Battery pack

Abstract

Battery pack including: a battery module (10); a metal housing (91) for storing the battery module (10) therein; a metal disc (70) provided separately from the metal housing (91), which is connected to the metal housing (91); a first group of switches (31, 32) which is mounted on the metal housing (91); a second switch group (33, 34, 35, 36) which is mounted on the metal disc (70).

Description

[0001] The present invention relates to a battery pack in which a battery module is contained within a metal housing.

[0002] As disclosed in patent document JP 2018 - 143 044 A, a battery pack is known to consist of a lithium battery, a switchboard, several switches and a housing.

[0003] In the battery pack disclosed in the aforementioned patent document, the multiple switches are mounted on the switchboard. Therefore, heat generated in one group of switches tends to be transferred to other switches.

[0004] Publication JP 2018-174 042 A shows a battery pack with a battery unit, a base accommodating the battery unit which has a heat-radiating wall, and switching devices which are able to transfer heat to the heat-radiating wall.

[0005] The heat-radiating wall and a tab are formed as a single unit, enabling them to transfer heat through a base wall. Heat generated by a switching device is transferred through a substrate to the heat-radiating wall of the base, the heat is transferred downwards through side walls, and furthermore, the heat is transferred from a side wall through the tab at a lower point to a vehicle side panel and dissipated to the outside.

[0006] The object of the present invention is to provide a battery pack that suppresses heat transfer among the multiple switches.

[0007] According to the present invention, a battery pack comprises a battery module, a metal housing for storing the battery modules therein, a metal disc which is connected to and separated from the metal housing, a first switch group which is mounted on the metal housing, and a second switch group which is mounted on the metal disc.

[0008] The metal housing and the metal disc are separate components. This results in increased thermal resistance at the connection point between the metal disc and the metal housing. Consequently, heat transfer between the first switch assembly, mounted on the metal housing, and the second switch assembly, mounted on the metal disc, is limited. The Fig. 1 is a circuit diagram showing a power supply system; the Fig. Figure 2 is a perspective exploded view of a battery pack; the Fig. Figure 3 is a perspective view of the battery pack; the Fig. 4 is a top view of a metal disc; the Fig. 5 is a side view of the metal disc; the Fig. Figure 6 is a top view of the battery pack; the Fig. Figure 7 is a cross-sectional view along line VII-VII in the Fig. 6.

[0009] The present invention is described with an embodiment which is illustrated in the drawings.

[0010] A battery pack 100 according to one embodiment and a power supply system 200 with the battery pack 100 are described with reference to the Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6 to Fig. 7 described. Overview of the power supply system

[0011] The power supply system 200 is mounted on a vehicle. The power supply system 200 has several devices mounted on the vehicle and the battery pack 100. One of the devices mounted on the vehicle is a storage battery 110. The battery pack 100 has an assembled battery (mounted battery pack) 10. The power supply system 200 forms a dual power supply system that includes the storage battery 110 and the assembled battery 10.

[0012] Another device mounted on the vehicle is a machine 140. The vehicle, equipped with the power supply system 200, has an idle stop function to stop the machine 140 when a predetermined stop condition is met, and to restart the machine 140 when a predetermined start condition is met.

[0013] As from the Fig. As can be seen in Figure 1, the power supply system 200 has a starter motor 120, a rotating electric machine 130, an electric load unit 150, an HL-ECU 160, which is a high-current electronic control unit serving as a main electronic control unit, and an MG-ECU 170, which is an electronic motor-generator control unit, in addition to the storage battery 110 and the machine 140. Each of the storage battery 110, the starter motor 120, and the electric load unit 150 is electrically connected to the battery pack 100 by a first wiring harness 210. The rotating electric machine 130 is electrically connected to the battery pack 100 by a second wiring harness 220.

[0014] The HL-ECU 160 and the MG-ECU 170 are electrically connected to the storage battery 110 and the assembled battery 10 of the battery pack 100 via wiring (not shown). Similarly, other ECUs (not shown) mounted on the vehicle are electrically connected to the storage battery 110 and the assembled battery 10 via wiring (not shown).

[0015] As described above, the power supply system 200 forms the dual power supply system using two power supply sources, namely the storage battery 110 and the assembled battery 10. Components of the power supply system

[0016] The storage battery 110 generates an electromotive voltage through a chemical reaction. The storage battery 110 has a greater electrical storage capacity than the assembled battery 10. The storage battery 110 is specifically a lead-acid storage battery. A lithium-ion storage battery, for example, can be used as the storage battery 110.

[0017] The starter motor 120 is provided to start the machine 140. The starter motor 120 is mechanically coupled to the machine 140 when the machine 140 needs to be started. A crankshaft of the machine 140 is rotated by the rotation of the starter motor 120. When the speed (number of revolutions) of the crankshaft of the machine 140 exceeds a predetermined speed, atomized fuel is injected from a fuel injector into a combustion chamber of the machine 140. At this time, a spark is generated by a spark plug. As a result, the fuel is burned, and the machine 140 begins to rotate on its own. Propulsive force for the vehicle is provided by the output power of the machine 140. When the machine 140 begins to rotate on its own, the mechanical connection between the starter motor 120 and the machine 140 is disengaged.

[0018] The rotating electric machine 130 performs a drive operation under load and generates electrical power. A power converter (not shown) is connected to the rotating electric machine 130. This power converter is electrically connected to the second wiring harness 220.

[0019] The power converter transforms direct current (DC) power, supplied by at least one of the storage batteries 110 and the assembled battery 10, into alternating current (AC) power. The DC power is then supplied to the rotating electric motor 130. As a result, the rotating electric motor 130 performs the driving function under load, acting as a motor.

[0020] The rotating electric machine 130 is connected to the machine 140. The rotating electric machine 130 and the machine 140 can mutually transfer rotational energy via a belt or similar device. The rotational energy generated by driving under the power of the rotating electric machine 130 is transferred to the machine 140. This improves the rotation of the machine 140. As a result, the driving of the vehicle is assisted. As described above, the vehicle equipped with the power supply system 200 has an idle-stop function. The rotating electric machine 130 not only has a function to assist the driving of the vehicle, but also a function to rotate the crankshaft as a motor when the machine 140 needs to be restarted.

[0021] The rotating electric machine 130 also has the function of generating electrical power by converting at least one of its rotational energy into the rotational energy of the machine 140 and the rotational energy of the vehicle's road wheels. The rotating electric machine 130 generates alternating current power by acting as a generator. This alternating current power is converted into direct current power by a power converter. This direct current power is supplied to each of the components from the battery pack 100, the storage battery 110, and the electrical load unit 150.

[0022] The engine 140 generates propulsive force for the vehicle through the combustion of fuel. As described above, when the engine 140 is to be started, the crankshaft is turned by the starter motor 120. However, when the engine 140 is to be restarted after having been stopped once by the idle-stop function, the crankshaft is turned by the rotating electric motor 130, provided that a predetermined starting condition is met.

[0023] The electrical load unit 150 has a first load 151 and a second load 152. The first load 151 includes vehicle-mounted devices such as seat heating, a blower fan, an electric compressor, interior lighting, and a headlight, which do not necessarily require a constant electrical power supply. The second load 152 includes vehicle-mounted devices such as an electric shift position sensor, power steering (EPS), an anti-lock braking system (ABS), a door lock, a navigation system, and an audio system, which require a constant electrical power supply. The second load 152 has the property of switching its operating state from an on state to an off state when the supply voltage falls below a reset threshold.The second load 152 has a device mounted on a vehicle that is more relevant to the driving of the vehicle than the first load 151.

[0024] It should be noted that the various devices mounted on the vehicle described above, which are present in the first load 151 and the second load 152, have only been mentioned as examples. Various devices mounted on the vehicle can be appropriately assigned to the first load 151 and the second load 152 according to a change in the system present in the vehicle or similar. For example, the EPS or the ABS can be assigned to the first load 151.

[0025] The HL-ECU 160 and the MG-ECU 170 are some of the various ECUs mounted on the vehicle. These different ECUs are electrically interconnected via a bus wiring system 161 to configure a network present in the vehicle. The combustion of the engine 140, driving under load, and the power generation of the rotating electric motor 130, among other things, are controlled by the combined control of the various ECUs. The HL-ECU 160 controls the battery pack 100. The MG-ECU 170 controls the rotating electric motor 130.

[0026] Although not shown, the power delivery system 200, in addition to the vehicle-mounted devices described above, has sensors for measuring physical quantities such as various voltages and currents, and vehicle information such as the amount of time an accelerator pedal is depressed and the throttle valve opening position. Detection signals from these various sensors are fed into the different ECUs. Overview of the battery pack

[0027] As from the Fig. As can be seen in Figure 1, the battery pack 100 has the assembled battery 10, a circuit board 20, a switching unit 30, a sensor unit 40, and a power supply busbar 50. As can be seen from the Fig. 2 and the Fig. As can be seen in Figure 3, the battery pack 100 has a metal disc 70, a housing 91, and a limiting disc 97. In the Fig. 2 and the Fig. The power supply busbar 50 is not shown in Figure 3.

[0028] The metal housing 91 is manufactured by aluminum injection molding. The metal housing 91 can also be manufactured by pressing iron or stainless steel. The metal housing 91, being made of a metal, exhibits a higher heat transfer efficiency (thermal conductivity) than a switchboard 21, which will be described later. For this reason, the metal housing 91 has a greater heat dissipation property than the switchboard 21.

[0029] The metal enclosure 91 has a bottom wall 93 and a side wall 94 that rises from the bottom wall 93. The side wall 94 is provided with an opening. A hard or metal cover is assembled with the metal enclosure 91. With the configuration described above, the opening provided in the side wall 94 is covered by the cover. The metal enclosure 91 and the cover form a receiving space between them. The battery pack 10, the circuit board 20, the switch unit 30, the sensor unit 40, the power supply busbar 50, the metal disc 70, and the limiting disc 97 are received in the receiving space.

[0030] The power supply busbar 50 is housed in a busbar housing made of an insulating resin material. This configuration forms a busbar module. The busbar module is housed within the receiving space. The busbar module is fastened to the metal housing 91 with screws.

[0031] The assembled battery 10 is smaller in size and lighter in weight than the storage battery 110. The assembled battery 10 exhibits a higher energy density than the storage battery 110.

[0032] The circuit board 20 has a switchboard 21 and a battery management unit (BMU) 22. Part of the switch unit 30 and the BMU 22 are mounted on the switchboard 21. The remainder of the switch unit 30 and the assembled battery 10 are electrically connected to the switchboard 21 via the power supply busbar 50. This configuration forms an electrical circuit for the battery pack 100. The sensor unit 40 is electrically connected to the circuit via electrically insulated wiring, a metal terminal, or similar means.

[0033] The electrical circuit of the battery pack 100 is electrically connected to external connection terminals located in the Fig. The external connection ports are indicated by double circles. They have a first external connection port 100a, a second external connection port 100b, a third external connection port 100c, and a fourth external connection port 100d.

[0034] The first external connection terminal 100a and the fourth external connection terminal 100d are electrically connected to the storage battery 110, the starter motor 120, and the load unit 150 via a first wiring harness 210. The second external connection terminal 100b is electrically connected to the rotating electric machine 130 via the second wiring harness 220. The third external connection terminal 100c, on the other hand, is mechanically and electrically connected to a body (chassis) of the vehicle.

[0035] As from the Fig. As can be seen in Figure 1, the first wiring harness 210 is divided into two wiring harnesses: one connecting the storage battery 110, the starter motor 120, and a first load 151, and the other connecting a second load 152. An end section of the first wiring harness 210, connecting the storage battery 110, the starter motor 120, and the first load 151, is connected to the first external connection terminal 100a. An end section of the first wiring harness 210, connecting the second load 152, is connected to the fourth external connection terminal 100d.

[0036] In this way, the first wiring harness 210 is connected to the first external connection 100a and the fourth external connection 100d of the battery pack 100. For this purpose, the first wiring harness 210 has two terminals. These two terminals are metal terminals with corresponding holes. The second wiring harness 220 is connected to the second external connection terminal 100b. Therefore, the second wiring harness 220 is a metal terminal with a hole. The first wiring harness 210 and the second wiring harness 220 are installed in the vehicle.

[0037] The first external connection terminal 100a, the fourth external connection terminal 100d, and the second external connection terminal 100b share a portion of the busbar housing. This shared section consists of a terminal block, a connecting screw, and a nut, all located within the busbar housing. The terminal block is made of an insulating resin. The connecting screw is embedded within the terminal block. The nut is connected to the connecting screw.

[0038] One end of the connecting screw is recessed in the terminal block. A shank section of the connecting screw protrudes from the terminal block. A through-hole of the power supply busbar 50 passes through the shank section of the connecting screw. Then, the nut is fastened to the shank section of the connecting screw. Next, the hole of the metal connector of the wiring harness passes through the shank section of the connecting screw. Another nut is fastened to a pointed end of the shank section of the connecting screw. As a result, a metal connector of the wiring harness is mechanically connected to the shank section of the connecting screw. At the same time, the metal connector is electrically connected to the power supply busbar 50.

[0039] The third external connection terminal 100c is a screw hole provided in the metal housing 91. This terminal is connected to the vehicle body via a screw or a wiring harness. As a result, the metal housing 91 is at ground potential, and the battery pack 100 is thus grounded to the vehicle body. Components of the battery pack

[0040] Next, individual components of the battery pack 100 will be described. In the following, three directions that are perpendicular to each other will be referred to as the X-direction, the Y-direction, and the Z-direction, as shown in the Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6 to Fig. The X-direction is a longitudinal direction. The Y-direction is a lateral direction. The Z-direction is a vertical direction, perpendicular or perpendicular to both the X-direction and the Y-direction.

[0041] The assembled battery 10 has several battery cells 14, as shown in the Fig. As can be seen in Figure 7, the components are connected in series. The assembled battery 10 also has a battery housing 11 that accommodates the multiple battery cells 14. These battery cells 14 are, in particular, lithium-ion storage batteries. Lithium-ion storage batteries generate an electromotive voltage through a chemical reaction. The generation of the electromotive voltage causes a current to flow through the battery cell 14. As a result, the battery cell 14 generates heat and produces a gas. As a result, the battery cell 14 expands. The battery cell 14 is not limited to the given example above. For example, the battery cell 14 could be a nickel-hydrogen auxiliary battery or another auxiliary battery such as an organic radical battery. The assembled battery 10 is a battery module.

[0042] As from the Fig. As can be seen in Figure 7, battery cell 14 has the shape of a rectangular parallelepiped. Battery cell 14 has two main surfaces oriented in the Z-direction. These two main surfaces have a larger area than the other four surfaces located around the perimeter of the two main surfaces. The length (thickness) between the two main surfaces is reduced. In this way, battery cell 14 has a thin, flat shape with a small thickness in the Z-direction.

[0043] The assembled battery 10 of the present embodiment comprises five battery cells 14. Three of these five battery cells 14 are arranged in such a way that they are stacked in the Z-direction to form a first cell stack. The remaining two battery cells 14 are arranged in such a way that they are stacked in the Z-direction to form a second cell stack. The first and second cell stacks are aligned in the X-direction. The arrangement of these five battery cells 14 is held by the battery housing 11. Fig. Figure 7 shows two battery cells 14 that form the second cell stack.

[0044] The battery housing 11 has a plastic casing and connection terminals for the battery cells 14. These connection terminals include a serial connection for connecting the five battery cells 14 in series. The serial connection terminal and the electrode terminals of the corresponding two battery cells 14 are brought into contact and welded together. As a result, the five battery cells 14 are connected in series.

[0045] In addition to the series connection terminals described above, the connection terminals have an output terminal 12, which is connected to a positive electrode terminal of battery cell 14 located at the highest potential among the five battery cells 14 connected in series, and a ground terminal 13, which is connected to a negative electrode terminal of battery cell 14 located at the lowest potential. The output terminal 12 is welded to the positive electrode terminal of battery cell 14 at the highest potential. The ground terminal 13 is welded to the negative electrode terminal of battery cell 14 at the lowest potential.

[0046] The highest potential battery cell 14 and the lowest potential battery cell 14 are present in the first cell stack. These two battery cells 14 are arranged at both ends of the three battery cells 14 stacked and arranged in the Z-direction within the first cell stack. The lowest potential battery cell 14 is positioned closer to the bottom wall 93 in the Z-direction than the highest potential battery cell 14.

[0047] The battery housing 11 is provided with holes for screws. Screw holes for fastening screws are formed in the metal housing 91. Screws are inserted through these holes and screw holes, and the screws are fastened in the screw holes. The battery housing 11 is thus attached to the metal housing 91.

[0048] The battery housing 11 is also attached to a metal housing 91 by two limiting discs 97. The two limiting discs 97 are positioned opposite the metal housing 91 in the Z-direction through the assembled battery 10. One of the two limiting discs 97 is arranged away from the second cell stack in the Z-direction. The other of the two limiting discs 97 is arranged separately from the first cell stack in the Z-direction.

[0049] Each of the two limiting discs 97 is provided with notches for screws. Screw holes for fastening screws are formed in the metal housing 91. Screws are passed through these holes and screw holes, and the screws are fastened to the screw holes. The limiting disc 97 is thereby fixed to the metal housing 91. The limiting disc 97 restricts the expansion of the battery housing 11 caused by the expansion of the battery cells 14.

[0050] As described above, the circuit board 20 includes the circuit board 21 and the BMU 22. The circuit board 21 is a printed circuit board in which a wiring pattern made of a conductive material is formed on an insulating board. A first supply line 23, a second supply line 24, a third supply line 25, and a fourth supply line 26 are formed as a wiring pattern on at least one surface and interior of the insulating board.

[0051] The circuit board 21 is attached to the metal housing 91 by screws or similar fasteners. Furthermore, the circuit board 21 is attached to the metal disc 70 by an insulating sheet 80. A mounting section 71 of the metal disc 70, which will be described later, is located opposite one of the two limiting discs 97, while being spaced apart in the Z-direction. The mounting bore 71 is aligned in the Z-direction with the second cell stack of the assembled battery 10 by one of the two limiting discs 97. The mounting section 71 and part of the circuit board 20 are separated in the X-direction from the highest potential battery cell 14 present in the first cell stack.

[0052] Electrically connected terminals are formed on the control panel 21. The terminals have a first internal terminal 28a, a second internal terminal 28b, a third internal terminal 28c, and a fourth internal terminal 28d. The electrical connection between the wiring pattern and the internal terminals will be described later following the description of the circuit configuration of the battery pack 100.

[0053] The switch unit 30 has a first switch 31, a second switch 32, a third switch 33, a fourth switch 34, a fifth switch 35, and a sixth switch 36. The first switch 31 and the second switch 32 are mounted on the metal housing 91. Each of the third switch 33 through the sixth switch 36 is mounted on a section of the switchboard 21 attached to the metal disc 70. Each of the third switch 33 through the sixth switch 36 is arranged in the Z-direction through the switchboard 21 and the insulating sheet 80 with the metal disc 70.

[0054] Each switch from the first switch 31 to the fourth switch 34 is a semiconductor switch. Specifically, each semiconductor switch is an N-channel MOSFET. Therefore, each switch from the first switch 31 to the fourth switch 34 is closed by an input of a high-level control signal. Each switch from the first switch 31 to the fourth switch 34 is opened by an input of a low-level control signal.

[0055] An IGBT or similar semiconductor switch can be used to form the first switch 31 up to the fourth switch 34. A diode is connected in parallel to the IGBT.

[0056] Switch 35 (fifth) and switch 36 (sixth) are mechanical relays. More precisely, switch 35 (fifth) and switch 36 (sixth) are normally closed electromagnetic relays. Therefore, switch 35 (fifth) and switch 36 (sixth) are opened by a high-level control signal input. Switch 35 (fifth) and switch 36 (sixth) are closed by a low-level control signal input. Specifically, switch 35 (fifth) and switch 36 (sixth) close when the high-level control signal input ceases.

[0057] Each switch, from the first switch 31 to the fourth switch 34, has at least one on / off section in which two MOSFETs are connected in series. The source electrodes of these two MOSFETs are connected together. The gate electrodes of the two MOSFETs are electrically independent of each other. The MOSFETs have parasitic diodes. The parasitic diodes of the two MOSFETs have interconnected anode electrodes. The gate electrodes are electrically connected to the circuit board 20.

[0058] Each switch, from the first 31 to the fourth 34, has multiple on / off sections. These multiple on / off sections are connected in parallel. In the third 33 and the fourth 34, the source electrodes of the two MOSFETs, which are connected in series and have multiple on / off sections, are connected together.

[0059] In the present embodiment, each switch from the first switch 31 to the fourth switch 34 has two opening and closing sections. The number of opening and closing sections and a connection type, such as a parallel connection and a series connection, are suitably determined according to the current, redundancy requirements, and similar factors.

[0060] Each of the opening and closing sections of the first switch 31 up to the fourth switch 34 has a resin section covering the two MOSFETs. The resin section has a rectangular parallelepiped shape. The resin sections of the first switch 31 and the second switch 32 have screw holes extending in the Z-direction.

[0061] As described above, the sensor unit 40 is electrically connected to the electrical circuit. The sensor unit 40 has sensor elements for detecting the respective states of the assembled battery 10 and the switch unit 30. The sensor unit 40 has a temperature sensor, a current sensor, and a voltage sensor as its sensor elements.

[0062] The sensor unit 40 records the temperature, current, and voltage of the assembled battery 10. The sensor unit 40 outputs the recorded values ​​to the BMU 22 as status signals for the corresponding battery 10.

[0063] The temperature sensor for detecting the temperature of the switch unit 30 is a temperature-sensing diode covered and protected by a resin section described above, along with the two MOSFETs connected in series. The current sensor for detecting the current of the switch unit 30 is a shunt resistor provided between the two MOSFETs connected in series.

[0064] In addition to the various types of sensors described above, sensor unit 40 has a submersion sensor. The submersion sensor has two electrodes facing each other. The presence of water between these two electrodes causes a current to flow between them. As a result, the resistance value between the two electrodes changes. This change in resistance is input as a status signal to the BMU 22. The BMU 22 detects the submersion of battery pack 100 based on whether the change in resistance value persists for a predetermined period.

[0065] The BMU 22 controls the switch unit 30 based on at least one of the status signals from the sensor unit 40 and an instruction signal from the HL-ECU 160.

[0066] As described above, each switch from the first switch 31 to the fourth switch 34 has multiple semiconductor switching elements. For example, when the opening and closing of the first switch 31 is controlled, the BMU 22 controls all semiconductor switching elements present in the first switch 31 so that they close or open simultaneously. For example, the BMU 22 simultaneously outputs the high-level control signal or the low-level control signal to the control electrodes (gate electrodes) of all semiconductor switching elements present in the first switch 31.

[0067] The BMU 22 can adjust the closing period of the semiconductor switch by intermittently outputting the control signal at a high level during the period when the semiconductor switch is closed. Specifically, the BMU 22 can control the semiconductor switch using a modulated pulse signal.

[0068] The BMU 22 determines the state of charge (SOC) of the assembled battery 10 and any abnormality of the switch unit 30 based on the status signal of the sensor unit 40. The BMU 22 outputs a signal to the HL-ECU 160 that transmits the state of charge and the abnormality (determination information).

[0069] The HL-ECU 160 determines the control of switch unit 30 based on the destination information input from the BMU 22 and the vehicle information input from the other various ECUs. The HL-ECU 160 outputs a command signal to the BMU 22 containing the specific control command for switch unit 30.

[0070] The BMU 22 controls the switch unit 30 based on the instruction signal from the HL-ECU 160. However, if the BMU 22 determines, based on the status signal from the immersion sensor, that the battery pack 100 is submerged, the BMU 22 stops, regardless of whether it outputs the control signal to the control unit 30. As a result, the electrical connection of the assembled battery 10 is severed.

[0071] If the BMU 22 determines that the temperature detected by the temperature-sensing diode has risen to approximately a guaranteed operating temperature of the switch unit 30, the BMU 22 limits the driving of the switch unit 30. Similarly, if the BMU 22 determines that the current detected by the shunt resistor has risen to the level of the guaranteed actuation current of the switch unit 30, the BMU limits the driving of the switch unit 30 in the same way. For example, if the semiconductor switch of the switch unit 30 is controlled by pulse-width modulation, the BMU 22 reduces the relative on-time of the semiconductor switch. This shortens the current supply period of the semiconductor switch. As a result, heat generation by the semiconductor switch is reduced.

[0072] The power supply busbar 50 is made of a conductive material such as aluminum or copper. The power supply busbar 50 is manufactured, for example, in the following exemplary manner. The power supply busbar 50 can be manufactured by bending a single flat disc. The power supply busbar 50 can be manufactured by joining several flat discs in one piece. The power supply busbar 50 can be manufactured by welding several flat discs. The power supply busbar 50 can be manufactured by pouring molten conductive material into a mold. The power supply busbar 50 can also be manufactured by a manufacturing process different from the one given above as an example.

[0073] The battery pack 100 has, as the power supply busbar 50, a first power supply busbar 51, a second power supply busbar 52, a third power supply busbar 53, and a fourth power supply busbar 54. The assembled battery 10, the circuit board 20, the first switch 31, the second switch 32, and the external connection terminals are electrically operationally connected via the multiple power supply busbars. In the Fig. 1 Each of these power supply busbars 51 to 54 is shown to be thicker than the supply line of the circuit board 20.

[0074] As described above, the metal housing 91 has a bottom wall 93 and a side wall 94. The bottom wall 93 has a bottom surface 93a oriented in the Z-direction. The side wall 94 rises from the bottom wall 93a in the Z-direction.

[0075] As from the Fig. As can be seen in Figure 2, the base wall 93 is formed with a first heat-radiating section 95 and a second heat-radiating section 96, which project locally towards the cover in the Z-direction. Each of the first heat-radiating section 95 and the second heat-radiating section 96 has a rectangular parallelepiped shape on the base surface 93a.

[0076] The first heat-radiating section 95 has a heat-radiating surface oriented in the Z direction. The first switch 31 is provided on the heat-radiating surface by a heat-radiating sheet 30a. The first switch 31 is screwed to the first heat-radiating section 95 in such a way that the heat-radiating sheet 30a is accommodated between the first switch 31 and the first heat-radiating section 95.

[0077] The second heat-radiating section 96 has a heat-radiating surface oriented in the Z direction. The second switch 32 is provided by the heat-radiating sheet 30a on the heat-radiating surface. The second switch 32 is screwed to the second heat-radiating section 96 in such a way that the heat-radiating sheet 30a is enclosed between the second switch 32 and the second heat-radiating section 96.

[0078] The first switch 31 and the second switch 32 form a first switch group. The metal housing 91 is a metal enclosure. The first heat-radiating section 95 and the second heat-radiating section 96 provide a mounting area for the first switch group.

[0079] As from the Fig. 2 and the Fig. As can be seen in Figure 3, the first heat-radiating section 95 and the second heat-radiating section 96 are aligned in the X direction. The first heat-radiating section 95 and the second heat-radiating section 96 are oriented in the Y direction towards the assembled battery 10. The first heat-radiating section 95 and the second heat-radiating section 96 are aligned with the second cell stack of the assembled battery 10 such that they are separated in the Y direction.

[0080] As from the Fig. As can be seen in Figure 6, the metal housing 91 is designed with a flange section 98 for attaching the battery pack 100 to the vehicle body. The metal housing 91 has four flange sections 98. Two of these four flange sections 98 are aligned in the Y direction. The remaining two flange sections 98 are also aligned in the Y direction. The two flange sections 98 aligned in the Y direction and the two remaining flange sections 98 aligned in the Y direction are separated from each other in the X direction.

[0081] One of the two flange sections 98, which are aligned in the Y direction, and the assembled battery 10 are aligned in the X direction. The other of the two flange sections 98, which are aligned in the Y direction, the first heat-radiating section 95 and the second heat-radiating section 96 are arranged in the X direction.

[0082] Therefore, the heat generated in the assembled battery 10 is simply radiated to the vehicle body through one of the two flange sections 98, which are aligned in the Y direction. The heat transferred from the first switch 31 and the second switch 32 to the first heat-radiating section 95 and the second heat-radiating section 96 is simply radiated to the vehicle body through the other of the two flange sections 98, which are aligned in the Y direction. In the following description, one of the two flange sections 98, which are aligned in the Y direction, is referred to as a first flange section 98a, and the other of the two flange sections 98, which are aligned in the Y direction, is referred to as the second flange section 98b.

[0083] The battery pack 100 of the present embodiment is provided under a seat of the vehicle. However, the placement of the battery pack 100 is not limited to the configuration given above. The battery pack 100 can, for example, be arranged in a space between a rear seat and a luggage compartment, a space between a driver's seat and a front passenger seat, or similarly. Battery pack circuit configuration

[0084] Next, a circuit configuration of the battery pack 100 is described. A pre-charge resistor 60, which consists of the Fig. As can be seen in Figure 1, it is connected to a circuit of the battery pack 100. The pre-charge resistor 60 is mounted on the switchboard 21.

[0085] The connection between each power supply busbar and each switch, as described below, is made by TIG welding. The connection between each power supply busbar and circuit board 20 is made by soldering. Each power supply busbar and each switch can be connected by laser welding.

[0086] As from the Fig. As can be seen in Figure 1, the first external connection terminal 100a and one end of the first switch 31 are electrically connected to each other by the first power supply bus bar 51. A portion of the first power supply bus bar 51 branches off as a first branch section 51a. The first branch section 51a of the first power supply bus bar 51 is electrically connected to the first internal terminal 28a of the switchboard 21.

[0087] The other end of the first switch 31 and the second external connection terminal 100b are electrically connected to each other via the second power supply busbar 52. A portion of the second power supply busbar 52 branches off as a second branch 52a. The second branch 52a of the second power supply busbar 52 is electrically connected to one end of the second switch 32. Another second branch 52b is connected to the fourth internal terminal 28d.

[0088] The other end of the second switch 32 and the positive electrode of the assembled battery 10 are electrically connected to each other via the third power supply busbar 53. A portion of the third power supply busbar 53 branches off as a third branch 53a. The third branch 53a of the third power supply busbar 53 is electrically connected to the second internal terminal 28b of the switchboard 21. The negative electrode of the assembled battery 10 is electrically connected to the third external connection terminal 100c. More precisely, the ground terminal 13 is screwed to the third external connection terminal 100c by a fuse.

[0089] The second internal terminal 28b and the first internal terminal 28a of the switchboard 21 are connected to each other by the first supply line 23. The third switch 33 and the fourth switch 34 are connected in series in the first supply line 23 in the sequence from the second internal terminal 28b to the first internal terminal 28a.

[0090] The third internal terminal 28c of the switchboard 21 is electrically connected to a midpoint (connection point) between the first internal terminal 28a and the fourth switch 34 in the first supply line 23 via the second supply line 24. The third internal terminal 28c is electrically connected to the fourth external connection terminal 100b via the fourth power supply busbar 54.

[0091] The fifth switch 35 is provided in the second supply line 24. A midpoint between the third inner terminal 28c and the fifth switch 35 and the second supply line 24 is connected to a midpoint between the third switch 33 and the fourth switch 34 in the first supply line 23.

[0092] One end of the third supply line 25 is connected to a midpoint between the first inner terminal 28a and the fourth switch 34 in the first supply line 23. The other end of the third supply line 25 is connected between the connection point between the fourth switch 34 and the third switch 33 of the first supply line 23 in the second supply line 24 and the fifth switch 35. The sixth switch 36 is provided in the third supply line 25.

[0093] A midpoint between the first inner terminal 28a and the fourth switch 34 in the first supply line 23 is electrically connected to the fourth inner terminal 28d via the fourth supply line 26. The pre-charge resistor 60 is provided in the fourth supply line 26.

[0094] As described above, the first switch 31, the second switch 32, the third switch 33, and the fourth switch 34 are connected sequentially in a ring. The midpoint between the first switch 31 and the second switch 32 is connected to the second external connection terminal 100b. The midpoint between the second switch 32 and the third switch 33 is connected to the assembled battery 10. The midpoint between the third switch 33 and the fourth switch 34 is connected to the fourth external connection terminal 100d. The midpoint between the fourth switch 34 and the first switch 31 is connected to the first external connection terminal 100a.

[0095] The first external connection port 100a and the fourth external connection port 100d are connected to each other by the fifth switch 35. The midpoint between the third switch 33 and the fourth switch 34 is connected to the first external connection port 100a by the fifth switch 35. Similarly, the first external connection port 100a and the fourth external connection port 100d are connected to each other by the sixth switch 36. The midpoint between the third switch 33 and the fourth switch 34 is connected to the first external connection port 100a by the sixth switch 36.

[0096] With the electrical connection configuration as described above, the electrical connection between the first external connection terminal 100a and the second external connection terminal 100b is controlled by controlling the opening and closing of the first switch 31. The electrical connection between the storage battery 110 and the rotating electric machine 130 is controlled by controlling the opening and closing of the first switch 31.

[0097] The electrical connection between the second external connection terminal 100b and the assembled battery 10 is controlled by controlling the opening and closing of the second switch 32. The electrical connection between the rotating electric machine 130 and the assembled battery 10 is also controlled by controlling the opening and closing of the second switch 32.

[0098] The electrical connection between the second inner terminal 28b and the third inner terminal 28c is controlled by controlling the opening and closing of the third switch 33. Specifically, the electrical connection between the assembled battery 10 and the second load 152 is controlled by controlling the opening and closing of the third switch 33.

[0099] The electrical connection between the first internal terminal 28a and the third internal terminal 28c is controlled by controlling the opening and closing of the fourth switch 34. The electrical connection between the storage battery 110 and the second load 152 is also controlled by controlling the opening and closing of the fourth switch 34.

[0100] The electrical connection between the first internal terminal 28a and the third internal terminal 28c is also controlled by controlling the opening and closing of at least one of the fifth switch 35 and the sixth switch 36. The electrical connection between the storage battery 110 and the second load 152 is also controlled by controlling the opening and closing of at least one of the fifth switch 35 and the sixth switch 36.

[0101] The first external connection terminal 100a and the second external connection terminal 100b are electrically connected to each other via the pre-charge resistor 60. As described above, the second wiring harness 220 is connected to the second external connection terminal 100b. A power converter (not shown) is connected to the second wiring harness 220.

[0102] The power converter has a smoothing capacitor with a large capacitance. The smoothing capacitor is used in a charged state. The smoothing capacitor is charged by supplying electrical power from the storage battery 110.

[0103] The first wiring harness 210 and the second wiring harness 220 are connected to the battery pack 100. As a result, an electrical charge is supplied from the storage battery 110 through the pre-charge resistor 60 to the smoothing capacitor. In this way, the amount of current flowing from the storage battery 110 to the smoothing catalyst is limited to a sudden increase due to the charging through the pre-charge resistor 60.

[0104] As described above, the connection destinations of the first switch 31 to the sixth switch 36 are different from each other. Therefore, the current supply quantities from the first switch 31 to the sixth switch 36 are also different. The heat generation quantities from the first switch 31 to the sixth switch 36 are also different from each other.

[0105] In particular, the first switch 31 and the second switch 32 are electrically connected to the rotating electric machine 130 at positions outside the switchboard 21 of the circuit board 20. For this reason, the first switch 31 and the second switch 32 have a larger current supply than the other four switches 33 to 36, which are located inside the switchboard 21 of the circuit board 20, with respect to a time average, and the amount of heat generated tends to increase. Therefore, it is necessary to suppress the temperature rise of the first switch 31 and the second switch 32. For this reason, the first switch 31 and the second switch 32 are located in the metal housing 91, which has a higher heat dissipation property than the switchboard 21.

[0106] However, with the preceding increase in the amount of current supplied, the amount of current supplied to each of the third switch 33 up to the sixth switch 36 also increases, and the amount of heat generated also increases. Therefore, it is also necessary to suppress the temperature rise from the third switch 33 to the sixth switch 36. To address the requirements described above, the switchboard 21, on which the third switch 33 to the sixth switch 36 are mounted, is mounted on the metal disc 70 in the battery pack 100. metal disc

[0107] Next, the metal disc 70 is described. The metal disc 70 is manufactured by aluminum injection molding in the same way as the metal housing 91. The metal disc 70 can also be manufactured by pressing iron or stainless steel. The metal disc 70 has a higher heat transfer efficiency than the switchboard 21. Therefore, the metal disc 70 has a higher heat distribution (thermal conductivity) than the switchboard 21.

[0108] As from the Fig. 4 and the Fig. As can be seen in Figure 5, the metal disc 70 has a mounting section 71, a main connection section 72, and an auxiliary connection section 73. The mounting section 71 has a mounting surface 71a oriented in the Z-direction. The mounting section 71 is provided with screw holes 71b for screwing the control panel 21 to the mounting surface 71a. Corresponding through holes are formed in the control panel 21. The screw hole 71b opens on the mounting surface 71a. The screw hole 71b extends in the Z-direction from the mounting surface 71a to a rear surface on the back of the mounting section 71. However, the screw hole 71b is not open on the rear surface. The screw hole 71b does not penetrate the control panel 21.

[0109] In the present embodiment, three screw holes 71b are formed in the mounting section 71. Two of these three screw holes 71b are aligned in the X-direction and spaced apart from each other. The remaining screw hole 71b is separated in the Y-direction from the center point of the two screw holes 71b that are spaced apart in the X-direction. With the configuration described above, the imaginary line segment connecting the openings of the mounting surfaces 71a of the three screw holes 71b forms an isosceles triangle.

[0110] The insulating sheet 80 is positioned on the mounting surface 71a of the mounting section 71. The switchboard 21 is positioned on the insulating sheet 80. Each through-hole of the switchboard 21 is aligned with the opening of the screw hole 71b in the Z-direction. In this position, the shank of the first connecting screw 74 passes through the through-hole and the screw hole 71b. The first connecting screw 74 is then secured to the through-hole and the screw hole 71b. As a result, the switchboard 21 is firmly connected to the mounting section 71.

[0111] A wall section is formed on the rear surface of the mounting surface 71a such that it extends from the mounting surface 71a in the Z-direction. The wall section has a tubular shape around the Z-direction. Each of the connecting sections 72 and the auxiliary connecting sections 73 extends from the wall section in such a way that it is separated from the mounting section 71. As shown in particular in the Fig. 4 and the Fig. As shown in Figure 5, the connecting sections 72 and the auxiliary connecting section 73 extend in the opposite direction in the Y-direction through the assembly section 71.

[0112] The metal disc 70 of the present embodiment has two connecting sections 72. These two connecting sections 72 are aligned in the X direction. A notch 72a for guiding the shank section of the second connecting screw 75 is formed at the tip of each of the two connecting sections 72.

[0113] The metal disc 70 of the present embodiment has an auxiliary connecting section 73. The auxiliary connecting section 73 is oriented such that it is separated from one of the two connecting sections 72 in the Y-direction. A through-hole 73a for guiding the shank section of the second connecting screw 75 is formed at the tip of the auxiliary connecting section 73. The auxiliary line segment connecting the two notches 72a described above and a through-hole 73a forms a triangle. The triangle and the mounting surface 71a are oriented in the Z-direction.

[0114] A cross-sectional area perpendicular to the direction of extension of the auxiliary connection section 73 is smaller than a cross-sectional area perpendicular to the direction of extension of each of the two connection sections 72. Therefore, the auxiliary connection section 73 has a higher thermal resistance than that of the two connection sections 72.

[0115] It is noted that the thermal resistance of the auxiliary connection section 73 may be higher than the total thermal resistance value, which is the sum of the thermal resistances of each of the multiple connection sections 72. In this case, the auxiliary connection section 73 may have a lower thermal resistance than a single connection section 72. Furthermore, the number of auxiliary connection sections 73 is not limited to one but may be a multiple. In this case, it is possible that the total thermal resistance value provided by adding the thermal resistances of the multiple auxiliary connection sections 73 is higher than the total thermal resistance value obtained by adding the thermal resistance values ​​of the multiple connection sections 72.

[0116] A first screw hole 91b and a second screw hole 91c for fastening the metal disc 70 by means of the second connecting screws 75 are formed in the metal housing 91. Each opening of the first screw hole 91b and the second screw hole 91c is oriented in the Z-direction. The first screw hole 91b is formed in the side wall 94 of the metal housing 91. The second screw hole 91c is formed in the bottom wall 93 of the metal housing 91.

[0117] In the present embodiment, two first screw holes 91b are formed in the side wall 94. A second screw hole 91c is formed in the bottom wall 93. The two first screw holes 91b are separated in the X and Y directions according to the positional ratio of the corresponding notches 73a of the two connecting sections 92. The two first screw holes 91b and the second screw hole 91c are separated in the X and Y directions according to the positional ratio between the two notches 72a and the through hole 73a.

[0118] The notch 72a of the main connecting section 72 is aligned with the opening of the first screw hole 91b in the Z-direction. Additionally, the through hole 73a of the auxiliary connecting section 73 is aligned with the opening of the second screw hole 91c in the Z-direction. In this configuration, the shank of the second connecting screw 75 passes through the notch 72a and the through hole 73a. The second connecting screw 75 is secured by the first screw hole 91b and the second screw hole 91c. As a result, the metal washer 70 is firmly connected to the metal housing 91.

[0119] At a position (connection section) where the main connection section 72 and the first screw bore 91b are connected by the second connecting screw 75, the thermal resistance is higher than that of the main connection section 72 and the metal housing 71 due to the connection resistance. For this reason, heat transfer between the main connection section 72 and the metal housing 71 is less likely to occur compared to a configuration in which the main connection section 72 and the metal housing 91 are integrated.

[0120] Similarly, at a position (connection section) where the connection section 73 and the second screw hole 91c are connected by the second connecting screw 95, the thermal resistance is higher than that of the connection section 73 and the metal housing 91 due to the connection resistance. For this reason, heat transfer between the connection section 73 and the metal housing 91 is less likely to occur compared to a configuration in which the connection section 73 and the metal housing 91 are integrated. Screw hole position

[0121] A section in the side wall 94, in which one of the first two screw holes 91b is formed, is oriented in the Y-direction towards the assembled battery 10. This section is aligned in the Y-direction with the first heat-radiating section 95 (second heat-radiating section 96) through the assembled battery 10.

[0122] A section in the side wall 94, on which the other of the screw holes 91b is formed, is oriented in the X direction towards the assembled battery 10. This section is arranged between the first screw hole 91b and the first heat-radiating section 95 (second heat-radiating section 96) in the Y direction.

[0123] The location where the second screw hole 91c is formed in the bottom wall 93 is arranged between the assembled battery 10 and the first heat-radiating section 95 (second heat-radiating section 96) in the Y direction.

[0124] Due to the positional relationship described above, one of the first two screw holes 91b and the second screw hole 91c are aligned in the Y-direction by the assembled battery 10. The other of the first two screw holes 91b is located between one of the first two screw holes 91b and the second screw hole 91c in the Y-direction.

[0125] The location of the first two screw holes 91b in the side wall 94 is further away from the first heat-radiating section 95 and the second heat-radiating section 96 in the Y-direction than the mounting section 71 is in the Y-direction. The location of the second screw hole 91c in the bottom wall 93 is closer to the first heat-radiating section 95 and the second heat-radiating section 96 than the mounting section 71 in the Y-direction.

[0126] Therefore, the surface creep distance between each of the first two screw holes 91b and the first heat-radiating section 95 (second heat-radiating section 96) in the surface creep direction along the surface of the metal housing 91 is greater than the surface creep distance between the second screw hole 91c and the first heat-radiating section 95 (second heat-radiating section 96). The thermal resistance between each of the first two screw holes 91b and the first heat-radiating section 95 (second heat-radiating section 96) in the heat transfer path of the metal housing 91 is higher than that between the second screw hole 91c and the first heat-radiating section 95 (second heat-radiating section 96). As described above, the auxiliary connection section 73 has a higher thermal resistance than the main connection section 72.

[0127] Due to the position ratio and thermal resistance described above, it is less likely that the heat transferred from the first switch 31 and the second switch 32 to the first heat-radiating section 95 and the second heat-radiating section 96 will be thermally transferred to the first screw hole 91b and the second screw hole 91c.

[0128] As described above, the first heat-radiating section 95 and the second heat-radiating section 96 are aligned with a second flange section 98b in the X-direction. Therefore, the heat transferred from the first switch 31 and the second switch 32 to the first heat-radiating section 95 and the second heat-radiating section 96 is simply radiated to the vehicle body via the second flange section 98b. The heat transferred from the third switch 33 to the sixth switch 36 to the second screw hole 91c through the mounting section 71, the auxiliary connection section 73, and the second connecting screw 75 is also simply transferred to the vehicle body via the second flange section 98b.

[0129] The location where each of the first two screw holes 91b is formed in the side wall 94 is closer to the side of the first flange section 98a than to the side of the second flange section 98b. Therefore, the heat transferred from the third switch 33 to the sixth switch 36 to the first screw hole 91b via the mounting section 72 and the second connecting screw 75 is simply distributed through the first flange section 98a to the vehicle body. Connection state of the metal disc

[0130] As from the Fig. 6 and the Fig. As can be seen in Figure 7, the assembly section 71 is in a state where the metal disc 70 is attached to the metal housing 91 by the second connecting screw 75, and the assembly section 71 is aligned with the second cell stack of the battery pack 10 by one of the two limiting discs 97 in the Z-direction. The switchboard 21 is mounted to the mounting surface 71a of the assembly section 71 by the insulating sheet 80. The assembly section 71 and one of the two limiting discs 97 are separated from each other in the Z-direction.

[0131] The third switch 33 through the sixth switch 36 are arranged in a protruding area (projecting area) that extends onto the mounting surface 71a along the Z-direction in the switchboard 21. In this configuration, the third switch 33 through the sixth switch 36 are mounted through the switchboard 21 and the insulating sheet 80 on the mounting section 71. Due to this mounting configuration, the heat generated by the third switch 33 through the sixth switch 36 is easily transferred through the switchboard 21, the insulating sheet 80, and the metal disc 70 to the metal housing 91. The third switch 33 and the sixth switch 36 form a second switch group.

[0132] Switch 35 (fifth) and Switch 36 (sixth) are supplied with current when the vehicle is parked or stopped. Switch 35 and Switch 36 are not supplied with current when the vehicle is moving. In contrast, Switch 33 (third) and Switch 34 (fourth) are supplied with current when the vehicle is moving. Therefore, Switch 35 and Switch 36 receive less current over time than Switch 33 and Switch 34, and consequently generate less heat. Switch 33 and Switch 34, on the other hand, have a higher average current supply over time than Switch 35 and Switch 36, and consequently generate more heat.Due to the difference in the amount of heat generated, the third switch 33 and the fourth switch 34 can be arranged in the projection area of ​​the switchboard 21 as described above, and the fifth switch 35 and the sixth switch 36 can be arranged outside the projection area. Operational impacts

[0133] Next, the operational effect of the battery pack 100 will be described. As described above, the metal disc 70, which is a separate element, is firmly connected to the metal housing 91 by two connecting screws 75. Therefore, the thermal resistance at the connection point between the metal housing 91 and the metal disc 70 is increased. Consequently, heat transfer between the first switch 31 and the second switch 32, which are mounted on the metal housing 91, and the third switch 33 through the sixth switch 36, which are mounted on the metal disc 70, is suppressed.

[0134] The heat transfer from the first switch 31 and the second switch 32 to the third switch 33 to the sixth switch 36 limits the temperature of the third switch 33 to the sixth switch 36 before it rises. The heat transfer from the third switch 33 to the sixth switch 36 to the first switch 31 and the second switch 32 limits the temperature of the first switch 31 and the second switch 32 before it rises.

[0135] Furthermore, the third switch 33 through the sixth switch 36 are mounted on the metal disc 70 by the switchboard 21 and the insulating sheet 80. The metal disc 70 is fastened to the metal housing 91 by the second connecting screw 75. According to this configuration, for example, the heat generated by the third switch 33 through the sixth switch 36 is simply transferred to the metal housing 91, compared to the configuration in which the third and sixth switches are connected to the housing only by the switchboard. As a result, a reduction in the heat dissipation efficiency from the third switch 33 to the sixth switch 36 is prevented.

[0136] The third switch 33 up to the sixth switch 36 are arranged in the area (projection area) that is projected onto the mounting surface 71a along the Z-direction in the switchboard 21. This makes it easier for the heat generated by the third switch 33 to the sixth switch 36 to be transferred to the metal disk 70, compared to the configuration in which the third switch to the sixth switch are arranged outside the projection area.

[0137] The assembled battery 10 is aligned with the first heat-radiating section 95 and the second heat-radiating section 96 in the Y direction. The mounting section 71 is oriented in the Z direction towards the assembled battery 10. The auxiliary connecting section 73, extending from the mounting section 71, is fastened to the second screw hole 91c, located between the assembled battery 10 and the first heat-radiating section 95 (second heat-radiating section 96), by the second connecting screw 75. The main connecting section 73, extending from the mounting section 71 in the opposite direction to the auxiliary connecting section 73, is fastened to the first screw hole 91b, formed in the section of the side wall 94 that faces the assembled battery 10 in the X and Y directions, by the second connecting screw 75.

[0138] According to this configuration, the heat transferred from the first switch 31 and the second switch 32 to the first heat-radiating section 95 and the second heat-radiating section 96 can be restricted to being transferred via the main connection section 72 to the mounting section 71. Therefore, the heat transfer from the first switch 31 and the second switch 32 to the third switch 33 up to the sixth switch 36 is restricted.

[0139] The auxiliary connection section 73 has a higher thermal resistance than either of the two connection sections 72. Therefore, the transfer of heat from the first switch 31 and the second switch 32 to the first heat-radiating section 95 and the second heat-radiating section 96 through the auxiliary connection section 73 to the assembly section 71 is restricted. Specifically, the transfer of heat from the third switch 33 to the sixth switch 36 to the first heat-radiating section 95 and the second heat-radiating section 96 through the auxiliary connection section 73 is restricted. The heat transfer between the first switch 31 and the second switch 32, and between the third switch 33 and the sixth switch 36 through the auxiliary connection section 73, is also restricted.

[0140] As described above, the assembly section 71 is connected to the metal housing 91 not only by the main connection section 72 but also by the auxiliary connection section 73. It is noted that the connection between the metal disc 70 and the metal housing 91 becomes unstable.

[0141] The assembled battery 10 is mounted on the bottom wall 93 of the metal housing 91. The mounting section 71 is aligned with the bottom wall 93 in the Z-direction through the assembled battery 10. According to this configuration, the increase in the physical properties of the battery pack 100 in the X- and Y-directions is limited compared to a configuration in which the mounting section and the bottom wall are not aligned with each other in the Z-direction.

[0142] One of the two suppression discs 97 is positioned between the assembly section 71 and the assembled battery 10. According to this configuration, the heat generated in the assembled battery 10 is transferred more readily to the suppression disc 97 than to the assembly section 71. Conversely, the heat generated by the third switch 33 to the sixth switch 36 is transferred more readily to the suppression disc 97 than to the assembled battery 10. Therefore, heat transfer between the assembled battery 10 and the third switch 33 to the sixth switch 36 is suppressed.

[0143] The mounting section 71 is oriented towards the second cell stack, which is shorter in the Z-direction than the first cell stack in the assembled battery 10, and is spaced in the Z-direction. Additionally, the mounting section 71 is oriented towards the first cell stack, which is longer in the Z-direction than the second cell stack in the battery pack 10, and is spaced in the X-direction. According to this configuration, the rise in the physics of the battery pack 100 in the Z-direction is suppressed compared to a configuration in which the mounting section is separated from the first cell stack and oriented in the Z-direction.

[0144] As described above, the first screw holes 91b, which are secured by the second connecting screws 75 of the main connecting section 72, are formed in the side wall 94. Accordingly, the heat generated by the third switch 33 to the sixth switch 36 is transferred through the switchboard 21, the insulating sheet 80, the mounting section 71, the main connecting section 72, and the second connecting screw 75 to the side wall 94. This causes the temperature of the side wall 94 to rise. This temperature increase causes an airflow along the surface of the side wall 94. The air moves heat along the surface of the side wall 94. This air movement improves the heat distribution from the side wall 94. As a result, the radiation of the heat generated by the third switch 33 to the sixth switch 36 is improved.

[0145] Although the present invention has been described with reference to the preferred embodiment, the present invention is not limited to the embodiment described above, but can be implemented by various modifications without departing from the spirit of the present disclosure. First modification

[0146] In the embodiment described above, the metal disc 70 is shown by way of example having the auxiliary connection section 73. However, the metal disc 70 need not have the auxiliary connection section 73. Second modification

[0147] In the embodiment described above, the metal disc 70 is shown by way of example having two connecting sections 72. However, the number of connecting sections 72 present in the metal disc 70 is not limited to the example given above. The metal disc 70 can have only one, or three or more connecting sections 72. Third modification

[0148] In the embodiment described above, the third switch 33 through the sixth switch 36 are shown, by way of example, as mounted on the mounting section 71 of the metal disc 70 by means of the insulating sheet 80 and the switchboard 21. However, at least one of the switches from the third switch 33 to the sixth switch 36 can be mounted on the mounting section 71 by means of the insulating sheet 80. Additionally, at least one of the switches from the third switch 33 to the sixth switch 36 can be mounted directly on the mounting section 71. Other modifications

[0149] In the embodiment described above, nothing is described about a section that is screwed to the metal housing 91 in the battery housing 11. The section that is screwed to the metal housing 91 in the battery housing 11 is a projection 15 that protrudes locally laterally from the battery housing 11, for example from the Fig. As can be seen in Figure 2, a cylindrical collar 16, opening in the X direction, is embedded in the projection 15. Screws are passed through the collar 16. This screw is then attached to the metal housing 91 such that the collar 16 and the screw are in contact.

[0150] The collar 16 is made of a metal. The collar 16 has a higher conductivity than the resin material that forms the battery housing 11. For this reason, the collar 16 actively conducts heat to the metal housing 91 via the screw that passes through its cavity.

[0151] Four projections 15, into which the collar 16 is embedded, are formed in the battery housing 11. Two of these four projections 15 are arranged side by side with the two cell stacks. Two projections 15 are arranged in such a way that they are separated from each other in a longitudinal direction (X-direction). Fig. 2 the two projections 15 are shown arranged side by side with the second cell stack in a lateral direction (Y-direction).

[0152] Furthermore, the remaining two of the four projections 15 are arranged side by side with the first cell stack. Two projections 15 are also arranged in such a way that they are separated from each other longitudinally.

[0153] The first cell stack has three battery cells 14. These three battery cells 14 are arranged in a vertical direction (Z-direction). Therefore, the battery cell 14 located in the middle of the three vertically oriented battery cells 14 tends to have a lower heat dissipation efficiency than the two battery cells 14 located on either side.

[0154] To improve the heat distribution performance of the middle battery cell 14, which tends to be low in heat distribution performance, the protrusions 15 with the embedded metal collar 16 are arranged side by side in the lateral direction inside the middle battery cell 14.

[0155] The length of the projection 15 in the vertical direction is longer than the length (thickness) of the battery cell 14 in any vertical direction. The projection 15 is arranged in the lateral projection plane of the middle battery cell 14. Furthermore, the projection 15 is also arranged in the lateral projection plane of at least one of the two battery cells 14 located at the end.

[0156] Since the projection 15 and the battery cell of the first cell stack are aligned in the lateral direction, any heat generated in the battery cell 14 of the first cell stack is simply transferred to the metal collar 16 embedded in the projection 15.

[0157] The heat transferred to the collar 16 is distributed to the metal housing 91 by screws that pass through the collar 16.

[0158] In the embodiment described above, the metal disc 70 is, by way of example, screwed to the metal housing 91. However, the method for joining the metal disc 70 and the metal housing 91 is not limited to the example given above. For example, pressure contact or welding can be used to join the metal disc 70 to the metal housing 91. In any joining method, the thermal resistance of the connecting section between the metal disc 70 and the metal housing 91, which are separate bodies, is higher than that of the main connecting section 72 or the metal housing 91 due to the connection resistance.

[0159] In the embodiment described above, the assembled battery 10 is shown by way of example comprising five battery cells 14. However, the assembled battery 10 is not limited to the example described above, insofar as it comprises multiple battery cells. Likewise, the number of cell stacks can be one or more than two instead of two. Furthermore, the cell stack can be configured by arranging the battery cells in the X-direction.

[0160] In the embodiment described above, the vehicle on which the power supply system 200 is mounted is shown, by way of example, as having an idle-stop function. However, the vehicle on which the power supply system 200 is mounted is not limited to the example given above. For example, the vehicle can be a hybrid vehicle or an electric vehicle. In this case, the starter 120 and the rotating electric machine 130, which are shown in the embodiment described above, are replaced by a motor-generator.

[0161] It should be noted that the ECU described in this description is also referred to as a computer or a microcomputer. The ECU provides a control system for controlling a control target. At least one of the functions described in this description is provided by an ECU configured to provide that function.

Claims

[1] Battery pack containing: a battery module (10); a metal housing (91) for storing the battery module (10) therein; a metal disc (70) provided separately from the metal housing (91), which is connected to the metal housing (91); a first group of switches (31, 32) which is mounted on the metal housing (91); a second switch group (33, 34, 35, 36) which is mounted on the metal disc (70). [2] Battery pack according to claim 1, wherein: the metal disc (70) has a mounting section (71) for mounting the second switch group (33, 34, 35, 36) on it and a main connection section (72) for connecting the mounting section (71) to the metal housing (91); the assembly section (71) and a mounting area for mounting the first switch group (31, 32) in the metal housing (91) in a lateral direction (Y) along a mounting surface (71a) of the second switch group in the assembly section (71) are separated; the main connecting section (72) is connected to a section which is spaced in the lateral direction (Y) from the mounting area in the metal housing (91) by the mounting section (71). [3] Battery pack according to claim 2, wherein: the metal disc (70) has an auxiliary connecting section (73) in addition to the mounting section (71) and the main connecting section (72) to connect the mounting section (71) to the metal housing (1); the auxiliary connection section (73) is connected to the metal housing (91) at a connection position which is closer to the mounting area in the lateral direction (Y) than a connection position of the main connection section (72) on the metal housing (91); the auxiliary connection section (73) has a higher thermal resistance than the main connection section (72). [4] Battery pack according to claim 3, wherein: a number of main connection sections (72) is greater than a number of auxiliary connection sections (73). [5] Battery pack according to any one of claims 2 to 4, wherein: the battery module (10) is mounted on a bottom wall (93) of the metal housing (91); and the assembly section and the floor wall (93) are aligned and spaced apart in a vertical direction (Z) that lies perpendicular to the assembly surface (71a). [6] Battery pack according to claim 5, wherein: the battery module (10) is arranged in the vertical direction (Z) between the bottom wall (93) and the mounting section; and the battery module (10) is spaced away from the mounting section in the vertical direction (Z). [7] Battery pack according to claim 6, wherein: the battery module (10) has several cell stacks that have different lengths in the vertical direction (Z); and the assembly section is directed towards a cell stack which is smallest in the vertical direction (Z) among the several cell stacks through a space in the vertical direction (Z), and the assembly section is directed towards a cell stack which is largest in the vertical direction (Z) among the several cell stacks through a space in a longitudinal direction (X) which is perpendicular to both the vertical direction (Z) and the lateral direction (Y). [8] Battery pack according to claim 7, further comprising: a limiting disc (97) which is provided in the vertical direction (Z) between the battery module (10) and the mounting section; and the assembly section and the limiting disc (97) are spaced apart in the vertical direction (Z). [9] Battery pack according to any one of claims 2 to 8, wherein: the metal housing (91) has a bottom wall (93) on which the battery module (10) is mounted, and a side wall (94) that rises from the bottom wall (93); and the main connecting section (72) is connected to the side wall (94). [10] Battery pack according to any one of claims 1 to 10, wherein: the first switch group (31, 32) has a first switch (31) and a second switch (32); the first switch (31) is connected between a storage battery (110) and a rotating electric machine (130) connected to a machine (140) of a vehicle; and the second switch (32) is connected between an assembled battery (10) with several cells and the rotating electric machine (130).

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