JP2003332174A - Electrolytic solution for driving electrolytic capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrolytic solution for driving an electrolytic capacitor, which can prolong the service life of an electrolytic capacitor. <P>SOLUTION: Since the hydration deterioration of an aluminum electrode foil can be suppressed when a higher dibasic acid, such as azelaic acid, 1,6- decanedicarboxylic acid, 7-vinylhexadecene-1,16-dicarboxylic acid, etc., or its salt and/or a boric acid or its ammonium salt, and 0.1-1.0 wt.% murexide (Fig. 1) are dissolved by using ethylene glycol as a main solvent, the service life of the electrolytic capacitor can be prolonged. <P>COPYRIGHT: (C)2004,JPO

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 electrolytic capacitor (hereinafter referred to as an electrolytic solution), and particularly to a long life of the electrolytic capacitor.

[0002]

2. Description of the Related Art Conventionally, an electrolytic capacitor for medium and high voltage uses an electrolytic solution prepared by dissolving a higher dibasic acid or its ammonium salt in a solvent containing ethylene glycol as a main component. In recent years, the electrolytic capacitor is used in a severer condition, and a ripple current is applied at a high temperature. Therefore, when used for a long time, the aluminum electrode foil is hydrated and deteriorated, and the electrical characteristics of the electrolytic capacitor are deteriorated.

[0003]

Therefore, by preventing hydration deterioration of the aluminum electrode foil even in a severe situation where a ripple current is applied to the electrolytic capacitor at high temperature,
There has been a demand for a technique for further prolonging the life of the electrolytic capacitor.

[0004]

The present invention is to solve the above-mentioned problems and uses ethylene glycol as a main solvent,
An electrolytic solution for driving an electrolytic capacitor, characterized in that a higher dibasic acid or a salt thereof and / or boric acid or an ammonium salt thereof and murexide (Chemical Formula 2) are dissolved.

[0005]

[Chemical 2]

The amount of dissolved murexide is 0.
The electrolytic solution for driving an electrolytic capacitor is characterized in that it is 1 to 1.0 wt%.

Further, as the higher dibasic acid, azelaic acid, sebacic acid, 1,6-decanedicarboxylic acid, 5,
6-decanedicarboxylic acid, 7-vinylhexadecene-
1,16-dicarboxylic acid etc. can be illustrated.

And as the salt of the higher dibasic acid,
In addition to ammonium salts, methylamine, ethylamine, t
-Primary amine salts such as butylamine, secondary amine salts such as dimethylamine, ethylmethylamine, diethylamine,
Examples thereof include tertiary amine salts such as trimethylamine, diethylmethylamine, ethyldimethylamine and triethylamine, and quaternary ammonium salts such as tetramethylammonium and triethylmethylammonium.

In addition to water, other subsolvents to be mixed with ethylene glycol include glycols such as propylene glycol, lactones such as γ-butyrolactone and N-methyl-2-pyrrolidone, N-methylformamide, N, N.
-Dimethylformamide, N-ethylformamide,
Amides such as N, N-diethylformamide, N-methylacetamide, N, N-dimethylacetamide, N-ethylacetamide, N, N-diethylacetamide, hexamethylphosphoric amide, ethylene carbonate, propylene carbonate, isobutylene carbonate, etc. Examples thereof include carbonates, nitriles such as acetonitrile, oxides such as dimethylsulfoxide, ethers, ketones, esters, sulfolane and derivatives thereof.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In an electrolytic solution in which ethylene glycol is used as a main solvent and a higher dibasic acid or its salt and / or boric acid or its ammonium salt and murexide are dissolved, murexide forms a complex with aluminum ions. Therefore, it is possible to suppress the hydration deterioration of the aluminum electrode foil even under the severe conditions that the ripple current is applied at high temperature and the temperature inside the electrolytic capacitor becomes higher than the ambient temperature, and the electrolytic capacitor is further improved. The life can be extended.

[0011]

EXAMPLES The present invention will be specifically described below based on examples. An electrolytic solution was prepared according to the electrolytic solution composition shown in Table 1 and rated at 450
After impregnating each capacitor with V / 270μF capacitor element,
An electrolytic capacitor having an anode / cathode lead wire and a sealing body having an external terminal connected to each other and assembled in a capacitor case and sealed was subjected to a ripple current superposition test in a thermostatic chamber at 105 ° C. As the ripple current, the current value at which the product temperature rise was 10 ° C was used. The product is disassembled every 1000 hours after the start of the test to check whether the aluminum electrode foil is hydrated or not,
The results shown in Table 1 were obtained.

[0012]

[Table 1]

From Table 1, in the conventional example in which murexide was not dissolved, the aluminum electrode foil was hydrated and deteriorated in 3000 to 4000 hours. However, in this example in which murexide was dissolved, hydration deterioration of the aluminum electrode foil was not observed even after 5000 hours had passed.

The amount of murexide dissolved is 0.1 wt%
If it is less than 1.0%, the effect of suppressing hydration deterioration of the aluminum electrode foil is small, and if it exceeds 1.0% by weight, the solute is likely to precipitate when the product is left at a low temperature of 0 ° C. or less, so that the dissolved amount of murexide is 0. The range of 0.1 to 1.0 wt% is preferable.

Further, the effect of the present invention is not limited to the embodiment, and the same effect as that of the embodiment can be obtained with an electrolytic solution in which each of the solutes illustrated above is dissolved alone or in plural, or an electrolytic solution in which a sub solvent is mixed. was gotten.

[0016]

As described above, according to the present invention, an electrolytic capacitor using ethylene glycol as a main solvent and an electrolytic solution in which higher dibasic acid or its salt and / or boric acid or its ammonium salt and murexide are dissolved is used. Is capable of suppressing the hydration deterioration of the aluminum electrode foil even when it is used for a long time at a high temperature and with overlapping ripples, and makes it possible to extend the life of the electrolytic capacitor.

Claims (2)

[Claims] 1. An electrolytic capacitor for driving an electrolytic capacitor, characterized in that ethylene glycol is used as a main solvent to dissolve higher dibasic acid or a salt thereof and / or boric acid or an ammonium salt thereof and murexide (Chemical Formula 1). liquid. [Chemical 1] 2. The dissolved amount of murexide according to claim 1,
An electrolytic solution for driving an electrolytic capacitor, which is 0.1 to 1.0 wt%.