KR950013420B1 - Electrolytri liquid for aluminium electrolytri capacitor - Google Patents

Abstract

The long life and high electrical conductivity electrolytic solution for aluminum electrolytic condenser is prepared by dissolving 15-25 wt% triethylmethylammonium salt of maleic acid into 72-84.5 wt% gamma butyrolactone solvent or its mixed solvent with ethylene glycol or methylcellosolve and 1 wt% sorbitol and para nitrobenzoate against the total weight as an additive for enhancing the voltage property of electrolytic solution.

Description

Electrolytic Solution for Aluminum Electrolytic Capacitors

The present invention relates to an electrolytic solution for aluminum electrolytic capacitors. More specifically, the present invention relates to an electrolytic solution for aluminum electrolytic capacitors that can be used for high frequency low impedance characteristics and long life products.

A conventional electrolytic solution for electrolytic capacitors was prepared by dissolving an electrolyte in ethylene glycol as a solvent. This type of electrolyte was prepared by adding water because of its high resistivity and poor impedance characteristics. However, since this electrolyte solution uses water, its vapor pressure is high at high temperatures, and it is easy to react with aluminum, and thus it is not suitable for use in a high temperature region.

As a technique for improving this problem, Japanese Patent Application Laid-Open No. 54-7,564 used triethyl ammonium salt of maleic acid as a kiln-butyrolactone solvent, and Japanese Patent Application Laid-open No. 61-70, 711, Triethyl ammonium salt of phthalic acid was used in the gamma-butyrolactone solvent.

In addition, Japanese Patent Application Laid-Open No. 63-118, 018 and Korean Patent Publication No. 92-8790 used tetramethyl ammonium salt of phthalic acid as a gamma-butyrolactone solvent, and Japanese Patent Application Laid-Open No. 63-226 In 912, tetramethyl ammonium salt of maleic acid was used as a gamma-butyrolactone solvent.

In addition, in Korean Patent Application Laid-Open Nos. 92-13 and 580, an electrolyte solution was prepared using a tetraethyl ammonium salt of phthalic acid in a gamma-butyrolactone solvent.

However, when the triethyl ammonium salt of phthalic acid or maleic acid is used, the acid dissociation degree is due to the protonation equilibrium of triethyl amine, resulting in a decrease in ionic production and high specific resistance, and triethyl of phthalic acid or maleic acid used as a solute. Amronium salts are unstable at high temperatures and increase resistivity when used for long periods of time, which can cause changes in capacitor characteristics.

In addition, when the tetramethyl ammonium salt of phthalic acid or the tetraethyl ammonium salt of phthalic acid is used, the improvement of the impedance characteristic and the high temperature stability can be satisfactorily extended, but it does not have the characteristic which meets the needs of a user.

In order to solve the above problems, an object of the present invention is to provide an electrolytic solution for aluminum electrolytic capacitors having a low impedance characteristic in a high frequency region by reducing a specific resistance, and having high thermal stability and having a long life at high temperature.

In order to achieve this object, in the present invention, a triethylmethyl ammonium salt of maleic acid is mixed with a gamma-butyrolactone solvent alone or in a mixed solvent with methyl cellosolve, ethylene glycol, and the like, and paranitrobenzoic acid and sorbitol are used as additives. It was.

Hereinafter, the present invention will be described in detail.

The present invention dissolves 15 to 25% by weight of a gamma-butyrolactone solvent alone or a mixed solvent of ethylene glycol or methyl cellosolve with 72 to 84.5% by weight of triethylmethylammonium salt of maleic acid. The present invention provides an electrolytic solution for aluminum electrolytic capacitors by adding 1% nitrobenzoic acid and 1% sorbitol.

According to the present invention, at least one of paranitrobenzoic acid and sorbitol may be added to the electrolyte as an additive in an amount of 0.5 to 3% by weight.

As in the present invention, when a triethylmethyl ammonium salt of maleic acid is used as a solute in a gamma-butyrolactone solvent, the conductivity can be higher than that of tetramethyl or tetraethyl ammonium of phthalic acid, which is a conventional solute.

In the above additive, para-nitrobenzoic acid reduces the internal pressure of the condenser by suppressing the gas generated by the reaction between the electrolyte and the material used in the condenser by a reduction reaction. Therefore, it increases the stability of the product, sorbitol is to act to ensure the voltage characteristics of the electrolyte.

By adding sorbitol, which has not been used conventionally as an additive to the composition of the electrolyte according to the present invention, the electrolyte solution of the present invention has a 155% improvement in the spark generation voltage compared to the conventional electrolyte solution, resulting in a 140% improvement in the product voltage. Effect.

When the electrolyte according to the present invention is used in an aluminum electrolytic capacitor, the conductivity of the electrolyte is increased to reduce the loss of the capacitor, the impedance characteristic is reduced in the high frequency range, and the product voltage is increased by boosting the spark generation voltage. By giving it has the effect of widening the range of use of the electrolyte.

In addition, since the solvent and the solute used in the present invention have a small change in resistivity with respect to the temperature and the life test time and are stable, a long-life product can be used.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1

An electrolytic solution was prepared by dissolving 25 g of triethylmethyl ammonium of maleic acid in 75 g of gamma-butyrolactone. The specific resistance of this electrolyte solution was 72 Pa.cm/30 degreeC.

After fabricating a 25WV, 470μF electrolytic capacitor using this electrolyte, the impedance characteristics at 100 kHz were measured and found to be 0.0658. The results of the high temperature load test after applying the rated voltage of 105 ° C are shown in Table 1 below.

Example 2

An electrolytic solution was prepared by mixing 25 g of triethylmethyl ammonium maleic acid, 1 g of para-nitrobenzoic acid, and 1 g of sorbitol in a mixed solvent of 63 g of gamma-butyrolactone and 10 g of methyl cellosolve. The specific resistance of this electrolyte solution was 85 Pa · cm / 30 ° C.

The electrolytic capacitor was manufactured in the same manner as in Example 1 using this electrolyte, and the impedance characteristics at 100 kHz were measured. The result was 0.0764. The results of the high temperature load test were shown in Table 1 below.

Comparative Example 1

70 g of gamma-butyrolactone and 10 g of ethylene glycol dissolved 20 g of triethyl ammonium salt of maleic acid in a mixed solvent to prepare an electrolyte solution. The specific resistance of this electrolyte solution was 135 Pa · cm / 30 ° C.

Using the electrolyte, the electrolytic capacitor was manufactured in the same manner as in Example 1, and the impedance characteristic at 100 kHz was measured at 0.1556. The result of the high temperature load test was shown in Table 1 below.

Comparative Example 2

An electrolyte solution was prepared by dissolving 20 g of tetramethyl ammonium salt of phthalic acid in 80 g of gamma-butyrolactone. The specific resistance of this electrolyte solution was 103 Pa · cm / 30 ° C.

After the electrolytic capacitor was fabricated in the same manner as in Example 1 using this electrolyte solution, the impedance characteristic measured at 100 kHz was 0.1040. The results of the high temperature load test were shown in Table 1 below.

Comparative Example 3

An electrolyte solution was prepared by dissolving 20 g of tetramethylammonium salt of phthalic acid in a mixed solvent of 70 g of gamma-butyrolactone and 10 g of ethylene glycol. The specific resistance of this electrolyte solution was 115 Ω · cm / 30 ° C.

Using this electrolyte solution, the same electrolytic capacitor as in Example 1 was prepared, and the impedance characteristic measured at 100 kHz was 0.1232. The results of the high-temperature load test were shown in Table 1 below.

TABLE 1

※ tanδ: loss, LC is leakage current

According to the above table, since the specific resistance of the embodiment of the present invention is sufficiently low as compared with the comparative example, it can be seen that the initial loss characteristic and the impedance decreased from 0.13 평균 to 0.07 평균 on average.

In particular, in the high-temperature load test, the capacitor using the electrolyte solution of Comparative Example was mostly defective at 2,000 hours due to the high tanδ and capacity change rate due to the increased resistivity of the electrolyte solution.

However, since the specific resistance of the electrolyte solution according to the present invention was low and the tanδ change was small at 105 ° C. and 2,000 hours, it was possible to manufacture an electrolytic capacitor capable of exhibiting high temperature long life characteristics.

Since the electrolytic capacitor electrolyte solution of the present invention has a low specific resistance, it exhibits low impedance characteristics at high frequencies, suppresses gases generated when used at a high temperature for a long time, and has a long life effect due to less tanδ change. By using sorbitol as a material, the spark generation voltage is boosted to increase the product use voltage, thereby widening the range of use of the electrolyte, which has great economic and industrial effects.

Claims (2)

An electrolytic solution in which triethylmethylammonium salt of maleic acid is dissolved in gamma-butyrolactone alone or as a mixture of ethylene glycol and methyl cellosolve as a solvent, wherein an sorbitol is added as an additive. The electrolyte solution according to claim 1, wherein sorbitol is added in an amount of 1% by weight based on the total weight of the electrolyte solution.