Electrolytic capacitor and method for manufacturing the same, and electrolytic capacitor module

Abstract

The electrolytic capacitor of the present invention comprises a capacitor element and a liquid component. The capacitor element comprises an anode body having a dielectric layer on the surface and a conductive polymer covering a portion of the dielectric layer. The liquid component comprises a first solvent and a polyalkylene glycol component. The first solvent comprises at least a glycerol component.

Description

Technical Field

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

[0002] As a small, large-capacity, and low-ESR (equivalent series resistance) capacitor, an electrolytic capacitor having an anode body formed with a dielectric layer, a conductive polymer covering at least a portion of the dielectric layer, and an electrolyte is considered promising. As the electrolyte, a liquid component such as a non-aqueous solvent or a solution obtained by dissolving a solute in a non-aqueous solvent is used.

[0003] Patent document 1 proposes the following electrolytic capacitor, which includes a capacitor element, a conductive polymer and an electrolyte, wherein the capacitor element includes an anode body formed with a dielectric layer, the conductive polymer covers at least a portion of the surface of the dielectric layer, and the electrolyte contains a non-aqueous solvent, a glycerol compound and an ionic solute, and the mass of the glycerol compound contained in the electrolyte is in the range of 2 to 100 times the mass of the conductive polymer attached to the capacitor element.

[0004] Patent document 2 proposes the manufacture of a solid electrolytic capacitor having a first introduction step and a second introduction step, wherein the first introduction step is a step of introducing a dispersion containing a microparticle-shaped conductive polymer compound and a first water-soluble compound into a capacitor element, and the second introduction step is a step of introducing a water-soluble polymer solution containing liquid polyethylene glycol, water and a second water-soluble compound in a manner surrounding the solid electrolyte layer formed by the first introduction step, and in the second introduction step, a water-soluble polymer solution that does not contain a microparticle-shaped conductive polymer compound is used, and the same substance as the first water-soluble compound is used as the second water-soluble compound. Here, the first water-soluble compound is a compound having a molecular weight of 100 or more and less than 200 and having 4 or more hydroxyl groups, diglycerol, or both thereof.

[0005] Patent Document 3 proposes using an electrolyte solution containing a polyglycerol derivative in a solid electrolytic capacitor.

[0006] Patent Document 4 proposes using an electrolyte solution containing an alkylene oxide adduct of a tri- to octa-valent polyol in a hybrid electrolytic capacitor.

[0007] Patent Document 5 proposes a solid electrolytic capacitor in which voids in a capacitor element are filled with a solvent containing polyoxyethylene glycerol or a derivative thereof.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application Publication No. 2019-71469

[0011] Patent Document 2: Japanese Patent No. 6535409

[0012] Patent Document 3: Japanese Patent Application Publication No. 2018-110232

[0013] Patent Document 4: Japanese Patent Application Publication No. 2017-69549

[0014] Patent Document 5: Japanese Patent Application Publication No. 2016-72284 Summary of the invention

[0015] Problems to be solved by the invention

[0016] Electrolytic capacitors are sometimes used in high-temperature environments depending on their applications, and therefore require high heat resistance.

[0017] Means for solving problems

[0018] A first aspect of the present invention relates to an electrolytic capacitor comprising a capacitor element and a liquid component, wherein the capacitor element comprises an anode body having a dielectric layer on its surface and a conductive polymer covering a portion of the dielectric layer, and the liquid component comprises a first solvent and a polyalkylene glycol component, wherein the first solvent comprises at least a glycerol component.

[0019] A second aspect of the present invention relates to an electrolytic capacitor comprising a capacitor element and a liquid component, wherein the capacitor element comprises an anode body having a dielectric layer on its surface, a cathode body, and a conductive polymer disposed between the anode body and the cathode body, wherein the liquid component comprises a first solvent and a polyalkylene glycol component, wherein the solubility parameter of the first solvent is 15 (cal / cm 3 ) 1 / 2 above.

[0020] A third aspect of the present invention relates to an electrolytic capacitor module including a plurality of the above-described electrolytic capacitors connected in parallel.

[0021] A fourth aspect of the present invention relates to a method for manufacturing an electrolytic capacitor, which is a method for manufacturing an electrolytic capacitor including a capacitor element and a liquid component, wherein the capacitor element includes an anode body having a dielectric layer on its surface and a conductive polymer covering a portion of the dielectric layer, the manufacturing method comprising: a step of preparing a liquid component including a first solvent including at least a glycerol component and a polyalkylene glycol component, a conductive polymer impregnation step of impregnating the dielectric layer with the conductive polymer, and a liquid component impregnation step of impregnating the capacitor element with the liquid component after the conductive polymer impregnation step.

[0022] A fifth aspect of the present invention relates to a method for manufacturing an electrolytic capacitor, which is a method for manufacturing an electrolytic capacitor comprising a capacitor element and a liquid component, wherein the capacitor element comprises an anode body having a dielectric layer on its surface and a conductive polymer covering a portion of the dielectric layer, the manufacturing method comprising: preparing a conductive polymer having a solubility parameter of 15 (cal / cm 3 ) 1 / 2 The above-mentioned liquid component preparation step of the first solvent and the polyalkylene glycol component, the conductive polymer impregnation step of impregnating the dielectric layer with the conductive polymer, and the liquid component impregnation step of impregnating the capacitor element with the liquid component after the conductive polymer impregnation step.

[0023] Effects of the Invention

[0024] An electrolytic capacitor and an electrolytic capacitor module having excellent heat resistance can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic cross-sectional view of an electrolytic capacitor according to one embodiment of the present invention.

[0026] Figure 2 Yes Figure 1 A schematic diagram of a portion of the capacitor element of an electrolytic capacitor expanded. DETAILED DESCRIPTION

[0027] When an electrolytic capacitor having a liquid component containing a non-aqueous solvent is used under a high temperature environment, the non-aqueous solvent is easy to evaporate and it is difficult to obtain sufficient durability. Therefore, it is preferred to use a liquid component containing a non-aqueous solvent with a higher boiling point. However, when the boiling point of the non-aqueous solvent is high, the viscosity of the liquid component becomes high, and it is difficult to infiltrate the capacitor element. In addition, if this non-aqueous solvent is used, the dissociation of the solute is reduced, and it is difficult to ensure the characteristics of the electrolytic capacitor. In addition, if the connection of carbon atoms in the molecular chain of the non-aqueous solvent increases, the affinity with the elastic polymer contained in the sealing body becomes high, and the sealing body is easy to swell due to the non-aqueous solvent. If the electrolytic capacitor with a swollen sealing body due to the non-aqueous solvent is exposed to a high temperature environment, the deterioration of the sealing body is aggravated and the durability is reduced. In the past, various non-aqueous solvents can be cited as non-aqueous solvents used in the liquid component of the electrolytic capacitor, but it is very difficult to obtain a liquid component with excellent balance of characteristics as described above.

[0028] An electrolytic capacitor according to one aspect of the present invention includes a capacitor element including a conductive polymer, wherein a liquid component including a first solvent and a polyalkylene glycol component is used in the electrolytic capacitor. Here, the first solvent satisfies any one of the following conditions (a) and (b).

[0029] (a) The first solvent contains at least a glycerin component.

[0030] (b) The solubility parameter (SP value) of the first solvent is 15 (cal / cm 3 ) 1 / 2 above.

[0031] Although this first solvent tends to show a high hydrophilicity, it has a low solubility in non-aqueous solvents and is difficult to be used as a liquid component of an electrolytic capacitor in practice. However, by combining this first solvent with a polyalkylene glycol component, the dissolution of the first solvent becomes easy, and the viscosity of the liquid component can be suppressed to a relatively low level, which can ensure the high dissociation of the solute, thereby being able to be used as a liquid component of an electrolytic capacitor. In addition, by making this liquid component contain the first solvent, it is difficult to volatilize even in a high temperature environment, and the first solvent has a low affinity for the elastic polymer contained in the sealing body, so it is difficult for the liquid component to swell the sealing body. Therefore, the high heat resistance of the electrolytic capacitor can be ensured. In addition, the glycerol component tends to improve the orientation of the conductive polymer contained in the capacitor element, thereby improving the conductivity of the conductive polymer.

[0032] Hereinafter, the structure of the electrolytic capacitor and the method for manufacturing the electrolytic capacitor will be described in more detail.

[0033] [Electrolytic capacitors]

[0034] An electrolytic capacitor includes a capacitor element and a liquid component. An electrolytic capacitor generally includes a container for accommodating the capacitor element and the liquid component and a sealing body for sealing the container.

[0035] (Liquid ingredients)

[0036] The liquid component may contain one type of the first solvent, or may contain two or more types of the first solvent.

[0037] (First solvent)

[0038] In the above condition (a), the first solvent contains at least a glycerol component. The first solvent may contain, in addition to the glycerol component, a solvent having an SP value of 15 (cal / cm 3 ) 1 / 2 From the viewpoint of easily ensuring the effect of the glycerol component, the ratio of the glycerol component in the first solvent may be 90% by mass or more. The first solvent may also be composed of only the glycerol component.

[0039] Generally, when a component having many hydroxyl groups is used in the liquid component, it is easy to penetrate the sealing body. However, by using a glycerol component, a large amount of glycerol component remains in the liquid component even in a high temperature environment, so that the high orientation of the conductive polymer can be maintained.

[0040] Examples of the glycerin component include glycerin or a derivative thereof, polyglycerin or a derivative thereof, etc. The liquid component may contain one type of glycerin component, or may contain two or more types of glycerin components.

[0041] Polyglycerol contains a repeating structure of glycerol units. The number of repeating glycerol units contained in polyglycerol is, for example, 2 to 20, 2 to 12 or 2 to less than 12, 2 to 10 or 2 to 6. As polyglycerol, diglycerol, triglycerol, etc. are also preferred.

[0042] As derivatives of glycerol or polyglycerol, for example, esters in which at least a part of the hydroxyl groups of glycerol or polyglycerol are esterified, alkylene oxide adducts of glycerol or polyglycerol, etc. can be mentioned. As esters, for example, organic acid esters (acetic acid esters, etc.) can be mentioned. As alkylene oxide adducts, more specifically, adducts obtained by adding one molecule of alkylene oxide to at least a part of the hydroxyl groups relative to one hydroxyl group can be mentioned. As alkylene oxides, for example, C 2-4 Alkylene oxide, preferably C 2-3 Alkylene oxide or ethylene oxide. When the alkylene oxide adduct contains a plurality of alkylene oxide units, at least two alkylene oxide units may be of the same type, or all alkylene oxide units may be of different types.

[0043] The number of hydroxyl groups in the derivative is not particularly limited. The derivative may not have a hydroxyl group. The number of hydroxyl groups in the derivative may be, for example, 0 to 10, 0 to 8, 1 to 8, or 2 to 8.

[0044] From the viewpoint of facilitating the orientation of the conductive polymer, it is preferred to use a glycerol component having a hydroxyl group on at least two adjacent carbon atoms. As a derivative, an alkylene oxide adduct is preferred. These glycerol components are easy to swell the conductive polymer and are easy to orient the conductive polymer. Therefore, the film repair effect of the dielectric layer is improved and the ESR can be reduced.

[0045] In the above condition (b), the SP value is 15 (cal / cm 3 ) 1 / 2 Specific examples of the first solvent include the glycerol component. Among the glycerol components, glycerol or its alkylene oxide adduct, polyglycerol or its alkylene oxide adduct having a glycerol unit repeating number of 2 or more and 12 or less (2 or more and 10 or less, etc.) are preferred. The first solvent may include a SP value of 15 (cal / cm 3 ) 1 / 2 The above solvents may contain two or more. The SP value is, for example, 22 (cal / cm 3 ) 1 / 2Below, it can also be 20 (cal / cm 3 ) 1 / 2 It should be noted that the SP value is 15 (cal / cm 3 ) 1 / 2 The first solvent is preferably an organic solvent. 3 ) 1 / 2 ≈2.05(J / cm 3 ) 1 / 2 ≈2.05(MPa) 1 / 2 .

[0046] The content of the first solvent in the liquid component is, for example, 5% by mass or more, preferably 10% by mass or more, more preferably greater than 10% by mass, and may be 15% by mass or more, 20% by mass or more, 25% by mass or more, or 30% by mass or more. When the content of the first solvent is in this range, it is easy to swell the conductive polymer. In addition, by making the ratio of other components relatively low, the effect of suppressing the swelling of the sealing body caused by the liquid component is improved. The content of the first solvent in the liquid component may be 95% by mass or less, preferably 90% by mass or less, more preferably 75% by mass or less or 70% by mass or less. When the content of the first solvent is in this range, the viscosity of the liquid component may be controlled to be relatively low, and it is easy to ensure the high dissociation of the solute. These lower limits and upper limits may be combined arbitrarily.

[0047] (Polyalkylene glycol component)

[0048] The polyalkylene glycol component may be any one having a repeating structure of alkylene oxide. Examples of alkylene oxide include C 2-4 Alkylene oxide, also C 2-3 Alkylene oxide. Specific examples of alkylene oxide include ethylene oxide, propylene oxide, oxetane, butylene oxide, etc. The polyalkylene glycol component may contain one alkylene oxide unit or two or more alkylene oxide units. The polyalkylene glycol component containing two or more alkylene oxide units may contain, for example, ethylene oxide units and C 3-4 Alkylene oxide unit: When a polyalkylene glycol component containing two or more alkylene oxide units is used, the effect of reducing the viscosity of the liquid component is enhanced.

[0049] As the polyalkylene glycol component, for example, polyalkylene glycol, a copolymer comprising two or more alkylene oxide units and a polyalkylene oxide adduct of a polyol can be cited. As a polyol, glycerol, trimethylolpropane and sugar alcohol can be cited. As a sugar alcohol, sugar alcohols (monosaccharide alcohols, disaccharide alcohols, etc.) with more than 4 hydroxyls can be cited. As a sugar alcohol, for example, sorbitol, mannitol, erythritol, pentaerythritol, threitol, arabitol, ribitol, xylitol, galactitol, rhamnitol, isomalt, maltitol, lactitol, palatinose and their reduced bodies (such as reduced palatinose) can be cited. In the polyalkylene oxide adduct, more than two polyalkylene oxide chains can be the same polyalkylene oxide chains, or all polyalkylene oxide chains can be different.

[0050] The liquid component may contain one type of polyalkylene glycol component, or may contain two or more types of polyalkylene glycol components.

[0051] The weight average molecular weight (Mw) of the polyalkylene glycol component is, for example, more than 150, preferably more than 200. When Mw is such a range, it is easy to dissolve the first solvent, and although the liquid component contains the first solvent, the viscosity of the liquid component can be controlled to be relatively low. In addition, the effect of suppressing the volatilization of the liquid component can be improved. Mw is, for example, less than 3000, and may be less than 2000 or less than 1000, or may be less than 800 or less than 600. When Mw is such a range, the viscosity of the liquid component can be controlled to a further low value. These lower limits and upper limits can be arbitrarily combined.

[0052] In this specification, the weight average molecular weight (Mw) is a value in terms of polystyrene measured by gel permeation chromatography (GPC). In general, GPC is measured using a polystyrene gel column and water / methanol (volume ratio 8 / 2) as a mobile phase.

[0053] The content of the polyalkylene glycol component in the liquid component is, for example, 5% by mass or more, and may be 10% by mass or more, 25% by mass or more, 30% by mass or more, or 50% by mass or more. In this case, the solubility of the first solvent can be improved, and despite the first solvent, the viscosity of the liquid component can be controlled to be lower. The content of the polyalkylene glycol component in the liquid component is, for example, 95% by mass or less, and may be 90% by mass or less, less than 90% by mass, less than 80% by mass, less than 75% by mass, less than 70% by mass, or less than 50% by mass. In this case, even if an electrolytic capacitor is used under a high temperature environment, the swelling of the sealing body caused by the liquid component can be more effectively suppressed. These lower limits and upper limits can be combined arbitrarily.

[0054] The content of the polyalkylene glycol component in the liquid component is preferably greater than the content of the first solvent. This makes it easier to dissolve the first solvent and to ensure high dissociation of the solute in the liquid component, thereby improving the film repair effect of the dielectric layer.

[0055] (Non-aqueous solvent)

[0056] The liquid component may contain a non-aqueous solvent other than the first solvent and the polyalkylene glycol component. Examples of the non-aqueous solvent include sulfone compounds, lactone compounds, carbonate compounds, glycerol components, and polyols other than the polyalkylene glycol component.

[0057] As sulfone compounds, sulfolane, dimethyl sulfoxide and diethyl sulfoxide can be mentioned. As lactone compounds, γ-butyrolactone and γ-valerolactone can be mentioned. As carbonate compounds, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, ethylene carbonate, propylene carbonate and fluoroethylene carbonate can be mentioned.

[0058] Examples of the polyol include alkylene glycol (ethylene glycol, propylene glycol, etc.), trimethylolpropane, sugar alcohols having four or more hydroxyl groups or derivatives thereof. As sugar alcohols, reference may be made to the sugar alcohols described as polyols constituting the polyalkylene glycol component. As derivatives of sugar alcohols, reference may be made to the examples of derivatives of glycerol.

[0059] The liquid component may contain one type of these non-aqueous solvents, or may contain two or more types.

[0060] From the viewpoint of easily obtaining the effects brought about by the first solvent and the polyalkylene glycol component and improving the effect of suppressing swelling of the sealing body caused by the liquid component, the content of such non-aqueous solvent in the liquid component is preferably 10% by mass or less, more preferably 5% by mass or less or 1% by mass or less.

[0061] (Solute)

[0062] The liquid component may contain a solute. Examples of the solute include an acid component, an alkaline component, and the like. The liquid component preferably contains at least an acid component. When the conductive polymer component contains a dopant, the acid component in the electrolyte suppresses the dedoping phenomenon of the dopant, thereby stabilizing the conductivity of each polymer component. In addition, even when the dopant is dedoped from the conductive polymer component, it is easy to maintain a low ESR because the acid component of the electrolyte is re-doped at the point of the dedoping trace. The electrolyte may also contain an alkaline component while containing an acid component. At least a portion of the acid component is neutralized by the alkaline component. Thus, the corrosion of the electrode caused by the acid component can be suppressed while increasing the concentration of the acid component.

[0063] Examples of the acid component include carboxylic acids, sulfur-containing acids (sulfuric acid, sulfonic acid, etc.), boron-containing acids (boric acid, halogenated boric acid (tetrafluoroboric acid, etc.), or partial esters thereof), phosphorus-containing acids (phosphoric acid, halogenated phosphoric acid (hexafluorophosphoric acid, etc.), phosphonic acid, phosphinic acid, or partial esters thereof), nitric acid, and nitrous acid. Condensates of carboxylic acids and inorganic acids (boric acid, phosphoric acid, etc.) may also be used as the acid component. The liquid component may contain one acid component, or may contain two or more acid components.

[0064] As the acid component, carboxylic acid, sulfonic acid, condensate of carboxylic acid and inorganic acid, etc. are preferred. As sulfonic acid, for example, aliphatic sulfonic acid with carbon number 1 to 30 and aromatic sulfonic acid with carbon number 6 to 30 can be mentioned. As carboxylic acid, aliphatic carboxylic acid, aromatic carboxylic acid, etc. can be mentioned. Among them, aromatic carboxylic acid is relatively stable. In addition, polycarboxylic acid (polycarboxylic acid) having two or more hydroxyl groups is also preferred. Specifically, phthalic acid, pyromellitic acid, etc. can be used as aromatic carboxylic acid. Among them, phthalic acid is preferred.

[0065] As the condensate of carboxylic acid and inorganic acid, a condensate of carboxylic acid and boric acid is preferred. As such a condensate, specifically, borodisalicylic acid, borodiglycolic acid, borodioxalic acid, etc. can be used.

[0066] Examples of the alkaline component include ammonia, amines (specifically, primary amines, secondary amines, and tertiary amines), quaternary ammonium salt compounds, and amidinium compounds. The liquid component may contain one alkaline component or two or more alkaline components.

[0067] Amines may be any of aliphatic, aromatic and heterocyclic. As amines, for example, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, N,N-diisopropylethylamine, tetramethylethylenediamine, hexamethylenediamine, spermidine, spermine, adamantane, aniline, phenethylamine, toluidine, pyrrolidine, piperidine, piperazine, morpholine, imidazole, pyridine, pyridazine, pyrimidine, pyrazine, 4-dimethylaminopyridine, etc. may be mentioned. As quaternary ammonium salt compounds, for example, amidine compounds (including imidazole compounds) may be mentioned.

[0068] The acid component and the base component may be contained in the liquid component in a free state or in the form of a salt. The liquid component may contain an organic salt. As the organic salt, an organic salt in which at least one of the acid component and the base component is organic may be cited. As the organic salt, for example, trimethylamine maleate, triethylamine phthalate, ethyldimethylamine phthalate, mono-1,2,3,4-tetramethylimidazolinium phthalate, mono-1,3-dimethyl-2-ethylimidazolinium phthalate, triethylamine boronate disalicylate may be used.

[0069] The pH of the liquid component is preferably 4 or less, and may be 3.8 or less, or 3.6 or less. By setting the pH of the electrolyte solution to such a range, it is easy to suppress the deterioration of the conductive polymer component. The pH is preferably 1.0 or more.

[0070] The concentration of the solute in the liquid component is, for example, 0.1 mass % or more, preferably 0.5 mass % or more. When the concentration of the solute is in this range, by combining with the first solvent and the polyalkylene glycol component, the solute can be dissociated with high dissociation in the liquid component, and the high film repairability of the dielectric layer can be ensured. The concentration of the solute is preferably 25 mass % or less, more preferably 20 mass % or less or 15 mass % or less. When the concentration of the solute is in this range, dedoping of the dopant can be suppressed. These lower limits and upper limits can be combined arbitrarily.

[0071] (other)

[0072] The water content in the liquid component can be less than 1.5 mass % or less than 1 mass %, preferably less than 0.5 mass %, and can also be less than 0.1 mass % or less than 0.01 mass %. The first solvent has a tendency to have a relatively low solubility relative to water, but by combining with the polyalkylene glycol component, even if the water content in the liquid component is small, the first solvent can be easily dissolved in the polyalkylene glycol component by heating. In addition, although the first solvent has high crystallinity, once it is dissolved in the polyalkylene glycol component, precipitation is suppressed. It should be noted that the water content is the content in the liquid component of the electrolytic capacitor in the initial state.

[0073] The liquid component containing the first solvent tends to have a higher viscosity at 20°C, but by combining with the polyalkylene glycol component, the first solvent can be dissolved in the polyalkylene glycol component by heating. The viscosity of the liquid component at 20°C is, for example, 200 mPa·s or more, or 500 mPa·s or more. Even if the viscosity of the liquid component at 20°C is in this range, the viscosity can be reduced by heating. Therefore, the liquid component can be easily infiltrated into the conductive polymer of the capacitor element, making it easy to ensure high film repairability of the dielectric layer, and it is easy to orient the conductive polymer to ensure high conductivity.

[0074] In this specification, the viscosity of the liquid component can be measured using a vibration viscometer. As a vibration viscometer, for example, a vibration viscometer VM-100A manufactured by CBC Corporation can be used.

[0075] (Capacitor Components)

[0076] The capacitor element includes at least an anode body having a dielectric layer on its surface and a conductive polymer covering a portion of the dielectric layer.

[0077] (Anode)

[0078] The anode body may include a valve metal, an alloy including a valve metal, a compound including a valve metal, and the like. These materials may be used alone or in combination of two or more. For example, aluminum, tantalum, niobium, and titanium are preferably used as valve metals. An anode body having a porous surface may be obtained, for example, by roughening the surface of a substrate (foil-shaped or plate-shaped substrate, etc.) containing a valve metal by etching or the like. In addition, the anode body may also be a formed body of particles containing a valve metal or a sintered body thereof. It should be noted that the sintered body has a porous structure.

[0079] (Dielectric layer)

[0080] The dielectric layer is formed by anodizing the valve metal on the surface of the anode body by chemical conversion treatment or the like. The dielectric layer can be formed in a manner that covers at least a portion of the anode body. The dielectric layer is usually formed on the surface of the anode body. Since the dielectric layer is formed on the porous surface of the anode body, it is formed along the inner wall surface of the pores and depressions (pits) on the surface of the anode body.

[0081] The dielectric layer includes an oxide of a valve metal. For example, when tantalum is used as the valve metal, the dielectric layer includes Ta2O5, and when aluminum is used as the valve metal, the dielectric layer includes Al2O3. It should be noted that the dielectric layer is not limited thereto, as long as it is a material that functions as a dielectric. When the surface of the anode body is porous, the dielectric layer is formed along the surface of the anode body (including the inner wall surface of the hole).

[0082] (Conductive polymer layer)

[0083] The conductive polymer is attached so as to cover a part of the dielectric layer to form a conductive polymer layer. The conductive polymer forms at least a part of the cathode body of the electrolytic capacitor. The conductive polymer layer may further contain at least one of a dopant and an additive as required.

[0084] The conductive polymer includes polypyrrole, polythiophene, polyfuran, polyaniline, polyacetylene, polyphenylene, polyphenylene vinylene, polyacene, polythiophene vinylene, etc. These may be used alone or in combination of two or more, or may be a copolymer of two or more monomers.

[0085] It should be noted that in this specification, polypyrrole, polythiophene, polyfuran, polyaniline, etc. refer to polymers with polypyrrole, polythiophene, polyfuran, polyaniline, etc. as basic skeletons, respectively. Therefore, polypyrrole, polythiophene, polyfuran, polyaniline, etc. may also include their respective derivatives. For example, polythiophene includes poly(3,4-ethylenedioxythiophene) and the like.

[0086] The dopant may be a polyanion. Specific examples of the polyanion include polyvinyl sulfonic acid, polystyrene sulfonic acid, polyallyl sulfonic acid, polyacryl sulfonic acid, polymethacryl sulfonic acid, poly(2-acrylamide-2-methylpropane sulfonic acid), polyisoprene sulfonic acid, polyacrylic acid, etc. They may be used alone or in combination of two or more. In addition, they may be a polymer of a single monomer or a copolymer of two or more monomers. Among them, the polyanion from polystyrene sulfonic acid is preferred.

[0087] The conductive polymer layer can be formed, for example, by chemically polymerizing and / or electrolytically polymerizing raw material monomers on the dielectric layer. Alternatively, it can be formed by contacting a solution in which the conductive polymer is dissolved or a dispersion in which the conductive polymer is dispersed with the dielectric layer. The conductive polymer layer can be formed in a manner that covers at least a portion of the dielectric layer.

[0088] For the cathode body, a metal foil can also be used in the same manner as the anode body. The type of metal is not particularly limited, but valve metals such as aluminum, tantalum, and niobium or alloys containing valve metals are preferably used. The surface of the metal foil can also be roughened as needed. On the surface of the metal foil, a chemically generated coating film can be provided, and a coating of a metal (heterogeneous metal) or a non-metallic film different from the metal constituting the metal foil can also be provided. Examples of heterogeneous metals and non-metals include metals such as titanium and non-metals such as carbon.

[0089] (Spacer)

[0090] When a metal foil is used for the cathode body, a separator may be arranged between the metal foil and the anode body. The separator is not particularly limited, and for example, nonwoven fabrics containing fibers of cellulose, polyethylene terephthalate, vinylon, polyamide (for example, aliphatic polyamide, aromatic polyamide such as aramid) may be used.

[0091] (other)

[0092] The electrolytic capacitor may be of a wound type, a sheet type, or a laminated type. The configuration of the capacitor element may be selected according to the type of the electrolytic capacitor.

[0093] (container)

[0094] As the material of the container, for example, metals such as aluminum, stainless steel, copper, iron, brass, or alloys thereof can be used. The shape of the container is not particularly limited as long as it can accommodate the capacitor element and the liquid component.

[0095] (Sealing body)

[0096] The sealing body is not particularly limited as long as it can seal the opening of the container. The sealing body usually contains an elastic polymer. The sealing body may further contain a cross-linking agent for cross-linking the elastic polymer, an additive, and the like.

[0097] Insulating materials can be used as elastic polymers. Examples of elastic polymers include butyl rubber, isoprene rubber, silicone rubber, fluororubber, ethylene-propylene rubber, chlorosulfonated polyethylene rubber (Hypalon (trademark) rubber, etc.). The sealing body can contain one elastic polymer or two or more.

[0098] Although the elastic polymer has high sealing properties, its heat resistance is insufficient. It will undergo oxidation degradation and become brittle in a high temperature environment, and the sealing function of the sealing body will be reduced. Electrolytic capacitors are sometimes conceived to be used in high temperature environments such as in or near the engine room of a vehicle (car, etc.). For electrolytic capacitors containing liquid components, if the liquid component has a high affinity for the elastic polymer, the elastic polymer is easily swelled by the liquid component. The elastic polymer swollen by the liquid component is more likely to degrade in a high temperature environment. According to the present invention, by using the above-mentioned liquid component, the degradation of the elastic polymer contained in the sealing body can be effectively suppressed, and an electrolytic capacitor with excellent heat resistance can be obtained.

[0099] The proportion of the elastic polymer in the sealing body is, for example, more than 10% by mass, and can also be more than 20% by mass. When the proportion of the elastic polymer is in this range, the sealing body is prone to deterioration under high temperature environment. Even in this case, by using the above-mentioned liquid component, the deterioration of the elastic polymer can be suppressed, and the high heat resistance of the electrolytic capacitor can be ensured. From the viewpoint of being easy to ensure the strength of the sealing body, the proportion of the elastic polymer is preferably less than 50% by mass or less than 40% by mass. It should be noted that, when the elastic polymer is cross-linked by a cross-linking agent, the proportion of the elastic polymer is the proportion of the elastic polymer containing the cross-linking agent.

[0100] The elastic polymer forming the sealing body is usually cross-linked by a cross-linking agent. In particular, an electrolytic capacitor having a sealing body comprising an elastic polymer cross-linked by at least one cross-linking agent selected from a phenolic resin (alkylphenolic resin oligomer, etc.) and a peroxide (organic peroxide, etc.) is suitable for applications requiring particularly high heat resistance. Even when such a sealing body is used, if a conventional liquid component is used, there are cases where the deterioration of the sealing body cannot be suppressed due to the swelling of the liquid component in a high temperature environment. According to the present invention, since the above-mentioned liquid component is used, even when such a sealing body that is intended to be used in a high temperature environment is used, the deterioration of the sealing body can be suppressed, and high heat resistance can be ensured.

[0101] The additives may include, for example, at least one selected from reinforcing agents (carbon such as carbon black), antioxidants, anti-aging agents, crosslinking agents, crosslinking accelerators, dispersing aids, modifiers, vulcanizing agents, vulcanizing aids, and processing aids.

[0102] Electrolytic capacitors have high heat resistance and can be used in high temperature environments. For example, electrolytic capacitors can be used for more than 2,000 hours at a temperature of 120°C (or 150°C). In addition, electrolytic capacitors are also suitable for use in the engine room or its vicinity of vehicles that require high durability and heat resistance.

[0103] The present invention also includes an electrolytic capacitor module having a plurality of electrolytic capacitors as described above. The electrolytic capacitor module may include a plurality of electrolytic capacitors connected in parallel. If a current of more than 20A flows through the entire module of the electrolytic capacitor module obtained by connecting a plurality of conventional electrolytic capacitors in parallel, the temperature of the electrolytic capacitor reaches a high temperature of more than 100°C (sometimes more than 120°C or more than 150°C) due to the ESR of each electrolytic capacitor, and thus the electrolytic capacitor cannot be used. Depending on the circumstances, there are also cases where a large current of more than 50A or more than 100A flows through the entire module. Since the electrolytic capacitor of the present invention has excellent heat resistance, even if a plurality of electrolytic capacitors are connected in parallel to form an electrolytic capacitor module and a current of more than 20A (or more than 50A or more than 100A) flows through the entire module, it can be guaranteed to be used for a long time (specifically more than 1000 hours, preferably more than 1500 hours, and more preferably more than 2000 hours). The allowable current of the entire electrolytic capacitor module may be 20 A or more, 50 A or more, or 100 A or more.

[0104] Figure 1 is a schematic cross-sectional view of an electrolytic capacitor according to this embodiment, Figure 2 This is a schematic diagram showing a portion of a capacitor element of the same electrolytic capacitor expanded.

[0105] The electrolytic capacitor includes, for example, a capacitor element 10, a bottomed case 101 that accommodates the capacitor element 10 and a liquid component (not shown), a sealing body 102 that blocks an opening of the bottomed case 101, a seat plate 103 that covers the sealing body 102, leads 104A and 104B that are led out of the sealing body 102 and penetrate the seat plate 103, and lead tabs 105A and 105B that connect the leads to electrodes of the capacitor element 10. The vicinity of the opening end of the bottomed case 101 is necked inward, and the opening end is crimped in a manner such that it is riveted to the sealing body 102.

[0106] The capacitor element 10 is, for example, Figure 2 The wound body includes: an anode body 11 connected to a lead tab 105A, a cathode body 12 connected to a lead tab 105B, and a separator 13. A conductive polymer layer (not shown) is formed on the anode body 11. In addition, at least the conductive polymer layer of the capacitor element 10 is impregnated with a liquid component.

[0107] The anode body 11 and the cathode body 12 are wound with the separator 13 interposed therebetween. The outermost periphery of the wound body is fixed by a winding fixing tape 14. Figure 2 The diagram shows a partially unwound state before the outermost circumference of the wound body is fixed.

[0108] The electrolytic capacitor only needs to have at least one capacitor element, and may have a plurality of capacitor elements. The number of capacitor elements included in the electrolytic capacitor may be determined according to the intended use.

[0109] [Method for manufacturing electrolytic capacitor]

[0110] The electrolytic capacitor is manufactured using a manufacturing method that includes at least the following steps, namely, a step of preparing the above-mentioned liquid component, a conductive polymer impregnation step of impregnating the dielectric layer with the conductive polymer, and a liquid component impregnation step of impregnating the capacitor element with the liquid component after the conductive polymer impregnation step. The manufacturing method of the electrolytic capacitor may also include a step of adjusting the viscosity of the liquid component before the liquid component impregnation step. The manufacturing method of the electrolytic capacitor may also include a step of preparing the capacitor element and a step of sealing the capacitor element.

[0111] An example of a method for manufacturing an electrolytic capacitor is described below.

[0112] (1) Step of Preparing Capacitor Element 10

[0113] (i) Step of Preparing Anode Body 11 and Cathode Body 12 Having Dielectric Layers

[0114] A metal foil formed of a valve metal is used as a raw material for the anode body 11 and the cathode body 12. In the case of the anode body 11, the surface of the metal foil is roughened by etching treatment or the like, and a plurality of concave and convex portions are formed on the surface of the metal foil. Then, a dielectric layer is formed on the surface of the roughened metal foil by chemical conversion treatment or the like. The surface of the cathode body 12 may also be roughened as needed.

[0115] (ii) Preparation of wound body

[0116] Anode body 11 and cathode body 12 are wound with separator 13 interposed therebetween to form a wound body. Winding fixing tape 14 is placed on the outer surface of cathode body 12 located at the outermost layer of the wound body to fix the end of cathode body 12. The wound body is further subjected to chemical conversion treatment as needed.

[0117] (iii) Step of Forming Capacitor Element 10

[0118] The capacitor element 10 can be formed by impregnating the dielectric layer with a conductive polymer (conductive polymer impregnation step). For example, a liquid conductive polymer dispersion is impregnated into the dielectric layer to form a conductive polymer film covering at least a portion of the dielectric layer. Thus, a capacitor element 10 having a conductive polymer disposed between the anode body 11 and the cathode body 12 is obtained. The step of applying the polymer dispersion to the surface of the dielectric layer can be repeated two or more times.

[0119] The conductive polymer dispersion, for example, comprises a conductive polymer and a liquid medium in which the conductive polymer is dispersed. As the liquid medium, water, an organic liquid medium, or a mixture thereof can be cited. The conductive polymer dispersion may further comprise at least one of a dopant and an additive as required. When the conductive polymer dispersion comprises the first solvent, it is difficult for the dispersion to penetrate into the dielectric layer, and it is difficult for the conductive polymer to be impregnated in the dielectric layer. Therefore, it is preferred that the conductive polymer dispersion does not comprise the first solvent.

[0120] (2) Step of preparing liquid component

[0121] The liquid component can be prepared by mixing the constituent components of the liquid component. The first solvent has low solubility relative to the non-aqueous solvent, but by combining with the polyalkylene glycol component, a liquid component in which the first solvent is uniformly dissolved can be prepared. It should be noted that this step can be performed before the liquid component impregnation step, before or after preparing the capacitor element, or during the preparation of the capacitor element.

[0122] More specifically, this process may include a process of dissolving the first solvent in the polyalkylene glycol component. The first solvent and the polyalkylene glycol component are heated to a temperature higher than the melting point of these components and below the boiling point or the decomposition temperature, so that the first solvent can be dissolved in the polyalkylene glycol component. In the case where the liquid component contains other components (solute, other non-aqueous solvents, etc.), the other components can coexist at the stage of dissolving the first solvent. Once the first solvent is dissolved in the polyalkylene glycol component, it is difficult to precipitate even if it is cooled. Therefore, in the case where the liquid component contains other components, it is also possible to dissolve the first solvent in the polyalkylene glycol component by heating, cool it, and then mix the other components.

[0123] The heating temperature is, for example, 30° C. to 200° C., or 50° C. to 100° C.

[0124] (3) Step of adjusting the viscosity of the liquid component

[0125] Before the liquid component impregnation process, the viscosity of the liquid component can be adjusted. The viscosity of the liquid component is adjusted, for example, by adjusting the temperature of the liquid component. More specifically, the viscosity can be adjusted by heating the liquid component. It should be noted that this process can be performed in the process of preparing the liquid component. More specifically, the liquid component can be prepared under heating so that it can be impregnated into the capacitor element 10 in a state where the viscosity becomes low.

[0126] Preferably, this process is used to make the viscosity of the liquid component for impregnation less than 200 mPa·s, and it can also be made less than 100 mPa·s or less than 70 mPa·s. By combining the first solvent with the polyalkylene glycol component, the viscosity of the liquid component can be adjusted to this range by heating. Thus, the liquid component can be easily impregnated into the conductive polymer of the capacitor element, making it easy to ensure high film repairability of the dielectric layer, and it is easy to orient the conductive polymer to ensure high conductivity.

[0127] The temperature of the liquid component used for impregnation may be, for example, 10° C. to 120° C., 20° C. to 100° C., or 20° C. to 70° C. The temperature of the liquid component used for impregnation may be adjusted to a temperature of 50° C. to 120° C., 50° C. to 100° C., or 50° C. to 70° C. by heating the liquid component.

[0128] (4) Liquid component impregnation step

[0129] In this process, it is sufficient to impregnate the capacitor element 10 with the liquid component. Thus, an electrolytic capacitor having a conductive polymer and a liquid component can be obtained. This process is performed after the conductive polymer impregnation process. For example, the capacitor element 10 and the liquid component can be accommodated in a container so that the liquid component is impregnated in the capacitor element 10, or the capacitor element 10 can be impregnated with the liquid component by immersing it in the liquid component, or the capacitor element 10 can be impregnated with the liquid component by dripping the liquid component.

[0130] (5) Process of sealing capacitor elements

[0131] The capacitor element 10 is housed in the bottomed case 101 in such a manner that the leads 104A and 104B are located on the opening side of the bottomed case 101. The bottomed case 101 also contains a liquid component. Then, the opening of the bottomed case 101 is sealed with a sealing body 102 through which each lead passes, and the opening end is crimped to the sealing body 102, and a seat plate 103 is arranged on the crimped portion. Figure 1 The electrolytic capacitor shown.

[0132] In the above-mentioned embodiment, a winding-type electrolytic capacitor is described, but the application scope of the present invention is not limited to the above-mentioned electrolytic capacitor, and can also be applied to other electrolytic capacitors, such as a sheet-type electrolytic capacitor using a metal sintered body as an anode body, and a stacked electrolytic capacitor using a metal plate as an anode body.

[0133] Example

[0134] Hereinafter, the present invention will be specifically described based on Examples and Comparative Examples; however, the present invention is not limited to the following Examples.

[0135] 《Manufacturing of electrolytic capacitors E1 to E16 and C1 to C4》

[0136] A wound electrolytic capacitor (diameter 10 mm×length (L) 10 mm) having a rated voltage of 25 V and a rated capacitance of 330 μF was produced. A specific method for producing the electrolytic capacitor will be described below.

[0137] (Preparation of anode body)

[0138] A 100 μm thick aluminum foil was etched to roughen the surface of the aluminum foil. Then, a dielectric layer was formed on the surface of the aluminum foil by chemical conversion treatment. The chemical conversion treatment was performed by immersing the aluminum foil in an ammonium adipate solution and applying a voltage of 180 V. Then, the aluminum foil was cut to prepare an anode body.

[0139] (Preparation of cathode body)

[0140] An aluminum foil having a thickness of 50 μm was etched to roughen the surface of the aluminum foil, and then the aluminum foil was cut to prepare a cathode body.

[0141] (Production of wound body)

[0142] The anode lead connector and the cathode lead connector are connected to the anode body and the cathode body, and the anode body and the cathode body are wound with the separator interposed therebetween while the lead connector is wound in. The anode lead and the cathode lead are connected to the ends of each lead connector protruding from the wound body. The produced wound body is subjected to chemical conversion treatment again, and a dielectric layer is formed at the cut end of the anode body. Then, the end of the outer surface of the wound body is fixed with a winding fixing tape to produce a wound body.

[0143] (Preparation of polymer dispersion)

[0144] 3,4-ethylenedioxythiophene and polystyrene sulfonic acid (PSS, weight average molecular weight 100,000) as a polymer dopant were dissolved in ion exchange water to prepare a mixed solution. While stirring the mixed solution, iron (III) sulfate (oxidant) dissolved in ion exchange water was added to carry out a polymerization reaction. After the reaction, the obtained reaction solution was dialyzed to remove unreacted monomers and excess oxidant, and a polymer dispersion containing polyethylenedioxythiophene (PEDOT / PSS) doped with about 5% by mass of PSS was obtained.

[0145] (Formation of Solid Electrolyte Layer)

[0146] In a reduced pressure atmosphere (40 kPa), the wound body is immersed in a polymer dispersion contained in a predetermined container for 5 minutes, and then the wound body is lifted from the polymer dispersion. Then, the wound body impregnated with the polymer dispersion is dried in a drying oven at 150° C. for 20 minutes to form a solid electrolyte layer composed of a conductive polymer layer covering at least a portion of the dielectric layer. The capacitor element is formed by operating as described above.

[0147] (Preparation of liquid components)

[0148] The first solvent shown in Table 1 was mixed with the polyalkylene glycol component, and the mixture was heated to 95° C. under stirring to dissolve the first solvent. Triethylamine phthalate was added as a solute to the obtained mixed solvent to a concentration of 15% by mass, and mixed. In this manner, a liquid component was prepared. The SP value of glycerol was 16.5, and the SP values ​​of diglycerol and polyglycerol were 16 or more.

[0149] In the electrolytic capacitors C1 to C4, the nonaqueous solvents shown in Table 1 were used as liquid components.

[0150] (Assembly of electrolytic capacitors)

[0151] Heat the liquid component to above 60°C and adjust the viscosity to less than 200mPa·s. Place 200mg of the liquid component with adjusted viscosity in the housing together with the capacitor element, and in a reduced pressure atmosphere (40kPa), allow the liquid component to penetrate into the capacitor element for 5 minutes. Use a sealing body to seal the opening of the housing, and complete the Figure 1 The electrolytic capacitor shown in the figure was then aged at 130° C. for 2 hours while applying a rated voltage. The viscosity of the liquid component was measured using a vibration viscometer VM-100A manufactured by CBC Corporation.

[0152] A butyl polymer, a peroxide-based crosslinking agent, and an additive are kneaded and formed using a mold, and a disc-shaped elastic member containing butyl rubber is used as a sealing body. A reinforcing agent (carbon black), a crosslinking accelerator, a dispersing aid (stearic acid), a hindered phenol-based anti-aging agent, and a modifier (silane coupling agent) are used as additives. The amount of each component used is adjusted so that the content of butyl rubber as an elastic polymer component in the sealing body is the value in Table 1.

[0153] [Evaluation 1]

[0154] (ESR measurement and residual amount of liquid components)

[0155] The ESR (initial ESR) of the obtained electrolytic capacitor at a frequency of 100kHz / Ω was measured using an LCR tester. In addition, in order to evaluate long-term reliability, the ESR increase rate (ΔESR) was confirmed by maintaining the capacitor at 145°C for 2000 hours while applying the rated voltage. ΔESR is expressed as the ratio (Z / Z0×100%) of the ESR (Z) of the electrolytic capacitor maintained at 145°C to the initial value (Z0). For ESR (Z), the electrolytic capacitor maintained at 145°C was measured in the same manner as the initial ESR.

[0156] After confirming the rate of increase of ESR, the electrolytic capacitor is disassembled, the liquid component is recovered, and the mass (g) is calculated. The remaining amount of the liquid component is expressed as the ratio (m / m0×100%) of the mass (m) of the liquid component after being kept at 145°C to the mass (m0) of the initial liquid component.

[0157] Table 1 shows the evaluation results.

[0158] [Table 1]

[0159]

[0160] Polyglycerol 310: Polyglycerol with a number average molecular weight of about 310

[0161] Polyglycerol 750: polyglycerol with a number average molecular weight of about 750

[0162] PAG: Polyalkylene glycol

[0163] PEG: polyethylene glycol

[0164] PPG: Polypropylene glycol

[0165] GBL: gamma-butyrolactone

[0166] EG: Ethylene glycol

[0167] SL: Sulfolane

[0168] Industrial Applicability

[0169] The electrolytic capacitor of the present invention can be used as a hybrid electrolytic capacitor. The electrolytic capacitor is particularly suitable for applications requiring high heat resistance. However, the applications of the electrolytic capacitor are not limited to these applications.

[0170] Description of Reference Numerals

[0171] 100 electrolytic capacitor, 101 bottom casing, 102 sealing body, 103 seat plate, 104A, 104B lead wires, 105A, 105B lead wire connectors, 10 capacitor element, 11 anode body, 12 cathode body, 13 spacer, 14 winding fixing tape.

Claims

1. An electrolytic capacitor, It contains capacitor elements and liquid components. The capacitor element includes an anode body having a dielectric layer on its surface and a conductive polymer covering a portion of the dielectric layer. The liquid component comprises a first solvent and a polyalkylene glycol component, The first solvent contains at least a glycerol component, The first solvent is dissolved in the polyalkylene glycol component, The viscosity of the liquid component at 20° C. is 200 mPa·s or more.

2. The electrolytic capacitor according to claim 1, wherein: The content of the glycerin component in the liquid component is 10% by mass or more and 70% by mass or less.

3. The electrolytic capacitor according to claim 1 or 2, wherein: The content of the polyalkylene glycol component in the liquid component is greater than the content of the glycerin component in the liquid component.

4. The electrolytic capacitor according to claim 1 or 2, wherein: The glycerin component includes at least one selected from glycerin and derivatives thereof.

5. The electrolytic capacitor according to claim 1 or 2, wherein: The glycerol component comprises at least one selected from the group consisting of polyglycerol and derivatives thereof, The number of repetitions of the glycerol unit in the polyglycerol is 2 or more and 12 or less.

6. An electrolytic capacitor, It contains capacitor elements and liquid components. The capacitor element includes an anode body having a dielectric layer on its surface, a cathode body, and a conductive polymer disposed between the anode body and the cathode body. The liquid component comprises a first solvent and a polyalkylene glycol component, The solubility parameter of the first solvent is 15 (cal / cm 3 ) 1 / 2 above, The first solvent is dissolved in the polyalkylene glycol component, The viscosity of the liquid component at 20° C. is 200 mPa·s or more.

7. The electrolytic capacitor according to claim 6, wherein: The content of the first solvent in the liquid component is 10 mass % or more and 70 mass % or less.

8. The electrolytic capacitor according to claim 6, wherein: The content of the polyalkylene glycol component in the liquid component is greater than the content of the first solvent.

9. The electrolytic capacitor according to claim 1 or 6, wherein: The content of the polyalkylene glycol component in the liquid component is 30% by mass or more and 95% by mass or less.

10. The electrolytic capacitor according to claim 1 or 6, wherein: The weight average molecular weight of the polyalkylene glycol component is 200 or more and 2000 or less.

11. The electrolytic capacitor according to claim 1 or 6, wherein: The liquid component contains a solute at a ratio of 0.5 mass % or more.

12. The electrolytic capacitor according to claim 1 or 6, further comprising: a container having an opening and accommodating the capacitor element and the liquid component; and a sealing body for sealing the opening, The sealing body comprises an elastic polymer, The elastic polymer accounts for 10% by mass or more of the sealing body.

13. The electrolytic capacitor according to claim 12, wherein: The elastic polymer is cross-linked by at least one cross-linking agent selected from phenolic resin and peroxide.

14. The electrolytic capacitor according to claim 1 or 6, which is capable of ensuring a use time of 2000 hours or more at a temperature of 120°C. 15 . An electrolytic capacitor module comprising a plurality of the electrolytic capacitors according to claim 1 connected in parallel. 16 . The electrolytic capacitor module according to claim 15 , wherein the allowable current is 20 A or more.

17. A method for manufacturing an electrolytic capacitor, A method for manufacturing an electrolytic capacitor including a capacitor element and a liquid component, wherein the capacitor element includes an anode body having a dielectric layer on its surface and a conductive polymer covering a portion of the dielectric layer. The manufacturing method comprises: a step of preparing a liquid component including a first solvent containing at least a glycerol component and a polyalkylene glycol component, a conductive polymer impregnation step of impregnating the dielectric layer with the conductive polymer, and a liquid component impregnation step of impregnating the capacitor element with the liquid component after the conductive polymer impregnation step; The preparation step includes a step of dissolving the first solvent in the polyalkylene glycol component. Before the liquid component impregnation step, a step of making the viscosity of the liquid component lower than 200 mPa·s is included.

18. A method for manufacturing an electrolytic capacitor, A method for manufacturing an electrolytic capacitor including a capacitor element and a liquid component, wherein the capacitor element includes an anode body having a dielectric layer on its surface and a conductive polymer covering a portion of the dielectric layer. The manufacturing method comprises: Preparation of a solution containing a solubility parameter of 15 (cal / cm 3 ) 1 / 2 The above-mentioned step of preparing a liquid component of the first solvent and the polyalkylene glycol component, a conductive polymer impregnation step of impregnating the dielectric layer with the conductive polymer, and a liquid component impregnation step of impregnating the capacitor element with the liquid component after the conductive polymer impregnation step; The preparation step includes a step of dissolving the first solvent in the polyalkylene glycol component. Before the liquid component impregnation step, a step of making the viscosity of the liquid component lower than 200 mPa·s is included.

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