WO2024029603A1 - Electrolytic capacitor and manufacturing method - Google Patents

Abstract

The present invention provides an electrolytic capacitor using an electrically conductive polymer and having even better capacity, and a manufacturing method. The electrolytic capacitor comprises an electrolyte layer containing the electrically conductive polymer and a plastic crystal. The manufacturing method for this electrolytic capacitor includes an electrolyte layer forming step for forming the electrolyte layer between a pair of electrodes. An electrolyte forming step includes a polymer attachment step for attaching the electrically conductive polymer to one or both of the pair of electrodes, and a plastic crystal attachment step for attaching the plastic crystal to one or both of the pair of electrodes.

Description

Electrolytic capacitor and manufacturing method

The present invention relates to an electrolytic capacitor and a manufacturing method.

Electrolytic capacitors include valve metals such as tantalum or aluminum as anode foils and cathode foils. The anode foil is enlarged by forming the valve metal into a sintered body or etched foil, and has a dielectric oxide film layer on the enlarged surface. An electrolytic solution is interposed between the anode foil and the cathode foil. The electrolyte comes into close contact with the uneven surface of the anode foil and functions as a true cathode.

In recent years, solid electrolytic capacitors using solid electrolytes containing conductive polymers such as polypyrrole, polyaniline, and polythiophene have come into use. Since conductive polymers have high electrical conductivity, they contribute to lower ESR of electrolytic capacitors.

International Publication No. 2007/091656

Compared to a solid electrolyte using a conductive polymer, the electrolytic solution can be brought into close contact with the dielectric oxide film layer of the anode foil, making it easier to increase the capacity of the electrolytic capacitor. Therefore, an electrolytic capacitor using a conductive polymer is also required to have good ESR and good capacitance.

The present invention was proposed in order to solve the above problems, and its purpose is to provide an electrolytic capacitor that uses a conductive polymer and has even better capacity, and a manufacturing method.

In order to solve the above problems, the electrolytic capacitor of this embodiment includes an electrolyte layer containing a conductive polymer and a flexible crystal. It may also include an anode body and a cathode body.

The conductive polymer may include poly(3,4-ethylenedioxythiophene) and polystyrene sulfonic acid.

The flexible crystal may further contain a cation and anion in a different combination from the cation component and anion component of the flexible crystal.

The amount of the flexible crystals may be 2 times or more and 12 times or less in weight ratio when the amount of the conductive polymer is 1.

Further, in order to solve the above problems, the method for manufacturing an electrolytic capacitor of the present embodiment includes an electrolyte layer forming step of forming an electrolyte layer between a pair of electrodes, and the electrolyte forming step includes one or more of the pair of electrodes. The method includes a polymer attachment step of attaching a conductive polymer to both electrodes, and a flexible crystal attachment step of attaching a flexible crystal to one or both of the pair of electrodes.

The polymer adhesion step may include an impregnation step of impregnating a liquid containing the conductive polymer between the pair of electrodes.

In the flexible crystal attachment step, the flexible crystal containing a cation and anion in a different combination from the cation and anion components of the flexible crystal may be attached.

In the flexible crystal attachment step, the amount of the flexible crystals may be deposited at a weight ratio of 2 times or more and 12 times or less when the amount of the conductive polymer is 1.

According to the present invention, better capacity can be obtained compared to the case where a conductive polymer is used.

Hereinafter, modes for carrying out the present invention will be described. Note that the present invention is not limited to the embodiments described below.

(overall structure)
An electrolytic capacitor is a passive element that obtains capacitance through the dielectric polarization effect of a dielectric oxide film and stores and discharges charge. An electrolytic capacitor includes a pair of electrodes and an electrolyte layer sandwiched between the electrodes. One electrode is an anode body, and a dielectric oxide film is formed on the surface. The other electrode is the cathode body. The electrolyte layer contains a conductive polymer and flexible crystals.

The conductive polymer is a self-doped conjugated polymer doped with an intramolecular dopant molecule, or a conjugated polymer doped with an external dopant molecule. Conjugated polymers are obtained by chemical oxidative polymerization or electrolytic oxidative polymerization of monomers having π-conjugated double bonds or derivatives thereof. The dopant or external dopant molecule is an acceptor that easily accepts electrons or a donor that easily donates electrons to the conjugated polymer, and thereby the conductive polymer exhibits high electrical conductivity.

A plastic crystal is also called a plastic crystal, and has an ordered arrangement and a disordered orientation. That is, while a flexible crystal has a three-dimensional crystal lattice structure in which anions and cations are regularly arranged, these anions and cations have rotational irregularity.

An electrolyte layer containing these conductive polymers and flexible crystals is interposed between the anode body and the cathode body. In other words, the anode body and the cathode body are arranged to face each other with the electrolyte layer in between. The electrolyte layer is placed in close contact with the dielectric oxide film of the anode body, so as to be continuous between the dielectric oxide film and the cathode body, thereby creating a conductive path and functioning as a true cathode.

The anode body and the cathode body are arranged in a laminated type in which they are alternately laminated with an electrolyte layer in between, or in a wound type in which they are alternately laminated and wound with an electrolyte layer in between. In the laminated type, the capacitor element is not only a flat plate type without an exterior packaging, but also is sealed by covering the capacitor element with a laminate film, or by molding, dip coating, or printing a resin such as a heat-resistant resin or an insulating resin.

Alternatively, the anode body and the cathode body are arranged in a winding manner in which they are alternately laminated and wound with an electrolyte layer in between. In the winding type, for example, the capacitor element is inserted into a bottomed cylindrical outer case, and the open end of the outer case is sealed with a sealing body by crimping. The sealing body is made of, for example, rubber or a laminate of rubber and a hard substrate. Examples of the rubber include ethylene propylene rubber and butyl rubber.

In addition, a separator is provided between the anode body and the cathode body to separate the anode body and the cathode body and to hold an electrolyte layer between the anode body and the cathode body in order to prevent short circuit between the anode body and the cathode body. It will be done. If the shape of the electrolyte layer is maintained by itself and the electrolyte layer can separate the cathode and anode bodies, the separator can be eliminated from the electrolytic capacitor.

(Anode body)
In such an electrolytic capacitor, the anode body is a foil body made of a valve metal. A wound type electrolytic capacitor has a long band shape made of stretched valve metal, and a laminated type electrolytic capacitor has a flat plate or a sintered body made of powder molded into a flat plate shape and sintered. Valve metals include aluminum, tantalum, niobium, niobium oxide, titanium, hafnium, zirconium, zinc, tungsten, bismuth, and antimony. The purity of the anode body is preferably 99.9% or more, but it may contain impurities such as silicon, iron, copper, magnesium, and zinc.

A surface expanding layer is formed on one or both sides of the anode body. The surface expanding layer is an etched layer obtained by etching a foil, a sintered layer obtained by sintering valve metal powder, or a vapor deposition layer obtained by vapor depositing valve metal particles onto a foil. That is, the surface-expanding layer has a porous structure, consisting of tunnel-like pits, cavernous pits, or dense powder or voids between particles.

A tunnel-shaped etching pit is a hole dug in the thickness direction of the foil. This tunnel-shaped etching pit is typically formed by passing a direct current in an acidic aqueous solution containing halogen ions, such as hydrochloric acid. The diameter of the tunnel-shaped etching pit is further expanded by passing a direct current in an acidic aqueous solution such as nitric acid. Due to the spongy etching pits, the surface-expanding layer becomes a spongy layer in which fine voids are arranged in a series of spaces. These cavernous etching pits are formed by passing an alternating current in an acidic aqueous solution containing halogen ions, such as hydrochloric acid.

The sintered layer is obtained by pulverizing, atomizing, melt spinning, rotating disk method, rotating electrode method, etc. powder of valve metal of the same type or different type as the foil body, making it into a paste with a binder or solvent, and applying it to the foil body. It is produced by coating, drying, and heating and sintering in a vacuum or reducing atmosphere. The atomization method may be a water atomization method, a gas atomization method, or a water gas atomization method. The vapor deposition layer is produced, for example, by a resistance heating vapor deposition method or an electron beam heating vapor deposition method. This vapor deposition layer is formed by heating and vaporizing a valve metal of the same type or different type as the foil body using resistance heat or electron beam energy, and depositing vapor of valve metal particles on the surface of the foil body.

The dielectric oxide film is formed on one or both sides of the anode body on which the surface-expanding layer is formed. The dielectric oxide film is typically an oxide film formed on the surface layer of the anode body, and if the anode body is made of aluminum, it is an aluminum oxide layer obtained by oxidizing the surface of the surface expanding layer. In chemical conversion treatment to form a dielectric oxide film, a voltage is applied to the anode body in a chemical solution to achieve a desired withstand voltage. The chemical solution is a solution that does not have halogen ions, and includes, for example, a phosphoric acid-based chemical solution such as ammonium dihydrogen phosphate, a boric acid-based chemical solution such as ammonium borate, and an adipic acid-based chemical solution such as ammonium adipate. It is a liquid.

An anode lead is connected to this anode body and drawn out of the capacitor element. A capacitor element is an assembly of an anode body, a cathode body, an electrolyte layer and a separator. The anode lead is connected to the anode body by stitching, cold welding, ultrasonic welding, laser welding, or the like.

(Cathode body)
In the case of a wound type electrolytic capacitor, the cathode body is preferably a stretched foil made of valve metal. The purity of the cathode body is preferably 99% or more. A surface expanding layer is formed on the cathode body as well as on the anode body. A plain foil without a surface expanding layer may be used as the cathode body. The cathode body may have a natural oxide film or a thin oxide film (approximately 1 to 10 V) formed by chemical conversion treatment. A natural oxide film is formed when the cathode reacts with oxygen in the air. Further, a layer made of metal nitride, metal carbide, or metal carbonitride may be formed on the cathode body by a vapor deposition method, or a layer containing carbon may be formed on the surface.

Alternatively, in the case of a multilayer electrolytic capacitor, the cathode body is preferably a laminate of a metal layer and a carbon layer. The carbon layer of the cathode body is arranged toward the anode body. The carbon layer is formed by forming the paste into a paste, forming an electrolyte layer on the anode body, then coating the paste on the electrolyte layer, and curing by heating. The metal layer is, for example, a silver layer, and the metal layer is formed by making it into a paste, coating it on top of the carbon layer, and curing it by heating.

A cathode lead is connected to this cathode body and drawn out to the outside of the capacitor element. The cathode lead is connected to the cathode body by stitching, cold welding, ultrasonic welding, laser welding, or the like.

(electrolyte layer)
(conductive polymer)
As the conjugated polymer, known ones can be used without particular limitation. Examples include polypyrrole, polythiophene, polyfuran, polyaniline, polyacetylene, polyphenylene, polyphenylene vinylene, polyacene, polythiophene vinylene, and the like. These conjugated polymers may be used alone, two or more types may be used in combination, or a copolymer of two or more types of monomers may be used.

Among the above conjugated polymers, conjugated polymers formed by polymerizing thiophene or its derivatives are preferred, and 3,4-ethylenedioxythiophene (i.e., 2,3-dihydrothieno[3,4-b][1 , 4] dioxine), 3-alkylthiophene, 3-alkoxythiophene, 3-alkyl-4-alkoxythiophene, 3,4-alkylthiophene, 3,4-alkoxythiophene, or a conjugated polymer in which a derivative thereof is polymerized. is preferred. The thiophene derivative is preferably a compound selected from thiophenes having substituents at the 3- and 4-positions, and the substituents at the 3- and 4-positions of the thiophene ring form a ring together with the carbon atoms at the 3- and 4-positions. It's okay. Suitably, the alkyl group or alkoxy group has 1 to 16 carbon atoms.

Particularly preferred is a polymer of 3,4-ethylenedioxythiophene called EDOT, ie, poly(3,4-ethylenedioxythiophene) called PEDOT. Furthermore, a substituent may be added to 3,4-ethylenedioxythiophene. For example, alkylated ethylenedioxythiophene to which an alkyl group having 1 to 5 carbon atoms is added as a substituent may be used. Examples of the alkylated ethylenedioxythiophene include methylated ethylenedioxythiophene (i.e., 2-methyl-2,3-dihydro-thieno[3,4-b][1,4]dioxin), ethylated ethylenedioxythiophene, oxythiophene (i.e., 2-ethyl-2,3-dihydro-thieno[3,4-b][1,4]dioxin), butylated ethylenedioxythiophene (i.e., 2-butyl-2,3-dihydro- Examples include thieno[3,4-b][1,4]dioxin), 2-alkyl-3,4-ethylenedioxythiophene, and the like.

As the dopant, any known dopant can be used without particular limitation. Dopants may be used alone or in combination of two or more. Further, polymers or monomers may be used. For example, dopants include polyanions, inorganic acids such as boric acid, nitric acid, phosphoric acid, acetic acid, oxalic acid, citric acid, tartaric acid, squaric acid, rhodizonic acid, croconic acid, salicylic acid, p-toluenesulfonic acid, 1,2 -dihydroxy-3,5-benzenedisulfonic acid, methanesulfonic acid, trifluoromethanesulfonic acid, borodisalicylic acid, bisoxalate borate acid, sulfonylimidic acid, dodecylbenzenesulfonic acid, propylnaphthalenesulfonic acid, butylnaphthalenesulfonic acid, etc. Examples include organic acids.

The polyanion is, for example, a substituted or unsubstituted polyalkylene, a substituted or unsubstituted polyalkenylene, a substituted or unsubstituted polyimide, a substituted or unsubstituted polyamide, a substituted or unsubstituted polyester, and has an anion group. Examples include polymers consisting only of units, and polymers consisting of constitutional units having an anionic group and constitutional units not having anionic groups. Specifically, polyanions include polyvinylsulfonic acid, polystyrenesulfonic acid, polyallylsulfonic acid, polyacrylsulfonic acid, polymethacrylsulfonic acid, poly(2-acrylamido-2-methylpropanesulfonic acid), and polyisoprenesulfonic acid. , polyacrylic acid, polymethacrylic acid, polymaleic acid, and the like.

This conductive polymer is produced by chemical oxidative polymerization or electrolytic oxidative polymerization. In chemical oxidative polymerization, a solution containing a monomer that becomes a monomer unit of a conductive polymer is mixed with an oxidizing agent and subjected to a polymerization reaction. The oxidizing agent may be any known compound that releases a dopant, including trivalent iron such as iron(III) p-toluenesulfonate, iron(III) naphthalenesulfonate, and iron(III) anthraquinonesulfonate. Salts or peroxodisulfates such as peroxodisulfate, ammonium peroxodisulfate, sodium peroxodisulfate, etc. can be used, and a single compound may be used, or two or more types of compounds may be used. Good too. There is no strict limit to the polymerization temperature, but it is generally in the range of 10 to 200°C. Polymerization time generally ranges from 10 minutes to 30 hours.

In electrolytic oxidation polymerization, a monomer that becomes a monomer unit of a conductive polymer and a supporting electrolyte are mixed and subjected to a polymerization reaction using a constant potential method, a constant current method, or a potential sweep method. The supporting electrolyte includes at least one compound selected from the group consisting of borodisalicylic acid and borodisalicylate. Examples of salts include alkali metal salts such as lithium salts, sodium salts, and potassium salts; alkylammonium salts such as ammonium salts, ethylammonium salts, and butylammonium salts; dialkylammonium salts such as diethylammonium salts and dibutylammonium salts; and triethylammonium salts. , trialkylammonium salts such as tributylammonium salts, and tetraalkylammonium salts such as tetraethylammonium salts and tetrabutylammonium salts.

When using the constant potential method, a potential of 1.0 to 1.5 V with respect to the reference electrode is suitable; when using the constant current method, a current value of 1 to 10,000 μA/cm ² is suitable; When using the sweep method, it is preferable to sweep the range of 0 to 1.5 V with respect to the reference electrode at a rate of 5 to 200 mV/sec. There is no strict limit to the polymerization temperature, but it is generally in the range of 10 to 60°C. Polymerization time generally ranges from 10 minutes to 30 hours.

In chemical oxidative polymerization or electrolytic oxidative polymerization, the solvent to which the monomer and oxidizing agent or supporting electrolyte are added may be any solvent that can dissolve the desired amount of monomer and supporting electrolyte and does not have a negative effect on the electrolytic oxidative polymerization. can do. For example, the solvent includes water, methanol, ethanol, isopropanol, butanol, ethylene glycol, acetonitrile, butyronitrile, acetone, methyl ethyl ketone, tetrahydrofuran, 1,4-dioxane, γ-butyrolactone, methyl acetate, ethyl acetate, methyl benzoate, benzoate. Examples include ethyl acid, ethylene carbonate, propylene carbonate, nitromethane, nitrobenzene, sulfolane, and dimethylsulfolane. These solvents may be used alone or in combination of two or more.

Conductive polymers are produced by immersing the object to which the conductive polymer is attached into a solution of a monomer that becomes the monomer unit of the conductive polymer and an oxidizing agent or a supporting electrolyte, and then producing it through a polymerization reaction. , formed within an electrolytic capacitor. The object to be adhered includes at least the anode body. In addition to the anode body, one or both of the cathode body and the separator may be objects to which conductive polymers are attached. In addition, a capacitor element, which is an assembly including an anode body, a cathode body, and a separator, is immersed in a solution of a monomer that becomes a monomer unit of a conductive polymer and an oxidizing agent or a supporting electrolyte, and then polymerized. You may react.

Further, the conductive polymer may be formed in the electrolytic capacitor by using an impregnation method in which the object to be attached is impregnated with a conductive polymer liquid in which conductive polymer particles or powder are dispersed or dissolved. Conductive polymer liquid is obtained by purifying the solution after chemical oxidation polymerization or electrolytic oxidation polymerization by ultrafiltration, cation exchange, anion exchange, etc. to remove residual monomers and impurities, and then dispersing it in the solution. It is prepared in

The solvent for the conductive polymer liquid only needs to disperse or dissolve the conductive polymer, and is preferably water or a mixture of water and an organic solvent. Examples of the organic solvent include polar solvents, alcohols, esters, hydrocarbons, carbonate compounds, ether compounds, chain ethers, heterocyclic compounds, and nitrile compounds.

Examples of the polar solvent include N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, and the like. Examples of alcohols include methanol, ethanol, propanol, butanol, and the like. Examples of esters include ethyl acetate, propyl acetate, butyl acetate, and the like. Examples of hydrocarbons include hexane, heptane, benzene, toluene, xylene, and the like. Examples of carbonate compounds include ethylene carbonate and propylene carbonate. Examples of the ether compound include dioxane and diethyl ether. Examples of chain ethers include ethylene glycol dialkyl ether, propylene glycol dialkyl ether, polyethylene glycol dialkyl ether, and polypropylene glycol dialkyl ether. Examples of the heterocyclic compound include 3-methyl-2-oxazolidinone and the like. Examples of the nitrile compound include acetonitrile, glutarodinitrile, methoxyacetonitrile, propionitrile, benzonitrile, and the like.

The pH of the conductive polymer liquid may be adjusted, and polyhydric alcohol and various additives may be added as necessary. Examples of the pH adjuster include aqueous ammonia. Examples of polyhydric alcohols include sorbitol, ethylene glycol, diethylene glycol, triethylene glycol, polyoxyethylene glycol, glycerin, polyoxyethylene glycerin, xylitol, erythritol, mannitol, dipentaerythritol, pentaerythritol, or a combination of two or more of these. can be mentioned. Since polyhydric alcohol has a high boiling point, it remains in the electrolyte layer even after the object to be adhered is impregnated with the conductive polymer liquid and dried, thereby reducing the ESR and improving the withstand voltage of the electrolytic capacitor. Examples of additives include organic binders, surfactants, dispersants, antifoaming agents, coupling agents, antioxidants, and ultraviolet absorbers.

After impregnating the object with the conductive polymer liquid, the solvent is removed through a drying process. The temperature environment in the drying step is, for example, 40° C. or more and 200° C. or less, and the drying time is, for example, in the range of 3 minutes or more and 180 minutes or less. The drying step may be repeated multiple times. It may be dried in a reduced pressure environment, for example, the pressure is reduced from 5 kPa to 100 kPa. The drying process may be divided into a preliminary drying process and a main drying process. In addition to dipping, a conductive polymer solution may be applied by dropping or spraying.

(flexible crystal)
The types of anion component and cation component constituting the flexible crystal are not particularly limited as long as they are in a solid state rather than an ionic liquid within the target temperature range in which the electrolytic capacitor is used.

The anion components constituting the flexible crystal include various amide anions, tris (trifluoromethanesulfonyl) methanide anions, various phosphate anions, various borate anions, various sulfone anions, tetrafluoroaluminate anions, mandelate anions, and benzoates. Examples include anions.

In various amide anions, two hydrogen atoms of the NH ₂ anion are substituted with a perfluoroalkylsulfonyl group, a fluorosulfonyl group, or both. Various amide anions include, for example, linear ones, such as various bis(perfluoroalkylsulfonyl)amide anions, bis(fluorosulfonyl)amide anions, and various N-(fluorosulfonyl) represented by the following chemical formula (1). -N-(perfluoroalkylsulfonyl)amide anion is included.

　化学式（１）の式中、ｎ及びｍは０以上の整数であり、炭素数は何れでもよい。 (Chem.1)

In the chemical formula (1), n and m are integers of 0 or more, and the number of carbon atoms may be any number.

In the chemical formula (1), if n and m are 1 or more, it is a bis(perfluoroalkylsulfonyl)amide anion. Specifically, the bis(perfluoroalkylsulfonyl)amide anion includes bis(trifluoromethanesulfonyl)amide anion (TFSA anion) represented by the following chemical formula (2), and bis(pentafluorocarbonyl)amide anion represented by the following chemical formula (3). fluoroethylsulfonyl)amide anion (BETA anion).

(Case 2)

(Case 3)

In addition, the bis(perfluoroalkylsulfonyl)amide anion is specifically, in the chemical formula (1), n is 1 and m is 2, and is represented by the following chemical formula (4) (pentafluoroethyl sulfonyl) trifluoromethanesulfonylamide anion.

(Case 4)

In the chemical formula (1), a group having 0 carbon atoms is a fluorosulfonyl group, and if n and m are 0, a bis(fluorosulfonyl)amide anion (FSA anion) represented by the following chemical formula (5) is used. ).

(C5)

In the chemical formula (1), if n is 0 and m is 1 or more, it is an N-(fluorosulfonyl)-N-(perfluoroalkylsulfonyl)amide anion represented by the following chemical formula (6). . Specifically, the N-(fluorosulfonyl)-N-(perfluoroalkylsulfonyl)amide anion is represented by the following chemical formula (7), where m is 1, and N-(fluorosulfonyl)-N-(trifluoromethane). N-(fluorosulfonyl)-N-(pentafluoroethylsulfonyl)amide anion where m is 2 and is represented by the following chemical formula (8).

(C6)

(Chem.7)

(Chem.8)

　化学式（９）の式中、ｎは０以上の整数であり、炭素数は何れでもよい。 In addition, various amide anions include (perfluoroalkylsulfonyl) fluoroacetamide anions, which are represented by the following chemical formula (9) and have two hydrogen atoms of the NH ₂ anion substituted with a perfluoroalkylsulfonyl group and a fluoroacetyl group. It will be done.
(C9)

In the chemical formula (9), n is an integer of 0 or more, and the number of carbon atoms may be any number.

Various amide anions include, for example, five-membered and six-membered heterocyclic rings, and are represented by the following chemical formula (10): N,N-hexafluoro-1,3-disulfonyl amide anion (CFSA). anion), and N,N-pentafluoro-1,3-disulfonylamide anion represented by the following chemical formula (11).

(Chem.10)

(Chem.11)

Tris(trifluoromethanesulfonyl) methanide anion (TFSM anion) is represented by the following chemical formula (12).
(Chem.12)

Various phosphate anions are hexafluorophosphate anions (PF ₆ anions) represented by the following chemical formula (13), or represented by the following chemical formula (14), in which some fluorine atoms of PF ₆ are substituted with fluoroalkyl groups. Various perfluoroalkyl phosphate anions.

(Chem.13)

化学式（１４）の式中、ｑは１以上の整数であり、炭素数は何れでもよい。 (Chem.14)

In the chemical formula (14), q is an integer of 1 or more, and the number of carbon atoms may be any number.

Specifically, tris(pentafluoroethyl)trifluorophosphate anion (FAP anion) represented by the following chemical formula (15) can be mentioned.
(Chem.15)

Various borate anions include a tetrafluoroborate anion (BF ₄ anion) represented by the following chemical formula (16), and a tetrafluoroborate anion (BF 4 anion) represented by the following chemical formula (17), in which some fluorine atoms of the BF ₄ anion are substituted with fluoroalkyl groups. Various perfluoroalkyl borate anions can be mentioned. Specific examples of the various perfluoroalkylborate anions include mono(fluoroalkyl)trifluoroborate anions and bis(fluoroalkyl)fluoroborate anions.

(Chem.16)

　式中、ｓは０以上の整数、ｔは１以上の整数であり、炭素数は何れでもよい。 (Chem.17)

In the formula, s is an integer of 0 or more, t is an integer of 1 or more, and the number of carbon atoms may be any number.

式中、Ｒ１及びＲ２は、それぞれ独立してケトン基又はベンジル位の水素が一つ脱離したベンジル基であり、またはＲ１とＲ２が共通の芳香族六員環の炭素原子である。式中、Ｒ３及びＲ４は、それぞれ独立してケトン基又はベンジル位の水素が一つ脱離したベンジル基であり、またはＲ３とＲ４が共通の芳香族六員環を構成する炭素原子である。 Further, various borate anions include borate anions represented by the following chemical formula (18).
(Chem.18)

In the formula, R1 and R2 are each independently a ketone group or a benzyl group from which one hydrogen at the benzyl position has been removed, or R1 and R2 are carbon atoms of a common six-membered aromatic ring. In the formula, R3 and R4 are each independently a ketone group or a benzyl group from which one hydrogen at the benzyl position has been removed, or R3 and R4 are carbon atoms constituting a common six-membered aromatic ring.

In the chemical formula (18), if R1, R2, R3 and R4 are all ketone groups, it is a bis(oxalato)borate anion (BoB anion) represented by the following chemical formula (18A).
(Chem.18A)

In addition, in the chemical formula (18), if R1 and R2 are carbon atoms constituting a common six-membered aromatic ring, and R3 and R4 are carbon atoms constituting a common six-membered aromatic ring, then the following It is a bis(pyrocatecholato)borate anion represented by the chemical formula (18B).
(Chem.18B)

In addition, in the chemical formula (18), if R1 and R4 are benzyl groups with one hydrogen removed at the benzyl position, and R2 and R3 are ketone groups, bis( Mandelato) is a borate anion.
(Chemical 18C)

式中、Ｒ１～Ｒ６は、それぞれ独立してケトン基又はメチレン基である。または、式中、Ｒ１又はＲ３の何れかがケトン基又はメチレン基であり、他のＲ１及びＲ２の組み合わせ又はＲ２及びＲ３の組み合わせが共通の芳香族六員環の炭素原子である。そして、式中、Ｒ４又はＲ６の何れかがケトン基又はメチレン基であり、他のＲ４及びＲ５の組み合わせ又はＲ５及びＲ６の組み合わせが共通の芳香族六員環の炭素原子である。芳香族六員環は１つ又は４つのメチル基を有していてもよく、また芳香族六員環は、ナフタレン環のような、２つ以上の芳香族環を有する多環式芳香族環の一部である。 Further, various borate anions include borate anions represented by the following chemical formula (19).
(Chem.19)

In the formula, R1 to R6 are each independently a ketone group or a methylene group. Alternatively, in the formula, either R1 or R3 is a ketone group or a methylene group, and the other combinations of R1 and R2 or the combinations of R2 and R3 are carbon atoms of a common six-membered aromatic ring. In the formula, either R4 or R6 is a ketone group or a methylene group, and the other combinations of R4 and R5 or the combinations of R5 and R6 are carbon atoms of a common six-membered aromatic ring. A six-membered aromatic ring may have one or four methyl groups, and a six-membered aromatic ring can also be a polycyclic aromatic ring having two or more aromatic rings, such as a naphthalene ring. is part of.

In the chemical formula (19), R1 and R6 are ketone groups, R2 and R3 are carbon atoms that constitute a common six-membered aromatic ring, and R4 and R5 constitute a common six-membered aromatic ring. If it is a carbon atom, it is a bis(salicylate)borate anion (BScB anion) represented by the following chemical formula (19A).
(Chem.19A)

In the chemical formula (19), R1 and R6 are ketone groups, R2 and R3 are carbon atoms that constitute a common six-membered aromatic ring, and R4 and R5 constitute a common six-membered aromatic ring. When it is a carbon atom and both aromatic six-membered rings each have four methyl groups, it is a bis(tetramethylsalicylate)borate anion represented by the following chemical formula (19B).
(Chem.19B)

In the chemical formula (19), R1 and R6 are ketone groups, R2 and R3 are carbon atoms that constitute a common six-membered aromatic ring, and R4 and R5 constitute a common six-membered aromatic ring. When it is a carbon atom and both aromatic six-membered rings each have one methyl group, it is a bis(methylsalicylate)borate anion (BmScB anion) represented by the following chemical formula (19C).
(Chemical formula 19C)

In the chemical formula (19), when R1 and R6 are ketone groups, R2 and R3 are carbon atoms constituting a common naphthalene ring, and R4 and R5 are carbon atoms constituting a common naphthalene ring, Bis(1-hydroxy-2-naphthorato)borate anion represented by the following chemical formula (20A), bis(2-hydroxy-1-naphthorato)borate anion (BhNB anion) represented by the following chemical formula (20B), or the following It is a bis(3-hydroxy-2-naphthorato)borate anion represented by the chemical formula (20C).

(Case 20A)

(Case 20B)

(Chemical 20C)

Examples of various sulfonic anions include alkylsulfonic acid anions represented by the following chemical formula (21) and various perfluoroalkylsulfonic acid anions represented by the following chemical formula (22).

　化学式（２１）の式中、ｘは１以上４以下の整数である。 (Case 21)

In the chemical formula (21), x is an integer of 1 or more and 4 or less.

　化学式（２２）の式中、ｙは１以上４以下の整数である。 (Chem.22)

In the chemical formula (22), y is an integer of 1 or more and 4 or less.

Specifically, various perfluoroalkylsulfonic acid anions include trifluoromethanesulfonic acid anions in which y is 1 in the above chemical formula (22), pentafluoroethyl sulfonic acid anions in which y is 2 in the above chemical formula (22), and the above. Examples include a heptafluoropropanesulfonic acid anion in which y is 3 in the chemical formula (22), and a nonafluorobutanesulfonic acid anion in which y is 4 in the chemical formula (22).

The tetrafluoroaluminate anion is represented by the following formula (23).
(Case 23)

Mandelate anion is represented by the following formula (24).
(Case 24)

The benzoate anion is represented by the following formula (25).
(Chem.25)

Examples of the cation component constituting the flexible crystal include various quaternary ammonium cations, various pyrrolidinium cations, various piperidinium cations, various imidazolium cations, and various phosphonium cations.

　式中、ａ、ｂ、ｃ及びｄは１以上の整数であり、炭素数は何れでもよい。 Examples of the quaternary ammonium cation include a tetraalkylammonium cation represented by the following chemical formula (26) and substituted with a linear alkyl group having any number of carbon atoms.
(Case 26)

In the formula, a, b, c and d are integers of 1 or more, and the number of carbon atoms may be any.

In the above chemical formula (26), when a, b, c and d are 2, it is a tetraethylammonium cation (TEA cation) represented by the following chemical formula (27).
(Case 27)

In the above chemical formula (26), when a, b and c are 2 and d is 1, the triethylmethylammonium cation (TEMA cation) is represented by the following chemical formula (28).
(C28)

　式中、Ｒ１及びＲ２は、メチル基、エチル基又はイソプロピル基。 Furthermore, examples of the quaternary ammonium cation include a five-membered ring pyrrolidinium cation represented by the following chemical formula (29) to which a methyl group, ethyl group, or isopropyl group is bonded.
(Chem.29)

In the formula, R1 and R2 are a methyl group, an ethyl group or an isopropyl group.

Specific examples of the generalized five-membered pyrrolidinium cation represented by the above chemical formula (29) include, for example, N-ethyl-N-methylpyrrolidinium cation (P12 cation) represented by the following chemical formula (30). , N-isopropyl-N-methylpyrrolidinium cation (P13iso cation) represented by the following chemical formula (31), and N,N-diethylpyrrolidinium cation (P22 cation) represented by the following chemical formula (32). It will be done.

(C30)

(Chem.31)

(C32)

Furthermore, examples of quaternary ammonium include spiro-type pyrrolidinium cations (SBP cations) represented by the following chemical formula (33).
(Chem.33)

　式中、Ｒ３及びＲ４は、メチル基、エチル基又はイソプロピル基。 Various piperidinium cations are represented by the following chemical formula (34), and include piperidinium cations in which the methyl group, ethyl group, or isopropyl group is a six-membered ring.
(Chem.34)

In the formula, R3 and R4 are a methyl group, an ethyl group, or an isopropyl group.

As a specific example of the six-membered piperidinium cation generalized by the above chemical formula (34), for example, 1-ethyl- Examples include 1-methylpiperidinium cation.
(Chem.35)

　式中、ｈとｉは１以上３以下の整数、ｊは０又は１ Various imidazolium cations are 1,3-dialkylimidazolium or 1,2,3-trialkylimidazolium cations represented by the following chemical formula (36).
(C36)

In the formula, h and i are integers from 1 to 3, and j is 0 or 1.

In the chemical formula (36), when j is 0, h and i are 1, it is a 1,3-dimethylimidazolium cation (DMI cation) represented by the following chemical formula (37). The 2-position of this DMI cation may be substituted with a methyl group.
(C37)

In the chemical formula (36), when j is 0, h is 1 and i is 2, it is a 1-ethyl-3-methylimidazolium cation (EMI cation) represented by the following chemical formula (38). The 2-position of this EMI cation may be substituted with a methyl group.
(C38)

In the chemical formula (36), when j is 0, h is 1 and i is 3, it is a 1-methyl-3-propylimidazolium cation (MPI cation) represented by the following chemical formula (39). The 2-position of this MPI cation may be substituted with a methyl group.
(Chem.39)

　式中、ｅ、ｆ、ｇ及びｈは１以上の整数であり、炭素数は何れでもよい。 Various phosphonium cations are represented by the following chemical formula (40), and include tetraalkylphosphonium cations substituted with a linear alkyl group having any number of carbon atoms. Examples of the tetraalkylphosphonium cation include tetraethylphosphonium cation (TEP cation).
(C40)

In the formula, e, f, g and h are integers of 1 or more, and the number of carbon atoms may be any.

Two or more types of such flexible crystals may be included in the electrolyte layer. When two or more types of anion components capable of forming a flexible crystal are used as a mixture in an electrolyte layer, the ionic conductivity of the electrolyte layer is improved compared to a case where a single type of anion component is used. Furthermore, when two or more types of cationic components capable of forming a flexible crystal are mixed and used in an electrolyte layer, the ionic conductivity of the electrolyte layer is improved compared to a case where a single type of cationic component is used.

When two or more types of flexible crystals are included, flexible crystals of the same type of anion may be included in the electrolyte layer, flexible crystals of the same type of cation may be included in the electrolyte layer, or flexible crystals of the same type of anion may be included in the electrolyte layer. Flexible crystals having different components and cationic components may be included in the electrolyte layer. The blending ratios of different flexible crystals in the electrolyte layer may be equal molar amounts or may be different amounts.

Furthermore, the flexible crystal may contain a combination of cations and anions that is different from the cation component and anion component of the flexible crystal. The cations and anions contained in the flexible crystals only need to be ionically dissociated within the operating temperature range of the electrolytic capacitor. Such cations and anions may be contained in the flexible crystal, for example, as an ionic liquid. An ionic liquid is a salt that exists in a liquid state in a temperature range including room temperature, and is a liquid consisting only of ions.

The cation contained in the flexible crystal may be of the same type as the cation component constituting the flexible crystal, as long as the anion contained in the flexible crystal is different. The anion contained in the flexible crystal may be of the same type as the anion component constituting the flexible crystal, as long as the cation contained in the flexible crystal is different. The cation contained in the flexible crystal and the cation component constituting the flexible crystal are different types, and furthermore, the anion contained in the flexible crystal and the anion component forming the flexible crystal may be different types. .

Such anions include various amide anions of the above chemical formulas (1) to (25), tris(trifluoromethanesulfonyl)methanide anions, various phosphate anions, various borate anions, various sulfonic anions, tetrafluoroaluminate anions, Mendelate anions and benzoate anions are mentioned. Examples of the cation include various quaternary ammonium cations, various pyrrolidinium cations, various piperidinium cations, various imidazolium cations, and various phosphonium cations of the above chemical formulas (26) to (40).

There is no limit to the content of the cation and anion in a combination different from the cation component and anion component of the flexible crystal, as long as the flexible crystal does not have fluidity and is in a solid state when visually observed. The ionic conductivity of the electrolyte layer is further improved by containing a combination of cations and anions different from those of the cationic and anionic components of the flexible crystal. The blending ratio of cations and anions in combinations different from those of the cation component and anion component of the flexible crystals may be equimolar amounts or may be different amounts. Preferably, if the mixing ratio of the ionic liquid is 60 wt % or less, the flexible crystal easily maintains its solid shape.

A flexible crystal may be produced by further adding a polymer. Examples of the polymer include polyethylene oxide (PEO), polypropylene oxide, polyester, and carbonate polymers. Examples of carbonate-based polymers include polyethylene carbonate (PEC), PEC derivatives, polypropylene carbonate, polytrimethylene carbonate, and copolymers of polytrimethylene carbonate and polycarbonate. One type of these polymers may be used alone, or two or more types may be used in combination.

Among these polymers, the carbonate-based polymer is just an example, and any aliphatic polycarbonate can be used. Moreover, when using two or more types in combination, the various polymers may be in the form of a monopolymer, or may exist as a copolymer of two or more types of monomers. Although there is no limitation on the molecular weight of the polymer, the molecular weight of the polymer is preferably 1000k or more, and the molecular weight of polyethylene oxide (PEO) is preferably 1000k or more. By adding these polymers, the mechanical strength of the electrolyte layer can be improved, and the ionic conductivity of the electrolyte layer can also be improved.

This flexible crystal can be produced, for example, by the following manufacturing method, but is not limited to the following, and various methods can be used. That is, the alkali metal salt of the anion component and the halogenated cation component constituting the flexible crystal are each dissolved in a solvent. Examples of alkali metals include Na, K, Li, and Cs. Examples of halogen include F, Cl, Br, and I. Water is preferred as the solvent. An ion exchange reaction is carried out by dropping a solution of an anion metal salt little by little into a solution of halogenated cations. An equimolar amount of the anion metal salt solution is added to the halogenated cation solution and stirred.

At this time, due to ion exchange, flexible crystals are produced and alkali metal halides are produced. When an organic solvent such as dichloromethane is mixed and left to stand, the mixture separates into an aqueous layer and an organic solvent layer. By removing the aqueous layer from the liquid separation, the alkali metal halide is removed. This operation may be repeated multiple times. Thereby, after removing the alkali metal halide, the organic solvent such as dichloromethane is evaporated to obtain flexible crystals.

This flexible crystal is dissolved in a solvent in which the flexible crystal is soluble. The solvent is preferably a polar solvent. Polar solvents include acetonitrile, propylene carbonate, γ-butyrolactone, dimethyl carbonate, ethyl methyl carbonate, ethylene carbonate, sulfolane, acetone, methanol, ethanol, isopropyl alcohol, or mixtures thereof. Since flexible crystals are efficiently dissolved in these polar solvents, the productivity of the electrolyte layer is excellent.

Then, the object to which the electrolyte layer is to be attached is impregnated with a solution of flexible crystals. After being impregnated with a solution of flexible crystals, it is left in a temperature environment such as 100° C. where the solvent evaporates, and the solvent is evaporated by drying, and the remaining water etc. is further evaporated under a temperature environment such as 150° C. As a result, flexible crystals are formed on the object to be adhered.

Incidentally, the flexible crystal may be doped with an ionic salt that becomes an electrolyte. Ionic salts include salts of organic acids, salts of inorganic acids, or salts of complex compounds of organic acids and inorganic acids, and may be used alone or in combination of two or more.

Examples of organic acids include oxalic acid, succinic acid, glutaric acid, pimelic acid, suberic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, adipic acid, benzoic acid, toluic acid, enanthic acid, malonic acid, Examples include carboxylic acids such as 1,6-decanedicarboxylic acid, 1,7-octanedicarboxylic acid, azelaic acid, undecanedioic acid, dodecanedioic acid, and tridecanedioic acid, phenols, and sulfonic acids. Examples of inorganic acids include boric acid, phosphoric acid, phosphorous acid, hypophosphorous acid, carbonic acid, silicic acid, etc., including tetrafluoroborate. Examples of the composite compound of an organic acid and an inorganic acid include borodisalicylic acid, borodioxalic acid, borodiglycolic acid, and the like.

These salts of organic acids, salts of inorganic acids, and at least one salt of a composite compound of organic acids and inorganic acids include ammonium salts, quaternary ammonium salts, quaternized amidinium salts, amine salts, sodium salts, and potassium salts. Examples include salt. Examples of the quaternary ammonium ion of the quaternary ammonium salt include tetramethylammonium, triethylmethylammonium, and tetraethylammonium. Examples of the quaternized amidinium include ethyldimethylimidazolinium and tetramethylimidazolinium. Examples of the amine in the amine salt include primary amines, secondary amines, and tertiary amines. Primary amines include methylamine, ethylamine, propylamine, etc. Secondary amines include dimethylamine, diethylamine, ethylmethylamine, dibutylamine, etc. Tertiary amines include trimethylamine, triethylamine, tripropylamine, tributylamine, Examples include ethyldimethylamine and ethyldiisopropylamine.

Furthermore, an electrolytic capacitor containing a conductive polymer and a flexible crystal in the electrolyte layer has improved capacity compared to a solid electrolytic capacitor containing only a conductive polymer and no flexible crystal. In particular, the content of the flexible crystals is preferably 2 times or more and 12 times or less by weight relative to the content of the conductive polymer. If the content of flexible crystals is more than twice the content of conductive polymer in terms of weight ratio, the electrolytic capacitor will be more durable than a solid electrolytic capacitor that does not contain flexible crystals and only has conductive polymer. Capacitance is improved and ESR is also reduced.

However, from the viewpoint of improving capacitance, the content of flexible crystals may be more than 12 times the weight ratio of the conductive polymer. However, in the process of attaching flexible crystals, a solution of flexible crystals is used, but if the content of flexible crystals exceeds 12 times the weight ratio of the conductive polymer, the solubility of the flexible crystals decreases. However, simple drip impregnation becomes relatively difficult. On the other hand, by setting the content of the flexible crystal to 12 times or less by weight of the conductive polymer, the solubility of the flexible crystal increases. Therefore, by setting the content of the flexible crystal to 12 times or less by weight of the conductive polymer, the process of impregnating the object to which the electrolyte layer is attached with a solution of the flexible crystal becomes simple.

(Separator)
Separators can be made of cellulose such as kraft, Manila hemp, esparto, hemp, rayon, and mixed papers thereof, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and their derivatives, polytetrafluoroethylene resins, and polyfluoride. Polyamide resins such as vinylidene resin, vinylon resin, aliphatic polyamide, semi-aromatic polyamide, and fully aromatic polyamide, polyimide resin, polyethylene resin, polypropylene resin, trimethylpentene resin, polyphenylene sulfide resin, acrylic resin, polyvinyl alcohol These resins can be used alone or in combination.

(Manufacturing method of electrolytic capacitor)
(wound type)
An example of an assembly process for a wound type electrolytic capacitor will be described below. First, a surface-expanding layer is formed on one or both surfaces of the valve metal foil on the anode side, and a dielectric oxide film is formed on the surface-expanding layer by chemical conversion treatment. If necessary, a surface expanding layer is formed on one or both surfaces of the valve metal foil on the cathode side, and an oxide film is formed on the surface. For example, the anode lead and the cathode lead are connected to the anode body and the cathode body by stitching, cold welding, ultrasonic welding, laser welding, or the like.

A long anode body and a cathode body are wound with a separator interposed therebetween to produce a cylindrical wound body. The separators are stacked so that one end thereof protrudes beyond one end of the anode body and the cathode body. The protruding separator is first wound to form a winding core so that the core of the winding body runs along the short sides of the anode body and the cathode body. Then, the core is used as a winding axis, and the long sides of the anode and cathode bodies are rolled up.

After winding, repair the bare metal parts of the valve metal exposed when cutting the anode and cathode bodies to the desired width, as well as defects in the anode and cathode bodies caused by physical stress such as winding. A restoration chemical process will be provided.

In the repair chemical conversion process, the rolled body is immersed in a chemical liquid and a voltage is applied. Chemical liquids include phosphoric acid-based chemical liquids such as ammonium dihydrogen phosphate, boric acid-based chemical liquids such as ammonium borate, adipic acid-based chemical liquids such as ammonium adipate, and boric acid-based chemical liquids such as boric acid and citric acid. A chemical liquid mixed with dicarboxylic acid is used. The voltage is preferably set to a value that is, for example, 0.1 to 1.2 times the chemical formation voltage. Further, as a voltage application method during repair chemical formation, a method of applying a constant voltage from the start of repair chemical formation, a method of increasing the applied voltage stepwise at regular intervals, etc. are appropriately selected.

Next, the process moves to an electrolyte formation step, and an electrolyte layer is formed between the anode body and the cathode body. The electrolyte formation process is roughly divided into a polymer adhesion process and a flexible crystal adhesion process. In the polymer attachment step, a conductive polymer is attached between the anode body and the cathode body, and in the flexible crystal attachment step, a flexible crystal is attached between the anode body and the cathode body.

In the polymer adhesion step using a conductive polymer liquid, the wound body is immersed in the conductive polymer liquid to impregnate the inside of the wound body with the conductive polymer liquid. In order to promote impregnation of the conductive polymer liquid into the wound body, a vacuum treatment or a pressure treatment may be performed as necessary. The impregnation step may be repeated multiple times. After impregnating the wound body with the conductive polymer liquid, the solvent of the conductive polymer liquid is removed by a drying process.

When attaching a conductive polymer while generating a conductive polymer, the rolled body is immersed in a solution of a monomer that becomes the monomer unit of the conductive polymer and an oxidizing agent or a supporting electrolyte to initiate a polymerization reaction. bring about After the conductive polymer is attached, the solvent is removed by a drying process.

Next, in the flexible crystal attachment step, the wound body is immersed in a solution of flexible crystals to impregnate the wound body with the solution of flexible crystals. In order to promote impregnation of the wound body with the flexible crystal solution, a vacuum treatment or a pressure treatment may be performed as necessary. The impregnation step may be repeated multiple times. After the wound body is impregnated with the flexible crystal solution, the solvent is removed by a drying process.

The conductive polymer was attached first to the wound body, and then the flexible crystal was attached later. You can also do this. However, from the viewpoint of forming a conductive path between the anode body and the cathode body, it is preferable to attach the conductive polymer first. By attaching the conductive polymer first, it is possible to uniformly form an electrolyte layer including a flexible crystal and a conductive polymer layer, and it is possible to exhibit good capacity characteristics and good ESR characteristics.

After the conductive polymer and flexible crystal are attached to the anode body, the anode body and the cathode body may be wound so as to face each other with a separator in between. Alternatively, in addition to the anode body, a conductive polymer and a flexible crystal may be attached to the cathode body, the separator, or both, and then the anode body and the cathode body may be wound so as to face each other with the separator in between. .

The capacitor element is housed in an exterior case with a bottom at one end and an open end at the other end, and the capacitor element is sealed in the exterior case with a sealing body. After sealing the capacitor element in the exterior case, the electrolytic capacitor undergoes an aging process to complete its manufacture. In the aging process, a direct current voltage is applied to the electrolytic capacitor to repair defects such as the dielectric oxide film layer.

(Laminated type)
An example of an assembly process for a multilayer type electrolytic capacitor will be described below. First, a surface expanding layer is formed on the surface of the valve metal foil that is the anode body. Next, the foil on which the surface-expanding layer has been formed is subjected to a chemical conversion treatment in a chemical solution to form a dielectric oxide film on the surface of the valve metal foil. An insulating resist layer is printed and dried, including the area that will later become the anode terminal, but excluding the area that will become the anode. That is, an insulating resist layer is printed so that an electrolyte layer is not formed in a region that will become a terminal on the anode side.

After printing the insulating resist layer, proceed to the conductive polymer adhesion step, where the foil is immersed in a conductive polymer liquid and the conductive polymer is adhered to cover the dielectric oxide film. After removing the solvent of the conductive polymer liquid by drying, the conductive polymer liquid is further moved to a flexible crystal attachment step, in which it is immersed in a solution of flexible crystals to further adhere flexible crystals. Then, the solvent of the flexible crystals is removed by drying. An electrolyte layer was formed by such adhesion of the conductive polymer and the adhesion of the flexible crystal.

Next, carbon paste is printed on the electrolyte layer using a screen printer or the like and dried. This drying process forms a carbon layer on the electrolyte layer. Furthermore, a metal paste such as silver paste is printed on the carbon layer and dried. Through this drying process, a silver layer is formed on the carbon layer. These carbon layers and silver layers correspond to the cathode body of an electrolytic capacitor.

After forming the cathode body, the insulating resist layer is peeled off. Note that the insulating resist layer may be peeled off using a mechanical peeling method using laser irradiation or pressing with a jig. The parts exposed by peeling are plated to complete the anode terminal.

The capacitor element thus produced is covered with, for example, a laminate film. Alternatively, the capacitor element is sealed by molding, dip coating, or printing a resin such as a heat-resistant resin or an insulating resin.

Hereinafter, an electrolytic capacitor and its manufacturing method will be explained in more detail based on Examples. Note that the present invention is not limited to the following examples.

(Example 1-4)
Electrolytic capacitors of Examples 1 to 4 and Comparative Example 1 were manufactured in the following manner. First, a pair of electrodes was made using aluminum foil. Both electrode foils were enlarged by etching. One electrode was used as an anode body, and the area was enlarged by direct current etching. In the process of enlarging the surface of the anode body, a direct current was passed through the aluminum foil in an aqueous solution containing hydrochloric acid to form pits, and then a direct current was passed through the aluminum foil in an aqueous solution containing nitric acid to enlarge the diameter of the pits. . The other electrode was used as a cathode body, and the area was enlarged by AC etching. In forming the surface-expanding layer of the cathode body, spongy etched pits were formed by passing an alternating current through the aluminum foil in an aqueous solution containing hydrochloric acid.

A dielectric oxide film was formed on the surface of the foil of the anode body by chemical conversion treatment. In the chemical conversion treatment process, a current with a current density of 10 mA/cm ² was passed in an aqueous ammonium dihydrogen phosphate solution with a concentration of 1.4 g/L and a liquid temperature of 90°C to reach a chemical conversion voltage of 56.5 V. After that, it was held for 10 minutes.

A lead wire was connected to each of the anode body and cathode body, and the anode foil and the cathode foil were wound so as to face each other with a manila paper separator in between. The roll has a diameter of 10 mm and a height of 10 mm. Restorative chemical formation was performed on the wound body by energizing it for 10 minutes at an applied voltage of 56.5 V and a current density of 10 mA in an aqueous ammonium dihydrogen phosphate solution with a liquid temperature of 90°C.

The rolled body was first impregnated with a conductive polymer liquid. The conductive polymer liquid has poly(3,4-ethylenedioxythiophene) (PEDOT/PSS) doped with polystyrene sulfonic acid (PSS) dispersed therein. PEDOT/PSS is added at a rate of 1.2 wt% to the entire conductive polymer liquid. Moreover, ethylene glycol is added to the conductive polymer liquid at a rate of 10 wt% with respect to the conductive polymer dispersion. The wound body was impregnated with this conductive polymer liquid for 10 minutes at room temperature and in a pressurized environment of −0.3 MPa. The impregnation process was performed twice in total.

After the wound body was pulled up from the conductive polymer liquid, it was allowed to stand at room temperature for 10 minutes, and then left to stand still at a temperature of 110° C. for 30 minutes to dry the wound body. As a result, an electrolyte layer containing a conductive polymer was formed on the dielectric oxide film of the anode body.

Next, in Examples 1 to 4, in addition to the conductive polymer, a flexible crystal was attached between the anode body and the cathode body. The flexible crystals of Examples 1 to 4 are shown in Table 1 below.
(Table 1)

As shown in Table 1, in Example 1, P12BF ₄ was attached as a flexible crystal. That is, a flexible crystal containing P12 cation and _BF4 anion in a molar ratio of 1:1 was attached. The P12 cation is an N-ethyl-N-methylpyrrolidinium cation represented by the chemical formula (30).

In Example 2, P12FSA was attached as a flexible crystal. That is, a flexible crystal containing P12 cation and FSA anion in a molar ratio of 1:1 was attached. The FSA anion is a bis(fluorosulfonyl)amide anion represented by the chemical formula (5).

In Example 3, P12BoB was attached as a flexible crystal. That is, a flexible crystal containing P12 cation and BoB anion in a molar ratio of 1:1 was attached. The BoB anion is a bis(oxalato)borate anion represented by the chemical formula (18A).

In Example 4, P12BScB was attached as a flexible crystal. That is, a flexible crystal containing P12 cations and BScB anions in a molar ratio of 1:1 was attached. The BScB anion is a bis(salicylate)borate anion represented by the chemical formula (19A).

The flexible crystals were added to acetonitrile at a ratio of 40 wt% to the total solution. This acetonitrile solution was dropped onto the wound body to impregnate the inside of the wound body with the acetonitrile solution. The amount of impregnation was 570 mg for one rolled body.

After impregnation, the wound body was left standing under an argon atmosphere at 45°C for 2 hours, left standing under an argon atmosphere at 60°C for 2 hours, left standing under an argon atmosphere at 80°C for 2 hours, and finally impregnated with 100°C. The acetonitrile solution was dried by standing for 12 hours under an argon atmosphere at .degree. As a result, in Examples 1 to 4, electrolyte layers containing conductive polymers and flexible crystals were formed. In Comparative Example 1, an electrolyte layer containing a conductive polymer but not containing a flexible crystal was formed.

The capacitor elements of Examples 1 to 4 and Comparative Example 1 were housed in an exterior case, and the opening of the exterior case was sealed with a sealant. The sealing body and the outer case were made to fit tightly together by crimping. Thereafter, the electrolytic capacitors of Examples 1 to 6 and Comparative Example 1 were subjected to aging treatment by applying a voltage of 40.25 V for 1 hour in a temperature environment of 105°C. As a result, electrolytic capacitors with a diameter of 10 mm, a height of 10 mm, a rated voltage of 36 WV, and 270 μF were manufactured.

The capacitance (Cap), equivalent series resistance (ESR), and dielectric loss tangent (tanδ) of the electrolytic capacitors of Examples 1 to 4 and Comparative Example 1 were measured. Cap, tan δ, and ESR were measured at room temperature using an LCR meter (manufactured by NF Circuit Design Block Co., Ltd., model number ZM2376). The measurement frequency of Cap, ESR, and tan δ is 120 Hz, and the alternating current level is a 1.0 Vms sine wave.

The measurement results of Cap, ESR, and tan δ of the electrolytic capacitors of Examples 1 to 4 and Comparative Example 1 are shown in Table 2 below.
(Table 2)

As shown in Table 2, the electrolytic capacitors of Examples 1 to 4 containing conductive polymers and flexible crystals in the electrolyte layer are conductive polymer solid electrolytic capacitors that do not contain flexible crystals and only have conductive polymers. It was confirmed that the capacity was improved compared to Note that the ESR and tan δ of the electrolytic capacitors of Examples 1 to 4 are also within a satisfactory range, and some of the Examples are better than Comparative Example 1.

(Example 5-6)
Electrolytic capacitors of Examples 5 and 6 were manufactured. In Examples 5 and 6, the flexible crystal contained an ionic liquid. Except for the inclusion of the ionic liquid in the flexible crystal, the structure, composition, manufacturing method, and manufacturing conditions of the electrolytic capacitors of Examples 5 and 6 are the same as those of the electrolytic capacitors of Examples 1 to 4.

In Example 5, the flexible crystal is _P12BF4 containing P12 cations and _BF4 anions in a 1:1 molar ratio. The ionic liquid is _EMIBF4 , which contains EMI cations and _BF4 anions in a 1:1 molar ratio. The EMI cation is 1-ethyl-3-methylimidazolium shown by chemical formula (38). P12BF ₄ and EMIBF ₄ were prepared in equimolar amounts.

In Example 6, the flexible crystal is P12FSA containing P12 cations and FSA anions in a 1:1 molar ratio. The ionic liquid is EMIBF ₄ containing EMI cations and FSA anions in a 1:1 molar ratio. P12FSA and EMIFSA were prepared in equimolar amounts.

The capacitance (Cap), equivalent series resistance (ESR), and dielectric loss tangent (tan δ) of the electrolytic capacitors of Examples 5 and 6 were measured under the same conditions as Examples 1 to 4 and Comparative Example 1. The measurement results of Cap, ESR, and tan δ of the electrolytic capacitors of Examples 5 and 6 are shown in Table 3 below.
(Table 3)

As shown in Table 3, when a flexible crystal containing a combination of cations and anions different from the cation and anion components of the flexible crystal is used, the capacity is significantly improved compared to Comparative Example 1. can be confirmed. Furthermore, it can be confirmed that the electrolytic capacitors of Examples 5 and 6 clearly and dramatically reduced ESR and tan δ compared to Comparative Example 1.

(Example 7-9)
Electrolytic capacitors of Examples 7 to 9 and Comparative Example 2 were manufactured. The electrolytic capacitors of Examples 7 to 9 differ from those of Examples 1 to 4 in the type of flexible crystal. The electrolytic capacitor of Comparative Example 2 was manufactured by the same manufacturing method as Comparative Example 1, except for the size of the wound body, and had the same configuration. The rolled bodies of Examples 7 to 9 and Comparative Example 2 differ from Examples 1 to 4 in that they have a diameter of 6.8 mm and a height of 5.8 mm.

In Example 7, P12BScB was attached as a flexible crystal. That is, a flexible crystal containing P12 cations and BScB anions in a molar ratio of 1:1 was attached. The BScB anion is a bis(salicylate)borate anion represented by the chemical formula (19A).

In Example 8, P12BmScB was attached as a flexible crystal. That is, a flexible crystal containing P12 cations and BmScB anions in a molar ratio of 1:1 was attached. The BmScB anion is a bis(methylsalicylate)borate anion represented by the chemical formula (19C).

In Example 9, TEABhNB was attached as a flexible crystal. That is, a flexible crystal containing TEA cations and BhNB anions in a molar ratio of 1:1 was attached. The TEA cation is a tetraethylammonium cation (TEA cation) represented by the chemical formula (27). The BhNB anion is a bis(2-hydroxy-1-naphthorato)borate anion represented by the chemical formula (20B).

The flexible crystals of Examples 7 and 8 were added to γ-butyrolactone in a proportion of 50 wt% based on the total solution. The flexible crystals of Example 9 were added to γ-butyrolactone in a proportion of 25 wt% based on the total solution. This γ-butyrolactone solution was dropped onto the rolled body to impregnate the inside of the rolled body with the γ-butyrolactone solution. The γ-butyrolactone solution was impregnated for 30 minutes at room temperature and in a reduced pressure environment of −80 kPa. At this time, -80 kPa is a gauge pressure based on atmospheric pressure, and the pressure expressed as negative pressure is a gauge pressure based on atmospheric pressure.

After impregnation, the rolled body was left standing at room temperature and a reduced pressure environment of -100 kPa or less overnight, left standing at 45 °C and a reduced pressure environment of -100 kPa or less for 2 hours, and then left at 60 °C and a reduced pressure environment of -100 kPa or less for 2 hours. The γ-butyrolactone solution was left to stand for 2 hours at 80°C and a reduced pressure of -100 kPa or less, and finally left to stand at 90°C and a reduced pressure of -100 kPa or less overnight to thoroughly dry the γ-butyrolactone solution. , γ-butyrolactone was removed. As a result, in Examples 7 to 9, electrolyte layers containing conductive polymers and flexible crystals were formed. In Comparative Example 2, an electrolyte layer containing a conductive polymer but not containing a flexible crystal was formed.

The capacitance (Cap), equivalent series resistance (ESR), and dielectric loss tangent (tanδ) of the electrolytic capacitors of Examples 7 to 9 and Comparative Example 2 were measured. The measurement conditions are the same as in Examples 1 to 4 and Comparative Example 1.

The measurement results of Cap, ESR, and tan δ of the electrolytic capacitors of Examples 7 to 9 and Comparative Example 2 are shown in Table 4 below.
(Table 4)

As shown in Table 4, the electrolytic capacitors of Examples 7 to 9 containing conductive polymers and flexible crystals in the electrolyte layer are conductive polymer solid electrolytic capacitors that do not contain flexible crystals and only have conductive polymers. It was confirmed that the capacity was improved compared to The ESR and tan δ of the electrolytic capacitors of Examples 7 to 9 are also within a satisfactory range, and Example 7 is better than Comparative Example 2.

(Example 10-14)
Electrolytic capacitors of Examples 10 to 14 and Comparative Example 3 were manufactured. In Examples 10 to 14, P12BScB is attached as a flexible crystal, and they are manufactured by the same manufacturing method as Example 7 and have the same configuration. Furthermore, Comparative Example 3 was produced using the same manufacturing method as Comparative Example 1, and has the same configuration. The content of the conductive polymer and the content of the flexible crystal can be determined by measuring the weight before and after each attachment step. The weight was 3 mg.

However, the electrolytic capacitors of Examples 10 to 14 have different weight ratios of the conductive polymer and the flexible crystal. Example 10 contains flexible crystals in a weight ratio of 0.2 times that of the conductive polymer. Example 11 contains flexible crystals in a weight ratio of 1 times that of the conductive polymer. Example 12 contains twice as much flexible crystal by weight as the conductive polymer. Example 13 contains 5 times as much flexible crystal by weight as the conductive polymer. Example 14 contains 12 times as much flexible crystal by weight as the conductive polymer.

The capacitance (Cap) and equivalent series resistance (ESR) of the electrolytic capacitors of Examples 10 to 14 and Comparative Example 3 were measured. Cap, tan δ, and ESR were measured at room temperature using an LCR meter (manufactured by NF Circuit Design Block Co., Ltd., model number ZM2376). The measurement frequency of Cap is 10 kHz, the measurement frequency of ESR is 100 kHz, and the alternating current level is a 1.0 Vms sine wave.

The measurement results of Cap and ESR of the electrolytic capacitors of Examples 10 to 14 and Comparative Example 3 are shown in Table 5 below.
(Table 5)

As shown in Table 5 above, the electrolytic capacitors of Examples 10 to 14 have higher capacitance than Comparative Example 3. Furthermore, the electrolytic capacitors of Examples 10 to 14 have better ESR than Comparative Example 3. In this way, it was confirmed that when the content of flexible crystals is 2 times or more and 12 times or less by weight of the conductive polymer, the capacitance of the electrolytic capacitor is high and the ESR is good. It was done.

Claims (9)

comprising an electrolyte layer containing a conductive polymer and a flexible crystal;
An electrolytic capacitor featuring: the conductive polymer includes poly(3,4-ethylenedioxythiophene) and polystyrene sulfonic acid;
The electrolytic capacitor according to claim 1, characterized in that: the flexible crystal further contains a cation and anion in a different combination from the cation component and anion component of the flexible crystal;
The electrolytic capacitor according to claim 1 or 2, characterized in that: The amount of the flexible crystal is 2 times or more and 12 times or less in weight ratio when the amount of the conductive polymer is 1;
The electrolytic capacitor according to claim 1 or 2, characterized in that: Including an electrolyte layer forming step of forming an electrolyte layer between a pair of electrodes,
The electrolyte forming step includes:
a polymer adhesion step of adhering a conductive polymer to one or both of the pair of electrodes;
a flexible crystal attachment step of attaching a flexible crystal to one or both of the pair of electrodes;
to have,
A method for manufacturing an electrolytic capacitor characterized by: One of the pair of electrodes is a valve metal foil body, and an anode body having a dielectric oxide film formed on the foil,
the other of the pair of electrodes is a cathode body;
6. The method of manufacturing an electrolytic capacitor according to claim 5. The polymer adhesion step includes an impregnation step of impregnating a liquid containing the conductive polymer between the pair of electrodes;
The method for manufacturing an electrolytic capacitor according to claim 5 or 6, characterized in that: In the flexible crystal attachment step, attaching the flexible crystal containing a cation and anion in a different combination from the cation component and anion component of the flexible crystal;
The method for manufacturing an electrolytic capacitor according to claim 5 or 6, characterized in that: In the flexible crystal attachment step, the amount of the flexible crystal is deposited at a weight ratio of 2 times or more and 12 times or less when the amount of the conductive polymer is 1;
The method for manufacturing an electrolytic capacitor according to claim 5 or 6, characterized in that: