JPH0590079A - Electrolytic capacitor driving electrolyte - Google Patents

Abstract

PURPOSE:To obtain an electrolyte which lowers the impedance of an electrolytic capacitor and lengthens the life thereof by dissolving tetraalkylammonium or tetraalkylphosphonium salt of benzene-1, 2, 4, 5,-carboxylic acid in a solution as principal solvent containing gamma-butyrolactone. CONSTITUTION:Tetraalkylammonium or tetraalkylphosphonium salt of benzene-1, 2, 4, 5,-tetracarboxylic acid is dissolved in a solution whose principal solvent is gamma-butyrolactone, an electrolytic capacitor driving electrolyte being obtained. In that time 5 to 30 g of tetraalkylammonium or tetraalkyl-phosphonium salt of benzene-1, 2, 4, 5-tetracarboxylic acid is used to 100 g of the mixed solvent. The resulting electrolyte gives a low specific resistance electrolytic capacitor reliable at a high temperature and thus valuable for practical use in industry.

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 (hereinafter referred to as electrolytic solution).

[0002]

2. Description of the Related Art Conventionally, as an electrolytic solution for a low-voltage electrolytic capacitor, an electrolytic solution containing ethylene glycol as a main solvent and adipate dissolved therein has been widely used. Along with the adaptation to the change, an electrolytic solution in which γ-butyrolactone is used as a main solvent and a tetraalkylammonium salt of phthalic acid or maleic acid is dissolved is generally used.

[0003]

The electrolytic solution of the electrolytic capacitor in which tetramethylammonium salt of phthalic acid is dissolved in γ-butyrolactone is very reliable in a high temperature atmosphere, but its ratio is lower than the solubility limit. The resistance value was limited to 80 Ω · cm. On the other hand, the one obtained by dissolving the tetraethylammonium salt of maleic acid has a specific resistance value of 70 Ω · cm, but on the other hand, it has a drawback that the reliability is extremely low in a high temperature atmosphere due to maleic acid rearrangement and dehydration. Was.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and ensures reliability in a high temperature atmosphere while having a low specific resistance.

[0005]

That is, γ-butyrolactone is used as a main solvent, and tetraalkylammonium salt or tetraalkylphosphonium salt of benzene-1,2,4,5, -tetracarboxylic acid is dissolved. It is an electrolytic solution.

[0006]

In the electrolytic solution of the present invention, since solute rearrangement and dehydration do not easily occur, the reliability in a high temperature atmosphere can be sufficiently ensured, and since the tetrabasic acid has a low specific resistance. Can be realized.

[0007]

EXAMPLES Examples of the present invention will be described below. Table 1 shows comparative examples of the composition, the specific resistance and the spark generation voltage of the electrolytic solution of the present invention and the conventional electrolytic solution when the dissolved mass is 25% by weight. In addition, the electrolyte sample symbols A and B in Table 1 are conventional examples,
C and D are examples of the present invention, and γ-butyrolactone is GB
Abbreviated as L.

[0008]

[Table 1]

As is apparent from Table 1, the electrolytic solutions of the sample symbols C and D according to the present invention can have a lower specific resistance than the conventional electrolytic solutions. Table 2 shows electrolytic capacitors with a rated voltage of 25 V and 3300 μF, which were prototyped using the electrolytic solution shown in Table 1.
The results of high temperature load test at 105 ℃ for 2000 hours are shown below.

[0010]

[Table 2]

As is clear from Table 2, all characteristics of the electrolytic capacitors using the electrolytic solutions of sample symbols C and D according to the present invention have no problem even in a test in a high temperature atmosphere for a long time. In addition to these examples, those in which the alkyl group of the quaternary salt is composed of a propyl group, a butyl group, or the like,
Alternatively, the evaluation was also performed on those composed of various alkyl groups, and similar results were obtained. Although not shown in this example, since it is possible to mix with other solutes, the blending amount is arbitrary as long as it does not exceed the saturation concentration, but benzene-1, 100 g of the mixed solvent, If the tetraalkylammonium salt or tetraalkylphosphonium salt of 2,4,5, -tetracarboxylic acid is less than 5 g, it is impossible to lower the specific resistance of the electrolytic solution, and if it exceeds 30 g, solute precipitation is observed. Be done.

[0012]

As described above, γ-butyrolactone is used as the main solvent, and the tetraalkylammonium salt or tetraalkylphosphonium salt of benzene-1,2,4,5, -tetracarboxylic acid is dissolved. The electrolyte is
It has low specific resistance and high reliability even in a high temperature atmosphere, and has great industrial and practical value.

Claims (2)

[Claims] 1. For driving an electrolytic capacitor, characterized in that a tetraalkylammonium salt or a tetraalkylphosphonium salt of benzene-1,2,4,5, -tetracarboxylic acid is dissolved using γ-butyrolactone as a main solvent. Electrolyte. 2. The tetraalkylammonium salt or tetraalkylphosphonium salt of benzene-1,2,4,5, -tetracarboxylic acid is 5 to 30 g per 100 g of the mixed solvent.
The electrolytic solution for driving the electrolytic capacitor according to claim 1, which is present.