Heat dissipation structure of heat-generating components

Abstract

This document discloses a heat dissipation structure for heat-generating components that can exhibit good heat dissipation performance even in the case of high current, while suppressing increases in size and deterioration of mass production capabilities. [Solution] The heat dissipation structure 10 for the heat-generating component comprises a heat-generating component 14, a first busbar 16 and a second busbar 18, and a laminated busbar 20 including a connection portion 24, 32 that connects to the heat-generating component 14, a heat dissipation portion 28, 34 that thermally contacts the heat-dissipating object 26, and a bent portion 30, 36 provided between the connection portion 24, 32 and the heat dissipation portion 28, 34. The first busbar 16 has a structure in which the connection portion 24, the bent portion 30 and the heat dissipation portion 28 are integrated, and the second busbar 18 has a separation portion 38 that separates the heat dissipation portion 34 from the connection portion 32, and has a structure separated into a connection portion 32 side and a heat dissipation portion 34 side via the separation portion 38, and the heat dissipation portion 28 of the first busbar 16 and the heat dissipation portion 34 of the second busbar 18 are thermally in contact with the heat-dissipating object 26 in a state where they are superimposed on each other.

Description

Technical Field

[0001] The present disclosure relates to a heat dissipation structure for heat generating components.

Background Art

[0002] Conventionally, in the power supply path of a vehicle, there are mounted heat generating components that generate heat by energization such as a relay that switches the electrical connection state between a battery and an in-vehicle load. In recent years, with the increase in the current of vehicles, the heat generated from the heat generating components has also increased. Therefore, as described in Patent Document 1, a heat dissipation part is provided on a bus bar connected to the terminal part of the heat generating component, and the heat dissipation part of the bus bar is brought into thermal contact with a heat dissipation target arranged in the vicinity of a battery case or the like, so that the heat of the heat generating component is dissipated to the heat dissipation target via the bus bar. A heat dissipation structure has been adopted.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the conventional heat dissipation structure for heat generating components, in order to thermally contact the heat dissipation part of the bus bar connected to the terminal part of the heat generating component with the heat dissipation target, it is necessary to bend the bus bar in the middle of the extending direction so that the heat dissipation part faces the heat dissipation target. Due to the further increase in the current of vehicles in recent electric vehicles, hybrid vehicles, etc., the cross-sectional area of the heat dissipation path required to achieve sufficient heat dissipation of the heat generating component has also increased. Widening the bus bar to increase the cross-sectional area leads to an increase in the size of the bus bar and the product. Therefore, in order to secure the required cross-sectional area, the plate thickness dimension of the bus bar has to be increased. As a result, it becomes difficult to bend the bus bar that constitutes the heat dissipation path of the heat generating component itself, and there is a risk of deterioration in mass productivity.

[0005] Therefore, we disclose a heat dissipation structure for a heat-generating component that can exhibit good heat dissipation performance while suppressing the need for increased size and deterioration of mass production capabilities, even in the case of high current. [Means for solving the problem]

[0006] The heat dissipation structure for a heat-generating component of this disclosure comprises a heat-generating component that generates heat when an electric current is applied, and a first busbar and a second busbar that are stacked on top of each other in the thickness direction, wherein each of the first busbar and the second busbar is a laminated busbar that includes a connecting portion that connects to the terminal portion of the heat-generating component, a heat dissipation portion that is in thermal contact with the object to be heated, and a bent portion provided between the connecting portion and the heat dissipation portion, wherein the first busbar has a structure in which the connecting portion, the bent portion and the heat dissipation portion are connected and integrated in the longitudinal direction, and the second busbar has a separating portion that separates the heat dissipation portion from the connecting portion, and has a structure that is separated into the connecting portion side and the heat dissipation portion side via the separating portion, wherein the heat dissipation portion of the first busbar and the heat dissipation portion of the second busbar are in thermal contact with the object to be heated while stacked on top of each other in the thickness direction. [Effects of the Invention]

[0007] According to the heat dissipation structure of the heat-generating component disclosed herein, even in the case of high current, good heat dissipation performance can be achieved while suppressing increases in size and deterioration of mass production capabilities. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a perspective view showing the heat dissipation structure of a heat-generating component according to Embodiment 1. [Figure 2] Figure 2 is a plan view of the heat dissipation structure of the heat-generating component shown in Figure 1. [Figure 3] Figure 3 is a longitudinal cross-sectional view showing an enlarged view of the main part of the III-III section in Figure 2. [Figure 4] Figure 4 is an exploded perspective view of the heat dissipation structure of the heat-generating component shown in Figure 1. [Figure 5] Figure 5 is a longitudinal cross-sectional view of the heat dissipation structure of the heat-generating component according to Embodiment 2, and corresponds to Figure 3. [Figure 6] Figure 6 is a longitudinal cross-sectional view of the heat dissipation structure of a heat-generating component according to Embodiment 3, and corresponds to Figure 3. [Figure 7] Figure 7 is a perspective view showing the heat dissipation structure of the heat-generating component according to Embodiment 4. [Figure 8] Figure 8 is a longitudinal cross-sectional view showing an enlarged view of the main part of the VIII-VIII section in Figure 7. [Modes for carrying out the invention]

[0009] <Description of Embodiments in this Disclosure> First, embodiments of this disclosure will be listed and described. The heat dissipation structure of the heat-generating component in this disclosure is (1) A laminated busbar comprising a heat-generating component that generates heat when power is applied, and a first busbar and a second busbar that are stacked on top of each other in the thickness direction, wherein each of the first busbar and the second busbar includes a connecting portion that connects to the terminal portion of the heat-generating component, a heat-dissipating portion that is in thermal contact with the object to be heated, and a bent portion provided between the connecting portion and the heat-dissipating portion, wherein the first busbar has a structure in which the connecting portion, the bent portion and the heat-dissipating portion are connected and integrated in the longitudinal direction, and the second busbar has a separating portion that separates the heat-dissipating portion from the connecting portion, and has a structure that is separated into the connecting portion side and the heat-dissipating portion side via the separating portion, wherein the heat-dissipating portion of the first busbar and the heat-dissipating portion of the second busbar are in thermal contact with the object to be heated while stacked on top of each other in the thickness direction.

[0010] According to the heat dissipation structure for heat-generating components of this disclosure, the busbars that constitute the heat dissipation path from the heat-generating component to the heat-dissipating object, having a connecting portion that connects to the terminal portion of the heat-generating component and a heat dissipation portion that thermally contacts the heat-dissipating object, are composed of laminated busbars including a first busbar and a second busbar that are stacked on top of each other in the thickness direction. As a result, even when the required path cross-sectional area for the heat dissipation path increases due to high current, and the thickness dimension of the busbars must be increased, the adoption of laminated busbars allows for distribution between the first busbar and the second busbar while securing the necessary thickness dimension for the heat dissipation path. This makes it possible to keep the thickness dimensions of the first busbar and the second busbar smaller compared to when the heat dissipation path is composed of a single busbar, and it becomes easy to provide bent portions in each of the first and second busbars, thereby providing a heat dissipation structure for heat-generating components that suppresses increased size and deterioration of mass productionability.

[0011] Furthermore, the second busbar has a dividing section that separates the heat dissipation section from the connection section, and has a structure that separates the connection section side and the heat dissipation section side via the dividing section. This prevents the problem of difficulty in overlapping the heat dissipation sections of the first and second busbars, which are both connected to the terminal section of the heat-generating component, due to bending tolerances of the respective bent sections of the first and second busbars. As a result, the heat dissipation sections of the first busbar and the second busbar can be thermally contacted with the heat-dissipating object while overlapping each other in the thickness direction, providing a heat dissipation structure for a heat-generating component that exhibits good heat dissipation performance.

[0012] The stacked busbars include configurations in which a second busbar is superimposed on a first busbar, and configurations in which a second busbar is superimposed on a first busbar. Furthermore, the stacked busbars may be used exclusively for heat dissipation, or they may also serve as a power supply path.

[0013] (2) In (1) above, it is preferable that the divided portion of the second busbar is provided between the bent portion and the heat dissipation portion, and that the heat dissipation portion has a flat plate shape that does not include the bent portion. Because the divided portion of the second busbar is provided between the bent portion and the heat dissipation portion, and the heat dissipation portion has a flat plate shape that does not include the bent portion, it becomes possible to overlap the heat dissipation portion of the second busbar with the heat dissipation portion of the first busbar over a wider area and make surface contact, thereby further improving the heat dissipation performance.

[0014] (3) In (1) or (2) above, it is preferable that one surface of the heat dissipation portion of the second busbar is superimposed on the other surface of the heat dissipation portion of the first busbar which is superimposed on the heat dissipation object and is in fixed contact with it, and the end of the second busbar on the connection side of the dividing portion is superimposed on the other surface of the heat dissipation portion of the first busbar, either directly or via the heat dissipation portion of the second busbar and is in fixed contact with it. Since the heat dissipation portion of the second busbar separated from the connection portion by the dividing portion is superimposed on the surface of the heat dissipation portion of the first busbar which is superimposed on the heat dissipation object and is fixed to it, it is possible to maintain a wide surface contact state between the opposing surfaces of the heat dissipation portions of the first busbar and the second busbar while securing the cross-sectional area of ​​the entire heat dissipation portion of the laminated busbar, and good heat dissipation performance can be ensured. Furthermore, since the end of the second busbar on the connection side of the divided section is similarly overlapped and fixed to the heat dissipation section of the second busbar, the heat from the heat-generating component that has been transferred to the connection section of the second busbar can be transferred from the end on the connection side to the heat dissipation section of the first busbar and the heat dissipation section of the second busbar, thereby improving heat dissipation performance. Note that "fixed contact" can be achieved by bolting or welding.

[0015] (4) In any one of (1) to (3) above, it is preferable that a heat conductive member having elasticity is interposed between the opposing surfaces of the heat radiating portion of the first bus bar or the second bus bar and the object to be heat radiated. By interposing an elastic heat conductive member such as a gap filler between the opposing surfaces of the heat radiating portion of the first or second bus bar and the object to be heat radiated, it is possible to suppress deterioration of heat conductivity due to minute gaps between the contact surfaces, and further improve the heat radiation performance.

[0016] (5) In any one of (1) to (4) above, the laminated bus bar has an energization function, has a pair of the connection portions at both ends in the longitudinal direction, has the heat radiating portion at the central portion in the longitudinal direction, has a pair of the bent portions on both sides of the heat radiating portion in the longitudinal direction, and the heat radiating portion of the second bus bar is separated from the pair of the connection portions by a pair of the dividing portions provided between the bent portion and the heat radiating portion on both sides of the heat radiating portion in the longitudinal direction, and it is preferable that the heat radiating portion has a flat plate shape not including the bent portion. When the laminated bus bar is used as a bus bar for energization having an energization function, a flat plate-shaped heat radiating portion not including the bent portion is separated from the pair of the connection portions by a pair of the separating portions provided on both sides of the heat radiating portion of the second bus bar. Thereby, even when the laminated bus bar is used as a bus bar for energization having a pair of connection portions on both sides in the longitudinal direction, surface contact in a wide range from the heat radiating portion of the second bus bar to the heat radiating portion of the first bus bar can be realized, and a heat radiation path using the bus bar for energization can be realized with excellent heat radiation performance.

[0017] <Details of Embodiments of the Present Disclosure> A specific example of the heat radiation structure of the heat generating component 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 shown by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0018] <Embodiment 1> Hereinafter, the heat dissipation structure 10 of the heat generating component of Embodiment 1 of the present disclosure (hereinafter, the heat dissipation structure 10) will be described with reference to FIGS. 1 to 4. This heat dissipation structure 10 is provided, for example, in an electric vehicle, a hybrid vehicle, etc., and is adopted inside, for example, an electrical connection box 12 provided in a battery pack. With this heat dissipation structure 10, the heat generated by the heat generating component (relay 14 in Embodiment 1) arranged in the electrical connection box 12 can be stably dissipated. Note that the electrical connection box 12 in which the heat dissipation structure 10 is provided in the vehicle can be arranged in any orientation. Hereinafter, the upper side refers to the upper side in FIG. 3, the lower side refers to the lower side in FIG. 3, the left side refers to the left side in FIG. 2, the right side refers to the right side in FIG. 2, the front side refers to the lower side in FIG. 2, and the rear side refers to the upper side in FIG. 2 for explanation. Also, for a plurality of identical members, only some members may be labeled with reference numerals, and reference numerals may be omitted for other members.

[0019] <Heat dissipation structure 10 of heat generating component> The heat dissipation structure 10 of Embodiment 1 includes a relay 14 as a heat generating component that generates heat upon energization, and a laminated bus bar 20 including a first bus bar 16 and a second bus bar 18 that are overlapped with each other in the plate thickness direction. The first bus bar 16 includes a first connection portion 24 as a connection portion that connects to the terminal portion 22 of the relay 14, a first heat dissipation portion 28 as a heat dissipation portion that thermally contacts a heat dissipation target (the housing 26 of the battery pack in Embodiment 1), and a first bending portion 30 as a bending portion provided between the first connection portion 24 and the first heat dissipation portion 28. Similarly, the second bus bar 18 includes a second connection portion 32 as a connection portion that connects to the terminal portion 22 of the relay 14, a second heat dissipation portion 34 as a heat dissipation portion that thermally contacts a heat dissipation target (the housing 26 of the battery pack), and a second bending portion 36 as a bending portion provided between the second connection portion 32 and the second heat dissipation portion 34.

[0020] The first busbar 16 has a structure in which the first connection portion 24, the first bent portion 30, and the first heat dissipation portion 28 are connected and integrated in the longitudinal direction. The second busbar 18 has a dividing portion 38 that separates the second heat dissipation portion 34 from the second connection portion 32, and has a structure in which it is separated into the second connection portion 32 side and the second heat dissipation portion 34 side via the dividing portion 38. The first heat dissipation portion 28 in the first busbar 16 and the second heat dissipation portion 34 in the second busbar 18 are in thermal contact with the housing 26 of the battery pack, which is the target of heat dissipation, in a state where they are overlapping each other in the thickness direction of the plates.

[0021] <Electrical junction box 12> The structure of the electrical junction box 12 is not limited, but the electrical junction box 12 of Embodiment 1 has a structure in which a circuit configuration 40, which includes relays 14, is housed in a case 42. Specifically, the circuit configuration 40 of Embodiment 1 includes a pair of relays 14, 14 that are separated from each other in the left-right direction, and one terminal portion 22 of each of these relays 14 is connected to the other by a stacked busbar 20 which includes a first busbar 16 and a second busbar 18. The connection between the terminal portions 22 of each of these relays 14 and the stacked busbar 20 is made by bolts 44. In addition, a busbar 48 having an external connection portion 46 is connected to the other terminal portion 22 of each relay 14 by bolts 44. That is, in Embodiment 1, the circuit configuration 40 is composed of each relay 14, the stacked busbar 20 and each busbar 48, and the stacked busbar 20 has a heat dissipation function as well as an electrical conduction function. Each relay 14 is a known type, and in Embodiment 1, a mechanical relay (contact relay) is used.

[0022] In Embodiment 1, the case 42 is composed of an upper case and a lower case 50 that can be assembled and separated in the vertical direction, but the upper case is omitted in the figure. The lower case 50 is a roughly rectangular box shape that opens upward as a whole, and has a roughly rectangular flat bottom wall portion 52 and a peripheral wall portion 54 that protrudes upward from the outer peripheral edge of the bottom wall portion 52. Each relay 14 is superimposed on the bottom wall portion 52 of the lower case 50 and fixed, for example, by a bolt-nut structure. The first heat dissipation portion 28 and the second heat dissipation portion 34 of the stacked busbar 20 connecting each relay 14, 14 are in thermal contact with the bottom wall portion 52 of the lower case 50 in a superimposed state. The electrical connection box 12 is fixed with the bottom wall portion 52 of the lower case 50 superimposed on the housing 26 of the battery pack which is the target of heat dissipation, and as a result the bottom wall portion 52 and the housing 26 are in thermal contact. Therefore, in Embodiment 1, in addition to the housing 26, the bottom wall portion 52 of the lower case 50 may also be included as a heat dissipation target for the heat generated by each relay 14.

[0023] In Embodiment 1, a first heat conduction member 56 is provided between the first heat dissipation section 28 and the bottom wall section 52 as a heat conduction member. A second heat conduction member 58 is provided between the bottom wall section 52 and the housing 26 as a heat conduction member. These first heat conduction member 56 and second heat conduction member 58 are made of, for example, a synthetic resin with excellent thermal conductivity, and known heat conduction sheets with elasticity may be used. That is, in Embodiment 1, a first heat conduction member 56 with elasticity is provided between the opposing surfaces of the first heat dissipation section 28 and the bottom wall section 52 which is the heat to be dissipated. It is preferable that these first heat conduction member 56 and second heat conduction member 58 are compressed vertically by a member that sandwiches them vertically. This prevents gaps from forming between the first heat dissipation section 28 and the bottom wall section 52, and between the bottom wall section 52 and the housing 26.

[0024] <1st Bus Bar 16> As described above, the first busbar 16 has a structure in which the first connection portion 24, the first bent portion 30, and the first heat dissipation portion 28 are connected and integrated in the longitudinal direction. Furthermore, since the first busbar 16 connects a pair of relays 14, 14, the first busbar 16 has a pair of first connection portions 24, 24 connected to each relay 14, and a pair of first bent portions 30 connected from each of these first connection portions 24. In other words, the first busbar 16 is generally U-shaped, with a pair of first connection portions 24, 24 at both ends in the longitudinal direction, and a first heat dissipation portion 28 in the central part in the longitudinal direction, with a pair of first bent portions 30, 30 provided on both sides of this first heat dissipation portion 28 in the longitudinal direction. In Embodiment 1, the first busbar 16 is arranged to extend in the left-right direction, and at both ends in the left-right direction of the first heat dissipation section 28, which extends in the left-right direction, each first connection section 24 protrudes upward via each first bent section 30. Such a first busbar 16 is made of a metal with excellent conductivity, such as copper (including copper alloys) or aluminum (including aluminum alloys).

[0025] Each first connection portion 24 of the first busbar 16 has a bolt insertion hole 60 formed through it in the thickness direction (left-right direction), through which a bolt 44 for fixing to the terminal portion 22 of each relay 14 is inserted. Furthermore, as will be described later, the first heat dissipation portion 28 of the first busbar 16 is superimposed on the second heat dissipation portion 34 of the second busbar 18 and fixed by a pair of bolts 76, 76. As a result, bolt insertion holes 62 through which each bolt 76 is inserted are formed at both ends of the first heat dissipation portion 28 in the longitudinal direction (left-right direction), through which the bolts 76 are inserted. For example, the inner circumferential surface of the bolt insertion hole 62 may have a female thread that engages with the male thread of each bolt 76.

[0026] <2nd Bus Bar 18> The second busbar 18, as a whole, is roughly U-shaped and extends in the left-right direction, similar to the first busbar 16. However, as mentioned above, it is provided with a dividing section 38, separating it into a second connection section 32 side and a second heat dissipation section 34 side. In Embodiment 1, the dividing section 38 of the second busbar 18 is provided between the second bend section 36 and the second heat dissipation section 34. In particular, in Embodiment 1, a pair of dividing sections 38, 38 are provided separated from each other in the left-right direction, and each dividing section 38 is provided on both sides of the second heat dissipation section 34. These dividing sections 38 separate the second heat dissipation section 34 from each second connection section 32. In short, the second busbar 18 consists of a pair of L-shaped sections 64, 64 provided at both left and right ends that face the second connection section 32 side, and a flat plate-shaped second heat dissipation section 34 provided in the center in the left-right direction that faces the second heat dissipation section 34 side. Each L-shaped portion 64 and the second heat dissipation portion 34 constituting the second busbar 18 are formed from the same material as the first busbar 16. While the thickness dimensions of the first busbar 16 and the second busbar 18 are not limited, both have a certain thickness, and in Embodiment 1, the second busbar 18 is thicker than the first busbar 16. Furthermore, the first busbar 16 does not need to have a constant thickness along its entire length in the left-right direction; its thickness may vary in parts. Similarly, the thickness dimensions of each L-shaped portion 64 and the second heat dissipation portion 34 constituting the second busbar 18 may differ from each other, but in Embodiment 1, each L-shaped portion 64 and the second heat dissipation portion 34 are formed with approximately equal thickness.

[0027] Each L-shaped portion 64, 64 is the same shape as the others and is separated from each other in the left-right direction. Each L-shaped portion 64 includes a second connecting portion 32 that is superimposed on the terminal portion 22 of each relay 14 via each first connecting portion 24, each second bent portion 36 connected to each second connecting portion 32, and each flat portion 66 that extends flatly inward in the left-right direction from each second bent portion 36. In other words, a pair of flat portions 66, 66 are separated from each other by a predetermined distance in the left-right direction, and each second connecting portion 32 protrudes upward from both ends of each flat portion 66 in the left-right direction via each second bent portion 36. Each second connecting portion 32 has a bolt insertion hole 68 through which a bolt 44 for fixing to the terminal portion 22 of each relay 14 is inserted, and the bolt insertion hole 68 is formed in the thickness direction (left-right direction) of each second connecting portion 32. Furthermore, each flat portion 66 has a bolt insertion hole 70 through which the bolts 76 described later are inserted, extending in the thickness direction (vertical direction) of each flat portion 66.

[0028] The second heat dissipation section 34 of Embodiment 1 is a rectangular flat plate shape extending in the left-right direction and does not include the second bent section 36. The second heat dissipation section 34 is formed with a length dimension (left-right dimension) that spans each flat section 66 of each L-shaped section 64 which are separated from each other in the left-right direction. That is, when the first bus bar 16 and the second bus bar 18 are stacked and fixed together, the left-right ends of the second heat dissipation section 34 are sandwiched between each flat section 66 of each L-shaped section 64 and the first heat dissipation section 28 of the first bus bar 16, and the left-right ends of the second heat dissipation section 34 constitute an intermediate laminated section 72. Bolt insertion holes 74 through which bolts 76, which will be described later, are inserted are formed in each intermediate laminated section 72, penetrating in the thickness direction (vertical direction) of each intermediate laminated section 72.

[0029] <Stacked Busbar 20> The laminated busbar 20 is constructed by overlapping and fixing the first busbar 16 and the second busbar 18 described above. Specifically, the laminated busbar 20 has a pair of first connection parts 24 and a pair of second connection parts 32 provided at both ends in the longitudinal direction (left-right direction). The laminated busbar 20 also has a first heat dissipation part 28 and a second heat dissipation part 34 in the central part in the longitudinal direction. Furthermore, the laminated busbar 20 has a pair of first bent parts 30 and a pair of second bent parts 36 provided on both sides of each heat dissipation part 28, 34 in the longitudinal direction. In Embodiment 1, the first busbar 16 is superimposed on the second busbar 18, and specifically, the second heat dissipation part 34 and the flat parts 66 of each L-shaped part 64 are superimposed on the first heat dissipation part 28 of the first busbar 16. As a result, the laminated busbar 20 has a partially three-layer structure. The bolt insertion holes 62, 74, and 70 in the intermediate laminated sections 72 and flat sections 66 of the first heat dissipation section 28 and the second heat dissipation section 34 are interconnected in the vertical direction, and the first heat dissipation section 28, the second heat dissipation section 34 and the L-shaped sections 64 are fixed to each other by bolts 76 inserted through the bolt insertion holes 62, 74, and 70.

[0030] Here, the first heat dissipation section 28, the second heat dissipation section 34, and the flat sections 66 of each L-shaped section 64 are all flat in shape, and substantially the entire lower surface of the second heat dissipation section 34 is superimposed on the upper surface of the first heat dissipation section 28 in a state of surface contact. Similarly, substantially the entire lower surface of each flat section 66 is superimposed on the upper surface of the second heat dissipation section 34 in a state of surface contact. That is, one surface (lower surface) of the first heat dissipation section 28 is superimposed on the bottom wall 52 of the lower case 50, which is the target of heat dissipation, via the first heat conductive member 56, and the second heat dissipation section 34 is superimposed on the other surface (upper surface) of the first heat dissipation section 28 and is in fixed contact. Furthermore, the ends of the second busbar 18 on the second connection section 32 side (each flat section 66) are superimposed on the other surface (upper surface) of the first heat dissipation section 28 via the second heat dissipation section 34 and are in fixed contact.

[0031] Furthermore, each first connection portion 24 on the first busbar 16 and each second connection portion 32 on the second busbar 18 (each L-shaped portion 64) are superimposed in the left-right direction, which is the thickness direction, and the bolt insertion holes 60 on each first connection portion 24 and the bolt insertion holes 68 on each second connection portion 32 are in mutual communication in the left-right direction. Each of these first connection portions 24 and each second connection portion 32 is superimposed on the terminal portion 22 of each relay 14, and bolts 44 inserted through the bolt insertion holes 60, 68 are fastened to each terminal portion 22. In this way, the laminated busbar 20 consisting of the first busbar 16 and the second busbar 18 is electrically and thermally connected to each relay 14, which is a heat-generating component. Each of the first connection portions 24 and each second connection portion 32 has a flat shape, and substantially the entire left-right outer surface of each second connection portion 32 is superimposed on the left-right inner surface of each first connection portion 24 in a state of surface contact.

[0032] The electrical junction box 12, with the structure described above, is fixed to the battery pack housing 26, which is the target of heat dissipation, by overlapping the lower surface of the bottom wall portion 52 of the lower case 50 via the second heat conductive member 58, as previously mentioned. In addition, terminals provided on the ends of external electric wires (not shown) are connected to the external connection portion 46 of each busbar 48 connected to the other terminal portion 22 of each relay 14, thereby supplying power to the circuit configuration 40 inside the electrical junction box 12. When power is supplied to each relay 14, each relay 14 generates heat. The heat generated by each relay 14 is dissipated from the battery pack housing 26 via the first heat dissipation portion 28 and the second heat dissipation portion 34, the first heat conductive member 56, the bottom wall portion 52 of the lower case 50, and the second heat conductive member 58, which are overlapped with each other.

[0033] Here, according to the heat dissipation structure 10 for the heat-generating component of Embodiment 1, it is possible to avoid increasing the size of the electrical connection box 12 while achieving good mass productivity and heat dissipation performance. That is, when considering heat dissipation associated with the increased current of vehicles, simply making the busbars wider or increasing their thickness would inevitably lead to increased size and deterioration of mass productivity. However, the busbars connected to the heat-generating component (relay 14) are made into a laminated busbar 20 consisting of a first busbar 16 and a second busbar 18. This makes it possible to handle heat dissipation when a large current flows without making the busbars connected to the relay 14 particularly wider, and while ensuring the overall thickness of the laminated busbar 20. Furthermore, when providing a bend in the busbars connected to the relay 14, the bends (each first bend 30 and each second bend 36) can be provided on the first busbar 16 and second busbar 18, which have relatively small thickness dimensions, thereby improving the mass productivity of the laminated busbar 20 and, consequently, the electrical connection box 12.

[0034] In particular, in Embodiment 1, the second busbar 18 is separated into L-shaped sections 64 and second heat dissipation sections 34 at each dividing section 38, thereby improving heat dissipation performance. That is, for example, if the first busbar and second busbar are simply bent into a U-shape, bending tolerances would make it difficult to overlap the first busbar and second busbar without gaps, potentially resulting in a gap between the first heat dissipation section and the second heat dissipation section, thus degrading heat dissipation performance. In contrast, in Embodiment 1, the second heat dissipation section 34 is formed separately from each L-shaped section 64, and the second heat dissipation section 34 is sandwiched between the flat section 66 of each L-shaped section 64 and the first heat dissipation section 28 and fixed with bolts 76. As a result, the first heat dissipation section 28 and the second heat dissipation section 34, which are each flat in shape, can be superimposed with virtually no gaps. Furthermore, even if each flat section 66 lifts up from the second heat dissipation section 34 due to bending tolerances, the axial force (tightening force) of each bolt 76 allows each flat section 66 and the second heat dissipation section 34 to be superimposed with virtually no gaps. Consequently, no gaps occur at the overlapping portion of the first busbar 16 and the second busbar 18, and the heat generated in each relay 14 can be effectively dissipated through the first heat dissipation section 28 and the second heat dissipation section 34.

[0035] Each divided portion 38 of the second busbar 18 is provided between the second bent portion 36 and the second heat dissipation portion 34, and the second heat dissipation portion 34 has a flat plate shape that does not include the second bent portion 36. As a result, the lower surface of the second heat dissipation portion 34 can be in surface contact with the upper surface of the first heat dissipation portion 28 over almost its entire surface, and excellent heat dissipation performance can be achieved in heat dissipation through the first heat dissipation portion 28 and the second heat dissipation portion 34.

[0036] The second heat dissipation section 34 is superimposed on the other surface (upper surface) of the first heat dissipation section 28 and is in fixed contact with it, while one surface (lower surface) of the first heat dissipation section 28 is superimposed on the bottom wall 52 of the lower case 50, which is the object of heat dissipation, via the first heat conductive member 56 and is in fixed contact with it. In addition, the ends (each flat portion 66) of the second busbar 18 on the side of each second connection portion 32 rather than each division portion 38 are superimposed on the other surface (upper surface) of the first heat dissipation section 28 via the second heat dissipation section 34 and are in fixed contact with it. As a result, the heat generated in each relay 14 is not only transferred to the first heat dissipation section 28 through each first connection section 24 and each first bend section 30, but also to the second heat dissipation section 34 through each second connection section 32, each second bend section 36 and each flat section 66, thus enabling more efficient heat dissipation through the first heat dissipation section 28 and the second heat dissipation section 34.

[0037] A heat-conducting member (first heat-conducting member 56) with elasticity is provided between the opposing surfaces of the first heat-dissipating section 28 and the bottom wall section 52 of the lower case 50, which is the target of heat dissipation. This prevents gaps from forming between the first heat-dissipating section 28 and the bottom wall section 52, thereby enabling good heat dissipation performance.

[0038] In particular, in Embodiment 1, the laminated busbar 20 has not only a heat dissipation function but also a current-carrying function. The laminated busbar 20 is roughly U-shaped, with a heat dissipation section (first and second heat dissipation sections 28, 34) in the longitudinal center, and each connection section (first and second connection sections 24, 32) protruding upward from both ends via each bent section (first and second bent sections 30, 36). This eliminates the need to provide a separate busbar for current transport, and makes it possible to carry large currents through the laminated busbar 20, which has a relatively large cross-sectional area.

[0039] <Embodiment 2> Hereinafter, the heat dissipation structure 80 of the heat-generating component in Embodiment 2 of this disclosure (hereinafter referred to as the heat dissipation structure 80) will be described with reference to Figure 5. The basic structure of the heat dissipation structure 80 in Embodiment 2 is the same as that of Embodiment 1, but Embodiment 2 differs from Embodiment 1 in that the left and right ends of the second heat dissipation section 82 are not sandwiched between the flat sections 66 of each L-shaped section 64 and the first heat dissipation section 28 of the first busbar 16. Hereinafter, the differences from Embodiment 1 will be mainly described, and detailed explanations will be omitted for members and parts that are substantially the same as those in Embodiment 1, by denoting them with the same reference numerals as in Embodiment 1 in the figures.

[0040] In Embodiment 2, the first busbar 16 has the same shape as in Embodiment 1, but in the first heat dissipation section 28, bolt insertion holes 62 are formed not only at both ends in the longitudinal direction (left and right direction) but also in the longitudinal center.

[0041] <2nd Bus Bar 84> In Embodiment 2, the second busbar 84 is also provided with a pair of separating portions 38, 38 that separate the second heat dissipation portion 82 from each second connection portion 32, and the second busbar 84 is composed of a pair of L-shaped portions 64, 64 provided at both ends in the left-right direction and a flat plate-shaped second heat dissipation portion 82 provided in the center in the left-right direction. In Embodiment 1, the second heat dissipation portion 34 was formed with a left-right dimension that spanned the flat portion 66 of each L-shaped portion 64, but in Embodiment 2, the second heat dissipation portion 82 has a left-right dimension that is smaller than the distance between the opposing faces of the flat portions 66, 66 of each L-shaped portion 64. As a result, the second heat dissipation portion 82 is located between the flat portions 66, 66 that are separated from each other in the left-right direction, and the left-right inward end faces of each flat portion 66 and the left-right outward end faces of the second heat dissipation portion 82 are separated from each other in the left-right direction by a predetermined gap. The gaps between these flat sections and the second heat dissipation section 82 in the left-right direction constitute each of the above-mentioned dividing sections 38. In Embodiment 2, in addition to the flat sections 66 in each L-shaped section 64, bolt insertion holes 70 through which each bolt 76 is inserted are also formed in the left-right central portion of the second heat dissipation section 82.

[0042] In other words, in Embodiment 2, there is no second heat dissipation section 82 between the flat section 66 of each L-shaped section 64 and the first heat dissipation section 28. The ends of the second busbar 84 on the second connection section 32 side (each flat section 66) are directly superimposed on the other surface (upper surface) of the first heat dissipation section 28 by bolts 76 and are in fixed contact. The second heat dissipation section 82 is also directly superimposed on the upper surface of the first heat dissipation section 28 at the central part in the left-right direction of the first heat dissipation section 28 and fixed by bolts 76. As a result, the lower surface of the second heat dissipation section 82 is superimposed on the upper surface of the first heat dissipation section 28 with virtually no gap over almost its entire surface.

[0043] In the heat dissipation structure 80 of Embodiment 2, which has such a structure, the laminated busbar 86 is composed of a first busbar 16 and a second busbar 84 with relatively small thickness dimensions, so even though it has bent sections (each first bent section 30 and each second bent section 36), it exhibits excellent mass producibility. In particular, since each L-shaped section 64 and the second heat dissipation section 82 are separated by each dividing section 38, the bending tolerance at each second bent section 36 does not affect the second heat dissipation section 82, and the occurrence of a gap between the second heat dissipation section 82 and the first heat dissipation section 28 is reliably prevented. As a result, deterioration of heat dissipation performance through the first heat dissipation section 28 and the second heat dissipation section 82 can be avoided. Furthermore, the laminated busbar 86 of Embodiment 2 does not have a three-layer structure like the laminated busbar 20 of Embodiment 1, so the thickness dimension of the laminated busbar 86 at the fastening section of each bolt 76 can be made smaller compared to Embodiment 1.

[0044] <Embodiment 3> Hereinafter, the heat dissipation structure 90 of the heat-generating component in Embodiment 3 of this disclosure (hereinafter referred to as the heat dissipation structure 90) will be described with reference to Figure 6. The basic structure of the heat dissipation structure 90 in Embodiment 3 is the same as that of Embodiment 1, but Embodiment 3 differs from Embodiment 1 in that the first busbar 94 is located above the second busbar 92. Hereinafter, the differences from Embodiment 1 will be mainly described, and detailed explanations will be omitted for members and parts that are substantially the same as those in Embodiment 1, by denoting them with the same reference numerals as in Embodiment 1 in the figures.

[0045] In Embodiment 3, the first busbar 94 has the same shape as in the first embodiment, and is substantially U-shaped, with each first connecting portion 24 protruding upward via each first bent portion 30 at both ends in the longitudinal direction (left-right direction) of the first heat dissipation portion 28.

[0046] <2nd Bus Bar 92> In Embodiment 3, the second busbar 92 also has a dividing portion 38 that separates each L-shaped portion 64 on the second connection portion 32 side from the second heat dissipation portion 34, similar to Embodiment 1. In Embodiment 1, the second heat dissipation portion 34 was superimposed on the lower surface of the flat portion 66 of each L-shaped portion 64, but in Embodiment 3, the second heat dissipation portion 34 is superimposed on the upper surface of each flat portion 66, and further superimposed on the upper surface of the second heat dissipation portion 34 is the first heat dissipation portion 28. That is, in Embodiment 3 as well, the second heat dissipation portion 34 is formed with a left-right dimension that spans each flat portion 66, 66 on both the left and right sides, and intermediate stacked portions 72 are formed by the left and right ends of the second heat dissipation portion 34.

[0047] Therefore, in Embodiment 3, at the fastening portion of each bolt 76, the first heat dissipation portion 28, the second heat dissipation portion 34, and each flat portion 66 are stacked in that order from above to form a three-layer structure, and the overlapping surfaces are in contact with virtually no gaps. As a result, the first busbar 94 and the second busbar 92 are electrically and thermally connected. Furthermore, the flat portions 66 of each L-shaped portion 64 of the second busbar 92 are in thermal contact with the bottom wall portion 52 of the lower case 50, which is the target of heat dissipation, via the first heat conductive member 56. In other words, each flat portion 66 and the first heat conductive member 56 are provided between the opposing surfaces of the second heat dissipation portion 34 and the bottom wall portion 52, which is the target of heat dissipation.

[0048] In the heat dissipation structure 90 of Embodiment 3, which has the structure described above, the first heat dissipation section 28 and the second heat dissipation section 34 are in an overlapping state and are in thermal contact with the heat to be dissipated (bottom wall section 52) via the respective flat sections 66, so that the same effects as in Embodiment 1 can be achieved. In particular, since each of the division sections 38 is provided in the second busbar 92, even when the second bent section 36 is provided, the first heat dissipation section 28 and the second heat dissipation section 34 can be brought into contact with virtually no gap, and a decrease in heat dissipation performance can be avoided.

[0049] <Embodiment 4> Hereinafter, the heat dissipation structure 100 for the heat-generating component of Embodiment 4 of this disclosure (hereinafter referred to as the heat dissipation structure 100) will be described with reference to Figures 7 and 8. In Embodiment 1, a stacked busbar 20 was used as a busbar connecting a pair of relays 14, 14. In Embodiment 4, however, one relay 14 is provided inside the electrical connection box 102, and one end (left end) of the stacked busbar 104 is connected to the terminal portion 22 of the relay 14, while the other end (right end) of the stacked busbar 104 is configured as an external connection portion 46. This stacked busbar 104 is configured to include a first busbar 106 and a second busbar 108, similar to Embodiment 1.

[0050] <Bus Bar 106> The first busbar 106 in Embodiment 4 has an overall shape similar to the first busbar 16 in Embodiment 1, and is substantially U-shaped. That is, the first busbar 106 is equipped with a first heat dissipation section 28 that extends in the left-right direction, and portions that protrude upward from both left and right ends of this first heat dissipation section 28 extend via each first bent portion 30. At the left end of the first busbar 106, the portion that protrudes upward from the first bent portion 30 is the first connection portion 24 that is connected to the terminal portion 22 of the relay 14. At the right end of the first busbar 106, an external connection portion 46 is formed by a portion that protrudes upward from the first bent portion 30 and protrudes outward (to the right) in the left-right direction from its upper end.

[0051] <2nd Bus Bar 108> In Embodiment 2, the second busbar 108 is a substantially L-shaped member that extends in the left-right direction as a whole, with a dividing portion 38 provided in the middle portion in the longitudinal direction (left-right direction), and is composed of an L-shaped portion 64 which is the member on the second connection portion 32 side and a second heat dissipation portion 34. Similar to Embodiment 1, the second heat dissipation portion 34 is substantially flat in shape, and the L-shaped portion 64 is superimposed from above on one end (left end) of the second heat dissipation portion 34, thereby forming a substantially L-shaped second busbar 108 as a whole.

[0052] <Laminated busbar 104> The laminated busbar 104 is formed by overlapping and fixing the first busbar 106 and the second busbar 108. Specifically, the second heat dissipation section 34 is superimposed on the first heat dissipation section 28 of the first busbar 106 from above, and the L-shaped section 64 is further superimposed on the left end of the second heat dissipation section 34 from above. As a result, the left end of the second heat dissipation section 34 is sandwiched between the first heat dissipation section 28 and the flat section 66 of the L-shaped section 64, forming an intermediate laminated section 72, and the three layers of the first heat dissipation section 28, the second heat dissipation section 34 and the flat section 66 are fixed together by bolts 76. On the other hand, the right end of the second heat dissipation section 34 is only superimposed on the first heat dissipation section 28, and the two layers of the first heat dissipation section 28 and the second heat dissipation section 34 are fixed together by bolts 76.

[0053] In the heat dissipation structure 100 of Embodiment 4, which has the structure described above, the laminated busbar 104 is composed of a first busbar 106 and a second busbar 108 with relatively small thickness dimensions, so the same effects as in Embodiment 1 can be achieved. Furthermore, even if a second bent portion 36 is provided on the second busbar 108, the first heat dissipation portion 28 and the second heat dissipation portion 34 can be overlapped with virtually no gap, thereby avoiding a decrease in heat dissipation performance.

[0054] <Variation> While Embodiments 1 to 4 have been described in detail above as specific examples of the present disclosure, the present disclosure is not limited by these specific descriptions. Modifications, improvements, etc., to the extent that they can achieve the objectives of the present disclosure are included in the present disclosure. For example, the following modifications of embodiments are also included in the technical scope of the present disclosure.

[0055] (1) In Embodiment 1, the first busbar 16 and the second busbar 18 were fixed by bolts 76. However, the method of fixing the first busbar and the second busbar is not limited to bolt fixing. They may be fixed by welding, such as laser welding, or by other known fixing methods. The same applies to Embodiments 2 to 4.

[0056] (2) In Embodiment 1, the thickness dimension of the second busbar 18 was greater than that of the first busbar 16. However, the embodiment is not limited to this, and the thickness dimensions of the first busbar and the second busbar may be equal to each other, or the thickness dimension of the second busbar may be smaller than that of the first busbar. Note that the first busbar has first bends at two locations within its member, while the second busbar has a second bend at one location in each L-shaped section. Therefore, the first busbar undergoes bending more times within a single member, and when comparing the thickness dimensions of the second busbar and the first busbar, it is preferable that the thickness dimension of the first busbar is smaller. Furthermore, the thickness dimensions of both the first busbar and the second busbar may differ in the longitudinal direction according to their heat dissipation characteristics. For example, the thickness dimensions of each L-shaped section and the second heat dissipation section constituting the second busbar may differ. The same applies to Embodiments 2 to 4.

[0057] (3) In Embodiment 1, the stacked busbars 20 (first busbar 16 and second busbar 18) had both a heat dissipation function and a power supply function. However, the stacked busbars may have only a heat dissipation function, and the power supply function may be performed by a separately provided power supply busbar. The same applies to Embodiments 2 to 4.

[0058] (4) The first heat dissipation part in the first busbar and the second heat dissipation part in the second busbar only need to be in thermal contact, and a heat conductive member with elasticity may be provided between the first heat dissipation part and the second heat dissipation part. This can more reliably prevent a gap from forming between the first heat dissipation part and the second heat dissipation part. This heat conductive member may also have electrical insulating properties, and the first busbar having the first heat dissipation part and the second busbar having the second heat dissipation part do not need to be electrically connected.

[0059] (5) The first busbar and the second busbar are not limited to a two- or three-layer laminated structure. For example, the second heat dissipation section 34 in Embodiment 1 may be made into a two- or more-layer laminated structure, resulting in an overall laminated structure of four or more layers. Furthermore, in Embodiments 3 and 4, the configuration of Embodiment 2 may be combined and adopted. That is, in Embodiments 3 and 4, the second heat dissipation section may be superimposed on the first heat dissipation section rather than on the flat section of the L-shaped section.

[0060] (6) In the above embodiment, a relay 14 was described as a heat-generating component, but this is merely an example, and other known heat-generating components such as fuses or resistors may be used. Furthermore, even if the heat-generating component is a relay, it is not limited to a mechanical relay (contact relay) as in the above embodiment, but may also be a semiconductor relay (contactless relay). [Explanation of Symbols]

[0061] 10. Heat dissipation structure (for heat-generating components) (Embodiment 1) 12. Electrical junction box 14. Relays (heat-generating components) 16. First bus bar 18. Second bus bar 20-layer busbar 22 Terminal section 24. First connection section (connection section) 26. (Battery pack) casing (heat dissipation target) 28 1st heat dissipation section (heat dissipation section) 30 1st bending part (bending part) 32 Second connection section (connection section) 34 Second heat dissipation section (heat dissipation section) 36 2nd bending part (bending part) 38. Divided section 40 Circuit constructs 42 cases 44 volts 46 External connection section 48 Bus Bar 50 Lower Cases 52 Bottom wall section (heat dissipation target) 54 Peripheral wall section 56. First heat conduction member (heat conduction member) 58. Second heat conduction member (heat conduction member) 60, 62 Bolt insertion holes 64 L-shaped part 66 Flat area 68, 70 Bolt insertion holes 72 Intermediate laminate 74 Bolt insertion holes 76 volts 80 Heat dissipation structure (for heat-generating components) (Embodiment 2) 82 Second heat dissipation section 84 Second Bus Bar 86 Laminated Busbars 90 Heat dissipation structure (for heat-generating components) (Embodiment 3) 92 Second Bus Bar 94 First Bus Bar 100 Heat dissipation structure (for heat-generating components) (Embodiment 4) 102 Electrical junction box 104 Laminated Busbars 106 First Bus Bar 108 Second Bus Bar

Claims

1. A heat-generating component that generates heat when power is applied, The laminated busbar comprises a first busbar and a second busbar that are stacked on top of each other in the thickness direction, wherein each of the first busbar and the second busbar includes a connecting portion that connects to the terminal portion of the heat-generating component, a heat-dissipating portion that thermally contacts the heat-dissipating object, and a bent portion provided between the connecting portion and the heat-dissipating portion. The first busbar has a structure in which the connecting portion, the bent portion, and the heat dissipation portion are connected in the longitudinal direction and integrated together. The second busbar has a dividing portion that separates the heat dissipation portion from the connection portion, and has a structure that separates the connection portion side and the heat dissipation portion side via the dividing portion. A heat dissipation structure for a heat-generating component, wherein the heat dissipation portion of the first busbar and the heat dissipation portion of the second busbar are in thermal contact with the heat-dissipating object while overlapping each other in the plate thickness direction.

2. The heat dissipation structure for a heat-generating component according to claim 1, wherein the divided portion of the second busbar is provided between the bent portion and the heat dissipation portion, and the heat dissipation portion has a flat plate shape that does not include the bent portion.

3. The heat dissipation portion of the second busbar is fixedly in contact with the other surface of the heat dissipation portion of the first busbar, which is superimposed on the heat dissipation object, with one surface superimposed on the object to be heat dissipated. The heat dissipation structure for a heat-generating component according to claim 1 or claim 2, wherein the end of the second busbar on the connection side of the divided portion is in fixed contact with the other surface of the heat dissipation portion of the first busbar, either directly or via the heat dissipation portion of the second busbar.

4. A heat dissipation structure for a heat-generating component according to claim 1 or 2, wherein an expandable and contractible heat conductive member is interposed between the opposing surfaces of the heat dissipation portion of the first busbar or the second busbar and the heat-dissipating object.

5. The stacked busbar has an electrical conductivity function, has a pair of connection parts at both ends in the longitudinal direction, has a heat dissipation part in the central part in the longitudinal direction, and has a pair of bent parts on both sides of the heat dissipation part in the longitudinal direction. The heat dissipation structure for a heat-generating component according to claim 1 or claim 2, wherein the heat dissipation portion of the second busbar is separated from the pair of connecting portions by a pair of dividing portions provided between the bent portion and the heat dissipation portion on both sides of the heat dissipation portion in the longitudinal direction, and the heat dissipation portion has a flat plate shape that does not include the bent portion.

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