JPS5833821A - Method of producing aluminum solid 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 The present invention relates to a method of manufacturing an aluminum solid electrolytic capacitor in which masking is performed using an acid-resistant tape during etching.

BACKGROUND ART Conventionally, methods of enlarging the surface area of electrodes by etching have been constantly studied as an important issue related to miniaturization of electrolytic capacitors.

By the way, in aluminum solid electrolytic capacitors, carbon dioxide is used instead of the electrolyte in the electrolytic capacitor.

Generally, this manganese dioxide is baked by thermal decomposition of manganese nitrate, but if the anode internal lead is etched at this time, the manganese nitrate creeps up and connects the anode internal lead and the anode external. Since even the connection points of the leads are covered with manganese dioxide, it can be said that consideration for preventing this is essential for aluminum solid electrolytic capacitors.

One method is to apply a paint such as an acid-resistant etching resist to the inner lead portion of the anode.

Although this method is simple, it lacks dimensional accuracy and completeness in preventing complete etching, and requires chemicals for removal, so there are concerns about contamination of the etched surface and changes in shape. Further, as a method of escaping the mask, there is a method of joining an etched aluminum electrode portion to another unetched aluminum anode outer lead.

However, there are few joining methods that offer good dimensional accuracy, good finish, and excellent productivity, and it is often difficult to choose one.

On the other hand, an example of masking that has relatively good dimensional accuracy, good finish, and excellent productivity is taping with acid-resistant tape. FIG. 1 is a diagram showing masking by this acid-resistant tape, in which an aluminum anode body 1 is held on an aluminum anode support 3 via an aluminum anode internal lead 2, and the aluminum anode internal lead 2 is sandwiched between acid-resistant tapes 4. It is masked so that it is included.

However, the disadvantage of this method is that when the thickness of the aluminum anode inner lead 2 becomes relatively thick (O, SW or more), as shown in FIG.
A gap 6 is likely to be formed between the aluminum anode inner lead 2 and the aluminum anode inner lead 2 due to poor adhesion. This results in
In particular, when chemical etching is used in combination, the masking effect is halved and the side surface 6 of the aluminum anode internal lead 2 is
is invaded.

The present invention is designed to solve these drawbacks, but does not prevent the masking acid-resistant tape 4 from being bent at a steep angle at the aluminum anode internal lead 2, or being stretched beyond its adhesion by the tension applied to the acid-resistant tape 4. It's inevitable because it is. Therefore, if you compare Figures 2a and 2b, the acid-resistant tape 4 in Figure 2A has fewer sharp bends, so the gap 6 is somewhat smaller, but the cross-sectional shape of the aluminum anode internal lead 2 is There are many areas that are affected.

Therefore, in the present invention, before masking the acid-resistant tape 4, the aluminum anode inner lead 2 is pressed and crushed by a mold, and its cross-sectional shape is formed into a shape consisting of oblique ridge lines. Compared to 4, the bending at a steep angle and the tension applied to the acid-resistant tape 4 are significantly reduced.

3a to 3d show the cross-sectional shape of the aluminum anode inner lead 2 obtained according to the present invention, and FIG. 4 shows a cross-sectional view of the aluminum anode internal lead 2 obtained by taping the lead shown in FIG. 3d.

6 pages Next, examples of the present invention will be given and the effects thereof will be described.

An aluminum anode internal lead with a cross section of width 2g and thickness 0.6H is masked with acid-resistant tape as shown in Figure 2a, and an aluminum anode interior whose cross section is crushed and molded as shown in Figure 3d. Two types of capacitors whose leads were masked with acid-resistant tape were subjected to conventional etching, chemical conversion, thermal decomposition, and reconversion cathode formation to form aluminum solid electrolytic capacitors, and the occurrence of leakage current defects was evaluated using 100 samples each. were measured. The results are shown in the table below.

As is clear from the results shown in this table, leakage current failures occur during the process of drawing out the anode external lead, drawing out the cathode external lead, and covering the aluminum anode with resin, which are the processes after the aluminum anode is removed before masking with acid-resistant tape. However, the product of the present invention almost never causes defects. This is thought to be because the difference in etching due to the difference between complete and incomplete masking creates a difference in the creep-up of manganese dioxide, making work in the assembly and exterior process difficult, and the method of the present invention can improve these processes. It has been proven how effective it is to facilitate.

As described above, according to the manufacturing method of the present invention, it is possible to completely prevent the aluminum anode internal lead from being etched with good dimensional accuracy, thereby easily obtaining an aluminum solid electrolytic capacitor with good leakage current characteristics. This is possible.

[Brief explanation of the drawing]

Figure 1 is a perspective view showing masking with acid-resistant tape, Figure 2a is a cross-sectional view of the taped part of the aluminum anode inner lead showing gaps that tend to occur when acid-resistant tape is pressed from one side, Figure 2 Figures 3a to 3d are cross-sectional views of the taped portion of the aluminum anode internal lead showing the gaps that tend to occur when acid-resistant tape is pressed from both sides. FIG. 4 is a cross-sectional view showing the aluminum anode internal lead of FIG. 3d taped with acid-resistant tape. 1...Aluminum anode body, 2...Aluminum anode internal lead, 3-...Aluminum anode support, 4...Acid-resistant tape Name of agent Patent attorney Toshio Nakao and 1 other person
1m1 12 Figure 3511 IA4FM

Claims (1)

[Claims] When selectively etching an aluminum anode body held on an aluminum anode support via an aluminum anode internal lead by masking with an acid-resistant tape, ``Before masking, the aluminum anode internal lead is etched so that the cross-sectional shape is a diagonal ridge line. 1. A method for manufacturing an aluminum solid electrolytic capacitor, the method comprising forming an aluminum solid electrolytic capacitor into a shape.