JPS587632Y2 - metallized film capacitor - Google Patents

Description

[Detailed description of the invention] This invention relates to a metallized film capacitor with a new structure, and conventionally it has been considered to use a semiconductor at the end of the electrode metal layer for the purpose of mitigating the electric field at the end. However, the effect against partial discharge, which is very important for AC capacitors, could not be expected.

Therefore, the present inventor focused on the effect on the partial discharge inception voltage, and found that even when a semiconductor is used at the end of the electrode, the effect of improving the partial discharge inception voltage of the capacitor can be obtained only in the configuration of the present invention.

FIG. 1 shows a cross-sectional view of a capacitor using a semiconductor layer 2 for the purpose of mitigating the electric field at the edge, which has been mainly considered in the past, and in the figure, 1 is a dielectric layer, 2 is a semiconductor layer, 3 is a 4 is an electrode metal layer, and 4 is an electrode lead-out portion.

However, although the configuration of the conventional example shown in FIG. This may be due to the fact that the semiconductor layer 2 has a negative effect on the electrical connection between the electrode metal layer 3 and the electrode metal layer 3, and for this reason, the dielectric loss tangent characteristic, which is important for the capacitor function, increases and the insulation resistance value decreases. A decline etc. will occur.

The improved conventional structure shown in FIG. 2 has improved this drawback of characteristic deterioration, in which the semiconductor layer 2 is formed only on the surface portion of the dielectric layer 1 where the ends of the electrode metal layer 3 are formed. In the case of the structure shown in FIG. 2, although the deterioration of the electrical characteristics is reduced, there is still no significant improvement in the partial discharge inception voltage.

The present invention has been proposed in view of the above points, and the configuration of the present invention is shown in FIG. 3.

That is, the electrode metal layer 3 is provided on the dielectric layer 1 , and the semiconductor layer 2 is placed at the end of the electrode metal layer 3 facing the electrode lead-out part 4 so as not to be in contact with the electrode lead-out part 4 . The end portions are wrapped around each other to form a capacitor, and metallized films having such a structure are laminated to form a capacitor.

However, in the present invention, by having the above-mentioned structure, it is possible to obtain a remarkable improvement in the partial discharge inception voltage, which could not be obtained with the conventional metallized film capacitor having a semiconductor layer, and furthermore, the electrical This has the effect of dramatically increasing the breakdown voltage.

Next, an embodiment of the present invention will be described.

A polyethylene terephthalate film with a thickness of 9 μm was used as the dielectric layer 1, the electrode metal layer 3 was formed by vacuum evaporation of aluminum, and the semiconductor layer 2 was made of germanium.

Further, the electrode lead-out portion 4 was formed by metal spraying of zinc.

Using the same materials as above, partial discharge inception voltages were measured for the conventional structure shown in FIG. 1, the improved conventional structure shown in FIG. 2, and the present invention shown in FIG. 3, and the results are shown in the table below.

For the semiconductor layer 2, tests were also conducted on silicon, cadmium, selenium, antimony, carbon, and various other compound semiconductors, but only the configuration of the present invention had a significant effect on improving the partial discharge inception voltage. It was seen.

FIG. 4 shows a structure in which a semiconductor layer is formed entirely on the metal surface of an electrode, which has been conventionally considered for cables and the like.

In the figure, 1 is a dielectric layer, 2 is a semiconductor layer, 3 is an electrode metal layer, and 4 is a dielectric layer.
is an electrode lead-out part.

Although such a configuration certainly has the effect of improving the partial discharge inception voltage, it has a major problem in that the dielectric loss tangent (janδ value), which is extremely important for capacitor function, becomes large, resulting in a capacitor with degraded performance. was there.

FIG. 5 shows a comparison of dielectric loss tangent values (jan δ values) of the capacitors with the configurations of FIGS. 3 and 4.

In the figure, a indicates the tan δ value of the capacitor according to the present invention configuration shown in FIG. 3, and 6 indicates the tan δ value of the capacitor according to the configuration shown in FIG.

A comparison will be made of capacitors obtained using a polyethylene terephthalate film as the dielectric layer 1, aluminum as the electrode metal layer 3, and germanium as the semiconductor layer 2.

Since the present invention is configured as described above, the partial discharge inception voltage is improved, the electrical withstand voltage is increased, partial discharge deterioration etc. are drastically reduced, and a long-life and highly reliable metallized film container is provided. This has been shown to have extremely effective industrial effects.

[Brief explanation of the drawing]

Fig. 1 is a schematic sectional view of a conventional example, Fig. 2 is a schematic sectional view of an improved conventional example, Fig. 3 is a schematic sectional view of the present invention-embodiment, and Fig. 4 is a schematic sectional view of another conventional example. 5 is a comparative explanatory diagram of the conventional example shown in FIG. 4 and the embodiment shown in FIG. 3, where 1 is a dielectric layer, 2 is a semiconductor layer, 3 is an electrode metal layer, and 4 is an electrode lead-out portion.

Claims (1)

[Scope of utility model registration request] In a metallized film capacitor having a dielectric layer in contact with one electrode lead-out part and not in contact with the other electrode lead-out part,
A semiconductor layer is formed only at the end of the electrode metal layer formed on the dielectric layer that is spaced apart and opposed to the other electrode lead-out part so as to be in contact with the dielectric layer and not in contact with both electrode lead-out parts. Features of metallized film capacitors.