JPS6170711A - Electrolyte for driving electrolytic condenser - 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] [Industrial Field of Application] The present invention relates to the improvement of an electrolytic solution for driving an electrolytic capacitor (hereinafter referred to as paste), and in particular to a paste for an electrolytic capacitor that makes it possible to extend the life of an electrolytic capacitor at high temperatures. It is something that takes place in between.

[Problems with Prior Art] Generally, in an electrolytic capacitor, a separator is interposed between anode and cathode foils, and the separator is wound to form an element, and the separator is impregnated with a liquid paste.

For this reason, when an electrolytic capacitor is used for a long period of time, the paste gradually evaporates and decreases, resulting in negative deterioration, which has the drawback that the life after trial is shorter than that of other capacitors.

Especially in recent years, with the progress of miniaturization and higher temperatures, electrolytic capacitors are often required to operate in a high temperature range of 100°C or higher.
The above drawbacks become a problem. Therefore, although efforts are being made to improve α-form paste (which can be used in high temperature ranges of 100"C or higher) and to develop sealing structures, measures against deterioration of properties due to evaporation of the paste are still insufficient. No solution has been obtained.

That is, the conventional 1α paste contains ethylene glycol, N
, N-dimethylformamide, methyl cellosolve, ethyl cellosolve, and other 81 solvents, monocarboxylic acids such as formic acid and maleic acid, or salts thereof, and electrolytes such as succinic acid and ammonium adipate are used. These pastes have high specific resistance values < (300Ω・c
m or more) impedance characteristics are deteriorated. Therefore, the specific resistance value is generally 130 as a mixed solvent with pure water added.
A paste with a temperature as low as -150 Ω・cm is used, but since the boiling point of this paste is as low as approximately 10°C by adding X water, for example, when used in an environment of 125°C, The drawback is that the paste evaporates rapidly and dries up in a short period of time, reaching the end of its service life. Therefore, such pastes are not suitable for use in high temperature regions.

[Problems to be Solved by the Invention] The present invention has been made in view of the above points, and provides an electrolytic capacitor that has a low resistivity value and a long life characteristic in a high temperature range of 100°C or higher. The purpose is to provide a driving paste.

[Means for Solving the Problems/Examples] Hereinafter, the present invention will be explained based on Examples with reference to tables and drawings.

The present invention provides a paste characterized in that r-butyrolactone is used as a solvent and phthalic acid and triethylamine are used as electrolytes. i example first
It is shown in the table.

γ-Butyrolactone has a high boiling point (204°C), so it is difficult to evaporate at high temperatures, and its viscosity is lower than that of solvents such as ethylene glycol that are conventionally used in pastes, so it has a low viscosity when dissolved in electrolytes. The specific resistance of the paste 1l
There is an advantage that II can be lowered. For γ-butyrolactone, we investigated an electrolyte that is stable and easily soluble in a high temperature range of 100'c or more and has a low specific resistance value.The result is that it can be obtained by reacting phthalic acid and triethiamine. We have found that triethylamine phthalate gives good results.

When phthalic acid and triethylamine are reacted in equal amounts with each mole number, the specific resistance of the resulting paste is minimized,
The reaction is shown by the following reaction formula.

Next, we further investigated the concentration and resistivity of triethylamine phthalate with respect to γ-butyrolactone, and the results were presented in the first section.
As shown in the figure.

As is clear from the figure, when the concentration of triethylamine phthalate is about 10 wt% or more, the resistivity value becomes minimum and saturates to a nearly constant value. Therefore, the concentration of triethylamine phthalate is preferably 10 wt% or more.

However, the concentration of triethylamine phthalate is 30wt.
% or more, some triethylamine phthalate will precipitate, so the appropriate concentration is 10 to 30 wt%. An example of the present invention shown in Table 1 is to add 0.105 m each of phthalic acid and triethylamine to the solvent of γ-butyrolactone.
The concentration of triethylamine phthalate produced by the reaction was adjusted to 29v12. In this case, the presence of unreacted phthalic acid will have a negative effect on the specific resistance (the specific resistance value will become high), so it is better to add a little more triethylamine than phthalic acid (approximately 1 H). The remaining triethylamine will evaporate and disappear, so there is no problem.Secondly, the characteristics of the paste of the present invention shown in Table 1 obtained in the above manner and the typical conventional paste shown in Table ':a3 A comparison is shown in Table 2.

[Operations and Effects] As mentioned above, the paste of the present invention employs γ-butyrolactone as a solvent, so the boiling point of the paste is significantly higher than that of conventional pastes as shown in Table 2, and Since it is a non-aqueous paste that does not contain pure water, Lb generation is suppressed when used at high temperatures, and the resistivity does not increase even in the absence of pure water. . Therefore, it can be expected to have a longer high-temperature life than conventional pastes. Furthermore, since the viscosity is lowered to about 115 (7 to BCP) compared to conventional pastes (30 to 40 CP), it has excellent impregnating properties into capacitor elements and low-temperature properties, and can be used in a wide temperature range.

Figure 2 shows that 10111 aluminum electrolytic capacitors of 10V-220μF were manufactured using the paste of the conventional embodiment shown in Table 3 and the paste of the present invention shown in Table 1. ) A high-temperature load test between I 000 Q was conducted in an atmosphere, and the results of investigating changes in capacitance are shown. As is clear from the figure, the rate of change in capacitance of the paste product of the present invention after 1000 hours was very small, and no abnormality was observed in its appearance. The capacity decreased and the internal elements were completely tried up after about 500 hours. It was also confirmed that all explosion-proof valves were activated and the cases were destroyed.

All conventional paste products are defective, but the original Uf
As mentioned above in J-, 74, pure water is added to lower the resistivity value and the boiling point of the paste is about 11.
Because it is as low as 0'C! In a 25'C atmosphere, the evaporation of the paste was severe, and the explosion-proof valve was operated in a short period of time, and all samples were tested.

On the other hand, the paste product of the present invention is a non-aqueous paste that does not contain pure water, but has a low resistivity value and has a high boiling point of 180°C, so evaporation occurs at high temperatures. Therefore, it can be seen that the above test is satisfied.

As explained above, the paste according to the present invention not only has excellent high-temperature life characteristics, but also has low viscosity, so it has excellent impregnating properties into elements and low-temperature characteristics, and therefore can be used at a wide temperature range from low to high temperatures. It also has the effect that it can be used over a wide range, and provides a highly reliable electrolytic capacitor paste with stable characteristics, which has great practical effects.

[Brief explanation of the drawing]

FIG. 1 is a characteristic diagram showing the specific resistance 11 iF of the paste of the present invention. FIG. 2 is a characteristic diagram showing the relationship between load test time and changes in characteristics.

Claims (2)

[Claims] (1) An electrolytic solution for driving an electrolytic capacitor, characterized in that it contains γ-butyrolactone as a solvent and phthalic acid and triethylamine as electrolytes. (2) Equal moles of phthalic acid and triethylamine are added to the solvent of γ-butyrolactone, and the concentration of triethylamine phthalate produced by the reaction of the phthalic acid and triethylamine is 10 wt% to 30 wt%. An electrolytic solution for driving an electrolytic capacitor according to claim (1).