JPH0256912A - Manufacture of film capacitor - Google Patents

Abstract

PURPOSE:To maintain creeping distances between electrodes and make a cut surface clean by a method wherein a laser beam is applied to the cut surface to burn the electrodes exposed on the end surface and the edges of the electrodes are made to retreat from the end surface. CONSTITUTION:A defocused laser beam with a relatively low energy density i s applied to the whole cut surface 24 of a zigzag type film capacitor 22 successively. As a film sheet 12 is thicker than electrodes 16a and 16b and has a higher transmittance of a laser beam, the laser beam is mostly absorbed by the electrodes 16a and 16b and only the electrodes 16a and 16b are burnt and the respective edges 28a and 28b of the electrodes 16a and 16b are made to retreat from the cut surface 24 of the film capacitor 22. With this constitution, the creeping distance between the adjoining electrodes 16a and 16b can be increased and, at the same time, adhering substances on the cut surface 24 such as electrode metal pieces can be removed and a clean end surface can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a film capacitor, and more particularly to a method for treating electrodes exposed on a cut surface of, for example, a laminated or zigzag film capacitor.

[Prior art]

In conventional methods of manufacturing multilayer film capacitors, a series of laminates are formed and then cut along the length of the laminate to separate them into individual units.

In order to prevent such electrical discharge at the cut surface and increase the withstand voltage, for example, there are methods of applying insulation coating to the electrodes exposed on the cut surface, and using a mixture of film sheets with different heat shrinkage rates. A method is known in which the creepage distance between the electrodes on the cut surface is increased by heat treatment.

[Problems to be Solved by the Invention] According to the conventional manufacturing method, when the base material (laminate) of the film capacitor is cut, electrode metal adheres to the cut surface, reducing the yield rate. and reliability may deteriorate.

Furthermore, in the latter method, it is necessary to prepare a plurality of types of film sheets, which increases costs and complicates the manufacturing process, resulting in a decrease in productivity.

Therefore, the main object of the present invention is to provide a method for manufacturing a film capacitor that can easily obtain a high quality film capacitor.

[Means to solve the problem]

This invention is a method of manufacturing a film capacitor by laminating film sheets on which electrodes are formed and then cutting the laminate, in which the cut surfaces are irradiated with laser light to cut the electrodes exposed on the end faces. This is a method of manufacturing a film capacitor in which the electrode is burnt out, thereby positioning the edge of the electrode inward from the end surface.

[Effect]

Preferably, a defocused laser beam is irradiated onto the cut surface of the laminate. At this time, since the electrode has a smaller thickness and a lower laser beam transmittance than the film sheet, that is, a higher laser beam absorption rate, only the electrode is burned out. As a result, the edge of the electrode is located inward from the end surface of the film capacitor. At the same time, deposits on the end faces of the film capacitor are also removed.

[Effects of the Invention] According to the present invention, the creepage distance between the electrodes can be secured by simply irradiating the cut surface with laser light, and the cut surface can be kept clean, making it easy to produce high-quality film capacitors. Obtainable.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS. 1A to 6.

First, a laminate 10 shown in FIG. 3 is prepared. To obtain such a laminate 10, in this embodiment, as shown in FIGS. 1A and 1B, a long film sheet 12 made of, for example, PET, PC, or PPS is prepared. Electrodes 16a and 16b made of, for example, aluminum, copper, or zinc are formed on both sides of the film sheet 12 in the longitudinal direction, leaving margins 14 at both ends of the film sheet 12 in the width direction. Then, as shown in FIG. 2, the film sheet 12, together with the electrodes 16a and 16b, is folded in the width direction while being continuous in the longitudinal direction.

Then, after applying an adhesive or the like to the surface of each of the meandering electrodes 16a and 16b, they are compressed and thermocompressed to form a prismatic laminate 10 as shown in FIG.
get. Next, each of the meander-folded electrodes 16
For example, the peaks 18a and 18b of a and 16b are made of aluminum.

Metallicon electrodes 20a and 20b made of zinc or tin are formed to serve as extraction electrodes.

Then, depending on the required capacity, the width direction (A-A' direction)
By cutting the film into square shapes, a zigzag-shaped film capacitor 22 as shown in FIG. 4 is obtained.

As shown in FIG. 5, a defocused beam with a relatively low energy density is directed toward the cut surface 24 of the serpentine film capacitor 22 formed by cutting the laminate 10 in this way, as shown in FIG. Sequentially irradiate the entire surface with laser light. Since the film sheet 12 is thicker than the electrodes 16a and 16b and has a higher laser beam transmittance, the laser beam is mainly absorbed by the electrodes 16a and 16b. Therefore, at this time, the absorption of laser light.

Only the electrodes 16a and 16b with a high rate are burnt out, and the sixth
As shown in the figure, the respective edges 28a and 28b of the electrodes 16a and 16b are located inward from the cut surface 24 of the film capacitor 22. Depending on the type of laser beam, energy density, or irradiation time, experiments have shown that the depth of the edges 28a and 28b from the cut surface 24 can be made almost uniform at 50 to 200 μm. Since the creepage distance between adjacent electrodes 16a and 16b can be increased, the withstand voltage can be improved even if a thin film sheet 12 is used. At the same time, it is also possible to remove deposits such as electrode metal on the cut surface 24 of the film capacitor 22, resulting in a clean end surface, and in this respect, it is expected that the withstand voltage and reliability will be improved.

Note that by selecting and using the type and energy density of the laser beam, the electrodes 16a and 16b are burnt out, the film sheets 12 are softened, and the film sheets 12 are fixed to each other.
The edges 26a and 26b of and 16b can also be sealed.

In addition, in the above-mentioned example, a method for manufacturing a zigzag-shaped film capacitor was explained. However, it goes without saying that the present invention is equally applicable to a conventionally known laminate type (one in which a laminate is made by laminating a large number of film sheets one by one).

[Brief explanation of the drawing]

FIGS. 1A to 6 are illustrative views showing one embodiment of the present invention in order. FIGS. 1A and 1B show a state in which electrodes are formed on a film sheet, and FIG. 2 shows a state in which it is folded. , Fig. 3 shows the state in which the metallicon electrode is formed after being compressed, Fig. 4 shows the state in which it is then cut, Fig. 5 shows the state in which the cut surface is irradiated with laser light, and Fig. 6 shows the state in which the electrode is then formed. Indicates a state in which it has been burnt out. In the figure, 10 is a laminate, 16a, 16b are electrodes, 2
2 is a zigzag folded film capacitor, 24 is a cut surface, 2
Reference numeral 6 indicates a laser beam, and 28a and 28b indicate the edges of the electrodes. Patent Applicant Murata Manufacturing Co., Ltd. Agent Patent Attorney Yama 1) Yoshihiro 1A Figure Figure 1 Figure 1B

Claims (1)

[Claims] A method of manufacturing a film capacitor by cutting a laminate formed by laminating film sheets on which electrodes are formed, the electrodes being exposed on the cut surface by irradiating the cut surface with laser light. A method for producing a film capacitor, the method comprising burning out the electrode so that the edge of the electrode is located inward from the end surface.