WO2018190437A1 - Film capacitor, connection-type capacitor, and inverter and electric vehicle in which said capacitors are used - Google Patents

Abstract

A film capacitor comprising: a body part 3 in which a plurality of rectangular dielectric films 1 and metal films 2 are laminated in alternating fashion; and an external electrode 4, the external electrode 4 being provided to each of a pair of body end parts 3a, 3b positioned at both ends in a first direction of the body part 3. The rectangular dielectric film 1 has a first end part 1c and a second end part 1d positioned at both ends in the first direction, and a third end part 1e positioned at both ends in a second direction that is different from the first direction. The metal film 2 includes a first metal film 2c and one or more of a second metal film 2d disposed between the first metal film 2c and the third end part 1e. The first metal film 2c and the second metal film 2d are separated, and at least a portion of the first metal film 2c is connected to the external electrode 4 by the body end part 3a or 3b.

Description

Film capacitor, coupled capacitor, inverter and electric vehicle using the same

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

The film capacitor has, for example, a dielectric film formed by forming a polypropylene resin into a film and a metal film formed on the surface of the dielectric film by vapor deposition. The metal film is used as an electrode. With such a configuration, in a film capacitor, even when a short circuit occurs in an insulation defect portion of the dielectric film, the metal film around the defect portion is evaporated and scattered by the short circuit energy, and the insulation defect portion is insulated. The film capacitor has an advantage that dielectric breakdown of the film capacitor can be prevented (self-recovery) (see, for example, Patent Document 1).

Thus, the film capacitor can prevent ignition and electric shock when the electric circuit is short-circuited. In recent years, the use of film capacitors has begun to be applied to power supply circuits such as LED (Light Emitting Diode) lighting, and has been expanded to drive motors for hybrid vehicles, inverter systems for photovoltaic power generation, and the like.

The structure of the film capacitor is classified into a wound type and a laminated type. In the multilayer film capacitor, the generation of wrinkles of the dielectric film and the deterioration of the insulation due to the wrinkles, which are found in the wound film capacitor, are unlikely to occur. On the other hand, multilayer film capacitors are often obtained by cutting a laminated body in which a plurality of dielectric films and metal films are laminated, so that it is possible to reduce the insulation deterioration of the cut surface by cutting the deposited metal part. As a purpose, a method of removing a metal film at a 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 portion in which a plurality of rectangular dielectric films and metal films are alternately stacked, and an external electrode. The external electrodes are respectively provided at a pair of body end portions located at both ends in the first direction of the body portion. The rectangular dielectric film includes 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 disposed between the first metal film and the third end portion, and the first metal film and the second metal film are In addition to being spaced apart, at least a part of the first metal film is connected to the external electrode at the end of the main body.

The connected capacitor according to the present disclosure includes a plurality of film capacitors and a bus bar connecting the plurality of film capacitors, and the film capacitor includes the film capacitor.

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

An electric vehicle according to the present disclosure is an electric vehicle including 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. It is.

It is a perspective view which shows a multilayer type film capacitor typically. It is a top view of FIG. 1A. It is one of the examples of the ii-ii sectional view taken on the line of FIG. 1A. 3 is another example of a cross-sectional view taken along line ii-ii in FIG. 1A. It is a top view of the metallized film of 1st 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. FIG. 4 is a sectional view taken along line iv-iv in FIG. 3A. It is a top view of the metallized film of 2nd Embodiment of FIG. 2A. It is the top view to which the broken-line part of FIG. 5A was expanded. 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 example of a change of a 2nd metal film. FIG. 6B is a sectional view taken along line vi-vi in FIG. 6A. It is a top view which shows one of the example of a change of a 2nd metal film. It is a top view which shows one of the example of a change of a 2nd metal film. It is a top view which shows one of the example of a change of a 2nd metal film. It is a perspective view which shows the structure of a connection type | mold capacitor | condenser typically. It is a schematic block diagram for demonstrating the structure 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 is composed of a film capacitor main body 3 and a pair of external electrodes 4a and 4b provided on the opposite end surfaces of the film capacitor main body 3 by metallicons. 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 stacked alternately.

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

In FIG. 1A, in 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 a first direction x, and the second direction y is a direction orthogonal to the first direction x. Yes. 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 obtained by forming a metal film 2a on one surface of the dielectric film 1a. The metallized film 5b is obtained by forming a metal film 2b on one surface of the dielectric film 1b. As shown in FIG. 2A, these metallized films 5a and 5b are laminated in a state slightly shifted in the width direction, that is, the first direction x. That is, the main body part 3 has a shift part S where the metallized films 5a and 5b do not overlap with the main body end parts 3a and 3b. A width in which the shift portion S is shifted is defined 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. The main body 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 in the first direction x of the body portion 3, respectively.

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

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

When there is a potential difference between the metal film 2a and the metal film 2b, an electrostatic capacity is generated in the effective region 7 where the metal film 2a and the metal film 2b overlap with the dielectric film 1 interposed therebetween.

<Series connection type>
2B, a metallized film 5a having a metal film 2a1 and a metal film 2a2 on the first surface 1ac of the dielectric film 1a, and a metal film 2b on the second surface 1bc of the dielectric film 1b. The metallized films 5b are alternately laminated. The metal film 2 a 1 is electrically connected to the external electrode 4 a at the first end 3 a of the main body 3. The metal film 2 a 2 is electrically connected to the external electrode 4 b at the second end 3 b 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 of FIG. 1 in the case of a series-connected film capacitor A. In FIG. 2B, the dielectric film 1a, the dielectric film 1b, the metal film 2a1, the metal film 2a2, and the metal film 2b have a width direction in the first direction x, a length direction in the second direction y, and a thickness direction in the third direction. z.

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

The metallized film 5a is obtained 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 at 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 obtained by forming a metal film 2b 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, a portion where the dielectric film 1b is exposed is continuously present in the second direction y. A so-called insulating margin 6b is provided. The width of the dielectric film 1b is slightly smaller than that of the dielectric film 1a.

These metallized films 5a and 5b are laminated in a state in which the metallized film 5a slightly protrudes on both sides in the first direction x, as shown in FIG. 2B. 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 with each other at the main body end portions 3a and 3b.

If there is a potential difference between the metal film 2a1 and the metal film 2b, a capacitance is generated in the effective region 7a where the metal film 2a1 and the metal film 2b overlap 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, an electrostatic capacity is generated in the effective region 7b where the metal film 2a2 and the metal film 2b overlap with the dielectric film 1a or 1b interposed therebetween. The first capacitor C1 having the effective region 7a and the second capacitor C2 having the effective region 7b are connected in series.

Hereinafter, unless otherwise specified, characteristics that can be applied to any film capacitor A in FIGS. 2A and 2B will be described.

The thickness of the dielectric film 1 may be, for example, 5 μm or less. A 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 in the vicinity of 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. The metal film 2 in the vicinity of 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 larger thickness than the metal film 2 having a self-recovering property that can be evaporated and scattered by short-circuit energy is generally a heavy edge regardless of whether or not it is positioned in the effective region 7. Sometimes called a department.

The thickness of the metal film 2 may be, for example, 20 nm or less, particularly 5 to 15 nm in the effective region 7. By setting the metal film 2 to such a thickness, the area resistance (sheet resistance) becomes 18 to 50Ω / □, and self-recovery can be exhibited. The thickness of the first metal film 2c and the thickness of the second metal film 2d may be the same. Either one of the metal film 2a and the metal film 2b may have a thickness of 20 nm or less, and the other may be 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 the effective region 7, that is, a range of 10 to 80 nm.

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

The second metal film 2d extends in a strip shape in the first direction x adjacent to the first metal film 2c, and is separated from the first metal film 2c. A first groove 8 extending in the first direction x exists between the first metal film 2c and the second metal film 2d. As shown in FIG. 4, there is no metal film at 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 need only 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 may not 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 in the vicinity of the main body end surface 3c. Therefore, the dielectric films 1a and 1b are less likely to adhere to each other in the vicinity of the main 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 main body end face 3c. As described above, in the first embodiment, the ability to escape the gas generated by the evaporation and scattering of the metal film 2 is improved, and the self-recoverability 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 portion of the second metal film 2d in the second direction y is located at the third end portion 1e, that is, faces the main body end surface 3c, the dielectric films 1a and 1b are formed near the main body end surface 3c. It becomes more difficult to adhere. As a result, the gas escape property is further improved, and the self-recovery property of the film capacitor A can be further enhanced.

Since the adhesion between the dielectric film 1 and the metal film 2 is relatively small compared to the adhesion when the dielectric films 1 are in direct contact with each other, the gas passes between the dielectric film 1 and the metal film 2 for comparison. It becomes easy to come off. In this case, at least a part of the end portion in the second direction y of the second metal film 2d only needs to be positioned at the third end portion 1e. Since at least a part of the end portion in the second direction y of the second metal film 2d is located at the third end portion 1e, that is, located at the main body end surface 3c, a path through which gas escapes through the main body end surface 3c is secured. The slipping out property is improved.

In the first embodiment, the second metal film 2d may be connected to the external electrode at the main 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 part 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, particularly 2 to 5 mm, it is possible to obtain a film capacitor A that secures electrostatic capacity and has an excellent self-healing function. The range of W1 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. The extending portion 2e may be provided. FIG. 5B is an enlarged plan view of the broken line portion of FIG. 5A. When the first metal film 2c has the extended portion 2e in the vicinity of the first end 1c, the area of the connection portion between the first metal film 2c and the external electrode 4 is increased, and the resistance of the connection portion can be reduced. As shown in FIG. 5C, the extension 2e may be located in the vicinity of the second end 1d.

For example, in the film capacitor A shown in FIG. 2A, the vicinity of the first end 1ac of the dielectric film 1a is a state in which the metallized film 5a and the metallized film 5b are laminated, and the dielectric film 1a is a dielectric. The point which overlaps the margin part 6b of the film 1b is pointed out. That is, the metal film 2ac electrically connected to the external electrode 4a at the main body end 3a where the first end 1ac is located has the extension 2e at the third end 1e in the vicinity of the first end 1ac. 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. Point to. That is, the metal film 2bc electrically connected to the external electrode 4b at the main body end 3b where the first end 1bc is located has the extension 2e at the third end 1e in the vicinity of the first end 1bc. Only. In FIG. 5A, the symbols a and b are omitted in order to explain the features common to the metallized films 5a and 5b in 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.

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 are, 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. That is, as shown in FIG. 5C, at the third end 1e in the vicinity of the first end 1ac, the metal film 2a1c electrically connected to the external electrode 4a at the body end 3a where the first end 1ac is located is formed. In the third end 1e having the extending portion 2e and in the vicinity of the second end 1ad, the metal film 2a2c electrically connected to the external electrode 4b is extended at the body end 3b where the second end 1ad is located. It has a protruding portion 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 where 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 extending portion 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 to the third end portion 1e toward the third end portion 1e in the vicinity of the first end portion 1c or the second end portion 1d. ing. Due to the first groove 8, the first metal film 2 c and the second metal film 2 d are separated 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 main body end surface 3c of the main body portion 3, 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 portion closest to the second end 1d of the extending portion 2e and the first end 1c is t2, and the first groove 8, the width at the third end 1e is t3. In other words, the extending part 2e is housed in a part whose distance from the first end part 1c is t2 or less. The width t1 of the margin portion 6 may be, for example, not less than 1.5 mm and not more than 3.0 mm. The shift amount s of the shift portion S may be, for example, 0.2 mm or more and 1.0 mm or less. t3 may be, for example, 0.15 mm or more. For example, t2 may be set such that the sum of t2 and t3 is equal to or less than the sum of t1 and s, that is, (t2 + t3) ≦ (t1 + s). By satisfying (t2 + t3) ≦ (t1 + s), the insulation deterioration of the film capacitor A itself can be further reduced.

T2 may specifically be 4.0 mm or less, for example, 2.0 mm or less, and particularly 1.8 mm or less. Moreover, t2 may be 0.05 mm or more, for example. When the margin portion 6 having the general width t1 and the film capacitor A having the general shift width s are set to t2 in such a range, the insulation deterioration of the film capacitor A itself can be further reduced. The above relationship shows the relationship between t1, t2, t3 and s located at the main body end 3a, and also shows the relationship between t1, t2, t3 and s located at the main body end 3b. .

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

The second metal film 2d may have a plurality of divided portions 2di that are separated from each other. 6A and FIGS. 7A to 7C each correspond to an enlarged plan view of the broken line portion of 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 divided portions 2di. 6B is a cross-sectional view taken along the line vi-vi in FIG. 6A. 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 a third groove 10 extending in the second direction y. The third groove 10 may be connected to the first groove 8. The 2nd groove | channel 9 and the 3rd groove | channel 10 are the space | gap which spaces apart the some division | segmentation site | part 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 exist 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 detachability 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, none of them is connected to the external electrode 4, and even if the divided portions 2di located in different layers come into contact with each other at the main body end surface 3c of the main body 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, the angle is set with respect to the first direction x and the second direction y. The second metal film 2d may be divided into a plurality of divided portions 2di by the fourth groove 11 that is provided. The fourth groove 11 includes two kinds of grooves extending in at least two different directions, and the two kinds of grooves may intersect each other. At this time, the first groove 8 may be linearly extended in the first direction x. However, as shown in FIG. 7B, the first groove 8 is in two different directions as in the fourth groove 11. The extending groove may be connected to form the first groove 8. In this case, the region where the first groove 8 is disposed may extend in the first direction x. In FIG. 7B, it can be said that the first groove 8 is a portion of the fourth groove 11 located closest to the first metal film 2c. At this time, W1 is the minimum value of the distance between the third end 1e in the second direction y and the first part 2c forming the effective region 7.

W2 shown in FIGS. 6A, 6B, 7A, and 7B is the width of the first groove 8. FIG. P1 shown in FIGS. 6A, 6B, and 7A is an interval (pitch) between the plurality of second grooves 9, and P2 shown in FIG. 7A is an 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 0.10 to 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, the discharge between the first metal film 2c and the second metal film 2d can be suppressed. , Gas detachability can be secured.

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

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

The bottoms of the second groove 9, the third groove 10, and the fourth groove 11 have no metal film, that is, the dielectric film 1 may be exposed, but the first metal film 2c, the second metal film You may be comprised with the metal film 2 whose thickness is thinner than 2d. That is, the depth in the z direction of the second groove 9, the third groove 10, and the fourth groove 11 may be smaller than the thickness in the z direction of the second metal film 2d.

As described above, the second metal film 2d may be constituted by the divided portion 2di divided by the first groove 8, the second groove 9, the third groove 10, and the fourth groove 11, As shown to FIG. 7C, you may be comprised by the division | segmentation site | part 2di arrange | positioned at 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 divided portion 2di is formed in a strip shape or a rectangular shape. However, the shape is not limited to this, and the division is not limited to this. The part 2di may be used.

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

Such a film capacitor A is a film capacitor that has high insulation properties, good gas escape characteristics even when the dielectric breakdown partially occurs, and an excellent self-healing 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 a high dielectric breakdown voltage.

In addition, cycloolefin polymer (COP) and polyarylate (PAR) have high adhesion between films when formed into a film and gas tends not to evaporate. However, the second metal film 2d as described above is provided. As a result, a large self-recovery improvement effect can be obtained.

The dielectric film 1 is obtained, for example, by forming a resin solution in which an insulating resin is dissolved in a solvent into a sheet shape on a surface of a base material made of, for example, polyethylene terephthalate (PET), and drying to volatilize the solvent. It is done. 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. Solvents used for molding include, for example, 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. Further, a resin film produced by a melt extrusion method may be stretched.

The dielectric film 1 may be composed of only the insulating resin described above, but may include other materials. Examples of components other than the resin contained in the dielectric film 1 include the above-described organic solvents and inorganic fillers. As the inorganic filler, for example, inorganic oxides such as alumina, titanium oxide, and silicon dioxide, inorganic nitrides such as silicon nitride, glass, and the like can be used. In particular, when a material having a high relative dielectric constant such as a composite oxide having a perovskite structure is used as the inorganic filler, the relative dielectric constant of the entire dielectric film 1 is improved, and the film capacitor can be reduced in size. 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, a composite film containing less than 50% by mass of the inorganic filler and 50% by mass or more of the resin is used to maintain the flexibility of the resin. Effects such as improvement of relative dielectric constant can be obtained. The size (average particle diameter) of the inorganic filler may be 4 to 1000 nm.

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

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

A pattern is formed on the metal film 2 as necessary. For the pattern formation of the metal film 2, a laser marker machine or a laser trimmer machine capable of skipping a 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.

<Production method of film capacitor>
The multilayer film capacitor A of the present disclosure may be manufactured as follows. After the metallized film 5 (5a, 5b) having the metal film 2 (2a, 2b) on one surface is cut into a desired shape, a plurality of layers are laminated to obtain a laminate. At this time, in the structure shown in FIG. 2A, the metallized films 5a and 5b are alternately stacked so that the margin portions 6a and 6b are located at different end portions in the first direction x. Moreover, as shown in FIG. 2A, the metallized films 5a and 5b are overlapped with each other while being slightly shifted in the first direction x. In the case of the structure shown in FIG. 2B, a metallized film 5a having a margin 6a in the center of the first direction x, and a width in the first direction x slightly smaller than that, and margin portions 6b at both ends of the first direction x. The metallized films 5b are alternately laminated as shown in FIG. 2B.

The main body part 3 of an individual piece is obtained by cut | disconnecting the obtained laminated body. At this time, the surface in the vicinity of the portion to be cut is irradiated with 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 transmits the laser, the metal film 2 in the layer irradiated with the laser is removed, so that the metal film 2 in the next layer is irradiated with the laser. Therefore, the 1st groove | channel 8 can be formed in all the same positions of the laminated | stacked metallized film 5 by irradiating the surface of a laminated body with a laser.

The main body 3 having the cut surface as the third end 1e is obtained by cutting the laminate along the formed first groove 8 in the vicinity thereof. In the laminated body, two first grooves 8 are formed with a cut portion interposed therebetween, and the laminated body is cut between the two first grooves 8. Thereby, the main body 3 having the first metal film 2c and the second metal film 2d disposed between the first metal film 2c and the third end 1e is obtained.

The film capacitor A is obtained by forming the metallicon electrodes on both end faces in the first direction x of the main body 3 to be the external electrodes 4. For the formation of the external electrode 4, for example, metal spraying, sputtering, plating, or the like is suitable.

Next, if necessary, the surface of the main body 3 on which the external electrode 4 is formed 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.

Also, the material of the metallicon electrode includes at least one metal material selected from zinc, aluminum, copper and solder.

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 addition to the first groove 8, the second groove 9, the third groove 10, the fourth groove 11, and the like are formed, and when the plurality of divided portions 2 di are formed in the second metal film 2 d, The first groove 4 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 embodiment of a coupled capacitor. In FIG. 8, the case and the mold resin are omitted for easy understanding of the configuration. In the coupled 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 lead terminal portions 21b and 23b connected to the external connection terminal portions 21a and 23a and the external electrodes 4a and 4b of the film capacitor A, respectively.

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

The connection type capacitor C is formed by attaching bus bars 21 and 23 to the external electrodes 4a and 4b formed on both ends of the main body part 3 with bonding materials in a state where a plurality of, for example, four film capacitors are arranged. can get.

Note that the film capacitor A and the connected capacitor C can be made into a resin mold type (case mold type) capacitor after being accommodated in the case and filled with a resin in the gap in the case.

<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 generates alternating current from direct current. As shown in FIG. 9, the inverter D of the present embodiment includes a bridge circuit 31 composed of 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 disposed between the terminals. The inverter D includes the film capacitor A described above as the capacitor unit 33.

The inverter D is connected to a 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 source (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 a drive source. 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 entire electric vehicle E. The engine ECU 57 controls the rotational speed of the engine 43 to drive the electric vehicle E. The electric vehicle E further includes driving devices such as an ignition key 55 operated by the 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 rotational 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 connected capacitor C is applied as the capacity unit 33 is used. In such an electric vehicle E, since the film capacitor A is excellent in self-recovery, the electrostatic capacity can be maintained for a long period of time, and the switching noise generated in the inverter 47 or the like can be reduced for a long period of time. it can.

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

A dielectric film having an average thickness of 3 μm was prepared using ZEONOR (registered trademark) (manufactured by ZEON), which is a cyclic cycloolefin resin. ZEONOR (registered trademark) (manufactured by Nippon Zeon) was dissolved in toluene, applied onto a polyethylene terephthalate (PET) substrate using a coater, and molded into a sheet. After molding, heat treatment was performed at 130 ° C. to remove toluene, and a dielectric film was obtained.

The obtained dielectric film was peeled off from the substrate and slitted to a width of 130 mm, and then a 97 mm wide Al metal film was formed by vacuum deposition using a metal mask as a metal film on one main surface of the dielectric film. Formed.

Next, 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 scanning speed of 4 m / second.

A 130 mm wide metallized film was further slit to obtain a 50 mm wide metallized film having a 1.5 mm insulation margin (a metal film non-formed part where the dielectric film was exposed).

This metallized film was overlapped so that the metal film faced through the dielectric film, to produce a laminate. In addition, it laminated | stacked so that the insulation margin part of a metallized film might be alternately arrange | positioned on the different side of the 1st direction x. Moreover, the metallized film was laminated | stacked in the state which shifted | deviated 0.5 mm in the 1st direction x for every layer, as shown to FIG. 2A. The number of layers was 100.

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

A film capacitor was obtained by spraying an alloy of zinc and tin on the opposing end faces in the first direction x of the main body to form a metallicon electrode as an external electrode.

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 AC 1 V and 1 kHz. The insulation resistance and withstand voltage were measured using an insulation resistance meter. The withstand voltage was a voltage when a DC voltage was applied to the film capacitor at a boosting rate of 0 V to 10 V per second using an insulation resistance meter, and the leakage current reached 0.01 A.

Sample No. In Nos. 1 to 20, the decrease in insulation resistance before and after the withstand voltage test was small, and the self-recovering property was excellent. On the other hand, the sample in which the second metal film was not formed, that is, the sample No. 1 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. No. 22 had a low withstand voltage, the insulation resistance greatly decreased after the withstand voltage test, and the self-recovery did not function sufficiently. In addition, sample No. with t2 of 4.0 mm or less In Nos. 15 to 17, 19 and 20, the decrease in insulation resistance was small after the withstand voltage test.

A: Film capacitor C: Connection type capacitor D: Inverter E: Electric vehicle S: Shifting part 1, 1a, 1b: Dielectric film 2, 2a, 2a1, 2a2, 2b: Metal film 2c, 2a1c, 2a2c: First metal Film 2d, 2a1d, 2a2d: second metal film 2e, 2a1e, 2a2e: first metal film extension part 3: main body part 3a, 3b: main body end part 3c: main body end face 4, 4a, 4b: external electrode 5, 5a, 5b: Metallized film 6: Insulation margin 7: Effective area 8: First groove 9: Second groove 10: Third groove 11: Fourth groove 21, 23: Bus bar 31: Bridge circuit 33 : Capacitor 35: Booster circuit 41: Motor 43: Engine 45: Transmission 47: Inverter 49: Power supply 51a: Front wheel 51b: Rear wheel 53: Vehicle ECU
55: Ignition key 57: Engine ECU

Claims (12)

1. A rectangular dielectric film and a metal film, and a plurality of alternately laminated main body portions and external electrodes,
   The external electrodes are respectively provided at a pair of body end portions located at both ends in the first direction of the body portion,
   The rectangular dielectric film includes 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,
   The film capacitor, wherein 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 of the main body.
2. The film capacitor according to claim 1, further comprising a first groove between the first metal film and the second metal film.
3. The film capacitor according to claim 2, wherein the first groove extends in the first direction.
4. 4. The film capacitor according to claim 1, wherein at least a part of the end surface in the second direction of the second metal film is located at the third end.
5. 5. The film capacitor according to claim 1, wherein at least one of the second metal films is not electrically connected to the external electrode.
6. 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. 6. The film capacitor according to claim 1, wherein the film capacitor has an extending portion.
7. The film capacitor according to claim 6, wherein the extension portion is housed in a portion having a distance of 4.0 mm or less from the first end portion or the second end portion where the extension portion is located.
8. The film capacitor according to claim 6 or 7, wherein when the length of the extending portion in the first direction is t2, the t2 is 0.05 mm or more.
9. The film capacitor according to any one of claims 1 to 8, wherein the second metal film has a plurality of divided parts spaced apart from each other.
10. A plurality of film capacitors, and a bus bar connecting the plurality of film capacitors,
    A connected capacitor, wherein the film capacitor includes the film capacitor according to any one of claims 1 to 9.
11. A bridge circuit configured by a switching element, and a capacitor connected to the bridge circuit,
    An inverter, wherein the capacitor section includes the film capacitor according to any one of claims 1 to 9.
12. A power source, an inverter connected to the power source, a motor connected to the inverter, and a wheel driven by the motor,
    An electric vehicle, wherein the inverter is the inverter according to claim 11.

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