JPH0437013A - Electrolyte for driving an electrolytic capacitor - Google Patents

Abstract

PURPOSE:To suppress considerable characteristic deterioration of electrolyte for driving an electrolytic capacitor under a high temperature atmosphere by mixing at least one type of various particular dibasic acid dielectrics into solution made primarily of particular glycol. CONSTITUTION:When at least one type of various particular dibasic acid dielectrics chained principally by polypropylene glycol acid ammonium or polypropylene oxide or by polymethylene glycol acid ammonium or polymethylene oxide are mixed into solution made primarily of ethylene glycol to prepare electrolyte for driving an electrolytic capacitor, the electrolyte in conjunction with aluminum electrode foil forms and appropriate complex while securing solubility and withstand voltage, thereby being able to suppress the considerable degradation of the electrolytic capacitor that occurs under a high temperature atmosphere.

Description

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

2. Description of the Related Art Conventionally, an electrolytic solution prepared by dissolving boric acid in a solution mainly containing ethylene glycol has been frequently used as a driving electrolytic solution (hereinafter referred to as electrolytic solution) for high-voltage aluminum electrolytic capacitors.

Problems to be Solved by the Invention When electrolytic capacitors are used at high temperatures, the conventional electrolyte solution consisting of ethylene glycol-based solution with boric acid dissolved cannot ensure reliability due to the generation of esterified water. The use of higher dibasic acids with a large number of carbon atoms was also considered, but these had problems such as significant property deterioration in high-temperature atmospheres due to low solubility or strong ability to form complexes with aluminum, especially in the presence of moisture. .

Therefore, the use of ammonium polyethylene glycolate was considered, but polymethylene oxide, which is the main chain of ammonium polyethylene glycolate, is too hydrophilic and its complex-forming ability is too weak, causing chemical damage to the dielectric oxide film. It did not have sufficient protection against deterioration and required fundamental countermeasures.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention adds various derivatives of dibasic acids having ammonium polypropylene glycolate or polypropylene oxide as a main chain, or polypropylene into a solution mainly composed of ethylene glycol. This electrolytic solution for an electrolytic capacitor is characterized by containing at least one kind of various dibasic acid derivatives having ammonium methylene glycolate or polymethylene oxide as a main chain.

Examples of various dibasic acid derivatives having ammonium polypropylene glycolate or polypropylene oxide as a main chain are shown below.

4HN00C-(C)12cHO). -COON84C
H9 (n, m are arbitrary integers) Function The electrolytic solution of the present invention contains polypropylene oxide in various derivatives of dibasic acids having ammonium polypropylene glycolate or polypropylene oxide as a main chain,
Or, since it is more hydrophilic than ammonium polymethylene glycolate or polymethylene oxylic acid, it maintains solubility and forms an appropriate complex with aluminum electrode foil, suppressing significant property deterioration in high-temperature atmospheres. be able to.

Example Examples of the present invention will be described below.

Table 1 shows comparative examples regarding the composition and specific resistance of electrolytes used in electrolytic capacitors of the present invention and conventional electrolytic capacitors.

In Table 1, electrolyte sample symbols A, B, C, and D are conventional examples, E,
F is an example of the present invention.

In this case, ammonium polypropylene glycolate having the following structural formula was used.

48N00C-(CH2CIlO)8-COONH4C
H.

Also, as ammonium polymethylene glycolate.
A compound having the following structural formula was used.

48NOOC-(CH20h□-COONH4 Table 1 Table 2 shows the results of a high-temperature load test at 105°C for 2000 hours on an aluminum electrolytic capacitor with a rating of 400 W to 1220 μF, which was prototyped using the electrolyte shown in Table 1. .

As is clear from Table 2 and Table 1, electrolyte E according to the present invention,
Compared to conventional electrolytes, F exhibits a higher withstand voltage than conventional electrolytes even though it has a low specific resistance value.

As is clear from Table 1, electrolyte E according to the present invention,
Compared to conventional electrolytes, F has significantly improved reliability in high-temperature environments.

Note that as the polypropylene oxide chain length or polymethylene oxide chain length increases, the withstand voltage tends to improve (as the average molecular weight increases), but the solubility also decreases accordingly, so it is important to choose an appropriate chain length. is necessary.

Also, those having an alkyl group or the like in the polypropylene oxide chain or polymethylene oxide chain exhibit similar effects.

As is clear from the test results above and beyond the effects of the invention, the electrolytic solution of the present invention maintains solubility and withstand voltage while forming an appropriate complex with aluminum electrode foil, making it suitable for electrolytic capacitors under high-temperature atmospheres. It is possible to suppress significant property deterioration, and is of great industrial and practical value.

Claims (1)

[Claims] Add various derivatives of dibasic acids whose main chain is ammonium polypropylene glycolate or polypropylene oxide, or various derivatives of dibasic acids whose main chain is ammonium polymethylene glycolate or polymethylene oxide to a solution mainly composed of ethylene glycol. An electrolytic solution for driving an electrolytic capacitor, characterized in that it contains at least one kind of electrolytic solution.