JP3454043B2 - Metallized film capacitors - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power capacitor for improving power factor, a capacitor for electric equipment, a capacitor for various power supply circuits, a metallized film capacitor used for communication equipment and the like.

[0002]

Conventionally, known in such capacitors JP 4-225508 and JP-A-8-31690 discloses that used as fine dividing those and the film to add a fuse mechanism deposited metal of the metallized film Therefore, it is possible to manufacture a metallized film capacitor with a fuse mechanism using these known techniques.

[0003]

However, when a metallized film capacitor having such a conventional structure is used, there are various problems. That is, as shown in FIG. 6, the vapor deposition electrode is divided into a plurality of minute blocks 80 in the longitudinal direction and the width direction of the metallized film, and the plurality of minute electrodes are provided. If a minute breakdown that cannot be cleared by recovery occurs, an excessive short-circuit current flows and the fuse portion 60 operates to separate that portion from the metallized film capacitor, but the area of that portion is minute, so an adjacent minute block There is a problem that the current flowing from between 80 also activates the fuse portion 60 between the adjacent minute blocks 80, and the capacity is reduced even in a portion having no problem.

Further, when the fuse portion 60 does not operate due to a short-circuit current due to clearing of minute breakdown, breakdown in the block continues to progress, causing dielectric breakdown, and when it continues to progress, blocks around it continue to progress. The destruction spreads,
In the worst case, the metallized film capacitor may emit smoke or ignite.

Further, as shown in FIG. 7, in the case of a metallized film capacitor with a safety mechanism, a vapor deposition film on the metal sprayed portion side is used to improve the adhesion between the metal sprayed portion, which serves as an electrode lead-out portion, and the metallized film. In many cases, the capacitor is made thicker and the other parts are thinner than that, and at least one vapor-deposited film of the pair is divided in the longitudinal direction by the electrode dividing part 70 to form the fuse part 60. When the destruction that cannot be cleared occurs due to the self-recovery action peculiar to the film capacitor, the fuse section 60 is operated by the Joule heat of the short circuit current for clearing the location. However, if the deposition film on the side of the metal sprayed part is thickened,
When the destruction that cannot be cleared occurs because the energy is larger than the other portions, the short-circuit current may continue to flow, and the dielectric breakdown may occur at the portion where the deposited film is thick.

[0006] The present invention solves the above problems, and an object thereof is to improve the characteristics of a metallized film capacitor.

[0007]

In order to achieve the above object, the metallized film capacitor of the first means of the present invention comprises a metallized film having a metal vapor deposition electrode formed on one or both sides of a dielectric film. Electrode lead-out portions are provided on both end faces of a capacitor element that is laminated or wound so that the vapor-deposited electrodes face each other with a dielectric film in between, and the resistance value of the metal vapor-deposited electrode is different from that of the portion in contact with the electrode lead-out portion. The pair of at least one metal vapor deposition electrode is formed so as to be lower than the portion, and a plurality of minute blocks are formed in the longitudinal direction and the width direction of the film, and a fuse portion is provided between adjacent minute blocks. divided with the electrode pattern and structure, and the film longitudinally provided with an electrode separator portion that separates the divided electrode pattern at regular intervals, the adjacent front
In the longitudinal direction between the electrode separators, at least two or more
A small block is provided, and the electrode partitioning portion prevents breakage in minute blocks from sequentially spreading.

Further, in the metallized film capacitor of the second means of the present invention, in addition to the first means, the small block portion of the low resistance film portion having a low resistance value in contact with the electrode lead-out portion has a small block area other than the above. It is smaller than the minute block area of the resistive film portion.

In addition to the second means, the third metallized film capacitor of the present invention has a vapor-deposited metal of zinc or a zinc-aluminum alloy.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION With the above structure, the metallized film capacitor of the first means of the present invention has a plurality of minute blocks formed on one metal vapor deposition electrode in the longitudinal direction and the width direction of the film. A divided electrode pattern with a fuse portion is formed between adjacent minute blocks, and electrode divisions that divide the divided electrode pattern at regular intervals in the longitudinal direction of the film are provided. When it occurs, the current flowing from between adjacent micro blocks suppresses the progress of capacity reduction by operating the fuse part between micro blocks, which does not cause any problem. If does not work, the breakdown in the minute block continues to progress and the dielectric breakdown spreads to the surrounding blocks. It has the effect of preventing the destruction of the entire capacitor with.

Further, in the metallized film capacitor of the second means of the present invention, in addition to the first means, the minute block area of the low resistance film portion contacting the electrode lead-out portion is smaller than the minute block area of the other high resistance film portion. The small size improves the clearing property of the micro-destruction part and improves the operability of the fuse part. Has the function of preventing dielectric breakdown in thick areas.

In addition to the second means, the metallized film capacitor of the third means of the present invention uses zinc or a zinc-aluminum alloy as the vapor deposition electrode, so that the metallized film capacitor can be compared with aluminum alone which is the mainstream of metalized film capacitors at present. Then, by utilizing the metal characteristics that require a small amount of energy to perform clearing at the time of microdestruction, it has the effect of enabling higher potential gradient and smaller size than the aluminum vapor deposition capacitor.

FIG. 1 shows an embodiment of the present invention.
5 through FIG. 1 is a dielectric film made of a plastic film, 2 is the dielectric film 1
2 is a metal vapor-deposited electrode in which an alloy of zinc and aluminum is vapor-deposited on the mesh-shaped divided electrode pattern of any of FIGS. 2 to 4 using a vacuum continuous vapor deposition machine, and 2a is a metal without a divided electrode pattern as shown in FIG. Vapor-deposited electrodes, 3 is a metallized film having a divided electrode pattern and a metallized film having no divided electrode pattern, which are laminated or wound as a pair, or are electrode-sprayed by metal spraying on both end surfaces of a capacitor element, and 4 is the electrode lead-out. The low resistance film portion of the vapor deposition electrodes 2 and 2a vapor-deposited so that the portion in contact with the portion 3 has a lower resistance value than other portions, 5 is the high resistance film portion of the vapor deposition electrodes 2 and 2a , and 6 is the high resistance film portion. An electrode margin portion formed at one end of the resistance film portion 5 is an electrode dividing portion that divides the metal vapor deposition electrode 2 at regular intervals in the longitudinal direction of the film, and the electrode dividing portion 7 is a straight line (FIGS. 2 and 3).
In addition to those described above, the vapor deposition electrode 2 can be divided by a ridge-valley fold line (FIG. 4).

Reference numeral 8 is a minute block of a mesh-like divided electrode pattern of the metal vapor deposition electrode 2, and a plurality of blocks are formed through the fuse portion 9 in the longitudinal direction and the width direction of the film.

Reference numerals 8a and 8b are minute blocks adjacent to the electrode lead-out portion 3, respectively. Since these minute blocks 8a and 8b are smaller than the area of the minute block 8, a minute broken portion is cleared.
The arranging property is improved, and the operability of the fuse part 9 is improved.

In the structure of the metallized film capacitor of the present embodiment, one metal vapor deposition electrode 2 forms a plurality of minute blocks 8 in the longitudinal direction and the width direction of the dielectric film, and the minute blocks 8 are adjacent to each other. A metallized film is used in which a fuse portion 9 is provided and partition portions 7 are formed at regular intervals in the longitudinal direction of the dielectric film 1, and the metal vapor deposition electrode 2a on the other side has both minute blocks and partition portions at regular intervals. A metallized film capacitor with no metallized film is shown. In addition, a pair of metallized films in which both metal vapor deposition electrodes 2 have minute blocks 8 may be used, and these may be laminated or wound to form a metallized film capacitor.

Further, in the embodiment of the present invention, the minute blocks 8a and 8b of the low resistance film portion 4 which are in contact with the electrode lead-out portion 3 have a minute block area smaller than the minute blocks of the other high resistance film portions 5 and thus are minute. There is an advantage that the clearing property of the destruction part is improved and the operability of the fuse part 9 is improved.

Further, in the embodiment of the present invention, the metal vapor deposition electrodes 2 and 2a are made of zinc or a zinc-aluminum alloy, so that a small energy is required to perform clearing at the time of microdestruction, as compared with an aluminum single electrode. Therefore, it has the advantage that high potential gradient and downsizing can be achieved by utilizing the metal characteristics.

[0019]

EXAMPLES Next, the present embodiment will be described in detail using specific numerical values. First, as Example I, an alloy of zinc and aluminum was vapor-deposited on a polypropylene film having a thickness of 6 μm using a vacuum continuous vapor deposition machine. The vapor-deposited film resistance values were 2 to 8 Ω / □ on the metal sprayed portion side and 10 to 30 Ω / □ on the other portions, and a metallized film with a divided electrode pattern and a metallized film without a divided electrode pattern (FIG. 2) were used. To form a wound capacitor. Similarly, as Example II, a metallized film having a divided electrode pattern (FIG. 3) and a metallized film having no divided electrode pattern (FIG. 5) were paired to form a wound capacitor. For comparison, the wound capacitors of Conventional Example I (FIG. 7) and Conventional Example II (FIG. 6) were similarly manufactured.

When the AC voltage step-up test under the maximum allowable temperature + 15 ° C. was carried out similarly to the AC voltage step-up test at the maximum allowable temperature, the results shown in (Table 1) were obtained.

[0021]

[Table 1]

In the AC voltage step-up test in Table 1, the rated voltage was increased by 50 V in 12 hours at the maximum allowable temperature. When the capacitance of the capacitor became almost 0, it was considered that the security mechanism was activated. In this case, Examples I and II,
In the conventional examples I and II, the 100% security mechanism was activated and no difference was obtained in the capacitor characteristics. Therefore, the ambient temperature was further raised by 15 ° C. and the same test was conducted.

At the maximum allowable temperature of + 15 ° C., the present Examples I and II were used.
In the conventional example I, 6 units were destroyed, but in the conventional example II, 2 units were destroyed. In the conventional example I, the breakage points were a breakage in a portion where the vapor deposition film on the side of the metal spray coating was thick and a breakage in a portion where the vapor deposition film was thin in the center. In the conventional example II, all of the fractures occurred at the portion where the vapor deposition film on the metal sprayed portion side was thick. Due to this result, the destruction at the portion where the vapor deposition film on the metal sprayed portion side is thick cannot be cleared because the energy for clearing is larger than that at the other portions,
It is considered that since the short-circuit current continued to flow, the fuse portion 9 generated excessive heat and caused dielectric breakdown. In addition, the breakdown at the thin part of the evaporated film in the center part is that the fuse part does not operate due to the short-circuit current due to clearing of minute breakdown, and the breakdown in that block continues to progress and the dielectric breakdown spreads to the surrounding blocks. It is thought that the capacitor was destroyed.

On the other hand, in the capacitors of Examples I and II, the low resistance film portion 4 in contact with the electrode lead-out portion 3 has a fine block area smaller than other portions, so that the clearing property of the fine fracture portion is improved, and the fuse portion is improved. When the fuse portion 9 does not operate due to a short-circuit current due to clearing of microdestruction, the microblock is also improved because the operability of the device is improved and, at the same time, the security mechanism operates and the electrode delimiters 7 are arranged at regular intervals in the longitudinal direction of the film. It is considered that the breakdown at 8 did not proceed because the breakdown of the capacitor continued to progress and the breakdown of the dielectric spreads to the minute blocks 8 in the periphery to prevent the breakdown of the capacitor.

A self-healing test described in JIS 4908 was conducted on the same sample. The results (Table 2)
Shown in.

[0026]

[Table 2]

It is considered that, as compared with Examples I and II, Conventional Example I had a large divided electrode area with respect to a minute block area, and therefore the fuse was blown by the short-circuit current during self-recovery, leading to a large capacitance phenomenon.

On the other hand, in the conventional example II, although not as great as in the conventional example I, the current flowing from between the adjacent blocks during the self-recovery of a certain minute block also activates the fuse portion between the adjacent blocks having no problem. Therefore, it is considered that the capacity decrease was larger than that in this example. On the other hand, in this embodiment, since the dividing portions are formed at regular intervals in the longitudinal direction of the film, the sneak current at the time of self-recovery can be suppressed, and the fuse operation of a minute block without any problem can be suppressed, and meaningless capacity reduction can be reduced. It was the result.

Further, the low resistance film portion 4 contacting the electrode lead-out portion 3
When the self-recovery occurs in the case, the self-recovery energy is large and the fuse is operated in most cases, leading to a decrease in the capacity. However, in the case of the present Example II, in consideration of this fact, the low contact with the electrode lead-out portion 3 is considered. The resistive film portion 4 is a minute block 8
The capacitance reduction is suppressed by making a and 8b smaller.

[0030]

As described above, since the metallized film capacitor of the first means of the present invention has the electrode dividing portions at regular intervals in the longitudinal direction of the film, it is self-healing and cleared into a plurality of minute blocks. When a micro-breakage that cannot be ringed occurs, the current flowing from between adjacent micro-blocks suppresses the capacity reduction caused by operating the fuse part between adjacent blocks that do not have any problem. When the fuse portion does not operate due to the electric current, it is possible to prevent the destruction of the capacitor due to the fact that the destruction in the minute block continues to progress and the dielectric destruction sequentially spreads to the surrounding minute blocks.

Further, in the metallized film capacitor of the second means of the present invention, in addition to the first means, the low resistance film portion in contact with the electrode lead-out portion has a small block area smaller than other portions and has a clearing property of a minute broken portion. As a result, the operability of the fuse part is also improved, and short-circuit current continues to flow even for damage that cannot be cleared when the vapor-deposited film on the metal sprayed side is thick, and dielectric breakdown occurs at locations where the vapor-deposited film is thick. It can be prevented from causing.

In addition to the second means, the metallized film capacitor of the third means of the present invention uses zinc or a zinc-aluminum alloy as the vapor-deposited metal, so that it can be compared with aluminum alone which is currently the mainstream of metallized film capacitors. Then, by utilizing the metal characteristic that a large amount of energy is required to perform clearing at the time of microdestruction, it is possible to achieve a higher potential gradient and a smaller size than an aluminum vapor deposition capacitor.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a metallized film capacitor according to an embodiment of the present invention.

FIG. 2 is a partial plan view of one metallized film of the same embodiment.

FIG. 3 is a partial plan view of one metallized film having a different divided electrode pattern according to the same embodiment.

FIG. 4 is a partial plan view of one of the metallized films having a different split electrode pattern according to the same embodiment.

FIG. 5 is a partial plan view of the other metalized film of the same embodiment.

FIG. 6 is one of the gold with different split electrode patterns of Conventional Example 1 .
Partial plan view of genusification film

7 is a partial plan view of one metallized film of Conventional Example 2. FIG.

[Explanation of symbols]

1 Dielectric film 2,2a metal deposition electrode 3 Electrode extraction part 4 Low resistance film part 5 High resistance film part 6 electrode margin 7 electrode separator 8,8a, 8b Micro block 9 Fuse part

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Claims (3)

(57) [Claims] 1. Both end surfaces of a capacitor element in which a metallized film having a metal vapor deposition electrode formed on one surface or both surfaces of a dielectric film is laminated or wound so that a pair of metal vapor deposition electrodes face each other with a dielectric film interposed therebetween. An electrode lead-out portion is provided on the metal vapor-deposited electrode, and the resistance value of the metal vapor-deposited electrode is configured so that the value of the portion in contact with the electrode lead-out portion is lower than other portions, and the at least one metal vapor-deposited electrode in the pair is a film. Form a plurality of minute blocks across the length and width,
With a structure divided electrode pattern having a fuse portion between each of the micro blocks adjacent, and the film longitudinally provided with the divided electrode separator unit to separate the electrode pattern at regular intervals in the longitudinal direction between the electrodes separated portions adjacent Very few
A metallized film capacitor having at least two micro blocks, and preventing the destruction in the micro blocks from being successively spread due to the electrode dividing portion. 2. The metallized film capacitor according to claim 1, wherein the micro-block of the low-resistance film portion having a low resistance value contacting the electrode lead-out portion has a micro-block area smaller than the micro-block area of another high-resistance film portion. .. 3. The metallized film capacitor according to claim 2, wherein the vapor-deposited metal is zinc or a zinc-aluminum alloy.