JPS592371B2 - Manufacturing method of electrolytic capacitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an electrolytic capacitor in which the ends of cathode foil are laminated.

Generally, in an electrolytic capacitor in which the ends of cathode foils are laminated, the inductance and impedance of the capacitor tend to inevitably increase and have a negative effect on performance, so it is necessary to reduce these as much as possible.

For this reason, conventional publications such as Japanese Patent Publication No. 38-7678 and Japanese Patent Publication No. 43
Proposals such as the one in Publication No. 18014 have been made.

In other words, in the former case, the cathode foil is made to protrude over the end face of the capacitor element and is mechanically crushed. However, since it is a mechanical contact, it is incomplete, and the impedance and inductance of the capacitor change due to vibration, resulting in desired characteristics. There is a drawback that it cannot be obtained.

In particular, when used in audio equipment, the third harmonic distortion is large and the sound quality is poor.

In addition, in the latter method, the cathode foil is pressed against the end face of the capacitor element, and molten metal is sprayed on the pressed part, but the sprayed metal powder is suspended in the electrolyte during the electrolyte impregnation process. Since it is impregnated inside the capacitor element, it has the fatal disadvantage of short circuiting.

The present invention has been made in view of the above-mentioned drawbacks, and involves winding at least a cathode foil protruding from the end face of a capacitor element, mechanically crushing it to make it flat, and then laser welding the cathode foil. A method for producing an electrolytic capacitor that reduces contact resistance, impedance, and inductance by completely welding and laminating the protruding portion, and can be used in audio equipment to improve sound quality and reduce third-order harmonic distortion. We aim to provide the following.

Detailed Description of the Invention Below, as shown in Figure 1, an anode foil made of a valve metal such as aluminum whose surface has been roughened to expand its surface area and an anodic oxide film formed thereon, and an aluminum plate facing above the anode foil with a spacer interposed therebetween. The cathode foil, which constitutes the capacitor element 1 by overlapping the cathode foil made of the like, has one end surface protruding from the spacer, and has been roughened and/or anodized as required. In this way, the cathode laminated portion 2 is formed.

3 is a lead terminal connected to the anode foil and the cathode foil.

After the cathode layered portion 2 is flattened by mechanically crushing it, welding 4 is performed by laser beam irradiation to completely melt and bond the cathodes of each wound layer.

By completely melting and layering the cathode laminated portion 2 by laser irradiation in this manner, impedance and inductance are reduced, third harmonic distortion is reduced, and an electrolytic capacitor with good sound quality can be obtained for use in audio equipment.

After laser beam irradiation, the device is impregnated with a driving electrolyte using a known method, and then stored in a container and sealed.

Further, as shown in FIG. 2, anode foil 5. The cathode foils 6 may be stacked so as to be offset from the end faces of the spacers 7, and then wound to form a non-inductive structure capacitor element 1 as shown in FIG.

In this case, an anode layer 8 is provided on both the anode and the cathode.
and a cathode condensation layer 2 is formed, but this consolidation layer 8゜2
are welded by laser beam irradiation.

Then, a crown-shaped terminal plate 9 may be brought into contact with the consolidated layer portions 8, 2 to lead out terminals 10 on both end surfaces.

Furthermore, although the above explanation deals with a single capacitor element, it can also be applied to a multi-element type electrolytic capacitor element in which multiple anode foils are arranged at regular intervals and a common cathode foil is laminated and wound through a spacer. Of course.

Next, a comparison of impedance frequency characteristics and third harmonic distortion characteristics between Example A of the present invention and conventional Reference Example B are shown in FIGS. 4 and 5.

In Example A, the input voltage to the cathode layer was 580 V, and the number of irradiations was I.
p () odorless) , , NO7 less rate 2.5p
pS, defocus amount +14mm, condenser lens f=50
The welding was performed by irradiating a laser beam under the condition of 1.0 mm, and in Reference Example B, a concave groove was mechanically formed by strongly pressing the cathode layer.

Both are aluminum electrolytic capacitors with a rating of 50WV-DC-100μF.

As is clear from FIGS. 4 and 5, Example A is superior to Reference Example B in both impedance characteristics and third harmonic distortion characteristics, and it can be seen that there is a significant difference.

As described in detail above, according to the present invention, at least the cathode foil is made to protrude from the end face of the capacitor element, is wound, is crushed flat, and is then welded by laser beam irradiation to form a layered portion, thereby increasing the impedance. Furthermore, it is possible to provide a method of manufacturing an electrolytic capacitor having a stable characteristic with low third harmonic distortion and having a small inductance and used in audio equipment.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a capacitor element according to the manufacturing method of the present invention, FIG. 2 is an exploded perspective view showing a capacitor element according to another embodiment, and FIG. 3 is an electrolytic capacitor made of the capacitor element shown in FIG. 2. FIG. 4 is a curve diagram showing a comparison of impedance characteristics, and FIG. 5 is a curve diagram showing a comparison of third harmonic distortion characteristics. DESCRIPTION OF SYMBOLS 1...Capacitor element, 2...Cathode layered part, 3...Output terminal, 4...Welding point, 5...Anode Foil, 6...Cathode foil, 7.
...Spacer, 8...Anode lamination section, 9.
...Crown-shaped terminal plate, 10...Terminal.

Claims (1)

[Scope of Claims] 1. An electrolytic capacitor characterized in that at least a cathode foil is made to protrude from the end face of a capacitor element, is wound, is crushed flat, and is then welded by laser beam irradiation to form a bonded part. manufacturing method. 2. The method of manufacturing an electrolytic capacitor according to claim 1, wherein the layered portion is formed on both the cathode and the cathode. 3. The method of manufacturing an electrolytic capacitor according to claim 2, characterized in that the crown-shaped terminal plate is still in contact with the laminated portion to lead out the electrodes.