JPH02303108A - Manufacture of capacitor - Google Patents

Abstract

PURPOSE:To completely adhere an electrode foil to a lead plate for preventing poor contact of the electrode foil with the lead plate and improving current resistance by interposing a laminate protective insulating foil, in which thermomelting resin is laminated in a lead plate insertion part, to melt and solidify thermomelting resin. CONSTITUTION:When a capacitor element, in which an electrode foil 1 such as an aluminum foil and a dielectric 2 such as insulating paper and a plastic film are laminated, a lead plate 3 is inserted in contact with the electrode foil 1 and a laminate protective insulating foil 6 is interposed to the part where the lead plate 3 is inserted so that thermomelting resin 5 may oppose to the lead plate 3 for being wound about, is housed in a case while being heated at above a melting temperature of the thermomelting resin 5 of the laminate protective insulating foil 6 while at a prescribed temperature under a softening temperature of a plastic film dielectric 2, thermomelting resin 5 is melted. Then, being cooled after heating for a prescribed time, thermomelting resin is solidified, so that the lead plate 3 is completely adhered to the electrode foil 1 by thermomelting resin 5.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing a capacitor that prevents poor contact between electrode foil and lead plate and improves current resistance.

2. Description of the Related Art A conventional capacitor is constructed by laminating an electrode foil 1 such as aluminum foil and a dielectric material 2 such as insulating paper or plastic film, as shown in FIG. 4, and inserting a lead plate 3 in contact with the electrode foil 1. A protective insulating stone 4 such as insulating paper or plastic film is inserted into the part where the lead plate 3 is inserted, and the wound capacitor element is stored in a case, dried at a predetermined temperature, and then impregnated and filled with an impregnating agent. They were making capacitors.

Problems to be Solved by the Invention However, in the above capacitor, when the cylindrical capacitor element is softly wound, or when the flat capacitor element is weakly tightened, the contact between the electrode foil 1 and the lead plate 3 is surface contact. Otherwise, point contact may occur, resulting in poor contact. If a high voltage is applied to the capacitor in such a point contact state, a large current will flow to the point contact between the electrode foil 1 and the lead plate 3. Heat is generated, and the dielectric material in the vicinity gradually deteriorates, eventually leading to dielectric breakdown.

In order to prevent this problem, it is necessary to pay careful attention to the shape, dimensions, number of inserts, and tightening dimensions of the capacitor element of the lead plate 3 depending on the purpose of the capacitor, resulting in disadvantages such as a complicated manufacturing process. was there.

Means for Solving the Problems The present invention seeks to provide a method for manufacturing capacitors that eliminates the above-mentioned drawbacks. That is, the present invention laminates an electrode foil and a dielectric material made of insulating paper or/and a plastic film, and inserts a lead plate in contact with the electrode foil, and the melting temperature of the lead plate insertion portion is set to the softening temperature of the plastic film. A capacitor element wound with a laminated protective insulating foil laminated with the following hot-melt resin laminated thereon is heated at a predetermined temperature to melt and solidify the hot-melt resin, and the lead plate and electrode foil are brought into close contact with each other. This is a distinctive method for manufacturing capacitors.

Function: When the capacitor element is heated at a predetermined temperature that is above the melting temperature of the thermofusible resin of the laminate protective insulation foil and below the softening temperature of the plastic film dielectric, the thermofusible resin melts, and after heating for a predetermined time. When cooled, the thermofusible resin solidifies, and the lead plate completely adheres to the electrode stone.

EXAMPLE The present invention will be described below with reference to an example shown in FIGS. 1 to 3.

FIG. 2 is a cross-sectional view of the laminate protective insulating foil 6. The laminate protective insulating foil 6 is made of insulating paper or polypropylene film,
Protective insulation stone 4 made of plastic film such as polyethylene terephthalate film, polypropylene resin, etc.
It is made by laminating a heat-melting resin 5 such as polyethylene resin.

FIG. 3 is a perspective view of the lead plate 3 placed on the hot-melt resin of the laminated protective insulating foil 6.

FIG. 1 is a sectional view of the main parts of the capacitor of the present invention, in which an electrode foil 1 such as aluminum foil and a dielectric material 2 such as insulating paper or plastic film are laminated, and a lead plate 3 is placed in contact with the electrode foil 1.
At the same time, a capacitor element is housed in a case, and a laminated protective insulating foil 6 is inserted and wound around the part where the lead plate 3 is inserted so that the thermofusible resin 5 faces the lead plate 3, When heated at a predetermined temperature that is higher than the melting temperature of the thermofusible resin 5 of the laminated protective insulation foil 6 and lower than the softening temperature of the plastic film dielectric 2, the thermofusible resin 5 is melted.

When heated for a predetermined time and then cooled, the thermofusible resin 5 solidifies, so that the lead plate 3 and the electrode foil 1 are completely brought into close contact with each other by the thermofusible resin 5.

After that, aromatic synthetic insulating oil such as alkylbenzene,
Capacitors were manufactured by impregnating and filling them with liquid impregnants such as bolybdenum oil, silicone oil, and vegetable oil, as well as waxes such as petroleum wax and synthetic wax.

Specific examples are shown in Table 1.

Depending on the type of dielectric used, the capacitor is dried at a predetermined temperature and for a predetermined time to perform deaeration and dehydration, and then heated at the above-mentioned heating temperature for a time to melt the thermofusible resin. In capacitors whose dielectric is only insulating paper such as capacitor paper,
Any temperature at which the thermofusible resin melts may be used.

The heat-melting resin preferably has a low melting point, and has a melting point of 95 to 95.
Polyethylene resin with a temperature of about 120°C is suitable.

As the dielectric material, insulating paper such as capacitor paper, or plastic film such as polypropylene film, polyethylene terephthalate film, polycarbonate film, polyvinylidene fluoride film, polyphenylene sulfide film, polytetrafluoroethylene film, or polyimide film is used.

Insulating paper such as kraft paper or heat-resistant plastic film such as polyimide film is used as the protective insulating foil.

As the heat-melting resin, a plastic resin having a melting point of 95 to 170°C, such as polyethylene resin or polypropylene resin, is used.

Next, 10 capacitors of the present invention shown in Fig. 1 and 10 conventional capacitors shown in Fig. 4 were manufactured, and an inrush current of 20 kA was applied to each lead plate, and a DC withstand voltage test was conducted each time an inrush current was applied. An experiment was conducted to determine how many times the inrush current would cause the dielectric to break down. The results are shown in Table 2.

Table 2 Effects of the Invention As mentioned above, the capacitor of the present invention has a laminated protective insulating foil laminated with a heat-melt resin in the lead plate insertion portion, and the heat-melt resin is melted and solidified to form an electrode foil. It has the effect of completely adhering the lead plate, preventing poor contact between the electrode foil and the lead plate, and improving current resistance, and has great industrial and practical value.

[Brief explanation of drawings]

Fig. 1 is a sectional view of the main parts of the capacitor of the present invention, Fig. 2 is a sectional view of the laminated protective insulating foil according to the present invention, and Fig. 3 is the thermal meltability of the laminated protective insulating foil of Fig. 2. Put the lead board on! FIG. 4 is a sectional view of a main part of a conventional capacitor. 1: Electrode foil 2: Dielectric material 3: Lead plate 4: Protective insulating foil 5: Hot-melt resin 6: Laminated protective insulating foil

Claims (1)

[Claims] A dielectric material made of electrode foil and insulating paper or/and plastic film is laminated, a lead plate is inserted in contact with the electrode foil, and a heat-melting material whose melting temperature is lower than the softening temperature of the plastic film is inserted into the lead plate insertion portion. A capacitor characterized in that a capacitor element wound with a laminated protective insulating foil laminated with resin interposed therebetween is heated at a predetermined temperature to melt and solidify the thermofusible resin, thereby bringing the lead plate and electrode foil into close contact. manufacturing method.