JPS63122112A - New 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 [Field of Industrial Application] The present invention relates to an electrolytic capacitor using a novel driving electrolyte.

[Prior Art] Conventionally, the driving electrolytic solution for an electrolytic capacitor is an electrolytic solution that uses ethylene glycol as the main solvent and dissolves therein as an electrolyte a salt that does not corrode metal electrodes, such as an ammonium salt of an organic acid. Generally used, however, it has been difficult to reduce the impedance of the electrolyte because it generally has a large specific resistance. For this reason, although electrolytic capacitors have excellent other characteristics, their high frequency characteristics are inferior to other capacitors such as ceramic capacitors.

Conventionally, several types of driving electrolytes with relatively low resistivity have been known. For example, an electrolytic solution consisting of ammonium adipate, ethylene glycol, and water, with a water content of 20% by weight. has a conductivity of approximately 7 mS. Furthermore, in order to lower the specific resistance, it is conceivable to further increase the water content, but a large water content in the electrolytic solution is undesirable because it causes an increase in the vapor pressure of the electrolytic solution at high temperatures.

Furthermore, there is a highly conductive electrolytic solution in which quaternary ammonium chlorine and dibasic carboxylic acid are dissolved in a mixed medium of a dipolar solvent and water (Japanese Patent Application Laid-open No. 78522/1983). However, in this case, the electrical conductivity is the highest, according to the example, 9.4.
mS, which is not that large.

[Problems to be Solved by the Invention] The present invention achieves low impedance by using a driving electrolyte having particularly low specific resistance, that is, high conductivity.
The purpose is to provide an electrolytic capacitor with excellent high frequency characteristics.

[Means for Solving the Problems] The present invention satisfactorily achieves the above object, and the present invention provides at least one organic or inorganic acid salt of tetraalkylphosphonium or tetraarylphosphonium, preferably one to one. An electrolytic capacitor characterized by using a driving electrolyte comprising an organic solvent containing 60% by weight.

The alkyl group of the above-mentioned tetraalkylphosphonium preferably has 1 to 4 carbon atoms, and for example, tetramethylphosphonium, tetraethylphosphonium, tetrapropylphosphonium, tetrabutylphosphonium, dimethyldiethylphosphonium, etc. are preferable from the viewpoint of solubility and availability. .

The aryl group of the tetraarylphosphonium preferably has 1 to 2 benzene nuclei, and is particularly preferably a phenyl group. The benzene nucleus may have an appropriate substituent.

On the other hand, as inorganic acid salts, boric acid (BF4), hexafluorophosphoric acid (2-6), perchloric acid (ClO2), hexafluoroarsenic acid (Ash), hexafluoroantimonic acid (SbF6)
), salts of aluminic acid tetrachloride (AICIn), and the like are preferred, among which ClOs salts and BF4 salts are particularly preferred.

As the organic acid salt, chain dicarbonate (carbon number 1-12
2 to 10) or salts of aromatic carboxylic acids are preferred, especially maleic acid.

Succinic acid, glutaric acid, adipic acid, benzoic acid, phthalic acid, salicylic acid, pyromellitic acid.

Salts such as halogenated benzoic acids are preferred. Also, Rf
Fluorine-containing organic acid salts represented by COO or RfSO3 are also preferred, where the Rf group represents a fluoroalkyl group having 1 to 8 carbon atoms, especially a perfluoroalkyl group having 1 to 3 carbon atoms. is preferred.

As the polar organic solvent, any polar organic solvent commonly used in electrolytic capacitors can be used. As preferred solvents, formamides, lactones, glycols, sulfur compounds or carbonates can be used. Preferred specific examples include propyl sulfolane carbonate, dimethylformamide, N-methylformamide, butyrolactone, N-methylpyrrolidone, dimethylsulfokide, ethylene, cyanohydrin, ethylene glycol, monoalkyl ether of ethylene glycol, and the like.

When the content of the tetraalkylphosphonium salt or the tetraarylphosphonium salt is small, it is not preferable because the specific resistance will not become sufficiently small, and conversely, even if the content is too large, the specific resistance will not decrease beyond a certain level, so there is no point. The concentration of the phosphonium salt in the electrolytic solution is preferably 1 to BO% by weight, more preferably 3 to 40f.
Particularly preferred is f1 amount%.

20% by weight or less of water may be added to the electrolytic solution. By adding water, the specific resistance can be made slightly smaller. However, adding more than 20% by weight is not preferable because it increases the internal pressure of the capacitor at high temperatures.

Electrolytic capacitors of the present invention include a variety of preferably aluminum capacitors. In a typical embodiment, an aluminum foil anode and an aluminum foil cathode separated by a suitable spacer such as paper are used, these are wound into a cylindrical shape to form a capacitor element, and this element is impregnated with a driving electrolyte. . The amount of electrolyte impregnated is preferably 5
The content is 0 to 300% by weight. The element impregnated with the electrolyte is housed in a case made of corrosion-resistant metal or synthetic resin.
It is made into a sealed structure.

Below, specific examples showing preferred embodiments of the present invention,
I will explain further.

Note that the present invention should not be construed as being limited by the above proofs and examples, and various modifications can be made within the scope of the present invention.For example, the driving electrolyte used in the present invention If necessary, other substances such as organic carboxylic acids, boric acid, phosphoric acid,
Of course, polyhydric alcohols, ammonia, amines, etc. can also be added.

[Examples and Comparative Examples] Table 1 shows examples using phosphonium salts along with comparative examples. It was found that the specific resistance could be reduced to less than half that of the comparative example. Furthermore, Table 2 shows the characteristics of a 35V, 220JLF capacitor manufactured using the electrolyte shown in Table 1.

Table 3 shows examples of use in combination with other carboxylic acids, which shows that by adding a quaternary ammonium salt, the specific resistance can be reduced without reducing the spark voltage.

Table 1 Table 2 Table 3 [Effects of the Invention] The electrolytic capacitor of the present invention has extremely low specific resistance, that is, by using a driving electrolyte having high conductivity,
It enables low impedance and has excellent high frequency characteristics.

Furthermore, the spark voltage and low-temperature to high-temperature characteristics are as excellent as those of the prior art.

Procedure Nei17 Positive (↓F 1986/ρ month/q day

Claims (2)

[Claims] (1) An electrolytic capacitor characterized by using a driving electrolyte in which an organic or inorganic acid salt of tetraalkylphosphonium or tetraarylphosphonium is dissolved in an organic solvent. (2) Concentration of organic acid salt or inorganic acid salt is 1 to 60% by weight
An electrolytic capacitor according to claim 1.