JPH01257316A - Manufacture of high-voltage capacitor - Google Patents

Abstract

PURPOSE:To improve a corona discharge characteristic by a method wherein a capaci tor element is housed in a container and treated by a vacuum, sulfur hexafluoride gas (SF6 gas) is filled into the container in a vacuum state, the circumference of the container is then molded by using a synthetic resin, and two or more pieces of this container-housed capacitor elements are assembled and molded collectively by using the synthetic resin. CONSTITUTION:A capacitor element is housed in a container; it is treated by a vacuum; SF6 gas is filled into the container; after that, the circumference of the capacitor element is molded by using a synthetic resin 20. Since SF6 gas can be filled at high density around an edge face of a metal thin film on both end faces of a winding of the capacitor element, a corona discharge firing voltage can be increased around the edge face of the metal thin film on both end faces of the winding of the capacitor element. Since an electrode can be formed and an extraction wire can be connected in the air, these operations can be executed easily; the corona discharge firing voltage can be increased also in parts where dielectric strength is weak, i.e. in a void part between metallized films 5, 6 to be wound and in a part around the edge face of the metal thin film on both end faces of the capacitor element; accordingly, a molded capacitor whose breakdown strength is high can be obtained.

Description

Detailed Description of the Invention (a) Object of the Invention [Field of Industrial Application] The present 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 and a metallized film on which 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.
Improvements in dielectric strength properties are required.

By the way, the Utility Model 1983, which aimed to solve the above problem,
There is a high-voltage capacitor proposed in Japanese Patent No. 107131.

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. This high-voltage capacitor has a structure in which terminals from the electrodes are led out on the outer surface of this synthetic resin part, and the high-voltage capacitor is manufactured by the following manufacturing method.

First, metallized films are stacked and rolled up in the air, metal is thermally sprayed on both end faces of the rolled up element to form electrodes, and lead wires are connected to these electrodes to obtain a capacitor element.Next, A plurality of the obtained capacitor elements are assembled, placed in 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, while keeping the insulating gas inside the mold in a positive pressure state, a flame-retardant synthetic resin liquid is injected.
A manufacturing method is used in which this synthetic resin liquid is heated to a curing temperature, and after the curing reaction, the mold is removed to take out the high-voltage capacitor.

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 rolled up in the atmosphere while being stacked, so air is trapped between the rolled up metallized films, and air voids are created between the rolled up metallized films. There are problems that exist.

Even if each capacitor element with such air voids is vacuum-dried, air and moisture in the uneven portions on both ends of the winding of each capacitor element can be removed.
There is a problem in that air voids existing between the metallized films 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 dissipated and the buoyancy becomes even greater. Therefore, there is a problem in that it is difficult to expect that the insulating gas will remain in the uneven portions on both ends of the winding of each capacitor element.

Therefore, the present invention improves the corona discharge characteristics by retaining SF6 gas at a high density in the dielectric strength weak points around the edge surfaces of the metal thin film 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 is to provide a capacitor manufacturing method that can be improved.

(B) Structure of the Invention [Means for Solving the Problems] In order to solve the above problems, the present invention first involves wrapping a metallized film in which a metal thin film is formed on a plastic film in an SF6 gas atmosphere. The process of forming electrodes on both end faces of the wound element and connecting the lead wires in the air, the process of placing the capacitor element with the electrodes formed and the lead wires connected in a container and vacuum processing, and vacuum treatment. A container-housed capacitor element is created through a step of filling SF6 gas into a container, and a step of molding a synthetic resin around the container filled with SF6 gas, and then assembling a plurality of these container-housed capacitor elements. The manufacturing method is characterized by the following steps: a step of molding the aggregate around the aggregate with a synthetic resin of the same type as the synthetic resin or a synthetic resin of a different type.

Each step will be explained below using the drawings.

Figure 1 is a schematic drawing of a film winding device that winds up metallized films while stacking them in an SF gas atmosphere. Figure 2 is an enlarged sectional view of the main parts of a capacitor element.
The figure schematically shows a vacuum chamber apparatus capable of vacuum treatment, introduction of SF6 gas, and synthetic resin molding, and FIG. 4 is a cutaway sectional view of a high-pressure capacitor.

The film winding shaft of the film winding device is connected to tank 1.
It is set so that when SF6 gas is put into tank 1, it enters the pool of SF6 gas that accumulates at the bottom because it has a density about five times that of air 2.

When the metallized films 5 and 6 are rolled up in the atmosphere of the SF6 gas 3 accumulated at the bottom of the tank 1, the SF6 gas 3 is trapped in the gap created between the rolled up metallized films 5 and 6, and the film is rolled up. The metallized film of the device easily produces voids 7 of SF6 gas 3.

Further, as for winding the metallized film in an SF6 gas atmosphere, for example, although not shown in the drawings, the metallized film 5.6 may be wound while introducing SF6 gas immediately before winding.

In this case, SF6 gas 3 is trapped in the gap created between the metalized films 5 and 6 being wound up, as described above, and voids 7 of SF6 gas 3 are created between the metalized films of the wound element. .

In order to continue manufacturing such elements, S is added in tank 1.
Since F6 gas is already in the tank, the bobbin 4 is set on the winding shaft through the upper opening of the tank 1, and various operations such as setting the metallized films 5 and 6 on the bobbin 4 are performed to remove the metal film. This will proceed to the winding operation in 5.6. When the amount of SF and gas in the tank 1 is exhausted and becomes small, it is replenished from the upper opening of the tank 1 as appropriate.

The voids 7 of the SF6 gas 3 generated between the metallized films may be in a state where they cannot easily escape, or may be in a state where they can easily flow out, depending on the position and shape of the void 7. Most of it is in a state where it cannot easily go out, and a part is in a state where it can flow out.

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. Solder 9a and 9b to form capacitor element 10
get.

At this time, among the voids 7 of the element, those in a state that cannot easily go out remain in the interior, and those in a state that can easily flow out will cause the SF6 gas to flow out.

This capacitor element 10 is housed in a container 12 in the atmosphere. Note that this container 12 includes a container body 12a and a lid 12.
The air inside the container 12 can be evacuated to the mating surface of b, the container can be filled with SF and gas, and the mold resin cannot enter into the container 12 when molding around the container 12 with synthetic resin. A gap 12c of a certain size is formed.

A glass cloth 11 is wrapped around the container 12 containing the capacitor element 10. The glass cloth 11 is made of a material having a gap that does not affect the evacuation of the air inside the container and the filling of SF6 gas.

A capacitor element 10 is housed in a container 12, a glass cloth 11 is wrapped around the container 12, and the capacitor element 10 is set in a mold 14 and placed in a vacuum chamber 15. When the valve 17 of the vacuum chamber 15 is opened and the other valves are closed to create a vacuum, the air inside the container 12 is exhausted from the gap 12C through the gap between the glass cloth 11 and out of the vacuum chamber 15, allowing vacuum processing to be performed.

Thereafter, valve 17 is closed, valve 18 is opened to introduce SF6 gas into vacuum chamber 15, and SF6 gas 3 is filled into container 12.

When this container 12 is filled with SF and gas, the SF and gas can be filled into the spaces where the SF6 gas that was stagnant during the electrode spraying and connection of the lead wires has flowed out.

Open the valve 19 and put the synthetic resin liquid 20' into the mold 14, surround the container 12 filled with SF6 gas with the synthetic resin liquid 20', and then keep the vacuum chamber at positive pressure. Heat to cause curing reaction. When the resin hardens, the molding of the synthetic resin 2o is completed, and the container-housed capacitor element 13 can be obtained by taking it out.

Next, a plurality of these container-housed capacitor elements 13 are assembled, this assembly is set in a mold 21, and the surroundings of this assembly are integrated with a synthetic resin 22 of the same type or different type as the synthetic resin 2o. can be molded into a high voltage capacitor.

(C) Effects of the invention (1) By winding and collecting the metallized film in an SF6 gas atmosphere, SF6 gas is trapped between the rolled up metallized films, and voids of the trapped SF6 gas are created. Most of the 7 is retained inside in a state where it cannot easily go out, and the void of the SF6 gas that has flowed out can be filled with SF6 gas in the subsequent process.
By forming the voids between the wound metallized films into voids of SF6 gas, an encased capacitor element having a high corona discharge starting voltage can be obtained.

+21 The SF6 gas stagnant inside can easily go out.
By being able to fill with F6 gas, metal spraying of electrodes can be carried out on both end faces of the winding after being taken out into the atmosphere, and lead wires can be connected, making electrode formation and lead wire connection operations easier.

(3) A series of steps in which the capacitor element is placed in a container, the container is vacuum-treated, the container is filled with SF6 gas, and then the container is molded with synthetic resin.
SF around the edge of the metal thin film on both ends of the capacitor element winding.
6 gas can be filled with high density, the corona discharge starting voltage around the edge surfaces of the metal thin film on both end surfaces of the capacitor element winding 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 edge surfaces 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.

(a) Also, since it becomes possible to test the operation of the container-housed capacitor elements at the stage of assembling them into an assembly, it is possible to determine whether the capacitor elements are good or bad, thereby reducing the number of ineffective man-hours in subsequent processes.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing the outline of the film winding device;
The figure shows an enlarged sectional view of a main part of a capacitor element, FIG. 3 is an explanatory diagram showing an outline of a vacuum chamber device, and FIG. 4 is a cutaway sectional view of a high-voltage capacitor. 1...Top opening tank, 2...Air, 3...SF
6 gas, 4...bobbin, 5.6...respectively metallized film, 7...SF6 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...Gold Mold, 15... Vacuum chamber, 16.17
, 18.19...Respectively valve, 20'...Synthetic resin liquid, 20...Synthetic resin, 21...Mold, 22...
・Synthetic resin. Patent applicant Risho Kogyo Co., Ltd.

Claims (1)

[Claims] First, a process of winding up a metallized film, which is a plastic film with a metal thin film formed thereon, in an atmosphere of sulfur hexafluoride gas (hereinafter simply referred to as SF_6 gas), and then attaching electrodes to both end faces of the element in the air. process of forming electrodes and connecting the lead wires, accommodating the capacitor element with the electrodes formed and connecting the lead wires in a container and vacuum-processing it, filling the vacuumed container with SF_6 gas, and the container filled with SF_6 gas. A container-housed capacitor element is created through a step of molding the surroundings with a synthetic resin, and then a step of assembling a plurality of these container-housed capacitor elements, the surroundings of this assembly are molded with synthetic resin of the same type as the synthetic resin or A manufacturing method for high-voltage capacitors that involves a process of integrally molding different types of synthetic resins.