JPS63213918A - Electrolyte for driving electrolytic capacitor - 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 that has excellent low-temperature characteristics and is stable at high temperatures.

Conventional technology An electrolytic capacitor has a structure in which a capacitor element is made by winding chemically etched aluminum anode foil and cathode foil with separator paper interposed between them, impregnated with electrolyte, and this element is housed in an aluminum case with a rubber backing. Conventionally, it is known to use an electrolytic solution containing a mixed solvent of ethylene glycol and water and an ammonium salt of carboxylic acid as a solute.

Problems to be Solved by the Invention An electrolytic solution containing an ammonium salt of carboxylic acid as a solute in a mixed solvent of ethylene glycol and water has an increased viscosity at low temperatures, which deteriorates the low-temperature characteristics of the capacitor.

Furthermore, during a load test in a high-temperature atmosphere, the anodic oxide film and cathode foil of the capacitor reacted with water to generate hydrogen gas, which increased the pressure inside the capacitor and led to its destruction.

Means for Solving the Problems The present invention solves the above-mentioned problems by using 95 to 50 wt% of T-prolactone, methanol or ethanol 2.
~20w t%, ethylene glycol 3~30w t9
For driving an electrolytic capacitor, characterized in that 5 to 30 wt % of a metal salt of borodisalicylic acid and 1 to 10 wt % of a metal salt of maleic acid are dissolved in a mixed solvent consisting of three components having respective weight ratios of 6. It is an electrolyte.

Function: By dissolving metal salts of borodisalicylic acid and maleic acid in a mixed solvent of γ-butyrolactone, methanol or ethanol, and ethylene glycol as the electrolyte for aluminum electrolytic capacitors, the electrolyte has a relatively low resistivity even at low temperatures. Electrolytic capacitors using this material have suppressed capacitance reduction and jan δ increase, and also exhibit stable characteristics in reliability tests such as high-temperature load tests.

Example Hereinafter, specific examples of the present invention will be described.

Table 1 shows examples of electrolytes of the present invention (sample symbols A, B
, C, D) and a conventional electrolytic solution (sample symbol E) as a comparative sample.

Table 2 shows the low-temperature characteristics of capacitors using the above electrolytes A, B, C, D, and E. The sample capacitors are all aluminum electrolytic capacitors with a rating of 35 WV and 220 μF.

Table 3 shows the results of a high temperature load life test in a 105 degree atmosphere of capacitors using the above electrolytes A, B, C, D and E.

As is clear from the above examples, electrolysis is performed by dissolving a metal salt of borodisalicylic acid and a metal salt of maleic acid as solutes in a mixed solvent consisting of the three components of γ-butyrolactone of the present invention, methanol or ethanol, and ethylene glycol. Aluminum electrolytic capacitors using liquid have significantly improved low-temperature characteristics and high-temperature load life. The results of various experiments have shown that when borodisalicylic acid is less than 5 wt%, the specific resistance of the electrolytic solution is high, and when the amount exceeds 30 wt%, precipitation occurs at low temperatures. Similarly, when the metal salt of maleic acid is less than 1 wt%, the specific resistance of the electrolyte becomes high.
If the amount exceeds 10 wt%, precipitation will occur at low temperatures. Furthermore, if methanol or ethanol is less than 2 wt%, the specific resistance of the electrolyte at low temperatures will be high (and if the amount exceeds 20 wt%, the vapor pressure will be high at high temperatures, and if the capacitor is left in a high temperature atmosphere, the internal pressure will increase. If ethylene glycol is less than 3 ht%, it will not be possible to dissolve the metal salt of maleic acid.
If the amount exceeds 0wt%, the viscosity of the electrolytic solution at low temperatures becomes high (and the specific resistance at low temperatures becomes high.Also, although potassium salts were shown in the above examples, calcium salts,
Similar results were obtained with the sodium salt and a mixture of these three types of salts, and similar results were obtained through repeated experiments by varying the mixing ratio of each solvent and solute within limits.

Effects of the Invention As described above, the electrolytic solution for driving an electrolytic capacitor according to the present invention has 1. A highly reliable electrolytic capacitor that maintains extremely stable characteristics can be obtained.

Claims (3)

[Claims] (1) For a mixed solvent consisting of 95 to 50 wt% of γ-butyrolactone, 2 to 20 wt% of methanol or ethanol, and 3 to 30 wt% of ethylene glycol,
An electrolytic solution for driving an electrolytic capacitor characterized by dissolving metal salts of borodisalicylic acid and maleic acid. (2) The electrolysis for driving an electrolytic capacitor according to claim 1, characterized in that one or more of potassium salt, calcium salt, and sodium salt is dissolved as the metal salt of borodisalicylic acid and maleic acid. liquid. (3) The metal salt of borodisalicylic acid is 5 to 5% of the mixed solvent.
3. The electrolytic solution for driving an electrolytic capacitor according to claim 2, wherein 30 wt% and 1 to 10 wt% of a metal salt of maleic acid are dissolved.