Capacitor

Abstract

A capacitor includes a plurality of capacitor elements, a casing that houses the plurality of capacitor elements, and a filling resin with which the casing is filled. The casing includes a bottom wall having an opening portion at a center of the bottom wall, an inner peripheral wall having a tubular shape and rising from an outer peripheral edge of the opening portion, and an outer peripheral wall having a tubular shape and rising from an outer peripheral edge of the bottom wall. The plurality of capacitor elements are arranged in the casing to surround the opening portion.

Description

Technical area

[0001] The present disclosure relates to a capacitor. background

[0002] In the related art, a molded capacitor is known in which a plurality of capacitor elements are housed in a case, and the case is filled with a filler resin (see, for example, PTL 1). In the case, the plurality of capacitor elements are arranged in a row or in a matrix.

[0003] In recent years, hybrid vehicles and electric vehicles have become more common, and in these vehicles, the capacitor is incorporated into an inverter unit for driving an electric motor. The inverter unit includes an inverter that converts DC power supplied by a battery into AC power, and a housing that houses the inverter and capacitor. It is separate from a bracket to which the electric motor is attached and is located near the electric motor. List of cited documentsPatent literature

[0004] PTL 1: International Publication WO 2020 / 031676 Summary

[0005] A main aspect of the present disclosure relates to a capacitor. A capacitor according to the present aspect includes a plurality of capacitor elements, a casing accommodating the plurality of capacitor elements, and a filling resin with which the casing is filled. Here, the casing includes a bottom wall having an opening portion at a center of the bottom wall, an inner peripheral wall having a tubular shape and rising from an outer peripheral edge of the opening portion, and an outer peripheral wall having a tubular shape and rising from an outer peripheral edge of the bottom wall. The plurality of capacitor elements are arranged in the casing so as to surround the opening portion.

[0006] According to the present disclosure, it is possible to provide a capacitor in which a plurality of capacitor elements can be arranged to surround a predetermined object included in a device in which the capacitor is incorporated.

[0007] The effect or significance of the present disclosure will become clearer from an embodiment described below. However, it should be noted that the embodiment described below is merely an example of implementing the present disclosure in all aspects, and therefore the present disclosure is not limited to the following embodiment. Brief description of the drawings Fig. 1A is a perspective view showing a film capacitor according to an exemplary embodiment. Fig. 1B is a perspective view showing the film capacitor in a state where it is not filled with a filling resin according to the exemplary embodiment. Fig. 2A is a perspective view showing a capacitor element unit according to the exemplary embodiment. Fig. 2B is a perspective view showing the capacitor element unit according to the exemplary embodiment. Fig. 3A is a perspective view showing a first bus bar of the exemplary embodiment. Fig. 3B is a perspective view showing a second bus bar of the exemplary embodiment. Fig. 4 is a perspective view showing housings according to the exemplary embodiment. Fig. 5 is a diagram showing a state in which the film capacitor and an electric motor according to the exemplary embodiment are attached to a bracket. Fig. 6 is a plan view showing a film capacitor in a state where it is not filled with a filling resin according to Modification 1. Fig. 7 is a plan view showing a film capacitor in a state where it is not filled with a filling resin according to Modification 2. Fig. 8 is a plan view showing a film capacitor in a state where it is not filled with a filling resin according to Modification 3. Fig. 9 is a plan view showing a film capacitor in a state where it is not filled with a filling resin according to Modification 4. Description of an embodiment

[0008] Before describing an embodiment, a problem of the prior art will be briefly described. To contribute to weight reduction and space savings in electric vehicles and the like, it is conceivable to install an inverter and a capacitor in a bracket to integrate an electric motor, the inverter, and the capacitor into a single motor unit.

[0009] At this time, in a state where the electric motor is installed in the electric vehicle or the like, a gap is relatively easily formed around a rotor shaft of the electric motor. Therefore, if the capacitor can be configured such that a plurality of capacitor elements are arranged to surround the rotor shaft, the space around the rotor shaft can be effectively utilized, and the motor unit can be made compact.

[0010] Not limited to the rotor shaft of the electric motor described above, in an external device in which a capacitor is incorporated, a compact structure of the external device can be expected if a plurality of capacitor elements can be arranged to surround a predetermined object included in the external device.

[0011] In view of this problem, the present disclosure provides a capacitor in which a plurality of capacitor elements can be arranged to surround a predetermined object included in a device in which the capacitor is incorporated.

[0012] A film capacitor, which is an exemplary embodiment of a capacitor of the present disclosure, will be described below with reference to the accompanying drawings. Note that, for convenience, in the following description, a direction in which a housing opens is a vertical direction.

[0013] Fig. 1A is a perspective view showing the film capacitor 1, and Fig. Fig. 1B is a perspective view showing the film capacitor 1 in a state where it is not filled with filling resin 600. The Fig. 2A and Fig. 2B are perspective views showing the capacitor element unit 10. Fig. 2A is a schematic diagram of the capacitor element unit 10, viewed from an end face 101 of the capacitor element 100, and Fig. 2B is a schematic diagram of the capacitor element unit 10 as viewed from another end face 102 of the capacitor element 100. Fig. 3A is a perspective view showing the first busbar 200, and Fig. 3B is a perspective view showing the second bus bar 300. Fig. 4 is a perspective view showing the housing 500.

[0014] The film capacitor 1 comprises three sets of capacitor elements 10, a housing 500 and filling resin 600.

[0015] Each capacitor element unit 10 comprises two capacitor elements 100, a first busbar 200, a second busbar 300 and an insulating layer 400.

[0016] Each capacitor element 100 is formed by overlapping two metallized foils formed by vapor deposition of aluminum onto a dielectric foil, winding or stacking the overlapped metallized foils, and pressing the metallized foils into a flat shape. The capacitor element 100 has a shape resembling a flat elliptical cylinder. That is, the capacitor element 100 has two end faces 101, 102 with a substantially elliptical shape (one semicircular section has a short straight section) and a circumferential surface 103 between the end face 101 and the end face 102.

[0017] The first electrode 110 is formed on one end face 101 by spraying a metal such as zinc, and the second electrode 120 is formed on another end face 102 by similarly spraying a metal such as zinc.

[0018] The peripheral surface 103 includes a pair of opposing flat surfaces 103a and a pair of curved surfaces 103b connecting the pair of flat surfaces 103a. The curved surface 103b has a short flat surface between the two arcuate surfaces. The curved surface 103b may include only an arcuate surface without a flat surface. The capacitor element 100 is elongated in a direction in which the pair of curved surfaces 103b are aligned.

[0019] The first bus bar 200 and the second bus bar 300 are formed into a predetermined shape by appropriate processing such as cutting and bending on a conductive material having a plate shape, for example, a copper plate.

[0020] The first busbar 200 has a plate shape with an L-shape that is long in the horizontal direction and short in the vertical direction. Two first electrode pins 210 are formed at a lower end of the first busbar 200 at a position close to one end face in the horizontal direction. In a thickness direction of the first busbar 200, two first electrode pins 210 each extend in opposite directions to each other.

[0021] The second busbar 300 has a plate shape with a rectangular shape elongated in the vertical direction. Two second electrode pins 310 are formed at a lower end of the second busbar 300 at a position close to one end face in the horizontal direction. In a thickness direction of the second busbar 300, two second electrode pins 310 each extend in opposite directions to each other.

[0022] The insulating layer 400 has a rectangular shape and is made of insulating paper or an electrically insulating resin material such as acrylic or silicone.

[0023] The first busbar 200 and the second busbar 300 overlap when viewed from their thickness direction. The upper end portion of the first busbar 200 and the upper end portion of the second busbar 300 are arranged at the same height and do not overlap when viewed from the thickness direction. The insulating layer 400 is bent in the center to cover a portion of the second busbar 300 that overlaps the first busbar 200. This ensures electrical insulation between the first busbar 200 and the second busbar 300.

[0024] The busbar unit 11 consists of a first busbar 200, a second busbar 300 and an insulating layer 400, wherein the first busbar 200 and the second busbar 300 overlap each other.

[0025] On both sides of the busbar assembly 11, two capacitor elements 100 are arranged such that curved surfaces 103b of their peripheral surfaces 103 face each other. Two adjacent capacitor elements 100 are not aligned along a straight line, but are arranged along a slightly curved line to conform to an internal shape of the housing 500.

[0026] Two first electrode pins 210 of the first busbar 200 contact first electrodes 110 of two capacitor elements 100 and are connected to the first electrodes 110 by a joining method such as soldering. Two second electrode pins 310 of the second busbar 300 contact second electrodes 120 of the two capacitor elements 100 and are connected to the second electrodes 120 by a joining method such as soldering. As a result, the two capacitor elements 100 are electrically connected to the first busbars 200 and the second busbars 300.

[0027] The insulating layer 400 also covers portions of the second busbar 300 that are close to the first electrode 110 of the two capacitor elements 100. This also ensures electrical insulation between the second busbar 300 and the two first electrodes 110.

[0028] The housing 500 is made of a plastic, for example, polyphenylene sulfide (PPS), a thermoplastic. The housing 500 is formed in the shape of a double cylindrical box with an open top surface and includes a bottom wall 502 having a disc shape and a circular opening portion 501 at a center of the bottom wall 502, an inner peripheral wall 503 having a flat cylindrical shape and rising from an outer peripheral edge of the opening portion 501, and an outer peripheral wall 504 having a flat cylindrical shape and rising from an outer peripheral edge of the bottom wall 502.

[0029] Three sets of capacitor element units 10 are housed in the housing 500. Six capacitor elements 100 are arranged annularly in the housing 500 to surround the opening portion 501 in an orientation in which a flat surface 103a of the peripheral surface 103 of the inner peripheral wall 503 faces.

[0030] The filling resin 600 is a thermosetting resin, such as an epoxy resin. The filling resin 600 is poured into the housing 500 in a liquid state and cured by heating.

[0031] All six capacitor elements 100 are embedded in filler resin 600. Thus, the six capacitor elements 100 are protected from moisture and shock by the housing 500 and the filler resin 600.

[0032] The upper end portions of the first busbar 200 and the second busbar 300 in three sets of busbar units 11 are exposed to the outside from the filling resin 600. The upper end portion of the first busbar 200 and the upper end portion of the second busbar 300 are terminal connecting portions to which external terminals are connected.

[0033] The film capacitor 1 is used together with an inverter as part of a drive device for driving an electric motor of a hybrid vehicle or an electric vehicle. The inverter converts direct current energy supplied by a battery into alternating current energy. The film capacitor 1 is used, for example, as a smoothing capacitor for an inverter.

[0034] Fig. 5 is a diagram illustrating a state in which the film capacitor 1 and the electric motor 2 are fixed to the bracket 3.

[0035] The film capacitor 1 is attached to the bracket 3 together with the electric motor 2. An inverter (not shown) is also attached to the bracket 3. The electric motor 2, the film capacitor 1, and the inverter are integrated into a motor unit 4 via the bracket 3.

[0036] The diameter of the opening portion 501 of the housing 500, i.e., the caliber D1, is larger than the diameter D2 of the rotor shaft 2a of the electric motor 2, and the rotor shaft 2a protrudes through the opening portion 501 and the inner peripheral wall 503 of the housing 500, which is fixed to the bracket 3. In the film capacitor 1, six capacitor elements 100 are arranged in the housing 500 so as to surround the rotor shaft 2a.

[0037] In a state where the electric motor 2 is installed in an electric vehicle or the like, a gap is relatively easily formed around the rotor shaft 2a. Since the film capacitor 1 is configured in the present embodiment with six capacitor elements 100 arranged to surround the rotor shaft 2a, the gap around the rotor shaft 2a can be effectively utilized. As a result, the motor unit 4 can be made compact. < Effects of the embodiment >

[0038] As described above, the present embodiment has the following effects.

[0039] The film capacitor 1 includes a plurality (six) of capacitor elements 100, a case 500 that accommodates the plurality of capacitor elements 100, and a filling resin 600 with which the case 500 is filled. The case 500 includes a bottom wall 502 having an opening portion 501 in the center of the bottom wall 502, an inner peripheral wall 503 having a tubular shape and rising from the outer peripheral edge of the opening portion 501, and an outer peripheral wall 504 having a tubular shape and rising from the outer peripheral edge of the bottom wall 502. The plurality of capacitor elements 100 are arranged in the case 500 so as to surround the opening portion 501.

[0040] According to this configuration, since the film capacitor 1 is installed such that an object such as the rotor shaft 2a of the electric motor 2 is inserted into the opening portion 501 of the housing 500, the plurality (six) of capacitor elements 100 can be arranged to surround the object.

[0041] Furthermore, each capacitor element 100 in the film capacitor 1 includes an electrode 110 and an electrode 120 at both the end surface 101 and the end surface 102. The peripheral surface 103 between the end surface 101 and the end surface 102 includes the pair of flat surfaces 103a facing each other and the pair of curved surfaces 103b connecting the pair of flat surfaces 103a. The peripheral surface 103 is long in the direction in which the pair of curved surfaces 103b are aligned. The plurality of capacitor elements 100 are arranged in the case 500 in the orientation in which a flat surface 103a faces the inner peripheral wall 503.

[0042] According to this configuration, the size of the case 500 in an orientation (radial direction) parallel to the bottom wall 502 can be reduced compared to a case in which the plurality of capacitor elements 100 are arranged in the case 500 in the orientation in which a curved surface 103b faces the inner peripheral wall 503. Thus, the film capacitor 1 can be made compact.

[0043] Furthermore, in the film capacitor 1, in a housing in which the film capacitor 1 is integrated with the electric motor 2, the caliber D1 of the opening portion 501 of the housing 500 is set to be larger than the diameter D2 of the rotor shaft 2a, so that the rotor shaft 2a of the electric motor 2 protrudes through the opening portion 501.

[0044] According to this configuration, the film capacitor 1 can be installed around the rotor shaft 2a, effectively utilizing the space. This allows the motor unit 4, in which the film capacitor 1 is integrated into the electric motor 2, to be made compact.

[0045] Furthermore, in the film capacitor 1, the opening portion 501 through which the rotor shaft 2a protrudes has a circular shape.

[0046] According to this configuration, since a distance between the peripheral surface of the rotor shaft 2a and the outer peripheral edge of the opening portion 501 can be shortened, the plurality of capacitor elements 100 can be arranged near the rotor shaft 2a. Thus, the motor unit 4 can be made more compact.

[0047] The embodiment of the present disclosure has been described above. However, the present disclosure is not limited to the above-described embodiment, and various modifications may be made to application examples according to the present disclosure besides the above-described embodiment. <Modifikation 1>

[0048] Fig. 6 is a plan view showing the film capacitor 1A in a state where it is not filled with filling resin 600 according to Modification 1.

[0049] The film capacitor 1A of the present modification includes the case 510 instead of the case 500 of the film capacitor 1 of the exemplary embodiment.

[0050] The housing 510 includes a bottom wall 512 having a disc shape and an opening portion 511 at the center of the bottom wall 512, an inner peripheral wall 513 having a flat tubular shape rising from an outer peripheral edge of the opening portion 511, and an outer peripheral wall 514 having a flat cylindrical shape rising from an outer peripheral edge of the bottom wall 512. An outer peripheral edge of the opening portion 511 has a shape that runs along one of the flat surfaces 103a (on the inner peripheral side) of six capacitor elements 100 arranged in the housing 510. Further, the inner peripheral wall 513 has a tubular shape corresponding to the outer peripheral edge of the opening portion 511.

[0051] In the present modification, since the gap between the inner peripheral wall 513 and one of the flat surfaces 103a of the six capacitor elements 100 can be reduced, the filling amount of the filling resin 600 in the case 510 can be reduced.

[0052] Note that in the present modification, an outer peripheral edge of the bottom wall 512 may have a shape that extends along another flat surface 103a (on the outer peripheral side) of the six capacitor elements 100, and the outer peripheral wall 514 may have a tubular shape corresponding to the outer peripheral edge of the bottom wall 512. In this case, the filling amount of the filling resin 600 in the case 510 can be further reduced. <Modifikation 2>

[0053] Fig. 7 is a plan view showing the film capacitor 1B in a state where it is not filled with filler resin 600 according to Modification 2.

[0054] The film capacitor 1B of the present modification includes a case 520 formed in the shape of a double square tubular box with an open top surface.

[0055] The housing 520 includes a bottom wall 522 having a square plate shape and an opening portion 521 having a square shape in the center of the bottom wall 522, an inner peripheral wall 523 having a flat square tubular shape rising from an outer peripheral edge of the opening portion 521, and an outer peripheral wall 524 having a flat square tubular shape rising from an outer peripheral edge of the bottom wall 522.

[0056] Two sets of first capacitor element units 10a and two sets of second capacitor element units 10b are housed in the housing 520. The first capacitor element unit 10a includes two capacitor elements 100 and one busbar 11. The second capacitor element unit 10b includes one capacitor element 100 and one busbar 11.

[0057] In the housing 520, six capacitor elements 100 are arranged annularly to surround the opening portion 521 in an orientation in which a flat surface 103a of the peripheral surface 103 faces the inner peripheral wall 523.

[0058] Note that in the present modification, the opening portion 521 may be circular, and the inner peripheral wall 523 may be cylindrical. Alternatively, the bottom wall 522 may be disc-shaped, including the square opening portion 521, and the outer peripheral wall 524 may be changed to be cylindrical. <Modifikation 3>

[0059] Fig. 8 is a plan view showing the film capacitor 1C in a state where it is not filled with filler resin 600 according to Modification 3.

[0060] The film capacitor 1C of the present modification includes a case 500A having a double cylindrical box shape with an open top surface, wherein an outer diameter of the bottom wall 502 and an inner diameter of the outer peripheral wall 504 are larger than those of the case 500 of the above embodiment. The case 500A is larger than the case 500 in a direction (radial direction) parallel to the bottom wall 502.

[0061] Four sets of capacitor element units 10A are housed in the housing 500A. The capacitor element unit 10A includes two capacitor elements 100 and one busbar 11. The two capacitor elements 100 are arranged on both sides of the busbar 11 so that their flat surfaces 103a of the peripheral surfaces 103 face each other. The flat surfaces 103a are not parallel to each other, and the distance between the flat surfaces increases with increasing distance from the busbar 11.

[0062] In the case 500A, eight capacitor elements 100 are arranged annularly to surround the opening portion 501 in an orientation in which a curved surface 103b of the peripheral surface 103 of the inner peripheral wall 503 faces. <Modifikation 4>

[0063] Fig. 9 is a plan view showing the film capacitor 1D in a state where it is not filled with filling resin 600 according to Modification 4.

[0064] The film capacitor 1D according to the present modification includes a case 500B having a double cylindrical box shape with an open top surface, wherein an outer diameter of the bottom wall 502 and an inner diameter of the outer peripheral wall 504 are slightly larger than those of the case 500 according to the above exemplary embodiment. A size of the case 500B in a direction (radial direction) parallel to the bottom wall 502 is slightly larger than that of the case 500.

[0065] The housing 500B contains six capacitor elements 100. A pair of square plate-shaped busbars 700 are connected to the first electrode 110 and the second electrode 120 of each capacitor element 100.

[0066] In the case 500B, six capacitor elements 100 are arranged annularly to surround the opening portion 501 in an orientation in which the end surface 101, ie, the first electrode 110, faces the inner peripheral wall 503.

[0067] In a state where the casing 500B is filled with filling resin 600, upper end portions of the pair of bus bars 700 are exposed to the outside as terminal connecting parts connected to external terminals.

[0068] Note that in the film capacitor 1D of the present modification, in the case 500B, each capacitor element 100 is separated from the inner peripheral wall 503, compared to a case of the film capacitor 1 of the above exemplary embodiment, so that corners of capacitor elements 100 adjacent to each other in the circumferential direction do not come into contact with each other. Thus, a size of the case 500B in the radial direction is larger than a size of the case 500 of the above exemplary embodiment in the radial direction. <Andere Modifikationen>

[0069] In the above embodiment, the film capacitor 1 is integrated into the motor unit 4 as an associated component of the electric motor 2 of the electric vehicle or the like. The rotor shaft 2a of the electric motor 2 is inserted into the opening portion 501 of the housing 500. However, the film capacitor 1 may also be incorporated into another external device. In this case, a predetermined object, such as an electrical component included in the external device, is inserted into the opening portion 501 of the housing 500.

[0070] Furthermore, in the above-described embodiment and modifications 1, 2, and 4, each of the film capacitors 1, 1A, 1B, and 1D includes six capacitor elements 100. Moreover, in the above-described modification 3, the film capacitor 1C includes eight capacitor elements 100. However, the number of capacitor elements 100 may be changed accordingly.

[0071] Furthermore, in the above-described embodiment and Modifications 1 to 4, the plurality of capacitor elements 100 may be electrically connected by a set of the first busbar and the second busbar. In this case, an insulating layer may be disposed between the first busbar and the second busbar as needed.

[0072] Furthermore, in the above-described embodiment and modifications 1 to 4, the capacitor element 100 is formed by overlapping two metallized films formed by vapor-depositing aluminum on the dielectric film, and winding or stacking the overlapped metallized films. However, these capacitor elements 100 can also be formed by overlapping metallized films formed by vapor-depositing aluminum on both surfaces of a dielectric film and an insulating film, and winding or stacking the overlapped films.

[0073] Furthermore, in the above exemplary embodiment and modifications 1 to 4, examples of the capacitor of the present disclosure include film capacitors 1, 1A, 1B, 1C, and 1D. However, the present disclosure is also applicable to capacitors other than the film capacitor.

[0074] Furthermore, various modifications can be appropriately made to the exemplary embodiments of the present disclosure within the scope of the technical idea disclosed in the claims. Industrial applicability

[0075] The present disclosure is useful for providing capacitors used in various electronic devices, electrical devices, industrial devices, and electrical devices for vehicles, among others. Reference symbols in the drawings 1, 1A, 1B, 1C, 1D film capacitor (capacitor) 2 electric motor 2a Rotor shaft 100 capacitor elements 101, 102 end face 103 Circumferential area 103a flat surface 103b curved surface 110 first electrode (electrode) 120 second electrode (electrode) 500, 500A, 500B, 510, 520 housings 501, 511, 521 opening section 502, 512, 522 floor wall 503, 513, 523 inner peripheral wall 504, 514, 524 outer peripheral wall 600 filling resin QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2020 / 031676

[0004]

Claims

[1] Capacitor, comprising: a plurality of capacitor elements; a housing that houses the plurality of capacitor elements; and a filling resin with which the housing is filled, whereby the housing includes: a bottom wall including an opening portion in a center of the bottom wall, an inner peripheral wall having a tubular shape and rising from an outer peripheral edge of the opening portion, and an outer peripheral wall having the tubular shape and rising from the outer peripheral edge of the bottom wall, and the plurality of capacitor elements are arranged in the housing to surround the opening portion. [2] Capacitor according to claim 1, wherein: each of the plurality of capacitor elements comprises: an electrode on each of the two end faces of each of the plurality of capacitor elements, a circumferential surface between both end surfaces, comprising a pair of opposing flat surfaces and a pair of curved surfaces connecting the pair of flat surfaces, each of the plurality of capacitor elements is elongated in a direction in which the pair of curved surfaces is aligned, and the plurality of capacitor elements are arranged such that one of the pairs of flat surfaces faces the inner peripheral wall in the housing. [3] The capacitor according to claim 1 or 2, wherein in a case where the capacitor is integrated with an electric motor, a size of the opening portion is larger than a diameter of a rotor shaft, the rotor shaft of the electric motor protruding through the opening portion. [4] The capacitor according to claim 1 or 2, wherein the opening portion has a circular shape.

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