JPH09312243A - Electrolytic solution for drive use for electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the service breakdown voltage of an electrolytic capacitor without damaging the conductivity and moreover,, to make the capacitor stand the wide-range service temperature and to improve the high-temperature life of the capacitor by a method wherein an electrolytic solution, which is formed by dissolving a 3-tertiary butyl hexanoic acid and/or its salts in an organic polar solvent, is used for the electrolytic capacitor. SOLUTION: A 3-tertiary butyl hexanoic acid and/or 1 to 25wt.% of its salts, preferably 3 to 20wt.% of its salts, are dissolved in 99 to 75% of an organic solvent, preferably 97 to 80% of an organic solvent, and an electrolytic solution is prepared. As this result, a change in the specific resistance of an electrolytic capacitor is little at 105 deg.C, the capacitor shows good characteristics and the capacitor can obtain superior electrical characteristics and moreover, the maintenance of the stable characteristics of the capacitor is possible extending over a long period of time even under a high temperature of 105 deg.C.

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 driving an electrolytic capacitor, and more particularly, to an electrolytic solution without impairing electrical conductivity.
It is intended to provide an electrolytic solution for driving an aluminum electrolytic capacitor, which has a high withstand voltage, withstands a wide range of operating temperatures, and has a significantly improved high temperature life.

[0002]

2. Description of the Related Art Conventionally, as a driving electrolytic solution for an aluminum electrolytic capacitor for medium and high voltage, generally, an electrolytic solution prepared by adding boric acid or its salt to ethylene glycol as a main solvent, or adipic acid, azelaic acid and An electrolytic solution containing a linear organic dicarboxylic acid such as sebacic acid or a salt thereof has been used. However, in the former electrolyte, at a high temperature, boric acid reacts with ethylene glycol to produce borodiethylene glycolic acid and a large amount of water. This moisture is
Significantly degrades the aluminum oxide film, which is a dielectric,
Also, at high temperatures, the vapor pressure is high, causing deterioration of electrochemical characteristics such as swelling of the explosion-proof valve and deformation of the outer casing of the capacitor, and shortening the life of the capacitor at high temperatures, especially at 100 ° C or higher. Was causing it.

Further, in the latter electrolytic solution, since the solubility of the linear organic dicarboxylate as a solute in the solvent is low, crystals are easily precipitated at low temperatures, which deteriorates the low-temperature characteristics of the capacitor. I could not escape the shortcomings. Further, at a high temperature, the organic dicarboxylic acid and ethylene glycol react with each other to partially form a carboxylic acid ethylene glycol ester, and the specific resistance deteriorates. Had to be shortened.

[0004]

SUMMARY OF THE INVENTION The present invention is intended to provide a technique capable of solving the drawbacks of the prior art, and particularly to increase the withstand voltage used without impairing the electrical conductivity. Moreover, it is an object of the present invention to provide an electrolytic solution for driving an aluminum electrolytic capacitor which can endure a wide range of use temperatures and has a significantly improved high-temperature life.
The above and other objects and novel characteristics of the present invention are
It will also be clear from the overall description herein.

[0005]

DISCLOSURE OF THE INVENTION The present inventors have prepared 3-tert-butylhexanoic diacid and / or salts thereof having excellent solubility in ethylene glycol and the like by using an organic polar solvent such as ethylene glycol and the like. The capacitor element was impregnated with an electrolytic solution dissolved in the electrolytic solution to obtain an electrolytic solution for an electrolytic capacitor, which did not impair the conductivity, increased the spark generation voltage, improved the product withstand voltage, and was excellent. It has been found that a wide range of temperature characteristics and high-temperature life characteristics can be obtained, and based on this, the present invention has been completed. That is, the present invention contains one or more organic polar solvents and 3-tert-butylbutylhexanedioic acid and / or salts thereof as essential constituents, which will be exemplified later in detail. The present invention relates to an electrolytic solution obtained by dissolving 3-tert-butylbutylhexanedioic acid as an ionogen and / or salts thereof in such a polar solvent.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The 3-tertiarybutylhexanedioic acid used in the present invention is a compound having a structural formula represented by the following formula 1.

[0007]

(Equation 1)

Examples of the organic solvent used in the present invention include polyhydric alcohols such as ethylene glycol, diethylene glycol and glycerin, ether compounds such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether. , N-methylformamide, NN-
One or more amides such as dimethylformamide, nitriles such as acetonitrile and butyronitrile, or cyclic esters such as γ-butyrolactone and valerolactone can be used.

The 3-tertiarybutylhexanedioic acid and / or its salt used in the present invention is used as an electrolyte, has excellent solubility in an organic polar solvent, and is suitable as an ionogen for an electrolytic solution for driving an electrolytic capacitor. Examples of the salts include ammonium salt, ammonium hydrogen salt, amine salt and quaternary ammonium salt.

The amount of the 3-tertiarybutylhexanedioic acid and / or its salts used is 1 to 25% by weight, preferably 3 to 20% by weight. Below this amount, it is difficult to achieve the desired object of the present invention. Further, even if it is more than this, it is also difficult to achieve the object of the present invention.

In a preferred embodiment of the invention, 3
-Tertiarybutylhexanedioic acid and / or its salts 1
-25 wt%, preferably 3-20 wt% organic solvent 99
˜75%, preferably 97 to 80%, and used as an electrolytic solution. At that time, water may be included. When water is included, it is preferably 5% or less.

The electrolytic solution of the present invention may contain various electrolytes conventionally used in this type of electrolytic solution. For example, an electrolyte such as ammonium borate may be used according to the present invention.
It may be used in combination with tert-butyl hexanedioic acid and / or its salts.

[0013]

EXAMPLES The present invention will be described below based on Examples and Comparative Examples.

Examples and Comparative Examples An electrolytic solution was prepared based on the composition shown in Table 1. Specific examples of the composition, specific resistance, and spark generation voltage of the electrolytic solution in Examples of the present invention are shown in Table 1 together with those of the conventional composition examples. Further, an electrolytic solution based on the composition shown in Table 1 was placed in a sealed container, a thermal stability test was performed at 105 ° C., and the results were shown in Table 2. Table 3 shows the results of the electrical characteristics of the capacitor when the electrolytic solution based on the composition shown in Table 1 was impregnated into an electrolytic capacitor element having a rated voltage of 400 V and a capacity of 2.2 μF.

[0015]

[Table 1]

[0016]

[Table 2]

[0017]

[Table 3]

From Table 2, the conventional electrolytic solution is 10 ° C at 105 ° C.
After 00 hours, the specific resistance of the electrolytic solution increased,
The electrolytic solution of the present invention exhibited good characteristics with little change in specific resistance. As shown in Table 3, the conventional electrolytic solution was impregnated with an electrolytic solution to prepare an electrolytic capacitor.
After 000 hours, the appearance was poor or the electrical characteristics were deteriorated. On the other hand, the one prepared by impregnating the electrolytic solution of the present invention to prepare an electrolytic capacitor was 100 ° C at a temperature of 105 ° C.
Despite the elapse of 0 hours, the electrical properties were small and good properties were exhibited, and no poor appearance was observed.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.

[0020]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows. In other words, according to the present invention, it is possible to provide an electrolytic solution for driving an electrolytic capacitor having a higher withstand voltage without impairing the electrical conductivity and significantly improved in a wide range of operating temperature and life characteristics. As shown, the electrolytic solution of the present invention shows good characteristics with little change in the specific resistance value at 105 ° C. Further, the electrolytic capacitor impregnated with the electrolytic solution of the present invention has excellent electric characteristics and can maintain stable characteristics for a long time even at a high temperature of 105 ° C. The significance of contributing to the improvement of the electrical characteristics of the medium- and high-voltage electrolytic capacitors is very significant.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Mitsuru Fukuda 3-11-1 Mizutani Higashi, Fujimi City, Saitama Prefecture Toyama Yakuhin Kogyo Co., Ltd. Shiki Plant

Claims (3)

[Claims] 1. An electrolytic solution for driving an electrolytic capacitor, which comprises 3-tert-butylhexanediacid and / or a salt thereof. 2. The electrolytic capacitor according to claim 1, wherein the salt of 3-tert-butylbutylhexanedioic acid is an ammonium salt or amine salt of 3-tert-butylhexanedioic acid. Drive electrolyte. 3. The electrolytic capacitor according to claim 1 or 2, wherein the concentration of 3-tert-butylhexanediacid and / or its salt in the electrolytic solution is 1 to 25% by weight. Electrolyte for driving.