Capacitor module

Abstract

This capacitor module comprises: a plurality of capacitive elements each having a bottom surface and side surfaces, with a positive electrode terminal and a negative electrode terminal provided on an upper surface side, which is the surface opposite the bottom surface; a positive electrode busbar connected to the positive electrode terminal; a negative electrode busbar connected to the negative electrode terminal; and a conductive metal partition connected to a ground potential and facing the positive electrode busbar and the negative electrode busbar across an insulating member, wherein the positive electrode busbar and the negative electrode busbar are provided opposite the bottom surface and the side surfaces of the capacitive element, with the metal partition interposed therebetween.

Description

Capacitor Module

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

[0002] For example, Patent Document 1 listed below discloses a technology for suppressing the inductance value of a bus bar by arranging parts of the bus bars facing each other with a metal partition between them, thereby causing currents to flow in opposite directions.

[0003] JP 2014-27768 A

[0004] In view of the technology described in Patent Document 1, an object of the present invention is to provide a capacitor module configured to suppress noise generated from an inverter and improve the heat dissipation of inverter components that occurs as the inverter voltage and current increase.

[0005] The capacitor module has a bottom surface and side surfaces, and includes a plurality of capacitor elements each having a positive terminal and a negative terminal on the top surface opposite the bottom surface, a positive bus bar connected to the positive terminal, a negative bus bar connected to the negative terminal, and a conductive metal partition wall connected to ground potential and facing the positive bus bar and the negative bus bar via an insulating member, with the positive bus bar and the negative bus bar facing the bottom surface and the side surface of the capacitor element, with the metal partition wall sandwiched between them.

[0006] It is possible to provide a capacitor module that reduces noise and improves heat dissipation.

[0007] FIG. 6 is a top view of the positive and negative bus bars according to one embodiment of the present invention; FIG. 7 is a structural diagram of the metal partition wall according to one embodiment of the present invention; FIG. 8 is a structural diagram of the metal partition wall according to one embodiment of the present invention;

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The following description and drawings are examples for explaining the present invention, and some omissions and simplifications have been made as appropriate for clarity of explanation. The present invention can be implemented in various other forms. Unless otherwise specified, each component may be singular or plural.

[0009] In order to facilitate understanding of the invention, the position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings.

[0010] (One embodiment and overall configuration) (FIG. 1) A capacitor module 1 is mounted on a power conversion device (not shown). The capacitor module 1 is electrically connected to a DC battery (not shown) and an inverter circuit (power module) in the power conversion device. The capacitor module 1 has a capacitor element 2, a metal partition wall 3, a positive bus bar 4, a negative bus bar 5, and an insulating member 6.

[0011] The capacitor elements 2 suppress ripples in the DC voltage in the power conversion device. The four capacitor elements 2 shown in the figure are electrically connected in parallel. Each capacitor element 2 has a bottom surface and side surfaces, and on the top surface opposite the bottom surface, it has a positive terminal 21 that is a terminal for electrically connecting to the positive bus bar 4 and a negative terminal 22 that is a terminal for connecting to the negative bus bar 5.

[0012] The metal partition wall 3 is conductive and has a ground portion 31, a connection terminal 32, and a metal protrusion 33. A plurality of ground portions 31 are provided on the metal partition wall 3, and are provided on both ends and the center of the bottom surface of the metal partition wall 3. The connection terminals 32 are terminals for fixing the metal partition wall 3 to an insulating member 6 (described later) with screws, and have a shape that protrudes outward from the metal partition wall 3.

[0013] The capacitor elements 2 are arranged in a housing space 3a formed by the metal partition wall 3, and are fixed in place by filling the housing space 3a with a potting resin or the like.

[0014] The positive bus bar 4 has, at its upper part, a capacitor connection terminal 41 which is a terminal for connecting to the capacitor element 2. The positive bus bar 4 also has, at its lower part, an output terminal 42 which is connected to the inverter circuit side and an input terminal 43 which is connected to the DC battery side, as shown in FIG. 3 described later. Similarly, the negative bus bar 5 has, at its upper part, a capacitor connection terminal 51 which is a terminal for connecting to the capacitor element 2. The negative bus bar 5 has, at its lower part, an output terminal 52 which is connected to the inverter circuit side and an input terminal 53 which is connected to the DC battery side, as shown in FIG. 3 described later.

[0015] Note that the above-described configuration of the input terminals and output terminals is one example, and when applied to, for example, a rectifier circuit or a bidirectional inverter circuit, terminals 42 and 52 may be used as input terminals, and terminals 43 and 53 may be used as output terminals.

[0016] The insulating member 6 has a connection terminal 61 that protrudes outward from the insulating member 6. The connection terminal 61 is connected and fixed to the connection terminal 32 by screws.

[0017] As shown in the drawings (FIGS. 2 and 3), the positive bus bar 4 and the negative bus bar 5 are insert-molded inside the insulating member 6, and are thereby formed as an integral member with the insulating member 6. In this way, the insulating member 6 not only functions to electrically insulate the positive bus bar 4 and the negative bus bar 5, but also improves assembly by fixing and integrating other members.

[0018] The positive bus bar 4 and the negative bus bar 5 are disposed on the outer side of the metal partition wall 3. The positive bus bar 4 and the negative bus bar 5 face the bottom surface and side surface of the capacitor element 2, with the metal partition wall 3 sandwiched therebetween. Specifically, a first side surface 2a of the capacitor element 2 faces the side surface 4a of the positive bus bar 4, and a second side surface 2b of the capacitor element 2, which faces the first side surface 2a, faces the side surface 5a of the negative bus bar 5.

[0019] The metal partition wall 3 faces the positive bus bar 4 and the negative bus bar 5 via the insulating member 6, and is arranged between the capacitor element 2 and the positive bus bar 4 and the negative bus bar 5, thereby generating parasitic capacitance.

[0020] A plurality of grounding portions 31 are provided at predetermined intervals on the bottom surface of the metal partition wall 3. Of the grounding portions 31 provided on the bottom surface of the metal partition wall 3, the grounding portions 31 provided at both ends of the bottom surface are connection portions for fixing the metal partition wall 3 to a housing of a power conversion device (not shown) with screws. As a result, the metal partition wall 3 is connected to the ground potential via the housing (not shown).

[0021] The generated parasitic capacitance has the same function as a Y capacitor provided between the positive bus bar 4, the negative bus bar 5, and the housing, because the metal partition wall 3 is connected to the housing of the power conversion device (not shown) via the grounding part 31. In other words, a low impedance path for noise current can be established without adding a new Y capacitor to the power conversion device, which not only improves EMC performance and suppresses high-frequency noise, but also contributes to cost reduction and space savings.

[0022] In addition, by doing this, heat from the positive bus bar 4 and the negative bus bar 5 can more easily flow to the housing of the power conversion device through the metal partition wall 3, thereby improving the heat dissipation properties of the capacitor element 2 and the positive bus bar 4 and the negative bus bar 5.

[0023] The positive bus bar 4 and the negative bus bar 5 may be arranged inside the insulating member 6 so as to narrow the gap between them and the metal partition wall 3, in order to form a higher parasitic capacitance between them and the metal partition wall 3. In addition, the number of grounding portions 31 on the bottom surface of the metal partition wall 3 may be increased to enhance the effect of reducing impedance.

[0024] The input terminals 43 and 53 are arranged on one side surface of the metal partition wall 3. The output terminals 42 and 52 are arranged on the side surface of the metal partition wall 3 opposite to the side surface on which the input terminals 43 and 53 are arranged.

[0025] The positive bus bar 4 has a side surface 4a and a bottom surface 4b. The negative bus bar 5 has a side surface 5a and a bottom surface 5b. The bottom surfaces 4b and 5b are arranged so as to be separated by a grounding portion 31 provided in the center of the bottom surface of the metal partition wall 3. This configuration ensures that the positive bus bar 4 and the negative bus bar 5 have the same bus bar area, thereby not only reducing noise but also preventing localized heat generation.

[0026] (FIGS. 4 to 7) The input terminals 43, 53 are electrically connected to a DC bus bar connected to a DC battery (not shown). The multiple output terminals 42, 52 are electrically connected to U-phase, V-phase, and W-phase power modules (not shown), respectively. Note that the electrical connection to the power modules is not limited to a direct connection configuration, and may be via another bus bar, and the connection configuration is not particularly limited.

[0027] As shown in the figure, by combining the positive bus bar 4 and the negative bus bar 5, a predetermined gap 7 is formed in the center. The formation of the gap 7 allows the grounding portion 31 ( FIG. 3 ) formed in the center of the metal partition wall 3 to pass through the gap 7, thereby electrically connecting the metal partition wall 3 to the housing of the power conversion device (not shown) via the grounding portion 31, and thus enabling connection to the ground potential.

[0028] The shapes of the positive bus bar 4 and the negative bus bar 5 are not limited to the illustrated example, and may be, for example, such that the bottom surfaces 4 b and 5 b are each formed in a comb-like shape and the comb teeth are arranged alternately. This allows a plurality of gaps 7 to be provided between the bottom surfaces 4 b and 5 b on the bottom surface of the metal partition wall 3, thereby increasing the number of grounding portions 31 on the metal partition wall 3.

[0029] (FIG. 8) In the metal partition wall 3, the connection terminal 32 has a connection hole 321. The connection hole 321 is a connection hole for connecting and fixing the metal partition wall 3 and the insulating member 6, and the metal partition wall 3 and the insulating member 6 are connected and fixed by aligning the connection hole 321 with a hole in the connection terminal 61 and inserting a screw.

[0030] (Figure 9) The grounding parts 31 formed on both ends of the bottom surface of the metal partition wall 3 each have a connection hole 311, and by inserting a screw into the connection hole 311, the metal partition wall 3 and the housing of the power conversion device (not shown) are connected and fixed.

[0031] By providing multiple grounding portions 31, the heat from the positive bus bar 4 and the negative bus bar 5 can be dissipated to a housing not shown, so that the thermal resistance can be parallelized to reduce heat generation and achieve low impedance.

[0032] (FIGS. 10 and 11) A plurality of metal protrusions 33 are formed in the accommodation space 3a formed by the metal partition wall 3. The plurality of metal protrusions 33 are provided at predetermined equal intervals so as to evenly arrange the plurality of capacitor elements 2. With this configuration, the heat transfer areas of the capacitor elements 2 can be made uniform and the heat dissipation area of ​​the capacitor elements 2 can be increased.

[0033] According to the embodiment of the present invention described above, the following advantageous effects are achieved.

[0034] (1) A capacitor module 2 includes a plurality of capacitor elements 2 having a bottom surface and side surfaces, with positive terminals 21 and negative terminals 22 provided on the top surface opposite the bottom surface, a positive bus bar 4 connected to the positive terminals 21, a negative bus bar 5 connected to the negative terminals 22, and a conductive metal partition wall 3 connected to ground potential and facing the positive bus bar 4 and the negative bus bar 5 via an insulating member 6, wherein the positive bus bar 4 and the negative bus bar 5 are disposed opposite the bottom surface and side surface of the capacitor elements 2 with the metal partition wall 3 sandwiched therebetween. This configuration makes it possible to provide a capacitor module 1 that achieves reduced inductance and improved heat dissipation.

[0035] (2) The side surfaces of the capacitor element 2 include a first side surface 2a and a second side surface 2b that faces the first side surface 2a in the capacitor element 2, and the first side surface 2a faces the positive bus bar 4, and the second side surface 2b faces the negative bus bar 5. This allows the bus bar areas to be uniform.

[0036] (3) The positive bus bar 4 and the negative bus bar 5 each have a capacitor connection terminal at their upper part that connects to the capacitor element 2, and a bus bar connection terminal for input / output at their lower part. This contributes to the balance of the bus bar area of ​​the positive bus bar 4 and the negative bus bar 5.

[0037] (4) The metal partition wall 3 has a ground portion 31 on the bottom surface of the metal partition wall 3 that connects the metal partition wall 3 to the ground potential. This contributes to reducing inductance and improving heat dissipation.

[0038] (5) A plurality of grounding portions 31 are provided at predetermined intervals on the bottom surface of the metal partition wall 3. This allows the thermal resistances to be connected in parallel, thereby reducing heat generation and achieving low impedance.

[0039] (6) The metal partition wall 3 has a plurality of metal protrusions 33 in the space 3a that accommodates a plurality of capacitor elements 2. This makes it possible to achieve a uniform heat transfer area and an increased heat dissipation area.

[0040] The present invention is not limited to the above-described embodiments, and various modifications and combinations of other configurations are possible without departing from the spirit of the present invention. Furthermore, the present invention is not limited to those having all of the configurations described in the above-described embodiments, and includes those in which some of the configurations are omitted.

[0041] REFERENCE SIGNS LIST 1 Capacitor module 2 Capacitor element 2a First side surface 2b Second side surface 21 Positive electrode terminal 22 Negative electrode terminal 3 Metal partition wall 3a Storage space 31 Grounding portion 32 Connection terminal between metal partition wall and insulating member 33 Metal protrusion 4 Positive electrode bus bar 4a Positive electrode bus bar side surface 4b Positive electrode bus bar bottom surface 41 Capacitor connection terminal 42 Bus bar connection terminal (output terminal) 43 Bus bar connection terminal (input terminal) 5 Negative electrode bus bar 5a Negative electrode bus bar side surface 5b Negative electrode bus bar bottom surface 51 Capacitor connection terminal 52 Bus bar connection terminal (output terminal) 53 Bus bar connection terminal (input terminal) 6 Insulating member 61 Connection terminal between insulating member and metal partition wall 7 Spacing

Claims

1. A capacitor module comprising: a plurality of capacitor elements each having a bottom surface and a side surface, with positive and negative terminals provided on an upper surface opposite the bottom surface; a positive bus bar connected to the positive terminals; a negative bus bar connected to the negative terminals; and a conductive metal partition wall connected to ground potential and facing the positive and negative bus bars via an insulating member, wherein the positive and negative bus bars are disposed opposite the bottom and side surfaces of the capacitor elements, with the metal partition wall sandwiched therebetween.

2. The capacitor module according to claim 1, wherein the side surface has a first side surface and a second side surface that faces the first side surface in the capacitor element, the first side surface facing the positive bus bar, and the second side surface facing the negative bus bar.

3. The capacitor module according to claim 1, wherein the positive bus bar and the negative bus bar each have a capacitor connection terminal at their upper part that connects to the capacitor element, and a bus bar connection terminal for input / output at their lower part.

4. The capacitor module according to claim 1, wherein the metal partition wall has a grounding portion on the bottom surface of the metal partition wall that connects the metal partition wall to the ground potential.

5. The capacitor module according to claim 4, wherein a plurality of the grounding portions are provided at predetermined intervals on the bottom surface of the metal partition wall.

6. The capacitor module according to claim 1, wherein the metal partition wall has a plurality of metal protrusions in the space that houses the plurality of capacitor elements.

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