JPH0449245B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to metallized film capacitors used in electronic equipment.

Conventional technology In recent years, as electronic devices have become lighter, thinner, shorter, and more sophisticated, there has been a growing demand for electronic components to be more compact and have higher performance. This has become an urgent task.

An example of a conventional metallized film capacitor will be described below with reference to FIG.

In FIG. 4, reference numeral 5 denotes a dielectric film, and electrodes 6 are formed on both sides of the dielectric film 5 by vacuum evaporation to form a metallized film. Reference numeral 7 denotes a lacquer film formed on both sides of the double-sided metallized film, leaving both ends in the width direction, and thereby constitutes one lacquered double-sided metalized film.

After laminating the metallized films, a metal layer as the electrode extension portion 8 is formed on the end face. On this occasion,
Since the electrodes are independent, the desired capacitance cannot be obtained unless even one of the electrodes is bonded to the metal layer. Therefore, in this type of metallized film capacitor, improving the bonding state between the electrode and the electrode extension portion 8 is the most important factor in stabilizing the electrical characteristics of the capacitor. The electrode extension portion 8 is usually formed by metal spraying (hereinafter referred to as metallicon). Metallicon is a method in which compressed air is injected into molten metal to form molten balls that are blown onto the end surface and deposited. At this time, it is known that an alloy layer is formed between the molten sphere that has reached the electrode and the electrode, but the higher the melting point of the sprayed metal is compared to the melting point of the electrode, the more the electrode is melted, so the bond is is generally good.

However, since the sprayed metal of conventional metallized film capacitors uses zinc, its melting point is low and only a small amount of electrode metal can be alloyed with it.

On the other hand, in order to realize the miniaturization of film capacitors, the film and lacquer film have a thickness of about 1 μm. As a result, the contact area between the electrode and the sprayed metal becomes very small, so that the electrical coupling between the electrode and the electrode extraction layer becomes more disadvantageous.

Figure 5 shows the thicknesses of the film and Lutzker film, respectively, in a conventional metallized film capacitor.
3.5μm-2.0μm, 1.5μm-1.2μm and 1.2μm-
Results of charge/discharge tests under the same conditions when three types of capacitors A, B, and C, which differ only in dielectric thickness of 0.9 μm, have a capacitance of 0.1 μF (the tan δ value is the same as the tan δ value before the test). The number of times it takes to reach 1.5 times the value) is shown.

As is clear from the above, in this conventional metallized film capacitor, reducing the thickness of the dielectric to reduce the size is not preferable in terms of characteristics because it significantly deteriorates the electrical coupling between the electrode and the electrode lead layer.

Furthermore, it is well known that when zinc is used in a high temperature and high humidity atmosphere, there is a problem in that the zinc itself corrodes and loses electrical connection with the electrode in a short period of time.

On the other hand, when a copper-aluminum alloy with a very high melting point, weather resistance, and chemical stability is used as a metal spraying material for the electrode, the film and lacquer film on the end surface shrink and shrink due to the heat of the molten sphere. There is a problem in that deformation occurs and the electrical connection between the electrode and the electrode extraction layer worsens.

Problems to be Solved by the Invention As described above, when miniaturizing metallized film capacitors, the problem of deterioration of the electrical connection between the electrodes and the electrode extraction layer arises due to the material of the electrode extraction layer.

The present invention aims to solve the above-mentioned conventional problems, and aims to reduce the size of metallized film capacitors while improving the electrical characteristics of metallized film capacitors coated with metallized silicon.

Means for Solving the Problems In order to achieve this object, the metallized film capacitor of the present invention has laminated double-sided metalized films with lacquering, and has a zinc component ratio of 5% to 60% by weight on the end surface of the laminate. % copper-zinc alloy is metal-sprayed to form the electrode lead-out part.

Effect This configuration allows the capacitor element, especially the film and lacquer film, to be protected from heat without being affected.
The electrical connection between the electrode and the electrode extraction part is strong and
It is stabilizing.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the structure of a metallized film capacitor according to an embodiment of the present invention, and the basic structure is the same as that of the conventional example shown in FIG. In Figure 1, 1 is polyethylene terephthalate film (hereinafter referred to as PET film).
It has a thickness of 1.2 μm. Al electrodes 2 are formed on both sides of this PET film 1 by vacuum evaporation. After that, a lacquer film 3 of polycarbonate (referred to as PC) is applied to both sides of this metallized film.
is formed to a thickness of 0.9 μm to constitute a single lacquered double-sided metallized film. After laminating this lacquering double-sided metallized film, an electrode lead-out portion 4 is formed of copper-zinc alloy as an electrode lead-out.

Figure 2 shows that a charge/discharge test was conducted on the capacitor of this example with the zinc component ratio changed from 5% by weight to 10% by weight, and the tan δ of this capacitor was changed from the initial value. It shows the number of times until it becomes 1.5 times (the number of times tanδ failure occurs).

As is clear from this result, the component ratio of zinc is 75
At weight % or higher, tan δ failures occur less frequently.

On the other hand, if the component ratio of zinc is less than 5% by weight, the melting point becomes high and the film deterioration at the end face is promoted, so that the charge/discharge characteristics are significantly deteriorated. However, when the zinc component ratio is between 5% and 60% by weight,
It can be seen that even when using an ultra-thin dielectric film of about 1 μm, very excellent charge-discharge characteristics are exhibited.

Figure 3 shows the capacitance reduction rate and tan δ value in a 1000 hour humidity load test at 60°C and 95% RH when the zinc component ratio was changed in the same manner as in Figure 2.

According to this, the higher the component ratio of zinc, the more likely it is to corrode, so the variation in tan δ value increases, and when the component ratio of zinc exceeds 60% by weight, electrical contact becomes insufficient and capacitance increases. However, when the component ratio of zinc is 60% by weight or less, extremely excellent weather resistance is exhibited.

From the above results, in order to make the electrical contact between the electrode and the electrode extension part of the multilayer film capacitor shown in this example stable and strong, and to obtain even better weather resistance, it is necessary to The ratio is 5% by weight
A copper-zinc alloy containing up to 60% by weight may be used.

In addition, the composition ratio of copper and zinc is 30% by weight, respectively.
70% by weight and 40%-60% by weight of copper-zinc alloys with 2 to 3% of tertiary elements such as Sn, Al, Ni, etc.
The same effect as described above can be obtained with a commercially available alloy containing 3% by weight.

Furthermore, in this example, the film and lacquer film were respectively a PET film and a PC lacquer film, but if the film and lacquer film were respectively polyphenylene sulfide (PPS) and polyphenylene oxide (PPO), In addition to the above, high heat resistance can be imparted.

Effects of the Invention As described above, the present invention provides a metal film capacitor in which lacquered double-sided metallized films are laminated and a metal sprayed portion is formed on the end face, in which the component ratio of bad lead in the metal sprayed portion is from 5% by weight to 5% by weight. 60% by weight
By using the copper-zinc alloy between the two, it greatly contributes to the miniaturization of film capacitors and the improvement of reliability.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing a metallized film capacitor according to an embodiment of the present invention, and Fig. 2 is a charge/discharge test of each capacitor in which the zinc component ratio of the metallicon metal is changed in the metallized film capacitor of the present invention. Figure 3 shows the capacitance reduction rate and tanδ value in a moisture resistance load test for each capacitor with a different zinc component ratio in the metallicon metal in the metallized film capacitor of the present invention. Characteristic diagram, Figure 4 is a cross-sectional view of a conventional metallized film capacitor, Figure 5
The figure shows a conventional metallized film capacitor.
FIG. 3 is a characteristic diagram showing the results of a charge/discharge test performed on three types of capacitors of the same capacitance with different film and lacquer film thicknesses. 1...PET film, 2...Al electrode, 3...
Lutzker membrane, 4...electrode extraction part.

Claims (1)

[Claims] 1 laminating double-sided metallized films,
And the component ratio of zinc is 5% by weight on the end face of the laminate.
A metallized film capacitor characterized in that an electrode lead portion is formed by metal spraying a copper-zinc alloy of 60% by weight.