JPH0897094A - Electrolytic solution for driving electrolytic capacitors - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an electrolytic solution for driving an electrolytic capacitor, in which the gas generated by the boehmite reaction of the cathode aluminum foil is suppressed without increasing the specific resistance and the reliability is improved. [Structure] A solvent comprising ethylene glycol and water, a solute comprising an organic carboxylic acid salt, and at least one additive selected from starch, dextrin, glucose and glucose, wherein the additive is 0.01 An electrolytic solution for driving an electrolytic capacitor, which is 10% by weight.

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 Generally, an electrolytic solution for driving an electrolytic capacitor is required to have a low specific resistance value and stable characteristics in a wide temperature range. In an electrolytic solution containing ethylene glycol and water as a solvent and an organic carboxylic acid salt as a solute, the proportion of water is increased in order to reduce the resistance. However, when the proportion of water is increased, gas is generated by the boehmite reaction of the cathode aluminum foil in the capacitor element, and particularly at high temperatures, the gas is remarkably generated, so that the explosion-proof valve is activated and the reliability is improved. There is a problem that it becomes low.

[0003]

As described above, in the driving electrolyte solution using ethylene glycol and water as the solvent and the salt of the organic carboxylic acid as the solute, the gas due to the boehmite reaction that occurs in the cathode aluminum foil due to the presence of water. However, there is a drawback that gas is generated remarkably at a high temperature, and there has been a demand for this solution.

The present invention solves the above problems and suppresses gas generation due to the boehmite reaction of the cathode aluminum foil without increasing the specific resistance and improves the reliability of the electrolytic capacitor driving electrolytic solution. The purpose is to provide.

[0005]

Means for Solving the Problems The present inventors have diligently studied the above problems in an electrolytic solution containing ethylene glycol and water as a solvent and an organic carboxylate as a solute, and as a result, starch and dextrin were added to the electrolytic solution. The inventors have found that the addition of glucose or glucose suppresses the boehmite reaction of the cathode aluminum foil without increasing the specific resistance even if the proportion of water is increased, and arrived at the present invention. That is, the present invention is a solvent composed of ethylene glycol and water, a solute composed of a salt of an organic carboxylic acid,
An electrolytic solution for driving an electrolytic capacitor, comprising at least one additive selected from starch, dextrin, glucose and glucose, and the additive is 0.01 to 10% by weight.

Since the organic carboxylic acid salt used as a solute in the present invention must be soluble in a solvent, ammonium salts and amine salts are used, and specific examples thereof include succinic acid, adipic acid, azelaic acid, Examples thereof include ammonium salts of sebacic acid, 1.6-decanedicarboxylic acid, maleic acid, citraconic acid, and alkylamine salts having 1 to 4 carbon atoms. Among these, ammonium sebacate is particularly preferably used.

In the present invention, starch as an additive,
Dextrin, glucose or glucose is used, and a mixture of these can also be used. The appropriate amount of addition is 0.01 to 10% by weight. If the added amount is too large beyond this range, the capacitance and the value of tan δ become large. Further, if the addition amount is too small, the generation of gas due to the boehmite reaction cannot be suppressed.

In the present invention, by adding the additives as described above, it is possible to suppress the boehmite reaction of the cathode aluminum foil without increasing the specific resistance even if a large amount of water is contained in order to reduce the resistance. You can In particular, since it exhibits the effect of suppressing gas generation at high temperatures, stable performance can be obtained in a wide temperature range, and the reliability of the electrolytic capacitor can be significantly improved.

[0009]

According to the electrolytic solution for driving an electrolytic capacitor configured as described above, one or two of starch, dextrin, glucose and glucose are contained even if a large amount of water is contained to reduce resistance. By adding 0.01 to 10% by weight of one or more additives, the boehmite reaction of the cathode aluminum foil can be suppressed without increasing the specific resistance. In particular, since it exhibits the effect of suppressing gas generation at high temperatures, stable performance can be obtained in a wide temperature range, and the reliability of the electrolytic capacitor can be significantly improved.

[0010]

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples. In Tables 1 to 16, the unit of the specific resistance is Ω · cm, the unit of the spark voltage is V, and the valve operation means that the valve operation was caused by the gas generation and could not be measured.

(Example A) As shown in Tables 1 and 2 below, an electrolytic solution comprising an example and a comparative example in which the addition ratio of dextrin to the driving electrolytic solution was changed and a conventional example in which no dextrin was added was prepared. 25 made by each electrolyte
The specific resistance and the spark voltage at ° C were measured.

[0012]

[Table 1]

[0013]

[Table 2]

As is clear from Tables 1 and 2, in Examples 1 and 2, no increase in resistivity or decrease in spark voltage was observed.

Next, a rating of 2 was produced using the driving electrolyte solutions of the examples, comparative examples and conventional examples shown in Tables 1 and 2 above.
Initial characteristics of capacitance, tan δ, leakage current and high temperature load test (applying rated voltage at 105 ° C, 1
The results of examining the electrostatic capacity, tan δ, leakage current, generated gas amount, and valve operation number after 000 hours) are shown in Tables 3 and 4.

[0016]

[Table 3]

[0017]

[Table 4]

As is clear from Tables 3 and 4, the difference between the initial values of Examples 1 and 2 and the conventional example is small, but in the conventional example after the high temperature load test, it was caused by the boehmite reaction of the cathode aluminum foil. All valves are operated due to gas. Further, in Comparative Example 1 in which the added amount of dextrin was as small as 0.005% by weight, the number of valves that could not suppress the gas generation after the high temperature load test was large, and the added amount of dextrin was 12% by weight. In Example 2, the capacitance change rate and the value of tan δ are large.

(Example B) In the above (Example A), the case where dextrin was used as an additive was described. In this (Example B), the case where starch is used is described. The same samples (shown in Tables 5 and 6) as in (Example A) except that starch was used as an additive were prepared and tested.

[0020]

[Table 5]

[0021]

[Table 6]

As is clear from Tables 5 and 6, no increase in the specific resistance and no decrease in the spark voltage were observed in Examples 3 and 4. Then, Examples 3 and 4 shown in Tables 5 and 6 above.
And electrolytic capacitors having a rated voltage of 250 V-47 μF produced using the driving electrolytic solutions of Comparative Examples 4, 5, 6 and 10 capacitors each, initial characteristics of capacitance, tan δ and leakage current as in (Example A). Tables 7 and 8 show the results of examining the characteristics, the amount of generated gas, and the number of valve operations after the high temperature load test (applied rated voltage at 105 ° C. for 1000 hours).

[0023]

[Table 7]

[0024]

[Table 8]

As is clear from Tables 7 and 8, in Comparative Example 4 in which the amount of starch added was as small as 0.005% by weight,
In Comparative Example 5 in which a large number of valves were operated without suppressing the gas generation after the high temperature load test and the starch addition amount was 12% by weight, the capacitance change rate and the tan δ were large. , (Example A).

(Example C) As an additive, dextrin was used in (Example A) and starch was used in (Example B), but in (Example C), glucose was used as an additive. Samples (shown in Tables 9 and 10) similar to (Example A) and (Example B) except that glucose was used as the additive were prepared and tested.

[0027]

[Table 9]

[0028]

[Table 10]

As is clear from Tables 9 and 10, no increase in the specific resistance and no decrease in the spark voltage were observed in Examples 5 and 6. Then, Example 5 shown in Tables 9 and 10 above
No. 6 and Comparative Examples 7, 8 and 9 electrolytic capacitors having a rated voltage of 250 V-47 μF, 10 each
For each of the (Example A) and (Example B), initial characteristics of capacitance, tan δ, leakage current, and characteristics after high temperature load test (rated voltage application at 105 ° C., 1000 hours), generated gas amount Table 1 shows the results of the investigation of the number of valve movements.
1, shown in Table 12.

[0030]

[Table 11]

[0031]

[Table 12]

As is clear from Tables 11 and 12, Comparative Example 7 in which the amount of glucose added was as small as 0.005% by weight
Then, the number of valves that operated after the high temperature load test could not be suppressed and the amount of glucose added was 12
In the comparative example 8 of weight%, the capacitance change rate and the value of tan δ are large, and almost the same results as in (Example A) and (Example B) are shown.

(Example D) As an additive, dextrin was used in (Example A), starch was used in (Example B), and glucose was used in (Example C).
In this (Example D), the case of using glucose will be described. Samples similar to (Example A), (Example B) and (Example C) except that glucose was used as the additive (Table 1).
3, shown in Table 14) were prepared and tested.

[0034]

[Table 13]

[0035]

[Table 14]

As is clear from Tables 13 and 14, no increase in the specific resistance and no decrease in the spark voltage were observed in Examples 7 and 8. Next, for each of 10 electrolytic capacitors of rated 250 V-47 μF, produced using the driving electrolytic solutions of Examples 7 and 8 and Comparative Examples 10, 11 and 12 shown in Tables 13 and 14 above (Examples) A), (Example B),
Similar to (Example C), initial characteristics of capacitance, tan δ, leakage current and high temperature load test (105 ° C., 1000 hours)
Table 1 shows the results of the investigation of the subsequent characteristics, the amount of generated gas, and the number of valve operations.
5, shown in Table 16.

[0037]

[Table 15]

[0038]

[Table 16]

As is clear from Tables 15 and 16, Comparative Example 10 in which the amount of glucose added was as small as 0.005% by weight.
In Comparative Example 11 in which the gas generation after the high temperature load test could not be suppressed and the valve operation was large, and the amount of glucose added was 12% by weight, the capacitance change rate and the value of tan δ were large. The results are almost the same as those of (Example A), (Example B) and (Example C).

Although the case where ammonium sebacate was used as the solute was described in the above embodiment, succinic acid, adipic acid, azelaic acid, sebacic acid, 1,6
Similar effects can be obtained by using salts of decanedicarboxylic acid, maleic acid, and citraconic acid.

Further, the case where starch, dextrin, glucose and glucose are used alone as the additives has been described. Two or more of these additives are added in an amount of 0.01 to 1
The same effect can be obtained even when added in the range of 0% by weight.

[0042]

As described above, according to the electrolytic solution for driving an electrolytic capacitor of the present invention, a solvent containing ethylene glycol and water and a salt of an organic carboxylic acid as a solute, starch, dextrin and glucose are used. , 0.01 to 10% by weight of one or more additives in glucose
Without increasing the specific resistance by adding t
An δ and ESR can be reduced. In addition, since the boehmite reaction that occurs in the cathode aluminum foil can be suppressed, it is possible to provide an electrolytic capacitor having a long life by suppressing the gas generation. This suppression of gas generation has a remarkable effect of improving the life characteristics especially at high temperatures.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuo Aoyama 182 Tayuhama Shinwari Niigata, Niigata Prefecture Mitsubishi Gas Chemicals Co., Ltd. Niigata Research Laboratory (72) Inventor Mayumi Haneda Tayuhama Shinwari 182 Niigata City, Niigata Prefecture Niigata Research Laboratory, Mitsubishi Gas Chemical Co., Ltd.

Claims (1)

[Claims] 1. A solvent comprising ethylene glycol and water, a solute comprising an organic carboxylate, and at least one additive selected from starch, dextrin, glucose and glucose, wherein the additive is 0. .01
An electrolytic solution for driving an electrolytic capacitor, characterized by being 10 to 10% by weight.