JPH09199371A - Metallized film capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a smaller-sized capacitor with a security function which is hard to increase a capacitance reduction in a high temperature life test, and which has stable excellent safety operations. SOLUTION: A metal vapor-deposited electrode 3 is formed on one face or both faces of a dielectric 2, a plurality of split electrodes 1 are formed in longitudinal and width directions of the electrode part, the split electrodes are partitioned at P margine 4, a margin fuse 5 having a fuse function is provided in a certain pant or a plurality of positions, and when these films are wound or stacked, the margin fuse 5 is overlapped on a P margin 6 of a counter electrode of a layer above or below that. Further, with the arrangement that the P margin part on one side is overlapped on that on the reverse side, or a vertical margin 9 is overlapped on the margin fuse and P margin 4 on the reverse face, it is possible to obtain performance which is hard to increase a capacitance reduction even in a higher temperature life test as compared with a conventional film capacitor with security function, and which has stable excellent safety operations.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metallized film capacitor.

[0002]

2. Description of the Related Art A conventional capacitor having a security function is
It has a built-in current fuse and temperature fuse, and it prevents smoke, ignition, and destruction of the capacitor by activating them when an abnormality occurs. In recent years, the number of film capacitors themselves having the function is increasing. As shown in FIG. 3, the main part of the structure is that the counter electrode is divided into several divided electrodes with a lateral margin, and when abnormal, the deposited metal at the contact portion of the defective divided electrode is scattered to electrically Insulated. As a result, it does not cause short circuit or smoke emission. In addition, as shown in FIG. 4, all electrodes of the metal vapor deposition electrode are divided into a plurality of independent capacitance forming portions, and each capacitance forming portion is divided into some limited vapor deposition portions (hereinafter referred to as margin fuses). ), There is a type that uses a T margin to establish electrical continuity with other electrodes. For this capacitor,
When the defective part of the counter electrode is destroyed, some limited vapor deposition parts are electrically cut off by the current flowing into this capacity forming part, and the broken parts are electrically separated, so that a short circuit, rupture, or ignition occurs. do not become. In order to realize higher safety, a type in which a plurality of independent capacitance forming parts and some limited vapor deposition parts (hereinafter referred to as cells) are formed in the counter electrode part as shown in FIG. Things are coming out. When a large number of cells are formed, a large number of margin fuses can be arranged, so that the fuse sensitivity is improved, and a burst, a fire, or a short circuit does not occur in response to a larger external electric stress.

[0003]

When an AC voltage is applied to the capacitor, corona discharge occurs at about 200 V or more, but the type shown in FIG. 5 has many electrode edges in the counter electrode. When an air layer is interposed between the layers, electric discharge occurs between the layers starting from the electrode edge. When the electrode is aluminum (Al), aluminum is oxidized by discharge and aluminum oxide (Al ₂ O ₃ )
become. Since aluminum oxide is an insulator, the number of electrodes decreases and the capacity decreases. This corona discharge is likely to occur from the edge of the counter electrode, and when the corona discharge is oxidized, the corona discharge moves to the adjacent side and the area of aluminum oxide is expanded. Since this phenomenon also occurs in the margin fuse portion, the margin fuse becomes aluminum oxide and conduction is lost. At that time, the conduction of the cell portion is lost and the capacitance is reduced at one time, so that the capacitance change becomes large. Further, there is a proportional relationship between the area of the margin fuse and the current value required to cut it. As the area of the margin fuse decreases, the current value required to cut it decreases. Therefore, if the area of the margin fuse decreases due to corona discharge,
A marginal fuse is blown even by a small amount of inrush current due to self-healing and the capacity is reduced, which causes a problem in use. Moreover, if the length of the margin fuse decreases,
Since the fuse portion has a high resistance, the loss becomes large. Then, when an AC voltage is applied to the capacitor, the amount of self-heating caused by the flowing current increases, which may lead to smoke and ignition. Before smoke and ignition, the safety mechanism works due to the destruction of the defective part and the capacity decreases. As a means for solving this problem, in order to improve the corona onset voltage, a method of impregnating a capacitor with silicon oil or wax and substituting voids between the film layers with an impregnating agent to make corona less likely to occur. As another method, there is a method of suppressing the voltage applied between the electrode layers to be equal to or lower than the corona starting voltage by making the structure of the capacitor an internal series structure. However, these increase costs in the manufacturing process and shape, and there is a possibility that oil leakage may occur in impregnation. Further, if a large number of cells are formed in the counter electrode, the margin also increases, and the shape becomes large. And the number of places where corona discharge has increased,
Corona onset voltage drops. Since the present invention has a structure in which no corona discharge occurs in the margin fuse part,
It is an object of the present invention to provide a smaller capacitor with a security function, which is less likely to increase in capacity reduction even in a high temperature life test and has stable and good security operation.

[0004]

According to the present invention, a metal deposition electrode is formed on one side or both sides of a dielectric film, and a plurality of divided electrodes are formed in the longitudinal direction and the width direction of the electrode portion. A margin fuse having a fuse function is provided at a part or a plurality of locations separated by a P margin, and when the margin fuse is wound or laminated with this film, the margin fuse overlaps with the P margin portion of the upper or lower counter electrode. . Also, the P margin on one side and the P on the back side
The metallized film capacitor is characterized by overlapping with a margin part. According to the present invention, it is possible to obtain a smaller capacitor with a security function, in which the capacity phenomenon is less likely to increase even in a high temperature life test and which has stable and good security operation.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In the invention described in claim 1 of the present invention, a metal vapor deposition electrode is formed on one surface of a dielectric film, and a plurality of divided electrodes are formed in the longitudinal direction and the width direction of the electrode part. The divided electrodes are separated by a P margin, and when the film is wound or laminated, the margin fuse overlaps the P margin portions of the upper and lower opposing electrodes, which is a metallized film capacitor. In the high temperature life test, there is no significant capacity decrease due to disappearance of the vapor deposition electrode due to corona discharge, and stable safety operation is provided.

According to a second aspect of the present invention, metal deposition electrodes are formed on both surfaces of the dielectric film, and a plurality of divided electrodes are formed in the longitudinal direction and the width direction of both surfaces, and the divided electrodes are P margins. It is divided, and its margin fuse overlaps with the P margin portion on the back side. Alternatively, when the film is wound or laminated, the margin fuse overlaps with the P margin portions of the upper and lower opposing electrodes, which is the metallized film capacitor, and the vapor deposition electrode disappears in the corona discharge in the high temperature life test. There is no significant decrease in capacity due to, and it has stable safety operation.

According to a third aspect of the present invention, when the film of the first or second aspect is wound or laminated, the P margin overlaps with the fuse margin portions of the upper and lower counter electrodes to form a capacitor. A metallized film capacitor characterized by being miniaturized and having a smaller size. According to a fourth aspect of the present invention, when the film of the first or second aspect is wound or laminated, the vertical margin at the end in the film width direction and the margin fuse and P margin on the back side overlap each other to form a capacitor. It is a metallized film capacitor that can be miniaturized and has a smaller shape and stable safety operation.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. (Embodiment 1) FIG. 1 shows the structure of a metallized film capacitor of the present invention. In FIG. 1, the divided electrode 1 is a counter electrode deposited by aluminum or zinc. The dielectric 2 is a dielectric such as polyethylene naphthalate. When a defect occurs in the divided electrode 1, the margin fuse 5 acts as a fuse that electrically isolates the defective portion because the vaporized metal is scattered by the current flowing through the margin fuse 5. It is made of aluminum or zinc. The P margin 4 is a non-electrode part,
It has a function of dividing the counter electrode portion into small divided electrodes, and is formed simultaneously during vapor deposition or after vapor deposition. The vertical margin 9 serves to ensure the insulation between the metallikon 10 and the divided electrode 1 and at the same time, in the case of upper and lower or double-sided deposition, does not apply a voltage to the margin fuse 5 on the back side. Let it form. In describing the P margin and the divided electrodes, a rectangular pattern is used.
Although the pattern in which two split electrodes are formed in the film width direction has been described, the present invention is not limited to these patterns, and the same effect can be obtained with three or more electrodes.

[0009]

Examples of the present invention will be described below. Example 1 Using a metallized polyethylene terephthalate (hereinafter referred to as PET) film having a thickness of 5.0 μm and having aluminum vapor deposited, a P margin width is 0.5 mm and a margin fuse length is 0.3 mm. The single-sided vapor-deposited film formed on the above was wound to obtain a film capacitor. A capacitor obtained by winding the film shown in FIG. 3 in which a counter electrode is divided into several divided electrodes by a lateral margin with a PET 5 μm aluminum single-sided vapor deposition film of Conventional Example 1,
A film capacitor obtained by winding the PET 5 μm aluminum single-sided vapor deposition film of Conventional Example 2 having the current path portion on the counter electrode and 70 ° C. DC2 in Example 1
A high temperature load test of applying 75 V was performed. As a result, when comparing Example 1 with Conventional Example 1 and Conventional Example 2 as shown in FIG. 6, Example 1 was significantly improved in the 70 ° C. high temperature load test.

(Example 2) A double-sided metallized PET film having a thickness of 5.0 μm and having a P margin width of 0.5 mm and a fuse length of 0.3 mm formed on the opposite electrodes was used. The vapor deposition film was wound to obtain a film capacitor. In Example 2, a high temperature load test of applying AC 275 V at 70 ° C. was performed. The test results are shown in FIG. Table 1 shows the device volume ratio of 10 μF in Example 2.
Table 2 shows the corona starting voltages of Example 2 and Conventional Example 2.

As a result, comparing Example 2 with Conventional Example 2 as shown in FIG. 6, Example 2 was greatly improved in the 70 ° C. high temperature load test and the corona starting voltage.

[0012]

[Table 1]

[0013]

[Table 2]

In the description of the embodiments, specific dimensions and patterns have been described, but the present invention is not limited to these dimensions or patterns.

[0015]

EFFECT OF THE INVENTION The metallized film capacitor of the present invention has a structure in which the margin fuse is overlapped with the P margin portions of the upper and lower counter electrodes or the P margin and the vertical margin on the back side, so that the capacity reduction due to corona discharge hardly occurs and is stable. It has an advantageous effect that it has a security operation and can be downsized and reduced in cost.

[Brief description of drawings]

FIG. 1 is a perspective view showing the configuration of a metallized film capacitor according to the present invention.

FIG. 2 is a front / back pattern diagram of the metallized film capacitor of the present invention.

FIG. 3 is a configuration diagram of a conventional wound film capacitor of Conventional Example 1.

FIG. 4 is a block diagram of a conventional wound film capacitor.

FIG. 5 is a configuration diagram of a conventional wound film capacitor of Conventional Example 2.

FIG. 6 is a capacitance change characteristic diagram of a 70 ° C. high temperature load test of Example 1, Example 2, Conventional Example 1, and Conventional Example 2 of the present invention.

[Explanation of symbols]

 1 Split Electrode 2 Dielectric 3 Metal Vapor Deposition Electrode 4 P Margin 5 Margin Fuse 6 Backside P Margin 7 Laminating Film 8 Backside P Margin 9 Vertical Margin 10 Metallicon 11 Split Electrode 12 Horizontal Margin 13 Vaporization Fuse 14 Mosaic Margin 15 Vaporization Fuse

Claims (4)

[Claims] 1. A metal vapor-deposited electrode is formed on one surface of a dielectric film, and a plurality of divided electrodes are formed in a longitudinal direction and a width direction of the electrode part. The divided electrodes are separated by a non-electrode margin, and the margin is formed. A metallized film capacitor, characterized in that a margin fuse having a fuse function is provided in the portion of the above, and the margin fuse is overlapped with the margin fuse portions of the upper and lower counter electrodes. 2. A metal vapor-deposited electrode is formed on both surfaces of a dielectric film, and a plurality of divided electrodes are formed on both surfaces in the longitudinal direction and the width direction, and the divided electrodes have a fuse function provided in a margin portion. A metallized film capacitor, characterized in that it is divided by a margin fuse, and the margin fuse overlaps with a margin fuse portion on the back side or the margin fuse overlaps with the margin fuse portions of upper and lower counter electrodes. 3. When wound or laminated by using a film, the P margin overlaps with the fuse margin portions of the counter electrodes one above and one below.
The metallized film capacitor described. 4. The metallized film according to claim 1, wherein when the film is wound or laminated, a vertical margin at an end in the film width direction and a margin fuse and a P margin on the back side thereof overlap each other. Capacitors.