JPS6226168B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing a capacitor in which an exterior is formed by thermally welding a composite film in which a thermoplastic plastic film is laminated to a metal foil. In general, the exterior of various types of capacitors such as aluminum electrolytic capacitors, tantalum electrolytic capacitors, plastic film capacitors, paper capacitors, and ceramic capacitors houses the capacitor element in a container made of metal such as aluminum or brass, or synthetic resin such as phenol, polypropylene, or polyethylene. Alternatively, the capacitor element may be coated with a synthetic resin such as epoxy or polyester. However, when the capacitor element is housed in a container made of metal or synthetic resin, a considerably large gap is created between the container and the capacitor element, resulting in a large-sized capacitor element, and the housing operation is complicated and requires many man-hours. In addition, when coating with synthetic resin, it is difficult to adjust the thickness of the coating layer, resulting in uneven thickness, resulting in non-uniformity, and the surface of the coating layer is uneven, deteriorating the appearance. Furthermore, as in Japanese Patent Publication No. 46-35653, there is a proposal to heat and pressurize and seal the recessed parts of a thermosetting resin sheet with a metal mold, but since a thermosetting resin sheet is used, heating is not necessary. The pressure must be maintained for a certain period of time, which adds unnecessary thermal stress to the capacitor element, causing characteristic deterioration. Furthermore, there has recently been a proposal to package a capacitor element by thermally welding a composite film made by laminating a plastic film to a metal foil, as in Japanese Patent Application Laid-Open No. 56-54032. When the foil is exposed and mounted on a printed circuit board, the exposed portion of the metal foil tends to come into contact with other peripheral components or with other peripheral components via the exposed portion of the metal foil, and furthermore, the terminal lead-out portion prevents short-circuiting of conductor circuits on the printed circuit board. There were drawbacks, such as the possibility that it would cause In order to eliminate the above-mentioned drawbacks, the present invention provides a method for manufacturing a capacitor that improves safety by preventing metal foil from being exposed in the cut cross section of a composite film that envelops a capacitor element and eliminating contact and short circuits between peripheral components. This is what I am trying to do. Embodiments of the present invention will be described below with reference to the drawings. That is, as shown in FIG.
A composite film 5 in which a thermoplastic plastic film 4 is laminated on both sides of a metal foil 3 as shown in the figure is placed around the plurality of capacitor elements 2, and each capacitor element 2 is heated simultaneously or one by one continuously. Welding is performed to form a heat-welded part 6, and the capacitor element 2 is wrapped and sealed with the composite film 5 to form an exterior. The composite film 5 includes metal foil 3 made of aluminum, tin, lead, or an alloy thereof, and polyethylene terephthalate, polyethylene terephthalate, etc.
Polycarbonate, polypropylene, polyamide, polyethylene, polysulfone, polyvinyl fluoride, ionomer, polyvinylidene fluoride, polyacetal, polyethylene fluoride, polyethylene naphthalate, polybutylene terephthalate, polyvinyl chloride, polyvinylidene chloride, polyphenylene oxide, etc. One or more types of thermoplastic plastic films 4 are laminated together. Thermal welding is performed using a heat sealer such as a hot plate or indenter on the top and bottom of the composite film 5, but instead of using a hot plate or indenter, an ultrasonic welder, friction welder, high frequency welder, impulse welder, etc. can be used as the heat sealer. may be used. Then, a welded portion 6 is formed by thermal welding and cut from the middle of the welded portion 6 between the plurality of sealed capacitor elements 2 to obtain individual capacitors 7 as shown in FIGS. 3 and 4. Next, a part or all of the welded portion 6 of the capacitor 7 is reheat-sealed using a heat sealer, and the composite film 5 is formed as shown in FIGS. 5 to 7.
A part of the thermoplastic plastic film 4 mainly on the inner surface is extruded to the outside from the edge of the welded part 6 to form an extruded part 8 that covers the exposed part of the metal foil 3 in the cut section. The width of the extrusion part 8 is determined from the experimental results described later.
If the width is 0.2 mm or more, the insulation is sufficient, and increasing this width only increases the external dimensions. Reheat welding is performed at a temperature of 100 to 400℃ and a pressure of 10 to 50℃.
Kg/cm ² and for a time of 0.1 to 5 seconds by selecting appropriate conditions depending on the material and thickness of the thermoplastic film 4, the width of the welded part 6, etc.; Requires a temperature higher than the softening point of No. 4. In addition, in consideration of a short circuit between both terminals 1, the metal foil 3 on the drawer side of the terminal 1 is
is made of thermoplastic film 4 in advance.
If it is located on the inner side, as shown in FIG. 4, the extruded portion 8 can be formed during thermal welding to form the welded portion 6. Therefore, in this case, only the part excluding the terminal drawer side is reheat-welded to form the extruded part 8.
All you have to do is form. The above-mentioned reheat welding is not only carried out after heat welding and cutting the capacitors individually, but also heat welding is first performed on only one side, cutting and heat welding the other side at the same time, and then reheat welding the cut welded parts. The extrusion portions may be sequentially formed by repeating this process. In addition, when perforations or notches are made, in order to avoid exposing the metal foil 3 from the outer peripheral surface after cutting, as shown in FIGS. At the same time, a notch 9 may be provided at the tip of the cut portion 10, the cut portion 10 may be reheated and welded to form the extruded portion 8, and the cut 9 may be separated. According to this FIG. 10, the notch 9 has a metal foil 3
Even if it is exposed, there is a recessed part from the outer circumferential surface, so even if it comes into contact with other peripheral parts, it will not cause a short circuit. The capacitor of the present invention, which is reheat-welded as described above, has no contact or short circuit between the metal foil and peripheral components in the cut cross section, and also has improved moisture resistance and weather resistance. It has the advantages of no need for coating, excellent workability, and great electrical insulation effect. Next, an example of comparison of characteristics between an embodiment of the present invention and a conventional reference example will be shown. The cut section of the capacitor 7 is shown in FIG.
1 and applied 100 VDC to check for conduction between the electrodes due to the metal foil on the cut surface. Table 1 shows the initial number of short circuits and the number of short circuits after being left at a temperature of 85°C for 1000 hours. The example has the configuration shown in FIG. 6 (width of the extruded part 0.2 mm), the example has the configuration shown in FIG. 9 (width of the extruded part 0.2 mm), and the reference example has the configuration as cut (no extruded part). Each sample is 100 pieces.

[Table] As is clear from Table 1, in the example, there were no short circuits, and the effect of reheat welding was remarkable, whereas in the reference example, all of which were cut, were conductive and short circuited. I understand. As detailed above, a composite film in which thermoplastic plastic film is laminated on both sides of metal foil is placed above and below a plurality of capacitor elements to which terminals are attached, and the periphery of the capacitor elements is thermally welded to seal the welded portion. After forming and sealing the capacitor element with the composite film, it was cut from the middle of the welded part to form individual capacitors, and then part or all of the welded part of the capacitor was reheat-welded to form an extruded part. This eliminates contact and short circuits between the metal foil and surrounding parts at the cut cross section, improves moisture resistance and weather resistance, eliminates the need to apply insulating paint, improves workability, and makes the product compact, lightweight, and sealable. , it is possible to provide a method for manufacturing a capacitor that is easy to mass-produce and is inexpensive.

[Brief explanation of the drawing]

The drawings are all explanatory diagrams of the present invention. Figure 1 is a plan view showing an example of heat welding of multiple capacitor elements with a composite film, Figure 2 is a sectional view showing an example of the composite film, and Figure 3 is a heat welding of multiple capacitor elements. A front view showing the cut capacitor after welding, Fig. 4 is its plan view, Fig. 5
The figure is a front view showing a reheat welded capacitor, No. 6
The figure is a plan view, FIG. 7 is an enlarged sectional view of part A in FIG. 5, and FIGS. 8 to 10 are related to other embodiments, and FIG. FIG. 9 is a plan view showing the state in which the extruded portion is formed, FIG. 10 is a plan view showing the capacitor in a cut state, and FIG. 11 is a plan view showing an example of the interelectrode continuity test. be. 1... Terminal, 2... Capacitor element, 3... Metal foil, 4... Thermoplastic plastic film, 5
... Composite film, 6 ... Welding part, 7 ... Capacitor, 8 ... Extrusion part, 9 ... Notch, 10 ... Cutting part, 11 ... Electrode plate.

Claims (1)

[Scope of Claims] 1. Means for attaching terminals to a plurality of capacitor elements, means for arranging a composite film in which thermoplastic plastic film is laminated on both sides of metal foil above and below the capacitor elements, and the composite film means for thermally welding the welded portions to form a welded portion; means for cutting the welded portion from the middle of the welded portion between the capacitor elements;
1. A method for manufacturing a capacitor, comprising: means for forming an extruded portion of 0.2 mm or more. 2. A means for attaching terminals to a plurality of capacitor elements, a means for arranging a composite film in which thermoplastic plastic film is laminated on both sides of metal foil above and below the capacitor elements, and a means for welding the composite film by thermal welding. a means for forming a section, a means for providing a cut section from both ends in the middle of the weld section, a means for providing a notch at the tip of the cut section, and reheat welding a part or all of the weld section to form an extruded section. A method for manufacturing a capacitor, comprising: means for cutting the capacitor, and means for cutting from the cutting portion.