JPS6272108A - Electrolyte for aluminum 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 electrolyte for aluminum electrolytic capacitors.

BACKGROUND OF THE INVENTION Conventionally, an electrolytic solution for a 100 W V class aluminum electrolytic capacitor is an electrolytic solution in which adipic acid or a salt thereof is dissolved in a solvent mainly composed of ethylene glycol.

Problems to be Solved by the Invention In recent years, as aluminum electrolytic capacitors have become smaller and more reliable, there has been a demand for electrolytic solutions for aluminum electrolytic capacitors that have low specific resistance and are stable at high temperatures.

Conventionally, in order to lower the specific resistance, the mixing ratio of water in the electrolytic solution or the amount of solution II has been increased, but either method causes the problem that the spark voltage decreases and the usable voltage range is limited.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention aims to solve the above-mentioned problems by adding one or more of dibasic acids having 8 carbon atoms and an alkyl group in the side chain or their salts to a solvent mainly composed of ethylene glycol. This is an electrolytic solution for aluminum electrolytic capacitors, characterized in that two or more types are dissolved as solutes.

The resistivity of a working dibasic acid increases with the number of carbons between the two carboxyl groups. Similarly, stability at high temperatures and spark voltage increase with total carbon number. The dibasic acid having a side chain group in the electrolyte of the present invention exhibits a specific resistance corresponding to the number of carbon atoms between the carboxyl groups, and has high temperature stability and high spark voltage corresponding to the total number of carbon atoms, so it has a low ratio. Although it has a stable effect even at high temperatures, it is also stable at the working voltage.

In addition, when the number of carbon atoms is 7 or less, the spark voltage decreases and short banks occur during aging, and when the number of carbon atoms is 9 or more, the solubility in solvents mainly composed of ethylene glycol decreases.
Since it is not possible to dissolve the amount of solute required to lower the specific resistance, the number of carbon atoms is limited to 8.

Example Examples of the present invention will be described below.

Table 1 shows the electrolytic solution composition, the specific resistance value of the electrolytic solution at 30°C, and the anode foil with a rating of 250WV and 33μF.
A comparison of the spark voltage measured at 85°C by passing a current of 1 m^/piece through a product assembled after impregnating a conventional electrolyte and the electrolyte of the present invention into a capacitor element using V chemically formed foil. It is.

Table 2 shows the results using the electrolyte shown in Table 1 with a rating of 25WV, 2
Fabricate a 200μF aluminum electrolytic capacitor, 1
The results of a high temperature load test at 05°C for 1000 hours are shown.

Note that each characteristic is an average of 10 electrolytic capacitor samples, and the leakage current is the value 1 minute after application of the rated voltage.

Table 3 shows the constant 48160Wv using the electrolyte shown in Table 1.
, fabricated a 47 μF aluminum electrolytic capacitor, and
The results of a high temperature load test conducted at 5°C for 2000 hours are shown.

Note that each characteristic in Tables 2 and 3 shows the average value of 10 electrolytic capacitor samples, and the leakage current is the value 5 minutes after application of the rated voltage.

As is clear from the above examples, the electrolytic solution of the present invention has a resistivity equivalent to that of the conventional electrolytic solution (sample code A), and as a low-voltage product, it exhibits stable characteristics in a load test at 105'C. Furthermore, it has been demonstrated that even products rated at 160 W ■ exhibit stable characteristics.

As described above, the effects of the invention are as follows:
An electrolytic solution containing one or more dibasic acids or their salts as main solutes having 8 carbon atoms and an alkyl group in their side chains is suitable for use in aluminum electrolytic capacitors because it has high stability at high temperatures and is suitable for aluminum electrolytic capacitors. It can be used in a wide voltage range from low voltage to 160WV class without increasing the loss of electrolytic capacitors, and is of great industrial and practical value.

Claims (2)

[Claims] (1) 8 carbon atoms in a solvent mainly composed of ethylene glycol
An electrolytic solution for an aluminum electrolytic capacitor, characterized in that the main solute is one or more dibasic acids having an alkyl group in their side chains or their salts. (2) The above dibasic acid is 2,2-dimethyladipic acid,
The electrolytic solution for an aluminum electrolytic capacitor according to claim 1, characterized in that any one of 3,3-dimethyladipic acid, 2,3-dimethyladipic acid, and 3,4-dimethyladipic acid is used.