Circuit unit

Abstract

The present invention discloses a circuit unit that is accommodated in a battery pack housing and makes it possible to reduce the number of parts and assembly man-hours.　The present invention is a circuit unit 10 accommodated in a housing 20 of a battery pack 12, the circuit unit being provided with: a circuit configuration section 38 configured to include a temperature sensor 36 and / or a current sensor 37; and a drive component 40 driven by power from the circuit configuration section 38, wherein the circuit configuration section 38 has a drive unit 42 that turns the drive power of the drive component 40 on and off, and the drive unit 42 turns the drive power of the drive component 40 on and off in accordance with a detection value of the temperature sensor 36 and / or the current sensor 37.

Description

Circuit Unit

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

[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] Incidentally, 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 fan motor and a heat-generating component such as a relay, as exemplified in Patent Document 1. In such cases, the fan motor installed in the 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 BMS (Battery Management System) or the like installed in the same battery pack to the circuit unit, which results in an increase in the number of parts and assembly steps.

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

[0006] The circuit unit of the present disclosure is a circuit unit housed within the housing of a battery pack, and comprises a circuit configuration section including at least one of a temperature sensor and a current sensor, and a drive component driven by power from the circuit configuration section, wherein the circuit configuration section has a drive section that switches the drive power of the drive component on and off, and the drive section switches the drive power of the drive component on and off depending on the detection value of at least one of the temperature sensor and the current sensor.

[0007] According to the present disclosure, it is possible to provide a circuit unit that is housed in a battery pack housing, which allows for a reduction in the number of parts and assembly steps.

[0008] FIG. 1 is a perspective view showing a battery pack including a circuit unit according to a first embodiment with a lid that constitutes a housing removed. FIG. 2 is a plan view showing an enlarged view of a main part of the battery pack shown in FIG. 1. FIG. 3 is a perspective view showing a circuit unit according to a 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 a vertical cross-sectional view showing an enlarged view of the 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 component that constitutes the circuit unit shown in FIG. 3 in an exploded state. FIG. 8 is a plan view showing an enlarged view of a main part of a battery pack including a circuit unit according to another aspect of the present disclosure, and corresponds to FIG. 2.

[0009] <Description of Embodiments of the Present Disclosure> First, embodiments of the present disclosure will be listed and described. The circuit unit of the present disclosure is: (1) a circuit unit accommodated in a housing of a battery pack, the circuit unit including a circuit configuration unit including at least one of a temperature sensor and a current sensor, and a driving component driven by power from the circuit configuration unit, the circuit configuration unit having a driving unit that switches ON / OFF the driving power of the driving component, and the driving unit switches ON / OFF the driving power of the driving component in accordance with a detection value of at least one of the temperature sensor and the current sensor.

[0010] According to this aspect, in a circuit unit housed in a battery pack housing, a circuit configuration section is equipped with at least one of a temperature sensor and a current sensor, and the drive section mounted on the circuit configuration section can turn on / off the drive power of the drive components driven by power from the circuit configuration section. Furthermore, the drive section is configured to switch on / off the drive power of the drive components depending on the detected values ​​of the temperature sensor and / or current sensor mounted on the same circuit configuration section. Therefore, the drive control of the drive components can be performed entirely by the circuit configuration section mounted on the circuit unit, eliminating the need for a process of routing and assembling a wire harness, including electric wires for the drive power supply and control signals for the drive components, to the circuit unit, as required in conventional structures. As a result, a circuit unit housed in a battery pack housing can be provided that reduces the number of components and assembly steps.

[0011] The driving component may be any driving component whose driving control is performed based on the detection values ​​of a temperature sensor or current sensor mounted on the circuit configuration section of the circuit unit, such as a fan motor that cools heat-generating components mounted on the circuit unit.

[0012] (2) In the above (1), it is preferable that the circuit assembly includes a heat-generating component, and the driving component is a fan motor that promotes cooling of the heat-generating component. Circuit units housed in battery packs often include heat-generating components such as relays and fuses, and a fan motor, which is a driving component, may be installed to cool the heat-generating component. In such cases, the fan motor can be switched on and off based on the detected values ​​of a temperature sensor or current sensor installed in the circuit assembly. As a result, in addition to reducing the number of components and assembly steps, it is possible to achieve more appropriate fan motor driving based on the temperature and current values ​​within the circuit unit, which may also contribute to improving the operational stability of the circuit unit.

[0013] (3) In the above (2), it is preferable that the heat-generating component includes a first heat-generating component thermally connected to a heat sink, and that the first heat-generating component and the heat sink are located downstream of the fan motor in the airflow direction of the fan motor. Heat from the heat-generating component is efficiently transferred to the heat sink from the terminals, which are the most heat-transferable, 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 in the circuit unit.

[0014] (4) In the above (3), it is preferable that the heat-generating component includes a second heat-generating component disposed upstream of the fan motor in the airflow direction, and that the heat generation amount of the second heat-generating component is smaller than the heat generation amount of the first heat-generating component. Due to requirements such as space and circuit configuration within the battery pack, it may not be possible to place the fan motor at an end of the circuit unit. Even in such a case, by disposing 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, the conditions on the intake side of the fan motor can be satisfactorily met, while the first heat-generating component, which generates a larger heat generation amount, can be efficiently dissipated by utilizing the airflow from the fan motor.

[0015] (5) In any one of (2) to (4) above, it is preferable that the fan motor includes a suction path extending from upstream of the fan motor toward the fan motor and a blowing path extending downstream from the fan motor in the airflow direction of the fan motor, and that the cross-sectional area in a direction perpendicular to the airflow direction from the suction path to the blowing path is constant. The cross-sectional area in a direction perpendicular to the airflow direction is constant throughout the entire region from the suction path upstream of the fan motor to the blowing path downstream of the fan motor. This allows air to flow with a constant cross-sectional area from the suction path to the blowing path, thereby preventing areas where air flow is difficult and preventing localized temperature increases, for example, in a circuit unit. In particular, in combination with (3) or (4) above, when a first heat-generating component and a heat sink are disposed in the blowing path or a second heat-generating component is disposed in the suction path, stable air flow in these paths can be achieved, thereby stably dissipating heat from the first heat-generating component and the second heat-generating component.

[0016] (6) In any one of (1) to (5) above, it is preferable that the drive unit turns on the drive power of the drive component when the temperature sensor detects a temperature exceeding a predetermined temperature, and turns off the drive power of the drive component when the temperature sensor detects a temperature lower than the predetermined temperature or when a predetermined time has elapsed since the drive component was activated. A specific example of the drive unit's ON / OFF switching of the drive power of the drive component is, for example, turning on the drive power of the drive component when the temperature sensor detects a temperature exceeding a predetermined temperature, and turning off the drive power of the drive component when the temperature sensor detects a temperature lower than the predetermined temperature or when a predetermined time has elapsed since the drive component was activated. That is, the drive unit may only switch the drive power of the drive component ON / OFF in response to the temperature sensor's detected value from OFF to ON, and the switching of the drive power of the drive component from ON to OFF does not necessarily have to be in response to the temperature sensor's detected value.

[0017] (7) In any one of (1) to (6) above, it is preferable that the drive unit turns on the drive power of the drive component when the detection value of the current sensor exceeds a predetermined value, and turns off the drive power of the drive component when the detection value of the current sensor falls below the predetermined value or when a predetermined time has elapsed since the drive component was driven. A specific example of how the drive unit switches on / off the drive power of the drive component is, for example, to turn on the drive power of the drive component when the detection value of the current sensor exceeds a predetermined value, and to turn off the drive power of the drive component when the detection value of the current sensor falls below the predetermined value or when a predetermined time has elapsed since the drive component was driven. In other words, the drive component may only switch on / off the drive power of the drive component in response to the detection value of the current sensor from OFF to ON, and the switching of the drive power of the drive component from ON to OFF does not have to be in response to the detection value of the current sensor.

[0018] <Details of Embodiments of the Present Disclosure> Specific examples 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.

[0019] First Embodiment A circuit unit 10 according to a first embodiment of the present disclosure will be described below with reference to FIGS. 1 to 7 . The circuit unit 10 is housed within a battery pack 12 in an electric vehicle or a hybrid vehicle and can prevent, for example, the battery module 16 in the battery pack 12 from being adversely affected by heat generated by a heat-generating component 14 disposed within the circuit unit 10. The battery pack 12 can be positioned in any orientation within the vehicle. However, 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 . In addition, when multiple identical components are used, only some of the components will be designated by reference numerals, and the reference numerals may be omitted for other components.

[0020] <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.

[0021] 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.

[0022] 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 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 circuit unit 10 is mounted between the battery module 16 and the front wall of the housing main body 24.

[0023] In the first embodiment, the battery pack 12 is provided with an electric junction box 30 on the left side of the circuit unit 10, and exhaust direction restricting portions 32, 32 that restrict the direction of exhaust air that has passed through the circuit unit 10 and the electric junction box 30 are provided outward in the left-right direction from the circuit unit 10 and the electric junction box 30. In particular, in the first embodiment, each of these exhaust direction restricting portions 32 is formed integrally with the housing main body 24, and each exhaust direction restricting portion 32 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 of the exhaust direction restricting portions 32 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 34 that is inclined with respect to the left-right and front-rear directions.

[0024] <Circuit Unit 10> The circuit unit 10 includes a circuit configuration section 38 configured to include at least one of a temperature sensor 36 and a current sensor 37 (both the temperature sensor 36 and the current sensor 37 in the first embodiment), and a drive component that is driven by power from the circuit configuration section 38. In the first embodiment, the circuit configuration section 38 includes the heat-generating component 14, and the drive component is a fan motor 40 that promotes cooling of the heat-generating component 14. The circuit configuration section 38 also includes a microcomputer 42 as a drive section that switches ON / OFF the drive power of the fan motor 40, which is the drive component.

[0025] In the first embodiment, the circuit unit 10 is electrically connected to the negative electrode of the battery module 16 (the bus bar module connecting each battery cell 18) via an electric wire or the like (not shown), and the electrical junction box 30 is electrically connected to the positive electrode of the battery module 16 (the bus bar module connecting each battery cell 18) via an electric wire or the like (not shown). The circuit unit 10 is provided on the right side of the battery pack 12, and the electrical junction box 30 is provided on the left side of the battery pack 12. The circuit unit 10 and the electrical junction box 30 are each cuboid-shaped and are arranged inside the housing main body 24 so as to extend in the left-right direction.

[0026] <Heat-Generating Component 14 (Relay 44 and Fuse 46)> In the circuit unit 10, the heat-generating component 14 includes a relay 44 as a first heat-generating component and a fuse 46 as a second heat-generating component. In the first embodiment, two relays 44, 44 are provided in the right portion of the circuit unit 10, spaced apart from each other in the left-right direction. Each relay 44 has a case body 48 shaped like a substantially hollow rectangular box. A pair of terminals 50, 50 is exposed from the case body 48 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), spaced apart from each other in the left-right direction. In each case body 48, an insulating partition plate 52 is provided between the terminals 50, 50 to separate the terminals 50.

[0027] A heat sink 54 is thermally connected to each terminal portion 50 of each relay 44. In the first embodiment, two heat sinks 54, 54 are provided with a gap between them in the left-right direction. As shown in FIG. 4 , each heat sink 54 is generally rectangular in plan view, and each heat sink 54 has a plate-like portion 56 extending horizontally (perpendicular to the up-down direction) at its lower end. Each heat sink 54 has a plurality of heat sinks 58 protruding upward from the plate-like portion 56. The heat sinks 58 are arranged in parallel and spaced apart from each other in the front-to-rear direction, extending in the left-to-right direction. This provides a gap 60 extending in the left-to-right direction between the heat sinks 58 in the front-to-rear direction.

[0028] 6 and 7, the terminal portions 50 of the relays 44 are connected with bolts (not shown) to the below-described current-carrying bus bars 64d to 64g that constitute the circuit configuration portion 38. The current-carrying bus bars 64d to 64g extend upward from the locations where they are fixed to the terminal portions 50, and then bend inward in the front-to-rear direction to cover the tops of the relays 44. The heat sinks 54 are fixed to the current-carrying bus bars 64d to 64g via insulating thermally conductive sheets 62 at portions 64a that cover the tops of the relays 44.

[0029] Each insulating thermally conductive sheet 62 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 62 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 64a of the current-carrying bus bars 64d to 64g that cover the relays 44 and the heat sink 54 may be fixed via the insulating thermally conductive sheets 62 with adhesive, bolts, or both adhesive and bolts. This fixes the relays 44 and the heat sinks 54 via the current-carrying bus bars 64d to 64g and the insulating thermally conductive sheets 62, and thermally connects the heat sinks 54 to the terminal portions 50.

[0030] A fuse 46 serving as a second heat-generating component is provided on the rear side of the left portion of the circuit unit 10. The fuse 46 in the circuit unit 10 may be, for example, a pyro fuse. The amount of heat generated by this fuse 46 when energized is smaller than that of each of the relays 44, i.e., the amount of heat generated by the second heat-generating component (fuse 46) is smaller than that of the first heat-generating components (relays 44).

[0031] <Circuit Configuration Unit 38> The relays 44 and fuses 46 are electrically connected by a plurality of energizing bus bars 64. That is, the energizing bus bars 64 are overlapped with a pair of terminals 66, 66 of the fuse 46 and with each terminal 50 of each relay 44, and are fixed by bolts 68 (one is shown in FIG. 5 ). Specifically, an energizing bus bar 64b is fixed to the left terminal 66 of the fuse 46, and the right terminal 66 of the fuse 46 is connected to the left terminal 50 of the left relay 44 by energizing bus bars 64c, 64d. The right terminal 50 of the left relay 44 is connected to the left terminal 50 of the right relay 44 by an energizing bus bar 64e, and an energizing bus bar 64f is fixed to the right terminal 50 of the right relay 44. Further, a separate energizing bus bar 64g, which is separate from the energizing bus bar 64e, is superimposed on and fixed to the right terminal portion 50 of the left relay 44, and extends out to the right.

[0032] As a result, an external connection portion 70 is formed by the end of the current-carrying bus bar 64b at the left end of the circuit unit 10, and external connection portions 72 are formed by the ends of the current-carrying bus bars 64f, 64g at the right end of the circuit unit 10. Terminal portions provided on the ends of external electric wires (not shown) are overlapped with these external connection portions 70, 72 and fixed with bolts or the like, thereby electrically connecting each of the current-carrying bus bars 64b to 64g and each of the relays 44 and fuses 46 to the external electric wires. Although not limited thereto, for example, the external connection portion 70 is connected to the battery module 16 (particularly the bus bar module) to serve as a connection portion for supplying power to the circuit unit 10, and each of the external connection portions 72 is connected to external electrical devices to serve as a connection portion for outputting power to the external electrical devices.

[0033] A monitoring and control unit 74 is provided in the left-right middle portion of the circuit unit 10, specifically between the fuse 46 and the left relay 44. The monitoring and control unit 74 includes the temperature sensor 36, the current sensor 37, and the microcomputer 42 as a drive unit. Specifically, the monitoring and control unit 74 is configured by housing a circuit board 76 on which the temperature sensor 36, the current sensor 37, the microcomputer 42, and the like are mounted in a circuit board case 78. The circuit board 76 is electrically connected to the fan motor 40, which is a drive component, via wires (not shown). In the first embodiment, the electrical junction box 30 also includes a fan motor (not shown) therein, and the circuit board 76 may also be electrically connected to the fan motor of the electrical junction box 30 via wires (not shown).

[0034] That is, in the first embodiment, the temperature sensor 36 in the monitoring and control unit 74 monitors the temperature inside the circuit unit 10, and when the temperature sensor 36 detects that the temperature inside the circuit unit 10 exceeds a predetermined temperature, the microcomputer 42 sends a drive signal to the fan motor 40 of the circuit unit 10. This turns on the drive power for the fan motor 40, causing the fan motor 40 to be driven. In this case, the microcomputer 42 may also send a drive signal to not only the fan motor 40 of the circuit unit 10 but also the fan motor of the electrical junction box 30, causing the fan motor of the electrical junction box 30 to be driven. On the other hand, when the temperature sensor 36 detects that the temperature inside the circuit unit 10 has dropped below a predetermined temperature due to the drive of the fan motor 40, the microcomputer 42 may send a stop signal to the fan motor 40 of the circuit unit 10 and the fan motor of the electrical junction box 30. This turns off the drive power for these fan motors, causing them to be stopped.

[0035] Furthermore, the current sensor 37 in the monitoring and control unit 74 monitors the magnitude of the current flowing through the circuit unit 10. If the current is greater than a predetermined value, the microcomputer 42 sends a drive signal to the fan motor 40 in the circuit unit 10. This turns on the drive power for the fan motor 40, causing the fan motor 40 to operate. Therefore, the board 76 in the monitoring and control unit 74 is electrically connected to one of the current-carrying bus bars 64 (current-carrying bus bars 64b to 64g) in the circuit unit 10. The drive signal from the microcomputer 42 may be sent not only to the fan motor 40 in the circuit unit 10 but also to the fan motor in the electrical junction box 30. Furthermore, if the current sensor 37 detects that the magnitude of the current flowing through the circuit unit 10 has become smaller than a predetermined value after the fan motor 40 has been driven, the microcomputer 42 sends a stop signal to the fan motor 40 in the circuit unit 10 and the fan motor in the electrical junction box 30. This turns off the drive power for these fan motors, causing them to stop.

[0036] That is, the microcomputer 42 can turn on the drive power for the fan motor 40 in response to the detection value of at least one of the temperature sensor 36 and the current sensor 37, thereby driving the fan motor 40. The microcomputer 42 may also be configured to turn off the drive power for the fan motor 40 in response to the detection value of at least one of the temperature sensor 36 and the current sensor 37, thereby stopping the fan motor 40, or may be configured to stop the fan motor 40 after a predetermined time has elapsed since the fan motor 40 started to operate.

[0037] Alternatively, when the BMS board 22 detects that the temperature or current (or voltage) inside the battery pack 12 has exceeded a predetermined value, the BMS board 22 may send a signal to a microcomputer or the like (not shown) that drives the fan motor of the electrical connection box 30, thereby driving the fan motor of the electrical connection box 30.

[0038] Therefore, in embodiment 1, the circuit configuration section 38 in the circuit unit 10 is configured to include each relay 44, which is the first heat-generating component, the fuse 46, which is the second heat-generating component, each current-carrying bus bar 64b to 64g, and the monitoring and control section 74.

[0039] In particular, in the first embodiment, a plurality of heat dissipation bus bars 80 are fixed at the fixed locations between the terminals 66 of the fuse 46 and the current-carrying bus bars 64b, 64c, and at the fixed locations between the terminals 50 of the relays 44 and the current-carrying bus bars 64d to 64g. Each heat dissipation bus bar 80 is generally L-shaped and has a heat dissipation portion 82 extending horizontally and a portion protruding upward from the heat dissipation portion 82. The upward-protruding portion of each heat dissipation bus bar 80 is fastened together with the current-carrying bus bars 64b to 64g to the terminals 66 of the fuse 46 and the terminals 50 of the relays 44 by bolts (e.g., bolts 68). When assembling the circuit unit 10, the heat dissipation portion 82 of each heat dissipation bus bar 80 is placed on a lower case 96 constituting a unit case 92 (described later) via an insulating thermally conductive sheet 84. The insulating heat conductive sheet 84 may be the same as the insulating heat conductive sheet 62 described above.

[0040] <Driving Component (Fan Motor 40)> A known fan motor may be used as the fan motor 40. An internal blade (not shown) rotates around a central axis L to generate an airflow from one axial direction of the fan motor 40 to the other. In the first embodiment, an airflow is generated from left to right in the circuit unit 10. The airflow (airflow direction α) generated by the fan motor 40 in the circuit unit 10 is indicated by a two-dot chain line in FIG. 2. As shown in FIG. 4, the central axis L of the fan motor 40 is located at the center of each heat sink 54 in the front-to-rear direction in a plan view. The fan motor for the electrical junction box 30 may be the same as the fan motor 40 for the circuit unit 10. An airflow (airflow direction β) is generated from right to left in the electrical junction box 30.

[0041] In the first embodiment, the fan motor 40 is disposed between the first heat-generating component (relays 44) and the second heat-generating component (fuse 46) in the circuit unit 10. That is, the relays 44 are disposed on the right side of the fan motor 40, and the fuse 46 is disposed on the left side of the fan motor 40. In short, in the first embodiment, the relays 44 and the heat sinks 54 fixed above the relays 44 are disposed downstream of the fan motor 40 in the air blowing direction α. ​​Furthermore, the fuse 46 is disposed upstream of the fan motor 40 in the air blowing direction α.

[0042] Specifically, in circuit unit 10, the space extending downstream from fan motor 40 is air flow path 86, where airflow is generated as the blades of fan motor 40 rotate. Meanwhile, in circuit unit 10, the space upstream of fan motor 40 is suction path 88 (shown by the two-dot chain line in FIG. 5 ), where airflow is generated in a direction in which air is sucked toward fan motor 40 as air is blown by fan motor 40.

[0043] The above-described air supply path 86 and suction path 88 are areas surrounded by, for example, a unit case 92 (an upper case 94 and a lower case 96) described below. In the first embodiment, the air supply path 86 is approximately the entire area surrounded by the unit case 92 downstream of the fan motor 40. Similarly, the suction path 88 is approximately the entire area surrounded by the unit case 92 upstream of the fan motor 40. As a result, in the circuit unit 10, the air supply path 86 and the suction path 88 are formed with approximately the same cross-sectional area (cross-sectional area in a cross section perpendicular to the left-right direction (air supply direction α)), and air flows through a substantially constant cross-sectional area.

[0044] The fan motor 40, with a plurality of blades (not shown) housed in a case, is fixed to a support frame 90 by, for example, bolts. The support frame 90 is then fixed to an upper case 94 of a unit case 92 (described later) by, for example, bolts, so that the fan motor 40 is fixed to the circuit configuration section 38 via the unit case 92.

[0045] <Unit Case 92> In the circuit unit 10, the circuit configuration section 38, which includes the heat-generating components 14 (relays 44 and fuses 46), the fan motor 40, the heat sinks 54, and the like, are housed in a unit case 92. The unit case 92 is a hollow rectangular parallelepiped overall and includes an upper case 94 and a lower case 96 that can be assembled and disassembled relative to each other in the vertical direction. The upper case 94 and the lower case 96 are formed, for example, from a synthetic resin. An intake hole 98 is provided on the upstream side (left side) of the unit case 92 in the airflow direction α of the fan motor 40, and an exhaust hole 100 is provided on the downstream side (right side) of the airflow direction α of the fan motor 40.

[0046] <Upper Case 94> The upper case 94 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 forms the front wall, an upper rear wall 104b that forms the rear wall, an upper left wall 104c that forms the left wall, and an upper right wall 104d that forms the right wall. The upper case 94 is formed with a size such that the left-right dimension is larger than the front-to-rear dimension.

[0047] In the first embodiment, the intake hole 98 and the exhaust hole 100 are both provided in the upper case 94. Furthermore, the suction path 88 in the unit case 92 communicates with the external space through the intake hole 98, and the air blow path 86 in the unit case 92 communicates with the external space through the exhaust hole 100.

[0048] In particular, in the first embodiment, the air intake hole 98 is configured to include a plurality of air intake slits 106. Each of these air intake slits 106 is formed at the left end of the upper bottom wall portion 102 and at the upper left wall portion 104c, penetrating each wall portion in the plate thickness direction. The air intake slits 106 are aligned in the front-rear direction in each of these wall portions.

[0049] Similarly, in the first embodiment, the exhaust hole 100 includes a plurality of exhaust slits 108. These exhaust slits 108 are formed at the right end of the upper bottom wall 102 and the upper right wall 104d, penetrating each wall in the thickness direction. The exhaust slits 108 are aligned in the front-to-rear direction in each wall. While the size of each exhaust slit 108 is not limited, it is preferable that the opening width dimension A (see FIG. 5 ) of each exhaust slit 108 be, for example, 3 mm or greater. Similarly, it is preferable that the opening width dimension of each intake slit 106 be, for example, 3 mm or greater.

[0050] <Lower Case 96> The lower case 96 has a generally box-like shape that opens upward and includes a bottom wall 110 and a lower peripheral wall 112 that protrudes upward from the outer periphery of the bottom wall 110. The lower case 96 is formed with a size that is larger in the left-right direction than in the front-to-rear direction. When the upper case 94 and the lower case 96 are assembled, the open end of the lower peripheral wall 112 and the open end of the upper peripheral wall 104 are butted together in the vertical direction, so that the upper opening of the lower peripheral wall 112 is covered by the upper case 94. The lower case 96 may, for example, hold a plurality of nuts (not shown) in a generally embedded state.

[0051] The method for fastening the upper case 94 and lower case 96 having the above-described shapes is not limited, but the upper case 94 and lower case 96 may be fastened, for example, by locking engagement using projections and recesses provided at corresponding positions on the upper peripheral wall portion 104 and the lower peripheral wall portion 112. Furthermore, the upper peripheral wall portion 104 and / or the lower peripheral wall portion 112 of the unit case 92 may be formed with insertion holes that penetrate each wall portion in the thickness direction, through which external electric wires (not shown) that are connected to the external connection portions 70, 72 and, if necessary, the monitoring and control portion 74 are inserted.

[0052] <Electrical Junction Box 30> The structure of the electrical junction box 30 is not limited, but its basic structure is similar to that of the circuit unit 10. That is, the electrical junction box 30 includes a circuit configuration including heat-generating components and a fan motor for cooling the heat-generating components, and these circuit configuration and fan motor are housed in a junction box case 114. As described above, the airflow direction β of the fan motor of the electrical junction box 30 is from right to left, and an intake hole 116 is provided on the upstream side (right side) of the airflow direction β in the junction box case 114, and an exhaust hole 118 is provided on the downstream side (left side) of the airflow direction β. Furthermore, the fan motor of the electrical junction box 30 may be electrically connected to the microcomputer 42 serving as a drive unit for the circuit unit 10, as described above, or may be driven by a drive unit (e.g., a microcomputer) (not shown) provided inside the electrical junction box 30, for example.

[0053] <Assembly of Circuit Unit 10> A specific example of a method for assembling the circuit unit 10 will now be described. Note that the method for assembling the circuit unit 10 is not limited to the embodiment described below.

[0054] First, the relays 44 and fuses 46 are bolted to the lower case 96 along with the current-carrying bus bars 64b to 64g and the heat-dissipating bus bars 80. Note that insulating and thermally conductive sheets 84 are provided in advance on the upper surface of the bottom wall portion 110 of the lower case 96 and / or the underside of the heat-dissipating portion 82 of each heat-dissipating bus bar 80. The heat sinks 54 are then superimposed on the portions 64a of the current-carrying bus bars 64d to 64g that cover the relays 44, with the insulating and thermally conductive sheets 62 interposed therebetween, and secured with bolts or the like. The fan motor 40 is then secured to the upper case 94 via the support frame 90. The monitoring and control unit 74 is then housed in the lower case 96, and the monitoring and control unit 74 is electrically connected to the fan motor 40 and the current-carrying bus bars 64. Next, the upper case 94 is brought close from above and fixed to the lower case 96, thereby completing the circuit unit 10.

[0055] The circuit unit 10 manufactured in this manner is housed in the housing body 24 together with the electrical junction box 30. Then, in the housing body 24 with the circuit unit 10 and the electrical junction box 30 provided therein, a plurality of battery cells 18 and a BMS board 22 are housed and electrically connected, and an upper opening 26 in the housing body 24 is covered with a lid 28, thereby forming the battery pack 12.

[0056] In this battery pack 12, for example, when the temperature sensor 36 in the monitoring and control unit 74 detects that the temperature inside the circuit unit 10 exceeds a predetermined temperature, a fan drive signal is sent from the microcomputer 42 to the fan motor 40, the drive power for the fan motor 40 is turned on, and the fan motor 40 is driven. Alternatively, when the current sensor 37 in the monitoring and control unit 74 detects that the magnitude of the current flowing through the circuit unit 10 exceeds a predetermined value, a fan drive signal is sent from the microcomputer 42 to the fan motor 40, the drive power for the fan motor 40 is turned on, and the fan motor 40 is driven. Then, for example, when the temperature sensor 36 detects that the temperature inside the circuit unit 10 has dropped below the predetermined temperature, or when the current sensor 37 detects that the magnitude of the current flowing through the circuit unit 10 has fallen below a predetermined value, or when a predetermined time has elapsed since the fan motor 40 was driven, a fan stop signal is sent from the microcomputer 42 to the fan motor 40, the drive power for the fan motor 40 is turned off, and the fan motor 40 is stopped.

[0057] Furthermore, when the fan motor of the electrical connection box 30 is electrically connected to the microcomputer 42, when it is detected that the temperature or current magnitude within the circuit unit 10 exceeds a predetermined value, a signal to drive the fan motor of the electrical connection box 30 is sent from the microcomputer 42, and the fan motor of the electrical connection box 30 can be driven along with the fan motor 40 of the circuit unit 10.

[0058] Here, for example, in the circuit unit 10, when the fan motor 40 is driven, air is drawn in through the intake holes 98, and an airflow in the airflow direction α is generated, causing the air to be exhausted through the exhaust holes 100. The air exhausted from the exhaust holes 100 is redirected by the inclined surfaces 34 of the exhaust direction restricting portions 32 and flows in a direction (forward) away from the battery cells 18. The air that has been redirected by the inclined surfaces 34 then flows inward in the left-right direction (to the left) between the circuit unit 10 and the front wall of the housing body 24, reaching the left-right center of the housing body 24. The air that has reached the left-right center of the housing body 24 is again drawn in through the intake holes 98 and circulates.

[0059] The circuit configuration section 38 in the circuit unit 10 includes the heat-generating components 14, namely, the relays 44 and fuses 46. These components, which generate heat when energized, are cooled by the air blown by the fan motor 40. Air passing through the circuit unit 10 increases in temperature when it comes into contact with the relays 44 and fuses 46. However, the inclined surface 34 of the exhaust direction restricting section 32 redirects the heated air away from the battery cells 18. This prevents air heated by the heat-generating components 14 (relays 44 and fuses 46) from flowing toward the battery modules 16 (battery cells 18), which could adversely affect the battery modules 16. The air exhausted through the exhaust hole 100 can also be cooled by contacting the wall of the housing main body 24 of the battery pack 12, allowing the air exhausted through the exhaust hole 100 to be drawn in through the intake hole 98 at a lower temperature. This allows for efficient cooling of the heat generated by the heat-generating components 14.

[0060] In particular, in the first embodiment, the relays 44, which generate a relatively large amount of heat, are arranged downstream of the fan motor 40 in the airflow direction α (airflow path 86), and the fuses 46, which generate a relatively small amount of heat, are arranged upstream of the fan motor 40 in the airflow direction α (suction path 88). Therefore, the temperature rise of the air caused by the fuses 46 upstream of the fan motor 40 is suppressed to some extent, and relatively low-temperature air can be blown downstream of the fan motor 40, where the relays 44, which generate a relatively large amount of heat, are arranged. This prevents relatively high-temperature air from being blown downstream of the fan motor 40, and allows stable heat dissipation from the relays 44, which generate a relatively large amount of heat. The above-described effect can also be achieved in the electrical junction box 30.

[0061] The circuit unit 10 of the first embodiment, which is configured as described above, includes a temperature sensor 36 and a current sensor 37 that monitor the temperature and current value within the circuit unit 10, and a microcomputer 42 that drives the fan motor 40 when these detected values ​​exceed predetermined values. This shortens the conductive path from the microcomputer 42 to the fan motor 40, thereby reducing the number of parts and assembly steps compared to, for example, connecting an electric wire or the like to the fan motor from outside the circuit unit. Furthermore, by shortening the conductive path from the microcomputer 42 to the fan motor 40, the fan motor 40 can be driven quickly. For example, when the detected values ​​of the temperature sensor 36 and the current sensor 37 exceed predetermined values, the fan motor 40 can be driven quickly to cool the heat-generating components 14 (relays 44 and fuses 46).

[0062] In particular, the fan motor 40 constitutes a driving component whose driving power is switched on and off based on the detected values ​​of the temperature sensor 36 and the current sensor 37. This allows for a simple structure for cooling the heat-generating component 14 by blowing air from the fan motor 40. For example, the driving power can be switched on when the detected values ​​of the temperature sensor 36 and the current sensor 37 exceed a predetermined value, and the driving power can be switched off when the detected values ​​of the temperature sensor 36 and the current sensor 37 fall below the predetermined value. The driving power can be switched on and off quickly by mounting the temperature sensor 36, the current sensor 37, and the microcomputer 42 on the same board 76. Furthermore, when the driving power is turned off after a predetermined time has elapsed after the fan motor 40 is driven, the temperature sensor 36 and the current sensor 37 only need to monitor whether they exceed the predetermined value, which prevents the monitoring and control unit 74 from becoming overly sophisticated.

[0063] Furthermore, the air supply path 86 and the suction path 88 each have a substantially constant cross-sectional area in the air supply direction α, and the cross-sectional areas of the paths 86, 88 are substantially equal to each other. As a result, air flows with a substantially constant cross-sectional area throughout the entire circuit unit 10, preventing local temperature increases in areas where air flow is difficult. Furthermore, the flowing air stably contacts the relays 44 in the air supply path 86 and the fuses 46 in the suction path 88, improving heat dissipation efficiency.

[0064] <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.

[0065] (1) In the above embodiment, the exhaust direction restricting portions 32, 32 are provided on both left and right wall portions of the housing body 24 of the battery pack 12 as separate entities from the circuit unit 10 and the electrical junction box 30. However, this is not limited to this. For example, as in the circuit unit 120 shown in FIG. 8 , the exhaust direction restricting portion 122 may be formed integrally with the unit case 92 of the circuit unit 120 or the junction box case 114 of the electrical junction box 30, or may be formed separately and then attached. Note that the exhaust direction restricting portion is not essential to the circuit unit according to the present disclosure. Furthermore, even when the exhaust direction restricting portion is provided in the battery pack as in the above embodiment, it is not limited to being provided on both left and right wall portions of the housing body. It may also be provided on the bottom wall portion of the housing body or on the lid.

[0066] (2) In the above embodiment, the circuit unit 10 having a structure according to the present disclosure is provided on the right side inside the battery pack 12, but the electrical junction box 30 provided on the left side inside the battery pack 12 may also have a structure according to the present disclosure. Note that in the present disclosure, only the circuit unit may be provided inside the battery pack, and the electrical junction box is not essential. In other words, the circuit unit according to the present disclosure may have a length dimension that allows it to be accommodated on the right side inside the battery pack as in the above embodiment, or may have a length dimension that spans substantially the entire length of the battery pack in the left-right direction.

[0067] (3) In the above embodiment, the intake hole 98 and the exhaust hole 100 are respectively configured by a plurality of intake slits 106 and exhaust slits 108, but this is not limited to this. The intake hole and the exhaust hole according to the present disclosure may be a single hole that penetrates the case in the thickness direction. Furthermore, these intake holes and exhaust holes are not limited to being provided in the upper case that constitutes the unit case, but may also be provided in the lower case, or in both the upper and lower cases.

[0068] (4) In the above embodiment, the fan motor 40 is provided in the left-right middle portion of the circuit unit 10, the relays 44 serving as the first heat-generating component are provided downstream of the fan motor 40 in the airflow direction α, and the fuse 46 serving as the second heat-generating component is provided upstream of the fan motor 40 in the airflow direction α. ​​However, this is not limited to this configuration. For example, in the circuit unit according to the present disclosure, the fan motor as the driving component may be provided at the most upstream side of the unit case in the airflow direction (the left end in the above embodiment), and the heat-generating component may be located downstream of the fan motor in the airflow direction and not located upstream of the fan motor in the airflow direction. Even in such a case, it is preferable that a fuse or the like with a relatively low heat generation be located upstream of the airflow path downstream of the fan motor in the airflow direction, and a relay with a relatively high heat generation be located downstream of the airflow path.

[0069] (5) The driving component whose driving power is switched on and off based on the detected values ​​of the temperature sensor or current sensor is not limited to a fan motor. Also, the driving component is not limited to a component intended to cool heat-generating components in a circuit unit.

[0070] (6) In the above embodiment, the monitoring and control unit 74 of the circuit unit 10 includes both the temperature sensor 36 and the current sensor 37 for monitoring the internal state of the circuit unit 10. However, at least one of the temperature sensor and the current sensor may be provided. Note that if the drive power for the drive component (fan motor 40) is turned on when the temperature sensor detects a temperature exceeding a predetermined temperature and turned off when the temperature sensor detects a temperature lower than the predetermined temperature, the temperatures at which the drive power is turned on and the drive power is turned off may be different. For example, the temperature at which the drive power is turned off may be lower than the temperature at which the drive power is turned on. Furthermore, if both a temperature sensor and a current sensor are provided, the drive power for the drive component may be turned on when the detected values ​​of both the temperature sensor and the current sensor exceed a predetermined value, or the drive power for the drive component may be turned off when the detected values ​​of both the temperature sensor and the current sensor are lower than the predetermined value.

[0071] DESCRIPTION OF SYMBOLS 10 Circuit unit (first embodiment) 12 Battery pack 14 Heat-generating component 16 Battery module 18 Battery cell 20 Housing 22 BMS board 24 Housing main body 26 Upper opening 28 Lid 30 Electrical connection box 32 Exhaust direction restricting section 34 Inclined surface 36 Temperature sensor 37 Current sensor 38 Circuit configuration section 40 Fan motor (driving component) 42 Microcomputer (driving section) 44 Relay (first heat-generating component) 46 Fuse (second heat-generating component) 48 Case main body 50 Terminal section 52 Insulating partition plate 54 Heat sink 56 Plate-shaped section 58 Heat sink 60 Gap 62 Insulating thermally conductive sheet 64 Current-carrying bus bar 64a Portion of current-carrying bus bar covering the top of the relay 64b to 64g Current-carrying bus bar 66 Terminal portion 68 Bolts 70, 72 External connection portion 74 Monitoring and control portion 76 Circuit board 78 Circuit board case 80 Heat dissipation bus bar 82 Heat dissipation portion 84 Insulating heat conductive sheet 86 Air supply path 88 Suction path 90 Support frame 92 Unit case 94 Upper case 96 Lower case 98 Air intake hole 100 Exhaust hole 102 Upper bottom wall portion 104 Upper peripheral wall portion 104a Upper front wall portion 104b Upper rear wall portion 104c Upper left wall portion 104d Upper right wall portion 106 Air intake slit 108 Exhaust slit 110 Bottom wall portion 112 Lower peripheral wall portion 114 Junction box case 116 Air intake hole 118 Exhaust hole 120 Circuit unit (another embodiment) 122 Exhaust direction restricting portion L Central axis α, β Air blowing direction

Claims

1. A circuit unit housed within a battery pack housing, comprising: a circuit configuration section including at least one of a temperature sensor and a current sensor; and a driving component driven by power from the circuit configuration section, wherein the circuit configuration section has a driving section that switches ON / OFF the driving power of the driving component, and the driving section switches ON / OFF the driving power of the driving component according to the detection value of at least one of the temperature sensor and the current sensor.

2. The circuit unit according to claim 1, wherein said circuit configuration includes a heat-generating component, and said driving component is a fan motor that promotes cooling of said heat-generating component.

3. The circuit unit according to claim 2, wherein the heat generating component includes a first heat generating component thermally connected to a heat sink, and the first heat generating component and the heat sink are arranged downstream of the fan motor in the air blowing direction of the fan motor.

4. A circuit unit as described in claim 3, 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.

5. A circuit unit as described in any one of claims 2 to 4, including a suction path extending from upstream of the fan motor toward the fan motor in the air blowing direction of the fan motor, and an air blowing path extending downstream from the fan motor, wherein the cross-sectional area in a direction perpendicular to the air blowing direction is constant throughout the entire area from the suction path to the air blowing path.

6. A circuit unit as claimed in any one of claims 1 to 4, wherein the driving unit turns on the driving power of the driving component when the detection value of the temperature sensor exceeds a predetermined temperature, and turns off the driving power of the driving component when the detection value of the temperature sensor falls below the predetermined temperature or when a predetermined time has elapsed since the driving component was driven.

7. A circuit unit as claimed in any one of claims 1 to 4, wherein the driving unit turns on the driving power of the driving component when the detection value of the current sensor exceeds a predetermined value, and turns off the driving power of the driving component when the detection value of the current sensor becomes smaller than the predetermined value or when a predetermined time has elapsed since the driving component was driven.

Images