Electric device

Abstract

To provide an electric device improved in cooling performance.SOLUTION: A power conversion device as an electric device includes a main terminal 32P forming an energization path, and a P bus bar 52P forming the energization path together with a first bus bar. The main terminal 32P correspond to the first bus bar, and the P bus bar 52P corresponds to a second bus bar. The electric device further includes a fastening member 80 for fastening the first bus bar and the second bus bar to each other, and a cooling member 90 for cooling heat generated in the first bus bar and the second bus bar due to energization. The cooling member 90 is in contact with both the first bus bar and the fastening member 80.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The disclosure in this specification relates to an electrical device including a bus bar that forms an energization path.

Background Art

[0002] Patent Document 1 describes a bus bar that forms an energization path, which is a pair of bus bars fastened with bolts and nuts. The nut is cooled by a heat sink.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] To cool the heat generated in the bus bar during energization, it is not sufficient to only cool the nut, and there is room for improvement in the cooling structure described in Patent Document 1.

[0005] One disclosed object is to provide an electrical device with improved cooling performance.

Means for Solving the Problems

[0006] To achieve the above object, in an "electrical device" according to one aspect of the present disclosure, a first bus bar (32P, 32N) that forms an energization path, a second bus bar (52P, 52N) that forms an energization path together with the first bus bar, a fastening member (80) that fastens the first bus bar and the second bus bar to each other, and a cooling member (90) that cools the heat generated in the first bus bar and the second bus bar during energization, are provided, and the cooling member is in contact with both the first bus bar and the fastening member.

[0007] According to the electrical device disclosed herein, the cooling member is in contact with both the first bus bar and the fastening member. Therefore, the cooling performance can be improved as compared with a structure in which either one is in contact and the other is not in contact.

[0008] Note that the reference numbers in the parentheses above only show an example of the correspondence with the specific configuration in the embodiments described later, and do not limit the technical scope in any way.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

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Figure 8

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Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Embodiments for Carrying Out the Invention

[0010] Hereinafter, a plurality of embodiments will be described with reference to the drawings. In each embodiment, corresponding components may be denoted by the same reference numerals, and redundant descriptions may be omitted. When only a part of the configuration is described in each embodiment, for the other parts of the configuration, the configurations of other embodiments described previously can be applied. Also, not only the combinations of configurations explicitly shown in the description of each embodiment, but also the configurations of a plurality of embodiments can be partially combined with each other without particular problem in the combination.

[0011] The electric device of the present embodiment is, for example, a power conversion device applied to a moving body having a rotating electric machine as a drive source. The moving body is, for example, an electric vehicle (BEV), a hybrid vehicle (HEV), a plug-in hybrid vehicle (PHEV), or other electric vehicles, an electric aircraft such as a drone or an electric vertical take-off and landing aircraft (eVTOL), a ship, a construction machine, or an agricultural machine. Hereinafter, an example applied to a vehicle will be described.

[0012] (First Embodiment) First, based on FIG. 1, the schematic configuration of the drive system of the vehicle will be described.

[0013] <Drive System of Vehicle> As shown in FIG. 1, the drive system 1 of the vehicle includes a DC power supply 2, a motor generator 3, and a power conversion device 4.

[0014] The DC power supply 2 is a DC voltage source composed of a rechargeable secondary battery. The motor generator 3 is a three-phase AC rotating electric machine. The motor generator 3 functions as a driving source for the vehicle to travel, that is, as an electric motor. The motor generator 3 functions as a generator during regeneration. The power conversion device 4 performs power conversion between the DC power supply 2 and the motor generator 3.

[0015] <Circuit Configuration of Power Conversion Device> FIG. 1 shows the circuit configuration of the power conversion device 4. The power conversion device 4 includes at least a power conversion circuit. The power conversion circuit of the present embodiment is an inverter 5. The power conversion device 4 may further include a smoothing capacitor 6, a drive circuit 7, and the like.

[0016] The smoothing capacitor 6 mainly smoothes the DC voltage supplied from the DC power supply 2. The smoothing capacitor 6 is connected to a P line 8 which is a high-potential side power supply line and an N line 9 which is a low-potential side power supply line. The P line 8 is connected to the positive electrode of the DC power supply 2, and the N line 9 is connected to the negative electrode of the DC power supply 2. The positive electrode of the smoothing capacitor 6 is connected to the P line 8 between the DC power supply 2 and the inverter 5. The negative electrode of the smoothing capacitor 6 is connected to the N line 9 between the DC power supply 2 and the inverter 5. The smoothing capacitor 6 is connected in parallel with the DC power supply 2.

[0017] The inverter 5 is a DC-AC conversion circuit. The inverter 5 converts the DC voltage into a three-phase AC voltage according to the switching control by a control circuit (not shown) and outputs it to the motor generator 3. Thereby, the motor generator 3 is driven to generate a predetermined torque. During the regenerative braking of the vehicle, the inverter 5 receives the rotational force from the wheels and converts the three-phase AC voltage generated by the motor generator 3 into a DC voltage according to the switching control by the control circuit and outputs it to the P line 8. In this way, the inverter 5 performs bidirectional power conversion between the DC power supply 2 and the motor generator 3.

[0018] The inverter 5 is configured to include three-phase upper and lower arm circuits 10. The upper and lower arm circuits 10 are sometimes referred to as legs. The upper and lower arm circuits 10 each have an upper arm 10H and a lower arm 10L. The upper arm 10H and the lower arm 10L are serially connected between the P line 8 and the N line 9 with the upper arm 10H on the P line 8 side.

[0019] The connection point between the upper arm 10H and the lower arm 10L, that is, the midpoint of the upper and lower arm circuit 10, is connected to the winding 3a of the corresponding phase in the motor generator 3 via the output line 11. Among the upper and lower arm circuits 10, the U-phase upper and lower arm circuit 10U is connected to the U-phase winding 3a via the output line 11. The V-phase upper and lower arm circuit 10V is connected to the V-phase winding 3a via the output line 11. The W-phase upper and lower arm circuit 10W is connected to the W-phase winding 3a via the output line 11.

[0020] The upper and lower arm circuits 10 (10U, 10V, 10W) have a series circuit 12. The number of series circuits 12 in the upper and lower arm circuits 10 may be one or more. In the case of multiple, the series circuits 12 are connected in parallel with each other to form the upper and lower arm circuit 10 for one phase. The series circuit 12 is configured by serially connecting a switching element on the upper arm 10H side and a switching element on the lower arm 10L side between the P line 8 and the N line 9.

[0021] The number of the switching elements on the high side and the low side that make up the series circuit 12 is not particularly limited. It may be one or more. The series circuit 12 of the present embodiment has two switching elements on the high side and two switching elements on the low side. The two switching elements on the high side are connected in parallel, and the two switching elements on the low side are connected in parallel to form one series circuit 12. That is, each of the six arms 10H, 10L of the upper and lower arm circuits 10 for three phases is composed of two switching elements connected in parallel with each other.

[0022] In this embodiment, an n-channel MOSFET 13 is adopted as each switching element. MOSFET is the abbreviation of Metal Oxide Semiconductor Field Effect Transistor. The two MOSFETs 13 on the high side connected in parallel are turned on and off at the same timing with each other by a common gate drive signal (drive voltage). The two MOSFETs 13 on the low side connected in parallel are turned on and off at the same timing with each other by a common gate drive signal (drive voltage).

[0023] A freewheeling diode 14 (hereinafter referred to as FWD 14) is connected in anti-parallel to each of the MOSFETs 13. In the case of the MOSFET 13, the FWD 14 may be a parasitic diode (body diode) or an external diode. In the upper arm 10H, the drain of the MOSFET 13 is connected to the P line 8. In the lower arm 10L, the source of the MOSFET 13 is connected to the N line 9. And the drain of the MOSFET 13 in the upper arm 10H and the drain of the MOSFET 13 in the lower arm 10L are connected to each other. The anode of the FWD 14 is connected to the source of the corresponding MOSFET 13, and the cathode is connected to the drain.

[0024] Note that the switching element is not limited to the MOSFET 13. For example, an IGBT may be adopted. IGBT is the abbreviation of Insulated Gate Bipolar Transistor. Also in the case of the IGBT, the FWD 14 is connected in anti-parallel.

[0025] The drive circuit 7 drives the switching elements that constitute a power conversion circuit such as the inverter 5. The drive circuit 7 supplies a drive voltage to the gate of the corresponding MOSFET 13 based on the drive command of the control circuit. The drive circuit drives the corresponding MOSFET 13, that is, turns it on and off, by applying the drive voltage. The drive circuit may be referred to as a driver.

[0026] The power conversion device 4 may include a control circuit for the switching element. The control circuit generates a drive command for operating the MOSFET 13 and outputs it to the drive circuit 7. The control circuit generates a drive command based on, for example, a torque request input from a higher-level ECU (not shown) and signals detected by various sensors. ECU is an abbreviation for Electronic Control Unit. The control circuit may be provided within the higher-level ECU.

[0027] <Structure of the power conversion device> FIG. 2 is a plan view showing the power conversion device 4 of the present embodiment. In FIG. 2, the circuit board is omitted so that the arrangement of the semiconductor module and the cooler can be understood. The white arrow in FIG. 2 indicates the direction in which the refrigerant flows. FIG. 3 is a cross-sectional view taken along line III-III of FIG. 2. In FIG. 3, for the sake of convenience, only the semiconductor element and the encapsulation body are shown as the main body part. Also, the part of the external connection terminal encapsulated in the encapsulation body is omitted.

[0028] The power conversion device 4 of the present embodiment includes a base 20 having a first cooler 21, a semiconductor module 30, and a second cooler 40. The power conversion device 4 may include a capacitor 50. The power conversion device 4 may include a circuit board 60. As an example, the power conversion device 4 of the present embodiment includes a base 20 having a first cooler 21, a plurality of semiconductor modules 30, a second cooler 40, a capacitor 50, and a circuit board 60.

[0029] Hereinafter, the arrangement direction of the plurality of semiconductor modules 30 is defined as the X direction. A direction orthogonal to the X direction and in which the first cooler 21, the semiconductor module 30, and the second cooler 40 are stacked is defined as the Z direction. A direction orthogonal to both the X direction and the Z direction is defined as the Y direction. The Y direction corresponds to one direction orthogonal to the stacking direction. The X direction, the Y direction, and the Z direction are in a mutually orthogonal positional relationship. A plan view from the Z direction may simply be referred to as a plan view. When explaining the relative positions of two members, the position of the member closer to the base 20 in the Z direction may be shown as downward, and the position of the member farther from the base 20 may be shown as upward. First, the schematic configuration of each element will be described.

[0030] <Base and the first cooler> The base 20 mounts the semiconductor module 30 on one surface 20a thereof. The base 20 is a support member that supports the semiconductor module 30. In this embodiment as an example, the semiconductor module 30 and the capacitor 50 are arranged on one surface of the base 20. The base 20 is formed using a metal material such as aluminum.

[0031] The base 20 has a first cooler 21. The first cooler 21 is configured using the base 20. The first cooler 21 is a cooling part in the base 20. The first cooler 21 may include a flow path through which a refrigerant flows, or may be a heat dissipation member including a heat sink or heat dissipation fins. As an example, the first cooler 21 of this embodiment is configured to include a flow path 211 formed inside the base 20 and a peripheral portion of the flow path 211 in the base 20, as shown in FIGS. 2 and 3. The refrigerant 212 flows through the flow path 211. As the refrigerant 212, for example, a refrigerant that undergoes a phase change such as water or ammonia, or a refrigerant that does not undergo a phase change such as an ethylene glycol system can be used. The first cooler 21 cools the semiconductor module 30 from the back surface 31b side.

[0032] The base 20 may be provided alone, or may be provided as a part of a case that houses other elements of the power conversion device 4. As an example, the base 20 of this embodiment is provided as the bottom wall of the case 22. The case 22 has an opening for housing other elements. The case 22 has a base 20 forming the bottom wall and side walls 23 that are continuous with the base 20 and define a housing space 22S together with the base 20. As an example, the case 22 of this embodiment has a box shape with one surface open. The case 22 has a substantially rectangular shape in a plan view in the Z direction. In the housing space 22S of the case 22, the semiconductor module 30, the second cooler 40, the capacitor 50, the circuit board 60, etc. are arranged.

[0033] On the side wall 23, an introduction pipe 24 for supplying refrigerant to the first cooler 21 and the second cooler 40 and a discharge pipe 25 for discharging refrigerant from the first cooler 21 and the second cooler 40 are attached. The introduction pipe 24 and the discharge pipe 25 are attached to, for example, the common side wall 23.

[0034] The power conversion device 4 may include a cover (lid), not shown, that closes the opening of the case 22. The case 22 and the cover may be referred to as a housing.

[0035] <Semiconductor module> The semiconductor module 30 constitutes the above-described upper and lower arm circuits 10, that is, the inverter 5. The power conversion device 4 of the present embodiment includes three semiconductor modules 30. One semiconductor module 30 provides one series circuit 12, that is, the upper and lower arm circuit 10 for one phase. The plurality of semiconductor modules 30 includes a semiconductor module 30U that constitutes the upper and lower arm circuit 10U, a semiconductor module 30V that constitutes the upper and lower arm circuit 10V, and a semiconductor module 30W that constitutes the upper and lower arm circuit 10W. As shown in FIG. 2, the three semiconductor modules 30 are arranged side by side in the X direction.

[0036] All the semiconductor modules 30 have a common structure with each other. Each semiconductor module 30 includes a main body portion 31 and external connection terminals 32 protruding from the main body portion 31. The main body portion 31 includes a semiconductor element 33, a sealing body 34, and the like.

[0037] As an example, the semiconductor element 33 of the present embodiment is formed by forming the above-described n-channel type MOSFET 13 and FWD 14 on a semiconductor substrate made of SiC. The MOSFET 13 has a vertical structure such that the main current flows in the thickness direction of the semiconductor element 33 (semiconductor substrate). The semiconductor element 33 has main electrodes on both surfaces in its own thickness direction. Specifically, each of the semiconductor elements 33 has a drain electrode on one surface and a source electrode on the back surface.

[0038] The main current flows between the drain electrode and the source electrode. The semiconductor element 33 of the present embodiment includes two semiconductor elements 33H that provide the switching element on the high side of the series circuit 12 and two semiconductor elements 33L that provide the switching element on the low side of the series circuit 12. The semiconductor elements 33H and 33L are arranged side by side in the Y direction. The two semiconductor elements 33H are arranged side by side in the X direction. Similarly, the two semiconductor elements 33L are arranged side by side in the X direction.

[0039] The sealing body 34 seals a part of each of the semiconductor element 33 and the external connection terminal 32. The other part of each of the external connection terminals 32 protrudes outside the sealing body 34. The sealing body 34 is made of a resin such as an epoxy resin. The sealing body 34 has a substantially rectangular planar shape, for example. The sealing body 34 forms the outer contour of the main body 31.

[0040] The sealing body 34, that is, the main body 31, has a front surface 31a as the surface forming the outer contour and a back surface 31b that is the surface opposite to the front surface 31a in the Z direction. The front surface 31a and the back surface 31b are flat surfaces, for example. It also has side surfaces 31c and 31d that connect the front surface 31a and the back surface 31b. The side surface 31c is the surface opposite to the side surface 31d in the Y direction.

[0041] The plurality of external connection terminals 32 includes main terminals 32P, 32N, 32O electrically connected to the main electrodes of the semiconductor element 33 and signal terminals 32S. The main terminal 32P is electrically connected to the drain electrode of the semiconductor element 33H. The main terminal 32N is electrically connected to the source electrode of the semiconductor element 33L. The main terminal 32P may be referred to as a P terminal, a high-potential power supply terminal, a positive electrode terminal, etc. The main terminal 32N may be referred to as an N terminal, a low-potential power supply terminal, a negative electrode terminal, etc. The main terminals 32P and 32N are electrically connected to the capacitor 50, that is, the smoothing capacitor 6. The main terminals 32P and 32N protrude outside from the side surface 31c of the main body 31. The protruding portions of the main terminals 32P and 32N are arranged side by side in the X direction. Note that the signal terminal 32S also protrudes from the side surface 31c of the main body 31.

[0042] The main terminal 32O is electrically connected to the connection point between the source electrode of the semiconductor element 33H and the drain electrode of the semiconductor element 33L, that is, the connection point (midpoint) of the series circuit 12. The main terminal 32O protrudes outward from the side surface 31d of the main body 31. The main terminal 32O may be referred to as an O terminal, an output terminal, an AC terminal, etc. The main terminal 32O is connected to the corresponding winding 3a of the motor generator 3 via a bus bar (not shown), for example.

[0043] The semiconductor module 30 described above is disposed on the first cooler 21 such that one surface 31a of the main body 31, that is, the surface on which the drain electrode 33D of the semiconductor element 33 is formed, faces one surface 20a of the base 20. A heat conductive member may be disposed between the semiconductor module 30 and the first cooler 21. As an example, in the present embodiment, the heat conductive member 70 is interposed between the semiconductor module 30 and the first cooler 21. The heat conductive member 70 transfers the heat of the semiconductor module 30, for example, the heat generated by the semiconductor element 33, to the first cooler 21. The heat conductive member 70 has electrical insulation. As an example, the heat conductive member 70 of the present embodiment is heat conductive grease. Instead of the heat conductive grease, a heat conductive gel may be used.

[0044] <Second Cooler> The second cooler 40 is provided without diverting the base 20 (case 22). The second cooler 40 is disposed on the back surface 31b of the semiconductor module 30. The second cooler 40 is laminated and disposed on the main body 31 of the semiconductor module 30 on the opposite side of the first cooler 21 so as to face the surface on which the source electrode of the semiconductor element 33 is formed. The heat conductive member 70 described above may be disposed between the second cooler 40 and the semiconductor module 30. The second cooler 40 cools the semiconductor module 30 from the opposite side of the first cooler 21 in the Z direction. The second cooler 40 and the first cooler 21 can cool the semiconductor module 30 from both sides in the Z direction.

[0045] The second cooler 40 has a flow path 41 inside thereof. Refrigerant 42 is supplied to the flow path 41 via an introduction pipe 24. The refrigerant 42 that has flowed through the flow path 41 is discharged outside the power conversion device 4 via a discharge pipe 25. The second cooler 40 is disposed in the accommodation space 22S of the case 22. The refrigerant 42 is common to the above-described refrigerant 212. The second cooler 40 is connected to the first cooler 21 via connection pipes 45 and 46.

[0046] A part of the refrigerant supplied from the introduction pipe 24 flows through the flow path 211 as the refrigerant 212 and is discharged from the discharge pipe 25. The other part of the refrigerant is supplied to the flow path 41 through the flow paths of the flow path 211 and the connection pipe 45. The refrigerant 42 that has flowed through the flow path 41 flows into the flow path 211 through the flow path of the connection pipe 46 and is discharged from the discharge pipe 25.

[0047] <Capacitor> The capacitor 50 provides the smoothing capacitor 6 described above. The capacitor 50 includes, for example, a case (not shown) and capacitor elements housed in the case. In FIGS. 2 and 3, the capacitor 50 is illustrated in a simplified manner.

[0048] As an example, the capacitor element of the present embodiment is a film capacitor element. The capacitor element is formed by winding a film around an axis in the Z direction, for example. The capacitor element has electrodes (not shown) on both end faces in the Z direction. The capacitor 50 includes a P terminal 51P connected to the electrode on the positive electrode side and an N terminal 51N connected to the electrode on the negative electrode side.

[0049] The P terminal 51P and the N terminal 51N are plate-shaped metal members. The P terminal 51P and the N terminal 51N are connected to the corresponding electrodes by soldering, resistance welding, laser welding, or the like. The P terminal 51P and the N terminal 51N may be referred to as a capacitor bus bar or the like. In FIGS. 2 and 3, the connection portions of the P terminal 51P and the N terminal 51N with the corresponding main terminals 32P and 32N are illustrated. The P terminal 51P and the N terminal 51N have connection portions (not shown) for electrically connecting the smoothing capacitor 6 and the DC power supply 2.

[0050] The capacitor 50 is disposed on one surface 20a of the base 20 that constitutes the first cooler 21. The capacitor 50 of the present embodiment is disposed in the accommodation space 22S of the case 22. The capacitor 50 is arranged side by side with the semiconductor module 30 in the Y direction. The capacitor 50 has a substantially rectangular planar shape with the X direction as the longitudinal direction in plan view.

[0051] The connection portions of the P terminal 51P and the N terminal 51N are drawn out toward the semiconductor module 30 side in the Y direction. The connection portions of the P terminal 51P and the N terminal 51N are arranged such that the plate surfaces face each other in order to reduce the inductance. The connection portions of the P terminal 51P and the N terminal 51N have different extension lengths in the Y direction so as to be connectable to the P bus bar 52P and the N bus bar 52N. As an example, in the present embodiment, the connection portion of the N terminal 51N is located below the connection portion of the P terminal 51P. And the connection portion of the N terminal 51N is longer than the connection portion of the P terminal 51P in the Y direction.

[0052] The capacitor 50 further includes a P bus bar 52P and an N bus bar 52N. The P bus bar 52P and the N bus bar 52N are plate-shaped metal members. The P bus bar 52P and the N bus bar 52N may be held in a predetermined positional relationship by, for example, an insulating member (not shown). The P bus bar 52P and the N bus bar 52N are arranged such that the plate surfaces face each other in most of the entire length in order to reduce the inductance. The P bus bar 52P electrically connects the main terminal 32P of the semiconductor module 30 and the P terminal 51P of the capacitor 50. The N bus bar 52N electrically connects the main terminal 32N of the semiconductor module 30 and the N terminal 51N of the capacitor 50.

[0053] As shown in FIG. 4, the P bus bar 52P of the present embodiment has a base portion 521P extending in the Z direction and extending portions 522P and 523P extending in the Y direction from both ends of the base portion 521P. The extending portion 522P extends in the Y direction from the lower end of the base portion 521P toward the semiconductor module 30. The extending portion 522P is connected to the main terminal 32P. The extending portion 523P extends in the Y direction from the upper end of the base portion 521P toward the capacitor 50. The extending portion 523P is connected to the P terminal 51P.

[0054] Similarly, the N bus bar 52N has a base portion 521N extending in the Z direction and extending portions 522N and 523N extending in the Y direction from both ends of the base portion 521N. The extending portion 522N extends in the Y direction from the lower end of the base portion 521N toward the semiconductor module 30. The extending portion 522N is connected to the main terminal 32N. The extending portion 523N extends in the Y direction from the upper end of the base portion 521N toward the capacitor 50. The extending portion 523N is connected to the N terminal 51N.

[0055] The P bus bar 52P and the N bus bar 52N can be connected to the corresponding main terminals 32P, 32N and terminals 51P, 51N by soldering, resistance welding, laser welding, etc. As an example, the P bus bar 52P and the N bus bar 52N of the present embodiment are connected to the corresponding P terminal 51P and N terminal 51N by laser welding.

[0056] <Circuit board> Although not shown in the figure, the circuit board 60 includes a wiring board in which wirings are arranged on an insulating base material such as resin, electronic components mounted on the wiring board, connectors, etc. A circuit is configured by the mounted electronic components and the wirings. The drive circuit 7 described above is configured on the circuit board 60.

[0057] The circuit board 60 is arranged so as to overlap with the semiconductor module 30 in a plan view in the Z direction. The circuit board 60 is arranged above the three semiconductor modules 30. The signal terminals 32S of the three semiconductor modules 30 are mounted on the circuit board 60. As an example, the circuit board 60 of the present embodiment is arranged in the accommodation space 22S of the case 22. The circuit board 60 is located above the second cooler 40.

[0058] <Bus bar connection structure> As shown in FIGS. 4 and 5, the P bus bar 52P and the N bus bar 52N (second bus bar) and the main terminals 32P, 32N (first bus bar) are fastened to each other by a fastening member 80. Thereby, the P bus bar 52P and the main terminal 32P form an energization path of the P line 8, and the N bus bar 52N and the main terminal 32N form an energization path of the N line 9.

[0059] The fastening member 80 is configured to include a bolt 81 and a nut 82. The bolt 81 and the nut 82 are made of metal. Through holes 32a are formed in the main terminals 32P, 32N, and through holes 52a are formed in the P bus bar 52P and the N bus bar 52N. The bolt 81 is inserted into the mutual through holes 32a, 52a. By tightening the bolt 81 inserted in this way with the nut 82 in the Z direction, the P bus bar 52P and the main terminal 32P are fastened to each other, and the N bus bar 52N and the main terminal 32N are also fastened to each other.

[0060] In the example shown in FIG. 5, the main terminals 32P, 32N are arranged below the P bus bar 52P and the N bus bar 52N. The bolt 81 is inserted from the side of the main terminals 32P, 32N. That is, the head 812 of the bolt 81 is in close contact with the main terminals 32P, 32N, and the nut 82 is in close contact with the P bus bar 52P and the N bus bar 52N.

[0061] Next, the detailed structure of the bolt 81 will be described with reference to FIGS. 6 and 7. The bolt 81 has a shaft portion 811, a head portion 812, a diameter-expanded portion 813, and a clamping portion 814. The shaft portion 811 is a portion that extends in the Z direction and is inserted into the through holes 32a and 52a, and has a thread formed thereon for screwing with the nut 82. The head portion 812 provides a seating surface that is pressed against and adheres to the bus bar bottom surface 32b, which is one surface of the main terminals 32P and 32N.

[0062] The diameter-expanded portion 813 is formed between the head portion 812 and the shaft portion 811, and has a disk shape with a diameter larger than that of the shaft portion 811. However, the diameter of the diameter-expanded portion 813 is smaller than that of the head portion 812. The clamping portion 814 has a shape that protrudes radially from the outer peripheral surface of the diameter-expanded portion 813, and a plurality of the clamping portions 814 are arranged at equal intervals in the circumferential direction of the diameter-expanded portion 813.

[0063] As shown in FIG. 7, in a state where the bolt 81 is being inserted into the through hole 32a, that is, a state where the seating surface of the head portion 812 has not reached the bus bar bottom surface 32b, the clamping portion 814 is not deformed. When the bolt 81 is pushed into the through hole 32a from the state shown in FIG. 7 to the state shown in FIG. 8, the clamping portion 814 is crushed radially between the inner wall surface of the through hole 32a. That is, the clamping portion 814 is plastically deformed in the radial direction of the through hole 32a and clamped to the main terminal 32P. As a result, the bolt 81 is positioned so as not to be movable radially with respect to the main terminal 32P.

[0064] In the present embodiment, even in the state of FIG. 8 where the clamping is completed, the bolt bottom surface 812a, which is one surface of the head portion 812, is located below the bus bar bottom surface 32b, and the vertical positions of the bolt bottom surface 812a and the bus bar bottom surface 32b do not coincide. That is, a part of the bolt side surface 812b, which is the side surface of the head portion 812, protrudes downward from the bus bar bottom surface 32b. In this way, a step is formed at the boundary between the main terminal 32P and the fastening member 80 due to the protrusion of the bolt side surface 812b.

[0065] <Bus bar cooling structure> The main terminals 32P, 32N (first bus bar), P bus bar 52P (second bus bar), and N bus bar 52N (second bus bar) generate heat when energized. A cooling member 90 for cooling the heat is provided. The cooling member 90 has a contact portion 91, an electrical insulation portion 92, and a cooling portion 93.

[0066] The cooling portion 93 is a part of the base 20 that supports the semiconductor module 30. The cooling portion 93 has a shape that protrudes upward from a portion of the one surface 20a where the heat conduction member 70 is disposed. The cooling portion 93 is cooled by the refrigerant 212 and has a lower temperature than the ambient temperature of the main terminals 32P, 32N. That is, it can be said that the cooling portion 93 is also a part of the first cooler 21.

[0067] The cooling surface 93a, which is one surface of the cooling portion 93, is provided so as to overlap at least a part of these bus bars in plan view so as to effectively cool the main terminals 32P, 32N, P bus bar 52P, and N bus bar 52N. In the example shown in FIGS. 3 to 5, the cooling surface 93a is provided so as to enclose all the fastening members 80 in plan view. The cooling surface 93a extends along the arrangement direction of the plurality (six) of fastening members 80 in plan view, that is, the X direction.

[0068] The flow path 211 of the first cooler 21 is provided so as to overlap at least a part of the cooling surface 93a in plan view (see FIG. 3). Further, the flow path 211 is provided so as to overlap at least a part of these bus bars in plan view so as to effectively cool the main terminals 32P, 32N, P bus bar 52P, and N bus bar 52N. Further, the flow path 211 is provided so as to overlap at least a part of the fastening members 80 in plan view. Further, the flow path 211 extends along the arrangement direction of the plurality of fastening members 80 in plan view, that is, the X direction.

[0069] The electrical insulation part 92 is disposed between the main terminals 32P and 32N and the cooling part 93. The electrical insulation part 92 is a member such as a resin having electrical insulation properties. The electrical insulation part 92 is in a sheet shape and has the same shape as the cooling surface 93a in plan view, that is, a rectangle with the X direction as the longitudinal direction. The electrical insulation part 92 has a main body sheet part 92a and an extension part 92b. The main body sheet part 92a has a shape that covers the entire cooling surface 93a. The extension part 92b has a shape that extends downward from the outer edge of the main body sheet part 92a and extends annularly in plan view.

[0070] The close contact part 91 is disposed between the main terminals 32P and 32N and the electrical insulation part 92. In short, on the cooling surface 93a of the cooling part 93, the electrical insulation part 92, the close contact part 91, and the main terminals 32P and 32N are laminated and arranged in this order. The lower surface of the electrical insulation part 92 is in contact with the cooling surface 93a, and the upper surface of the electrical insulation part 92 is in contact with the close contact part 91. The upper surface of the close contact part 91 is in contact with the main terminals 32P and 32N, and this contact state will be described in detail later.

[0071] The heat generated in the main terminals 32P and 32N, the P bus bar 52P, and the N bus bar 52N during energization moves to the cooling part 93 through the close contact part 91 and the electrical insulation part 92. That is, the main terminals 32P and 32N, the P bus bar 52P, and the N bus bar 52N are cooled by the cooling member 90. Further, the cooling member 90 is in contact with the main terminals 32P and 32N and is also in contact with the fastening member 80. Therefore, the heat generated in the bus bar is also cooled by the cooling member 90 through the heat transfer path via the fastening member 80.

[0072] A material having higher thermal conductivity than the electrical insulation part 92 is used for the close contact part 91. A material having higher electrical insulation properties than the close contact part 91 is used for the electrical insulation part 92. Also, a softer material than the electrical insulation part 92 is used for the close contact part 91. For example, the same thermal conductive grease or thermal conductive gel as the thermal conductive member 70 is used for the close contact part 91. The dimension (thickness) of the close contact part 91 in the Z direction is larger than the thickness of the sheet-shaped electrical insulation part 92.

[0073] The contact surface 91a, which is one surface of the contact portion 91, is in contact with the bus bar bottom surface 32b of the main terminals 32P and 32N. Further, the contact surface 91a is also in contact with the bolt 81. Specifically, the contact portion 91 is in contact with the bolt bottom surface 812a and the bolt side surface 812b of the head portion 812. In short, the contact portion 91 is in contact with the main terminals 32P and 32N and the fastening member 80 in a state of being deformed following the boundary step between the main terminals 32P and 32N and the fastening member 80.

[0074] <Y - Condenser Function> As described above, the cooling portion 93 is a part of the base 20, and the base 20 is connected to a ground such as a vehicle body and has a ground potential. That is, the cooling portion 93 is also a ground portion having a ground potential. The cooling portion 93 as the ground portion is thermally connected to the first bus bar, the second bus bar, and the fastening member 80 in a state of being electrically insulated by the electrical insulation portion 92. As a result, the function of the Y - capacitor shown by the dashed - dotted line in FIG. 1 is exhibited. That is, substantially, it can be said that the P - side Y - capacitor Y1 is connected between the P - line 8 and the ground, and the N - side Y - capacitor Y2 is connected between the N - line 9 and the ground.

[0075] One electrode of the P - side Y - capacitor Y1 is provided by the P - bus bar 52P and the main terminal 32P, and the other electrode is provided by the cooling portion 93. The insulating layer disposed between these pair of electrodes is provided by the electrical insulation portion 92. One electrode of the N - side Y - capacitor Y2 is provided by the N - bus bar 52N and the main terminal 32N, and the other electrode is provided by the cooling portion 93. The insulating layer disposed between these pair of electrodes is provided by the electrical insulation portion 92 in the same manner as the P - side Y - capacitor Y1. These Y - capacitors are filter capacitors for removing power supply noise from the DC power supply 2 and are also called noise absorption capacitors.

[0076] <Summary of the First Embodiment> As described above, in the present embodiment, the cooling member 90 contacts not only the main terminals 32P and 32N (the first bus bar) but also the fastening member 80, and contacts both the first bus bar and the fastening member 80. Therefore, a heat transfer path via the fastening member 80 is added to the heat transfer path from the first bus bar to the cooling member 90. Thus, the cooling performance of the cooling member 90 with respect to the first bus bar can be improved.

[0077] Furthermore, in the present embodiment, the fastening member 80 includes a caulking portion 814 that plastically deforms in the radial direction of the through holes 32a of the main terminals 32P and 32N and is caulked to the main terminals 32P and 32N (the first bus bar). Here, if the fastening member 80 does not contact the cooling member 90 contrary to the present embodiment, the difference between the thermal contraction amount of the first bus bar and the thermal contraction amount of the fastening member 80 becomes large, and there is a possibility that the caulking may become loose. On the other hand, in the present embodiment, since the fastening member 80 contacts the cooling member 90, the difference in the thermal contraction amount described above can be reduced, and the possibility of the caulking becoming loose can be reduced. That is, when the fastening member 80 has the caulking portion 814, in addition to the effect of improving the cooling performance, the effect of preventing the caulking from loosening is also exhibited.

[0078] Furthermore, in the present embodiment, the cooling member 90 contacts the head portion 812 of the bolt. According to this, compared with the case where the cooling member 90 contacts the nut 82, the thickness of the contact portion 91 can be reduced, and the heat transfer path to the cooling portion 93 can be shortened, so that the cooling performance can be further improved. Also, compared with the case where the cooling member 90 contacts the tip of the shaft portion 811, the contact area between the bolt 81 and the contact portion 91 can be increased, so that the cooling performance can be further improved.

[0079] Furthermore, in the present embodiment, the current-carrying path formed by the main terminals 32P and 32N (the first bus bar) and the P bus bar 52P and the N bus bar 52N (the second bus bar) is a path for energizing between the upper and lower arm circuits 10 and the smoothing capacitor 6. And the cooling portion 93 functions as a ground portion having a ground potential, and is thermally connected to the first bus bar and the fastening member 80 while being electrically insulated from the first bus bar and the fastening member 80. According to this, the cooling member 90, the fastening member 80, and the bus bar can exhibit the function of a Y capacitor.

[0080] Furthermore, in the present embodiment, the cooling member 90 includes a close contact portion 91 that closely contacts the first bus bar and the fastening member 80 in a state deformed following the boundary step between the main terminals 32P and 32N (the first bus bar) and the fastening member 80. Therefore, the thermal resistance between the boundary step and the cooling member 90 can be reduced, and the cooling performance of the cooling member 90 with respect to the first bus bar can be further improved.

[0081] Furthermore, in the present embodiment, the cooling portion 93 is thermally connected to the main terminals 32P and 32N (the first bus bar) and the fastening member 80 via the electrical insulation portion 92 and the close contact portion 91. According to this, since the electrical insulation portion 92 and the close contact portion 91 are separate members, even if a crack occurs in the close contact portion 91 due to thermal shrinkage, vibration, or the like, the electrical insulation portion 92 may not be damaged and insulation can be ensured. That is, the reliability with respect to electrical insulation can be improved.

[0082] (Second Embodiment) In the first embodiment described above, the electrical insulation portion 92 has the extending portion 92b. In contrast, in the present embodiment, as shown in FIG. 9, the electrical insulation portion 92 has two extending portions 92b and 92c. The extending portion 92b corresponds to the first extending portion, and the extending portion 92c corresponds to the second extending portion.

[0083] The extending portion 92b has the same structure as that in the first embodiment and extends along the side surface 93b of the cooling portion 93. The extending portion 92c added in the present embodiment extends along the side surface 91b of the close contact portion 91. More specifically, the extending portion 92c has a shape that extends upward from the outer edge of the main body sheet portion 92a and extends annularly in a plan view.

[0084] As described above, in the present embodiment, since the side surface 93b of the cooling unit 93 is covered by the extending unit 92b (first extending unit), the creepage distance between the first bus bar or the second bus bar and the cooling unit 93 can be increased. Therefore, the reliability of the electrical insulation between the bus bar and the cooling unit 93 can be improved. Moreover, since the creepage distance can be increased as described above, even if the thicknesses of the adhesion unit 91 and the electrical insulation unit 92 are reduced, electrical insulation can be ensured. Therefore, by reducing the above thickness, the distance of the heat transfer path from the cooling unit 93 to the bus bar can be shortened, and the cooling performance can be improved.

[0085] Furthermore, in the present embodiment, since the side surface 91b of the adhesion unit 91 is covered by the extending unit 92c (second extending unit), the creepage distance between the adhesion unit 91 and the cooling unit 93 can be increased. Therefore, the reliability of the electrical insulation between the adhesion unit 91 and the cooling unit 93 can be improved. Moreover, by providing the extending unit 92c, it is possible to prevent the adhesion unit 91 from shifting in the direction orthogonal to the Z direction. Therefore, it is possible to suppress the adhesion unit 91 from coming out from between the electrical insulation unit 92 and the bus bar due to vibration or the like.

[0086] (Third Embodiment) In the present embodiment, the adhesion unit 91 according to the first embodiment is used as the first adhesion unit, and in addition to this first adhesion unit, a second adhesion unit 910 is provided. As shown in FIG. 10, the second adhesion unit 910 is disposed between the electrical insulation unit 92 and the cooling unit 93 and is in close contact with the cooling surface 93a. The electrical insulation unit 92 is disposed between the first adhesion unit and the second adhesion unit 910.

[0087] According to the present embodiment, even when the flatness accuracy of the cooling surface 93a is poor, since the second adhesion unit 910 is in close contact and transfers heat, the thermal resistance can be reduced. Therefore, the cooling performance of the cooling member 90 with respect to the bus bar can be further improved.

[0088] (Fourth Embodiment) In each of the above embodiments, the bolt 81 is in contact with the cooling member 90. In contrast, in the present embodiment, as shown in FIG. 11, the nut 82 is in contact with the cooling member 90. Specifically, the head 812 fastens both busbars from the side of the P busbar 52P instead of the main terminal 32P. The nut 82 fastens both busbars from the side of the main terminal 32P instead of the P busbar 52P. The nut 82 is in close contact with the close contact portion 91. The close contact portion 91 deforms following the boundary step between the main terminals 32P and 32N (the first busbar) and the nut 82. Further, the close contact portion 91 deforms following the boundary step between the tip of the shaft portion 811 and the nut 82. As a result, the close contact portion 91 also comes into contact with the bolt 81 in addition to the nut 82. As described above, the present embodiment exhibits the same effects as those of the first embodiment.

[0089] (Fifth Embodiment) In each of the above embodiments, the fastening member 80 in contact with the cooling member 90 fastens two busbars. The two busbars are the first busbar and the second busbar. In contrast, in the present embodiment, as shown in FIG. 12, the fastening member 80 fastens three busbars. The three busbars are the first busbar, the second busbar, and the third busbar. The current-carrying path formed by these three busbars branches from the fastening portion by the fastening member 80 into an inverter path, a capacitor path, and a battery path.

[0090] The inverter path is a current-carrying path that branches from the fastening portion by the fastening member 80 to the MOSFET 13 (semiconductor) and is provided by the main terminals 32P and 32N. The capacitor path is a current-carrying path that branches from the fastening portion by the fastening member 80 to the smoothing capacitor 6 and is provided by the P busbar 52P and the N busbar 52N. The battery path is a current-carrying path that branches from the fastening portion by the fastening member 80 to the DC power supply 2 (battery) and is provided by the power busbar 53.

[0091] One of the pair of power busbars 53 is connected to the main terminal 32P and the P busbar 52P, and is also connected to the high potential side of the DC power supply 2. The other of the pair of power busbars 53 is connected to the main terminal 32N and the N busbar 52N, and is also connected to the low potential side of the DC power supply 2.

[0092] A through hole 53a is formed in the power busbar 53. A bolt 81 is inserted into the through hole 53a. By fastening a nut 82 to the bolt 81, the power busbar 53 on the high potential side is fastened to the P busbar 52P and the main terminal 32P, and the power busbar 53 on the low potential side is fastened to the N busbar 52N and the main terminal 32N.

[0093] These three busbars are stacked and arranged in the Z direction. In the example shown in FIG. 12, the power busbar 53 contacts the head 812. The P busbar 52P and the N busbar 52N contact the nut 82. That is, the main terminals 32P and 32N are arranged between the P busbar 52P and the N busbar 52N and the power busbar 53 and are clamped. The power busbar 53 contacts the cooling member 90 and corresponds to the first busbar. The P busbar 52P and the N busbar 52N correspond to the second busbar, and the main terminals 32P and 32N correspond to the third busbar.

[0094] Note that the configurations of the contact portion 91 and the electrical insulation portion 92 are the same as those in the above embodiments in this embodiment. In this embodiment, the contact surface 91a, which is one surface of the contact portion 91, contacts the busbar bottom surface 53b of the power busbar 53.

[0095] The direction extending from the fastening portion of the third busbar clamped in the middle is opposite to the direction extending from the fastening portions of the first busbar and the second busbar. That is, the direction extending from the fastening portion of the third busbar is the right side of the paper surface in FIG. 12 in the Y direction. In contrast, the directions extending from the fastening portions of the first busbar and the second busbar located on both sides of the third busbar are the left side of the paper surface in FIG. 12 in the Y direction.

[0096] In each of the above-described embodiments where the fastening member 80 fastens two busbars, the battery path branches not from the fastening portion but from the middle of the inverter path or the capacitor path. In this case, the power supply busbar 53 may be integrally formed with other busbars. Alternatively, the power supply busbar 53 may be fastened to the second busbar or the third busbar using a fastening member different from the fastening member 80.

[0097] Here, at the contact surfaces S1 and S2 between the busbars shown in FIG. 12, the electrical resistance is greater than the electrical resistance inside the busbar. Therefore, the amount of heat generated in the busbar due to energization is greater at the contact surfaces S1 and S2 between the busbars. That is, the contact surfaces S1 and S2 are likely to experience a temperature rise. In particular, when three busbars are fastened at one location as in this embodiment, the temperature at the fastening portion is more likely to rise compared to the case where two busbars are fastened.

[0098] In view of this point, in this embodiment, the current-carrying path formed by a plurality of busbars to be fastened includes three paths, namely, the inverter path, the capacitor path, and the battery path. And the busbars forming each path, that is, the first busbar, the second busbar, and the third busbar, are fastened at one location by a common fastening member 80. Moreover, the cooling member 90 is in contact not only with the power supply busbar 53 (the first busbar) but also with the fastening member 80, and is in contact with both the first busbar and the fastening member 80. Therefore, the effect of improving the cooling performance exerted by contacting both is preferably exerted at the fastening portion where the temperature is likely to rise due to the fastening of the three busbars.

[0099] Here, in the inverter path and the capacitor path among the current-carrying paths, an alternating current component mainly flows. On the other hand, in the battery path, a direct current component mainly flows. Therefore, the heat generated in the busbar due to energization is greater in the power supply busbar 53 forming the battery path than in the busbars forming the inverter path and the capacitor path.

[0100] In view of this point, in the present embodiment, the power supply bus bar 53 is formed separately from other bus bars and is connected to other bus bars by fastening members 80. Therefore, compared with the case where the power supply bus bar 53 is integrally formed with other bus bars without fastening, the influence of heat received by other bus bars from the power supply bus bar 53 can be reduced.

[0101] As described above, since a direct current component current mainly flows in the battery path, the temperature tends to rise. That is, among the contact surfaces S1 and S2 between the bus bars, the contact surface S1 related to the power supply bus bar 53 is more likely to have a temperature rise than the other contact surface S2. In view of this point, in the present embodiment, the power supply bus bar 53 forming the battery path is applied to the first bus bar that contacts the cooling member 90. Therefore, the contact surface S1 that is likely to have a temperature rise among the two contact surfaces S1 and S2 is arranged at a position close to the cooling member 90. Thus, when cooling the fastening portion of the three bus bars with the cooling member 90, the cooling efficiency can be improved.

[0102] (Sixth Embodiment) In the above fifth embodiment, the power supply bus bar 53 forming the battery path is applied to the first bus bar that contacts the cooling member 90. In contrast, in the present embodiment, as shown in FIG. 13, the bus bars forming the capacitor path, that is, the P bus bar 52P and the N bus bar 52N, are applied to the first bus bar.

[0103] In the present embodiment, the contact surface 91a, which is one surface of the close contact portion 91, is in close contact with the bus bar bottom surfaces 52b of the P bus bar 52P and the N bus bar 52N. The main terminals 32P and 32N are applied to the third bus bar that is located in the middle of the two bus bars and is sandwiched in the same manner as in the fifth embodiment. The P bus bar 52P and the N bus bar 52N are applied to the second bus bar.

[0104] Here, the smoothing capacitor 6 is also a heat-generating component that generates heat when energized. If the temperature of the smoothing capacitor 6 rises excessively, it will cause performance degradation and deterioration of the smoothing capacitor 6. In view of this point, in the present embodiment, the P bus bar 52P and the N bus bar 52N that form the capacitor path are applied to the first bus bar that contacts the cooling member 90. Therefore, the P bus bar 52P and the N bus bar 52N will be arranged at positions close to the cooling member 90. Thus, when cooling the fastening portions of the three bus bars with the cooling member 90, it is possible to promote the suppression of the temperature rise of the smoothing capacitor 6.

[0105] In addition, in the above-described fifth and sixth embodiments, any bus bar related to the inverter path, the capacitor path, or the battery path can be applied as the first bus bar. Also, any of these three types of bus bars can be applied as the second bus bar. Further, any of these three types of bus bars can be applied as the bus bar sandwiched in the middle of the three bus bars.

[0106] (Seventh Embodiment) In each of the above embodiments, the fastening member 80 is cooled by one cooling member 90. In contrast, in the present embodiment shown in FIG. 14, the fastening member 80 is cooled by two cooling members 90 and 90x. Note that the cooling member 90 described in each of the above embodiments corresponds to the first cooling member, and the cooling member 90x added in the present embodiment corresponds to the second cooling member. Also, the main terminals 32P and 32N correspond to the first bus bar, and the P bus bar 52P and the N bus bar 52N correspond to the second bus bar.

[0107] The cooling member 90x has a close contact portion 91x, a second close contact portion 910x, an electrical insulation portion 92x, and a cooling portion 93x in the same manner as the cooling member 90.

[0108] The cooling section 93x is part of the case 22. In this case, the cooling section 93x is cooled by the refrigerant 212 and can also be said to be part of the first cooler 21. Alternatively, part of the second cooler 40 may be the cooling section 93x. In this case, the cooling section 93x is cooled by the refrigerant 42 and can also be said to be part of the second cooler 40. Alternatively, part of a cover (lid) (not shown) that closes the opening of the case 22 may be the cooling section 93x.

[0109] The cooling surface 93ax, which is one surface of the cooling section 93x, is provided so as to overlap at least a part of these busbars in a plan view so as to effectively cool the first busbar and the second busbar. In the example shown in FIG. 14, the cooling surface 93ax is provided so as to enclose the entire fastening member 80 in a plan view. Further, the cooling surface 93ax and the cooling surface 93a are in a positional relationship of facing each other in the Z direction.

[0110] The electrical insulation part 92x is disposed between the second busbar and the cooling section 93x. The electrical insulation part 92x has the same material and shape as the electrical insulation part 92, and includes a main body sheet part 92ax and extension parts 92bx, 92cx. The main body sheet part 92ax is shaped to cover the entire cooling surface 93ax. The extension part 92bx extends upward from the outer edge of the main body sheet part 92ax and extends in an annular shape in a plan view. The extension part 92cx extends downward from the outer edge of the main body sheet part 92ax and extends in an annular shape in a plan view.

[0111] The close contact part 91x is disposed between the second busbar and the electrical insulation part 92x. The second close contact part 910x is disposed between the electrical insulation part 92x and the cooling surface 93ax. In short, on the cooling surface 93ax, the second close contact part 92x, the electrical insulation part 92x, the close contact part 91x, and the second busbar are laminated and arranged in this order.

[0112] Part of the heat generated in the first bus bar and the second bus bar due to energization moves to the cooling part 93x through the contact part 91x, the electrical insulation part 92x, and the second contact part 92x. That is, the first bus bar and the second bus bar are cooled by the cooling member 90x. Further, the cooling member 90x contacts the second bus bar and also contacts the fastening member 80. Therefore, the heat generated in the bus bar is also cooled by the cooling member 90x through the heat transfer path via the fastening member 80. Note that the cooling effect by the cooling member 90 is the same as in the above-described embodiments. According to the present embodiment, the bus bar and the fastening member 80 are cooled by the two cooling members 90 and 90x.

[0113] The same material as the above-described contact part 91 is used for the contact part 91x and the second contact part 92x. The contact part 91x is in contact with the bus bar upper surface 52c of the second bus bar and also in contact with the nut 82. Further, the contact part 91x is also in contact with the end surface 811a of the shaft part 811 of the bolt 81. In short, the contact part 91x is in contact with the second bus bar and the fastening member 80 in a state of being deformed following the boundary step between the nut 82 and the bolt 81.

[0114] As described above, in the present embodiment, separately from the first cooling member, a cooling member 90x (second cooling member) that cools the heat generated in the first bus bar and the second bus bar due to energization is provided. The second cooling member is in contact with both the second bus bar and the fastening member 80. Thus, in the present embodiment, since the bus bar and the fastening member 80 are cooled by the two cooling members 90 and 90x, the heat dissipation can be improved as compared with the case of cooling with one cooling member.

[0115] Furthermore, in the present embodiment, one of the first cooling member and the second cooling member is in contact with the head 812 of the bolt 81. The other of the first cooling member and the second cooling member is in contact with the nut 82. Therefore, since the fastening member 80 can be cooled from both axial sides of the bolt 81, it is possible to efficiently cool the contact surface between the bus bars via the fastening member 80.

[0116] Note that the above-described fifth or sixth embodiment may be combined with this embodiment. That is, in the structure in which the three bus bars are fastened by the fastening member 80, the first cooling member and the second cooling member may be used to cool the three bus bars from both sides.

[0117] (Other embodiments) As described above, a plurality of embodiments of the present disclosure have been described. However, not only the combinations of the configurations explicitly described in the description of each embodiment, but also the configurations of the plurality of embodiments can be partially combined with each other as long as there is no problem with the combination, even if not explicitly stated. And the combinations not explicitly stated between the configurations described in the plurality of embodiments and modification examples are also considered to be disclosed by the following description.

[0118] In each of the above embodiments, the first bus bar in contact with the cooling member 90 corresponds to the main terminals 32P and 32N, and the second bus bar corresponds to the P bus bar 52P and the N bus bar 52N. However, contrary to this embodiment, the first bus bar may correspond to the P bus bar 52P and the N bus bar 52N, and the second bus bar may correspond to the main terminals 32P and 32N. In that case, it is desirable that the P bus bar 52P and the N bus bar 52N are located below the main terminals 32P and 32N. Also, both the first bus bar and the second bus bar may be in contact with the cooling member 90 together with the fastening member 80.

[0119] In each of the above embodiments, a step is formed at the boundary between the main terminal 32P and the fastening member 80 due to the protrusion of the side surface 812b of the bolt. On the contrary, the bolt 81 may be inserted and arranged on the bottom surface 32b of the bus bar so that the bottom surface 812a of the bolt and the bottom surface 32b of the bus bar are located in the same plane so as to eliminate the step. In this case, the contact portion 91 will be in contact with the bottom surface 812a of the bolt and the bottom surface 32b of the bus bar.

[0120] In each of the above-described embodiments, the cooling member 90 is in contact with the head 812 of the bolt 81. In contrast, the cooling member 90 may be in contact with the tip of the shaft portion 811. Also, the cooling member 90 may be in contact with the nut 82, or the cooling member 90 may be in contact with both the nut 82 and the bolt 81.

[0121] In each of the above-described embodiments, the nut 82 may be omitted, and the tip of the shaft portion 811 may be welded to the P bus bar 52P or the N bus bar 52N to fix the bolt 81. Also, the bolt 81 is not limited to being made of metal and may be made of resin. Further, the bolt 81 may be a stud bolt (embedded bolt) without the head 812.

[0122] In each of the above embodiments, the first bus bar and the second bus bar to which the bus bar cooling structure is applied are bus bars in a path for energizing between the upper and lower arm circuits 10 and the smoothing capacitor 6. In contrast, the first bus bar and the second bus bar may be applied to a bus bar in a path for energizing between the upper and lower arm circuits 10 and the motor generator 3 (motor). Also in this case, it is desirable that the cooling unit 93 is thermally connected to the first bus bar and the fastening member 80 while being electrically insulated from the first bus bar and the fastening member 80. When each of the windings 3a of the U phase, V phase, and W phase drops to the ground, the cooling member 90, the fastening member 80, and the bus bar exhibit the function of a Y capacitor.

[0123] In this case, the function of the Y capacitor shown by the dashed-dotted line in FIG. 15 is exhibited. That is, substantially speaking, it can be said that a Y capacitor Yu is connected between the output line 11 connected to the winding 3a of the U phase and the ground. Similarly, it can be said that a Y capacitor Yv is connected between the output line 11 connected to the winding 3a of the V phase and the ground, and a Y capacitor Yw is connected between the output line 11 connected to the winding 3a of the W phase and the ground.

[0124] In each of the above embodiments, the cooling member 90 includes the contact portion 91 and the electrical insulation portion 92. However, the contact portion 91 may be eliminated, and the electrical insulation portion 92 may be configured to contact the bottom surface 32b of the bus bar. In that case, it is desirable to employ a soft material for the electrical insulation portion 92 that can also contact the side surface 812b of the bolt. Alternatively, the electrical insulation portion 92 may be eliminated, and a material having electrical insulation properties may be employed for the contact portion 91. Further, in the second embodiment above, the electrical insulation portion 92 has the first extension portion and the second extension portion, but either one of the extension portions may be eliminated, or both of the extension portions may be eliminated.

[0125] In each of the above embodiments, the electrical device is applied to a power conversion device, but it may also be applied to a converter that converts a DC voltage into a DC voltage having a different value, for example, or a charging device. The converter is configured to include, for example, a reactor and the upper and lower arm circuits 10 described above. According to this configuration, step-up and step-down are possible.

[0126] (Disclosure of Technical Ideas) This specification discloses a plurality of technical ideas described in a plurality of claims listed below. Some claims may be described in a multiple dependent form in which a preceding claim is alternatively cited in a subsequent claim. Further, some claims may be described in a multiple dependent form that cites another multiple dependent form claim. The claims described in these multiple dependent forms define a plurality of technical ideas.

[0127] (Technical Idea 1) A first bus bar (32P, 32N) that forms an energization path, A second bus bar (52P, 52N) that forms the energization path together with the first bus bar, A fastening member (80) that fastens the first bus bar and the second bus bar to each other, A cooling member (90) that cools the heat generated in the first bus bar and the second bus bar with energization, The cooling member is an electrical device that is in contact with both the first bus bar and the fastening member.

[0128] (Technical idea 2) The first bus bar has a through hole (32a) into which the fastening member is inserted. The fastening member includes a caulking portion (814) that is plastically deformed in the radial direction of the through hole and caulked to the first bus bar. The electrical device according to Technical Idea 1.

[0129] (Technical idea 3) The fastening member includes a bolt (81). The cooling member is in contact with the head (812) of the bolt. The electrical device according to Technical Idea 1 or 2.

[0130] (Technical idea 4) The energization path is a path for energizing between the upper and lower arm circuits (10) and the smoothing capacitor (6). The cooling member includes a ground portion that has a ground potential. The ground portion is thermally connected to the first bus bar and the fastening member while being electrically insulated from the first bus bar and the fastening member. The electrical device according to any one of Technical Ideas 1 to 3.

[0131] (Technical idea 5) The cooling member includes a close contact portion (91) that is in close contact with the first bus bar and the fastening member in a state of being deformed following the boundary step between the first bus bar and the fastening member. The electrical device according to any one of Technical Ideas 1 to 4.

[0132] (Technical idea 6) The cooling member includes a cooling portion (93) that is at a lower temperature than the ambient temperature of the first bus bar, and an electrical insulating portion (92) disposed between the close contact portion and the cooling portion. The cooling unit is thermally connected to the first bus bar and the fastening member via the electrical insulation part and the contact part, and is the electrical device described in Technical Idea 5.

[0133] (Technical Idea 7) The contact part is regarded as the first contact part, The cooling member includes a second contact part (910) that is in close contact with the cooling part, The electrical insulation part is arranged between the first contact part and the second contact part, and is the electrical device described in Technical Idea 6.

[0134] (Technical Idea 8) The electrical insulation part has at least one of a first extension part (92b) extending along the side surface (93b) of the cooling part and a second extension part (92c) extending along the side surface (91b) of the contact part, and is the electrical device described in Technical Idea 6 or 7.

[0135] (Technical Idea 9) The fastening member fastens the first bus bar and the second bus bar, and includes a third bus bar (53) that forms the energization path together with the first bus bar and the second bus bar. The energization path includes an inverter path that branches from the part of the fastening member to the upper and lower arm circuits (10), a capacitor path that branches from the part of the fastening member to the smoothing capacitor (6), and a battery path that branches from the part of the fastening member to the DC power supply (2). The first bus bar, the second bus bar, and the third bus bar each form one of the inverter path, the capacitor path, and the battery path, and are the electrical devices described in any one of Technical Ideas 1 to 8.

[0136] (Technical Idea 10) The first bus bar forms the battery path, and is the electrical device described in Technical Idea 9.

[0137] (Technical Idea 11) The first bus bar forms the capacitor path, and is the electrical device described in Technical Idea 9.

[0138] (Technical idea 12) The energization path is a path for energizing between the upper and lower arm circuits (10) and the motor (3). The cooling member includes a ground portion that has a ground potential. The ground portion is thermally connected to the first bus bar and the fastening member while being electrically insulated from the first bus bar and the fastening member. The electrical device according to any one of Technical Ideas 1 to 11.

[0139] (Technical idea 13) The cooling member is used as a first cooling member. Separate from the first cooling member, a second cooling member (90x) is provided for cooling the heat generated in the first bus bar and the second bus bar due to energization. The second cooling member is in contact with both the second bus bar and the fastening member. The electrical device according to any one of Technical Ideas 1, 2, 4 to 12.

[0140] (Technical idea 14) The fastening member includes a bolt (81) and a nut (82). One of the first cooling member and the second cooling member is in contact with the head (812) of the bolt, and the other of the first cooling member and the second cooling member is in contact with the nut. The electrical device according to Technical Idea 13.

Explanation of reference numerals

[0141] 10 Upper and lower arm circuits, 32N, 32P First bus bar, 32a Through hole, 52N, 52P Second bus bar, 6 Smoothing capacitor, 53 Third bus bar, 80 Fastening member, 81 Bolt, 812 Head, 814 Crimping portion, 82 Nut, 90 Cooling member (first cooling member), 90x Second cooling member, 91 Contact portion, 910 Second contact portion, 91b Side surface, 92 Electrical insulation portion, 92b First extension portion, 92c Second extension portion, 93 Cooling portion, 93b Side surface.

Claims

1. The first busbars (32P, 32N) that form the current path, A second busbar (52P, 52N) that forms the current path together with the first busbar, A fastening member (80) that fastens the first busbar and the second busbar together, The system includes a cooling member (90) for cooling the heat generated in the first busbar and the second busbar when power is applied, The first busbar has a through hole (32a) into which the fastening member is inserted, The fastening member includes a crimping portion (814) that is plastically deformed in the radial direction of the through hole and crimped to the first busbar. The cooling member is an electrical device that is in contact with both the first busbar and the fastening member.

2. The electrical device according to claim 1, wherein the cooling member includes a contact portion (91) that is deformed to conform to the boundary step between the first busbar and the fastening member and is in close contact with the first busbar and the fastening member.

3. A first busbar (32P, 32N) that forms an energizing path, A second busbar (52P, 52N) that forms the current path together with the first busbar, A fastening member (80) that fastens the first busbar and the second busbar together, The system includes a cooling member (90) for cooling the heat generated in the first busbar and the second busbar when power is applied, The cooling member is in contact with both the first busbar and the fastening member. The cooling member includes an adhesion portion (91) that is deformed to conform to the boundary step between the first busbar and the fastening member and adheres closely to the first busbar and the fastening member.

4. The first busbar has a through hole (32a) into which the fastening member is inserted, The electrical device according to claim 3, wherein the fastening member includes a crimping portion (814) that is plastically deformed in the radial direction of the through hole and crimped to the first busbar.

5. The fastening member includes a bolt (81), The electrical device according to any one of claims 1 to 4, wherein the cooling member is in contact with the head (812) of the bolt.

6. The aforementioned current supply path is a path that supplies current between the upper and lower arm circuit (10) and the smoothing capacitor (6). The cooling member includes a ground portion which is at ground potential. The electrical device according to any one of claims 1 to 4, wherein the ground portion is thermally connected to the first busbar and the fastening member while being electrically insulated from the first busbar and the fastening member.

7. The cooling member includes a cooling section (93) that is at a lower temperature than the ambient temperature of the first busbar, and an electrical insulating section (92) disposed between the contact section and the cooling section. The electrical device according to any one of claims 2 to 4, wherein the cooling section is thermally connected to the first busbar and the fastening member via the electrical insulating section and the contact section.

8. The aforementioned contact portion is referred to as the first contact portion. The cooling member includes a second contact portion (910) that is in close contact with the cooling portion. The electrical device according to claim 7, wherein the electrical insulating portion is disposed between the first contact portion and the second contact portion.

9. The electrical device according to claim 7, wherein the electrical insulating portion has at least one of a first extended portion (92b) extending along the side surface (93b) of the cooling portion and a second extended portion (92c) extending along the side surface (91b) of the contact portion.

10. The third busbar (53) is fastened to the first busbar and the second busbar by the fastening member and together with the first busbar and the second busbar, forms the current-carrying path. The power supply path includes an inverter path that branches from the fastening member portion to the upper and lower arm circuit (10), a capacitor path that branches from the fastening member portion to the smoothing capacitor (6), and a battery path that branches from the fastening member portion to the DC power supply (2). The electrical device according to any one of claims 1 to 4, wherein the first busbar, the second busbar, and the third busbar each form one of the inverter path, the capacitor path, and the battery path.

11. The electrical device according to claim 10, wherein the first busbar forms the battery path.

12. The electrical device according to claim 10, wherein the first busbar forms the capacitor path.

13. The aforementioned power supply path is a path that supplies power between the upper and lower arm circuit (10) and the motor (3). The cooling member includes a ground portion which is at ground potential. The electrical device according to any one of claims 1 to 4, wherein the ground portion is thermally connected to the first busbar and the fastening member while being electrically insulated from the first busbar and the fastening member.

14. The cooling member is designated as the first cooling member. In addition to the first cooling member, a second cooling member (90x) is provided to cool the heat generated in the first busbar and the second busbar when power is applied. The electrical device according to any one of claims 1 to 4, wherein the second cooling member is in contact with both the second busbar and the fastening member.

15. The fastening member includes a bolt (81) and a nut (82). The electrical device according to claim 14, wherein one of the first cooling member and the second cooling member is in contact with the head (812) of the bolt, and the other of the first cooling member and the second cooling member is in contact with the nut.

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