TW201812811A - Electrolytic capacitor - Google Patents

Abstract

The purpose of the present invention is to provide an electrolytic capacitor which raises no concerns regarding an outer case swelling or rupturing even in cases where a large quantity of hydrogen gas is generated, has a large capacitance, and can enable a reduction in size and an increase in withstand voltage. This electrolytic capacitor is provided with a hydrogen discharge film, with the hydrogen discharge film including a hydrogen gas-permeable layer that selectively allows permeation of 99 mol.% of hydrogen gas when in contact with a mixed gas containing equimolar quantities of hydrogen gas and nitrogen gas, and the electrolytic capacitor is characterized in that the ratio of the average thickness of an oxide film on an anode to the rated voltage of the capacitor (average thickness/rated voltage) is 1.2-2.9 (nm/V).

Description

Electrolytic capacitor

The present invention relates to an electrolytic capacitor having a hydrogen discharge film.

In recent years, electrolytic capacitors such as aluminum electrolytic capacitors have been used in applications such as inverters and storage batteries for wind power generation and solar power generation, and large power supplies. For example, the anode of an aluminum electrolytic capacitor has an aluminum oxide film that is electrochemically formed on the surface of an aluminum electrode. When an aluminum electrolytic capacitor is used, if excessive stresses, mechanical stresses such as vibration and shock, or electrical stresses such as reverse voltage, overvoltage, and overcurrent are applied to the anode, a defective portion is generated in the alumina film. Aluminum electrolytic capacitors use an electrolyte with excellent film repairability. The aluminum oxide film is quickly formed by the reaction of the electrolyte with the anode's aluminum to repair defective parts. However, at this time, oxidation occurs on the anode side and reduction occurs on the cathode side, thereby generating hydrogen. If a large number of defective portions are generated in the alumina film, a large amount of hydrogen is generated due to the film repairing action, and there is a possibility that the external case may swell or rupture due to an increase in the internal pressure of the aluminum electrolytic capacitor. Therefore, a safety valve with a special film is provided in a common electrolytic capacitor. In addition to the function of venting hydrogen inside the capacitor to the outside, the safety valve has the function of self-disintegration to reduce the internal pressure when the internal pressure of the capacitor sharply rises, preventing the capacitor from rupturing itself. As a special film which is a constituent member of such a safety valve, the following are proposed, for example. Patent Document 1 proposes a pressure adjustment film including a foil tape including a palladium-silver (Pd-Ag) alloy made of 20 wt% (19.8 mol%) Ag in palladium. However, the foil tape of Patent Document 1 has a problem of being easily embrittlement in an environment of about 50 to 60 ° C. or lower, and the function as a pressure-adjusting film cannot be maintained for a long time, so that it has not been put into practical use. In order to solve the above-mentioned problem, Patent Document 2 proposes a hydrogen-removing film, which includes a Pd-Ag alloy, and the Ag content in the Pd-Ag alloy is 20 mol% or more. In addition, Patent Document 3 proposes a hydrogen removal film including a Pd-Cu alloy, and the content of Cu in the Pd-Cu alloy is 30 mol% or more. In addition, in order to suppress the occurrence of defect portions in the oxide film, the ordinary electrolytic capacitor increases the film thickness of the oxide film. However, since the oxide film is formed electrochemically, there is a disadvantage that increasing the film thickness of the oxide film requires more energy or manufacturing time. In addition, if the film thickness of the oxide film is increased, the electrostatic capacitance of the capacitor is reduced. Therefore, in order to compensate for the decrease in the electrostatic capacitance, the surface area of the oxide film must be increased, which makes it difficult to miniaturize the electrolytic capacitor. [Prior Art Literature] [Patent Literature] [Patent Literature 1] Japanese Patent No. 4280014 [Patent Literature 2] International Publication No. 2014/098038 [Patent Literature 3] International Publication No. 2015/019906

[Problems to be Solved by the Invention] The present invention has been developed in view of the above-mentioned problems, and an object thereof is to provide an external casing that is free from expansion or cracking even when a large amount of hydrogen is generated, and the electrostatic capacitance is relatively small. Large electrolytic capacitors that can be miniaturized or withstand high voltage. [Technical means for solving the problem] The present invention relates to an electrolytic capacitor, which is characterized in that it is provided with a hydrogen-removing film, and the hydrogen-removing film is included in contact with a mixed gas containing hydrogen and nitrogen, which is selective. A hydrogen permeable layer that allows more than 99 mol% of hydrogen to pass through, and the ratio of the average thickness of the anode oxide film to the rated voltage of the capacitor (average thickness / rated voltage) is 1.2 to 2.9 (nm / V). The ratio of the average thickness of the oxide film of the anode to the rated voltage of the capacitor (average thickness / rated voltage) of the electrolytic capacitor of the present invention is 1.2 to 2.9 (nm / V). Compared with the previous electrolytic capacitor, the above ratio is smaller ( That is, the average thickness of the oxide film is thinner than that of the conventional electrolytic capacitor). If the ratio of the average thickness of the oxide film of the anode to the rated voltage of the capacitor is reduced in the manner of the present invention, defects are easily generated in the oxide film due to mechanical stress or electrical stress, and a large amount is generated due to the repair effect of the film. Hydrogen, due to the increase in the internal pressure of the electrolytic capacitor, may increase the possibility of expansion or cracking of the external case. However, the electrolytic capacitor of the present invention is provided with a hydrogen discharge film including a hydrogen permeation layer. The hydrogen permeation layer is used to selectively permeate 99 mol% or more of hydrogen gas when a mixed gas containing hydrogen and nitrogen is formed. Therefore, even if a large amount of hydrogen is generated inside the electrolytic capacitor, the hydrogen can be quickly discharged only to the outside, which can effectively prevent the external case from expanding or rupturing. When the ratio of the average thickness of the oxide film on the anode to the rated voltage of the capacitor does not reach 1.2 (nm / V), there is a large amount of hydrogen generated in the electrolytic capacitor in a short time that exceeds the hydrogen discharge capacity of the hydrogen discharge film described above. This may increase the risk of expansion or cracking of the external case, or make it difficult to increase the withstand voltage of the electrolytic capacitor. On the other hand, if it exceeds 2.9 (nm / V), it becomes difficult to increase the electrostatic capacitance of the electrolytic capacitor, or it becomes difficult to miniaturize the electrolytic capacitor. The hydrogen permeable layer is preferably a metal layer, more preferably a Pd alloy layer. The Pd alloy, which is a material for forming the Pd alloy layer, preferably contains 20 to 65 mol% of a Group 11 element from the viewpoints of excellent hydrogen removal performance, oxidation resistance, and embrittlement resistance during hydrogen storage. The Group 11 element is preferably at least one selected from the group consisting of Au, Ag, and Cu. In particular, from the viewpoint of excellent chemical resistance, Au is preferred. The Pd alloy layer containing Pd-group 11 element alloy has the following functions: dissociating hydrogen molecules into hydrogen atoms on the surface of the film, dissolving the hydrogen atoms in the film, and diffusing the dissolved hydrogen atoms from the high-pressure side to the low-pressure side On the low-pressure side of the membrane surface, hydrogen atoms are converted into hydrogen molecules again and discharged. When the content of the Group 11 element is less than 20 mol%, the strength of the Pd alloy may be insufficient, or the above-mentioned function may be difficult to appear. When it exceeds 65 mol%, the hydrogen transmission rate may be reduced. . The metal layer preferably has a support on one or both sides. The support system is provided in order to prevent the metal layer from falling into the electrolytic capacitor when the safety valve or the hydrogen exhaust valve falls off. In addition, when the metal layer has a function as a self-crashing safety valve when the internal pressure of the electrolytic capacitor becomes a certain value or more, if the metal layer is a thin film, the mechanical strength of the metal layer is low. There is a risk that the internal pressure will collapse before it reaches a certain value, so that it cannot function as a safety valve. Therefore, when the metal layer is a thin film, in order to improve the mechanical strength, it is preferably on a single-sided or two-area layer support of the metal layer. Examples of the electrolytic capacitor include an aluminum electrolytic capacitor, a tantalum electrolytic capacitor, and a niobium electrolytic capacitor. [Effects of the Invention] The electrolytic capacitor of the present invention has a thinner average thickness of the oxide film than the previous electrolytic capacitor. Therefore, the electrolytic capacitor of the present invention has the advantage that the electrostatic capacitance is larger than that of the previous electrolytic capacitor, although it is the same size. In addition, the electrolytic capacitor of the present invention can achieve the advantages of miniaturization and high withstand voltage even if the electrolytic capacitor has the same degree of electrostatic capacitance as the conventional electrolytic capacitor. In addition, although the electrolytic capacitor of the present invention has a thinner average thickness of the oxide film than the conventional electrolytic capacitor, it can be manufactured with less energy and manufacturing time than before, and is excellent in cost. The electrolytic capacitor of the present invention is provided with a hydrogen-removing film that does not easily decrease hydrogen-exhausting property even after long-term use, and can stably discharge hydrogen. In addition, the above-mentioned hydrogen discharge film can not only quickly discharge hydrogen generated inside the electrolytic capacitor to the outside, but also can prevent impurities from entering the electrolytic capacitor from the outside. In addition, the above-mentioned hydrogen discharge film may have a function of preventing the electrolytic capacitor itself from rupturing by being collapsed to reduce the internal pressure when the internal pressure of the electrolytic capacitor rises sharply. By virtue of these effects, the initial performance of the electrolytic capacitor can be maintained for a long time, so that the life of the electrolytic capacitor can be extended.

Hereinafter, embodiments of the present invention will be described. The electrolytic capacitor of the present invention includes a hydrogen-removing film, and the hydrogen-removing film includes a hydrogen-permeating layer which selectively transmits 99 mol% or more of hydrogen when contacting a mixed gas containing hydrogen and nitrogen, etc. The electrolytic capacitor of the present invention is characterized in that the ratio (average thickness / rated voltage) of the average thickness of the oxide film of the anode to the rated voltage of the capacitor is 1.2 to 2.9 (nm / V). Examples of the electrolytic capacitor include an aluminum electrolytic capacitor, a tantalum electrolytic capacitor, and a niobium electrolytic capacitor, but an aluminum electrolytic capacitor is particularly preferred. The constituent members other than the hydrogen discharge film and the anode can be used without particular limitation. In addition, the electrolytic capacitor of the present invention can be manufactured by a conventional method in addition to the following hydrogen-removing film and anode. Hereinafter, the hydrogen discharge film and the anode will be described in detail. The above-mentioned hydrogen-removing film includes a hydrogen-permeable layer that selectively transmits 99 mol% or more of hydrogen when a mixed gas containing hydrogen and nitrogen is equimolarly contacted. A hydrogen-permeable layer that selectively transmits 99.9 mol% or more of hydrogen is preferred. In addition, the square root of the pressure of the above-mentioned hydrogen discharge membrane is 76.81 Pa ^1/2 (0.059 bar), and the hydrogen permeability is preferably 10 ml / day or more (4.03 × 10 ^-4 mol / day or more: according to SATP (Standard Temperature And Pressure). (Standard temperature and pressure) calculations (the volume of an ideal gas of 1 mol at a temperature of 25 ° C and an air pressure of 1 bar is 24.8 L)). The hydrogen transmission coefficient of the above-mentioned hydrogen removal film system at 50 ° C is preferably 1 × 10 ^-12 (mol · m ^-1 · sec ^-1 · Pa ^-1/2 ) or more, and more preferably 1 × 10 ^-10 ( mol · m ^-1 · sec ^-1 · Pa ^-1/2 ) or more, and more preferably 1 × 10 ^-9 (mol · m ^-1 · sec ^-1 · Pa ^-1/2 ) or more. Examples of the layer having such characteristics include a metal layer such as a Pd alloy layer. The other metals forming the Pd alloy as the material of the Pd alloy layer are not particularly limited, but examples thereof include Nb, V, Ta, Ni, Fe, Al, Cu, Ru, Re, Rh, Au, Pt, Ag, and Cr , Co, Sn, Zr, Y, Ce, Ti, Ir, and Mo. These other metals may be used alone or in combination of two or more. It is preferable to use a Group 11 element among these, more preferably at least one selected from the group consisting of Au, Ag, and Cu among these. In particular, a Pd-Au alloy is preferable because it has excellent corrosion resistance to an electrolytic solution inside an electrolytic capacitor or a gas component generated from a self-constituting member. The Pd alloy preferably contains 20 to 65 mol% of the Group 11 element, more preferably 30 to 65 mol%, and even more preferably 30 to 60 mol%. In addition, the Pd alloy layer containing a Pd-Ag alloy with an Ag content of 20 mol% or more, a Pd-Cu alloy with a Cu content of 30 mol% or more, or a Pd-Au alloy with an Au content of 20 mol% or more is even 50 to 50%. The low temperature range below about 60 ° C is also not easily embrittled by hydrogen, so it is preferable. In addition, the Pd alloy may include a group IB and / or group IIIA metal as long as the effect of the present invention is not impaired. The Pd alloy may be not only a two-component alloy containing Pd, but also a three-component alloy such as Pd-Au-Ag, and may also be a three-component alloy including Pd-Au-Cu. Furthermore, it may be a 4-component alloy of Pd-Au-Ag-Cu. For example, in the case of a multi-component alloy containing Pd, Au, and other metals, the total content of Au and other metals in the Pd alloy is preferably 55 mol% or less, more preferably 50 mol% or less, and even more preferably 45 mol% or less, particularly preferably 40 mol% or less. The Pd alloy layer can be produced by, for example, a rolling method, a sputtering method, a vacuum evaporation method, an ion plating method, or a plating method. However, in the case of manufacturing a thick Pd alloy layer, it is preferably The rolling method is used, and when a Pd alloy layer having a thin film thickness is produced, a sputtering method is preferably used. The rolling method may be either hot rolling or cold rolling. The calendering method is a method in which a pair or a plurality of pairs of rollers (rollers) are rotated, and a metal serving as a raw material is pressed between the rollers while being processed to form a film. The film thickness of the Pd alloy layer obtained by the rolling method is preferably 5 to 50 μm, and more preferably 10 to 30 μm. When the film thickness is less than 5 μm, pinholes or cracks are liable to occur during production, or if hydrogen storage is performed, deformation is likely to occur. On the other hand, if the film thickness exceeds 50 μm, it takes time to permeate hydrogen, so the hydrogen permeability is lowered, or the cost is poor, which is not good. The sputtering method is not particularly limited, and can be performed using sputtering devices such as a parallel flat plate type, a single piece type, a through type, a DC (Direct Current) sputtering, and an RF (Radio Frequency) sputtering. For example, after the substrate is mounted on a sputtering device provided with a metal target, the inside of the sputtering device is evacuated, the Ar gas pressure is adjusted to a specific value, and a specific sputtering current is applied to the metal target to form Pd on the substrate. Alloy film. Thereafter, the Pd alloy film was peeled from the substrate to obtain a Pd alloy layer. As the target, a single or a plurality of targets may be used depending on the Pd alloy layer to be manufactured. Examples of the substrate include glass plates, ceramic plates, silicon wafers, metal plates such as aluminum and stainless steel. The film thickness of the Pd alloy layer obtained by the sputtering method is preferably 0.01 to 5 μm, and more preferably 0.05 to 2 μm. When the film thickness is less than 0.01 μm, it is not only possible to form pinholes, but also it is difficult to obtain the required mechanical strength. Moreover, it is easy to break when peeling from a board | substrate, and handling after peeling also becomes difficult. On the other hand, if the film thickness exceeds 5 μm, it takes time to manufacture the Pd alloy layer, which is inferior in terms of cost, which is not preferable. The film area of the Pd alloy layer can be appropriately adjusted in consideration of the amount of hydrogen permeation and the film thickness, but when it is used as a constituent member of a safety valve, it is about 0.01 to 100 mm ² . In addition, in the present invention, the film area of the Pd alloy layer is the area of the portion of the Pd alloy layer where hydrogen is actually discharged, and does not include the portion coated with the following ring-shaped adhesive. The metal layer is preferably provided with a coating on one or both sides. Due to the coating provided on one or both sides of the metal layer, pinholes or cracks existing in the metal layer can be blocked. This makes it possible to suppress leakage of necessary components (such as an electrolytic solution) inside the electrochemical device to the outside. The raw material of the coating layer is not particularly limited, and examples thereof include fluorine-based compounds, rubber-based polymers, silicone-based polymers, urethane-based polymers, and polyester-based polymers. Among them, it is preferable to use at least one compound selected from the group consisting of a fluorine-based compound, a rubber-based polymer, and a silicone-based polymer from the viewpoint that the hydrogen permeability of the hydrogen-removing film is not easily hindered. . Examples of the fluorine-based compound include a fluoroalkyl-containing compound such as a fluoroalkyl carboxylate, a fluoroalkyl quaternary ammonium salt, and a fluoroalkyl ethylene oxide adduct; a perfluoroalkyl carboxylate, Perfluoroalkyl quaternary ammonium salts, perfluoroalkyl ethylene oxide adducts, and other compounds containing perfluoroalkyl groups; tetrafluoroethylene / hexafluoropropylene copolymers, and tetrafluoroethylene / perfluoroalkylethylene Fluorocarbon-based compounds such as ethylene ether copolymers; Tetrafluoroethylene polymers; Copolymers of vinylidene fluoride and tetrafluoroethylene; Copolymers of vinylidene fluoride and hexafluoropropylene; Fluorinated (meth) acrylates ; Fluorine-containing (meth) acrylate polymers; fluorine-containing (meth) acrylate alkyl ester polymers; copolymers of fluorine-containing (meth) acrylates and other monomers, and the like. In addition, as the fluorine-based compound as a raw material of the coating layer, "DURASURF" series manufactured by Harvests Corporation, "OPTOOL" series manufactured by DAIKIN INDUSTRIES, and "KY-100" series manufactured by Shin-Etsu Chemical Industry Co., Ltd. can also be used. Examples of the rubber-based polymer include natural rubber, styrene butadiene rubber, acrylonitrile butadiene rubber, chloroprene rubber, polyisoprene rubber, polybutadiene rubber, ethylene propylene rubber, and ethylene. -Propylene-diene terpolymer rubber, chlorinated polyethylene rubber, and ethylene-vinyl acetate copolymer rubber. In addition, as a raw material of the coating layer, which is a rubber-based polymer, "ELEPCOAT" series manufactured by Nittashinko Co., Ltd. can also be used. Examples of the silicone-based polymer include polydimethylsiloxane, alkyl-modified polydimethylsiloxane, carboxy-modified polydimethylsiloxane, and amino-modified polydimethylsiloxane Oxane, epoxy-modified polydimethylsiloxane, fluorine-modified polydimethylsiloxane, and (meth) acrylate-modified polydimethylsiloxane. The coating layer can be formed, for example, by applying a coating raw material composition to a metal layer and hardening it. The coating method is not particularly limited, and examples thereof include a roll coating method, a spin coating method, a dip coating method, a spray coating method, a bar coating method, a blade coating method, a die coating method, an inkjet method, And gravure coating. The solvent may be appropriately selected according to the raw material of the coating. When a fluorine-based compound is used as a raw material for the coating, for example, a fluorine-based solvent, an alcohol-based solvent, an ether-based solvent, an ester-based solvent, and a hydrocarbon-based solvent may be used alone or in combination. It is preferable to use a fluorinated solvent which is non-flammable and rapidly volatilized among these, alone or mixed with other solvents. Examples of the fluorine-based solvent include hydrofluoroether, perfluoropolyether, perfluoroalkane, hydrofluoropolyether, hydrofluorocarbon, perfluorocyclic ether, perfluorocycloalkane, hydrofluorocycloalkane, and hexafluoroxylene. , Hydrochlorofluorocarbons, and perfluorocarbons. The thickness of the coating layer is not particularly limited, but is preferably 0.1 to 40 μm, more preferably 0.2 to 10 μm, and still more preferably 0.3 to 5 μm. A support may also be provided on one or both sides of the metal layer. In particular, since the Pd alloy layer obtained by the sputtering method has a thin film thickness, it is preferably a single-sided or two-area layer support on the Pd alloy layer to improve mechanical strength. 1 and 2 are schematic cross-sectional views showing the structure of the hydrogen discharge film 1. As shown in FIG. 1 (a) or (b), a ring-shaped adhesive 3 can be used on the single-sided or two-area layer support 4 of the Pd alloy layer 2, or as shown in FIG. 2 (a) or (b) A jig 5 is used on the single-sided or two-area layer support 4 of the Pd alloy layer 2. The support 4 is not particularly limited as long as it is hydrogen-permeable and can support the Pd alloy layer 2. The support 4 may be a non-porous body or a porous body. The support 4 may be woven or non-woven. Examples of the forming material of the support 4 include polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polyethylene naphthalate, and polyarylene ethers such as polyfluorene and polyetherfluorene. Fluorine resins such as gadolinium, polytetrafluoroethylene and polyvinylidene fluoride, epoxy resins, polyimide, polyimide, etc. Among them, chemically and thermally stable polyfluorene or polytetrafluoroethylene can be preferably used. The support 4 is preferably a porous body having an average pore diameter of 100 μm or less. If the average pore diameter exceeds 100 μm, the surface smoothness of the porous body is reduced. Therefore, when a Pd alloy layer is manufactured by a sputtering method or the like, it becomes difficult to form a uniform Pd alloy layer on the porous body, or It becomes easy to generate pinholes or cracks in the Pd alloy layer. The thickness of the support 4 is not particularly limited, but is usually about 5 to 1000 μm, and preferably 10 to 300 μm. When the Pd alloy layer 2 is manufactured by the sputtering method, if the support 4 is used as the substrate, the Pd alloy layer 2 can be directly formed on the support 4 so that the row can be manufactured without using the adhesive 3 or the jig 5. The hydrogen film 1 is preferable from the viewpoint of the physical properties and production efficiency of the hydrogen discharge film 1. In this case, as the support 4, it is preferable to use a porous body having an average pore diameter of 100 μm or less, more preferably a porous body having an average pore diameter of 5 μm or less, and it is particularly preferable to use an ultrafiltration membrane (UF (Ultrafiltration Membrane)). membrane). The shape of the above-mentioned hydrogen discharge film may be a substantially circular shape, or a polygon such as a triangle, a quadrangle, or a pentagon. It can be set to arbitrary shapes according to the following uses. The above-mentioned hydrogen discharge film functions as a constituent member of a safety valve of an electrolytic capacitor. In addition, the hydrogen discharge film may be provided in the electrolytic capacitor as a hydrogen discharge valve separately from the safety valve. The above-mentioned hydrogen-removing film does not become brittle at low temperatures, and therefore has an advantage that it can be used at a temperature of 150 ° C or lower, and further, a temperature of 110 ° C or lower. That is, it can be suitably used as a safety valve or a hydrogen exhaust valve of an electrolytic capacitor which cannot be used at a high temperature (for example, 400 to 500 ° C). The ratio of the average thickness of the anode oxide film used in the electrolytic capacitor of the present invention to the rated voltage of the capacitor (average thickness / rated voltage) is 1.2 to 2.9 (nm / V), preferably 1.3 to 2.4 (nm / V) , More preferably 1.4 to 2.0 (nm / V). For example, in the case of an ordinary aluminum electrolytic capacitor with a rated voltage of 400 (V), the average thickness of the aluminum oxide film is about 1200 nm, and the average thickness / rated voltage is about 3 (nm / V). Therefore, when the rated voltage is the same, the average thickness of the oxide film of the anode of the electrolytic capacitor of the present invention is only 40 to 95% of the average thickness of the previous oxide film, which is extremely thin. When an anode having such an extremely thin oxide film is used as the anode of a previous electrolytic capacitor, a large number of defective parts are generated in the oxide film due to mechanical stress or electrical stress, and a large amount is generated due to the repair effect of the film Hydrogen, due to the increase in the internal pressure of the electrolytic capacitor, causes the external casing to expand or rupture. However, in the present invention, the above-mentioned hydrogen discharge film is provided in the electrolytic capacitor, and therefore, even when an anode having such an extremely thin oxide film is used, the external case does not swell or crack. The average thickness of the oxide film can be adjusted to the target thickness by arbitrarily adjusting the chemical treatment voltage in the chemical treatment step (oxide film formation step). [Examples] The present invention will be described below with reference to examples, but the present invention is not limited to these examples. Manufacturing Example 1 [Production of Pd-Au alloy layer (Au content 30 mol%) by rolling method] Pd and Au raw materials were weighed so that the Au content in the ingot became 30 mol%, and put into water-cooled copper In an arc melting furnace of a crucible, arc melting is performed in an atmospheric Ar atmosphere. The obtained button-shaped ingot was cold-rolled to a thickness of 5 mm using a two-stage calender with a roll diameter of 100 mm to obtain a plate. Thereafter, the rolled sheet was placed in a glass tube, and both ends of the glass tube were sealed. The inside of the glass tube was decompressed to 5 × 10 ^-4 Pa at room temperature, and thereafter, the temperature was raised to 700 ° C. and left for 24 hours, and then cooled to room temperature. By this heat treatment, segregation of Pd and Au in the alloy is eliminated. Next, the sheet was cold-rolled to a thickness of 100 μm using a two-stage calender with a roll diameter of 100 mm, and further, the sheet was cold-rolled to a thickness of 20 μm using a two-stage calender with a roll diameter of 20 mm. Thereafter, the rolled sheet was placed in a glass tube, and both ends of the glass tube were sealed. The inside of the glass tube was decompressed to 5 × 10 ^-4 Pa at room temperature, and thereafter, the temperature was raised to 500 ° C. and left for 1 hour, and then cooled to room temperature. By this heat treatment, the internal strain of the Pd-Au alloy generated by rolling is removed, and a Pd-Au alloy layer having a thickness of 20 μm and an Au content of 30 mol% is prepared. Thereafter, a coating raw material composition (DURASURF DS-3302TH, manufactured by Harves Co., Ltd.) was applied on the Pd-Au alloy layer by a dip coating method, and dried to form a coating layer having a thickness of 0.3 μm to prepare a row. Hydrogen film. Manufacturing Example 2 [Production of Pd-Au alloy layer (Au content 50 mol%) by sputtering method] An RF magnetron sputtering device (Sanyu-electron) equipped with a Pd-Au alloy target having an Au content of 50 mol% Polyurethane porous sheet (manufactured by Nitto Denko Corporation, having a pore diameter of 0.001 to 0.02 μm) as a support. After that, the inside of the sputtering device was evacuated to 1 × 10 ^-5 Pa or less, and a sputtering current of 4.8 A was applied to the Pd-Au alloy target at an Ar gas pressure of 1.0 Pa. A Pd-Au alloy layer (Au content 50 mol%) was formed with a thickness of 100 nm. Thereafter, a coating raw material composition (DURASURF DS-3302TH, manufactured by Harves Co., Ltd.) was applied on the Pd-Au alloy layer by a dip coating method, and dried to form a coating layer having a thickness of 0.3 μm to prepare a row. Hydrogen film. Example 1 [Production of Aluminum Electrolytic Capacitor] For a 90 μm-thick medium- and high-voltage chemically treated foil (manufactured by Japan Storage Battery Industry Co., Ltd.) with a rated voltage of 200 to 450 V, a slice was cut into a square (45 × 45 mm) as the anode. For cathode foils (manufactured by Nippon Accumulator Co., Ltd.) with a thickness of 30 μm, slices with a square (45 × 45 mm) provided with protrusions to draw out the electrodes are used as cathodes. A 70 μm hemp paper (manufactured by Nippon Kogyo Paper Industry Co., Ltd.) was sliced into a square (50 × 50 mm) larger than the electrode foil as electrolytic paper. Then, the anode and the cathode are overlapped with the square portions of the electrodes aligned, and the electrolytic paper is sandwiched between the anode and the cathode to form a capacitor element. At this time, in order to prevent the electrodes from being short-circuited, the protruding portions of the electrodes are arranged so as not to overlap. The external housing of the storage element is an aluminum laminate formed by using two nylon resin films with a thickness of 40 μm, aluminum foil with a thickness of about 50 μm, and hot-melt polypropylene resin with a thickness of 30 μm. The film (manufactured by Dainippon Printing Co., Ltd.) was cut into a square shape (65 × 130 mm). Here, an opening portion of f10 is provided in a central portion of an aluminum laminated film, and the hydrogen-removing film of f20 produced in Production Example 1 is attached from a polypropylene resin film surface using an adhesive to cover the opening portion. The two aluminum laminated films were overlapped such that the polypropylene resin surfaces of the films were superimposed on each other, and 3 sides were heat-sealed (200 ° C) with a width of 10 mm to produce an external casing. Then, after the capacitor element was placed in the external case from the remaining side without heat sealing, an ethylene glycol-based electrolyte containing ammonium sebacate as the main solute was injected. Next, after the electrolyte was injected, the remaining one side which was not heat-sealed was also hot-melted with a width of 10 mm to obtain an aluminum electrolytic capacitor. Example 2 [Production of Aluminum Electrolytic Capacitor] In Example 1, instead of the hydrogen-removing film of f20 produced in Production Example 1, the hydrogen-removing film of f20 produced in Production Example 2 was used. In the same manner as in Example 1, an aluminum electrolytic capacitor was obtained. Example 3 [Production of Aluminum Electrolytic Capacitor] In Example 1, except that the size of the anode and the cathode was changed to 39 × 39 mm, an aluminum electrolytic capacitor was obtained by the same method as in Example 1. Example 4 [Production of Aluminum Electrolytic Capacitor] In Example 3, instead of the hydrogen-removing film of f20 produced in Production Example 1, the hydrogen-removing film of f20 produced in Production Example 2 was used. In the same manner as in Example 3, an aluminum electrolytic capacitor was obtained. Comparative Example 1 [Production of Aluminum Electrolytic Capacitor] In Example 1, the opening portion of f10 was not provided in the central portion of the aluminum laminated film, and the hydrogen exhaust film of f20 produced in Production Example 1 was not used. An aluminum electrolytic capacitor was obtained in the same manner as in Example 1. Comparative Example 2 [Production of Aluminum Electrolytic Capacitor] In Example 3, the opening portion of f10 was not provided in the central portion of the aluminum laminated film, and the hydrogen exhaust film of f20 produced in Production Example 1 was not used. In the same manner as in Example 3, an aluminum electrolytic capacitor was obtained. [Measurement and evaluation method] (Evaluation of hydrogen permeability) The produced hydrogen-removing film was mounted on a VCR (Vacuum Coupling Radius Seal) manufactured by Swagelok, and a SUS (Steel) was mounted on one side. Use Stainless) tube to make a sealed space (63.5 ml). After decompressing the inside of the tube with a vacuum pump, adjust it so that the pressure of hydrogen becomes 0.15 MPa, and monitor the pressure change in the environment at 105 ° C. The mole number (volume) of hydrogen passing through the hydrogen discharge membrane is known from the pressure change, so it is converted into the permeation amount per day, and the hydrogen permeation amount is calculated. For example, when the pressure changes from 0.15 MPa to 0.05 MPa (change amount of 0.10 MPa) within 2 hours, the volume of hydrogen passing through the hydrogen discharge membrane is 63.5 ml. Therefore, the hydrogen permeation amount per day is 63.5 × 24/2 = 762 ml / day. The hydrogen permeation capacity of the hydrogen removal membrane is preferably 10 ml / day or more, and more preferably 100 ml / day or more. The hydrogen permeation amount of the hydrogen discharge film of Production Example 1 was 600 ml / day, and the hydrogen permeation amount of the hydrogen discharge film of Production Example 2 was 250 ml / day. (Evaluation of selective permeability of hydrogen) The produced hydrogen-removing film was mounted on a VCR joint manufactured by Swagelok, and a SUS tube was installed on one side to produce a sealed space (63.5 ml). After the inside of the tube was decompressed by a vacuum pump, the pressure was adjusted so that the pressure of nitrogen became 150 kPa, and the pressure change under an environment of 105 ° C was monitored. The mole number (volume) of nitrogen passing through the hydrogen-removing membrane is known from the pressure change. Therefore, it is converted into the permeation amount per day, and the nitrogen permeation amount is calculated. For example, when the pressure changes from 150 kPa to 149 kPa within 2 hours (amount of change 1 kPa), the volume of nitrogen passing through the hydrogen discharge membrane is 0.635 ml. Therefore, the nitrogen permeation amount per day becomes 0.635 × 24/2 = 7.62 ml / day. The selective permeability of hydrogen is expressed by (hydrogen permeability-nitrogen permeability) ÷ hydrogen permeability × 100. In the above case, it becomes (762-7.62) ÷ 762 × 100 = 99%. The nitrogen permeation amount of the hydrogen discharge film of Production Example 1 was 0 ml / day, and the nitrogen permeation amount of the hydrogen discharge film of Production Example 2 was 0 ml / day. Therefore, the selective permeability of the hydrogen gas of the hydrogen removal film of Production Example 1 is 100%, and the selective permeability of the hydrogen gas of the hydrogen removal film of Production Example 2 is 100%. (Measurement of electrostatic capacitance and tan δ, evaluation of appearance change) In a 105 ° C environment, the charge and discharge system controller PFX2511S manufactured by Kikusui Electronics Industry Co., Ltd. was used for Examples 1 to 4, Comparative Examples 1 and 2 The aluminum electrolytic capacitor is applied with a DC voltage of 200 ~ 600 V for 10 hours. Thereafter, an LCR (Inductance Capacitance Resistance) meter E4980A manufactured by Keysight Technologies was used to measure the electrostatic capacitance (120 Hz) and tan δ (120 Hz) at 20 ° C, and the appearance change was observed. Evaluation. The results are shown in Tables 1 and 2. : No change from the initial stage. X: Swelling compared with the initial stage. [Table 1] [Table 2] The aluminum electrolytic capacitors of Examples 1 and 2 have no change in the external case even if the value of the average thickness of the oxide film / rated voltage is reduced. As the reason, it can be considered that the aluminum electrolytic capacitors of Examples 1 and 2 are provided with a special hydrogen discharge film, and hydrogen generated in the capacitor is quickly discharged to the outside by the hydrogen discharge film, thereby effectively suppressing the capacitor. Rising internal pressure. On the other hand, in the aluminum electrolytic capacitors of Comparative Examples 1 and 2, when the value of the average thickness of the oxide film / rated voltage is set to 2.8 or less, the external case expands. For this reason, it can be considered that the aluminum electrolytic capacitors of Comparative Examples 1 and 2 do not have a special hydrogen discharge film, and therefore, the hydrogen generated in the capacitor cannot be quickly discharged to the outside, and the internal pressure of the capacitor is greatly increased. In addition, the aluminum electrolytic capacitors manufactured by using anode foils with a rated voltage of 200 V in Examples 1 and 2 had a higher voltage than those manufactured by using anode foils with a rated voltage of 250 V when a voltage exceeding 200 V was applied. It is known that the electrostatic capacitance of electrolytic capacitors can achieve high withstand voltage and high electrostatic capacitance of aluminum electrolytic capacitors by using a special hydrogen discharge film without accompanying appearance changes. As in Examples 1 and 2, even in the aluminum electrolytic capacitors of Examples 3 and 4, even if the value of the average thickness of the oxide film / rated voltage is reduced, the external case remains unchanged. As the reason, it can be considered that the aluminum electrolytic capacitors of Examples 3 and 4 have a special hydrogen discharge film, and the hydrogen discharge generated in the capacitor is quickly discharged to the outside by the hydrogen discharge film, thereby effectively suppressing the capacitor. Rising internal pressure. In addition, the aluminum electrolytic capacitors manufactured by using the anode foil with a rated voltage of 200 V in Examples 3 and 4 have the same conditions as those of the anode foils manufactured by using the anode voltage of 250 V when the voltage exceeding 200 V is applied. The resulting capacitor has the same electrostatic capacitance, so it is known that the miniaturization of aluminum electrolytic capacitors can be achieved by using a special hydrogen discharge film without accompanying appearance changes. [Industrial Applicability] The electrolytic capacitor of the present invention is preferably used for various power sources and the like.

1‧‧‧Exhaust hydrogen film

2‧‧‧Pd alloy layer

3‧‧‧ Adhesive

4‧‧‧ support

5‧‧‧ jig

1 (a) and 1 (b) are schematic cross-sectional views showing the structure of a hydrogen-removing film of the present invention. 2 (a) and 2 (b) are schematic cross-sectional views showing other structures of the hydrogen discharge film of the present invention.

Claims (8)

An electrolytic capacitor is characterized in that it is provided with a hydrogen-removing film. The hydrogen-removing film is included when a mixed gas containing hydrogen and nitrogen that is unequivocally in contact is allowed to selectively transmit more than 99 mol% of hydrogen. The hydrogen permeable layer, and the ratio of the average thickness of the oxide film of the anode to the rated voltage of the capacitor (average thickness / rated voltage) is 1.2 to 2.9 (nm / V). The electrolytic capacitor of claim 1, wherein the hydrogen-permeating layer is a metal layer. The electrolytic capacitor of claim 2, wherein the metal layer is a Pd alloy layer. For example, the electrolytic capacitor of claim 3, wherein the Pd alloy as the forming material of the Pd alloy layer contains 20 to 65 mol% of the Group 11 element. The electrolytic capacitor of claim 4, wherein the Group 11 element is at least one selected from the group consisting of Au, Ag, and Cu. The electrolytic capacitor of claim 4, wherein the above-mentioned Group 11 element is Au. The electrolytic capacitor of claim 2, wherein the metal layer has a support on one or both sides. The electrolytic capacitor according to any one of claims 1 to 7, wherein the electrolytic capacitor is an aluminum electrolytic capacitor.