JPH08102427A - Film capacitor - Google Patents

Abstract

PURPOSE: To provide a laminated film capacitor in a simple constitution so as to provide the metallicon part with the excellent contact property and the mechanical strength. CONSTITUTION: Within a film capacitor comprising alternately laminated layers comprising both surface evaporated and metallized films 31 and laminated films 30 are cut off to compose outer electrodes by metallicon processing 44 step, the heat contraction coefficient of molecular film for both surface evaporated and metallized film does not exceed 1%, in the long direction and the width direction while that of the laminated film does not exceed 1% but 7-15% in the width direction of the high molecular laminated film is applicable. Next, the laminated film is contracted by thermal aging so that the evaporated metal thin film layer in the retracted end parts (42, 43) may be metallicon processed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film capacitor as an electronic component.

[0002]

2. Description of the Related Art In recent years, electric and electronic circuits have been remarkably developed and used in various fields. However, the electronic parts constituting these electric and electronic circuits are required to have unique characteristics according to the purpose of use. There is a strong demand for miniaturization of electronic parts in order to realize miniaturization of electric products as well as reliability and safety of characteristics. The miniaturization of electronic parts has been promoted along with the progress of miniaturization of light, thin, short, and mainly in audio equipment, video equipment, and information equipment. In particular, with regard to ICs, the degree of integration has improved year by year and has greatly contributed to miniaturization.

In general, when attempting to downsize electric appliances and equipment, even if only some of the parts are downsized, the object cannot be achieved. Therefore, the parts alone are required to be small and highly safe. In particular, audio equipment, video equipment, and information equipment have been rapidly miniaturized, and resistors, coils, capacitors, etc. have been miniaturized mainly for electronic circuits.

In recent years, electronics used in the industrial field,
There has been a demand for miniaturization of electric parts as well.
Among these, there is a demand for changes in industrial film capacitors. Like other electronic components, the required characteristics of film capacitors include improved safety, downsizing of the shape, and current resistance with the use of inverters in power circuits.

Most of the film capacitors that have been proposed and supplied so far are mostly of the winding type and the laminating type. There are two winding methods, one that uses a metal foil and the other that uses a metal thin film for the counter electrode.The configuration is such that the electrode part and the polymer film that is a dielectric are wound alternately to form a capacitor element. To be done.

On the other hand, the laminated type is one in which an electrode portion such as a metal vapor deposition film and a dielectric such as a film are alternately laminated to form a capacitor element. In this laminated type, the metallikon surface that becomes the external electrode is a cut surface, so in order to secure the contactability of the metallikon, the metallikon surface is conventionally embossed or ashed to ensure the contactability of the metallikon after thermal spraying. Was.

[0007]

However, the conventionally proposed method for processing the shape of the metallikon surface has problems in the shape processing effect of the metallikon surface, the capacitor characteristics, the manufacturing cost, etc. due to the increase of the film thickness and the processing area. there were.

As described above, the winding method and the lamination method have been generally proposed for the production of film capacitors.
In the manufacturing of the winding method, a metal slitted film and a metal foil electrode, or a metallized film having a metal thin film electrode formed on it, are wound while being displaced in the width direction, and the contact of the metallikon surface by metallikon is usually performed. Was secured.

On the other hand, in the laminating method, after a laminated plate in which a laminated film and a double-sided vapor-deposited metallized film are laminated alternately, a longitudinal direction (MD direction) and a transverse direction (TD direction) of the laminated plate are adjusted according to the capacitance of the capacitor. This is a method of cutting into a capacitor to obtain a capacitor. Since this laminating method has a cutting process after laminating, the shape of the metallikon surface is flat, and even if the metallikon surface is sprayed with metallikon, the contact property between the metallikon and the internal electrode is weak, and the mechanical property between the metallikon and the film is low. There were problems such as weak strength.

The present invention is intended to solve the above-mentioned problems of the prior art, and provides a laminated type film capacitor having a simple structure and ensuring good contact property and mechanical strength in the metallikon portion. The purpose is to do.

[0011]

In order to achieve the above object, the film capacitor of the present invention does not have a vapor-deposited metal thin film layer and a double-side vapor-deposited metallized film having vapor-deposited metal thin film layers on both sides of a polymer film. JI is used for the film capacitor that cuts the laminated laminated film and the laminated film and processes the metal electrodes to form the external electrodes.
According to the test method based on SC 2318, the heat shrinkage of the polymer film for double-sided metallized film is 1% or less in the longitudinal direction (hereinafter, MD direction) and 1% or less in the width direction (hereinafter, TD direction). Yes, the heat shrinkage rate of the polymer film for laminated film is 1% or less in the MD direction and 7 to 15% in the TD direction, and the vapor deposition of the part where the laminated film shrinks due to thermal aging and the end part recedes. The metal thin film layer is subjected to metallikon treatment.

[0012]

By using a polymer film having a large heat shrinkage ratio in the TD direction for the laminated film, the TD direction dimension of the laminated film is contracted by heat aging the strip element of the capacitor obtained by the strip slit from the laminated plate. ,
It is smaller than the dimension in the TD direction of the double-sided metallized film. For this reason, unevenness is generated between the double-sided vapor-deposited metallized film and the laminated film on the metallikon surface, and the vapor-deposited metal thin film layer appears in the portion where the metal film is contracted and the ends are retracted.
When the metallikon is sprayed onto the metallikon surface, the contact area between the metallikon particles and the metal thin film layer increases, the electrical contact property becomes good, and the mechanical adhesive force of the metallikon becomes strong.

[0013]

Embodiments will be described in detail below with reference to the drawings. FIG. 1 shows a cross section in the TD direction of a capacitor element cut from a laminate according to an embodiment of the present invention.
Reference numeral 31 is a double-sided metallized film in which vapor-deposited metal thin film layers (here, Al thin film layers) are applied to both front and back surfaces of the polymer film, and one side (for example, the front surface) has a margin on the left side of the figure.
An Al thin film layer 32 having 34 is provided, and an Al thin film layer 33 having a margin 35 is provided on the other surface (for example, the back surface) on the right side of the drawing. Reference numeral 30 denotes a laminated film, which is greatly shrunk by heat aging and whose end portions recede (42 and 43 are receding amounts) to form an uneven surface with the end portions of the double-sided vapor-deposited metallized film 31. Reference numeral 44 is a metallikon sprayed on the uneven surface, and the metallikon 44 has entered the recessed portion of the laminated film 30. The metallikon 44 that has entered is in contact with the Al thin film layers 32 and 33 of the double-sided vapor-deposited metallized film 31 that appear due to the receding of the edges of the laminated film 30.

Next, the manufacturing method of this embodiment will be described. Figure 2
Films for use in capacitors are usually wrapped around a circular core, as shown in. In this embodiment, a polyethylene terephthalate (hereinafter referred to as PET) film 2 having a width of 500 mm, a length of 5000 m and a thickness of 3.3 μm is wound around a vinyl chloride core 1 having a diameter of 6 inches and a length of 550 mm. ing. The longitudinal direction of this film is called the MD direction and the width direction is called the TD direction.

FIG. 3 shows a method of manufacturing a laminated body of a laminated type film capacitor. A double-sided vapor-deposited metallized film 4 made of PET having a thickness of 3.3 μm and having a predetermined margin formed thereon is set on the unwinding shaft 3. The double-sided vapor-deposited metallized film 4 extends from the unwinding shaft 3 and travels in the A direction, reaches the laminated bobbin 10 via the free rolls 7 and 9.

On the other hand, a laminated film 6 made of PET having a thickness of 3.3 μm and having no vapor-deposited metal thin film layer is fed out from the unwinding shaft 5 by B
Traveling in the direction, and reaches the laminated bobbin 10 via the free rolls 8 and 9. The double-sided vapor-deposited metallized film 4 and the laminated film 6 are put together by a free roll 9 to form a laminated bobbin 10.
Then, the laminated bobbin 10 is rotated in the C direction to obtain the laminated body 11 including the double-sided vapor-deposited metallized film 4 and the laminated film 6.

In the present invention, the heat shrinkage of the PET film used for the double-sided vapor-deposited metallized film 4 is JI
1 in both MD and TD by the measurement method specified in SC 2318
On the other hand, as the laminated film 6, a film having a MD heat shrinkage of 1% or less and a TD heat shrinkage of 7 to 15% was used as the laminated film 6. The heat shrinkage in the TD direction is changed to 20μ in each prototype capacitor by changing the dimension between the metallikons of the capacitor element to be obtained.
This is to secure a heat shrinkage amount of m or more.

In this example, a PET film having a heat shrinkage in the MD direction of 0.6% and a heat shrinkage in the TD direction of 0.8% was used as the double-sided vapor-deposited metallized film, and the heat shrinkage in the MD direction was used as the laminated film. Rate is 0.6%, TD
A PET film having a heat shrinkage ratio of 10% in the direction was used.

FIG. 4 shows the heat pressing process.
A laminate 11 composed of the double-sided vapor-deposited metallized film 4 and the laminated film 6 wound by the laminate bobbin 10 was sandwiched between heat press plates 12 and 13 to press the laminate 11. Heat press conditions are temperature 70 ± 5 ℃, pressure F1 is 8.0
The heat press plate 13 was fixed, and pressure was applied by the heat press plate 12 at ± 1.0 Kgf / cm ² for 60 minutes.

FIG. 5 shows a method of separating the laminated body 11. After the heat pressing step, the upper and lower ends of the laminated body formed on the laminated bobbin 10 in the MD direction are rotated by the saw blades 16, 17, 18 ,.
It cuts and separates at 19 to obtain two laminated plates 20 and 21. 14,
15 is a corner part.

FIG. 6 shows the contents of the laminated plate 20. The 22 direction is the MD direction and the 23 direction is the TD direction. Further, 24 is a cutting separation surface. Normally, the margin is formed in the MD direction, but a margin may be formed in the TD direction due to the security function.

FIG. 7 shows a method of cutting out the strip elements 28 from the laminated plate 20. A strip element 28 is obtained by slitting a central portion 25 of a margin 29 in the MD direction formed on the double-sided vapor-deposited metallized film 4 constituting the laminated plate 20 with a blade 26. Reference numeral 27 denotes a slit surface with respect to the cut separation surface 24, which is a metallikon surface. The slit element 28 had a slit width of 9.6 mm, a laminated thickness of 3.2 mm, and a length of 360 mm.

FIG. 8 is a sectional view taken along the line D-D 'of the strip element 28 of FIG. 7, showing a structure in which a laminated film 30 and a double-sided vapor-deposited metallized film 31 are alternately laminated. One surface has an Al thin film layer 32 with a thickness of about 0.05 μm provided with a margin 34 on the slit surface 27 side, and the other surface has a thickness of about 0.05 μm provided with a margin 35 on the slit surface 27 'side. An Al thin film layer 33 is formed.

In FIG. 8, the space between the double-sided vapor-deposited metallized film 31 and the laminated film 30 shown by 36 is exaggerated for the purpose of explaining the embodiment of the present invention. Since the layer thickness is about 0.05 μm, the void 36 between the layers is almost zero. Therefore, the slit surface 27,
27 'is a slit surface having almost no space between the laminated film 30 and the double-sided vapor-deposited metallized film 31.

When an external electrode made of metallikon is formed on the slit surface of the cross section shown in FIG. 8, a cross sectional structure as shown in FIG. 13 is obtained. That is, the contact between the Al thin film layers 32 and 33 formed on the double-sided vapor-deposited metallized film 31, which is the internal electrode, and the metallikon 44 is only the contact between the cut sections of the Al thin film layers 32 and 33. Contact is insufficient. Further, since the layer of the metallikon 44 is formed on the slit surface having almost no space between the alignment flume 30 and the double-sided vapor-deposited metallized film 31, the bite between the film layers of the metallikon 44 is small, and the mechanical strength is extremely weak,
This characteristic is also insufficient for practical use of the capacitor. Conventionally, such a structure was used.

Therefore, in the present invention, as shown in FIG. 9, the thermal aging treatment of the strip element is performed before the metallikon treatment. In the strip element storage frame 37, the strip elements 28 and the separation plate 38 made of metal and having a thickness of 0.2 mm are alternately stacked so that the stacking direction of the strip elements 28 is vertical, and the thickness made of metal is formed on the uppermost portion. Place an upper plate 39 of 5 mm in length, and use this upper plate 39 for the element storage frame
Pressing force F2 by two press pins 40 provided on the top of 37
Pressurize with. Thermal aging treatment not shown 120 ±
Performed in a constant temperature layer of 5 ° C, the pressure is 1.0 ± 0.2K in the first stage
A pressure of gf / cm ² was applied for 30 minutes, and a pressure of 3.0 ± 0.2 Kgf / cm ² was applied for 150 minutes in the second step to pressurize the filament element 28, and heat aging treatment was performed.

FIG. 10 shows an outline of the cross section of the strip element after the heat aging treatment. The slit width dimension after the heat aging treatment with respect to the slit width dimension before the heat aging treatment is 9.6 mm, while the double-sided vapor-deposited metallized film 31 is almost unchanged, while the laminated film 30 is 0.06 to 0.
It had shrunk by 04 mm and 0.052 mm on average. Slit surface 41, 41 '
Amount of receding edge due to heat shrinkage of laminated film 30
42 and 43 are 0.024 to 0.029 mm, and due to the receding of the edges of the laminated film, a space corresponding to the thickness of the laminated film is created on the metallikon surface, which is sufficient to secure the contactability by the metallikon. It was

Since the heat shrinkage of the laminated film in the TD direction is 10%, the heat shrinkage is 9.6 × 0.1 = 0.96 mm from the slit width dimension of 9.6 mm. However, in this example, the heat shrinkage amount was the above-mentioned amount because the pressure treatment was performed by the heat press, the heat aging treatment temperature was 120 ± 5 ° C., and the pressure was applied during the heat aging treatment. It is a thing.

FIG. 11 shows the metallikon 44 after the heat aging treatment.
FIG. 12 shows the strip element 28 that has been sprayed, and FIG. 12 shows the capacitor element 45 cut from the strip element 28. The EE 'cross section of the capacitor element 45 is as shown in FIG.

In this example, in order to examine the amount of receding of the end portion due to the heat shrinkage of the laminated film with respect to the double-sided vapor-deposited metallized film, in order to examine the amount of 1.5 times the rated voltage of the capacitor to be tested at the stage of the capacitor element sprayed with metallikon. As a result of 10 times of charge / discharge test with voltage, there was almost no receding amount in the capacitor whose heat shrinkage in the TD direction of the laminated film was 2% or less, and the reduction rate of capacitance after the charge / discharge test was 92%. On the other hand, the receding amount was about 20 to 30 μm in the capacitor in which the heat shrinkage ratio of the laminated film in the TD direction was 10%, and the reduction ratio of the electrostatic capacity after the charge / discharge test was 1% or less. As a result of these tests, the receding amount for the double-sided vaporized metallized film at the end of the laminated film satisfies the effect of the present invention if it is approximately 20 μm or more, and the upper limit of the receding amount is the margin width provided in the double-sided vaporized metallized film. It was below.

Therefore, the heat shrinkage in the TD direction of the laminated film used in the present invention is determined by the capacitance, which is to be obtained by the capacitor, in the size, length, width, and height ranges of the capacitor element, particularly in the width of the opposing surface. As a result of many examinations in consideration, it was within a range where the effect of the present invention was obtained when the amount was 7 to 15%.

After the lead wire was welded to the capacitor element thus manufactured, it was packaged in a usual process to obtain a film capacitor. Rated voltage 200V, capacitance 0.33
As a result of various tests of the μF laminated type film capacitor, the performance was the same level as the film capacitor manufactured by other methods. Therefore, the film capacitor of the present invention is extremely easy to make unevenness on the metallikon surface as a laminated type, and can reduce the manufacturing cost, and satisfy the high productivity of the laminated type, the high capacitance accuracy of the capacitor element, the miniaturization, and the like. A film capacitor can be provided.

In addition to PET for the polymer film,
Polyethylene naphthalate (PEN), polyphenylene sulfide (PPS) and polypropylene (PP) films were also examined, but the same results as with PET were obtained.

Further, in describing the embodiments of the present invention, specific materials, shape dimensions, manufacturing conditions, etc. have been described, but the present invention is not limited to these.

[0035]

As described above, according to the present invention,
By using a polymer film having a large heat shrinkage ratio in the TD direction for the laminated film, the strip element of the capacitor obtained from the laminated plate by the strip slit is heat-aged to shrink the dimension of the laminated film in the TD direction. By subjecting the resulting uneven surface to a metallikon treatment, the contact area between the metallikon particles and the metal thin film surface increases, good electrical contact properties can be obtained, and the mechanical adhesion force of the metallikon can be improved. Play.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a wide and long raw material film, and a display method in the width direction and the longitudinal direction.

FIG. 3 is a diagram showing an example of a method for obtaining a laminate by laminating a double-sided vapor-deposited metallized film and a laminated film.

FIG. 4 is a diagram showing a heat pressing method for a laminate.

FIG. 5 is a diagram showing a method of taking out a laminated plate from a laminated body.

FIG. 6 is a diagram showing the contents of a laminated plate.

FIG. 7 is a diagram showing a slitting method for obtaining a strip element from a laminated plate.

FIG. 8 is a sectional view of a strip element.

FIG. 9 is a diagram showing an example of thermal aging treatment of a strip element.

FIG. 10 is a sectional view of the strip element after the thermal aging treatment.

FIG. 11 is a perspective view of a metal element treated strip element.

FIG. 12 is a diagram showing cutting out of a capacitor element from a metal-recon-processed strip element.

FIG. 13 is a cross-sectional view of a strip element that has not been subjected to thermal aging treatment and that has been subjected to metallikon treatment.

[Explanation of symbols]

4, 31 ... Double-sided vapor-deposited metallized film, 6, 30 ... Laminated film, 20 ... Laminated plate, 28 ... Strip element, 32, 33
... Al thin film layer, 34, 35 ... margin, 42, 43 ... receding amount of the end of the laminated film, 44 ... metallikon.

Claims (2)

[Claims] 1. A double-sided vapor-deposited metallized film having vapor-deposited metal thin film layers on both front and back surfaces of a polymer film, and a laminated film having no vapor-deposited metal thin film layer alternately laminated, cut and subjected to metallikon treatment to form an external electrode. In the film capacitor constituting the above, according to the test method based on JIS C 2318, the heat shrinkage of the polymer film for double-sided vapor-deposited metallized film is 1% or less in the longitudinal direction and 1% or less in the width direction. Shrinkage rate of polymer film for use in the longitudinal direction is less than 1%, width direction is 7-15%
The film capacitor, wherein the metallized film is applied to a portion of the vapor-deposited metal thin film layer in which the laminated film is contracted by heat aging and the end portion is receded by heat aging. 2. The film capacitor according to claim 1, wherein the polymer film for double-sided metallized film and the polymer film for laminated film are made of polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, or polypropylene.