JPH01321623A - Manufacture of electrolytic capacitor - Google Patents

Abstract

PURPOSE:To enable capacity to be increased as compared with the conventional products, and enable material reduction in the case where a capacitor with the same capacity is manufactured by irradiation of lasers on the lead buried part of a conventional pressed compact in a low oxygen atmosphere, and then sintering it at a specific temperature. CONSTITUTION:A pressed compact 1 that the lead wire 1a of valve acting metal is buried is formed, and laser beams 2 by YAG pulse laser are applied to that lead buried part so as to fuse and unite the lead wire 1a and a part of the pressed compact 1 in the vicinity. And the pressed compact 1 is sintered at 1200 deg.C-1600 deg.C in vacuum. Hereby, as compared with a conventional capacitor, 40% capacity-up can be realized at maximum in the same size, and in the case that a capacitor with the same capacity is to be obtained, 40% material reduction at maximum becomes possible.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing an electrolytic capacitor.

2. Description of the Related Art Conventional electrolytic capacitors generally have a structure as shown in FIG. Buried and pressure molded to -1600℃~
The electrode body 12 is formed by sintering at a temperature of 2000°C. Next, the surface of the electrode body 12 is anodized to form a dielectric oxide film 1.
3 is formed, and then impregnated with a semiconductor mother liquor such as manganese nitrate, this is thermally decomposed to form a manganese dioxide layer 14, and then a graphite layer 15 and a conductive paint layer 16 are formed, and a lead wire 11 is formed. The external lead 17 is pulled out from the conductive paint layer 16 by soldering, etc., and the exterior resin 18 is pulled out.
Or it is sealed in a metal case and made into a finished product.

In electrolytic capacitors, the anode body sintering temperature is an important factor in determining the capacity and weight. FIG. 4 shows the relationship between the anode body sintering temperature and the capacitor CV value.

As can be seen from FIG. 4, the lower the sintering temperature, the higher the Cv value of the capacitor. In other words, in order to obtain a capacitor with high capacity, it is advantageous to perform sintering at a low temperature. Further, FIG. 5 shows the relationship between the anode body sintering temperature and the anode body crushing strength. As can be seen from FIG. 5, when the sintering temperature exceeds 1000°C, the crushing strength of the anode body increases.

It can be seen that the bond between the metal powder and the metal powder progresses at a temperature of 91,200° C. or higher. This means that the sintering temperature of the anode body can be lowered to 120C).
This makes it possible to obtain a capacitor with high capacity.

Problems to be Solved by the Invention On the other hand, as the sintering temperature decreases, the bond between the anode body and the lead becomes weaker. FIG. 6 shows the relationship between anode body sintering temperature and lead pull-out strength. As can be seen from FIG. 6, when the sintering temperature exceeds 1600°C, the pull-out strength increases. It can be seen that the bonding between the metal powder and the lead does not proceed at a temperature of 1000 degrees. For this reason, the current anode body with embedded leads has a structure that cannot be sintered at temperatures below 1600°C.

It is an object of the present invention to solve such problems and to increase capacity.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention irradiates the base of the anode lead buried part of the pressure molded body with a laser to melt and bond the lead and a part of the molded body, and then゜℃〜1600℃
Vacuum sintering was performed at a temperature of .

Effect By adopting the above configuration, the capacitance can be increased by up to 40% with the same size compared to conventional capacitors, and when trying to obtain a capacitor with the same capacity, the material can be reduced by up to 4Q%. It becomes possible.

Embodiment Hereinafter, one embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows an electrolytic capacitor element of the present invention.

First, as in the conventional method, a pressure molded body 1 is formed in which a valve metal lead wire 11L is embedded, and a YAG
A laser beam 2 from a pulsed laser is irradiated to melt and bond the lead wire 1a and a portion of the pressure molded body 1 around the lead wire 1a. FIG. 2 shows an electrolytic capacitor of the present invention. The press-formed body 1 is sintered in vacuum at 1000°C to 1600°C to form an electrode body 3, and a dielectric film 4, a manganese dioxide layer 5, a graphite layer 6, and a conductive paint layer 7 are deposited on the surface. Next, the external leads 8 are provided by soldering, etc., and the resin 9
It becomes a υ electrolytic capacitor by sheathing it with .

Next, a specific example will be described in comparison with a conventional example. Second
As shown in the picture, weight 40cm, diameter 1.8mm, length 2,4
A laser beam 2 from a YAG pulse laser of 3.0 joules/hulls was applied to the lead-embedded part of the pressure molded body 1 in which a lead wire with a wire diameter of s-omm was embedded in m1In in an oxygen partial pressure of 10 torr in vacuum. The lead wire 1a and a part of the press-molded body 1 in the vicinity thereof are irradiated with a high power and melted and bonded, and then sintered at a vacuum degree of 10 to 1 torr and a temperature of 1200 degrees Celsius to form an electrode body 3. After forming a primary dielectric film 4, a manganese dioxide layer 5, a graphite layer 6, and a conductive paint layer a on this electrode body 3, the anode lead wire 1aK
The anode lead is connected by welding, and the cathode external lead is connected to the conductive paint layer 7 by soldering.
Connect cable 8, apply exterior resin, and set the rating to 16v10.
A μF product was obtained. In addition, the conventional product does not require laser irradiation.
The electrode body 3 was manufactured under the same conditions except that the electrode body 3 was sintered at 600°C. Product characteristics are shown in Table 1.

Table 1 Product Characteristics Although the loss and leakage current of the product manufactured according to the present invention are the same as those of conventional products, the capacity is increased by approximately 40%, confirming that the capacity is improved. It can also be confirmed that if the product of the present invention is manufactured to the same capacity as the conventional product, the main material of the capacitor can be reduced by 40%, which is an effect of material reduction.

Effects of the Invention As described above, after laser irradiation is performed on the lead-buried portion of a conventional pressure-molded body in a low oxygen atmosphere,
By sintering at 0°C, it is possible to increase the capacity by up to 40% compared to conventional products, and when manufacturing capacitors with the same capacity, it is possible to use up to 40% less material. The practical effects of the invention are very large.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a method of manufacturing an electrolytic capacitor according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing an electrolytic capacitor manufactured by the method of the present invention, and FIG. Figure 4 is a characteristic diagram showing the relationship between anode body sintering temperature and capacitor CV value, Figure 5 is a characteristic diagram showing the relationship between anode body sintering temperature and anode body crushing strength, and Figure 6 is a characteristic diagram showing the relationship between anode body sintering temperature and anode body crushing strength. FIG. 3 is a characteristic diagram showing the relationship between lead pull-out strength. DESCRIPTION OF SYMBOLS 1... Pressure molded body, 1a... Lead wire, 2... Laser beam, 3... Electrode body. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 Figure 4! 2θo taoo t4oo ts
aρ ttao tqoty temperature (0ri 5th illustration: A degree Cc)

Claims (1)

[Claims] A metal powder with a valve action such as tantalum, aluminum, niobium, etc. is pressure-molded, a metal member with a valve action is buried as an anode lead, and the base of the lead is irradiated with a laser to form a part of the lead and the molded body. 1. A method for manufacturing an electrolytic capacitor, which comprises melting and bonding and then vacuum sintering at a temperature of 1200°C to 1600°C.