JPH11214268A - Electrolyte solution for aluminum electrolytic capacitor and aluminum electrolytic capacitor using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deposition of a crystallized substance containing hydroxybutyric acid as a principal component to a contact interface between a lead hole of a sealing rubber and a cathode-side lead wire, in the case where an aluminum electrolytic capacitor using an electrolyte solution formed by dissolving an electrolyte into a solvent containing γ-butyrolactone is used for a long period of time at a high temperature and high humidity, and thus provide an aluminum electrolytic capacitor of high reliability. SOLUTION: In an electrolyte solution for an aluminum electrolytic capacitor formed by dissolving a salt of organic acid and a base of 1.0×10<-10> mol/dm<3> or less when the concentration of hydrogen ions in the base or a solution of hydroxide of the base is 1 wt.% and the measured temperature is 30 deg.C from among nitrogen-containing bases as an electrolyte into a solvent containing γ-butyrolactone, one or more selected from the group consisting of o-nitrobenzoic acid, m-nitrobenzoic acid, o-nitrophenol, and p-nitrophenol is dissolved within a range of 0.1-5 wt.%. Thus, an aluminum electrolytic capacitor of high reliability is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic solution for an aluminum electrolytic capacitor used for an aluminum electrolytic capacitor and an aluminum electrolytic capacitor using the same.

[0002]

2. Description of the Related Art Conventionally, as an electrolytic solution for an aluminum electrolytic capacitor, a solution obtained by dissolving an organic acid, an inorganic acid or a salt thereof in γ-butyrolactone having a low viscosity at a low temperature as an electrolyte has been used. An electrolytic solution for an aluminum electrolytic capacitor using a diethylamine salt as an electrolyte (JP-A-54-1024) is known.

Further, an electrolytic solution for aluminum electrolytic capacitors using a quaternary ammonium salt of maleic acid or citraconic acid as an electrolyte (Japanese Patent Publication No. 3-6646), or a quaternary ammonium salt of an aromatic carboxylic acid as an electrolyte Electrolyte for aluminum electrolytic capacitors (Japanese Patent Publication No. 3-8092) and a carboxylate of a compound having an alkyl-substituted amidine group and a quaternary compound of an alkyl-substituted amidine group as an electrolyte. Liquid (republished patent gazette, international publication number WO95 / 1557)
No. 2), so-called amidine-based electrolytes and the like are known.

When these electrolytic solutions for aluminum electrolytic capacitors are used in aluminum electrolytic capacitors, the generation of hydrogen gas on the cathode side caused by an electrochemical reaction inside the aluminum electrolytic capacitors is reduced, and the appearance of the aluminum electrolytic capacitors is reduced. It has been proposed to add various nitro compounds for the purpose of reducing the valve opening rate during blistering, aging and long-term use.

[0005]

However, many nitro compounds proposed for the purpose of reducing the generation of hydrogen gas in the conventional electrolytic solution for aluminum electrolytic capacitors include hydrogen ions in an aqueous solution of a base or a hydroxide of a base. Concentration is 1% by weight of base or aqueous solution of base
1.0 × 10 ⁻¹⁰ when the measurement temperature is 30 ° C.
When a salt of a highly basic base and an organic acid having a mol / dm ³ or less is used as an electrolyte in a solvent containing γ-butyrolactone as an electrolyte, a hydrogen gas generation reaction on the cathode side and Since it has the action of crystallizing hydroxybutyric acid generated by the decomposition reaction of coexisting γ-butyrolactone, when an aluminum electrolytic capacitor is used for a long time under high temperature and high humidity, the contact interface between the lead hole of the sealing rubber and the cathode side lead wire may be formed. Crystals containing hydroxybutyric acid as a main component may be deposited, thereby deteriorating the sealing property.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem, and the hydrogen ion concentration in an aqueous solution of a base or a hydroxide of a base among nitrogen-containing bases is reduced. When the concentration of the aqueous solution is 1% by weight and the measurement temperature is 30 ° C., a salt of a base and an organic acid having a concentration of 1.0 × 10 ⁻¹⁰ mol / dm ³ or less is used as an electrolyte in a solvent containing γ-butyrolactone. In the dissolved electrolytic solution for an aluminum electrolytic capacitor, at least one selected from the group consisting of o-nitrobenzoic acid, m-nitrobenzoic acid, o-nitrophenol, and p-nitrophenol is contained in an amount of 0.1 to 5% by weight. An electrolytic solution for an aluminum electrolytic capacitor having a dissolved configuration is used, and this electrolytic solution is used for an aluminum electrolytic capacitor.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention is characterized in that the hydrogen ion concentration in an aqueous solution of a base or a hydroxide of a base among nitrogen-containing bases is 1% by weight. And the measurement temperature is 30 ° C.,
In an electrolytic solution for an aluminum electrolytic capacitor, a salt of a base and an organic acid having a concentration of 1.0 × 10 ⁻¹⁰ mol / dm ³ or less is dissolved as an electrolyte in a solvent containing γ-butyrolactone.
1 selected from the group consisting of o-nitrobenzoic acid, m-nitrobenzoic acid, o-nitrophenol and p-nitrophenol
It is an electrolytic solution for an aluminum electrolytic capacitor having a composition in which at least one species is dissolved in a range of 0.1 to 5% by weight. Even when hydroxybutyric acid is generated by a chemical change of γ-butyrolactone as a solvent on the cathode side, Crystals containing hydroxybutyric acid as a main component cannot be generated because the nuclei required for crystal growth are not generated, and even when the aluminum electrolytic capacitor is used for a long time under high temperature and high humidity, the lead hole of the sealing rubber and the cathode side lead are used. It has an effect that crystals containing hydroxybutyric acid as a main component are not deposited on the contact interface with the wire, and the sealing property is not reduced.

According to a second aspect of the present invention, in the first aspect, the hydrogen ion concentration in the aqueous solution of the base or the hydroxide of the base among the nitrogen-containing bases is 1 or less. % By weight and the measurement temperature is 3
At 0 ° C., quaternary ammonium is used as a base having a concentration of 1.0 × 10 ⁻¹⁰ mol / dm ³ or less,
The combination with the nitro compound has an effect that an electrolytic solution for an aluminum electrolytic capacitor having high heat resistance can be formed.

According to a third aspect of the present invention, in the second aspect, a tetraalkylammonium is used as the quaternary ammonium, and the tetraalkylammonium is one of the quaternary ammoniums. Since it has high heat resistance, it has an effect that an electrolytic solution for an aluminum electrolytic capacitor having higher heat resistance can be formed in combination with the nitro compound.

According to a fourth aspect of the present invention, in the first aspect, the hydrogen ion concentration of the nitrogen-containing base in the aqueous solution of the base or the hydroxide of the base is 1 or less. % By weight and the measurement temperature is 3
At 0 ° C., a composition having an alkyl-substituted amidine group as a base having a base of 1.0 × 10 ⁻¹⁰ mol / dm ³ or less is used, and an electrolytic solution for an aluminum electrolytic capacitor having a small capacity change rate is used. It has the effect that it can be configured.

[0011] The invention according to claim 5 is the invention according to claim 4, wherein the compound having an alkyl-substituted amidine group is an imidazole compound, a benzimidazole compound,
An alicyclic amidine compound (pyrimidine compound, imidazoline compound) is a composition using at least one selected from the group consisting of an imidazole compound, a benzimidazole compound, an alicyclic amidine compound (pyrimidine compound,
Since the imidazoline compound) has a small capacity change rate among the compounds having an alkyl-substituted amidine group, it has an effect that an electrolytic solution for an aluminum electrolytic capacitor having a smaller capacity change rate can be formed.

According to a sixth aspect of the present invention, in the first aspect, the hydrogen ion concentration of the nitrogen-containing base in the aqueous solution of the base or the hydroxide of the base is 1 or less. % By weight and the measurement temperature is 3
At 0 ° C., a quaternary product of a compound having an alkyl-substituted amidine group in a base of 1.0 × 10 ⁻¹⁰ mol / dm ³ or less is used. In combination with the nitro compound, This has the effect that an electrolyte for an aluminum electrolytic capacitor having excellent resistance to leakage under high temperature and high humidity can be formed.

The invention according to claim 7 is the invention according to claim 6, wherein the quaternized compound having an alkyl-substituted amidine group is an imidazole compound, a benzimidazole compound, an alicyclic amidine compound (a pyrimidine compound,
And a quaternary compound of an imidazole compound, a benzimidazole compound, and an alicyclic amidine compound (pyrimidine compound, imidazoline compound). Is a quaternized compound having an alkyl-substituted amidine group, which is excellent in liquid leakage resistance under high temperature and high humidity. Therefore, in combination with the above nitro compound, aluminum electrolytic solution is excellent in liquid leakage resistance under high temperature and high humidity. It has an effect that an electrolytic solution for a capacitor can be formed.

According to an eighth aspect of the present invention, there is provided an aluminum electrolytic capacitor using the electrolytic solution for an aluminum electrolytic capacitor according to any one of the first to seventh aspects. Even when hydroxybutyric acid is generated due to the chemical change of butyrolactone, the nucleus necessary for crystal growth is not generated, so crystals containing hydroxybutyric acid as a main component cannot be generated, and aluminum electrolytic capacitors are used for a long time under high temperature and high humidity. In this case, no crystals mainly composed of hydroxybutyric acid are deposited at the contact interface between the lead hole of the sealing rubber and the cathode-side lead wire, and the sealing property is not reduced. It has the effect that a high aluminum electrolytic capacitor can be constructed.

Hereinafter, an embodiment of the present invention will be described. In the electrolyte of the electrolytic solution for an aluminum electrolytic capacitor of the present invention, the molar ratio of the base and the organic acid in the solvent containing γ-butyrolactone is not particularly limited, but the high conductivity and the degradability of γ-butyrolactone (hydroxy The ratio of base: organic acid = 1.0: 0.9 to 1.0: 3.0 is preferable in consideration of the small amount of butyric acid.

Examples of the organic acid used in the electrolytic solution for an aluminum electrolytic capacitor of the present invention include polycarboxylic acids (2 to 2).
Tetravalent): aliphatic polycarboxylic acid [saturated polycarboxylic acid,
For example, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,6-decanedicarboxylic acid, 5,6-decanedicarboxylic acid: unsaturated polycarboxylic acid, For example, maleic acid, fumaric acid, icotanic acid]; aromatic polycarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, and pyromellitic acid; alicyclic polycarboxylic acids such as tetrahydrophthalic acid (cyclohexane-
1,2-dicarboxylic acid, etc.), hexahydrophthalic acid; alkyl (1 to 3 carbon atoms) or nitro-substituted polycarboxylic acids such as citraconic acid, dimethylmaleic acid, nitrophthalic acid (3-nitrophthalic acid, 4 And sulfur-containing polycarboxylic acids such as thiopropionic acid; monocarboxylic acids; aliphatic monocarboxylic acids (1 to 30 carbon atoms) [saturated monocarboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid). Butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, lauric acid, myristic acid, stearic acid, behenic acid: unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, oleic acid]; aromatic monocarboxylic acids Acids such as benzoic acid, o-nitrobenzoic acid, p-nitrobenzoic acid,
Cinnamic acid, naphthoic acid; oxycarboxylic acids such as salicylic acid, mandelic acid and resorcinic acid, of which phthalic acid, maleic acid and adipic acid having high conductivity and being thermally stable are preferred. Benzoic acid.

Examples of the quaternary ammonium used in the electrolytic solution for an aluminum electrolytic capacitor of the present invention include tetraalkylammoniums [tetramethylammonium, trimethylethylammonium, dimethyldiethylammonium, methyltriethylammonium, tetraethylammonium, trimethyln -Propyl ammonium,
Trimethyl isopropyl ammonium, dimethyl ethyl n-propyl ammonium, dimethyl ethyl isopropyl ammonium, methyl diethyl n-propyl ammonium, methyl diethyl isopropyl ammonium, triethyl isopropyl ammonium, triethyl n-propyl ammonium, tetra n-propyl ammonium,
Tetraisopropylammonium, tetran-butylammonium, tetratert-butylammonium, etc.] and phenyltrialkylammonium [trimethylphenylammonium, dimethylethylphenylammonium, triethylphenylammonium, etc.]. Tetraalkylammonium, and more preferably, at least one selected from the group consisting of tetramethylammonium, trimethylethylammonium, dimethyldiethylammonium, methyltriethylammonium, and tetraethylammonium having high heat resistance.

The alkyl-substituted amidine group-containing compound 4 used in the electrolytic solution for an aluminum electrolytic capacitor of the present invention
Examples of the graded compound include an imidazole compound, a benzimidazole compound, and an alicyclic amidine compound (pyrimidine compound, imidazoline compound) quaternized with an alkyl group or an arylalkyl group having 1 to 11 carbon atoms. Has excellent resistance to liquid leakage under high temperature and high humidity.
-Methyl-1,8-diazabicyclo [5,4,0] undecene-7, 1-methyl-1,5-diazabicyclo [4,3,0] nonene-5,1,2,3-trimethylimidazolinium, 1,2,3,4-tetramethylimidazolinium, 1,2-dimethyl-3-ethyl-imidazolinium, 1,3,4-trimethyl-2-ethylimidazolinium, 1,3-dimethyl-2 -Heptyl imidazolinium, 1,3-dimethyl-2- (3'heptyl) imidazolinium, 1,3-dimethyl-2-dodecyl imidazolinium, 1,2,3-trimethyl-1,4,5
6-tetrahydropyrimidium, 1,3-dimethylimidazolium, 1,3-dimethylbenzimidazolium are preferred, and more preferably, conductivity is high among them.
1,2,3,4-tetramethylimidazolinium is the most thermally stable.

In the electrolytic solution for an aluminum electrolytic capacitor of the present invention, the pH of the electrolytic solution is generally 4 to 8, preferably 5 to 7.
Outside this range, the spark voltage of the electrolyte decreases.

The solvent used for the electrolytic solution for an aluminum electrolytic capacitor of the present invention may contain another organic solvent as a component other than γ-butyrolactone. Examples of the organic solvent mixed with γ-butyrolactone include alcohols [Monohydric alcohols (butyl alcohol, diacetone alcohol, benzyl alcohol, amino alcohol, etc.); dihydric alcohols (ethylene glycol, propylene glycol, diethylene glycol, hexylene glycol, phenyl glycol, etc.); trihydric alcohols (glycerin, 3- Hexitol, etc.], ethers [monoethers (ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether) , Ethylene glycol monophenyl ether, etc.); diethers (ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, etc.), amides [formamides (N-methylformamide, N,
Acetamides (N-methylacetamide, N, N-dimethylacetamide, N-ethylacetamide, N, N, -diethylacetamide, etc.); propionamides (N, N-dimethylacetamide, N, N-dimethylacetamide, N, N-diethylacetamide, etc.); N, -dimethylpropionamide, etc.); hexamethylphosphorylamide, etc.], oxazolidinones (1,3-dimethyl-2-imidazolidinone, 3-methyloxazolidin-2-one, etc.), carbonates (propylene carbonate, ethylene carbonate) Dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, etc.), dimethyl sulfoxide, and a mixture of two or more thereof.

In the case of a mixed solvent, the content of γ-butyrolactone is preferably from 50 to 100% by weight based on the weight of the solvent, and if the content of γ-butyrolactone is less than 50%, the conductivity is remarkably reduced.

The electrolytic solution for an aluminum electrolytic capacitor of the present invention may contain water if necessary, and its content is less than 10% based on the weight of the electrolytic solution. When the content of water is 10% or more, hydrogen gas generation becomes large. Therefore, even if the nitro compound of the present invention is used, the hydrogen gas generation reaction cannot be completely suppressed, and the case valve may open to impair the capacitor performance. is there. When the water content is 10% or more,
Since the chemical conversion of γ-butyrolactone into hydroxybutyric acid is also promoted, crystals containing hydroxybutyric acid as a main component are likely to be generated, which is not preferable.

If necessary, various additives may be mixed in the electrolytic solution for an aluminum electrolytic capacitor of the present invention. Examples of the additives include phosphorus compounds [phosphoric acid, phosphoric acid ester, etc.], boric acid compounds [boric acid, complex compounds of boric acid and polysaccharides (mannitol, sorbite, etc.), boric acid and polyhydric alcohols. (Ethylene glycol, glycerin, etc.)]. Mixing a phosphorus-based compound with the electrolytic solution for an aluminum electrolytic capacitor of the present invention is preferable because hydration deterioration of aluminum as the electrode foil can be suppressed. Mixing a boric acid-based compound or a complex compound of boric acid and a polyhydric alcohol with the electrolytic solution for an aluminum electrolytic capacitor of the present invention is preferable because the chemical performance of the electrode foil can be improved.

The content of the electrolyte salt in the electrolytic solution for an aluminum electrolytic capacitor of the present invention is usually 5 to 50% by weight, preferably 10 to 30% by weight based on the weight of the electrolytic solution. If it is less than this range, the electrical conductivity is remarkably reduced, and if it exceeds this range, the components (electrolyte salt and stoichiometrically excessive carboxylic acid and carboxylate anion) in the electrolyte are precipitated at a low temperature, which is not preferable.

Next, specific examples of the present invention will be described, but the present invention is not limited thereto. Hereinafter, all parts are by weight.

Table 1 shows the composition and conductivity of the electrolytic solution of Embodiments 1 to 10 of the present invention and Comparative Examples 1 to 5, and a measure of the hydrogen ion concentration in the aqueous solution of the base or the hydroxide of the base. Base or aqueous solution concentration of base is 1% by weight
And when the measurement temperature is 30 ° C. (pH = −1
og [hydrogen ion concentration], pH> 10
Range, the hydrogen ion concentration is 1.0 × 10 ⁻¹⁰ mol / d
shows the mean) that m ³ or less.

[0027]

[Table 1]

The electrolytic solutions for aluminum electrolytic capacitors according to Embodiments 1 to 10 of the present invention and Comparative Examples 1 to 5 were respectively placed in an H-shaped glass cell in which an anode chamber and a cathode chamber were separated by a glass partition (G4). At a constant current, and the presence or absence of a crystal mainly composed of hydroxybutyric acid generated on the cathode electrode after the electrolysis was observed. The amount of electrolyte used for electrolysis was 2
0 ml (10 ml for the anode chamber side and 10 ml for the cathode chamber side), and a platinum plate having an area of 5 cm ² and a thickness of 0.2 mm was used for both the anode and the cathode as electrode materials. The amount of electricity passed during the electrolysis was controlled by the duration (200 minutes) and the current value (30 mA). The state on the cathode electrode after the electrolysis is shown in (Table 2).

[0029]

[Table 2]

In Comparative Examples 1 to 3, since p-nitrobenzoic acid is used as the nitro compound, crystal nuclei are generated during the electrolysis. Generate on top. Further, in Comparative Example 4, although p-nitrobenzoic acid was used, a relatively weak base and a salt of an organic acid were used for the electrolyte, so that no crystal was formed. As can be seen from Table 1), the conductivity is lowered, and the impedance of the aluminum electrolytic capacitor is increased. (Table 2)
As is clear from the above, in the electrolytic solution for an aluminum electrolytic capacitor according to Embodiments 1 to 10 of the present invention, since a crystal nucleation substance is not generated during electrolysis, even when hydroxybutyric acid is generated, hydroxybutyric acid is used as a main component. It can be seen that no crystalline material is produced.

Next, a winding type aluminum electrolytic capacitor (with a rated voltage of 35 V-electrostatic capacitor) using the electrolytic solution for an aluminum electrolytic capacitor of Embodiments 1 to 10 of the present invention and Comparative Examples 1 to 3 and Comparative Example 5 was used. Capacity 2200μF, size; φ
16 mm x L35 mm). Aluminum having a purity of 99.9% was used for both electrodes of the lead-out lead, and peroxide-cured butyl rubber was used for the sealing rubber. A reverse voltage of -2.0 V is applied to this aluminum electrolytic capacitor, and a temperature of 85 ° C. and a relative humidity of 85% RH is applied for 1000 hours in a thermostat.
After deterioration, disassemble the capacitor and observe the state of the contact interface between the lead hole of the sealing rubber and the negative potential side lead wire (the lead wire on the anode side because a reverse voltage is applied) and swelling of the capacitor case The amount was measured. The results are shown in Table 3 together.

[0032]

[Table 3]

As is clear from Table 3, the electrolytic solutions for aluminum electrolytic capacitors according to Embodiments 1 to 10 of the present invention are as follows.
Even after the lapse of 1000 hours, no deposition of crystals containing hydroxybutyric acid as a main component was observed at the contact interface between the lead hole of the sealing rubber and the cathode-side lead wire, and liquid leakage due to impaired sealing property was also observed. Was not done. In addition, since it also has the effect of reducing hydrogen gas generation, the amount of swelling of the capacitor case is small. On the other hand, in Comparative Example 5 using an electrolytic solution for an aluminum electrolytic capacitor to which no nitro compound was added,
It can be seen that the amount of swelling of the capacitor case is large because the generation of hydrogen gas is large.

Therefore, a highly reliable aluminum electrolytic capacitor can be formed by using the electrolytic solution for an aluminum electrolytic capacitor of the present invention.

In the case of nitro compounds other than the above four types of nitro compounds, crystals easily grow when hydroxybutyric acid is generated due to the generation of crystal nuclei due to a chemical change of the nitro group. When used for a long time under high humidity, crystals mainly composed of hydroxybutyric acid are deposited on the contact interface between the lead hole of the sealing rubber and the lead wire on the cathode side, which is not preferable because the sealing property tends to be reduced.

The amount of the nitro compound dissolved is 0.1% by weight.
If it is less than the above range, the effect of reducing the generation of hydrogen gas, which is the original function, is not sufficient, so that the appearance of the capacitor is undesirably expanded. If the amount of the nitro compound dissolved exceeds 5% by weight, the occurrence of short circuits during aging is undesirably large.

When the concentration of hydrogen ions in the aqueous solution of the base or the hydroxide of the base is 1% by weight and the measurement temperature is 30 ° C.,
In a salt of a relatively weakly basic base and an organic acid (for example, triethylamine hydrogen phthalate) exceeding 0 × 10 ⁻¹⁰ mol / dm ³ , hydroxybutyric acid is hardly generated, and thus the nitro compound of the present invention is not used. Regardless of the compound, a crystal containing hydroxybutyric acid as a main component is not generated, and therefore, there is no effect of the configuration of the present invention (however, a relatively weakly basic salt of a base and an organic acid has low conductivity, This is not preferable because the impedance of the aluminum electrolytic capacitor increases.)

[0038]

As described above, according to the present invention, the concentration of hydrogen ions in an aqueous solution of a base or a hydroxide of a base among nitrogen-containing bases is 1% by weight and the measurement temperature is 1% by weight. At 30 ° C., an electrolytic solution for an aluminum electrolytic capacitor in which a salt of a base and an organic acid having a concentration of 1.0 × 10 ⁻¹⁰ mol / dm ³ or less is dissolved as an electrolyte in a solvent containing γ-butyrolactone. Nitrobenzoic acid, m-nitrobenzoic acid, o-nitrophenol, p-
At least one selected from the group consisting of nitrophenol
By using the electrolytic solution for aluminum electrolytic capacitor dissolved in the range of 5% by weight for the aluminum electrolytic capacitor, even when hydroxybutyric acid is generated due to chemical change of the solvent γ-butyrolactone on the cathode side, it is necessary for crystal growth. Crystals containing hydroxybutyric acid as a main component cannot be formed because no nuclei are formed, and even when the aluminum electrolytic capacitor is used for a long time under high temperature and high humidity, the contact interface between the lead hole of the sealing rubber and the cathode side lead wire Since a crystal having hydroxybutyric acid as a main component is not deposited and the sealing property is not deteriorated, a highly reliable aluminum electrolytic capacitor can be provided.

Claims (8)

[Claims] 1. Among the nitrogen-containing bases, the hydrogen ion concentration in the aqueous solution of the base or the hydroxide of the base is 1% by weight, and the measurement temperature is 3%.
At 0 ° C., an electrolytic solution for an aluminum electrolytic capacitor obtained by dissolving a salt of a base and an organic acid having a concentration of 1.0 × 10 ⁻¹⁰ mol / dm ³ or less as an electrolyte in a solvent containing γ-butyrolactone at 0 ° C. Nitrobenzoic acid, m-nitrobenzoic acid,
An electrolytic solution for an aluminum electrolytic capacitor in which at least one selected from the group consisting of o-nitrophenol and p-nitrophenol is dissolved in a range of 0.1 to 5% by weight. 2. The hydrogen ion concentration in an aqueous solution of a base or a hydroxide of a base is 1.0 × when the concentration of an aqueous solution of a base or a base is 1% by weight and the measurement temperature is 30 ° C.
2. The electrolytic solution for an aluminum electrolytic capacitor according to claim 1, wherein the base having a content of 10 ^-10 mol / dm ³ or less is a quaternary ammonium. 3. The electrolytic solution for an aluminum electrolytic capacitor according to claim 2, wherein the quaternary ammonium is a tetraalkylammonium. 4. When the concentration of hydrogen ions in an aqueous solution of a base or a hydroxide of a base is 1% by weight and the measuring temperature is 30 ° C., the hydrogen ion concentration is 1.0 ×
2. The electrolytic solution for an aluminum electrolytic capacitor according to claim 1, wherein the base having 10 ^-10 mol / dm ³ or less is a compound having an alkyl-substituted amidine group. 5. The aluminum electrolyte according to claim 4, wherein the compound having an alkyl-substituted amidine group is at least one selected from the group consisting of an imidazole compound, a benzimidazole compound, and an alicyclic amidine compound (pyrimidine compound, imidazoline compound). Electrolyte for capacitors. 6. The hydrogen ion concentration in the aqueous solution of the base or the hydroxide of the base is 1.0 × when the concentration of the aqueous solution of the base or the base is 1% by weight and the measurement temperature is 30 ° C.
2. The electrolytic solution for an aluminum electrolytic capacitor according to claim 1, wherein the base having 10 ^-10 mol / dm ³ or less is a quaternary compound of a compound having an alkyl-substituted amidine group. 7. The quaternized product of the compound having an alkyl-substituted amidine group is at least one quaternized product selected from the group consisting of an imidazole compound, a benzimidazole compound, and an alicyclic amidine compound (pyrimidine compound, imidazoline compound). The electrolytic solution for an aluminum electrolytic capacitor according to claim 6. 8. A hydrogen ion concentration in an aqueous solution of a base or a hydroxide of a base among nitrogen-containing bases, the concentration of the base or the aqueous solution of the base is 1% by weight, and the measurement temperature is 30%.
The composition according to any one of claims 1 to 7, wherein a salt of a base and an organic acid having a concentration of 1.0 × 10 ^-10 mol / dm ³ or less at a temperature of ° C is dissolved as an electrolyte in a solvent containing γ-butyrolactone. An aluminum electrolytic capacitor using the electrolytic solution for an aluminum electrolytic capacitor described.