JP2023138354A - Electrolyte for hybrid electrolytic capacitor and hybrid electrolytic capacitor - Google Patents

Abstract

To provide an electrolyte for a hybrid electrolytic capacitor that can suppress an increase in ESR in a high-temperature environment and achieve a high withstand voltage.SOLUTION: An electrolyte for a hybrid electrolytic capacitor contains at least one carboxylic acid selected from the group consisting of carboxylic acids represented by a plurality of predetermined formulas and an aromatic carboxylic acid having a molecular weight of 250 or less.SELECTED DRAWING: None

Description

The present invention relates to an electrolytic solution for a hybrid electrolytic capacitor and a hybrid electrolytic capacitor containing this electrolytic solution.

Hybrid electrolytic capacitors are widely used in various electrical and electronic products, and have a wide range of uses, including charge storage, noise removal, and phase adjustment. In recent years, their use in automotive applications has increased, and the need for higher voltage resistance has increased, and various improvements have been attempted.

For example, Patent Document 1 discloses a technique for increasing the voltage resistance of a capacitor by using an aliphatic carboxylic acid or a composite compound of an inorganic acid and an organic acid as an anion in an electrolytic solution.
Furthermore, Patent Document 2 discloses a technique for improving the ESR (equivalent series resistance) of a capacitor by using an aliphatic carboxylic acid ammonium salt in an electrolytic solution.

However, although the electrolytic capacitors described in Patent Documents 1 and 2 can have a high withstand voltage, the withstand voltage is not sufficient, and the ESR characteristics in a high temperature environment are not sufficient.

Japanese Patent Application Publication No. 2015-165550 JP2017-38010A

An object of the present invention is to provide an electrolytic solution for a hybrid electrolytic capacitor that can suppress an increase in ESR in a high-temperature environment and achieve a high withstand voltage.

The present inventor has arrived at the present invention as a result of intensive studies to solve the above problems.
That is, the present invention provides carboxylic acids (A1) represented by general formula (1), carboxylic acids (A2) represented by general formula (2), and carboxylic acids (A3) represented by general formula (3). An electrolytic solution for a hybrid electrolytic capacitor containing at least one selected carboxylic acid (A) and an aromatic carboxylic acid (B) having a molecular weight of 250 or less, wherein the weight of the carboxylic acid (A) and the aromatic This is an electrolytic solution for a hybrid electrolytic capacitor in which the ratio (A/B) of the group carboxylic acid (B) to the weight is 1 to 10,000.

［式（１）中、Ｒ^１は置換基を有してもよい炭素数２～１０の炭化水素から水素原子を２つ除いた残基又はオキシアルキレン繰り返し単位のアルキレン基の炭素数が２～６であるポリアルキレングリコールから２つのヒドロキシ基を除いた残基である。］

[In formula (1), R ¹ is a residue obtained by removing two hydrogen atoms from a hydrocarbon having 2 to 10 carbon atoms which may have a substituent, or an alkylene group of an oxyalkylene repeating unit having 2 to 10 carbon atoms] It is a residue obtained by removing two hydroxy groups from polyalkylene glycol 6. ]

［式（２）中、Ｒ^２は置換基を有してもよい炭素数２～１０の炭化水素から水素原子を２つ除いた残基又はオキシアルキレン繰り返し単位のアルキレン基の炭素数が２～６であるポリアルキレングリコールから２つのヒドロキシ基を除いた残基である。］

[In formula (2), R ² is a residue obtained by removing two hydrogen atoms from a hydrocarbon having 2 to 10 carbon atoms which may have a substituent, or an alkylene group of an oxyalkylene repeating unit having 2 to 10 carbon atoms] It is a residue obtained by removing two hydroxy groups from polyalkylene glycol 6. ]

［式（３）中、Ｒ^３は置換基を有してもよい炭素数２～１０の炭化水素から水素原子を２つ除いた残基又はオキシアルキレン繰り返し単位のアルキレン基の炭素数が２～６であるポリアルキレングリコールから２つのヒドロキシ基を除いた残基である。］

[In formula (3), R ³ is a residue obtained by removing two hydrogen atoms from a hydrocarbon having 2 to 10 carbon atoms which may have a substituent, or an alkylene group of an oxyalkylene repeating unit having 2 to 10 carbon atoms] It is a residue obtained by removing two hydroxy groups from polyalkylene glycol 6. ]

An electrolytic capacitor using the electrolytic solution for electrolytic capacitors of the present invention has the effect of suppressing an increase in ESR in a high-temperature environment and achieving a high withstand voltage.

The electrolytic solution for a hybrid electrolytic capacitor of the present invention comprises a carboxylic acid (A1) represented by general formula (1), a carboxylic acid (A2) represented by general formula (2), and a carboxylic acid represented by general formula (3). Contains at least one carboxylic acid (A) selected from the group consisting of (A3).

The carboxylic acid (A1) of the present invention is a carboxylic acid represented by the general formula (1).
R ¹ in general formula (1) is a residue obtained by removing two hydrogen atoms from a hydrocarbon having 2 to 10 carbon atoms which may have a substituent, or an alkylene group of an oxyalkylene repeating unit having 2 to 6 carbon atoms. It is a residue obtained by removing two hydroxy groups from polyalkylene glycol.
Examples of hydrocarbons having 2 to 10 carbon atoms that may have a substituent include ethane, propane, butane, pentane, hexane, heptane, octane, nonane, and decane, and those in which the hydrogen atom of these hydrocarbons is replaced with a substituent. Things can be mentioned.
Examples of the substituent include halogen atoms (fluorine atoms, chlorine atoms, bromine atoms, etc.), hydroxy groups, and alkoxy groups having 1 to 4 carbon atoms.

The carboxylic acid (A1) can be represented as an ester compound of two aromatic dicarboxylic acids (a11) at both ends and a diol (a2) serving as a linker site connecting them.

Examples of the aromatic dicarboxylic acid (a11) include phthalic acid (including phthalic anhydride), isophthalic acid, and terephthalic acid.
Among the aromatic dicarboxylic acids (a11), phthalic acid (including phthalic anhydride) and terephthalic acid are preferred, and more preferred are phthalic acid (including phthalic anhydride) and terephthalic acid, from the viewpoint of suppressing the increase in ESR in a high-temperature environment and solubility in the solvent described below. Phthalic acid (including phthalic anhydride).

The diol (a2) includes ethylene glycol, propylene glycol, 1,4-butanediol, 1,10-butanediol, pentanediol, hexanediol, heptanediol, octanediol, nonanediol and decanediol, and oxyalkylene repeating units. Examples include polyalkylene glycols in which the alkylene group has 2 to 6 carbon atoms.

Examples of polyalkylene glycols in which the alkylene group of the oxyalkylene repeating unit has 2 to 6 carbon atoms include polyethylene glycol, polypropylene glycol, polybutylene glycol, polytetramethylene glycol, and the like.
In the case of polyalkylene glycol, the number of oxyalkylene repeating units is 2 or more, and the number average molecular weight of the polyalkylene glycol is preferably 2000 or less, more preferably 1000 or less, from the viewpoints of withstand voltage and solubility.

The diol (a2) is preferably polyethylene glycol, polypropylene glycol, polybutylene glycol, and polytetramethylene glycol, more preferably polyethylene glycol and polypropylene glycol, from the viewpoint of withstand voltage and solubility in the solvent described below. .

The carboxylic acid (A2) of the present invention is a carboxylic acid represented by the general formula (2).
R ² in the general formula (2) is a residue obtained by removing two hydrogen atoms from a hydrocarbon having 2 to 10 carbon atoms which may have a substituent, or an alkylene group of an oxyalkylene repeating unit having 2 to 6 carbon atoms. It is a residue obtained by removing two hydroxy groups from polyalkylene glycol.
Examples of hydrocarbons having 2 to 10 carbon atoms that may have a substituent include ethane, propane, butane, pentane, hexane, heptane, octane, nonane, and decane, and those in which the hydrogen atom of these hydrocarbons is replaced with a substituent. Things can be mentioned.
Examples of the substituent include halogen atoms (fluorine atoms, chlorine atoms, bromine atoms, etc.), hydroxy groups, and alkoxy groups having 1 to 4 carbon atoms.

Examples of polyalkylene glycols in which the alkylene group of the oxyalkylene repeating unit has 2 to 6 carbon atoms include polyethylene glycol, polypropylene glycol, polybutylene glycol, and polytetramethylene glycol.

The carboxylic acid (A2) can be represented as an amide compound of two aromatic dicarboxylic acid sites (a1) at both ends and a diamine (a3) serving as a linker site connecting them.

Examples of the aromatic dicarboxylic acid moiety (a1) include phthalic acid (including phthalic anhydride), isophthalic acid, and terephthalic acid.

The aromatic dicarboxylic acid moiety (a1) is preferably phthalic acid (including phthalic anhydride) and terephthalic acid, from the viewpoint of suppressing the increase in ESR in a high-temperature environment and solubility in the solvent described below. More preferred is phthalic acid (including phthalic anhydride).

Examples of the diamine (a3) include diamines such as ethylene diamine, hexaethylene diamine, and polyether diamine having a number average molecular weight of 2000 or less.
Examples of polyether diamines having a number average molecular weight of 2000 or less include 1,2-bis(2-aminoethoxy)ethane, bis(2-aminoethyl)polyethylene glycol, bis(2-aminopropyl)polypropylene glycol, and bis(2-aminopropyl)polypropylene glycol. butyl) polypolybutylene glycol and bis(2-aminobutyl) polytetramethylene glycol.

Among the diamines (a3), polyether diamines with a number average molecular weight of 2000 or less are preferred, and polyether diamines with a number average molecular weight of 1000 or less are more preferred from the viewpoint of withstand voltage and solubility in solvents described below.

The carboxylic acid (A3) of the present invention is a carboxylic acid represented by the general formula (3).
R ³ in general formula (3) is a residue obtained by removing two hydrogen atoms from a hydrocarbon having 2 to 10 carbon atoms which may have a substituent, or an alkylene group of an oxyalkylene repeating unit having 2 to 6 carbon atoms. It is a residue obtained by removing two hydroxy groups from polyalkylene glycol.
Examples of hydrocarbons having 2 to 10 carbon atoms that may have a substituent include ethane, propane, butane, pentane, hexane, heptane, octane, nonane, and decane, and those in which the hydrogen atom of these hydrocarbons is replaced with a substituent. Things can be mentioned.
Examples of the substituent include halogen atoms (fluorine atoms, chlorine atoms, bromine atoms, etc.), hydroxy groups, and alkoxy groups having 1 to 4 carbon atoms.

Examples of polyalkylene glycols in which the alkylene group of the oxyalkylene repeating unit has 2 to 6 carbon atoms include polyethylene glycol, polypropylene glycol, polybutylene glycol, and polytetramethylene glycol.

The carboxylic acid (A3) can be represented as an imide compound of two aromatic tricarboxylic acid sites (a12) at both ends and a diamine (a3) serving as a linker site connecting them.

Examples of the aromatic tricarboxylic acid moiety (a12) include trimellitic acid (including trimellitic anhydride).

The aromatic tricarboxylic acid moiety (a12) is preferably trimellitic acid (including trimellitic anhydride) from the viewpoint of suppressing the increase in ESR in a high-temperature environment and solubility in the solvent described below.

Examples of the diamine (a3) include diamines such as ethylene diamine, hexaethylene diamine, and polyether diamine having a number average molecular weight of 2000 or less.
Examples of polyether diamines having a number average molecular weight of 2000 or less include 1,2-bis(2-aminoethoxy)ethane, bis(2-aminoethyl)polyethylene glycol, bis(2-aminopropyl)polypropylene glycol, and bis(2-aminopropyl)polypropylene glycol. butyl) polypolybutylene glycol and bis(2-aminobutyl) polytetramethylene glycol.

Among the diamines (a3), polyether diamines with a number average molecular weight of 2000 or less are preferred, and polyether diamines with a number average molecular weight of 1000 or less are more preferred from the viewpoint of withstand voltage and solubility in solvents described below.

Aromatic carboxylic acids (B) having a molecular weight of 250 or less include benzoic acid (molecular weight 122), phthalic acid (molecular weight 166), isophthalic acid (molecular weight 166), terephthalic acid (molecular weight 166), 2-furancarboxylic acid (molecular weight 112), 3-furancarboxylic acid (molecular weight 112), 2,5-furandicarboxylic acid (molecular weight 156), 1,2-naphthalene dicarboxylic acid (molecular weight 216), 1,4-naphthalene dicarboxylic acid (molecular weight 216), 1 , 5-naphthalene dicarboxylic acid (molecular weight 216), 1,8-naphthalene dicarboxylic acid (molecular weight 216), 2,3-naphthalene dicarboxylic acid (molecular weight 216), 2,6-naphthalene dicarboxylic acid (molecular weight 216) and trimellitic acid (molecular weight 210), etc.

The aromatic carboxylic acid (B) is preferably benzoic acid, phthalic acid, and 2,5-furandicarboxylic acid, and more preferably phthalic acid, from the viewpoint of suppressing an increase in ESR in a high-temperature environment.

The electrolytic solution for a hybrid electrolytic capacitor of the present invention does not contain an acid (A') other than the carboxylic acid (A1), the carboxylic acid (A2), the carboxylic acid (A3), and the aromatic carboxylic acid (B). It's okay to stay. Examples of the acid (A') include aliphatic carboxylic acids (adipic acid, sebacic acid, azelaic acid, 1,6-decanedicarboxylic acid), phosphoric acid (phosphoric acid, diphosphorous acid, phosphoric acid ester), and boric acid ( Examples include acids such as boric acid, boric esters, and borodisalicylic acid.
Among these acids (A'), from the viewpoint of increasing withstand voltage, aliphatic carboxylic acids are preferred, azelaic acid and boric acid are more preferred, and azelaic acid is particularly preferred.
These acids (A') may be used alone or in combination of two or more.

Even if the carboxylic acid (A1), carboxylic acid (A2), carboxylic acid (A3), aromatic carboxylic acid (B) and acid (A') are contained in the form of an acid, they are ionized and contained as an anion. Either is fine.
Counter cations of anions include ammonium, primary ammonium, secondary ammonium, tertiary ammonium and amidinium. Examples of ammonium, primary ammonium, secondary ammonium, and tertiary ammonium include ammonium produced from ammonia, primary amine, secondary amine, and tertiary amine, respectively.
These amines include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, N,N-diisopropylethylamine, tetramethylethylenediamine, hexamethylenediamine, spermidine, spermine, amantadine, aniline, phenethylamine, toluidine, pyrrolidine, Examples include piperidine, piperazine, morpholine, imidazole, pyridine, pyridazine, pyrimidine, pyrazine, 4-dimethylaminopyridine and triethanolamine.
Amidinium includes 1,3-dimethylimidazolium, 1,3-diisopropylimidazolium, 1,3-dibutylimidazolium, 1-methyl-3-propylimidazolium, 1-ethyl-3-methylimidazolium, 1- Examples include ethyl-2,3-dimethylimidazolium, 1-butyl-3-methylimidazolium, and 1-benzyl-3-methylimidazolium. These may be used alone or in combination of two or more.

The counter cation of the anion is preferably ammonium, primary ammonium, or tertiary ammonium, and more preferably tertiary ammonium, from the viewpoint of suppressing an increase in ESR.

The electrolytic solution for a hybrid electrolytic capacitor of the present invention can further contain a solvent.
Examples of solvents include alcohol solvents [methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, ethylene glycol, ethylene glycol monobutyl ether, propylene glycol, diethylene glycol, glycerin, polyethylene glycol, polypropylene glycol, etc.], amide solvents (N-methylformamide, N-ethylformamide and N,N-dimethylformamide, etc.), lactone solvents (α-acetyl-γ-butyrolactone, β-butyrolactone, γ-butyrolactone, γ-valerolactone, δ-valerolactone, etc.), nitrile solvents (acetonitrile, propionitrile, butyronitrile, acrylonitrile, methacrylnitrile, benzonitrile, etc.), sulfoxide solvents (dimethylsulfoxide, methylethylsulfoxide, diethylsulfoxide), and sulfone solvents (sulfolane, ethylmethylsulfone, etc.).
Among the solvents, alcohol solvents and lactone solvents are preferred from the viewpoint of suppressing an increase in ESR, more preferred are ethylene glycol, propylene glycol, diethylene glycol, and glycerin, and particularly preferred is ethylene glycol.
These solvents may be used alone or in combination of two or more.

The pH of the electrolytic solution at 25° C. is preferably 4 to 6, more preferably 4 to 5.5, particularly preferably 4 to 5, from the viewpoint of suppressing the increase in ESR and spark voltage.
The pH of the electrolytic solution at 25° C. is a value directly measured with a pH meter.

In the electrolytic solution for a hybrid electrolytic capacitor of the present invention, based on the total weight of the electrolytic solution for a hybrid electrolytic capacitor, the weight ratio of the carboxylic acid (A) is determined to suppress an increase in ESR in a high-temperature environment and dissolve it in the solvent. From the viewpoint of properties, the content is preferably 0.05 to 40% by weight, more preferably 1 to 30% by weight, particularly preferably 1 to 20% by weight.
Based on the total weight of the electrolytic solution for a hybrid electrolytic capacitor, the weight ratio of the aromatic carboxylic acid (B) having a molecular weight of 250 or less is preferably 0.01 to 40 from the viewpoint of suppressing an increase in ESR in a high temperature environment. % by weight, more preferably 0.05 to 20% by weight, particularly preferably 0.05 to 10% by weight.
In the electrolytic solution for a hybrid electrolytic capacitor of the present invention, based on the total weight of the electrolytic solution for a hybrid electrolytic capacitor, the weight ratio of the acid (A') is set to suppress an increase in ESR in a high-temperature environment and dissolve it in the solvent. From the viewpoint of properties, the content is preferably 10% by weight or less, more preferably 5% by weight or less, particularly preferably 1% by weight or less.

In the electrolytic solution for a hybrid electrolytic capacitor of the present invention, the ratio (A/B) of the weight of carboxylic acid (A) to the weight of aromatic carboxylic acid (B) is 1 to 10,000, preferably 1 to 1,000. be. If it is less than 1, the withstand voltage will be poor, and if it exceeds 10,000, it will be poor in terms of withstand voltage and suppression of swelling after aging of the capacitor element.

The electrolytic solution for a hybrid electrolytic capacitor of the present invention preferably has a moisture content of 0.05 to 40% by weight, more preferably 0.5 to 3% by weight, based on the weight of the electrolytic solution from the viewpoint of spark voltage. It is 0% by weight.

The hybrid electrolytic capacitor of the present invention is formed from a capacitor element having an anode foil having a dielectric layer on its surface and a solid electrolyte (C) layer in contact with the dielectric layer of the anode foil. It is.
The capacitor element is impregnated with the electrolytic solution for the hybrid electrolytic capacitor, and the solid electrolyte (C) contains a conductive polymer.
It has a capacitor element, a pair of lead wires, and an exterior body. Each of the pair of lead wires is connected to a capacitor element. The exterior body encapsulates the capacitor element with the other end of the lead wire led out.
The exterior body consists of a cylindrical case and a sealing body. This case houses a capacitor element impregnated with electrolyte, and the sealing body has through-holes through which the lead wires are inserted. It is sealed by compressing it with a drawing section provided on the outer peripheral surface of the tube.

The anode foil is made by roughening aluminum foil by edging and then forming an anodic oxide film, which is a dielectric, on the surface of the foil by chemical conversion treatment, resulting in an anode foil having a dielectric layer on the surface.
In addition to the anode foil, the capacitor element also has a cathode foil and a separator, and the capacitor element is constructed by laminating and winding the anode foil, the cathode foil, and the separator. Then, a layer of solid electrolyte (C) containing a conductive polymer is created between the anode foil and the cathode foil. Examples of the preparation method include a method of impregnating it with a conductive polymer solution and then drying it, and a method of electrolytically polymerizing the conductive polymer.
The electrolytic solution enters the gap in the solid electrolyte (C) formed in the capacitor element formed as described above, thereby creating a hybrid electrolytic capacitor.

The hybrid electrolytic capacitor only needs to contain the electrolytic solution for electrolytic capacitors, and its shape, size, etc. are not limited. The hybrid electrolytic capacitor of the present invention is, for example, a rolled-up electrolytic capacitor in which a separator is interposed between an anode (aluminum oxide foil) having aluminum oxide formed on the anode surface and a cathode aluminum foil. An example of this is a capacitor constructed by winding the capacitor.
For example, after impregnating a separator (kraft paper, manila paper, etc.) with the electrolytic solution for an electrolytic capacitor of the present invention as a driving electrolytic solution and storing it together with an anode and a cathode in a bottomed cylindrical aluminum case, the opening of the aluminum case is It can be obtained by sealing with sealing rubber (butyl rubber, silicone rubber, etc.).

In the present invention, the solid electrolyte (C) contains a conductive polymer.
Examples of conductive polymers include (co)polymers having constituent monomers such as thiophene, 3,4-ethylenedioxythiophene, alkylated ethylenedioxythiophene, alkoxylated ethylenedioxythiophene, pyrrole, and aniline. It will be done.
The conductive polymer may be used alone or in combination of two types.

A hybrid electrolytic capacitor using the electrolytic solution for a hybrid electrolytic capacitor of the present invention is not only excellent in that it can reduce initial ESR, but also excellent in that it can suppress an increase in ESR at high temperatures. The following is presumed to be the mechanism by which the increase in ESR at high temperatures can be suppressed.
The deterioration in performance of conventional electrolyte solutions for hybrid electrolytic capacitors (decreased ESR retention rate, etc.) is thought to be caused by oxidation deterioration, dedoping, etc. of the conductive polymer constituting the solid electrolyte.
Here, in the electrolyte solution for a hybrid electrolytic capacitor of the present invention, oxygen atoms on the furan skeleton of the carboxylic acid anion (A) act on the electrolyte, resulting in oxidative deterioration that causes performance deterioration of the electrolyte. It is considered that dedoping and dedoping can be suppressed.

<Others>
The present invention may include the following configurations.
<1> Selected from the group consisting of carboxylic acid (A1) represented by general formula (1), carboxylic acid (A2) represented by general formula (2), and carboxylic acid (A3) represented by general formula (3) An electrolytic solution for a hybrid electrolytic capacitor containing at least one carboxylic acid (A) and an aromatic carboxylic acid (B) having a molecular weight of 250 or less, wherein the weight of the carboxylic acid (A) and the aromatic carboxylic acid (B) are An electrolytic solution for a hybrid electrolytic capacitor having an acid (B) to weight ratio (A/B) of 1 to 10,000.

［式（１）中、Ｒ^１は置換基を有してもよい炭素数２～１０の炭化水素から水素原子を２つ除いた残基又はオキシアルキレン繰り返し単位のアルキレン基の炭素数が２～６であるポリアルキレングリコールから２つのヒドロキシ基を除いた残基である。］

[In formula (1), R ¹ is a residue obtained by removing two hydrogen atoms from a hydrocarbon having 2 to 10 carbon atoms which may have a substituent, or an alkylene group of an oxyalkylene repeating unit having 2 to 10 carbon atoms] It is a residue obtained by removing two hydroxy groups from polyalkylene glycol 6. ]

［式（２）中、Ｒ^２は置換基を有してもよい炭素数２～１０の炭化水素から水素原子を２つ除いた残基又はオキシアルキレン繰り返し単位のアルキレン基の炭素数が２～６であるポリアルキレングリコールから２つのヒドロキシ基を除いた残基である。］

[In formula (2), R ² is a residue obtained by removing two hydrogen atoms from a hydrocarbon having 2 to 10 carbon atoms which may have a substituent, or an alkylene group of an oxyalkylene repeating unit having 2 to 10 carbon atoms] It is a residue obtained by removing two hydroxy groups from polyalkylene glycol 6. ]

［式（３）中、Ｒ^３は置換基を有してもよい炭素数２～１０の炭化水素から水素原子を２つ除いた残基又はオキシアルキレン繰り返し単位のアルキレン基の炭素数が２～６であるポリアルキレングリコールから２つのヒドロキシ基を除いた残基である。］
＜２＞２５℃における電解液のｐＨが４～６である＜１＞に記載のハイブリッド型電解コンデンサ用電解液。
＜３＞電解液の重量に基づいて水分量が０.０５～４０重量％である＜１＞又は＜２＞に記載のハイブリッド型電解コンデンサ用電解液。
＜４＞表面に誘電体層を有する陽極箔と、この陽極箔の誘電体層に接触した固体電解質（Ｃ）の層とを有するコンデンサ素子から形成されるハイブリッド型電解コンデンサであって、前記コンデンサ素子には＜１＞～＜３＞いずれか１項に記載のハイブリッド型電解コンデンサ用電解液が含侵されており、前記固体電解質（Ｃ）が導電性高分子を含むハイブリッド型電解コンデンサ。

[In formula (3), R ³ is a residue obtained by removing two hydrogen atoms from a hydrocarbon having 2 to 10 carbon atoms which may have a substituent, or an alkylene group of an oxyalkylene repeating unit having 2 to 10 carbon atoms] It is a residue obtained by removing two hydroxy groups from polyalkylene glycol 6. ]
<2> The electrolytic solution for a hybrid electrolytic capacitor according to <1>, wherein the electrolytic solution has a pH of 4 to 6 at 25°C.
<3> The electrolytic solution for a hybrid electrolytic capacitor according to <1> or <2>, wherein the water content is 0.05 to 40% by weight based on the weight of the electrolytic solution.
<4> A hybrid electrolytic capacitor formed from a capacitor element having an anode foil having a dielectric layer on its surface and a solid electrolyte (C) layer in contact with the dielectric layer of the anode foil, the capacitor A hybrid electrolytic capacitor, wherein the element is impregnated with the electrolytic solution for a hybrid electrolytic capacitor according to any one of <1> to <3>, wherein the solid electrolyte (C) contains a conductive polymer.

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples.

<Manufacture example 1>
80 parts by weight of diethyl ether and 86.7 parts by weight (2 mol equivalent) of phthalic anhydride were placed in a Kolben, and 13.3 parts by weight (1 mol equivalent) of ethylene glycol was added dropwise to cause a condensation reaction. Thereafter, diethyl ether was removed under reduced pressure (0.5 kPa) at 40° C. to obtain a carboxylic acid (A1-1) in which R ¹ is a residue obtained by removing two hydrogen atoms from ethane (ethylene group).

<Manufacture example 2>
140 parts by weight of dibutyl ether, 88.3 parts by weight (2 mol equivalent) of terephthalic acid, and 11.7 parts by weight (1 mol equivalent) of ethylene glycol were charged into a Kolben and heated at 140° C. for 3 hours to cause a condensation reaction. Thereafter, dibutyl ether was removed under reduced pressure (0.5 kPa) at 100° C. to obtain a carboxylic acid (A1-2) in which R ¹ is a residue (ethylene group) obtained by removing two hydrogen atoms from ethane.

<Manufacture example 3>
In Production Example 1, the charged weight of phthalic anhydride was 59.0 parts by weight (2 mol equivalent), and 41.0 parts by weight of ethylene glycol was added to PEG200 [polyethylene glycol, number average molecular weight 200, manufactured by Sanyo Chemical Industries, Ltd.]. Carboxylic acid (A1-3) in which R ¹ is a residue obtained by removing two hydroxy groups from polyethylene glycol (number average molecular weight 200) was obtained in the same manner as in Production Example 1 except that the amount was changed to 1 mol equivalent). Ta.

<Manufacture example 4>
In Production Example 1, the charged weight of phthalic anhydride was 22.4 parts by weight (2 mol equivalent), and 77.6 parts by weight of ethylene glycol was added to PEG1000 [polyethylene glycol, number average molecular weight 1000, manufactured by Sanyo Chemical Industries, Ltd.]. Carboxylic acid (A1-4) in which R ¹ is a residue obtained by removing two hydroxy groups from polyethylene glycol (number average molecular weight 1000) was obtained in the same manner as in Production Example 1 except that the amount was changed to 1 mol equivalent). Ta.

<Manufacture example 5>
Production Example 1 except that the charged weight of phthalic anhydride in Production Example 1 was changed to 62.3 parts by weight (2 mol equivalent) and the ethylene glycol was changed to 37.7 parts by weight (1 mol equivalent) of 1,6-decanediol. In the same manner as above, an acid (A1-5) in which R ¹ is a residue obtained by removing two hydroxy groups from 1,6-decanediol was obtained.

<Manufacture example 6>
Produced in the same manner as in Production Example 1, except that the weight of phthalic anhydride was changed to 82.8 parts by weight (2 mol equivalent) and the ethylene glycol was changed to 17.2 parts by weight (1 mol equivalent) of ethylenediamine. , a carboxylic acid (A2-1) in which R ² is a residue obtained by removing two hydrogen atoms from ethane (ethylene group) was obtained.

<Manufacture example 7>
In the same manner as in Production Example 1, except that the charged weight of phthalic anhydride was changed to 71.3 parts by weight (2 mol equivalent) and the ethylene glycol was changed to 28.7 parts by weight (1 mol equivalent) of hexaethylenediamine. A carboxylic acid (A2-2) in which R ² is a residue obtained by removing two hydrogen atoms from hexane (1,6-hexylene group) was obtained.

<Manufacture example 8>
In Production Example 1, the charged weight of phthalic anhydride was changed to 66.1 parts by weight (2 mol equivalent), and the ethylene glycol was changed to 33.9 parts by weight (1 mol equivalent) of 1,2-bis(2-aminoethoxy)ethane. A carboxylic acid (A2-3) in which R ² is a residue obtained by removing two hydroxy groups from tripropylene glycol was obtained in the same manner as in Production Example 1 except for the following steps.

<Manufacture example 9>
In Production Example 1, the charged weight of phthalic anhydride was 12.6 parts by weight (2 mol equivalent), and 87.4 parts by weight of bis(2-aminopropyl) polypropylene glycol [Polyetheramine D2000, manufactured by Mitsui Chemicals, Inc.] (1 mol equivalent) was carried out in the same manner as in Production Example 1, and R ² was a carboxylic acid (A2-4) which is a residue obtained by removing two hydroxy groups from polypropylene glycol (number average molecular weight 2000). Obtained.

<Manufacture example 10>
140 parts by weight of dibutyl ether, 76.8 parts by weight (2 mol equivalent) of trimellitic anhydride, and 23.2 parts by weight (1 mol equivalent) of hexaethylenediamine were put into a Kolben, and heated at 140°C for 3 hours to cause a condensation reaction. . Thereafter, dibutyl ether was removed under reduced pressure (0.5 kPa) at 100°C, and R ³ was a carboxylic acid (A3-1) which is a residue obtained by removing two hydrogen atoms from hexane (1,6-hexylene group). ) was obtained.

<Manufacture example 11>
In Production Example 10, the charged weight of trimellitic anhydride was 16.1 parts by weight (2 mol equivalent), and 83.9 parts by weight of bis(2-aminopropyl) polypropylene glycol [Polyetheramine D2000, manufactured by Mitsui Chemicals, Inc.] Carboxylic acid (A3-2) in which R ³ is a residue obtained by removing two hydroxy groups from polypropylene glycol (number average molecular weight 2000) I got it.

<Examples 1 to 22, Comparative Examples 1 to 4>
<Preparation of electrolyte solution for hybrid capacitor>
Mix the composition in the parts by weight listed in Table 2 or 3, remove carbon dioxide by degassing under reduced pressure if necessary, and electrolyte solution for hybrid type capacitors (Y-1) to (Y-22) and comparative hybrid type capacitors. Electrolytes (Y'-1) to (Y'-4) were prepared. Note that for 1,2,3,4-tetramethylimidazolinium/methyl carbonate, the number of parts by weight is stated excluding carbonic acid generated by reaction with acid.

The abbreviations in Tables 2 and 3 are as follows.
GBL: γ-butyrolactone SL: Sulfolane EG: Ethylene glycol PEG300: Polyethylene glycol, number average molecular weight 300, manufactured by Sanyo Chemical Industries, Ltd. Propylene glycol 400: Propylene glycol, number average molecular weight 400, manufactured by Sanyo Chemical Industries, Ltd. PEG1000: Polyethylene glycol, number average molecular weight 1000, manufactured by Sanyo Chemical Industries, Ltd.

<Production of hybrid electrolytic capacitor>
Electrode tabs were connected to an anode foil (formed aluminum foil: manufactured by JCC, 115HD-658Vf) and a cathode foil (unformed aluminum foil: manufactured by JCC, 30CB) having a dielectric layer, and kraft paper was used as a separator. An element was obtained by facing each other. In order to repair the cut surface and the defective part, repair chemical formation was performed on the element in an ammonium borate aqueous solution at a voltage of 500 V, and a capacitor element (theoretical capacity: 10.0 μF) was obtained.
Next, the capacitor element was vacuum impregnated for 1 minute in a PEDOT/PSS aqueous dispersion (containing a polymer containing 3,4-ethylenedioxythiophene as a constituent monomer and polystyrene sulfonic acid) (manufactured by Heraeus: Clevios PH500). Degree of vacuum: 20 mmHg) and dried at 150° C. for 30 minutes to form a solid electrolyte layer on the surface of the dielectric layer.
Subsequently, the electrolytes for hybrid capacitors of Examples and Comparative Examples shown in Table 2 were impregnated in vacuum at 50° C. for 1 minute (degree of vacuum: 20 mmHg).
Finally, the capacitor element having a solid electrolyte layer and impregnated with an electrolytic solution was housed in a case and caulked to obtain hybrid electrolytic capacitors of Examples and Comparative Examples.

The hybrid electrolytic capacitors obtained in Examples and Comparative Examples were evaluated for "capacitor withstand voltage" before high temperature test (initial stage), "swelling after aging", "ESR", and "capacity" using the following methods. The results are shown in Table 4.
<Capacitor withstand voltage>
At 85° C., a load was applied using a constant current method (2 mA) using a constant voltage/constant current DC power supply device [manufactured by Takasago Seisakusho Co., Ltd., GP0650-05R], and the voltage was measured. Plot time on the horizontal axis and voltage on the vertical axis, observe the voltage rise curve over time, and measure the voltage at the moment when the rise curve is first disturbed by sparks or scintillation or the capacitor opens. It was defined as withstand voltage (V).
<Bulging after aging>
A constant voltage/constant current DC power supply [manufactured by Takasago Seisakusho Co., Ltd., GP0650-05R] was used to apply a load using the constant current method (2 mA) at 85°C, aging was performed to 35 V, and the evaluation was performed as follows. went.
〇...No swelling during aging.
△...There is swelling during aging, but the valve does not open.
×...The capacitor opens during aging.
<ESR>
For the hybrid electrolytic capacitor, the ESR value at 100 kHz was measured using an LCR meter (LCR High Tester 3532-50 manufactured by Hioki Electric Co., Ltd.).
The lower the ESR value, the more stable the operation of the capacitor.
<Capacity>
The capacitance of the hybrid electrolytic capacitor at 120 Hz was measured using an LCR meter (LCR High Tester 3532-50 manufactured by Hioki Electric Co., Ltd.).
<Evaluation after high temperature test>
After the hybrid capacitor was left in a constant temperature bath at 125° C. for 500 hours, it was evaluated in the same way as the initial evaluation. The capacitance retention rate was determined by dividing the capacitance after the high temperature test by the initial capacitance and multiplying by 100. The ESR retention rate was determined by dividing the ESR value after the high temperature test by the initial ESR value and multiplying by 100.

A hybrid electrolytic capacitor using the electrolytic solution for a hybrid electrolytic capacitor according to an example of the present invention had good initial characteristics and good results even after a high temperature test.
On the other hand, since Comparative Example 1 does not contain aromatic carboxylic acid (B), the chemical formation property is poor and the pressure increase time is extended, and the opening of the capacitor due to heat generation of the electrolyte, evaporation of electrolyte components, and side reactions occurs. As a result, the withstand voltage became lower. Furthermore, Comparative Example 2 had a small ratio (A/B) and a low withstand voltage. Since Comparative Example 3 does not contain carboxylic acid (A1) or (A2), deterioration of the conductive polymer could not be suppressed, and the ESR increased and the capacitance decreased significantly after the high temperature test. Since Comparative Example 4 did not contain carboxylic acid (A1) or (A2) and aromatic carboxylic acid (B), the ESR increased significantly and the capacitance decreased significantly after the high temperature test.

A hybrid electrolytic capacitor using the electrolytic solution for a hybrid electrolytic capacitor of the present invention suppresses an increase in ESR in a high-temperature environment, so it can be suitably used as a component of electrical products and electronic products that can handle large currents.
The electrolytic solution for a hybrid electrolytic capacitor of the present invention is suitable as an electrolytic solution for a hybrid electrolytic capacitor for mobile applications such as notebook computers that are affected by the outside temperature and tend to reach high temperatures when driven, and particularly for in-vehicle applications.

Claims (4)

At least one member selected from the group consisting of carboxylic acid (A1) represented by general formula (1), carboxylic acid (A2) represented by general formula (2), and carboxylic acid (A3) represented by general formula (3) , and an aromatic carboxylic acid (B) having a molecular weight of 250 or less. ) to the weight (A/B) of 1 to 10,000.

[In formula (1), R ¹ is a residue obtained by removing two hydrogen atoms from a hydrocarbon having 2 to 10 carbon atoms which may have a substituent, or an alkylene group of an oxyalkylene repeating unit having 2 to 10 carbon atoms] It is a residue obtained by removing two hydroxy groups from polyalkylene glycol 6. ]

[In formula (2), R ² is a residue obtained by removing two hydrogen atoms from a hydrocarbon having 2 to 10 carbon atoms which may have a substituent, or an alkylene group of an oxyalkylene repeating unit having 2 to 10 carbon atoms] It is a residue obtained by removing two hydroxy groups from polyalkylene glycol 6. ]

[In formula (3), R ³ is a residue obtained by removing two hydrogen atoms from a hydrocarbon having 2 to 10 carbon atoms which may have a substituent, or an alkylene group of an oxyalkylene repeating unit having 2 to 10 carbon atoms] It is a residue obtained by removing two hydroxy groups from polyalkylene glycol 6. ] The electrolytic solution for a hybrid electrolytic capacitor according to claim 1, wherein the electrolytic solution has a pH of 4 to 6 at 25°C. The electrolytic solution for a hybrid electrolytic capacitor according to claim 1, wherein the water content is 0.05 to 40% by weight based on the weight of the electrolytic solution. A hybrid electrolytic capacitor formed of a capacitor element having an anode foil having a dielectric layer on its surface and a solid electrolyte (C) layer in contact with the dielectric layer of the anode foil, the capacitor element comprising: A hybrid electrolytic capacitor impregnated with the electrolytic solution for a hybrid electrolytic capacitor according to claim 1, wherein the solid electrolyte (C) contains a conductive polymer.