JPH0722533U - Metallized film capacitors - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a metallized film capacitor having a reinforced element outer skin, which enables use in a high potential gradient. [Structure] At a winding end portion of metallized film capacitors 1 and 2, at least one electrode 3 of opposing metallized electrodes 3 and 4 is partially removed, and a protective film 5 is wound around the electrode-removed portion 6. After inserting and winding so that the start portions face each other, the protective film 5 is heat-sealed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a metallized film capacitor formed by winding a metallized film having a metallized electrode formed on the surface of a dielectric film.

[0002]

[Prior art]

 As shown in FIG. 9 and FIG. 10, the conventional metallized film capacitor has a structure in which a metal such as aluminum is vapor-deposited on the upper layer film 11 and the lower layer film 12, which are made of a dielectric material such as polypropylene, and are opposed to each other. By forming the divided electrodes 13 and 14, one of which is the divided electrode 13 and the other of which is the strip-shaped electrode 14, a safety function is provided, and the upper film 11 and the lower film 12 are stacked and wound. there were.

In the above structure, as a winding method, as shown in FIG. 9, the winding start portion of the protective film 15 is inserted so as to overlap the winding end portions of the films 11 and 12, and the protection is performed. A method of winding the film for use 15 and then heat-sealing it has been adopted.

As another winding method, as shown in FIG. 10, one electrode 14 is removed at the winding end portion of the lower layer film 12 to form an electrode removal surface 16, and the electrode removal surface 16 is formed. As a substitute for the protective film, the film may be wound and then heat-sealed.

[0005]

[Problems to be solved by the device]

 However, in the conventional example shown in FIG. 9 above, at the end of winding of the upper layer film 11, the dielectric is likely to be partially broken at the vapor deposition end of the divided electrode 13, and due to the presence of the protective film. Corona discharge is likely to occur due to the increase in the inter-layer gap, and the reduction of the capacitance that occurs during use is an obstacle to this, and there is the drawback that miniaturization due to the improvement of the potential gradient is hindered.

In another conventional example shown in FIG. 10, the strip-shaped electrode 14 is removed at the winding end portion of the lower layer film 12 on which the strip-shaped electrode 14 is formed, so that the upper layer film 11 and the lower layer film 12 are wound. Since the divided electrode 13 and the strip electrode 14 do not face each other at the end portion, partial breakdown of the dielectric body itself at the vapor deposition end of the divided electrode 13 at this portion does not occur, and this reduces the capacitance. Had the advantage that it would disappear. However, since the protective film is not used, it is difficult to strengthen the outer cover of the element, and when it is tightly wound, the lower layer film 12 and the upper layer film 11 are directly stressed, and this stress easily causes electrical breakdown. Therefore, this structure also has a drawback that it is difficult to reduce the size by improving the potential gradient.

The present invention has been made to solve the above-mentioned conventional drawbacks, and an object thereof is to provide a metallized film capacitor which enables use at a high potential gradient and has a reinforced outer cover of the device. Especially.

[0008]

[Means for Solving the Problems]

 Therefore, the metallized film capacitor of claim 1 is a metallized film capacitor in which a metallized film formed by forming a metallized electrode on a dielectric film is wound, and at least one electrode of the metallized electrodes facing each other is an insulating groove. At the end of winding of the metallized film, a part of at least one of the metallized electrodes facing each other is removed, and the electrode-removed part is protected. It is characterized in that the protective film is heat-sealed after being inserted and wound so that the winding start portions of the protective film face each other.

The metallized film capacitor according to a second aspect of the invention is characterized in that the electrode-removed portion is formed over a winding length of two or more turns from the winding end end.

Further, the metallized film capacitor according to claim 3 is characterized in that the opposing portion of the protective film and the electrode removed portion has a winding length of one rotation or more.

The metallized film capacitor according to claim 4 is characterized in that the outer winding portion of the protective film has a winding length of two or more turns.

[0012]

[Action]

 As a result of the above, in the metallized film capacitor according to claim 1, at least one electrode of the electrodes facing each other does not exist in the winding end portion of the metallized film, so that the dielectric substance at the winding end portion is The decrease in capacitance due to destruction or corona discharge is eliminated. In addition, since the protective film is used, the outer cover of the element can be strengthened, and the metallized film can be firmly wound without directly exerting stress. Since no direct stress is applied to the metallized film forming the capacitor in this way, electrical breakdown is suppressed.

Further, in the metallized film capacitor according to the second, third and fourth aspects, it is possible to more reliably reduce the dielectric breakdown and the capacitance reduction as described above, and to prevent the electrical breakdown. The element skin can be strengthened more reliably while pressing.

[0014]

【Example】

 Next, specific examples of the metallized film capacitor of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an exploded perspective view showing a main part of a metallized film capacitor according to an embodiment of the present invention. Referring to FIG. 1, a metallized film capacitor according to an embodiment of the present invention is formed by depositing a metal such as Al, Zn, or AlZn alloy on the surface of an upper film 1 of a two-layer dielectric film using a dielectric such as polypropylene or polyester. , The divided electrodes 3 divided in the length direction of the film are formed, and the strip-shaped electrodes 4 are also formed in the length direction of the film on the surface of the lower layer film 2, and the metallized films of these two layers are stacked. It has a structure in which the electrode lead-out portion is formed by spraying a metal material on both ends of the wire after winding.

In the above structure, the divided electrodes 3 formed on the upper layer film 1 are electrically separated from each other by insulating grooves, as shown in FIG. Further, the electrode-removed surface 6 or 7 is formed by removing either one of the divided electrodes 3 of the upper layer film 1 or the electrode 4 of the lower layer film 2 over a predetermined length, preferably two or more turns, from the winding end of the metallized film. To do. Then, as shown in FIG. 1, a winding start portion of a protective film 5 made of an insulating film is inserted onto the upper layer film 1 so as to face the electrode removing surface 6 or 7, and the protective film 5 is inserted. After winding 5 several times, the protective film 5 is heat-sealed. In this case, the length L ₁ of the portion where the protective film 5 and the electrode removing surface 6 or 7 face _{each other} is one rotation or more, and the length L ₂ of the outer wound portion of the protective film 5 is It is preferable to make the length necessary for winding two or more turns, preferably several turns. A protective film 5 may be inserted between the upper layer film 1 and the lower layer film 2. Alternatively, a band-shaped electrode may be formed on the upper layer film 1 and a divided electrode may be formed on the lower layer film 2.

By thus overlapping and winding the protective film 5 so as to face the burn-off region, corona discharge is less likely to occur, and a decrease in capacitance can be suppressed. In addition, since the protective winding is a separate film, it can be wound tightly, is resistant to external damage, and can be miniaturized by improving the potential gradient.

In the above-mentioned embodiment, as shown in FIG. 2, the divided electrodes 3 formed on the upper layer film 1 are electrodes having a shape electrically isolated from each other by an insulating groove. However, the present invention is not limited to this, and electrodes having various shapes as shown in FIGS. 3 to 7, and further, as shown in FIG. 8, the electrodes are divided into a large number of small electrodes in a mosaic shape by discontinuous insulating slits. It is also possible to use an electrode or the like in which the small electrodes are connected to each other by a fuse portion. Further, in the above embodiment, the divided electrodes 3 are formed only on the upper layer film 1, but the present invention is not limited to this, and the divided electrodes 3 are divided not only on the upper layer film 1 but also on the lower layer film 2. Electrodes can be formed. Furthermore, in the above-mentioned embodiment, the electrodes are formed on the surface of the two-layer film of the upper layer film 1 and the lower layer film 2, but the present invention is not limited to this, and the front and back surfaces of the single layer film are not limited thereto. It is also possible to form an electrode opposite to. Further, in the above-described embodiment, a part of one of the facing electrodes is removed at the winding end portion of the metallized film on which the electrodes are formed, but the present invention is not limited to this. Alternatively, the other electrode may be removed, or both electrodes may be removed.

[0019]

[Effect of device]

 As described above, the metallized film capacitor according to the first aspect can be used with a high potential gradient, and the outer cover of the element can be strengthened, whereby the performance of the metallized film capacitor can be improved.

Further, in the metallized film capacitor according to the second, third and fourth aspects, it is possible to more reliably use the metallized film capacitor with a high potential gradient, and it is possible to more surely strengthen the outer skin of the element.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a main part of an embodiment of a metallized film capacitor according to the present invention.

FIG. 2 is a developed plan view showing an electrode shape in the example.

FIG. 3 is a developed plan view showing a second embodiment of the electrode shape.

FIG. 4 is a developed plan view showing a third embodiment of electrode shapes.

FIG. 5 is a developed plan view showing a fourth embodiment of the electrode shape.

FIG. 6 is a developed plan view showing a fifth example of the electrode shape.

FIG. 7 is a developed plan view showing a sixth example of the electrode shape.

FIG. 8 is a developed plan view showing a seventh embodiment of the electrode shape.

FIG. 9 is a developed perspective view of a conventional example.

FIG. 10 is an exploded perspective view of another conventional example.

[Explanation of symbols]

 1 Upper Layer Film 2 Lower Layer Film 3 Divided Electrodes 4 Strip Electrodes 5 Protective Film 6 Electrode Removal Surface

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Creator Kaoru Mishima 10-45, Taisha-cho, Nishinomiya-shi, Hyogo Prefecture Shigetsu Electric Co., Ltd.

Claims (4)

[Scope of utility model registration request] 1. A metallized film capacitor comprising a metallized film formed by forming a metallized electrode on a dielectric film, wherein a plurality of metallized electrodes facing each other are separated by insulating grooves. At the end of winding of the metallized film having an electrode region,
After removing at least a part of at least one electrode of the metallized electrodes facing each other, after inserting and winding so that the winding start portion of the protective film faces the electrode-removed portion, the protective film A metallized film capacitor characterized by being heat-sealed. 2. The electrode removed portion is 2 from the end of winding.
The metallized film capacitor according to claim 1, wherein the metallized film capacitor is formed over a winding length of at least one rotation. 3. The metallized film capacitor according to claim 1, wherein the opposing portion of the protective film and the electrode-removed portion has a winding length of one rotation or more. 4. The outer winding portion of the protective film is 2
The metallized film capacitor according to claim 1, wherein the winding length is equal to or greater than a turn.