JPH0437566B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Object of the Invention [Field of Industrial Application] This invention relates to a method of manufacturing a high-voltage capacitor used for electric power.

[Prior art] So-called wound capacitors, in which a plastic film is used as a dielectric material and a metallized film on which a metal is deposited are stacked and wound, are used for electric power because they are non-polar and have low dielectric loss. used for. However, when used under high voltage, corona discharge tends to occur at both ends of the winding, and improvements in dielectric strength characteristics are required.

By the way, there is a high-voltage capacitor proposed in Japanese Utility Model Application Publication No. 59-107131, which aims to solve the above-mentioned problem.

This high-voltage capacitor consists of a capacitor element formed by integrally winding an electrode and a dielectric material, which is filled with an insulating gas.The outer periphery of this capacitor element is further surrounded by a flame-retardant synthetic resin. It has a structure in which terminals from the electrodes are led out on the outer surface of this synthetic resin part, and this type of capacitor is generally manufactured by the following manufacturing method.

First, metallized films are stacked and wound up in the air, metal is thermally sprayed on both end faces of the wound element to form electrodes, and lead wires are connected to these electrodes to obtain a capacitor element. A plurality of the obtained capacitor elements are assembled and put into a mold and subjected to vacuum drying treatment.The vacuum mold is filled with insulating gas, and the insulating gas is injected into the gap between both ends of the winding of each capacitor element. After that, a flame-retardant synthetic resin liquid is injected while maintaining the insulating gas inside the mold at a positive pressure state, the synthetic resin liquid is heated to a curing temperature, and after the curing reaction, the mold is removed and the high-voltage capacitor is taken out. It is used.

High-voltage capacitors manufactured using this method can be expected to have a small amount of insulating gas stagnation in the uneven parts on both ends of the windings of each capacitor element, and at the same time improve corona discharge characteristics compared to capacitor elements that are not filled with insulating gas. It has the advantage of improving dielectric strength.

[Problems to be Solved by the Invention] However, in the above-mentioned high-voltage capacitor, the metallized films are wound up in the atmosphere while being stacked, so air is trapped between the wound metallized films and air voids are formed inside. There are problems that continue to exist.

Even if each capacitor element with such air voids is vacuum-dried, it is possible to remove air and moisture from the irregularities on both winding end faces of each capacitor element, but the air and moisture present between the metallized films can be removed. There is a problem in that the air voids present cannot be removed by this vacuum drying process.

In addition, when embedding each capacitor element filled with insulating gas in a positive pressure state in a synthetic resin liquid, the winding of the capacitor element is The insulating gas that had accumulated in the uneven parts of both end faces gains buoyancy from the synthetic resin liquid, and some of it flows out as bubbles in the synthetic resin liquid, and the synthetic resin liquid is heated to the curing reaction temperature. During the initial stage of curing, the viscosity of the synthetic resin liquid decreases, and the remaining insulating gas is warmed and its buoyancy becomes even greater, so the remaining SF ₆ gas forms bubbles and escapes. go. Therefore, there is a problem in that it is difficult to expect much of the insulating gas to remain in the uneven portions on both ends of the winding of each capacitor element.

Therefore, the present invention has developed corona discharge characteristics by allowing SF ₆ gas to remain at a high density in the dielectric strength weak points around the edge surfaces of the metal thin films on both ends of the winding of the capacitor element and in the dielectric strength weak points due to voids between the metallized films. The purpose of this paper is to provide a capacitor manufacturing method that can improve the

(b) Structure of the invention [Means for solving the problems] In order to solve the above problems, this invention has the following features:
First, a process of winding a metallized film, which is a metal thin film formed on a plastic film, in an SF ₆ gas atmosphere, a process of forming electrodes on both end faces of the element in the air, and connecting lead wires to the electrode. A container-housed capacitor element is created through a step of forming a capacitor element and housing the capacitor element with lead wires connected in a container, and then a step of assembling a plurality of these container-housed capacitor elements, and a step of vacuum-treating this assembly. The manufacturing method is characterized by the steps of filling SF ₆ gas into each vacuum container, and integrally molding the assembly with synthetic resin.

Each step will be explained below using the drawings.
Figure 1 is a schematic diagram of a film winding device that winds up metallized films while stacking them in an SF ₆ gas atmosphere, Figure 2 is an enlarged sectional view of the main parts of a capacitor element, and Figure 3 is a molding device. FIG.

The film winding shaft of the film winding device is
It is located at the bottom of tank 1, and is set so that when SF ₆ gas is introduced into tank 1, it enters the pool of SF ₆ gas that accumulates at the bottom because its density is about five times that of air 2.

When the metallized films 5 and 6 are wound up in the atmosphere of the SF ₆ gas 3 accumulated at the bottom of the tank 1, the SF ₆ gas 3 is trapped in the gap created between the wound metallized films 5 and 6. A void 7 of SF ₆ gas 3 is created between the metallized films of the wound element.

In addition, as for winding the metallized film in an SF ₆ gas atmosphere, for example, although not shown, immediately before winding the metallized films 5 and 6 to be wound,
Winding may be performed while introducing SF ₆ gas. In this case, the SF ₆ gas 3 is trapped in the gap created between the metalized films 5 and 6 being wound up in the same way as described above, and voids 7 of the SF ₆ gas 3 are created between the metalized films of the wound element. become.

To continue manufacturing such elements, since SF ₆ gas is already in tank 1,
The bobbin 4 is set on the winding shaft through the upper opening of the bobbin 4, and various operations such as setting the metallized films 5 and 6 on the bobbin 4 are carried out, and the process proceeds to the winding operation of the metallized films 5 and 6. It turns out. When the amount of SF ₆ gas in the tank 1 is exhausted and becomes low, it is replenished from the upper opening of the tank 1 as appropriate.

The voids 7 of the SF ₆ gas 3 generated between the metallized films may be in a state where they cannot easily escape depending on the position or shape of the void 7, or in a state where they can easily flow out. The majority are in a state where they cannot easily escape, but some are in a state where they can escape.

The wound element is exposed to the atmosphere, and metal is thermally sprayed onto the end face of the element to form connection electrodes 8a and 8b on the wound metal thin films 5a and 6a, and lead wires are connected to the electrodes 8a and 8b. 9a and 9b are soldered to obtain a capacitor element 10.

At this time, among the voids 7 of the element, those that cannot easily go out will stay inside, and those that can easily go out will cause SF ₆ gas to leak out. .

This capacitor element 10 is placed in a container 1 in the atmosphere.
2 to obtain a container-housed capacitor element 13. In addition, this container 12 can evacuate the air inside the container 12 on the fitting surface of the container body 12a and the lid body 12b, and can fill the container with SF ₆ gas. A gap 12c is formed to a size that prevents mold resin from penetrating into the container 12.

A glass cloth 11 is wrapped around a container 12 containing a capacitor element 10. The glass cloth 11 used has a gap that does not affect the evacuation of air in the container and the filling of SF ₆ gas.

Wrap the glass cloth 11 around the container-housed capacitor element 13 and collect a plurality of them.
Create a collective.

This assembly is set in a mold 14. As shown in FIG. 3, this molding die 14 allows the inside of the mold to be evacuated, SF ₆ gas can be introduced into the vacuumed mold, and synthetic resin liquid for molding can be introduced into the mold. It is ready for injection.

To draw a vacuum, valve 17 is opened, other valves are closed, and the vacuum pump is operated. container 12
The air inside can be exhausted from the gap 12c to the outside of the molding die 14 through the gap between the glass cloth 11 and vacuum processing can be performed.

Thereafter, when the valve 17 is closed and the valve 18 is opened to introduce the SF ₆ gas 3 into the mold 14, each container 12 in a vacuum state is filled with the SF ₆ gas 3.

When this container 12 is filled with SF ₆ gas,
Spray SF ₆ into the void where the SF ₆ gas that remained during the electrode spraying and lead wire connection leaked out.
It can be filled with gas.

The synthetic resin liquid 15' is poured into the mold 14 by opening the valve 19 and surrounded around the aggregate, and then heated to cause a curing reaction. When the resin hardens, the molding of the synthetic resin 15 is completed, and the high voltage capacitor can be obtained by taking it out.

(c) Effects of the invention (1) By winding up a metallized film in an SF ₆ gas atmosphere, SF ₆ gas is trapped between the rolled up metallized films, and the SF ₆ gas is trapped. Most of the voids 7 in the winding can be retained in the interior in a state where they cannot easily go out, and the empty space in the void part of the _SF6 gas that has flowed out can be filled with _SF6 gas in the subsequent process. By forming voids between double metallized films into voids of SF ₆ gas, a container-housed capacitor element with a high corona discharge starting voltage can be obtained.

(2) The SF ₆ gas stagnant inside cannot _easily go out, and by filling the voids of the SF ₆ gas that has leaked out, it can be taken out into the atmosphere and removed from both ends of the winding. Electrodes can be metal sprayed on the surface and lead wires can be connected, making it easy to form electrodes and
The work of connecting lead wires becomes easier.

(3) A series of steps in which each container-housed capacitor element that makes up the assembly is vacuum-treated, each container is filled with SF ₆ gas, and then the assembly is molded with synthetic resin. As a result, the capacitor element is wound around the edge of the metal thin film on both end faces.
Since the SF ₆ gas can be filled with high density, the corona discharge starting voltage around the edge surfaces of the metal thin film on both ends of the winding of the capacitor element can be increased.

In this way, the formation of electrodes and the connection of lead wires can be performed in the atmosphere, which makes the work easier, and the insulation of both the voids between the rolled-up metallized films and the areas around the edges of the metal thin films on both ends of the capacitor element can be improved. Since the corona discharge starting voltage can be increased even in weak parts of proof strength, this manufacturing method can produce molded capacitors with high breakdown voltage.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the outline of a film winding device, FIG. 2 is an enlarged sectional view of a main part of a capacitor element, and FIG. 3 is a cutaway sectional view of a molding device. 1...Top opening tank, 2...Air, 3...
SF ₆ gas, 4... bobbin, 5, 6... each metallized film, 7... SF ₆ gas void, 8a,
8b...Each electrode, 9a, 9b...Each lead wire, 10...Capacitor element, 11...
Glass cloth, 12... Container, 13... Container housed capacitor element, 14... Mold, 1
5'...Synthetic resin liquid, 15...Synthetic resin, 16,
17, 18, 19... each valve.

Claims (1)

[Claims] 1 First, a metallized film with a metal thin film formed on a plastic film is heated with sulfur hexafluoride gas (hereinafter referred to as
The process of winding the wound element in an atmosphere (simply referred to as SF ₆ gas), the process of forming electrodes on both end faces of the element and connecting the lead wires to the wound element in the atmosphere, and the process of forming electrodes and connecting the lead wires to the capacitor element. A container-housed capacitor element is created through a step of housing the container-housed capacitor elements in a container, and then a step of assembling a plurality of these container-housed capacitor elements, a step of vacuum processing this assembly, and a step of placing SF ₆ in each container in a vacuum state. A manufacturing method for high-voltage capacitors that is characterized by the steps of filling with gas and integrally molding the periphery of the assembly with synthetic resin.