Circuit unit

Abstract

To provide a circuit unit that can suppress thermal effects on a battery module while an enclosure stores a battery pack.SOLUTION: A circuit unit 10 is mounted inside a battery pack 12 where a battery module 16 is stored in an enclosure 20. The circuit unit includes a circuit configuration part 30, a fan motor 32, a case 34, a suction hole 36, an exhaust hole 38, and an exhaust-air-direction restriction part 40, the circuit configuration part comprising a heating component 14, the case storing the circuit configuration part 30 and the fan motor 32, the suction hole provided on an upstream side of blowing directions α,β of the fan motor 32 in the case 34, the exhaust hole provided on a downstream side of the blowing directions α,β of the fan motor 32 in the case 34, the exhaust-air-direction restriction part guiding the exhaust air from the exhaust hole 38 in a direction away from the battery module 16.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] Patent Document 1 discloses a relay unit as a circuit unit that is mounted on a vehicle and disposed in a power supply path from a power source to a load. The relay unit in Patent Document 1 includes a fan motor, and employs a structure that promotes heat dissipation from the relay by cooling a heat dissipation component fixed to the terminal of the relay, which is a heat generating component, with air blown by the fan motor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-206601 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in recent years, a circuit unit equipped with a heat-generating component such as a relay as exemplified in Patent Document 1 may be housed inside a battery pack, which is one of the power sources mounted on a vehicle. In such a case, since a battery module is also housed inside the housing of the battery pack, it is necessary to reduce as much as possible the thermal effect of the circuit unit housed inside the housing on the battery module, and some kind of measure has been required.

[0005] In view of this, a circuit unit is disclosed that can suppress the thermal effect on the battery module while being housed in the housing of the battery pack. [Means for solving the problem]

[0006] The circuit unit of the present disclosure is a circuit unit mounted inside a battery pack in which a battery module is housed within a housing, and comprises a circuit configuration section including heat-generating components, a fan motor, and a case that houses the circuit configuration section and the fan motor, the case having an intake hole provided upstream of the air blowing direction of the fan motor and an exhaust hole provided downstream, and an exhaust direction regulating section that directs exhaust air from the exhaust hole in a direction away from the battery module. Effect of the Invention

[0007] According to the circuit unit of the present disclosure, it is possible to suppress the thermal effect on the battery module while it is housed in the housing of the battery pack. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing a battery pack including a circuit unit according to the first embodiment with a lid that constitutes a housing removed. [Diagram 2] FIG. 2 is an enlarged plan view showing a main part of the battery pack shown in FIG. [Diagram 3] FIG. 3 is a perspective view showing a positive pole main body constituting a positive pole circuit unit which is one of the circuit units according to the first embodiment. [Figure 4] FIG. 4 is a perspective view showing the positive electrode main body shown in FIG. 3 with an upper case that constitutes a case removed. [Diagram 5] FIG. 5 is a plan view showing the positive electrode main body shown in FIG. 3 with an upper case that constitutes a case removed. [Figure 6] 6 is a vertical cross-sectional view of the positive electrode main body shown in FIG. 3, and is an enlarged view of the VI-VI cross section in FIG. [Figure 7] 7 is a vertical cross-sectional view of the positive electrode main body shown in FIG. 3, and is an enlarged view of the VII-VII cross section in FIG. [Figure 8]FIG. 8 is an exploded perspective view of the positive electrode main body shown in FIG. [Figure 9] FIG. 9 is an exploded perspective view showing a circuit configuration portion constituting the positive electrode main body shown in FIG. 3 in an exploded state. [Figure 10] FIG. 10 is a perspective view showing a state in which an upper case constituting a case in a negative electrode main body of a negative electrode circuit unit, which is another one of the circuit units according to the first embodiment, is removed. [Figure 11] FIG. 11 is a plan view showing the negative electrode main body shown in FIG. 10 with an upper case that constitutes a case removed. [Figure 12] 12 is a vertical cross-sectional view of the negative electrode main body shown in FIG. 10, and is an enlarged view of the XII-XII cross section in FIG. [Figure 13] FIG. 13 is an exploded perspective view of the negative electrode main body shown in FIG. [Figure 14] FIG. 13 is an exploded perspective view showing a circuit configuration portion constituting the negative electrode main body shown in FIG. 10 in an exploded state. [Figure 15] FIG. 15 is a perspective view showing a positive pole main body constituting a positive pole circuit unit which is one of the circuit units according to the second embodiment. [Figure 16] FIG. 16 is a perspective view showing the positive electrode main body shown in FIG. 15 with an upper case that constitutes a case removed. [Figure 17] FIG. 17 is a perspective view showing the positive electrode main body shown in FIG. 16 from the rear side. [Figure 18] FIG. 18 is a plan view of the positive electrode main body shown in FIG. [Figure 19] FIG. 19 is an enlarged longitudinal sectional view showing a cross section taken along line XIX-XIX in FIG. [Figure 20] FIG. 20 is an enlarged longitudinal sectional view showing a cross section taken along line XX-XX in FIG. [Figure 21] FIG. 21 is an exploded perspective view of the positive electrode main body shown in FIG. [Figure 22] 22 is an enlarged perspective view showing a main part of the exploded perspective view of the positive electrode main body shown in FIG. [Figure 23] FIG. 23 is a perspective view showing a state in which an upper case constituting a case in a positive pole main body constituting a positive pole circuit unit, which is one of the circuit units according to the third embodiment, is removed. [Figure 24] 24 is an enlarged exploded perspective view showing a main part of the positive electrode main body shown in FIG. 23 in an exploded state. [Diagram 25] FIG. 25 is a vertical cross-sectional view of a positive pole main body constituting a positive pole circuit unit which is one of the circuit units according to the first modification of the third embodiment, and corresponds to FIG. [Figure 26] FIG. 26 is an enlarged exploded perspective view showing a main part of the positive electrode main body shown in FIG. 25 in an exploded state. [Figure 27] FIG. 27 is a perspective view showing a state in which an upper case constituting a case in a positive pole main body constituting a positive pole circuit unit which is one of the circuit units according to the second modification of the third embodiment is removed. [Figure 28] FIG. 28 is an enlarged exploded perspective view showing a main part of the positive electrode main body shown in FIG. 27 in an exploded state. [Figure 29] FIG. 29 is a perspective view showing a state in which an upper case constituting a case in a positive pole main body constituting a positive pole circuit unit, which is one of the circuit units according to the fourth embodiment, is removed. [Diagram 30] FIG. 30 is a plan view of the positive pole main body shown in FIG. [Diagram 31] FIG. 31 is an exploded perspective view of the positive electrode main body shown in FIG. [Diagram 32] FIG. 32 is an exploded perspective view showing the positive electrode main body shown in FIG. 29 from the rear side. [Diagram 33] FIG. 33 is a perspective view showing a circuit unit according to another embodiment of the present disclosure, the upper diagram showing the hinge opening / closing part in an open state and the lower diagram showing the hinge opening / closing part in a closed state. [Diagram 34] FIG. 34 is a plan view showing a circuit unit according to still another embodiment of the present disclosure housed in a battery pack. [Diagram 35] FIG. 35 is a perspective view showing a positive electrode circuit unit, which is one of the circuit units according to still another embodiment of the present disclosure, with an upper case that constitutes a case removed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] <Description of the embodiments of the present disclosure> First, embodiments of the present disclosure will be listed and described. The circuit unit of the present disclosure includes: (1) A circuit unit mounted inside a battery pack in which a battery module is housed within a housing, the circuit unit comprising: a circuit configuration section including heat-generating components; a fan motor; a case housing the circuit configuration section and the fan motor; an intake hole provided on the upstream side of the case in the air blowing direction of the fan motor; an exhaust hole provided on the downstream side of the case in the air blowing direction of the fan motor; and an exhaust direction regulating section that directs exhaust air from the exhaust hole in a direction away from the battery module.

[0010] According to this aspect, even when the air inside the case heated by the heat generating components is exhausted from the exhaust hole provided in the case by the fan motor, the exhaust from the exhaust hole is directed in a direction away from the battery module in the battery pack by the exhaust direction restricting portion provided in the circuit unit, thereby making it possible to provide a circuit unit that can suppress the thermal effect on the battery module housed in the battery pack even when used in a state housed in the housing of the battery pack.

[0011] Here, the exhaust direction regulating portion may be provided separately from the case, or may be provided in the case. For example, an exhaust direction regulating portion having a vane shape may be disposed at a position facing the exhaust hole, or an exhaust direction regulating portion having a vane shape may be integrally provided at a position facing the exhaust hole in the wall of the housing of the battery pack. Alternatively, the side of the exhaust hole provided in the case may be configured as an inclined surface that is inclined with respect to the blowing direction of the fan motor, or an air deflector disposed to face the exhaust hole of the case may be integrally provided or assembled to the case.

[0012] (2) In the above (1), it is preferable that the heat generating component includes a first heat generating component having a heat sink thermally connected to a terminal portion, and the first heat generating component and the heat sink are disposed downstream of the fan motor in the air blowing direction. Heat generated by the heat generating component is efficiently transferred to the heat sink from the terminal portion, where heat is transferred most, and heat dissipation from the heat sink is further promoted by utilizing the air blown by the fan motor. This advantageously improves the heat dissipation of the heat generating components in the circuit unit.

[0013] (3) In the above (2), it is preferable that the heat generating component includes a second heat generating component arranged upstream of the fan motor in the airflow direction, and the heat generation amount of the second heat generating component is smaller than the heat generation amount of the first heat generating component. There are cases where the fan motor cannot be arranged at the end of the circuit unit due to requirements such as space and circuit configuration in the battery pack. Even in such a case, by arranging the second heat generating component, which generates a smaller heat generation amount than the first heat generating component, upstream of the fan motor in the airflow direction, it is possible to efficiently dissipate heat from the first heat generating component, which generates a larger heat generation amount, by utilizing the airflow from the fan motor while satisfactorily satisfying the conditions on the intake side of the fan motor.

[0014] (4) In any one of (1) to (3) above, it is preferable that the heat-generating component is disposed downstream of the fan motor in the air blowing direction, and not upstream of the fan motor. By disposing the heat-generating component downstream of the fan motor, but not upstream, it is possible to prevent a problem in advance, such as the temperature of the intake side of the fan motor rising due to the heat-generating component and exceeding the upper operating temperature limit of the fan motor.

[0015] (5) In the above (2) or (3), it is preferable that the first heat generating component is a relay, the heat sink includes a plurality of heat sink plates protruding from the terminal portion, and the protruding height of the heat sink plates from the terminal portion is greater than the protruding height of the insulating partition plate protruding from the terminal portion of the relay. Since the protruding height of the heat sink heat sink plates from the terminal portion is greater than the protruding height of the insulating partition plate protruding from the terminal portion of the relay, it is possible to prevent a problem in which the air blown from the fan motor is blocked by the insulating partition plate and does not reach the heat sink arranged downstream of the insulating partition plate in the air blowing direction. As a result, the heat can be dissipated from all of the plurality of heat sink plates by the air blown from the fan motor, and the heat dissipation efficiency of the circuit unit can be further improved.

[0016] (6) In any one of the above (1) to (5), it is preferable that the case includes an airflow path extending from the fan motor toward the downstream side in the airflow direction of the fan motor, the heat-generating component is disposed in the airflow path, and the airflow path is configured to include a partition plate disposed in the case and partitioning the internal space of the case. An airflow path is provided that extends in the airflow direction of the fan motor and extends from the fan motor toward the downstream side, and the heat-generating component is disposed in the airflow path. This allows the airflow from the fan motor to be stably guided toward the downstream heat-generating component. Furthermore, since the airflow path is configured to include a partition plate that partitions the internal space of the case, the airflow path can be configured by separating it from other areas in the case, and the airflow from the fan motor can be efficiently directed toward the heat-generating component in the airflow path. As a result, the heat dissipation efficiency of the circuit unit can be further improved.

[0017] (7) In (6) when any one of (2), (3) and (5) above is cited, it is preferable that the upstream opening of the airflow path has a size that surrounds the fan motor, and the downstream opening of the airflow path has a size that surrounds the heat sink or the first heat generating component including the heat sink. The airflow path surrounds the fan motor at the upstream opening, and surrounds the heat sink or the first heat generating component including the heat sink at the downstream opening. Therefore, the airflow from the fan motor can be stably guided to the entire heat sink or the entire first heat generating component including the heat sink, and the heat dissipation of the circuit unit can be further improved. In particular, by using the airflow path of this aspect, even if the heat sink is larger than the fan motor, the entire heat sink can be reliably cooled by the airflow from the fan motor.

[0018] (8) In any one of the above (2), (3), (5) and (7), it is preferable that the fan motor includes an airflow path extending from the fan motor toward the downstream side in the airflow direction of the fan motor, the heat-generating component is disposed in the airflow path, and the cross-sectional area of ​​the airflow path in a direction perpendicular to the airflow direction is constant in a region of the airflow path from the fan motor to the heat sink. An airflow path is provided that extends in the airflow direction of the fan motor and toward the downstream side from the fan motor, and a heat-generating component is disposed in the airflow path. This allows the airflow of the fan motor to be stably guided toward the downstream heat-generating component. Furthermore, by making the cross-sectional area of ​​the airflow path perpendicular to the airflow direction constant in the region from the fan motor to the heat sink, the airflow of the fan motor can be efficiently guided to the heat sink while suppressing loss, and the heat dissipation of the circuit unit can be further improved.

[0019] (9) In any one of (1) to (8) above, it is preferable that the fan motor includes an airflow path extending from the fan motor toward the downstream side in the airflow direction of the fan motor, the heat-generating component includes a relay having a coil housed in a case body, and the airflow path includes a body cooling path that blows air onto a surface of the case body of the relay. In the case where the heat-generating component is a relay, by including the body cooling path in the airflow path, the heat generated by the coil can be cooled by airflow, and the heat dissipation of the relay, which is a heat-generating component, can be more effectively promoted by utilizing the airflow from the fan motor.

[0020] (10) In any one of the above (1) to (9), it is preferable that the intake hole of the case includes a plurality of intake slits penetrating the case, the exhaust hole of the case includes a plurality of exhaust slits penetrating the case, the total cross-sectional area of ​​the intake slits is equal to or larger than the cross-sectional area perpendicular to the axis of the fan motor, and the total cross-sectional area of ​​the exhaust slits is equal to or larger than the cross-sectional area perpendicular to the axis of the fan motor. This is because, by making the total cross-sectional area of ​​the intake slits constituting the intake hole provided in the case and the total cross-sectional area of ​​the exhaust slits constituting the exhaust hole equal to or larger than the cross-sectional area perpendicular to the axis of the fan motor, the fan motor can smoothly circulate air inside the case.

[0021] (11) In (10) when any one of the above (2), (3), (5), (7), and (8) is cited, it is preferable that the heat sink includes a plurality of heat sink plates arranged in parallel, and at least one of the exhaust slits is arranged facing a gap between the heat sink plates. This is because air can be smoothly blown from the gap between the plurality of heat sink plates constituting the heat sink to the exhaust slit, and the heat dissipation of the heat sink and the heat generating components by the air blown by the fan motor can be more reliably improved.

[0022] (12) In any one of the above (2), (3), (5), (7), (8) and (11), it is preferable that the heat sink is integrally provided on the head of a bolt fastened to the terminal portion of the first heat generating component. This is because, when a bolt for fastening, for example, a current-carrying bus bar or the like is fastened to the terminal portion of the first heat generating component, by integrally providing the heat sink on the bolt, the number of parts and the number of work steps can be reduced.

[0023] The arrangement structure of the circuit unit according to the present disclosure is as follows: (13) A pair of circuit units according to any one of (1) to (12) above are arranged inside the battery pack as a positive pole circuit unit and a negative pole circuit unit, the air intake hole of the positive pole circuit unit and the air intake hole of the negative pole circuit unit are arranged in a central region of the inside of the battery pack, separated from each other by an air intake gap, and the exhaust hole of the positive pole circuit unit and the exhaust hole of the negative pole circuit unit are arranged in a peripheral region of the inside of the battery pack.

[0024] According to the circuit unit arrangement structure of this aspect, when a pair of circuit units each equipped with a fan motor is used for the positive and negative poles, smooth intake of air is ensured inside the battery pack, while exhaust air heated by the heat-generating components is exhausted to the peripheral area and is sufficiently cooled before moving to the center and being taken in again, thereby ensuring the stability of the operation of the circuit unit equipped with the fan motor housed in the battery pack.

[0025] The present disclosure can also be considered as another aspect below that can improve the heat dissipation performance of a circuit unit. For example, each of the above embodiments (6), (7), (8), (9), and (10) does not necessarily have to include the exhaust direction regulating portion of embodiment (1), and can be adopted in combination with a circuit unit including a circuit configuration portion including a heat-generating component, a fan motor, a case that houses the circuit configuration portion and the fan motor, an intake hole provided on the upstream side of the case in the air blowing direction of the fan motor, and an exhaust hole provided on the downstream side of the case in the air blowing direction of the fan motor, thereby improving the heat dissipation properties of the circuit unit.

[0026] <Details of the embodiment of the present disclosure> Specific examples of the circuit unit and the layout structure 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, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0027] <Embodiment 1> Hereinafter, the circuit unit 10 and the circuit unit arrangement structure 11 of the first embodiment of the present disclosure will be described with reference to Figs. 1 to 14. The circuit unit 10 is mounted inside a battery pack 12 in an electric vehicle or a hybrid vehicle, and suppresses the battery module 16 in the battery pack 12 from being adversely affected by the heat-generating components 14 provided inside the circuit unit 10. In particular, in the first embodiment, a pair of circuit units 10, 10 (a positive-electrode circuit unit 10a and a negative-electrode circuit unit 10b described later) are arranged in the battery pack 12 with a specific circuit unit arrangement structure 11. Note that the battery pack 12 can be arranged in any direction in the vehicle, but in the following, the upper side will be described as the front side in the direction perpendicular to the paper surface in Fig. 2 (upper side in Fig. 6), the lower side as the rear side in the direction perpendicular to the paper surface in Fig. 2 (lower side in Fig. 6), the left side as the left side in Fig. 2, the right side as the right side in Fig. 2, the front side as the lower side in Fig. 2, and the rear side as the upper side in Fig. 2. In addition, in the case of multiple identical components, reference numerals may be given to only some of the components and the reference numerals may be omitted for the other components.

[0028] <Battery pack 12> The battery pack 12 is configured by housing a battery module 16 including a plurality of battery cells (single cells) 18 in a housing 20. In the first embodiment, each battery cell 18 has a substantially rectangular parallelepiped shape and is arranged in a direction in which the left-right dimension is larger than the front-rear dimension. The battery cells 18 are arranged in parallel at a predetermined distance in the front-rear and left-right directions, and these battery cells 18 are electrically connected, for example, by a bus bar module (not shown) extending in the front-rear direction. The battery cells 18 may be electrically connected in series or in parallel by the bus bar module. The battery modules 16 are configured by connecting the battery cells 18 by the bus bar module.

[0029] At least one of the battery cells 18 is provided on the upper surface with a BMS (Battery Management System). A BMS board 22 is placed in a state housed in a case. This BMS board 22 is electrically connected via wires (not shown) to a bus bar module that electrically connects each battery cell 18. A known BMS board 22 may be used as the BMS board 22, and has a function of, for example, eliminating voltage differences between the battery cells 18 connected in series within the battery module 16 to adjust the balance, and measuring the voltage, current, temperature, etc. of each battery cell 18 to monitor for the presence or absence of abnormalities.

[0030] The housing 20 has a hollow rectangular box shape as a whole, and is composed of a housing body 24 that opens upward, and a lid 28 that covers an upper opening 26 of the housing body 24. The housing 20 is made of metal, for example, aluminum or an aluminum alloy. The method of fixing the housing body 24 and the lid 28 is not limited, but they are fixed by bolts, screws, or the like. In the first embodiment, when the battery module 16 is accommodated in the housing body 24, a gap is provided between the battery module 16 and the front wall of the housing body 24, and the circuit unit 10 is mounted between the battery module 16 and the front wall of the housing body 24.

[0031] In particular, in the first embodiment, an exhaust direction restricting portion 40 of the circuit unit 10, which will be described later, is formed integrally with the housing body 24, and is formed to protrude inward in the left-right direction from the wall portions on both the left and right sides of the housing body 24. The exhaust direction restricting portion 40 has a triangular shape in a plan view (viewed in the up-down direction), and the front end surface is configured as an inclined surface 42 that is inclined with respect to the left-right direction and the front-rear direction.

[0032] <Circuit unit 10> The circuit unit 10 includes a circuit unit body 29. The circuit unit body 29 includes a circuit configuration section 30 including the heat generating component 14, a fan motor 32, and a case 34 that houses the circuit configuration section 30 and the fan motor 32. In addition, an intake hole 36 is provided on the upstream side of the fan motor 32 in the air blowing direction in the case 34, and an exhaust hole 38 is provided on the downstream side of the fan motor 32 in the air blowing direction. Furthermore, the circuit unit 10 includes an exhaust direction regulating section 40 that directs the exhaust air from the exhaust hole 38 in a direction away from the battery module 16. As described above, in the first embodiment, the exhaust direction regulating section 40 is formed integrally with the housing body 24 in the battery pack 12, and is formed as a separate body from the circuit unit body 29. In short, in the first embodiment, the circuit unit 10 includes the circuit unit body 29 and the exhaust direction regulating section 40.

[0033] In particular, in the first embodiment, a pair of circuit units 10, 10 is provided, including a positive circuit unit 10a electrically connected to the positive electrode of the battery module 16 (bus bar module connecting each battery cell 18) via an electric wire or the like (not shown), and a negative circuit unit 10b electrically connected to the negative electrode of the battery module 16 (bus bar module connecting each battery cell 18) via an electric wire or the like (not shown). The positive circuit unit 10a is provided on the left side of the battery pack 12, and the negative circuit unit 10b is provided on the right side of the battery pack 12.

[0034] The positive circuit unit 10a includes a positive main body 29a and a positive restriction portion 40a, while the negative circuit unit 10b includes a negative main body 29b and a negative restriction portion 40b. The positive restriction portion 40a is provided on the left wall of the housing main body 24, while the negative restriction portion 40b is provided on the right wall of the housing main body 24. The positive main body 29a and the negative main body 29b are each rectangular parallelepiped-shaped and are disposed inside the housing main body 24 so as to extend in the left-right direction.

[0035] <Positive pole circuit unit 10a> The positive pole main body 29a constituting the positive pole circuit unit 10a is shown in Fig. 3 to Fig. 9. The positive pole main body 29a includes a positive pole circuit configuration section 30a, a positive pole fan motor 32a, and a positive pole case 34a. The positive pole circuit configuration section 30a includes a heat generating component 14, which includes a relay 44 as a first heat generating component and a fuse 46 as a second heat generating component.

[0036] <Heat generating component 14 (relay 44 and fuse 46)> In the first embodiment, the first heat generating component is a relay 44, and two relays 44, 44 are provided at a distance from each other in the left-right direction in the left part of the positive pole main body 29a. Each relay 44 has a case body 48 in the shape of a substantially hollow rectangular box, and a pair of terminals 50, 50 are exposed from the case body 48 at the front side of each relay 44 (the front side of the right relay 44, and the rear side of the left relay 44) at a distance from each other in the left-right direction. In addition, an insulating partition plate 52 is provided around each terminal 50 on the surface of the case body 48, specifically between each terminal 50 in the left-right direction, to separate each terminal 50. Each insulating partition plate 52 protrudes from each terminal 50 to the front side of each relay 44 with a protruding height A (see FIG. 7). In addition, a coil 54 shown by a two-dot chain line in FIGS. 7 and 9 is accommodated in the case body 48 of each relay 44.

[0037] A heat sink 56 is thermally connected to each terminal portion 50 of each relay 44. In the first embodiment, two heat sinks 56, 56 are provided continuously in the left-right direction. As shown in FIG. 5, each heat sink 56 is substantially rectangular in plan view, and each heat sink 56 has a plate-shaped portion 58 extending in the horizontal direction (direction perpendicular to the up-down direction) at its lower end. Each heat sink 56 has a plurality of heat sinks 60 protruding upward from the plate-shaped portion 58, and each heat sink 60 is arranged in parallel and spaced apart from each other in the front-rear direction, and extends in the left-right direction. As a result, a gap 62 extending in the left-right direction is provided between each heat sink 60 in the front-rear direction. In the first embodiment, the front-rear dimension of each gap 62 is substantially equal, and the front-rear dimension of each gap 62 is B (see FIG. 7).

[0038] The front-to-rear width of each heat sink 56 is larger than the front-to-rear width of the positive pole fan motor 32a, and the positive pole fan motor 32a and the heat sink 56 are connected by an exhaust duct 92, which will be described later. The front-to-rear width of the exhaust duct 92 increases toward the left, and the right end of the exhaust duct 92 has a front-to-rear width dimension that is approximately equal to that of the positive pole fan motor 32a, while the left end of the exhaust duct 92 has a front-to-rear width dimension that is approximately equal to that of the heat sink 56. This allows the air blown from the positive pole fan motor 32a to affect the entire front-to-rear direction of each heat sink 56.

[0039] 7, current-carrying bus bars 72d-72g (described later) constituting the positive-pole circuit configuration unit 30a are connected to the terminal portion 50 of each relay 44 by bolts 64. These current-carrying bus bars 72d-72g extend upward from the fixed portions with the respective terminal portions 50, and then bend inward in the front-rear direction to cover the upper portions of the respective relays 44. Each heat sink 56 is fixed to a portion 72a of the current-carrying bus bars 72d-72g covering the upper portions of the respective relays 44 via an insulating heat-conductive sheet 66.

[0040] Each insulating heat conductive sheet 66 is a sheet-like member having electrical insulation and good thermal conductivity, and a known one may be used. Each insulating heat conductive sheet 66 may be, for example, grease-like or gel-like, and may be applied to a predetermined position and then cured by heat or light (ultraviolet rays). The portion 72a of each of the current-carrying bus bars 72d to 72g covering the upper part of each of the relays 44 and the heat sink 56 may be fixed with an adhesive or bolts through each of the insulating heat conductive sheets 66, or both an adhesive and bolts may be used. As a result, each of the relays 44 and each of the heat sinks 56 are fixed through each of the current-carrying bus bars 72d to 72g and each of the insulating heat conductive sheets 66, and each of the heat sinks 56 is thermally connected to each of the terminal parts 50.

[0041] In the first embodiment, the second heat generating component is the fuse 46, which is provided in front of the right part of the positive pole main body 29a. A precharge relay 68 and a precharge resistor 70 are provided in the rear of the right part of the positive pole main body 29a. The fuse 46 generates less heat when energized than the relays 44, that is, the second heat generating component (the fuse 46) generates less heat than the first heat generating component (the relays 44). The second heat generating component may include the precharge relay 68 and the precharge resistor 70 in addition to the fuse 46. Since the precharge relay 68 and the precharge resistor 70 generate relatively less heat when energized, even if the precharge relay 68 and the precharge resistor 70 are included as the second heat generating component, the heat generating component of each of the second heat generating components is smaller than that of the first heat generating component.

[0042] <Circuit configuration unit 30 (positive pole circuit configuration unit 30a)> The relays 44 and the fuses 46 are electrically connected by a plurality of current-carrying bus bars 72. That is, the current-carrying bus bars 72 are overlapped with a pair of terminals 74, 74 of the fuse 46 and with the terminals 50 of the relays 44, and are fixed by bolts 76 (one of which is shown in FIG. 6). Specifically, the current-carrying bus bar 72b is fixed to the right terminal 74 of the fuse 46, and the left terminal 74 of the fuse 46 and the right terminal 50 of the right relay 44 are connected by current-carrying bus bars 72c, 72d. The left terminal 50 of the right relay 44 and the right terminal 50 of the left relay 44 are connected by the current-carrying bus bar 72e, and the current-carrying bus bar 72f is fixed to the left terminal 50 of the left relay 44. Further, a current supply bus bar 72g, which is separate from current supply bus bar 72e, is overlapped and fixed to the left terminal portion 50 of the right relay 44 and extends to the left.

[0043] As a result, an external connection portion 78 is formed by the end of the current-carrying busbar 72b at the right end of the positive pole body 29a, and an external connection portion 80 is formed by the ends of the current-carrying busbars 72f, 72g at the left end of the positive pole body 29a. Terminal portions provided at the ends of external electric wires (not shown) are overlapped with these external connection portions 78, 80 and fixed with bolts or the like, so that each of the current-carrying busbars 72b to 72g and each of the relays 44 and fuses 46 are electrically connected to the external electric wires. Although not limited thereto, for example, the external connection portion 78 is connected to the battery module 16 (particularly the busbar module) to serve as a connection portion for inputting electric power to the positive pole body 29a, and each of the external connection portions 80 is connected to an external electric device to serve as a connection portion for outputting electric power to the external electric device.

[0044] The pre-charge relay 68 and the pre-charge resistor 70 are, for example, electrically connected in series to configure a pre-charge circuit that bypasses the right-side relay 44 by means of an electric wire or the like (not shown). That is, the terminal portions of the pre-charge relay 68 and the pre-charge resistor 70 on the side opposite to the side where they are connected to each other are connected, for example, to the current-carrying bus bars 72d, 72e by means of an electric wire or the like.

[0045] In embodiment 1, the positive pole circuit component 30a in the positive pole main body 29a is configured to include each relay 44 which is a first heat-generating component, a fuse 46 which is a second heat-generating component, a pre-charge relay 68, a pre-charge resistor 70 and each current-carrying bus bar 72b to 72g.

[0046] In particular, in the first embodiment, a plurality of heat dissipation busbars 82 are fixed at the fixing points between the terminals 74 of the fuse 46 and the current-carrying busbars 72b, 72c, and at the fixing points between the terminals 50 of the relays 44 and the current-carrying busbars 72d to 72g. Each heat dissipation busbar 82 is substantially L-shaped and has a heat dissipation portion 84 that spreads in the horizontal direction and a portion that protrudes upward from each heat dissipation portion 84. The upward protruding portion of each heat dissipation busbar 82 is fastened together with each current-carrying busbar 72b to 72g to each terminal 74 of the fuse 46 and each terminal 50 of each relay 44 by bolts 76, 64. When assembling the positive pole main body 29a, the heat dissipation portion 84 of each heat dissipation busbar 82 is overlapped with a positive pole lower case 100 (described later) constituting the case 34 (positive pole case 34a) via an insulating heat-conductive sheet 86. The insulating heat conductive sheet 86 may be the same as the insulating heat conductive sheet 66 described above.

[0047] <Fan motor 32 (positive pole fan motor 32a)> A known fan motor may be used as the positive pole fan motor 32a, and an internally provided blade portion (not shown) rotates around a central axis L to generate an airflow from one axial direction of the positive pole fan motor 32a to the other. In the first embodiment, an airflow is generated from the right to the left in the positive pole main body 29a. The airflow (airflow direction α) generated by the positive pole fan motor 32a in the positive pole main body 29a is shown by a two-dot chain line in FIG. 2. As shown in FIG. 5, the central axis L of the positive pole fan motor 32a is located at the center of the front-rear direction of each heat sink 56 in a plan view.

[0048] In the first embodiment, the positive pole fan motor 32a is provided between the first heat generating components (relays 44) and the second heat generating components (fuse 46, precharge relay 68, and precharge resistor 70) in the positive pole main body 29a. That is, the first heat generating components (relays 44) are provided on the left side of the positive pole fan motor 32a, and the second heat generating components (fuse 46, precharge relay 68, and precharge resistor 70) are provided on the right side of the positive pole fan motor 32a. In short, in the first embodiment, the first heat generating components (relays 44) and the heat sinks 56 fixed above the relays 44 are disposed downstream of the positive pole fan motor 32a in the air blowing direction α. ​​Also, the second heat generating components (fuse 46, precharge relay 68, and precharge resistor 70) are disposed upstream of the positive pole fan motor 32a in the air blowing direction α.

[0049] Specifically, in the positive pole main body 29a, the space extending downstream from the positive pole fan motor 32a is an airflow path 88 (shown by a two-dot chain line in FIG. 7) where airflow is generated as the blades of the positive pole fan motor 32a rotate. Meanwhile, in the positive pole main body 29a, the space upstream of the positive pole fan motor 32a is a suction path 90 (shown by a two-dot chain line in FIG. 6) where airflow is generated in a direction in which air is sucked toward the positive pole fan motor 32a as air is blown by the positive pole fan motor 32a.

[0050] In particular, in the first embodiment, as shown in Fig. 4 and Fig. 8, the central axis L of the positive pole fan motor 32a is inclined with respect to the left-right direction, and is inclined upward as it goes leftward. In addition, an exhaust duct 92 is provided adjacent to the positive pole fan motor 32a on the downstream side (left side) of the airflow direction α, and the exhaust duct 92 is continuous with the heat sink 56 on the right. The exhaust duct 92 has a bottom wall portion that is continuous with the plate-shaped portion 58 of each heat sink 56, and a pair of side walls 94, 94 that are provided on both sides of the bottom wall portion in the front-rear direction and whose opposing distance in the front-rear direction gradually increases as it goes leftward. The opposing distance in the front-rear direction of each side wall portion 94 is approximately equal to that of the positive pole fan motor 32a at the right end, and is approximately equal to that of each heat sink 56 at the left end. As a result, the air blown by the positive pole fan motor 32a is applied to the entire front-to-rear direction of each heat sink 56 by the area surrounded by the exhaust duct 92 and the positive pole case 34a by the positive pole upper case 98 described later.

[0051] The above-mentioned airflow path 88 and suction path 90 are regions surrounded by the positive pole case 34a (a positive pole upper case 98 and a positive pole lower case 100 described later), for example. In the first embodiment, as described above, the central axis L of the positive pole fan motor 32a is inclined in an upward direction toward the left, and the space downstream of the positive pole fan motor 32a is partitioned in the vertical direction by the bottom wall of the exhaust duct 92 and the plate-like parts 58 of each heat sink 56. As a result, the airflow path 88 is formed by the space (the part above the bottom wall of the exhaust duct 92 and the plate-like parts 58 of each heat sink 56) in the upper part downstream of the positive pole fan motor 32a in the positive pole case 34a in particular. In addition, the lower space downstream of the positive pole fan motor 32a is connected to the upper space, and although the airflow speed is slower than in the upper part, the air in the upper part and the air in the lower part flow together, so that almost the entire space downstream of the positive pole fan motor 32a can be considered as the air supply path 88.

[0052] The positive pole fan motor 32a is fixed to a support frame 96, for example, by bolts, with a plurality of blades (not shown) housed in a case. The support frame 96 is fixed to a positive pole lower case 100 of the positive pole case 34a, described later, by bolts, so that the positive pole fan motor 32a is fixed to the positive pole circuit configuration unit 30a via the positive pole case 34a. The support frame 96 supporting the positive pole fan motor 32a and the exhaust duct 92 may be fixed to each other by known fixing means such as welding, adhesion, or concave-convex fitting. The exhaust duct 92 and the right heat sink 56 may be fixed to each other by known fixing means such as welding, adhesion, or concave-convex fitting.

[0053] <Case 34 (positive electrode case 34a)> The positive electrode case 34a is generally in the shape of a hollow rectangular parallelepiped and includes a positive electrode upper case 98 and a positive electrode lower case 100 which can be assembled and disassembled relative to each other in the vertical direction. The positive electrode upper case 98 and the positive electrode lower case 100 are formed of, for example, synthetic resin.

[0054] <Positive pole upper case 98> The positive pole upper case 98 is generally box-shaped and opens downward, and includes an upper bottom wall 102 and an upper peripheral wall 104 that protrudes downward from the outer periphery of the upper bottom wall 102. That is, the upper peripheral wall 104 includes an upper front wall 104a that constitutes the front wall, an upper rear wall 104b that constitutes the rear wall, an upper left wall 104c that constitutes the left wall, and an upper right wall 104d that constitutes the right wall. The positive pole upper case 98 is formed with a size that is larger in the left-right direction than in the front-rear direction. Note that the left part of the positive pole upper case 98 is larger in the up-down direction than the right part, so that the positive pole circuit component 30a, the positive pole fan motor 32a, the heat sinks 56, and the like are stably accommodated in the positive pole upper case 98.

[0055] As described above, the case 34 has an intake hole 36 on the upstream side of the airflow direction of the fan motor 32, and an exhaust hole 38 on the downstream side of the airflow direction of the fan motor 32. Therefore, in the positive pole case 34a, the positive pole intake hole 36a is provided on the right side, which is the upstream side of the airflow direction α of the positive pole fan motor 32a, and the positive pole exhaust hole 38a is provided on the left side, which is the downstream side of the airflow direction α of the positive pole fan motor 32a. In the first embodiment, these positive pole intake hole and exhaust hole 36a, 38a are both provided in the positive pole upper case 98. In addition, the suction path 90 in the positive pole case 34a communicates with the external space through the positive pole intake hole 36a, and the airflow path 88 in the positive pole case 34a communicates with the external space through the positive pole exhaust hole 38a.

[0056] In particular, in the first embodiment, the positive electrode air intake hole 36a is configured to include a plurality of air intake slits 106. The plurality of air intake slits 106 are formed in the right portions of the upper bottom wall portion 102, the upper front wall portion 104a, and the upper rear wall portion 104b, and in the upper right wall portion 104d, penetrating each wall portion in the plate thickness direction. The air intake slits 106 are aligned in the front-rear and / or left-right directions in each of these walls.

[0057] Similarly, in the first embodiment, the positive electrode exhaust hole 38a is configured to include a plurality of exhaust slits 108. Each of the plurality of exhaust slits 108 is formed in the left portions of the upper bottom wall portion 102, the upper front wall portion 104a, and the upper rear wall portion 104b, and in the upper left wall portion 104c, penetrating each wall portion in the plate thickness direction. Each of the exhaust slits 108 is provided in each of these walls aligned in the front-rear direction and / or the left-right direction.

[0058] The size of each of the intake slits 106 and each of the exhaust slits 108 is not limited, but it is preferable that the total cross-sectional area of ​​the intake slits 106 is equal to or larger than the axial cross-sectional area (cross-sectional area in a direction perpendicular to the central axis L) of the positive pole fan motor 32a. The total cross-sectional area of ​​the intake slits 106 refers to the total cross-sectional area in the thickness direction of each of the upper bottom wall 102, the upper front wall 104a, the upper rear wall 104b, and the upper right wall 104d in which the intake slits 106 are provided. Similarly, it is preferable that the total cross-sectional area of ​​the exhaust slits 108 is equal to or larger than the axial cross-sectional area of ​​the positive pole fan motor 32a. The total cross-sectional area of ​​the exhaust slits 108 refers to the total cross-sectional area in the thickness direction of each of the upper bottom wall 102, the upper front wall 104a, the upper rear wall 104b, and the upper left wall 104c in which the exhaust slits 108 are provided. Specifically, the opening width dimension C (see FIG. 7) of the exhaust slit 108 is preferably set to, for example, 3 mm or more. Similarly, the opening width dimension of the intake slit 106 is preferably set to, for example, 3 mm or more.

[0059] 7, it is preferable that at least one of the plurality of exhaust slits 108 is provided at approximately the same position in the front-rear direction as the gaps 62 between the heat sinks 60, 60 provided in each heat sink 56, and faces the gaps in the left-right direction. In the first embodiment, some of the plurality of exhaust slits 108 face some of the gaps 62 between the heat sinks 60, 60 in the left-right direction. Similarly, it is preferable that at least one of the plurality of intake slits 106 is provided at approximately the same position in the front-rear direction as the gaps 62 between the heat sinks 60, 60 provided in each heat sink 56.

[0060] In the first embodiment, a plurality of lock recesses 110 for engaging with lock protrusions 122 (described later) in the positive-electrode lower case 100 are provided at lower ends of the walls (upper front wall 104a, upper rear wall 104b, upper left wall 104c, and upper right wall 104d) constituting the upper peripheral wall 104, spaced apart from one another in the circumferential direction. Furthermore, in the positive-electrode case 34a, an electric wire insertion hole 112 through which an external electric wire connected to the external connection portion 78 is inserted is formed at a position corresponding to the external connection portion 78, and an electric wire insertion hole 114 through which an external electric wire connected to each external connection portion 80 is inserted is formed at a position corresponding to each external connection portion 80. In the first embodiment, an upper insertion hole 112a constituting the electric wire insertion hole 112 is formed in the right end portion of the upper rear wall portion 104b, and an upper insertion hole 114a constituting the electric wire insertion hole 114 is formed in the left end portions of the upper front wall portion 104a and the upper rear wall portion 104b. These upper insertion holes 112a, 114a constitute the electric wire insertion holes 112, 114 together with lower insertion holes 112b, 114b, which will be described later, provided in the positive-electrode lower case 100.

[0061] <Lower case 100 for positive pole> The positive pole lower case 100 is generally box-shaped and opens upward, and includes a bottom wall 116 and a lower peripheral wall 118 that protrudes upward from the outer periphery of the bottom wall 116. The positive pole lower case 100 is formed with a larger left-right dimension than a front-rear dimension. When the positive pole upper case 98 and the positive pole lower case 100 are assembled, the open end of the lower peripheral wall 118 and the open end of the upper peripheral wall 104 are butted against each other in the vertical direction, so that the upper opening of the lower peripheral wall 118 is covered by the positive pole upper case 98. The positive pole lower case 100 holds a plurality of nuts 120 in a substantially buried state. Each nut 120 is fastened by the aforementioned bolt 76, or a bolt (not shown) that is inserted through the support frame 96 that supports the positive pole fan motor 32a and each of the external connection parts 78, 80.

[0062] In the first embodiment, at the upper end of the lower peripheral wall portion 118, at positions corresponding to the lock recesses 110 in the positive pole upper case 98, lock protrusions 122 protruding outward are formed. Furthermore, at the positions corresponding to the external connection portions 78, lower insertion holes 112b constituting the electric wire insertion holes 112 are formed in the lower peripheral wall portion 118, and lower insertion holes 114b constituting the electric wire insertion holes 114 are formed in positions corresponding to the external connection portions 80. In the first embodiment, the lower insertion hole 112b is formed in the right end portion of the rear wall portion of the lower peripheral wall portion 118, and the lower insertion hole 114b is formed in the left end portions of the front and rear wall portions of the lower peripheral wall portion 118.

[0063] <Negative pole circuit unit 10b> The negative pole main body 29b constituting the negative pole circuit unit 10b is shown in Figs. 10 to 14. The negative pole main body 29b includes a negative pole circuit configuration section 30b, a negative pole fan motor 32b, and a negative pole case 34b. The basic structure of the negative pole main body 29b is similar to that of the positive pole main body 29a, and only a brief explanation of the negative pole main body 29b will be given. In the negative pole main body 29b, the same members and parts as those of the positive pole main body 29a are denoted in the figures with the same reference numerals as those of the positive pole main body 29a.

[0064] The negative-electrode circuit configuration section 30b also includes a relay 44 as a first heat-generating component and a fuse 46 as a second heat-generating component as the heat-generating component 14. In the first embodiment, two relays 44, 44 are provided at a distance from each other in the left-right direction in the right part of the negative-electrode main body 29b. Each relay 44 has a case body 48, and a pair of terminal parts 50, 50 is provided on the front side of each relay 44 (the front side of the right relay 44, and the rear side of the left relay 44). An insulating partition plate 52 is provided between each of the terminal parts 50 over the entire length of each relay 44 in the vertical direction. The case body 48 of each relay 44 houses a coil 54 shown by a two-dot chain line in FIG. 14.

[0065] Further, a heat sink 56 is thermally connected to each terminal portion 50 of each relay 44. The heat sinks 56 are provided at approximately the same position in the front-rear direction and are separated from each other in the left-right direction. The current-carrying bus bars 72d-72g are connected to each terminal portion 50 of each relay 44 by bolts 64, and each relay 44 and each heat sink 56 are fixed via each current-carrying bus bar 72d-72g and each insulating heat conductive sheet 66. As a result, heat generated by each relay 44 is transferred to each heat sink 56 via each current-carrying bus bar 72d-72g and each insulating heat conductive sheet 66.

[0066] A fuse 46 is provided in the left portion of the negative pole main body 29b. The fuse 46 in the negative pole main body 29b may be, for example, a pyro fuse. A monitoring and driving unit 124 is provided in the right portion of the negative pole main body 29b. The monitoring and driving unit 124 is configured by, for example, housing a board or the like on which a microcomputer or the like (not shown) is mounted in a case, and monitors the internal state of the negative pole main body 29b and drives the positive pole and negative pole fan motors 32a, 32b as necessary.

[0067] That is, in the first embodiment, the monitoring and driving unit 124 includes a temperature sensor (not shown) and is electrically connected to the positive pole fan motor 32a and the negative pole fan motor 32b via an electric wire (not shown). The monitoring and driving unit 124 monitors the temperature inside the negative pole main body 29b or the battery pack 12, and when the temperature exceeds a predetermined temperature, it transmits a driving signal to the positive pole fan motor 32a and the negative pole fan motor 32b to drive the positive pole and negative pole fan motors 32a and 32b. The monitoring and driving unit 124 may be configured to monitor, for example, a current flowing through the negative pole main body 29b, and may be configured to transmit a driving signal to the positive pole fan motor 32a and the negative pole fan motor 32b when a current larger than a predetermined value flows. Therefore, the monitoring and driving unit 124 may be electrically connected to, for example, the current busbar 72 (current busbars 72b to 72g) in the negative pole main body 29b.

[0068] Alternatively, the monitoring and driving unit 124 may be electrically connected to the aforementioned BMS board 22 provided in the battery pack 12, and when the BMS board 22 detects that the temperature or current (or voltage) in the battery pack 12 exceeds a predetermined value, the BMS board 22 may send a signal to the monitoring and driving unit 124 to drive the positive pole fan motor 32a and the negative pole fan motor 32b.

[0069] <Circuit configuration unit 30 (negative electrode circuit configuration unit 30b)> In the first embodiment, the negative pole circuit configuration section 30b in the negative pole main body 29b is configured to include the relays 44 which are the first heat generating components, the fuses 46 which are the second heat generating components, the current carrying bus bars 72b to 72g, and the monitoring and driving section 124. The heat dissipation bus bars 82 are fixed to the current carrying bus bars 72b to 72g by bolts 64, 76. The heat dissipation section 84 of each heat dissipation bus bar 82 is arranged to be superimposed on a negative pole lower case 128 (described later) which constitutes the case 34 (negative pole case 34b) via the insulating heat conductive sheets 86.

[0070] <Fan motor 32 (negative pole fan motor 32b)> The negative pole fan motor 32b may have the same shape as the positive pole fan motor 32a. In the first embodiment, an airflow from left to right is generated in the negative pole main body 29b by rotating a blade portion (not shown) of the negative pole fan motor 32b about a central axis M. The airflow (airflow direction β) generated by the negative pole fan motor 32b in the negative pole main body 29b is shown by a two-dot chain line in FIG. 11. As shown in FIG. 11, the central axis M of the negative pole fan motor 32b is located at the center of the front-rear direction of each heat sink 56 in a plan view.

[0071] The negative pole fan motor 32b is provided between the first heat generating component (relays 44) and the second heat generating component (fuse 46) in the negative pole main body 29b. That is, in the first embodiment, the first heat generating component (relays 44) and the heat sinks 56 fixed above the relays 44 are disposed downstream of the negative pole fan motor 32b in the airflow direction β. The second heat generating component (fuse 46) is disposed upstream of the negative pole fan motor 32b in the airflow direction β. In short, in the space in the right part of the negative pole main body 29b, an airflow path 88 is configured in which an airflow is generated with the rotation of the blades in the negative pole fan motor 32b. In addition, in the space in the left part of the negative pole main body 29b, a suction path 90 (shown by a two-dot chain line in FIG. 12) is configured in which an airflow is generated in a direction in which air is sucked toward the negative pole fan motor 32b.

[0072] In particular, in the first embodiment, as shown in FIG. 12, the negative pole fan motor 32b is provided in the vertical middle part of the negative pole main body 29b. Therefore, the air blown from the negative pole fan motor 32b is not only applied to the upper part of the negative pole main body 29b (for example, the area where the heat sinks 56 are arranged) but also to the lower part of the negative pole main body 29b (for example, the area where the relays 44 are arranged). Therefore, the air blowing path 88 is substantially the entire area surrounded by the negative pole case 34b (the negative pole upper case 126 and the negative pole lower case 128 described later) downstream of the negative pole fan motor 32b. Similarly, the suction path 90 is substantially the entire area surrounded by the negative pole case 34b upstream of the negative pole fan motor 32b. As a result, in the negative electrode main body 29b, the air blowing path 88 and the suction path 90 are formed with approximately the same cross-sectional area (cross-sectional area in a cross section perpendicular to the left-right direction), and air flows with approximately a constant cross-sectional area.

[0073] The negative pole fan motor 32b described above is fixed to a support frame 96, for example, by bolts, etc. The support frame 96 is then fixed to a negative pole upper case 126 (described later) of the negative pole case 34b, for example, by bolts, etc., so that the negative pole fan motor 32b is fixed to the negative pole circuit configuration unit 30b via the negative pole case 34b.

[0074] <Case 34 (negative electrode case 34b)> The negative electrode case 34b is generally in the shape of a hollow rectangular parallelepiped, and is configured to include a negative electrode upper case 126 and a negative electrode lower case 128 which can be assembled and disassembled relative to each other in the vertical direction. The negative electrode upper case 126 and the negative electrode lower case 128 are formed of, for example, synthetic resin.

[0075] <Negative pole upper case 126> The negative electrode upper case 126 has the same shape as the positive electrode upper case 98, and includes an upper bottom wall portion 102 and an upper peripheral wall portion 104 that protrudes downward from the outer periphery of the upper bottom wall portion 102. The upper peripheral wall portion 104 includes an upper front wall portion 104a, an upper rear wall portion 104b, an upper left wall portion 104c, and an upper right wall portion 104d.

[0076] In the negative pole case 34b, a negative pole intake hole 36b is provided on the left side, which is the upstream side of the airflow direction β of the negative pole fan motor 32b, and a negative pole exhaust hole 38b is provided on the right side, which is the downstream side of the airflow direction β of the negative pole fan motor 32b. In the first embodiment, these negative pole intake holes and exhaust holes 36b, 38b are all provided in the negative pole upper case 126. That is, the suction path 90 in the negative pole case 34b communicates with the external space through the negative pole intake hole 36b, and the airflow path 88 in the negative pole case 34b communicates with the external space through the negative pole exhaust hole 38b.

[0077] The negative electrode air intake hole 36b includes a plurality of air intake slits 106. The plurality of air intake slits 106 are formed at the left end of the upper bottom wall portion 102 and the upper left wall portion 104c, penetrating each wall portion in the plate thickness direction. The air intake slits 106 are provided in parallel at the left end of the negative electrode upper case 126 and spaced apart from each other in the front-rear direction.

[0078] Similarly, the negative electrode exhaust hole 38b is configured to include a plurality of exhaust slits 108. Each of these exhaust slits 108 is formed in the right end portion of the upper bottom wall portion 102 and the upper right wall portion 104d, penetrating each wall portion in the plate thickness direction. The exhaust slits 108 are provided in parallel at the right end portion of the negative electrode upper case 126 and spaced apart from each other in the front-rear direction.

[0079] The size of the negative electrode intake hole and exhaust hole 36b, 38b provided in the negative electrode upper case 126 is not limited, but may be formed to be the same size as the positive electrode intake hole and exhaust hole 36a, 38a provided in the positive electrode upper case 98. In addition, it is preferable that at least one of the multiple exhaust slits 108 is provided at approximately the same position in the front-rear direction as the gap 62 between the heat sinks 60, 60 provided in each heat sink 56, and faces the gap in the left-right direction. Similarly, it is preferable that at least one of the multiple intake slits 106 is provided at approximately the same position in the front-rear direction as the gap 62 between the heat sinks 60, 60 provided in each heat sink 56.

[0080] <Lower case for negative pole 128> The negative electrode lower case 128 has the same shape as the positive electrode lower case 100, and includes a bottom wall 116 and a lower peripheral wall 118 that protrudes upward from the outer peripheral edge of the bottom wall 116. The negative electrode upper case 126 and the negative electrode lower case 128 may be fixed to each other by a recessed and protruding engagement between a locking protrusion and a locking recess, as in the case of the positive electrode case 34a, or may be fixed to each other by other known fixing means. The negative electrode case 34b may be formed with an electric wire insertion hole through which an external electric wire (not shown) is inserted, as in the case of the positive electrode case 34a. This electric wire insertion hole may be provided in the negative electrode upper case 126, or may be provided across both the negative electrode upper case 126 and the negative electrode lower case 128.

[0081] <Circuit unit layout structure 11> As described above, the circuit units 10 (positive and negative circuit units 10a, 10b) are disposed in the front portion of the housing body 24. Specifically, as also shown in Fig. 2, the exhaust direction regulating portion 40 (positive and negative regulating portions 40a, 40b) described above is provided in the front portion of the housing body 24, and the circuit unit bodies 29 (positive and negative bodies 29a, 29b) are disposed between the exhaust direction regulating portions 40a, 40b and the front wall portion of the housing body 24.

[0082] The positive electrode main body 29a and the negative electrode main body 29b are arranged so that their respective air intakes 36 (positive electrode air intake 36a and negative electrode air intake 36b) face each other. The positive electrode air intake 36a in the positive electrode main body 29a and the negative electrode air intake 36b in the negative electrode main body 29b are separated from each other by an air intake gap 130 in the housing main body 24. The positive electrode and negative electrode air intakes 36a, 36b are each arranged in a central region 132 in the left-right direction inside the battery pack 12.

[0083] In contrast, the positive electrode main body 29a and the negative electrode main body 29b are arranged such that the respective exhaust holes 38 (positive electrode exhaust hole 38a and negative electrode exhaust hole 38b) face the wall portions on both the left and right sides of the housing main body 24. That is, the positive electrode and negative electrode exhaust holes 38a, 38b are respectively arranged in the left and right peripheral regions 134, 134 inside the battery pack 12. This constitutes the circuit unit arrangement structure 11 according to the present disclosure.

[0084] <Assembly of the circuit unit 10 (positive and negative circuit units 10a, 10b)> A specific example of a method for assembling the positive and negative circuit units 10a, 10b will be described below. Note that the method for assembling the positive and negative circuit units 10a, 10b is not limited to the embodiment described below.

[0085] First, a method of assembling the positive pole main body 29a in the positive pole circuit unit 10a will be described. First, the relays 44 and the fuses 46 are bolted to the positive pole lower case 100 together with the current-carrying bus bars 72b to 72g and the heat-dissipating bus bars 82. Note that the insulating heat-conducting sheets 86 are provided in advance on the upper surface of the bottom wall portion 116 of the positive pole lower case 100 and / or the lower surface of the heat-dissipating portion 84 of each heat-dissipating bus bar 82. The positive pole fan motor 32a and the exhaust duct 92 are fixed to each other, and the positive pole fan motor 32a and the exhaust duct 92 are bolted to the positive pole lower case 100. Furthermore, the heat sinks 56 are overlapped with the portions 72a of the current-carrying bus bars 72d to 72g that cover the relays 44 via the insulating heat-conducting sheets 66, and are fixed by bolts or the like. Thereafter, the pre-charge relay 68 and the pre-charge resistor 70 are electrically connected to a predetermined current-carrying bus bar 72 .

[0086] Next, a method of assembling the negative pole main body 29b in the negative pole circuit unit 10b will be described. First, the relays 44 and the fuses 46 are bolted to the negative pole lower case 128 together with the current-carrying bus bars 72b to 72g and the heat-dissipating bus bars 82. The insulating heat-conducting sheets 86 are provided in advance on the upper surface of the bottom wall portion 116 of the negative pole lower case 128 and / or the lower surface of the heat-dissipating portion 84 of the heat-dissipating bus bars 82. The heat sinks 56 are overlapped with the portions 72a of the current-carrying bus bars 72d to 72g that cover the relays 44 via the insulating heat-conducting sheets 66, and are fixed by bolts or the like. Meanwhile, the negative pole fan motor 32b is fixed to the negative pole upper case 126 via a support frame 96. Thereafter, the monitoring and driving unit 124 is housed in the negative pole lower case 128, and the monitoring and driving unit 124 is electrically connected to the positive pole and negative pole fan motors 32a, 32b.

[0087] Next, the positive upper case 98 is brought close from above to fix the positive upper case 98 and the positive lower case 100 together, completing the positive main body 29a. The negative upper case 126 is brought close from above to fix the negative upper case 126 and the negative lower case 128 together, completing the negative main body 29b. These positive and negative main bodies 29a, 29b are disposed between the positive and negative regulating parts 40a, 40b and the front wall of the housing main body 24 in the housing main body 24 in which the positive and negative regulating parts 40a, 40b are provided. As a result, the positive circuit unit 10a is completed by the positive main body 29a and the positive regulating part 40a, and the negative circuit unit 10b is completed by the negative main body 29b and the negative regulating part 40b.

[0088] In this manner, the battery pack 12 is configured by housing a plurality of battery cells 18 and a BMS board 22 in the housing main body 24 in which the positive and negative circuit units 10a, 10b are provided, and electrically connecting them. In this battery pack 12, for example, when the monitoring and driving unit 124 detects that the temperature inside the negative main body 29b exceeds a predetermined temperature, a fan driving signal is sent to the positive and negative fan motors 32a, 32b, and the positive and negative fan motors 32a, 32b are driven. Alternatively, for example, when the BMS board 22 detects that the temperature inside the battery pack 12 exceeds a predetermined temperature, a signal for driving the positive and negative fan motors 32a, 32b is sent to the positive and negative fan motors 32a, 32b via the monitoring and driving unit 124, and the positive and negative fan motors 32a, 32b are driven.

[0089] Here, for example, in the positive circuit unit 10a, when the positive fan motor 32a is driven, air is sucked in from the positive air intake 36a adjacent to the battery cell 18, and an airflow in the blowing direction α is generated, and the air is exhausted from the positive exhaust hole 38a. The air exhausted from the positive exhaust hole 38a is changed in direction by the inclined surface 42 of the positive restriction part 40a, and flows in a direction away from the battery cell 18 (forward). Then, the air changed in direction by the inclined surface 42 flows inward in the left-right direction (rightward) between the positive body 29a and the front wall of the housing body 24, and reaches the central region 132 in the left-right center. The air that reaches the central region 132 is sucked in again from the positive air intake 36a and circulates.

[0090] The positive circuit configuration section 30a in the positive main body 29a has the heat generating components 14, such as the relays 44 and fuses 46, and these components, which generate heat when current is applied, are cooled by the air blown by the positive fan motor 32a. On the other hand, the air passing through the positive main body 29a increases in temperature by contacting the relays 44 and fuses 46, but the air with the increased temperature is redirected by the inclined surface 42 in the positive restriction section 40a and flows in a direction away from the battery cells 18. This prevents the air warmed by the heat generating components 14 (such as the relays 44 and fuses 46) from flowing toward the battery module 16 (the battery cells 18) and adversely affecting the battery module 16. The air discharged from the positive exhaust hole 38a can also be cooled by contacting the wall of the housing main body 24 in the battery pack 12, and the air discharged from the positive exhaust hole 38a can be sucked in from the positive intake hole 36a at a lower temperature. This makes it possible to efficiently cool the heat generated in the heat generating component 14. The above-mentioned effect can be similarly achieved in the negative electrode circuit unit 10b.

[0091] The heat generating component 14 includes the relays 44 as first heat generating components, each having a heat sink 56 thermally connected to each terminal portion 50, and each relay 44 and each heat sink 56 are disposed downstream of each fan motor 32 (positive and negative fan motors 32a, 32b) in the air blowing directions α, β. This allows the heat generated at the terminal portions 50 of each relay 44, which generates a relatively large amount of heat, to be dissipated by the air blown from the positive and negative fan motors 32a, 32b, using the heat sinks 56.

[0092] The heat generating component 14 includes a fuse 46 (including a precharge relay 68 and a precharge resistor 70 as an embodiment) as a second heat generating component arranged upstream of each fan motor 32 (positive and negative fan motors 32a, 32b) in the air blowing directions α, β, and the heat generation amount of the fuse 46 (and the precharge relay 68 and the precharge resistor 70) is made smaller than the heat generation amount of each relay 44. That is, the air that has passed upstream of each fan motor 32a, 32b (suction path 90) flows downstream of each fan motor 32a, 32b (air blowing path 88), but the second heat generating component with a relatively small heat generation amount is arranged upstream of each fan motor 32a, 32b. Therefore, the temperature rise of the air due to the second heat generating component is suppressed to some extent upstream of each fan motor 32a, 32b, and the air with a relatively low temperature can be blown downstream of each fan motor 32a, 32b where the first heat generating component (relays 44) with a relatively large heat generation amount is arranged. This prevents relatively high-temperature air from being blown downstream of the fan motors 32a and 32b, and allows stable dissipation of heat from the relays 44, which generate a relatively large amount of heat.

[0093] In addition, in the first embodiment, in the negative pole main body 29b, the air flow path 88 downstream of the negative pole fan motor 32b has a substantially constant cross-sectional area in a direction perpendicular to the air flow direction β (direction perpendicular to the left-right direction). In particular, in the first embodiment, in the negative pole main body 29b, the suction path 90 upstream of the negative pole fan motor 32b and the air flow path 88 downstream of the negative pole fan motor 32b have a substantially constant cross-sectional area in a direction perpendicular to the air flow direction β. This allows air to flow with a substantially constant cross-sectional area throughout the entire negative pole main body 29b. As a result, the occurrence of parts in which the air flow is difficult in the negative pole main body 29b is suppressed, and for example, a local temperature rise can be avoided.

[0094] Each of the intake holes 36a, 36b of the cases 34a, 34b includes a plurality of intake slits 106 penetrating the respective cases 34a, 34b, and each of the exhaust holes 38a, 38b of the cases 34a, 34b includes a plurality of exhaust slits 108 penetrating the respective cases 34a, 34b. The total cross-sectional area of ​​the intake slits 106 is preferably equal to or larger than the cross-sectional area perpendicular to the axis of each of the fan motors 32a, 32b, and the total cross-sectional area of ​​the exhaust slits 108 is preferably equal to or larger than the cross-sectional area perpendicular to the axis of each of the fan motors 32a, 32b. This allows air in the external space of each of the circuit unit bodies 29a, 29b to be stably sucked in through each intake slit 106 and flow to each of the fan motors 32a, 32b, and allows air that has passed through each of the fan motors 32a, 32b to be stably exhausted to the external space through each exhaust slit 108.

[0095] Each heat sink 56 includes a plurality of heat sinks 60 arranged in parallel, and at least one exhaust slit 108 is arranged facing the gap 62 between each of the heat sinks 60, 60. This allows air that has passed through the gap 62 between each of the heat sinks 60, 60 to flow into the exhaust slit 108 without changing the airflow directions α, β, and the air that has passed through each of the heat sinks 56 can be stably exhausted through the exhaust slit 108 to the external space of each of the circuit unit bodies 29a, 29b.

[0096] A positive electrode circuit unit 10a and a negative electrode circuit unit 10b are disposed inside the battery pack 12, and the intake holes 36a, 36b of the circuit unit bodies 29a, 29b are disposed in a central region 132 inside the battery pack 12, separated from each other by an intake gap 130. Also, the exhaust holes 38a, 38b of the circuit unit bodies 29a, 29b are disposed in peripheral regions 134 inside the battery pack 12. According to this circuit unit arrangement structure 11, exhaust from the circuit unit bodies 29a, 29b can be stably realized, as compared with a case in which the exhaust holes 38a, 38b of the circuit unit bodies 29a, 29b are directed toward the center of the battery pack 12, for example. Furthermore, by arranging each exhaust hole 38a, 38b in each peripheral region 134 of the battery pack 12, the air discharged from each exhaust hole 38a, 38b can be brought into stable contact with the wall portion constituting the housing main body 24, and air at a lower temperature than the discharged air can be drawn in again from each intake hole 36a, 36b.

[0097] <Embodiment 2> Hereinafter, the circuit unit body constituting the circuit unit of the second embodiment of the present disclosure will be described with reference to Figs. 15 to 22. This circuit unit body is a positive pole body 140, and the circuit unit body (positive pole body 140) and the exhaust direction regulating part constitute the circuit unit (positive pole circuit unit) in the second embodiment. As the exhaust direction regulating part, a positive pole regulating part 40a similar to that in the first embodiment may be adopted. In addition, inside the battery pack 12, a negative pole circuit unit 10b similar to that in the first embodiment may be adopted. That is, in the second embodiment, the structure of the positive pole body constituting the positive pole circuit unit in the battery pack 12 in the first embodiment is different. Therefore, in the second embodiment, the structure of the positive pole body 140 that constitutes the positive pole circuit unit is mainly described, and the description of other parts in the battery pack 12 is omitted. In addition, in the positive pole body 140, the members and parts that are substantially the same as those in the first embodiment are given the same reference numerals in the drawings as those in the first embodiment, and detailed description is omitted.

[0098] The basic structure of the positive pole main body 140 is the same as that of the first embodiment, and includes a circuit configuration section (positive pole circuit configuration section 142) configured to include the heat generating component 14, a fan motor (positive pole fan motor 144), and a case (positive pole case 146) that houses the positive pole circuit configuration section 142 and the positive pole fan motor 144. The positive pole case 146 is provided with an intake hole (positive pole intake hole 148) provided upstream of the positive pole fan motor 144 in the airflow direction γ (see FIG. 18), and an exhaust hole (positive pole exhaust hole 150) provided downstream of the airflow direction γ.

[0099] In the second embodiment as well, the heat generating component 14 includes a first heat generating component and a second heat generating component, the first heat generating component being constituted by a relay 44, and the second heat generating component being constituted by a fuse 46. In particular, in the second embodiment, a pair of relays 44, 44 are stacked and spaced apart from each other in the vertical direction, and each of these relays 44 is provided in the left portion of the positive pole main body 140. The fuse 46 is provided in the front region in the right portion of the positive pole main body 140.

[0100] A heat sink 152 is thermally connected to each terminal portion 50 of each relay 44. In the second embodiment, a pair of relays 44, 44 are arranged with their front sides facing forward, and as shown in Figs. 16 and 21, one heat sink 152a is fixed to each left terminal portion 50 of each of the upper and lower relays 44 by each bolt 64. Also, one heat sink 152b, 152c is fixed to each right terminal portion 50 of each of the upper and lower relays 44 by each bolt 64. Each plate-shaped portion 58 of each heat sink 152a to 152c spreads in a direction perpendicular to the front-rear direction, and a plurality of heat sinks 60 protrude from each plate-shaped portion 58 to the front side, which is the side of each terminal portion 50 of each relay 44. Each of these heat sinks 60 extends in the left-right direction while being spaced apart from each other in the up-down direction. As a result, a gap 62 extending in the left-right direction is provided between each heat sink 60 in the up-down direction. As described above, the protruding height from each terminal portion 50 of the insulating partition plate 52 in each relay 44 is A, while the protruding height from each terminal portion 50 of each heat sink plate 60 is D (see Figure 20), and the protruding height D of each heat sink plate 60 from each terminal portion 50 is greater than the protruding height A of each insulating partition plate 52 from each terminal portion 50.

[0101] As described above, the fuse 46 is provided in the front region on the right side of the positive pole main body 140, and the pre-charge relay 68 and the pre-charge resistor 70 are provided in the rear region on the right side of the positive pole main body 140.

[0102] <Circuit configuration unit (positive pole circuit configuration unit 142)> The relays 44 and the fuse 46 are electrically connected by a plurality of current-carrying bus bars 154. Specifically, current-carrying bus bars 154a and 154b are fixed to the terminals 74 of the fuse 46 by bolts 76. As shown in FIG. 22, the current-carrying bus bar 154c is fixed to the right terminal 50 of the lower relay 44 together with the heat sink 152c by the bolts 64, and the current-carrying bus bar 154d is fixed to the right terminal 50 of the upper relay 44 together with the heat sink 152b by the bolts 64. Furthermore, the current-carrying bus bar 154e is fixed to the left terminals 50 of the upper and lower relays 44 together with the heat sink 152a by the bolts 64. The current-carrying bus bar 154b and the current-carrying bus bar 154c are electrically connected to each other.

[0103] As a result, an external connection portion 78 is formed by the end of the current-carrying bus bar 154a at the right end of the positive-electrode main body 140. Also, at the left end of the positive-electrode main body 140, external connection portions 80 are formed by the ends of the current-carrying bus bars 154d and 154e, respectively.

[0104] Therefore, in embodiment 2, the positive pole circuit component 142 in the positive pole main body 140 is configured to include each relay 44, which is the first heat-generating component, the fuse 46, which is the second heat-generating component, the pre-charge relay 68, the pre-charge resistor 70, and each of the current-carrying bus bars 154a to 154e.

[0105] In the second embodiment, a plurality of heat dissipation bus bars 82 are fastened together by bolts 76 at the fixing points between the terminals 74 of the fuse 46 and the current bus bars 154a, 154b and at the connection points between the current bus bars 154b, 154c. As shown in FIG. 22, the upper end of the current bus bar 154c and the lower end of the current bus bar 154d each have a heat dissipation portion 155 that protrudes forward. When the heat sinks 152b, 152c are fixed to the relays 44, the heat dissipation portions 155 are arranged at approximately equal intervals in the vertical direction with respect to the heat dissipation plates 60 of the heat sinks 152b, 152c, so that the heat dissipation effect is exerted not only by the heat sinks 152a to 152c but also by the heat dissipation portions 155.

[0106] <Partition 156> Here, the internal space of the positive pole case 146 is divided into front and rear sides by a partition plate 156. The partition plate 156 is a plate-shaped member extending in the left-right direction as a whole, and is made of metal or synthetic resin. This partition plate 156 is attached from above the above-mentioned positive pole circuit configuration part 142, and is provided across the current-carrying bus bar 154a and each heat dissipation bus bar 82. The partition plate 156 can be fixed to a later-described positive pole lower case 170 constituting the positive pole case 146, for example, by a bolt (not shown) or the like. By providing such a partition plate 156 inside the positive pole case 146, the pre-charge relay 68, the pre-charge resistor 70, etc. are located in the area behind the partition plate 156, and each relay 44, fuse 46, etc. are located in the area ahead of the partition plate 156. Although the partition plate 156 extends in the left-right direction overall, it has a crank-shaped portion bent in the front-to-rear direction on the left side, and gaps 158 of a predetermined size are formed between the partition plate 156 and each relay 44 and each heat sink 152b, 152c.

[0107] <Positive pole fan motor 144> In the internal space of the positive pole case 146, which is partitioned in the front-rear direction by the partition plate 156, the positive pole fan motor 144 is disposed in the front region. In the second embodiment, the positive pole fan motor 144 is provided at the right end of the positive pole case 146, and an unillustrated blade portion provided inside rotates around the central axis N, so that an airflow is generated from the right to the left in the positive pole main body 140. The airflow (airflow direction γ) generated by the positive pole fan motor 144 in the positive pole main body 140 is shown by a two-dot chain line in FIG. 18. In the second embodiment, the partition plate 156 is provided in the positive pole case 146 to partition the internal space into front and rear sides, and the positive pole fan motor 144 is provided in the region forward of the partition plate 156, so that the airflow by the positive pole fan motor 144 is applied to the region forward of the partition plate 156.

[0108] That is, in the second embodiment, the relays 44 as the first heat generating components and the fuse 46 as the second heat generating components are arranged downstream (left) of the positive pole fan motor 144 in the airflow direction γ, and are not arranged upstream (right). In short, an airflow path 160 extending from the positive pole fan motor 144 toward the downstream side in the airflow direction γ of the positive pole fan motor 144 is formed by a space in front of the partition plate 156, and the relays 44 as the first heat generating components and the fuse 46 as the second heat generating components are arranged in this airflow path 160. And, this airflow path 160 is configured to include, in addition to the positive pole case 146, the partition plate 156 arranged in the positive pole case 146 and partitioning the internal space of the positive pole case 146. In particular, in the airflow path 160, the fuse 46 with a relatively small amount of heat generation is arranged on the upstream side, and the relays 44 with a relatively large amount of heat generation are arranged on the downstream side.

[0109] More specifically, the airflow path 160 is a space through which the airflow generated by driving the positive pole fan motor 144 can pass through the positive pole main body 140 in the left-right direction. The opening 162 on the upstream side (right side) of the airflow path 160 has a size that surrounds the positive pole fan motor 144 when viewed in the left-right direction, and the opening 164 on the downstream side (left side) of the airflow path 160 has a size that surrounds each relay 44 and each heat sink 152a to 152c when viewed in the left-right direction. In particular, in the second embodiment, in the region of the airflow path 160 from the positive pole fan motor 144 to each heat sink 152b, 152c, the cross-sectional area of ​​the airflow path 160 in a direction perpendicular to the airflow direction γ (direction perpendicular to the left-right direction) is approximately constant, and the cross-sectional area of ​​the airflow path 160 is increased at the part where the partition plate 156 is bent in a crank shape.

[0110] Here, the air flowing downstream (leftward) from the positive pole fan motor 144 comes into contact with the heat sinks 152b, 152c and the relays 44, so that the direction of flow of the air changes in part of the air, and part of the air flows into the gap 158 between the partition plate 156 and the heat sinks 152b, 152c and the relays 44. The air that flows into this gap 158 flows between the relays 44 and the partition plate 156 so as to follow the surface of the case body 48 of each relay 44, inside which the coil 54 is housed. Therefore, in the second embodiment, the air blowing path 160 is configured to include a body cooling path 166 that blows air to the surface of the case body 48 of each relay 44.

[0111] Note that the crank-shaped bent portion of the partition plate 156 (i.e., the main body cooling path 166) is not essential, and the airflow path 160 may extend substantially straight in the left-right direction. In this case, for example, the case main body 48 of each relay 44 is positioned rearward of the partition plate 156, and the opening 164 on the downstream side (left side) of the airflow path 160 is formed to have a size that surrounds each of the heat sinks 152a to 152c when viewed in the left-right direction. Even with this configuration, the air blown from the positive pole fan motor 144 acts on each of the heat sinks 152a to 152c, so that a good heat dissipation effect is exhibited.

[0112] <Positive electrode case 146> The positive electrode case 146 of the second embodiment has the same shape as the positive electrode case 34a of the first embodiment, and includes a positive electrode upper case 168 and a positive electrode lower case 170. A positive electrode intake hole 148 is formed in the right part of the positive electrode upper case 168, and a positive electrode exhaust hole 150 is formed in the left part of the positive electrode lower case 170. The positive electrode intake hole 148 includes a plurality of intake slits 106, and these intake slits 106 are aligned in the front-rear direction and / or the left-right direction. The positive electrode exhaust hole 150 includes a plurality of exhaust slits 108, and these exhaust slits 108 are aligned in the front-rear direction and / or the left-right direction.

[0113] The positive pole main body 140 of embodiment 2 having the above-described structure is also combined with the positive pole regulating portion 40a provided in the housing main body 24 of the battery pack 12 to form a positive pole circuit unit, thereby achieving the same effects as in embodiment 1.

[0114] In particular, in the second embodiment, the relays 44 and fuses 46, which are the heat generating components 14, are arranged downstream of the positive pole fan motor 144 in the airflow direction γ, and are not arranged upstream of the positive pole fan motor 144 in the airflow direction γ. This prevents the air whose temperature has risen due to the heat generated by the heat generating components 14 from being applied to the positive pole fan motor 144. In addition, the air whose temperature has risen by passing through the heat generating components 14 is cooled by contacting the housing main body 24 while being discharged from the positive pole exhaust hole 150 and circulating to the positive pole intake hole 148, so that it is possible to stably prevent high-temperature air from being applied to the positive pole fan motor 144 and adversely affecting the operation of the positive pole fan motor 144. Furthermore, since the fuse 46, which generates a relatively small amount of heat, is arranged upstream in the airflow path 160, high-temperature air is not applied to the downstream side, and heat dissipation of the relays 44, which generate a relatively large amount of heat, can be stably achieved.

[0115] In each of the heat sinks 152a to 152c thermally connected to the terminal portion 50 of each relay 44, the protruding height D of each heat dissipation plate 60 from each terminal portion 50 is made larger than the protruding height A of each insulating partition plate 52 of each relay 44 from each terminal portion 50. This allows the air sent from the positive pole fan motor 144 to reach each heat dissipation plate 60 without being obstructed by each insulating partition plate 52, thereby preventing a decrease in heat dissipation efficiency.

[0116] The airflow path 160 is configured to include a partition plate 156 that is disposed within the positive pole case 146 and partitions the internal space of the positive pole case 146. As a result, the relays 44 and fuses 46 that generate a relatively large amount of heat are disposed within the airflow path 160, while the pre-charge relays 68 and pre-charge resistors 70 that generate a relatively small amount of heat are disposed outside the airflow path 160. As a result, the airflow from the positive pole fan motor 144 can be efficiently applied to the relays 44 and fuses 46, and heat dissipation from the relays 44 and fuses 46 that generate a relatively large amount of heat can be stably achieved.

[0117] An opening 162 on the upstream side of the airflow path 160 is large enough to surround the positive pole fan motor 144, and an opening 164 on the downstream side of the airflow path 160 is large enough to surround the heat sinks 152a to 152c and the relays 44. This prevents the air from passing through a narrow path when sucking in air through the positive pole intake hole 148 and discharging air through the positive pole exhaust hole 150, preventing restriction of air circulation.

[0118] The air blowing path 160 includes a body cooling path 166 that blows air to the surface of the case body 48 of each relay 44. This allows not only heat generated in the terminal portion 50 of each relay 44 but also heat generated in the coil 54 of each relay 44 to be efficiently dissipated, improving the heat dissipation efficiency of each relay 44.

[0119] <Embodiment 3> Hereinafter, the positive pole main body 180, which is a circuit unit main body constituting the circuit unit of the third embodiment of the present disclosure, will be described with reference to Figs. 23 and 24. In Fig. 23, the positive pole main body 180 is shown in a state in which the positive pole upper case 168 constituting the positive pole case 146 has been removed. The basic structure of the positive pole main body 180 in the third embodiment is similar to that of the positive pole main body 140 in the second embodiment. However, in the third embodiment, as shown in Fig. 24, the current-carrying bus bar 154e has heat dissipation portions 155, 155 protruding forward also at both vertical ends of the portion (the right portion of the current-carrying bus bar 154e) fixed to the terminal portion 50 of each relay 44.

[0120] In the second embodiment, one heat sink 152a is fixed to each of the left terminal portions 50 of each relay 44 via the current-carrying bus bar 154e by the bolts 64, but in the third embodiment, heat sinks 182a and 182b are fixed to each of the left terminal portions 50 of each relay 44 via the current-carrying bus bar 154e by the bolts 64. As a result, in the third embodiment, a total of four heat sinks 182a to 182d, including the heat sinks 182c and 182d that are overlapped and fixed to the current-carrying bus bars 154d and 154c, are thermally connected to each of the terminal portions 50 of each relay 44.

[0121] The positive pole main body 180 in the third embodiment differs from the positive pole main body 140 in the second embodiment only in the shape of the current-carrying busbar 154e and the number of heat sinks 182a-182d. Also in the third embodiment, the heat generated at each terminal portion 50 of each relay 44 is dissipated by each heat dissipation portion 155 of each current-carrying busbar 154c-154e in addition to each heat sink 182a-182d, so that the positive pole main body 180 in the third embodiment can achieve the same effect as in the second embodiment.

[0122] <Modification 1 of the third embodiment> Hereinafter, as a first modification of the third embodiment of the present disclosure, a positive pole main body 190 will be described with reference to Figs. 25 and 26. In this first modification, a heat sink is integrally provided on a head 194 of a bolt 192 for overlapping and fastening each of the current-carrying bus bars 154c to 154e and each of the heat sinks 184a to 184d to the terminal portion 50 of each relay 44. In other words, a plurality of protrusions 196 having a large surface area and functioning as a heat sink are provided protruding forward on the head 194 of the bolt 192. Each of the protrusions 196 extends in the same direction (left-right direction) as each of the heat sinks 60 of each of the heat sinks 184a to 184d, and is provided spaced apart from each other in the up-down direction.

[0123] In this way, the projections 196 provided on the heads 194 of the bolts 192 extend in the left-right direction, thereby preventing the air sent by the positive pole fan motor 144 from being hindered. Also, heat generated at the terminal portions 50 of the relays 44 can be dissipated not only by the heat sinks 184a-184d and the heat dissipation portions 155 of the current-carrying bus bars 154c-154e but also by the bolts 192 that secure them, improving the heat dissipation efficiency.

[0124] <Modification 2 of the third embodiment> Hereinafter, as a second modification of the third embodiment of the present disclosure, the positive pole body 200 will be described with reference to Figs. 27 and 28. In this second modification, each of the energizing busbars 202a, 202b, and 202c, which are overlapped with the terminal portion 50 of each relay 44 and fixed by the bolt 64, is provided with a wavy portion 204 in a part thereof. Specifically, for example, the energizing busbar 202a is fixed at both ends in the length direction (left and right direction) by a bolt, and these both ends in the length direction are provided with flat portions 206 that spread out flatly so that the fastening force of the bolt can be stably applied, and the wavy portion 204 is provided in a left and right intermediate portion outside the flat portions 206. In addition, the energizing busbar 202b is provided with the wavy portion 204 at the right end, and the energizing busbar 202c is provided with the wavy portion 204 at the left and right intermediate portion.

[0125] More specifically, the wavy portion 204 has a shape in which peaks 208 that convex in one direction in the plate thickness direction and valleys 210 that convex in the other direction in the plate thickness direction are alternately repeated and are continuous, and these peaks 208 and valleys 210 are connected by a smoothly curved surface. These peaks 208 and valleys 210 each extend in the left-right direction, which is the same direction as the airflow direction γ of the positive pole fan motor 144.

[0126] Each of the current-carrying bus bars 202a-202c is fixed to the terminal portion 50 of the corresponding relay 44 by a bolt 64, and is in thermal contact with the terminal portion 50 of the corresponding relay 44. Each of the current-carrying bus bars 202a-202c has a large surface area at each of the wavy portions 204, so that when the terminal portion 50 of each relay 44 generates heat, the air blown from the positive pole fan motor 144 acts on the wavy portions 204 of each of the current-carrying bus bars 202a-202c, and the heat generated at the terminal portion 50 of each relay 44 is efficiently dissipated. In particular, since the peak portions 208 and the valley portions 210 of each of the wavy portions 204 extend in the left-right direction, the air blown from the positive pole fan motor 144 is not hindered, and stable heat dissipation can be achieved. In the second modification, the heat sinks 152a to 152c, 182a to 182d described in the second and third embodiments, and the bolts 192 having heat sinks may be used in combination.

[0127] <Embodiment 4> Hereinafter, the circuit unit main body constituting the circuit unit of the fourth embodiment of the present disclosure will be described with reference to Fig. 29 to Fig. 32. This circuit unit main body is a positive pole main body 220, and its basic structure is similar to that of the positive pole main body 29a of the first embodiment, but the positive pole main body 220 of the fourth embodiment has a path branching portion 224 in the air blowing path 222. In the following description, the same reference numerals as those of the first embodiment are used in the drawings to denote substantially the same members and parts as those of the first embodiment, and detailed description thereof will be omitted.

[0128] The positive pole main body 220 includes a circuit configuration section (positive pole circuit configuration section 226) including the heat-generating component 14, a fan motor (positive pole fan motor 228), and a case (positive pole case 230) that houses the positive pole circuit configuration section 226 and the positive pole fan motor 228. The positive pole case 230 is provided with an intake hole (positive pole intake hole 232) provided upstream of the positive pole fan motor 228 in the airflow direction δ (see FIG. 30), and an exhaust hole (positive pole exhaust hole 234) provided downstream of the airflow direction δ.

[0129] In the fourth embodiment, a pair of relays 44, 44 are arranged at a distance from each other in the left-right direction on the left part of the positive pole main body 220, and a fuse 46, a pre-charge relay 68, and a pre-charge resistor 70 are arranged on the right part of the positive pole main body 220. These heat generating components 14 are electrically connected by a plurality of current carrying bus bars 236a to 236f. ​​Therefore, in the fourth embodiment, the positive pole circuit configuration unit 226 is configured including the relays 44, the fuse 46, the pre-charge relay 68, the pre-charge resistor 70, and the current carrying bus bars 236a to 236f. ​​The heat dissipation bus bars 238a to 238h are thermally connected to these current carrying bus bars 236a to 236f.

[0130] A positive pole fan motor 228 is disposed in the left-right central portion of the positive pole main body 220. The positive pole fan motor 228 generates an airflow from right to left by rotating a blade portion (not shown) provided inside about a central axis O. The airflow (airflow direction δ) generated by the positive pole fan motor 228 in the positive pole main body 220 is indicated by a two-dot chain line in FIG. 30. That is, in the internal space of the positive pole main body 220, the space downstream (left) of the positive pole fan motor 228 is the airflow path 222, and the space upstream (right) of the positive pole fan motor 228 is the suction path 240.

[0131] Here, the positive pole case 230 is configured to include a positive pole upper case 242 and a positive pole lower case 244, and the positive pole lower case 244 is provided with a path branching section 224 for branching the air flowing through the airflow path 222. Specifically, the positive pole lower case 244 is provided downstream (left) of the positive pole fan motor 228 with a pair of outer guide wall sections 246, 246 whose opposing dimensions (front-rear dimension) gradually increase toward the left, and a pair of inner guide wall sections 248, 248 extending approximately parallel to the outer guide wall sections 246 between the outer guide wall sections 246 in the front-rear direction. The inner guide wall sections 248, 248 are connected to each other at their right ends, and the path branching section 224 is configured at this connection portion. In other words, the air blown by the driving of the positive pole fan motor 228 collides with the path branching section 224, causing the air blown to branch to both the front and rear sides and flow downstream at both the front and rear ends of the positive pole case 230.

[0132] In the fourth embodiment, at least one of the current-carrying busbars 236c-236f arranged in the air blowing path 222 (i.e., downstream of the positive pole fan motor 228) is provided with a wavy portion 250, and at least one of the heat-dissipating busbars 238e-238h arranged in the air blowing path 222 is provided with a wavy portion 250. In particular, in the fourth embodiment, the current-carrying busbar 236f is provided with a wavy portion 250, and the heat-dissipating busbar 238g is provided with a wavy portion 250.

[0133] The wavy portion 250 of the current-carrying busbar 236f and the wavy portion 250 of the heat-dissipating busbar 238g are located on the airflow paths 222 that branch out on both sides in the front-rear direction. In the fourth embodiment, the wavy portion 250 of the current-carrying busbar 236f is located in the front portion of the positive electrode case 230, and the wavy portion 250 of the heat-dissipating busbar 238g is located in the rear portion of the positive electrode case 230. Each wavy portion 250 is configured by peak portions 252 that convex on one side in the plate thickness direction and valley portions 254 that convex on the other side in the plate thickness direction being alternately and repeatedly provided in succession in the up-down direction, and extends in the left-right direction with a predetermined length.

[0134] In this way, the positive pole main body 220 having the branched airflow path 222 can also achieve the same effects as those of the first embodiment. In particular, in the fourth embodiment, the current-carrying bus bar 236f and the heat-dissipating bus bar 238g each have a wavy portion 250, and the surface area of ​​these wavy portions 250 is increased, thereby improving the heat dissipation effect when air is blown by the positive pole fan motor 228. Also, in each wavy portion 250, the peaks 252 and valleys 254 extend in the left-right direction, which is the same direction as the airflow direction δ, thereby preventing the airflow from being obstructed.

[0135] <Modification> As specific examples of the present disclosure, the first to fourth embodiments and the first and second modified examples of the third embodiment have been described in detail above, but the present disclosure is not limited to these specific descriptions. Modifications, improvements, etc. within the scope of the present disclosure that can achieve the object of the present disclosure are included in the present disclosure. For example, the following modified examples of the embodiments are also included in the technical scope of the present disclosure.

[0136] (1) In the circuit unit main body constituting the circuit unit according to the present disclosure, a hinge opening / closing part that can be opened and closed may be provided in a part of the case, so that the fan motor provided in the circuit unit can be easily replaced. For example, as in the positive pole main body 260 shown in FIG. 33, in the positive pole main body 140 described in the second embodiment, a hinge opening / closing part 262 that can be opened and closed by rotating around an axis may be provided at the right end and front side of the positive pole upper case 168. The upper view in FIG. 33 shows the hinge opening / closing part 262 in an open state, and the lower view in FIG. 33 shows the hinge opening / closing part 262 in a closed state. As shown in the upper view in FIG. 33, by opening the hinge opening / closing part 262, the positive pole fan motor 144 can be easily replaced, and as shown in the lower view in FIG. 33, by closing the hinge opening / closing part 262, the intrusion of dust and the like into the positive pole main body 260 can be suppressed. This configuration may be applied to the first and fourth embodiments, and the hinged opening / closing portion may be provided in the left-right central portion of the case, so that the fan motor provided in the left-right central portion can be easily replaced.

[0137] (2) For example, in the first embodiment, the exhaust direction regulating portion 40 (positive and negative pole regulating portions 40a, 40b) are provided on both the left and right wall portions of the housing main body 24 of the battery pack 12 as separate bodies from the circuit unit main body 29 (positive and negative pole main bodies 29a, 29b), but the present invention is not limited to this embodiment. For example, the exhaust direction regulating portion 40 may be provided on the circuit unit main body 29 as in the circuit unit 270 (positive pole circuit unit 270a and negative pole circuit unit 270b) shown in FIG. 34, and may be formed integrally with the case 34, or may be formed separately and then fixed thereto. The same applies to the second to fourth embodiments and the first and second modifications of the third embodiment.

[0138] Alternatively, as in the circuit unit (positive pole circuit unit 280) shown in Fig. 35, the shape of the case (positive pole case 146) may be configured to control the direction of air blown from the fan motor 144 (regulate the exhaust direction). In particular, in this embodiment, a partition plate 282 provided inside the positive pole case 146 has an inclined portion 284 that inclines forward at the left end of the positive pole case 146. As a result, the air that comes into contact with the heat sinks 152b, 152c and the relays 44 and branches into the rear main body cooling path 166 as in the second embodiment is guided by the inclined portion 284 and flows in a direction toward the front as it moves leftward. That is, in this embodiment, the fan motor 144 blows air in the directions γ1 and γ2, ie, the air blowing direction γ1 (shown by a two-dot chain line in FIG. 35) which travels substantially straight from right to left, and the air blowing direction γ2 (shown by a two-dot chain line in FIG. 35) which branches off rearward at the middle of the air blowing direction γ1 and is guided forward along the inclined portion 284 at the left end. The air blown in these directions γ1 and γ2 join together at the left end of the positive pole case 146 and is exhausted overall forward (in the direction away from the battery cells 18 in the battery pack 12) through the positive pole exhaust hole 150. As a result, it is possible to prevent the air warmed by the heat-generating components 14 (relays 44 and fuses 46) from flowing toward the battery modules 16 (battery cells 18) and adversely affecting the battery modules 16. Therefore, in this embodiment, an exhaust direction regulating portion that directs exhaust air from the exhaust hole (positive electrode exhaust hole 150) in a direction away from the battery module 16 is configured by the inclined portion 284. In particular, in this embodiment, the positive electrode exhaust hole 150 is provided only in the front portion of the positive electrode upper case 168, so that exhaust air in a direction away from the battery module 16 is stably achieved.

[0139] In addition, when the case does not have a partition plate, a wall portion that inclines forward as it moves leftward may be provided at the left end portion of the case, for example, spanning the rear wall portion and the left wall portion, and the wall portion may constitute the exhaust direction regulating portion. Alternatively, the exhaust hole (each exhaust slit) may be opened with an inclination toward the front as it moves leftward, that is, the exhaust direction regulating portion may be constituted by these exhaust holes (each exhaust slit). When the above-mentioned structure is adopted, the exhaust direction regulating portion is constituted by the shape of the case (including the partition plate) and the exhaust hole, so that it is possible to avoid forming a separate exhaust direction regulating portion. In addition, even when the exhaust direction regulating portion is provided in the battery pack, it is not limited to the wall portions on both the left and right sides of the housing main body, and may be provided on the bottom wall portion or the lid body.

[0140] (3) In the above embodiment, the intake holes (positive electrode intake holes 36a, 148, 232 and negative electrode intake holes 36b) and exhaust holes (positive electrode exhaust holes 38a, 150, 234 and negative electrode exhaust holes 38b) are respectively configured by a plurality of intake slits 106 and exhaust slits 108, but this is not limited to the above embodiment. The intake holes and exhaust holes according to the present disclosure may be a single hole that penetrates the case in the thickness direction. In addition, these intake holes and exhaust holes are not limited to being provided in the upper case that constitutes the case, but may be provided in the lower case, or may be provided in both the upper case and the lower case.

[0141] (4) For example, in the first embodiment, bolt 192 having a heat sink described in the first modification of the third embodiment may be employed, or the current-carrying bus bars 72d to 72g connected to each relay 44 in the first embodiment may be formed with a wavy portion described in the second modification of the third embodiment or the fourth embodiment. That is, at least two of the first to fourth embodiments and the first and second modifications of the third embodiment may be combined and employed, if possible.

[0142] (5) In the fourth embodiment, the path branching portion 224 that branches the air flowing through the air supply path 222 is provided in the positive electrode lower case 244. However, the path branching portion may be provided in the upper case that constitutes the case, or may be provided in both the upper case and the lower case. [Explanation of symbols]

[0143] 10 Circuit unit (embodiment 1) 10a positive circuit unit 10b Negative circuit unit 11 Circuit unit layout structure 12 Battery pack 14 Heat generating parts 16 Battery Module 18 Battery Cells 20. Cabinet 22 BMS board 24 Main unit 26 Upper opening 28 Lid 29 Circuit unit body 29a Positive pole body 29b Negative pole body 30 Circuit component 30a Positive circuit component 30b Negative pole circuit component 32 Fan motor 32a positive pole fan motor 32b Negative pole fan motor 34 cases 34a positive pole case 34b Case for negative pole 36 Air Intake Hole 36a Positive electrode air intake 36b Negative electrode air intake 38 Exhaust Vent 38a Positive electrode exhaust hole 38b Negative electrode exhaust hole 40 Exhaust direction control part 40a Positive pole regulation part 40b Negative pole regulation part 42 Slope 44 Relay (first heat generating component) 46 Fuse (second heat generating component) 48 Case body 50 Terminal section 52 Insulating partition plate 54 Coil 56 Heat sink 58 Plate-shaped part 60 Heat sink 62 Gap 64 Volts 66 Insulating heat conductive sheet 68 Precharge relay (second heat generating component) 70 Precharge resistor (second heat generating component) 72 Current carrying busbar 72a The portion of the current-carrying busbar that covers the upper part of the relay 72b~72g Current carrying busbars 74 Terminal section 76 Volts 78,80 External connection part 82 Heat dissipation bus bar 84 Heat radiation part 86 Insulating heat conductive sheet 88 Air flow path 90 Suction Path 92 Exhaust Duct 94 Side wall 96 Support Frame 98 Positive pole upper case 100 Lower case for positive pole 102 Upper bottom wall 104 Upper peripheral wall 104a Upper front wall 104b Upper rear wall 104c Upper left wall 104d Upper right wall 106 Intake slit 108 Exhaust slit 110 Lock recess 112 Wire insertion hole 112a Upper insertion hole 112b Lower insertion hole 114 Wire insertion hole 114a Upper insertion hole 114b Lower insertion hole 116 Bottom wall 118 Lower peripheral wall 120 Nut 122 Lock protrusion 124 Monitoring and driving unit 126 Negative pole upper case 128 Lower case for negative pole 130 Intake gap 132 Central area 134 Periphery 140 Positive pole body (circuit unit body, embodiment 2) 142 Positive pole circuit component (circuit component) 144 Positive pole fan motor (fan motor) 146 Positive pole case (case) 148 Positive electrode air intake (air intake) 150 Positive electrode exhaust hole (exhaust hole) 152, 152a~152c Heat sink 154, 154a~154e Current-carrying bus bars 155 Heat radiation part 156 Partition 158 Gap 160 Air flow path 162 (Upstream side of air passage) opening 164 (Downstream air path) opening 166 Main body cooling path 168 Positive pole upper case 170 Lower case for positive pole 180 Positive pole body (circuit unit body, embodiment 3) 182a~182d Heat sink 190 Positive pole main body (circuit unit main body, modified example 1 of embodiment 3) 192 volts 194 Head 196 Protrusion 200 Positive pole main body (circuit unit main body, modified example 2 of embodiment 3) 202a~202c Current carrying busbars 204 Wavy part 206 Flat area 208 Yamabe 210 Valley 220 Positive pole body (circuit unit body, embodiment 4) 222 Air flow path 224 Route Branch 226 Positive pole circuit component (circuit component) 228 Positive pole fan motor (fan motor) 230 Positive pole case (case) 232 Positive electrode air intake (air intake) 234 Positive electrode exhaust hole (exhaust hole) 236a~236f Current-carrying busbars 238a~238h Heat dissipation busbar 240 Suction Path 242 Positive pole upper case 244 Lower case for positive pole 246 Outer guide wall section 248 Inner guide wall 250 Wave 252 Yamabe 254 Valley 260 Positive terminal body (Fig. 33) 262 Hinge opening and closing part 270 Circuit unit (Fig. 34) 270a Positive circuit unit 270b Negative circuit unit 280 Circuit unit (Fig. 35) 282 Partition 284 Inclined section (exhaust direction control section) L,M,N,O center axis α,β,γ,δ,γ1,γ2 Air blowing direction

Claims

1. A circuit unit mounted inside a battery pack in which a battery module is housed in a housing, A circuit configuration unit including a heat generating component; A fan motor; a case that houses the circuit configuration unit and the fan motor; an intake hole provided on an upstream side of the case in a direction of airflow from the fan motor; an exhaust hole provided on a downstream side of the case in the air blowing direction of the fan motor; an exhaust direction restricting portion that directs exhaust air from the exhaust hole in a direction away from the battery module; A circuit unit comprising:

2. the heat generating component includes a first heat generating component having a heat sink thermally connected to a terminal portion; The circuit unit according to claim 1 , wherein the first heat generating component and the heat sink are disposed downstream of the fan motor in the air blowing direction.

3. 3. The circuit unit according to claim 2, wherein the heat generating component includes a second heat generating component arranged upstream of the fan motor in the air blowing direction, and the amount of heat generated by the second heat generating component is smaller than the amount of heat generated by the first heat generating component.

4. 4. The circuit unit according to claim 1, wherein the heat generating component is disposed downstream of the fan motor in the air blowing direction, and is not disposed upstream of the fan motor.

5. 4. The circuit unit according to claim 2, wherein the first heat-generating component is a relay, the heat sink includes a plurality of heat sink plates protruding from the terminal portion side, and a protruding height of the heat sink plates from the terminal portion is greater than a protruding height of an insulating partition plate protruding from the terminal portion around the terminal portion of the relay.

6. an air flow path extending from the fan motor toward the downstream side in the air flow direction of the fan motor, The heat generating component is disposed within the air flow path, 4. The circuit unit according to claim 1, wherein the air passage includes a partition plate disposed within the case to partition an internal space of the case.

7. the upstream opening of the air flow path has a size sufficient to surround the fan motor, The circuit unit according to claim 6 when claim 2 or claim 3 is recited, wherein the downstream opening of the air flow path has a size sufficient to surround the heat sink or the first heat generating component including the heat sink.

8. an air flow path extending from the fan motor toward the downstream side in the air flow direction of the fan motor, The heat generating component is disposed within the air flow path, 4. The circuit unit according to claim 2, wherein a cross-sectional area of ​​said air flow path in a direction perpendicular to said air flow direction is constant in a region from said fan motor to said heat sink.

9. an air flow path extending from the fan motor toward the downstream side in the air flow direction of the fan motor; the heat generating component includes a relay having a coil housed in a case body, The circuit unit according to claim 1 , wherein the airflow path includes a body cooling path that blows air to a surface of the case body of the relay.

10. the air intake hole of the case includes a plurality of air intake slits penetrating the case, the exhaust hole of the case includes a plurality of exhaust slits penetrating the case, The total cross-sectional area of ​​the plurality of intake slits is equal to or greater than the cross-sectional area perpendicular to the axis of the fan motor, 4. The circuit unit according to claim 1, wherein a total cross-sectional area of ​​the plurality of exhaust slits is equal to or greater than a cross-sectional area perpendicular to the axis of the fan motor.

11. The heat sink includes a plurality of heat sink plates arranged in parallel, 11. The circuit unit according to claim 10 when claim 2 or 3 is recited, wherein at least one of the exhaust slits is disposed opposite a gap between the heat sinks.

12. 4. The circuit unit according to claim 2, wherein the heat sink is provided integrally with a head of a bolt fastened to the terminal portion of the first heat generating component.

13. a pair of the circuit units according to any one of claims 1 to 3 is disposed inside the battery pack as a positive electrode circuit unit and a negative electrode circuit unit, the air intake hole of the positive electrode circuit unit and the air intake hole of the negative electrode circuit unit are disposed in a central region of the interior of the battery pack and are spaced apart from each other with an air intake gap therebetween, A circuit unit arrangement structure, in which the exhaust hole of the positive electrode circuit unit and the exhaust hole of the negative electrode circuit unit are arranged in a peripheral region of the inside of the battery pack.

Images