JPH10261541A - Capacitor and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a self-recovery performance, achieve a higher potential design as compared with before, and make compact and less expensive a capacitor, and reduce manufacturing man-hour by extending a metallization plastic film in the longer direction and forming a number of small cracks that are thin in a film width direction on a vapor deposition film. SOLUTION: When obtaining a metallization plastic film 1 such as polyethyleneterephthalate film, an aluminum vapor deposition electrode 2 is provided by applying or transferring oil to its one surface, and then zinc 3 is further vapor-deposited by masking. More specifically, aluminum is deposited on a metal deposition electrode layer and further the zinc 3 is vapor-deposited near an area containing the contact part of a metal sprayed for extracting an electrode. When combining two single-surface deposition films for winding, the metallization deposition film is extended in the longer direction with 0.2-5% expansion rate and a number of thin, and slight cracks 4 of the vapor deposition film are formed in the width direction of a film, thus performing the flame spraying of the metal sprayed for extracting electrode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION In general, energy charging / discharging capacitors used for power capacitors and electric equipment capacitors are used for impulse voltage / current generators such as flash lamp power supplies, or for the dielectric strength test between the grounds of power equipment and the like. The device has a use.
The present invention relates to a capacitor suitable for these uses and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, an insulating structure of a capacitor used in such a power supply / apparatus is constituted by a paper or a plastic film as a dielectric or a composite structure of these dielectrics. The electrodes are made of aluminum foil or metallized paper with zinc or the like deposited on paper, and these dielectrics and electrodes are wound to form capacitor elements.
One or more of these capacitor elements are assembled,
In addition, according to the required voltage and capacity, the capacitors are connected in series and in parallel to form a collective capacitor element, which is housed and sealed in an outer case to form a capacitor.

Recently, many capacitors using a metallized plastic film in which metal is deposited on a plastic film have been proposed.

[0004]

Recently, there has been an increasing demand for smaller and lighter devices and equipment using these capacitors. Most of the volume of these capacitors is occupied by a capacitor element with a dielectric and electrodes wound around, and increasing the potential gradient of the dielectric and reducing the film thickness is a major factor in reducing the size of the capacitor element. It will contribute.

In order to increase the potential gradient of the dielectric, it is conceivable to reduce the thickness of the film. However, the reliability is naturally lowered with respect to pressure resistance and life. Therefore, in order to ensure higher pressure resistance performance and longer life characteristics with a thin film, the thickness of the metallized film deposited metal film should be different between the vicinity including the contact portion with the electrode drawing metallikon and the other main electrode portions. Winding or laminating a stepped vapor deposition film provided to improve the recovery of insulation defects existing in the metallized film by self-healing (self-healing), and to further improve the potential gradient of the film. (JP-A-62-188210).

[0006] The self-healing is to recover the dielectric strength of the insulation defect by scattering the deposited film around the insulation defect by the short-circuit current at the insulation defect. If this self-healing is incomplete,
The dielectric strength of the insulation defect part becomes the dielectric strength of the entire film, and the capacitor must be designed with a minimum dielectric strength or less. If this self-healing is performed well, the dielectric strength of the film can show the original dielectric strength of the film, that is, the potential gradient of the film can be improved.

[0007] Further, in order to perform good self-recovery, the thickness of the deposited electrode film is reduced to increase the scattering property of the deposited film, or to reduce the short-circuit current flowing into the insulation defect portion, thereby reducing the self-recovery. Recovery can be better and smaller.

In order to improve the self-healing property, the vapor deposition film at the main electrode portion is made thinner than before so as to make the self-healing more complete.
In order to improve the contact property with the metal lead for electrode extraction, the thickness of the deposited film in the vicinity of the metal lead for electrode extraction is thicker than that of the main electrode portion, that is, a so-called loose-edge structure, and stepped deposition is performed. In order to perform this stepped deposition, zinc metal is generally used as a deposition metal, and aluminum is rarely used.

This is because zinc metal can form the stepped state better than aluminum in stepped evaporation in which the thickness of the metal to be deposited is changed in the film width direction. It should be noted that stepped deposition is also possible with aluminum, but when the stepped formation state is not good,
The contact property between the metallikon and the heavy edge is deteriorated, and the current resistance is reduced. In addition, even in stepped evaporation using thin zinc metal in the main electrode part, the thickness of the evaporated film is the limit in the current state, which leads to further improvement in potential gradient including management of resistance value It is difficult to seek improvement.

Further, as another example, in a metallized film capacitor in which two plastic films each having a metal film deposited on one surface thereof are combined and wound, a continuous insulating portion in the longitudinal direction is provided in the deposited metal portion, and one capacitor element is provided. To form three or more series capacitors and to provide an insulating part also in the film width direction to provide an energy storage and rapid discharge capacitor having a large number of small capacitor networks in which a plurality of capacitor parallel circuits are provided within one capacitor element. Fairness 6
No. 18153), and the stored energy of a small capacitor constituted by one continuous conductor section divided in series and parallel facing the counter electrode is 1 joule or less at a rated voltage, and There is an energy storage and rapid discharge capacitor in which the plastic film has a potential gradient of 150 kV / mm or more.

That is, the capacitor for energy storage and rapid discharge is divided into small capacitors by a continuous insulating portion which is a non-evaporated portion, so that the energy amount of one capacitor is reduced, and the self-recovery (self-recovery) generated in the capacitor is reduced. By reducing the energy flowing into the healing, the insulation recovery is improved and the pressure resistance of the metallized film is improved.

However, in order to form a continuous insulating portion which is a non-evaporated portion of the metallized film, particularly a division in the width direction, a separate process is required. By processing etc.
It is necessary to remove a necessary portion of the deposited metal. The end of the vapor deposition film at the divided part in the width direction of the vapor deposition film obtained by these processes is likely to become an insulation defect part due to the minute burrs formed when the vapor deposition film is removed, and the processing method and processing accuracy are sufficiently controlled. It is necessary and causes cost increase.

In general, improving the self-healing property of a capacitor using a metal-deposited film improves the withstand voltage performance and enables a higher potential design than before.

An object of the present invention is to provide a capacitor which has improved self-recovery performance, can be designed with a higher potential than ever before, can be small, inexpensive, and can reduce the number of manufacturing steps.

[0015]

In order to achieve this object, the present invention provides a metallized plastic film having a metallized electrode on at least one side thereof, which is wound around the metallized plastic film. This is a capacitor in which zinc is deposited in the vicinity including the contact portion with the metallikon for metallization, in which the metallized plastic film is stretched in the longitudinal direction and a number of minute cracks elongated in the width direction of the film are formed in the deposited film. .

Further, the method for manufacturing a capacitor of the present invention comprises:
In order to stretch the metallized plastic film in the longitudinal direction and to make minute cracks in the metal deposition electrode layer in the width direction, a stretching roller is provided during the winding process of the metallized plastic film, and the metal is pressed between the metal roller and the holding roller. It is characterized by being wound as a capacitor element while stretching a plasticized plastic film.

Further, in the method for manufacturing a capacitor according to the present invention, in the above-described method for manufacturing a capacitor, the structure of the capacitor element formed of a metallized film is a wound shape, the element shape is an oval shape, and the pressure for pressing into an oval shape. Is 0.5-
It is characterized by being 1.5 kg / cm ² .

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The capacitor of the present invention is characterized in that a metallized plastic film is stretched in the longitudinal direction and a large number of minute cracks elongated in the width direction of the film are formed in the deposited film. The path of the electric energy flowing into the portion becomes longer, and the concentration of the electric energy is reduced, thereby improving the self-recovery performance of the capacitor.

Further, a method of manufacturing a capacitor according to the present invention comprises:
A stretching roller is provided during the winding process of the metallized plastic film, and the metallized plastic film is wound while being stretched between a press roller facing the winding shaft to form a capacitor element. It has an effect that a minute crack of the deposited film can be stretched in the winding step.

Further, in the method for manufacturing a capacitor according to the present invention, in the above-described method for manufacturing a capacitor, the pressure for pressing into an oval shape is set to 0.5 to 1.5 kg / cm ^2, and It has the effect of stabilizing the scattering properties of the electrodes and forming minute cracks in the deposited film in which the electric energy flowing into the dielectric breakdown portion of the deposited film becomes uniform.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. (Embodiment 1) In Embodiment 1, when obtaining a metallized plastic film 1 such as a polyethylene terephthalate (PET) film, an aluminum vapor-deposited electrode 2 is provided by applying or transferring oil to one surface thereof, Thereafter, zinc 3 was further evaporated by masking.
This vapor deposition may be performed in the same vapor deposition step, or may be performed in two steps if it cannot be performed in the same vapor deposition step. In addition, sample 1 is aluminum deposition 2
R = 8 to 20 Ω / □, and the film resistance in the vicinity including the contact portion with the electrode extraction metallikon is R = 2 to 7Ω / □.
□ That is, aluminum was deposited on the metal-deposited electrode layer, and zinc 3 was deposited in the vicinity including the contact portion with the metal lead for extracting the electrode. As shown in FIGS. 1 (a) and 1 (b), when this single-sided vapor deposition film is wound in combination with two sheets, the metallized vapor deposition film is 0.2 to 5 mm in the longitudinal direction.
% Of the vapor-deposited film elongated in the width direction of the film to form minute cracks 4 in the film, and spraying a metallicon for extracting an electrode to form a capacitor element.

The size of the minute cracks 4 of the capacitor element of the sample 1 is elongated in the width direction and the long side a is 10 to 100.
μm, the short side b is 0.1 to 1 μm, and the distribution density is 100 μm.
It is 0 to 100000 (pieces / cm ² ).

The capacitor element was housed in a metal case, impregnated with insulating oil, and connected to an electrode extraction metallikon with an external electrode extraction terminal to form a capacitor.

The thickness of the metallized plastic film 1 used for the capacitor of Sample 1 was 10 μm, and the capacity of the formed capacitor was 30 μm.

(Comparative Example 1) Comparative Example 1 is a capacitor prepared by the same process as that of the first embodiment, but having no fine cracks 4 formed in the deposited film.

(Comparative Example 2) Comparative Example 2 is prepared by the same process as in Embodiment 1, except that the film resistance value of the aluminum deposition electrode 2 is R = 8 to 20Ω / □, The film resistance in the vicinity including the contact portion is also R = 8 to 20Ω /.
It is a capacitor marked with □.

(Comparative Example 3) Comparative Example 3 was prepared by the same process as that of Embodiment 1, except that the resistance value of the aluminum-deposited metal film 2 was R = 2 to 7Ω / □, and the contact with the metal lead for extracting an electrode was made. The capacitor in which the film resistance in the vicinity including the portion is also R = 2 to 7Ω / □.

(Conventional example) As a conventional example, PET film 1
When obtaining a single-sided vapor-deposited film, oil is applied or transferred to one side of the film, and the zinc-deposited electrode 3 is masked.
a was formed. At this time, the film resistance value of the zinc-deposited metal 3a was R = 8 to 20Ω / □, and the film resistance value in the vicinity including the contact portion with the electrode lead-out metallikon was R = 2 to 7Ω / □ according to the first embodiment. Was. Further, the conventional example is a capacitor in which minute cracks 4 are not formed in the film. Then, two stepped vapor deposition films were combined and wound, and a metallicon for extracting an electrode was sprayed to obtain a capacitor having a capacitor element.

When the first embodiment is compared with the two capacitor elements of the conventional example, the appearance is almost the same, but the main electrode portion is the aluminum electrode 2 in the first embodiment. In the conventional example, it is a zinc vapor deposition electrode 3a. In the vicinity including the contact portion with the metal lead for electrode extraction, the first embodiment has a two-layer vapor deposition structure in which a zinc vapor deposition electrode 3 is provided on an aluminum vapor deposition electrode 2. In the conventional example, only the zinc deposition electrode 3a is provided. In the first embodiment, minute cracks 4 in the deposited film are formed, but in Comparative Examples 1 to 3, there is no difference in surface gloss because the minute cracks 4 in the deposited film are not formed.

Next, in order to verify the effect of the capacitor of the first embodiment, a breakdown test was performed by applying a voltage to the capacitor of Sample 1, and the breakdown voltage level was evaluated. FIG. 2 is a graph in which the breakdown voltage is plotted on the vertical axis. At this time, the test conditions are normal temperature and normal humidity, and the voltage boosting speed is 100 V per minute.

As can be seen from FIG. 2, the capacitor of sample 1 has a breakdown voltage of 9 times that of the conventional capacitor.
It turns out that it exceeds 00V-1200V. Also,
It can be seen that Comparative Example 1 is lower than Sample 1 by 200 V to 300 V. Further, Comparative Example 2 shows a breakdown level almost the same as that of Comparative Example 1, but shows some variation. Further, it can be seen that Comparative Example 3 is slightly higher than the conventional example having a lower destruction level than the capacitors of Example Sample 1 and Comparative Examples 1 and 2. The capacitor element after the destruction test was disassembled and the state of the metallized plastic film 1 was confirmed.
Self-healing (self-healing) as shown in FIGS. 5A and 5B and FIGS. 5A and 5B was confirmed. And 3
(A) and (b) are conventional metallized plastic films 1
This indicates that the insulation defect portion 4 has a large shape, and in some cases, self-recovery was not well performed and the film of the layer was broken. Although self-healing is performed better by performing this stepped vapor deposition than when stepped vaporization is not performed, it is still incomplete self-recovery that damages the film and lowers the dielectric strength. Recognize. In addition, the zinc deposition electrode 3a
It can be seen that the self-healing by the evaporated film scattering portion 5 cannot recover the dielectric strength inherent to the film.

FIGS. 4 (a) and 4 (b) show the destruction of the metallized plastic film 1 of Comparative Example 1. The insulating defect 7 is smaller in shape than the conventional example, but is incomplete in the deposited film scattering portion 8. Self-healing was also observed.

FIGS. 5 (a) and 5 (b) show the destruction of the metallized plastic film 1 of the sample 1. The shape of the insulating defect 9 is much smaller than that of the conventional metallized plastic film, and is good. Scattered parts 10 and 11
, Self-recovery is performed, and there is no variation as in Comparative Example 1. Further, it can be seen that the deposited film scatters around the dielectric breakdown portion by the minute cracks 4 around the self-recovery, and the insulation is more effectively performed. Therefore, it is considered that the damage to the film is small and the dielectric strength is closer to the dielectric strength inherent to the film.

In Comparative Example 2, as in Sample 1, the self-healing shape was much smaller than that of the conventional metallized plastic film, and the self-healing was performed well. In the vicinity of the vapor deposition film including the contact portion, the vapor deposition film was scattered, the contact with the metallikon was lost, and the capacitor capacity was lost.
This is because the deposited film near the contact portion was scattered and lost due to the current at the time of self-recovery because the film resistance near the contact portion with the electrode extraction metallikon was high. As a result, it is considered that the withstand voltage performance was high, but the withstand current performance was low.

In Comparative Example 3, a large self-healing was observed almost in the same manner as in the case of the metallized plastic film 1 of the conventional example. In the case where the vapor deposition film resistance was low even in the scattering of aluminum and the effect of minute cracks, It can be seen that a sufficiently high withstand voltage performance cannot be obtained.

These results are due to the difference in the metal deposited at the main electrode part, that is, the difference in the scattering properties during self-recovery between aluminum and zinc. The film resistance of the metal deposited was R = 8-20Ω / □, According to the effect of setting the film resistance including the contact portion with the extraction metallikon to R = 2 to 7Ω / □, the difference is further increased due to the more minute crack effect.

Next, FIG. 6 shows the test results of the charge / discharge test of each capacitor. This is an evaluation of the current breakdown level. In the graph shown in FIG. 6, the vertical axis represents the capacity reduction rate (%), and the horizontal axis represents the number of charge / discharge cycles (cycles).
Is a plot of charge / discharge characteristics. The test conditions were normal temperature and normal humidity, and the applied voltage was 3000V. The charge / discharge current is 300 A peak current and 100 μS application time.
It is.

In FIG. 6, the order of the smaller capacity reduction at 10,000 cycles is the order of sample 1, comparative example 1, comparative example 3, conventional example, and comparative example 2. And
When the capacitor element was disassembled and the state of the metallized plastic film was confirmed in the same manner as in the voltage breakdown test, the capacitor of Comparative Example 2 showed good self-healing as in the voltage breakdown test. Despite the small number of the generated metallization, scattering of the evaporated film occurred in the deposited film including the contact portion with the metal lead for extracting the electrode, the contact with the metallikon was lost, and the capacitor capacity was lost. This is considered to be due to the same reason as in the voltage breakdown test.

In Comparative Example 3 and the conventional example, a large number of self-recoveries occurred. However, scattering of the deposited film as in Comparative Example 2 was small, and the capacity reduction was much smaller than in Comparative Example 2.
However, the self-healing state is not good, and its shape is large and it cannot be said that it is an ideal state. In these self-healing portions, the scattered energy of the deposited film is large, causing thermal damage to adjacent films. Among them, there were many parts where self-healing occurred due to dielectric breakdown in adjacent parts. as a result,
A large decrease in the capacity is caused by the scattering of the evaporated film in these many self-healing portions.

In Comparative Example 1, the magnitude of the self-recovery is smaller and the number of occurrences is smaller than those in Comparative Examples 2 and 3, etc. Recovery has been seen and the condition is not perfect.

However, in Sample 1, the magnitude of self-healing is clearly small, and furthermore, the deposited film scatters around the dielectric breakdown portion in a small crack 4 around the self-healing portion, thereby increasing the dielectric strength. The self-healing state was better and more desirable than those of the other comparative examples 1 to 3 and the conventional example.

Based on these results, a rated voltage of 3000
FIG. 7 shows the result of calculating the capacitor volume when a capacitor having a V of 200 A, a rated current of 200 A and a capacity of 30 μF was designed. In this sample 1, the result was 25 to 30% smaller than the other comparative examples 1 to 3 and the conventional example.

(Embodiment 2) Next, as a sample 2a of Embodiment 2, when a single-sided deposited film of the metallized plastic film 1 is obtained, oil is applied or transferred onto one side thereof, as shown in FIG. A continuous insulating layer is provided in the longitudinal direction of the aluminum vapor-deposited electrode 2 of the vapor-deposition pattern, that is, the vapor-deposited metal film of the metallized film, and seven series capacitors are formed in one capacitor element. A patterned zinc-deposited electrode 3 was formed.

Next, the metallized plastic film was
The resultant was wound in combination, and a metallicon for extracting an electrode was sprayed to obtain a capacitor element. This capacitor element was housed in a metal case, impregnated with insulating oil, and connected to a terminal for extracting an external electrode from the metallikon to obtain a capacitor. Further, as the sample 2b of the second embodiment, when the sample 2a is wound, the metallized plastic film is stretched in the longitudinal direction and a large number of minute cracks 4 are formed in the deposited film in the width direction of the film. A capacitor element was formed in the same manner as in Sample 2a.

Further, as the sample 2c of the second embodiment, as shown in FIG. 10, an oil is applied, transferred or laser-processed on the metal deposition electrode of the sample 2a to form a division margin 12 in the width direction of the deposition metal film. At least one of the metal deposition electrodes was divided into a plurality.

Using this metallized film, a capacitor of Sample 2c was formed in the same manner as in Sample 2a.

As a sample 2d of the second embodiment, as shown in FIG. 11, when the sample 2c is wound, a metallized vapor-deposited film is stretched in the longitudinal direction and a large number of minute vapor-deposited films are formed in the width direction of the film. Sample 2 forming crack 4
A capacitor element was obtained in the same manner as in a.

For comparison, a capacitor in which seven samples 1 were connected in series was prepared as sample 2c.

In each case, a capacitor having the same configuration as that of the first embodiment was used. The thickness of the metallized plastic film 1 used for these capacitors is 10 μm, the capacitor capacity is 4.3 μF, and the rated voltage is 21 μm.
000V.

FIG. 12 shows a graph in which the volumes of these capacitors were calculated and compared. Samples 2a to 2d were 15 to 30% smaller than comparative sample 2e. This is because, when the rated voltage becomes high and a multi-stage series configuration is required, it is better to provide a multi-stage series configuration within one capacitor element than to connect one straight capacitor element in multiple stages. That is, 1
When connecting the direct capacitor elements in multiple stages, extra space is generated in the lead wires and soldered portions for connection, which is disadvantageous in volume.

Next, as in the case of the sample 1, a breakdown voltage by applying a voltage to the capacitors of the samples 2a to 2e was carried out as a withstand voltage characteristic test, and the comparison characteristics of the respective breakdown voltage levels are shown in FIG. Similarly, FIG. 14 shows the capacity reduction rate (%) in the charge / discharge test of each capacitor as a current resistance characteristic.

In each of the characteristic tests, each sample showed satisfactory characteristics.
c and 2d show good characteristics. This is because the vapor-deposited metal film is divided in the width direction of the film and at least one of the metal-deposited electrodes is divided into a plurality of pieces, whereby the current flowing when self-healing occurs is suppressed, and the minute cracks 4 are formed. Therefore, it is considered that the path through which the electric energy flows into the dielectric breakdown portion is lengthened, and the magnitude of the self-recovery is further reduced by the action of relaxing the concentration of the electric energy.

(Embodiment 3) Next, as Embodiment 3, FIG. 15 shows a means for stretching a metallized plastic film in the longitudinal direction to form fine cracks in the metal deposition electrode layer in the width direction. A method for manufacturing a capacitor which is wound as a capacitor element while stretching a plasticized plastic film will be described with reference to FIG.

That is, as shown in FIG. 15, two sets of metallized plastic films derived from the film blank 13 are guided by each roller 14 and reach the winding shaft 15. The stretching roller 16 which is the last roller reaching the winding shaft 15
By making the rotation speed different from the rotation speed of the winding shaft 15, the metallized plastic film can be stretched between the pressing roller 17 and the stretching roller 16.

According to such a manufacturing method, the stretching process of the metallized plastic film is performed during the winding process, so that the number of steps can be reduced and the productivity can be improved.

By controlling the difference between the number of revolutions of the winding shaft 15 and the number of rotations of the stretching roller 16, it is possible to adjust the size of the minute cracks 4 generated.

(Embodiment 4) FIG.
6 (a) and 6 (b) are external views of a capacitor element 18 in which a capacitor element structure made of a metallized film according to the structure of the sample 1 is wound and has an oval shape, and a capacitor element 19 in a round shape. Is shown. Each capacitor element 1
Although the ratings and capacities of the capacitors 8 and 19 are the same, the capacitor element 18 having an oval shape has less dead space than the capacitor element 19 having a round shape, so that the overall size is 30%. About 40% smaller.

FIG. 17 shows the characteristics of a capacitor of Sample 1 in which the pressure at the time of pressing into an oval shape was changed as shown in FIG. 17 and the breakdown voltages were compared.

FIG. 16 shows that the breakdown voltage is stable and high between 0.5 and 1.5 kg / cm ² . 0.5kg / c
At pressures less than m ^{2, the} breakdown voltage decreases as the pressure decreases. This is presumed to be because the press pressure is weak and there is no uniformity between the film electrodes, and weak points such as wrinkles are likely to occur, so that the breakdown voltage is reduced or the dispersion is increased. At a pressure higher than 1.5 kg / cm ² , the pressing pressure is too high, causing excessive mechanical stress to the film to cause a weak point. It is considered that the scattering property deteriorated, the self-healing performance decreased, and the destruction level decreased.

From the above method of manufacturing a capacitor,
The volume occupancy in the external metal case in which the capacitor elements are assembled is improved, and the size of the capacitor can be reduced. In addition, when the pressure for pressing into an oval shape is set to 0.5 to 1.5 kg / cm ² , the metal deposited on the metal deposited film is formed. And the electric energy flowing into the dielectric breakdown portion becomes uniform, so that the self-healing performance is stabilized and the variation in the capacitor performance is reduced.

In the first to fourth embodiments, the example in which the metallized plastic film is used as the PET vapor deposition film has been described. However, the present invention is not limited to this configuration, and the vapor deposition film used may be PP or other polycarbonate. , Polystyrene, polyethylene and the like can be used alone or in combination. A capacitor element may be formed by laminating two single-sided vapor-deposited films of PP, or a capacitor element made of a metallized plastic film may be round or oval, and an outer container may be impregnated with polybutene oil (PO) and sealed. However, the same effect can be obtained.

[0062]

As described above, the capacitor of the present invention is
Since a large number of small cracks were formed in the width direction in the metallized plastic film vapor deposition film, the path for electric energy to flow into the dielectric breakdown part was lengthened, the concentration of electric energy was reduced, and self-recovery performance was improved. The self-healing of the insulation defect existing in the vapor-deposited film enables the self-healing to be smaller and better, and the dielectric strength can be recovered. An excellent effect of designing a capacitor using a metallized plastic film with respect to the gradient is exhibited.

The method of manufacturing a capacitor according to the present invention comprises:
Stretching the metallized plastic film in the longitudinal direction with a stretching roller during the winding process of the metallized plastic film,
The method is characterized by forming a large number of elongated fine cracks in a vapor-deposited film in the width direction, thereby reducing the number of manufacturing steps of the capacitor element and improving the productivity. In addition, when the structure of the capacitor element is a wound type, the element shape is an oval shape, and the pressure for pressing the oval shape is 0.5 to 1.5 kg / cm ² , the deposition electrode on the metallized vapor deposition film is formed. Since the scattering property is stable and the electric energy flowing into the dielectric breakdown portion is uniform, the self-recovery performance is stable, and an excellent effect of forming a capacitor with less variation in the performance is exhibited.

[Brief description of the drawings]

FIG. 1 (a) is an exploded perspective view of a capacitor according to Embodiment 1 of the present invention when it is wound. FIG. 1 (b) is a partially enlarged view of a metallized plastic film in a portion B in FIG. 1 (a).

FIG. 2 is a characteristic diagram comparing breakdown voltage characteristics of the capacitor.

FIG. 3 (a) is a partial perspective view of a conventional example showing a broken defect portion of a metallized plastic film, and FIG. 3 (b) is a cross-sectional view taken along line CC of FIG. 3 (a).

FIG. 4 (a) is a partial perspective view of Comparative Example 1 showing a broken defect portion of a metallized plastic film, and (b) is a sectional view taken along line BB of FIG. 4 (a).

5 (a) is a partial perspective view of Sample 1 of Embodiment 1 showing a broken defect portion of a metallized plastic film, and FIG. 5 (b) is a cross-sectional view taken along line AA of FIG. 5 (a).

FIG. 6 is a comparative characteristic diagram showing a capacity reduction rate with respect to the number of times of charge and discharge.

FIG. 7 is a graph showing a volume comparison of capacitors.

FIG. 8 is a schematic sectional view showing a vapor deposition pattern of a sample 2a of the capacitor according to the second embodiment of the present invention.

FIG. 9 is a schematic cross-sectional view showing a deposition pattern of Sample 2b of the capacitor.

FIG. 10 is a schematic perspective view showing a sample 2c of the capacitor.

FIG. 11 is a schematic perspective view showing a sample 2d of the capacitor.

FIG. 12 is a volume comparison diagram of samples 2a to 2e of the capacitor.

FIG. 13 is a breakdown voltage comparison diagram of samples 2a to 2e of the capacitor.

FIG. 14 is a comparison diagram of capacitance reduction rates of samples 2a to 2e of the capacitor.

FIG. 15 is a conceptual diagram of a winding step for carrying out the method for manufacturing a capacitor of the present invention.

FIG. 16 (a) is a perspective view illustrating a state where a wound capacitor element is pressed into an oval shape and assembled, and (b) is a perspective view illustrating a state where the wound capacitor element is assembled in a round shape.

FIG. 17 shows the pressing pressure (Kg /
cm ² )

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metallized plastic film 2 Aluminum vapor deposition electrode 3 Zinc 4 Minute crack 15 Winding shaft 16 Stretching roller 17 Holding roller

Claims (7)

[Claims] 1. A capacitor comprising a metallized plastic film having an aluminum-evaporated electrode wound on at least one side thereof, and a zinc-evaporated electrode provided near a contact portion with a metallicon for extracting an electrode. A capacitor that extends in the longitudinal direction and has numerous minute cracks formed in the width direction on the aluminum-deposited electrode. 2. The film resistance of an aluminum deposition electrode is R = 8.
２０20 Ω / □, and the film resistance of the zinc-deposited electrode in the vicinity including the contact portion with the metal lead metal for electrode extraction is R = 2 to 7 Ω / □.
2. The capacitor according to claim 1, wherein 3. The capacitor according to claim 1, wherein an insulating layer continuous in the longitudinal direction of the metallized plastic film deposition electrode is provided, and at least two or more series capacitors are formed in one capacitor element. 4. The capacitor according to claim 1, wherein at least one of the deposition electrodes is divided into a plurality in the width direction of the deposition electrode of the metallized plastic film. 5. The method according to claim 1, wherein the metallized plastic film is stretched in the longitudinal direction at a stretching ratio of 0.2 to 5% to form a large number of fine cracks in the aluminum-deposited electrode in the width direction. The capacitor as described. 6. A stretching roller is provided during a winding step of a metallized plastic film as a means for stretching the metallized plastic film in the longitudinal direction to form minute cracks in the aluminum-deposited electrode layer in the width direction. A method for manufacturing a capacitor, comprising forming a metallized plastic film by stretching a metallized plastic film between a holding roller facing a take-up shaft and winding the capacitor. 7. A capacitor element made of a metallized plastic film has a wound structure, and the pressing pressure for forming the capacitor element is 0.5 to 1.5 kg / cm ² in order to make the capacitor element oval. The method for manufacturing a capacitor according to claim 6, wherein: