JPS6044820B2 - Method of manufacturing metallized film capacitors - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a novel metallized film capacitor constructed by using a metallized film having a special structure as a dielectric material.

The dielectric film described above is an asymmetric film in which porous and dense layers coexist in a layered manner, and both layers are simultaneously developed on both the front and back surfaces of the dielectric at the time of film formation.

Conventionally, metallized film capacitors have used homogeneous and dense dielectric films.

However, although this capacitor has a self-healing effect based on minute discharges, under severe conditions such as using a high potential gradient, the self-healing effect increases as the amount of free carbon in the film increases, reducing the completeness of the action. .

The object of the invention is to overcome this drawback by developing a metallized film with a special structure by means of a special production method. That is, the metallized film capacitor manufactured by the manufacturing method of the present invention has features such as a low carbon content and a more complete self-healing action even under the above conditions. Metallization of the dielectric film by the manufacturing method of the present invention is as follows:
A homogeneous and dense layer on one side can be achieved using a vapor phase plating method such as vacuum evaporation, and a porous layer with continuous pores on the other side can be produced using electrolytic plating solution, electroless plating solution, conductive paint solution, metal plating solution, etc. This can be achieved by a liquid phase method such as impregnation with an ultrafine particle dispersion.

In addition, such dielectric films can be made of cellulose dielectrics such as acetyl cellulose, ethyl cellulose, butyl cellulose, and cyanoethylated cellulose, polycarbonate, polyethylene phthalate, polyethylene naphthalate, polybutylene terephthalate, various polyamides, polyimide, vinyl fluoride, and fluoride. Polymer materials such as vinylidene chloride, chlorinated vinyl fluoride, chlorinated vinylidene fluoride, and polystyrene can be used alone or in combination.

Furthermore, to form this structure, these polymeric materials are dissolved in a mixed solvent consisting of a high evaporation good solvent and a low or non-evaporation swelling agent, the prepared solution is cast onto a plate, and the high evaporation rate is maintained for a certain period of time. A dense layer is formed in the upper layer by evaporating a solvent rich in good properties, and when the board is put into a gelling solution with most of the swelling agent remaining, a gel layer appears in the lower layer, and the swelling agent The asymmetric structure is fixed by exuding it into the gel solution and washing it with water. After that, if vacuum drying or the like is performed, a dielectric film is obtained. In addition, in this method, the dielectric structure, that is, the thickness of the dense layer, the pores in the gel layer, etc., depends on the type and amount of solvent and swelling agent, the mixing of both, evaporation conditions, type of gelling liquid, liquid temperature, etc. You can control the state. Next, in order to form a capacitor element using the above dielectric film, electrodes are formed on both sides of the dielectric film by metallization, and then this is overlapped with another non-metalized dielectric film, or electrodes are formed on both sides of the dielectric film. Coating another dielectric on one or both sides of the dielectric film,
This is achieved by forming by a method such as glow discharge, and by winding and laminating these composite dielectrics.

The metallized film capacitor manufactured by the manufacturing method of the present invention thus achieved has various excellent characteristics, but
The biggest feature is that the self-healing action is extremely efficient,
There are no negative effects associated with this. That is, the deterioration of the electrical characteristics of the capacitor after voltage treatment is extremely small. This evaluates the amount of free carbon remaining in the dielectric during the self-healing action. In other words, as a result of various experimental studies, it was confirmed from the elemental analysis results of carbon in the dielectric film of each capacitor that the amount of free carbon in the capacitor of the present invention is extremely small compared to the case in a conventional homogeneous dense dielectric material. . This is based on the unique structure and shape of this dielectric film. That is, it was confirmed that this was due to the effects of the back surface shape of the homogeneous dense layer, the shape of the porous layer continuous thereto, and the electrode shape resulting from this. Also, due to this effect,
The dielectric of the present invention can be applied to polymers containing a small proportion of hydrogen and oxygen to carbon, since they have traditionally been considered unsuitable for metallized film capacitors in terms of self-healing action, and from the viewpoint of parachol-like chemical structures. Good results can be obtained when applied to body films. Furthermore, in the asymmetric dielectric film produced by the manufacturing method of the present invention, the dense layer serving as the effective dielectric is formed to be extremely thin, and this point also works effectively for self-healing.

Next, Tables 1 and 2 show examples of Kaizai according to the present invention.

Also, in Table 1 above, No. l, NO. The conditions for forming the asymmetric high-density film No. 4 were as shown in Table 2.
As is clear from the above explanation, the metallized film capacitor manufactured by the manufacturing method of the present invention has an extremely low carbon content ratio after voltage treatment, and has an effective self-healing effect. Therefore, the capacitor characteristics are good, and because the electrodes penetrate into the porous layer, it is possible to make the capacitor smaller and larger in capacity, and its industrial potential is extremely large.

Claims (1)

[Claims] 1 A polymeric material was dissolved in a highly evaporative solvent containing a low-evaporative swelling agent or a non-evaporative swelling agent, and cast to create an asymmetrical film in which a porous layer and a dense layer coexist in a layered manner. A method for manufacturing a metallized film capacitor, characterized in that the film is later metalized and configured as a dielectric.