JPH11176700A - Aluminium electrolytic capacitor and electrolytic soln. for driving the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress reduction of electrolyte conductivity and raises spark voltage by adding a swelling F mica grain in a specified grain size range to an electrolyte composed of a solvent and salute. SOLUTION: A swelling F mica grain in a grain size range of 1 nm-10 μm is added to an electrolyte composed of a non-protic solvent such as β- or γ- butyloluctone and γ-valeroluctone, or protic solvent such as ethylene glycol, ethylene glycol monoalkylether and ethylene glycol dialkylether, and a solute of aromatic carboxylic acid such as phthalic acid, benzoic acid, salicylic acid and resorcylic acid, aliphatic carboxylic acid such as maleic acid, citraconic acid and fumaric acid. This suppresses the reduction of the electrolyte conductivity and raises the spark voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art An aluminum electrolytic capacitor is an electrolytic capacitor formed by winding an aluminum anode foil having an oxide film formed on the surface of an etched aluminum foil by electrolytic oxidation or the like and an etched aluminum cathode foil through a separator. The capacitor driving electrolyte is impregnated, placed in a bottomed metal case, the opening is sealed with an insulating sealing body, and the lead leads fixed to the anode foil and the cathode foil are respectively sealed. Has a structure drawn out from the through hole.

In order to increase the spark voltage of an aluminum electrolytic capacitor (hereinafter referred to as "electrolytic capacitor"),
Driving electrolyte (hereinafter referred to as “electrolyte”) has a great relationship, and therefore, an electrolyte composed of a solvent and a solute includes an inorganic acid such as boric acid, phosphoric acid, tungstic acid, and a heteropoly acid or a salt thereof, mannite, Polysaccharides such as sorbitol, silicone oil, polyvinyl chloride, or a mixture thereof were added.

[0004]

However, according to these methods, various characteristics (capacitance, ta) of the electrolytic capacitor are required.
It was not always possible to sufficiently improve the spark voltage without adversely affecting nδ, leakage current, etc.).

Accordingly, silica colloid particles (Japanese Patent Laid-Open No.
No. 8512), zirconium dioxide (Japanese Unexamined Patent Publication No.
No. 45613), antimony pentoxide (Japanese Unexamined Patent Publication No.
No. 45614), tantalum pentoxide (Japanese Unexamined Patent Publication No.
No. 3615), titanium dioxide (Japanese Unexamined Patent Publication No.
No. 16) has also been proposed, but it has been desired to further prevent a decrease in electric conductivity when improving the spark voltage.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned problems, and has an object to drive an aluminum electrolytic capacitor for driving a medium- and high-voltage aluminum electrolytic capacitor having a high sparking voltage, high conductivity, and excellent characteristics. An electrolyte is provided. That is, the present invention is characterized in that swellable fluoromica particles are added to an electrolytic solution comprising a solvent and a solute.

[0007] The swellable fluorine mica particles may be natural or synthetic, but those synthesized from the viewpoint of a small amount of impurities are preferred. The average particle size is preferably in the range of 1 nm to 10 μm. Swellable fluoromica particles having an average particle size of 1 nm to 10 μm can be obtained industrially at low cost.

The addition amount of the swellable fluoromica particles is 0.05
If the amount is less than 0.05% by weight, the effect of increasing the spark voltage is small, and if the amount exceeds 20% by weight, there is a risk that the electrolytic solution solidifies.

As the solute, an ammonium salt or an amine salt of an organic acid or an inorganic acid is preferred, and preferred organic acids are aromatic carboxylic acids such as phthalic acid, benzoic acid, salicylic acid or resorcylic acid, maleic acid, citraconic acid, and the like. Aliphatic carboxylic acids such as fumaric acid, malonic acid and nonanoic acid are preferred, but not limited thereto.

Examples of the inorganic acid include, but are not limited to, boric acid, phosphoric acid, and silicic acid.

The electrolytic solution of the present invention preferably uses an aprotic solvent or a protic solvent alone or as a mixture as a solvent. As the aprotic solvent, β-butyrolactone, γ-butyrolactone, γ-valerolactone, δ-valerolactone Γ-caprolactone, ε-caprolactone, γ-heptalactone, γ-hydroxy-n-caprylic acid lactone, γ-nonalactone, δ-decalactone,
Lactones such as γ-undecalactone are preferred,
It is not limited only to lactones.

In the present invention, when a protic solvent is used, glycols are preferred. Ethylene glycol, ethylene glycol monoalkyl ether, ethylene glycol dialkyl ether, propylene glycol, diethylene glycol, diethylene glycol monoalkyl ether, diethylene glycol dialkyl ether , Polyethylene glycol, glycerin and the like are preferred, but not limited to glycols alone.

In the electrolytic solution according to the present invention, the content of the solute in the solvent can be variously selected, but the state of a saturated solution is most preferable because it has the highest electric conductivity. That is, the solute content is 1 to 60% by weight, preferably 10 to 10% by weight in the electrolytic solution.
It is about 40% by weight, and if it exceeds 60% by weight, it will not be dissolved.

In the present invention, when a mixture of lactones and glycols is used, the mixing ratio of lactones and glycols is about 20:80 to 95: 5 by weight.

The tangent (t) of the initial loss angle of the electrolytic capacitor
In order to improve an δ), a ketone, a nitro compound or a salt thereof may be added to the electrolyte solution according to the present invention in an amount of 0.1 to 10% by weight, preferably 0.1 to 5% by weight.

The pH of the electrolytic solution according to the present invention is adjusted to 4 to 12, preferably 4 to 10, by adding a desired pH adjuster as required. Further, the presence of water in the electrolytic solution at high temperatures causes corrosion of the aluminum foil. Therefore, it is desirable that the water is not present as much as possible. However, if it is about 4% by weight or less, no particular inconvenience occurs.

[0017]

EXAMPLES Examples 1 and 2 have the following compositions.
2 was prepared, and the following comparative examples 1 and 2 were prepared as comparative examples. The swellable fluoromica particles added to Examples 1 and 2 are “Somasif” manufactured by Corp Chemical Co., Ltd. The pH was 7.4 in Example 1 and Comparative Example 1, and 6.9 in Example 2 and Comparative Example 2.

Example 1 Triethylammonium phthalate 17% by weight γ-butyrolactone 64% by weight Ethylene glycol 15% by weight Water 2% by weight Swellable fluoromica particles 2% by weight

Example 2 Ammonium 1,9 nonanedicarboxylate 13% by weight Boric acid 2% by weight Mannit 3% by weight Ethylene glycol 75% by weight Water 3% by weight Swellable fluoromica particles 4% by weight

Comparative Example 1 Triethylammonium phthalate 17.8% by weight γ-butyrolactone 64.5% by weight Ethylene glycol 15.7% by weight Water 2.0% by weight

Comparative Example 2 Ammonium 1,9 nonanedicarboxylate 13.5% by weight Boric acid 2.5% by weight Mannit 3.5% by weight Ethylene glycol 77.5% by weight Water 3.0% by weight

The electric conductivity (μS / cm; at a liquid temperature of 40 ° C.) and the spark voltage (V; at a liquid temperature of 105 ° C.) of the electrolyte solutions of Examples 1 and 2 and Comparative Examples 1 and 2 were measured. Table 1 shows the results.

[0023]

[Table 1]

From this result, it can be seen that the electrolyte of Example 1 has a significantly higher spark voltage than the electrolyte of Comparative Example 1. Furthermore, it can be seen that the electrolyte of Example 2 has a significantly higher spark voltage than the electrolyte of Comparative Example 2.

Next, using the electrolyte of Example 1 and the electrolyte of Comparative Example 1, 10 JIS04 type electrolytic capacitors rated at 100 V and 680 μF (product size; diameter: 18 mm, shaft length: 40 mm) were manufactured, and the capacitor performance was measured. (Capacitance C
(ΜF), tan δ, leakage current LC (μA / 1mi
n)) was measured. Table 2 shows the average value.

[0026]

[Table 2]

Also, using the electrolyte solution of Example 2 and the electrolyte solution of Comparative Example 2, ten JIS04 type electrolytic capacitors rated at 450 V and 120 μF (product size; diameter: 18 mm, shaft length: 40 mm) were manufactured, and the performance of the capacitors was measured. (Capacitance C (μF), tan δ, leakage current LC (μA / 1mi
n)) was measured. Table 3 shows the average value.

[0028]

[Table 3]

Since the electrolytic capacitors of Comparative Examples 1 and 2 had insufficient withstand voltage, all of them could not be commercialized due to the operation of the safety valve provided at the bottom of the metal case during aging. Therefore, the electrolytic capacitors of Examples 1 and 2 have improved withstand voltage and can be commercialized, and the addition of swellable fluorine mica particles does not adversely affect various properties such as capacitance, tan δ, and leakage current. I understand.

[0030]

According to the present invention, it is possible to improve the spark voltage while minimizing the decrease in the conductivity of the electrolyte,
In addition, the withstand voltage can be improved without adversely affecting various characteristics such as the capacitance, tan δ, and leakage current of the electrolytic capacitor.

Claims (4)

[Claims] 1. An electrolytic solution for driving an aluminum electrolytic capacitor, comprising swellable fluorine mica particles added to an electrolytic solution comprising a solvent and a solute. 2. The particle size of the swellable fluorine mica particles is from 1 nm to 1 nm.
2. The electrolytic solution for driving an aluminum electrolytic capacitor according to claim 1, which has a range of 0 μm. 3. An aluminum electrolytic capacitor characterized by using an electrolytic solution for driving an aluminum electrolytic capacitor obtained by adding swellable fluorine mica particles to an electrolytic solution comprising a solvent and a solute. 4. The swellable fluorine mica particles having a particle size of 1 nm to 1 nm.
The aluminum electrolytic capacitor according to claim 3, wherein an electrolytic solution for driving an aluminum electrolytic capacitor having a range of 0 µm is used.