JPH04164307A - Metallized film capacitor - Google Patents

Abstract

PURPOSE:To notably restrain the decrease in capacity for enhancing the protective properties by a method wherein one of the opposing evaporated electrodes is composed of Zn evaporated films while the other one is composed of Al and Zn mixed evaporated film. CONSTITUTION:The title metallized film capacitor is composed of one evaporated electrode comprising Al and Zn mixed evaporated films 1, the other one comprising Zn evaporated films 2, multiple separating slots 3 of the Al and Zn mixed evaporated films 1 and fuses 4. In such a constitution, since the evaporated electrodes are respectively composed of Zn evaporated films 2 and the mixed evaporated films 1, even if any oxide is formed in respective electrode ends or non-electrode parts in the opposing electrodes due to the electric field concentration by the edge effect, the loss of the evaporated electrode i.e., the decrease in capacity can be restrained since ZnO is a semiconductor.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applicable to power capacitors and electrical equipment capacitors used for power-related phase advancement and for driving motors, lighting equipment, etc., as well as various power supply circuits and capacitors. This article relates to metallized film capacitors for electronic devices used in communication equipment.

Conventional technology Conventionally, in order to prevent disasters such as explosions, this type of metallized film capacitor has been equipped with a safety device in the case of oil-impregnated capacitors in a metal case, and a dry type In the case of capacitors, a safety mechanism is attached, and the general configuration of this safety mechanism is that one vapor deposition electrode is divided and intermittent vapor deposition blank areas are provided within the divided electrode. be.

Note that as the vapor deposition electrode, an Al vapor deposition film or a Zn vapor deposition film is generally often used.

Problems to be Solved by the Invention However, the above-mentioned conventional metallized film capacitor using vapor-deposited electrodes has the following problems when an alternating current voltage is applied.

First, when the vapor-deposited electrode is made of Al, the safety mechanism operates well, but there is a problem in that the capacity decreases significantly. This is due to the self-healing effect and the fact that Al20s, which is formed by electrochemical reaction, is an insulator. It is.

Next, when the vapor deposition electrode is Zn, the decrease in capacity is small, but
There is a problem that the safety mechanism has poor operability, and this
This is because ZnO, which is formed by the same reaction as in the case of , is a semiconductor.

The present invention solves the above problems and aims to provide a metallized film capacitor with excellent safety properties.

Means for Solving the Problems In order to achieve the above object, the present invention attempts to obtain a capacitor in which the decrease in capacitance is reduced and the operability of the safety mechanism is improved by using a mixed vapor deposition of Al and Zn. One of the vapor-deposited electrodes is a mixed vapor-deposited film of At and Zn,
The other layer is a Zn vapor deposited film, and a plurality of dividing grooves and fuses are provided in the mixed vapor deposited film of Al and Zn.

Effect Therefore, according to the present invention, when an AC voltage is applied by setting one of the opposing vapor deposition electrodes to a Zn vapor deposition film and the other to a mixed vapor deposition film of Al and Zn, the generated ZnO is a semiconductor; Electric field concentration is relaxed, suppressing the increase of oxide or the receding of the electrode at the end face portion of the electrode, and reducing the decrease in capacitance.

Furthermore, the safety mechanism operates reliably by providing a plurality of dividing grooves and fuses in the mixed vapor deposition film containing an Al acid component with good self-healing properties.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

1 and 2 are a sectional view and a perspective view showing the structure of a metallized film capacitor in an embodiment of the present invention. In the figure, 1 is a mixed vapor deposited film of Al and Zn;
The l content is 5 to 20 wt%. 2 is a Zn vapor deposited film. A plurality of dividing grooves 3 and fuses 4 are provided in the mixed vapor deposited film 1 of Al and Zn. Further, 5 and 6 are plastic films provided with a mixed vapor deposited film 1 and a Zn vapor deposited film 2, respectively, and 7 is a metal reflective layer for leading out electrodes.

As shown in the figure, since the opposing vapor deposition electrodes are a Zn vapor deposition film 2 and a mixed vapor deposition film 1, respectively, at the end of each electrode,
Or, even if oxides are formed due to electric field concentration due to the edge effect in the electrode missing part that occurs between opposing electrodes,
Since ZnO is a semiconductor, loss of the deposited electrode, that is, reduction in capacity can be suppressed.

Furthermore, since the components of one of the mixed vapor deposited films 1 are Al and Zn, if a short circuit occurs inside the capacitor, the insulation will be removed by the Al203 generated by the self-recovery action of the Al acid component of the mixed vapor deposited film 1 before breakdown occurs. At the same time, a current flows into the short-circuited portion, and the fuse 4 provided in the mixed vapor deposition film 1 is blown out, so that the safety mechanism operates reliably.

In addition, a metallized film capacitor may be formed using a double-sided vapor-deposited film in which mixed vapor-deposited film 8111 and Zn-evaporated film 2 are formed on one side and the other side of one film, respectively, and a non-evaporated non-metalized film. A similar effect can be obtained.

Next, FIG. 3 shows the results of testing the metallized film capacitors according to the present example and the conventional example in a continuous durability test according to J15-C-4908. As is clear from the figure, the capacitance reduction of the metallized film capacitor of this example is larger than that of the conventional metallized film capacitor with a Zn vapor deposited film, but significantly smaller than that of the metalized film capacitor with an Al vapor deposited film.

In addition, the table below shows the results of testing the metallized film capacitors of this example and the conventional example in terms of safety in accordance with the same <JIS standard, safety test for capacitors with safety mechanisms, and it is clear from the table. It can be seen that the metallized film capacitor of the present invention has high safety.

Note that the metallized film capacitors of this example and the conventional example used in the test were all manufactured under the same manufacturing conditions except for the configuration of the vapor-deposited metal.

In this way, according to the above embodiment, one of the vapor deposition electrodes is A[
Because one layer is a mixed vapor deposited film of Zn and the other is a Zn vapor deposited film, and multiple dividing grooves and fuses are provided across the mixed vapor deposited film, the reduction in capacity is extremely small and excellent safety is achieved. Ta.

Effects of the Invention As is clear from the above embodiments, the present invention forms a mixed vapor deposited film of Al and Zn and is provided with a fuse mechanism, which makes it possible to suppress the decrease in capacity to an extremely low level and to improve safety. This can be significantly improved.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the main parts of a metallized film capacitor according to an embodiment of the present invention, FIG. 2 is a perspective view of the same metallized film capacitor in the middle of winding, and FIG. FIG. 3 is a characteristic diagram showing the results of a continuous durability test of a film capacitor. 1... Mixed vapor deposition film of Al and Zn, 2...
・Zn vapor deposited film, 3... Division groove, 4...
Hughes.

Claims (1)

[Claims] In a metallized film capacitor in which one vapor-deposited electrode is divided into a plurality of pieces and a fuse is provided, one of the vapor-deposited electrodes is a mixed vapor-deposited film of Al and Zn, the other is a Zn-deposited film, and
A metallized film capacitor with multiple dividing grooves and fuses in a mixed vapor-deposited film of Zn and Zn.