Film capacitor

Abstract

We provide film capacitors that can reduce ESL (Effective System Loss). [Solution] The film capacitor C of the present invention comprises a plurality of capacitor elements 3 having a first electrode 31 and a second electrode 32 on both end faces, a first busbar 1 having a first external connection part 11 for connection to external equipment and connected to the first electrode 31, a second busbar 2 having a second external connection part 21 for connection to external equipment and connected to the second electrode 32, a first insulating part 4 that insulates the first electrode 31 and the second busbar 2, a case 7 having an opening that houses the plurality of capacitor elements 3, and a filling resin 8 that fills the case 7. The capacitor element is characterized in that multiple capacitor elements 3 are arranged in parallel with their respective first electrodes 31 facing the opening side of the case 7, and a second busbar 2 is inserted between adjacent capacitor elements 3.

Description

Technical Field

[0001] The present invention relates to a film capacitor.

Background Art

[0002] In recent years, the introduction of electric vehicles and hybrid electric vehicles has been progressing in the automotive industry.

[0003] Since the motors used in these electric vehicles operate at a high voltage of several hundred volts, film capacitors having high breakdown voltage and low-loss electrical characteristics have come to be used as the capacitors used in relation to the motors.

[0004] For such film capacitors, depending on the layout of each device, it is required to arrange external connection terminals at various positions.

[0005] For example, in Patent Document 1, when arranging the external connection terminals at the center of the upper surface of the capacitor, the lower bus bar connected to the lower electrode of the capacitor element is routed outside the capacitor element and then wired to the center of the upper surface of the capacitor. And by bringing the upper bus bar connected to the upper electrode of the capacitor element and the lower bus bar close to each other, reduction of the equivalent series inductance (hereinafter referred to as ESL) is disclosed.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, the capacitor described in that document had a problem in that, because the lower busbar was routed around the outside of the capacitor element, the length of the lower busbar that had to be physically routed was inevitably long, and in practice, the ESL became larger than the ESL reduction effect from the proximity of the upper and lower busbars.

[0008] This invention has been made in view of the above problems, and aims to provide a film capacitor that can reduce ESL. [Means for solving the problem]

[0009] To achieve the above objective, the present invention provides the following means.

[0010] [1] A plurality of capacitor elements having a first electrode and a second electrode on both end faces, It has a first external connection section used for connecting to an external device, and a first busbar connected to the first electrode, It has a second external connection section used for connecting to external equipment, and a second busbar connected to the second electrode, A case having an opening and housing the plurality of capacitor elements, The case comprises a filling resin, The plurality of capacitor elements are arranged in parallel with their respective first electrodes facing the opening side of the case. The second busbar is characterized by being inserted between adjacent capacitor elements.

[0011] According to this invention, since the second busbar is inserted between adjacent capacitor elements, the length of the second busbar can be shortened without routing the second busbar, thus reducing the ESL (Electron Space Level).

[0012] Furthermore, since the length of the second busbar can be shortened, the material cost of the second busbar can be reduced, and the cost of the film capacitor can also be reduced.

[0013] [2] It has a first insulating portion that insulates the first electrode from the second busbar, and a second insulating portion that insulates the first busbar from the second busbar.

[0014] According to this invention, since there is a first insulating part that insulates the first electrode and the second busbar, and a second insulating part that insulates the first busbar and the second busbar, reliable insulation can be achieved between the first electrode and the second busbar, and between the first and second busbars.

[0015] [3] The first insulating part and the second insulating part are integrally molded and placed over the second busbar so as to surround the second busbar.

[0016] According to this invention, the first insulating part and the second insulating part are integrally molded and placed over the second busbar so as to surround it, thereby reducing the number of parts while insulating the second busbar from the first electrode and the first busbar.

[0017] [4] The first busbar has an annular portion.

[0018] According to this invention, since the first busbar has an annular portion, the degree of freedom of the current flow path can be increased, and thus the equivalent series resistance (hereinafter referred to as ESR) can be reduced.

[0019] [5] The first busbar has a first rising portion perpendicular to the parallel direction of the plurality of capacitor elements, The second busbar has a second rising portion perpendicular to the parallel direction of the plurality of capacitor elements, The second insulating portion insulates the first and second rising portions at a proximity position where they overlap and are close to each other.

[0020] According to this invention, the second insulating portion insulates the first and second rising portions at a close proximity position where they overlap, thereby ensuring reliable insulation between the first and second rising portions and further reducing ESL (Extreme Sediment Level). [Effect of the Invention]

[0021] According to the present invention, a film capacitor capable of reducing ESL can be provided. [Brief Description of the Drawings]

[0022] [Figure 1] It is a perspective view showing the film capacitor of this embodiment. [Figure 2] In the film capacitor of this embodiment, it is a perspective view showing a state where the case and the filling resin are removed, (a) is a view seen from above the first electrode, and (b) is a view seen from below the second electrode. [Figure 3] It is a perspective view showing the first bus bar of this embodiment. [Figure 4] It is a perspective view showing the second bus bar of this embodiment, (a) is a view seen from the front direction, and (b) is a view seen from the rear direction. [Figure 5] It is a perspective view showing the first insulating part and the second insulating part of this embodiment. [Figure 6] It is a perspective view showing the positional relationship between the first bus bar and the second bus bar of this embodiment. [Figure 7] It is a perspective view showing the positional relationship between the first bus bar, the second bus bar, the first insulating part, and the second insulating part of this embodiment. [Modes for Carrying Out the Invention]

[0023] In this embodiment, in FIG. 2(a), the parallel direction of the three capacitor elements 3 is the left-right direction, the direction perpendicular to the left-right direction and horizontal with respect to the opening of the case 7 is the front-rear direction, and the direction perpendicular to the left-right direction and the front-rear direction is the up-down direction or the height direction for explanation.

[0024] (Film Capacitor) The film capacitor of the present invention is used in an electronic circuit of an electronic device, and is particularly preferably used in an electronic circuit related to an electric vehicle or a hybrid electric vehicle.

[0025] The film capacitor C of this embodiment comprises six capacitor elements 3, a first busbar 1, a second busbar 2, a first insulating part 4, a second insulating part 5, a case 7, and a filling resin 8.

[0026] (Capacitor element) The capacitor element 3 of this embodiment has a first electrode 31 and a second electrode 32 on both end faces.

[0027] The capacitor element 3 is formed by overlapping and winding two metallized films, each having aluminum deposited on a dielectric film, and then applying a metallizing treatment to both ends by spraying zinc onto them, thereby forming a first electrode 31 on one end and a second electrode 32 on the other end.

[0028] Examples of dielectric films that can be used include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polypropylene (PP).

[0029] In this embodiment, aluminum is deposited on a dielectric film, but the invention is not limited to this, and other metals such as zinc and magnesium may be deposited. Alternatively, multiple of these metals may be deposited, or an alloy composed of these metals may be deposited.

[0030] Furthermore, although zinc is used for the metallization treatment in this embodiment, it is not limited to zinc, and other metals such as tin may also be used.

[0031] As shown in Figure 2(a), in this embodiment, the first electrode 31 of each of the six capacitor elements 3 is facing the opening side, i.e., upward, of the case 7 described later, and the capacitor elements 3 are arranged in parallel in the left-right direction in groups of three, and then arranged in the front-back direction.

[0032] In this embodiment, six capacitor elements 3 are used, but the invention is not limited to this. Depending on the desired capacitance of the film capacitor C, two, four, or eight or more capacitor elements 3 may be used.

[0033] For example, if four capacitor elements 3 are used, the first electrodes 31 of each of the four capacitor elements 3 may be directed toward the opening side of the case 7, and the capacitor elements 3 may be arranged in pairs in the left-right direction and then in the front-back direction.

[0034] (First bus bar) As shown in Figure 2(a), the first busbar 1 is connected to the first electrode 31 of each capacitor element 3.

[0035] The first busbar 1 electrically connects the first electrode 31 of each capacitor element 3 to an external device.

[0036] The first busbar 1 is formed by cutting and bending a conductive metal plate to a predetermined shape, and as shown in Figures 2(a) and 3, it has a first substrate portion 16 and a first rising portion 12. Aluminum plates or copper plates can be used as this conductive metal plate.

[0037] (First circuit board section) The first substrate portion 16 is electrically connected to the first electrode 31 of each capacitor element 3.

[0038] The first substrate portion 16 is formed parallel to the parallel direction of the capacitor elements 3, and as shown in Figure 3, it consists of a flat plate portion 162, a pair of extension portions 163, and a connecting portion 164.

[0039] (flat plate part) As shown in Figure 2(a), the flat plate portion 162 is electrically connected to the first electrodes 31 of the three capacitor elements 3 arranged in parallel on the rear side, and is formed in a roughly rectangular shape in plan view.

[0040] (extending part) As shown in Figure 3, the pair of extensions 163 are formed to extend forward from the flat plate portion 162. The left extension 163 is electrically connected to the first electrode 31 of the leftmost of the three capacitor elements 3 arranged in parallel at the front, and the right extension 163 is electrically connected to the first electrode 31 of the rightmost capacitor element 3.

[0041] (Connection part) The connecting portion 164 is formed to connect the front ends of a pair of extension portions 163 and is electrically connected to the first electrode 31 of the central capacitor element 3 among the three capacitor elements 3 arranged in parallel on the front side.

[0042] (Circular section) As the first substrate portion 16 is composed of the flat plate portion 162, a pair of extension portions 163, and a connecting portion 164, the first substrate portion 16 (first busbar 1) has an annular portion 13, as shown in Figures 2(a) and 3.

[0043] The annular portion 13 is electrically connected to the first electrode 31 of each capacitor element 3 and is formed to span across all capacitor elements 3.

[0044] In this embodiment, the first busbar 1 has an annular portion 13, which increases the degree of freedom in the current flow path and thus reduces ESR.

[0045] (Through hole) In this embodiment, the presence of the annular portion 13 allows for the formation of a through hole 161 in the first substrate portion 16.

[0046] In this embodiment, the through-hole 161 is formed such that, when viewed from above in Figure 2(a), at least a portion of the gap between adjacent capacitor elements 3 in the front-to-back direction in the center is visible, allowing the second external connection portion 21 in the center of the second busbar 2 (described later) to be inserted through the through-hole 161 from below.

[0047] (First connection pin) As shown in Figure 2(a), the first substrate portion 16 is provided with a plurality of first connection pins 15.

[0048] The first connection pin 15 electrically connects the first substrate portion 16 and the first electrode 31 of the capacitor element 3.

[0049] In this embodiment, one or two first connection pins 15 are connected to the first electrode 31 of each capacitor element 3 by soldering or the like. This electrically connects the first busbar 1 to each capacitor element 3.

[0050] (First Startup Department) The first riser section 12 is formed perpendicular (in the height direction) to the parallel direction of the capacitor elements 3.

[0051] The first rise-up section 12 is positioned on the front end side of the first electrode 31 of the three capacitor elements 3 arranged in parallel at the rear of the first substrate section 16, and in this embodiment, three first rise-up sections 12 are provided.

[0052] As shown in Figure 3, each first riser section 12 has a first external connection section 11 and a first proximity section 14.

[0053] (First external connection section) The first external connection section 11 is used for electrical connection between the first busbar 1 and external equipment.

[0054] The first external connection portion 11 is formed as the upper portion of the first rise portion 12 by bending the portion approximately midway in the vertical direction of the first rise portion 12 forward and upward.

[0055] In this embodiment, three first external connection units 11 are arranged among the six capacitor elements 3, with each unit positioned between adjacent capacitor elements 3 in the front-to-back direction.

[0056] The first external connection portion 11 has a first mounting hole 17 at its upper end.

[0057] The first external connection section 11 is electrically connected to the terminals (not shown) of the external device by screw fastening through the first mounting hole 17. This connects the first busbar 1 to the external device.

[0058] In this embodiment, as described above, three first external connection parts 11 are formed between adjacent capacitor elements 3 in the front-to-back direction. However, the embodiment is not limited to this, and the first external connection parts 11 may be limited to those located in the center, right side, or left side in Figure 3, or they may be limited to those located in the center and right side, center and left side, or both left and right sides.

[0059] (First proximity section) The first proximity section 14 is where the first riser section 12 and the second riser section 22 of the second busbar 2, which will be described later, overlap and come into close proximity.

[0060] As shown in Figures 3 and 6, the first proximity portion 14 in this embodiment is formed as approximately the left half of each first rising portion 12.

[0061] (Second bus bar) As shown in Figure 2(b), the second busbar 2 is connected to the second electrode 32 of each capacitor element 3.

[0062] The second busbar 2 electrically connects the second electrode 32 of each capacitor element 3 to an external device.

[0063] The second busbar 2, like the first busbar 1, is formed by cutting and bending a conductive metal plate to a predetermined shape, and has multiple second substrate portions 26 and second rising portions 22, as shown in Figures 4(a) and 4(b). Aluminum plates or copper plates can be used as the conductive metal plate.

[0064] (Second circuit board section) The second substrate portion 26 is electrically connected to the second electrode 32 of the capacitor element 3.

[0065] The second substrate portion 26 is formed parallel to the parallel direction of the capacitor elements 3, and in this embodiment, a total of seven second substrate portions 26 are formed: four on the front side of the second rise portion 22 and three on the rear side of the second rise portion 22 (see Figures 4(a) and 4(b)).

[0066] (Second connection pin) Each second substrate section 26 has one or two second connection pins 25.

[0067] The second connection pin 25 electrically connects the second substrate portion 26 of the second busbar 2 to the second electrode 32 of the capacitor element 3.

[0068] In this embodiment, two second connection pins 25 are connected to the second electrode 32 of each capacitor element 3 by soldering or the like. This electrically connects the second busbar 2 to each capacitor element 3.

[0069] (Second Startup Department) The second rise section 22 is formed perpendicular (in the height direction) to the parallel direction of the capacitor elements 3.

[0070] The second riser section 22 is inserted between adjacent capacitor elements 3, one at the front and one at the back. In other words, a portion of the second busbar 2 is inserted between adjacent capacitor elements 3, one at the front and one at the back.

[0071] As shown in Figure 6, the second riser section 22 has a second external connection section 21 and a second proximity section 24.

[0072] (Second external connection section) The second external connection section 21 is used for electrical connection between the second busbar 2 and external equipment.

[0073] In this embodiment, a total of three second external connection units 21 are arranged among the six capacitor elements 3, with each unit positioned between adjacent capacitor elements 3 in the front-to-back direction.

[0074] As shown in Figure 6, of the three second external connection parts 21, the left and right second external connection parts 21 are formed as the upper parts of the second rising part 22 by extending the second rising part 22 upward.

[0075] Furthermore, the central of the three second external connection parts 21 is formed as the upper part of the second rising part 22 by bending the approximately middle portion of the second rising part 22 in the vertical direction backward and upward.

[0076] Furthermore, as shown in Figure 7, in this embodiment, the central of the three second external connection parts 21 is covered by the second insulating part 5 (described later) in all parts except near the upper end, and is inserted through the through hole 161 of the first busbar 1.

[0077] The second external connection portion 21 has a second mounting hole 27 at its upper end.

[0078] The second external connection section 21 is electrically connected to the terminals (not shown) of the external device by screw fastening through the second mounting hole 27. This connects the second busbar 2 to the external device.

[0079] In this embodiment, as described above, three second external connection portions 21 are formed between adjacent capacitor elements 3 in the front-to-back direction. However, the embodiment is not limited to this, and the second external connection portions 21 may be limited to those located in the center, right side, or left side, as shown in Figure 6, or they may be limited to those located in the center and right side, center and left side, or both sides.

[0080] (Second proximity section) The second proximity section 24 is where the second rising section 22 and the first rising section 12 overlap and come into close proximity.

[0081] As shown in Figures 4(a), 4(b), and 6, the second proximity portion 24 in this embodiment is formed approximately in the center of the height direction of the second rising portion 22, in other words, as the base end of the second external connection portion 21.

[0082] (First insulation section) As shown in Figures 2(a) and 7, the film capacitor C of this embodiment has three first insulating parts 4. In this embodiment, the first insulating parts 4 are components of the insulating member M.

[0083] The first insulating part 4 insulates the first electrode 31 from the second busbar 2 and is made of a resin such as polyphenylene sulfide (PPS).

[0084] As shown in Figure 5, each first insulating section 4 has openings on its bottom and both left and right sides, and is roughly U-shaped when viewed from the side.

[0085] Each insulating member M, having a first insulating portion 4, is placed over the second busbar 2 so as to cover the portion of the second rising portion 22 of the second busbar 2 other than the second external connection portion 21.

[0086] (Second insulation section) As shown in Figures 2(a) and 7, the film capacitor C of this embodiment has three second insulating parts 5. In this embodiment, the second insulating parts 5 are components of the insulating member M.

[0087] The second insulating part 5 insulates the first busbar 1 and the second busbar 2, and is made of a resin such as polyphenylene sulfide (PPS).

[0088] As shown in Figure 5, each second insulating section 5 has an open upper end, and the left second insulating section 5 also has an open entire left side.

[0089] Each second insulating part 5 is placed over the second busbar 2 by inserting approximately the upper half of the second external connection part 21 of the second busbar 2 through its opening.

[0090] As shown in Figure 7, in this embodiment, an insulating member M, in which the first insulating part 4 and the second insulating part 5 are integrally molded, is placed over the second busbar 2 so as to surround it.

[0091] Although an insulating member M in which the first insulating part 4 and the second insulating part 5 are integrally molded is used as described above, the method is not limited to this, and the first insulating part 4 and the second insulating part 5 may be manufactured as separate components and joined together for use.

[0092] As in this embodiment, integrally molding the first insulating part 4 and the second insulating part 5 and covering the second busbar 2 so as to surround it is preferable because it reduces the number of parts compared to the case where the first insulating part 4 and the second insulating part 5 are manufactured as separate components, while still insulating the second busbar 2 from the first electrode 31 and the first busbar 1.

[0093] (case) As shown in Figure 1, the film capacitor C of this embodiment includes a case 7.

[0094] Case 7 houses multiple capacitor elements 3.

[0095] Case 7 is formed from a thermoplastic resin such as polyphenylene sulfide (PPS) in a substantially rectangular parallelepiped shape when viewed from above, with an open top surface, and in this embodiment, it houses six capacitor elements 3, a first busbar 1, a second busbar 2, a first insulating part 4, a second insulating part 5, and a filler resin 8 described later.

[0096] (Filling resin) The filling resin 8 in this embodiment is filled into the case 7, and is filled into the case 7 after housing the six capacitor elements 3, the first busbar 1, the second busbar 2, the first insulating part 4, and the second insulating part 5.

[0097] Epoxy resin or urethane resin can be used as the filler resin 8.

[0098] (Assembly Instructions) Next, the assembly procedure for the film capacitor C in this embodiment will be described.

[0099] First, the second bus bar 2 is positioned so that its second rising portion 22 is vertical.

[0100] Then, an insulating member M, which is integrally molded with the first insulating part 4 and the second insulating part 5, is placed above the second busbar 2, and the upper end of the second external connection part 21 of the second busbar 2 is inserted from below into the opening at the upper end of the second insulating part 5, and the insulating member is placed over the second busbar 2 so as to surround the second busbar 2.

[0101] Then, with each of the six capacitor elements 3 facing upwards, these capacitor elements 3 are brought into parallel contact with the insulating member M, which is formed by integrally molding the first insulating part 4 and the second insulating part 5, from both the front and back directions.

[0102] Subsequently, the first busbar 1 is positioned above the second busbar 2, and the first rising portion 12 of the first busbar 1 and the second rising portion 22 of the second busbar 2 are made parallel, and the second external connection portion 21 in the center of the second busbar 2 is inserted through the through hole 161 of the first busbar 1, so that the first busbar 1 is moved downward and positioned directly above the first insulating portion 4.

[0103] Then, the first connection pin 15 of the first busbar 1 and the second connection pin 25 of the second busbar 2 are soldered to the first electrode 31 and the second electrode 32, respectively.

[0104] Then, the capacitor elements 3, the first busbar 1, the second busbar 2, the first insulating part 4, and the second insulating part 5 are integrated and housed in the case 7, and liquid-phase filling resin 8 is injected up to the vicinity of the opening of the case 7.

[0105] After that, the case 7 is heated to harden the filling resin 8, and as shown in Figure 1, the film capacitor C of this embodiment is completed, in which the first external connection part 11 of the first busbar 1 and the second external connection part 21 and part of the second insulating part 5 of the second busbar 2 are exposed above the filling resin 8.

[0106] (effect) In this embodiment, the film capacitor C has a second busbar 2 inserted between adjacent capacitor elements 3. Therefore, the length of the second busbar 2 can be shortened without routing the busbar, thus reducing the ESL (Electromagnetic Slip Length). Furthermore, since the length of the second busbar 2 can be shortened, the material cost of the second busbar 2 can be reduced, making the film capacitor C more cost-effective.

[0107] Furthermore, since it has a second insulating part 5 that insulates the first busbar 1 and the second busbar 2, these busbars can be reliably insulated.

[0108] Furthermore, since the first insulating part 4 and the second insulating part 5 are integrally molded and placed over the second busbar 2 so as to surround it, the number of parts can be reduced while insulating the second busbar 2 from the first electrode 31 and the first busbar 1.

[0109] Furthermore, since the first busbar 1 has an annular portion 13, the degree of freedom in the current flow path can be increased, thus reducing ESR.

[0110] Furthermore, the second insulating section 5 insulates the first rising section 12 and the second rising section 22 at the second proximity section 24 where the first rising section 12 and the second rising section 22 overlap and are in close proximity. This ensures reliable insulation between the first rising section 12 and the second rising section 22, and further reduces ESL (Extreme Light Level).

[0111] (Other forms) In this embodiment, the second busbar 2 (second rise portion 22) was inserted between adjacent capacitor elements 3 in the front-rear direction, but it is not limited to this, and the second rise portion 22 of the second busbar 2 may be inserted between at least one of any adjacent capacitor elements 3.

[0112] In the above case as well, the same effects as in this embodiment can be obtained.

[0113] Furthermore, although this embodiment has an annular portion 13, a configuration without an annular portion 13 is also possible. For example, in Figure 3, the first busbar 1 may be configured without a connecting portion 164, thereby eliminating the annular portion 13. In this case, effects other than those resulting from having the annular portion 13 can be obtained. [Industrial applicability]

[0114] The film capacitor of the present invention can be suitably used in electric vehicles and hybrid electric vehicles. [Explanation of symbols]

[0115] 1: First bus bar 2: Second bus bar 3: Capacitor element 4: First insulating section 5: Second insulating section 7: Case 8: Filling resin 11: First external connection section 12: First Startup Department 13: Ring section 14: First Proximity Section 21: Second external connection section 22: Second Startup Department 24: Second Proximity Section 31: 1st electrode 32:Second electrode C: Film capacitor

Claims

1. A plurality of capacitor elements having a first electrode and a second electrode on both end faces, It has a first external connection part used for connecting to an external device, and a first busbar connected to the first electrode, It has a second external connection part used for connecting to an external device, and a second busbar connected to the second electrode, A case having an opening and housing the plurality of capacitor elements, The case comprises a filling resin, The plurality of capacitor elements are arranged in parallel with their respective first electrodes facing the opening side of the case. A film capacitor characterized in that the second busbar is inserted between adjacent capacitor elements.

2. A first insulating portion that insulates the first electrode and the second busbar, The film capacitor according to claim 1, having a second insulating portion that insulates the first busbar and the second busbar.

3. The film capacitor according to claim 2, wherein the first insulating portion and the second insulating portion are integrally molded and are placed over the second busbar so as to surround the second busbar.

4. The film capacitor according to any one of claims 1 to 3, wherein the first busbar has an annular portion.

5. The first busbar has a first rising portion perpendicular to the parallel direction of the plurality of capacitor elements, The second busbar has a second rising portion perpendicular to the parallel direction of the plurality of capacitor elements, The film capacitor according to claim 2, wherein the second insulating portion insulates the first and second rising portions at a close proximity position where the first and second rising portions overlap and are in close proximity.

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