Pair of circuit units

Abstract

Disclosed is a pair of circuit units accommodated inside a housing of a battery pack and capable of reducing component quantity and assembly workload.　In a pair of circuit units 10, each circuit unit 10a, 10b includes a circuit configuration part 34 and a case 36. One circuit unit 10a includes a first fan motor 38, a second fan motor 40, and a fan drive unit 42. The case 36a of the one circuit unit 10a has a first air intake hole 44, a first exhaust hole 46, a second air intake hole 48, and a second exhaust hole 50. A heating component 14 of the one circuit unit 10a is disposed downstream of the first fan motor 38 in a blowing direction α and upstream of the first exhaust hole 46 in said direction. The case 36b of the other circuit unit 10b has an other-side air intake hole 116 and an other-side exhaust hole 118. A heating component 14 of the other circuit unit 10b is disposed between the other-side air intake hole 116 and the other-side exhaust hole 118 in a blowing direction β.

Description

A pair of circuit units

[0001] The present disclosure relates to a pair of circuit units.

[0002] Patent Document 1 discloses a relay unit as a circuit unit mounted on a vehicle and arranged 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 using air blown by the fan motor to cool a heat-dissipating component fixed to the terminal of the relay, which is a heat-generating component.

[0003] Japanese Patent Application Laid-Open No. 2018-206601

[0004] In recent years, a battery pack, which is one of the power sources installed in a vehicle, may house a circuit unit equipped with a heat-generating component such as a relay, as exemplified in Patent Document 1. In such cases, at least two circuit units, one for a positive side and one for a negative side, are housed within the battery pack housing. The fan motor installed in each circuit unit is driven, for example, during rapid charging or when a current above a certain level flows. Therefore, it is necessary to route and assemble a wire harness, including electric wires for the fan motor's drive power supply and control signals, from a battery management system (BMS) or the like installed in the same battery pack to each circuit unit, resulting in an increase in the number of parts and assembly steps.

[0005] Therefore, a pair of circuit units housed in a battery pack housing is disclosed, which allows for a reduction in the number of parts and assembly steps.

[0006] The pair of circuit units of the present disclosure are a pair of circuit units housed in a housing of a battery pack, each of the circuit units including a circuit configuration section including a heat-generating component, and a case that houses the circuit configuration section, one of the pair of circuit units includes a first fan motor and a second fan motor, and a fan drive section that is provided in the circuit configuration section and drives the first fan motor and the second fan motor, and the case of the one circuit unit includes a first intake hole provided upstream of the first fan motor in the airflow direction, a first exhaust hole provided downstream of the first fan motor in the airflow direction, a second intake hole provided upstream of the second fan motor in the airflow direction, and a second exhaust hole provided in front of the second fan motor. and a second exhaust hole provided downstream in the air blowing direction, wherein the heat-generating component of one of the circuit units is arranged downstream of the first fan motor in the air blowing direction of the first fan motor and upstream of the first exhaust hole, the case of the other circuit unit is provided downstream in the air blowing direction of the second fan motor, and has a second intake hole through which air blown by the second fan motor passing through the second exhaust hole passes, and a second exhaust hole located downstream of the second intake hole in the air blowing direction of the second fan motor, and the heat-generating component of the other circuit unit is arranged between the other intake hole and the other exhaust hole in the air blowing direction of the second fan motor.

[0007] According to the pair of circuit units of the present disclosure, the number of parts and the number of assembly steps can be reduced and the circuit units can be accommodated within the housing of the battery pack.

[0008] FIG. 1 is a perspective view showing a battery pack including a pair of circuit units according to the first embodiment, with a cover that constitutes a housing removed. FIG. 2 is an enlarged plan view showing a main portion of the battery pack shown in FIG. 1. FIG. 3 is a perspective view showing one of the pair of circuit units according to the first embodiment, with an upper case that constitutes a case removed. FIG. 4 is a plan view of the circuit unit shown in FIG. 3. FIG. 5 is an enlarged longitudinal sectional view showing a V-V cross section in FIG. 4. FIG. 6 is an exploded perspective view of the circuit unit shown in FIG. 3. FIG. 7 is an exploded perspective view showing a circuit configuration part that constitutes the circuit unit shown in FIG. 3 in an exploded state. FIG. 8 is a perspective view showing the other of the pair of circuit units according to the first embodiment, with an upper case that constitutes a case removed. FIG. 9 is a plan view showing a pair of circuit units according to another aspect of the present disclosure housed in a battery pack, and corresponds to FIG. 2.

[0009] <Description of Embodiments of the Present Disclosure> First, embodiments of the present disclosure will be listed and described. A pair of circuit units of the present disclosure includes: (1) a pair of circuit units housed in a housing of a battery pack, each of the circuit units including a circuit configuration section including a heat-generating component and a case that houses the circuit configuration section, one of the pair of circuit units including a first fan motor and a second fan motor, and a fan drive section that is provided in the circuit configuration section and drives the first fan motor and the second fan motor, and the case of the one circuit unit includes a first intake hole provided upstream of the first fan motor in the airflow direction, a first exhaust hole provided downstream of the first fan motor in the airflow direction, a second intake hole provided upstream of the second fan motor in the airflow direction, and a second exhaust hole provided downstream of the second fan motor in the airflow direction. and a second exhaust hole provided downstream, wherein the heat-generating component of one of the circuit units is arranged downstream of the first fan motor in the air blowing direction of the first fan motor and upstream of the first exhaust hole, and the case of the other circuit unit is provided downstream of the air blowing direction of the second fan motor and has a second intake hole through which the air blown by the second fan motor passing through the second exhaust hole passes, and a second exhaust hole located downstream of the other intake hole in the air blowing direction of the second fan motor, and the heat-generating component of the other circuit unit is arranged between the other intake hole and the other exhaust hole in the air blowing direction of the second fan motor.

[0010] According to this aspect, when a pair of circuit units (e.g., one for a positive electrode and one for a negative electrode) housed in a battery pack housing each include heat-generating components and require fan motors for cooling the heat-generating components, a first fan motor, a second fan motor, and a fan drive unit can be integrated into one of the pair of circuit units, allowing a single fan drive unit to drive the two fan motors. This eliminates the need to route external wiring harnesses for the drive power sources of the first and second fan motors. Even if external signal lines for transmitting control signals that control the on / off state of the drive units need to be routed, it is sufficient to route the wires to only one of the circuit units. This reduces the number of wiring harnesses connected to the pair of circuit units housing the fan motors and the assembly process.

[0011] In particular, by mounting a first fan motor for cooling one circuit unit and a second fan motor for cooling the other circuit unit in one circuit unit, it is sufficient to route the wires connecting the fan drive unit and the first fan motor / second fan motor respectively inside the case, and there is no need to route them outside the case.This means that the wire harness connecting the pair of circuit units can be eliminated or reduced, reducing the wiring space for the pair of circuit units and further reducing the assembly process.

[0012] In addition, the heat-generating components of one of the circuit units can be cooled quickly by providing a first intake hole and a first exhaust hole in the case of the one of the circuit units on the upstream and downstream sides of the air blowing direction of the first fan motor, and by arranging the heat-generating components between the first fan motor and the first exhaust hole, the heat-generating components of one of the circuit units can be quickly cooled by the air blown by the first fan motor.

[0013] In addition, the cooling of the heat-generating components of the other circuit unit can be achieved by arranging a second-side intake hole, through which the air blown by the second fan motor passing through the second exhaust hole, downstream in the air blowing direction of the second fan motor, in the case of the other circuit unit, and a second-side exhaust hole further downstream than the second-side intake hole, and by arranging the electrical components (heat-generating components) between them, the heat-generating components of the other circuit unit can be quickly cooled by the air blown by the second fan motor.

[0014] (2) In the above (1), it is preferable that the circuit unit further includes a heat sink thermally connected to each of the heat-generating components, and each of the heat sinks is disposed downstream of the first fan motor or the second fan motor in the airflow direction. Heat generated by the heat-generating components is efficiently transferred to the heat sink, and heat dissipation from the heat sink is further promoted by utilizing the airflow from the fan motor. This advantageously improves the heat dissipation of the heat-generating components within the circuit unit.

[0015] (3) In the above (1) or (2), preferably, the second fan motor is disposed upstream of the first fan motor in the airflow direction of the first fan motor, with its intake side facing the first fan motor, an intake area is defined between the opposing surfaces of the first fan motor and the second fan motor, and a plurality of through holes are provided in the case of one of the circuit units in an area covering the intake area, and the first intake hole and the second intake hole are shared by the plurality of through holes. When the first fan motor and the second fan motor are mounted in one of the circuit units, the intake area of ​​the two fan motors can be shared, and the plurality of through holes provided through the case covering the intake area can also be shared to provide the first intake hole and the second intake hole. This allows two fan motors to be mounted in one of the circuit units in a space-efficient manner while suppressing the increase in size of one of the circuit units, which is a concern when mounting two fan motors.

[0016] (4) In any one of (1) to (3) above, it is preferable that the heat-generating component of the one circuit unit is disposed downstream of the first fan motor in the airflow direction and not upstream of the first fan motor. By disposing the heat-generating component downstream of the first fan motor and not upstream of it, it is possible to prevent a problem such as the temperature of the intake side of the first fan motor rising due to the heat-generating component and exceeding the upper operating temperature limit of the first fan motor.

[0017] <Details of the embodiment of the present disclosure> Specific examples of a pair of circuit units 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.

[0018] First Embodiment A pair of circuit units 10 according to a first embodiment of the present disclosure will be described below with reference to FIGS. 1 to 8 . The pair of circuit units 10 are housed within a battery pack 12 in an electric vehicle or a hybrid vehicle, and can prevent the battery modules 16 in the battery pack 12 from being adversely affected by heat generated by heat-generating components 14 provided within each of the circuit units 10 a and 10 b. In the first embodiment, one of the pair of circuit units 10 is a negative-electrode circuit unit 10 a, and the other of the pair of circuit units 10 is a positive-electrode circuit unit 10 b. The battery pack 12 can be positioned in any orientation within the vehicle. In the following description, the upper side will be referred to as the front side in the direction perpendicular to the plane of the page in FIG. 2 (upper side in FIG. 5 ), the lower side will be referred to as the rear side in the direction perpendicular to the plane of the page in FIG. 2 (lower side in FIG. 5 ), the left side will be referred to as the left side in FIG. 2 , the right side will be referred to as the right side in FIG. 2 , the front side will be referred to as the lower side in FIG. 2 , and the rear side will be referred to as the upper side in FIG. 2 . Furthermore, in the case of multiple identical components, reference numerals may be assigned to only some of the components, and the reference numerals may be omitted for the other components.

[0019] <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 such that the left-right dimension is greater 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 are electrically connected by, for example, 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 module 16 is configured by connecting the battery cells 18 by the bus bar module.

[0020] A BMS (Battery Management System) board 22 is housed in a case and placed on the top surface of at least one of the battery cells 18. This BMS board 22 is electrically connected via wires (not shown) to a bus bar module that electrically connects the battery cells 18. A known board may be used as the BMS board 22, and has functions such as eliminating voltage differences between the battery cells 18 connected in series within the battery module 16 to balance them, and measuring the voltage, current, temperature, etc. of each battery cell 18 to monitor for abnormalities.

[0021] The housing 20 has an overall hollow rectangular box shape and is composed of a housing main body 24 that opens upward and a lid 28 that covers an upper opening 26 of the housing main body 24. The housing 20 is made of metal, for example, aluminum or an aluminum alloy. The method of fastening the housing main body 24 and the lid 28 is not limited, but they are fastened together, for example, with bolts, screws, or the like. In the first embodiment, when the battery module 16 is housed in the housing main body 24, a gap is provided between the battery module 16 and the front wall of the housing main body 24, and the pair of circuit units 10 described above are mounted between the battery module 16 and the front wall of the housing main body 24.

[0022] In the first embodiment, the battery pack 12 is provided with exhaust direction restriction portions 30, 30 that restrict the direction of exhaust air that has passed through the first exhaust hole 46 and the other-side exhaust hole 118, which will be described later, in each of the circuit units 10a, 10b. In particular, in the first embodiment, each of these exhaust direction restriction portions 30 is formed integrally with the housing main body 24, and each exhaust direction restriction portion 30 is formed to protrude inward in the left-right direction from the wall portions on both the left and right sides of the housing main body 24. Each exhaust direction restriction portion 30 has a triangular shape in a plan view (viewed in the up-down direction), and its front end surface is configured as an inclined surface 32 that is inclined with respect to the left-right and front-rear directions.

[0023] <Each Circuit Unit (Negative Polarity Circuit Unit 10a and Positive Polarity Circuit Unit 10b)> As described above, the pair of circuit units 10 is composed of the negative polarity circuit unit 10a and the positive polarity circuit unit 10b. The negative polarity circuit unit 10a is 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 polarity circuit unit 10b is 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). The negative polarity circuit unit 10a is provided on the right side of the battery pack 12, and the positive polarity circuit unit 10b is provided on the left side of the battery pack 12.

[0024] The negative electrode circuit unit 10a and the positive electrode circuit unit 10b are each rectangular parallelepiped and are arranged extending in the left-right direction inside the housing main body 24. As will be described later, a first exhaust hole 46 is provided at the right end of the negative electrode circuit unit 10a, and a second exhaust hole 118 is provided at the left end of the positive electrode circuit unit 10b. Therefore, the negative electrode exhaust direction restricting portion 30a is provided on the right wall of the housing main body 24, and the positive electrode exhaust direction restricting portion 30b is provided on the left wall of the housing main body 24. Furthermore, the negative electrode circuit unit 10a has a longer length in the left-right direction than the positive electrode circuit unit 10b.

[0025] The structure common to each circuit unit 10a, 10b is that each circuit unit 10a, 10b has a circuit configuration section 34 (a circuit configuration section 34a for the negative pole and a circuit configuration section 34b for the positive pole) that includes a heat-generating component 14, and a case 36 (a case 36a for the negative pole and a case 36b for the positive pole) that houses each circuit configuration section 34a, 34b.

[0026] 3 to 7, the negative pole circuit unit 10a includes a first fan motor 38, a second fan motor 40, and a fan drive unit 42 that drives the first fan motor 38 and the second fan motor 40. The fan drive unit 42 is provided in the negative pole circuit configuration unit 34a.

[0027] The negative pole case 36a has a first air intake hole 44 provided upstream (to the left) in the airflow direction α (shown by the two-dot chain line in FIG. 2 ) of the first fan motor 38, and a first exhaust hole 46 provided downstream (to the right) in the airflow direction α of the first fan motor 38. The negative pole case 36a also has a second air intake hole 48 provided upstream (to the right) in the airflow direction β of the second fan motor 40, and a second exhaust hole 50 provided downstream (to the left) in the airflow direction β of the second fan motor 40.

[0028] The heat-generating component 14 in the negative-electrode circuit unit 10a is disposed downstream (to the right) of the first fan motor 38 and upstream (to the left) of the first exhaust hole 46 in the air blowing direction α of the first fan motor 38. That is, in the negative-electrode circuit unit 10a, the heat-generating component 14 is disposed between the first fan motor 38 and the first exhaust hole 46 in the left-right direction.

[0029] <Heat-generating component 14 (relay 52 and fuse 54)> The heat-generating component 14 in the negative-electrode circuit unit 10a includes a relay 52 as a first heat-generating component and a fuse 54 as a second heat-generating component. In the first embodiment, two relays 52 are provided spaced apart from each other in the left-right direction in the right portion of the negative-electrode circuit unit 10a. Each relay 52 includes a case body 56 having a generally hollow rectangular box shape. A pair of terminals 58 are exposed from the case body 56 on the front side of each relay 52 (the front side of the right relay 52 and the rear side of the left relay 52) and spaced apart from each other in the left-right direction. An insulating partition plate 60 is provided between the terminals 58 in each case body 56 to separate the terminals 58.

[0030] A heat sink 62 is thermally connected to each terminal portion 58 of each relay 52. ​​In the first embodiment, two heat sinks 62 are provided with a gap between them in the left-right direction. As shown in FIG. 4 , each heat sink 62 is generally rectangular in plan view, and has a plate-like portion 64 at its lower end that extends in the horizontal direction (a direction perpendicular to the up-down direction). Each heat sink 62 has a plurality of heat sink plates 66 that protrude upward from the plate-like portion 64. The heat sinks 66 are arranged in parallel and spaced apart from each other in the front-to-rear direction, extending in the left-to-right direction. As a result, a gap 68 extending in the left-to-right direction is provided between the heat sinks 66 in the front-to-rear direction.

[0031] 6 and 7, the negative-pole circuit component 34a is connected by bolts (not shown) to the terminal 58 of each relay 52. ​​The bus bars 72d to 72g extend upward from the locations where they are fixed to the terminals 58, and then bend inward in the front-to-rear direction to cover the top of each relay 52. ​​The heat sinks 62 are fixed to the bus bars 72d to 72g at their portions 72a that cover the top of each relay 52, via insulating thermally conductive sheets 70.

[0032] Each insulating thermally conductive sheet 70 is a sheet-like member having electrical insulation and good thermal conductivity, and known insulating thermally conductive sheets may be used. The insulating thermally conductive sheets 70 may be, for example, grease-like or gel-like, and may be applied to a predetermined location and then cured by heat, light (ultraviolet light), or the like. The portions 72a of the current-carrying bus bars 72d to 72g that cover the relays 52 and the heat sink 62 may be fixed via the insulating thermally conductive sheets 70 using adhesive, bolts, or both adhesive and bolts. This fixes the relays 52 and the heat sinks 62 via the current-carrying bus bars 72d to 72g and the insulating thermally conductive sheets 70, thermally connecting the heat sinks 62 to the terminals 58.

[0033] A fuse 54 is provided as a second heat-generating component on the rear side of the central portion of the negative-electrode circuit unit 10a in the left-right direction. The fuse 54 in the negative-electrode circuit unit 10a may be, for example, a pyroelectric fuse. The amount of heat generated by this fuse 54 when energized is smaller than that of each relay 52. ​​In other words, the amount of heat generated by the second heat-generating component (fuse 54) is smaller than that of the first heat-generating components (relays 52).

[0034] <Circuit Configuration Unit 34 (Negative Electrode Circuit Configuration Unit 34a)> The relays 52 and fuses 54 are electrically connected by a plurality of energizing bus bars 72. That is, the energizing bus bars 72 are overlapped with a pair of terminals 74, 74 of the fuse 54 and with each terminal 58 of each relay 52, and are fixed by bolts 76 (one is shown in FIG. 5 ). Specifically, an energizing bus bar 72b is fixed to the left terminal 74 of the fuse 54, and the right terminal 74 of the fuse 54 is connected to the left terminal 58 of the left relay 52 by energizing bus bars 72c, 72d. The right terminal 58 of the left relay 52 is connected to the left terminal 58 of the right relay 52 by an energizing bus bar 72e, and the right terminal 58 of the right relay 52 is connected to the right terminal 58 of the right relay 52 by an energizing bus bar 72f. Further, a separate current-carrying bus bar 72g, which is separate from the current-carrying bus bar 72e, is superimposed on and fixed to the right terminal portion 58 of the left relay 52, and extends out to the right.

[0035] As a result, an external connection portion 78 is formed by the end of the current-carrying bus bar 72b at the left end of the negative-electrode circuit unit 10a, and external connection portions 80 are formed by the ends of the current-carrying bus bars 72f, 72g at the right end of the negative-electrode circuit unit 10a. Terminal portions provided on the ends of external electric wires (not shown) are overlapped with these external connection portions 78, 80 and fixed with bolts or the like, thereby electrically connecting each of the current-carrying bus bars 72b to 72g and each of the relays 52 and fuses 54 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 bus bar module) to serve as a connection portion for inputting power to the negative-electrode circuit unit 10a, and each external connection portion 80 is connected to external electrical equipment to serve as a connection portion for outputting power to the external electrical equipment.

[0036] A fan drive unit 42 is provided in the left-right intermediate portion of the negative pole circuit unit 10a, specifically between the fuse 54 and the left relay 52. ​​The fan drive unit 42 is configured, for example, by housing a board or the like on which a microcomputer (not shown) or the like is mounted in a case, and receives a fan drive signal or the like to send a drive signal to the first and second fan motors 38, 40, thereby driving the first and second fan motors 38, 40. The fan drive unit 42 and the first and second fan motors 38, 40 are electrically connected by electric wires 82, 82, respectively.

[0037] In the first embodiment, the fan drive unit 42 also has a monitoring function of monitoring the internal state of the negative electrode circuit unit 10 a. The internal state of the negative electrode circuit unit 10 a monitored by the fan drive unit 42 is, for example, the internal temperature of the negative electrode circuit unit 10 a or the current flowing through the negative electrode circuit unit 10 a.

[0038] That is, the fan drive unit 42 may be provided with a temperature sensor (not shown), and the fan drive unit 42 may monitor the temperature in the negative electrode circuit unit 10a or the battery pack 12, and if the temperature exceeds a predetermined temperature, send a drive signal to the first fan motor 38 or the second fan motor 40 to drive the first and second fan motors 38, 40. Alternatively, if the fan drive unit 42 monitors the current flowing through the negative electrode circuit unit 10a, for example, the fan drive unit 42 may be provided with a current sensor (not shown), and if a current greater than a predetermined value is detected, send a drive signal to the first fan motor 38 or the second fan motor 40. Therefore, the fan drive unit 42 may be electrically connected to, for example, the current bus bar 72 (current bus bars 72b to 72g) in the negative electrode circuit unit 10a.

[0039] Alternatively, the fan drive unit 42 may be electrically connected to the aforementioned BMS board 22 provided within the battery pack 12, and when the BMS board 22 detects that the temperature or current (or voltage) within the battery pack 12 has exceeded a predetermined value, the BMS board 22 may send a signal to the fan drive unit 42 to drive the first fan motor 38 and the second fan motor 40.

[0040] Therefore, in embodiment 1, the negative pole circuit configuration section 34a in the negative pole circuit unit 10a is configured to include each relay 52, which is the first heat-generating component, the fuse 54, which is the second heat-generating component, the fan drive section 42, and each current-carrying bus bar 72b to 72g.

[0041] In particular, in the first embodiment, a plurality of heat dissipation bus bars 84 are fixed at the fixed locations between the terminals 74 of the fuse 54 and the current-carrying bus bars 72b, 72c, and at the fixed locations between the terminals 58 of the relays 52 and the current-carrying bus bars 72d to 72g. Each heat dissipation bus bar 84 is generally L-shaped and has a heat dissipation portion 86 that extends horizontally and a portion that protrudes upward from the heat dissipation portion 86. The upward-protruding portion of each heat dissipation bus bar 84 is fastened together with the current-carrying bus bars 72b to 72g to the terminals 74 of the fuse 54 and the terminals 58 of the relays 52 by bolts (e.g., bolts 76). When assembling the negative-electrode circuit unit 10a, the heat dissipation portion 86 of each heat dissipation bus bar 84 is overlapped with a negative-electrode lower case 92 (described later) that constitutes the case 36 (negative-electrode case 36a) via an insulating heat-conductive sheet 88. The insulating heat-conductive sheet 88 may be the same as the insulating heat-conductive sheet 70 described above.

[0042] <Case 36 (Negative Electrode Case 36a)> The negative electrode case 36a is a hollow rectangular parallelepiped as a whole, and is configured to include a negative electrode upper case 90 and a negative electrode lower case 92 that can be assembled and disassembled relative to each other in the vertical direction. The negative electrode upper case 90 and the negative electrode lower case 92 are formed from, for example, synthetic resin.

[0043] <Negative Electrode Upper Case 90> The negative electrode upper case 90 has a generally box-like shape that opens downward as a whole, and includes an upper bottom wall 94 and an upper peripheral wall 96 that protrudes downward from the outer periphery of the upper bottom wall 94. That is, the upper peripheral wall 96 includes an upper front wall 96a that forms the front wall, an upper rear wall 96b that forms the rear wall, an upper left wall 96c that forms the left wall, and an upper right wall 96d that forms the right wall. The negative electrode upper case 90 is formed with a size such that the left-right dimension is larger than the front-to-rear dimension.

[0044] As described above, the negative electrode case 36a is provided with the first air intake hole 44, the first exhaust hole 46, the second air intake hole 48, and the second exhaust hole 50. As will be described later, the negative electrode case 36a is provided with the second fan motor 40 at its left end, and the first fan motor 38 is provided a predetermined distance to the right of the second fan motor 40. Therefore, the negative electrode case 36a has the first air intake hole 44 and the second air intake hole 48 between the first fan motor 38 and the second fan motor 40 in the left-right direction, on the upstream side (left) of the airflow direction α of the first fan motor 38 and on the upstream side (right) of the airflow direction β of the second fan motor 40. The negative electrode case 36a also has the first exhaust hole 46 at its right end, on the downstream side (right) of the airflow direction α of the first fan motor 38. Furthermore, a second exhaust hole 50 is provided at the left end of the negative pole case 36 a downstream (left) in the air blowing direction β of the second fan motor 40 .

[0045] In the first embodiment, the first air intake hole 44, the first exhaust hole 46, the second air intake hole 48, and the second exhaust hole 50 are all provided in the negative electrode upper case 90. In particular, in the first embodiment, the first air intake hole 44 and the second air intake hole 48 are formed in the same part of the negative electrode upper case 90, and the first air intake hole 44 and the second air intake hole 48 are configured by the same hole portion provided in the negative electrode upper case 90.

[0046] Each of the first air intake hole 44, the first exhaust hole 46, the second air intake hole 48, and the second exhaust hole 50 is formed by a plurality of through holes 98 that penetrate in the thickness direction through each wall portion of the negative electrode upper case 90. The through holes 98 that penetrate each wall portion of the negative electrode upper case 90 are aligned in the front-rear direction and / or the left-right direction.

[0047] The first air intake hole 44 and the second air intake hole 48 are formed by a plurality of through-holes 98 that penetrate the upper bottom wall 94, the upper front wall 96a, and the upper rear wall 96b in the thickness direction in the left-right direction between the first fan motor 38 and the second fan motor 40 (intake area 106 described later). In other words, the first air intake hole 44 and the second air intake hole 48 are formed by sharing a plurality of through-holes 98 in the region of the negative electrode upper case 90 that covers the intake area 106.

[0048] The first exhaust holes 46 are formed by a plurality of through-holes 98 that penetrate the upper bottom wall 94, the upper front wall 96a, and the upper rear wall 96b in the thickness direction at the right ends thereof and the upper right wall 96d. The second exhaust holes 50 are formed by a plurality of through-holes 98 that penetrate the upper bottom wall 94, the upper front wall 96a, and the upper rear wall 96b in the thickness direction at the left ends thereof and the upper left wall 96c. The size of each through-hole 98 is not limited, but it is preferable that the opening width A (see FIG. 5 ) of each through-hole 98 be, for example, 3 mm or more. Similarly, it is preferable that the opening width of each through-hole 98 that is provided in the left portion of the negative electrode upper case 90 and that constitutes the first intake hole 44, the second intake hole 48, and the second exhaust hole 50 be, for example, 3 mm or more.

[0049] <Negative electrode lower case 92> The negative electrode lower case 92 has a generally box-like shape that opens upward and includes a bottom wall 100 and a lower peripheral wall 102 that protrudes upward from the outer periphery of the bottom wall 100. The negative electrode lower case 92 is formed with a size such that the left-right dimension is larger than the front-to-rear dimension. When the negative electrode upper case 90 and the negative electrode lower case 92 are assembled, the open end of the lower peripheral wall 102 and the open end of the upper peripheral wall 96 are butted together in the vertical direction, so that the upper opening of the lower peripheral wall 102 is covered by the negative electrode upper case 90. The negative electrode lower case 92 may hold, for example, a plurality of nuts (not shown) in a generally embedded state.

[0050] The method for fixing the negative electrode upper case 90 and negative electrode lower case 92 having the above-described shapes is not limited, but the upper case 90 and lower case 92 can be fixed, for example, by locking engagement using projections and recesses provided at corresponding positions on the upper peripheral wall portion 96 and the lower peripheral wall portion 102. Furthermore, the upper peripheral wall portion 96 and / or the lower peripheral wall portion 102 of the negative electrode case 36a may be formed with insertion holes that penetrate each wall portion in the thickness direction, through which external electric wires (not shown) connected to the external connection portions 78, 80 and the fan drive unit 42 are inserted.

[0051] <First and Second Fan Motors 38, 40> Known fan motors may be used for the first and second fan motors 38, 40, and blades (not shown) provided inside the motors rotate about central axes L and M, respectively, to generate airflows from one axial direction to the other of the fan motors 38, 40. The first and second fan motors 38, 40 may, for example, have the same shape and be arranged in opposite directions, so that airflows are generated from the fan motors 38, 40 in opposite directions.

[0052] In the first embodiment, the first fan motor 38 is disposed to the right of the second fan motor 40, and the first fan motor 38 generates an airflow (airflow direction α) from left to right, while the second fan motor 40 generates an airflow (airflow direction β) from right to left. In particular, in the first embodiment, as shown in FIG. 4 , the central axes L and M of the fan motors 38 and 40 are located approximately in the center of the negative-pole circuit unit 10a in the front-to-rear direction in a plan view, and the fan motors 38 and 40 are disposed approximately coaxially. Furthermore, by disposing the fan motors 38 and 40, which have the same shape, at a predetermined distance apart, it is possible to avoid problems such as one fan motor mainly blowing air and the other fan motor not blowing enough air.

[0053] In the first embodiment, in the negative pole circuit unit 10a, the first fan motor 38 is provided to the left of the fuse 54, and is located to the left of the relays 52 and fuses 54, which are the heat-generating components 14. In other words, in the negative pole circuit unit 10a, the relays 52 and fuses 54, which are the heat-generating components 14, are located downstream (to the right) of the first fan motor 38 in the airflow direction α, and are not located upstream of the first fan motor 38. In other words, the heat sinks 62 fixed above the relays 52 are also located downstream (to the right) of the first fan motor 38 in the airflow direction α.

[0054] Specifically, in the negative pole circuit unit 10a, the space extending downstream from the first fan motor 38 is an air flow path 104 (shown by a two-dot chain line in FIG. 5 ) in which airflow is generated as the blades of the first fan motor 38 rotate. Meanwhile, in the negative pole circuit unit 10a, an air intake area 106 (shown by a two-dot chain line in FIG. 4 ) is formed between the opposing surfaces of the first fan motor 38 and the second fan motor 40, and the air in the air intake area 106 is blown downstream as the blades of the first and second fan motors 38, 40 rotate.

[0055] The airflow path 104 is, for example, an area surrounded by the negative electrode case 36a (the negative electrode upper case 90 and the negative electrode lower case 92) in the negative electrode circuit unit 10a. In the first embodiment, the airflow path 104 extends in the left-right direction downstream of the first fan motor 38 with a substantially constant cross-sectional area (cross-sectional area in a cross section perpendicular to the left-right direction). This allows air to flow through the airflow path 104 with a substantially constant cross-sectional area. In particular, in the first embodiment, the fuse 54, which generates a relatively small amount of heat, is disposed on the upstream side (left) of the airflow path 104 in the negative electrode circuit unit 10a, and the relays 52, which generate a relatively large amount of heat, are disposed on the downstream side (right) thereof.

[0056] On the other hand, as described above, the second fan motor 40 is provided at the left end portion of the negative pole circuit unit 10a, and rotation of its blades around the central axis M generates an airflow (airflow direction β) from right to left. That is, the second fan motor 40 blows air in the intake area 106 to the left of the negative pole circuit unit 10a through the second exhaust hole 50 provided at the left end of the negative pole circuit unit 10a. Therefore, the second fan motor 40 is disposed upstream of the first fan motor 38 in the airflow direction α of the first fan motor 38, with the intake side of the second fan motor 40 facing the first fan motor 38.

[0057] The first and second fan motors 38, 40 described above, with a plurality of blades (not shown) housed in a case, are fixed to a support frame 108, for example, by bolts. These support frames 108 are then fixed to the negative-pole lower case 92, for example, by bolts, so that the fan motors 38, 40 are fixed to the negative-pole case 36a.

[0058] <The Other Circuit Unit (Positive Polarity Circuit Unit 10b)> Figure 8 shows the positive polarity circuit unit 10b, which is the other circuit unit of the pair of circuit units 10. As described above, the positive polarity circuit unit 10b includes a positive polarity circuit component 34b including the heat-generating component 14, and a positive polarity case 36b that houses the positive polarity circuit component 34b. The basic structure of the positive polarity circuit unit 10b is similar to that of the negative polarity circuit unit 10a, and only a brief description of the positive polarity circuit unit 10b will be given. In the positive polarity circuit unit 10b, components and parts that are substantially the same as those in the negative polarity circuit unit 10a are designated in the figure by the same reference numerals as those in the negative polarity circuit unit 10a.

[0059] The positive-pole circuit configuration unit 34b also includes a relay 52 as a first heat-generating component and a fuse 54 as a second heat-generating component as heat-generating components 14. In the first embodiment, two relays 52, 52 are provided in the left portion of the positive-pole circuit unit 10b, spaced apart from each other in the left-right direction. A heat sink 62 is thermally connected to each terminal 58 of each relay 52. ​​The heat sinks 62 are provided at approximately the same position in the front-to-rear direction and are continuous with each other in the left-to-right direction. Current-carrying bus bars 72d-72g are connected to each terminal 58 of each relay 52 with bolts (not shown), and the relays 52 and heat sinks 62 are fixed via the current-carrying bus bars 72d-72g and the insulating thermally conductive sheets 70. As a result, heat generated by each relay 52 is transferred to each heat sink 62 via the current-carrying bus bars 72d-72g and the insulating thermally conductive sheets 70.

[0060] Further, a precharge relay 109 and a precharge resistor 110 are provided on the rear side of the right portion of the positive electrode circuit unit 10b. The fuse 54, precharge relay 109, and precharge resistor 110 provided on the right portion of the positive electrode circuit unit 10b all generate less heat than the respective relays 52 provided on the left portion of the positive electrode circuit unit 10b.

[0061] <Circuit Configuration Unit 34 (Positive Pole Circuit Configuration Unit 34b)> In the first embodiment, the positive pole circuit configuration unit 34b in the positive pole circuit unit 110b includes the relays 52 as first heat-generating components, the fuse 54 as second heat-generating components, the energizing bus bars 72b to 72g, the pre-charge relay 109, and the pre-charge resistor 110. Heat dissipation bus bars 84 are fixed to the energizing bus bars 72b to 72g with bolts (e.g., bolts 76). The heat dissipation portions 86 of the heat dissipation bus bars 84 are overlapped with a positive pole lower case 114 (described later) that constitutes the case 36 (positive pole case 36b) via insulating thermally conductive sheets 88.

[0062] <Case 36 (positive electrode case 36b)> The positive electrode case 36b is a hollow rectangular parallelepiped as a whole, and is configured to include a positive electrode upper case 112 and a positive electrode lower case 114 that can be assembled and disassembled relative to each other in the vertical direction. The positive electrode upper case 112 and the positive electrode lower case 114 are formed from, for example, synthetic resin.

[0063] <Positive electrode upper case 112> The positive electrode upper case 112 has the same shape as the negative electrode upper case 90, and includes an upper bottom wall portion 94 and an upper peripheral wall portion 96 that protrudes downward from the outer peripheral edge of the upper bottom wall portion 94. The upper peripheral wall portion 96 includes an upper front wall portion 96a, an upper rear wall portion 96b, an upper left wall portion 96c, and an upper right wall portion 96d.

[0064] <Positive electrode lower case 114> The positive electrode lower case 114 has a shape similar to that of the negative electrode lower case 92 and includes a bottom wall 100 and a lower peripheral wall 102 that protrudes upward from the outer peripheral edge of the bottom wall 100. The positive electrode upper case 112 and the positive electrode lower case 114 may be fixed to each other by a locking fit using projections and recesses, or by other known fixing means. Similarly to the negative electrode case 36a, the positive electrode case 36b may have a wire insertion hole through which an external electric wire (not shown) is inserted. This wire insertion hole may be provided in the positive electrode upper case 112, or may be provided across both the positive electrode upper case 112 and the positive electrode lower case 114.

[0065] <Other-side air intake hole 116 and other-side exhaust hole 118> The positive pole case 36b in the positive pole circuit unit 10b is provided downstream (left) in the air blowing direction β of the second fan motor 40, and the air blown by the second fan motor 40 passing through the second exhaust hole 50 passes through the other-side air intake hole 116 provided in the positive pole case 36b. In addition, the other-side exhaust hole 118 is provided in the positive pole case 36b downstream (left) of the other-side air intake hole 116 in the air blowing direction β of the second fan motor 40.

[0066] Specifically, a second-side air intake hole 116 is provided at the right end of the positive electrode case 36b, and a second-side exhaust hole 118 is provided at the left end of the positive electrode case 36b. In the first embodiment, both the second-side air intake hole 116 and the second-side exhaust hole 118 are provided in the positive electrode upper case 112 of the positive electrode case 36b. As will be described later, air that flows into the positive electrode circuit unit 10b through the second-side air intake hole 116 is exhausted to the outside of the positive electrode circuit unit 10b through the second-side exhaust hole 118. Therefore, in the positive electrode circuit unit 10b, substantially the entire internal space of the positive electrode circuit unit 10b is the air flow path 119.

[0067] The heat-generating components 14 (relays 52, fuse 54, precharge relay 109, and precharge resistor 110) in the positive-polarity circuit unit 10b are arranged between the other-side air intake hole 116 and the other-side air exhaust hole 118 in the air blowing direction β of the second fan motor 40. In the first embodiment, also in the positive-polarity circuit unit 10b, the fuse 54, precharge relay 109, and precharge resistor 110, which generate relatively little heat, are arranged upstream (to the right) of the air blowing path 119, and the relays 52, which generate relatively large amounts of heat, are arranged downstream (to the left). In addition, the heat sinks 62 fixed above the relays 52 are also arranged downstream (to the left) of the second fan motor 40 in the air blowing direction β.

[0068] The other-side intake hole 116 and the other-side exhaust hole 118 are formed by a plurality of through holes 120 that penetrate each wall of the positive electrode upper case 112 in the thickness direction. These through holes 120 are aligned in the front-rear and / or left-right directions. In other words, the other-side intake hole 116 is formed by a plurality of through holes 120 that penetrate each wall in the thickness direction at the right ends of the upper bottom wall 94, the upper front wall 96a, and the upper rear wall 96b, and at the upper right wall 96d. The other-side exhaust hole 118 is formed by a plurality of through holes 120 that penetrate each wall in the thickness direction at the left ends of the upper bottom wall 94, the upper front wall 96a, and the upper rear wall 96b, and at the upper left wall 96c.

[0069] As described above, the pair of circuit units 10 (negative and positive electrode 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 restriction units 30 (negative and positive electrode exhaust direction restriction units 30a, 30b) described above are provided in the front portion of the housing body 24, and the circuit units 10a, 10b are disposed between the exhaust direction restriction units 30a, 30b and the front wall of the housing body 24.

[0070] The negative and positive circuit units 10a, 10b are disposed relatively close to each other but slightly spaced apart, with the second exhaust hole 50 in the negative circuit unit 10a and the other-side intake hole 116 in the positive circuit unit 10b facing each other. As described above, the negative circuit unit 10a has a longer length in the left-right direction than the positive circuit unit 10b, and the second exhaust hole 50 provided at the left end of the negative circuit unit 10a is located to the left of the left-right center of the housing main body 24. In the first embodiment, the intake area 106 between the first fan motor 38 and the second fan motor 40 in the negative circuit unit 10a is located in the left-right center of the housing main body 24.

[0071] The first exhaust hole 46 in the negative electrode circuit unit 10a and the other-side exhaust hole 118 in the positive electrode circuit unit 10b are arranged facing the wall portions on both the left and right sides of the housing main body 24. In other words, the first exhaust hole 46 and the other-side exhaust hole 118 are arranged on the peripheral portions on both the left and right sides of the housing main body 24.

[0072] <Assembly of a pair of circuit units 10 (negative and positive polarity circuit units 10a, 10b)> A specific example of a method for assembling each of the negative and positive polarity circuit units 10a, 10b will be described below. Note that the method for assembling the negative and positive polarity circuit units 10a, 10b is not limited to the embodiment described below.

[0073] First, the assembly method for the negative-electrode circuit unit 10a will be described. First, the relays 52 and fuses 54 are bolted to the negative-electrode lower case 92 along with the current-carrying bus bars 72b-72g and the heat-dissipating bus bars 84. Note that insulating and heat-conducting sheets 88 are provided in advance on the upper surface of the bottom wall 100 of the negative-electrode lower case 92 and / or the lower surface of the heat-dissipating portion 86 of each heat-dissipating bus bar 84. The heat sinks 62 are then superimposed on the portions 72a of the current-carrying bus bars 72d-72g that cover the relays 52 via the insulating and heat-conducting sheets 70, and secured with bolts or the like. The first and second fan motors 38, 40 are secured to the negative-electrode lower case 92 via the support frame 108, and the fan drive unit 42 is housed and secured in the negative-electrode lower case 92. Thereafter, the fan drive unit 42 and the first and second fan motors 38, 40 are electrically connected by the respective electric wires 82. Next, the negative pole upper case 90 is brought close from above and fixed to the negative pole lower case 92, thereby completing the negative pole circuit unit 10a.

[0074] Next, the assembly method for the positive-polarity circuit unit 10b will be described. First, the relays 52 and fuses 54 are bolted to the positive-polarity lower case 114 along with the current-carrying bus bars 72b-72g and the heat-dissipating bus bars 84. Note that insulating and heat-conducting sheets 88 are provided in advance on the upper surface of the bottom wall 100 of the positive-polarity lower case 114 and / or the underside of the heat-dissipating portion 86 of each heat-dissipating bus bar 84. The heat sinks 62 are then placed over the portions 72a of the current-carrying bus bars 72d-72g that cover the relays 52, with the insulating and heat-conducting sheets 70 interposed between them, and then secured with bolts or the like. The pre-charge relays 109 and pre-charge resistors 110 are then electrically connected to the appropriate current-carrying bus bars 72. Next, the positive electrode upper case 112 is brought close from above to fix the positive electrode upper case 112 and the positive electrode lower case 114 together, thereby completing the positive electrode circuit unit 10b.

[0075] These negative and positive circuit units 10a, 10b are disposed in the housing body 24 in which the exhaust direction restriction units 30a, 30b are provided, between the respective exhaust direction restriction units 30a, 30b and the front wall of the housing body 24. In this manner, the housing body 24 in which the negative and positive circuit units 10a, 10b are provided contains a plurality of battery cells 18 and a BMS board 22, which are electrically connected, and an upper opening 26 of the housing body 24 is covered with a lid 28, thereby forming the battery pack 12.

[0076] In this battery pack 12, for example, when the fan drive unit 42 detects that the temperature inside the negative electrode circuit unit 10a exceeds a predetermined temperature, a fan drive signal is sent to the first and second fan motors 38, 40, thereby driving the first and second fan motors 38, 40. Alternatively, when the BMS board 22 detects that the temperature inside the battery pack 12 exceeds a predetermined temperature, a signal for driving the first and second fan motors 38, 40 is sent to the first and second fan motors 38, 40 via the fan drive unit 42, thereby driving the first and second fan motors 38, 40.

[0077] Here, in the negative electrode circuit unit 10a, when the first fan motor 38 is driven, air is drawn from the outside of the negative electrode circuit unit 10a into the intake area 106 through the first air intake hole 44, and the air in the intake area 106 is blown in the air blowing direction α by the first fan motor 38. When the air blown by the first fan motor 38 reaches the right end of the negative electrode circuit unit 10a, it is exhausted to the outside of the negative electrode circuit unit 10a through the first exhaust hole 46. The air exhausted from the first exhaust hole 46 is redirected by the inclined surface 32 of the negative electrode exhaust direction restricting portion 30a and flows in a direction (forward) away from the battery cells 18. The air redirected by the inclined surface 32 then flows inward (leftward) in the left-right direction between the negative electrode circuit unit 10a and the front wall of the housing main body 24 and returns to the left-right center of the housing main body 24. The air that has returned to the center in the left-right direction of the housing body 24 is again drawn into the intake area 106 through the first intake holes 44 and circulates.

[0078] Furthermore, in the negative pole circuit unit 10a, when the second fan motor 40 is driven, air is drawn into the intake area 106 from outside the negative pole circuit unit 10a through the second air intake hole 48, and the air in the intake area 106 is blown in the air blowing direction β by the second fan motor 40. The air blown by the second fan motor 40 is exhausted through the second exhaust hole 50, and flows into the positive pole circuit unit 10b through the other-side air intake hole 116 in the positive pole circuit unit 10b located opposite the second exhaust hole 50.

[0079] The air that flows into the positive circuit unit 10b through the other-side intake hole 116 is blown in the airflow direction β. When it reaches the left end of the positive circuit unit 10b, it is discharged to the outside of the positive circuit unit 10b through the other-side exhaust hole 118. The air discharged from the other-side exhaust hole 118 is redirected by the inclined surface 32 of the positive exhaust direction restricting portion 30b and moves in a direction (forward) away from the battery cells 18. The air that has been redirected by the inclined surface 32 then flows inward (to the right) between the positive circuit unit 10b and the front wall of the housing body 24 and returns to the center of the housing body 24. The air that has returned to the center of the housing body 24 is again drawn into the intake area 106 through the second intake hole 48 and circulates.

[0080] Each circuit component 34a, 34b in each circuit unit 10a, 10b has heat-generating components 14, such as relays 52 and fuses 54, and these components, which generate heat when energized, are cooled by air blown by the first and second fan motors 38, 40. In particular, in the first embodiment, exhaust direction restriction units 30a, 30b are provided to restrict the direction of exhaust from each circuit unit 10a, 10b, and the air heated as it passes through each circuit unit 10a, 10b is redirected by the inclined surfaces 32 to flow away from the battery cells 18. This more reliably prevents air heated by the heat-generating components 14 (such as the relays 52 and fuses 54) from flowing toward the battery modules 16 (such as the battery cells 18) and adversely affecting the battery modules 16. The air discharged from the first exhaust hole 46 and the other-side exhaust hole 118 can be cooled by coming into contact with the wall of the housing body 24 of the battery pack 12, and the air discharged from the first exhaust hole 46 and the other-side exhaust hole 118 can be drawn in at a lower temperature from the first and second intake holes 44, 48. As a result, the heat generated in the heat-generating component 14 can be cooled more efficiently.

[0081] In such a pair of circuit units 10 (each circuit unit 10a, 10b), one circuit unit (negative-pole circuit unit 10a) houses and disposes a first fan motor 38 and a second fan motor 40 that generate airflows (airflow directions α, β) that flow through each circuit unit 10a, 10b, and a fan drive unit 42 that drives these. This allows for a reduction in the number of electric wires (wire harnesses), etc., and also reduces the number of assembly steps, compared to, for example, a case in which a fan motor and a fan drive unit are provided within each circuit unit. Furthermore, because electric wires (wire harnesses), etc., do not extend across each circuit unit 10a, 10b, the structure of each circuit unit 10a, 10b can be simplified.

[0082] In each of the circuit units 10a, 10b, a heat sink 62 is thermally connected to each relay 52, which is a heat-generating component 14, and each heat sink 62 is disposed downstream of the first fan motor 38 and the second fan motor 40 in the airflow directions α, β. This allows heat generated in each relay 52 to be transferred to the corresponding heat sink 62, and this heat is effectively dissipated by the airflow from the first and second fan motors 38, 40. In particular, in the first embodiment, in the airflow paths 104, 119 for the airflow from the first and second fan motors 38, 40, fuses 54 and the like, which generate relatively little heat, are disposed upstream of the airflow directions α, β, while relays 52, which generate relatively large amounts of heat, are disposed downstream of the airflow directions α, β. This prevents air from being heated by the relays upstream of the airflow paths 104, 119, preventing relatively high-temperature air from flowing downstream of the airflow paths 104, 119. In other words, relatively low temperature air heated by the fuse 54 or the like can be blown toward each relay 52 located downstream of each air flow path 104, 119, allowing the heat generated in each relay 52 to be dissipated more stably.

[0083] In the negative electrode circuit unit 10a, an intake area 106 is defined between the opposing surfaces of the first fan motor 38 and the second fan motor 40, and a plurality of through holes 98 are provided in the region of the negative electrode case 36a that covers the intake area 106, and these plurality of through holes 98 are shared to define the first intake hole 44 and the second intake hole 48. This avoids an increase in size of the negative electrode circuit unit 10a and simplifies the structure of the negative electrode circuit unit 10a compared to when the first intake hole 44 and the second intake hole 48 are provided separately.

[0084] In the negative-pole circuit unit 10a, the heat-generating components 14 (relays 52 and fuses 54) are arranged downstream (to the right) of the first fan motor 38 in the airflow direction α, and are not arranged upstream (to the left) of the first fan motor 38 in the airflow direction α. ​​This prevents air whose temperature has increased due to heat generation by the heat-generating components 14 from affecting the first fan motor 38. Furthermore, air whose temperature has increased by passing through the heat-generating components 14 is cooled by coming into contact with the housing main body 24 while being discharged from the first exhaust hole 46 and circulating to the first intake hole 44, so that it is possible to reliably prevent high-temperature air from affecting the first fan motor 38 and adversely affecting its operation.

[0085] <Modifications> Although the first embodiment has been described above in detail as a specific example of the present disclosure, the present disclosure is not limited to this specific description. Modifications, improvements, etc. within the scope of achieving the object of the present disclosure are included in the present disclosure. For example, the following modifications of the embodiment are also included in the technical scope of the present disclosure.

[0086] (1) In the above embodiment, the exhaust direction restricting portions 30a, 30b were provided separately from the circuit units 10a, 10b on both left and right wall portions of the housing body 24 of the battery pack 12. However, this is not limited to this. For example, as in the pair of circuit units 130 (negative electrode circuit unit 130a and positive electrode circuit unit 130b) shown in FIG. 9 , the exhaust direction restricting portions 132 may be formed integrally with the cases 36 (negative electrode case 36a and positive electrode case 36b) of the circuit units 130a, 130b, or may be formed separately and then attached. Note that the exhaust direction restricting portions are not essential to each circuit unit according to the present disclosure. Furthermore, even when the exhaust direction restricting portions are provided in the battery pack as in the above embodiment, they are not limited to being provided on both left and right wall portions of the housing body. They may also be provided on the bottom wall of the housing body or on the lid.

[0087] (2) In the above embodiment, the first and second fan motors 38, 40 and the fan drive unit 42 were provided in the negative-polarity circuit unit 10a. However, the first and second fan motors and the fan drive unit may be provided in the positive-polarity circuit unit. When the first and second fan motors and the fan drive unit are provided in the negative-polarity circuit unit, the specific configuration of the positive-polarity circuit unit is not limited as long as it includes a circuit configuration unit including heat-generating components and a case that houses the circuit configuration unit and has an air intake port and an air exhaust port on the other side. For example, the heat-generating components may be only one of a relay and a fuse, and a heat-dissipating bus bar or heat sink is not required.

[0088] (3) In the above embodiment, the fan drive unit 42 also has a monitoring function for monitoring the internal state of the negative electrode circuit unit 10a, but this is not limited to this. That is, as exemplified in the above embodiment, the internal state of the battery pack may be monitored by the BMS board, and when the BMS board detects that the temperature or current value exceeds a predetermined value, the BMS board may send a signal to the fan drive unit to drive the fan, and the fan drive unit may drive the first and second fan motors.

[0089] (4) The first fan motor and the second fan motor do not need to operate simultaneously. For example, the first fan motor and the second fan motor may be operated alternately to blow air alternately to the negative pole circuit unit and the positive pole circuit unit, or the first fan motor and the second fan motor may be operated with a time lag.

[0090] (5) In the above embodiment, the first intake hole 44 and the second intake hole 48 are configured by sharing a plurality of through holes 98. However, the first intake hole and the second intake hole may be provided separately, for example, by providing a partition wall between the first fan motor and the second fan motor. Note that at least one of the first intake hole, the first exhaust hole, the second intake hole, the second exhaust hole, the other-side intake hole, and the other-side exhaust hole is not limited to being formed by a plurality of through holes, but may be formed by a single hole that penetrates the case in the thickness direction. Furthermore, these intake holes and exhaust holes are not limited to being formed in the upper case that constitutes the case, but may be formed in the lower case, or in both the upper and lower cases.

[0091] (6) In the above embodiment, in the negative-pole circuit unit 10a, the heat-generating components 14 (relays 52 and fuse 54) are disposed downstream (to the right) of the first fan motor 38 in the airflow direction α. ​​However, this is not limited to this. For example, in the negative-pole circuit unit, the heat-generating components may be disposed upstream of the first fan motor in the airflow direction, i.e., the heat-generating components may be disposed between the first fan motor and the second fan motor. In this case, the heat-generating components disposed between the first fan motor and the second fan motor are preferably heat-generating components with a small amount of heat, such as fuses.

[0092] REFERENCE SIGNS LIST 10 Pair of circuit units (first embodiment) 10a Negative electrode circuit unit (one circuit unit) 10b Positive electrode circuit unit (the other circuit unit) 12 Battery pack 14 Heat-generating component 16 Battery module 18 Battery cell 20 Housing 22 BMS board 24 Housing body 26 Upper opening 28 Lid 30 Exhaust direction restricting portion 30a Negative electrode exhaust direction restricting portion 30b Positive electrode exhaust direction restricting portion 32 Inclined surface 34 Circuit configuration portion 34a Negative electrode circuit configuration portion 34b Positive electrode circuit configuration portion 36 Case 36a Negative electrode case 36b Positive electrode case 38 First fan motor 40 Second fan motor 42 Fan drive portion 44 First air intake hole 46 First air exhaust hole 48 Second air intake hole 50 Second air exhaust hole 52 Relay (first heat-generating component) 54 Fuse (second heat-generating component) 56 Case body 58 Terminal portion 60 Insulating partition plate 62 Heat sink 64 Plate-shaped portion 66 Heat sink 68 Gap 70 Insulating heat-conducting sheet 72 Current-carrying bus bar 72a Portion of current-carrying bus bar covering the upper part of the relay 72b to 72g Current-carrying bus bar 74 Terminal portion 76 Bolt 78, 80 External connection portion 82 Electric wire 84 Heat-dissipating bus bar 86 Heat-dissipating portion 88 Insulating heat-conducting sheet 90 Negative electrode upper case 92 Negative electrode lower case 94 Upper bottom wall portion 96 Upper peripheral wall portion 96a Upper front wall portion 96b Upper rear wall portion 96c Upper left wall portion 96d Upper right wall portion 98 Through hole 100 Bottom wall portion 102 Lower peripheral wall portion 104 Air flow path 106 Air intake area 108 Support frame 109 Precharge relay 110 Precharge resistor 112 Positive electrode upper case 114 Positive electrode lower case 116 Other side air intake hole 118 Other side exhaust hole 119 Air flow path 120 Through hole 130 Pair of circuit units (another embodiment) 130a Negative electrode circuit unit 130b Positive electrode circuit unit 132 Exhaust direction restricting portion α, β Air flow direction L, M Central axis

Claims

1. A pair of circuit units housed within a battery pack housing, each of the circuit units comprising: a circuit configuration section including a heat-generating component; and a case housing the circuit configuration section, one of the pair of circuit units comprising: a first fan motor and a second fan motor; and a fan drive section provided in the circuit configuration section and driving the first fan motor and the second fan motor, the case of the one of the circuit units having a first intake hole provided upstream in the air blowing direction of the first fan motor, a first exhaust hole provided downstream in the air blowing direction of the first fan motor, a second intake hole provided upstream in the air blowing direction of the second fan motor, and a second exhaust hole provided downstream in the air blowing direction of the second fan motor, the heat-generating component of the one of the circuit units being located downstream of the first fan motor and upstream of the first exhaust hole in the air blowing direction of the first fan motor, A pair of circuit units, wherein the case of the other circuit unit is provided downstream in the air blowing direction of the second fan motor and has a other-side intake hole through which the air blown by the second fan motor passing through the second exhaust hole passes, and a other-side exhaust hole located downstream of the other-side intake hole in the air blowing direction of the second fan motor, and the heat-generating component of the other circuit unit is located between the other-side intake hole and the other-side exhaust hole in the air blowing direction of the second fan motor.

2. A pair of circuit units as described in claim 1, comprising a heat sink thermally connected to each of the heat-generating components, each of the heat sinks being positioned downstream in the air blowing direction of the first fan motor or the second fan motor.

3. A pair of circuit units as described in claim 1 or claim 2, wherein the second fan motor is positioned upstream of the first fan motor in the air blowing direction of the first fan motor, with the intake side of the second fan motor facing the first fan motor, an intake area is defined between the opposing surfaces of the first fan motor and the second fan motor, and a plurality of through holes are provided in an area covering the intake area in the case of one of the circuit units, and the first intake hole and the second intake hole are defined by sharing the plurality of through holes.

4. A pair of circuit units as described in claim 1 or claim 2, wherein the heat-generating components of one of the circuit units are positioned downstream of the first fan motor in the air blowing direction, and are not positioned upstream of the first fan motor.

Images