JPH10256092A - Electrolyte for driving electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent leakage of driving electrolyte by employing a salt of pyrazolidine group shown by a specific formula as a solute. SOLUTION: A driving electrolyte employing a salt of pyrazolidines shown by a formula (in the formula, R1 , R2 , R3 , R4 and R5 are selected, respectively, from hydrogen and methyl group) as a solute is used. Salt of pyrazolidine can be selected freely and a salt of organic carboxylic acid, e.g. phthalic acid or maleic acid, is preferably employed. Furthermore, a solvent principally comprising one or two kind of material selected from γ-butyrolactone and ethylene glycol is preferably employed. According to the arrangement, leakage of driving electrolyte can be eliminated.

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 An aluminum electrolytic capacitor is formed by encapsulating a capacitor element formed by winding an aluminum electrode foil together with a driving electrolyte in a case. As the case of such an aluminum electrolytic capacitor, a case of an upper opening type is generally used, and the upper opening is closed by a rubber sealing member. Extraction of the electrode from the capacitor element housed in the case is generally performed by connecting the extraction terminal of the capacitor element to a rivet that penetrates a rubber sealing member. Is composed of aluminum.

As an electrolyte for driving such an aluminum electrolytic capacitor, an electrolyte obtained by dissolving an organic carboxylic acid and boric acid or a salt thereof in a solvent mainly composed of ethylene glycol has been used. Was.
On the other hand, in recent years, as the impedance of the electrolytic capacitor has been reduced, the driving electrolyte has also been required to have a low resistance. An electrolytic solution in which a quaternary ammonium salt is dissolved is used. As described above, an electrolytic solution containing a quaternary ammonium salt of an organic carboxylic acid as a solute has the advantages of low specific resistance and stability even at high temperatures.

[0004]

However, as described above, when a driving electrolyte containing a quaternary ammonium salt of an organic carboxylic acid such as phthalic acid or maleic acid as a solute is used, the use of an electrolytic capacitor at the time of using an electrolytic capacitor is difficult. The driving electrolyte near the cathode becomes strongly alkaline. And in this case,
The strongly alkaline driving electrolyte degrades the rubber sealing member that seals the opening of the electrolytic capacitor, the aluminum lead-out terminal and rivets fixed to it, and the cathode of the rubber sealing member degrades. There is a possibility that a problem that the driving electrolyte leaks from the portion may occur, and there is a problem in reliability.

As described above, when a conventional electrolytic solution for driving an electrolytic capacitor using a quaternary ammonium salt as a solute is used, the specific resistance and the stability at a high temperature are excellent, but the use of the electrolytic capacitor is high. Occasionally, the driving electrolyte near the cathode becomes strongly alkaline, causing a problem that the driving electrolyte inside the rubber leaks from the cathode of the sealing member to the outside. There is.

SUMMARY OF THE INVENTION The present invention has been proposed to solve the above-mentioned problems of the prior art. It is an object of the present invention to provide an electrolytic capacitor which has a sufficiently small specific resistance and is stable even at high temperatures. By providing a highly reliable electrolytic solution for driving an electrolytic capacitor, the vicinity of the cathode sometimes does not become strongly alkaline, and the problem that the driving electrolyte leaks due to deterioration of the member due to the strong alkali does not occur. is there.

[0007]

The electrolytic solution for driving an electrolytic capacitor according to the present invention uses a salt of a pyrazolidine as a solute instead of the conventional quaternary ammonium salt. That is, the electrolytic solution for driving an electrolytic capacitor according to claim 1 is characterized in that a salt of a pyrazolidine compound represented by the following general formula (1) is used as a solute.

[0008]

Embedded image

However, in the formula (1), R1, R2, R
3, each of R4 and R5 is selected from hydrogen and a methyl group.

The driving electrolyte using the pyrazolidine salt represented by the general formula (1) as a solute has a sufficiently small specific resistance and a high temperature even at a high temperature, similarly to the case where a quaternary ammonium salt is used as a solute. It is stable. In addition, unlike a case where a quaternary ammonium salt is used as a solute, a driving electrolyte using a pyrazolidine salt as a solute does not become strongly alkaline near a cathode when an electrolytic capacitor is used. Terminal, rivet, etc. are not deteriorated. Therefore, it is possible to prevent a problem that the driving electrolyte leaks due to the deterioration of these members.

The pyrazolidine used in the electrolytic solution for driving an electrolytic capacitor according to the first aspect is, specifically, at least one pyrazolidine selected from the group of the pyrazolidines according to the second aspect. It is. That is,
This group of pyrazolidines comprises pyrazolidine, 1-
Methyl-pyrazolidine, 2-methyl-pyrazolidine, 4
-Methyl-pyrazolidine, 1,2-dimethyl-pyrazolidine, 1,3-dimethyl-pyrazolidine, 1,4-dimethyl-pyrazolidine, 1,5-dimethyl-pyrazolidine, 2,4-dimethyl-pyrazolidine, 4,5-dimethyl -Pyrazolidine, 1,2,3-trimethyl-pyrazolidine, 1,2,4-trimethyl-pyrazolidine, 1,
2,5-trimethyl-pyrazolidine, 1,3,4-trimethyl-pyrazolidine, 1,4,5-trimethyl-pyrazolidine, 1,2,3,4-tetramethyl-pyrazolidine, 1,2,4,5-tetra Methyl-pyrazolidine,
1,3,4,5-tetramethyl-pyrazolidine.

Further, in the electrolytic solution for driving an electrolytic capacitor according to the first or second aspect, a salt of pyrazolidine can be arbitrarily selected.
It is desirable to use salts of organic carboxylic acids such as phthalic acid and maleic acid.

On the other hand, in the electrolytic solution for driving an electrolytic capacitor according to any one of the first to third aspects, any solvent can be used. It is desirable to use a solvent mainly composed of one or two materials selected from butyrolactone and ethylene glycol.

[0014]

EXAMPLES Examples of the electrolytic solution for driving an electrolytic capacitor according to the present invention will be described below. First, Tables 1 and 2
Are the compositions of Examples 1 to 19 of the driving electrolyte using a pyrazolidine salt according to the present invention as a solute and the conventional examples 1 and 2 of the driving electrolyte using a quaternary ammonium salt as a solute according to the prior art. Is shown.

[0015]

[Table 1]

[0016]

[Table 2]

Next, Table 3 shows conventional examples 1 and 2 as described above.
5 shows test results obtained by examining the specific resistance at 25 ° C. and the spark generation voltage of each of the driving electrolytes of Examples 1 to 19 according to the present invention. Table 3 shows that each of the driving electrolytes of Conventional Examples 1 and 2 and each of the driving electrolytes of Examples 1 to 19 according to the present invention were manufactured.
Aluminum electrolytic capacitors of the same rating (25V-1
000 μF) in a closed vessel under the same conditions of a high-temperature load test (105 ° C., 2,000 hours), and the results of observing liquid leakage at the sealing portion are also shown.

[0018]

[Table 3]

As apparent from Table 3, each of the driving electrolytes of Examples 1 to 19 according to the present invention has a specific resistance which is substantially the same as that of each of the driving electrolytes of Conventional Examples 1 and 2. And the spark generation voltage is higher than that of the conventional examples 1 and 2. That is, Conventional Examples 1 and 2
While the specific resistance of Examples 1 to 19 according to the present invention is 90 to 110 Ωcm.
This is sufficiently small to the same level as or less than the conventional example. And while the spark generation voltage of Conventional Examples 1 and 2 is 80 to 110 V, the spark generation voltage of Examples 1 to 19 according to the present invention is 115 to 150 V,
It is clearly higher than in Conventional Examples 1 and 2.

Regarding the high-temperature load test in a closed container, in the aluminum electrolytic capacitors using the driving electrolytes of the conventional examples 1 and 2, 15 or 16 out of 20 capacitors, and more than half of the capacitors were used. A leak has occurred. On the other hand, in the aluminum electrolytic capacitors using the driving electrolytes of Examples 1 to 19 according to the present invention, there is no liquid leakage.

[0021] When the driving electrolyte according to the present invention is used, it is considered that the liquid leakage can be prevented for the following reasons. That is, since each of the driving electrolytes of Examples 1 to 19 uses a pyrazolidine salt as a solute, each of the driving electrolytes of Conventional Examples 1 and 2 using a quaternary ammonium salt as a solute is used. Unlike the case where the electrolytic capacitor is used, the vicinity of the cathode does not become strongly alkaline when the electrolytic capacitor is used, so that the rubber sealing member, the aluminum lead-out terminal, the rivet and the like do not deteriorate.

As described above, Embodiments 1 to 1 according to the present invention
The driving electrolytes of No. 9 can prevent the occurrence of the problem that the driving electrolytes leak out, and have extremely high reliability as compared with the driving electrolytes of Conventional Examples 1 and 2.

The present invention is not limited to Examples 1 to 19, and the specific composition of the electrolytic solution can be appropriately selected within the scope of the present invention. For example, in Examples 1 to 19, only one selected from the group of pyrazolidines described in claim 2 was used.
It is also possible to use more than one species, in which case also excellent effects can be obtained.

Further, in the above Examples 1 to 19, the case where only one of the salt of phthalic acid and the salt of maleic acid was used was described, but both the salt of phthalic acid and the salt of maleic acid were used. The same effect can be obtained, and in this case, similarly excellent effects can be obtained. Furthermore, salts of pyrazolidines can be arbitrarily selected, but usually, it is desirable to use salts of organic carboxylic acids such as phthalic acid and maleic acid as in Examples 1 to 19.

Further, in Examples 1 to 19, the case where only γ-butyrolactone was used as the solvent and the case where both γ-butyrolactone and ethylene glycol were used were described, but only ethylene glycol was used as the solvent. It is also possible to use other materials than γ-butyrolactone and ethylene glycol. However, basically, as in Examples 1 to 19, it is desirable to use a solvent mainly composed of one or two materials selected from γ-butyrolactone and ethylene glycol.

On the other hand, in Examples 1 to 19, the case where the present invention is applied to an aluminum electrolytic capacitor having a rating of 25V-1000 μF has been described. However, the driving electrolyte of the present invention is applicable to various electrolytic capacitors having various ratings. In the same manner as in Examples 1 to 19, excellent effects can be obtained.

[0027]

As described above, according to the present invention, by using a pyrazolidine salt as a solute in place of the conventional quaternary ammonium salt, the specific resistance is sufficiently small and stable at high temperatures. However, when using an electrolytic capacitor, the vicinity of the cathode does not become strongly alkaline, and there is no problem that the driving electrolyte leaks due to deterioration of the member due to strong alkali. An electrolyte can be provided.

Claims (4)

[Claims] 1. An electrolytic solution for driving an electrolytic capacitor enclosed in a case together with a capacitor element, wherein a salt of a pyrazolidine compound represented by the following general formula (1) is used as a solute. liquid. Embedded image However, in this formula (1), R1, R2, R3, R4, R
Each of 5 is selected from among hydrogen and methyl groups. 2. The pyrazolidine, wherein the pyrazolidine is
1-methyl-pyrazolidine, 2-methyl-pyrazolidine, 4-methyl-pyrazolidine, 1,2-dimethyl-pyrazolidine, 1,3-dimethyl-pyrazolidine, 1,4
-Dimethyl-pyrazolidine, 1,5-dimethyl-pyrazolidine, 2,4-dimethyl-pyrazolidine, 4,5-dimethyl-pyrazolidine, 1,2,3-trimethyl-pyrazolidine, 1,2,4-trimethyl-pyrazolidine,
1,2,5-trimethyl-pyrazolidine, 1,3,4-
Trimethyl-pyrazolidine, 1,4,5-trimethyl-
One or two selected from pyrazolidine, 1,2,3,4-tetramethyl-pyrazolidine, 1,2,4,5-tetramethyl-pyrazolidine, 1,3,4,5-tetramethyl-pyrazolidine 2. The electrolytic solution for driving an electrolytic capacitor according to claim 1, wherein the electrolytic solution is at least one kind. 3. The electrolytic solution for driving an electrolytic capacitor according to claim 1, wherein the pyrazolidine salt is an organic carboxylic acid salt. 4. The solvent according to claim 1, wherein the solvent is a solvent mainly composed of one or two materials selected from γ-butyrolactone and ethylene glycol. 3. The electrolytic solution for driving an electrolytic capacitor according to item 1.