JP6913856B2 - Film capacitor - Google Patents

Description

The present invention relates to a film capacitor used in various electronic devices, electric devices, industrial devices, electrical components of automobiles, and the like.

In recent years, from the viewpoint of environmental protection, all electric devices are controlled by an inverter circuit, and energy saving and high efficiency are being promoted. In particular, in the automobile industry, the development of technologies related to global environment-friendly energy saving and high efficiency is becoming active, such as the introduction of hybrid electric vehicles (hereinafter referred to as HEVs) that run on electric motors and engines.

Since such an electric motor for HEV has a high working voltage range of several hundred volts, a film capacitor having a high withstand voltage and low loss electrical characteristics is attracting attention as a capacitor used in connection with such an electric motor. Has been done. In addition, there is a conspicuous tendency to use film capacitors, which have an extremely long life, due to the demand for maintenance-free products in the market.

Film capacitors are generally classified into those using a metal foil as an electrode and those using a vapor-deposited metal provided on a dielectric film as an electrode. Among them, a film capacitor using a so-called metallized film in which a vapor-deposited metal is provided on a dielectric film has a smaller volume occupied by the electrode and can be made smaller and lighter than a capacitor using a metal foil. High reliability against dielectric breakdown due to recovery performance (performance in which when a short circuit occurs in an insulation defect, the vaporized electrode around the defect evaporates and scatters due to the energy of the short circuit to insulate and restore the function of the capacitor). , Has been widely used in the past.

Among them, for example, as described in Patent Document 1, a film capacitor has been proposed in which a plurality of capacitor elements are grouped together to substantially reduce the size. FIG. 7 shows a cross-sectional view of this type of film capacitor. In the film capacitor 6 of FIG. 7, two capacitor elements are grouped together by making the winding shaft coaxial.

As shown in FIG. 7, in the film capacitor 6, an inner winding element 61 formed by winding a metallized film around a winding shaft D, and an inner winding element 61 outside the inner winding element 61. An outer winding element 64 formed by winding a metallized film having the same width as the metallized film forming the winding element 61 is formed via an insulating material 67. The metallikon electrode 62b formed on one end face (lower side in FIG. 7) of the two winding elements and the metallikon electrode 65b are integrated, and the other end face of the two winding elements has a metallikon, respectively. The electrode 62a and the metallikon electrode 65a are formed, and the capacitor element 63 and the capacitor element 66, which have the same dimensions in the winding axis direction, constitute a film capacitor.

According to such a film capacitor in which a plurality of capacitor elements are grouped together, the mounting space (area, volume) is reduced and substantially, as compared with the case where the plurality of capacitor elements are used as separate single capacitors. In addition, the film capacitor can be miniaturized.

Jikkai Sho 55-173132

However, in a film capacitor having a configuration as shown in FIG. 7 in which a plurality of capacitor elements are grouped together, the capacitor can be substantially reduced in size, but the surface area per capacity of the film capacitor is reduced, so that when the capacitor is in operation. There was a problem that it became difficult for the heat of the film to dissipate and the temperature rise became large.

In order to solve such a problem, the film capacitor of the present invention is a film capacitor provided with a wound body in which a metallized film having a metal electrode provided on the surface of a dielectric film is wound, and the wound body is provided. Consists of a plurality of capacitor elements having the same winding axis, and the plurality of capacitor elements include two or more capacitor elements having different dimensions in the winding axis direction.

As described above, in a film capacitor in which a plurality of capacitor elements are grouped together to substantially reduce the size of the capacitor, the film capacitor can be operated by different dimensions in the winding axis direction of the plurality of capacitor elements. The heat of time is easily dissipated, the temperature rise of the film capacitor can be suppressed, and the life and reliability can be improved.

The perspective view of the film capacitor in Embodiment 1 of this invention. FIG. 5 is a cross-sectional view of the film capacitor according to the first embodiment of the present invention. The perspective view of the film capacitor in Embodiment 2 of this invention. FIG. 2 is a cross-sectional view of a film capacitor according to a second embodiment of the present invention. FIG. 3 is a cross-sectional view of a film capacitor according to a third embodiment of the present invention. The perspective view of the film capacitor in Embodiment 4 of this invention. Sectional view of a conventional film capacitor.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments.

(Embodiment 1)
FIG. 1 is a perspective view showing the appearance of the film capacitor according to the first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the film capacitor shown in FIG.

As shown in FIG. 1, in the film capacitor 1 of the present embodiment, a winding element 11 formed by winding a metallized film and a metallikon electrode 12a formed on an end surface of the winding element 11 are formed. It has a capacitor element 13 and a winding element 14 formed by winding a metallized film on the outside of the capacitor element 13, and a metallikon electrode 15a formed on an end surface of the winding element 14. The capacitor element 16 includes two capacitor elements, and includes a winding body 10 in which the two capacitor elements are agglomerated.

External terminals 19a, 19b, 19c for connecting the film capacitor 1 and an external device are connected to the metallikon electrodes 12a, 15a, 15b of the film capacitor 1.

Explaining in detail with reference to FIG. 2, among the two capacitor elements 13 and 16 constituting the winding body 10, the capacitor element 13 is made of aluminum, aluminum, etc. on the surface of a dielectric film such as polypropylene or polyethylene terephthalate. A winding element 11 formed by winding a metallized film on which a metal vapor deposition electrode such as a metal alloy of the above is formed around a winding shaft (line A in FIG. 2), and both ends of the winding element 11. It has metallic capacitors 12a and 12b formed on the surface.

The capacitor element 16 is a metallized film having a dimension in the winding axis direction smaller than that of the metallized film forming the winding element 11 via an insulating material 17 such as polypropylene or polyethylene terephthalate on the outside of the winding element 11. It has a winding element 14 formed by winding a winding element 14 and metallised electrodes 15a and 15b formed on both end faces of the winding element 14.

Here, the metallikon electrode 12b of the capacitor element 13 and the metallikon electrode 15b of the capacitor element 16 are integrated. That is, the capacitor element 13 and the capacitor element 16 share one electrode, and when the external terminal 19c is connected to the metallikon electrode 15b as described above, the capacitor element 13 is also electrically connected to the external device. It will be.

The capacitor element 13 and the capacitor element 16 formed of a metallized film having different dimensions in the winding axis direction have different dimensions in the winding axis direction, and the dimensions in the winding axis direction of the capacitor element 16 are the capacitor elements. It is smaller than the dimension in the winding axis direction of 13, and therefore, a part of the capacitor element 13 protrudes from the end surface of the capacitor element 16 (the end surface on the metallised electrode 15a side in FIG. 2).

In this way, in the film capacitor 1 in which the winding axes of the two capacitor elements 13 and 16 are the same and the two capacitor elements 13 and 16 are grouped together, a part of one capacitor element 13 is a part of the other capacitor element. By protruding from the end face of 16, the area of the portion exposed to the outside of one of the capacitor elements 13 becomes large, and as a result, the heat generated by the self-heating during the operation of the film capacitor 1 becomes easy to dissipate. It is possible to suppress the temperature rise of the film capacitor.

In the present embodiment, the description has been made based on the configuration of the film capacitor 1 including two capacitor elements, the capacitor element 13 and the capacitor element 16, but the number of capacitor elements is not limited to this. As shown in 6, three capacitor elements of the capacitor element 43, the capacitor element 46, and the capacitor element 53 may be provided, or a larger number of capacitor elements may be provided.

Further, by arranging the capacitor element having the highest operating temperature among the plurality of capacitor elements on the outermost periphery of the winding body, at least the outer surface of the capacitor element is exposed to the outside of the film capacitor 1. Therefore, the temperature rise due to self-heating during operation of the film capacitor can be further reduced.

In this case, by making the temperature during operation of the capacitor element decrease from the outermost circumference to the innermost circumference, the temperature rise due to self-heating during operation of the film capacitor can be further reduced. For example, when two capacitor elements, a smoothing capacitor element and a filter capacitor element mounted on an inverter circuit of a hybrid vehicle, are made into a single film capacitor according to the configuration of the present invention, the temperature rises to the outer peripheral side. It is preferable to arrange a capacitor element for a filter having a large size in order to suppress a temperature rise of the film capacitor.

Further, the strength of the film capacitor can be increased by arranging the capacitor element having the largest dimension in the winding axis direction among the plurality of capacitor elements near the winding axis of the winding body.

(Embodiment 2)
FIG. 3 is a perspective view showing the appearance of the film capacitor according to the second embodiment of the present invention.

FIG. 4 is a cross-sectional view of the film capacitor shown in FIG.

As shown in FIG. 3, the film capacitor 2 in the present embodiment has a winding element 21 formed by winding a metallized film and a metallikon electrode 22a formed on an end surface of the winding element 21. It has a capacitor element 23, a winding element 24 formed by winding a metallized film on the outside of the capacitor element 23, and a metallikon electrode 25a formed on an end surface of the winding element 24. The capacitor element 26 includes two capacitor elements, and includes a winding body 20 in which the two capacitor elements are agglomerated.

External terminals 29a, 29b, 29c for connecting the film capacitor 2 and an external device are connected to the metallikon electrodes 22a, 25a, 25b of the film capacitor 2.

Explaining in detail with reference to FIG. 4, of the two capacitor elements 23 and 26 constituting the winding body 20, the capacitor element 23 has a metallized film centered on a winding shaft (line B1 in FIG. 4). It has a winding element 21 formed by winding and metallicon electrodes 22a and 22b formed on both end faces of the winding element 21.

The capacitor element 26 is formed by winding a metallized film having a dimension in the winding axis direction smaller than that of the metallized film forming the winding element 21 on the outside of the winding element 21 via an insulating material 27. It has a winding element 24 and metallised electrodes 25a and 25b formed on both end faces of the winding element 24.

Here, the metallikon electrode 22b of the capacitor element 23 and the metallikon electrode 25b of the capacitor element 26 are integrated. That is, the capacitor element 23 and the capacitor element 26 share one electrode, and when the external terminal 29c is connected to the metallikon electrode 25b as described above, the capacitor element 23 is also electrically connected to the external device. It will be.

The dimension of the capacitor element 26 in the winding axis direction is smaller than the dimension of the capacitor element 23 in the winding axis direction, and a part of the capacitor element 23 protrudes from the end face of the capacitor element 26.

Then, a heat transfer material 28 is provided on the outside of the insulating material 27 between the capacitor element 23 and the capacitor element 26, and a part of the heat transfer material 28 is wound among the two capacitor elements 23 and 26. It protrudes from the end face of the capacitor element 26 having a small axial dimension and is sandwiched so as to be exposed to the outside.

The heat transfer material 28 has a higher thermal conductivity than the dielectric film constituting the film capacitor such as a metal foil such as copper foil or aluminum foil or a graphite sheet, or polypropylene or polyethylene terephthalate used as a material such as an insulating material 27. Selected from expensive materials.

In this way, in the film capacitor 2 provided with the winding body 20 in which the two capacitor elements 23 and 26 are agglomerated, the heat transfer material 28 having a high thermal conductivity is sandwiched between the two capacitor elements 23 and 26. By placing a part of the heat transfer material 28 so as to protrude from the end face of the capacitor element 26 having a small dimension in the winding axis direction, the inside of the film capacitor 2 generated by self-heating during operation of the film capacitor 2 The heat of the film capacitor 2 can be easily dissipated to the outside of the film capacitor 2, and as a result, the temperature rise inside the film capacitor 2 can be suppressed.

The heat transfer material 28 is either the central portion of the capacitor element 23 in the winding axis direction (line B2 in FIG. 4) or the central portion of the capacitor element 26 in the winding axis direction (line B3 in FIG. 4). It is preferable that it reaches the center of the wall. With such a configuration, more heat at the center of the capacitor elements 23 and 26, which has the highest operating temperature of the capacitor elements 23 and 26, can be dissipated to the outside of the capacitor elements 23 and 26. As a result, the temperature rise of the film capacitor 2 can be further suppressed.

Further, in the case of the configuration of the film capacitor 2, the heat generated inside the capacitor element 26 can be drawn out to the outside through the heat transfer material 28 and dissipated. Therefore, as the capacitor element 26 on the outer peripheral side, it is better to arrange a capacitor element that wants to dissipate heat to the outside, that is, a capacitor element that has a higher operating temperature, so that the temperature rise of the film capacitor 2 as a whole can be suppressed. Can be done.

(Embodiment 3)
FIG. 5 is a cross-sectional view of the film capacitor according to the third embodiment of the present invention.

As shown in FIG. 5, the film capacitor 3 in the present embodiment includes a winding element 31 formed by winding a metallized film, and a metallikon electrode 32a formed on an end surface of the winding element 31. A capacitor element 33 having a capacitor element 33, a winding element 34 formed by winding a metallized film on the outside of the capacitor element 33, and a metallikon electrode 35a formed on an end surface of the winding element 34. Including two capacitor elements of the capacitor element 36 having the above, the winding body in which these two capacitor elements are integrated is provided.

More specifically, among the two capacitor elements constituting the winding body, the capacitor element 33 is a winding element formed by winding a metallized film around a winding shaft (line C1 in FIG. 5). It has 31 and metallicon electrodes 32a and 32b formed on both end faces of the winding element 31.

The capacitor element 36 is formed by winding a metallized film having a dimension in the winding axis direction smaller than that of the metallized film forming the winding element 31 on the outside of the winding element 31 via an insulating material 37. It has a winding element 34 and metallicon electrodes 35a and 35b formed on both end faces of the winding element 34.

The dimension of the capacitor element 36 in the winding axis direction is smaller than the dimension of the capacitor element 33 in the winding axis direction, and a part of the capacitor element 33 protrudes from both end faces of the capacitor element 36.

The heat transfer material 38a and the heat transfer material 38b are sandwiched between the capacitor element 33 and the capacitor element 36 on the outside of the insulating material 37. The heat transfer material 38a and the heat transfer material 38b are not electrically connected to each other, and are arranged in a non-contact state at intervals inside the capacitor element 36 as shown in FIG.

The heat transfer material 38a protrudes from one of the end faces (upper side in FIG. 5) of the capacitor element 36 having a smaller dimension in the winding axis direction among the two capacitor elements 33 and 36, and the heat transfer material 38b is the two capacitors. Among the elements 33 and 36, the capacitor element 36 having a small dimension in the winding axis direction protrudes from the other end surface (lower side in FIG. 5).

It is preferable that either the heat transfer material 38a or the heat transfer material 38b reaches the central portion (line C2 in FIG. 5) of the capacitor element 33 or the capacitor element 36 in the winding axis direction. In the present embodiment, the heat transfer material 38a reaches the central portion in the winding axis direction.

In this way, in a film capacitor having a winding body in which two capacitor elements 33 and 36 are agglomerated, a part of the capacitor element 36 protrudes from both end faces of the capacitor element 33. By configuring the heat transfer material 38a to protrude from both end faces of the capacitor element 36, it is possible to suppress the temperature rise of the film capacitor 3 and also suppress the temperature bias in the winding axis direction of the film capacitor 3. be able to.

The balance of the amount (dimensions) of a part of the capacitor element 36 protruding from one end face and the other end face of the capacitor element 33 depends on the dimensions of the two heat transfer materials 38a and 38b in the winding axis direction. It may be controlled so that the temperature deviation in the winding axis direction of the film capacitor 3 becomes small in combination with the sandwiching position and the like.

In the present embodiment, the configuration in which the heat transfer material 38a and the heat transfer material 38b are sandwiched between the capacitor element 33 and the capacitor element 36 has been described, but from both end faces of the capacitor element 33, the capacitor element In a configuration in which a part of the capacitor element 36 is projected, when the heat transfer material 38a and the heat transfer material 38b are not sandwiched between the capacitor element 33 and the capacitor element 36, a part of the capacitor element 36 is a capacitor element. It is preferable that the amount (dimension) protruding from one end face of 33 and the other end face is uniform on both end faces of the capacitor element 33 because the temperature deviation in the winding axis direction of the film capacitor 3 can be made smaller. ..

The present invention is useful for film capacitors used in various electronic devices, electrical devices, industrial devices, electrical components of automobiles, and the like.

1, 2, 3 Film capacitors 10, 20, 30 Winders 11, 21, 31 Winding elements 12a, 12b, 22a, 22b, 32a, 32b Metallicon electrodes 13, 16, 23, 26, 33, 36, 43, 46, 53 Capacitor elements 14, 24, 34 Winding elements 15a, 15b, 25a, 25b, 35a, 35b Metallicon electrodes 17, 27, 37 Insulating materials 19a, 19b, 19c, 29a, 29b, 29c External terminals 28, 38a, 38b Heat transfer material

Claims (4)

A film capacitor having a wound body in which a metallized film having a metal electrode provided on the surface of a dielectric film is wound.
The winding body is composed of a plurality of capacitor elements having the same winding axis.
Wherein the plurality of capacitor elements are disposed adjacent, it viewed including the dimensions of the winding axis directions are different two capacitor elements,
Both end faces of the capacitor element having a large dimension in the winding axis direction of the two capacitor elements project in the winding axis direction from both end faces of the capacitor element having a small dimension in the winding axis direction.
Two heat transfer materials spaced apart in the winding axis direction are sandwiched between the two capacitor elements, and the two heat transfer materials are in the winding axis direction of the two capacitor elements. A film capacitor characterized in that it protrudes in the winding axis direction from both end faces of a capacitor element having a small size. The film capacitor according to claim 1, wherein the capacitor element having the highest operating temperature among the plurality of capacitor elements is arranged on the outermost circumference of the winding body. The film capacitor according to claim 1, wherein the capacitor element having the largest dimension in the winding axis direction among the plurality of capacitor elements is arranged closer to the winding axis of the winding body. The film capacitor according to claim 2, wherein the outermost capacitor element of the winding body is used for a filter circuit.

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