Power conversion device

Abstract

The present application provides a power conversion device capable of improving the cooling effect of a capacitor. The power conversion device has: a capacitor having first and second terminal electrodes facing each other; a power module having a power semiconductor element; a terminal base for electrically connecting the capacitor and the power module to each other; first and second bus bars connecting the first and second terminal electrodes and the terminal base, respectively; and a board member on which the capacitor, the power module, and the terminal base are placed and which has a flow path of a cooling medium that cools the capacitor and the terminal base, the capacitor having the first terminal electrode facing the flow path side and the second terminal electrode facing the opposite side of the flow path, the terminal base having a first connecting portion connected to the first bus bar and a second connecting portion connected to the second bus bar, and having a higher thermal conductivity between the capacitor and the flow path than the first connecting portion.

Description

Technical Field

[0001] This invention relates to power conversion devices. Background Technology

[0002] Regarding power conversion devices, for example, Patent Document 1 describes a method of mounting a capacitor having a pair of opposing end-face electrodes and a semiconductor module connected to the capacitor via a bus bar on a cooler. The capacitor is mounted on the cooler with one end-face electrode facing the cooler side and the other end-face electrode facing the side opposite to the cooler.

[0003] Existing technical documents

[0004] Patent Document 1: Japanese Patent Application Publication No. 2017-139886 Summary of the Invention

[0005] The problem that the invention aims to solve

[0006] In a capacitor, the region near the end electrode on the side opposite to the cooler is farther from the cooler than the region near the end electrode on the cooler side, and therefore may not achieve a sufficient cooling effect.

[0007] Therefore, the present invention was made in view of the above-mentioned problems, and its object is to provide a power conversion device that can improve the cooling effect of capacitors.

[0008] Methods for solving problems

[0009] The power conversion device of the present invention comprises: a capacitor having a first terminal electrode and a second terminal electrode facing each other; a power module having one or more power semiconductor elements; a terminal block for electrically connecting the capacitor and the power module to each other; a first busbar connecting the first terminal electrode and the terminal block; a second busbar connecting the second terminal electrode and the terminal block; and a plate member that holds the capacitor, the power module and the terminal block, and has a flow path for a cooling medium to cool the capacitor and the terminal block, wherein the first terminal electrode of the capacitor faces the flow path side, and the terminal block has: a first connecting portion connected to the first busbar; and a second connecting portion connected to the second busbar, wherein the second connecting portion provides higher thermal conductivity between the capacitor and the flow path compared to the first connecting portion.

[0010] In the power conversion device described above, the connection position between the second connection part and the second busbar may be closer to the flow path than the connection position between the first connection part and the first busbar.

[0011] In the power conversion device described above, the first nut may be embedded in the first connecting part such that the axial end face of the first nut that is fastened to the first busbar by bolts faces the flow path, and the second nut may be embedded in the second connecting part such that the axial end face of the second nut that is fastened to the second busbar by bolts faces the flow path, wherein the area of ​​the end face of the second nut is larger than the area of ​​the end face of the first nut.

[0012] In the power conversion device described above, the first nut may be embedded in the first connecting part such that the axial end face of the first nut that is fastened to the first busbar by bolts faces the flow path; and the second nut may be embedded in the second connecting part such that the axial end face of the second nut that is fastened to the second busbar by bolts faces the flow path, wherein the thermal conductivity of the second nut is higher than that of the first nut.

[0013] In the aforementioned power conversion device, it is also possible that: in the first connecting portion, the first nut is embedded such that the axial end face of the first nut, which is fastened to the first busbar by bolts, faces the flow path, and a first piece of material is provided between the end face of the first nut and the plate surface of the plate member; in the second connecting portion, the second nut is embedded such that the axial end face of the second nut, which is fastened to the second busbar by bolts, faces the flow path, and a second piece of material is provided between the end face of the second nut and the plate surface of the plate member, wherein the thermal conductivity of the second piece of material is higher than that of the first piece of material.

[0014] The effects of the invention

[0015] According to the present invention, the cooling effect of capacitors can be improved in power conversion devices. Attached Figure Description

[0016] Figure 1 This is a plan view showing an example of a power conversion device from a top-down perspective.

[0017] Figure 2 It is a diagram that roughly shows the circuit structure of the power conversion device.

[0018] Figure 3 It is along Figure 1 A partial sectional view of line AA.

[0019] Figure 4 This is a plan view showing an example of the cooling water flow path from a top-down perspective.

[0020] Figure 5 It is along Figure 1A partial sectional view of the BB line.

[0021] Figure 6 (A) is along Figure 1 A partial sectional view of the CC line. Figure 6 (B) is a plan view of an example of the lower surface of the terminal block in a frontal (or frontal) view. Detailed Implementation

[0022] (Structure of the power conversion device)

[0023] Figure 1 This is a plan view showing an example of the power conversion device 1 from a top view. Furthermore, in Figure 1 The following diagrams show the mutually orthogonal X, Y, and Z directions.

[0024] The power conversion device 1 includes a frame 10, a film capacitor 11, a terminal block 12, a terminal block 16, a negative-side busbar 13, a positive-side busbar 14, a power module 15, and a terminal holding part 17. The power conversion device 1 is used, for example, as a power control unit for electric vehicles and hybrid vehicles. Furthermore, illustrations of the upper cover, control board, noise filter, and wiring harness of the power conversion device 1 are omitted.

[0025] The frame 10 is a generally rectangular plate member. A film capacitor 11, terminal blocks 12 and 16, a power module 15, and a terminal holding part 17 are mounted on the plate surface 10a of the frame 10. A cooling water flow path, described later, is provided inside the frame 10. Thus, the frame 10 cools the film capacitor 11, terminal blocks 12 and 16, the power module 15, and the terminal holding part 17. Furthermore, the frame 10 is formed of a metal with high rigidity and thermal conductivity.

[0026] The film capacitor 11 is an example of a capacitor. The film capacitor 11 has positive and negative terminal electrodes connected to the positive-side busbar 14 and the negative-side busbar 13, respectively. The ends 14a and 13a of the positive-side busbar 14 and the negative-side busbar 13 are located on the outer side of the positive side of the frame 10 in the Y direction, and are electrically connected to the positive and negative terminals of an external battery (not shown), respectively. The positive-side busbar 14 and the negative-side busbar 13 are formed, for example, of a highly conductive metal such as copper.

[0027] An insulating member 18 for short-circuit prevention is maintained between the positive-side busbar 14 and the negative-side busbar 13. The positive-side busbar 14, sandwiching the insulating member 18, is positioned on the positive side (upper part) of the negative-side busbar 13 in the Z direction. The positive-side busbar 14 and the negative-side busbar 13 are bent towards the positive side in the X direction from their respective ends 14a and 13a, and extend towards the negative side in the Y direction from their bent portions between the power module 15 and the film capacitor 11. The portions of the positive-side busbar 14 and the negative-side busbar 13 extending along the Y direction branch towards the terminal electrode of the film capacitor 11 on the positive side in the X direction and the terminal block 12 on the negative side in the X direction, respectively.

[0028] Power module 15 incorporates one or more power semiconductor elements 150. The power semiconductor element 150 is, for example, an intelligent power module (IPM). An IPM includes switching elements such as IGBTs (Insulated Gate Bipolar Transistors) and return diodes connected in parallel with the switching elements. In this example, six power semiconductor elements 150 function as an inverter for power conversion. Power module 15 is electrically connected to the positive-side busbar 14 and the negative-side busbar 13 at one terminal block 12, and to connection terminals 171u, 171v, and 171w at the other terminal block 16.

[0029] The terminal holding part 17 holds two sets of rectangular, flat connecting terminals 171u, 171v, and 171w on the upper part of the frame 10. The connecting terminals 171u, 171v, and 171w are connected to an external motor (not shown) and extend parallel to the negative end of the frame 10 in the X direction to the terminal block 16. On the other hand, the power module 15 has six terminals 153 extending to the terminal block 16. Each terminal 153 is connected to the connecting terminals 171u, 171v, and 171w respectively on the terminal block 16 by bolts 80.

[0030] Furthermore, the power module 15 has three sets of positive terminals 152 and negative terminals 151 extending in the X direction to the terminal block 12 opposite to the terminal block 16. The positive terminals 152 and negative terminals 151 are arranged alternately in the Y direction. Additionally, the terminal block 12 has three sets of positive-side connection portions 122 and negative-side connection portions 121. The positive-side connection portions 122 and negative-side connection portions 121 are arranged alternately in the Y direction. The positive-side connection portion 122 is connected to the positive-side busbar 14, and the negative-side connection portion 121 is connected to the negative-side busbar 13. Furthermore, the positive-side connection portion 122 is an example of a first connection portion, and the negative-side connection portion 121 is an example of a second connection portion.

[0031] The positive-side busbar 14 and the negative-side busbar 13 branch out in two directions: towards the terminal block 12 and towards the film capacitor 11, respectively. The positive-side busbar 14 and the negative-side busbar 13 each have three connecting terminals 140 and 130 extending to the terminal block 12. Connecting terminal 140 and the positive terminal 152 are fastened to the positive-side connecting portion 122 by bolts 90, and connecting terminal 130 and the negative terminal 151 are fastened to the negative-side connecting portion 121 by bolts 90. Thus, the terminal block 12 is used to electrically connect the film capacitor 11 and the power module 15.

[0032] Figure 2 This is a schematic diagram showing the circuit structure S of the power conversion device 1. The power conversion device 1 is connected between a battery E, such as a lithium-ion battery, and a motor MG. The motor MG is used, for example, as a drive source for a vehicle. The end 14a of the positive side busbar 14 is connected to the positive terminal of the battery E, and the end 14a of the negative side busbar 13 is connected to the negative terminal of the battery E. In addition, the connection terminals 171u, 171v, and 171w are connected to the three-phase coils Lu, Lv, and Lw of the motor MG, respectively.

[0033] Power module 15 includes an inverter INV. The inverter INV is connected in parallel with the film capacitor 11 and the battery E via the positive side connection 122 and the negative side connection 121 of terminal block 12. The inverter INV has upper arm-side switching elements SW1u, SW1v, SW1w corresponding to 3, and lower arm-side switching elements SW2u, SW2v, SW2w. The upper arm-side switching elements SW1u, SW1v, SW1w and the lower arm-side switching elements SW2u, SW2v, SW2w are connected in series. A rectifier diode Di is connected to each switching element SW1u, SW1v, SW1w, SW2u, SW2v, SW2w. The switching elements SW1u, SW1v, SW1w, SW2u, SW2v, SW2w and the rectifier diode Di are included in the power semiconductor element 150.

[0034] Each switching element SW1u, SW1v, SW1w, SW2u, SW2v, and SW2w is controlled to switch on and off by a PWM (Pulse Width Modulation) signal from a control board not shown. Thus, the DC current input from the battery E to the inverter INV is converted into three-phase AC current and output to the motor MG.

[0035] The film capacitor 11 is connected in parallel with respect to both the battery E and the inverter INV. The positive-side busbar 14 connects the positive terminal of the battery E, the positive-side terminal electrode of the film capacitor 11, and the positive-side connection portion 122 of the terminal block 12. The negative-side busbar 13 connects the negative terminal of the battery E, the negative-side terminal electrode of the film capacitor 11, and the negative-side connection portion 121 of the terminal block 12. In the positive-side busbar 14 and the negative-side busbar 13, the DC component Id of the current flowing between the battery E and the inverter INV, and the ripple component Ia of the current flowing between the two terminals of the film capacitor 11, are present. The film capacitor 11 smooths the voltage across the inverter INV.

[0036] Figure 3 It is along Figure 1 A partial sectional view along line AA. Figure 3 In the middle, to and Figure 1 Common structural elements are labeled with the same reference numerals, and their descriptions are omitted. Inside the frame 10, a cooling water flow path 100 is provided along the plate surface 10a. The film capacitor 11 includes a capacitor element 110, a positive terminal electrode 112, a negative terminal electrode 111, and a housing 113. Furthermore, the plate surface 10a of the frame 10 has a height difference such that the mounting position of the film capacitor 11 in the Z direction is lower than the mounting positions of the terminal block 12 and the power module 15.

[0037] The capacitor element 110 is formed by winding a resin film coated with aluminum. The positive-side terminal electrode 112 and the negative-side terminal electrode 111 are end-face electrodes, such as those produced by metal sputtering. In the Z-direction, the negative-side terminal electrode 111 is disposed on the upper surface of the capacitor element 110, and the positive-side terminal electrode 112 is disposed on the lower surface of the capacitor element 110. The positive-side terminal electrode 112 and the negative-side terminal electrode 111 sandwich the capacitor element 110 and face each other in the Z-direction.

[0038] Thus, the film capacitor 11 is mounted on the frame 10 with the positive electrode 112 facing the flow path 100 of the cooling water and the negative electrode 111 facing the side opposite to the flow path 100. Furthermore, the positive electrode 112 is an example of a first terminal electrode, and the negative electrode 111 is an example of a second terminal electrode. Alternatively, in contrast to this example, the film capacitor 11 may also be mounted on the frame 10 with the negative electrode 111 facing the flow path 100 and the positive electrode 112 facing the opposite side. In this case, the positive electrode 112 corresponds to the second terminal electrode, the negative electrode 111 corresponds to the first terminal electrode, the positive connection portion 122 corresponds to the second connection portion, and the negative connection portion 121 corresponds to the first connection portion.

[0039] The housing 113 has a generally rectangular box shape with one side open on the terminal block 12 side. A resin 114, referred to as a potting material, is filled between the housing 113 and the capacitor element 110. The housing 113 is formed, for example, of resin, a metal such as aluminum, or a resin coated with aluminum.

[0040] A circum sheet 20 is provided between the lower part of the housing 113 and the plate surface 10a of the frame 10. The circum sheet 20 allows heat from the capacitor element 110 to diffuse to the plate surface 10a of the frame 10. Therefore, the film capacitor 11 is cooled by cooling water via the circum sheet 20.

[0041] Furthermore, an annular plate 21 is provided between the negative electrode side connection portion 121 of the terminal block 12 and the plate surface 10a of the frame 10. The annular plate 21 allows heat from the negative electrode side connection portion 121 to diffuse to the plate surface 10a of the frame 10. The terminal block 12 experiences a temperature rise not only due to the DC component of the current flowing through the positive electrode side busbar 14 and the negative electrode side busbar 13, but also due to the heat conducted from the film capacitor 11 through the positive electrode side busbar 14 and the negative electrode side busbar 13. The heat from the negative electrode side connection portion 121 of the terminal block 12 is cooled by cooling water within the flow path 100 via the annular plate 21. While cooling water is one example of a cooling medium, other fluids may also be used.

[0042] Figure 4 This is a plan view showing an example of the cooling water flow path 100 from above. Figure 4 In the middle, to and Figure 1 Common structures are labeled with the same number, and their descriptions are omitted.

[0043] The flow path 100 has a generally U-shaped form, passing through the lower part of the film capacitor 11, terminal block 12, and power module 15. Reference numeral D indicates the direction of cooling water flow. The inlet 100a and outlet 100b of the flow path 100 are arranged on the positive end face of the frame 10 in the X direction. The inlet 100a and outlet 100b are connected to external pumps, etc.

[0044] Refer again Figure 3 The negative-side busbar 13 includes a connecting terminal 130, an extension 131, and an electrode connection portion 132. The connecting terminal 130 extends from the lower end of the extension 131 in the Z direction toward the negative side in the X direction, and is fastened together with the negative terminal 151 on the power module 15 side to the negative-side connection portion 121 of the terminal block 12 by bolts 90. A nut 91 is embedded inside the negative-side connection portion 121 along the Z direction. By screwing the bolts 90 and the nut 91, the connecting terminal 130 and the negative terminal 151 overlap and are fixed to the negative-side connection portion 121 of the terminal block 12.

[0045] The extension 131 is a plate-shaped member extending positively in the Y direction, held in a position where its surface is approximately orthogonal to the plate surface 10a of the frame 10. The lower end of the extension 131 in the Z direction is connected to the connecting terminal 130, and the upper end of the extension 131 in the Z direction is connected to the electrode connection portion 132. The electrode connection portion 132 extends from the upper end of the extension 131 in the Z direction towards the positive side in the X direction, and connects to the negative electrode side terminal electrode 111 in the Z direction. Thus, the negative electrode side busbar 13 connects the negative electrode side terminal electrode 111 to the terminal block 12.

[0046] A portion of the heat from the film capacitor 11 is cooled by cooling water via the ring plate 20, as indicated by reference numeral Ro. However, another portion of the heat from the film capacitor 11 is cooled by cooling water via the cooling path Ra through the negative-side busbar 13. The cooling path Ra extends from the negative-side terminal electrode 111 through the negative-side busbar 13 to the negative-side connection portion 121 of the terminal block 12. The heat from the film capacitor 11 is conducted in the cooling path Ra and diffuses from the nut 91 within the negative-side connection portion 121 through the ring plate 21 into the flow path 100 inside the frame 10.

[0047] Figure 5 It is along Figure 1 A partial sectional view of the BB line. Figure 5 In the middle, to and Figure 1 Common structures are labeled with the same number, and their descriptions are omitted.

[0048] An annular piece 22 is provided between the positive electrode side connection portion 122 of the terminal block 12 and the plate surface 10a of the frame 10. The annular piece 22 causes the heat of the positive electrode side connection portion 122 to diffuse to the plate surface 10a of the frame 10.

[0049] The positive-side busbar 14 includes a connection terminal 140, an extension 141, and an electrode connection portion 142. The connection terminal 140 extends from the upper end of the extension 141 in the Z direction toward the negative side in the X direction, and is fastened together with the positive terminal 152 on the power module 15 side to the positive-side connection portion 122 of the terminal block 12 by bolts 90. A nut 92 is embedded inside the positive-side connection portion 122 along the Z direction. By screwing the bolts 90 and the nut 92, the connection terminal 140 and the positive terminal 152 overlap and are fixed to the positive-side connection portion 122 of the terminal block 12.

[0050] The extension 141 is a plate-shaped member extending in the Y direction, held in a position where its surface is approximately orthogonal to the plate surface 10a of the frame 10. The upper end of the extension 141 in the Z direction is connected to the connecting terminal 140, and the lower end of the extension 141 in the Z direction is connected to the electrode connection portion 142. The electrode connection portion 142 extends from the lower end of the extension 141 in the Z direction toward the positive side in the X direction, and is connected to the positive electrode side terminal electrode 112 in the Z direction. Thus, the positive electrode side busbar 14 connects the positive electrode side terminal electrode 112 to the terminal block 12.

[0051] A portion of the heat from the film capacitor 11 is cooled by cooling water via a cooling path Rb passing through the positive side busbar 14. The cooling path Rb extends from the positive side terminal electrode 112 through the positive side busbar 14 to the positive side connection portion 122 of the terminal block 12. The heat from the film capacitor 11 is conducted in the cooling path Rb and diffuses from the nut 92 within the positive side connection portion 122 through the ring plate 22 into the flow path 100 inside the frame 10.

[0052] As described above, the positive electrode 112 faces the flow path 100 of the cooling water, and the negative electrode 111 faces the opposite side of the flow path 100. Therefore, in the film capacitor 11, the negative electrode 111 is farther from the flow path 100 than the positive electrode 112. Consequently, during the cooling of the film capacitor 11 via the annular plate 20 at the lower part of the housing 113, the vicinity of the negative electrode 111 of the capacitor element 110 does not receive a cooling effect compared to the vicinity of the positive electrode 112.

[0053] In contrast, the thermal conductivity between the film capacitor 11 and the cooling water flow path 100 in the negative electrode side connection 121 is higher than that in the positive electrode side connection 122. Therefore, the terminal block 12 has a cooling structure in which the cooling path Ra has a higher cooling performance than the cooling path Rb in the cooling of the film capacitor 11. The vicinity of the negative electrode 111 of the capacitor element 110 is cooled better via the cooling path Ra compared to the vicinity of the positive electrode 112. Therefore, the cooling effect of the film capacitor 11 is improved. Examples of the cooling structure of the terminal block 12 are given below.

[0054] (Cooling structure of terminal block)

[0055] Figure 6 (A) is along Figure 1 A partial sectional view of the CC line. Figure 6 (B) is a plan view showing an example of the lower surface 12a of the terminal block 12 from the front view. Figure 6 (A) and Figure 6 In (B), regarding... Figure 3 and Figure 5Common structures are labeled with the same reference numerals, and their descriptions are omitted. Terminal block 12 has the following first to fourth cooling structures.

[0056] [First Cooling Structure]

[0057] In the Z direction, the height H2 of the negative electrode side connection 121 is lower than the height H1 of the positive electrode side connection 122. Therefore, the distance from the connection terminal 130 of the negative electrode side busbar 13 to the flow path 100 is shorter than the distance from the connection terminal 140 of the positive electrode side busbar 14 to the flow path 100. Thus, the first cooling structure is such that the connection position between the negative electrode side connection 121 and the negative electrode side busbar 13 is closer to the flow path 100 than the connection position between the positive electrode side connection 122 and the positive electrode side busbar 14. Therefore, the cooling performance of cooling path Ra is higher than that of cooling path Rb, and the thermal conductivity of the negative electrode side connection 121 is higher than that of the positive electrode side connection 122.

[0058] [Second Cooling Structure]

[0059] A nut 91 is embedded in the negative electrode side connection portion 121, and a nut 92 is embedded in the positive electrode side connection portion 122. Each nut 91 and 92 is embedded such that its axial end faces 91a and 92a face the flow path 100. The negative electrode side busbar 13 is fastened to the nut 91 by bolts 90, and the positive electrode side busbar 14 is fastened to the nut 92 by bolts 90. The second cooling structure is one in which the area of ​​the end face 91a of the nut 91 is larger than the area of ​​the end face 92a of the nut 92. For example, the diameter R1 of the nut 91 is larger than the diameter R2 of the nut 92. Therefore, the thermal conductivity from the nut 91 to the flow path 100 is higher than that from the nut 92 to the flow path 100. Consequently, the cooling performance of the cooling path Ra is higher than that of the cooling path Rb, and the thermal conductivity of the negative electrode side connection portion 121 is higher than that of the positive electrode side connection portion 122. Furthermore, nut 92 is an example of the first nut, and nut 91 is an example of the second nut. In contrast to this example, when the film capacitor 11 is mounted on the frame 10 with the negative terminal electrode 111 facing the flow path 100 side and the positive terminal electrode 112 facing the opposite side, nut 92 is equivalent to the second nut, and nut 91 is equivalent to the first nut.

[0060] [Third Cooling Structure]

[0061] The third cooling structure is one in which the thermal conductivity of nut 91 is higher than that of nut 92. For example, nut 91 is made of copper, and nut 92 is made of iron. Therefore, the thermal conductivity from nut 91 to flow path 100 is higher than that from nut 92 to flow path 100. Consequently, the cooling performance of cooling path Ra is higher than that of cooling path Rb, and the thermal conductivity of negative electrode side connection 121 is higher than that of positive electrode side connection 122.

[0062] [Fourth Cooling Structure]

[0063] The fourth cooling structure is one in which the thermal conductivity of ring 21 is higher than that of ring 22. Ring 21 is sandwiched between the end face 91a of nut 91 and the plate face 10a of frame 10, and ring 22 is sandwiched between the end face 92a of nut 92 and the plate face 10a of frame 10. Rings 21 and 22 are formed of resins such as silicon and olefins. Inorganic fillers such as boron nitride and alumina are added to one of the rings 21. Therefore, the thermal conductivity of ring 21 is higher than that of ring 22.

[0064] Therefore, the thermal conductivity from nut 91 to flow path 100 is higher than that from nut 92 to flow path 100. Consequently, the cooling performance of cooling path Ra is higher than that of cooling path Rb, and the thermal conductivity of negative electrode side connection 121 is higher than that of positive electrode side connection 122. Furthermore, ring 22 is an example of a first component, and ring 21 is an example of a second nut. Conversely, in the case where the film capacitor 11 is mounted on the frame 10 with the negative electrode side terminal electrode 111 facing the flow path 100 side and the positive electrode side terminal electrode 112 facing the opposite side, ring 22 corresponds to the second nut, and ring 21 corresponds to the first nut.

[0065] Furthermore, terminal block 12 does not necessarily need to have all of the first to fourth cooling structures; having at least one of the first to fourth cooling structures is sufficient. In addition, in order to suppress heat generation caused by the DC component of the current, the cross-sectional area of ​​the connection terminal 130 of the negative side busbar 13 may be larger than the cross-sectional area of ​​the connection terminal 140 of the positive side busbar 14.

[0066] The above-described embodiments are preferred embodiments of the present invention. However, they are not limited thereto, and various modifications can be made without departing from the spirit of the present invention.

Claims

1. A power conversion device, comprising: A capacitor having a first terminal electrode and a second terminal electrode that are opposite to each other; A power module having one or more power semiconductor elements; Terminal block, which is used to electrically connect the capacitor to the power module; A first busbar connects the first terminal electrode to the terminal block; The second busbar connects the second terminal electrode to the terminal block; as well as A plate component that houses the capacitor, the power module, and the terminal block, and has a flow path for a cooling medium to cool the capacitor and the terminal block. The capacitor is mounted on the plate member with its first terminal electrode facing the flow path side and its second terminal electrode facing the side opposite to the flow path. The terminal block has: A first connecting portion, which is connected to the first busbar; and The second connection portion, which is connected to the second busbar, provides higher thermal conductivity between the capacitor and the flow path compared to the first connection portion.

2. The power conversion device according to claim 1, The connection position between the second connecting part and the second busbar is closer to the flow path than the connection position between the first connecting part and the first busbar.

3. The power conversion device according to claim 1, In the first connecting portion, the first nut is embedded such that the axial end face of the first nut for fastening the first busbar by bolts faces the flow path. In the second connecting portion, the second nut is embedded such that the axial end face of the second nut for fastening the second manifold by bolts faces the flow path. The area of ​​the end face of the second nut is larger than the area of ​​the end face of the first nut.

4. The power conversion device according to claim 1, In the first connecting portion, the first nut is embedded such that the axial end face of the first nut for fastening the first busbar by bolts faces the flow path. In the second connecting portion, the second nut is embedded such that the axial end face of the second nut for fastening the second manifold by bolts faces the flow path. The thermal conductivity of the second nut is higher than that of the first nut.

5. The power conversion device according to claim 1, In the first connecting portion, the first nut is embedded such that the axial end face of the first nut for fastening the first busbar with bolts faces the flow path, and a first piece of material is provided that is sandwiched between the end face of the first nut and the plate surface of the plate member. In the second connecting portion, the second nut is embedded such that the axial end face of the second nut for fastening the second busbar by bolts faces the flow path, and a second piece is provided between the end face of the second nut and the plate surface of the plate member. The thermal conductivity of the second component is higher than that of the first component.

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