JPH07142284A - Metallized film capacitor - Google Patents

Abstract

PURPOSE:To enhance the operation of safety function, and improve the reliability of a capacitor, by specifying the dimension of a cow neck type constriction part of a peninsula type metallized film. CONSTITUTION:A peninsula type metallized film 1 and a base side metal film which has no insulating trenches 4 in an evaporation film are so stacked and wound that insulation margin parts 3 become opposite. By spraying metallikon metal on both ends, electrode extraction parts are formed in a capacitor element, which is sheathed to manufacture a metallized film capacitor. In this case, the dimensions (a) and (b) of a cow neck constriction part 5, which a peninsula type metallized electrode 2 has, satisfy a relation a<b. That is, the dimension (b) of the constriction part 5 is set larger than the dimension (a). Thereby the faulty current generated at the time of dielectric breakdown of a capacitor is effectively blocked only by the faulty electrode before multilayer breakdown of dielectrics, and high reliability safety function can be realized.

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 having a safety function by forming a plurality of insulating grooves in the lengthwise direction of a vapor deposition electrode of the metallized film capacitor to form partition electrodes. MF capacitor) of the above).

[0002]

2. Description of the Related Art A vapor deposition electrode is divided into a plurality of lengthwise directions of a dielectric film by an insulating groove, and a cow-neck-shaped narrowing portion as shown in FIG. 1 is provided to form a peninsula-shaped vapor deposition electrode. The conventional metallized film capacitor (hereinafter referred to as the conventional MF capacitor) with a fuse function added to the capacitor has a large difference in the performance of the security function depending on the type of the dielectric film, the metal of the deposited film and the value of the deposited film resistance. Was there.

For this reason, in the metallized film having the above-mentioned segmented electrode structure, the distance between the dielectric films of the T-shaped or inverted L-shaped insulating grooves in the longitudinal direction is changed, and a plurality of cow-neck-shaped constricted portions of the peninsular deposition electrode are formed. Although the security function performance has been improved by dividing it into two parts, none of the methods had the expected effect.

[0004]

The problem to be solved by the present invention is to improve the operability of the safety function of the above-mentioned conventional MF capacitor having a sectional electrode structure and to improve the reliability of the capacitor.

[0005]

SUMMARY OF THE INVENTION The present invention provides a metallized film capacitor having improved safety function operability in order to solve the above-mentioned problems. It is a peninsular metallized film shown in FIG. Under the condition that the dimension ratio of the width dimension a and the length dimension b of the narrowed portion satisfies the relationship of a <b, the electrical resistance of the cow's neck-shaped narrowed portion is increased and a fault overcurrent is generated in the one-section electrode forming the capacitor. When flowing, the amount of heat (Joule heat) generated in the cow's neck-shaped constriction is increased, so that the failure current of the capacitor can be interrupted quickly and reliably.

That is, a vapor deposition electrode is formed by providing an insulating margin portion at the end of the dielectric film in the width direction, and a plurality of T-shaped or inverted L-shaped insulating grooves are provided in the longitudinal direction of the dielectric film to provide a cow's neck. Peninsular metallized film with a narrowed portion and the other metallized film without the insulating groove are wound so that the insulation margins are opposite, and the metallikon metal is sprayed on both ends. A metallized film capacitor having a capacitor element formed with an electrode lead-out portion, which is provided with a condition that the dimensions a and b of the cow-neck-shaped narrowed portion of the peninsular metallized film satisfy the relationship of a <b. It is a metallized film capacitor.

The metallized film capacitor is characterized in that the metallized film vapor-deposited metal is zinc (Zn) or aluminum (Al) or a mixture thereof. The metallized film capacitor is characterized in that the material of the dielectric film is polypropylene (PP) or polyethylene terephthalate (PET).

[0008]

As shown in FIG. 1, if the dimensions a and b of the cow neck-shaped narrowed portion 5 of the peninsular metallized film 1 satisfy the condition of a <b, and the dimension b is made longer than the dimension a, the cow neck shape is obtained. The electrical resistance of the narrow portion 5 increases, and the amount of heat generated (Joule heat) generated in this portion increases. That is,

[0009]

[Equation 1]

And the current I (A) of the cow's neck-shaped constriction 5
Alternatively, by increasing the electric resistance R (Ω), the power loss P (W) generated in the portion is increased, more Joule heat is generated, and the operation performance of the safety function of the MF capacitor of the present invention is improved. .

The shape of the cow neck-shaped constriction portion 5 is not limited to that shown in FIG. 1 but also the shapes of the embodiments shown in FIGS. 2 to 7. The shape of the cow neck-shaped constriction portion 5 is not particularly limited and can be selected. Are free, and these cow neck-shaped constrictions 5 may be appropriately combined, and the effects are the same.

[0012]

EXAMPLES Examples of the MF capacitor of the present invention will be described below. A peninsular metallized film 1 shown in FIG.
Base side metallized film 6 having no insulating groove 4 in the vapor deposition film
And are wound so that the insulation margin portions 3 are opposite to each other and wound, and the capacitor element 8 having the electrode lead-out portions 7 formed by thermally spraying the metallikon metal on both ends thereof is externally packaged.
I made a capacitor.

The capacitor thus manufactured has the following rating,
Each sample was compared and evaluated by a safety test defined in JIS C4908 for 250 samples. Rating of capacitor: Rated voltage 250VAC, rated capacity 30μF

In the above MF capacitor, as shown in Table 1, the sample classification of the metallized film was classified into five samples of sample symbols A to E in which the combination of the dielectric film and the vapor-deposited metal was classified.

[0015]

[Table 1]

Further, as to the dimensions a and b of the cow-neck-shaped narrowed portion 5 of the vapor-deposited metal, as shown in Table 2, the dimension a is the sample No. 1 to 5 for 1.0 mm, sample No. 6-10 to 0.
8 mm, sample No. 11 to 15 are set to 3 levels of 0.6 mm, and the dimension b is the sample No. 1 to 5 for 1.3 to 0.5 mm
Sample No. Sample No. 6 to 10 to 1.2 to 0.4 mm. 11 to 15 were divided into five stages of 1.1 to 0.3 mm, and each sample was compared and evaluated.

[0017]

[Table 2]

The evaluation tests and the results of the examples are shown in Table 3. First, regarding the combination of the evaluation tests, the sample sections A and C of the metallized film described above have the dimensions a and b of the cow neck-shaped constriction 5. Sample No. 1 to 10, and sample sections B, D, and E are sample Nos. It was set as each test of 6-15.

[0019]

[Table 3]

The reason why all the combinations are not carried out in the above-mentioned test is that even if a security function test is carried out, it is difficult to operate from the beginning due to the characteristics of the vapor-deposited metal of the metallized film and the operability is easy. However, the combination of regions that are difficult to match the life characteristics is excluded.

The evaluation of the results of the test by the above combination is shown in Table 3. According to this result, the dimensions a and b of the cow neck-shaped constriction 5 satisfy the relationship that the ratio of a and b is a <b. It was confirmed that 100% operability was obtained for the security function under the conditions.

Further, the dimensions a and b of the cow neck-shaped narrowed portion 5
From the results of this test, it was also clarified that the operability of the safety function is reduced as the dimensional ratio of a becomes not less than a = b, but the condition of a> b.

[0023]

As is apparent from the results of the above-described embodiments, the MF capacitor of the present invention has the dimensions a and b of the cow neck-shaped constriction 5 of the peninsular metallized electrode 2 as shown in FIGS. If the condition that satisfies the relationship of a <b is satisfied, that is,
By making the dimension b of the cow neck-shaped narrowed portion 5 longer than the dimension a and effectively increasing the electric resistance, the power loss (generation of Joule heat) generated in the portion can be increased. .

As a result, the failure current generated when the dielectric of the capacitor is destroyed is effectively cut off by disconnecting only the defective electrode until the dielectric breakdown between layers occurs, and the conventional MF is used.
The requirement for high reliability and safety function, which has been a technical problem of capacitors, can be realized by the MF capacitor of the present invention, which is industrially and practically valuable.

[Brief description of drawings]

FIG. 1 is an explanatory view of a pattern main part of an embodiment of a peninsular metallized film having T-shaped insulating grooves according to the metallized film capacitor of the present invention.

FIG. 2 is an inverted L according to the metallized film capacitor of the present invention.
It is explanatory drawing of the pattern principal part of the Example of the peninsular metallized film which has a shape insulation groove.

FIG. 3 is an explanatory diagram of a pattern main part of another embodiment of a peninsular metallized film having a T-shaped insulating groove according to the metallized film capacitor of the present invention.

FIG. 4 is an explanatory diagram of a pattern main part of another embodiment of a peninsular metallized film having a T-shaped insulating groove according to the metallized film capacitor of the present invention.

FIG. 5 is an explanatory diagram of a pattern main part of another embodiment of a peninsular metallized film having a T-shaped insulating groove according to the metallized film capacitor of the present invention.

FIG. 6 is an explanatory view of a pattern main part of another embodiment of a peninsular metallized film having a T-shaped insulating groove according to the metallized film capacitor of the present invention.

FIG. 7 is an explanatory diagram of a pattern main part of another embodiment of a peninsular metallized film having a T-shaped insulating groove according to the metallized film capacitor of the present invention.

FIG. 8 is a partially disassembled perspective view of a capacitor element of the metallized film capacitor of the present invention.

[Explanation of symbols]

 1. Peninsular metallized film 2. Evaporated film electrode 3. Insulation margin section 4. Insulation groove 5. Cow neck narrow part 6. Base side metallized film 7. Electrode extraction part 8. Capacitor element

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[Procedure amendment]

[Submission date] December 27, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

[0015]

[Table 1]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction content]

The evaluation of the results of the test by the above combination is shown in Table 3. According to this result, the dimensions a and b of the cow neck-shaped constriction 5 satisfy the relationship that the ratio of a and b is a <b. It was confirmed that 100% operability was obtained for the security function under the conditions. Then, the sample No. in which the dimensional conditions of the cow neck-shaped narrowed portions a and b are a: b = 1: 1.1 or more. 100% operability was obtained for all of 1, 2, 6, 7, 11, 12, and 13.

Claims (1)

[Claims] 1. A vapor deposition electrode is formed by providing an insulating margin portion at an end portion in the width direction of a dielectric film, and a plurality of T-shaped or inverted L-shaped insulating grooves are provided in the longitudinal direction of the dielectric film. A peninsula metallized film with a cow neck-shaped constriction and the other metallized film that does not have the above-mentioned insulation groove are overlapped and wound so that the insulation margins are opposite, and the metallikon metal is sprayed on both ends. In the metallized film capacitor with the capacitor element having the electrode lead-out portion formed thereon, the width dimension a and the length dimension b of the cow-neck-shaped narrowed portion of the peninsular metallized film satisfy the condition of a <b. A metallized film capacitor characterized by being provided.