JPS5824932B2 - capacitor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a structure of a dry plastic film capacitor designed to ensure self-healing action.

related.

The dry plastic film capacitor is shown in Figure 1.
Gold is applied to one side of each of polypropylene or polyethylene terephthalate plastic films 1 and 2, which form the dielectric, in different directions.

Metal vapor-deposited films 3 and 4 are formed, these are overlapped and wound, metal electrodes 5.6 are formed on the ends of the winding by metal vapor deposition, and lead wires 7 and 8 are connected.

The simple equivalent circuit of such a capacitor is as shown in Figure 2, which is a unit capacitor C between the overlapped parts per turn.
are connected in parallel between metallicon electrodes 5 and 6 via metal vapor deposited films 3 and 4 for the number of turns.

If such a capacitor is used for a long time or under excessive heat or voltage conditions F, the films 1 and 2 will deteriorate, their withstand voltage will decrease, dielectric loss will increase, and the film 1 and 2 will deteriorate. , 2, the unit capacitor C corresponding to the deterioration point changes to a low resistance, and a large current flows.As a result, a large current flows in that part, causing excessive heat generation, and the vapor deposition in that part The metals 3 and 4 are scattered, and the unit capacitor C corresponding to the deteriorated portion is separated from the metallicon electrode 5.6, and the capacitance as a whole returns to a normal state from a state of high current conduction with a very slight decrease in capacitance.

In this way, even if an abnormality occurs due to film deterioration for some reason, dry type plastic film capacitors can return to a normal state by their own power, achieving extremely high reliability.
The present invention provides a capacitor structure that achieves higher reliability by devising the shape of the dielectric metal vapor deposition film to quickly and reliably perform such self-healing action.

3 and 4 show the structure of a dielectric film according to an embodiment of the present invention, in which a metallicon electrode 5 or 6 of a metal vapor deposited film 3 or 4 is formed on one side of the film 1 or 2 by thermal spraying. Non-metalized portions 9 are disposed intermittently on the metallized sprayed side, and metal gaps 10 are formed between the non-metalized portions 9.
It is characterized by the formation of

Such intermittent non-metalized portions 9 are easily formed by partially blinding during metal deposition.

A film 1 on which such metal vapor deposited films 3 and 4 are formed,
2 is wound in two layers in the same manner as in FIG. 1, and then metallicon electrodes 5 and 6 are formed on both end faces to complete the capacitor.

When such a capacitor is used, an abnormality of film dielectric breakdown occurs and a large current flows, but this large current is most concentrated in the metal gap 10 formed between the non-metallic IP parts 9 on the metallized sprayed side. The current density is high, and abnormal heat generation occurs earliest in this part, melting the films 1 and 2 near this metal gap 10, effectively cutting off the current flow to the film dielectric breakdown point, and causing the breakdown to spread further. prevent
Obtains normal operation and interrupts the process that leads to ignition and smoke.

If the destruction becomes even larger, abnormal heat generation in the metal slits 10 will be promoted, and the current will be cut off in the entire capacitor corresponding to each metal slit 10, the entire capacitor will be separated from the electrical circuit, and the ignition and smoke will be completely eliminated. is prevented.

Note that the metal slits on the metallicon sprayed side of each film may have any other structure as long as the current density is large and the amount of heat generated is large.

In the capacitor device according to the present invention, as described above, a portion with a high current density is formed on the metallicon sprayed side of a metal vapor-deposited film deposited on a plastic film, and this is polymerized and wound, and metallicon electrodes are provided on both end faces of the wound film. It is characterized by promoting self-recovery in the event of an abnormality, or effectively preventing ignition and smoke by cutting off the entire current, and providing an efficient protection function to the capacitor device itself with an extremely simple structure. done.

[Brief explanation of drawings]

Fig. 1 is a structural diagram of a conventional dry plastic film capacitor, Fig. 2 is a simplified equivalent circuit thereof, and Figs. 3 and 4 are a plan view and a perspective view showing the structure of a dielectric film used in the present invention. .

Claims (1)

[Claims] 1. A capacitor device characterized in that a portion with a high current density is formed on the metallicon sprayed side of a metal vapor-deposited film deposited on a plastic film, and this is polymerized and wound to provide metallicon electrodes on both ends of the wound surface.