JP7020792B2 - Electrolytic capacitor - Google Patents

Description

The present invention relates to an electrolytic capacitor provided with a hydrogen discharge membrane.

In recent years, electrolytic capacitors such as aluminum electrolytic capacitors have been used in applications such as inverters for wind power generation and solar power generation, and large power sources such as storage batteries.

For example, the anode of an aluminum electrolytic capacitor has an electrochemically formed aluminum oxide film on the surface of an aluminum electrode. When an aluminum electrolytic capacitor is used, if mechanical stress such as excessive stress, vibration, and impact, or electrical stress such as reverse voltage, overvoltage, and overcurrent is applied to the anode, a defective portion is generated in the aluminum oxide film. The aluminum electrolytic capacitor uses an electrolytic solution having excellent film repairability, and an aluminum oxide film is rapidly formed by the reaction between the electrolytic solution and the aluminum of the anode, and the defective portion is repaired. However, at that time, oxidation occurs on the anode side and reduction occurs on the cathode side, and hydrogen gas is generated. When a large amount of defective parts are generated in the aluminum oxide film, a large amount of hydrogen gas is generated due to the film repairing action, and the outer case may expand or explode due to an increase in the internal pressure of the aluminum electrolytic capacitor.

Therefore, a general electrolytic capacitor is provided with a safety valve provided with a special film. In addition to the function of discharging hydrogen gas inside the condenser to the outside, the safety valve has the function of self-destructing and lowering the internal pressure when the internal pressure of the condenser rises sharply to prevent the condenser itself from bursting. be. As the special membrane which is a constituent member of such a safety valve, for example, the following has been proposed.

Patent Document 1 proposes a pressure adjusting film provided with a foil band made of an alloy of palladium silver (Pd-Ag) containing 20 wt% (19.8 mol%) Ag in palladium.

However, the foil strip of Patent Document 1 is liable to become brittle in an environment of about 50 to 60 ° C. or lower, and has a problem that the function as a pressure adjusting film cannot be maintained for a long period of time, and has not been put into practical use.

In order to solve the above problem, Patent Document 2 proposes a hydrogen discharge film containing a Pd-Ag alloy, wherein the content of Ag in the Pd-Ag alloy is 20 mol% or more. .. Further, Patent Document 3 proposes a hydrogen discharge membrane containing a Pd-Cu alloy, wherein the Cu content in the Pd-Cu alloy is 30 mol% or more.

Further, in a general electrolytic capacitor, the film thickness of the oxide film is increased in order to suppress the formation of defective portions in the oxide film. However, since the oxide film is formed electrochemically, increasing the film thickness of the oxide film has a demerit that a large amount of energy and manufacturing time are required. In addition, if the film thickness of the oxide film is increased, the capacitance of the capacitor decreases, so it is necessary to increase the surface area of the oxide film in order to compensate for the decrease in capacitance, which makes it difficult to reduce the size of the electrolytic capacitor. was there.

Japanese Patent No. 4280014 International Publication No. 2014/098038 International Publication No. 2015/01/90906

The present invention has been made in view of the above problems, and there is no risk of the outer case expanding or exploding even when a large amount of hydrogen gas is generated, and the capacitance is large, and the size or withstand voltage is increased. It is an object of the present invention to provide an electrolytic capacitor capable of providing an electrolytic capacitor.

The present invention is an electrolytic capacitor provided with a hydrogen discharge membrane.
The hydrogen discharge film contains a hydrogen gas permeation layer that selectively permeates 99 mol% or more of hydrogen gas when a mixed gas containing equimolar hydrogen gas and nitrogen gas is brought into contact with each other.
The present invention relates to an electrolytic capacitor, 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).

The electrolytic capacitor of the present invention has a ratio (average thickness / rated voltage) of 1.2 to 2.9 (nm / V) between the average thickness of the oxide film of the anode and the rated voltage of the capacitor, and is a conventional electrolytic capacitor. The value of the ratio is smaller than that of the conventional electrolytic capacitor (that is, the average thickness of the oxide film is thinner than that of the conventional electrolytic capacitor).

When the ratio between the average thickness of the oxide film of the anode and the rated voltage of the capacitor is reduced as in the present invention, defects are likely to occur in the oxide film due to mechanical stress or electrical stress, and hydrogen gas is generated by the film repairing action. It occurs in large quantities, and there is a high possibility that the outer case will expand or explode due to an increase in the internal pressure of the electrolytic capacitor. However, the electrolytic capacitor of the present invention includes a hydrogen discharge film including a hydrogen gas permeation layer that selectively permeates 99 mol% or more of hydrogen gas when a mixed gas containing equimolar hydrogen gas and nitrogen gas is brought into contact with each other. Therefore, even if a large amount of hydrogen gas is generated inside the electrolytic capacitor, only the hydrogen gas can be quickly discharged to the outside, and the outer case can be effectively prevented from expanding or exploding.

When the ratio of the average thickness of the oxide film of the anode to the rated voltage of the capacitor is less than 1.2 (nm / V), a large amount of hydrogen gas exceeding the hydrogen discharge capacity of the hydrogen discharge film is generated in a short time. It may occur inside, increasing the risk of expansion or explosion of the outer case, and making 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 capacitance of the electrolytic capacitor, or it becomes difficult to reduce the size of the electrolytic capacitor.

The hydrogen gas permeation layer is preferably a metal layer, and more preferably a Pd alloy layer.

The Pd alloy, which is the material for forming the Pd alloy layer, preferably contains 20 to 65 mol% of Group 11 elements from the viewpoint of excellent hydrogen permeability, oxidation resistance, and embrittlement resistance during hydrogen storage. Further, the Group 11 element is preferably at least one selected from the group consisting of Au, Ag, and Cu, and is preferably Au from the viewpoint of excellent chemical resistance.

The Pd alloy layer containing the Pd-Group 11 elemental alloy dissociates hydrogen molecules into hydrogen atoms on the surface of the film, dissolves the hydrogen atoms in the film, and diffuses the solid-dissolved hydrogen atoms from the high-pressure side to the low-pressure side. It has a function of converting hydrogen atoms into hydrogen molecules again on the surface of the film on the low pressure side and discharging them. When the content of the Group 11 element is less than 20 mol%, the strength of the Pd alloy tends to be insufficient or the above-mentioned function tends to be difficult to be exhibited, and when it exceeds 65 mol%, the hydrogen permeation rate decreases. Tend to do.

The metal layer preferably has a support on one side or both sides. The support is provided to prevent the metal layer from falling into the electrolytic capacitor when it falls off the safety valve or the hydrogen discharge valve. Further, when the metal layer has a function as a safety valve that self-destructs when the internal pressure of the electrolytic capacitor exceeds a predetermined value, when the metal layer is a thin film, the mechanical strength of the metal layer is low. There is a risk of self-destruction before the internal pressure of the electrolytic capacitor reaches a predetermined value, and it cannot function as a safety valve. Therefore, when the metal layer is a thin film, it is preferable to laminate the support on one side or both sides of the metal layer in order to improve the mechanical strength.

Examples of the electrolytic capacitor include an aluminum electrolytic capacitor, a tantalum electrolytic capacitor, and a niobium electrolytic capacitor.

The electrolytic capacitor of the present invention has a thinner average thickness of the oxide film than the conventional electrolytic capacitor. Therefore, the electrolytic capacitor of the present invention has an advantage that the capacitance is large while having the same size as the conventional electrolytic capacitor. Further, the electrolytic capacitor of the present invention has an advantage that it can be downsized or has a high withstand voltage while having the same capacitance as that of the conventional electrolytic capacitor. Further, since 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 the conventional one, and is excellent in terms of cost.

The electrolytic capacitor of the present invention is provided with a hydrogen discharge film capable of stably discharging hydrogen because the hydrogen discharge property does not easily decrease even when used for a long period of time. Further, the hydrogen discharge membrane can not only quickly discharge only the hydrogen gas generated inside the electrolytic capacitor to the outside, but also prevent impurities from entering the inside of the electrolytic capacitor from the outside. Further, the hydrogen discharge membrane may have a function of self-destructing when the internal pressure of the electrolytic capacitor rises sharply to lower the internal pressure and preventing the electrolytic capacitor itself from bursting. Due to these effects, the initial performance of the electrolytic capacitor can be maintained for a long period of time, and the life of the electrolytic capacitor can be extended.

It is a schematic sectional drawing which shows the structure of the hydrogen discharge membrane of this invention. It is a schematic sectional drawing which shows the other structure of the hydrogen discharge membrane of this invention.

Hereinafter, embodiments of the present invention will be described.

The electrolytic capacitor of the present invention includes a hydrogen discharge film, and the hydrogen discharge film selectively permeates 99 mol% or more of hydrogen gas when a mixed gas containing equimolar hydrogen gas and nitrogen gas is brought into contact with each other. Includes a hydrogen gas permeation layer. Further, 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). And.

Examples of the electrolytic capacitor include an aluminum electrolytic capacitor, a tantalum electrolytic capacitor, a niobium electrolytic capacitor, and the like, and an aluminum electrolytic capacitor is particularly preferable. As the constituent members other than the hydrogen discharge membrane and the anode, conventional ones can be used without particular limitation. Further, the electrolytic capacitor of the present invention can be manufactured by a conventional method except that the following hydrogen discharge membrane and anode are used. Hereinafter, the hydrogen discharge membrane and the anode will be described in detail.

The hydrogen discharge film includes a hydrogen gas permeation layer that selectively permeates 99 mol% or more of hydrogen gas when a mixed gas containing equimolar hydrogen gas and nitrogen gas is brought into contact with each other. A hydrogen gas permeable layer that selectively permeates 99.9 mol% or more of hydrogen gas is preferable.

In addition, the hydrogen discharge film has a hydrogen permeation amount of 10 ml / day or more (4.03 × 10 ^-4 mol / day or more) at a pressure square root of 76.81 Pa ^1/2 (0.059 bar): calculated according to SATP (temperature). The volume of 1 mol of the ideal gas at 25 ° C. and 1 bar atm is preferably 24.8 L)). Further, the hydrogen discharge film preferably has a hydrogen permeability coefficient of 1 × 10 ^-12 (mol · m ^-1 · sec ^-1 · Pa-1 / ² ) or more at 50 ° C., more preferably 1 × 10-10. ^-10 (mol ・ m ^-1・ sec ^-1・ Pa-1 / ² ) or more, more preferably 1 × 10 ^-9 (mol ・ m ^-1・ sec ^-1・ Pa-1 / ² ) or more. be.

Examples of the layer having this property include a metal layer such as a Pd alloy layer.

Other metals forming the Pd alloy, which is the material of the Pd alloy layer, are not particularly limited, but for example, Nb, V, Ta, Ni, Fe, Al, Cu, Ru, Re, Rh, Au, Pt, Ag, and the like. Examples thereof include Cr, Co, Sn, Zr, Y, Ce, Ti, Ir, and Mo. One kind of these other metals may be used, or two or more kinds may be used in combination. Of these, it is preferable to use Group 11 elements, and more preferably at least one selected from the group consisting of Au, Ag, and Cu. In particular, the Pd-Au alloy is preferable because it has excellent corrosion resistance to the gas component generated from the electrolytic solution or the constituent members inside the electrolytic capacitor. The Pd alloy preferably contains 20 to 65 mol% of Group 11 elements, more preferably 30 to 65 mol%, and even more preferably 30 to 60 mol%. Further, the Pd alloy layer containing a Pd-Ag alloy having an Ag content of 20 mol% or more, a Pd-Cu alloy having a Cu content of 30 mol% or more, or a Pd-Au alloy having an Au content of 20 mol% or more , Even in a low temperature range of about 50 to 60 ° C. or lower, it is not easily brittled by hydrogen, which is preferable. Further, the Pd alloy may contain Group IB and / or Group IIIA metals as long as the effects of the present invention are not impaired.

The Pd alloy may be not only a two-component alloy containing Pd, but also, for example, a three-component alloy of Pd-Au-Ag or a three-component alloy of Pd-Au-Cu. Further, it may be a four-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. Yes, more preferably 45 mol% or less, and particularly preferably 40 mol% or less.

The Pd alloy layer can be produced by, for example, a rolling method, a sputtering method, a vacuum vapor deposition method, an ion plating method, a plating method, or the like, but when producing a thick Pd alloy layer, a rolling method is used. Is preferable, and when a Pd alloy layer having a thin film thickness is produced, it is preferable to use a sputtering method.

The rolling method may be hot rolling or cold rolling. The rolling method is a method in which a pair or a plurality of pairs of rolls (rollers) are rotated and a metal as a raw material is passed between the rolls while applying pressure to form a film.

The film thickness of the Pd alloy layer obtained by the rolling method is preferably 5 to 50 μm, more preferably 10 to 30 μm. If the film thickness is less than 5 μm, pinholes or cracks are likely to occur during manufacturing, or if hydrogen is occluded, it is likely to be deformed. On the other hand, if the film thickness exceeds 50 μm, it takes time to allow hydrogen to permeate, so that hydrogen permeability is lowered and the cost is inferior, which is not preferable.

The sputtering method is not particularly limited, and can be performed by using a sputtering apparatus such as a parallel plate type, a single-wafer type, a passing type, DC sputtering, and RF sputtering. For example, after mounting the substrate on a sputtering device equipped with a metal target, the inside of the sputtering device is evacuated, the Ar gas pressure is adjusted to a predetermined value, a predetermined sputtering current is applied to the metal target, and Pd is applied on the substrate. Form an alloy film. Then, the Pd alloy film is peeled off from the substrate to obtain a Pd alloy layer. As the target, a single target or a plurality of targets can be used depending on the Pd alloy layer to be manufactured.

Examples of the substrate include glass plates, ceramic plates, silicon wafers, and 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, more preferably 0.05 to 2 μm. If the film thickness is less than 0.01 μm, not only pinholes may be formed, but it is difficult to obtain the required mechanical strength. In addition, it is easily damaged when peeled from the substrate, and handling after peeling becomes difficult. On the other hand, if the film thickness exceeds 5 μm, it takes time to manufacture the Pd alloy layer and it 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 used as a constituent member of the safety valve, it is about 0.01 to 100 mm ² . In the present invention, the film area is the area of the portion of the Pd alloy layer that actually discharges hydrogen, and does not include the portion to which the ring-shaped adhesive described later is applied.

The metal layer preferably has a coat layer on one side or both sides. By providing the coat layer on one side or both sides of the metal layer, pinholes or cracks existing in the metal layer can be closed. As a result, it is possible to prevent the necessary components (electrolyte solution, etc.) inside the electrochemical element from leaking to the outside.

The raw material of the coat layer is not particularly limited, and examples thereof include a fluorine-based compound, a rubber-based polymer, a silicone-based polymer, a urethane-based polymer, and a polyester-based polymer. Of these, 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 of not easily inhibiting the hydrogen permeability of the hydrogen discharge film.

Fluoro-based compounds include, for example, fluoroalkyl group-containing compounds such as fluoroalkyl carboxylates, fluoroalkyl quaternary ammonium salts, and fluoroalkyl ethylene oxide adducts; perfluoroalkyl carboxylates, perfluoroalkyl quaternary ammonium salts, etc. And perfluoroalkyl group-containing compounds such as perfluoroalkylethylene oxide adducts; fluorocarbon group-containing compounds such as tetrafluoroethylene / hexafluoropropylene copolymers and tetrafluoroethylene / perfluoroalkyl vinyl ether copolymers; tetrafluoroethylene polymers; Copolymer of vinylidene fluoride and tetrafluoroethylene; Copolymer of vinylidene fluoride and hexafluoropropylene; Fluorine-containing (meth) acrylic acid ester; Fluorine-containing (meth) acrylic acid ester polymer; Fluorine-containing (meth) acrylic Examples thereof include acid alkyl ester polymers; copolymers of fluorine-containing (meth) acrylic acid esters and other monomers.

In addition, as the fluorine-based compound that is the raw material of the coat layer, the "Durasurf" series manufactured by Harves, the "Optur" series manufactured by Daikin Industries, and the "KY-100" series manufactured by Shin-Etsu Chemical Co., Ltd. are used. You may.

Examples of the rubber-based polymer include natural rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, chloroprene rubber, polyisoprene rubber, polybutadiene rubber, ethylene propylene rubber, ethylene-propylene-diene ternary polymer rubber, and chlorosulphonized polyethylene rubber. And ethylene-vinyl acetate copolymer rubber and the like.

Further, as the rubber-based polymer which is the raw material of the coat layer, the "Elep Coat" series manufactured by Nitto Denko Corporation may be used.

Examples of the silicone-based polymer include polydimethylsiloxane, alkyl-modified polydimethylsiloxane, carboxyl-modified polydimethylsiloxane, amino-modified polydimethylsiloxane, epoxy-modified polydimethylsiloxane, fluorine-modified polydimethylsiloxane, and (meth) acrylate-modified polydimethyl. Examples include siloxane.

The coat layer can be formed, for example, by applying the coat layer raw material composition on the metal layer and curing 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 knife coating method, a die coating method, an inkjet method, and a gravure coating method.

The solvent may be appropriately selected depending on the raw material of the coat layer. When a fluorine-based compound is used as a raw material for the coat layer, for example, a solvent such as a fluorine-based solvent, an alcohol-based solvent, an ether-based solvent, an ester-based solvent, and a hydrocarbon-based solvent can be used alone or in combination. Of these, it is preferable to use a fluorinated solvent that is not flammable and volatilizes quickly, alone or in combination with another solvent.

Examples of the fluorine-based solvent include hydrofluoroether, perfluoropolyether, perfluoroalkane, hydrofluoropolyether, hydrofluorocarbon, perfluorocycloether, perfluorocycloalkane, hydrofluorocycloalkane, xylene hexafluoride, and hydro. Fluorochlorocarbon, perfluorocarbon and the like can be mentioned.

The thickness of the coat layer is not particularly limited, but is preferably 0.1 to 40 μm, more preferably 0.2 to 10 μm, and even more preferably 0.3 to 5 μm.

Supports may 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 preferable to laminate a support on one side or both sides of the Pd alloy layer in order to improve the mechanical strength.

1 and 2 are schematic cross-sectional views showing the structure of the hydrogen discharge film 1. As shown in FIGS. 1A or 1B, the support 4 may be laminated on one side or both sides of the Pd alloy layer 2 using a ring-shaped adhesive 3, and FIGS. 2A or 2B may be used. ) May be used to laminate the support 4 on one side or both sides 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, and may be a non-porous material or a porous body. Further, the support 4 may be a woven fabric or a non-woven fabric. Examples of the material for forming the support 4 include polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyaryl ether sulfone such as polysulfone and polyethersulfone, polytetrafluoroethylene and polyvinylidene fluoride. Fluoro resin, epoxy resin, polyamide, polyimide and the like can be mentioned. Of these, polysulfone or polytetrafluoroethylene, which are chemically and thermally stable, are preferably used.

The support 4 is preferably a porous body having an average pore diameter of 100 μm or less. When the average pore diameter exceeds 100 μm, the surface smoothness of the porous body deteriorates, so that it is difficult to form a Pd alloy layer having a uniform film thickness on the porous body when the Pd alloy layer is produced by a sputtering method or the like. Or, pinholes or cracks are likely to occur in the Pd alloy layer.

The thickness of the support 4 is not particularly limited, but is usually about 5 to 1000 μm, preferably 10 to 300 μm.

When the Pd alloy layer 2 is manufactured by the sputtering method, if the support 4 is used as a substrate, the Pd alloy layer 2 can be directly formed on the support 4, and hydrogen can be formed without using the adhesive 3 or the jig 5. Since the discharge film 1 can be manufactured, it is preferable from the viewpoint of the physical properties of the hydrogen discharge film 1 and the production efficiency. In that 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 in particular, an ultrafiltration membrane (UF membrane) may be used. preferable.

The shape of the hydrogen discharge membrane may be a substantially circular shape, or may be a polygon such as a triangle, a quadrangle, or a pentagon. It can be made into any shape according to the application described later.

The hydrogen discharge membrane is useful as a component of a safety valve of an electrolytic capacitor. Further, the hydrogen discharge membrane can be provided on the electrolytic capacitor as a hydrogen discharge valve separately from the safety valve.

Since the hydrogen discharge membrane does not become embrittled at a low temperature, it has an advantage that it can be used at a temperature of, for example, 150 ° C. or lower, further 110 ° C. or lower. That is, it is suitably used as a safety valve or a hydrogen discharge valve for an electrolytic capacitor that is not used at a high temperature (for example, 400 to 500 ° C.).

The anode used in the electrolytic capacitor of the present invention has a ratio (average thickness / rated voltage) of the average thickness of the oxide film to the rated voltage of the capacitor of 1.2 to 2.9 (nm / V), preferably 1.2 to 2.9 (nm / V). It is 1.3 to 2.4 (nm / V), more preferably 1.4 to 2.0 (nm / V).

For example, in the case of a general aluminum electrolytic capacitor having 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 used in the electrolytic capacitor of the present invention is only 40 to 95% of the average thickness of the conventional oxide film, which is very thin. When an anode having such a very thin oxide film is used as the anode of a conventional electrolytic capacitor, many defects are generated in the oxide film due to mechanical stress or electrical stress, and a large amount of hydrogen gas is generated due to the film repairing action. The outer case expands or bursts due to an increase in the internal pressure of the electrolytic capacitor. However, in the present invention, since the electrolytic capacitor is provided with the hydrogen discharge film, the outer case does not expand or burst even when an anode having such a very thin oxide film is used.

The average thickness of the oxide film can be adjusted to a desired thickness by arbitrarily adjusting the chemical conversion voltage in the chemical conversion step (oxide film forming step).

The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Production Example 1
[Preparation of Pd-Au alloy layer (Au content 30 mol%) by rolling method]
The Pd and Au raw materials were weighed so that the Au content in the ingot was 30 mol%, and the mixture was placed in an arc melting furnace equipped with a water-cooled copper crucible and arc-melted in an atmosphere of Ar gas at atmospheric pressure. The obtained button ingot was cold-rolled to a thickness of 5 mm using a two-stage rolling mill having a roll diameter of 100 mm to obtain a plate material. Then, the rolled plate material was put in the glass tube, and both ends of the glass tube were sealed. The inside of the glass tube was depressurized to 5 × 10 ^-4 Pa at room temperature, then 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 was eliminated. Next, the plate material is cold-rolled to a thickness of 100 μm using a two-stage rolling mill with a roll diameter of 100 mm, and further cold-rolled to a thickness of 20 μm using a two-stage rolling mill with a roll diameter of 20 mm. did. Then, the rolled plate material was put in the glass tube, and both ends of the glass tube were sealed. The inside of the glass tube was depressurized to 5 × 10 ^-4 Pa at room temperature, then heated to 500 ° C. and left for 1 hour, and then cooled to room temperature. By this heat treatment, the strain inside the Pd-Au alloy generated by rolling was removed to prepare a Pd-Au alloy layer having a thickness of 20 μm and an Au content of 30 mol%. Then, a coat layer raw material composition (Durasurf DS-3302TH manufactured by Harves Co., Ltd.) is applied onto the Pd-Au alloy layer by a dip coating method and dried to form a coat layer having a thickness of 0.3 μm and hydrogen. A discharge membrane was prepared.

Manufacturing example 2
[Preparation of Pd-Au alloy layer (Au content 50 mol%) by sputtering method]
An RF magnetron sputtering device (manufactured by Sanyu Electronics Co., Ltd.) equipped with a Pd-Au alloy target having an Au content of 50 mol%, and a polysulfone porous sheet (manufactured by Nitto Denko Co., Ltd., pore diameter 0.001 to 0.02 μm) as a support. ) Was attached. After that, the inside of the sputtering apparatus is evacuated to 1 × 10 ^-5 Pa or less, and a sputtering current of 4.8 A is applied to the Pd—Au alloy target at an Ar gas pressure of 1.0 Pa to thicken the polysulfone porous sheet. A 100 nm Pd—Au alloy layer (Au content 50 mol%) was formed. Then, a coat layer raw material composition (Durasurf DS-3302TH manufactured by Harves Co., Ltd.) is applied onto the Pd-Au alloy layer by a dip coating method and dried to form a coat layer having a thickness of 0.3 μm and hydrogen. A discharge membrane was prepared.

Example 1
[Manufacturing of aluminum electrolytic capacitors]
A 90 μm thick medium- and high-pressure chemical foil (manufactured by Nippon Denki Kogyo Co., Ltd.) with a rating of 200 to 450 V is slit into a square (45 x 45 mm) with a protrusion for drawing out the electrode, and the anode is a thickness of 30 μm. The cathode foil (manufactured by Nippon Kodo Kogyo Co., Ltd.) is slit into a square (45 x 45 mm) with a protrusion for drawing out the electrode, and the cathode is a 70 μm-thick hemp paper (manufactured by Nippon Kodoshi Paper Co., Ltd.). Was slit into a square (50 × 50 mm) slightly larger than the electrode foil to obtain electrolytic paper. Then, the anode and the cathode were overlapped so that the square portions of the electrodes were aligned, and an electrolytic paper was sandwiched between the anode and the cathode to form a capacitor element. At this time, in order to prevent short circuits of the electrodes, the protruding portions of the electrodes were arranged so as not to overlap each other. A nylon resin film with a thickness of 40 μm, an aluminum foil with a thickness of about 50 μm, and a heat-sealing polypropylene resin film with a thickness of 30 μm are laminated in this order on the outer case for accommodating the elements. Two aluminum laminated films (manufactured by Dainippon Printing Co., Ltd.) slit into a square (65 x 130 mm) were used. Here, a φ10 opening was provided in the center of one of the aluminum laminated films, and the φ20 hydrogen discharge film produced in Production Example 1 was attached with an adhesive from the polypropylene resin film surface so as to cover the opening. .. These two aluminum laminated films were laminated so that the polypropylene resin surfaces of the films were overlapped with each other, and the three sides were heat-sealed (200 ° C.) with a width of 10 mm to prepare an outer case. Next, the capacitor element was placed in the outer case from the remaining one side not heat-sealed, and then an ethylene glycol-based electrolytic solution containing ammonium sebacate as a main solute was injected. Then, after injecting the electrolytic solution, the remaining one side not heat-sealed was also heat-sealed with a width of 10 mm to obtain an aluminum electrolytic capacitor.

Example 2
[Manufacturing of aluminum electrolytic capacitors]
In Example 1, an aluminum electrolytic capacitor was obtained by the same method as in Example 1 except that the φ20 hydrogen discharge film produced in Production Example 2 was used instead of the φ20 hydrogen discharge film produced in Production Example 2. ..

Example 3
[Manufacturing of aluminum electrolytic capacitors]
In Example 1, an aluminum electrolytic capacitor was obtained by the same method as in Example 1 except that the sizes of the anode and the cathode were changed to 39 × 39 mm.

Example 4
[Manufacturing of aluminum electrolytic capacitors]
In Example 3, an aluminum electrolytic capacitor was obtained by the same method as in Example 3 except that the φ20 hydrogen discharge film produced in Production Example 2 was used instead of the φ20 hydrogen discharge film produced in Production Example 2. ..

Comparative Example 1
[Manufacturing of aluminum electrolytic capacitors]
In Example 1, an aluminum electrolytic capacitor was obtained by the same method as in Example 1 except that the φ10 opening was not provided in the center of the aluminum laminated film and the φ20 hydrogen discharge film produced in Production Example 1 was not used. rice field.

Comparative Example 2
[Manufacturing of aluminum electrolytic capacitors]
In Example 3, an aluminum electrolytic capacitor was obtained by the same method as in Example 3 except that the φ10 opening was not provided in the central portion of the aluminum laminated film and the φ20 hydrogen discharge film produced in Production Example 1 was not used. rice field.

[Measurement and evaluation method]
(Evaluation of hydrogen permeability)
The prepared hydrogen discharge membrane was attached to a VCR connector manufactured by Swagelok, and a SUS tube was attached to one side to prepare a sealed space (63.5 ml). After depressurizing the inside of the tube with a vacuum pump, the pressure of hydrogen gas was adjusted to 0.15 MPa, and the pressure change in an environment of 105 ° C. was monitored. Since the number of moles of hydrogen (volume) that permeated the hydrogen discharge membrane can be known from the pressure change, the hydrogen permeation amount was calculated by converting this into the permeation amount per day. For example, when the pressure changes from 0.15 MPa to 0.05 MPa in 2 hours (change amount 0.10 MPa), the hydrogen volume permeated through the hydrogen discharge membrane becomes 63.5 ml. Therefore, the amount of hydrogen permeation per day is 63.5 × 24/2 = 762 ml / day. The hydrogen permeation amount of the hydrogen discharge membrane is preferably 10 ml / day or more, and more preferably 100 ml / day or more. The hydrogen permeation amount of the hydrogen discharge membrane of Production Example 1 was 600 ml / day, and the hydrogen permeation amount of the hydrogen discharge membrane of Production Example 2 was 250 ml / day.

(Evaluation of selective permeability of hydrogen gas)
The prepared hydrogen discharge membrane was attached to a VCR connector manufactured by Swagelok, and a SUS tube was attached to one side to prepare a sealed space (63.5 ml). After depressurizing the inside of the tube with a vacuum pump, the pressure of nitrogen gas was adjusted to 150 kPa, and the pressure change in an environment of 105 ° C. was monitored. Since the number of moles of nitrogen (volume) that permeated the hydrogen discharge membrane can be known from the pressure change, the nitrogen permeation amount was calculated by converting this into the permeation amount per day. For example, when the pressure changes from 150 kPa to 149 kPa in 2 hours (change amount 1 kPa), the nitrogen volume permeated through the hydrogen discharge membrane becomes 0.635 ml. Therefore, the amount of nitrogen permeated per day is 0.635 × 24/2 = 7.62 ml / day. The selective permeability of hydrogen gas is expressed by (hydrogen permeation amount-nitrogen permeation amount) ÷ hydrogen permeation amount × 100, and in the above case, (762-7.62) ÷ 762 × 100 = 99%. The nitrogen permeation amount of the hydrogen discharge membrane of Production Example 1 was 0 ml / day, and the nitrogen permeation amount of the hydrogen discharge membrane of Production Example 2 was 0 ml / day. Therefore, the selective permeability of the hydrogen gas of the hydrogen discharge membrane of Production Example 1 is 100%, and the selective permeability of the hydrogen gas of the hydrogen discharge membrane of Production Example 2 is 100%.

(Measurement of capacitance and tan δ, evaluation of appearance change)
The aluminum electrolytic capacitors obtained in Examples 1 to 4 and Comparative Examples 1 and 2 were subjected to a DC voltage of 200 to 600 V for 10 hours using the charge / discharge system controller PFX251S manufactured by Kikusui Electronics Co., Ltd. in an environment of 105 ° C. Continuous application was possible. Then, the capacitance (120 Hz) and tan δ (120 Hz) at 20 ° C. were measured using an LCR meter E4980A manufactured by Keysight Technology Co., Ltd., and the appearance change was observed and evaluated according to the following criteria. The results are shown in Tables 1 and 2.
〇: No change compared to the initial stage.
×: It is swollen compared to the initial stage.

In the aluminum electrolytic capacitors of Examples 1 and 2, there was no change in the outer case even if the value of the oxide film average thickness / rated voltage was reduced. The reason is that the aluminum electrolytic capacitors of Examples 1 and 2 are provided with a special hydrogen discharge film, and the hydrogen gas generated inside the capacitor is quickly discharged to the outside by this hydrogen discharge film, and the internal pressure of the capacitor is increased. It is probable that the rise was effectively suppressed. On the other hand, in the aluminum electrolytic capacitors of Comparative Examples 1 and 2, the outer case expanded when the value of the oxide film average thickness / rated voltage was 2.8 or less. The reason is that the aluminum electrolytic capacitors of Comparative Examples 1 and 2 do not have a special hydrogen discharge film, so that the hydrogen gas generated inside the capacitor cannot be quickly discharged to the outside, and the internal pressure of the capacitor is increased. It is probable that it rose significantly. Further, the aluminum electrolytic capacitor made of the anode foil having the rated voltage of 200V in Examples 1 and 2 has a higher capacitance than the aluminum electrolytic capacitor made of the anode foil having the rated voltage of 250V when a voltage exceeding 200V is applied. It can be seen that by using a special hydrogen discharge film, it is possible to increase the withstand voltage and the capacitance of the aluminum electrolytic capacitor without changing the appearance.

Similar to Examples 1 and 2, in the aluminum electrolytic capacitors of Examples 3 and 4, there was no change in the outer case even if the value of the oxide film average thickness / rated voltage was reduced. The reason is that the aluminum electrolytic capacitors of Examples 3 and 4 are provided with a special hydrogen discharge film, and the hydrogen gas generated inside the capacitor is quickly discharged to the outside by this hydrogen discharge film, and the internal pressure of the capacitor is increased. It is probable that the rise was effectively suppressed. Further, the aluminum electrolytic capacitors made of the anode foils of the rated voltage of 200 V in Examples 3 and 4 are equivalent to the capacitors made of the anode foils of the rated voltage of 250 V of Examples 1 and 2 when a voltage exceeding 200 V is applied. It can be seen that it is possible to reduce the size of the aluminum electrolytic capacitor without changing the appearance by using a special hydrogen discharge film because of the capacitance of.

The electrolytic capacitor of the present invention is suitably used for various power sources and the like.

1: Hydrogen discharge film 2: Pd alloy layer 3: Adhesive 4: Support 5: Jig

Claims (4)

An electrolytic capacitor with a hydrogen discharge membrane
The hydrogen discharge film contains a hydrogen gas permeation layer that selectively permeates 99 mol% or more of hydrogen gas when a mixed gas containing equimolar hydrogen gas and nitrogen gas is brought into contact with each other.
The hydrogen gas permeation layer is a Pd alloy layer containing Au, and is a Pd alloy layer.
An electrolytic capacitor 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). The electrolytic capacitor according to claim 1 , wherein the Pd alloy layer contains 20 to 65 mol% of Au . The electrolytic capacitor according to claim 1 or 2 , wherein the Pd alloy layer has a support on one side or both sides. The electrolytic capacitor according to any one of claims 1 to 3 , wherein the electrolytic capacitor is an aluminum electrolytic capacitor.

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