JPS6124219A - 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] [Field of Industrial Application] The present invention relates to an electrolytic solution for driving an electrolytic capacitor,
This prevents deterioration of the electrolyte, prevents an increase in leakage current during voltage application to the electrolytic capacitor, and prevents corrosion of the capacitor element, thereby providing an electrolytic capacitor that has a long life and high reliability even at high temperatures. .

[Conventional technology and problems]

Generally, the electrolytic solution for driving aluminum electrolytic capacitors uses ethylene glycol as the main solvent, and water (0%
, 1 to 30%) and further dissolve ammonium carboxylate as an electrolyte. However, in this type of electrolyte, especially at high temperatures, the ammonium carboxylate in the electrolyte undergoes an amidation reaction to become amide and water, resulting in a change in its composition, which can have an adverse effect on the electrolyte properties. . Furthermore, when electrolytic capacitors using this type of electrolyte are applied with high voltage at high temperatures, leakage current may increase, and in severe cases, corrosion may occur in the aluminum capacitor element, which may shorten its lifespan. Not only did it have a short lifespan, but it was not possible to fully expect its reliability.

[Improvements and outline of the invention]

However, the present invention aims to eliminate the above-mentioned drawbacks. Specifically, in order to suppress the amidation reaction, the hydrogen of the ammonium group of ammonium carboxylate is converted into a three-dimensional alkyl group, phenyl group, or cycloalkyl group. By using one or more substituted carboxylic acid alkylammonium salts, carboxylic acid phenylammonium salts, or carboxylic acid cycloalkylammonium salts as an electrolyte, changes in the composition of the electrolytic solution are prevented, the electrolyte properties are stabilized, and leakage is prevented. The present invention provides an aluminum electrolytic capacitor that is highly reliable and has a long life at high temperatures without increasing current or corroding capacitor elements.

In the present invention, aliphatic carboxylic acids will be described as carboxylic acids, but examples of production of general alkyl ammonium salts, phenylammonium salts, and cycloalkylammonium salts of aliphatic carboxylic acids are as follows.

(1) Example of production of alkylammonium salt HOQO(OH
2) nooOH+2(0+Hs)3N-(C'2Hs
)3HNOOO0(OH2) n OOONH(02H
5)3(2) Production example of ferrammonium salt HOO
O(OH2) n C0OH+2 @-CH2cH2N
H3→■-0H2CH2NH3000(OH3) n
cOONH3CH2OH2@(3) Production example of cycloalkylammonium salt HOOO(OH2n C0OH
+20-NH2-ONH3000(OH2)nooON
Aliphatics of Hs O carbonic acid include sebacic acid, 1
There are 10-decanedicarboxylic acid and 1,6-decanedicarboxylic acid, and representative examples of their alkylammonium salts, phenylammonium salts, and cycloalkylammonium salts are as follows.

(4) Typical example of sebacic acid Alkylammonium salt... Triethylammonium sebacate phenylammonium salt = -... Phenylethylammonium sebacate cycloalkylammonium salt... Cyclohexylammonium sebacate (5 ) Typical examples of 1,10-decanedicarboxylic acid Alkylammonium salt... 1.10-decanedicarboxylic acid isopropylammonium phenylammonium salt... 1.1o-decanedicarboxylic acid phenylethylammonium cycloalkylammonium salt... ...1.1
0-y” cyclohexylammonium candicarboxylate (6) Typical example of 1,6-decanedicarboxylic acid Alkylammonium salt... 1.6-decanedicarboxylic acid triethylammonium 1
．． 6-decanedicarboxylic acid diisopropylammonium phenylammonium... 1.6-tekanedicarboxylic acid phenylethylammonium cycloalkylammonium... 1.6 = cyclohexylammonium tecanedicarboxylate [Example] Next, the above-mentioned One or more electrolytes of alkyl ammonium salts, phenyl ammonium salts, or cycloalkylammonium salts of aliphatic carboxylic acids are combined with polyhydric alcohols such as ethylene glycol and diethylene glycol, and glycols such as ethylene glycol and monomethyl ether. Ethers, ethers such as ethylene glycol monomethyl ether acetate, or γ
Table 1 shows examples of the electrolytic solution according to the present invention, which was added together with water to a mixed organic polar solvent consisting of two or more of γ-lactones such as butyrolactone and amines such as dimethylformamide, together with conventional examples. Shown below.

The composition of the electrolytic solution is wt%, and the specific resistance (Ωcrn) is the one at the liquid temperature of 20°C.

Table 1 Composition of electrolyte Also, among the electrolytes shown in Table 1, 0 each of electrolytic capacitors (rated 400V, 10μF) using the electrolytes of Conventional Example 1, Example 1, and Example 6 , 105℃, 1
The second example of the results of a high temperature load test for 000 hours is shown below.
Shown in the table. The values of the initial characteristics and the characteristics after the test shown in Table 2 are the average values of 20 electrolytic capacitors. The number of corrosion occurrences was determined by disassembling the electrolytic capacitor after the test was completed.

Table 2 Characteristic Comparison Next, among the electrolytes similarly shown in Table 1, the conventional example, Example 1, and Example 6 were sealed at high temperature for a long period of time, and Table 3 shows the results of investigating the maximum voltage (v) of the electrolytic solution when a small amount of compound was added, together with the results when it was added to the electrolytic solution before being left standing. Specifically, the electrolyte was heated to 100°C at 11.0°C.
Leave it sealed in a stainless steel container for 0 hours, and add a small amount of potassium chloride to the electrolyte after leaving it at Oppm, 50 ppm,
100pp, 100pp, ppm was added, and an aluminum plain group was used as the anode and cathode at a temperature of 85° C., and was determined from the voltage change over one hour during anodization at a constant current.

Table 3 Comparison of characteristics (maximum reached voltage) [Effects of the invention] As can be seen from Table 2, in the conventional example, after the test, the capacitance change rate was large, the leakage current increased slightly, and corrosion occurred. This is occurring in all cases. On the other hand, in the embodiment according to the present invention, the capacitance change rate is small and the leakage current is well suppressed. Furthermore, no corrosion occurred.

As mentioned above, this phenomenon in the conventional example shown in Table 2 can be largely attributed to the deterioration of the driving electrolyte, that is, the decrease in the electrolyte concentration due to the amidation reaction. On the other hand, the present invention can prevent such a phenomenon by suppressing the amidation reaction, and can provide a highly reliable aluminum electrolytic capacitor that has a long life at high temperatures.

In addition, as can be seen from Part 3, in the conventional example, when the concentration of potassium chloride increases in the electrolytic solution before standing, the maximum voltage decreases, but in each example according to the present invention, the voltage when no potassium chloride is added has almost been maintained. On the other hand, in the electrolytic solution after being left unused, the voltage drop becomes even greater in the conventional example, but in the example, the same voltage is maintained as in the characteristics before being left unused. This phenomenon in the conventional example listed in Table 3 is
As mentioned above, the major cause is the change in quality of the driving electrolyte, that is, the decrease in the electrolyte concentration due to the amidation reaction. By the way, in the present invention, such a phenomenon can be prevented by suppressing the amidation reaction, and the fact that aluminum has almost no effect on the maximum voltage even if potassium chloride is added to the electrolytic solution before standing is This means that the film repairability of the electrolyte on foil is less likely to be interfered with by halides than in conventional examples, and this can be fully expected to prevent corrosion caused by halides when used in capacitors as an electrolyte for driving electrolytic capacitors.

[Scope of practical application of the invention]

In addition, in the components of the electrolytic solution according to the present invention, water has a content of 0.1 to 30%
The amount is preferably 0.1 wt%, and the film repairability of the cone capacitor element decreases, and the amount exceeding 30 wt% reduces the service life. In addition, the electrolyte is 0.5 to 30 wt%
The amount of
If it exceeds t%, the withstand voltage decreases and neither is of practical use.

Patent applicant: Elna Co., Ltd. Q-

Claims (1)

[Claims] (1) In an electrolytic solution for driving an electrolytic capacitor consisting of one or more of alkylammonium salts, phenyl ammonium salts, or cycloalkylammonium salts of carboxylic acid, an organic polar solvent, and water, the organic polar solvent is ethylene glycol. , polyhydric alcohols such as diethylene glycol, glycol ethers such as ethylene glycol monomethyl ether, ethers such as ethylene glycol monomethyl ether acetate, lactones such as γ-butyrolactone, and amines such as dimethylformamide. An electrolytic solution for driving an electrolytic capacitor characterized by comprising a mixed organic polar solvent.