JP2000306779A - Electrolyte for activating aluminum electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress increase in leakage current at a high temperature by dissolving adipic acid or its salts, as a dissolved substance, into a solvent that mainly consists of ethylene glycol and adding 2-hydroxybenzylalcohol that is indicated by a specific expression. SOLUTION: Adipic acid or its salts are dissolved as a dissolved substance into a solvent that mainly consists of ethylene glycol, an electrolyte where 2-hydroxybenzylalcohol indicated by an expression is added is used, and an electrolyte capacitor is manufactured. The deteriorated coating of an anode foil is recovered by the operation of the 2-hydroxybenzylalcohol to suppress the increase in a leakage current at high temperatures. The amount of the 2-hydroxybenzylalcohol to be added preferably ranges from 0.05 to 3.0 wt.%, thus obtaining an electrolyte with a small leakage current at high temperatures and improving the characteristics of the electrolytic capacitor and improving its reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an electrolytic solution for driving an aluminum electrolytic capacitor (hereinafter referred to as an electrolytic solution), and more particularly to an electrolytic solution for suppressing an increase in leakage current in a high temperature load test. .

[0002]

2. Description of the Related Art Generally, an electrolytic capacitor has a surface area enlarged by etching a high-purity aluminum foil, and a separator paper is interposed between an anode foil having its surface formed and an etched cathode foil facing the anode foil. An element having a structure wound and wound is impregnated with an electrolytic solution, the element is housed in a case, and sealed with a sealing body. In such an electrolytic capacitor, the characteristics of the electrolytic solution are a major factor in determining the performance of the electrolytic capacitor. Particularly, with the recent miniaturization of electrolytic capacitors, those having a high etching ratio have been used and the equivalent series resistance of the capacitors has been increased. Always required. Among the conventional electrolytes, the one with low cost and low specific resistance is a solution in which ethylene glycol is used as a main solvent and water is added thereto, and an ammonium salt of a carboxylic acid such as adipic acid is dissolved as an electrolyte. I have.

[0003]

However, when the amount of water added to the electrolytic solution is increased, the specific resistance can be reduced.
Electrolytic capacitors using such an electrolytic solution have a problem that the leakage current in a high-temperature load test increases remarkably, and a means for suppressing the increase in the leakage current at a high temperature and providing a highly reliable electrolytic capacitor is required. It had been.

[0004]

In order to solve the above-mentioned problems, the present invention suppresses deterioration of the aluminum foil film by adding 2-hydroxybenzyl alcohol having a high chemical conversion property as shown in Chemical formula 2 to the electrolytic solution. In addition, it is intended to suppress an increase in leakage current. That is, an electrolytic solution for driving an aluminum electrolytic capacitor, characterized in that adipic acid or a salt thereof is dissolved as a solute in a solvent mainly composed of ethylene glycol, and 2-hydroxybenzyl alcohol shown in Chemical formula 2 is added.

[0005]

Embedded image In addition, the present invention provides an electrolytic solution for driving an aluminum electrolytic capacitor, wherein the amount of the 2-hydroxybenzyl alcohol to be added is 0.05 to 3.0 wt%.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An electrolytic capacitor is manufactured by using an electrolytic solution to which 2-hydroxybenzyl alcohol is added. The deteriorated film of the anode foil is repaired by the action of 2-hydroxybenzyl alcohol, and an increase in leakage current at high temperatures is suppressed.

[0007]

Embodiments of the present invention will be described below. Table 1 shows the results of comparing the electrolyte compositions of Examples 1 to 6 according to the present invention and the electrolyte compositions of Conventional Examples 1 and 2 and the specific resistance at 30 ° C. for comparison.

[0008]

[Table 1]

[0009] Further, using the above-mentioned electrolyte, a rated voltage of 50 V-1
Fifty 000 μF aluminum electrolytic capacitors were each manufactured and subjected to a no-load test at 105 ° C. for 1000 hours. The results shown in Table 2 were obtained.

[0010]

[Table 2]

As shown in Table 2, although the leakage current of the aluminum electrolytic capacitor using the conventional electrolytic solution (conventional examples 1 and 2) is large, the electrolytic solution according to the present invention (Examples 1 to 2)
Aluminum electrolytic capacitor using 6) is 105 ° C
Even after 1000 hours, the increase in leakage current is small, and stable electric characteristics are shown.

As a result of various studies on the amount of 2-hydroxybenzyl alcohol, 0.05 to 3.0 wt%
Was appropriate. If the content is less than 0.05 wt%, the effect of suppressing the increase in leakage current does not appear, and if it exceeds 3.0 wt%, the specific resistance becomes too high, which is a problem.

[0013]

As described above, according to the present invention, by adding 2-hydroxybenzyl alcohol, an electrolyte having a small leakage current at high temperatures can be obtained. Therefore, the improvement of the characteristics and the reliability of the electrolytic capacitor can be realized at low cost, and the industrial and practical value is great.

Claims (2)

[Claims] An adipic acid or a salt thereof is dissolved as a solute in a solvent mainly composed of ethylene glycol.
An electrolytic solution for driving an aluminum electrolytic capacitor, characterized by adding 2-hydroxybenzyl alcohol shown in (1). Embedded image 2. The electrolytic solution for driving an aluminum electrolytic capacitor according to claim 1, wherein the amount of the 2-hydroxybenzyl alcohol is 0.05 to 3.0 wt%.