JP4434450B2 - Explosion-proof film capacitor. - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an explosion-proof film capacitor for high power and large current filled with insulating oil and used for an induction heating device or a resonance circuit of a resonance inverter.
[0002]
[Prior art]
High current film capacitor elements include organic polymer films with low dielectric loss and excellent dielectric strength, such as polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polypropylene (PP), and polyethylene (PE). Metal foils such as aluminum are alternately stacked and wound, the organic polymer film on the outer peripheral part is heat-sealed, metallized electrodes are sprayed on both ends, a capacitor element is formed, put in an insulating case and impregnated with oil It was sealed.
[0003]
The structure of the capacitor will be described in terms of the manufacturing method. As shown in Japanese Patent Application No. 11-253797, an organic polymer film and a metal foil such as aluminum are alternately stacked as shown in FIG. A capacitor element in which metallized electrodes are formed by metal spraying at both ends of the winding is accommodated in a cylindrical case made of an insulating resin, and an electrode lid provided with a plurality of holes is fitted to both ends of the case. Connection and sealing between the metallicon electrode of the capacitor element and the electrode lid in the hole portion of the electrode lid, and then filling with insulating oil from the hole portion of the other electrode lid, and then connection and sealing between the metallicon electrode and the electrode lid Sealing was performed simultaneously to form an oil-impregnated film capacitor.
[0004]
Further, metallicon electrodes on the metal foils at both ends of the capacitor element are radially formed to facilitate oil impregnation, and each divided electrode is connected in a plurality of holes provided in the electrode lid, so that a residual inductance value is obtained. And the current capacity was increased. However, in the conventional structure, when the capacitor element is short-circuited, an accident that the case explodes instantaneously and the oil inside scatters and damages the surrounding circuits has occurred.
[0005]
[Problems to be solved by the invention]
When the capacitor element is short-circuited like the oil-impregnated capacitor in the conventional structure, the case will explode instantly and the oil inside will scatter, without causing an accident that damages the surrounding circuits. It is to realize an explosion-proof film capacitor in which conduction of the capacitor element is interrupted and a safe state is maintained.
[0006]
[Means for Solving the Problems]
In the first invention, a dielectric film and a metal foil are laminated and wound, and a capacitor element having a metallicon electrode formed on both ends is housed in an insulating case, the upper and lower electrode lids are connected to the metallicon electrode, filled with insulating oil and sealed. In an oil-impregnated film capacitor, an explosion-proof film characterized in that an upper metallicon electrode is connected to an easily deformable bellows, and an electrode lid having a pressure reducing hole is fitted and connected to the bellows with a space therebetween. It is a capacitor.
[0007]
As shown in the cross-sectional view of FIG. 1, the upper metallicon electrode 3 of the capacitor element 11 wound around the core 5 is connected to the easily deformable bellows 1 by the solder connection portion 2, and the bellows is shown in the completed drawing of FIG. 3. Is connected to an electrode lid 13 having a decompression hole 12 and a terminal electrode 14 for attaching an external terminal with a space 4 therebetween, so that when the capacitor element is short-circuited, oil is boiled due to heat generation and the pressure inside the case is reduced. The height is increased instantaneously, and the deformable bellows connected to the metallicon electrode above the capacitor element is pushed up to be deformed. At this time, the metallicon electrode connected to the bellows is peeled off from the wound end portion of the electrode foil of the capacitor element and is opened, so that the short-circuit current is interrupted. For this reason, it is necessary to leave a predetermined amount of space for the bellows to be pushed up between the electrode lid having the decompression hole.
[0008]
A second invention is the explosion-proof film capacitor according to the above-mentioned explosion-proof film capacitor, wherein the bellows is a dish-shaped soft metal plate having a thickness of 0.05 to 0.5 mm.
[0009]
In the thin bellows 1 made of the soft metal plate on the plate shown in FIG. 4, the thickness of the bellows having a minimum space between the upper electrode lid for peeling the metallicon electrode is 0.05 mm or less. Then, the strength is too weak to absorb the pressure increase inside the case only by the deformation of the bellows, and the metallicon electrode is difficult to peel off on the entire surface. In addition, when the thickness is 0.5 mm or more, the bellows is not easily deformed due to an increase in pressure inside the capacitor. In order to deform the metallicon electrode until it is peeled off, it is necessary to give the strength of the outer case, reducing the case weight and cost. Cannot be intended.
[0010]
According to a third aspect of the present invention, in the explosion-proof film capacitor, a reinforcing tape is wound around the outer periphery of the capacitor element, and a metal plate is abutted and connected to the entire surface of the bottom metallicon electrode of the capacitor element in which the tape is fixed with resin. An explosion-proof film capacitor having a plate connected to a bottom electrode lid.
[0011]
When the capacitor element is short-circuited, the bottom of the capacitor element is reinforced with the metal plate 9 in order to deform the bellows due to the pressure increase inside the capacitor, rather than having the resin case 7 strong as shown in FIG. By reinforcing the outer periphery by winding the reinforcing tape 10 and increasing the strength to withstand the internal pressure that deforms the upper bellows, the bellows deforms due to the increased pressure in the capacitor element, and the electrode is peeled off. An explosion-proof film capacitor using this case can be constructed. A polyaramid tape, a glass cloth tape, or the like is used as the outer peripheral reinforcing tape.
[0012]
According to a fourth aspect of the present invention, there is provided the explosion-proof film capacitor according to the above-mentioned explosion-proof film capacitor, wherein the upper metallicon electrode of the capacitor element is formed in a plurality of island shapes.
[0013]
In order to facilitate the peeling of the metallicon electrode from the capacitor element by short-circuiting the capacitor element and pushing up the bellows, the non-metallicon part 6 is provided as shown in the sectional view of FIG. Form and connect the upper bellows and bottom reinforcing metal plate 9 with the connection part 2 and fix the bottom part with a screw hole 8 so that the metallicon electrode can be easily peeled off from the capacitor element. A balance between the ease of deformation of the bellows and the ease of peeling of the metallicon electrode is kept so that the increased pressure acts on the deformation of the bellows and the peeling of the metallicon electrode. The island-shaped metallicon electrode shape is formed on a fan-shaped metallicon electrode that is radially separated from the center of the capacitor element so that the residual inductance does not increase and the oil impregnation property is improved.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The explosion-proof film capacitor of the present invention is a circuit in which the capacitor element in the case is short-circuited and the bellows connected to one metallicon electrode of the capacitor element is deformed by the increased pressure inside, and at the same time, the metallicon electrode is peeled off from the capacitor element and opened Put it in a state. In addition, by using a thin plate-shaped soft metal plate as the bellows, the thickness of the case can be reduced and the height of the case can be reduced.In addition, the outer periphery and bottom of the capacitor element are reinforced, and the increased pressure when the capacitor element is short-circuited The metallicon electrode is formed into a plurality of islands to facilitate peeling.
[0015]
[Example 1]
Hereinafter, embodiments of the present invention will be described in terms of manufacturing methods. Outer diameter: 20 mmΦ, length: 100 mm, material: Polyacetal core, thickness: 30 μm, width: 100 mm three-layer polypropylene (PP) film, thickness: 6 μm, width: 90 mm aluminum The foil was protruded 2 mm from the polypropylene (PP) film, and two layers were laminated alternately, and a film capacitor element having an outer diameter of 95 mmΦ was scraped off.
[0016]
Next, the capacitor element is wound 10 times with a glass cloth having a thickness of 20 μm and a width of 100 mm, impregnated with epoxy resin, cured and reinforced, and then subjected to cross-shaped masking for the oil-impregnated passage. Then, a tin alloy was metallized to form a capacitor element with a metallicon electrode having an outer diameter of 95 mmΦ and a length of 105 mm.
[0017]
Next, a capacitor element reinforced by abutting and connecting a 2 mm thick brass plate to the bottom electrode is placed in a cylindrical case made of epoxy resin having an inner diameter of 100 mmΦ, a length of 105 mm, and a thickness of 5 mm. 4 and from the top, cover the oil impregnated hole of 0.3mm dish-shaped annealed copper plate and the metallicon electrode of the capacitor element while aligning them, and bond the outer periphery to the case with epoxy resin After the oil impregnation from the hole of the plate-like annealed copper plate, the metallicon electrode and the plate-like annealed copper plate were connected and sealed from the hole.
[0018]
Next, in the hole part of the plate-shaped annealed copper plate, the connection and hermetic sealing are processed by soldering to the metallicon electrode of the capacitor element, and the upper electrode cover having a decompression hole is fitted and connected at the outer peripheral part. Thus, an explosion-proof film capacitor was constructed.
[0019]
【The invention's effect】
The explosion-proof film capacitor of the present invention, like the oil-impregnated capacitor element in the conventional structure, does not explode even if the capacitor element is short-circuited and the oil does not scatter, and the upper metallicon electrode of the capacitor element peels off inside the case It is released and is in a safe state. In addition, the strength of the outer periphery and bottom of the capacitor element is increased, the internal pressure acts on the upper bellows, and the deformable soft bellows is used and the metallicon electrode is formed in an island shape, so the capacitor element is short-circuited. Sometimes the metallicon electrode is instantaneously peeled off to be in a safe state, so that an ordinary explosion-proof film capacitor using an inexpensive capacitor case can be constructed.
[Brief description of the drawings]
FIG. 1 shows a plan view and a cross-sectional view of an explosion-proof film capacitor according to the present invention.
FIG. 2 shows a plan view and a cross-sectional view of a conventional oil-impregnated film capacitor.
FIG. 3 shows a plan view and a side view of the finished product.
FIG. 4 shows a plan view and a cross-sectional view of a bellows formed of a plate-like annealed copper plate.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Plate-shaped annealed copper plate bellows 2 ... Solder connection part 3 ... Metallicon electrode 4 ... Space 5 of bellows deformation ... Core 6 ...・ Non-metallic part 7... Resin case 8... Screw hole 9 .. Reinforced metal plate 10. ... Decompression hole 13 ... Electrode cover 14 ... Terminal electrode

Claims (4)

An oil-impregnated film formed by laminating and winding a dielectric film and a metal foil, housing a capacitor element with metallized electrodes on both ends in an insulating case, connecting the upper and lower electrode lids to the metallicon electrode, and filling and sealing with insulating oil An explosion-proof film capacitor, wherein an upper metallicon electrode is connected to an easily deformable bellows, and an upper electrode lid having a pressure reducing hole is fitted and connected to the bellows with a space therebetween. 2. The explosion-proof film capacitor according to claim 1, wherein the bellows is a dish-shaped soft metal plate having a thickness of 0.05 to 0.5 mm. 3. The explosion-proof film capacitor according to claim 1, wherein a tape is wound around the outer periphery of the capacitor element, a metal plate is contacted and connected to the entire surface of the bottom metallicon electrode, and the metal plate is connected to the bottom electrode lid. An explosion-proof film capacitor. The explosion-proof film capacitor according to any one of claims 1 to 3, wherein at least an upper metallicon electrode of the capacitor element is formed in a plurality of island shapes.

Images