, diphenyl decyl phosphite, diphenyl octyl phosphite, bis(nonylphenyl)pentaerythritol phosphite, phenyl diisodecyl phosphite, tributyl phosphite, tris(2-ethylhexyl)phosphite, tridecyl phosphite, and trilauryl phosphite.

[0053] Sugar antioxidants include glucose, arabinose, fructose, maltose, lactose, and sorbitol.

[0054] The retention material 14 preferably uses, as a base material, an organic medium such as celluloses, polysaccharides such as rayon, and agar, and gelatins, or inorganic fibers such as resin fibers such as polypropylene and polystyrene, and glass fibers containing silicate glass, either alone or in combination, to retain the antioxidant. The retention material 14 may be a gel-like substance, or a gel-like substance may be formed in the retention material 14.

[0055] The retaining material 14 is a sheet-like member that covers at least a portion of the surface of the sealing body 12, and therefore 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 adhered 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 has good permeability and can diffuse through the adhesive. The thickness of the retaining material 14 is, for example, 5 to 3000 (μm). More specifically, the retaining material 14 may have a thickness of 30 to 500 (μm) that allows the antioxidant to be supplied sufficiently.

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

[0057] Fig. 4 is an enlarged view of a portion indicated by symbol P in Fig. 3. In capacitor element 10, anode foil 101 and cathode foil 102 are laminated with separator 103 interposed between them. Separator 103 extends beyond anode foil 101 and cathode foil 102 toward holding material 14 and is pressed against holding material 14.

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

[0059] Therefore, the separator 103 exerts an elastic force in the height direction of the aluminum electrolytic capacitor 1 to bring the holding material 14 into contact with the surface of the sealing body 12. Therefore, the contact area between the holding material 14 and the surface of the sealing body 12 can be sufficiently secured, and the antioxidant can be suitably diffused onto the surface of the sealing body 12. The separator 103 does not need to be pressed against the holding material 14 over the entire lower surface of the capacitor element 10, but only needs to be pressed against the holding material 14 over at least a part of the lower surface of the capacitor element 10 (for example, 50(%) or more 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 longer than the distance M between the anode foil 101 and the cathode foil 102 and the holding material, and is preferably set to, for example, 0.1 to 4.0 (mm). More specifically, it is desirable to set the length to 0.25 to 4.0 (mm) at which the holding material 14 is less likely to be damaged.

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

[0061] 5(A) to (D) show several examples of the holding material 14. FIG. 5(A) is a plan view of the holding material 14 provided with a pair of insertion holes 140. Each insertion hole 140 has a round shape. Since the antioxidant is drawn into the insertion hole 140 of the sealing body 12 and supplied to the wall surface of the sealing body 12, it is preferable that the diameter of each insertion hole 140 is smaller than the diameter of the lead terminals 112 and 113. For example, it is preferable that the diameter of the insertion hole 140 is set to 0.5 to 2 times the diameter of the lead terminals 112 and 113. In addition, it is preferable that the diameter of the holding material 14 is the same as that of the sealing body 12, or larger than that of the sealing body 12 in consideration of the bending of the holding material 14. Note that even if the diameter of the holding material 14 is smaller than that of the sealing body 12, the long-term reliability of the aluminum electrolytic capacitor 1 can be improved.

[0062] Since the lead terminals 112, 113 are inserted into the insertion holes 140, as described above, at least a portion of the edge of the insertion holes 140 is drawn into the insertion holes 120 of the sealing body 12. Therefore, an antioxidant is supplied from the holding material 14 into the insertion holes 120, effectively suppressing oxidation within the insertion holes 120. The shape of the insertion holes 140 is not limited to a circle, and may be, for example, a triangular or rectangular shape.

[0063] 5(B) is a plan view of the retention material 14 provided with a pair of notches 141. Each notch 141 has a cross shape, for example, but is not limited to this. The notch 141 is a cut that runs through the entire thickness of the retention material 14. Compared to the case where the retention material 14 has the insertion holes 140, the retention material 14 of this example is not hollowed out, so it can hold more antioxidants.

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

[0065] 5(C) is a plan view of holding material 14 provided with a pair of notches 142. As an example, notches 142 have a shape obtained by cutting out an end of holding material 14 into a substantially U-shape. Each of pull-out lead terminals 112, 113 is fitted into notch 142. Cutout 142 can be set to a space through which pull-out lead terminals 112, 113 pass larger than insertion hole 140 and cutout 141. This makes it easy to attach holding material 14 to a capacitor element in the manufacture of aluminum electrolytic capacitor 1.

[0066] 5(D) is a plan view of the holding material 14 having the notches 143 extending to the edge of the holding material 14. As an example, each of the notches 143 has a cross shape, but is not limited to this. The notches 143 partially reach the edge of the holding material 14. Therefore, in manufacturing the aluminum electrolytic capacitor 1, compared to the above-mentioned notch 141, it is easier to pass the lead terminals 112, 113 through the notches 143, and the holding material 14 is easier to attach to the capacitor element 10. Note that the holding material 14 may be formed so that only one of the pair of notches 141 reaches the edge of the holding material 14.

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

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

[0069] First, lead terminals 112, 113 are connected to anode foil 101 and cathode foil 102, which have been prepared in advance (step St1). Connection means include, but are not limited to, crimping.

[0070] Next, separator 103, anode foil 101, cathode foil 102, and separator 103 are layered in this order and wound, and the outer surface is fixed with a stop tape to produce capacitor element 10 (step St2).

[0071] Next, a chemical re-treatment is applied to the capacitor element 10 (step St3), which repairs defects in the oxide film formed on the surface of the anode foil 101. For the chemical re-treatment, a chemical 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.

[0072] Next, in a reduced pressure atmosphere, the capacitor element 10 is immersed in a conductive polymer dispersion liquid containing water and an organic solvent, and then the capacitor element 10 is pulled out of the conductive polymer dispersion liquid (step St4). In this manner, the wound body can be impregnated with the conductive polymer. 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, in a reduced pressure atmosphere, a predetermined amount of electrolytic solution is impregnated into the capacitor element 10 (step St5). The electrolytic solution may be a conductive polymer dispersion liquid mixed with a solute. In other words, a conductive polymer dispersion liquid can be used as the electrolytic solution. In this case, the impregnation with the electrolytic solution is carried out simultaneously with the impregnation with the conductive polymer. This completes the capacitor element 10. The electrolytic solution may also contain a solution of an antioxidant similar to that of the support material 14.

[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, for example, by immersing a base material such as inorganic fibers such as celluloses, polysaccharides, and gelatins, or resin fibers such as polypropylene and polystyrene, in a solution of an antioxidant. At this time, the retaining material 14 may be dried in advance to remove the solvent of the antioxidant solution. The retaining material 14 may also be produced by immersing the above-mentioned base material in a dispersion liquid in which, for example, antioxidant powder or particles are dispersed in a liquid. Furthermore, the retaining material 14 may be impregnated with the same electrolyte solution as the separator 103.

[0075] Fig. 7 is a perspective view showing an example of a process for attaching sealing body 12 to capacitor element 10 via holding material 14. In this example, holding material 14 shown in Fig. 5(A) is used. Sealing body 12 is placed on the lower surface of capacitor element 10 via holding material 14. At this time, holding material 14 may be adhered to the surface of 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 bottom surface of the capacitor element 10. Therefore, during arrangement, the lead wires 110, 111 and the lead terminals 112, 113 are inserted into a pair of insertion holes 140 of the holding material 14, respectively, and are further inserted into a pair of insertion holes 120 of the sealing body 12. Therefore, 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, so that an antioxidant is supplied from the holding material 14 into the insertion hole 120, and oxidation of the wall surface of the insertion hole 120 is effectively suppressed.

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

[0078] During stacking, the lead terminals 112, 113 are passed through the notches 141, and then through a pair of insertion holes 120 of the sealing body 12. Therefore, as described above, at least a portion of the edge of the notch 141 is drawn into the insertion hole 120 of the sealing body 12. Therefore, an antioxidant is supplied from the holding material 14 into the insertion hole 120, and oxidation of the wall surface of the insertion hole 120 is effectively suppressed. The attachment of each holding material 14 shown in Figures 5(D) and 5(E) is performed in a similar manner to the above.

[0079] 5(C) is used, during lamination, lead terminals 112, 113 are fitted into notches 142, and are further inserted into a pair of insertion holes 120 of sealing body 12. Therefore, as described above, attachment of holding material 14 to the capacitor elements in manufacturing aluminum electrolytic capacitor 1 is easy.

[0080] 6 again, after sealing body 12 is attached, capacitor element 10 is housed in case 11 and sealed with sealing body 12 (step St7). In this manner, aluminum electrolytic capacitor 1 is manufactured. EXAMPLES

[0081] Next, examples of the aluminum electrolytic capacitor 1 will be described. Aluminum electrolytic capacitors 1 of Examples 1 to 24 according to the above embodiment were fabricated. The aluminum electrolytic capacitors 1 of Examples 1 to 12 are normal electrolytic capacitors whose electrolytic solution does not contain a conductive polymer, and the aluminum electrolytic capacitors 1 of Examples 13 to 24 are conductive polymer hybrid aluminum electrolytic capacitors whose electrolytic solution contains a conductive polymer. For comparison, aluminum electrolytic capacitors of Comparative Examples 1 to 3 that do not include a retaining material 14 were also fabricated.

[0082] In each of the examples and comparative examples, 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 terminal 112 was connected to the prepared anode foil 101. The cathode lead terminal 113 was connected to the cathode foil 102, which had a conductor layer on its end surface and was pretreated to improve wettability. Thereafter, the separator 103, the cathode foil 102, the separator 103, and the anode foil 101 were laminated in this order, and the lead terminals 112 and 113 were wound while being rolled, and the outer surface was fixed with a stopper tape to produce the capacitor element 10. At this time, the length of the separator protruding from the anode foil 101 and the cathode foil 102 was 0.25 (mm) on both the top and bottom. In addition, cellulose paper with a thickness of 60 (μm) was prepared as the holding material 14.

[0084] A gamma-butyrolactone solution containing 35 wt.% of 1,2,3,4-tetramethylimidazolinium phthalate was prepared as an electrolyte. The capacitor element 10 was immersed in the electrolyte in a reduced pressure atmosphere. The base material of the support material 14 was impregnated with a gamma-butyrolactone solution containing an antioxidant, (±)-α-tocopherol, at a concentration of 10 (wt%). The support material 14 used here had the shape shown in FIG. 5(A). The support material 14 and the sealing body 12 through which the lead terminals 112, 113 and the 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 manner, an aluminum electrolytic capacitor 1 was obtained.

[0085] (Example No. 2) The manufacturing method differs from that of Example No. 1 in the following respects: The substrate of the support 14 was impregnated with the above-mentioned electrolyte solution containing (±)-α-tocopherol at a concentration of 10 (wt %).

[0086] (Example No. 3) The manufacturing method differs from that of Example No. 1 in the following respects. Capacitor element 10 was immersed in an electrolyte solution containing (±)-α-tocopherol at a concentration of 10 (wt%). After mounting holding material 14 not impregnated with an antioxidant on capacitor element 10, holding material 14 was impregnated with the electrolyte from separator 103 of capacitor element 10.

[0087] (Example No. 4) The manufacturing method differs from that of Example No. 1 in the following respects: After the substrate of the retention material 14 was immersed in a γ-butyrolactone solution containing 10 (wt%) of (±)-α-tocopherol, the γ-butyrolactone solvent was removed from the retention material 14 by drying treatment.

[0088] (Example No. 5) The manufacturing method differs from that of Example No. 1 in the following respects: The base material of the retaining material 14 was impregnated with a γ-butyrolactone solution containing (±)-α-tocopherol at a concentration of 2.5 (wt %).

[0089] (Example No. 6) The manufacturing method differs from that of Example No. 1 in the following respects: The base material of the retaining material 14 was impregnated with a γ-butyrolactone solution containing (±)-α-tocopherol at a concentration of 20 (wt %).

[0090] (Example No. 7) The manufacturing method differs from that of Example No. 1 in the following respects: The base material of the retention material 14 was impregnated with a γ-butyrolactone solution containing uric acid at a concentration of 10 (wt %).

[0091] (Example No. 8) The manufacturing method differs from that of Example No. 1 in the following respects: The base material of the retaining material 14 was impregnated with a γ-butyrolactone solution containing hydroquinone at a concentration of 10 (wt %).

[0092] (Example No. 9) The manufacturing method differed from that of Example No. 1 in the following respects: The retaining material 14 used had the shape shown in FIG.

[0093] (Example No. 10) The manufacturing method differed from that of Example No. 1 in the following respects: The retaining material 14 was adhered to the surface of the sealing body 12 with polyethylene glycol as an adhesive.

[0094] (Example No. 11) The manufacturing method differs from that of Example No. 1 in the following respects: 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 manufacturing method differs from that of Example No. 1 in the following respects: The same antioxidant as that of the retaining material 14 was impregnated into the separator 103.

[0096] (Example No. 13) The manufacturing method differs from that of Example No. 1 in the following respects. The capacitor element 10 was subjected to a re-chemical conversion treatment in an ammonium phosphate aqueous solution with a voltage of 50 (V) applied to it before being immersed in the electrolyte. After washing and drying the capacitor element 10, the capacitor element 10 was immersed in a conductive polymer PEDOT / PSS (poly(3,4-ethylenedioxythiophene) polystyrene sulfonate) dispersion in an atmosphere reduced to -0.97 (MPa) from atmospheric pressure. A γ-butyrolactone solution containing 35 (wt%) of 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. A conductive polymer hybrid aluminum electrolytic capacitor was thus obtained.

[0097] (Example No. 14) The manufacturing method differs from that of Example No. 13 in the following respects: The substrate of the support 14 was impregnated with the above-mentioned electrolyte solution containing (±)-α-tocopherol at a concentration of 10 (wt %).

[0098] (Example No. 15) The manufacturing method differs from that of Example No. 13 in the following respects. Capacitor element 10 was immersed in an electrolyte solution containing (±)-α-tocopherol at a concentration of 10 (wt%). After mounting holding material 14 not impregnated with an antioxidant on capacitor element 10, holding material 14 was impregnated with the electrolyte from separator 103 of capacitor element 10.

[0099] (Example No. 16) The manufacturing method differs from that of Example No. 13 in the following respects: After the substrate of the retention material 14 was immersed in a γ-butyrolactone solution containing 10 (wt%) of (±)-α-tocopherol, the γ-butyrolactone solvent was removed from the retention material 14 by drying treatment.

[0100] (Example No. 17) The manufacturing method differs from that of Example No. 13 in the following respects: The base material of the retaining material 14 was impregnated with a γ-butyrolactone solution containing (±)-α-tocopherol at a concentration of 2.5 (wt %).

[0101] (Example No. 18) The manufacturing method differs from that of Example No. 13 in the following respects: The base material of the retaining material 14 was impregnated with a γ-butyrolactone solution containing (±)-α-tocopherol at a concentration of 20 (wt %).

[0102] (Example No. 19) The manufacturing method differs from that of Example No. 13 in the following respects: The base material of the retention material 14 was impregnated with a γ-butyrolactone solution containing uric acid at a concentration of 10 (wt %).

[0103] (Example No. 20) The manufacturing method differs from that of Example No. 13 in the following respects: The base material of the retention material 14 was impregnated with a γ-butyrolactone solution containing hydroquinone at a concentration of 10 (wt %).

[0104] (Example No. 21) The manufacturing method differed from that of Example No. 13 in the following respects: The retaining material 14 used had the shape shown in FIG.

[0105] (Example No. 22) The manufacturing method differed from that of Example No. 13 in the following respects: The retaining material 14 was adhered to the surface of the sealing body 12 with polyethylene glycol as an adhesive.

[0106] (Example No. 23) The manufacturing method differed from that of Example No. 13 in the following respects: 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 manufacturing method differs from that of Example No. 13 in the following respects: The same antioxidant as that of the retaining material 14 was impregnated into the separator 103.

[0108] (Comparative Example No. 1) The manufacturing method differs from that of Example No. 1 in the following respects: Holder 14 is not attached to capacitor element 10 .

[0109] (Comparative Example No. 2) The manufacturing method differs from that of Example No. 13 in the following respects: Holder 14 is not attached to capacitor element 10.

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

[0111] (evaluation) A rated voltage (25 (V)) was applied to each of the aluminum electrolytic capacitors 1 of Examples 1 to 24 and the aluminum electrolytic capacitors of Comparative Examples 1 to 3 in an environment of 130 (°C). The capacitance C (μF) was measured 5000 hours and 8000 hours after the start of the voltage application. The initial capacitance of each aluminum electrolytic capacitor 1 before the evaluation test was Co (μF), the amount of change in capacitance 5000 hours and 8000 hours after the start of the voltage application was ΔC (<0) (μF), and the capacitance reduction rate (%) was calculated as ΔC / Co as an evaluation parameter.

[0112] [Table 1]

[0113] Table 1 shows the capacitance reduction rates (%) after 5000 hours and 8000 hours as the evaluation results of each of the aluminum electrolytic capacitors 1 of Examples 1 to 12. In addition, the solution concentration is shown for the aluminum electrolytic capacitors 1 of Examples 1 to 12 that used (±)-α-tocopherol as an antioxidant.

[0114] [Table 2]

[0115] Table 2 shows the capacitance reduction rates (%) after 5000 hours and 8000 hours as the evaluation results of each of the aluminum electrolytic capacitors 1 of Examples 13 to 24. In addition, the solution concentration is shown for the aluminum electrolytic capacitors 1 of Examples 13 to 24 that used (±)-α-tocopherol as an antioxidant.

[0116] [Table 3]

[0117] Table 2 shows the capacitance reduction rates (%) after 5000 hours and 8000 hours as the evaluation results of each of the aluminum electrolytic capacitors 1 of Comparative Examples No. 1 to No. 3.

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

[0119] In addition, when comparing the capacitance reduction rate of the aluminum electrolytic capacitor 1 of Examples No. 1 to No. 12 with the capacitance reduction rate of the aluminum electrolytic capacitor 1 of Examples No. 13 to No. 24, the reduction rate of Examples No. 1 to No. 12 is larger. 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 separator 103 is impregnated with a conductive polymer, oxidation of sealing body 12 is more effectively suppressed.

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

[0121] In addition, even when the substrate of the retaining material 14 was immersed in an electrolyte solution containing an antioxidant as in Examples No. 2 and No. 12, the rate of decrease in capacitance was suppressed more than in Comparative Examples No. 1 to No. 3. In addition, even when the retaining material 14 was impregnated with an antioxidant from the separator 103 as in Examples No. 3 and No. 15, the rate of decrease in capacitance was suppressed more than in Comparative Examples No. 1 to No. 3. In addition, even when the solvent of the antioxidant impregnated in the retaining material 14 was removed from the separator 103 as in Examples No. 4 and No. 16, the rate of decrease in capacitance was suppressed more than in Comparative Examples No. 1 to No. 3.

[0122] In addition, even when an antioxidant other than (±)-α-tocopherol was used as in Examples Nos. 7, 8, 19, and 20, the rate of decrease in capacitance was suppressed more than in Comparative Examples Nos. 1 to 3. In addition, even when the shape of the retaining material 14 was changed as in Examples Nos. 9 and 21, the rate of decrease in capacitance was suppressed more than in Comparative Examples Nos. 1 to 3. In addition, even when the retaining material 14 was attached to the surface of the sealing body 12 with an adhesive as in Examples Nos. 10 and 22, the rate of decrease in capacitance was suppressed more than in Comparative Examples Nos. 1 to 3.

[0123] In addition, even when the retaining material 14 was made of gel, as in Examples 11 and 23, the rate of decrease in capacitance was suppressed more than in Comparative Examples 1 to 3. In addition, even when the separator 103 was impregnated with the same antioxidant as the retaining material 14, as in Examples 12 and 24, the rate of decrease in capacitance was suppressed more than in Comparative Examples 1 to 3.

[0124] Fig. 9 is a diagram showing the change over time in the capacitance reduction rate of Example No. 1 and Comparative Examples No. 1 and No. 3. The horizontal and vertical axes of the graph in Fig. 9 represent time (h) and reduction rate (ΔC / Co) (%), respectively.

[0125] The difference in the reduction rate between Example No. 1 and Comparative Example No. 1 is larger than the difference in the reduction rate between Example No. 1 and Comparative Example No. 3. In the aluminum electrolytic capacitor of Comparative Example No. 3, the separator is impregnated with an antioxidant, so oxidation of the sealing body is suppressed, and the reduction rate is lower than that of Comparative Example No. 1.

[0126] 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 realize a sufficient supply amount, and since the separator is in direct contact with the sealing body, the electrolyte easily flows into the sealing body. Therefore, compared to Example No. 1, it is not possible to effectively suppress oxidation of the sealing body.

[0127] Thus, the aluminum electrolytic capacitor 1, its manufacturing method, and holding material 14 of this embodiment prevent direct contact between the electrolyte contained in separator 103 in capacitor element 10 and sealing body 12, and also prevent oxidation by supplying an antioxidant to the surface of sealing body 12. As a result, deterioration of the characteristics of aluminum electrolytic capacitor 1 can be prevented.

[0128] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention 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 terminal 140 Insertion hole 141,143,144 Cutting 142 Notch

Claims

1. a capacitor element in which an anode foil and a cathode foil are wound with a separator therebetween; a case for housing the capacitor element; a sealing body that seals an opening of the case; and a support material disposed between the capacitor element and the sealing body, the support material supporting an antioxidant that is more easily oxidized than the sealing body.

2. 2. The electrolytic capacitor according to claim 1, wherein the support material is a sheet-like member covering at least a portion of a surface of the sealing body.

3. a pair of lead terminals extending from the anode foil and the cathode foil, respectively, are provided on a lower portion of the capacitor element; the sealing body has a pair of insertion holes through which the pair of lead terminals are respectively inserted, 3. The electrolytic capacitor according to claim 1, wherein the holding member has a pair of insertion holes into which the pair of lead terminals are respectively inserted.

4. 4. The electrolytic capacitor according to claim 3, wherein the holding material has a notch extending from at least one of the pair of insertion holes to an edge of the holding material.

5. 4. The electrolytic capacitor according to claim 3, wherein the diameter of the pair of insertion holes is 0.5 to 2 times the diameter of the pair of lead terminals.

6. a pair of lead terminals extending from the anode foil and the cathode foil, respectively, are provided on a lower portion of the capacitor element; the sealing body has a pair of insertion holes through which the pair of lead terminals are respectively inserted, 3. The electrolytic capacitor according to claim 1, wherein the holding member has a pair of notches through which the pair of lead terminals pass, respectively.

7. 7. The electrolytic capacitor according to claim 6, wherein at least one of the pair of notches extends to an edge of the support material.

8. a pair of lead terminals extending from the anode foil and the cathode foil, respectively, are provided on a lower portion of the capacitor element; the sealing body has a pair of insertion holes through which the pair of lead terminals are respectively inserted, 3. The electrolytic capacitor according to claim 1, wherein the holding member has a pair of notches that fit respectively with the pair of lead terminals.

9. 3. The electrolytic capacitor according to claim 1, wherein the separator extends toward the support material beyond the anode foil and the cathode foil and is pressed against the support material.

10. 3. The electrolytic capacitor according to claim 1, wherein the antioxidant includes at least one of a photoantioxidant, a vitamin antioxidant, an amine-based antioxidant, a phenol-based antioxidant, a phosphorus-based antioxidant, and a sugar-based antioxidant.

11. 3. The electrolytic capacitor according to claim 1, wherein the support material is a gel medium or a base material made of organic fibers, inorganic fibers, or resin fibers.

12. 3. The electrolytic capacitor according to claim 1, wherein the support is adhered to the sealing member by an adhesive that swells with the electrolyte impregnated in the separator.

13. 3. The electrolytic capacitor according to claim 1, wherein the retaining material retains a solution containing 2.5 (wt %) to 20 (wt %) of α-tocopherol as the antioxidant.

14. 3. The electrolytic capacitor according to claim 1, wherein the capacitor element has a conductive polymer layer formed thereon.

15. a step of attaching a seal to a capacitor element in which an anode foil and a cathode foil are wound with a separator interposed therebetween, the seal being attached via a retaining material that retains an antioxidant that is easily oxidized by the seal; and housing the capacitor element in a case and sealing an opening of the case with the sealing body.

16. 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 case with the sealing body, The pair of lead terminals are inserted into the pair of insertion holes of the holding material, respectively; 16. The method for manufacturing an electrolytic capacitor according to claim 15, wherein the pair of lead terminals inserted into the pair of insertion holes are inserted into a pair of through holes in the sealing body, respectively.

17. 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 case with the sealing body, The pair of lead terminals are passed through a pair of notches of the holding material, respectively; 16. The method for manufacturing an electrolytic capacitor according to claim 15, wherein the pair of lead terminals passed through the pair of cutouts are inserted into a pair of insertion holes in the sealing body, respectively.

18. 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 case with the sealing body, The pair of lead terminals are fitted into the pair of notches of the holding material, respectively; 16. The method for manufacturing an electrolytic capacitor according to claim 15, wherein the pair of lead terminals fitted in the pair of notches are inserted into a pair of insertion holes of the sealing body, respectively.

19. The present invention is provided in an electrolytic capacitor having a capacitor element in which an anode foil and a cathode foil are wound with a separator interposed therebetween, a case for accommodating the capacitor element, and a sealing body for sealing an opening of the case, A retaining material disposed between the capacitor element and the sealing body, the retaining material retaining an antioxidant that is more easily oxidized than the sealing body.

20. The retention material according to claim 19, characterized in that the antioxidant includes at least one of a photoantioxidant, a vitamin antioxidant, an amine-based antioxidant, a phenol-based antioxidant, a phosphorus-based antioxidant, and a sugar-based antioxidant.

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

22. The retention material according to claim 19 or 20, characterized in that the retention material retains a solution containing 2.5 (wt %) to 20 (wt %) of α-tocopherol as the antioxidant.

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