Electrical device

Abstract

This electrical device comprises bus bars (40P, 50P, 40N, 50N), fastening members (110), an insulating member (161), and a heat dissipation member. Conductive members include first conductive pieces (40P, 40N) that form a current path, and second conductive pieces (50P, 50N) that form the current path together with the first conductive pieces. The fastening members each fasten the first conductive piece and the second conductive piece to each other. The insulating member includes a base (162) overlapping fastening portions (60A, 60B) between the first conductive pieces and the second conductive pieces, and a standing wall (163) rising from the base. The heat dissipation member is insulating, is provided on the base, and dissipates heat from the fastening portions to the base. The electrical device includes a plurality of conductive members and fastening members, at least two fastening portions overlap the heat dissipation member, and the standing wall is provided between two adjacent fastening portions.

Description

Electrical device Cross-reference to related applications

[0001] This application is based on Japanese Patent Application No. 2025-003744 filed in Japan on January 9, 2025, and the contents of the base application are incorporated herein by reference in their entirety.

[0002] The disclosure described in this specification relates to an electrical device.

[0003] In the conductive part fastening structure described in Patent Document 1, a plurality of conductive parts are electrically connected via a terminal block. The terminal block has a base made of a conductive resin and three conductive base nuts integrally formed with the base. The end face of the base nut is exposed from the base. A fastening hole is formed in one end face of the base nut. By fastening a fastening member to the fastening hole, a plurality of conductive parts are electrically and mechanically connected.

[0004] Three bus bars and three cable terminals are arranged on the base nut as conductive parts. The bus bar and the cable terminal are each fastened with a bolt.

[0005] Japanese Patent Application Laid-Open No. 2008-98007

[0006] When the fastening member is fastened, there is a concern that conductive pieces such as chips are generated during the fastening, and the adjacent conductive parts may be short-circuited by the conductive pieces.

[0007] In Patent Document 1, there was a risk that adjacent conductive parts would be short-circuited through the conductive pieces.

[0008] An object of the present disclosure is to provide an electrical device in which short-circuiting between adjacent conductive parts is suppressed.

[0009] An electrical device according to one aspect of the present disclosure comprises a conductive member including a first conductive piece that forms an energizing path and a second conductive piece that forms an energizing path together with the first conductive piece; a fastening member that fastens the first conductive piece and the second conductive piece together; an insulating member including a base that overlaps the fastening portion of the first conductive piece and the second conductive piece and a vertical wall rising from the base; and an insulating heat dissipation member provided on the base that dissipates heat from the fastening portion to the base, wherein there are a plurality of conductive members and fastening members, at least two fastening portions overlap the heat dissipation member, and a vertical wall is provided between two adjacent fastening portions.

[0010] The presence of vertical walls makes it less likely for conductive pieces generated when fastening members to conductive members to short-circuit adjacent conductive members. Therefore, vertical walls can suppress short circuits between adjacent conductive members via conductive pieces.

[0011] The reference numbers in parentheses above merely indicate the correspondence with the configurations described in the embodiments below, and do not in any way limit the technical scope.

[0012] This is a circuit diagram showing the circuit configuration and drive system. This is a plan view showing the power converter. This is a cross-sectional view along the line III-III in Figure 2. This is a plan view showing the fastening of the capacitor busbar, the first busbar and the second busbar. This is a perspective view of the insulating member. This is a cross-sectional view along the line VI-VI in Figure 4. This is a cross-sectional view along the line VII-VII in Figure 4. This is an enlarged view of the fastening portion between the first busbar and the second busbar. This is a top view of the fastening member. This is a cross-sectional view of the fastening member before crimping. This is a cross-sectional view of the fastening member after crimping. This is a cross-sectional view illustrating the chips. This is a cross-sectional view of the second embodiment. This is a cross-sectional view of the third embodiment. This is a plan view of the fastening portion of the fourth embodiment. This is a cross-sectional view along the line XVI-XVI in Figure 15.

[0013] Several embodiments will be described below with reference to the drawings. In each embodiment, the same reference numerals are used for corresponding components, and redundant explanations may be omitted. If only a part of the configuration is described in each embodiment, the configuration of other embodiments described earlier can be applied to the other parts of that configuration. Furthermore, in addition to the combinations of configurations explicitly stated in the description of each embodiment, configurations from multiple embodiments can be partially combined even if not explicitly stated, as long as there are no particular problems with the combination.

[0014] The electrical device of this embodiment is, for example, a power conversion device applied to a mobile body that uses a rotating electric machine as its drive source. Examples of mobile bodies include electric vehicles such as battery electric vehicles (BEVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs), electric aircraft such as drones and electric vertical take-off and landing aircraft (eVTOLs), ships, construction machinery, and agricultural machinery. Examples of its application to vehicles will be described below.

[0015] (First Embodiment) First, the general configuration of the vehicle's drive system will be described based on Figure 1.

[0016] <Vehicle Drive System> As shown in Figure 1, the vehicle drive system 1 includes a DC power supply 2, a motor generator 3, and a power converter 4.

[0017] 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 the vehicle's driving source, i.e., an electric motor. The motor generator 3 also 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.

[0018] <Circuit Configuration of Power Converter> Figure 1 shows the circuit configuration of the power converter 4. The power converter 4 of this embodiment includes an inverter 5 and a smoothing capacitor 6 as a power conversion circuit. The power converter 4 may further include a drive circuit 7. The power converter 4 is sometimes simply referred to as an electrical device. The smoothing capacitor 6 will be described first.

[0019] The smoothing capacitor 6 primarily smooths the DC voltage supplied from the DC power supply 2. The smoothing capacitor 6 is connected to the P line 8, which is the high-potential power line, and the N line 9, which is the low-potential power line. The P line 8 is connected to the positive terminal of the DC power supply 2, and the N line 9 is connected to the negative terminal of the DC power supply 2. The positive terminal of the smoothing capacitor 6 is connected to the P line 8 between the DC power supply 2 and the inverter 5. The negative terminal 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. The smoothing capacitor 6 is provided by a capacitor 70. Details of the capacitor 70 will be described later.

[0020] The inverter 5 is a DC-AC conversion circuit. The inverter 5 converts a DC voltage to a three-phase AC voltage according to switching control by a control circuit (not shown) and outputs it to the motor generator 3. This drives the motor generator 3 to generate a predetermined torque. During regenerative braking of the vehicle, the inverter 5 receives rotational force from the wheels and converts the three-phase AC voltage generated by the motor generator 3 into a DC voltage according to 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.

[0021] The inverter 5 is configured with 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 connected in series between the P line 8 and the N line 9, with the upper arm 10H on the P line 8 side.

[0022] The connection point between the upper arm 10H and the lower arm 10L, i.e., the midpoint of the upper and lower arm circuits 10, is connected to the corresponding phase winding 3a in the motor generator 3 via the output line 11. Of 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.

[0023] The upper and lower arm circuit 10 (10U, 10V, 10W) ​​has a series circuit 12. The series circuit 12 in the upper and lower arm circuit 10 may be one or more. If there are multiple series circuits 12, they are connected in parallel to each other to form one phase of the upper and lower arm circuit 10. The series circuit 12 is configured by connecting the switching element on the upper arm 10H side and the switching element on the lower arm 10L side in series between the P line 8 and the N line 9. The upper and lower arm circuit 10 is provided by a semiconductor module 30. The inverter 5 is composed of three semiconductor modules 30. Details of the semiconductor modules 30 will be explained later.

[0024] The number of high-side switching elements and low-side switching elements constituting the series circuit 12 is not particularly limited. There may be one or more. The series circuit 12 in this embodiment has two switching elements on the high-side and two switching elements on the low-side. The two high-side switching elements are connected in parallel, and the two low-side switching elements are connected in parallel to constitute one series circuit 12. In other words, each of the six arms 10H and 10L of the three-phase upper and lower arm circuits 10 is composed of two switching elements connected in parallel to each other.

[0025] In this embodiment, n-channel type MOSFETs 13 are used as each switching element. MOSFET is an abbreviation for Metal Oxide Semiconductor Field Effect Transistor. The two high-side MOSFETs 13 connected in parallel are turned on and off at the same timing by a common gate drive signal (drive voltage). The two low-side MOSFETs 13 connected in parallel are turned on and off at the same timing by a common gate drive signal (drive voltage).

[0026] Each of the MOSFETs 13 has a freewheeling diode 14 (hereinafter referred to as FWD14) connected in antiparallel. In the case of MOSFET 13, FWD14 may be a parasitic diode (body diode) or an external diode. On the upper arm 10H, the drain of MOSFET 13 is connected to the P line 8. On the lower arm 10L, the source of MOSFET 13 is connected to the N line 9. The drains of MOSFET 13 on the upper arm 10H and the drains of MOSFET 13 on the lower arm 10L are interconnected. The anode of FWD14 is connected to the source of the corresponding MOSFET 13, and its cathode is connected to the drain.

[0027] Note that the switching element is not limited to MOSFET 13. For example, an IGBT may be used. IGBT is an abbreviation for Insulated Gate Bipolar Transistor. In the case of an IGBT, the FWD 14 is also connected in antiparallel.

[0028] The drive circuit 7 drives the switching elements that constitute the power conversion circuit, such as the inverter 5. Based on the drive command from the control circuit, the drive circuit 7 supplies a drive voltage to the gate of the corresponding MOSFET 13. By applying the drive voltage, the drive circuit drives the corresponding MOSFET 13, i.e., turns it on or off. The drive circuit is sometimes referred to as a driver. The drive circuit 7 is provided by the circuit board 80.

[0029] The power converter 4 may further include a control circuit for switching elements as a power conversion circuit. The control circuit generates drive commands for operating the MOSFET 13 and outputs them to the drive circuit 7. The control circuit generates drive commands based on, for example, torque requests 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 located within the higher-level ECU. The control circuit may be mounted on the circuit board 80.

[0030] <Structure of the Power Converter> Figure 2 is a plan view showing the power converter 4 of this embodiment. In Figure 2, the circuit board 80 is omitted so that the arrangement of the semiconductor module 30 can be seen. Figure 3 is a cross-sectional view taken along the line III-III in Figure 2. In Figure 3, for convenience, only the semiconductor element and the encapsulant are shown as the main body 31 of the semiconductor module 30. Also, the portion of the external connection terminal 32 of the semiconductor module 30 that is sealed in the encapsulant is omitted.

[0031] In the following, the direction in which the three semiconductor modules 30 are aligned is referred to as the X direction. The Z direction is perpendicular to the X direction and is the stacking direction of the base 21 and the semiconductor modules 30. The Y direction is perpendicular to both the X and Z directions. The X, Y, and Z directions are in a positional relationship that is orthogonal to each other. A plan view from the Z direction is sometimes simply referred to as a plan view. The direction perpendicular to the Z direction is sometimes referred to as the planar direction. When describing the relative positions of two components, the position of the component closer to the base 21 in the Z direction is sometimes referred to as downward, and the position of the component further from the base 21 is sometimes referred to as upward. The X direction corresponds to the first direction. The Y direction corresponds to the second direction. The Z direction corresponds to the stacking direction.

[0032] In addition to the configuration described above, the power converter 4 includes a housing 20, first busbars 40P and 40N, second busbars 50P and 50N, fastening cooler 60, terminal block 90, and a plurality of fastening members 110. The power converter 4 of this embodiment includes a housing 20, three semiconductor modules 30, first busbars 40P and 40N, second busbars 50P and 50N, fastening cooler 60, capacitor 70, circuit board 80, terminal block 90, and fastening members 110.

[0033] The first busbars 40P and 40N are conductive parts that form part of the current path between the capacitor 70 and the DC power supply 2. The second busbars 50P and 50N are conductive parts that form the remaining current path between the capacitor 70 and the DC power supply 2. The capacitor 70 and the DC power supply 2 are electrically connected via the first busbars 40P and 40N and the second busbars 50P and 50N.

[0034] The first busbars 40P and 40N include a P-side first busbar 40P that electrically connects the positive terminal of capacitor 70 to the positive terminal of DC power supply 2, and an N-side first busbar 40N that electrically connects the negative terminal of capacitor 70 to the negative terminal of DC power supply 2. The second busbars 50P and 50N include a P-side second busbar 50P that electrically connects the positive terminal of capacitor 70 to DC power supply 2, and an N-side second busbar 50N that electrically connects the negative terminal of capacitor 70 to DC power supply 2. The first busbars 40P and 40N correspond to the first conductive piece. The second busbars 50P and 50N correspond to the second conductive piece.

[0035] The positive terminal of capacitor 70 and the positive terminal of DC power supply 2 are electrically connected via P-side first busbar 40P and P-side second busbar 50P. The negative terminal of capacitor 70 and the negative terminal of DC power supply 2 are electrically connected via N-side first busbar 40N and N-side second busbar 50N. P-side first busbar 40P and P-side second busbar 50P are sometimes collectively referred to as P-side busbars 40P and 50P. N-side first busbar 40N and N-side second busbar 50N are sometimes collectively referred to as N-side busbars 40N and 50N. P-side busbars 40P and 50P, and N-side busbars 40N and 50N correspond to conductive members. Power converter 4 has a plurality of conductive members.

[0036] The fastening cooler 60 cools the fastening points between conductive parts. As will be explained in detail later, the fastening cooler 60 is provided on the base 21 and cools the fastening points from below. The fastening cooler 60 supports two or more fastening points from below. The fastening cooler 60 has a base for cooling the fastening points and a heat dissipation member for dissipating heat from the fastening points to the base. The fastening cooler 60 has a first fastening cooler 160 and a second fastening cooler 260.

[0037] <Enclosure> The enclosure 20 has a base 21 having a plate thickness in the Z direction and a wall portion 23 erected from the base 21. The base 21 is electrically connected to the body ground of a chassis or the like. The base 21 provides ground potential. The base 21 has a surface 21A and a back surface 21B aligned in the Z direction. The surface 21A and the back surface 21B together are sometimes referred to as the main surfaces 21A and 21B.

[0038] The front surface 21A is the surface facing the circuit board 80 and is the mounting surface on which the semiconductor module 30, capacitor 70, terminal block 90, and second fastening cooler 260 are mounted. The back surface 21B is the mounting surface on which the first busbars 40P and 40N, the second busbars 50P and 50N, and the first fastening cooler 160 are mounted.

[0039] The base 21 is a support member that supports the semiconductor module 30, the first busbars 40P and 40N, the second busbars 50P and 50N, the fastening cooler 60, the capacitor 70, and the terminal block 90. ​​The base 21 is formed using a metal material such as aluminum. The base 21 has a cooler 22. The cooler 22 is constructed using the base 21. The cooler 22 may have a flow path for a coolant, or it may be a heat dissipation member with heat dissipation fins.

[0040] As an example, the cooler 22 of this embodiment includes a flow path 22A formed inside the base 21. A refrigerant flows through the flow path 22A. As the refrigerant, for example, a phase-changing refrigerant such as water or ammonia, or a non-phase-changing refrigerant such as ethylene glycol, can be used. In this embodiment, the cooler 22 is positioned to overlap the semiconductor module 30 in the Z direction. The cooler 22 cools the semiconductor module 30 from the lower back surface 31B. The cooler 22 extends in the planar direction.

[0041] The base 21 is provided as part of a housing 20 that houses components of the power conversion device 4. The base 21 defines a housing space together with a wall portion 23. The base 21 is provided as a partition wall of the housing 20. The wall portion 23 has a first wall 23A and a third wall 23C spaced apart in the X direction, and a second wall 23B and a fourth wall 23D spaced apart in the Y direction. The first wall 23A, the second wall 23B, the third wall 23C, and the fourth wall 23D are connected in this order in a clockwise direction. The wall portion 23 extends annularly along the edge of the base 21.

[0042] The wall portion 23 has a front side wall portion 231 erected from the front surface 21A and a back side wall portion 232 erected from the back surface 21B. A first housing space 26 is partitioned by the base 21 and the front side wall portion 231. A second housing space 27 is partitioned by the base 21 and the back side wall portion 232. Note that the housing 20 may have a cover that closes two openings. The first housing space 26 and the second housing space 27 may be partitioned by the base 21, the wall portion 23, and the cover.

[0043] The three semiconductor modules 30 are arranged in order of a U-phase semiconductor module 30U, a V-phase semiconductor module 30V, and a W-phase semiconductor module 30W from the first wall 23A toward the third wall 23C. A capacitor 70 and a terminal block 90 are arranged so as to sandwich the three semiconductor modules 30. The capacitor 70 is arranged on the second wall 23B side of the semiconductor module 30 in the Y direction. The terminal block 90 is arranged on the fourth wall 23D side of the semiconductor module 30 in the Y direction.

[0044] <Semiconductor Module> The semiconductor module 30 of the present embodiment provides one series circuit 12, that is, an upper and lower arm circuit 10 for one phase. The three semiconductor modules 30 include 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.

[0045] The three semiconductor modules 30 have a common structure with each other. Each semiconductor module 30 includes a main body 31 and external connection terminals 32 protruding from the main body 31. The main body 31 includes semiconductor elements 33, a sealing body 34, and the like. The semiconductor elements 33 of the present embodiment include two semiconductor elements 33H that provide switching elements on the high side of the series circuit 12 and two semiconductor elements 33L that provide switching elements on the low side of the series circuit 12.

[0046] 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, for example, a substantially rectangular planar shape. The sealing body 34 forms the outer contour of the main body 31. The main body 31 has a front surface 31A facing the circuit board 80, a back surface 31B facing the base 21 on the back side of the front surface 31A, and side surfaces 31C connecting the front surface 31A and the back surface 31B. Among the side surfaces 31C, the one located on the capacitor 70 side may be referred to as one side surface 311C, and the one located on the terminal block 90 side may be referred to as the other side surface 312C.

[0047] The external connection terminals 32 include main terminals 32P, 32N, 32O electrically connected to the main electrodes of the semiconductor elements 33 and signal terminals. 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 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 32P may be referred to as a P terminal, a high-potential power supply terminal, a positive electrode terminal, or the like. The main terminal 32N may be referred to as an N terminal, a low-potential power supply terminal, a negative electrode terminal, or the like. The main terminal 32O may be referred to as an O terminal, an output terminal, an AC terminal, or the like.

[0048] The main terminals 32P, 32N, and 32O are plate-shaped conductive parts. The main surfaces of the main terminals 32P, 32N, and 32O face the surface 21A in the Z direction. The main terminals 32P and 32N protrude outward from one side surface 311C of the main body 31. The protruding portions of the main terminals 32P and 32N are arranged side by side in the X direction. The main terminals 32P and 32N are connected to the corresponding capacitor busbars 71P and 71N via fastening members 110. The main terminal 32P and capacitor busbar 71P together are sometimes referred to as a conductive member. The main terminal 32N and capacitor busbar 71N together are sometimes referred to as a conductive member.

[0049] The main terminals 32O protrude outward from the other side 312C of the main body 31. The protruding portions of the three main terminals 32O are arranged in a line in the X direction. The main terminals 32O and the corresponding internal busbars 91 are connected via fastening members 110. The main terminals 32O are electrically connected to the corresponding windings 3a of the motor generator 3 via the internal busbars 91.

[0050] <Capacitor> The capacitor 70 comprises a case, a capacitor element housed in the case, and P-side capacitor busbars 71P and N-side capacitor busbars 71N connected to the capacitor element. In the drawing, the capacitor 70 is shown in a simplified form. The P-side capacitor busbar 71P and N-side capacitor busbars 71N are sometimes simply referred to as capacitor busbars 71P and 71N.

[0051] As an example, the capacitor element in this 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 ends in the Z direction. The P-side capacitor busbar 71P is connected to the positive electrode. The N-side capacitor busbar 71N is connected to the negative electrode.

[0052] The capacitor busbars 71P and 71N are plate-shaped conductive parts. The capacitor busbars 71P and 71N are connected to their corresponding electrodes by soldering, resistance welding, laser welding, or the like. The capacitor busbars 71P and 71N have one end and the other end. One end of the capacitor busbars 71P and 71N has its main surface facing the surface 21A in the Z direction. One end of the capacitor busbars 71P and 71N is drawn out towards the semiconductor module 30 in the Y direction. As described above, one end of the capacitor busbars 71P and 71N is connected to the corresponding main terminals 32P and 32N via the fastening member 110.

[0053] The other ends of the capacitor busbars 71P and 71N are led out into the second housing space 27 in the Z direction. The base 21 is provided with holes (not shown). The other ends of the capacitor busbars 71P and 71N are led out from the first housing space 26 to the second housing space 27 through the holes. On the second housing space 27 side, the main surfaces of the other ends of the capacitor busbars 71P and 71N face the back surface 21B in the Z direction.

[0054] The other end of the P-side capacitor busbar 71P and the other end of the N-side capacitor busbar 71N are arranged side by side in the Y direction. The other ends of the capacitor busbars 71P and 71N are connected to one end of the corresponding first busbars 40P and 40N via a fastening member 110. The other ends of the capacitor busbars 71P and 71N, the first busbars 40P and 40N, and the fastening member 110 are provided in the second housing space 27 so as to overlap with the capacitor 70 in the Z direction.

[0055] The first busbars 40P and 40N are plate-shaped conductive parts. The main surfaces of the first busbars 40P and 40N face the back surface 21B in the Z direction. The first busbars 40P and 40N extend in the X direction along the back surface 21B. The first busbars 40P and 40N have one end and the other end. As described above, one end of the first busbars 40P and 40N is connected to the other end of the corresponding capacitor busbars 71P and 71N via a fastening member 110. The other end of the first busbars 40P and 40N is connected to one end of the corresponding second busbars 50P and 50N via a fastening member 110. The second busbars 50P and 50N are also provided in the second housing space 27 so as to overlap with the capacitor 70 in the Z direction.

[0056] The second busbars 50P and 50N are plate-shaped conductive parts. The main surfaces of the second busbars 50P and 50N face the back surface 21B in the Z direction. The second busbars 50P and 50N extend in a planar direction along the back surface 21B. The second busbars 50P and 50N have one end and the other end. As described above, one end of the second busbars 50P and 50N is connected to the other end of the corresponding first busbars 40P and 40N via a fastening member 110.

[0057] More specifically, the fastening configuration of the first busbars 40P and 40N and the second busbars 50P and 50N is as follows: one end of the P-side first busbar 40P is connected to the other end of the P-side capacitor busbar 71P via a fastening member 110. The other end of the P-side first busbar 40P is connected to one end of the P-side second busbar 50P via a fastening member 110.

[0058] One end of the N-side first busbar 40N is connected to the other end of the N-side capacitor busbar 71N via a fastening member 110. The other end of the N-side first busbar 40N is connected to one end of the N-side second busbar 50N via a fastening member 110. The other ends of the second busbars 50P and 50N are electrically connected to a connector (not shown). Power is supplied to the power converter 4 when the DC power supply 2 is connected to the connector. The other ends of the second busbars 50P and 50N are electrically connected to the DC power supply 2 via the connector.

[0059] <Terminal Block> The terminal block 90 is provided in the current path between the semiconductor module 30 and the motor generator 3. The terminal block 90 has an internal busbar 91, a current sensor 92, and a main body 93. The internal busbar 91 is a conductive part that makes up part of the output line 11. The current sensor 92 measures the amount of current passing through the internal busbar 91. The main body 93 is a resin component that encloses part of the internal busbar 91 and the current sensor 92.

[0060] The internal busbar 91 is a plate-shaped conductive part. The main surface of the internal busbar 91 faces the surface 21A in the Z direction. One end of the internal busbar 91 is drawn out toward the semiconductor module 30 in the Y direction. One end of the internal busbar 91 and the corresponding main terminal 32O are connected via a fastening member 110. Although not shown in the drawing, the other end of the internal busbar 91 is drawn out toward the fourth wall 23D in the Y direction. The other end of the internal busbar 91 is electrically connected to the motor generator 3 via wiring, etc. (not shown).

[0061] <Fastening points and fastening cooling body> In the first housing space 26, the fastening points between the main terminal 32P and the P-side capacitor busbar 71P, and the fastening points between the main terminal 32N and the N-side capacitor busbar 71N, overlap the base 262. A second fastening cooling body 260 is provided so that the base 262 overlaps below the two fastening points. The structure of the second fastening cooling body 260 will be explained later.

[0062] As described above, in the second accommodation space 27, the fastening portion between the other end of the P-side first busbar 40P and one end of the P-side second busbar 50P, and the fastening portion between the N-side first busbar 40N and one end of the N-side second busbar 50N, overlap the base 162. The first fastening cooler 160 is provided so that the base 162 overlaps below the two fastening portions. The structure of the first fastening cooler 160 will be described later.

[0063] Figure 4 is a plan view showing the fastening of capacitor busbars 71P and 71N, first busbars 40P and 40N, and second busbars 50P and 50N. Figure 5 is a perspective view of the insulating member 161 of the first fastening cooler 160. Figure 6 is a cross-sectional view along the line VI-VI in Figure 4. Figure 7 is a cross-sectional view along the line VII-VII in Figure 4. Figure 8 is an enlarged view of the fastening portion of the first busbars 40P and 40N and the second busbars 50P and 50N.

[0064] <First Fastening Cooling Element> The first busbars 40P and 40N, and the second busbars 50P and 50N generate heat when energized. In particular, the fastening areas have high thermal resistance and generate a large amount of heat. For this reason, the power converter 4 has a fastening cooling element 60 that efficiently dissipates the heat. The power converter 4 has a first fastening cooling element 160. The first fastening cooling element 160 is provided in the second housing space 27 so as to overlap with the capacitor 70 in the Z direction.

[0065] The first fastening cooler 160 has an insulating member 161 and a heat dissipation member 169. The insulating member 161 has a base 162, ribs 163, a first flange 164, a second flange 165, a third flange 166, a positioning portion 167, and recesses 168A and 168B. The base 162 has a plate thickness in the Z direction. The base 162 has a surface 162A facing the first busbars 40P and 40N and the second busbars 50P and 50N, and a back surface 162B facing the base 21. The base 162 is substantially rectangular in plan view. The ribs 163, first flange 164, second flange 165, and third flange 166 are connected to the base 162. These extend in the Z direction so as to rise from the surface 162A. The ribs 163 correspond to vertical walls.

[0066] The base 162 has a first edge 172A facing the first wall 23A, a second edge 172B facing the second wall 23B, a third edge 172C facing the third wall 23C, and a fourth edge 172D facing the fourth wall 23D. A first flange 164 is provided on a part of the third edge 172C and on the fourth edge 172D. A second flange 165 is provided on a part of the first edge 172A. A third flange 166 is provided on a part of the second edge 172B. Positioning portions 167 are provided on the first flange 164 and the second flange 165.

[0067] Hereinafter, the fastening portion between the P-side first busbar 40P and the P-side second busbar 50P may be referred to as the first fastening portion 60A. At the first fastening portion 60A, the other end of the P-side first busbar 40P and one end of the P-side second busbar 50P are stacked in the Z direction, and the two are fastened together by the fastening member 110. The fastening portion between the N-side first busbar 40N and the N-side second busbar 50N may be referred to as the second fastening portion 60B. At the second fastening portion 60B, the other end of the N-side first busbar 40N and one end of the N-side second busbar 50N are stacked in the Z direction, and the two are fastened together by the fastening member 110. In the drawings, the first fastening portion 60A and the second fastening portion 60B are enclosed by dashed lines.

[0068] The base 162 overlaps the first fastening portion 60A and the second fastening portion 60B in the Z direction. The base 162 has a first recess 168A at the position overlapping the first fastening portion 60A, recessed from the surface 162A toward the back surface 162B. The base 162 has a second recess 168B at the position overlapping the second fastening portion 60B, recessed from the surface 162A toward the back surface 162B. The first recess 168A and the second recess 168B have the same shape in plan view.

[0069] As shown in Figure 5, the first recess 168A and the second recess 168B have a bowl shape in plan view. The first recess 168A and the second recess 168B are positioned on the side of the first edge 172A side of the center of the base 162 in the X direction, such that their edges overlap the first edge 172A. The edge corresponds to the rim of a bowl. The depth of the first recess 168A and the second recess 168B is less than half the length of the base 162 in the X direction.

[0070] Furthermore, the first recess 168A and the second recess 168B are located on the fourth edge 172D side of the center of the base 162 in the Y direction. The first recess 168A and the second recess 168B are located together on the fourth edge 172D side. In a plan view, the first recess 168A and the second recess 168B are located side by side in the Y direction. The combined length of the width of the first recess 168A and the width of the second recess 168B is less than half the length of the base 162 in the Y direction. The first recess 168A is located on the fourth edge 172D side of the second recess 168B. A portion of the rib 163 is provided between the first recess 168A and the second recess 168B.

[0071] The rib 163 has a first extension 163A and a second extension 163B. The first extension 163A and the second extension 163B are made of the same material. The first extension 163A and the second extension 163B are continuous in the direction of extension. The first extension 163A extends in the X direction. The second extension 163B extends in the Y direction.

[0072] A first extension 163A is provided between the first recess 168A and the second recess 168B. The first extension 163A extends from the first edge 172A toward the third edge 172C. The first extension 163A is connected to the second extension 163B at its tip on the third edge 172C side. The second extension 163B extends in the Y direction toward the second edge 172B. The second extension 163B is connected to the second edge 172B at its tip on the second edge 172B side.

[0073] The third flange 166 described above is connected to the tip of the second extension 163B on the second edge 172B side. The third flange 166 extends along the second edge 172B to the third edge 172C. As a result, the rib 163 and the third flange 166 are integrally connected in the extension direction. The base 162 is divided into two regions by the rib 163 and the third flange 166. The first region 181, which is the region on the third edge 172C and fourth edge 172D side, has a roughly L-shape in plan view. The second region 182, which is the region on the first edge 172A and second edge 172B side, has a roughly rectangular shape in plan view.

[0074] The first region 181 is the region where the P-side busbars 40P and 50P are provided. As shown in Figure 4, the P-side first busbar 40P extends in the X direction. The P-side second busbar 50P extends in a roughly Z shape in plan view. The P-side second busbar 50P has a first extension 501P extending in the X direction, a second extension 502P extending in the Y direction, and a third extension 503P extending in the X direction. The other end of the P-side first busbar 40P and the first extension 501P are stacked in the Z direction. The other end of the P-side first busbar 40P and the first extension 501P are fastened together by a fastening member 110. In plan view, the P-side busbars 40P and 50P extend in a roughly Z shape.

[0075] The first flange 164 is provided in a roughly L-shape, extending from the third edge 172C to the fourth edge 172D, along the side surface of the P-side busbars 40P and 50P. In the planar direction, the P-side busbars 40P and 50P are sandwiched between the rib 163 and the first flange 164. The first flange 164 has a first flange extension 164A extending along the fourth edge 172D and a second flange extension 164B extending along the third edge 172C. The first extension 163A and the first flange extension 164A face each other in the Y direction. The second extension 163B and the second flange extension 164B face each other in the X direction. The first flange extension 164A corresponds to the first opposing part. The second flange extension 164B corresponds to the second opposing part.

[0076] The second region 182 is the region where the N-side busbars 40N and 50N are provided. The N-side first busbar 40N extends in the X direction. The N-side second busbar 50N extends in the Y direction. The other end of the N-side first busbar 40N and one end of the N-side second busbar 50N are stacked in the Z direction. The other end of the N-side first busbar 40N and one end of the N-side second busbar 50N are fastened together by a fastening member 110. In a plan view, the N-side busbars 40N and 50N extend in a roughly L-shape.

[0077] A second flange 165 is provided on the first edge 172A so as to follow the side surface of the N-side busbars 40N and 50N. The second flange 165 extends in the Y direction. The second extension 163B and the second flange 165 face each other in the X direction. In the planar direction, the N-side busbars 40N and 50N are sandwiched between the second extension 163B and the second flange 165.

[0078] In the Y direction, a first extension 163A is provided between the first fastening portion 60A and the second fastening portion 60B. In the X direction, a second extension 163B is provided between the second fastening portion 60B and the second extension 502P.

[0079] The positioning portion 167 defines its own position relative to the base 21. The positioning portion 167 has an extension portion 167A that extends in the planar direction from the flanges 164 and 165, and a hole 167B provided in the extension portion 167A. The base 21 has a positioning pin that defines the position of the insulating member 161. The positioning pin extends in the Z direction from the back surface 21B. The position of the insulating member 161 in the planar direction is defined by inserting the positioning pin into the hole 167B.

[0080] The heat dissipation member 169 is made of a material with higher thermal conductivity than the insulating member 161. The heat dissipation member 169 has insulating properties. The heat dissipation member 169 is softer than the insulating member 161. The heat dissipation member 169 is flexible enough to deform when an external force is applied. In this embodiment, the heat dissipation member 169 is a gap filler.

[0081] The gap filler is viscous before curing. Before curing, the gap filler has a viscosity sufficient to hold conductive fragments generated by the friction of the busbars. Note that thermal conductive grease or thermal conductive gel may be used for the heat dissipation member 169. Thermal conductive grease or thermal conductive gel has insulating properties and a viscosity sufficient to hold conductive fragments generated from the busbars. The conductive fragments are sometimes referred to as chips 100. Details of the chips 100 will be explained later.

[0082] As shown in Figure 6, heat dissipation members 169 are provided in the first recess 168A and the second recess 168B, respectively. The heat dissipation members 169 are housed in the first recess 168A and the second recess 168B. The types of heat dissipation members 169 provided in the first recess 168A and the second recess 168B may be different. Hereinafter, the heat dissipation member 169 provided in the first recess 168A may be referred to as heat dissipation member 269, and the heat dissipation member 169 provided in the second recess 168B may be referred to as heat dissipation member 369.

[0083] As described above, a first recess 168A is provided so as to overlap the first fastening portion 60A. A heat dissipation member 269 is provided in the first recess 168A. The movement of the heat dissipation member 269 is restricted by the first recess 168A. The first extension 501P and the fastening member 110 are in close contact with the heat dissipation member 269. The heat dissipation member 269 dissipates the heat from the first fastening portion 60A and the fastening member 110 to the base 162. The heat dissipation member 269 is soft enough to be in close contact with the first extension 501P and the fastening member 110, so it can effectively dissipate heat.

[0084] A second recess 168B is provided so as to overlap the second fastening portion 60B. A heat dissipation member 369 is provided in the second recess 168B. The movement of the heat dissipation member 369 is restricted by the second recess 168B. One end of the N-side second busbar 50N and the fastening member 110 are in close contact with the heat dissipation member 369. The heat dissipation member 369 dissipates the heat from the second fastening portion 60B and the fastening member 110 to the base 162. The heat dissipation member 369 is soft enough to be in close contact with the second fastening portion 60B and the fastening member 110, so it can effectively dissipate heat.

[0085] The first fastening portion 60A and the second fastening portion 60B are aligned in the Y direction. The first fastening portion 60A and the second fastening portion 60B have width in the Y direction. The first recess 168A and the second recess 168B also have width in the Y direction. The width of the first recess 168A in the Y direction is wider than the width of the first fastening portion 60A in the Y direction. The heat dissipation member 269 has an overlapping portion 269A that overlaps with the first fastening portion 60A in the Z direction, and non-overlapping portions 269B and 269C that do not overlap with the first fastening portion 60A in the Z direction.

[0086] In a plan view, the non-overlapping portions 269B and 269C are visible from both sides of the first fastening portion 60A in the Y direction. Non-overlapping portion 269B is visible from the side of the first fastening portion 60A on the first extension portion 163A side. Non-overlapping portion 269B is provided between the first fastening portion 60A and the first extension portion 163A. Non-overlapping portion 269C is visible from the side of the first fastening portion 60A on the first flange extension portion 164A side. Non-overlapping portion 269C is provided between the first fastening portion 60A and the first flange extension portion 164A. Non-overlapping portions 269B and 269C are exposed to the outside air.

[0087] Similarly, the width of the second recess 168B in the Y direction is wider than the width of the second fastening portion 60B in the Y direction. The heat dissipation member 369 has an overlapping portion 369A that overlaps with the second fastening portion 60B in the Z direction, and non-overlapping portions 369B, 369C, and 369D that do not overlap with the second fastening portion 60B in the Z direction. In a plan view, the non-overlapping portions 369B and 369C are visible from both sides of the second fastening portion 60B in the Y direction. The non-overlapping portion 369D is visible from the side of the second fastening portion 60B in the X direction.

[0088] The non-overlapping portion 369B is visible from the side of the second fastening portion 60B on the first extension portion 163A side. In the Y direction, the non-overlapping portion 369B is provided between the second fastening portion 60B and the first extension portion 163A. The non-overlapping portion 369C is visible from the side of the second fastening portion 60B on the second flange 165 side. In the Y direction, the non-overlapping portion 369C is provided between the second fastening portion 60B and the second flange 165.

[0089] Furthermore, the non-overlapping portion 369D is visible from the side of the second fastening portion 60B on the second extension portion 163B side. With respect to the Y direction, the non-overlapping portion 369D is provided between the second fastening portion 60B and the second extension portion 163B. The non-overlapping portions 369B, 369C, and 369D are exposed to the outside air.

[0090] <Busbar Connection Structure> The fastening member 110 is composed of a bolt 111 and a nut 116. The bolt 111 and nut 116 are made of metal. Through holes 40A are formed in the first busbars 40P and 40N, and through holes 50A are formed in the second busbars 50P and 50N. The other ends of the first busbars 40P and 40N and one end of the second busbars 50P and 50N are stacked in the Z direction so that the through holes 40A and 50A are in communication.

[0091] In this embodiment, the second busbars 50P and 50N are positioned closer to the base 162 than the first busbars 40P and 40N. The bolts 111 are inserted from the side of the second busbars 50P and 50N. The bolts 111 are inserted into the through holes 40A and 50A. The first busbars 40P and 40N and the second busbars 50P and 50N are fastened together by tightening the inserted bolts 111 in the Z direction with nuts 116. The components are stacked in the order of head 113, second busbars 50P and 50N, first busbars 40P and 40N, and nut 116 from the base 162 side. The head 113 of the bolt 111 is in contact with the second busbars 50P and 50N. The nut 116 is in contact with the first busbars 40P and 40N.

[0092] The detailed structure of the bolt 111 will now be described. The bolt 111 has a shaft portion 112, a head portion 113, an enlarged diameter portion 114, and a crimping portion 115. Figure 9 is a top view of the fastening member 110. Figure 10 is a cross-sectional view of the fastening member 110 before crimping. Figure 11 is a cross-sectional view of the fastening member 110 after crimping. The shaft portion 112 is the part that extends in the Z direction and is inserted into the through holes 40A and 50A. The shaft portion 112 has screw threads formed on it that screw into the nut 116, and the nut 116 has screw grooves formed on it for fixing the shaft portion 112. The shaft portion 112 is fixed to the nut 116 by fastening the screw threads into the screw grooves. The head portion 113 provides a seating surface that is pressed against and in close contact with the busbar bottom surface 50B, which is one of the main surfaces of the second busbars 50P and 50N.

[0093] The enlarged diameter portion 114 is formed between the head portion 113 and the shaft portion 112, and is disc-shaped with a larger diameter than the shaft portion 112. However, the diameter of the enlarged diameter portion 114 is smaller than that of the head portion 113. The crimping portions 115 are shaped to protrude radially from the outer circumferential surface of the enlarged diameter portion 114, and multiple crimping portions are arranged at equal intervals around the circumferential direction of the enlarged diameter portion 114.

[0094] For example, as shown in Figure 10, when the bolt 111 is being inserted into the through hole 50A, that is, when the seating surface of the head 113 has not yet reached the bottom surface 50B of the busbar, the crimping portion 115 is not deformed. When the bolt 111 is pushed into the through hole 50A from the state shown in Figure 10 to the state shown in Figure 11, the crimping portion 115 is crushed radially between itself and the inner wall surface of the through hole 50A. In other words, the crimping portion 115 undergoes plastic deformation in the radial direction of the through hole 50A and is crimped to the second busbars 50P and 50N. As a result, the bolt 111 is positioned so that it cannot move radially relative to the second busbars 50P and 50N.

[0095] In this embodiment, even in the state shown in Figure 11 after crimping is complete, the bolt bottom surface 113A, which is one surface of the head 113, is located closer to the base 162 than the busbar bottom surface 50B, and the vertical positions of the bolt bottom surface 113A and the busbar bottom surface 50B do not coincide. In other words, a part of the bolt side surface 113B, which is the side surface of the head 113, protrudes from the busbar bottom surface 50B towards the base 162. Thus, a step is formed at the boundary between the second busbars 50P, 50N and the fastening member 110 due to the protrusion of the bolt side surface 113B. The heat dissipation member 169 deforms to follow the shape of the step and is in close contact with the step.

[0096] In the first region 181, the head portion 113 and the first extension portion 501P are in close contact with the heat dissipation member 269. Through the heat dissipation member 269 and the base 162, the heat from the first fastening portion 60A and the fastening member 110 is dissipated to the base 21. In the second region 182, the head portion 113 and one end of the N-side second busbar 50N are in close contact with the heat dissipation member 369. Through the heat dissipation member 369 and the base 162, the heat from the second fastening portion 60B and the fastening member 110 is dissipated to the base 21.

[0097] <Chips and Ribs> When screwing the nut 116 onto the shaft portion 112, the nut 116 may rub against the main surface of the first busbars 40P and 40N. The first busbars 40P and 40N, and the second busbars 50P and 50N are made of copper or aluminum. The bolt 111 and nut 116 are made of iron or stainless steel. The first busbars 40P and 40N, and the second busbars 50P and 50N are made of a softer material than the fastening member 110. In other words, the fastening member 110 is harder than the first busbars 40P and 40N, and the second busbars 50P and 50N. Therefore, when the nut 116 rubs against the main surface of the first busbars 40P and 40N during assembly, the first busbars 40P and 40N may be worn down.

[0098] Figure 12 is a cross-sectional view illustrating the chips 100. When the first busbars 40P and 40N are machined, metal chips called chips 100 are generated. Since the chips 100 are part of conductive components such as busbars, they are sometimes referred to as conductive pieces. The shape of the chips 100 can be long and continuous chips called flow chips 100, or short, powdery chips called shear chips 100. When flow chips 100 straddle two adjacent conductive parts, an unintended conductive path is formed between the two conductive parts.

[0099] In this embodiment, if chips 100 are generated at the first fastening portion 60A or the second fastening portion 60B, the chips 100 may straddle the space between the two. If both ends of the chips 100 come into contact with both, there is a risk of a short circuit occurring between the first fastening portion 60A and the second fastening portion 60B. In this embodiment, a first extension portion 163A is provided between the first fastening portion 60A and the second fastening portion 60B. This prevents the chips 100 from straddling the space between the two. Consequently, a short circuit between the first fastening portion 60A and the second fastening portion 60B is prevented.

[0100] Hereinafter, the contact surface with the nut 116 on the first busbars 40P and 40N may be referred to as the contact surface 40B. The contact surface 40B may also be referred to as the nut contact surface. The length of the first extension 163A in the Z direction is longer than the distance from the surface 162A to the contact surface 40B. The tip of the first extension 163A is positioned further from the surface 162A than the contact surface 40B. The length of the first extension 163A in the Z direction is approximately equal to the distance from the surface 162A to the upper end of the nut 116. The length of the second extension 163B in the Z direction is equal to the length of the first extension 163A in the Z direction. The length of the rib 163 in the Z direction is uniform. As an example, the lengths of the first flange 164, the second flange 165, and the third flange 166 in the Z direction are equal to the length of the rib 163.

[0101] <Measures to prevent leakage of heat dissipation members> The first busbars 40P and 40N, and the second busbars 50P and 50N are pressed against the heat dissipation member 169 by the nut 116 or by their own weight. On the P side, the P-side first busbar 40P and the P-side second busbar 50P are pressed against the heat dissipation member 269. In this case, the heat dissipation member 269 may overflow from the first recess 168A.

[0102] However, in this embodiment, in the planar direction, the P-side busbars 40P and 50P and the heat dissipation member 269 are provided between the rib 163 and the first flange 164. In other words, the heat dissipation member 269 is sandwiched between the rib 163 and the first flange 164 in the planar direction. This prevents the heat dissipation member 269 from leaking out of the base 162 beyond the rib 163 and the first flange 164.

[0103] With respect to the N side, the N-side busbars 40N and 50N are pressed against the heat dissipation member 369. In this case, the heat dissipation member 369 may overflow from the second recess 168B. With respect to the planar direction, the heat dissipation member 369 is provided between the rib 163 and the second flange 165. In other words, the heat dissipation member 369 is sandwiched between the rib 163 and the second flange 165. This prevents the heat dissipation member 369 from leaking out of the base 162 beyond the rib 163 and the second flange 165. In this embodiment, leakage of the heat dissipation members 269 and 369 can be suppressed, so the amount of heat dissipation members 269 and 369 can be kept to the minimum necessary.

[0104] <Effects> The power converter 4 includes first busbars 40P and 40N, second busbars 50P and 50N, a fastening member 110, an insulating member 161, and a heat dissipation member 169. The P-side first busbar 40P and the P-side second busbar 50P are fastened together via the fastening member 110. The N-side first busbar 40N and the N-side second busbar 50N are fastened together via the fastening member 110. The insulating member 161 has a base 162 that overlaps the first fastening portion 60A and the second fastening portion 60B, and ribs 163 that rise from the base 162. The heat dissipation member 169 has insulating properties. The heat dissipation member 169 is provided on the base 162 and dissipates heat from the first fastening portion 60A and the second fastening portion 60B to the base 162. A rib 163 is provided between the first fastening portion 60A and the second fastening portion 60B.

[0105] When fastening the fastening member 110 to the first busbars 40P, 40N and the second busbars 50P, 50N, the fastening member 110 may rub against the main surface of the first busbars 40P, 40N, causing the first busbars 40P, 40N to be worn down. When the busbars are worn down, conductive pieces, which are long, continuous metal chips called chips 100, may be generated. In this embodiment, a first extension 163A, which is part of the rib 163, is provided between the first fastening portion 60A and the second fastening portion 60B. The presence of the first extension 163A prevents the chips 100 from bridging between the first fastening portion 60A and the second fastening portion 60B. This prevents the first fastening portion 60A and the second fastening portion 60B from short-circuiting via the chips 100.

[0106] Furthermore, even if the metal shavings 100 fall and one end comes into contact with the heat dissipation member 169 on the first fastening portion 60A side, and the other end comes into contact with the second fastening portion 60B, the heat dissipation member 169 has insulating properties, which prevents a short circuit between the two.

[0107] In this embodiment, the tip of the first extension 163A is positioned further away from the base 162 than the contact surface 40B. This prevents the chips 100 from bridging the gap between the first fastening portion 60A and the second fastening portion 60B. Furthermore, even if the chips 100 fall, it prevents them from being positioned so that one end contacts the heat dissipation member 169 on the first fastening portion 60A side and the other end contacts the second fastening portion 60B.

[0108] A first recess 168A is provided in the base 162 so as to overlap the first fastening portion 60A. A heat dissipation member 269 is provided in the first recess 168A. The heat dissipation member 269 has an overlapping portion 269A that overlaps with the first fastening portion 60A in the Z direction, and non-overlapping portions 269B and 269C that do not overlap with the first fastening portion 60A in the Z direction. The non-overlapping portions 269B and 269C are exposed to the outside air.

[0109] Similarly, a second recess 168B is provided in the base 162 so as to overlap the second fastening portion 60B. A heat dissipation member 369 is provided in the second recess 168B. The heat dissipation member 369 has an overlapping portion 369A that overlaps with the second fastening portion 60B in the Z direction, and non-overlapping portions 369B, 369C, and 369D that do not overlap with the second fastening portion 60B in the Z direction. The non-overlapping portions 369B, 369C, and 369D are exposed to the outside air.

[0110] The recess 168A restricts the movement of the heat dissipation member 269. The second recess 168B restricts the movement of the heat dissipation member 369. This prevents the thickness of the heat dissipation members 269 and 369 from becoming thinner. It also prevents a decrease in the heat dissipation performance of the fastening portions 60A and 60B. Furthermore, by providing the non-overlapping portions 269B, 269C, 369B, 369C, and 369D described above, it is made easier for one end of the fallen metal shavings 100 to come into contact with the insulating heat dissipation members 269 and 369. This prevents short circuits from occurring between adjacent fastening portions 60A and 60B via the metal shavings 100.

[0111] The arrangement of the fastening portions 60A, 60B, the non-overlapping portions 269B, 369B, 369D, and the rib 163 is as follows: A non-overlapping portion 269B is provided between the first fastening portion 60A and the first extension portion 163A. A non-overlapping portion 369B is provided between the second fastening portion 60B and the first extension portion 163A. A non-overlapping portion 369D is provided between the second fastening portion 60B and the second extension portion 163B. When chips 100 fall, the non-overlapping portions 269B, 369B, 369D are provided adjacent to the fastening portions 60A, 60B, making it easy for the chips 100 to fall into the non-overlapping portions 269B, 369B, 369D. Because one end of the fallen metal shavings 100 is likely to come into contact with the insulating heat dissipation members 269 and 369, it is possible to suppress short circuits between the metal shavings 100 and the adjacent fastening parts 60A and 60B.

[0112] Furthermore, the heat dissipation member 169 has sufficient viscosity to hold the chips 100 before hardening. This makes it easier to capture the fallen chips 100 and prevents short circuits from occurring between adjacent fastening parts 60A and 60B via the chips 100.

[0113] The first busbar 40P on the P side and the first busbar 40N on the N side extend along the X direction. The second busbar 50P on the P side has a first extension 501P extending in the X direction, a second extension 502P extending in the Y direction, and a third extension 503P extending in the X direction. The second busbar 50N on the N side extends in the Y direction. The rib 163 has a first extension 163A extending in the X direction and a second extension 163B extending in the Y direction.

[0114] The first fastening portion 60A and the second fastening portion 60B are aligned in the Y direction. A first extension portion 163A is provided between the first fastening portion 60A and the second fastening portion 60B. A second extension portion 163B is provided between the second extension portion 502P and the N-side second busbar 50N. This configuration makes it possible to suppress both short circuits caused by metal shavings 100 between the fastening portions 60A and 60B and short circuits caused by metal shavings 100 between the fastening portion 60B and the adjacent second extension portion 502P.

[0115] <Second Embodiment> Other embodiments are described below. The other embodiments will be described focusing on the differences from the first embodiment. Hereafter, in the other embodiments as well, the focus will be on the differences from the embodiments described earlier. Configurations, operations, and effects that are not specifically described in the other embodiments are the same as in the embodiments described earlier.

[0116] In the first embodiment, a configuration was described in which the base 162 is provided with a first recess 168A and a second recess 168B. However, the base 162 does not necessarily have to be provided with the first recess 168A and the second recess 168B. Figure 13 is a cross-sectional view of the second embodiment. In the second embodiment, heat dissipation members 269 and 369 are provided on the surface 162A of the base 162. The heat dissipation members 269 and 369 are provided along the surface 162A. The P-side second busbar 50P and fastening member 110 are arranged to contact the heat dissipation member 269. The N-side second busbar 50N and fastening member 110 are arranged to contact the heat dissipation member 369. In this configuration as well, the same effects as in the first embodiment are achieved.

[0117] <Third Embodiment> In the first embodiment, a configuration in which the fastening member 110 has a bolt 111 and a nut 116 was described. However, the fastening member 110 does not have to have a nut 116. Figure 14 is a cross-sectional view of the third embodiment. In the third embodiment, the fastening member 110 has a bolt 111. The shaft portion 112 of the bolt 111 is inserted into the through holes 40A and 50A from the first busbar 40P and 40N side, and its tip and end are fastened to the heat dissipation member 169. The heat dissipation member 169 may include a gap filler as well as a resin member for fastening the shaft portion 112. In the third embodiment as well, a screw thread is formed on the shaft portion 112 and a screw groove is formed on the resin member, and the shaft portion 112 and the resin member are fixed together by fastening the two.

[0118] In the third embodiment, the second busbars 50P and 50N, the first busbars 40P and 40N, and the head 113 are stacked in that order from the base 162 side. The first busbars 40P and 40N and the head 113 are in contact with each other in the Z direction. The contact surfaces of the first busbars 40P and 40N with the head 113 are sometimes referred to as the contact surface 40C. The contact surface 40C is sometimes referred to as the head contact surface. The length of the first extension 163A in the Z direction is longer than the distance from the surface 162A to the contact surface 40C. The tip of the first extension 163A is positioned further from the surface 162A than the contact surface 40C. This configuration also produces the same effects as the first embodiment.

[0119] <Fourth Embodiment> In the first embodiment, the first fastening cooler 160 was described, but the structure of the first fastening cooler 160 may also be applied to the second fastening cooler 260. Figure 15 is a plan view of the fastening portion of the fourth embodiment. Figure 16 is a cross-sectional view along the line XVI-XVI in Figure 15. As described above, in the first housing space 26, the main terminals 32P, 32N and the capacitor busbars 71P, 71N are connected via the fastening member 110. An insulating member 261 is provided at the two fastening portions between the main terminals 32P, 32N and the capacitor busbars 71P, 71N, such that the base 262 overlaps it below.

[0120] The main terminals 32P, 32N and the capacitor busbars 71P, 71N generate heat when energized. In particular, the fastening areas have high thermal resistance and generate a large amount of heat. The second fastening cooler 260 has an insulating member 261 and a heat dissipation member 169. The insulating member 261 has a base 262, ribs 263, flanges 264, 265, and recesses 268A, 268B. The ribs 263 and flanges 264, 265 are connected to the base 262. The base 262 has plate thickness in the Z direction. The base 262 has a surface 262A facing the main terminals 32P, 32N and the capacitor busbars 71P, 71N, and a back surface 262B facing the base 21. The base 262 is roughly rectangular in plan view.

[0121] The base 262 has a first edge 272A facing the first wall 23A, a second edge 272B facing the second wall 23B, a third edge 272C facing the third wall 23C, and a fourth edge 272D facing the fourth wall 23D. A flange 264 is provided on the first edge 272A. A flange 265 is provided on the third edge 272C. The rib 263 and the flanges 264 and 265 extend in the Z direction so as to rise from the surface 262A.

[0122] Hereinafter, the fastening portion between the main terminal 32P and the capacitor busbar 71P may be referred to as the P-side fastening portion 60C. At the P-side fastening portion 60C, one end of the main terminal 32P and the capacitor busbar 71P are stacked in the Z direction, and the two are fastened together by the fastening member 110. Similarly, the fastening portion between the main terminal 32N and the capacitor busbar 71N may be referred to as the N-side fastening portion 60D. At the N-side fastening portion 60D, one end of the main terminal 32N and the capacitor busbar 71N are stacked in the Z direction, and the two are fastened together by the fastening member 110. The main terminals 32P and 32N, and the capacitor busbars 71P and 71N are made of a material softer than the fastening member 110.

[0123] The base 262 overlaps the P-side fastening portion 60C and the N-side fastening portion 60D in the Z direction. A recess 268A is provided at the position overlapping the P-side fastening portion 60C, recessing from the surface 262A toward the back surface 262B. A recess 268B is provided at the position overlapping the N-side fastening portion 60D, recessing from the surface 262A toward the back surface 262B. Heat dissipation members 169 are provided in recesses 268A and 268B, respectively. The heat dissipation member 169 provided in recess 268A may be referred to as heat dissipation member 469, and the heat dissipation member 169 provided in recess 268B may be referred to as heat dissipation member 569.

[0124] Through holes 71A are formed in the capacitor busbars 71P and 71N, and through holes 32A are formed in the main terminals 32P and 32N. One end of the capacitor busbars 71P and 71N and the main terminals 32P and 32N are stacked in the Z direction so that the through holes 71A and 32A are in communication. In this embodiment, the capacitor busbars 71P and 71N are positioned closer to the base 262 than the main terminals 32P and 32N. The bolts 111 are inserted from the side of the capacitor busbars 71P and 71N. The bolts 111 are inserted into the through holes 71A and 32A. By tightening the inserted bolts 111 in the Z direction with nuts 116, the capacitor busbars 71P and 71N and the main terminals 32P and 32N are fastened to each other.

[0125] Starting from the base 262 side, the components are stacked in the following order: head 113, capacitor busbars 71P and 71N, main terminals 32P and 32N, and nut 116. The head 113 of the bolt 111 is in contact with the capacitor busbars 71P and 71N. The nut 116 is in contact with the main terminals 32P and 32N.

[0126] According to this, one end of the P-side capacitor busbar 71P and the fastening member 110 are in close contact with the heat dissipation member 469. The heat dissipation member 469 dissipates heat from the P-side fastening portion 60C and the fastening member 110 to the base 262. One end of the N-side capacitor busbar 71N and the fastening member 110 are in close contact with the heat dissipation member 569. The heat dissipation member 569 dissipates heat from the N-side fastening portion 60D and the fastening member 110 to the base 262.

[0127] Furthermore, a rib 263 is provided between the P-side fastening portion 60C and the N-side fastening portion 60D. The contact surface with the nut 116 at the main terminals 32P and 32N is sometimes referred to as the contact surface 32B. The length of the rib 263 in the Z direction is longer than the distance from the surface 262A to the contact surface 32B. The tip of the rib 263 is positioned further from the surface 262A than from the contact surface 32B.

[0128] The presence of the rib 263 prevents the chips 100 from bridging the gap between the P-side fastening portion 60C and the N-side fastening portion 60D. This prevents a short circuit between the P-side fastening portion 60C and the N-side fastening portion 60D via the chips 100. Furthermore, even if the chips 100 fall and one end contacts the heat dissipation member 469, and the other end crosses the rib 263 and contacts the N-side fastening portion 60D, a short circuit between the P-side fastening portion 60C and the N-side fastening portion 60D can still be prevented. In addition, the presence of flanges 264 and 265 prevents leakage from the base 262 even if the heat dissipation members 469 and 569 overflow from the recesses 268A and 268B.

[0129] (Other Embodiments) In the first to fourth embodiments, the insulating members 161 and 261 were described in which two fastening portions 60A and 60B overlap with the bases 162 and 262. However, the insulating members may overlap with multiple fastening portions. As an example, the power converter 4 has three fastening portions between the internal busbar 91 and the main terminal 32O. The insulating members may be provided so that the three fastening portions of the internal busbar 91 and the main terminal 32O overlap with the base. Ribs may be provided between two adjacent fastening portions. The number of fastening portions is not limited to two or three. Depending on the product, the insulating members may be provided so that multiple fastening portions overlap with the base.

[0130] Furthermore, the fastening member 110 is not limited to those including a bolt 111. For example, the fastening member 110 may be a rivet or a pin. This is because even with rivets or pins, conductive fragments may be generated due to friction when they are inserted into the busbar. Also, the fastening member 110 may include welding. For example, in spot welding, two metal plates are joined by sandwiching them between electrodes and applying pressure while passing a large current for a short time. In this process, if the force of the electrodes sandwiching the metal plates is excessive, it is conceivable that chipping of the metal plates may occur, generating conductive fragments.

[0131] This disclosure is described in accordance with the embodiments, but it is understood that this disclosure is not limited to such embodiments or structures. This disclosure also includes various modifications and variations within the scope of equivalents. In addition, while various combinations and forms are shown in this disclosure, other combinations and forms that include one, more, or fewer of those elements also fall within the scope and concept of this disclosure.

[0132] (Disclosure of Technical Ideas) This specification discloses several technical ideas as described in the following paragraphs. Some paragraphs may be written in a multiple dependent form, where subsequent paragraphs optionally refer to preceding paragraphs. Furthermore, some paragraphs may be written in a multiple dependent form, where they refer to other multiple dependent forms. These paragraphs written in multiple dependent forms define several technical ideas.

[0133] (Technical Concept 1) A conductive member (40P, 50P, 40N, 50N, 32P, 71P, 32N, 71N) including a first conductive piece (40P, 40N, 32P, 32N) that forms an electrical path, and a second conductive piece (50P, 50N, 71P, 71N) that forms the electrical path together with the first conductive piece; a fastening member (110) that fastens the first conductive piece and the second conductive piece together; an insulating member (161, 261) including a base (162, 262) that overlaps the fastening portions (60A, 60B, 60C, 60D) of the first conductive piece and the second conductive piece, and vertical walls (163, 263) rising from the base; and an insulating heat dissipation member (169) provided on the base that dissipates heat from the fastening portions to the base. An electrical device having a plurality of the conductive members and the fastening members, wherein at least two of the fastening portions overlap the heat dissipation member, and the vertical wall is provided between two adjacent fastening portions.

[0134] (Technical Concept 2) The fastening member comprises a bolt (111) including a head (113) and a shaft (112), and a nut (116) on which the shaft is fixed, the first conductive piece and the second conductive piece are stacked and each has through holes (40A, 50A, 32A, 71A) through which the shaft passes, the fastening portion is stacked in the order of the head, the conductive piece, and the nut from the base side, and with respect to the stacking direction (Z) in which the first conductive piece and the second conductive piece are stacked, the tip of the vertical wall is provided further away from the base than the nut contact surface (40B) on the conductive piece that contacts the nut. This is the electrical device according to Technical Concept 1.

[0135] (Technical Idea 3) The fastening member has a bolt (111) including a head (113) and a shaft (112), the first conductive piece and the second conductive piece are stacked and each has through holes (40A, 50A, 32A, 71A) through which the shaft passes, the fastening portion is stacked in the order of the conductive member and the head from the base side, and with respect to the stacking direction (Z) in which the first conductive piece and the second conductive piece are stacked, the tip of the vertical wall is provided further away from the base than the head contact surface (40C) that contacts the head of the conductive member, as described in Technical Idea 1.

[0136] (Technical Idea 4) The base has recesses (168A, 168B) in which the heat dissipation member is provided at positions where the fastening portions overlap with respect to the stacking direction, a part of the heat dissipation member overlaps with the fastening portions in the stacking direction, the remainder of the heat dissipation member does not overlap with the fastening portions in the stacking direction, and the non-overlapping portions (269B, 269C, 369B, 369C, 369D) of the heat dissipation member that do not overlap with the fastening portions are exposed to the outside air, as described in technical idea 2 or 3.

[0137] (Technical idea 5) The electrical device according to technical idea 4, wherein the non-overlapping portion is provided between the fastening portion and the vertical wall.

[0138] (Technical Idea 6) The electrical device according to Technical Idea 5, wherein the first conductive piece extends in a first direction (X) different from the stacking direction, the second conductive piece extends in a second direction (Y) different from the stacking direction and the first direction, the vertical wall has a first extension (163A) extending in the first direction and a second extension (163B) extending in the second direction, a plurality of fastening portions are arranged in the second direction, the first extension is provided between two adjacent fastening portions, and the second extension is provided between one fastening portion and another adjacent fastening portion connected to the second conductive piece.

[0139] (Technical Concept 7) The electrical device according to Technical Concept 6, wherein the insulating member further comprises a first opposing portion (164A) rising from the base so as to face the first extension, and a second opposing portion (164B) rising from the base so as to face the second extension, the first conductive piece being provided between the first opposing portion and the first extension, and the second conductive piece being provided between the second opposing portion and the second extension.

[0140] (Technical Idea 8) The electrical device according to any one of Technical Ideas 1 to 7, wherein the conductive member is made of a material softer than the fastening member.

[0141] (Technical Idea 9) The electrical device according to any one of Technical Ideas 1 to 8, wherein the heat dissipation member is a member that has viscosity to the extent that it can hold conductive pieces generated from the conductive member before or after curing.

Claims

1. A conductive member (40P, 50P, 40N, 50N, 32P, 71P, 32N, 32P, 71N) including a first conductive piece (40P, 40N, 32P, 32N) that forms an electrical path, and a second conductive piece (50P, 50N, 71P, 71N) that forms the electrical path together with the first conductive piece; a fastening member (110) that fastens the first conductive piece and the second conductive piece together; an insulating member (161, 261) including a base (162, 262) that overlaps the fastening portions (60A, 60B, 60C, 60D) of the first conductive piece and the second conductive piece, and vertical walls (163, 263) rising from the base; an insulating heat dissipation member (169) provided on the base that dissipates heat from the fastening portions to the base; wherein there are multiple conductive members and fastening members. An electrical device in which at least two of the fastening portions overlap the heat dissipation member, and the vertical wall is provided between two adjacent fastening portions.

2. The fastening member comprises a bolt (111) including a head (113) and a shaft (112), and a nut (116) to which the shaft is fixed, the first conductive piece and the second conductive piece are stacked and each has through holes (40A, 50A, 32A, 71A) through which the shaft passes, the fastening portion is stacked in the order of the head, the conductive piece, and the nut from the base side, and with respect to the stacking direction (Z) in which the first conductive piece and the second conductive piece are stacked, the tip of the vertical wall is provided further away from the base than the nut contact surface (40B) of the conductive piece that contacts the nut. The electrical device according to claim 1.

3. The fastening member has a bolt (111) including a head (113) and a shaft (112), the first conductive piece and the second conductive piece are stacked and each has a through hole (40A, 50A, 32A, 71A) through which the shaft passes, the fastening portion is stacked in the order of the conductive member and the head from the base side, and with respect to the stacking direction (Z) in which the first conductive piece and the second conductive piece are stacked, the tip of the vertical wall is provided further away from the base than the head contact surface (40C) that contacts the head of the conductive member, as described in claim 1.

4. The electrical device according to claim 2 or 3, wherein the base has recesses (168A, 168B) in which the heat dissipation member is provided at positions where the fastening portions overlap with respect to the stacking direction, a portion of the heat dissipation member overlaps with the fastening portions in the stacking direction, the remainder of the heat dissipation member does not overlap with the fastening portions in the stacking direction, and the non-overlapping portions (269B, 269C, 369B, 369C, 369D) of the heat dissipation member that do not overlap with the fastening portions are exposed to the outside air.

5. The electrical device according to claim 4, wherein the non-overlapping portion is provided between the fastening portion and the vertical wall.

6. The electrical device according to claim 5, wherein the first conductive piece extends in a first direction (X) different from the stacking direction, the second conductive piece extends in a second direction (Y) different from the stacking direction and the first direction, the vertical wall has a first extension (163A) extending in the first direction and a second extension (163B) extending in the second direction, a plurality of fastening portions are arranged in the second direction, the first extension is provided between two adjacent fastening portions, and the second extension is provided between one fastening portion and another adjacent fastening portion connected to the second conductive piece.

7. The electrical device according to claim 6, wherein the insulating member further comprises a first opposing portion (164A) rising from the base so as to face the first extension, and a second opposing portion (164B) rising from the base so as to face the second extension, the first conductive piece being provided between the first opposing portion and the first extension, and the second conductive piece being provided between the second opposing portion and the second extension.

8. The electrical device according to claim 2 or 3, wherein the conductive member is made of a material softer than the fastening member.

9. The electrical device according to claim 8, wherein the heat dissipation member is a member that has viscosity to the extent that it can hold conductive pieces generated from the conductive member before or after curing.

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