JP6744486B2 - Film capacitor, concatenated capacitor, and inverter and electric vehicle using the same - Google Patents

Description

The present disclosure relates to a film capacitor, a connection type capacitor, and an inverter and an electric vehicle using the same.

The film capacitor has, for example, a dielectric film made of polypropylene resin and a metal film formed by vapor deposition on the surface of the dielectric film. The metal film is used as an electrode. With such a configuration, in the film capacitor, even when a short circuit occurs in the insulation defective portion of the dielectric film, the metal film around the defective portion is evaporated and scattered by the energy of the short circuit, and the insulation defective portion is insulated. , Has the advantage of being able to prevent dielectric breakdown of the film capacitor (self-healing property) (see, for example, Patent Document 1).

In this way, the film capacitor can prevent ignition and electric shock when the electric circuit is short-circuited. This point has attracted attention, and in recent years, the use of film capacitors has been expanded to applications such as LED (Light Emitting Diode) lighting power supply circuits, motor drives for hybrid vehicles, and inverter systems for solar power generation.

The structure of the film capacitor is classified into a wound type and a laminated type. In the laminated film capacitor, the wrinkles of the dielectric film, which are found in the wound film capacitors, and the deterioration of the insulating property due to the wrinkles are unlikely to occur. On the other hand, since a laminated film capacitor is often obtained by cutting a laminated body in which a plurality of dielectric films and metal films are laminated, it is possible to reduce the insulation deterioration of the cut surface caused by cutting the vapor-deposited metal portion. For the purpose, a method of removing the metal film at the cut portion is disclosed (see Patent Document 2).

JP-A-9-129475 JP, 2007-96158, A

The film capacitor of the present disclosure includes a main body part in which a plurality of rectangular dielectric films and metal films are alternately laminated, and external electrodes. The external electrodes are respectively provided on a pair of body end portions located at both ends of the body portion in the first direction. The rectangular dielectric film has a first end and a second end located at both ends in the first direction, and a third end located at both ends in a second direction different from the first direction, Have. The metal film includes a first metal film and a second metal film arranged between the first metal film and the third end portion, and the first metal film and the second metal film are While being spaced apart, at least a part of the first metal film is connected to the external electrode at the end portion of the main body , and the second metal film has a plurality of divided portions separated from each other.

The coupled capacitor of the present disclosure includes a plurality of film capacitors and a bus bar that connects the plurality of film capacitors, and the film capacitor includes the film capacitor described above.

The inverter of the present disclosure includes a bridge circuit configured by a switching element and a capacitance section connected to the bridge circuit, and the capacitance section includes the film capacitor.

An electric vehicle according to the present disclosure is an electric vehicle that includes a power source, an inverter connected to the power source, a motor connected to the inverter, and wheels driven by the motor, and the inverter is the inverter described above. Is.

It is a perspective view which shows typically the laminated film capacitor. FIG. 1B is a plan view of FIG. 1A. It is one of the examples of the ii-ii sectional view taken on the line of FIG. 1A. It is another example of the ii-ii sectional view taken on the line of FIG. 1A. FIG. 2B is a plan view of the metallized film of the first embodiment of FIG. 2A. It is a top view of the 1st metallized film 5a of 1st Embodiment of FIG. 2B. It is a top view of the 2nd metallized film 5a of 1st Embodiment of FIG. 2B. It is the iv-iv sectional view taken on the line of FIG. 3A. FIG. 2B is a plan view of the metallized film of the second embodiment of FIG. 2A. It is the top view which expanded the broken line part of FIG. 5A. It is a top view which shows the metallized film 5a of 2nd Embodiment of FIG. 2B. It is a top view which shows one of the modifications of a 2nd metal film. FIG. 6B is a cross-sectional view taken along the line vi-vi of FIG. 6A. It is a top view which shows one of the modifications of a 2nd metal film. It is a top view which shows one of the modifications of a 2nd metal film. It is a top view which shows one of the modifications of a 2nd metal film. It is a perspective view which shows the structure of a connection type capacitor typically. It is a schematic structure figure for explaining the composition of one embodiment of an inverter. It is a schematic structure figure showing one embodiment of an electric vehicle.

As shown in FIGS. 1A and 1B, the film capacitor A includes a film capacitor main body 3 and a pair of external electrodes 4a and 4b provided on the opposite end faces of the film capacitor main body 3 by metallikon. Hereinafter, the film capacitor body 3 may be simply referred to as the body 3. As shown in FIGS. 2A and 2B, the main body 3 has a plurality of rectangular dielectric films 1 and metal films 2 alternately stacked.

In the main body 3 shown in FIG. 2A, a metallized film 5a having a metal film 2a on one surface of a dielectric film 1a and a metallized film 5b having a metal film 2b on one surface of a dielectric film 1b are alternately laminated. Has been done. The metal film 2a is electrically connected to the external electrode 4a at one body end portion 3a of the body portion 3. The metal film 2b is electrically connected to the external electrode 4b at the other body end 3b of the body 3. The main body portion 3 has main body end portions 3a and 3b, and a main body end surface 3c on which the external electrode 4 is not provided.

In FIG. 1A, on the surfaces of the dielectric films 1a and 1b and the metal films 2a and 2b, the direction in which the external electrodes are arranged is defined as a first direction x, and the second direction y is shown as a direction orthogonal to the first direction x. There is. The z direction is the thickness direction of the dielectric films 1a and 1b and the metal films 2a and 2b, in other words, the stacking direction.

The metallized film 5a is formed by forming the metal film 2a on one surface of the dielectric film 1a. The metallized film 5b is formed by forming the metal film 2b on one surface of the dielectric film 1b. As shown in FIG. 2A, these metallized films 5a and 5b are laminated with a slight deviation in the width direction, that is, the first direction x. That is, the main body portion 3 has a shift portion S at which the metallized films 5a and 5b do not overlap each other at the main body end portions 3a and 3b. The width of the shifted portion S is referred to as a shift amount s.

Thus, in the film capacitor A, the metallized film 5a composed of the dielectric film 1a and the metal film 2a and the metallized film 5b composed of the dielectric film 1b and the metal film 2b are shown in FIG. 2A. Are stacked so that The main body part 3 may have a cover film on the outer side where the metallized film 5a and the metallized film 5b are laminated.

The metal films 2a and 2b are electrically connected to the external electrodes 4a and 4b at different body end portions 3a and 3b located at both ends of the body portion 3 in the first direction x.

In order to explain the features common to the metallized films 5a and 5b, hereinafter, for example, as shown in FIG. 3A, the symbols a and b may be omitted. In the cross-sectional view, the thickness direction z of the film is shown in an enlarged manner for ease of explanation.

The dielectric film 1a has a first end 1c located on one side of the first direction x, a second end 1d located on the other side, and a third end 1e located on both ends in the second direction y. doing. A so-called insulating margin portion 6 (6a, 6b) in which the metal film 2 is not formed and the dielectric film 1 is exposed is provided near the second end portion 1d. The insulation margin portion 6 may be simply referred to as the margin portion 6.

When there is a potential difference between the metal film 2a and the metal film 2b, a capacitance is generated in the effective area 7 where the metal film 2a and the metal film 2b are overlapped with each other with the dielectric film 1 interposed therebetween.

<Series connection type>
In the main body 3 shown in FIG. 2B, the metallized film 5a having the metal film 2a1 and the metal film 2a2 on the first surface 1ac of the dielectric film 1a and the metal film 2b on the second surface 1bc of the dielectric film 1b are provided. The metallized films 5b are alternately laminated. The metal film 2a1 is electrically connected to the external electrode 4a at the first end 3a of the main body 3. The metal film 2a2 is electrically connected to the external electrode 4b at the second end 3b of the main body 3. The metal film 2b is not electrically connected to either the external electrode 4a or the external electrode 4b. The film capacitor A having such a structure is called a series connection type film capacitor.

FIG. 2B is a cross-sectional view taken along the line ii-ii in FIG. 1 in the case of the serial connection type film capacitor A. In FIG. 2B, the width direction of the dielectric film 1a, the dielectric film 1b, the metal film 2a1, the metal film 2a2, and the metal film 2b is the first direction x, the length direction is the second direction y, and the thickness direction is the third direction. z.

The dielectric film 1a has a first end 1ac located on one side in the first direction x, a second end 1ad located on the other side, and third ends 1ae located at both ends in the second direction y. doing. The dielectric film 1b has a first end 1bc located on one side of the first direction x, a second end 1bd located on the other side, and a third end 1be located on both ends in the second direction y. doing.

The metallized film 5a is formed by forming the metal film 2a1 and the metal film 2a2 on one surface of the dielectric film 1a. The metallized film 5a has a so-called insulating margin portion 6a in which a metal film is not formed in the central portion in the first direction x, that is, a portion where the dielectric film 1a is exposed continuously exists in the second direction y. Have

The metallized film 5b is a metal film 2b formed on one surface of the dielectric film 1b. In the metallized film 5b, a metal film is not formed in the vicinity of the first end 1bc and the second end 1bd, that is, the exposed portion of the dielectric film 1b continuously exists in the second direction y, It has a so-called insulation margin portion 6b. The width of the dielectric film 1b is slightly smaller than that of the dielectric film 1a.

As shown in FIG. 2B, these metallized films 5a and 5b are laminated with the metallized film 5a slightly protruding on both sides in the first direction x. Since the width of the dielectric film 1b is slightly smaller than that of the dielectric film 1a, the main body portion 3 has a shift portion S at which the metallized films 5a and 5b do not overlap each other at the main body end portions 3a and 3b.

When there is a potential difference between the metal film 2a1 and the metal film 2b, a capacitance is generated in the effective area 7a where the metal film 2a1 and the metal film 2b overlap with each other with the dielectric film 1a or 1b interposed therebetween. When there is a potential difference between the metal film 2a2 and the metal film 2b, a capacitance is generated in the effective area 7b where the metal film 2a2 and the metal film 2b overlap with each other with the dielectric film 1a or 1b interposed therebetween. The first capacitance section C1 having the effective area 7a and the second capacitance section C2 having the effective area 7b are connected in series.

The features applicable to both film capacitors A of FIGS. 2A and 2B will be described below unless otherwise specified.

The thickness of the dielectric film 1 may be, for example, 5 μm or less. The dielectric film 1 having a thickness of 0.5 to 4 μm may be used.

The metal film 2 (2a, 2b) may have a heavy edge structure in the vicinity of the connection portion with the external electrode 4 (4a, 4b). The heavy edge structure is a structure in which the resistance of the metal film 2 near the connection portion with the external electrode 4 is lower than the resistance of the effective region 7 where the metal films 2a and 2b overlap each other. The metal film 2 near the connection portion with the high-resistance external electrode 4 may be referred to as a heavy edge portion. In other words, the heavy edge structure refers to a structure in which the thickness of the metal film 2 in the heavy edge portion is thicker than the thickness of the metal film 2 in the effective region 7. It should be noted that the metal film 2 having a self-healing property capable of being evaporated and scattered by the energy of the short circuit is provided with a metal film 2 having a larger thickness than the metal film 2 regardless of whether it is located in the effective region 7 or not. Sometimes called a department.

The thickness of the metal film 2 in the effective region 7 may be, for example, 20 nm or less, particularly 5 to 15 nm. When the metal film 2 has such a thickness, the sheet resistance (sheet resistance) becomes 18 to 50 Ω/□, and the self-healing property can be exhibited. The thickness of the first metal film 2c and the thickness of the second metal film 2d may be the same. One of the metal film 2a and the metal film 2b may have a thickness of 20 nm or less and the other may have a heavy edge portion. Further, the thickness of the metal film 2 in the vicinity of the connection portion with the external electrode 4 (heavy edge portion) may be 2 to 4 times that of the effective region 7, that is, 10 to 80 nm.

<First Embodiment>
The first embodiment is one of the embodiments of the present disclosure. In the first embodiment, the metal film 2 is formed by the first metal film 2c (2a1c, 2a2c and 2bc) and the second metal film 2d (2a1d, 2a2d and 2bd) as shown in FIGS. 3A, 3B and 3C. Composed. The first metal film 2c is separated from the third end 1e. The second metal film 2d is arranged between the first metal film 2c and the third end 1e.

The second metal film 2d is adjacent to the first metal film 2c and extends in a strip shape in the first direction x, and is separated from the first metal film 2c. There is a first groove 8 extending in the first direction x between the first metal film 2c and the second metal film 2d. As shown in FIG. 4, there is no metal film on the bottom of the first groove 8, and the first metal film 2 c and the second metal film 2 d are separated by the first groove 8. The first metal film 2c and the second metal film 2d may be separated from each other, and the first metal film 2c and the second metal film 2d are separated from each other by the first groove extending in the first direction x. It does not have to be 8.

Thus, in the first embodiment, the metal film 2 is composed of the first metal film 2c and the second metal film 2d. In the first embodiment, the second metal film 2d exists between the dielectric films 1a and 1b near the body end surface 3c. Therefore, it becomes difficult for the dielectric films 1a and 1b to adhere to each other near the body end surface 3c. As a result, even if a short circuit occurs in the insulation defect portion and the metal film 2 evaporates and scatters to generate gas, the gas can effectively escape from the vicinity of the end face 3c of the main body. As described above, in the first embodiment, the escape property of gas generated by evaporation and scattering of the metal film 2 is improved, and the self-recovery property of the film capacitor A can be improved.

The end of the second metal film 2d in the second direction y may be located at the third end 1e of the dielectric film 1. Since the end of the second metal film 2d in the second direction y is located at the third end 1e, that is, facing the body end face 3c, the dielectric films 1a and 1b are separated from each other near the body end face 3c. It becomes more difficult to adhere. As a result, the gas escape property is further improved, and the self-healing property of the film capacitor A can be further enhanced.

Since the adhesive force between the dielectric film 1 and the metal film 2 is relatively small compared to the adhesive force when the dielectric films 1 are in direct contact with each other, the gas is passed through between the dielectric film 1 and the metal film 2 for comparison. It becomes easy to miss the target. In this case, at least a part of the end of the second metal film 2d in the second direction y may be located at the third end 1e. Since at least a part of the end portion of the second metal film 2d in the second direction y is located at the third end portion 1e, that is, at the body end surface 3c, a path for gas to escape through the body end surface 3c is secured. The ease of removal is improved.

In the first embodiment, the second metal film 2d may be connected to the external electrode at the body end 3a or 3b.

In the first embodiment, as shown in FIGS. 3A to 3C and FIG. 4, when the distance between the third end 1e in the second direction y and the first portion 2c forming the effective region is W1, W1 may be in the range of 3 to 10 mm, particularly 2 to 5 mm. By setting W1 in the range of 3 to 10 mm, and particularly 2 to 5 mm, it is possible to obtain the film capacitor A which has an electrostatic capacity and is excellent in the self-recovery function. The range of W1 described above can be applied to other embodiments described below.

<Second Embodiment>
As shown in FIGS. 5A and 5B, the first metal film 2c is located at either the first end 1c or the second end 1d of the dielectric film 1 and extends toward the third end 1e. You may have the extending part 2e which extends. FIG. 5B is an enlarged plan view of the broken line portion of FIG. 5A. When the first metal film 2c has the extension 2e in the vicinity of the first end 1c, the area of the connecting portion between the first metal film 2c and the external electrode 4 is increased, and the resistance of the connecting portion can be reduced. As shown in FIG. 5C, the extension 2e may be located near the second end 1d.

For example, in the film capacitor A shown in FIG. 2A, in the vicinity of the first end 1ac of the dielectric film 1a, with the metallized film 5a and the metallized film 5b laminated, the dielectric film 1a is a dielectric film. It refers to a portion that overlaps with the margin portion 6b of the film 1b. That is, the extension 2e is provided in the third end 1e near the first end 1ac because the metal film 2ac electrically connected to the external electrode 4a at the main body end 3a where the first end 1ac is located. Only. The vicinity of the first end portion 1bc of the dielectric film 1b is a portion where the dielectric film 1b overlaps the margin portion 6a of the dielectric film 1a in a state where the metallized film 5a and the metallized film 5b are laminated. Refers to. That is, the extension 2e is provided at the third end 1e near the first end 1bc because the metal film 2bc electrically connected to the external electrode 4b at the body end 3b where the first end 1bc is located. Only. Note that in FIG. 5A, reference numerals a and b are omitted in order to explain the features common to the metallized films 5a and 5b of FIG. 2A.

The vicinity of the first end portions 1ac and 1bc may further include a shift portion S where the metallized film 5a and the metallized film 5b do not overlap each other.

In the case of the serial connection type film capacitor A shown in FIG. 2B, the vicinity of the first end 1ac and the vicinity of the second end 1ad of the dielectric film 1a means, in the present disclosure, the metallized film 5a and the metallized film 5b. Is a portion where the dielectric film 1a overlaps the margin portion 6b of the dielectric film 1b in the state where the and are laminated. That is, as shown in FIG. 5C, at the third end 1e near the first end 1ac, the metal film 2a1c electrically connected to the external electrode 4a is formed at the body end 3a where the first end 1ac is located. At the third end portion 1e having the extending portion 2e near the second end portion 1ad, the metal film 2a2c electrically connected to the external electrode 4b is extended at the body end portion 3b where the second end portion 1ad is located. It has a protrusion 2e. The metal film 2bc is not connected to any of the external electrodes 4a and 4b and does not have the extending portion 2e.

The vicinity of the first end 1ac and the vicinity of the second end 1ad may further include a shift portion S in which the metallized film 5a and the metallized film 5b do not overlap.

Hereinafter, features common to FIGS. 2A and 2B will be described. When the first metal film 2c has the extension 2e, the second metal film 2d is provided as shown in FIG. That is, the first groove 8 extends from the margin portion 6 in the first direction x and extends toward the third end 1e toward the third end 1e in the vicinity of the first end 1c or the second end 1d. ing. The first groove 8 separates the first metal film 2c and the second metal film 2d from each other.

In the case of FIG. 2A, the metal film 2a is electrically insulated from the external electrode 4b by the margin portion 6a, and the metal film 2b is electrically insulated from the external electrode 4a by the margin portion 6b. In the case of FIG. 2B, the metal film 2a1 is electrically insulated from the external electrode 4b by the margin portion 6a, and the metal film 2a2 is electrically insulated from the external electrode 4a by the margin portion 6a. The metal film 2b is electrically insulated from both the external electrodes 4a and 4b by the margin portion 6b. Therefore, in the second embodiment, the second metal film 2d is not connected to the external electrode 4 in both cases of FIG. 2A and FIG. 2B. Therefore, even if the second metal films 2d located in different layers come into contact with each other on the body end surface 3c of the body portion 3 by cutting, the insulation deterioration of the film capacitor A itself is reduced.

As shown in FIGS. 5A and 5B, the width of the margin portion 6 is t1, the distance between the first end 1c and the portion of the extension 2e closest to the second end 1d is t2, and the first groove The width of the third end portion 1e of 8 is t3. In other words, the extending portion 2e is housed in a portion whose distance from the first end portion 1c is t2 or less. The width t1 of the margin portion 6 may be, for example, 1.5 mm or more and 3.0 mm or less. The shift amount s of the shift portion S may be, for example, 0.2 mm or more and 1.0 mm or less. For example, t3 may be 0.15 mm or more. For t2, for example, the sum of t2 and t3 may be equal to or less than the sum of t1 and s, that is, (t2+t3)≦(t1+s). By setting (t2+t3)≦(t1+s), it is possible to further reduce the insulation deterioration of the film capacitor A itself.

Specifically, t2 may be, for example, 4.0 mm or less, further 2.0 mm or less, and particularly 1.8 mm or less. Further, t2 may be, for example, 0.05 mm or more. In the film capacitor A having the margin portion 6 having the general width t1 and the general shift width s, when t2 is set in such a range, the insulation deterioration of the film capacitor A itself can be further reduced. In addition, the above-mentioned relationship shows the relationship between t1, t2, t3 and s located at the body end 3a, and also shows the relationship between t1, t2, t3 and s located at the body end 3b. ..

Hereinafter, a modified example of the second metal film 2d will be described. These modified examples can be applied to both the first embodiment and the second embodiment.

The second metal film 2d may have a plurality of divided parts 2di which are separated from each other. 6A and 7A to 7C each correspond to an enlarged plan view of the broken line portion in FIGS. 3A to 3C. As shown in FIG. 6A, the second groove 9 may extend in the first direction x and divide the second metal film 2d into a plurality of division parts 2di. 6B is a cross-sectional view taken along the line vi-vi of FIG. 6A. Further, as shown in FIG. 7A, the second metal film 2d may be composed of a plurality of divided portions 2di separated from each other by the third groove 10 extending in the second direction y. The third groove 10 may be connected to the first groove 8. The second groove 9 and the third groove 10 are voids that separate the plurality of divided portions 2di from each other. The second groove 9 and the third groove 10 may be arranged independently, or both may be arranged simultaneously as shown in FIG. 7A.

As described above, when the second groove 9 and/or the third groove 10 are present in addition to the first groove 8, the gas can escape to the outside through the second groove 9 and/or the third groove 10. Further, the gas releasing property is further improved.

In the first embodiment, the third groove 10 may have a role of separating at least a part of the divided portion 2di of the second metal film 2d from the external electrode 4. In this case, even if the divided portions 2di which are not connected to the external electrode 4 and are located in different layers come into contact with each other at the body end surface 3c of the body portion 3, the insulation deterioration of the film capacitor A itself is reduced.

Instead of the second groove 9 extending in the first direction x and the third groove 10 extending in the second direction y, as shown in FIG. 7B, an angle is formed with respect to the first direction x and the second direction y. The second groove 11d may divide the second metal film 2d into a plurality of divided portions 2di. The fourth groove 11 is composed of two kinds of grooves extending in at least two directions different from each other, and the two kinds of grooves may intersect with each other. At this time, the first groove 8 may extend linearly in the first direction x, but as shown in FIG. 7B, as with the fourth groove 11, in the two different directions. The extending groove may be connected to form the first groove 8. In this case, the region in which the first groove 8 is arranged may extend in the first direction x. In FIG. 7B, it may be said that the first groove 8 is a portion located closest to the first metal film 2 c side of the fourth groove 11. At this time, W1 is the minimum value of the distance between the third end portion 1e in the second direction y and the first portion 2c forming the effective region 7.

W2 shown in FIGS. 6A, 6B, 7A and 7B is the width of the first groove 8. P1 shown in FIGS. 6A, 6B and 7A is the interval (pitch) between the plurality of second grooves 9, and P2 shown in FIG. 7A is the interval (pitch) between the plurality of third grooves 10. P3 shown in FIG. 7B is an interval (pitch) between the fourth grooves 11.

The width W2 of the first groove 8 may be in the range of 0.01 to 0.30 mm. W2 may in particular be between 0.10 and 0.30 mm. By setting the width W2 of the first groove 8 to 0.01 to 0.30 mm, particularly 0.10 to 0.30 mm, it is possible to suppress the discharge between the first metal film 2c and the second metal film 2d. It is possible to secure the gas release property.

The widths of the second groove 9, the third groove 10, and the fourth groove 11 are not particularly limited, but are, for example, 0.01 to 0.30 mm, which is the same as the width W2 of the first groove 8, particularly 0. The range may be from 10 to 0.30 mm.

The interval P1 between the second grooves 9 and the interval P2 between the third grooves 10 may be the same or different. The intervals P3 of the fourth grooves 11 may all be the same, or the fourth grooves 11 extending in different directions may be different from each other. Further, the intervals P3 of the fourth grooves 11 may all be different.

The bottoms of the second groove 9, the third groove 10 and the fourth groove 11 may have no metal film, that is, the dielectric film 1 may be exposed, but the first metal film 2c and the second metal film may be exposed. It may be configured by the metal film 2 having a thickness smaller than 2d. That is, the z-direction depths of the second groove 9, the third groove 10, and the fourth groove 11 may be smaller than the z-direction thickness of the second metal film 2d.

The second metal film 2d may be composed of the divided portions 2di divided by the first groove 8, the second groove 9, the third groove 10, and the fourth groove 11 as described above. As shown in FIG. 7C, it may be composed of divided portions 2di arranged in a stepping stone shape. When the divided parts 2di are arranged in a stepping stone shape, the ratio of the area occupied by the divided parts 2di may be, for example, 25 to 50%.

6A, 6B, and 7A to 7C, the division portion 2di is formed into a strip shape or a rectangular shape, but the shape is not limited to this, and division of a triangular shape, a polygonal shape, a circular shape, an elliptical shape, or an irregular shape is performed. It may be part 2di.

In addition, in the film capacitor A, both the metal films 2a and 2b may have the structure as described above.

The film capacitor A as described above has a high insulating property, has a good gas releasing property of the generated gas even if a partial dielectric breakdown occurs, and becomes a film capacitor having an excellent self-recovery function.

Examples of the insulating resin material used for the dielectric film 1 include polypropylene (PP), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyethylene naphthalate (PEN), polyarylate (PAR), and polyphenylene ether (PPE). ), polyetherimide (PEI), and cycloolefin polymer (COP). In particular, cycloolefin polymer (COP) and polyarylate (PAR) have high dielectric breakdown voltage.

Further, cycloolefin polymer (COP) and polyarylate (PAR) have high adhesiveness between films when formed into a film, and gas tends to be difficult to evaporate, but the second metal film 2d as described above is provided. As a result, a large effect of improving self-healing property can be obtained.

The dielectric film 1 is obtained by, for example, molding a resin solution in which an insulating resin is dissolved in a solvent into a sheet shape on the surface of a base material made of polyethylene terephthalate (PET), and drying it to volatilize the solvent. To be The forming method may be appropriately selected from known film forming methods such as a doctor blade method, a die coater method and a knife coater method. Examples of the solvent used for molding include methanol, isopropanol, n-butanol, ethylene glycol, ethylene glycol monopropyl ether, methyl ethyl ketone, methyl isobutyl ketone, xylene, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, dimethylacetamide, cyclohexane. Alternatively, an organic solvent containing a mixture of two or more selected from these may be used. Alternatively, a resin film produced by the melt extrusion method may be stretched.

The dielectric film 1 may be composed only of the above-mentioned insulating resin, but may contain other materials. Examples of the constituents other than the resin included in the dielectric film 1 include the above-mentioned organic solvent and inorganic filler. As the inorganic filler, for example, inorganic oxides such as alumina, titanium oxide, and silicon dioxide, inorganic nitrides such as silicon nitride, and glass can be used. In particular, when a material having a high relative permittivity such as a complex oxide having a perovskite structure is used as the inorganic filler, the relative permittivity of the entire dielectric film 1 is improved and the film capacitor can be downsized. Further, in order to improve the compatibility between the inorganic filler and the resin, the inorganic filler may be subjected to a surface treatment such as a silane coupling treatment or a titanate coupling treatment.

When such an inorganic filler is used for the dielectric film 1, the inorganic filler is used while maintaining the flexibility of the resin by forming a composite film containing less than 50% by mass of the inorganic filler and 50% by mass or more of the resin. It is possible to obtain the effect of improving the relative dielectric constant. The size (average particle size) of the inorganic filler may be 4 to 1000 nm.

On one surface of the dielectric film 1, one of the ends in the first direction x in the structure shown in FIG. 2A, and both of the ends in the first direction x in the structure shown in FIG. 2B or the central part in the first direction x. After masking, a metal component such as aluminum (Al) is vapor-deposited to form the metal film 2, and the metallized film 5 is obtained. At this time, the masked portion becomes the margin portion 6.

In the case of forming a heavy edge structure, a portion other than the portion forming the heavy edge of the metallized film 5 described above is masked, and, for example, zinc (Zn) is further vapor-deposited on the portion without the mask of the vapor-deposited metal component. To form. At this time, the thickness of the film deposited as a heavy edge is 1 to 3 times the thickness of the deposited metal component.

A pattern is formed on the metal film 2 as needed. For patterning the metal film 2, a laser marker machine or a laser trimmer machine capable of skipping the metal vapor deposition film is used. As the laser, any one of a green laser, a YAG laser and a CO ₂ laser may be used.

<Method of manufacturing film capacitor>
The laminated film capacitor A according to the present disclosure may be manufactured as follows. After cutting the metallized film 5 (5a, 5b) having the metal film 2 (2a, 2b) on one surface into a desired shape, a plurality of layers are laminated to obtain a laminated body. At this time, in the structure shown in FIG. 2A, the metallized films 5a and 5b are alternately laminated so that the margin portions 6a and 6b are located at different end portions in the first direction x. Further, the metallized films 5a and 5b are overlapped with each other with a slight deviation in the first direction x, as shown in FIG. 2A. In the case of the structure shown in FIG. 2B, the metallized film 5a has a margin 6a at the center in the first direction x, and the width in the first direction x is slightly smaller than that, and the margin portions 6b are provided at both ends in the first direction x. The metallized films 5b are alternately laminated as shown in FIG. 2B.

The individual body part 3 is obtained by cutting the obtained laminated body. At this time, the surface in the vicinity of the portion to be cut is irradiated with a laser in advance to form the first groove 8 extending in the first direction x. The laser irradiation direction is the z direction, that is, the stacking direction.

Since the dielectric film 1 is transparent and allows the laser to pass therethrough, the metal film 2 of the layer irradiated with the laser is removed, so that the metal film 2 of the next layer is irradiated with the laser. Therefore, by irradiating the surface of the laminated body with a laser, the first grooves 8 can be formed at all the same positions of the laminated metallized film 5.

By cutting the laminated body along the formed first groove 8 in the vicinity thereof, the main body 3 having the cut surface as the third end 1e is obtained. Two first grooves 8 are formed in the laminated body so as to sandwich the cut portion, and the laminated body is cut between the two first grooves 8. As a result, the main body 3 having the first metal film 2c and the second metal film 2d arranged between the first metal film 2c and the third end 1e is obtained.

The film capacitor A is obtained by forming metallikon electrodes on both end surfaces of the obtained main body portion 3 in the first direction x to form the external electrodes 4. For forming the external electrode 4, for example, metal spraying, sputtering, plating, etc. are suitable.

Next, if necessary, the surface of the main body 3 having the external electrodes 4 formed thereon may be covered with an exterior member (not shown).

Examples of the material of the metal film 2 include metals such as aluminum (Al) and zinc (Zn) and alloys.

Further, as the material of the metallikon electrode, at least one metal material selected from zinc, aluminum, copper and solder can be mentioned.

The first groove 8 can also be formed by masking the position of the first groove 8 when depositing a metal component on the dielectric film 1. In the case where the second groove 9, the third groove 10, the fourth groove 11 and the like are formed in addition to the first groove 8 and the plurality of divided portions 2di are formed in the second metal film 2d, before the lamination, The first groove 8 to the fourth groove 11 may be formed by irradiating the metal film 2 of the metallized film 5 with laser or irradiating the surface of the laminate with laser.

<Connected capacitor>
FIG. 8 is a perspective view schematically showing one of the embodiments of the linked capacitor. In FIG. 8, the case and the molding resin are omitted for clarity of the configuration. In the connection type capacitor C, a plurality of film capacitors are connected in parallel by a pair of bus bars 21 and 23. The bus bars 21 and 23 have terminal portions 21a and 23a for external connection and lead-out terminal portions 21b and 23b connected to the external electrodes 4a and 4b of the film capacitor A, respectively.

When the linked capacitor C includes the film capacitor A described above, the linked capacitor C having excellent self-healing property can be obtained.

In the connection type capacitor C, a plurality of film capacitors, for example, four film capacitors are arranged side by side, and the bus bars 21 and 23 are attached to the external electrodes 4a and 4b respectively formed on both ends of the main body portion 3 with a bonding material. can get.

It should be noted that the film capacitor A and the connection type capacitor C can be made into a resin mold type (case mold type) capacitor by housing them in a case and then filling a void in the case with a resin.

<Inverter>
FIG. 9 is a schematic configuration diagram for explaining one of the embodiments of the inverter. FIG. 9 shows an example of an inverter D that produces alternating current from direct current. As shown in FIG. 9, the inverter D of the present embodiment includes a bridge circuit 31 including a switching element (for example, an IGBT (Insulated gate Bipolar Transistor)) and a diode, and an input of the bridge circuit 31 for voltage stabilization. And a capacitor 33 arranged between the terminals. The inverter D includes the film capacitor A described above as the capacitance section 33.

The inverter D is connected to the booster circuit 35 that boosts the voltage of the DC power supply. On the other hand, the bridge circuit 31 is connected to a motor generator (motor M) serving as a drive source.

<Electric vehicle>
FIG. 10 is a schematic configuration diagram of an electric vehicle. FIG. 10 shows a hybrid vehicle (HEV) as an example of the embodiment.

The electric vehicle E includes a driving motor 41, an engine 43, a transmission 45, an inverter 47, a power supply (battery) 49, a front wheel 51a and a rear wheel 51b.

The electric vehicle E has outputs of the motor 41, the engine 43, or both as drive sources. The output of the drive source is transmitted to the pair of left and right front wheels 51a via the transmission 45. The power source 49 is connected to the inverter 47, and the inverter 47 is connected to the motor 41.

Further, the electric vehicle E shown in FIG. 10 includes a vehicle ECU 53 and an engine ECU 57. The vehicle ECU 53 performs overall control of the electric vehicle E as a whole. The engine ECU 57 controls the rotation speed of the engine 43 and drives the electric vehicle E. The electric vehicle E further includes driving devices such as an ignition key 55 operated by a driver, an accelerator pedal (not shown), and a brake. A drive signal corresponding to the operation of the driving device by the driver or the like is input to the vehicle ECU 53. Based on the drive signal, vehicle ECU 53 outputs an instruction signal to engine ECU 57, power supply 49, and inverter 47 as a load. The engine ECU 57 controls the rotation speed of the engine 43 in response to the instruction signal and drives the electric vehicle E.

As the inverter 47 of the electric vehicle E, the inverter D, that is, the inverter D to which the film capacitor A or the connection type capacitor C described above is applied as the capacitance section 33 is used. In such an electric vehicle E, since the film capacitor A has excellent self-healing property, the electrostatic capacity can be maintained for a long period of time and the switching noise generated in the inverter 47 etc. can be reduced for a long period of time. it can.

The inverter D of the present embodiment can be applied not only to the above hybrid vehicle (HEV) but also to various electric power conversion application products such as an electric vehicle (EV), a fuel cell vehicle, an electric bicycle, a generator, and a solar cell. ..

Using ZEONOR (registered trademark) (manufactured by Zeon Corporation), which is a cyclic cycloolefin resin, a dielectric film having an average thickness of 3 μm was produced. ZEONOR (registered trademark) (manufactured by Zeon Corporation) was dissolved in toluene and applied on a polyethylene terephthalate (PET) base material using a coater to form a sheet. After molding, heat treatment was performed at 130° C. to remove toluene to obtain a dielectric film.

After peeling the obtained dielectric film from the base material and slitting it into a width of 130 mm, a 97 mm wide Al metal film was vacuum-deposited by using a metal mask as a metal film on one main surface of the dielectric film. Formed.

Then, a pattern was formed on the metal film using a green laser marker. The laser irradiation conditions were an output of 4 W, a frequency of 140 kHz, and a scan speed of 4 m/sec.

The metallized film having a width of 130 mm was further slitted to obtain a metallized film having a width of 50 mm having an insulating margin portion of 1.5 mm (metal film non-formation portion where the dielectric film was exposed).

The metallized films were laminated so that the metal films face each other with the dielectric film interposed therebetween, to prepare a laminate. Note that the metallized films were laminated such that the insulating margin portions were alternately arranged on the different sides in the first direction x. Further, as shown in FIG. 2A, the metallized films were laminated with each layer being shifted by 0.5 mm in the first direction x. The number of layers was 100.

The obtained laminate was irradiated with a laser at a predetermined portion using a green laser marker to form a groove as shown in Table 1 on the metal film 2. This laminated body was cut along the first groove formed by laser irradiation to obtain a main body.

An alloy of zinc and tin was sprayed on the end faces of the obtained main body portion facing each other in the first direction x to form a metallikon electrode as an external electrode to obtain a film capacitor.

The capacitance, withstand voltage, and insulation resistance before and after the withstand voltage test of the produced film capacitor were measured. The capacitance was measured using an LCR meter under the conditions of AC1V and 1 kHz. The insulation resistance and the withstand voltage were measured using an insulation resistance meter. The withstand voltage was a voltage when the leak current reached 0.01 A when a step-up test in which a DC voltage was applied to the film capacitor at a step-up rate of 0 V to 10 V per second using an insulation resistance tester.

Sample No. The samples Nos. 1 to 20 had a small decrease in insulation resistance before and after the withstand voltage test and were excellent in self-healing property. On the other hand, the sample in which the second metal film was not formed, that is, the sample No. in which the metal film in the vicinity of the third end of the dielectric film was removed. 21 and the sample No. in which the first groove was not formed. Sample No. 22 had a low withstand voltage, the insulation resistance was significantly reduced after the withstand voltage test, and the self-healing property did not function sufficiently. In addition, sample No. with t2 of 4.0 mm or less. Nos. 15 to 17, 19, and 20 had a small decrease in insulation resistance after the withstand voltage test.

A: Film capacitor C: Connection type capacitor D: Inverter E: Electric vehicle S: Shift part 1, 1a, 1b: Dielectric film 2, 2a, 2a1, 2a2, 2b: Metal film 2c, 2a1c, 2a2c: First metal Membranes 2d, 2a1d, 2a2d: Second metal membranes 2e, 2a1e, 2a2e: Extension parts of the first metal membrane 3: Main body portion 3a, 3b: Main body end portion 3c: Main body end faces 4, 4a, 4b: External electrode 5, 5a, 5b: Metallized film 6: Insulation margin part 7: Effective area 8: First groove 9: Second groove 10: Third groove 11: Fourth groove 21, 23: Bus bar 31: Bridge circuit 33 : Capacity part 35: Booster circuit 41: Motor 43: Engine 45: Transmission 47: Inverter 49: Power source 51a: Front wheel 51b: Rear wheel 53: Vehicle ECU
55: Ignition key 57: Engine ECU

Claims (11)

A rectangular dielectric film and a metal film are provided with a main body in which a plurality of layers are alternately laminated, and an external electrode,
The external electrodes are respectively provided on a pair of body end portions located at both ends of the body portion in the first direction,
The rectangular dielectric film has a first end and a second end located at both ends in the first direction, and a third end located at both ends in a second direction different from the first direction, Have
The metal film includes a first metal film, and one or more second metal films disposed between the first metal film and the third end portion,
The first metal film and the second metal film are separated from each other, and at least a part of the first metal film is connected to the external electrode at the end portion of the main body ,
A film capacitor , wherein the second metal film has a plurality of divided portions that are separated from each other . The film capacitor according to claim 1, further comprising a first groove between the first metal film and the second metal film. The film capacitor according to claim 2, wherein the first groove extends in the first direction. The film capacitor according to claim 1, wherein at least a part of the end surface of the second metal film in the second direction is located at the third end portion. The film capacitor according to claim 1, wherein at least one of the second metal films is not electrically connected to the external electrode. The first metal film electrically connected to the external electrode at the end of the main body is located at at least one of the first end and the second end and extends toward the third end. The film capacitor according to claim 1, wherein the film capacitor has an extending portion. The film capacitor according to claim 6, wherein the extending portion is accommodated in a portion having a distance of 4.0 mm or less from the first end portion or the second end portion where the extending portion is located. The film capacitor according to claim 6 or 7, wherein t2 is 0.05 mm or more, where t2 is a length of the extending portion in the first direction. A plurality of film capacitors, and a bus bar connecting the plurality of film capacitors,
A linked capacitor, wherein the film capacitor includes the film capacitor according to claim 1. A bridge circuit constituted by a switching element, and a capacitance section connected to the bridge circuit,
An inverter in which the capacitance section includes the film capacitor according to claim 1. A power source, an inverter connected to the power source, a motor connected to the inverter, and wheels driven by the motor,
An electric vehicle, wherein the inverter is the inverter according to claim 10.

Images