JPS6041449B2 - How to reconstitute electrolytic capacitors - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for reconstitution of electrolytic capacitors.

For example, solid electrolytic capacitors are manufactured through the following steps.

First, as shown in Figure 1, a porous capacitor element is formed by press-molding and sintering a metal powder that has the same valve action on the lower end of the anode lead made of a metal wire that has a valve action, such as tantalum or titanium. form 2. Next, as shown in FIG. 2, the upper ends of the plurality of anode leads 1 each having a capacitor element 2 are electrically connected and fixed to one metal plate 3 at equal intervals by welding or the like. Two tie bar parts 4
get. Next, the plurality of tie bar parts 4 are arranged to form each capacitor element 2 for chemical conversion (
immersed in an electrolytic solution 5 such as a phosphoric acid aqueous solution (for anodizing),
A predetermined positive voltage is applied from the metal plate 3 to the capacitor element 2 via the anode lead, while a negative voltage is applied to the cathode plate 6 immersed in the electrolytic solution 5 to perform chemical conversion treatment. Then, an oxide film, which is a compromise material, is formed on the inner and outer surfaces of the porous capacitor element 2. For example, a capacitor element made of sintered tantalum (Ta2 in the case of 2'
An oxide film of No. 05 is formed. Next, this capacitor element 2 is pulled up from the electrolytic solution 5, and then, as shown in FIG. 4, it is immersed in a semiconductor mother liquor, for example, a manganese nitrate solution 7, so that the inside is sufficiently impregnated, and then pulled up and thermally decomposed. and,
By repeating the impregnation-pyrolysis process several times, a semiconductor layer of manganese dioxide or the like is formed on the oxide film.
By the way, the heat during this thermal decomposition deteriorates the oxide film and causes defects, so after several heat treatments, capacitor element 2 is subjected to chemical conversion treatment (re-formation) again as shown in Figure 3. to repair the oxide film. After performing thermal decomposition and re-formation several times, an electrode lead layer such as a graphite layer or a silver base layer is formed on the semiconductor layer, and the external lead of the cathode is soldered to this dragon electrode lead layer. do. By the way, since the reconstitution of the capacitor elements 2 is carried out by immersing a plurality of capacitor elements 2 in the electrolytic solution 5 at once as shown in FIG. 3, the following problem occurred. . In other words, although the capacitor element 2 is made by pressurizing metal powder such as tantalum that has a valve action and condensing it to a purity close to 100%, minute impurities are inevitably mixed in, and the current during re-formation is concentrated here. It may be destroyed. Furthermore, the connection portion of the capacitor element 2 with the anode lead may be mechanically damaged by an external impact, and there is a risk that current will be concentrated there. In addition, cracks may occur partially in the semiconductor layer of the capacitor element 2 due to thermal strain caused by thermal decomposition, and current may concentrate in the cracked portions. If the current concentrates locally during re-formation due to various causes such as these, for example, if the semiconductor layer is manganese dioxide, the oxide film in the area where the current is concentrated will be destroyed and ionized manganese will fly out, and some of it will be absorbed into the cathode plate 6. However, the remaining part collides with the adjacent capacitor element 2, which may turn the adjacent capacitor element 2 into a defective product even if it is a good product. Furthermore, the higher the re-forming voltage, the higher the incidence of defective products in the capacitor element 2 during such re-forming, so conventionally re-forming was carried out at a safe low voltage in order to minimize the occurrence of defective products. Ta. However, since the re-forming voltage and the thickness of the oxide film are in a substantially proportional relationship, there is a problem in that when the re-forming voltage is low, the withstand voltage of the capacitor deteriorates. The present invention solves the above-mentioned problems caused by the re-formation of secondary vessels by providing a partition wall between each capacitor element during re-formation, so that a capacitor element which has become defective due to current concentration can be separated from the adjacent capacitor element. A reconstitution method for protecting capacitor elements is provided. Hereinafter, the present invention will be explained with reference to embodiments of the drawings. In the present invention, after chemical conversion treatment and thermal decomposition treatment are performed on the capacitor element 2 of the tie bar part 4 shown in FIG. Perform reconversion treatment.

This re-forming device 8 has an electrolytic layer 9 filled with a re-forming electrolyte 10 and a cathode plate 11, and an insulating partition sheet 12 made of Teflon, paper, plastic, etc. stretched along the surface of the electrolyte 10. It is. This partition sheet 12 has, for example, cross-shaped cuts 13, which are slightly larger than the outer diameter of the capacitor elements 2, at a plurality of locations arranged in accordance with the arrangement of the capacitor elements 2 of the tie bar parts 4. This reconversion device 8 performs reconversion by first lowering a plurality of tie bar parts 4 from above the bulkhead sheet 12, pressing each capacitor element 2 into each notch 13 of the bulkhead sheet 12 to open the notch 13, and then As shown in the figure, the lower end of the capacitor element 2 is immersed in an electrolytic solution 10'. At this time, bulkhead sheet 1
When the condenser element 2 is inserted, the four peripheral surfaces of the notch 13 of No. 2 are bent downward while in contact with the outer circumferential surface of the condenser element 2, thereby forming an enclosure for the condenser element 2, a partition wall 12a between the condenser element 2 and the adjacent condenser element 2, etc. 12b, 12
c, 12d. Also, since the capacitor element 2 is porous, if the lower end is immersed in 10' of electrolyte, the electrolyte 1
0 penetrates the inner and outer surfaces of the capacitor element 2 by capillary action, and the entire surface of the capacitor element 2 is covered with electrolyte 10.
The situation is the same as being immersed in water. Then, a reforming voltage is applied to the metal plate 3 and cathode plate 11 of the tie bar part 4, and each capacitor element 2 is reformed all at once. During this reformation, for example one capacitor element 2'
If the current is concentrated in a part of the capacitor element 2', resulting in a defective product, ions such as manganese are released from the capacitor element 2' as described above. However, in the case of the present invention, the defective capacitor element 2' is connected to the partition walls 12a, 12b, 12
Surrounded by c and 12d, this capacitor element 2
'The capacitor element 2 next to ' is also another partition wall 12a,
12b, 12c, and 12d, the ions from the defective capacitor element 2' are adsorbed by the cathode plate 11, and the adhesion of ions to the adjacent capacitor element 2 is prevented by flowing the electrolyte 10. If you do this, it will be done more effectively. FIG. 9 shows an embodiment of a reconversion device 8' in which a lattice-shaped insulating partition frame 14 is immersed in the electrolytic solution 10 with a portion thereof exposed in place of the partition sheet 12.

In this case, the capacitor element 2 is inserted into each frame portion 15 of the partition frame 14, and the lower end of the capacitor element 2 is immersed in an electrolytic solution. Furthermore, the electrolytic solution 10 is allowed to flow by utilizing the gap between the partition wall frame 14 and the bottom surface of the electrolytic cell 9. The device for carrying out the present invention is not limited to the above-mentioned example. For example, the partition frame may be made of metal and also serve as a negative electrode plate.

Alternatively, the inside of the electrode tank may be divided into independent re-forming chambers using this type of partition frame, and the cathode plate and electrolyte may be placed in each re-forming chamber to re-form the capacitor elements independently. good. Furthermore, the capacitor element can be made of plate material, wire material, etc. in addition to metal powder. As explained above, according to the present invention, since a partition wall is provided between adjacent capacitor elements and reconstitution is performed, there is a problem that a defective capacitor element adversely affects adjacent capacitor elements and becomes a defective product. This decreases the number of capacitors, improves the rate of non-defective capacitors, and makes it possible to reduce costs.

Further, by reducing the above-mentioned troubles, the voltage applied during re-forming can be increased, and therefore the withstand voltage of the capacitor can be improved.

[Brief explanation of the drawing]

1 to 4 are partially sectional side views showing each step of a conventional manufacturing method of an electrolytic capacitor, and FIG. 5 is a side sectional view showing an example of an apparatus for carrying out the reconstitution method according to the present invention. FIG. 6 is a partial plan view of the device shown in FIG. 5, FIG. 7 is a side sectional view of the device shown in FIG. FIG. 9 is a partial sectional view taken along the line A--A in FIG. 2...Capacitor element, 8,8'...Reformation device, 1
0... Electrolyte, 12... Partition wall (sheet), 12a,
12b, 12c, 12d... partition wall, 14... partition wall (
frame). Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9

Claims (1)

[Claims] 1. When performing reconversion treatment on multiple capacitor elements that are made of metal members with valve action and have oxide films and semiconductor layers formed on their surfaces, there is A method for reconstitution of an electrolytic capacitor characterized by providing a partition wall.