JPH1126281A - Metallized film capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the withstand voltage of a capacitor by making segmentation of a metal evaporation electrode with an insulation slit easy, and improving reliability of operation of a fuse part provided between segments, in a metallized film capacitor. SOLUTION: A metal evaporation electrode 5 of a film 1, constituting a metallized film capacitor is divided into a large number of segments 6 with insulation slits, 2, 3 and 4 not in the width direction of the film 1, and a fuse part 9 is formed at a meeting point of the insulation slits 2, 3 and 4 in three directions by metal evaporation, and each of insulation slits 2, 3 and 4 is ended at the fuse part 9 rounded, and the area of the segment 6 is made 25-900 mm<2> .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metallized film having a metal-deposited electrode divided into a plurality of segments and having a self-recovery function and a security mechanism, for electric power, charge / discharge or DC filter. The present invention relates to a high-voltage capacitor.

[0002]

2. Description of the Related Art Conventionally, high-voltage capacitors for electric power, charging / discharging or filters use insulating paper or plastic film as a dielectric, or a combination of insulating paper and plastic film, and aluminum as an electrode. A foil electrode type capacitor has been used in which a foil is used and the dielectric and electrode foil are alternately stacked and wound to form a capacitor element. In some cases, a metalized paper or metalized film on which metal is deposited is used instead of the aluminum foil electrode.

[0003]

The dielectric of a foil electrode type capacitor is as thin as several μm to several tens μm and has a large area. Therefore, if the dielectric contains an insulation defect, the dielectric is locally broken down. However, since there is no self-healing function, it is necessary to design in consideration of the defective portion. For this reason, in the conventional design, a method has been adopted in which several dielectrics are overlapped to compensate for a minute defect portion of one dielectric by another dielectric. In this method, the effect was increased as the number of superposed dielectrics increased.However, the thickness between the electrodes was increased, and the disadvantages were that the external dimensions increased, corona was easily generated, and the life of the capacitor was shortened. was there.

Further, in a metallized film capacitor, even if a local dielectric breakdown occurs, the insulation is restored by a self-healing function by scattering of the metal deposition electrode. However, the high-voltage capacitor mainly has a pressure switch protection method by increasing the internal pressure of a container housing the capacitor element as protection at the time of dielectric breakdown, and thus has a drawback that the higher the voltage, the more difficult it is to protect.

For this reason, in a metallized film capacitor disclosed in Japanese Patent Application Laid-Open No. 6-310368, a metal deposition electrode is divided into small portions by grid-like insulating slits, and a fuse portion crossing the insulating slit between adjacent segments. The purpose of the fuse effect is to secure the self-recovery action of the metallized film and the reliability against dielectric breakdown, and to minimize the capacity decrease due to the fuse operation, etc., but in the width direction of the metallized film. In the insulating slit,
Since it is difficult to completely eliminate metal deposition, productivity and yield have been impaired.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks, and has been made by improving the above-mentioned insulating slit, and improving the security function and the fuse effect to recover the insulation at the time of dielectric breakdown at the defective portion of the metallized film. The aim is to provide a compact and lightweight high-voltage capacitor.

[0007]

According to the metallized film capacitor of the present invention, a metallized film having a metallized electrode on one side or a metallized film having a metallized electrode on both sides and an insulating film are superposed. Or two metalized films with metallized electrodes on one side and two
Winding what is obtained by alternately superimposing two insulating films and providing an electrode lead portion by spraying metal on both winding end surfaces, at least one of the metal-deposited electrodes is not in the width direction of the film. It is divided into a number of hexagonal segments by three-way insulating slits.

At all six vertices of a hexagonal segment, or at three other vertices,
A fuse portion is formed by a metal deposition layer constituting the electrode at a gathering point where the insulating slits are gathered from three directions, and each fuse portion connects three segments arranged therearound to each other. ing. The ends of each of the insulating slits in these fuse portions are rounded and terminated.

In the above-described capacitor, when a defective portion exists in the film as in the case of the conventional metallized film capacitor, discharge occurs through the defective portion, and the discharge causes the surrounding metal deposition electrode to evaporate. It is. If the discharge for self-healing becomes large-scale so as to penetrate several layers of the film, the fuse around the segment including the defective portion is blown to limit the discharge current. As a result, the discharge scale can be kept to a minimum, so that a decrease in the capacitance of the capacitor due to the discharge at the defective portion can be suppressed. And since there is no thing in the width direction of the film in the insulating slit, it is possible to form an insulating slit that functions well even if the width is small, and the end of each insulating slit in the fuse portion is rounded. Thus, the fusing current of each fuse portion can be accurately defined.

[0010] The area of each segment is preferably small in order to suppress the discharge current at the defective portion, but if it is excessively small, the ratio of the area of the insulating slit becomes large, so that the area of 25 mm ² or more is appropriate. Moreover, when the excessively large area of each segment, the loss of capacitance due to a single fuse operation increases, it is appropriate 900 mm ² or less.

It is desirable that the width W _{2 of the} insulating slit and the width W ₁ of the narrowest portion of the fuse portion have substantially the same value. If each segment has a fuse unit three by three, the insulating slit width W ₂ and the fuse unit width W ₁ are both 0.2 to 2.0
mm is suitable, if each segment has a fuse unit by six, the insulating slit width W ₂ and the fuse unit width W ₁ are both appropriate 0.2～1.75Mm. Also,
The film resistance value of the metal vapor deposition layer in each segment and each fuse portion is suitably 6 to 40Ω / □, and the film resistance value in the side edge portion where the metal vapor deposition electrode is connected to the electrode lead-out portion is 2 to 10Ω. / □ is appropriate.

At a side edge portion where the metal-deposited electrode is connected to the electrode lead-out portion, a band-shaped conductive path continuous in the longitudinal direction of the film is formed by a metal-deposited layer constituting the electrode. Therefore, even if there is insufficient contact between the metal deposition electrode and the electrode lead portion, it is possible to maintain the electrical connection between the two and to prevent a large charge / discharge current from interrupting the electrical connection between the two. Can be prevented.

As described above, according to the present invention, the potential gradient of the film can be safely increased so that the rated voltage of the capacitor can be set high, or the size of the capacitor can be reduced.
It can contribute to weight reduction. Further, it is possible to realize a capacitor suitable for severe use such as power, charge / discharge, and DC filter with a large charge / discharge current.

[0014]

DETAILED DESCRIPTION OF THE INVENTION The capacitor of the present invention has two metallized films having metallized electrodes on one side or one metallized film having metallized electrodes on both sides. Appropriate materials such as a polypropylene film and a polyethylene terephthalate film can be used as the material of these films, and appropriate materials such as zinc, aluminum, and a mixture of zinc and aluminum can be used as the metal to be deposited.

As shown in FIGS. 1 to 4, at least one of these metal-deposited electrodes has insulating slits 2, 2,...
.. And 4, 4,.
Are divided into hexagonal segments 6, 6,.... In the illustrated example, the insulating slits 2, 2,... Are in the longitudinal direction of the film 1, and the insulating slits 3, 3,.
, And 4 make an angle of about 120 ° with the insulating slits 2, 2,. Segment 6,
The shape of 6... Is appropriate, such as a regular hexagon, a hexagon long in the longitudinal direction of the film, and a hexagon long in the width direction of the film, but is desirably arranged in a regulated manner. Each insulating slit is formed by not depositing metal on the film.

It is desirable that a band-shaped energizing path 7 which is continuous in the longitudinal direction of the film is formed on one side edge of the film by the metal vapor deposition without providing an insulating slit.
It is desirable that the metal deposition layer in the belt-like current path 7 be thicker than the segments 6, 6,.... On the other side edge of the film 1, an insulating margin 8 on which no metal deposition is performed is continuously formed in the longitudinal direction of the film.

At each vertex of the hexagonal segment 6,
The insulating slits 2, 3, and 4 in three directions are gathered in a star shape. Every third of these meeting points, or 6
In all of the locations, the fuse part 9
.. Are formed, and each fuse portion electrically connects the three segments 6, 6, 6 arranged so as to surround each other. The end of each of the insulating slits 2, 3, and 4 in each fuse section 9 terminates in a rounded shape such as a semicircle. The insulating slits 2, 3,
At the point where the fuse portion 9 is not formed at the gathering point 4, the insulating slits are connected to each other.

FIGS. 1 and 2 show each segment 6, 6...
3 shows a case where each segment 6, 6... Is a hexagon long in the longitudinal direction of the film 1. FIG. FIGS. 1 and 3 show the case where the fuse portions 9 are provided at three places around each segment 6, and FIGS. 2 and 4 show the case where the fuse portions 9 are provided at six places around each segment. Show the case.

In the case of the films 10 and 10 having the metal-deposited electrodes on one side as described above, the films 10 and 10 may be overlapped and wound as shown in FIG. 5A, or may be wound as shown in FIG. 10 and insulating films 11 and 11 are alternately stacked and wound, and a film 12 having metal-deposited electrodes on both surfaces
In the case of (1), as shown in FIG. 5 (c), the insulating film 11 and the insulating film 11 are superposed and wound, and as shown in FIG. It is assumed to be 14. In this case, the films 10, 10
, Or one of the metal-deposited electrodes on both surfaces of the film 12 does not necessarily have to be divided into segments 6, 6,... As shown in FIGS. However, on one side edge, there is a band-shaped conduction path 7 made of a thick metal vapor deposition layer, and on the other side edge, there is an insulation margin 8.

The above-described capacitor element 14 is shown in FIG.
6B or an appropriate number is connected in series, parallel, or series-parallel as shown in FIG.
The product is housed in a container 17 having 5 and 16 and filled with an insulating agent 18 as needed to obtain a product.

Example 1 A test capacitor was manufactured according to the following specifications from a pair of metallized films having the metal deposition pattern shown in FIG. -Metallized polypropylene film: 12 m, 100 m
m width ・ Zinc deposited film resistance value: band-shaped current path 2Ω / □, segment part and fuse part 6Ω / □ ・ Segment area: 101.9mm ²・ Fuse part size (W ₁ ): 1.0mm ・ Insulation slit width ( W ₂ ): 1.0 mm ・ Capacitor capacity: 12 μF ・ Insulating agent: rapeseed oil ・ Container: square tin case ・ Number of samples: 10

The test method is a cumulative overvoltage test, in which a DC voltage 1 equivalent to 125 V / μm is applied to a test capacitor at room temperature.
500 V is applied for 24 hours, and the capacitance of the capacitor is measured at 1 KHz after the application. Next, a voltage of 1800 V corresponding to 150 V / μm is applied in the same manner, and thereafter the capacitance is measured. Thereafter, the measurement is sequentially repeated while increasing the applied voltage by 300 V (25 V / μm), and the applied voltage becomes 480.
The test was performed until the voltage reached 0 V (400 V / μm) to evaluate the rate of change in capacitance. FIG. 7 shows the test results.

According to the test results, the dielectric potential gradient was 15
From 0 to 300 V / μm, there is almost no change in the capacitance.
2.5% at 5 V / μm, 6% at 350 V / μm, 375
The capacity was reduced by 12% at V / μm and by 24% at 400 V / μm. Therefore, the rated voltage of the capacitor is 4080 V
It was confirmed that the capacity reduction could be kept to 5% or less if the dielectric potential gradient was set to be equal to or less than 340 V / μm.

Example 2 Using two metalized films having the metal deposition pattern shown in FIG. 1 (three fuses around each segment), a test capacitor was manufactured according to the following specifications. -Metallized polypropylene film: 12 m, 100 m
m width ・ Zinc deposited film resistance Strip-shaped current path: 1, 2, 3, 5, 10Ω / □ Segment part and fuse part: 5, 6, 10, 15, 2
0, 30, 40Ω / □ ・ Segment area: 101.9 mm ² , 122.3 mm
^2. Fuse size (W ₁ ): 0.1, 0.2, 1.
0, 2.0, 2.5 mm ・ Insulation slit width (W ₂ ): 0.1, 0.2,
1.0, 2.0, 2.5mm ・ Capacitor capacity: 12μF ・ Insulating agent: Rapeseed oil ・ Container: Square tin case ・ Number of samples: 5 types, 19 types, total 95

The test method is a continuous DC conduction test at 70 ° C.
DC voltage of 3375V in a hot air circulation type thermostat of 400
0 hour continuous application, capacitance change rate after voltage application and ta
An evaluation was made for nδ. The test results are shown in Table 1 and FIGS.

[0026]

[Table 1]

From the test results, the following has been found. When the resistance value of the deposited film is 2 to 10 Ω / □ in the belt-shaped current path and 6 to 40 Ω / □ in the fuse portion and the segment portion, if the fuse portion width W ₁ is 0.2 to 2.0 mm, the capacitance change rate And tan δ are both good, but if the fuse portion width W ₁ is as small as 0.1 mm, the fuse portion is liable to be blown and the capacity is reduced to 5% or more, which is not preferable. When the distance is as large as 5 mm, the operability of the fuse deteriorates, and tan δ increases. Although the fuse unit width W ₁ is desirably equal to the insulating slit width W ₂ in terms of stability and production operations, the fuse unit width W
_{When 1} is as small as 0.1 mm, the insulating slit width W ₂ also becomes narrow, which causes a problem in insulation. On the contrary, when the fuse section width W ₁ is as large as 2.5 mm or more, the insulating slit width W ₂ is also large. Therefore, the segment area is reduced, which is disadvantageous in terms of material utilization efficiency.

Further, the fuse portion width W ₁ is set to an appropriate value of 1.0.
mm, the thickness of the metal deposition film in the fuse portion is large when the film resistance value of the metal deposition electrode is relatively low at 1 Ω / □ in the belt-like current path and 5 Ω / □ in the segment portion and the fuse portion. Operability of the fuse part is deteriorated because
anδ increases. Conversely, when the film resistance is 12
Ω / □ or more, 50Ω / □ at segment and fuse
If the above is relatively high, the thickness of the metal deposition film itself is extremely thin, so that the stability of the film resistance value is poor, and the productivity and yield are undesirably reduced.

Therefore, the fuse portion of each segment is shown in FIG.
In the case of three, as shown in the figure, the resistance of the deposited film of the segment part and the fuse part is 6 to 40Ω / □, and the fuse part width W
If ₁ and the insulating slit width W ₂ is 0.2 to 2.0,
It was found that both the capacity change rate and tan δ were good.

Example 3 A test capacitor was manufactured according to the following specifications from a pair of metallized films having the metal deposition pattern shown in FIG. 2 (the number of fuses around each segment was six). -Metallized polypropylene film: 12 m, 100 m
m width ・ Zinc deposited film resistance Strip-shaped current path: 1, 2, 3, 5, 10Ω / □ Segment part and fuse part: 5, 6, 10, 15, 2
0, 30, 40Ω / □ ・ Segment area: 101.9 mm ² , 122.3 mm
^2. Fuse size (W ₁ ): 0.1, 0.2, 1.
0, 1.75, 2.0mm · insulating slit width _{(W 2): 0.1, 0.2} ,
1.0, 1.75, 2.0mm ・ Capacitor capacity: 12μF ・ Insulating agent: Rapeseed oil ・ Container: Square tin case ・ Number of samples: 5 types, 95 each type

The test method is a continuous DC conduction test at 70 ° C.
DC voltage of 3375V in a hot air circulation type thermostat of 40
The capacitance change rate and ta after voltage application for 00
An evaluation was made for nδ. The test results are shown in Table 2 and FIGS.

[0032]

[Table 2]

The following was found from the test results. When the resistance value of the deposited film is 2 to 10 Ω / □ in the band-shaped current path and 6 to 40 Ω / □ in the fuse portion and the segment portion, if the fuse portion width W ₁ is 0.2 to 1.75 mm, the capacitance change rate And tan δ are both good, but when the fuse portion width W ₁ is as small as 0.1 mm, the fuse portion is liable to be blown and the capacity is reduced to 5% or more, which is not preferable. If it is as large as 0 mm, the operability of the fuse deteriorates, and tan δ increases. Further, since when the fuse unit width W ₁ is small and 0.1mm becomes narrower insulating slit width W _2, the resulting problems in the insulating reverse when the fuse unit width W ₁ is as large as more than 2.0mm insulating because the slit width W ₂ becomes larger, the segment area is disadvantageous in terms of efficiency of use of reduced materials.

The fuse width W ₁ is set to an appropriate value of 1.0.
mm, the thickness of the metal deposition film in the fuse portion is large when the film resistance value of the metal deposition electrode is relatively low at 1 Ω / □ in the belt-like current path and 5 Ω / □ in the segment portion and the fuse portion. Operability of the fuse part is deteriorated because
anδ increases. Conversely, when the film resistance is 12
Ω / □ or more, 50Ω / □ at segment and fuse
If the above is relatively high, the thickness of the metal deposition film itself is extremely thin, so that the stability of the film resistance value is poor, and the productivity and yield are undesirably reduced.

Therefore, the fuse portion of each segment is shown in FIG.
In the case of six pieces, as shown in FIG. 6, if the resistance of the deposited film of the segment part and the fuse part is 6 to 40 Ω / □ and the width of the fuse part is 0.2 to 1.75 mm, the capacity change rate and tan
It was found that both δ were good.

[0036]

As described above, according to the present invention, when a metallized electrode in a metallized film capacitor is divided into a number of segments, an insulating slit which is not in the width direction of the film is used. In the fuse section that connects the segments with good yield, the end of each insulating slit is rounded, so that the fuse operation is accurate, and the abnormal segment can be reliably separated and the normal segment can be separated. There is no undesired separation. Therefore, it is possible to provide a small-sized and light-weight metallized film capacitor that is safe, has little capacity reduction during use, withstands high voltage, and is inexpensive.

[Brief description of the drawings]

FIG. 1 shows a metallized film of one embodiment of the present invention;
(A) is a partial plan view, and (b) is a partial enlarged view.

FIG. 2 shows a metallized film according to another embodiment of the present invention;
(A) is a partial plan view, and (b) is a partial enlarged view.

FIGS. 3A and 3B show a metallized film according to still another embodiment of the present invention, wherein FIG. 3A is a plan view of a part of the metallized film, and FIG.

FIGS. 4A and 4B show a metallized film according to still another embodiment of the present invention, wherein FIG. 4A is a plan view of a part thereof, and FIG.

FIGS. 5A and 5B are cross-sectional views in the width direction of a film showing various combinations of dielectric films according to the present invention, wherein FIG. 5A shows a combination of single-sided metal vapor-deposited films, and FIG. Combination of film and two insulating films,
(C) is a combination of a double-sided metal deposition film and an insulating film.

FIG. 6 is a sectional view showing a state where the capacitor element of the present invention is housed in a container.

FIG. 7 is a graph showing a relationship between a film potential gradient and a capacitance change rate in a cumulative overvoltage test of a capacitor embodying the present invention.

8 is a diagram showing the relationship between the fuse width W ₁ and the rate of change in capacitance and tan δ in the embodiment shown in FIG. 1 of the present invention.

FIG. 9 is a diagram showing the relationship between the resistance value of the deposited film, the rate of change in capacitance, and tan δ when the fuse section width W ₁ is 1 mm in the embodiment shown in FIG. 1 of the present invention.

FIG. 10 is a diagram showing the relationship between the fuse section width W ₁ and the capacitance change rate and tan δ in the embodiment shown in FIG. 2 of the present invention.

11 is a diagram showing a relationship between a deposited film resistance, a capacitance change rate, and tan δ when a fuse portion width W ₁ is 1 mm in the embodiment shown in FIG. 2 of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Film 2 Insulation slit 3 Insulation slit 4 Insulation slit 5 Metal deposition electrode 6 Segment 7 Strip conduction path 8 Insulation margin 9 Fuse part W ₁ Fuse part width W ₂ Insulation slit width

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Noboru Nishiguchi, Nichicon Co., Ltd., 3rd floor of Uehara Bldg., 3rd floor, 191 Nakaboricho, Ichidori-Karasuma, Nakagyo-ku, Kyoto-shi, Kyoto (72) Inventor Toru Nakaji Kyoto Nichicon Co., Ltd., 3rd floor, Uehara Bldg. 3rd, 191 Nakaboricho, Nakaike-ri

Claims (7)

[Claims] 1. A metallized film having a metallized electrode on one side, or a metallized film having a metallized electrode on both sides or an insulating film, or two metallized films having a metallized electrode on one side. And two insulating films are alternately overlapped and wound, and a capacitor formed by spraying metal on both winding end surfaces and providing an electrode lead-out portion, wherein at least one of the metal-deposited electrodes is formed of the film. It is divided into a number of hexagonal segments by insulating slits in three directions other than the width direction, and the three segments having the apexes at the meeting points of the insulating slits in three directions are assembled by the metal deposition layer constituting the electrode. They are connected to each other by a fuse portion formed at a point, and the end of the insulating slit in this fuse portion is rounded, and The segment area is 25 to 90
A metallized film capacitor having a diameter of 0 mm ² . 2. Each of the segments includes three of the fuse portions.
Each of these fuse portions has one of the above segments.
Is provided in the apex portion of every individual, the width W ₂ of the insulating slits are 0.2 to 2.0 mm, the dimension W ₁ of the fuse portion is 0.2 to 2.0 mm at the narrowest portion The metallized film capacitor according to claim 1, wherein: Wherein each segment has a fuse unit by 6, the width W ₂ of the insulating slits from 0.2 to 1.75
mm, and the dimension W ₁ of the fuse portion is 0.3 mm at the narrowest portion.
2. The metallized film capacitor according to claim 1, wherein the thickness is 2 to 1.75 mm. 4. A resistance value of a metal deposition film in each segment and each fuse portion of the metal deposition electrode is 6 to 4.
2. The metallized film capacitor according to claim 1, wherein the resistance value of the metal-deposited film is 0 to 10 Ω / square, and the resistance value of the metal-deposited film at the portion connected to the electrode lead portion is 2 to 10 ohms / square. 5. A band-shaped conductive path extending in a longitudinal direction of the film is formed at a side edge portion of the metal deposition electrode connected to the electrode lead portion by a metal deposition layer constituting the electrode. The metallized film capacitor according to claim 1 or 4, wherein: 6. The metallized film capacitor according to claim 1, wherein the potential gradient of the film at the rated voltage of the capacitor is 150 to 340 V / μm. 7. The metallized film capacitor according to claim 1, wherein the capacitor is used for power, charge / discharge, or DC filter.