JPH02298009A - Electrolyte for electrolytic capacitor drive use - Google Patents

Abstract

PURPOSE:To suppress an increase in an internal pressure of an electrolytic capacitor at a high temperature and to sufficiently increase a sparking voltage without increasing a resistivity by a method wherein one out of hexits and boric acid or both of them are added to a solvent composed mainly of ethylene glycol, an acid selected from various kinds of carboxylic acids or one or two or more kinds of their salts are used as a main solute and all of them are dissolved. CONSTITUTION:A hexitol and boric acid or both of them are added to a solvent composed mainly of ethylene glycol; an acid selected from 1-methyl-1,7-heptane dicarboxylic acid, 1,7-dimethyl-1,7-heptane dicarboxylic acid, 1,3-dimethyl-1,3,9- nonane tricarboxylic acid and the like or one or two or more kinds of their salts are used as a main solute; all of them are dissolved and used as an electro lyte. As the salts, a secondary amine salt, a tertiary amine salt and a quaternary ammonium salt are used; as the hexites, mannite, sorbite, dulcite, xylite and penta-erythrite are used.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an electrolytic solution for driving electrolytic capacitors, and in particular to improving the characteristics of electrolytic capacitors for medium and high voltages.

Conventional technology Conventional electrolytic solutions for driving electrolytic capacitors, especially for medium and high voltage applications, have been made with boric acid or ammonium borate dissolved in ethylene glycol as an electrolyte because they can generate a relatively high spark generation voltage. .

However, in such an electrolytic solution, a large amount of water is generated in the electrolytic solution due to the crystallization water directly released from boric acid and the condensed water generated by the esterification reaction between ethylene glycol and boric acid. When used in an electrolytic capacitor with a temperature exceeding 200 mL, the problem is that the water in the electrolyte evaporates into water vapor, which increases the internal pressure inside the electrolytic capacitor package and destroys it. In order to solve these problems,
Examples of using butyloctanedioic acid as a solute, as seen in Japanese Patent Publication No. 13293, and Japanese Patent Publication No. 63-15738.
There is an example in which 5,6-decanedicarboxylic acid is used as a solute, as seen in the above publication. Since the esterification reaction in electrolytes using these tribasic acids or their salts is very slow, only a small amount of water is generated in the electrolyte, which suppresses the pressure rise inside the electrolytic capacitor package at high temperatures. I can do it.

Problems to be Solved by the Invention However, these tribasic acids or their salts alone have a drawback in that the spark generation voltage at high temperatures is insufficient.

The present invention solves these conventional drawbacks by suppressing the increase in internal pressure of electrolytic capacitors at high temperatures and without increasing specific resistance (driving medium-high voltage electrolytic capacitors with sufficiently high spark generation voltage). The purpose is to provide an electrolyte solution for

Means for Solving Problem W In order to solve the above problems, the electrolytic solution for driving an electrolytic capacitor of the present invention contains a solvent mainly composed of ethylene glyfur,
1-Methyl-1,7-heptanedicarboxylic acid, 1.7-
Dimethyl-1,7-heptanedicarboxylic acid, 1,3-dimethyl-1,3,9-nonanetricarboxylic acid, 1,3-
Dimethyl-3-carbomethoxy-1,9-nonanedicarboxylic acid, 1,3-dimethyl-1,7-heptanedicarboxylic acid, 1-methyl-3-ethyl-1,7hebutanedicarboxylic acid, 7-ethyl-1 , 16-hexadecanedicarboxylic acid, 7.12-dimethyl-1°18-octadecanedicarboxylic acid, ? ,8,11゜12-tetramethyl-1,
18-octadecanedicarboxylic acid, 7-methyl-1,1
4-tetradecanedicarboxylic acid, 7,8-dimethyl-1
, ll-tetradecanedicarboxylic acid, 1-methyl-1,
6-hexanedicarboxylic acid, 1,3-dimethyl-3-carbomethoxy-1,8-octanedicarboxylic acid, 1.3
-dimethyl-1,3,8-octane I dicarboxylic acid,
1-methyl-1,8-octanedicarboxylic acid, 1,3-
Dimethyl-3-carbomethoxy-1,10-decanedicarboxylic acid, 1,3-dimethyl-1,3,1'O-decanetricarboxylic acid, 7-phenyl-7-methoxy-1-octanecarboxylic acid, 6-phenyl The main solute is one or more acids selected from -6-methoxy-heptanecarboxylic acid, 6-ethyl-1,14-tetradecanedicarboxylic acid, or salts thereof, and hexites and boric acid. Either one or both are added and dissolved.

The above-mentioned hexybutates and boric acid may be added alone, but it is preferable to add them both for better solubility.

Further, the above-mentioned salts include secondary amine salts, tertiary amine salts, and quaternary ammonium salts, and a specific example of the secondary amine salts is dimethylamine salt.

Examples include diethylamine salt, dipropylamine salt, dibutylamine salt, dimethylethylamine salt, methylpropylamine salt, methylbutylamine salt, ethylpropylamine salt, ethylbutylamine salt, and propylbutylamine salt. Specific examples of tertiary amine salts include trimethylamine salt, dimethylethylamine salt, dimethylpropylamine salt, dimethylbutylamine salt, diethylmethylamine salt, methylethylpropylamine salt, methylethylbutylamine salt, dipropylmethylamine salt, methyl Propylbutylamine salt, dibutylmethylamine salt, triethylamine salt, diethylpropylamine salt, diethylbutylamine salt 2 dipropylethylamine salt, ethylpropylbutylamine salt, dibutylethylamine salt, tripropylamine salt, dipropylbutylamine salt, dibutylpropylamine salt, Examples include tributylamine salts. Specific examples of quaternary ammonium salts include tetramethylammonium salt, trimethylethylammonium salt, trimethylpropylammonium salt, trimethylbutylammonium salt, dimethyldiethylammonium salt, dimethylethylpropylammonium salt, dimethylethylbutylammonium salt, dimethyl Propylammonium salt, dimethylpropylbutylammonium salt 2
Dimethyldibutylammonium salt, triethylmethylammonium salt, diethylmethylpropylammonium salt, diethylmethylbutylammonium salt, dipropylmethylethylammonium salt, methylethylpropylbutylammonium salt, dibutylmethylethylammonium salt, tripropylmethylammonium salt, dipropyl Methylbutylammonium salt, dibutylmethylpropylammonium salt, tributylmethylammonium salt, tetraethylammonium salt, triethylpropylammonium salt, triethylbutylammonium salt, diethyldipropylammonium salt, diethylpropylbutylammonium salt, diethyldibutylammonium salt, tripropylethyl Ammonium salt, dipropylethylbutylammonium salt, dibutylethylpropylammonium salt.

Examples include tributylethylammonium salt, tetrapropylammonium salt, tripro and rubylammonium salt, dipropyldibutylammonium salt, and tributylpropylammonium salt.

Further, the structural formula of the acid used in the present invention is as follows.

tloocm(CL)e-C)I-COOHCH3 1-Methyl-1,7-heptanedicarboxylic acid C00)1 HOOC-(C)12)s-C-CHz-CH-CO
OHC)13 CH3 1,3-dimethyl-1,3,9-nonanetricarboxylic acid0OCR3)100C-(CH2)s-C-C1l 2-CtoC0
OH] l CH3CH3 1,3-dimethyl-3-carbomethoxy-1,9-nonanedicarboxylic acid HOOC-CH-(CH2)s-CH-COO)1CH
3ell 3 1.7-dimethyl-1,7-heptanedicarboxylic acid 7.8.11.12-tetramethyl-1,18-octanedecanedicarboxylic acid HOOC-(CH2)4-CB-CHt-CH-COO
)1] I C2H6CH3 1-Methyl-3-ethyl-1,7-heptanedicarboxylic acid 1,3-dimethyl-1,7-heptanedicarboxylic acid CH2 □ HOOC-(082)s-CH-(Ctl2)4-C
H-(CH2)8-COOHOH3 7,12-dimethyl-1,18-octadecanedicarboxylic acid HOOC-(Ctl2)s-CO-(CH2)s-C
OOQC2)15 7-ethyl-1,16-hexadecanedicarboxylic acid Ctl+ □ HOOC-(Ctl2)s-CI-C)i-(C[
t2) 6-COOHCfh 7.8-dimethyl-1,14-tetradecanedicarboxylic acid HOOC-(CH2)s-CI-(CL h-COOt
lOH3 7-Methyl-1,14-tetradecanedicarboxylic acid HOOC-(CH2)s-Ctl-COOfl□ OH3 1-Methyl-1,6-hexanedicarboxylic acid C0DCH
3C113 HOOC-(Ctl2)s-C-CH2-CH-CO
OHOH3 1,3-dimethyl-3-carbomethoxy-1,8-octanedicarboxylic acid C0OHCH3 HOOC-(CH2)S-C-CH2-C)I-COO
HOH3 1,3-dimethyl-1,3,8-octanetricarboxylic acid C)13 HOOC-(CL)7-C-COO)! 1-Methyl-1,8-octanedicarboxylic acid C0DCH3CH3 HOOC-(Chh-CCtl2-CH-C0OHCH
3 1,3-dimethyl-3-carbomethoxy-1,10-decanedicarboxylic acid COOHC) is I HOOC-(CB2 h-C-Cfh-Ctl-COO
HOH3 1,3-dimethyl-1,3,10-decanetricarboxylic acid OH3 7-phenyl-7-methoxy-1-octanecarboxylic acid δH3 6-phenyl-6-medoxy-1-hebutanecarboxylic acid HOOC-(C)I 2) s-CH-(CH2)s-
COOI(Czl(s) 6-Ethyl-1,14-tetradecanedicarboxylic acid Effect By having the above-described structure, the acid of the present invention has a chemical property that is lower than that of butyloctanedioic acid and 5,6-decanedicarboxylic acid. As a result, the spark generation voltage increases, and by adding one or both of hexites and boric acid, it adsorbs to the surface of the anodic oxide film and covers the defective parts of the oxide film. Therefore, the spark generation voltage can be further increased.

Examples Examples of the present invention will be described below. First, the composition and resistivity of the conventional example and the example of the present invention, the spark starting voltage,
Table 1 shows a comparison of characteristics regarding moisture content.

(Margin below) Among the electrolytes shown in Table 1, electrolytic capacitors (rated 40
Table 2 shows the results of a high humidity pull load test for 1000 hours at a temperature of 105°C for 20 each of 0V270μF).
Table 3 also shows the short circuit occurrence rate during the test.

(Left below) As is clear from Tables 2 and 3, Example 1 of the present invention. The electrolyte of Example 18 was the same as that of Conventional Example 2. Compared to the electrolytic solution of Conventional Example 3, as a result of a high temperature ripple load test at 105°C, it was found to be superior in all characteristics such as short circuit occurrence rate, capacitance change rate, and tan δ variable ratio change rate, making it a highly reliable capacitor. Obtainable.

FIG. 1 shows a comparison of the formation and discharge characteristics during constant current formation between the electrolytic solution of Example 1 of the present invention and the electrolytic solution of Conventional Example 2.

Effects of the Invention As is clear from the description of the above embodiments, according to the present invention,
It is possible to obtain an electrolytic solution for driving medium-high voltage electrolytic capacitors that has a high spark generation voltage without increasing specific resistance. By using such an electrolyte, it is possible to obtain extremely reliable medium-high voltage electrolytic capacitors. It is possible to provide electrolytic capacitors for

[Brief explanation of drawings]

FIG. 1 is a characteristic diagram showing a comparison of formation/discharge characteristics during constant current formation between an electrolytic capacitor driving electrolytic solution according to an embodiment of the present invention and a conventional electrolytic capacitor driving electrolytic solution.

Claims (9)

[Claims] (1) 1-methyl-1,7-heptanedicarboxylic acid, 1,7-dimethyl-1,7-heptanedicarboxylic acid, 1,3-dimethyl-1,3,9- Nonanetricarboxylic acid, 1,3-dimethyl-3-carbomethoxy-1,9-nonanedicarboxylic acid, 1,3-dimethyl-1,7-heptanedicarboxylic acid,
1-Methyl-3-ethyl-1,7-heptanedicarboxylic acid, 7-ethyl-1,16-hexadecanedicarboxylic acid, 7,12-dimethyl-1,18-octadecanedicarboxylic acid, 7,8,11,12- Tetramethyl-1,18
-Octadecanedicarboxylic acid, 7-methyl-1,14-
Tetradecanedicarboxylic acid, 7,8-dimethyl-1,1
4-tetradecanedicarboxylic acid, 1-methyl-1,6-
Hexanedicarboxylic acid, 1,3-dimethyl-3-carbomethoxy-1,8-octanedicarboxylic acid, 1,3-dimethyl-1,3,8-octanetricarboxylic acid, 1-methyl-1,8-octanedicarboxylic acid , 1,3-dimethyl-3-carbomethoxy-1,10-decanedicarboxylic acid, 1,3-dimethyl-1,3,10-decanetricarboxylic acid, 7-phenyl-7-methoxy-1-octanecarboxylic acid, The main solute is one or more acids selected from 6-phenyl-6-methoxy-heptanecarboxylic acid and 6-ethyl-1,14-tetradecanedicarboxylic acid, or salts thereof, and hexites. An electrolytic solution for driving an electrolytic capacitor, characterized in that one or both of boric acid and boric acid are added and dissolved therein. (2) The electrolytic solution for driving an electrolytic capacitor according to claim 1, wherein the hexite is mannitol, sorbitol, dulcitol, xylitol, or pentaerythritol. (3) The electrolytic solution for driving an electrolytic capacitor according to claim 1, wherein the salt is an ammonium salt. (4) The electrolytic solution for driving an electrolytic capacitor according to claim 1, wherein the salt is a secondary amine salt. (5) The electrolytic solution for driving an electrolytic capacitor according to claim 1, wherein the salt is a tertiary amine salt. (6) The electrolytic solution for driving an electrolytic capacitor according to claim 1, wherein the salt is a quaternary ammonium salt. (7) The substituent of the secondary amine salt is a methyl group, an ethyl group,
5. The electrolytic solution for driving an electrolytic capacitor according to claim 4, characterized in that the electrolyte contains one or two selected from propyl groups and butyl groups. (8) The substituent of the tertiary amine salt is a methyl group, an ethyl group,
The electrolytic solution for driving an electrolytic capacitor according to claim 5, characterized in that the electrolyte contains one or more selected from propyl groups and butyl groups. (9) The electrolytic capacitor driving electrolytic capacitor according to claim 6, wherein the substituent of the quaternary ammonium salt is one or more selected from methyl group, ethyl group, propyl group, and butyl group. liquid.