JPS62124727A - Driving electrolyte for 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 the Invention The present invention relates to an electrolytic capacitor, and more specifically, to an improvement in an electrolytic solution for driving an aluminum electrolytic capacitor (hereinafter simply referred to as an electrolytic solution).

BACKGROUND OF THE INVENTION Conventionally, as this type of electrolytic solution, one in which ethylene glycol is used as a main solvent and ionogen is dissolved therein is known. In addition, in order to improve various properties, for example, as shown in Japanese Patent Application Laid-open No. 7564/1983, an amidite salt of maleic acid is dissolved in a solvent mainly composed of γ-butyrolactone. An electrolytic solution containing a solute is used. On the other hand, in recent years, in order to attach electronic components to printed circuit boards, lead wire portions are often mechanically bent and used, but such processing has a significant effect on leakage current of aluminum electrolytic capacitors. Generally, aluminum electrolytic capacitors use a dielectric oxide film for the electrode that serves as the anode.

Due to the nature of this film, a small amount of leakage current is unavoidable, but apart from this, the leakage current at the joint between the anode electrode and the lead-out aluminum tab increases significantly when even a slight mechanical stress is applied. This is because the pull-out aluminum tab is connected to the lead wire part, and the impact from bending the lead wire part is directly transmitted to the anode electrode, damaging the film, and the electrolyte can repair the film. Even with this effect, it does not return to the level before the bending process in a short period of time, and furthermore, there is a drawback that the variation in leakage current value increases compared to before the process. Conventionally, as a method for improving this drawback, addition of resorcylic acid has been known as shown in Japanese Patent Publication No. 60-3767, but sufficient effects have not been obtained.

Problems to be Solved by the Invention The present invention solves these conventional drawbacks, and provides an electrolytic capacitor driving device that reduces the leakage current of an aluminum electrolytic capacitor and suppresses its variation by further improving the chemical composition. The purpose is to provide an electrolyte.

Means for Solving the Problems In order to solve the above problems, in the present invention, γ-
Borodigentisic acid or its salt is added to an electrolytic solution in which an amidite salt of maleic acid is dissolved as a solute in a solvent mainly composed of butyrolactone.

It is thought that this composition improves the chemical formation ability of the electrolytic solution compared to the case where resorcylic acid is added, and repairs the dielectric oxide film damaged by the bending of the lead wire portion more quickly.

Example Examples according to the present invention will be described below.

An electrolytic solution consisting of 100 parts by weight of γ-butyrolactone, 10 parts by weight of maleic acid, and 9 parts by weight of triethylamide (Conventional Example 1), an electrolytic solution to which 2 parts by weight of resorcylic acid was added (Conventional Example 2), and borodigentisic acid. Using each of the electrolytes (examples of the present invention) to which 3 parts by weight were added, the rated power was 50 W, V,
A 10 μF aluminum electrolytic capacitor was manufactured, and Table 1 shows the results of comparing the leakage current suppression effect before and after processing the lead wire portion.

(Left below) Figure 1 shows the high-temperature load characteristics of an electrolytic capacitor using the above electrolyte. FIG. 2 shows the leakage current change ratio and capacity change rate due to changes in the amount of borodigentisic acid added.

As is clear from Table 1, by adding porodigentinic acid, the leakage current value after lead wire processing can be significantly reduced compared to the conventional example. Furthermore, as is clear from FIG. 1, life characteristics can also be more stable than in the conventional example.

Furthermore, as is clear from Fig. 2, the change ratio of leakage current before and after bending the lead wire portion with respect to changes in the amount of addition is as follows:
The addition amount of borodigentisic acid is 0.01 parts by weight per 100 parts by weight of the solvent. It is preferable to use it in a range of 10 parts by weight.

Effects of the Invention As described above, according to the present invention, the leakage current of an aluminum electrolytic capacitor can be reduced and its fluctuation can be suppressed compared to conventional electrolytic solutions, which is of great industrial value.

[Brief explanation of drawings]

Figure 1 a/%/c compares the changes in capacitance change rate, tangent of loss angle, and leakage current over time at high temperatures for aluminum electrolytic capacitors using conventional electrolytes and electrolytes of the present invention. The characteristic diagrams shown in FIGS. 2a and 2b are characteristic diagrams showing a comparison of the leakage current change ratio before and after lead wire processing and the capacity change rate after a high temperature load test due to changes in the amount of borodigentisic acid added.

Claims (2)

[Claims] (1) An electrolytic solution for driving an electrolytic capacitor, characterized in that an amidite salt of maleic acid is dissolved as a solute in a solvent mainly composed of γ-butyrolactone, and borodigentisic acid or a salt thereof is added and dissolved therein. (2) Borodigentisic acid or its salt in a solvent of 10
The electrolytic solution for driving an electrolytic capacitor according to claim 1, wherein 0.01 to 10 parts by weight is added to 0 parts by weight.