JPS6038271Y2 - Capacitor with safety device - Google Patents

Description

[Detailed description of the invention] This invention is designed to prevent dielectric breakdown in a wound type capacitor using a plastic film as a dielectric material, and when the capacitor element expands, the conductor such as conductive foil is cut and the capacitor is This relates to a capacitor with a safety device that prevents destruction and ignition.

In general, when a plastic film capacitor experiences an abnormality such as dielectric breakdown, the breakdown occurs as follows: initially, the capacitor element overheats due to overcurrent due to a partial short circuit, and then the area of the overheating rapidly expands, resulting in a thermal runaway state. The internal pressure rises and the capacitor element expands, or the molten plastic film blows out from the electrode side end face of the capacitor element and expands in volume, which may eventually destroy the case and cause a fire due to the blowout of flammable gas.

In order to safely use plastic film capacitors with such properties, the present invention is a safety device that uses volumetric expansion to operate reliably and cut off the electric circuit extremely quickly, thereby preventing capacitor destruction and ignition. The present invention provides capacitors with attached capacitors.

An embodiment of the present invention will be described below with reference to the drawings.

In the figure, 1 is an L-shaped terminal lead, and one end of this terminal lead 1 is aligned with the outer surface of an insulating plate 2 with relatively little elasticity, such as an ebonite plate, which is in contact with the flat surface of the capacitor element 4. At the same time, a conductive foil 3 is interposed between the end of the terminal lead 1 and one electrode of the capacitor element 4 for connection.

Instead of the conductive foil 3, it is also possible to use another conductor that is easily cut by the expansion of the capacitor element.

In the same way, place an insulating plate on the other flat surface of the capacitor element, stack an L-shaped terminal lead on this insulating plate, and connect the terminal lead and the other electrodes of the element with conductive foil or the capacitor element. The connection is made through a conductor that is easily cut.

In this way, the desired capacitor case 5 is connected to both electrodes of the capacitor element via a conductor, and the tips of the terminal leads aligned with both shoulder planes of the element protrude outside.
A desired capacitor is constructed by filling the capacitor case with a sealing resin 6.

When dielectric breakdown occurs in a capacitor constructed in this way, the flat surface of the capacitor element expands and the molten plastic film 7 blows out from the electrode surface of the capacitor element, as shown in FIG.

Either one of these situations may occur, or both may occur at the same time or in succession, but in either case, the flat surface of the capacitor element curves due to the volume expansion of the capacitor element, but the insulating plate has little elasticity. It does not bend like the element.

As a result, the insulating plate is pushed outward by the expanded capacitor element surface, and the insulating plate is separated from the capacitor element surface as shown in FIG. The capacitor is cut off and the progress of destruction of the capacitor is stopped.

The present invention has the advantage that it has an extremely simple structure and has a responsive interrupting property, so it can reliably prevent capacitor destruction and ignition, and it is easy to manufacture and can be provided at low cost.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a capacitor element with a safety device of the present invention, Fig. 2 is a partially cutaway front view, Fig. 3 is a cross-sectional plan view of Fig. 2, and Fig. 4 shows a state in which the safety device is activated. FIG. 1...Terminal lead, 2...Insulating plate, 3
... Conductive foil (or conductor), 4 ... Capacitor element, 5 ... Capacitor case, 6.
... Sealing resin, 7... Dissolved film.

Claims (1)

[Scope of utility model registration request] In a wound-type capacitor that uses plastic film as a dielectric, a hard insulating plate and an L-shaped terminal lead are layered and abutted on the flat surface of the outer surface of the capacitor element, and the ends of the terminal lead and the electrode of the capacitor element are placed in contact with each other. A safety device characterized in that a conductor that is easily cut by the expansion of the capacitor element is connected between the drawer parts by passing through the corner of the capacitor element, and this is sealed together with resin in the case. capacitor.