JP2020017355A - Battery pack - Google Patents

Abstract

To provide a battery pack with suppressed degradation in radiation performance.SOLUTION: A battery pack comprises: a battery module having a plurality of battery cells 13 and 15 housed in a sensor housing 60; a body part 89 provided with fixing walls 91, 92a, and 92b to which the battery module is fixed, and a facing wall 92c which erects from the fixing walls while being separated from and opposed to the battery module; a coupling wall 90 which is coupled to the body part via the battery module in a manner approaching the facing wall; and a heat transfer sheet 98 sandwiched between the battery module and the coupling wall.SELECTED DRAWING: Figure 13

Description

  The disclosure described herein relates to a battery pack.

  Patent Literature 1 discloses an assembled battery configured by combining a prismatic battery and a separator. The heat conductive sheet is in contact with the cooling surface exposed from the separator of the prismatic battery. The heat conductive sheet is pressed against the cooling surface by the cooling plate.

JP 2011-34775 A

  In the cooling structure of an assembled battery disclosed in Patent Document 1, one of the six surfaces of the prismatic battery is a cooling surface. Therefore, there is a problem that the heat dissipation performance of the prismatic battery is low.

  Therefore, an object of the disclosure described in this specification is to provide a battery pack in which a decrease in heat radiation performance is suppressed.

One of the disclosures is a battery module (1) in which a plurality of battery cells (11 to 15) are housed in a sensor housing (60);
A main body (89) including a fixed wall (91, 92a, 92b) to which the battery module is fixed, and an opposing wall (92c) rising from the fixed wall and facing the battery module at a distance from the fixed wall;
A connecting wall (90) connected to the main body in a manner approaching the opposing wall via the battery module;
A heat transfer sheet (98) sandwiched between the battery module and the connection wall.

  As described above, in the present disclosure, the battery module (1) is fixed to the fixing walls (91, 92a, 92b) of the main body (89). Then, the heat transfer sheet (98) is sandwiched between the battery module (1) and the connection wall (90). According to this, the heat generated in the battery module (1) can be conducted to the fixed walls (91, 92a, 92b) and the connecting wall (90). A decrease in the heat radiation performance of the battery module (1) is suppressed.

  In the present disclosure, the opposing wall (92c) and the battery module (1) are separated from each other. The battery module (1) is fixed to fixed walls (91, 92a, 92b). The connection wall (90) is connected to the main body (89) so as to approach the opposing wall (92c) via the battery module (1).

  Therefore, in the present disclosure, for example, unlike the configuration in which the battery module is sandwiched between the opposing wall and the connection wall, a space is formed between the opposing wall (92c) and the battery module (1). Thereby, for example, a member for connecting the battery module (1) and the external device can be arranged in this space. In this way, the limitation on the arrangement of members in the main body (89) is relaxed.

  It should be noted that the reference numbers in parentheses described above merely indicate the correspondence with the configurations described in the embodiments described below, and do not limit the technical scope at all.

FIG. 2 is a circuit diagram illustrating a power supply system. FIG. 3 is an exploded perspective view for explaining a battery pack. It is a perspective view for explaining a battery pack. It is a perspective view for explaining a battery module. FIG. 3 is an exploded perspective view for explaining a battery module. 4 is a diagram for explaining a battery case. 4 is a diagram for explaining a battery case. 5 is a diagram for explaining a wiring case. 5 is a diagram for explaining a wiring case. It is a perspective view for explaining arrangement of a battery module and a circuit board. It is a top view which shows a housing | casing typically. It is a chart which shows a housing typically. FIG. 5 is a top view for schematically explaining the connection between the main body and the connection wall. It is a side view for explaining typically connection of a main part and a connection wall. 5 is a diagram schematically illustrating a housing on which a battery module is mounted. It is a top view which shows a battery pack typically. It is a side view which shows a battery pack typically. It is a side view for explaining the modification of a heat transfer sheet cell. It is a side view for explaining the modification of a connection wall. It is a side view for explaining the modification of a connection wall. It is a side view for explaining the modification of a connection wall. It is a rear view for explaining a radiation fin. It is a figure for explaining the modification of a connecting wall. It is a top view which shows the modification of a battery pack typically. It is a top view which shows the modification of a battery pack typically. It is a top view which shows the modification of a battery pack typically.

  Hereinafter, embodiments will be described with reference to the drawings.

(1st Embodiment)
A battery pack 100 according to the present embodiment and a power supply system 200 including the same will be described with reference to FIGS.

<Overview of power supply system>
The power supply system 200 is mounted on a vehicle. The power supply system 200 includes a plurality of in-vehicle devices mounted on a vehicle and the battery pack 100. A lead storage battery 110 is one of the in-vehicle devices. The battery pack 100 has an assembled battery 10. The power supply system 200 configures a two-power supply system with the lead storage battery 110 and the assembled battery 10.

  An engine 140 is another on-vehicle device. The vehicle equipped with the power supply system 200 has an idle stop function that stops the engine 140 when a predetermined stop condition is satisfied and restarts the engine 140 when a predetermined start condition is satisfied.

  As shown in FIG. 1, the power supply system 200 includes a starter motor 120, a rotating electric machine 130, an electric load 150, a host ECU 160, and an MGECU 170 in addition to the lead storage battery 110 and the engine 140 described above. Each of the lead storage battery 110, the starter motor 120, and the electric load 150 is electrically connected to the battery pack 100 via the first wire harness 210. The rotating electric machine 130 is electrically connected to the battery pack 100 via the second wire harness 220. The lead storage battery 110, the starter motor 120, the rotating electric machine 130, the engine 140, and the electric load 150 correspond to external devices.

  The host ECU 160 and the MGECU 170 are electrically connected to the lead storage battery 110 and the battery pack 100 via wiring (not shown). Similarly, various other ECUs mounted on the vehicle are also electrically connected to the lead storage battery 110 and the battery pack 100 via wiring (not shown).

  As described above, the power supply system 200 constructs a two-power supply system using two power sources, the lead storage battery 110 and the battery pack 100 (assembled battery 10).

<Components of power supply system>
The lead storage battery 110 generates an electromotive voltage by a chemical reaction. The lead storage battery 110 has a higher storage capacity than the battery pack 10.

  Starter motor 120 starts engine 140. Starter motor 120 is mechanically connected to engine 140 when engine 140 is started. The rotation of the starter motor 120 causes the crankshaft of the engine 140 to rotate. When the rotation speed of the crankshaft of engine 140 exceeds a predetermined rotation speed, atomized fuel is injected from the fuel injection valve into the combustion chamber. At this time, a spark is generated by the spark plug. As a result, the fuel explodes, and the engine 140 starts to rotate autonomously. The propulsion of the vehicle is obtained by the power of the engine 140. When the engine 140 starts to autonomously rotate, the mechanical connection between the starter motor 120 and the engine 140 is released.

  The rotating electric machine 130 performs power running and power generation. A power converter (not shown) is connected to the rotating electric machine 130. This power converter is electrically connected to the second wire harness 220.

  The power converter converts a DC voltage supplied from at least one of the lead storage battery 110 and the battery pack 10 of the battery pack 100 to an AC voltage. This AC voltage is supplied to rotating electric machine 130. Thus, the rotating electric machine 130 runs power.

  The rotating electric machine 130 is connected to the engine 140. The rotating electric machine 130 and the engine 140 can mutually transmit rotational energy via a belt or the like. Rotational energy generated by the power running of the rotating electric machine 130 is transmitted to the engine 140. Thereby, rotation of engine 140 is promoted. As a result, vehicle running 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 assists in running the vehicle, but also has a function of rotating a crankshaft when the engine 140 is restarted.

  The rotary electric machine 130 also has a function of generating power by at least one of the rotational energy of the engine 140 and the rotational energy of the wheels of the vehicle. The rotating electric machine 130 generates an AC voltage by power generation. This AC voltage is converted into a DC voltage by the power converter. This DC voltage is supplied to each of the battery pack 100, the lead storage battery 110, and the electric load 150.

  Engine 140 generates propulsion of the vehicle by burning and driving fuel. As described above, when the engine 140 is started, the crankshaft is rotated by the starter motor 120. However, when the engine 140 is once stopped by the idle stop and then restarted, the rotating electric machine 130 rotates the crankshaft when the above-described predetermined starting condition is satisfied.

  The electric load 150 has a general load 151 and a protection load 152. The general load 151 includes in-vehicle devices, such as a seat heater, a blower fan, an electric compressor, a room light, and a headlight, for which supply power may not be constant. The protection load 152 includes an electric shift position, an electric power steering (EPS), a brake (ABS), a door lock, a navigation system, and on-vehicle equipment that requires a constant power supply such as audio. The protection load 152 exemplified here has a property of switching from the on state to the off state when the supply voltage falls below the reset threshold. The protection load 152 includes in-vehicle devices that are more relevant to vehicle running than the general load 151.

  The configuration in which the above-described various in-vehicle devices are included in the general load 151 and the protection load 152 is merely an example. Various in-vehicle devices can be appropriately allocated to the general load 151 and the protection load 152 according to a change in the in-vehicle system. For example, a configuration in which the general load 151 includes EPS or ABS can be adopted.

  The host ECU 160 and the MGECU 170 are one of various ECUs mounted on the vehicle. These various ECUs are electrically connected to each other via a bus wiring 161 to form a vehicle-mounted network. The various ECUs perform the cooperative control to control the combustion of the engine 140 and the powering and power generation of the rotating electric machine 130. The host ECU 160 controls the battery pack 100, and the MGECU 170 controls the rotating electric machine 130.

  Although not shown, the power supply system 200 includes, in addition to the above-described on-vehicle devices, sensors for measuring physical quantities such as various voltages and currents and vehicle information such as an accelerator pedal depression amount and a throttle valve opening. Have. Detection signals detected by these various sensors are input to various ECUs.

  ECU is an abbreviation of electronic control unit. The ECU has at least one arithmetic processing unit (CPU) and at least one memory device (MMR) as a storage medium for storing programs and data. The ECU is provided by a microcomputer having a computer-readable storage medium. The storage medium is a non-transitional substantial storage medium that temporarily stores a computer-readable program. The storage medium can be provided by a semiconductor memory or a magnetic disk or the like.

<Overview of Battery Pack>
As shown in FIG. 1, the battery pack 100 includes a battery pack 10, a circuit board 20, a switch 30, a sensor unit 40, and a power supply bus bar 50. As shown in FIGS. 2 to 4, the battery pack 100 has a module case 60, a connection bus bar 70, and a pack case 80. 2 and 3, illustration of the circuit board 20 and the power supply bus bar 50 is omitted.

  The battery pack 10 is smaller in size and lighter in weight than the lead storage battery 110. The battery pack 10 has a higher energy density than the lead storage battery 110.

  The circuit board 20 has a wiring board 21 and a BMU 22. A part of the switch 30 and the BMU 22 are mounted on the wiring board 21. The rest of the switch 30 and the battery pack 10 are electrically connected to the circuit board 20 via the power supply bus bar 50. Thus, an electric circuit of the battery pack 100 is configured. The sensor unit 40 is electrically connected to the electric circuit.

  The electric circuit of the battery pack 100 is electrically connected to an external connection terminal indicated by a double circle in FIG. The external connection terminals include a first external connection terminal 100a, a second external connection terminal 100b, a third external connection terminal 100c, a fourth external connection terminal 100d, and a fifth external connection terminal 100e.

  The first external connection terminal 100a, the fourth external connection terminal 100d, and the fifth external connection terminal 100e are electrically connected to the lead storage battery 110, the starter motor 120, and the electric load 150 via the first wire harness 210, respectively. Have been. The second external connection terminal 100b is electrically connected to the rotating electric machine 130 via the second wire harness 220. The third external connection terminal 100c is bolted to a vehicle body. The bolt inserted into the third external connection terminal 100c functions to connect the battery pack 100 to the vehicle body. As a result, the battery pack 100 is grounded to the body.

  As shown in FIG. 1, the first wire harness 210 is divided into one that connects the lead storage battery 110, the starter motor 120, and the general load 151, and one that connects the protection load 152. The end of the first wire harness 210 that connects the lead storage battery 110, the starter motor 120, and the general load 151 is bifurcated. One of the forked ends is connected to the first external connection terminal 100a, and the other is connected to the fifth external connection terminal 100e. An end of the first wire harness 210 for connecting the protection load 152 is connected to the fourth external connection terminal 100d.

  As shown in FIGS. 4 and 5, the module case 60 has a battery case 61 and a wiring case 62. The battery pack 10 is housed in the battery case 61. The wiring case 62 is connected to the battery case 61. Thereby, the assembled battery 10 is stored in the battery case 61 and the wiring case 62. The electrode terminals of a plurality of battery cells constituting the assembled battery 10 are electrically connected in series via the connection bus bar 70 shown in FIGS. The module case 60 corresponds to a sensor housing.

  As shown in FIG. 2, the module case 60 has an insulating case 69 in addition to the battery case 61 and the wiring case 62. The insulating case 69 is connected to the wiring case 62 so as to cover the connecting bus bar 70. Thus, the battery module 1 is configured. 4 and 5, the illustration of the insulating case 69 is omitted to explain the wiring case 62 and the power supply bus bar 50.

  As shown in FIGS. 2 and 3, the pack case 80 has a housing 87. The pack case 80 has a cover (not shown). The housing 87 and the cover form a storage space. The battery pack 10, the circuit board 20, the switch 30, the sensor unit 40, the power supply bus bar 50, the module case 60, and the connection bus bar 70 are stored in the storage space. In addition, a suppression plate (not shown) is stored in the storage space.

  The suppression plate is bolted to the housing 87. In a state where the suppression plate is fixed to the case 87, the battery module 1 is located between the suppression plate and the case 87. The displacement and expansion of the battery module 1 in the height direction are suppressed by the suppression plate and the housing 87.

<Components of battery pack>
The assembled battery 10 has a plurality of battery cells. This battery cell is specifically a lithium ion secondary battery. Lithium ion secondary batteries generate an electromotive voltage by a chemical reaction. A current flows through the battery cell due to the generation of the electromotive voltage. As a result, the battery cells generate heat and generate gas. Therefore, the battery cell expands. The battery cell is not limited to the above example. For example, as the battery cell, a secondary battery such as a nickel hydride secondary battery or an organic radical battery can be employed.

  As described above, the circuit board 20 includes the wiring board 21 and the BMU 22. The wiring board 21 is a printed board in which a wiring pattern made of a conductive material is formed on an insulating substrate. A first power supply line 23, a second power supply line 24, and a third power supply line 25 are formed as wiring patterns on at least one of the surface and the inside of the insulating substrate. As shown in FIG. 10, the wiring board 21 (circuit board 20) is arranged to face the module case 60.

  A conductive plate (not shown) is fixed to the wiring board 21. Bolt holes are formed in the conductive plate. A bolt is passed through the bolt hole of the conductive plate. This bolt is fixed to the housing 87. Thus, the wiring board 21 is mechanically and electrically connected to the housing 87.

  As will be described later, the casing 87 is connected to the ground potential. Therefore, the conductive plate of the wiring board 21 is connected to the ground potential. The BMU 22 mounted on the wiring board 21 uses the potential of the conductive plate as a reference potential.

  Terminals that are electrically connected to the wiring pattern are formed on the wiring board 21. The terminals include a first internal terminal 26a, a second internal terminal 26b, a third internal terminal 26c, and a fourth internal terminal 26d. The wiring board 21 is provided with the fifth external connection terminals 100e. The fifth external connection terminal 100e is a connector. The fifth external connection terminal 100e is also electrically connected to the wiring pattern. The electrical connection between these wiring patterns and the internal terminals and the fifth external connection terminals 100e will be described later in the description of the circuit configuration of the battery pack 100.

  The switch 30 includes 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 housing 87. Each of the third switch 33 and the fourth switch 34 and the fifth switch 35 and the sixth switch 36 are mounted on the wiring board 21.

  Each of the first switch 31 to the fourth switch 34 has a semiconductor switch. This semiconductor switch is specifically an N-channel MOSFET. Therefore, each of the first switch 31 to the fourth switch 34 is closed by the input of the high-level control signal. Each of the first switch 31 to the fourth switch 34 is opened when a low-level control signal is input.

  An IGBT or the like can be used as a semiconductor switch of the first switch 31 to the fourth switch 34. In this case, a diode is connected to the IGBT in parallel.

  Each of the fifth switch 35 and the sixth switch 36 is a mechanical relay. More specifically, each of the fifth switch 35 and the sixth switch 36 is a normally closed electromagnetic relay. Therefore, each of the fifth switch 35 and the sixth switch 36 is opened by the input of the high-level control signal. Each of the fifth switch 35 and the sixth switch 36 is closed by inputting a low-level control signal. In other words, each of the fifth switch 35 and the sixth switch 36 is closed when the input of the high-level control signal is interrupted.

  Each of the first switch 31 to the fourth switch 34 has at least one opening / closing unit in which two MOSFETs are connected in series. These two MOSFETs have their source electrodes connected to each other. The gate electrodes of the two MOSFETs are electrically independent. The MOSFET has a parasitic diode. The anodes of the parasitic diodes of the two MOSFETs are connected to each other. The gate electrode is electrically connected to the circuit board 20.

  The first switch 31 and the second switch 32 have a plurality of open / close units. The plurality of opening / closing sections are connected in parallel. The source electrodes of the plurality of opening / closing portions are electrically connected to each other.

  The third switch 33 has one opening / closing unit. The fourth switch 34 has a plurality of open / close units. The plurality of open / close sections of the fourth switch 34 are connected in series.

  FIG. 1 shows two open / close sections of the first switch 31 and the second switch 32 which are connected in parallel. Two open / close sections of the fourth switch 34 connected in series are shown. The number of these opening / closing portions can be appropriately determined according to the amount of current, redundancy, and the like.

  A larger amount of current flows through the first switch 31 and the second switch 32 than the third switch 33 to the sixth switch 36 on a time average basis. Therefore, as described above, the first switch 31 and the second switch 32 have a configuration in which a plurality of open / close units are connected in parallel.

  As described above, the sensor unit 40 is electrically connected to the electric circuit. The sensor unit 40 has a sensor element that detects the state of each of the battery pack 10 and the switch 30. The sensor unit 40 has a temperature sensor, a current sensor, and a voltage sensor as sensor elements.

  The sensor unit 40 detects the temperature, the current, and the voltage of the battery pack 10. The sensor unit 40 outputs it to the BMU 22 as a state signal of the battery pack 10. The sensor unit 40 detects the temperature, the current, and the voltage of the switch 30. The sensor unit 40 outputs this to the BMU 22 as a state signal of the switch 30.

  FIG. 1 clearly shows a voltage sensor 41 for detecting the voltage of the battery pack 10 and a temperature sensor 42 for detecting the temperature of the battery pack 10 as representatives of the plurality of sensors.

  The sensor section 40 has a submergence sensor 43 in addition to the various sensors described above. The resistance value of the submersion sensor 43 changes due to water or the like. The submersion sensor 43 causes the BMU 22 to detect this change in the resistance value. The BMU 22 detects submergence of the battery pack 100 based on whether or not the change in resistance continues for a predetermined time.

  The BMU 22 controls the switch 30 based on at least one of a state signal of the sensor unit 40 and a command signal from the host ECU 160. BMU is an abbreviation for battery management unit.

  As described above, each of the first switch 31 to the fourth switch 34 has a plurality of semiconductor switches. For example, when controlling the opening and closing of the first switch 31, the BMU 22 controls all the semiconductor switches of the first switch 31 to be simultaneously closed or open. That is, the BMU 22 simultaneously outputs a high-level control signal or a low-level control signal to the gate electrodes of all the semiconductor switches included in the first switch 31.

  The BMU 22 may adjust the closing time of the semiconductor switch by intermittently outputting a high-level control signal during the period in which the semiconductor switch is closed. Briefly, the BMU 22 may control the pulse width of the semiconductor switch.

  The BMU 22 determines the state of charge (SOC) of the battery pack 10 and the abnormality of the switch 30 based on the state signal of the sensor unit 40. SOC is an abbreviation for state of charge. The BMU 22 outputs a signal (determination information) for determining the SOC and the abnormality to the host ECU 160.

  The host ECU 160 determines the control of the switch 30 based on the determination information input from the BMU 22 and the vehicle information input from other various ECUs. Then, host ECU 160 outputs a command signal including the determined control of switch 30 to BMU 22.

  The BMU 22 controls the switch 30 based on a command signal from the host ECU 160. When the BMU 22 determines that the battery pack 100 has been submerged by the status signal of the submergence sensor, the BMU 22 arbitrarily stops outputting the control signal to the switch 30. Thus, the electrical connection of the battery pack 10 is cut off.

  When the temperature of the switch 30 becomes high, the BMU 22 limits the drive of the switch 30. For example, when the BMU 22 controls the pulse width of the semiconductor switch of the switch 30, the BMU 22 lowers its on-duty ratio. This shortens the energization time of the semiconductor switch. As a result, heat generation of the semiconductor switch is suppressed.

  The power supply bus bar 50 is made of a conductive material such as aluminum or copper. The power supply bus bar 50 can be manufactured, for example, by the methods listed below. The power supply bus bar 50 can be manufactured by bending a single flat plate. The power supply bus bar 50 can be manufactured by integrally connecting a plurality of flat plates. The power supply bus bar 50 can be manufactured by welding a plurality of flat plates. The power supply bus bar 50 can be manufactured by pouring a molten conductive material into a mold. The power supply bus bar 50 can be manufactured by a manufacturing method different from the manufacturing methods listed above. The method for manufacturing the power supply bus bar 50 is not particularly limited. Furthermore, for example, an insulated wire may be used as the power supply bus bar 50.

  The battery pack 100 has a first power supply bus bar 51, a second power supply bus bar 52, a third power supply bus bar 53, and a fourth power supply bus bar 54 as the power supply bus bar 50. The circuit board 20 and the battery pack 10 and the circuit board 20 and the external connection terminals are electrically connected by the plurality of power supply bus bars. In FIG. 1, each of the power supply bus bars is shown thicker than the power supply lines of the wiring board 21. These power supply bus bars are provided on an insulating resin stand 88 schematically shown in FIG. The resin stand 88 is disposed to face the wiring case 62 in a vertical direction described later.

  As described above, the module case 60 includes the battery case 61, the wiring case 62, and the insulating case 69. Each of these three cases is made of an insulating resin material. The specific heat of each of the three cases is higher than that of air.

  The connection bus bar 70 is formed by the same manufacturing method as that of the power supply bus bar 50. The connection bus bar 70 is provided on the wiring case 62. The connection bus bar 70 electrically and mechanically connects a plurality of battery cells of the battery pack 10.

  As described above, the pack case 80 has the housing 87 and the cover. The housing 87 has a main body 89 and a connecting wall 90. The main body 89 and the connecting wall 90 can be manufactured by aluminum die casting. The main body 89 and the connecting wall 90 can also be manufactured by pressing iron or stainless steel. The cover is made of resin or metal.

  The main body 89 has a bottom wall 91 and a side wall 92 rising from an inner bottom surface 91 a of the bottom wall 91. The connecting wall 90 is connected to the bottom wall 91 and the side wall 92. The side wall 92 and the connecting wall 90 form an opening above the bottom wall 91. This opening is covered by the cover. This forms a storage space.

  The pack case 80 (battery pack 100) of the present embodiment is provided below a seat of a vehicle. However, the arrangement of the battery pack 100 is not limited to this. Battery pack 100 can also be arranged in, for example, a space between a rear seat and a trunk room, a space between a driver's seat and a passenger seat, and the like. The housing 87 will be described later in detail.

<Circuit configuration of battery pack>
Next, the circuit configuration of the battery pack 100 will be described. The connection between each power supply bus bar and each switch described below is performed by TIG welding. The connection between each power supply bus bar and the external connection terminal is performed by bolting. The connection between each power supply bus bar and the circuit board 20 is performed by brazing. Each power supply bus bar and each switch may be connected by laser welding.

  As shown in FIG. 1, the first external connection terminal 100a and one end of the first switch 31 are electrically connected via a first power supply bus bar 51. A part is branched from the first power supply bus bar 51. The branch portion 51a of the first power supply bus bar 51 is electrically connected to the first internal terminal 26a of the wiring board 21.

  The other end of the first switch 31 and the second external connection terminal 100b are electrically connected via the second power supply bus bar 52. A part is branched from the second power supply bus bar 52. The branch portion 52a of the second power supply bus bar 52 is electrically connected to one end of the second switch 32.

  In addition, a part of the second power supply bus bar 52 is branched from a portion between the other end of the first switch 31 and a connection portion with the branch portion 52a. The branch portion 52b is electrically connected to the fourth internal terminal 26d of the wiring board 21.

  The other end of the second switch 32 and the positive electrode of the battery pack 10 are electrically connected via a third power supply bus bar 53. A part is branched from the third power supply bus bar 53. The branch portion 53a of the third power supply bus bar 53 is electrically connected to the second internal terminal 26b of the wiring board 21. The negative electrode of the battery pack 10 is electrically connected to the third external connection terminal 100c.

  The first internal terminal 26 a and the second internal terminal 26 b of the wiring board 21 are electrically connected via the first power supply line 23. A third switch 33 and a fourth switch 34 are connected in series to the first power supply line 23 in order from the first internal terminal 26a to the second internal terminal 26b.

  The third internal terminal 26 c and the fourth internal terminal 26 d of the wiring board 21 are electrically connected via the second power supply line 24. The third internal terminal 26c is electrically connected to the fourth external connection terminal 100d via the fourth power supply bus bar 54.

  A sixth switch 36 is provided on the second power supply line 24. The midpoint between the third internal terminal 26c and the sixth switch 36 in the second power supply line 24 is connected to the midpoint between the third switch 33 and the fourth switch 34 in the first power supply line 23. I have. Thus, the sixth switch 36 is connected in parallel with the third switch 33.

  A midpoint between the fourth internal terminal 26 d and the sixth switch 36 in the second power supply line 24 is electrically connected to the fifth external connection terminal 100 e via the third power supply line 25. A fifth switch 35 is provided on the third power supply line 25. Thus, the fifth switch 35 is connected in parallel with the first switch 31.

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

  The midpoint of the first switch 31 and the second switch 32 is connected to the midpoint of the fourth switch 34 and the third switch 33 via the sixth switch 36. The midpoint between the first switch 31 and the second switch 32 is connected to the fifth external connection terminal 100e via the fifth switch 35.

  With the above electrical connection configuration, by controlling the opening and closing of the first switch 31, the electrical connection between the first external connection terminal 100a and the second external connection terminal 100b is controlled. In other words, the electrical connection between the lead storage battery 110 and the rotating electric machine 130 is controlled by controlling the opening and closing of the first switch 31.

  By controlling the opening and closing of the second switch 32, the electrical connection between the second external connection terminal 100b and the battery pack 10 is controlled. In other words, by controlling the opening and closing of the second switch 32, the electrical connection between the rotating electric machine 130 and the battery pack 10 is controlled.

  By controlling the opening and closing of the fourth switch 34, the electrical connection between the second internal terminal 26b and the third internal terminal 26c is controlled. In other words, the electrical connection between the battery pack 10 and the protection load 152 is controlled by controlling the opening and closing of the fourth switch 34.

  By controlling the opening and closing of the third switch 33, the electrical connection between the first internal terminal 26a and the third internal terminal 26c is controlled. In other words, the electrical connection between the lead storage battery 110 and the protective load 152 is controlled by controlling the opening and closing of the third switch 33.

  Further, by controlling the opening and closing of the sixth switch 36, the electrical connection between the fourth internal terminal 26d and the third internal terminal 26c is controlled. In other words, the electrical connection between the rotating electric machine 130 and the protective load 152 is controlled by controlling the opening and closing of the sixth switch 36.

  By controlling the opening and closing of the fifth switch 35, the electrical connection between the fourth internal terminal 26d and the fifth external connection terminal 100e is controlled. In other words, the electrical connection between the rotating electrical machine 130 and the lead storage battery 110 is controlled by controlling the opening and closing of the fifth switch 35.

  Furthermore, by simultaneously opening and closing the fifth switch 35 and the sixth switch 36, the electrical connection between the third internal terminal 26c and the fifth external connection terminal 100e is controlled. In other words, the electrical connection between the protective load 152 and the lead storage battery 110 is controlled by simultaneously opening and closing the fifth switch 35 and the sixth switch 36.

<Structure of battery pack>
Hereinafter, three directions that are orthogonal to each other are referred to as a horizontal direction, a vertical direction, and a height direction. The lateral direction is along the left-right direction of the vehicle. The height direction is along the vertical direction of the vehicle. When the vehicle is stopped on a horizontal plane, the height direction is along the vertical direction. The horizontal and vertical directions are along the horizontal direction.

<Battery pack>
As described above, the battery pack 10 has a plurality of battery cells. This battery cell has a rectangular parallelepiped shape. For this purpose, the battery cell has six surfaces. As shown in FIG. 5, the battery cell has a first main surface 10a and a second main surface 10b facing in the height direction. The battery cell has a first side face 10c and a second side face 10d facing in the lateral direction. The battery cell has an upper end face 10e facing in the vertical direction. Further, as shown in FIG. 13, the battery cell has a lower end face 10f facing in the vertical direction. Of these six surfaces, the first main surface 10a and the second main surface 10b have larger areas than the other four surfaces. The battery cell has a flat shape with a small length (thickness) between the first main surface 10a and the second main surface 10b.

  A positive electrode terminal 10g and a negative electrode terminal 10h as electrode terminals are formed on the upper end surface 10e of the battery cell. The positive terminal 10g and the negative terminal 10h have a rectangular parallelepiped shape. The positive electrode terminal 10g and the negative electrode terminal 10h protrude vertically from the upper end face 10e so as to be separated from the battery cell.

  The positive electrode terminal 10g and the negative electrode terminal 10h are arranged side by side in the lateral direction. The positive electrode terminal 10g is located on the first side surface 10c side. The negative electrode terminal 10h is located on the second side surface 10d side.

  As shown in FIG. 5, between the positive electrode terminal 10g and the negative electrode terminal 10h on the upper end face 10e, a safety valve 10i having low rigidity is locally formed. As described above, the battery cells expand due to the generation of gas. When the internal pressure of the battery cell increases due to the generation of gas, a crack occurs in the safety valve 10i. Thereby, the gas of the battery cell is discharged outside through the safety valve 10i.

  A packing 10j is provided in a region where the positive electrode terminal 10g, the negative electrode terminal 10h, and the safety valve 10i are not formed on the upper end surface 10e. The packing 10j is made of an elastic material such as rubber. The packing 10j has an annular shape that opens in the vertical direction. The length of the packing 10j in the vertical direction is longer than each of the positive electrode terminal 10g and the negative electrode terminal 10h. The packing 10j is sandwiched between the battery cell and the wiring case 62 by connecting the battery case 61 and the wiring case 62.

  The battery pack 10 of the present embodiment includes a first battery cell 11, a second battery cell 12, a third battery cell 13, a fourth battery cell 14, and a fifth battery cell 15. A battery stack is formed by arranging the plurality of battery cells. These plurality of battery cells are electrically connected in series. The first battery cell 11 becomes the battery cell with the lowest potential. The fifth battery cell 15 becomes the battery cell with the highest potential.

  In the present embodiment, a first battery stack 10l and a second battery stack 10m are configured as the above-described battery stack. A first battery cell 11, a fourth battery cell 14, and a fifth battery cell 15 of the five battery cells are distributed to the first battery stack 10l. The remaining second battery cells 12 and third battery cells 13 are distributed to the second battery stack 10m.

  In the first battery stack 101, the first battery cell 11, the fourth battery cell 14, and the fifth battery cell 15 are arranged in order in the height direction. In the second battery stack 10m, the second battery cells 12 and the third battery cells 13 are arranged in the height direction. These battery stacks are stored in the battery case 61.

<Battery case>
Next, the battery case 61 will be described with reference to FIGS. Column (a) of FIG. 6 shows a perspective view of the battery case. Column (b) of FIG. 6 shows a front view of the battery case. Column (a) of FIG. 7 shows a rear view of the battery case. Column (b) of FIG. 7 shows a top view of the battery case.

  As shown in FIGS. 6 and 7, the battery case 61 has a box shape that opens in the vertical direction. The battery case 61 has a bottom wall 63 facing the vertical direction, and a peripheral wall 64 that stands vertically in an annular shape from the inner surface 61 a of the bottom wall 63. An opening window 63a is formed in the bottom wall 63 so as to vertically penetrate the inner surface 61a and the outer surface 61b on the back side.

  The peripheral wall 64 has an upper wall 64a and a lower wall 64b arranged in the height direction, and a left wall 64c and a right wall 64d arranged in the lateral direction. In the circumferential direction around the vertical direction, the upper wall 64a, the right wall 64d, the lower wall 64b, and the left wall 64c are sequentially connected to form an annular shape.

  The battery case 61 has a first partition wall 64e that divides a region surrounded by the annular peripheral wall 64 into two in the horizontal direction. The area surrounded by the peripheral wall 64 of the battery case 61 by the first partition wall 64e includes a first stack storage space 64f for storing the first battery stack 101 and a second stack storage space for storing the second battery stack 10m. 64 g.

  Further, the battery case 61 has a second partition wall 64h for dividing the stack storage space into individual storage spaces corresponding to the respective battery cells. The first stack storage space 64f is provided with two second partition walls 64h. These two second partition walls 64h are arranged side by side in the height direction in the first stack storage space 64f. These two second partition walls 64h connect the first partition wall 64e and the right wall 64d. Thereby, the first stack storage space 64f is partitioned into a first storage space 64i, a fourth storage space 64l, and a fifth storage space 64m that are arranged in order from the lower wall 64b to the upper wall 64a in the height direction. .

  One second partition wall 64h is provided in the second stack storage space 64g. The one second partition wall 64h is located between the upper wall 64a and the lower wall 64b in the second stack storage space 64g. The one second partition wall 64h connects the left wall 64c and the first partition wall 64e. As a result, the second stack storage space 64g is partitioned into a second storage space 64j and a third storage space 64k arranged in order from the lower wall 64b to the upper wall 64a in the height direction.

  As described above, the first stack storage space 64f has three storage spaces. On the other hand, the second stack storage space 64g has two storage spaces. Therefore, the first stack storage space 64f is longer in the height direction than the second stack storage space 64g.

  As shown in FIG. 6B, the lower wall 64b that defines a part of each of the two stack storage spaces has a shape extending in the lateral direction. Therefore, the position of the lower wall 64b in the height direction of the part that divides the first stack storage space 64f is equal to the position of the part that divides the second stack storage space 64g in the height direction.

  On the other hand, the part of the upper wall 64a that partitions a part of the first stack storage space 64f is more distant from the lower wall 64b in the height direction than the part that partitions the part of the second stack storage space 64g. ing. A portion of the upper wall 64a between a portion that partitions a part of the first stack storage space 64f and a portion that partitions a part of the second stack storage space 64g extends along the height direction. Thus, the upper wall 64a has a crank shape in a plane defined by the height direction and the lateral direction.

  Due to the shapes of the lower wall 64b and the upper wall 64a described above, the first storage space 64i and the second storage space 64j are arranged side by side. The fourth storage space 64l and the third storage space 64k are arranged in the horizontal direction. An empty space for one storage space is formed on the side of the third storage space 64k in the lateral direction of the fifth storage space 64m.

  As shown in FIG. 10, a part of the circuit board 20 is provided in this empty space. The wiring board 21 of the circuit board 20 has a flat plate shape with a small thickness in the height direction. The side portion along the vertical direction of the wiring board 21 is arranged side by side with the fifth storage space 64m.

  The above-mentioned five individual storage spaces are each opened in the vertical direction. Battery cells are inserted from the openings of these storage spaces into the storage spaces. Each battery cell is inserted into the corresponding storage space until the lower end face 10 f of the battery cell contacts the inner surface 61 a of the bottom wall 63 of the battery case 61. In this inserted state, the positive terminal 10g and the negative terminal 10h of each battery cell protrude out of the storage space. In addition, the upper end surface 10e of each of the first main surface 10a, the second main surface 10b, the first side surface 10c, and the second side surface 10d of the battery cell also protrudes outside the battery case 61.

  In the first stack storage space 64f, the second main surfaces 10b of each of the first battery cell 11 and the fourth battery cell 14 face each other in the height direction. The first main surfaces 10a of the fourth battery cell 14 and the fifth battery cell 15 are opposed to each other in the height direction. Thereby, the positive electrode terminals 10g and the negative electrode terminals 10h are alternately arranged in the height direction.

  In the second stack storage space 64g, the second main surfaces 10b of the second battery cells 12 and the third battery cells 13 face each other in the height direction. Thereby, the positive electrode terminals 10g and the negative electrode terminals 10h are alternately arranged in the height direction.

  The positive terminal 10g of the first battery cell 11 and the negative terminal 10h of the second battery cell 12 are arranged in the horizontal direction. The negative terminal 10h of the fourth battery cell 14 and the positive terminal 10g of the third battery cell 13 are arranged side by side.

  In addition to the bottom wall 63 and the peripheral wall 64 described above, the battery case 61 extends in a direction away from the center of the battery case 61 along a plane defined by the lateral direction and the height direction from the tip of the peripheral wall 64. It has a flange portion 65. The first flange portion 65 is formed on each of the upper wall 64a, the right wall 64d, the lower wall 64b, and the left wall 64c of the peripheral wall 64 to form an annular shape.

  A plurality of first screw holes 61c extending in the vertical direction are formed in portions of the first flange portion 65 formed on the right wall 64d and the left wall 64c, respectively. A first screw hole 61c is also formed in the first partition wall 64e. A first screw hole 61c is also formed in a portion of the first flange portion 65 formed on the upper wall 64a. The first screw holes 61c formed in the first flange portion 65 are arranged in the height direction with the first screw holes 61c formed in the first partition wall 64e. Each of the plurality of first screw holes 61c is opened in the inner surface 61a of the battery case 61.

<Wiring case>
Next, the wiring case 62 will be described with reference to FIGS. FIG. 8A shows a perspective view of the wiring case. FIG. 8B shows a front view of the wiring case. Column (a) of FIG. 9 shows a rear view of the wiring case. The section (b) of FIG. 9 shows a top view of the wiring case.

  As shown in FIGS. 8 and 9, the wiring case 62 has a shape extending in the lateral direction. The portion of the wiring case 62 facing the battery cell is recessed in a direction away from the battery case 61 in the vertical direction. Thus, the wiring case 62 has a box shape that opens in the vertical direction.

  Specifically, the wiring case 62 has a lid wall 66 facing in the vertical direction, and an annular wall 67 erected from the lid wall 66 in an annular shape. The lid wall 66 is arranged to face the battery cell in the vertical direction. The annular wall 67 stands on the battery cell side from the edge of the surface (inner surface 62a) of the cover wall 66 on the battery case 61 side.

  The annular wall 67 has an upper wall 67a and a lower wall 67b arranged in the height direction, and a left wall 67c and a right wall 67d arranged in the lateral direction. In the circumferential direction around the vertical direction, the upper wall 67a, the right wall 67d, the lower wall 67b, and the left wall 67c are sequentially connected to form an annular shape. In a plane defined by the lateral direction and the height direction, the annular wall 67 has a similar shape to the peripheral wall 64 of the battery case 61.

  For this reason, the upper wall 67a of the annular wall 67 is similar to the upper wall 64a of the peripheral wall 64 in that the portion on the first stack storage space 64f side is lower than the portion on the second stack storage space 64g side in the height direction. 64b. A portion of the upper wall 67a between the first stack storage space 64f and the second stack storage space 64g extends along the height direction. Thus, the upper wall 67a has a crank shape in a plane defined by the height direction and the lateral direction.

  As shown in FIGS. 8 and 9, in addition to the lid wall 66 and the annular wall 67, the wiring case 62 is formed along the plane defined by the lateral direction and the height direction from the tip of the annular wall 67. It has a second flange portion 68 extending in a direction away from the center. The second flange portion 68 is formed on each of the upper wall 67a, the right wall 67d, the lower wall 67b, and the left wall 67c of the annular wall 67 to form an annular shape.

  A plurality of second screw holes 62c extending in the vertical direction are formed in portions of the second flange portion 68 formed on the right wall 67d and the left wall 67c, respectively. A second screw hole 62c is formed in a portion of the lid wall 66 facing the first partition wall 64e. A second screw hole 62c is also formed at a portion of the second flange portion 68 formed on the upper wall 67a. The second screw holes 62c formed in the second flange portion 68 are arranged in the height direction with the second screw holes 62c formed in a portion of the lid wall 66 facing the first partition wall 64e. Each of the plurality of second screw holes 62c opens on the inner surface 62a of the wiring case 62 and the outer surface 62b on the back side thereof.

  The wiring case 62 is provided in the battery case 61 so as to close the opening of the storage space of the battery case 61 and to cover a portion of the battery cell that protrudes out of the opening of the battery case 61. Due to the arrangement of the wiring case 62 in the battery case 61, the inner surface 61a of the battery case 61 where the first screw hole 61c is opened and the inner surface 62a where the second screw hole 62c of the wiring case 62 is opened are vertically opposed. .

  A collar (not shown) is provided between the inner surface 61a of the battery case 61 where the screw holes are opened and the inner surface 62a of the wiring case 62. The collar has a flat shape with a small vertical length (thickness). The collar has an annular shape with a gap. The annular part of the collar is open vertically. The opening of this collar is located between the opening on the inner surface 61a side of the first screw hole 61c and the opening on the inner surface 62a side of the second screw hole 62c.

  The screw member 60b shown in FIGS. 4 and 5 is fastened to each of the plurality of synthetic screw holes formed by vertically arranging the second screw hole 62c, the collar, and the first screw hole 61c. Thereby, the battery case 61 and the wiring case 62 are mechanically connected to each other in a manner approaching each other in the vertical direction. In this connection state, the battery case 61 is housed in the plane of projection of the wiring case 62 in the vertical direction. Further, the first flange portion 65 and the second flange portion 68 are arranged in the vertical direction.

  Note that a thread groove may be formed in at least one of the first screw hole 61c and the second screw hole 62c. When the first screw hole 61c is opened on the outer surface 61b side of the battery case 61 and the tip of the screw shaft of the screw member 60b protrudes outward therefrom, a nut is fastened to the tip of the screw shaft.

  Due to the connection between the battery case 61 and the wiring case 62, the packing 10j provided on the upper end surface 10e of the battery cell is compressed in the vertical direction between the battery cell and the wiring case 62. As a result, a restoring force is generated in the packing 10j in the direction away from the packing 10j along the vertical direction. The battery cell is pressed in the vertical direction by this restoring force. The battery cells are sandwiched between the packing 10j and the bottom wall 63 of the battery case 61. This suppresses a change in the relative positions of the first to fifth battery cells 11 to 15 in the module case 60. In addition, vertical displacement and expansion of the first to fifth battery cells 11 to 15 are suppressed.

  As described above, the battery cell has the first main surface 10a and the second main surface 10b facing in the height direction. The first main surface 10a and the second main surface 10b are larger in area than the other four surfaces. Therefore, the battery cells are easily expanded in the height direction. Due to the expansion in the height direction of the battery cell, the module case 60 also expands in the height direction. The expansion in the height direction of the module case 60 is suppressed by the above-described suppression plate.

  As shown in FIGS. 8 and 9, a plurality of openings for electrically connecting the first to fifth battery cells 11 to 15 and the connection bus bar 70 are formed in the lid wall 66 of the wiring case 62. ing. These openings penetrate the lid wall 66 along the longitudinal direction. The opening is open on the inner surface 62a and the outer surface 62b of the lid wall 66.

  A first opening 66a, a second opening 66b, a third opening 66c, a fourth opening 66d, a fifth opening 66e, and a sixth opening 66f are formed on the lid wall 66 as openings. I have. The first opening 66a and the sixth opening 66f are formed in the lid wall 66 corresponding to the positive electrode terminal 10g and the negative electrode terminal 10h that function as outputs of the battery pack 10. The second opening 66b to the fifth opening 66e are formed in the lid wall 66 corresponding to the positive terminal 10g and the negative terminal 10h related to the electrical series connection of the plurality of battery cells.

  In a state where the wiring case 62 is connected to the battery case 61, the first opening 66a is formed in the lid wall 66 at a position vertically opposed to the negative terminal 10h of the first battery cell 11 in the first direction. The second opening 66b is formed in the lid wall 66 at a portion vertically opposed to the positive terminal 10g of the first battery cell 11 and at a portion vertically opposed to the negative terminal 10h of the second battery cell 12. ing.

  The third opening 66c is formed in the lid wall 66 at a portion vertically opposed to the positive terminal 10g of the second battery cell 12 and at a portion vertically opposed to the negative terminal 10h of the third battery cell 13. ing. The fourth opening 66d is formed in a portion of the lid wall 66 that vertically faces the positive terminal 10g of the third battery cell 13 and a portion that vertically faces the negative terminal 10h of the fourth battery cell 14. ing.

  The fifth opening 66e is formed in the lid wall 66 at a portion vertically opposed to the positive terminal 10g of the fourth battery cell 14 and at a portion vertically opposed to the negative terminal 10h of the fifth battery cell 15 respectively. ing. The sixth opening 66f is formed in the lid wall 66 at a position vertically opposed to the positive electrode terminal 10g of the fifth battery cell 15.

  As described above, on the first stack storage space 64f side of the wiring case 62, the first opening 66a and the fifth opening 66e are arranged in the height direction. The second opening 66b, the fourth opening 66d, and the sixth opening 66f are spaced apart from each other in the horizontal direction in the height direction. Accordingly, on the side of the first stack storage space 64f in the wiring case 62, the first opening 66a and the fifth opening 66e are located between the second opening 66b, the fourth opening 66d, and the sixth opening 66f. Space is configured. This space corresponds to a first space described later.

  On the side of the second stack storage space 64g in the wiring case 62, the second opening 66b and the fourth opening 66d are arranged in the height direction. The third opening 66c is located apart from these in the lateral direction. Thus, on the side of the second stack storage space 64g in the wiring case 62, a space is formed between the second opening 66b, the fourth opening 66d, and the third opening 66c. This space corresponds to a second space described later.

<Connected bus bar>
The connection bus bar 70 includes a first connection bus bar 71, a second connection bus bar 72, a third connection bus bar 73, a fourth connection bus bar 74, a fifth connection bus bar 75, and a sixth connection bus bar 76. The first to sixth connecting bus bars 71 to 76 are provided on the outer surface 62b of the lid wall 66 as shown in FIGS. And a part thereof is provided in the corresponding opening.

  In addition, a plurality of busbar recesses 84 that are locally recessed toward the battery case 61 are formed in the lid wall 66 corresponding to the connection busbars 70. The busbar concave portion 84 is formed so as to be locally concave from the outer surface 62b of the lid wall 66 toward the inner surface 62a in the vertical direction. A first opening 66a to a sixth opening 66f are formed at the bottom of each of the plurality of busbar recesses 84.

  The vertical length of the bottom of the bus bar recess 84 is shorter than the vertical length of each of the positive electrode terminal 10g and the negative electrode terminal 10h. Therefore, the vertical length of each opening is also shorter than the vertical length of each of the positive electrode terminal 10g and the negative electrode terminal 10h. Each of the positive terminal 10g and the negative terminal 10h protrudes out of the module case 60 through each opening.

  The first connection bus bar 71 is provided on the outer surface 62b side of the bus bar recess 84 so as to close the first opening 66a. A portion provided in the first opening 66a of the first connection bus bar 71 is mechanically and electrically connected to the negative terminal 10h of the first battery cell 11 by laser welding or the like.

  The first connection bus bar 71 is formed with a minus connection terminal 71 a extending in a vertical direction away from the first battery cell 11. The negative connection terminal 71a functions as a negative output terminal of the battery pack 10. The negative connection terminal 71a is electrically connected to the housing 87 via a fuse (not shown). Thus, the first connection bus bar 71 is at the ground potential.

  The second connection busbar 72 is provided on the outer surface 62b side of the busbar recess 84 so as to close the second opening 66b. The second connection bus bar 72 has a shape extending in the lateral direction. A portion provided in the second opening 66b of the second connection bus bar 72 is mechanically and electrically connected to each of the positive terminal 10g of the first battery cell 11 and the negative terminal 10h of the second battery cell 12 by laser welding or the like. Is done. Thereby, the first battery cell 11 and the second battery cell 12 are connected in series via the second connection bus bar 72.

  The third connection bus bar 73 is provided on the outer surface 62b side of the bus bar recess 84 so as to close the third opening 66c. The third connection bus bar 73 has a shape extending in the height direction. The portion provided in the third opening 66c of the third connection bus bar 73 is mechanically and electrically connected to each of the positive terminal 10g of the second battery cell 12 and the negative terminal 10h of the third battery cell 13 by laser welding or the like. Is done. Thereby, the second battery cell 12 and the third battery cell 13 are connected in series via the third connection bus bar 73.

  The fourth connection bus bar 74 is provided on the outer surface 62b side of the bus bar recess 84 so as to close the fourth opening 66d. The fourth connection bus bar 74 has a shape extending in the lateral direction. The portion provided in the fourth opening 66d of the fourth connection bus bar 74 is mechanically and electrically connected to each of the positive terminal 10g of the third battery cell 13 and the negative terminal 10h of the fourth battery cell 14 by laser welding or the like. Is done. Thus, the third battery cell 13 and the fourth battery cell 14 are connected in series via the fourth connection bus bar 74.

  The fifth connection bus bar 75 is provided on the outer surface 62b side of the bus bar recess 84 so as to close the fifth opening 66e. The fifth connection bus bar 75 has a shape extending in the height direction. The portion provided in the fifth opening 66e of the fifth connection bus bar 75 is mechanically and electrically connected to each of the positive terminal 10g of the fourth battery cell 14 and the negative terminal 10h of the fifth battery cell 15 by laser welding or the like. Is done. Thus, the fourth battery cell 14 and the fifth battery cell 15 are connected in series via the fifth connection bus bar 75.

  The sixth connection bus bar 76 is provided on the outer surface 62b side of the bus bar recess 84 so as to close the sixth opening 66f. A portion provided in the sixth opening 66f of the sixth connection bus bar 76 is mechanically and electrically connected to the positive terminal 10g of the fifth battery cell 15 by laser welding or the like.

  The sixth connection bus bar 76 is provided with a positive connection terminal 76 a extending in a vertical direction away from the fifth battery cell 15. The positive connection terminal 76a functions as a positive output terminal of the battery pack 10.

  As described above, the first connection bus bar 71 and the fifth connection bus bar 75 are located on the right wall 67d side of the lid wall 66 as shown in FIGS. The second connection bus bar 72, the fourth connection bus bar 74, and the sixth connection bus bar 76 are located on the center side of the lid wall 66 in the lateral direction. Thus, a space is formed between the right wall 67d side of the lid wall 66 and the center side. Hereinafter, this space is referred to as a first space.

  Further, the third connection bus bar 73 and the fourth connection bus bar 74 are located on the left wall 67c side of the lid wall 66. Thereby, a space is formed between the left wall 67c side and the center side of the lid wall 66. Hereinafter, this space is referred to as a second space.

  Further, in the following, for convenience of description, a portion of the upper wall 67a on the first stack storage space 64f side is referred to as a first upper wall 81. A portion of the upper wall 67a on the side of the second stack storage space 64g is referred to as a second upper wall 82. A portion of the upper wall 67a between the first stack storage space 64f and the second stack storage space 64g is referred to as a third upper wall 83.

  As described above, the first upper wall 81 is separated from the lower wall 64b in the height direction than the second upper wall 82. Therefore, the third upper wall 83 extends along the height direction.

<Sensor part>
Next, the sensor unit 40 will be described with reference to FIGS.

  As described above, the connection bus bars 70 include the first connection bus bar 71 to the sixth connection bus bar 76. The voltage sensor 41 has six voltage wires 41a, one ends of which are electrically connected to the first to sixth connection bus bars 71 to 76 independently. The other ends of the six voltage wires 41a are connected to the BMU 22. As a result, the voltages detected by the six voltage wires 41a are input to the BMU 22. The voltage wiring 41a is an insulated wire.

  One end of each of the four voltage wires 41 a connected to the first connection bus bar 71, the fourth connection bus bar 74, the fifth connection bus bar 75, and the sixth connection bus bar 76 is provided in a first space of the lid wall 66. One end of each of the four voltage wires 41a is bolted to a portion of the corresponding connection bus bar on the first space side. These four voltage wires 41a extend from the corresponding connection bus bar toward the first upper wall 81.

  The two voltage wires 41 a connected to the second connection bus bar 72 and the third connection bus bar 73 are provided in the second space of the lid wall 66. One end of each of the two voltage wires 41a is bolted to a corresponding portion of the connection bus bar on the second space side. These two voltage wires 41a extend from the corresponding connection bus bar toward the second upper wall 82, and then extend to the first upper wall 81 via the third upper wall 83. These two voltage wirings merge with the four voltage wirings extending from the first space toward the first upper wall 81 on the first upper wall 81.

  The temperature sensor 42 has a first thermistor 42a and a second thermistor 42b. Further, the temperature sensor 42 has two temperature wires 42c having one ends connected to the first thermistor 42a and the second thermistor 42b. The other end of each of these two temperature wires 42c is connected to BMU 22. Thus, the temperatures detected by the first thermistor 42a and the second thermistor 42b are input to the BMU 22. The temperature wiring 42c is an insulated wire. The temperature wiring 42c is formed by covering two electrically independent electric wires with an insulating coating.

  As described above, in the first battery stack 101, three battery cells are arranged in the height direction. In the second battery stack 10m, two battery cells are arranged in the height direction. The larger the number of battery cells arranged, the higher the heat value of the battery stack. Conversely, the smaller the number of battery cells arranged, the lower the amount of heat generated by the battery stack. Therefore, the temperature of the first battery stack 10l tends to be higher than that of the second battery stack 10m.

  In the first battery stack 101, the fourth battery cell 14 is located between the first battery cell 11 and the fifth battery cell 15. Therefore, the fourth battery cell 14 is less likely to dissipate heat than the first battery cell 11 and the fifth battery cell 15, and the temperature is likely to rise.

  In the second battery stack 10m, the second battery cells 12 are aligned with the third battery cells 13 in the height direction. As a result, the second battery cell 12 and the third battery cell 13 can easily radiate heat.

  However, the second battery cells 12 are arranged side by side with the first battery cells 11. The fourth battery cells 14 are arranged side by side with the third battery cells 13. Therefore, the heat of the fourth battery cell 14 is easily transmitted to the third battery cell 13. The heat of the fourth battery cell 14 is hardly transmitted to the second battery cell 12. Thus, the temperature of the second battery cell 12 is less likely to rise than that of the third battery cell 13.

  With the configuration described above, the temperature of the fourth battery cell 14 is more likely to rise than the other four battery cells. The temperature of the second battery cell 12 is less likely to rise than the other four battery cells.

  Therefore, by detecting the temperature of the fourth battery cell 14, it is expected that the highest temperature (maximum temperature) among the plurality of battery cells constituting the battery pack 10 can be detected. By detecting the temperature of the second battery cell 12, it is expected that the lowest temperature (minimum temperature) of the plurality of battery cells constituting the battery pack 10 can be detected.

  The first thermistor 42a is provided in the fourth battery cell 14. Accordingly, it is expected that the maximum temperature can be detected by the first thermistor 42a. The second thermistor 42b is provided in the second battery cell 12. Accordingly, it is expected that the lowest temperature can be detected by the second thermistor 42b.

  The temperatures of the battery cells other than the second battery cell 12 and the fourth battery cell 14 are expected to be between the highest temperature and the lowest temperature detected by the first thermistor 42a and the second thermistor 42b. Therefore, the BMU 22 can estimate the temperature of another battery cell based on the maximum temperature and the minimum temperature.

  A temperature wiring 42c connected at one end to a first thermistor 42a for detecting the temperature of the fourth battery cell 14 is provided in the first space. The temperature wiring 42c extends from the first thermistor 42a toward the first upper wall 81. The temperature wiring 42c having one end connected to the second thermistor 42b is provided in the second space. The temperature wiring 42c extends from the second thermistor 42b toward the second upper wall 82, and then extends to the first upper wall 81 via the third upper wall 83. The two temperature wires 42c merge with the six voltage wires on the first upper wall 81.

  The water immersion sensor 43 has a first counter electrode 43a and a second counter electrode 43b. The submerged sensor 43 has two submerged wires 43c, one end of which is connected to the first counter electrode 43a and the second counter electrode 43b. The other end of each of these two submerged wires 43c is connected to the BMU 22. The submerged wiring 43c is an insulated wire.

  The first counter electrode 43a and the second counter electrode 43b are provided in the first space. The first opposing electrode 43a and the second opposing electrode 43b face each other in the first space while being separated in the lateral direction. When there is a liquid such as water containing impurities between the first counter electrode 43a and the second counter electrode 43b, both are conductive. Thereby, the resistance value between the first counter electrode 43a and the second counter electrode 43b changes. This change in resistance is input to the BMU 22 via the two submerged wires 43c.

  As shown in FIG. 2, on the outer surface 62b side of the wiring case 62, an insulating case 69 for covering the connection bus bar 70 and the like is provided. One end of each of the first counter electrode 43a and the second counter electrode 43b is covered with an insulating case 69. However, the other ends of the first opposing electrode 43a and the second opposing electrode 43b are exposed outside the insulating case 69. The other ends of the first counter electrode 43a and the second counter electrode 43b are bent away from the wiring case 62.

  The two submerged wires 43c are provided in the first space. The two submerged wires 43c extend from one ends of the first counter electrode 43a and the second counter electrode 43b toward the first upper wall 81. The two submerged wires 43c join the six voltage wires and the two temperature wires on the first upper wall 81. As described above, ten wires join at the first upper wall 81. Hereinafter, these merged wirings will be referred to as sensor wirings.

  The ten sensor wires joined by the first upper wall 81 are bundled together by a tape 85. These ten sensor wires are fixed to the upper surface 81 a of the first upper wall 81 by the binding band 86. The ten sensor wires extend laterally to the right wall 67d side from the portion fixed by the binding band 86 as shown in FIGS. 4 and 5, and are turned back to approach the left wall 67c side. Extending. Therefore, the ten sensor wires have a U-shape on the upper surface 81a. The other ends of these ten sensor wires are combined by a first connector 48.

  As shown in FIG. 10, the second connector 27 connected to the first connector 48 is provided on the wiring board 21. One surface of the wiring board 21 facing the height direction is opposed to the module case 60 at a distance in the height direction. The second connector 27 is mounted on the back surface 21b on the one back side. In a state where the wiring board 21 is fixed to the housing 87, the back surface 21b and the upper surface 81a are arranged in a horizontal direction. As a result, the first connector 48 and the second connector 27 are opposed to each other in the lateral direction.

  The first connector 48 is moved laterally so as to approach the second connector 27. Thereby, for example, the first connector 48 is inserted into the second connector 27 as shown in FIG. A signal (state signal) detected by the sensor unit 40 can be input to the BMU 22.

<Housing>
Next, the casing 87 will be described in detail. As described above, the housing 87 has the main body 89 and the connecting wall 90. A connection wall 90 is connected to the main body 89. Thus, the housing 87 has a box shape having an opening.

  The main body 89 has a bottom wall 91 and a side wall 92. The inner bottom surface 91a of the bottom wall 91 faces the height direction. The side wall 92 stands in the height direction from the edge of the inner bottom surface 91a. The side wall 92 has a left side wall 92a and a right side wall 92b opposed to each other while being spaced apart in the lateral direction. The side wall 92 has a lower side wall 92c located between the left side wall 92a and the right side wall 92b.

  The left side wall 92a and the right side wall 92b each extend in the vertical direction. The lower side wall 92c extends in the lateral direction and integrally connects the left side wall 92a and the right side wall 92b. As shown in FIG. 2, the left side wall 92a is shorter in the vertical direction than the right side wall 92b. Therefore, a part of the right side wall 92b faces the left side wall 92a in the lateral direction. Note that, for example, in FIG. 11 schematically showing the housing 87, the left side wall 92a and the right side wall 92b are illustrated with the same length.

  As shown in FIG. 2, the main body 89 has a first rib group 93a, a second rib group 93b, and a third rib group 93c arranged side by side in the lateral direction. Each of these three rib groups has a plurality of ribs extending from the inner bottom surface 91a in the height direction. The rib has a cylindrical shape. A bolt hole is opened at the tip end surface of the rib.

  The first rib group 93a has four ribs. These four ribs are arranged vertically. These four ribs are integrally connected to the left side wall 92a.

  The second rib group 93b has five ribs. These five ribs are arranged vertically.

  The third rib group 93c has four ribs. These four ribs are arranged vertically. These four ribs are integrally connected to the right side wall 92b.

  As described above, the region between the left side wall 92a and the right side wall 92b in the horizontal direction on the inner bottom surface 91a is roughly divided into two regions by the three rib groups. That is, a region between the left side wall 92a and the right side wall 92b in the lateral direction on the inner bottom surface 91a is a region between the first rib group 93a and the second rib group 93b, and a region between the second rib group 93b and the third rib group 93b. It is divided into an area between the group 93c. The lateral length of each of these two regions is determined according to the lateral length of the battery stack (battery cell).

  By the way, as shown in FIGS. 4 and 7, two projections 64n projecting outward are formed on the left wall 64c of the battery case 61. The same two protrusions 64n are formed on the right wall 64d. These two protrusions 64n are arranged side by side in the vertical direction. The protrusion 64n formed on the left wall 64c and the protrusion 64n formed on the right wall 64d are arranged in a horizontal direction. Each of the four protrusions 64n is formed with a bolt hole 64o that opens in the height direction.

  As shown in FIG. 7, five through holes 64p that open in the height direction are formed in the first partition wall 64e. These five through holes 64p are arranged in the vertical direction. The opening areas of the five through holes 64p are not uniformly the same. The opening area of the through hole 64p located in the middle of the five through holes 64p arranged in the vertical direction is smaller than that of the other four through holes 64p.

  When the battery module 1 is provided in the housing 87, the bolt holes 64o of the two protrusions 64n formed on the left wall 64c of the battery case 61 and the bolt holes of the four ribs of the first rib group 93a. Two are lined up in the height direction. Similarly, the bolt holes 64o of the two protrusions 64n formed on the right wall 64d of the battery case 61 and two of the four rib bolt holes of the third rib group 93c are arranged in the height direction. . The five ribs of the second rib group 93b pass through the five through holes 64p formed in the first partition wall 64e.

  In this state, the shaft of the bolt 94 is fastened to the bolt hole 64o of the protrusion 64n and the bolt hole of the rib. The shaft of the bolt 94 is fastened to the bolt hole of the middle rib among the five ribs arranged in the vertical direction passing through the through hole 64p. The head of the bolt 94 fastened to the bolt hole 64o and the bolt hole of the rib contacts the projection 64n in the height direction. The head of the bolt 94 fastened to the bolt hole of the rib passing through the through hole 64p comes into contact with the first partition wall 64e in the height direction. Then, a part of each of the first flange portion 65 of the battery case 61 and the second flange portion 68 of the wiring case 62 contacts the inner bottom surface 91 a of the bottom wall 91.

  The battery module 1 is fixed to the main body 89 by the fastening of the bolts 94 described above. The battery module 1 and the main body 89 can conduct heat. The battery module 1 and the main body 89 can actively transfer heat via the air between them. In FIG. 11 schematically showing the housing 87, only the ribs that contribute to the direct fixing of the battery module 1 to the main body 89 are illustrated. Other ribs that do not contribute to the direct fixing of the battery module 1 to the main body 89 are used for the above-described restraint plate and for bolting the wiring board 21 to the main body 89. The bottom wall 91, the left side wall 92a, and the right side wall 92b correspond to fixed walls.

  As described above, the battery case 61 (battery module 1) is mounted in the region between the left side wall 92a and the right side wall 92b arranged in the horizontal direction on the inner bottom surface 91a. When the battery module 1 is mounted on the inner bottom surface 91a, the battery module 1 and the lower side wall 92c are vertically separated from each other. As shown in FIG. 13, between the battery module 1 and the lower side wall 92c, a resin base 88 and a fuse for accommodating the above-described power supply bus bar 50, a first switch 31, a second switch 32, and the like are provided. Hereinafter, the space between the battery module 1 and the lower side wall 92c in the storage space of the pack case 80 is referred to as an arrangement space. The lower wall 92c corresponds to the opposing wall.

  In a region of the inner bottom surface 91a that defines a part of the arrangement space, a heat radiating base 95 protruding toward the opening side (cover side) of the housing 87 along the height direction is formed. The heat radiator 95 of the present embodiment includes a first heat radiator 95a and a second heat radiator 95b that are arranged side by side in the lateral direction. The first switch 31 is mounted on the first radiator 95a. The second switch 32 is mounted on the second radiator 95b. Therefore, the heat generated by the first switch 31 is conducted to the first radiator 95a. The heat generated by the second switch 32 is conducted to the second radiator 95b.

  Further, a plurality of body flange portions 96 for connecting to the body of the vehicle are integrally connected to the bottom wall 91. The body flange portion 96 and the vehicle body are mechanically and thermally connected via bolts. Thereby, battery pack 100 is fixed to the vehicle.

  As shown in the (a) column of FIGS. 11 and 12, a surface (end surface 89 a) of the bottom wall 91, the left side wall 92 a, and the right side wall 92 b on the side opposite to the connection end with the lower side wall 92 c. Are flush with each other in a plane facing the vertical direction. The end surfaces 89a of these three walls have a substantially C-shape in a plane perpendicular to the longitudinal direction.

  Each of the bottom wall 91, the left side wall 92a, and the right side wall 92b is formed with a bolt hole 89b opening to the end face 89a. Two bolt holes 89b are opened in the end surface 89a of each of the left side wall 92a and the right side wall 92b. One bolt hole 89b is opened in the end surface 89a of the bottom wall 91.

  Further, a groove 89c for providing a sealing material 97 described later is formed in the end surface 89a of each of the bottom wall 91, the left wall 92a, and the right wall 92b. The groove 89c is shown by a broken line in the column (a) of FIG. The groove 89c is formed so as to extend continuously from the left side wall 92a to the right side wall 92b via the bottom wall 91 along the shape of the end face 89a. The groove 89c is located closer to the storage space of the pack case 80 than the opening of the bolt hole 89b. In other words, the groove 89c is located on the inner side of each of the left side wall 92a and the right side wall 92b that define a part of the storage space of the pack case 80. The groove 89c is located closer to the inner bottom surface 91a than the outer bottom surface 91b of the bottom wall 91.

  As shown in FIG. 11 and FIG. 12B, the connecting wall 90 has a flat plate shape facing in the vertical direction. The connecting wall 90 has a heat transfer surface 90a and a heat dissipation surface 90b facing in the vertical direction. The connection wall 90 is formed with five bolt holes 90c penetrating the heat transfer surface 90a and the heat dissipation surface 90b. Two bolt holes 90c are arranged along two edges along the height direction of the connecting wall 90. One bolt hole 90c is located on one of two edges along the lateral direction of the connecting wall 90. The heat transfer surface 90a corresponds to the inner wall surface. The heat radiation surface 90b corresponds to the outer wall surface.

  A linear sealing member 97 is provided on the heat transfer surface 90a. The sealing material 97 is located inside the opening of the bolt hole 90c in the heat transfer surface 90a. In other words, the seal member 97 is located closer to the heat transfer sheet 98 described later than the opening of the bolt hole 90c in the heat transfer surface 90a.

  The heat transfer surface 98 a is provided with a heat transfer sheet 98 for conducting heat of the battery cells to the connection wall 90. The heat transfer sheet 98 is made of a resin having heat conductivity and insulating properties. The heat transfer sheet 98 has a property of being easily deformed by application of an external force. The heat transfer sheet 98 has a lower thermal conductivity than the connecting wall 90. The thickness of the heat transfer sheet 98 in the vertical direction is smaller than the thickness of the connecting wall 90 in the vertical direction.

  The heat transfer sheet 98 has a plurality of heat transfer sheet cells corresponding to the plurality of battery cells. That is, the heat transfer sheet 98 includes a plurality of heat transfer sheet cells, a first heat transfer sheet cell 98a, a second heat transfer sheet cell 98b, a third heat transfer sheet cell 98c, a fourth heat transfer sheet cell 98d, and a plurality of heat transfer sheet cells. It has five heat transfer sheet cells 98e. These five heat transfer sheet cells are separated on the heat transfer surface 90a.

  As shown in the column (b) of FIG. 12, the first heat transfer sheet cell 98a, the fourth heat transfer sheet cell 98d, and the fifth heat transfer sheet cell 98e are arranged separately in the height direction. The second heat transfer sheet cells 98b and the third heat transfer sheet cells 98c are arranged in order in the height direction so as to be separated from each other. The first heat transfer sheet cells 98a and the second heat transfer sheet cells 98b are arranged side by side in the lateral direction. The fourth heat transfer sheet cell 98d and the third heat transfer sheet cell 98c are arranged side by side in the lateral direction. Each of these five heat transfer sheet cells is individually adhered to the lower end face 10f of the above-mentioned five battery cells.

<Connection between main body and connecting wall>
As shown in FIG. 13, the connection wall 90 is connected to the main body 89 after the battery module 1, the first switch 31 and the second switch 32, the resin base 88 and the fuse are fixed to the main body 89. Will be In FIG. 13, the battery cells in the module case 60 are shown by solid lines in order to avoid the notation being complicated. 13 and 15, illustration of the connection bus bars 70 connected to each battery cell is omitted in order to avoid complication of the notation due to the overlapping of the plurality of connection bus bars 70. The plurality of connecting bus bars 70 are located on the arrangement space side in the storage space.

  As shown in FIG. 14, when the battery module 1 is fixed to the main body 89, the bottom wall 63 of the battery case 61 is located on the end face 89 a side of the main body 89. Therefore, the opening window 63a formed in the bottom wall 63 is also located on the end face 89a side. As shown in the column (a) of FIG. 15, an opening window 63a formed in a portion of the bottom wall 63 that defines a part of the first stack storage space 64f is located on the right wall 92b side. An opening window 63a formed in a portion of the bottom wall 63 that defines a part of the second stack storage space 64g is located on the left wall 92a side. The drawings shown in the column (b) of FIG. 15 and the column (b) of FIG. 12 are the same.

  As shown in FIG. 14, the connecting wall 90 is provided on the main body portion 89 so as to face the outer surface 61b of the bottom wall 63 and the end surface 89a of the main body portion 89, respectively. Due to the arrangement of the connecting wall 90 on the main body 89, the opening of the bolt hole 90c formed on the heat transfer surface 90a of the connecting wall 90 and the opening of the bolt hole 89b formed on the end surface 89a are aligned in the vertical direction. The shaft of a bolt 99 shown in FIGS. 13 and 14 is fastened to each of the five synthetic screw holes formed by arranging the bolt holes 90c and the bolt holes 89b in the vertical direction. The head of the bolt 99 fastened to the bolt hole 90c and the bolt hole 89b is in vertical contact with the heat radiation surface 90b. As a result, the main body 89 and the connecting wall 90 are mechanically connected to each other in such a manner as to approach each other in the vertical direction.

  Due to the connection between the main body 89 and the connection wall 90, the heat transfer sheet 98 provided on the heat transfer surface 90a of the connection wall 90 is provided in the stack storage space of the battery case 61 via the opening window 63a. Then, as shown in FIGS. 16 and 17, the heat transfer sheet 98 contacts the lower end face 10f of the battery cell. Specifically, the first heat transfer sheet cell 98a to the fifth heat transfer sheet cell 98e individually contact the lower end surfaces 10f of the first to fifth battery cells 11 to 15, respectively. The contact area is the same.

  As described above, the battery module 1 is fixed to the main body 89. Therefore, the connection of the connection wall 90 to the main body 89 compresses the heat transfer sheet 98 in the vertical direction between the lower end face 10 f of the battery cell and the heat transfer surface 90 a of the connection wall 90. Thereby, the heat transfer sheet 98 comes into close contact with the battery cell. The heat generated in the battery cells is conducted to the connection wall 90 via the heat transfer sheet 98.

  Further, by connecting the connecting wall 90 to the main body 89, the linear sealing material 97 provided on the heat transfer surface 90 a of the connecting wall 90 is provided in the groove 89 c formed on the end face 89 a of the main body 89. Then, the sealing material 97 is compressed in the vertical direction between the heat transfer surface 90a and the wall surface that defines the groove 89c. As a result, the sealing material 97 comes into close contact with each of the main body portion 89 and the connecting wall 90.

<Effects>
Next, the operation and effect of the battery pack 100 according to the present embodiment will be described.

  The battery module 1 is fixed to the main body 89 as described above. A connecting wall 90 is connected to the main body 89. A heat transfer sheet 98 is sandwiched between the battery module 1 (battery cell) and the connection wall 90. According to this, the heat generated in the battery module 1 is transferred to the main body 89 and the connecting wall 90. Thereby, a decrease in the heat radiation performance of the battery module 1 is suppressed.

  The lower wall 92c of the main body 89 and the battery module 1 are separated in the vertical direction. Thus, unlike the configuration in which the battery module is sandwiched between the lower wall and the connection wall, for example, in the battery pack 100, an arrangement space is formed between the lower wall 92c and the battery module 1. In this arrangement space, a resin base 88 for housing the power supply bus bar 50, a fuse, the first switch 31, the second switch 32, and the like can be arranged. In this way, the limitation on the arrangement of members in the pack case 80 is eased. Furthermore, the positive electrode terminal 10g and the negative electrode terminal 10h of the battery cell can be provided on the arrangement space side without contact with the lower wall 92c.

  The power supply bus bar 50 and the first switch 31 and the second switch 32 are provided in the arrangement space. Thereby, the power supply bus bar 50 and the first switch 31 and the second switch 32 are separated from the connection wall 90 via the battery module 1. Therefore, the heat generated due to the energization of the power supply bus bar 50 and the first switch 31 and the second switch 32 is suppressed from being transferred to the connection wall 90.

  The positive electrode terminal 10g and the negative electrode terminal 10h of the battery cell, and the connection bus bar 70 connected to these electrode terminals are located on the arrangement space side. Thereby, the connection portion between the electrode terminal and the connection bus bar 70 is separated from the connection wall 90. Therefore, the heat generated due to the contact resistance and energization at the connection portion is prevented from being transmitted to the connection wall 90.

  By suppressing the heat transfer to the connection wall 90 described above, it is possible to prevent the heat transfer between the connection wall 90 and the battery module 1 from being hindered.

  Each of the plurality of battery cells is in contact with the heat transfer sheet 98. This suppresses a difference in thermal resistance between each of the plurality of battery cells and the connection wall 90. For this reason, a variation in the temperature of the plurality of battery cells is suppressed.

  The heat transfer sheet 98 has a plurality of heat transfer sheet cells, each of which is individually in contact with each of the plurality of battery cells. And a plurality of heat transfer sheet cells are separated.

  According to this, for example, water droplets adhering to the battery cells due to dew condensation or the like are suppressed from being in a mode of bridging the plurality of battery cells via the heat transfer sheet cells. The floating charge of the battery cell is suppressed from flowing between the plurality of battery cells via the water droplet. Corrosion of the battery cell due to the flow of the floating charge is suppressed.

  Due to the connection of the connecting wall 90 to the main body 89, the sealing material 97 is compressed in the vertical direction between the wall surface defining the groove 89 c formed on the end face 89 a of the main body 89 and the heat transfer surface 90 a of the connecting wall 90. You. As a result, the sealing material 97 is brought into close contact with each of the groove 89c and the heat transfer surface 90a, and the gap between the end surface 89a and the heat transfer surface 90a is sealed.

  According to this, the liquid such as water is suppressed from entering the storage space inside the pack case 80 from the gap between the main body 89 and the connection wall 90.

  The heat transfer sheet 98 (heat transfer sheet cell) has a lower thermal conductivity than the connecting wall 90. The thickness of the heat transfer sheet 98 in the vertical direction is smaller than the thickness of the connecting wall 90 in the vertical direction. According to this, for example, as compared with a configuration in which the heat transfer sheet is thicker in the vertical direction than the connection wall, the thermal resistance between the heat transfer sheet and the connection wall interposed between the battery module 1 and the external atmosphere increases Is suppressed. A decrease in the heat radiation performance of the battery module 1 is suppressed.

  As described above, the preferred embodiments of the present disclosure have been described. However, the present disclosure is not limited to the above-described embodiments, and can be implemented with various modifications without departing from the gist of the present disclosure. It is.

(First Modification)
In the present embodiment, an example is shown in which the first heat transfer sheet cell 98a to the fifth heat transfer sheet cell 98e have the same physique as shown in, for example, the column (b) of FIG. 12 and FIG. Therefore, the example in which the contact area between each of the first heat transfer sheet cell 98a to the fifth heat transfer sheet cell 98e and each of the first to fifth battery cells 11 to 15 is the same has been described.

  However, for example, as shown in FIG. 18, the first heat transfer sheet cell 98a to the fifth heat transfer sheet cell 98e may have different physical sizes. Therefore, the contact area between each of the first heat transfer sheet cell 98a to the fifth heat transfer sheet cell 98e and each of the first to fifth battery cells 11 to 15 may be different.

  In the modification shown in FIG. 18, among the three heat transfer sheet cells bonded to the three battery cells constituting the first battery stack 10l, the fourth heat transfer sheet cell 98d is larger than the other two heat transfer sheet cells. The physique of the plane facing the vertical direction is larger. Therefore, the contact area of the fourth heat transfer sheet cell 98d with the fourth battery cell 14 is larger than the contact area of the other two heat transfer sheet cells with the other two battery cells. As a result, the fourth battery cell 14 conducts heat more easily to the connection wall 90 than the other two battery cells.

  As described above, the fourth battery cell 14 is located between the other two battery cells. Therefore, the temperature of the fourth battery cell 14 tends to increase. However, as described above, the fourth battery cell 14 easily conducts heat to the connection wall 90 via the fourth heat transfer sheet cell 98d. For this reason, the occurrence of variations in the temperatures of the three battery cells constituting the first battery stack 10l is suppressed. As described above, when there is a battery cell that easily generates heat due to the arrangement of the battery cell or the like, a configuration in which the contact area with the heat transfer sheet cell increases as the calorific value increases. . Of course, when the contact area between the battery cell and the heat transfer sheet cell increases, the contact area between the battery cell and the connection wall 90 also increases to the same extent.

(Second Modification)
In the present embodiment, an example is shown in which the heat transfer surface 90a of the connecting wall 90 is flat in the direction facing the vertical direction as shown in, for example, the column (b) of FIG. 12 and FIG. However, for example, as shown in FIG. 19, the heat transfer surface 90a is formed with an inner groove portion 90d which is locally recessed in a direction from the heat transfer surface 90a toward the heat dissipation surface 90b, so that the heat transfer surface 90a has locally unevenness. May be formed. The inner groove 90d corresponds to the inner groove.

  In the modification shown in FIG. 19, an inner groove 90d is formed between a plurality of heat transfer sheet cells arranged in the height direction on the heat transfer surface 90a. Specifically, between the first heat transfer sheet cell 98a and the fourth heat transfer sheet cell 98d, between the fourth heat transfer sheet cell 98d and the fifth heat transfer sheet cell 98e, and the second heat transfer sheet cell 98e. An inner groove 90d is formed between the sheet cell 98b and the third heat transfer sheet cell 98c.

  According to this, water droplets adhering to the battery cells due to dew condensation or the like can be caused to flow not to the battery cells arranged side by side in the height direction but to the inner groove portion 90d located between the two battery cells. This suppresses the plurality of battery cells from being electrically connected via the water droplets. Corrosion of the battery cell due to the flow of the floating charge between the battery cells via the water droplet is suppressed.

(Third Modification)
In the present embodiment, for example, as shown in FIG. 14 and the like, an example is shown in which the heat radiation surface 90b of the connecting wall 90 is flat in the direction facing the vertical direction. However, for example, as shown in FIG. 20, the heat radiation surface 90b is locally formed with an outer groove portion 90e that is locally concave in a direction from the heat radiation surface 90b to the heat transfer surface 90a. It may have a shape. The outer groove 90e corresponds to an outer groove.

  In the modification shown in FIG. 20, the same number of outer grooves 90e as the heat transfer sheet cells are formed on the heat dissipation surface 90b. The outer groove 90e and the heat transfer sheet cells are arranged in the vertical direction. The formation of the outer groove 90e increases the area of the heat radiation surface 90b. Thereby, heat radiation through the heat transfer sheet cells of the battery module 1 and the connection wall 90 is promoted.

(Fourth modification)
For example, as shown in FIGS. 21 and 22, a heat radiating fin 90f may be provided on the heat radiating surface 90b. In the modified examples shown in FIGS. 21 and 22, the radiation fins 90f extend in the height direction. A plurality of radiation fins 90f are arranged in the horizontal direction.

  In the portion of the connecting wall 90 that vertically opposes the first battery stack 10l, more heat dissipating fins 90f are formed than in the portion of the connecting wall 90 that vertically opposes the second battery stack 10m. This promotes heat dissipation through the connection wall 90 of the first battery stack 10l, which generates heat more easily than the second battery stack 10m. The occurrence of temperature variations in the three battery cells of the first battery stack 10l and the two battery cells of the second battery stack 10m is suppressed.

(Fifth Modification)
For example, as shown in FIG. 23, a configuration in which the protruding portion is provided in the module case 60 by protruding the heat transfer surface 90 a side of the connection wall 90 may be adopted. In the case of such a configuration, the length of the connecting wall 90 in the vertical direction is increased. The rigidity of the connecting wall 90 increases. Therefore, the deformation of the connecting wall 90 due to the pressing of the connecting wall 90 to the battery module 1 via the heat transfer sheet 98 is suppressed.

(Sixth modification)
In the present embodiment, an example in which the battery module 1 has two battery stacks of the first battery stack 10l and the second battery stack 10m has been described. However, for example, as shown in FIGS. 24 to 26, the battery module 1 can adopt a configuration having one battery stack.

  In the modification shown in FIG. 24, a plurality of battery cells are arranged in the height direction. The upper end face 10e of the battery cell is located on the left wall 92a side. An opening window 63a is formed in the left wall 64c of the battery case 61. By connecting the connection wall 90 to the main body 89, the heat transfer sheet cell comes into contact with the first side surface 10c or the second side surface 10d of the battery cell. In the modification shown in FIG. 24, the first side surface 10c of the fifth battery cell 15 contacts the fifth heat transfer sheet cell 98e.

  In the modification shown in FIG. 25, a plurality of battery cells are arranged in a horizontal direction. The upper end surface 10e of the battery cell is located on the lower wall 92c side. By connecting the connecting wall 90 to the main body 89, the heat transfer sheet cell comes into contact with the lower end face 10f of the battery cell.

  In the modification shown in FIG. 26, a plurality of battery cells are arranged in a horizontal direction. The upper end surface 10e of the battery cell is located on the cover side. An opening window 63a is formed in the left wall 64c of the battery case 61. The heat transfer sheet 98 is not divided into a plurality of heat transfer sheet cells. When the connection wall 90 is connected to the main body 89, one heat transfer sheet 98 comes into contact with the first side surface 10c or the second side surface 10d of the plurality of battery cells constituting the battery stack. In the modification shown in FIG. 26, the first side surface 10c of each of the first battery cell 11, the third battery cell 13, and the fifth battery cell 15 contacts the heat transfer sheet 98. The second side surface 10d of each of the second battery cell 12 and the fourth battery cell 14 contacts the heat transfer sheet 98. Needless to say, also in this modification, a configuration in which the heat transfer sheet 98 is divided into a plurality of heat transfer sheet cells can be adopted.

(Seventh modification)
In the present embodiment, an example in which the battery pack 10 has five battery cells has been described. However, the battery pack 10 only needs to have two or more battery cells, and is not limited to the above example. Also, one or three or more battery stacks can be employed.

(Other modifications)
In the present embodiment, an example has been described in which the vehicle equipped with the power supply system 200 has an idle stop function. However, the vehicle on which the power supply system 200 is mounted is not limited to the above example. For example, a hybrid vehicle or an electric vehicle can be adopted. In this case, the starter motor 120 and the rotating electric machine 130 shown in the present embodiment replace the motor generator.

  In the present embodiment, an example has been described in which the heat transfer sheet 98 contacts the battery cell. However, the heat transfer sheet 98 only needs to contact the battery module 1 and is not limited to the above example. For example, a configuration in which the heat transfer sheet 98 is in contact with the module case 60 may be employed.

  In the present embodiment, an example has been shown in which the battery module 1 is fixed to the bottom wall 91, the left side wall 92a, and the right side wall 92b of the main body 89 with bolts 94, respectively. However, the battery module 1 need not be fixed to all three walls. For example, a configuration in which the battery module 1 is fixed to only the bottom wall 91 by bolts 94 as shown in FIGS. Although not shown, a configuration in which the battery module 1 is fixed to at least one of the left side wall 92a and the right side wall 92b may be employed.

DESCRIPTION OF SYMBOLS 1 ... Battery module, 10e ... Top surface, 10g ... Positive electrode terminal, 10h ... Negative electrode terminal, 11 ... 1st battery cell, 12 ... 2nd battery cell, 13 ... 3rd battery cell, 14 ... 4th battery cell, 15 ... Fifth battery cell, 31 ... first switch, 32 ... second switch, 50 ... power supply bus bar, 51 ... first power supply bus bar, 52 ... second power supply bus bar, 53 ... third power supply bus bar, 54 ... fourth power supply bus bar, Reference numeral 60: module case, 61: battery case, 62: wiring case, 72: second connection bus bar, 73: third connection bus bar, 74: fourth connection bus bar, 75: fifth connection bus bar, 87: housing, 89 ... Main body, 90 ... connecting wall, 90a ... heat transfer surface, 90b ... heat dissipation surface, 90d ... inner groove, 90e ... outer groove, 90f ... heat dissipation fin, 91 ... bottom wall, 92a ... left wall, 92b ... right wall, 92c … Lower wall Reference numeral 97: sealing material, 98: heat transfer sheet, 98a: first heat transfer sheet cell, 98b: second heat transfer sheet cell, 98c: third heat transfer sheet cell, 98d: fourth heat transfer sheet cell, 98e ... 5 heat transfer sheet cells, 100: battery pack, 110: lead storage battery, 120: starter motor, 130: rotating electric machine, 140: engine, 150: electric load, 200: power supply system

Claims (12)

A battery module (1) in which a plurality of battery cells (11 to 15) are housed in a sensor housing (60);
A main body part (89) including a fixed wall (91, 92a, 92b) to which the battery module is fixed, and a facing wall (92c) standing up from the fixed wall and facing the battery module while being spaced apart from the battery module;
A connection wall (90) connected to the main body in a manner approaching the opposing wall via the battery module;
A battery pack comprising: a heat transfer sheet (98) sandwiched between the battery module and the connection wall. A power supply bus bar (50 to 54) for connecting the battery module to an external device (110, 120, 130, 140, 150);
The battery pack according to claim 1, wherein the power supply bus bar is provided in an arrangement space between the battery module and the opposed wall in the main body. A switch (31, 32) connected to the power supply bus bar for controlling connection between the battery module and the external device;
The battery pack according to claim 2, wherein the switch is provided in the arrangement space. Electrode terminals (10g, 10h) are formed on an end surface (10e) of the battery cell on the side of the facing wall,
4. The battery pack according to claim 2, wherein the battery module has connection bus bars (72 to 75) for connecting electrode terminals of the plurality of battery cells in series. 5.   The battery pack according to claim 2, wherein the heat transfer sheet is in contact with each of the plurality of battery cells. The heat transfer sheet has a plurality of heat transfer sheet cells (98a to 98e) provided for each of the plurality of battery cells,
The battery pack according to claim 5, wherein each of the plurality of heat transfer sheet cells is provided on the inner wall surface (90a) of the connection wall on the side of the battery module, so as to be separated from each other.   The battery pack according to claim 6, wherein an inner groove (90d) spaced from the battery module is formed between the plurality of heat transfer sheet cells on the inner wall surface. At least three battery cells are arranged in the sensor housing;
The contact area between the battery cell located inside and the heat transfer sheet cell among the at least three battery cells arranged in line is larger than the contact area between the battery cell located on the end side and the heat transfer sheet cell. The battery pack according to claim 6, wherein the battery pack is larger.   The battery pack according to any one of claims 1 to 8, wherein an outer groove (90e) is formed in an outer wall surface (90b) of the connection wall on the back side of the inner wall surface (90a) on the battery module side.   The battery pack according to any one of claims 1 to 9, wherein a radiating fin (90f) is formed on an outer wall surface (90b) of the connection wall on the back side of the inner wall surface (90a) on the battery module side.   The seal member (97) according to any one of claims 1 to 10, further comprising a sealing material (97) sandwiched between the main body portion and the connection wall to seal a gap between the main body portion and the connection wall. Battery pack.   The battery pack according to any one of claims 1 to 11, wherein a thickness of the heat transfer sheet in a direction in which the opposed wall and the connecting wall are arranged via the battery module is smaller than a thickness of the connecting wall.

Images