JPH08293437A - Electrolyte for driving electrolytic capacitor - Google Patents

Abstract

PURPOSE: To improve for a long time variations in the capacitance and tanδ of an electrolytic capacitor at high temperature by adding to a solution with an organic solvent and electrolytic salt bases one or more compounds selected from among amine derivatives expressed by a specific formula. CONSTITUTION: An electrolyte for driving electrolytic capacitors is prepared by adding one or more compounds, selected from among amine derivatives expressed by the formula (however, R1 , R2 =H, CH3 , C2 H5 , C3 H7 , C4 H9 , Ph) to solution composed of an organic solvent and electrolytic salt. Since these amine derivatives are easily absorbed to metal, they will bee absorbed to electrode foil and protect it. This suppresses hydration and the like of such an electrode foil. Since the amine derivatives are unreactive to the compositions of electrolyte, such as ethylene glycol, it is possible to improve for a long time variations in the capacitance and tanδ of an electrolyte capacitor at high temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic solution for driving an electrolytic capacitor.

[0002]

2. Description of the Related Art In recent years, with downsizing and high reliability of electronic equipment, there is a demand for downsizing and high reliability of electrolytic capacitors used therein.

The miniaturization of the electrolytic capacitor is usually carried out by improving the electrostatic capacity of the electrode foil, but the effective electrode area is reduced by improving the electrostatic capacity of the electrode foil, and as a result, the equivalent series. The resistance increases, and it is necessary to increase the conductivity of the electrolytic solution in order to reduce the increased equivalent series resistance.

In response to such a need, in the conventional electrolytic solution mainly composed of ethylene glycol, it has been attempted to improve the electric conductivity by adding water to improve the dissociation degree of the electrolyte salt.

[0005]

However, when water is added to the electrolytic solution, the larger the amount of water added, the more the hydration reaction with aluminum serving as the electrode is promoted. And the loss tangent (tan δ) increase.

In order to prevent this decrease in electrostatic capacity, for example, JP-A-63-7613 discloses an electrolytic solution containing glycine, L-aspartic acid, alanine and glutamic acid, which is disclosed in JP-A-64-37823. An electrolytic solution containing glycine, alanine, and valine is disclosed in JP-A-3-91225.
JP-A-3-257811 discloses an electrolytic solution containing glycine and alanine, and JP-A-3-257811 discloses an electrolytic solution containing a silane coupling agent.

However, since these additives easily react with the electrolyte composition such as water and ethylene glycol, they have a short-term effect but no long-term effect.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide an electrolytic solution for driving an electrolytic capacitor, which can improve the capacitance change and tan δ change of the electrolytic capacitor at high temperature for a long period of time. It is what

[0009]

In order to achieve the above object, the electrolytic capacitor driving electrolytic solution of the present invention is selected from the amine derivatives represented by the chemical formula 2 in a solution mainly composed of an organic solvent and an electrolyte salt. At least one compound is added.

[0010]

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[0011]

The electrolytic solution for driving the electrolytic capacitor having the above-mentioned structure is obtained by adding at least one compound selected from the amine derivative shown in Chemical formula 3 to a solution consisting of an organic solvent and an electrolyte salt. Since the amine derivative is easily adsorbed on the metal, it is adsorbed on the electrode foil to protect the electrode foil, which makes it difficult for the hydration reaction of the electrode foil to occur.

Further, since the reactivity with the electrolytic solution composition such as water or ethylene glycol is low, it is possible to improve the capacitance change and tan δ change of the electrolytic capacitor at high temperature for a long period of time.

[0013]

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[0014]

EXAMPLES An example of the present invention will be described below.

The basis of the present invention is to add at least one compound selected from the amine derivatives represented by the chemical formula 4 to a solution mainly composed of an organic solvent and an electrolyte salt.

[0016]

[Chemical 4]

As the organic solvent usable in the present invention, for example, amides, lactones, glycols, sulfur compounds or carbon salts are preferable. Specific examples thereof include N-methylformamide, γ-butyrolactone and β.
-Butyrolactone, γ-valerolactone, N-methylpyrrolidone, ethylene glycol, ethylene glycol
Monoalkyl ether, ethylene glycol dialkyl ether, dimethyl sulfoxide, propylene carbonate,
Examples thereof include ethylene cyanohydrin, and these solvents can be used alone or in combination of two or more.

Ammonium salts, amine salts, quaternary ammonium salts, and the like can be used as the electrolyte salt dissolved in such an organic solvent, and as the amine salt, methylamine, ethylamine, dimethylamine, diethylamine, trimethylamine, Triethylamine and dimethylethylamine are preferable, and as the quaternary ammonium salt,
Tetramethylammonium, tetraethylammonium, methyltriethylammonium, ethyltrimethylammonium and dimethyldiethylammonium are preferred.

Table 1 shows the compositions of the electrolytic solutions of the examples of the present invention and the conventional examples.

[0020]

[Table 1]

(Table 2) prepares electrolytic solutions for driving electrolytic capacitors having the respective compositions shown in (Table 1), and using these electrolytic solutions, a constant voltage of 10 V and a nominal capacitance of 100 μF.
Of the aluminum electrolytic capacitor, and the initial capacitance value (12
0Hz), tan δ (120Hz) and leakage current value, 9
3 shows the rate of change in capacitance, tan δ, and leakage current value when a high temperature load test was performed at 5 ° C. for 2000 hours.

[0022]

[Table 2]

As is clear from (Table 2), the conventional examples 2 and 3 are smaller in capacitance change than the conventional example 1 and are effective, but are compared with the first, second and third examples of the present invention. And the change in capacitance is large. Further, in the conventional examples 2 and 3, the tan δ change after the high temperature load test with respect to the initial characteristics is large, and the effect of the additive on this tan δ change is not seen, but in Examples 1, 2 and 3 of the present invention, tan
The change in δ was much smaller than in Conventional Examples 1, 2, 3, and 4, and the effect of the additive was observed.

Therefore, each of the embodiments of the present invention can improve the characteristic change of the electrolytic capacitor at high temperature as compared with each of the conventional examples, and particularly the effect of improving both the capacitance change and the tan δ change. Is a large and highly reliable electrolytic capacitor.

In Examples 1, 2 and 3 of the present invention, as is apparent from (Table 1), p-aminobenzoic acid-n-butyl and benzylethanolamine were used as amine derivatives. Is N, N-dibutyl-m-aminophenol, N-phenyl-β-naphthylamine,
With pn-aminophenol, the same effect as in the example can be obtained. Further, the addition amount of the amine derivative to be added is preferably in the range of 0.01 to 2.0% by weight based on the weight of the electrolytic solution. That is, if it is less than 0.01% by weight, the effect is small, while if it exceeds 2.0% by weight, it is difficult to dissolve it. A range of 2.0% by weight is preferred.

[0026]

INDUSTRIAL APPLICABILITY As described above, the electrolytic capacitor driving electrolytic solution of the present invention is a solution comprising an organic solvent and an electrolyte salt to which the amine derivative represented by Chemical formula 5 is added. Since it is easily adsorbed on the electrode foil, it is adsorbed on the electrode foil to protect the electrode foil, and this makes it difficult for the hydration reaction of the electrode foil to occur. It can be improved.

[0027]

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Claims (2)

[Claims] 1. An electrolytic solution for driving an electrolytic capacitor, which is obtained by adding at least one compound selected from the amine derivative represented by the chemical formula 1 to a solution mainly composed of an organic solvent and an electrolyte salt. Embedded image 2. The amine derivative is N-phenyl-β-naphthylamine, n-butyl p-aminobenzoate, p-
n-aminophenol, benzylethanolamine,
It is any one of N, N-dibutyl-m-aminophenol, and the addition amount thereof is 0.01 to the weight of the electrolytic solution.
The electrolytic solution for driving an electrolytic capacitor according to claim 1, which is 2.0% by weight.