JPS5911612A - Metallized film condenser - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to improvements in metallized film capacitors.

At present, metallized film capacitors, which are made by laminating and winding non-metalized films together with single-sided metalized films or double-sided metalized films, utilize the properties of plastic films to provide high performance along with the self-healing characteristics unique to metalized layers. Voltage-resistant capacitors have been put into practical use in a wide range of applications, such as those used in equipment and communication applications, but in order to create capacitors with higher voltage resistance and higher potential gradient design, it is necessary to reduce the microscopic portions that occur between the laminated layers. There were major problems such as a decrease in breakdown voltage due to discharge and a decrease in capacitor capacity at the end of its life.

Research has been carried out to minimize the minute partial discharges that occur between the layers, and the laminated winding has been conducted so that the overlapping metallized surfaces of double-sided metallized films are connected to the metal sprayed part at the ends in the same direction. A rotating capacitor has been proposed. However, although micro partial discharges between layers can be sufficiently suppressed in this configuration, the metallized electrode layer has a double structure, which deteriorates the self-healing performance characteristic of the metalized electrode layer, making it difficult to improve the capacitor withstand voltage. It had the disadvantage that it was not fully achieved. Furthermore, in the capacitor structure in which double-sided metallized films are laminated and wound, it is possible to make the opposing metallized electrode layer that forms the capacitor capacitance thinner, in other words, to increase the sheet resistance value of the metallized layer, in order to improve self-healing performance. It is conceivable that when aluminum metal is used as the metallized electrode layer, minute partial discharges are suppressed, self-healing performance is improved by making the aluminum metal layer thinner, and the initial capacitor capacity is improved. As the metal layer becomes thinner, it becomes more likely to locally change into aluminum oxide, which has the disadvantage that the capacitor capacity decreases significantly during its lifetime.

When zinc metal is used as the metallized electrode layer, minute partial discharges between the layers can be suppressed, and self-healing performance can be improved by thinning each zinc-metal layer in the opposing parts.
The thermal conductivity of the zinc metal layer is poor, and by making the metal layer thinner, it becomes even more difficult for the heat generated inside the capacitor to dissipate to the outer periphery through the electrode layer. It had the disadvantage that a significant improvement in breakdown voltage could not be obtained.

The present invention eliminates the above-mentioned problems and drawbacks, provides higher durability,
The present invention provides a highly reliable, high-quality capacitor that can be designed to a high potential with extremely little decrease in capacitance even at N% life expectancy.

Hereinafter, the structure of the capacitor of the present invention will be explained with reference to the drawings. FIG. 1 is a cross-sectional view of a capacitor of the present invention. Strip-shaped non-metalized surfaces 1.2 on opposite ends of front and back surfaces
A double-sided zinc metallized film 3 having a double-sided zinc metallized film 3 and a double-sided aluminum metallized film 6 having band-shaped non-metallized surfaces 4 and 6 at mutually opposite ends of the front and back sides are combined into a zinc metallized layer 7 and an aluminum metallized layer 8 that overlap each other. are connected to the metal sprayed part 9 at the ends in the same direction. 10 is the metal sprayed part on the opposite side,
11 is a zinc metallization layer and 12 is an aluminum metallization layer. A cross-sectional view of a capacitor of the present invention in which the self-healing performance is further improved by reducing the thickness of the zinc metal layer and aluminum metal layer of the counter electrode part that forms the capacitor capacitance, that is, by increasing the sheet resistance value of the metallized electrode layer. is shown in Figure 2. The metallized layer at the end of the electrode lead-out side is thick, that is, the sheet resistance value is small, and the connection with the metal sprayed part is the same as that shown in Fig. 1. 13 is a double-sided zinc metallized film, 14 16 is a double-sided aluminum metallized film, 16 is a zinc metallized layer, 16 is an aluminum metallized layer, and 17 is a metal sprayed part.

Next, the effects of the present invention will be explained with specific examples.

Example 6 A double-sided zinc metallized polyethylene terephthalate film with a thickness of 6 μm and a double-sided aluminum gold film with a thickness of 6 μm were laminated and wound as shown in FIG. A 4 μF capacitor was fabricated.

FIG. 3 shows the results of the capacitance reduction rate during lifetime energization. In the figure, A is the characteristic of the above-mentioned capacitor of the present invention;
These are the results for a F capacitor. Lifetime charging was performed by continuously charging 300V at 700C. The results show that the capacitor of the present invention exhibits less capacity reduction and has stable quality compared to a conventional capacitor formed by laminating and winding double-sided aluminum metalized films.

Figure 4 shows the capacitor applied voltage and breakdown time characteristics (V-
The experimental results are shown for (characteristics). In the figure, C indicates V- of the capacitor of the present invention and V- of the capacitor with characteristics.
is a characteristic. From this result, it is clear that compared to a capacitor formed by laminating and winding double-sided zinc metalized films, the withstand voltage of the capacitor of the present invention is significantly improved, and a high potential gradient design is possible.

As described above, the present invention is capable of stably reducing the capacitance decrease during the energized life, which has been a drawback in capacitors formed by laminating and winding double-sided metallized films, which have conventionally been considered as a countermeasure against interlayer minute partial discharges. At the same time, it is a capacitor with a higher voltage resistance, and it also enables a design with a higher potential gradient, so its industrial potential is extremely large.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views of each embodiment of the metallized film capacitor according to the present invention, and FIG. 3 is a characteristic diagram of the capacitance reduction rate with respect to the lifetime electrification time of the capacitors according to the present invention and those without the present invention.
FIG. 4 is a characteristic diagram of applied voltage versus breakdown time for capacitors according to the invention and those not provided. 1.2, 4.5... Band-shaped non-metalized surface, 3, 13
...Double-sided zinc metallized film, 6.14...
...Double-sided aluminum metallized film, 7,11.1
5...Zinc metallized layer, 8,12.16...
...Aluminum metallization layer, 9,10.17...
Metal spraying section. Name of agent: Patent attorney Masao Nakao and 1 other person No. 1
Figure /l /6 14 21.3 Figure is charged 'F18 (Ima) Figure 4 is destroyed P, IJ (now)

Claims (1)

[Claims] Double-sided zinc metallized films with strip-shaped non-metallized surfaces on opposite edges of the front and back sides, as well as double-sided aluminum metallized films with strip-shaped non-metalized surfaces on opposite edges of the front and back sides. A metallized film formed by stacking and laminating or winding each band-shaped non-metalized surface in the same direction so that the overlapping zinc metallized layer and aluminum metallized layer are connected to the metal sprayed part at the ends in the same direction. Condenser.