JPS62190829A - Manufacture of film capacitor - 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 the Invention The present invention relates to a method of manufacturing a film capacitor using a metallized film as a dielectric, and specifically relates to a method of drawing out external electrodes.

BACKGROUND OF THE INVENTION In recent years, there has been a remarkable development of small and highly reliable electronic components. In particular, precision welding technology has come to be positioned as an important processing technology in the development of electronic components.

In a film capacitor, after a metallized film is wound or laminated, a conductive layer is entirely formed by metal spraying on both edges where opposing internal electrodes (usually metal-deposited films) extend, and an external layer is applied to the conductive layer. A method for manufacturing a film capacitor is known, in which lead wires or lead frames used as electrodes are resistance welded and, if necessary, an exterior is provided.

Hereinafter, with reference to the drawings, the constituent elements of a conventional film capacitor and a method for drawing out external electrodes will be explained using a multilayer film capacitor as a representative example.

However, the same applies to wound film capacitors.

FIG. 3 is an enlarged view of a part of a cross section of a conventional multilayer film capacitor, showing its structure. In Figure 3, 1 is a dielectric film, 2゜3 is a dielectric film 1
The internal electrode 24 is an insulating part that insulates the internal electrodes 2 and 3, 6 is a protective film, and 6 is a conductive layer obtained by metal spraying.

FIG. 4 is a perspective view of a conventional multilayer film capacitor when external electrodes are drawn out. In Figure 4, 6
is a conductive layer, which has the same structure as that shown in FIG. 7 is an external electrode, and 8 welds the conductive layer 6 and the external electrode 7. This is a resistance welding electrode tip.

The method of drawing out the external electrodes of conventional film capacitors is as follows:
As shown in FIG. 4, the conductive layer 6 and the external electrode 7 are brought into close contact with each other by a resistance welding electrode tip 8, and current is applied to the conductive layer 6 while applying pressure.
A method of welding the external electrode 7t (resistance welding method) is used.

The problem that the invention seeks to solve However, in the method as described above, FIG.

As can be seen from Fig. 4, the weakest point regarding the stability of the bond between the internal electrode 2.3 and the conductive layer 6 is usually mechanical damage caused by the pressure applied during welding and thermal damage caused by the heat generated during welding. It is experimentally clear that this is due to damage, and the mechanical and thermal damage applied to the joint portion during welding deteriorates the dielectric loss tangent characteristics of the film capacitor, and in some cases.

It was known that this caused fluctuations in capacitor capacity.

Conventionally, as a means to reduce damage during welding, thick dielectric films have been used or the number of protective films has been increased. has become an obstacle. Also.

Weld spots during welding are also an obstacle in the production of small film capacitors.

In view of the above-mentioned problems, the present invention provides a method for drawing out external electrodes of a film capacitor that does not cause damage to the film capacitor element during welding and does not cause welding flashes.

Means for Solving the Problems In order to achieve this object, the method for manufacturing a film capacitor element of the present invention includes temporarily welding the conductive layer of the film capacitor element and the external electrode using a resistance welding method, and then using a laser +
The external electrode is welded to the conductive layer of the film capacitor element by completely melting the conductive layer and the external electrode using the method.

When the external electrode is brought into contact with the conductive layer of the working film capacitor and the external electrode is pressurized with a 5-resistance welding electrode chip and energized,
The conductive layer and the external electrode are welded by resistance heat generation at the contact portion between the conductive layer and the external electrode. In this case, the applied force, applied current 9
The current application time is related to welding strength and welding quality.

On the other hand, when an external electrode is brought into contact with the conductive layer and irradiated with a laser beam, the conductive layer and the external electrode are melted by the heat generated by absorption of the laser beam. In this case, the contact state between the conductive layer and the external electrode is related to laser welding strength and laser welding quality.

In the present invention, first, the resistance welding electrode tip has a resistance welding electrode tip with a degree (2ooy or less) necessary for the external electrode to come into contact with the conductive layer.
The external electrode is pressurized and energized. At this time, the applied current and application time may be such that the external electrode is slightly welded to the conductive layer (tensile shear strength is 600y or less).

Next, when the portion where the conductive layer and the external electrode are temporarily welded is irradiated with a laser beam, the portion irradiated with the laser beam locally generates heat, and the conductive layer and the external electrode are melted. As a result, welding of the external electrode is completed without damage to the film capacitor element and without welding cracks.

Embodiment One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the components for carrying out the method of the present invention. In FIG. 1, 6 is a conductive layer, 7 is an external electrode, and 8 is a resistance welding electrode tip, which is the same as the structure shown in FIG. 4. 9 is a laser generator, 10 is an optical system,
11 is a laser beam. The operation of the elements configured as described above will be explained below.

First, in the resistance welding electrode tip 8, the external electrode 7 is connected to the conductive layer 6.
The external electrode A is pressurized with a small force such that it makes contact with the external electrode A and is energized.

Next, after the five-resistance welding electrode tip 8 retreats, the laser beam 11 generated by the laser generator 9 is emitted.

It passes through the optical system 1o and scans the range where the external electrode 7 is temporarily welded to the conductive layer 6. At this time, if the condensed diameter of the laser beam 11 is larger than the welding range, scanning may not be performed.

Also, Figure 2 shows a part of the resistance welding electrode tip.

This is a diagram in which the conductive layer is in contact with the external electrode outside the contact range of the external electrode, and all the constituent elements are the same as in Fig. 1. This method allows the external electrode to be welded, and is more effective than the case shown in FIG.

As described above, according to this example, after temporarily welding the conductive layer and the external electrode using the resistance welding method, welding is performed using a laser beam, thereby reducing damage caused to the film capacitor element during welding and melting. It is possible to weld external electrodes without causing sparks.

Note that the laser beam in the present invention is a YAG laser.
, or a Co2 laser. The selection of the laser depends on the combination of metals to be welded; for example, if the conductive material is zinc,
If the external electrode material is copper-based metal, multimode YA
G, or Co2 lasers can be used.

In this case, the laser should be selected so that the energy density of the laser beam is less than or equal to the evaporation energy density of the metal to be welded.
This can be done from the viewpoint that the distribution state is 7 rats.

Effects of the Invention As described above, the present invention prevents damage to the film capacitor element during welding and the occurrence of welding cracks by pre-welding an external electrode to a conductive layer using a resistance welding method and then performing laser welding. All external electrodes can be welded,
Its practical effect is that of a dog.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing the main components of the manufacturing method in one embodiment of the present invention, and FIG. 2 is a diagram showing the main components of the manufacturing method in another embodiment of the present invention, in which a part of the resistance welding electrode tip is connected to the conductive layer and the external electrode. Fig. 3 is an enlarged cross-sectional view of a part of a conventional film capacitor showing its structure; Fig. 4 is a cross-sectional view of a conventional film capacitor. FIG. 3 is a perspective view showing a state when external electrodes are drawn out in FIG. 6... Conductive layer, 7... External electrode, 8...
. . . Resistance welding electrode tip, 9 . . . Laser generating section, 1o. Curved optical system, 11 . . . Laser beam.

Claims (1)

[Claims] When connecting an external electrode to the conductive layer of a film capacitor element having conductive layers formed on both end faces, after temporarily welding the conductive layer of the film capacitor element and the external electrode by a resistance welding method, using a laser beam, A method for manufacturing a film capacitor, comprising melting the conductive layer and the external electrode.