JPH03188611A - Metallized film capacitor - Google Patents

Abstract

PURPOSE:To obtain a metallized capacitor having long life by using one electrode of a metallic thin-film as a split electrode, providing spaces at intervals and selecting the ratio, (the width Lmm of the space)/(AC rated voltage V)>=0.0005. CONSTITUTION:An Al-deposited thin-film is formed onto a polyethylene terephthalate film, etc., and employed as an electrode, and a surface is coated with a thin-film of a lacquer composition. At least one pole of two Al thin-film electrodes 11 is used as a split electrode, and the width of a split electrode groove is brought to Wmm and the width of an electrode space section 12 to Lmm. L/V>=0.0005 is selected in the relationship of with L and the AC rated voltage V of a capacitor. According to the constitution, the deterioration of safety and the reduction of capacitance are prevented, and the lifetime can be prolonged. When W/V>=0.005 holds, the rate of change C/C of capacitance is decreased.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to power capacitors for power factor correction, etc., capacitors for electrical equipment, capacitors for various power supply circuits, capacitors for electronic equipment used in communication equipment, etc. .

[Background Art] In recent years, as electronic devices and the like have become smaller, various electronic components housed therein have been increasingly miniaturized. Various materials and structures are being considered for film capacitors, with the aim of making them smaller and increasing their capacity. For example, it is known that metallizing both sides of a polyester film by aluminum vapor deposition, forming a lacquer layer on the surface, and laminating or winding this to form a metallized film capacitor is one of the methods for making the capacitor smaller and larger. It is being

In addition, to prevent secondary disasters such as ignition or explosion in the event of a capacitor malfunction, oil-impregnated capacitors with metal cases are now equipped with safety devices, and dry-type capacitors are now equipped with safety devices. Security mechanisms have also been installed. In such a security mechanism that has been proposed in the past, at least one electrode (evaporation electrode) is a split electrode, and intermittent vapor deposition blanks are provided in this split electrode (Japanese Patent Application Laid-Open No. 58182
No. 216, No. 57-154823, No. 58-
No. 10311, No. 57-21.0617, etc.).

[Problems to be Solved by the Invention] However, with the above-mentioned conventional technology, there is a reduction in security due to insufficient pressure resistance on the creeping surface between the electrodes that are separated by the vapor deposition electrode blank space, and a problem that occurs between the divided electrodes adjacent to the vapor deposition electrode groove. There was a problem in that capacity decreased during long-term use due to insufficient pressure resistance along the creeping surface.

SUMMARY OF THE INVENTION In order to solve the problems of the prior art described above, it is an object of the present invention to provide a metallized capacitor that prevents deterioration in safety, prevents capacity reduction during long-term use, and improves lifespan.

[Means for Solving the Problems] In order to achieve the above object, the present invention has the following configuration. That is, it is a metallized film capacitor including two opposing metal thin film electrodes formed on the surface of a base film, in which at least one of the two metal thin film electrodes is constituted by a split electrode. At the same time, intermittent electrode blank parts are provided in the divided electrodes, and the width L of the electrode blank parts is
(unit: 2 mm) and the AC rated voltage V (unit: VAC) of the capacitor is set to L/V≧0.0005.

In the present invention, in addition to the above configuration, the relationship between the width W (mm) of the divided electrode groove of the divided electrode and the AC rated voltage V (unit: VAC) of the capacitor is determined such that W/V≧0.00.
05 is preferable.

[Function] According to the configuration of the present invention described above, at least one metal thin film electrode of the metallized film capacitor including two metal thin film electrodes is constituted by a split electrode, and the split electrode is provided with an intermittent electrode. A blank area is provided, and the relationship between the width of the electrode blank area and the ACC rated voltage color of the capacitor is determined by L/V≧0.
．． Since it is set to 0005, it prevents deterioration of security and
It is possible to prevent capacity reduction during long-term use and improve lifespan.

Furthermore, in addition to the above configuration, the relationship between the width W of the vapor deposition electrode dividing groove and the ACC rated voltage color of the capacitor is determined as W/V≧0.0.
By setting it to 005 or more, the capacitance change rate (△C/
C) The decrease is small, and capacity decrease during long-term use can be prevented.

[Example] The present invention will be explained in more detail below using Examples.

Note that the present invention is not limited to the following examples.

FIG. 1 shows the metallized film of this example.

In FIG. 1, reference numeral 11 denotes a metal thin film such as vapor-deposited metal provided on the surface of the base film.

Reference numeral 12 denotes an electrode blank portion provided in the metal thin film 11. 1
3 is a divided electrode groove. L is the width of the electrode blank area (unit: m
m), and W is the width (unit: mm) of the divided electrode groove.

A manufacturing example of the metallized film having the above structure will be described below. As the film base material, resin films such as polyethylene terephthalate film, polypropylene film, polyphenylene sulfide film, polyimide film, and polyimide amide film can be used. As the metal thin film, a vapor deposited film such as A/ can be used. The deposited film functions as an electrode. A lacquer composition may be applied to the surface of this vapor-deposited film to a dry thickness of about 1 μm.

Example 1 A capacitor with an AC rated voltage of 400 V (volts) and 50 μF was prepared using single-sided vapor-deposited polypropylene films (thickness: 6 μm and 8 μm, width: 80 mm) as samples.

The width of the vapor deposition electrode blank part was 0.005 mm, 0.
．． 1mm, 0.15mm, 0.2mm.

Q, 3mm samples were created. Further, the width W of the divided electrode groove was generally 0.3 mm. The ratio L/V between the width L (mm) of the vapor deposition electrode blank part and the AC rated voltage (VAC) of the capacitor in this sample is as follows.

Width L of electrode blank area (mm) L/V value 0. 0
5 0.0001250, 1
0.000250, 15
0. [1003750, 20,0005 0, 30,00075 Safety Test Measured according to JIS-C-49081m. The results are shown in Table 1.

Table 1 As is clear from Table 1, regardless of the thickness of the dielectric film, samples in which the ratio L/V between the width L (mm) of the blank area of the vapor-deposited electrode and the AC rating of the capacitor is 0.0005 or more It was confirmed that the pass rate was high for experiment number 4.
5).

On the other hand, the reason why the pass rate of Experiments Nos. 1 to 3 was unfavorable was that the voltage applied between the electrodes that separated the blank area of the evaporation electrode after the fuse was blown caused a layer short in the blank area of the electrode. It is thought that insulation deterioration in the vicinity progressed, leading to breakdown.

Example 2 A capacitor with an AC rated voltage of 400 V and 50 μF was prepared using a single-sided vapor-deposited polypropylene film (thickness: 6 μm, width: 80 mm) as a sample.

Then, the width W of the divided electrode is 0.05 mm, 0°1 mm,
Samples of 0.15 mm, 0.2 mm, and 0.3 mm were prepared and subjected to a continuous durability test. At this time, the width of the blank part of the vapor deposition electrode was uniformly set to 0°3 mm. The measurement conditions are:
AC300V was applied in a constant temperature bath with an atmosphere at a temperature of 0°C, and the rate of change in capacitance (ΔC/
C) was investigated. Capacitance change rate after 1000 hours (△C
/C) is shown in Figure 2.

Next, a sample was prepared in the same manner as above except that the thickness of the polypropylene film was changed to 8 μm, and a continuous durability test was conducted. The capacitance change rate (ΔC/C) of this sample after 1000 hours is shown in FIG.

As is clear from Figures 2 and 3, regardless of the thickness of the dielectric film, if the width W of the vapor-deposited electrode dividing groove is 0.2 mm or more (W/V value is 0°0005 or more), It was confirmed that the rate of change in capacitance (ΔC/C) after 1,000 hours decreased little, and that a decrease in capacity could be prevented.

On the other hand, the width W of the vapor deposition electrode dividing groove is less than 0.2 mm (
Samples with a W/V value of less than 0.0005 were not preferable due to a large capacity decrease. The reason for this is that if the fuse part blows out for some reason, voltage will be applied between the separated electrode part adjacent to the evaporation electrode groove and the unseparated electrode part, resulting in a layer short between the evaporation electrode grooves. It is thought that the fuse in the adjacent electrode section blown out, causing the capacity to decrease.

Example 3 In order to confirm a layer short due to insufficient withstand voltage on the creeping surface between the electrodes that separated the blank part of the evaporation electrode, the AC rated voltage was changed using a capacitor similar to Example 1 using a polypropylene film with a thickness of 6 μm. A safety test was conducted.

The results are shown in Table 2.

As is clear from Table 2, even though the rated voltage was set to a low value, samples with L/V values of less than 0.0005 showed a low safety success probability in the safety test. In addition, all of the failure points of the rejected samples were layer shorts in the vacuum deposition areas. As can be seen from this, it was confirmed that a layer short due to insufficient creepage withstand voltage between the electrodes separated by the vacuum electrode blank area occurs when the L/V value is less than 0.0005.

[Effects of the Invention] As explained above, according to the present invention, at least one metal thin film electrode of a metallized film capacitor including two metal thin film electrodes is constituted by a split electrode, and the split electrode is intermittently An electrode blank part is provided, and the relationship between the width of the electrode blank part and the ACC rated voltage color of the capacitor is determined as L/V≧
By setting the value to 0.0005, it is possible to achieve the special effects of preventing deterioration in safety, preventing capacity reduction during long-term use, and improving service life.

Furthermore, in addition to the above effects, the relationship between the width W of the vapor deposition electrode dividing groove and the ACC rated voltage color of the capacitor is determined as W/V≧0.0.
By setting it to 005 or more, the capacitance change rate (△C/
C) The decrease is small, and capacity decrease during long-term use can be prevented.

[Brief explanation of drawings]

FIG. 1 is a developed view of a capacitor showing an embodiment of the present invention, and FIGS. 2 and 3 are characteristic diagrams showing capacitance changes during testing of the embodiment of the present invention. 11: Metal thin film 1.2: Electrode blank area 13: Divided electrode groove L: Width W of the electrode blank area: Width of the divided electrode groove 11: Metal thin film 12/electrode blank area 13: Divided electrode groove L: Width of the electrode blank area Width W: Width of the divided electrode groove Width W of the divided electrode groove (unit: mm) (The value in parentheses represents W/V) Fig. 3

Claims (2)

[Claims] (1) A metallized film capacitor including two opposing metal thin film electrodes formed on the surface of a base film, in which at least one of the two metal thin film electrodes is configured as a split electrode. At the same time, intermittent electrode blank parts are provided in the divided electrodes, and the width L (unit: mm) of the electrode blank part and the AC rated voltage V (unit: VA
A metallized film capacitor characterized in that the relationship with C) is L/V≧0.0005. (2) The relationship between the width W (mm) of the divided electrode groove of the divided electrode and the AC rated voltage V (unit: VAC) of the capacitor is expressed as W
2. The metallized film capacitor according to claim 1, wherein /V≧0.0005.