JPS61240624A - Driving electrolytic liquid for electrolytic capacitor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an electrolytic solution for driving an electrolytic capacitor (hereinafter referred to as electrolytic solution).

First Conventional technology Conventionally, the electrolyte for electrolytic capacitors uses ethylene glycol as the main solvent, adipic acid, and formic acid.

Many are used that have organic acids such as benzoic acid and their salts, or inorganic acids and their salts such as boric acid and phosphoric acid as solutes. In capacitors using these conventional electrolytes, corrosion may occur during high-temperature loads, resulting in deterioration of characteristics. In order to prevent deterioration due to this corrosion,
As seen in Japanese Patent Publication No. 58-6298, a method has been proposed in which boron oxide is added to the electrolytic solution as a corrosion inhibitor, but although this has a certain degree of prevention effect, the properties in high-temperature load tests are significantly deteriorated. In addition, special public service 58-
Although a method of adding a silver compound has been proposed as in Japanese Patent No. 1538, the solubility in a solvent is low and a sufficient effect of preventing corrosion has not been obtained.

(c) Problems to be Solved by the Invention Conventional electrolytes have had problems such as corrosion during high-temperature loads.

B) Means for Solving the Problems The present invention is characterized in that boron salicylic acid or a salt thereof is dissolved in an electrolytic solution consisting of a solvent and a solute.

(e) Effects Borodisalicylic acid and its salts form a complex with chloride ions, which are the cause of corrosion, and take out the chloride ions out of the corrosion reaction system, which is thought to produce a corrosion-preventing effect.

(f) Example In the present invention, ethylene glycol is used as the main solvent.1 For example, ethylene glycol solvent,''!
, a mixed solvent of ethylene glycol and methylcarpitol, or a mixed solvent of ethylene glycol and methyl cellosolve or N-ethylpolamide.

A mixed solvent such as diethylene glycol and dimeterformamide is used.

In the present invention, the solute is adipic acid.

Ammonium salts and amine salts of organic acids such as formic acid and benzoic acid, and ammonium salts and amine salts of boric acid, maleic acid, and arbilaic acid are used.

In the present invention, borodisalicylic acid or a salt thereof is added to and dissolved in a solution consisting of the above-mentioned solute and solvent. The amount of this borodisalicylic acid or its salt added is preferably 5! It is most preferably 0.5 g to 2 oy.

The present invention will be explained in more detail below using specific examples. Table 1 shows four types of electrolytes (
, A) ~ (TI)] and a conventional electrolyte (G) for comparison.
)aP) (G) is shown.

Table 1 and Table 2 show the rating of 16 using each of the above electrolytes (A) to (G).
After making prototypes of 20 aluminum electrolytic capacitors each impregnated with QV and 10μF elements.

The results of an accelerated high temperature load test at 135°C are shown.

The structure of the sample capacitor is a well-known structure in which a capacitor element is made by winding chemically etched aluminum foil with separator paper in between, impregnated with electrolyte, and this element is placed inside an aluminum case using a rubber backing. It is stored.

Table 2 105℃ rated voltage applied It is.

As is clear from Table 2, in the accelerated high-temperature load test of capacitors at 105° C. and 1000 hours of rated voltage application, corrosion and abnormalities were observed with the conventional electrolyte during the test. Corrosion here refers to corrosion of the aluminum lead portion extending from the capacitor element to the sealing portion. On the other hand, in the electrolytic liquids () to (D) according to the present invention, such abnormalities were not observed at all, indicating the corrosion-preventing effect of borodisalicylic acid and its salts.

Further, the amount of addition of borodisalicylic acid or its salt will be explained using ammonium borodisalicylate as an example. Figure 1 shows 100% of ethylene glycol as a solvent and 10% of ammonium adipate as a solute. FIG. 2 is a characteristic diagram showing the relationship between the chemical formation voltage resistance when the amount of ammonium borodisalicylate added to an electrolytic solution having a basic composition dissolved in ft- is varied.

Generally, chemical conversion treatment is carried out at a main voltage of about 20 to 3 degrees of the rated voltage, so from Figure 1, in order to use it for capacitors with a rated voltage of 100 WV (work volts) or more, the amount of solvent added must be 10 to 30 degrees. -20. ! It is preferable to make it less than or equal to i'. Furthermore, for those with a rated voltage of less than 1° OW' V, it is thought that the same effect can be obtained even if a higher amount is added.

Next, as another embodiment of the present invention, the electrolytes (T) (J) shown in Table 3 and the electrolytes (A) (B) (0) described above
and P) (G3 was prepared, and the capacitor characteristics under high temperature load were measured.

Table 5 Table 4 shows each of the above electrolytes (N) (0) (c) (IIGT
) and □□□) sides were made in the same manner as described above, and aluminum electrolytic capacitors were made by impregnating the sample capacitor, and then a high temperature load test at 105° C. was conducted. The results are shown below.

Table 4 105℃ rated voltage applied As is clear from Table 4, in the conventional electrolyte.

In contrast, the deterioration of capacitor characteristics such as the occurrence of corrosion is significant, whereas in the case of the present invention, borodilyrithylic acid and its tolerant addition lI [I amount is 0.59 or more per ml of M medium' + 00 ml, corrosion occurs. It can be seen that the product has the effect of prolonging the life of the product, as it has been found to be effective in preventing leakage and improving high-temperature load characteristics.

(G) As explained in detail about the invention, 1. The electrolytic solution according to the present invention hardly deteriorates the capacitor characteristics even under long-term high-temperature loads, and it is possible to extend the life of electrolytic capacitors. can.

[Brief explanation of drawings]

FIG. 1 is a characteristic diagram showing the relationship between the amount of ammonium borodisalicylate added to the driving electrolyte of the electrolytic capacitor of the present invention and the chemical formation voltage resistance.

Claims (1)

[Claims] (1) An electrolytic capacitor characterized in that borodisalicylic acid or its salt is dissolved in an electrolytic solution in which one or more organic acids, inorganic acids, or their salts are dissolved as solutes in a solvent mainly composed of ethylene glycol. driving electrolyte.