Capacitor module

Abstract

A capacitor module according to the present disclosure comprises: one or more capacitor elements that have a first electrode, a second electrode, and a side surface that connects the first electrode and the second electrode; a first bus bar that is electrically connected to the first electrode; a second bus bar that is electrically connected to the second electrode; an insulating member that insulates the first bus bar and the second bus bar from each other; a case that houses the at least one or more capacitor elements; and a sealing resin that fills the case. The insulating member has a first insulation part that extends along a side surface in a direction from the second electrode toward the first electrode, and a second insulation part extending along the second bus bar. The first bus bar has a first contact part that contacts the first electrode, a first extension part that extends along a side surface, a second extension part that extends along the first insulation part, and a third extension part that extends along the second insulation part. The second bus bar has a second contact part that contacts the second electrode and a fourth extension part that extends along the second insulation part. The first extension part is disposed at a position closer to the side surface than the second extension part.

Description

Capacitor Module

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

[0002] 2. Description of the Related Art A capacitor module is known that includes a capacitor element housed in a case and a bus bar connected to the capacitor element.

[0003] For example, Patent Document 1 discloses a film capacitor including a capacitor element, a first bus bar, a second bus bar, a case, and a filling resin.

[0004] International Publication No. 2017 / 081853

[0005] The film capacitor described in Patent Document 1 has a problem in that it is difficult to reduce the inductance.

[0006] The present disclosure provides a capacitor module that can reduce inductance.

[0007] a first bus bar electrically connected to the first electrode; a second bus bar electrically connected to the second electrode; an insulating member insulating the first bus bar from the second bus bar; a case accommodating at least the one or more capacitor elements; and a sealing resin filled in the case, wherein the insulating member has a first insulating portion extending along the side surface in a direction from the second electrode toward the first electrode, and a second insulating portion extending along the second bus bar, and the first bus bar has a first contact portion in contact with the first electrode, a first extending portion extending along the side surface, a second extending portion extending along the first insulating portion, and a third extending portion extending along the second insulating portion, The second bus bar has a second contact portion that contacts the second electrode and a fourth extension portion that extends along the second insulating portion, and the first extension portion is positioned closer to the side surface than the second extension portion.

[0008] According to the present disclosure, a capacitor module capable of reducing inductance can be provided.

[0009] 1 is a perspective view showing a capacitor element 10 included in the capacitor module 100 of FIG. 1; FIG. 1 is an enlarged view of a region R1 of FIG. 1; FIG. 4 is an enlarged view of a region R2 of FIG. 4;

[0010] (Background to the Disclosure) In some capacitor modules, two bus bars are arranged opposite each other to reduce inductance. For example, in the film capacitor disclosed in Patent Document 1, a first bus bar and a second bus bar each include a first overlapping portion and a second overlapping portion that overlap each other with an insulating plate interposed therebetween.

[0011] Furthermore, by bringing the side of the capacitor element as close as possible to the bus bar, the electric field generated by the current flowing through the capacitor element and the electric field generated by the current flowing through the bus bar can cancel each other out, thereby further reducing the inductance of the capacitor module.

[0012] In the film capacitor of Patent Document 1, the first bus bar and the second bus bar overlap with an insulating plate interposed therebetween. The insulating plate has a rear plate portion disposed along the side surface of the capacitor element to ensure a creepage distance between the first bus bar and the second bus bar. Due to the rear plate portion, it is difficult to make the distance between the side surface of the capacitor element and the second bus bar smaller than the thickness of the insulating plate in the film capacitor of Patent Document 1. This makes it difficult to further reduce inductance.

[0013] The present inventors have investigated a capacitor module that allows the bus bars to be placed even closer to the side surfaces of the capacitor elements in order to further reduce the inductance of the capacitor module, and have arrived at the following invention.

[0014] (Embodiment 1) [Overall Configuration] Fig. 1 is a cross-sectional view schematically showing a capacitor module 100 according to embodiment 1. Fig. 2 is a perspective view showing a capacitor element 10 included in the capacitor module 100 of Fig. 1. Note that the X, Y, and Z directions in the figure indicate the horizontal, vertical, and height directions of the capacitor module 100, respectively.

[0015] 1 , capacitor module 100 includes capacitor element 10, first bus bar 20, second bus bar 30, insulating member 40, case 50, and sealing resin 60. In this embodiment, capacitor module 100 is formed by accommodating capacitor element 10, portions of first bus bar 20 and second bus bar 30, and portion of insulating member 40 in case 50, and sealing with sealing resin 60 filled in case 50.

[0016] Each component of the capacitor module 100 will now be described.

[0017] <Capacitor Element> Capacitor element 10 is a film capacitor composed of a laminate of dielectric films. More specifically, capacitor element 10 is formed by stacking dielectric films each having a metal vapor deposition film formed on its surface, and then rolling or laminating the stack. In this embodiment, the rolled dielectric film is pressed into a flat shape, thereby forming capacitor element 10 into a columnar shape with an oval cross section.

[0018] The dielectric film may be formed, for example, from a mixed resin solution containing phenoxy resin and MDI (diphenylmethane diisocyanate). Alternatively, a dielectric film may be formed from a mixed resin solution containing polyvinyl acetoacetal (PVAA) and tolylene diisocyanate (TDI). Forming the dielectric film from such a mixed resin solution can increase the glass transition temperature of the dielectric film to 120°C or higher, thereby increasing the heat resistance temperature of the capacitor element 10 to 120°C or higher. This improves the heat resistance of the capacitor module. Metal vapor deposition films formed on the surface of the dielectric film may include metals such as Al and Zn.

[0019] A first electrode 11 and a second electrode 12 for electrically connecting bus bar 20 are formed on both ends of the dielectric film laminate of capacitor element 10. First electrode 11 and second electrode 12 can be formed by thermal spraying a metal (conductive material) such as Al or Zn, for example.

[0020] 2, capacitor element 10 has side surfaces 13 connecting first electrode 11 and second electrode 12. In the present embodiment, capacitor element 10 is formed in a columnar shape having an oval cross section, and therefore side surfaces 13 of capacitor element 10 include a pair of flat portions 13a and a pair of curved portions 13b connecting the pair of flat portions 13a.

[0021] <Case> Case 50 is a case for accommodating capacitor element 10. Case 50 has, for example, a substantially rectangular parallelepiped shape and has an opening 51 through which a portion of bus bar 20 is exposed. Capacitor element 10 is accommodated in case 50. In the present embodiment, as shown in FIG. 1 , capacitor element 10 is disposed inside case 50 so that electrodes 11 and 12 face a side wall 52 of case 50 and flat portion 13a of side surface 13 faces a bottom wall 53 and opening 51 of the case. In addition, portions of first bus bar 20 and second bus bar 30 and a portion of insulating member 40 are accommodated in case 50.

[0022] The case 50 is made of synthetic resin such as polyphenylene sulfide (PPS resin) or polybutylene terephthalate (PBT resin).

[0023] 1 , sealing resin 60 is filled into case 50 to seal capacitor element 10 housed in case 50, parts of first bus bar 20 and second bus bar 30, and part of insulating member 40. Sealing resin 60 is made of a thermosetting resin such as epoxy resin or urethane resin, for example. A material with high fluidity and adhesiveness may also be used as the material for sealing resin 60.

[0024] <Busbars> The first busbar 20 is electrically connected to the first electrodes 11 of the capacitor elements 10, and functions as an external terminal of the capacitor module 100. The second busbar 30 is electrically connected to the second electrodes 12 of the capacitor elements 10, and functions as an external terminal of the capacitor module 100. The first busbar 20 and the second busbar 30 can be formed, for example, from conductive metal plates.

[0025] The first bus bar 20 has a first contact portion 21, a first extension portion 22, a second extension portion 23, and a third extension portion 24. The first contact portion 21 is a portion that contacts the first electrode 11 of the capacitor element 10. The first extension portion 22 is arranged to extend from an end portion 21a of the first contact portion 21 along a flat portion 13a of the side surface 13 of the capacitor element 10. The second extension portion 23 is arranged to extend along a first insulating portion 41 of an insulating member 40 (described later). The third extension portion 24 is arranged to extend from an end portion 23a of the second extension portion 23 along a second insulating portion 42 of the insulating member 40 (described later). As shown in FIG. 1 , the first extension portion 22 and the second extension portion 23 are arranged at different positions in the height direction. More specifically, the first extension portion 22 is arranged closer to the side surface 13 of the capacitor element 10 than the second extension portion 23.

[0026] The second bus bar 30 has a second contact portion 31 and a fourth extension portion 32. The second contact portion 31 is a portion that comes into contact with the second electrode 12 of the capacitor element 10. The fourth extension portion 32 is disposed to extend along the second insulating portion 42 of the insulating member 40.

[0027] The third extension portion 24 of the first bus bar 20 and the fourth extension portion 32 of the second bus bar 30 are arranged to overlap in the lateral direction (X direction) of the capacitor module 100 via the insulating member 40. Because the first bus bar 20 and the second bus bar 30 have an overlapping portion, the electric field generated by the current flowing through the third extension portion 24 of the first bus bar 20 and the electric field generated by the current flowing through the fourth extension portion 32 of the second bus bar 30 cancel each other out, thereby reducing the inductance of the capacitor module 100.

[0028] <Insulating Member> The insulating member 40 electrically insulates the first bus bar 20 and the second bus bar 30. The insulating member 40 is, for example, a plate-shaped member (insulating plate) made of a non-conductive material such as resin. The insulating member 40 can be made of a high-grade resin that can withstand high voltages, such as PPS (polyphenylene sulfide). The insulating member 40 has a thickness of, for example, 0.8 mm or more and 1.6 mm or less. By making the insulating member 40 have a thickness of 0.8 mm or more and 1.6 mm or less, it is possible to ensure a creepage distance between the first bus bar 20 and the second bus bar 30, or between the first bus bar 20 and the second electrode 12.

[0029] The insulating member 40 has a first insulating portion 41 that extends along the flat portion 13a of the side surface 13 of the capacitor element 10 in the direction from the second electrode 12 to the first electrode 11 of the capacitor element 10 (X direction), and a second insulating portion 42 that extends along the second bus bar 30. As shown in Fig. 1 , in this embodiment, the insulating member 40 is bent in an L shape when viewed from the vertical direction (Y direction) of the capacitor module 100.

[0030] The first insulating portion 41 insulates the first bus bar 20 from the second electrode 12. By arranging the first insulating portion 41 to extend along the side surface 13, the first bus bar 20 can be more reliably insulated from the second electrode 12. The first insulating portion may be arranged to at least partially overlap the second electrode 12 of the capacitor element 10 when viewed from the height direction (Z direction). By arranging the first insulating portion 41 in this manner, the insulation between the first bus bar 20 and the second electrode 12 can be more reliably achieved. The second insulating portion 42 insulates the first bus bar 20 from the second bus bar 30, particularly between the third extension portion 24 of the first bus bar 20 and the fourth extension portion 32 of the second bus bar 30.

[0031] Fig. 3 is an enlarged view of region R1 in Fig. 1. The arrangement of first bus bars 20 and insulating members 40 will be described with reference to Fig. 3.

[0032] As shown in FIG. 3 , the first extension portion 22 of the first bus bar 20 is disposed along the flat portion 13 a of the side surface 13 of the capacitor element 10. On the other hand, the second extension portion 23 of the first bus bar 20 is disposed along the first insulating portion 41 of the insulating member 40. Due to the thickness of the first insulating portion 41, the first extension portion 22 and the second extension portion 23 are disposed at different positions in the height direction (Z direction). In this embodiment, the first bus bar 20 has a connection portion 25 that connects the first extension portion 22 and the second extension portion 23. The connection portion 25 is disposed extending in a direction intersecting the side surface 13 of the capacitor element 10. In this embodiment, the connection portion 25 is disposed extending approximately perpendicular to the side surface of the capacitor element 10 and is disposed along the end surface 41 a of the first insulating portion 41. Therefore, the first bus bar 20 is formed into a shape that has a step S1 from the first extension portion 22 via the connection portion 25 toward the second extension portion 23. The first bus bar 20 is formed in a stepped shape, which allows the first extension portion 22 to be located close to the side surface 13 of the capacitor element 10. By locating the first bus bar 20 close to the side surface 13 of the capacitor element 10, the electric field generated by the current flowing through the first bus bar 20 and the electric field generated by the current flowing through the capacitor element 10 cancel each other out, thereby reducing the inductance of the capacitor module 100. Although the connection portion 25 is illustrated in FIG. 3 as extending linearly, the connection portion 25 may be partially or entirely curved due to the convenience of bending the first bus bar 20, which is a metal plate. Due to the curvature of the connection portion 25, the connection portion 25 may have a portion spaced apart from the first insulating portion 41.

[0033] 3, in this embodiment, first extension portion 22 is disposed so as to contact flat portion 13a of side surface 13 of capacitor element 10. The shorter the distance between first extension portion 22 and capacitor element 10, the more effectively inductance can be reduced.

[0034] [Effects] According to the above-described embodiment, the following effects can be achieved.

[0035] The capacitor module 100 includes a capacitor element 10, a first bus bar 20, a second bus bar 30, an insulating member 40, a case 50, and a sealing resin 60. The capacitor element 10 has a first electrode 11, a second electrode 12, and a side surface 13 connecting the first electrode 11 and the second electrode 12. The first bus bar 20 is electrically connected to the first electrode 11. The second bus bar 30 is electrically connected to the second electrode 12. The insulating member 40 insulates the first bus bar 20 and the second bus bar 30. The case 50 accommodates at least the capacitor element 10. The sealing resin 60 is filled into the case 50. The insulating member 40 has a first insulating portion 41 and a second insulating portion 42. The first insulating portion 41 extends along the side surface 13 in a direction from the second electrode 12 toward the first electrode 11. The second insulating portion 42 extends along the second bus bar 30. The first bus bar 20 has a first contact portion 21, a first extension portion 22, a second extension portion 23, and a third extension portion 24. The first contact portion 21 contacts the first electrode 11. The first extension portion 22 extends along the side surface 13. The second extension portion 23 extends along the first insulating portion 41. The third extension portion 24 extends along the second insulating portion 42. The second bus bar 30 has a second contact portion 31 and a fourth extension portion 32. The second contact portion 31 contacts the second electrode 12. The fourth extension portion 32 extends along the second insulating portion 42. The first extension portion 22 is located closer to the side surface 13 than the second extension portion 23.

[0036] This configuration makes it possible to provide a capacitor module that can reduce inductance. Since the first extension portion 22 of the first bus bar 20 can be placed close to the side surface 13 of the capacitor element 10, the electric fields between the first bus bar 20 and the capacitor element 10 cancel each other out, thereby reducing the inductance of the capacitor module 100.

[0037] The first bus bar 20 has a connection portion 25 extending in a direction intersecting the side surface 13 to connect the first extension portion 22 and the second extension portion 23 .

[0038] With this configuration, the first extension portion 22 and the second extension portion 23 can be arranged with a step therebetween, and the first extension portion 22 can be brought closer to the side surface 13 of the capacitor element 10. This allows the inductance of the capacitor module 100 to be further reduced.

[0039] The first extending portion 22 is in contact with the side surface 13 .

[0040] With this configuration, the first extending portion 22 of the first bus bar 20 comes into contact with the side surface 13 of the capacitor element 10, so that the inductance of the capacitor module 100 can be further reduced.

[0041] The first insulating portion 41 at least partially overlaps the second electrode 12 .

[0042] With this configuration, the first bus bar 20 and the second electrode 12 can be insulated more reliably.

[0043] The heat resistance temperature of capacitor element 10 is 120° C. or higher.

[0044] With this configuration, even if heat is transferred from first bus bar 20 and second bus bar 30 to capacitor element 10, damage to capacitor element 10 due to heat can be suppressed, making it possible to provide a highly heat-resistant capacitor module 100.

[0045] The insulating member 40 is formed of a plate-like resin.

[0046] With this configuration, it is possible to provide a capacitor module 100 that can withstand high voltages.

[0047] [Modification] In the above-described embodiment, the connecting portion 25 is disposed along the end surface 41a of the first insulating portion 41, but the present invention is not limited to this.

[0048] Fig. 4 is a cross-sectional view schematically showing a capacitor module 100A according to a first modification of the first embodiment. Fig. 5 is an enlarged view of a region R2 in Fig. 4. In the capacitor module 100A according to the first modification, the shape of the first bus bar 120 differs from that of the capacitor module 100 according to the first embodiment.

[0049] 4 and 5 , connection portion 125 connecting first extension portion 122 and second extension portion 123 of first bus bar 120 is disposed so as to be inclined with respect to flat portion 13a of side surface 13 of capacitor element 10. With this configuration, first extension portion 22 and side surface 13 of capacitor element 10 can be brought closer together and easily brought into contact with each other.

[0050] Furthermore, in the above-described embodiment, an example has been described in which the capacitor module 100 includes one capacitor element 10, but the present invention is not limited to this. The capacitor module 100 may include a plurality of capacitor elements 10.

[0051] In the above-described embodiment, an example has been described in which the second extending portion 23 of the first bus bar 20 and the first insulating portion 41 are in contact with each other, but this is not limiting. A gap may be formed between the second extending portion 23 and the first insulating portion 41. Similarly, a gap may be formed between the third extending portion 24 and the second insulating portion 42, and between the fourth extending portion 32 and the second insulating portion 42.

[0052] In the above-described embodiment, the second bus bar 30 has a flat plate shape, but the present invention is not limited to this. The second bus bar 30 may have a curved shape similar to the first bus bar 20.

[0053] (Summary of the embodiment) (1) A capacitor module according to the present disclosure includes one or more capacitor elements each having a first electrode, a second electrode, and a side surface connecting the first electrode and the second electrode, a first bus bar electrically connected to the first electrode, a second bus bar electrically connected to the second electrode, an insulating member insulating the first bus bar from the second bus bar, a case accommodating at least one or more capacitor elements, and a sealing resin filled in the case, wherein the insulating member is a member that electrically connects the second electrode to the first electrode. The first busbar has a first contact portion in contact with the first electrode, a first extension portion extending along the side surface, a second extension portion extending along the first insulating portion, and a third extension portion extending along the second insulating portion, and the second busbar has a second contact portion in contact with the second electrode and a fourth extension portion extending along the second insulating portion, and the first extension portion is positioned closer to the side surface than the second extension portion.

[0054] (2) In the capacitor module of (1), the first bus bar may have a connection portion that extends in a direction intersecting the side surface so as to connect the first extension portion and the second extension portion.

[0055] (3) In the capacitor module of (1) or (2), the first extension may be in contact with the side surface.

[0056] (4) In the capacitor module of any one of (1) to (3), the first insulating portion may at least partially overlap the second electrode.

[0057] (5) In the capacitor module of any one of (1) to (4), the heat-resistant temperature of the capacitor element may be 120° C. or higher.

[0058] (6) In the capacitor module of any one of (1) to (5), the insulating member may be formed of a plate-shaped resin.

[0059] The present disclosure is useful for capacitor modules used in various electronic devices, electrical devices, industrial devices, vehicle devices, etc.

[0060] REFERENCE SIGNS LIST 10 Capacitor element 11 First electrode 12 Second electrode 13 Side surface 20, 120 First bus bar 21 First contact portion 22, 122 First extension portion 23, 123 Second extension portion 24 Third extension portion 25, 125 Connection portion 30 Second bus bar 31 Second contact portion 32 Fourth extension portion 40 Insulating member 41 First insulating portion 42 Second insulating portion 50 Case 60 Sealing resin 100, 100A Capacitor module

Claims

1. A capacitor comprising: one or more capacitor elements each having a first electrode, a second electrode, and a side surface connecting the first electrode and the second electrode; a first bus bar electrically connected to the first electrode; a second bus bar electrically connected to the second electrode; an insulating member insulating the first bus bar and the second bus bar; a case accommodating at least the one or more capacitor elements; and a sealing resin filled in the case; wherein the insulating member has a first insulating portion extending along the side surface in a direction from the second electrode to the first electrode and a second insulating portion extending along the second bus bar; the first bus bar has a first contact portion in contact with the first electrode, a first extension portion extending along the side surface, a second extension portion extending along the first insulating portion, and a third extension portion extending along the second insulating portion; and the second bus bar has a second contact portion in contact with the second electrode and a fourth extension portion extending along the second insulating portion, the first extension portion is disposed at a position closer to the side surface than the second extension portion.

2. The capacitor module according to claim 1, wherein the first bus bar has a connection portion extending in a direction intersecting the side surface so as to connect the first extension portion and the second extension portion.

3. The capacitor module according to claim 1 or 2, wherein the first extension portion is in contact with the side surface.

4. The capacitor module according to claim 1, wherein the first insulating portion at least partially overlaps the second electrode.

5. The capacitor module according to any one of claims 1 to 4, wherein the heat resistance temperature of the capacitor element is 120°C or higher.

6. The capacitor module according to any one of claims 1 to 5, wherein the insulating member is formed from a plate-shaped resin.

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