JPH0437564B2 - - Google Patents

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 capacitor in which the weak point of dielectric strength is molded with synthetic resin with an insulating gas interposed therebetween.

[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, it is well known that when used under high voltage, corona discharge tends to occur at both ends of the winding.

By the way, there is an invention of a method for manufacturing a molded capacitor described in Japanese Patent Application Laid-open No. 72212/1983, which aims to improve the corona discharge starting voltage at both end faces of the winding.

The manufacturing method for this molded capacitor involves stacking and winding metallized films in the atmosphere.
Metal is thermally sprayed on both end faces of the wound element to form electrodes, lead wires are connected to these electrodes to obtain a capacitor element, and the obtained capacitor element is placed in a vacuum high temperature chamber for heat treatment and vacuum treatment. and
This is a manufacturing method in which a capacitor element is filled with insulating gas, and the capacitor element filled with insulating gas is buried in a molded resin and taken out.This method of manufacturing a molded capacitor has slight unevenness on both ends of the winding of the capacitor element. However, insulating gas can be expected to remain.
Compared to capacitor elements that are not filled with insulating gas, this has the advantage of improved corona discharge characteristics and improved dielectric strength.

[Problems to be Solved by the Invention] However, in the above method for manufacturing a molded capacitor, the metallized film is rolled up while being stacked in the atmosphere, so that the inner side of the wound metallized film and the metallized film facing it are There is a problem in that air is trapped between the metallized film surface and the metallized film surface facing outward, and the trapped air exists as air voids between the metallized films.

If such air is trapped and the capacitor element is heat-treated and vacuum-treated, it is possible to remove the air and moisture from the uneven parts on both ends of the winding of the capacitor element, but the air voids that exist between the metallized films are removed. However, there is a problem in that it cannot be removed by heat treatment or vacuum treatment.

In addition, when embedding a capacitor element filled with insulating gas in mold resin, the insulating gas that remained in the uneven parts of both ends of the winding of the capacitor element when the capacitor element was placed in the mold resin liquid. obtains buoyancy from the mold resin liquid and some of it leaves the mold resin liquid as bubbles, and when the mold resin liquid is raised to the curing reaction temperature to proceed with the curing reaction, the remaining insulating gas is removed. There is also the problem that the insulating gas cannot be expected to remain in the concave and convex portions of both ends of the winding of the capacitor element because it is warmed up, gains greater buoyancy, and exits the mold resin liquid as bubbles. .

Therefore, the present invention aims to improve the corona discharge characteristics of the weak points of dielectric strength around the edges of the metal thin film on both ends of the winding of a capacitor element wound with a metallized film, and the weak points of dielectric strength due to voids between the metallized films. The aim is to provide a method for manufacturing capacitors that can be measured.

(b) Structure of the invention [Means for solving the problems] In order to solve the above problems, this invention has the following features:
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 and connecting lead wires with the wound element in the air, and forming an electrode. The capacitor element with lead wires connected is housed in a container and subjected to vacuum treatment.
The manufacturing method is characterized by the steps of filling the container with SF ₆ gas and molding the container filled with SF ₆ gas with synthetic resin.

Each step will be explained below using the drawings.
Figure 1 is a schematic diagram of a film winding device that stacks and winds metallized films in an SF ₆ gas atmosphere, Figure 2 is a cross-sectional view of a molded capacitor, and Figure 3 is an enlarged view of the main parts of a molded capacitor. The cross-sectional view and FIG. 4 are drawings schematically showing a vacuum chamber apparatus capable of vacuum processing, SF ₆ gas introduction, and synthetic resin molding.

This is a schematic drawing of a device that stacks and winds metallized films in an SF ₆ gas atmosphere.
The winding section of the film winding machine, that is, the winding shaft and the introduction section of the metalized films 5 and 6 into the winding bobbin 4 are located at the bottom of the tank 1 which is open at the top.

Various operations such as setting the bobbin 4 and metallized films 5 and 6 onto the bobbin 4 are performed through the upper opening of the tank 1.

When SF ₆ gas 3 is put into tank 1, the density of SF ₆ gas 3 is about 5 times that of air 2, so tank 1
The air 2 inside gains buoyancy and rises, forming SF ₆ gas 3
accumulates from the bottom of tank 1, and near the bottom of tank 1
SF ₆ gas forms a dense pool of SF ₆ gas.
When the metallized films 5 and 6 are wound up in the atmosphere of SF ₆ gas 3 accumulated at the bottom of the tank 1, the gap created between the metalized filters 5 and 6 is
SF ₆ gas 3 is trapped and voids 7 of SF ₆ gas 3 are 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 an element, since SF ₆ gas is already contained in the tank 1, it is necessary to set the bobbin 4 through the upper opening of the tank 1, set the metallized films 5 and 6 onto the bobbin 4, etc. After performing various operations, the process proceeds to winding up the metal films 5 and 6, and when the amount of SF ₆ gas in the tank 1 becomes exhausted and decreases, the process can be continued by replenishing it as appropriate.

Occurred between the metalized films of the wound element.
Depending on the position and shape of the void 7, there are two types of voids 7 in SF ₆ gas 3: those that cannot easily escape and those that can easily escape. There are things that cannot go out, and some that can go 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. 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 remain in the interior, and those that can easily flow out will cause SF ₆ gas to flow out.

This capacitor element 10 is placed in a container 1 in the atmosphere.
2 to form 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 that is large enough to prevent the molding resin from entering the container 12 when the synthetic resin is molded around the container. Use one with enough clearance to not affect vacuuming and SF ₆ gas filling.

A glass cloth 11 is wrapped around this container-housed capacitor element 13 and set in a mold 14.
Place it in a vacuum chamber 15. When the valve 17 is opened and the other valves are closed to draw a vacuum inside the vacuum chamber 15, the glass cloth 11 wrapped around the container has a gap that does not affect the vacuuming of the air inside the container and the filling of SF ₆ gas. Container 12
Air inside the container 12 can also be exhausted to the outside of the vacuum chamber 15 from the gap 12c through the gap in the glass cloth 11.

Thereafter, the valve 17 is closed, the valve 18 is opened, SF ₆ gas is introduced into the vacuum chamber 15 , and the container 12 is filled with SF ₆ gas 3 . By filling this SF ₆ gas, the element is heated during electrode spraying and lead wire connection.
Among the SF ₆ gas voids 7, the spaces where SF ₆ gas has leaked out can also be filled.

Open the valve 19, put the synthetic resin liquid 20' into the mold 14, and pour the container 1 filled with SF ₆ gas.
2 is surrounded by a synthetic resin liquid 20', and then heated while maintaining a positive pressure in the vacuum chamber to cause a curing reaction. When the resin hardens, the molding of the synthetic resin 20 is completed, so that it can be taken out to obtain a molded capacitor.

(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. The corona discharge starting voltage can be increased by forming voids between the double metallized films into SF ₆ gas voids.

(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. Electric power metal spraying can be applied to the surface, and lead wires can be connected, making it possible to form electrodes,
The work of connecting lead wires becomes easier.

(3) The capacitor element is placed in a container, the container is vacuum-treated, the container is filled with SF ₆ gas, and the container is then molded with synthetic resin. Through a series of steps, both ends of the capacitor element are wound. Since SF ₆ gas can be densely filled around the edge of the metal thin film, the corona discharge starting voltage around the edge 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 the film winding device, Fig. 2 is a sectional view of the molded capacitor, and Fig. 3 is an explanatory diagram showing the outline of the film winding device.
The figure shows an enlarged sectional view of the main part of the molded capacitor, and FIG. 4 shows an explanatory diagram showing the outline of the vacuum chamber 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, 15... Vacuum chamber, 16, 17, 18, 19... Valve, 20'... Synthetic resin liquid, 20 ...Synthetic resin.

Claims (1)

[Claims] 1 The process of winding a metallized film, which is a metal thin film formed on a plastic film, in an atmosphere of sulfur hexafluoride gas (hereinafter referred to as SF ₆ gas), and applying electrodes to both end faces of the element in the air. The process of forming and connecting the lead wires, the process of housing the capacitor element with the electrodes formed and connecting the lead wires in a container and vacuum processing, the process of filling the vacuum container with SF ₆ gas, and filling the container with SF ₆ gas. A capacitor manufacturing method that involves a process of molding the container around it with synthetic resin.