JPH0371616A - Electrolyte for driving electrolytic capacitor - Google Patents

Abstract

PURPOSE:To make it possible to obtain excellent corrosion-resisting property by a method wherein m-nitroacetophenone is added to an electrolyte. CONSTITUTION:To an electrolyte m-nitroacetophenone is added. It is known that there is no decrease in spark voltage of the electrolyte when the above- mentioned additive is added in the quantity up to 4wt.% to the electrolyte composed of 86wt.% ethylene glycol, 2wt.% water, 8wt.% ammonium borate and 4wt.% borasic acid for example. Using the above-mentioned electrolyte, the capacitor element, which is wound through the intermediaries of aluminum, cathode foil and a separator, is dipped, the capacitor element is incorporated into an aluminum case together with a hole-sealing material, and an electrolytic capacitor is manufactured. As a result, excellent corrosion-resisting property can be obtained without impairing spark voltage characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrolytic solution for driving an electrolytic capacitor used in an aluminum electrolytic capacitor.

[Prior Art] In an aluminum electrolytic capacitor, a capacitor element is made by winding an anode foil and a cathode foil made of aluminum foil with a separator interposed in between, and is impregnated with a driving electrolyte. It has a structure enclosed within.

The electrolytic solution is an organic acid such as carboxylic acid or its salt, an inorganic acid such as boric acid or its salt, or a mixture thereof dissolved as a solute in a solution mainly composed of an organic polar solvent such as ethylene glycol or γ-butyrolactone. things are used.

[Problems to be Solved by the Invention] In order to improve the corrosion resistance of the electrode foil made of aluminum foil, a small amount of p-nitrobenzoic acid and an ion exchanger ( halogen supplement) is added.

Although the addition of p-nitrobenzoic acid has the effect of absorbing hydrogen gas generated from the electrode foil, it has the disadvantage of causing a decrease in the spark voltage of the electrolyte.

Furthermore, although the addition of an ion exchanger has the effect of supplementing free halogen, it has the drawback of reducing the ability of the electrolyte to repair aluminum chemical conversion coatings and of having poor uniform dispersibility in the solvent.

[Means for Solving the Problems] The present invention has developed an electrolytic solution that has corrosion resistance by adding additives such as those described above that do not impair other properties of the electrolytic solution. Al. Specifically, m
- An electrolytic solution containing nitroacetophenone is provided.

[Examples] The present invention will be specifically described below based on Examples and Comparative Examples.

First, Table 1 shows the relationship between the composition of the electrolytic solution for driving an electrolytic capacitor and the spark voltage.

Table 1 Composition and spark voltage of electrolytic solution for driving an electrolytic capacitor Table 1 (Continued) Capacitor element using the electrolyte shown in Table 1 and winding an aluminum anode foil and a cathode foil with a separator in between. The capacitor element was impregnated with aluminum and the capacitor element was assembled together with the sealing body in an aluminum case to produce 30 electrolytic capacitors.

The electrolytes of Example 1 and Comparative Example 1 have a rating of 250V-100
IfF electrolytic capacitors were fabricated, Example 2 and Comparative Example 2
An electrolytic capacitor with a rating of 350 V and 22 μF was manufactured using the electrolytic solution of Example 3 and Comparative Example 3, and an electrolytic capacitor with a rating of 4.
A 00V/3.3μF electrolytic capacitor was manufactured.

These electrolytic capacitors are cleaned using substrate cleaning agent 1, 1.1.
- It was immersed in trichloroethane, subjected to ultrasonic cleaning for 10 minutes, and subjected to a high temperature load test at 105°C for 2000 hours. After this high-temperature load test, the product was disassembled and the occurrence of corrosion in the capacitor element was investigated. The results are shown in Table 2.

Table 2 High-temperature load test results As can be seen from Table 2, the electrolytic capacitor using the electrolyte according to the present invention exhibits an excellent corrosion inhibiting effect.

Next, FIG. 1 shows the relationship between the amount of m-nitroacetophenone added in the electrolyte and the spark voltage of the electrolyte. %, ammonium borate 8wt%
and shows changes in the amount of m-nitroacetophenone added to an electrolytic solution consisting of 4 wt% boric acid and the spark voltage of the electrolytic solution.

It can be seen that there is no decrease in the spark voltage of the electrolyte when up to 4 wt% of m-nitroacetophenone is added.6 [Effect] By using the electrolyte according to the present invention, the electrolyte itself can be used without impairing the spark voltage characteristics. , it is possible to provide an electrolytic capacitor with excellent corrosion resistance.

[Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between the amount of m-nitroacetophenone added in the electrolytic solution for driving an electrolytic capacitor according to the present invention and the spark voltage of the electrolytic solution.

Claims (1)

[Claims] (1) An electrolytic solution for driving an electrolytic capacitor, characterized in that m-nitroacetophenone is added.