Circuit unit

Abstract

To provide a circuit unit capable of improving heat dissipation performance by suppressing gap variation caused by the tolerance between thermal contact portions of heat-generating components accommodated in a case and a heat dissipation target.SOLUTION: A circuit unit 10 includes a heat-generating component 22 having a thermal contact portion 14 in thermal contact with a heat dissipation target 12, and a fixing portion 16 to be fixed to the heat dissipation target 12, a case 24 for holding the heat-generating component 22, a holding portion (26) that protrudes to the interior of the case 24 and holds the heat-generating component 22 in the case 24, an opening window 28 that extends through the case 24 and exposes the thermal contact portion 14 of the heat-generating component 22 to the exterior of the case 24, and an insertion hole 30 that is provided to extend through the case 24 and into which a fixed portion 42 provided on the heat dissipation target 12 is inserted. By fixing the fixing portion 16 of the heat-generating component 22 to the fixed portion 42 inserted into the insertion hole 30, the heat-generating component 22 is separated from the fixing portion 26, and the thermal contact portion 14 of the heat-generating component 22 is brought into thermal contact with the heat dissipation target 12.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present disclosure relates to a circuit unit.

Background Art

[0002] Patent Document 1 discloses a circuit unit that is housed in a battery pack mounted on a vehicle and switches between energization and non-energization between a battery and a load. The circuit unit houses heat-generating components such as a relay and a precharge resistor that is a ceramic resistor in a case. In order to promote heat dissipation of such heat-generating components, in the circuit unit of Patent Document 1, the heat contact portion of the heat-generating component fixed to the case is brought into contact with a metal outer casing that is a heat dissipation target via an elastic heat conduction sheet, thereby adopting a structure that secures a heat dissipation path for the heat-generating component.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the structure of Patent Document 1, due to the accumulation of tolerances in the assembly of the inner case and the heat-generating component and the assembly of the inner case and the outer casing, it was inevitable that the variation in the distance between the opposing surfaces of the heat-generating component and the outer casing increased. As a result, when the tolerance becomes large, the required thickness of the elastic heat conduction sheet interposed between the heat-generating component and the outer casing increases, which may lead to a decrease in heat dissipation performance.

[0005] Therefore, a circuit unit is disclosed that can suppress the gap variation due to the tolerance between the heat contact portion of the heat-generating component housed in the case and the heat dissipation target, thereby improving the heat dissipation performance.

Means for Solving the Problems

[0006] The circuit unit of the present disclosure includes a heat-generating component having a thermally contacting portion that thermally contacts a heat dissipation target and a fixing portion that is fixed to the heat dissipation target, a case that holds the heat-generating component, a holding portion that protrudes inside the case and holds the heat-generating component within the case, an opening window that penetrates the case and exposes the thermally contacting portion of the heat-generating component to the outside of the case, and an insertion hole that penetrates the case and into which a fixed portion provided on the heat dissipation target is inserted. By fixing the fixing portion of the heat-generating component to the fixed portion inserted into the insertion hole, the heat-generating component is separated from the holding portion, and the thermally contacting portion of the heat-generating component is thermally contacted with the heat dissipation target.

Advantages of the Invention

[0007] According to the circuit unit of the present disclosure, it is possible to suppress the gap variation due to the tolerance between the thermally contacting portion of the heat-generating component housed in the case and the heat dissipation target, and improve the heat dissipation performance.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Embodiments for Carrying Out the Invention

[0009] <Description of Embodiments of the Present Disclosure> First, embodiments of the present disclosure will be listed and described. The circuit unit of the present disclosure is (1) A heat-generating component having a thermally contacting portion that thermally contacts a heat-dissipating target and a fixing portion fixed to the heat-dissipating target, a case that holds the heat-generating component, a holding portion that protrudes inside the case and holds the heat-generating component in the case, an opening window that penetrates the case and exposes the thermally contacting portion of the heat-generating component to the outside of the case, and an insertion hole that penetrates the case and into which a fixed portion provided on the heat-dissipating target is inserted. By fixing the fixing portion of the heat-generating component to the fixed portion inserted into the insertion hole, the heat-generating component is separated from the holding portion, and the thermally contacting portion of the heat-generating component is thermally contacted with the heat-dissipating target.

[0010] According to the circuit unit of this aspect, by directly fixing the fixing portion of the heat-generating component held in the case to the fixed portion of the heat-dissipating target inserted into the case through the insertion hole provided in the case, the heat-generating component can be separated from the holding portion of the case, and the thermally contacting portion of the heat-generating component can be thermally contacted with the heat-dissipating target. Thereby, the members intervening between the heat-generating component and the heat-dissipating target can be eliminated, and compared with the conventional structure, the variation in the distance between the thermally contacting portion of the heat-generating component and the opposing surface of the heat-dissipating target due to tolerances can be reduced. Furthermore, by fixing the fixing portion of the heat-generating component to the fixed portion of the heat-dissipating target, the thermally contacting portion of the heat-generating component exposed to the outside of the case through the opening window of the case can be thermally contacted with the heat-dissipating target, and the contact state of the thermally contacting portion of the heat-generating component with the heat-dissipating target can be stably maintained. Therefore, it is possible to suppress the gap variation due to the tolerance between the thermally contacting portion of the heat-generating component accommodated in the case and the heat-dissipating target and improve the heat dissipation performance.

[0011] (2) In the above (1), it is preferable that, in a state where the heat-generating component is fixed to the heat-dissipating target, the thermally contacting portion of the heat-generating component is in contact with the heat-dissipating target via an elastic heat-conducting member. By interposing an elastic heat-conducting member between the thermally contacting portion of the heat-generating component and the heat-dissipating target, it is possible to absorb the variation due to the tolerance of the gap between the opposing surfaces of the two, prevent the generation of a gap between the opposing surfaces, and further improve the heat dissipation performance.

[0012] (3) In the above (1) or (2), it is preferable that the holding part includes a frame part that surrounds the periphery of the opening window and protrudes inward of the case, and a held part protruding from the peripheral wall part of the heat generating component is placed on the protruding end face of the frame part. Since the holding part includes a frame part that surrounds the periphery of the opening window and protrudes inward of the case, the frame part can prevent interference between the heat generating component and other members. Further, since the held part protruding from the peripheral wall part of the heat generating component is placed on the protruding end face of the frame part, it is possible to reliably prevent the heat generating component from protruding from the opening window. Thereby, the heat generating component in the transportation state etc. of the circuit unit before being fixed to the fixed part to be cooled can be stably held in the case.

[0013] (4) In the above (3), it is preferable that the holding part further includes a bending piece part that protrudes more inward of the case than the frame part and is elastically deformable on the outer peripheral side of the opening window. The bending piece part has a locking claw part provided at the protruding tip and protruding to the inner peripheral side of the opening window. By the bending piece part being elastically deformed to the outer peripheral side, the assembly of the heat generating component to the frame part is allowed. In a state where the held part of the heat generating component is placed on the protruding end face of the frame part, the locking claw part of the elastically restored bending piece part overlaps with the heat generating component with a gap in the protruding direction of the frame part. The holding part further includes a bending piece part combined with the frame part, and the locking claw part provided at the protruding tip of the bending piece part overlaps with the heat generating component having the held part placed on the protruding end face of the frame part with a gap in the protruding direction of the frame part. Thereby, not only the protrusion of the heat generating component from the opening window but also the displacement in the opposite direction can be restricted by the engagement with the locking claw part, and the heat generating component can be held more stably in the case.

[0014] (5) In the above (3) or (4), the fixing portion of the heat generating component is provided at the same position as the held portion in the protruding direction of the frame portion, and in a state where it is fixed to the object to be cooled, the fixed portion of the object to be cooled is arranged inside the case beyond the protruding end face in the protruding direction of the frame portion. This is preferable. In the protruding direction of the frame portion, the fixing portion of the heat generating component is provided at the same position as the held portion on which it is placed on the protruding end face of the frame portion, and the fixed portion of the object to be cooled is arranged inside the case beyond the protruding end face. Thereby, by fixing the fixing portion to the fixed portion, the heat generating component can be separated from the holding portion (frame portion), and the fixing portion of the heat generating component can be directly fixed to the fixed portion of the object to be cooled. As a result, it is possible to advantageously avoid or suppress a reduction in heat dissipation performance due to the overlap of tolerances.

[0015] (6) In any one of the above (1) to (5), the case includes a lower case provided with the opening window and an upper case superposed on the lower case. The opening window has a rectangular shape. The holding portion includes protruding wall portions respectively provided on a pair of opposite sides of the opening window and protruding inward of the case, a positioning wall portion provided on one of the other pair of opposite sides of the opening window and protruding inward of the case, and a displacement restricting rib provided on the upper case and arranged opposite to the positioning wall portion with the heat generating component interposed therebetween. The heat generating component is arranged and positioned between the opposing surfaces of the positioning wall portion and the displacement restricting rib and between the opposing surfaces of the protruding wall portions. It is preferable that a held portion protruding from the peripheral wall portion of the heat generating component arranged between the protruding wall portions is placed on the protruding end face of the protruding wall portion.

[0016] The heat-generating component can be easily placed at a predetermined position by inserting it between the protruding wall portions so as to slide and move from the side opposite to the positioning wall portion toward the positioning wall portion with respect to the lower case and abutting against the positioning wall portion. Further, by assembling the upper case, the heat-generating component can be placed and positioned between the opposing surfaces of the positioning wall portion and the displacement restricting rib and between the opposing surfaces of the protruding wall portions. In addition, since the held portion protruding from the peripheral wall portion of the heat-generating component disposed between the protruding wall portions is placed on the protruding end surface of the protruding wall portion, it is possible to reliably prevent the heat-generating component from protruding from the opening window. As a result, the heat-generating component in the transport state or the like of the circuit unit before being fixed to the fixed portion to be cooled can be stably held in the case.

[0017] (7) In the above (6), it is preferable that the holding portion includes a displacement restricting piece that extends from the protruding tip of the positioning wall portion toward the heat-generating component side, is disposed inside the case more than the protruding end surface of the protruding wall portion, and is disposed opposite to the heat-generating component with a gap therebetween. A displacement restricting piece is provided at the protruding tip of the positioning wall portion, which is disposed inside the case more than the protruding end surface of the protruding wall portion and is disposed opposite to the heat-generating component with a gap therebetween. Thereby, not only the protrusion of the heat-generating component from the opening window but also the displacement in the opposite direction can be restricted by the engagement with the displacement restricting piece, and the heat-generating component can be held more stably in the case.

[0018] (8) In the above (6) or (7), the fixing part of the heat generating component is provided at the same position as the held part in the protruding direction of the protruding wall part, and in a state where it is fixed to the heat dissipation target, the fixed part of the heat dissipation target is arranged inside the case beyond the protruding end face in the protruding direction of the protruding wall part. This is preferable. In the protruding direction of the protruding wall part, the fixing part of the heat generating component is provided at the same position as the held part on which the fixing part of the heat generating component is placed on the protruding end face of the protruding wall part, and the fixed part of the heat dissipation target is arranged inside the case beyond the protruding end face. Thereby, by fixing the fixing part to the fixed part, the heat generating component can be separated from the holding part (protruding wall part), and the fixing part of the heat generating component can be directly fixed to the fixed part of the heat dissipation target. As a result, it is possible to advantageously avoid or suppress a reduction in heat dissipation performance due to the overlap of tolerances.

[0019] <Details of Embodiments of the Present Disclosure> A specific example of the circuit unit of the present disclosure will be described below with reference to the drawings. Note that the present disclosure is not limited to these examples, and is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0020] <Embodiment 1> Hereinafter, the circuit unit 10 of Embodiment 1 of the present disclosure will be described with reference to FIGS. 1 to 9. This circuit unit 10 is mounted on, for example, an electric vehicle or a hybrid vehicle and is connected between an in-vehicle power supply (for example, a battery) not shown and a load (for example, an inverter) not shown. Note that the circuit unit 10 can be arranged in an arbitrary orientation in the vehicle. Hereinafter, the upper direction refers to the upper direction in FIG. 4, the lower direction refers to the lower direction in FIG. 4, the left direction refers to the left direction in FIG. 3, the right direction refers to the right direction in FIG. 3, the front direction refers to the lower direction in FIG. 3, and the rear direction refers to the upper direction in FIG. 3. Also, for a plurality of identical members, only some members may be labeled with reference numerals, and other members may be omitted.

[0021] <Circuit Unit 10> The circuit unit 10 includes a heat-generating component having a thermally contacting portion 14 that thermally contacts a heat dissipation target (the housing 12 described later) and a fixing portion 16 that is fixed to the heat dissipation target (the housing 12). Note that the circuit unit 10 of Embodiment 1 includes a relay 18, a precharge relay 20, and a precharge resistor 22 as electrical components that generate heat when energized. However, in Embodiment 1, since the structure of the present disclosure is applied to the precharge resistor 22 among the above electrical components, the heat-generating component is constituted by the precharge resistor 22. Further, the circuit unit 10 includes a case 24 that holds the heat-generating component (the precharge resistor 22). In Embodiment 1, not only the precharge resistor 22 but also the relay 18 and the precharge relay 20 are housed and held within the case 24.

[0022] Furthermore, the circuit unit 10 includes a holding portion 26 that protrudes inside the case 24 and holds the heat-generating component (the precharge resistor 22) within the case 24, an opening window 28 that is provided to penetrate the case 24 and exposes the thermally contacting portion 14 of the heat-generating component (the precharge resistor 22) to the outside of the case 24, and an insertion hole 30 that is provided to penetrate the case 24 and into which a fixing portion 42 (described later) provided on the heat dissipation target (the housing 12) is inserted.

[0023] <Heat dissipation target (housing 12)> The circuit unit 10 and the battery that constitutes the in-vehicle power supply can be accommodated, for example, in a metal housing 12. The circuit unit 10 and the battery are accommodated in the housing 12 to form a battery pack (not shown). That is, the circuit unit 10 is overlapped and fixed on the upper surface 32 of the housing 12, and heat generated when energizing the electrical components provided in the circuit unit 10 is dissipated through the housing 12. Therefore, in Embodiment 1, the heat dissipation target for the heat generated in the circuit unit 10 is constituted by the metal housing 12. In the figure, a flat metal plate constituting the bottom wall portion of the housing 12 is shown. As shown in FIG. 1, for example, a refrigerant flow path 34 can be formed inside this metal plate. A known refrigerant is adopted for the refrigerant flowing through the refrigerant flow path 34. Also, the extending direction, length, etc. of the refrigerant flow path 34 shown in FIG. 1 are merely examples, and the extending direction, length, etc. of the refrigerant flow path are not limited.

[0024] Furthermore, as also shown in FIG. 6, on the upper surface 32 of the housing 12, support portions 36 that support the four corners of the circuit unit 10 project upward at four locations around the fixed position of the circuit unit 10. In the center of each support portion 36, a bolt fastening hole 40 for fastening a bolt 38 for fixing the circuit unit 10 is formed to open upward. Furthermore, on the upper surface 32 of the housing 12, at a predetermined location at the fixed position of the circuit unit 10, a fixed portion 42 for fixing the heat generating component (pre-charge resistor 22) projects upward. In Embodiment 1, two fixed portions 42, 42 are provided at a predetermined distance in the front-rear direction, and each fixed portion 42 has a predetermined protruding dimension. In particular, in Embodiment 1, each fixed portion 42 is generally prismatic as a whole, and at the upper end portion of each fixed portion 42, a screw fastening hole 46 for fastening a screw 44 for fixing each fixed portion 16 and each fixed portion 42 is formed.

[0025] <Relay 18> In Embodiment 1, in circuit unit 10, a pair of relays 18, 18 are provided and are arranged to be spaced apart from each other in the left - right direction. One of the relays (the right - hand side in Embodiment 1) is the positive - electrode - side relay 18a, and the other (the left - hand side in Embodiment 1) is the negative - electrode - side relay 18b. These positive - electrode - side and negative - electrode - side relays 18a, 18b each have a pair of terminal portions 48, 48 (one is shown in FIG. 4) that are spaced apart from each other in the left - right direction on the front side (the positive - electrode - side relay 18a is in the front, and the negative - electrode - side relay 18b is in the rear), and each terminal portion 48 is exposed on the surface of each relay 18a, 18b.

[0026] Each terminal portion 48 is a terminal portion for input and output with respect to each relay 18a, 18b. For example, in the positive - electrode - side relay 18a, the left - hand terminal portion 48 is the input - side terminal portion on the positive - electrode side, and the right - hand terminal portion 48 is the output - side terminal portion on the positive - electrode side. Also, in the negative - electrode - side relay 18b, the left - hand terminal portion 48 is the output - side terminal portion on the negative - electrode side, and the right - hand terminal portion 48 is the input - side terminal portion on the negative - electrode side.

[0027] A bus bar 50 for energization is overlapped on each terminal portion 48 of each of these relays 18a, 18b and is fixed by a bolt 52. That is, the circuit unit 10 includes first and second bus bars 50a, 50b for energization connected to the input - side and output - side terminal portions 48, 48 of the positive - electrode - side relay 18a, and third and fourth bus bars 50c, 50d for energization connected to the input - side and output - side terminal portions 48, 48 of the negative - electrode - side relay 18b. In a state where the circuit unit 10 is assembled, the end portions of the first to fourth bus bars 50a to 50d are exposed to the outside through through - holes 106a to 106d provided in an upper case 98 (described later) of the case 24, and input - side and output - side connection portions 54a, 54b on the positive - electrode side and input - side and output - side connection portions 54c, 54d on the negative - electrode side are respectively formed.

[0028] Then, the input connection part 54a on the positive electrode side and the input connection part 54c on the negative electrode side are electrically connected to the positive electrode side and negative electrode side terminal parts of a battery (not shown) respectively by a conductive member made of a bus bar, an electric wire, or the like. Also, the output connection part 54b on the positive electrode side and the output connection part 54d on the negative electrode side are electrically connected to the positive electrode side and negative electrode side terminal parts of an inverter (not shown) respectively by a conductive member. Each of these connection parts 54a to 54d and the conductive member can be fixed by a bolt 56 respectively.

[0029] Thereby, including each relay 18a, 18b, the first to fourth power supply bus bars 50a to 50d, and the above-mentioned respective conductive members, a main circuit 58 between the battery and the inverter is configured. And in this main circuit 58, by switching the ON and OFF states of each relay 18a, 18b, the energized state and non-energized state in the main circuit 58 can be switched between the battery and the inverter.

[0030] Also, in addition to the first to fourth power supply bus bars 50a to 50d, first to fourth heat dissipation bus bars 60a to 60d are fastened together with each bolt 52 to each terminal part 48 in the positive electrode side and negative electrode side relays 18a, 18b respectively. The first to fourth heat dissipation bus bars 60a to 60d are each substantially L-shaped, and have a portion extending in the vertical direction and a portion that bends from the lower end of the portion extending in the vertical direction and spreads in the horizontal direction (a direction perpendicular to the vertical direction). Each of the heat dissipation bus bars 60a to 60d is fixed to each terminal part 48 in each relay 18a, 18b by each bolt 52 at their upper end portions, and their lower end portions extend in the front-rear direction and are located below each relay 18a, 18b.

[0031] At the lower ends of these heat-dissipating bus bars 60a to 60d, a heat-dissipating portion 62 is formed by a portion extending in the front-rear direction. Each heat-dissipating portion 62 is in thermal contact with the housing 12 to be heat-dissipated via an insulating sheet 64 and an elastic heat-conducting member 66. Known materials can be adopted as the insulating sheet 64 and the elastic heat-conducting member 66. In particular, as the elastic heat-conducting member 66, for example, a heat-conducting sheet or a gap filler having good thermal conductivity can be adopted. With such a structure, each terminal portion 48 of each relay 18a, 18b is in thermal contact with the housing 12 via each heat-dissipating bus bar 60a to 60d, the insulating sheet 64, and the elastic heat-conducting member 66, and the heat generated with the energization of each relay 18a, 18b can be dissipated from the housing 12.

[0032] <Precharge circuit 68> A precharge circuit 68 is connected in parallel to the positive-side relay 18a in the main circuit 58. Specifically, in the precharge circuit 68, a precharge relay 20 and a precharge resistor 22 are connected in series. And the precharge relay 20 and the input terminal portion 48 of the positive-side relay 18a are electrically connected by an electric wire 70, and the precharge resistor 22 and the output terminal portion 48 of the positive-side relay 18a are electrically connected by an electric wire 72. Also, the precharge relay 20 and the precharge resistor 22 are electrically connected by an electric wire 74.

[0033] Terminals 76 are provided at at least one end of each of the electric wires 70, 72, 74, and each terminal 76 is overlapped with each terminal portion 48 of the positive-side relay 18a or each terminal portion 80 (to be described later) of the precharge relay 20 and fixed by a bolt 52 or a screw 78.

[0034] <Precharge relay 20> As the precharge relay 20, a known one can be adopted, and its structure is not limited, but it includes a pair of terminal portions 80, 80 (one is shown in FIG. 4) that are spaced apart from each other in the left - right direction. In Embodiment 1, the precharge relay 20 is arranged with its upper side facing the front, and each terminal portion 80 is exposed on the upper surface of the precharge relay 20. Then, a terminal 76 provided at the end of an electric wire 70 connecting the positive - side relay 18a and the precharge relay 20 is overlapped with the input - side terminal portion 80 (the left - hand terminal portion 80) of the precharge relay 20 and fixed by a screw 78. Also, a terminal 76 provided at the end of an electric wire 74 connecting the precharge relay 20 and the precharge resistor 22 is overlapped with the output - side terminal portion 80 (the right - hand terminal portion 80) of the precharge relay 20 and fixed by a screw 78.

[0035] <Precharge resistor 22> The precharge resistor 22 is configured using a metal - clad resistor. Since a known one can be adopted as the precharge resistor 22 (metal - clad resistor), detailed description is omitted. However, a winding resistor (not shown) is encapsulated in a metal case 82 in an insulated state. In sectional views such as FIG. 5, the illustration of the internal structure of the precharge resistor 22 is omitted, and only the metal case 82 is shown. In other words, the metal case 82 of the precharge resistor 22 has a hollow shape, and a winding resistor (not shown) is accommodated in the metal case 82 in an insulated state. In Embodiment 1, the metal case 82 of the precharge resistor 22 has a hollow substantially rectangular - parallelepiped shape and is arranged in a direction extending in the front - rear direction. That is, the metal case 82 includes a substantially cylindrical peripheral wall portion 84 formed by including wall portions on both sides in the front - rear direction and both sides in the left - right direction, an upper wall portion 86 covering the upper opening of the peripheral wall portion 84, and a lower wall portion 88 covering the lower opening of the peripheral wall portion 84.

[0036] In particular, in Embodiment 1, at the upper end portion (or the upper wall portion 86) of the peripheral wall portion 84 in the metal case 82, flange-like portions 90 protruding on both sides in the front-rear direction are provided. Each of these flange-like portions 90 has a width direction (left-right direction) dimension substantially equal to that of the upper wall portion 86 (or the peripheral wall portion 84) and a predetermined protruding dimension (front-rear direction dimension). In the central portion in the left-right direction of each flange-like portion 90, a screw insertion groove 92 through which the aforementioned screw 44 for fixing the precharge resistor 22 is inserted is provided. By providing each of these flange-like portions 90, in the vertical projection, the upper surface (the upper surface of the upper wall portion 86) 93a of the precharge resistor 22 has a larger area than the lower surface (the lower surface of the lower wall portion 88) 93b of the precharge resistor 22.

[0037] As will be described later, each flange-like portion 90 is overlapped with each fixed portion 42 in the housing 12, and each screw 44 is inserted into the screw insertion groove 92 and fastened to the screw fastening hole 46, so that the fixed portion 16 in the heat generating component (precharge resistor 22) is fixed to the fixed portion 42. Therefore, the fixed portion 16 is constituted by the portion around the screw insertion groove 92 (the central portion in the left-right direction in each flange-like portion 90) in each flange-like portion 90. Further, by placing both end portions in the left-right direction of each flange-like portion 90 on the holding portion 26 protruding inside the case 24 (the lower case 100 described later), the heat generating component (precharge resistor 22) is held inside the case 24. Therefore, the held portion 94 is constituted by both end portions in the left-right direction of each flange-like portion 90. As a result, in Embodiment 1, each fixed portion 16 and each held portion 94 are both provided in each flange-like portion 90, that is, they are provided at the same position in the vertical direction.

[0038] As described above, the precharge resistor 22 is connected to the electric wire 72 connected to the positive-side relay 18a and the electric wire 74 connected to the precharge relay 20. Specifically, the electric wire 72 is connected to one end of the winding provided inside the precharge resistor 22, and the electric wire 74 is connected to the other end. And each electric wire 72, 74 connected to both ends of the winding extends from the inside to the outside of the metal case 82. In Embodiment 1, each electric wire 72, 74 extends from one end in the length direction of the metal case 82 (the front end in Embodiment 1) to the outside. And each terminal 76 provided at the end of each of these electric wires 72, 74 is overlapped with the output terminal portion 48 in the positive-side relay 18a and the output terminal portion 80 in the precharge relay 20, respectively, and is fixed by bolts 52 and screws 78, respectively.

[0039] The metal case 82 of this precharge resistor 22 (metal-clad resistor) has a thermal contact portion 14 that thermally contacts the housing 12 as a heat dissipation target. In Embodiment 1, in the state where the metal case 82 is fixed to the housing 12 in the circuit unit 10 described later, the metal case 82 is overlapped with the housing 12 via the elastic heat conduction member 96 provided so as to overlap the lower surface 93b, and the lower wall portion 88 constituting the hollow metal case 82 constitutes the thermal contact portion 14. As this elastic heat conduction member 96, a member of the same material as the elastic heat conduction member 66 provided below each of the relays 18a, 18b can be adopted. Note that each of these elastic heat conduction members 66, 96 may be in the form of a rectangular sheet in its initial shape, or the initial shape may be in the form of a gel or grease and hardened into a sheet shape by applying heat and light.

[0040] <Case 24> As described above, the circuit unit 10 has the respective relays 18a and 18b, the precharge relay 20, and the case 24 that holds the precharge resistor 22. In Embodiment 1, the case 24 is a hollow rectangular parallelepiped as a whole, and the lateral dimension is larger than the longitudinal dimension. In particular, in Embodiment 1, the case 24 includes an upper case 98 and a lower case 100 that can be assembled and disassembled with each other in the vertical direction. These upper case 98 and lower case 100 are formed of, for example, synthetic resin. The fixing method of the upper case 98 and the lower case 100 is not limited, but in Embodiment 1, with the upper case 98 and the lower case 100 being overlapped, the bolts 38 described above are inserted at the four corners of the circuit unit 10 and fastened to the bolt fastening holes 40 provided in the respective support portions 36 of the housing 12, so that the upper case 98 and the lower case 100 are fixed to each other.

[0041] The upper case 98 has a substantially box shape that opens downward as a whole, and includes an upper bottom wall portion 102 and an upper peripheral wall portion 104 that protrudes downward from the outer peripheral edge portion of the upper bottom wall portion 102. In the upper bottom wall portion 102, rectangular through windows 106a to 106d that penetrate in the thickness direction (vertical direction) are provided at positions corresponding to the respective connection portions 54a to 54d of the first to fourth power supply bus bars 50a to 50d in a state where the circuit unit 10 is assembled. Mounting portions 110 having bolt insertion holes 108 are provided at the four corners around the upper case 98, and each mounting portion 110 is located somewhat above the lower end of the upper peripheral wall portion 104. Further, in the upper bottom wall portion 102, circular insertion holes 112 that penetrate in the thickness direction are provided at positions corresponding to the respective insertion holes 30 of the lower case 100 in a state where the circuit unit 10 is assembled, and the respective screws 44 are fastened to the bolt fastening holes 40 in the respective fixed portions 42 from above through the respective insertion holes 112.

[0042] As shown in FIG. 7 and the like, the lower case 100 has a bottom wall portion 114 that is flat as a whole, and the bottom wall portion 114 has substantially the same rectangular shape as the upper case 98 in plan view. Thus, when the upper case 98 and the lower case 100 are overlapped and fixed, the lower opening of the upper case 98 is covered by the bottom wall portion 114 of the lower case 100.

[0043] In the bottom wall portion 114, rectangular opening windows 116 that penetrate in the thickness direction (vertical direction) are provided at positions corresponding to the heat dissipation portions 62 of the first to fourth heat dissipation bus bars 60a to 60d in the state where the circuit unit 10 is assembled. Further, in the bottom wall portion 114, at a position corresponding to the heat contact portion 14 (the lower wall portion 88 of the metal case 82) of the pre-charge resistor 22 (metal clad resistor) in the state where the circuit unit 10 is assembled, the above-described opening window 28 that penetrates in the thickness direction (vertical direction) is provided. In Embodiment 1, the opening window 28 has a rectangular shape and has an area larger than the lower surface 93b of the pre-charge resistor 22 in plan view. Thus, the opening window 28 exposes the heat contact portion 14 (the lower wall portion 88) of the metal case 82 so as to be thermally contactable with the housing 12 in the state where the circuit unit 10 is assembled. Further, on both sides in the front-rear direction of the opening window 28, the above-described insertion holes 30 into which the fixed portions 42 of the housing 12 are inserted are formed. These insertion holes 30 have a substantially rectangular shape. In Embodiment 1, the opening window 28 and the insertion holes 30 communicate with each other, and the insertion holes 30 are formed by connecting on both sides in the front-rear direction of the inner peripheral surface of the opening window 28.

[0044] In Embodiment 1, an insulating sheet 64 and an elastic heat conductive member 66 are accommodated in a laminated state in each opening window 116 provided below each heat radiating portion 62. Thereby, each heat radiating portion 62 in the first to fourth heat radiating bus bars 60a to 60d is in contact with the housing 12 that is superposed on the bottom wall portion 114 in an electrically insulated state and in a thermally conductive state. Note that the insulating sheet 64 and the elastic heat conductive member 66 do not necessarily need to be separate members, and may be constituted by one member having insulating properties and heat conductivity. These insulating sheet 64 and elastic heat conductive member 66 are fixed (for example, adhered) to the lower surface of each heat radiating portion 62 when, for example, the circuit unit 10 is fixed to the housing 12. As shown in FIG. 4, when the circuit unit 10 is fixed to the housing 12, each insulating sheet 64 and each elastic heat conductive member 66 are arranged in an accommodated state inside each opening window 116.

[0045] Further, an elastic heat conductive member 96 is accommodated in an opening window 28 provided below a thermal contact portion 14 in the precharge resistor 22. Thereby, the thermal contact portion 14 is in contact with the housing 12 in a thermally conductive state. Since the wire resistor constituting the precharge resistor 22 is accommodated in the metal case 82 in an insulated state, even when the circuit unit 10 is in an energized state, the metal case 82 is in an electrically insulated state, and the insulating sheet 64 does not have to be arranged in the opening window 28. This elastic heat conductive member 96 is fixed (for example, adhered) to the lower surface 93b of the thermal contact portion 14 (the lower wall portion 88 of the metal case 82) when, for example, the circuit unit 10 is fixed to the housing 12. When the circuit unit 10 is fixed to the housing 12, the elastic heat conductive member 96 is arranged in an accommodated state inside the opening window 28.

[0046] Furthermore, at the four corners around the lower case 100 (bottom wall portion 114), there are provided mounting portions 120 having bolt insertion holes 118, and each mounting portion 120 is positioned somewhat above other portions in the bottom wall portion 114. In other words, at the four corners around the lower surface 121 of the lower case 100, recessed portions that are concave upward with respect to other portions are formed. In this way, on the outer peripheral portions of the upper case 98 and the lower case 100, by forming the respective mounting portions 110 and 120 at the four corners around, a concave-convex shape corresponding to each other is provided. As a result, when the upper case 98 and the lower case 100 are overlapped in the vertical direction, by fitting these concave-convex shapes, the upper case 98 and the lower case 100 can be positioned relative to each other in the horizontal direction.

[0047] <Holding portion 26> Furthermore, the lower case 100 includes the aforementioned holding portion 26, and this holding portion 26 includes a frame body portion 122 that surrounds the periphery of the opening window 28 and protrudes upward inside the case 24. That is, the protruding direction of the frame body portion 122 is in the vertical direction (specifically, the direction from the bottom to the top). Specifically, the frame body portion 122 has a pair of side wall portions 124, 124 that extend in the front-rear direction at both left-right direction side edges of the opening window 28, and each of these side wall portions 124 has a front-rear direction dimension larger than that of the opening window 28. And both front and rear end portions of each side wall portion 124 are bent in a crank shape, and both front and rear end portions of each side wall portion 124 are positioned inward in the left-right direction from the middle portion in the front-rear direction via the bent portions 126. Both front and rear end portions of each of these side wall portions 124 are mounting portions 128 on which respective flange-like portions 90 in the metal case 82 of the pre-charge resistor 22 are placed.

[0048] Each placement portion 128 is located outward in the front-rear direction from the opening window 28. In Embodiment 1, since the insertion holes 30 are formed connecting to both front and rear ends of the opening window 28 in the front-rear direction, each placement portion 128 is provided on both left and right sides of each insertion hole 30. In other words, at both front and rear ends of the frame body portion 122 in the front-rear direction, an insertion window portion 129 penetrating in the front-rear direction is provided between the opposing sides of each placement portion 128, and the inside and outside of the frame body portion 122 are interconnected by each insertion window portion 129. In Embodiment 1, two electric wires 72, 74 extend from the front end portion of the pre-charge resistor 22, and when the pre-charge resistor 22 is held by the frame body portion 122 (holding portion 26), each electric wire 72, 74 extends outward through the front insertion window portion 129. However, depending on the wiring pattern of the pre-charge circuit 68, each electric wire 72, 74 may extend outward through the rear insertion window portion 129.

[0049] More specifically, at both front and rear ends of the protruding end face (upper end face) 130 of the frame body portion 122, that is, with respect to the protruding end face 130 of each placement portion 128, each flange-shaped portion 90 (particularly, the held portions 94 which are both left and right end portions) in the metal case 82 is configured to be placed.

[0050] Here, the upward protruding dimension A (see FIG. 9) of the frame body portion 122 (the vertical dimension from the upper surface of the bottom wall portion 114 to the protruding end face 130) is made smaller than the upward protruding dimension B (see FIG. 5) of each fixed portion 42 provided on the housing 12 (the vertical dimension from the upper surface 32 of the housing 12 to the upper surface of each fixed portion 42). Particularly, as will be described later, in a state where the circuit unit 10 is fixed to the housing 12, each fixed portion 42 protrudes into the inside of the circuit unit 10 through each insertion hole 30 of the lower case 100, and each fixed portion 42 is arranged inward (upward) of the case 24 beyond the protruding end face 130 in the protruding direction (vertical direction) of the frame body portion 122. In short, in a state where the circuit unit 10 is fixed to the housing 12, the upper surface of each fixed portion 42 is positioned above the protruding end face 130 of the frame body portion 122.

[0051] <Flexing piece portion 132> In addition, the holding portion 26 protrudes upward inside the case 24 rather than the frame portion 122, and includes a bending piece portion 132 that can be elastically deformed (elastically deformed in Embodiment 1) on the outer peripheral side of the opening window 28. In Embodiment 1, the bending piece portions 132 are provided at the intermediate portions in the front-rear direction of each side wall portion 124. In particular, in Embodiment 1, a pair of bending piece portions 132, 132 are provided so as to be separated from each other in the front-rear direction at the intermediate portions in the front-rear direction of each side wall portion 124. Therefore, in Embodiment 1, a total of four bending piece portions 132 are provided in the holding portion 26.

[0052] Each bending piece portion 132 has a locking claw portion 134 provided at the protruding tip (upper end portion) and protruding inward in the left-right direction on the inner peripheral side (inner side in the left-right direction) of the opening window 28. Each locking claw portion 134 protrudes inward in the left-right direction to a position that overlaps the upper wall portion 86 of the pre-charge resistor 22 (metal case 82) in the up-down direction in a state where the pre-charge resistor 22 is assembled to the lower case 100. In other words, in the projection in plan view in a state where the pre-charge resistor 22 is assembled to the lower case 100, the protruding tips (inner ends in the left-right direction) of each locking claw portion 134 and the left and right side edge portions of the upper wall portion 86 overlap.

[0053] And on the upper surface of each locking claw portion 134, an inclined surface 136 that gradually inclines downward as it goes inward in the left-right direction is provided. As a result, when the pre-charge resistor 22 is assembled to the holding portion 26, the pre-charge resistor 22 is brought close to the holding portion 26 from above, so that the left and right side edge portions of the lower surface 93b of the metal case 82 come into contact with the inclined surfaces 136 of each locking claw portion 134, and each bending piece portion 132 is elastically deformed outward in the left-right direction. Thereby, the assembly of the pre-charge resistor 22 to the frame portion 122 is allowed. Further, in a state where each flange-shaped portion 90 of the metal case 82 is placed on the protruding end surface 130 of each mounting portion 128, each bending piece portion 132 is elastically restored and deformed (elastic return), so that, as shown in FIG. 9 and the like, the locking claw portions 134 of each bending piece portion 132 overlap the pre-charge resistor 22 with a gap 138 therebetween in the protruding direction (up-down direction) of the frame portion 122.

[0054] <Assembly of Circuit Unit 10> Hereinafter, a specific example of the assembling method of the circuit unit 10 will be described. Note that the assembling method of the circuit unit 10 is not limited to the embodiments described below.

[0055] First, the first to fourth power supply busbars 50a to 50d and the first to fourth heat dissipation busbars 60a to 60d are respectively superposed on each terminal portion 48 of each relay 18a, 18b, and each is fixed by each bolt 52. At this time, each terminal 76 provided at the end of each electric wire 70, 72 is also superposed on each terminal portion 48 of the positive electrode side relay 18a, and each is clamped together by a bolt 52. Then, these relays 18a, 18b and the precharge relay 20 are placed on the lower case 100 and fixed by bolts or screws.

[0056] Also, the precharge resistor 22 is brought close to the holding portion 26 in the lower case 100 from above, and is assembled while elastically deforming each bending piece portion 132 outward in the left - right direction. When the locking claw portion 134 in each bending piece portion 132 gets over the upper wall portion 86 in the metal case 82, each bending piece portion 132 elastically restores and deforms. As a result, each flange - like portion 90 in the metal case 82 is placed on the protruding end surface 130 of each mounting portion 128 in the holding portion 26, and each held portion 94 at both left - right ends of each flange - like portion 90 is held by the holding portion 26. In this state, the inner ends in the left - right direction of each locking claw portion 134 overlap the left - right side edge portions of the upper wall portion 86 in the vertical direction. For example, even when the precharge resistor 22 is displaced upward, the engagement of each locking claw portion 134 and the upper wall portion 86 prevents the precharge resistor 22 from coming out upward from the holding portion 26. In other words, in this state, the precharge resistor 22 is displaceable in the vertical direction within each gap 138 and is temporarily assembled to the lower case 100.

[0057] Subsequently, with respect to the lower case 100 with each relay 18a, 18b, the precharge relay 20 and the precharge resistor 22 assembled as described above, the upper case 98 is brought close from above as shown in FIG. 8, and the upper case 98 and the lower case 100 are superposed as shown in FIG. 9. As a result, each mounting portion 110 in the upper case 98 and each mounting portion 120 in the lower case 100 are superposed, and as described above, the concavo-convex shapes of the outer peripheral portions of the upper case 98 and the lower case 100 are fitted. As a result, the horizontal displacement between the upper case 98 and the lower case 100 is prevented, and the circuit unit 10 of Embodiment 1 is completed. In the circuit unit 10 before being assembled to the housing 12, for example, by inserting bolts 38 into the bolt insertion holes 108, 118 at the four corners of the periphery, the upper case 98 and the lower case 100 may not be separated in the vertical direction.

[0058] <Assembly of the circuit unit 10 to the heat dissipation target (housing 12)> Hereinafter, a specific example of a method for assembling the circuit unit 10 to the housing 12, which is a heat dissipation target, will be described. Note that the method for assembling the circuit unit 10 to the housing 12 is not limited to the mode described below.

[0059] First, the circuit unit 10 manufactured as described above is overlapped on a predetermined position on the upper surface 32 of the housing 12. In FIGS. 2 and 3, for clarity, the upper case 98 is shown in a state separated from the lower case 100, but the circuit unit 10 is assembled to the housing 12 integrally. At that time, each insulating sheet 64 and each elastic heat conducting member 66 are laminated and fixed to each heat radiating portion 62 of each heat radiating bus bar 60a to 60d, and the elastic heat conducting member 96 is fixed to the lower wall portion 88 of the precharge resistor 22 (metal case 82). Further, the circuit unit 10 is overlapped on the upper surface 32 such that each support portion 36 protruding on the upper surface 32 fits into a recess formed due to the provision of the mounting portion 120 on the lower surface of the circuit unit 10 (the lower surface 121 of the lower case 100). Thereby, the circuit unit 10 and the housing 12 are positioned in the horizontal direction, and each bolt insertion hole 108, 118 at the four corners of the circuit unit 10 and the bolt fastening hole 40 in each support portion 36 are communicated in the vertical direction.

[0060] Then, by overlapping the circuit unit 10 on the upper surface 32 of the housing 12, each fixed portion 42 protruding upward from the upper surface 32 is inserted into the circuit unit 10 through each insertion hole 30 provided in the lower case 100. In particular, as described above, in a state where the lower surface of the circuit unit 10 (the lower surface 121 of the lower case 100) and the upper surface 32 of the housing 12 are overlapped, the upper surface of each fixed portion 42 protrudes upward beyond the protruding end surface 130 of each frame portion 122. Thereby, in a state where the lower surface 121 of the circuit unit 10 and the upper surface 32 of the housing 12 are overlapped, the upper surface of each fixed portion 42 abuts against each flange-shaped portion 90 of each metal case 82 from below, and these flange-shaped portions 90 (in particular, each held portion 94) are separated upward from the protruding end surface 130 of the holding portion 26 (in particular, the mounting portion 128). As a result, the screw insertion groove 92 in each flange-shaped portion 90 and the screw fastening hole 46 in each fixed portion 42 are communicated in the vertical direction.

[0061] From such a state, bolts 38 are inserted into the bolt insertion holes 108 and 118 at the four corners of the circuit unit 10 and fastened to the respective bolt fastening holes 40. Also, screws 44 are inserted through the respective screw insertion grooves 92 through the respective insertion holes 112 in the upper case 98 and fastened to the respective screw fastening holes 46, and the respective fixing portions 16 constituted by the portions around the respective screw insertion grooves 92 and the respective fixed portions 42 are fixed. Thereby, the assembly of the circuit unit 10 to the housing 12 is completed. In a state where the circuit unit 10 is assembled to the housing 12, the heat radiating portions 62 in the respective heat radiating bus bars 60a to 60d are in thermal contact with the housing 12 via the respective insulating sheets 64 and the respective elastic heat conductive members 66, and the heat contact portion 14 in the precharge resistor 22 is in thermal contact with the housing 12 via the elastic heat conductive member 96. In a state where the circuit unit 10 is assembled to the housing 12, it is preferable that these respective insulating sheets 64 and the respective elastic heat conductive members 66 and 96 are slightly compressed in the vertical direction between the respective heat radiating portions 62 and the heat contact portion 14 (lower wall portion 88) and the housing 12.

[0062] As described above, in the circuit unit 10 assembled in the housing 12 of the battery pack, the respective connection portions 54a to 54d are electrically connected to the battery and the inverter by a conductive member (not shown). Thereby, the battery and the inverter are electrically connected via the circuit unit 10.

[0063] Here, generally, when the vehicle is started, electricity flows from the battery to the inverter to charge the capacitor in the inverter. However, the current (inrush current) at the time of such vehicle startup is relatively large, and if the inrush current flows through the main circuit, there is a risk of damaging the main relay. A precharge resistor is provided for the purpose of preventing this damage. That is, at the time of vehicle startup, the positive-side relay 18a is turned OFF and the precharge relay 20 is turned ON, so that power is supplied from the battery to the capacitor in the inverter via the precharge circuit 68, thereby avoiding damage to the positive-side relay 18a and charging the capacitor. After the vehicle is started, the positive-side relay 18a is turned ON and the precharge relay 20 is turned OFF, so that power is supplied from the battery to the inverter through the main circuit 58. Therefore, when the precharge circuit 68 is energized at the time of vehicle startup, the precharge resistor 22 generates heat, and when the main circuit 58 is energized after the vehicle is started, the relays 18a and 18b generate heat. That is, the timing of heat generation of the precharge resistor 22 and the positive-side relay 18a is different.

[0064] On the other hand, the housing 12 with which the thermal contact portion 14 is in thermal contact is also in thermal contact with the positive-side relay 18a. Thereby, in the precharge resistor 22 and the positive-side relay 18a with different heat generation timings, a common heat dissipation path can be configured, and an increase in the number of parts, etc., is avoided compared to the case where the precharge resistor 22 and the positive-side relay 18a form separate heat dissipation paths.

[0065] In the circuit unit 10 of Embodiment 1 having the above-described structure, a metal clad resistor capable of handling a large current is employed as the precharge resistor 22. That is, in the metal clad resistor, a wire resistor in an insulating state is housed in a metal case 82, and heat dissipation through the metal case 82 is possible. Thereby, the metal clad resistor is superior in heat dissipation property to, for example, a ceramic resistor, and even when a plurality of ceramic resistors are required, the metal clad resistor can handle a large current with a smaller number (for example, one). As a result, the mounting space of the precharge resistor can be reduced, and the circuit unit 10 can be miniaturized.

[0066] In particular, in the circuit unit 10, before being attached to the housing 12 which is the heat dissipation target, the precharge resistor 22 which is a heat generating component is held by a holding portion 26 provided in the case 24 within the case 24. However, when attaching to the housing 12, the precharge resistor 22 is separated from the holding portion 26, and each fixing portion 16 in the precharge resistor 22 is directly fixed to each fixed portion 42 in the housing 12. Thereby, it is not necessary to consider the tolerance in the case 24, and the heat conducting contact portion 14 in the precharge resistor 22 and the housing 12 can be more reliably brought into thermal contact.

[0067] Specifically, an elastic heat conducting member 96 is provided between the heat conducting contact portion 14 and the housing 12. Thereby, an air layer does not intervene between the heat conducting contact portion 14 and the housing 12, and improvement in heat dissipation efficiency is achieved. And when, for example, in the conventional structure, the precharge resistor is fixed to the case and the case is fixed to the housing to bring the precharge resistor and the housing into thermal contact, it is necessary to consider the tolerance in the case, and accordingly, it is necessary to make the elastic heat conducting member thick. In other words, by directly fixing the precharge resistor 22 and the housing 12 as in Embodiment 1, it is not necessary to consider the tolerance in the case 24, and accordingly, the elastic heat conducting member 96 can be made thin, and improvement in heat conduction efficiency can be achieved.

[0068] The holding portion 26 includes a frame portion 122 that surrounds the periphery of the opening window 28 and protrudes inwardly of the case 24. Before the circuit unit 10 is fixed to the housing 12, the held portion 94 (flange-like portion 90) that protrudes outward from the peripheral wall portion 84 of the pre-charge resistor 22 is placed on the protruding end face 130 of the frame portion 122. Thereby, in the circuit unit 10, extraction of the pre-charge resistor 22 through the opening window 28 can be prevented. In particular, in Embodiment 1, the frame portion 122 includes a pair of side wall portions 124, 124 that face each other in the left-right direction. In a state where the pre-charge resistor 22 is held by the holding portion 26, displacement of the pre-charge resistor 22 in the left-right direction is also suppressed. As a result, before the circuit unit 10 is fixed to the housing 12, displacement of the pre-charge resistor 22 in the case 24 is suppressed, and damage to the pre-charge resistor 22 and the like can be prevented.

[0069] Furthermore, the holding portion 26 includes a flexible piece portion 132 having a locking claw portion 134 at the protruding tip. In a state where the pre-charge resistor 22 is assembled to the holding portion 26, by the respective locking claw portions 134 coming into contact with the upper wall portion 86 of the metal case 82, upward extraction of the pre-charge resistor 22 from the holding portion 26 is prevented. Therefore, before the circuit unit 10 is fixed to the housing 12, not only is displacement in the left-right direction suppressed as described above, but also upward displacement is suppressed, so that damage to the pre-charge resistor 22 and the like can be more reliably prevented.

[0070] Each fixing portion 16 of the precharge resistor 22 is provided at the same position in the vertical direction as each held portion 94, and the fixed portion 42 in the housing 12 is arranged higher beyond the protruding end face 130 of the frame portion 122 when the circuit unit 10 is fixed to the housing 12. In the first embodiment, each fixing portion 16 and each held portion 94 of the precharge resistor 22 are both formed in each flange-shaped portion 90 of the metal case 82. For example, compared with the case where the fixing portion and the held portion are provided separately, the precharge resistor 22, and thus the circuit unit 10, can be manufactured with a simpler structure. Further, each fixed portion 42 protrudes upward from the upper surface 32 of the housing 12, and a screw fastening hole 46 is provided at the upper end portion of each fixed portion 42. Thereby, in the housing 12, the refrigerant flow path 34 can be formed without considering the positions of the screw fastening holes 46.

[0071] <Second Embodiment> Next, the circuit unit 140 of the second embodiment of the present disclosure will be described with reference to FIGS. 10 to 16. The basic structure of the circuit unit 140 in the second embodiment is the same as that in the first embodiment, and the configurations of the main circuit 58 and the precharge circuit 68 are the same as those in the first embodiment. On the other hand, in the circuit unit 140 of the second embodiment, the manner in which the precharge resistor 22 is held by the holding portion 142 in the state before being fixed to the housing 12 is different from that in the first embodiment. Hereinafter, mainly the differences from the first embodiment will be described, and for the same members and parts as those in the first embodiment, the same reference numerals as those in the first embodiment are given in the drawings, and detailed descriptions thereof are omitted.

[0072] <Case 144> Also in the circuit unit 140 of the second embodiment, it has each relay 18a, 18b, the precharge relay 20, and a case 144 that holds the precharge resistor 22, and this case 144 is configured to include an upper case 146 and a lower case 148. The upper case 146 and the lower case 148 are overlapped and fixed to each other.

[0073] <Upper Case 146> The upper case 146 has the same shape as the upper case 98 in Embodiment 1 as a whole. However, in the upper case 146 of Embodiment 2, a displacement restricting rib 150 is provided which is disposed opposite to a positioning wall portion 156 (described later) provided on the lower case 148 with a heat generating component (pre-charge resistor 22) interposed therebetween. Specifically, a displacement restricting rib 150 is provided protruding downward from the upper bottom wall portion 102 to the right of each insertion hole 112 at the right end portion of the upper case 146. In Embodiment 2, the displacement restricting rib 150 is integrally formed with the upper case 146 in a substantially rectangular plate shape, has a predetermined length dimension (front-rear direction dimension) inside the upper case 146, and protrudes to the vicinity of the lower opening of the upper case 146. In particular, in Embodiment 2, reinforcing ribs 152 extending in a direction (left-right direction) orthogonal to the length direction of the displacement restricting rib 150 are integrally formed at both front and rear ends of the displacement restricting rib 150 in the front-rear direction, and the deformation rigidity of the displacement restricting rib 150 is improved.

[0074] <lower case 148> The lower case 148 of Embodiment 2 also has the same shape as the lower case 100 in Embodiment 1 as a whole. As shown in FIG. 13, it includes a bottom wall portion 114 in which each opening window 28, 116 is formed to penetrate in the thickness direction (up-down direction). Further, insertion holes 30 are formed in communication with the opening window 28 at both front and rear ends of the opening window 28 in the front-rear direction. And a holding portion 142 in Embodiment 2 is provided at the peripheral edge of the opening window 28.

[0075] <holding portion 142> The opening window 28 is rectangular in plan view as described above. The holding portion 142 of the second embodiment is provided on each of a pair of opposing pieces (opposing pieces in the front-rear direction) of the opening window 28, and includes a protruding wall portion 154 that protrudes inward (i.e., upward) of the case 144. Further, the holding portion 142 is provided on one of the other pair of opposing pieces (opposing pieces in the left-right direction) of the opening window 28 (the left side in the second embodiment), and includes a positioning wall portion 156 that protrudes inward (i.e., upward) of the case 144. The positioning wall portion 156 has a substantially rectangular plate shape and has a front-rear dimension substantially equal to that of the opening window 28. Further, the holding portion 142 includes the above-described displacement restricting rib 150 provided on the upper case 146.

[0076] Specifically, each protruding wall portion 154 is provided on both sides in the front-rear direction of the opening window 28, that is, on the left side of each insertion hole 30. In particular, in the second embodiment, each protruding wall portion 154 is provided on both the left and right sides of the rear insertion hole 30, and a total of three protruding wall portions 154 are provided on the lower case 148. Further, as described above, the positioning wall portion 156 is provided on the left side of the opening window 28, and the positioning wall portion 156 and each protruding wall portion 154 on both sides in the front-rear direction are connected by each bending portion 126 as in the first embodiment. Therefore, in the second embodiment, an insertion window portion 129 that penetrates in the front-rear direction is formed between the opposing portions of each rear protruding wall portion 154. And in a state where the precharge resistor 22 is held by the holding portion 142, each held portion 94 in the precharge resistor 22 is placed on the protruding end surface 158 of each protruding wall portion 154.

[0077] Also, in Embodiment 2 as well, the upward protruding dimension C (the vertical dimension from the upper surface of the bottom wall portion 114 to the protruding end surface 158) of each protruding wall portion 154 (see FIG. 15) is made smaller than the upward protruding dimension B of each fixed portion 42 provided on the housing 12. Thus, in a state where the circuit unit 140 is fixed to the housing 12, each fixed portion 42 protrudes into the circuit unit 140 through each insertion hole 30 of the lower case 148, and each fixed portion 42 is disposed inward (upward) of the case 144 beyond the protruding end surface 158 of each protruding wall portion 154. In short, in a state where the circuit unit 140 is fixed to the housing 12, the upper surface of each fixed portion 42 is positioned above the protruding end surface 158 of each protruding wall portion 154.

[0078] <Displacement restricting piece 162> Furthermore, the holding portion 142 extends from the protruding tip portion (upper end portion) of the positioning wall portion 156 toward the heat generating component (precharge resistor 22) side, is disposed inward (upward) of the case 144 than the protruding end surface 158 of each protruding wall portion 154, and includes a displacement restricting piece 162 that is disposed to face the precharge resistor 22 with a gap 160 therebetween in the vertical direction. The displacement restricting piece 162 is generally in the shape of a substantially rectangular plate and has a predetermined left-right dimension and front-back dimension. Thereby, as also shown in FIG. 11, in the vertical projection, the upper surface 93a of the precharge resistor 22 and the displacement restricting piece 162 overlap each other.

[0079] <Assembly of circuit unit 140> Hereinafter, a specific example of the assembly method of the circuit unit 140 will be described. Note that the assembly method of the circuit unit 140 is not limited to the embodiments described below. Also, in the assembly method of the circuit unit 140, descriptions of portions having the same structure as in Embodiment 1 will be omitted.

[0080] In Embodiment 2, the precharge resistor 22 is brought close to the holding portion 142 of the lower case 148 to which each of the relays 18a and 18b and the precharge relay 20 is fixed, from the right. Then, each flange-like portion 90 in the metal case 82 is placed on the protruding end surface 158 of each protruding wall portion 154 constituting the holding portion 142, and each held portion 94 at both left and right ends in the lateral direction of each flange-like portion 90 is held by the holding portion 142. The approach of the precharge resistor 22 from the right (displacement to the left) to the holding portion 142 is restricted, for example, by the left wall portion in the metal case 82 coming into contact with the positioning wall portion 156. In particular, in the holding portion 142, since no protruding wall portion 154 is provided on the right side of the front insertion hole 30, the precharge resistor 22 with the electric wires 72 and 74 extending forward can be brought close to the positioning wall portion 156 from the right.

[0081] Then, with the precharge resistor 22 held on the holding portion 142, the upper case 146 is brought close from above as shown in FIG. 14, and the upper case 146 and the lower case 148 are overlapped as shown in FIGS. 15 and 16. Thereby, the uneven shapes of the outer peripheral portions of the upper case 146 and the lower case 148 are fitted together, and the circuit unit 140 of Embodiment 2 is completed.

[0082] That is, in the circuit unit 140 of Embodiment 2, the peripheral wall portion 84 of the heat generating component (pre-charge resistor 22) is disposed and positioned between the left-right direction facing surfaces of the positioning wall portion 156 and the displacement restricting rib 150 and between the front-rear direction facing surfaces of the pair of protruding wall portions 154 facing each other in the front-rear direction. Also, in this state, as described above, a displacement restricting piece 162 is positioned above the pre-charge resistor 22 with a gap 160 therebetween, and the extraction of the pre-charge resistor 22 held by the holding portion 142 upward is blocked. Therefore, in the circuit unit 140, the pre-charge resistor 22 is surrounded by the displacement restricting rib 150, each protruding wall portion 154, the positioning wall portion 156, and the displacement restricting piece 162, and the pre-charge resistor 22 is displaceable to some extent within these. As a result, at the time of assembling the circuit unit 140, the pre-charge resistor 22 is temporarily assembled inside the circuit unit 140.

[0083] <Assembly of the heat dissipation target (housing 12) in the circuit unit 140> The method of assembling the circuit unit 140 to the housing 12 is not limited, but a method similar to that of Embodiment 1 can be adopted. That is, the circuit unit 140 is overlapped on the upper surface 32 of the housing 12, and each fixed portion 42 protruding upward from the upper surface 32 is inserted into the circuit unit 140 through each insertion hole 30 provided in the lower case 148. Thereby, the upper surface of each fixed portion 42 abuts against each flange-shaped portion 90 of each metal case 82 from below, and these flange-shaped portions 90 (particularly, each held portion 94) are spaced upward from the protruding end surface 158 in the holding portion 142 (particularly each protruding wall portion 154). Then, through each insertion hole 112 in the upper case 146, a screw 44 is inserted into each screw insertion groove 92 and fastened to each screw fastening hole 46. Thereby, the assembly of the circuit unit 140 to the housing 12 is completed.

[0084] In the circuit unit 140 of Embodiment 2 having the structure as described above, since only the insertion direction of the pre-charge resistor 22 with respect to the holding portion 142 is different from that of the circuit unit 10 of Embodiment 1, the same effects as those of Embodiment 1 can be exhibited.

[0085] <Modification Example> As described above, as specific examples of the present disclosure, Embodiments 1 and 2 have been described in detail. However, the present disclosure is not limited to this specific description. Modifications, improvements, etc. within the scope that can achieve the object of the present disclosure are included in the present disclosure. For example, modification examples of the following embodiments are also included in the technical scope of the present disclosure.

[0086] (1) In the above embodiment, the heat dissipation target was the housing 12 of the battery pack, but it is not limited to this aspect. That is, the heat dissipation target may be a member that thermally contacts the heat-generating component when the circuit unit according to the present disclosure is mounted on the vehicle. For example, it may be a metal member constituting the vehicle body. In addition, in the heat dissipation target, the refrigerant flow path as described in the above embodiment may not be provided.

[0087] (2) In the above embodiment, the heat-generating component was constituted by the pre-charge resistor 22, but it is not limited to this aspect. The heat-generating component employed in the circuit unit according to the present disclosure may be a component that generates heat when energized. For example, it may be a relay, a fuse, a pre-charge relay, etc.

[0088] (3) In the above embodiment, in the bottom wall portions 114 of the lower cases 100 and 148, the opening window 28 and each insertion hole 30 were formed to communicate with each other, but the opening window and the insertion hole may be formed separately. In addition, the shape, size, number, etc. of the opening window and the insertion hole are not limited. The shape, size, number, etc. of the opening window can be appropriately set according to the heat-generating component, and the shape, size, number, etc. of the insertion hole can be appropriately set according to the fixed portion provided on the heat dissipation target.

[0089] (4) In the above embodiment, the structure of the pre-charge resistor (metal-clad resistor) that constitutes the heat-generating component is not limited as long as it has a metal case. In the above embodiment, the electric wires 72 and 74 extending from the pre-charge resistor 22 extended from one end (front end) in the length direction of the pre-charge resistor 22. However, for example, in the case of Embodiment 1 above, the two electric wires may extend from both sides in the length direction of the pre-charge resistor.

[0090] (5) In the above embodiment, the pre-charge circuit 68 was connected in parallel to the positive-side relay 18a, but the pre-charge circuit may be connected in parallel to the negative-side relay.

Description of Reference Numerals

[0091] 10 Circuit unit (Embodiment 1) 12 Housing (heat dissipation target) 14 Thermal contact portion 16 Fixing portion 18 Relay 18a Positive-side relay 18b Negative-side relay 20 Pre-charge relay 22 Pre-charge resistor (heat-generating component) 24 Case 26 Holding portion 28 Opening window 30 Insertion hole 32 Upper surface 34 Refrigerant flow path 36 Support portion 38 Bolt 40 Bolt fastening hole 42 Fixed portion 44 Screw 46 Screw fastening hole 48 Terminal portion 50 Bus bar for energization 50a~50d First to fourth bus bars for energization 52 Bolt 54a~54d Connection portions 56 Bolt 58 Main circuit 60a to 60d, 1st to 4th heat dissipation bus bars 62, Heat dissipation part 64, Insulating sheet 66, Elastic heat conduction member 68, Precharge circuit 70, 72, 74, Electric wires 76, Terminal 78, Screw 80, Terminal part 82, Metal case 84, Peripheral wall part 86, Upper wall part 88, Lower wall part 90, Flange-like part 92, Screw insertion groove 93a, Upper surface 93b, Lower surface 94, Held part 96, Elastic heat conduction member 98, Upper case 100, Lower case 102, Upper bottom wall part 104, Upper peripheral wall part 106a to 106d, Through windows 108, Bolt insertion hole 110, Mounting part 112, Insertion hole 114, Bottom wall part 116, Opening window 118, Bolt insertion hole 120, Mounting part 121, Lower surface 122, Frame body part 124, Side wall part 126, Bent part 128, Placing part 129, Insertion window part 130, Projecting end face 132, Deflection piece part 134, Locking claw part 136, Inclined surface 138, Gap 140, Circuit unit (Embodiment 2) 142, Holding part 144, Case 146, Upper case 148, Lower case 150 Displacement regulating rib 152 Reinforcing rib 154 Protruding wall portion 156 Positioning wall portion 158 Protruding end face 160 Gap 162 Displacement regulating plate

Claims

1. A heat generating component having a thermally contacting portion that thermally contacts a heat dissipation target and a fixing portion that is fixed to the heat dissipation target, a case that holds the heat generating component, a holding portion that protrudes inside the case and holds the heat generating component in the case, an opening window that penetrates the case and exposes the thermally contacting portion of the heat generating component to the outside of the case, an insertion hole that penetrates the case and into which a fixed portion provided on the heat dissipation target is inserted, and comprising: A circuit unit in which the fixing portion of the heat generating component is fixed to the fixed portion inserted into the insertion hole, so that the heat generating component is separated from the holding portion, and the thermally contacting portion of the heat generating component is thermally contacted with the heat dissipation target.

2. The circuit unit according to claim 1, wherein in a state of being fixed to the heat dissipation target, the thermally contacting portion of the heat generating component is in contact with the heat dissipation target via an elastic heat conducting member.

3. The holding portion includes a frame portion that surrounds the periphery of the opening window and protrudes inward of the case, and a held portion protruding from the peripheral wall portion of the heat generating component is placed on the protruding end surface of the frame portion. The circuit unit according to claim 1 or claim 2.

4. The holding portion includes a bending piece portion that protrudes more inward of the case than the frame portion and is deformable by bending on the outer peripheral side of the opening window. The bending piece portion has a locking claw portion provided at the protruding tip and protruding to the inner peripheral side of the opening window. By the bending piece portion being bent and deformed to the outer peripheral side, the assembly of the heat generating component to the frame portion is allowed. In a state where the held portion of the heat generating component is placed on the protruding end surface of the frame portion, the locking claw portion of the elastically restored bending piece portion overlaps the heat generating component with a gap in the protruding direction of the frame portion. The circuit unit according to claim 3.

5. The fixing portion of the heat generating component is provided at the same position as the held portion in the protruding direction of the frame portion. The circuit unit according to claim 3, wherein in a state of being fixed to the heat dissipation target, the fixed portion of the heat dissipation target is arranged inward of the case beyond the protruding end surface in the protruding direction of the frame portion.

6. The case includes a lower case provided with the opening window and an upper case that is overlapped with the lower case. The opening window has a rectangular shape. The holding portion includes protruding wall portions provided on a pair of opposing sides of the opening window and protruding inward of the case, a positioning wall portion provided on one of the other pair of opposing sides of the opening window and protruding inward of the case, and a displacement restricting rib provided on the upper case and disposed opposite to the positioning wall portion with the heat generating component interposed therebetween. The heat generating component is disposed and positioned between opposing surfaces of the positioning wall portion and the displacement restricting rib and between opposing surfaces of the protruding wall portions. The circuit unit according to claim 1 or claim 2, wherein a held portion protruding from a peripheral wall portion of the heat generating component disposed between the protruding wall portions is placed on a protruding end surface of the protruding wall portion.

7. The circuit unit according to claim 6, wherein the holding portion includes a displacement restricting piece that extends from a protruding tip portion of the positioning wall portion toward the heat generating component side, is disposed inward of the case from the protruding end surface of the protruding wall portion, and is disposed opposite to the heat generating component with a gap therebetween.

8. The fixing portion of the heat generating component is provided at the same position as the held portion in the protruding direction of the protruding wall portion. The circuit unit according to claim 6, wherein in a state of being fixed to the heat dissipation target, the fixed portion of the heat dissipation target is disposed inward of the case beyond the protruding end surface in the protruding direction of the protruding wall portion.

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