JPS6267809A - Electrode foil 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 electrode foil for an aluminum electrolytic capacitor.

Conventional technology This type of conventional aluminum electrolytic capacitor is constructed by winding aluminum foil, which has been electrolytically etched in an electrolytic solution containing chlorine ions to increase the effective surface area, and insulating paper, and impregnating it with a driving electrolytic solution. Ta.

Various methods of enlarging the surface area of electrode foils by electrolytic etching have been studied in the past, and saline is often used as an etching solution for low pressure applications of 10 oV or less. In the method using a saline solution, direct current or pulsed current is used industrially as the current waveform.

JP-A-57-132322 discusses a method of etching using pulsed current in a saline solution.

In U.S. Pat. No. 4,437,955 and the drawings, after etching with alternating current in hydrochloric acid as a pretreatment,
A method of performing direct current etching in a saline solution is being considered.

Problems to be Solved by the Invention However, these methods have the disadvantage that sufficient area magnification and strength cannot be obtained, and there are limits to miniaturization and cost reduction of aluminum electrolytic capacitors.

The present invention aims to solve these drawbacks and provide an electrode foil with a high wavefront magnification.

Means for Solving the Problems In order to solve these problems, the present invention takes steps 2 to 8.
% hydrochloric acid by applying alternating current, and
It was constructed by etching by applying a pulse current in a 26% saline solution.

For production The effect of this technical means is as follows.

The aluminum foil used for the electrode foil is made with rollability after scouring. Therefore, a lot of rolling oil is attached to the surface. AC etching in hydrochloric acid has the effect of removing rolling oil and is effective as a degreasing pretreatment. As a result, the two surface conditions become uniform, so the number of etch bit generation points in the subsequent saline solution increases, and a wavefront magnification in etching can be obtained.

However, the effect of pre-degreasing by alternating current etching in hydrochloric acid is much greater when pulsed current is used than when direct current etching is carried out in a saline solution. The reason is as follows. In the DC method, the first etch bit that is generated advances linearly until the end of etching, so that etch pit generation points are generated at the time of current rush when current begins to flow.

However, in the pulse current method, the current is repeatedly turned on and off. Since new etch pits are created while the current is on, a larger number of etch pits are formed on the surface of the aluminum foil than in the direct current method.

Therefore, the degreasing effect of AC etching pretreatment is more effective with the pulsed current method, which generates a larger amount of etch bits on the surface.

Example Two embodiments of the present invention will be described below.

[Example 1] As is clear from Table 1, the combination of the AC etching pretreatment and the pulsed current method resulted in a much higher wavefront magnification than conventionally expected.

Table 1 [Example 2] Table 2 shows a comparison of the wavefront magnification depending on the type of aluminum foil between the conventional example and the example of the present invention.

Table 2 In the conventional NaCl direct current method, 60
There is a difference in the wavefront magnification of %, but in the present invention, it is soft.

High wavefront magnification can be obtained with both hard materials. The reason for this is that the etch bit generation points in the DC method are formed on the rolled structure, which is unique to hard materials, whereas in the pulsed current method, many etch pits are formed on the surface by turning on and off the current. It does not depend on the presence or absence of an organization. As a result, since a soft foil can be used according to the present invention, an electrode foil with strong bending strength can be manufactured.

Effects of the Invention As described above, according to the present invention, it is possible to improve the wavefront magnification and bending strength of the electrode foil, and as a result, the aluminum electrolytic capacitor can be made smaller and its cost can be reduced.

Claims (2)

[Claims] (1) Electrode for aluminum electrolytic capacitor constructed by etching the surface of aluminum foil by applying alternating current in 2-8% hydrochloric acid and etching by applying pulse current in 10-26% salt solution. foil. (2) Etching dissolution amount in hydrochloric acid is 0.2 to 1 mg/
The electrode foil for an aluminum electrolytic capacitor according to claim 1, which has a thickness of cm^2.