JP6737818B2 - Film capacitors, concatenated capacitors, inverters, and electric vehicles - Google Patents

Description

The present disclosure is full I Lum capacitor, coupling capacitor, an inverter, and an electric vehicle.

The film capacitor has, for example, a dielectric film formed by filming 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 defect portion of the dielectric film, the metal film around the defect portion is evaporated and scattered by the energy of the short circuit, and the insulation defect portion is insulated. , Has the advantage of being able to prevent the dielectric breakdown of the film capacitor (self-healing property) (for example, refer to 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 begun to be applied to power supply circuits such as LED (Light Emitting Diode) lighting, and is expanding to motor drives for hybrid vehicles and inverter systems for solar power generation. See, for example, Patent Document 2.

In order for the self-healing property of the film capacitor as described above to function, it is important that the gas generated when the metal film around the defective portion evaporates and scatters. In particular, since it is difficult for gas to escape near the so-called insulating margin portion where adjacent dielectric films are in close contact with each other, for example, a method is disclosed in which the surface roughness of the dielectric film in the margin portion is roughened to ensure gas escape. (See Patent Document 3).

JP-A-9-129475 JP, 2010-178571, A JP, 2015-201527, A

Film capacitor of the present disclosure, external metallic film coated film is provided, respectively a body part is a wound body which is wound multiple times, a pair of body end portion positioned in the axial direction of the body portion An electrode is provided, and the metal film-attached film includes a rectangular dielectric film and a metal film arranged on one surface of the dielectric film . The dielectric film has a first end face located on one side in the first direction of the dielectric film and a second end face located on the other side. The metal film has a first portion arranged on the first end surface side of the dielectric film and a second portion arranged on the second end surface side of the dielectric film, and the first portion. And the second portion are separated from each other by a first groove extending in a second direction orthogonal to the first direction of the dielectric film. It said body portion is at said body end portion of one said first portion is one, by Rukoto connected to the external electrode has an effective area that expresses capacitance. The metal film has a third portion, and the third portion is separated from the first portion by a sixth groove extending from one end to the other end in the axial length direction in the effective region. In addition, it is not electrically connected to any of the pair of external electrodes. The length of the third portion in the second direction is equal to or greater than one turn of the winding, and the distance from the center of the winding of the main body is 1/2 the distance from the center to the outer periphery. Also, at least one is arranged in a small position .

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

The inverter of the present disclosure is an inverter that includes a bridge circuit configured by a switching element and a capacitance unit connected to the bridge circuit, and the capacitance unit is the above-described film capacitor or connection type capacitor.

The electric vehicle of the present disclosure includes a power source, the above-mentioned inverter connected to the power source, a motor connected to the inverter, and wheels driven by the motor.

It is a schematic sectional drawing of a laminated film capacitor. It is a development perspective view showing typically composition of a winding type film capacitor. It shows a part of the film with a metal film, (a) is a plan view, (b) is a cross-sectional view. It is a schematic sectional drawing of a laminated film capacitor. It is a development perspective view showing typically composition of a winding type film capacitor. It shows a part of the film with a metal film of the second embodiment, (a) is a plan view, (b) is a cross-sectional view. FIG. 3 shows a part of a film with a metal film of Modification 1, (a) is a plan view and (b) is a sectional view. FIG. 7A is an enlarged view of the one-dot chain line portion of FIG. 7A, in which FIG. 7A is a plan view and FIG. (A) And (b) is a top view which shows a part of 2nd site vicinity of the film with a metal film in another embodiment. FIG. 10 shows a part of a film with a metal film of Modification 2, (a) is a plan view, and (b) and (c) are cross-sectional views. The state which piled up a set of films with a metal film in the modification 2 is demonstrated, (a) is a top view of the surface of a film with a metal film, (b) is an xz sectional view. FIG. 11 is a cross-sectional view corresponding to a cross-sectional view taken along line XX of FIG. 10A, for explaining a state in which a pair of films with metal films in Modified Example 2 are stacked. The cross section perpendicular|vertical to the axial direction of the film capacitor of the modification 2 is shown typically, (a) is a sectional view when it has one 3rd part, (b) has two 3rd parts. FIG. 10A is an enlarged plan view of an alternate long and short dash line portion of FIG. 10A, and FIG. 10B is an enlarged plan view of a portion corresponding to the alternate long and short dash line portion of FIG. 10A in another example. It is a perspective view which shows the structure of a connection type capacitor 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. 1 and 2, the film capacitor includes a film capacitor main body portion 3 (hereinafter also simply referred to as a main body portion 3) in which a dielectric film 1 and a metal film 2 are laminated or wound, and a main body portion. It is constituted by a pair of external electrodes 4a and 4b provided by metallikon on the end faces facing each other.

<Multilayer film capacitor>
In the body portion 3 of the laminated film capacitor A shown in FIG. 1, a film 5a with a metal film having a metal film 2a on one surface of the dielectric film 1a and a metal film 2b having a metal film 2b on one surface of the dielectric film 1b. Films with films 5b are alternately laminated. The metal film 2a is electrically connected to the external electrode 4a at one end of the main body 3. The metal film 2b is electrically connected to the external electrode 4b at the other end of the main body 3.

In FIG. 1, the first direction of the dielectric films 1a and 1b and the metal films 2a and 2b is shown as the x direction (width direction), the second direction is shown as the y direction (length direction), and the thickness direction is shown as the z direction. There is.

<Wound film capacitor>
In the body part 3 of the film capacitor B shown in FIG. 2, a film 5a with a metal film having a metal film 2a on one surface of the dielectric film 1a and a film with a metal film 2b having a metal film 2b on one surface of the dielectric film 1b. 5b is overlapped and wound. The metal film 2a is electrically connected to the external electrode 4a at one end of the main body 3. The metal film 2b is electrically connected to the external electrode 4b at the other end of the main body 3.

The body 3 is formed by stacking and winding a dielectric film 1a, a metal film 2a, a dielectric film 1b and a metal film 2b in this order. The external electrodes 4a and 4b are a pair of metallikon electrodes provided on opposite end surfaces of the main body 3. Note that, in FIG. 2, for easy understanding, the drawn dielectric films 1a and 1b and the metal films 2a and 2b are drawn such that the thickness thereof becomes thicker toward the front of the paper.

In FIG. 2, the first direction of the dielectric films 1a and 1b and the metal films 2a and 2b is shown as the x direction (width direction), the second direction is shown as the y direction (length direction), and the thickness direction is shown as the z direction. There is.

The film with metal film 5a is obtained by forming the metal film 2a on one surface of the dielectric film 1a. The film 5b with a metal film is obtained by forming the metal film 2b on one surface of the dielectric film 1b. As shown in FIGS. 1 and 2, these films 5a and 5b with a metal film are laminated or wound in a state of being slightly displaced in the width direction (first direction, x direction).

Thus, in the film capacitors A and B, the film 5a with a metal film formed of the dielectric film 1a and the metal film 2a and the film 5b with a metal film formed of the dielectric film 1b and the metal film 2b are As shown in FIGS. 1 and 2, they are stacked, laminated or wound.

The metal films 2a and 2b are connected to the external electrodes 4a and 4b, respectively, at connection portions exposed at different ends of the main body 3 located in the first direction (x direction).

In order to describe the features of this embodiment that are common to the films 5a and 5b with a metal film, the reference numerals a and b may be omitted below as shown in FIG. Further, in the cross-sectional view, the thickness direction (z direction) of the film is enlarged and shown for ease of explanation.

The dielectric film 1 has a first end surface 1c located on one side in the first direction (width direction) and a second end surface 1d located on the other side. 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 surface. In the vicinity of the insulation margin portion 6, the adjacent dielectric films 1a and 1b are actually in close contact with each other, and the gas generated at the time of dielectric breakdown is difficult to escape, and a sufficient self-recovery function cannot be obtained.

<First Embodiment>
In the first embodiment, as shown in FIGS. 3A and 3B, the metal film 2 includes the first portion 2c disposed on the first end face 1c side and the first portion 2c disposed on the second end face 1d side. It has two parts 2d.

The second portion 2d is adjacent to the first portion 2c, extends in a band shape in the y direction (length direction, circumferential direction of winding) that is the second direction, and is electrically separated from the first portion 2c. Insulated. A first groove 7 extending in the y direction (length direction, circumferential direction of winding), which is the second direction, is present between the first portion 2c and the second portion 2d. The dielectric film 1 is exposed at the bottom of the first groove 7, and the first portion 7 separates the first portion 2c from the second portion 2d by the first groove 7.

Thus, in this embodiment, the metal film 2 has the first portion 2c and the second portion 2d. The second portion 2d located near the second end face 1d is electrically insulated from the first portion 2c connected to the external electrode 4 by the first groove 7. Therefore, even if a voltage is applied to the film capacitors A and B, no electric field is applied to the second portion 2d, and dielectric breakdown occurs in the vicinity of the insulation margin portion 6 where the dielectric films 1a and 1b are in close contact and joined. Can be suppressed.

Further, since the first groove 7 is present in the vicinity of the insulation margin portion 6, even if a dielectric breakdown occurs in a portion of the first portion 2c adjacent to the second portion 2d, the metal film 2 evaporates and scatters. The escape property of the gas generated at that time (hereinafter, also sometimes referred to as gas) is improved by the first groove 7, and the self-recovery property of the film capacitors A and B can be improved.

<Second Embodiment>
As shown in FIGS. 4 and 5, the first portion 2c of the metal film 2 has an end face located at the first end face 1c of the dielectric film 1, and the second portion 2d is the second end of the dielectric film 1. You may have the end surface located in the end surface 1d. That is, of the end faces of the first portion 2c in the first direction (width direction, x direction), the end face on the first end face 1c side of the dielectric film 1 (the end face on the side opposite to the first groove 7 side) is Of the end faces of the second portion 2d in the first direction (width direction, x direction) located on the first end face 1c of the dielectric film 1, the end face on the second end face 1d side of the dielectric film 1 (first groove). The end surface opposite to the 7 side) may be located on the second end surface 1d of the dielectric film 1.

In other words, when the film 5 with a metal film is viewed in a plan view, as shown in FIG. 6, the end surface of the first portion 2c on the first end surface 1c side overlaps with the first end surface 1c and the second portion 2d The end face on the side of the end face 1d overlaps with the second end face 1d. As described above, in the film 5 with a metal film of the present embodiment, the second portion 2d of the metal film 2 is usually provided in the portion where the metal film 2 is not provided and the dielectric film 1 is exposed. Good. That is, the film 5 with a metal film of the present embodiment may not have the so-called insulating margin portion 6.

In the second embodiment, the end surface of the first portion 2c of the metal film 2 on the first end surface 1c side (hereinafter, sometimes simply referred to as the end surface of the first portion 2c) and the first end surface 1c of the dielectric film 1 are Although they are overlapped with each other, the end surface of the first portion 2c and the first end surface 1c of the dielectric film 1 may be slightly displaced. Further, the end surface of the second portion 2d of the metal film 2 on the second end surface 1d side (hereinafter, sometimes simply referred to as the end surface of the second portion 2d) and the second end surface 1d of the dielectric film 1 are overlapped with each other. However, the end surface of the second portion 2d and the second end surface 1d of the dielectric film 1 may be slightly displaced. In the process of producing the film 5 with a metal film or the film capacitors A and B, a dielectric is provided between the end surface of the first portion 2c and the first end surface 1c or between the end surface of the second portion 2d and the second end surface 1d. The exposed part of the body film 1 may be formed.

Since the end surface of the first portion 2c needs to be connected to the external electrode 4 on the side of the first end surface 1c, the end surface of the first portion 2c is more likely to be exposed than the exposed portion of the dielectric film 1 with the first end surface 1c. It is preferable that the first end surface 1c is overlapped with, protrudes from the first end surface 1c, or covers the first end surface 1c. On the other hand, the end surface of the second portion 2d does not have to be connected to the external electrode 4 on the second end surface 1d side, and even if the second surface 2d has an exposed portion of the dielectric film 1 slightly between the second end surface 1d and the second end surface 1d. Good. If there are many exposed portions of the dielectric film 1 on the side of the second end face 1d, the dielectric films 1 of different layers will adhere to each other over a wide area, and there is a concern that the gas escape property will deteriorate. It is preferable that the exposed portion of the body film 1 be slight or that the end surface of the second portion 2d and the second end surface 1d overlap each other.

When a film 5 with a metal film having a regular pattern such as a mesh pattern is used for the entire metal film 2, the films 5a and 5b with a metal film are wound to form a wound film capacitor. When set to B, wrinkles were likely to occur along the pattern of the metal film 2, and there was a risk of dielectric breakdown at the wrinkles. On the other hand, the film with metal film 5 of the present embodiment has the first groove 7 in the vicinity of the second end face 1d. The shape of the first groove 7 is different from the pattern (for example, a mesh pattern) provided in the first portion 2c. Therefore, when the film 5 with metal film (5a, 5b) of the present embodiment is wound to form a wound type film capacitor B, the first portions 2c (2ac, 2bc) of the metal films 2a and 2b overlap each other. Wrinkles are less likely to occur in a region, that is, an effective region to which an electric field is applied (hereinafter, may be simply referred to as an effective region), and the withstand voltage of the film capacitor B is improved.

In particular, in the second embodiment, since the insulating margin portion 6 is not provided and the end surface of the second portion 2d and the second end surface 1d of the dielectric film 1 overlap, the dielectric films 1a and 1b are in close contact with each other. Hateful. Therefore, the gas generated during the dielectric breakdown is more likely to escape. In addition, the sliding property between the films 5a and 5b with the metal film is improved, and the effect of further suppressing the generation of wrinkles during winding is also obtained.

As shown in FIG. 3A and FIG. 6, the length of the dielectric film 1 in the first direction (width direction, x direction) is W1, and the second direction between the second end face 1d and the first portion 2c ( The distance in the width direction and the x direction) is W2. At this time, the ratio of W2 to W1 (W2/W1) is preferably 0.23 or less. W2 is the distance in the first direction (width direction, x direction) between the second end surface 1d and the end surface of the first portion 2c on the second end surface 1d side. Therefore, the second portion 2d exists in a region where the distance from the second end face 1d is W2 or less.

When W2/W1 is larger than 0.23, the effective regions where the first portions 2c of the metal films 2a and 3b are overlapped with each other are small and the electrostatic capacitance is reduced, and the desired electrostatic capacitance is ensured. There is a concern that size A) will need to be increased. In particular, W2 is preferably in the range of 0.5 to 2.0 mm. By setting W2 to 0.5 mm or more, the self-healing property of the film capacitor A can be improved.

Further, by setting W2 to have the same width as a heavy edge portion described later, it is possible to suppress dielectric breakdown in the heavy edge portion.

<Modification 1>
As shown in FIGS. 7 and 8, the second portion 2d may be composed of a plurality of divided portions 2di divided by the second groove 8. FIG. 8 is an enlarged plan view of the one-dot chain line portion of FIG. 7. The second groove 8 extends in the second direction (length direction, y direction). The second portion 2d may be composed of a plurality of divided portions 2di divided by the third groove 9 extending in the first direction (width direction, x direction). As described above, the presence of the second groove 8 and the third groove 9 in addition to the first groove 7 further improves the gas escape property.

It is particularly preferable that the second portion 2d has a second groove 8 extending in the second direction (length direction, y direction) as shown in FIG. By having the second groove 8 extending in the second direction, the gas escape property can be further improved. Further, as shown in FIG. 9A, it has both a second groove 8 extending in the second direction and a third groove 9 extending in the first direction (width direction, x direction). Is good.

The third groove 9 extending in the first direction (width direction, x direction) may have an angle with respect to the first direction (width direction, x direction) of the film 5 with a metal film. In this case, by periodically changing the angle of the third groove 9 with respect to the first direction (width direction, x direction), when the metal film-attached film 5 is laminated or wound, the third grooves 9 can be separated from each other. They do not overlap with each other, and the gas escape property is further improved.

When the length of the divided portion 2di of the second portion 2d in the first direction (width direction, x direction) is W3, W3 is preferably in the range of 0.01 to 0.20 mm. By setting the width W3 of the divided portion 2di to 0.01 to 0.20 mm, it is possible to secure the gas escape property. Further, when W3 is in such a range, it is possible to fabricate the divided portion 2di by a laser or an oil margin.

The width W4 of the first groove 7 in the first direction (width direction, x direction) is preferably in the range of 0.01 to 0.20 mm. By setting the width W4 of the first groove 7 to 0.01 to 0.20 mm, it is possible to suppress the discharge between the first portion 2c and the second portion 2d of the metal film 2 and ensure the gas escape property. it can.

The widths of the second groove 8 and the third groove 9 are not particularly limited, but may be in either the first direction (width direction, x direction) or the second direction (length direction, y direction). For example, the range may be 0.01 to 0.20 mm, which is the same as that of the first groove 7. Although the dielectric film 1 may be exposed at the bottoms of the second groove 8 and the third groove 9, the bottom of the second groove 8 and the third groove 9 is composed of the metal film 2 having a smaller thickness than the first portion 2c and the second portion 2d. May be. That is, the depths of the second groove 8 and the third groove 9 in the z direction may be smaller than the thickness of the metal film 2 in the z direction.

The second portion 2d may be formed by the divided portion 2di divided by the first groove 7, the second groove 8 and/or the third groove 9 as described above, but FIG. 9(b). As shown in, it may be configured by the divided parts 2di arranged in a stepping stone shape. When the divided portions 2di are arranged in a stepping stone shape, the ratio of the area occupied by the divided portions 2di is preferably, for example, 25 to 50%.

In addition, although the divided portion 2di is formed into a strip shape or a rectangular shape in FIGS. 7 to 9, the divided portion 2di is not limited to this, and may be a triangular shape, a polygonal shape, a circular shape, an elliptical shape, or an indefinite shape.

<Modification 2>
In the film capacitor B having the wound main body portion 3, as shown in FIGS. 10 and 11, the metal film 2 preferably has a third portion 2e which is not connected to the external electrode 4 in addition to the second portion 2d. .. As shown in FIG. 11C, the third portion 2e that is not connected to the external electrode 4 is a region (effective region) 13 where the metal films 2a and 2b overlap each other with the dielectric film 1 (1a, 1b) interposed therebetween. , Which is not connected to the external electrode 4. Although the region where the metal films 2a and 2b are overlapped with each other and which exhibits the electrostatic capacitance is usually referred to as an effective region, here, for convenience sake, even in the third portion 2e which is not connected to the external electrode 4 and does not exhibit the electrostatic capacitance, A region where the metal films 2a and 2b overlap each other is referred to as an effective region 13. Both ends of the third portion 2e in the first direction (width direction, x direction), that is, the regions overlapping the second portions 2d and 2d of the metal film 2 may be electrically connected to the external electrode 4.

As shown in FIG. 10A, the third portion 2e includes a fourth groove 10 extending in the axial direction (first direction, x direction) and a fourth groove 10 along the circumferential direction of winding (second direction, y direction). 5 and a sixth groove 12 extending from one end to the other end in the axial direction (width direction, x direction). It can be said that the sixth groove 12 extends from one end of the fourth groove 10 in the axial direction (width direction, x direction) to the other end.

The third portion 2e is electrically insulated from the external electrode 4 by the fifth groove 11, and is electrically insulated from the first portion 2c by the sixth groove 12. The dielectric film 1 is exposed at the bottoms of the fifth groove 11 and the sixth groove 12, whereby the third portion 2e and the external electrode 4 are electrically insulated, and the third portion 2e. And the first portion 2c are electrically insulated.

The third portion 2e may be provided on only one of the metal films 2a and 2b. Further, it may be provided on both of the metal films 2a and 2b. FIGS. 10B and 10C are cross-sectional views taken along line XX of FIG. 10A, showing the overlapping state of the films 5a and 5b with a metal film. When the third portion 2e is provided on both of the metal films 2a and 2b, as shown in FIG. 12, the third portion 2e of the metal film 2a and the third portion 2e of the metal film 2b are connected to the dielectric film 1 ( 1a, 1b) may be arranged so as to face each other with the sandwiching therebetween. By arranging in this way, the influence on the capacitance of the film capacitor B can be minimized.

The third portion 2e is arranged in the second direction (the winding circumferential direction, the y direction), that is, in at least a part of the radial direction of the main body portion 3, and the length L in the y direction is the third portion 2e. It is preferable that the number of turns is one or more turns in the wound portion. That is, as shown in FIG. 13, the third portion 2e is arranged at a position where the distance from the winding center O is r, and the length L thereof is equal to or greater than one round at the position of the radius r, that is, 2πr. That is all. In addition, in FIG. 13, the films 5 a and 5 b with a metal film are wound around the cylindrical core body 14, and the center O of winding is the center of the core body 14.

The cross section of the main body 3 does not have to be circular, and may be, for example, a flat elliptical shape. Further, the core body 14 may not be included. Even if the cross section of the main body portion 3 is not circular and does not have the core body 14, the length L of the second portion 2d may be equal to or more than one turn of winding at the portion where the second portion 2d is arranged.

Thus, in the film capacitor B of Modification 2, the metal film 2 has the third portion 2e. And the 3rd part 2e where the effective region 13 is not connected to the external electrode 4 is arrange|positioned in the radial direction of the main-body part 3, and the length L in the circumferential direction is 1 round or more of winding. Since the effective region 13 of the third portion 2e is not connected to the external electrode 4, even if a voltage is applied to the film capacitor B, the electric field is not applied to the third portion 2e. Therefore, even if dielectric breakdown occurs in the wound layer around the third portion 2e, dielectric breakdown does not occur in the wound layer where the third portion 2e is located. Therefore, it is possible to suppress the dielectric breakdown that has occurred in the surrounding winding layer from spreading to the different winding layer beyond the third portion 2e, and it is possible to minimize the influence of the dielectric breakdown. The length L in the circumferential direction of the third portion 2e may be, for example, 1 to 2 turns of the winding, 1 to 1.5 turns of the winding, and further 1 turn of the winding. It may be up to 1.2 turns.

By setting L to be equal to or more than one turn of the winding, when the third portion 2e is arranged at a position where the distance (radius) from the center O of the winding is r, L becomes larger than 2πr and the radius r There is no portion on the circumference where the first portions 2c are adjacent to each other without the third portion 2e interposed therebetween. Therefore, when dielectric breakdown occurs, it is possible to prevent the dielectric breakdown from spreading to the surrounding layers. The third portion 2e is not electrically connected to the external electrode 4 and does not contribute to the capacitance of the film capacitor B. Therefore, the length L of the third portion 2e in the circumferential direction is preferably as small as possible within the range in which the effect can be exhibited.

The third portion 2e has a fourth groove 10 extending in the first direction (axial length direction, x direction) as shown in FIG. 10(a). The fourth groove 10 may be connected from one end (first end surface 1c) of the third portion 2e in the first direction (x direction) to the other end (second end surface 1d). By providing the fourth groove 10, even if a dielectric breakdown occurs in a portion adjacent to the third portion 2e of the first portion 2c, a gas generated when the metal film 2 is evaporated and scattered (hereinafter, simply referred to as gas). In some cases), the fourth groove 10 improves the self-healing property of the film capacitor B. That is, for example, even if dielectric breakdown occurs in the central portion in the axial direction (first direction, x direction) or in the vicinity of the insulating margin portion 6 and gas is generated, the fourth extending in the axial direction (x direction). Gas easily escapes to the external electrode 4 side through the groove 10 and the self-recovery property of the film capacitor B is improved.

The dielectric film 1 may be exposed at the bottom of the fourth groove 10 as shown in FIG. Further, as shown in FIG. 10C, the metal film 2 may be present at the bottom of the fourth groove 10 and the dielectric film 1 may not be exposed. That is, the bottom of the fourth groove 10 may be formed of the metal film 2 having a thickness smaller than that of the first portion 2c. That is, the z-direction depth of the fourth groove 10 may be smaller than the z-direction thickness of the metal film 2.

The third portion 2e may have only one fourth groove 10 or may have a plurality of fourth grooves 10. 10 to 12, the case where the third fourth groove 10 is provided is described, but the number of the fourth grooves 10 may be 1 to 2, or 4 or more.

FIG. 14 is an enlarged plan view of the one-dot chain line portion of FIG. The third portion 2e is electrically insulated from the external electrode 4 by the fifth groove 11, for example, as shown in FIG. The fifth groove 11 extends along the second direction (the winding circumferential direction, the y direction). Although the case where two fifth grooves 11 are provided is described in FIG. 14A, the number of fifth grooves 11 may be one, or may be three or more. From the viewpoint of surely insulating the third portion 2e from the external electrode 4, the number of the fifth grooves 11 is preferably set to 2-3.

Further, as shown in FIG. 14B, the film 5 with a metal film has an end opposite to the insulation margin portion 6 in the first direction (axial length direction, x direction) in the region where the third portion 2e exists. The portion (on the side of the first end surface 1c) may have a portion where the dielectric film 1 is exposed. That is, the film 5 with a metal film may have insulating margin portions 6 at both ends in the first direction (axial length direction, x direction) in the region where the third portion 2e exists.

The fourth groove 10 and the sixth groove 12 extend in the width direction (x direction), but may form a predetermined angle with the width direction (x direction). For example, the angle may be within ±45° with the x direction.

At least one third portion 2e is preferably arranged at a position where the distance r from the center O is smaller than 1/2 of the distance R from the center O to the outer periphery of the main body 3. On the inner circumference side of the winding, the pressure applied to the film 5 with a metal film is higher than on the outer circumference side, and the self-recovery property is lower than on the outer circumference side. Therefore, by arranging the third portion 2e at the inner peripheral side, that is, at the position of the distance r smaller than 1/2 of the distance R, the effect of further improving the self-recovery property can be obtained. The cross section of the main body 3 does not have to be a circle, and even when the cross section has an elliptical shape, for example, the distance R from the center O of the cross section to the outer periphery and the distance r from the center O on the same straight line as OR. The relationship may be the above-mentioned relationship.

Further, as shown in FIG. 13B, a plurality of third portions 2e, 2e' may be arranged at different radial positions r, r'of the body portion 3, respectively. The plurality of third parts 2e may be arranged at equal intervals in the radial direction of the main body 3. By providing the plurality of third portions 2e at different radial positions, the gas generated by the dielectric breakdown is more likely to escape.

The widths of the fourth groove 10, the fifth groove 11, and the sixth groove 12 may be in the range of 0.01 to 0.20 mm. By setting the width of the fourth groove 10 to be 0.01 to 0.20 mm, it is possible to secure the gas escape property. By setting the width of the fifth groove 11 to 0.01 to 0.20 mm, it is possible to suppress discharge between the effective region 13 of the third portion 2e and the region connected to the external electrode 4. By setting the width of the sixth groove 12 to be 0.01 to 0.20 mm, it is possible to suppress discharge between the first portion 2c and the third portion 2e.

In Modification 2, the effect can be obtained even when the film 5 with a metal film that does not have the second portion 2d is used. That is, in the film capacitor B using the film 5 with a metal film which does not have the first groove 7 and has the first portion 2c and the third portion 2e, the metal film 2 is a metal film including only the first portion 2c. The self-healing property is also improved for the film capacitor B using the attached film 5.

Further, 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) (see FIG. 3. Hereinafter, the outside of the metal film 2) The vicinity of the connection portion with the electrode 4 may be referred to as a heavy edge portion (HE)). 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 where the first portions 2c of the metal films 2a and 2b overlap each other. In other words, the heavy edge structure refers to a structure in which the metal film 2 in the heavy edge portion (HE) is thicker than the metal film 2 in the effective region.

In the effective region, the thickness of the metal film 2 is, for example, 20 nm or less, and preferably 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. In addition, the thickness of the metal film 2 in the vicinity of the connection portion with the external electrode 4 (heavy edge portion) is preferably 2 to 4 times the effective area, that is, 10 to 80 nm.

As shown in FIGS. 1, 2, 4, 5 and the like, both of the metal films 2a, 2b preferably have the structure shown in FIGS.

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), polyphenylene ether (PPE). ), polyetherimide (PEI), and cycloolefin polymer (COP). Particularly, polyarylate (PAR) is preferable because it has a high dielectric breakdown voltage.

Such film capacitors A and B may be manufactured as follows, for example. First, the dielectric film 1 is prepared. The dielectric film 1 is obtained, for example, by 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. As the solvent used for molding, 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, it is preferable to use an organic solvent containing a mixture of two or more selected from these. A resin film produced by the melt extrusion method may be stretched.

The thickness of the dielectric film 1 may be, for example, 5 μm or less, and it is particularly preferable to use the dielectric film 1 having a thickness of 0.5 to 4 μm.

The dielectric film 1 may be composed of only the above-mentioned insulating resin, but may contain other materials. Examples of the constituents other than the resin contained 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 surface treatment such as silane coupling treatment and titanate coupling treatment.

When such an inorganic filler is used for the dielectric film 1, by using a composite film containing less than 50% by mass of the inorganic filler and 50% by mass or more of the resin, the inorganic filler can be used while maintaining the flexibility 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 is preferably 4 to 1000 nm.

A metal component such as aluminum (Al) is vapor-deposited on one surface of the produced dielectric film 1 to form a metal film 2 to obtain a film 5 with a metal film.

In the case of forming a heavy edge structure, a portion other than the portion forming the heavy edge of the film 5 with a metal film is masked, and zinc (Zn), for example, is further deposited on the portion of the vapor-deposited metal component having no mask. It is formed by vapor deposition. At this time, the thickness of the film deposited as a heavy edge is 1 to 3 times the thickness of the above-described deposited metal component.

The metal film 2 is formed with the first groove 7 and, if necessary, the second groove 8 to the sixth groove 12. For forming each groove, a laser marker machine or a laser trimmer machine capable of flying 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.

The film 5 (5a, 5b) with a metal film having the metal film 2 (2a, 2b) on one surface is a set of two films, and as shown in FIGS. 1 and 2, slightly in the width direction (x direction). The main body 3 is obtained by stacking or winding in a shifted state.

Film capacitors A and B are obtained by forming metallikon electrodes as the external electrodes 4 on both end surfaces of the obtained main body 3. For forming the external electrode 4, for example, metal spraying, sputtering, plating, or the like is suitable.

Then, if necessary, the surface of the main body 3 having the external electrodes 4 formed thereon can 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), alloys, and the like.

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

FIG. 15 is a perspective view schematically showing the configuration of one embodiment of the linked capacitor. In FIG. 15, the case and the resin for molding are omitted in order to make the configuration easy to understand. The connection type capacitor C of this embodiment has a structure in which a plurality of film capacitors B are connected in parallel by a pair of bus bars 21 and 23. The bus bars 21 and 23 are composed of external connection terminal portions 21a and 23a and lead-out terminal portions 21b and 23b connected to the external electrodes 4a and 4b of the film capacitor B, respectively.

When the film capacitor B described above is applied to the connection type capacitor C, the connection type capacitor C having excellent self-recovery property can be obtained.

In the connection type capacitor C, a plurality of film capacitors B (four in the present embodiment) are arranged side by side to the external electrodes 4a and 4b respectively formed at both ends of the main body portion 3 via the bonding material and the bus bar 21. , 23 can be obtained.

The film capacitors A and B and the connection type capacitor C may be housed in a case and then filled with a resin in a space inside the case to be a resin mold type (case mold type) capacitor.

In addition, in the concatenated capacitor C shown in FIG. 15, the film capacitor B having an elliptical cross section is arranged in the direction of the major axis of the cross section. In addition to this, the film capacitor B is arranged in the direction of the minor axis of the cross section. Similar effects can be obtained even with a stacked structure. Further, although the linked capacitor C shown in FIG. 15 is arranged horizontally in the axial direction (x direction), it may be arranged vertically in the axial direction (x direction). Further, although the connection type capacitor C using the film capacitor B is shown in FIG. 15, it goes without saying that a laminated film capacitor A may be used instead of the film capacitor B.

FIG. 16 is a schematic configuration diagram for explaining the configuration of one embodiment of the inverter. FIG. 16 shows an example of an inverter D that produces alternating current from direct current. As shown in FIG. 16, 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. Here, the film capacitor A, the film capacitor B, or the connection type capacitor C described above is applied as the capacitance unit 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.

FIG. 17 is a schematic configuration diagram showing an embodiment of an electric vehicle. FIG. 17 shows an example of a hybrid vehicle (HEV) as the electric vehicle E.

In FIG. 17, reference numeral 41 is a driving motor, 43 is an engine, 45 is a transmission, 47 is an inverter, 49 is a power source (battery), and 51a and 51b are front wheels and rear wheels.

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

Further, the electric vehicle E shown in FIG. 17 is provided with a vehicle ECU 53 that performs overall control of the electric vehicle E as a whole. To the vehicle ECU 53, a drive signal corresponding to an operation of a driver or the like from the electric vehicle E, such as an ignition key 55, an accelerator pedal (not shown), and a brake, is input. The vehicle ECU 53 outputs an instruction signal based on the drive signal to the engine ECU 57, the power supply 49, and the 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.

When the inverter D to which the film capacitor A, the film capacitor B or the connection type capacitor C of the present embodiment is applied as the capacitance section 33 is mounted on, for example, an electric vehicle E as shown in FIG. 17, the film capacitor A, the film capacitor B or Since the coupling type capacitor C has excellent self-healing property, the capacitance 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.

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. ..

A dielectric film having an average thickness of 3 μm was produced using polyarylate (U-100, manufactured by Unitika Ltd.). The dielectric film was prepared by dissolving polyarylate in toluene, applying it on a substrate made of polyethylene terephthalate (PET) using a coater, and molding it 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 from the substrate and slitted to a width of 130 mm, and then an Al metal film was formed as a metal film on one surface of the dielectric film by a vacuum deposition method. At this time, the sample No. Samples Nos. 1 to 5 each had a 97 mm width Al metal film formed using a metal mask. In Nos. 6 to 9, an Al metal film was formed on the entire surface of one surface.

Sample No. In Nos. 2 to 5, the first groove and the second groove were formed in the vicinity of the end portion in the width direction of the metal film by using the green laser marker. Sample No. In Nos. 6 to 9, the first groove, the second groove, and the third groove were formed near the center in the width direction of the metal film by using the 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 produced film with a metal film having a width of 130 mm was further slitted to obtain a film with a metal film having a width of 50 mm (Sample Nos. 2 to 9) having a first groove, a second groove and a third groove. Table 1 shows the arrangement of the first groove, the second groove, and the third groove (W1, W3, the number of the second and third grooves, and the pitch p). Sample No. As for 1, the first groove, the second groove, and the third groove were not formed, the second portion 2d was not formed, and an insulation margin portion of 1.5 mm (metal in which the dielectric film was exposed) was formed. It has a film non-formation part).

Sample No. Sample Nos. 10 and 11 are sample Nos. Using a green laser marker, a fourth groove, a fifth groove, and a sixth groove were formed on a dielectric film on which a metal film similar to that of 1 was formed at predetermined positions in the length direction. , A third part is provided. The laser irradiation conditions were an output of 4 W, a frequency of 140 kHz, and a scan speed of 4 m/sec. In the third part, the interval (L) in the lengthwise direction of the sixth groove was 36 mm, and the five fourth grooves were arranged at equal intervals (6 mm interval) therebetween. Further, two fifth grooves are arranged at 0.5 mm intervals on both sides of the center of an Al metal film having a width of 97 mm, and two films with metal films shown in FIG. A state was produced in which the left end of a) was connected in a mirror-symmetrical state with the left end as the axis of symmetry.

The produced film with a metal film having a width of 130 mm is further slit-processed to have a 1.5 mm insulating margin portion (a metal film non-forming portion where the dielectric film is exposed) and a fourth groove and a sixth groove extending in the width direction. And a metal film with a metal film having a width of 50 mm and a length of 20 m, which has a fifth groove in the vicinity of connection with an external electrode, that is, a film with a metal film having a third portion in the length direction. Sample No. No. 12 is a comparative example, and the third part was not provided.

The slipperiness of the film with a metal film was measured according to Sample No. It confirmed by measuring the static friction coefficient of the film with a metal film of 1, 6-9. When the coefficient of static friction of the film with a metal film was less than 0.6, it was judged that the slip property was good, and when it was 0.6 or more, the slip property was judged to be poor. The results are shown in Table 1.

As the winding core, a cylinder made of polyphenylene sulfide (PPS) having an outer diameter of 5 mm and a length of 50 mm was used. A pair of films with a metal film having a width of 50 mm were superposed so that the metal films face each other with the dielectric film interposed therebetween, and wound on a winding core to prepare a wound body. In addition, the pair of films with a metal film are shifted from each other by 0.5 mm in the width direction (x direction), and the second portion 2d or the insulating margin portion is arranged on each side different in the width direction (x direction). It was wound to obtain a wound body (main body). Sample No. The number of turns of 1 to 9 was 50 times. Sample No. Nos. 10 and 11 were adjusted so that the third part was located at the position (r) shown in Table 2.

An alloy of zinc and tin was sprayed on the opposite end surfaces of the wound body (main body) where the metal film was exposed, 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 the voltage at which 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 was performed using an insulation resistance tester.

Sample No. In Nos. 2 to 11, there was little decrease in insulation resistance before and after the withstand voltage test, and the self-healing property was excellent. In addition, the sample No. Nos. 6 to 9 had good slipperiness. On the other hand, sample No. Sample No. 1 had low slipperiness, the insulation resistance significantly decreased after the withstanding voltage test, and the self-healing property did not function sufficiently. Sample No. No. 12 had a large decrease in insulation resistance after the withstand voltage test, and the self-healing property did not function sufficiently.

A: laminated film capacitor B: wound film capacitor C: connection type capacitor D: inverter E: electric vehicle 1, 1a, 1b: dielectric film 2, 2a, 2b: metal film 2c: first portion of metal film 2d: second part of metal film 3: body parts 4, 4a, 4b: external electrodes 5, 5a, 5b: film with metal film 6: insulating margin part 7: first groove 8: second groove 9: second 3 groove 10: 4th groove 11: 5th groove 12: 6th groove 13: Effective area 14: Core bodies 21, 23: Bus bar 31: Bridge circuit 33: Capacitance part 35: Boost 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 (14)

A metal film provided with a main body that is a wound body that is wound a plurality of times, and external electrodes that are respectively provided at a pair of main body end portions located in the axial direction of the main body,
The film with a metal film includes a rectangular dielectric film and a metal film arranged on one surface of the dielectric film,
The dielectric film has a first end surface located on one side in the first direction of the dielectric film and a second end surface located on the other side,
The metal film has a first portion arranged on the first end surface side of the dielectric film and a second portion arranged on the second end surface side of the dielectric film,
The first portion and the second portion are separated from each other by a first groove for degassing that extends in a second direction orthogonal to the first direction of the dielectric film,
The main body portion has an effective region in which electrostatic capacitance is expressed by the first portion being connected to the external electrode at one of the main body end portions,
The metal film has a third portion, and the third portion is formed by a sixth groove for degassing that extends from one end to the other end in the axial direction in the effective region. While being separated from the part, not electrically connected to any of the pair of external electrodes, the length of the third part in the second direction is equal to or greater than one turn of winding,
A film capacitor having at least one third portion at a position where the distance from the center of winding of the main body is smaller than 1/2 of the distance from the center to the outer periphery. When the length of the dielectric film in the first direction is W1 and the distance between the second end face and the first groove is W2, the ratio of W2 to W1 (W2/W1) is 0.23 or less. The film capacitor according to claim 1, wherein The film capacitor according to claim 2, wherein the W2 is 0.5 to 2.0 mm. An end surface of the first portion on the side of the first end surface is located on a first end surface of the dielectric film,
The film capacitor according to claim 1, wherein an end surface of the second portion on the second end surface side is located on a second end surface of the dielectric film. The film capacitor according to claim 1, wherein the second portion has a plurality of divided portions. The film capacitor according to claim 5, wherein the second portion has a second groove extending in the second direction. The film capacitor according to claim 5, wherein the second portion has a third groove extending in the first direction. The film capacitor according to claim 1, wherein the third portion has a fourth groove extending in the axial direction and located between the sixth grooves . The film capacitor according to claim 1, wherein the third portion has a fifth groove extending along the second direction. The film capacitor according to claim 1, wherein a plurality of the third parts are provided, and the plurality of the third parts are respectively arranged at positions different in distance from the center of the winding. A connection-type capacitor, comprising: a plurality of film capacitors; and a bus bar connecting the plurality of film capacitors, wherein the film capacitor is the film capacitor according to any one of claims 1 to 10. An inverter comprising a bridge circuit constituted by a switching element and a capacitance section connected to the bridge circuit, wherein the capacitance section is the film capacitor according to any one of claims 1 to 10. An inverter comprising a bridge circuit formed of switching elements and a capacitance section connected to the bridge circuit, wherein the capacitance section is the concatenated capacitor according to claim 11. An electric vehicle comprising a power supply, the inverter according to claim 12 or 13 connected to the power supply, a motor connected to the inverter, and wheels driven by the motor.

Images