JP7087769B2 - Battery pack - Google Patents

Description

The disclosures described herein relate to battery packs.

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

Japanese Unexamined Patent Publication No. 2011-34775

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

Therefore, it is an object of the disclosure described in the present specification to provide a battery pack in which deterioration of heat dissipation 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 fixed wall (91, 92a, 92b) to which the battery module is fixed, and a main body portion (89) having an facing wall (92c) that stands up from the fixed wall and faces the battery module separately from the fixed wall.
A connecting wall (90) connected to the main body in a manner approaching the facing wall via the battery module, and
A heat transfer sheet (98) sandwiched between the battery module and the connecting wall,
It has a power supply bus bar (50 to 54) that connects the battery module and external devices (110, 120, 130, 140, 150) .
The power supply bus bar is provided in the arrangement space between the battery module and the facing wall in the main body .

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

Further, in the present disclosure, the facing wall (92c) and the battery module (1) are separated from each other. The battery module (1) is fixed to a fixed wall (91, 92a, 92b). The connecting wall (90) is connected to the main body (89) in a manner of approaching the facing wall (92c) via the battery module (1).

Therefore, in the present disclosure, unlike the configuration in which the battery module is sandwiched between the facing wall and the connecting wall, for example, a space is formed between the facing 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 of the member arrangement in the main body portion (89) is relaxed.

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

It is a circuit diagram for demonstrating a power supply system. It is an exploded perspective view for demonstrating a battery pack. It is a perspective view for demonstrating a battery pack. It is a perspective view for demonstrating a battery module. It is an exploded perspective view for demonstrating a battery module. It is a figure for demonstrating a battery case. It is a figure for demonstrating a battery case. It is a figure for demonstrating a wiring case. It is a figure for demonstrating a wiring case. It is a perspective view for demonstrating the arrangement of a battery module and a circuit board. It is a top view which shows the housing schematically. It is a figure which shows the housing schematically. It is a top view for schematically explaining the connection between a main body part and a connecting wall. It is a side view for schematically explaining the connection between a main body part and a connecting wall. It is a figure which shows schematically the housing in which the battery module is mounted. It is a top view which shows typically the battery pack. It is a side view which shows typically the battery pack. It is a side view for demonstrating the modification of the heat transfer sheet cell. It is a side view for demonstrating the deformation example of the connecting wall. It is a side view for demonstrating the deformation example of the connecting wall. It is a side view for demonstrating the deformation example of the connecting wall. It is a rear view for demonstrating the radiating fin. It is a figure for demonstrating the deformation example of the connecting wall. It is a top view which shows the modification of the battery pack schematically. It is a top view which shows the modification of the battery pack schematically. It is a top view which shows the modification of the battery pack schematically.

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

(First Embodiment)
The battery pack 100 according to the present embodiment and the power supply system 200 including the battery pack 100 will be described with reference to FIGS. 1 to 17.

<Overview of power supply system>
The power supply system 200 is mounted on the vehicle. The power supply system 200 is composed of a plurality of in-vehicle devices mounted on the vehicle and a battery pack 100. There is a lead storage battery 110 as one of the in-vehicle devices. The battery pack 100 has an assembled battery 10. The power supply system 200 constructs a dual power supply system by the lead storage battery 110 and the assembled battery 10.

Another in-vehicle device is the engine 140. The vehicle equipped with the power supply system 200 has an idle stop function of stopping the engine 140 when a predetermined stop condition is satisfied and restarting 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 rotary electric machine 130, an electric load 150, an upper ECU 160, and an MGE ECU 170 in addition to the lead storage battery 110 and the engine 140 described above. The lead-acid battery 110, the starter motor 120, and the electric load 150 are each electrically connected to the battery pack 100 via the first wire harness 210. The rotary 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 rotary electric machine 130, the engine 140, and the electric load 150 correspond to external devices.

The upper ECU 160 and the MG ECU 170 are electrically connected to each of 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-acid battery 110 and the battery pack 100 via wiring (not shown).

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

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

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

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

The power converter converts the DC voltage supplied from at least one of the lead-acid battery 110 and the battery pack 10 of the battery pack 100 into an AC voltage. This AC voltage is supplied to the rotary electric machine 130. As a result, the rotary electric machine 130 runs power.

The rotary electric machine 130 is connected to the engine 140. The rotary electric machine 130 and the engine 140 can mutually transmit rotational energy via a belt or the like. The rotational energy generated by the power running of the rotary electric machine 130 is transmitted to the engine 140. This promotes the rotation of the engine 140. 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 rotary electric machine 130 not only assists the vehicle running, but also functions to rotate the 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 rotary electric machine 130 generates an AC voltage by power generation. This AC voltage is converted into a DC voltage by a power converter. This DC voltage is supplied to the battery pack 100, the lead storage battery 110, and the electric load 150, respectively.

The engine 140 produces propulsive force for the vehicle by driving the fuel by combustion. As described above, when the engine 140 is started, the crankshaft is rotated by the starter motor 120. However, when the engine 140 is stopped once by the idle stop and then restarted, if the above-mentioned predetermined starting conditions are satisfied, the crankshaft is rotated by the rotary electric machine 130.

The electrical load 150 has a general load 151 and a protective 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, which do not have to have a constant power supply. The protective load 152 includes motorized shift positions, motorized power steering (EPS), brakes (ABS), door locks, navigation systems, and in-vehicle devices such as audio that are required to have a constant power supply. The protective load 152 exemplified here has a property of switching from an on state to an off state when the supply voltage falls below the reset threshold value. The protective load 152 includes in-vehicle devices that are more relevant to vehicle travel than the general load 151.

The configuration in which the above-mentioned various in-vehicle devices are included in the general load 151 and the protective load 152 is only an example. Various in-vehicle devices can be appropriately distributed to the general load 151 and the protective load 152 according to changes in the in-vehicle system. For example, a configuration in which EPS and ABS are included in the general load 151 can be adopted.

The upper ECU 160 and the MG ECU 170 are one of various ECUs mounted on the vehicle. These various ECUs are electrically connected to each other via the bus wiring 161 to form an in-vehicle network. By coordinated control of various ECUs, combustion of the engine 140, power running of the rotary electric machine 130, power generation, and the like are controlled. The upper ECU 160 controls the battery pack 100, and the MG ECU 170 controls the rotary electric machine 130.

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

The ECU is an abbreviation for 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 equipped with a computer-readable storage medium. A storage medium is a non-transitional substantive storage medium that stores a computer-readable program non-temporarily. The storage medium may be provided by a semiconductor memory, a magnetic disk, or the like.

<Overview of battery pack>
As shown in FIG. 1, the battery pack 100 includes an assembled battery 10, a circuit board 20, a switch 30, a sensor unit 40, and a power supply bus bar 50. Further, as shown in FIGS. 2 to 4, the battery pack 100 has a module case 60, a connecting bus bar 70, and a pack case 80. In FIGS. 2 and 3, the circuit board 20 and the power supply bus bar 50 are not shown.

The assembled battery 10 has a smaller body size and a lighter weight than the lead storage battery 110. The assembled battery 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 assembled battery 10 are electrically connected to the circuit board 20 via the power supply bus bar 50. This constitutes the electric circuit of the battery pack 100. The sensor unit 40 is electrically connected to this electric circuit.

The electric circuit of the battery pack 100 is electrically connected to the external connection terminal indicated by the 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. Has been done. The second external connection terminal 100b is electrically connected to the rotary electric machine 130 via the second wire harness 220. The third external connection terminal 100c is bolted to the body of the vehicle. The bolt inserted into the third external connection terminal 100c functions to connect the battery pack 100 and the vehicle body. As a result, the battery pack 100 is body grounded.

As shown in FIG. 1, the first wire harness 210 is divided into one for connecting a lead storage battery 110, a starter motor 120, and a general load 151, and one for connecting a protective load 152. The end of the first wire harness 210 connecting the lead-acid battery 110, the starter motor 120, and the general load 151 is bifurcated. One of the bifurcated ends is connected to the first external connection terminal 100a, and the other is connected to the fifth external connection terminal 100e. The end of the first wire harness 210 connecting the protective 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 assembled battery 10 is housed in the battery case 61. Then, the wiring case 62 is connected to the battery case 61. As a result, the assembled battery 10 is housed in the battery case 61 and the wiring case 62. Further, the electrode terminals of the plurality of battery cells constituting the assembled battery 10 are electrically connected in series via the connecting bus bars 70 shown in FIGS. 4 and 5. The module case 60 corresponds to the 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. As a result, the battery module 1 is configured. In FIGS. 4 and 5, the insulation case 69 is omitted in order 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. Further, the pack case 80 has a cover (not shown). A storage space is formed by the housing 87 and the cover. The assembled battery 10, the circuit board 20, the switch 30, the sensor unit 40, the power supply bus bar 50, the module case 60, and the connected bus bar 70 are each housed in this storage space. In addition, a restraining plate (not shown) is stored in this storage space.

The restraining plate is bolted to the housing 87. The battery module 1 is located between the restraining plate and the housing 87 in a state where the restraining plate is fixed to the housing 87. The restraint plate and the housing 87 suppress the displacement and expansion of the battery module 1 in the height direction.

<Battery pack components>
The assembled battery 10 has a plurality of battery cells. Specifically, this battery cell is a lithium ion secondary battery. Lithium-ion secondary batteries generate electromotive voltage through a chemical reaction. Current flows through the battery cell due to the generation of electromotive voltage. As a result, the battery cell generates heat and generates 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 hydrogen secondary battery or an organic radical battery can be adopted.

As described above, the circuit board 20 has a wiring board 21 and a BMU 22. The wiring board 21 is a printed circuit board in which a wiring pattern made of a conductive material is formed on an insulating substrate. A first feeder line 23, a second feeder line 24, and a third feeder 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 this conductive plate. Bolts are passed through the bolt holes of this conductive plate. This bolt is fixed to the housing 87. As a result, the wiring board 21 is mechanically and electrically connected to the housing 87.

As will be described later, the housing 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 this conductive plate as a reference potential.

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

The switch 30 has a first switch 31, a second switch 32, a third switch 33, a fourth switch 34, a fifth switch 35, and a sixth switch 36. The first switch 31 and the second switch 32 are mounted on the housing 87. The third switch 33 and the fourth switch 34, and the fifth switch 35 and the sixth switch 36 are each mounted on the wiring board 21.

Each of the first switch 31 to the fourth switch 34 has a semiconductor switch. Specifically, this semiconductor switch is 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 by inputting a low-level control signal.

As the semiconductor switch included in the first switch 31 to the fourth switch 34, an IGBT or the like can also be adopted. In this case, a diode is connected in parallel to the IGBT.

Each of the fifth switch 35 and the sixth switch 36 is a mechanical relay. Specifically, each of the fifth switch 35 and the sixth switch 36 is a normally closed electromagnetic relay. Therefore, each of the 5th switch 35 and the 6th 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 the input of the 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. The source electrodes of these two MOSFETs are connected to each other. The gate electrodes of the two MOSFETs are electrically independent. MOSFETs have parasitic diodes. The parasitic diodes of the two MOSFETs are connected to each other by the anode electrodes. The gate electrode is electrically connected to the circuit board 20.

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

The third switch 33 has one opening / closing part. The fourth switch 34 has a plurality of opening / closing portions. A plurality of opening / closing portions of the fourth switch 34 are connected in series.

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

Compared to the third switch 33 to the sixth switch 36, a larger current flows through the first switch 31 and the second switch 32 on a time average. Therefore, as described above, the first switch 31 and the second switch 32 have a configuration in which a plurality of opening / closing portions 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 assembled battery 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, current, and voltage of the assembled battery 10. The sensor unit 40 outputs it to the BMU 22 as a status signal of the assembled battery 10. Further, the sensor unit 40 detects the temperature, current, and voltage of the switch 30. The sensor unit 40 outputs it to the BMU 22 as a status signal of the switch 30.

In FIG. 1, as representatives of these plurality of sensors, a voltage sensor 41 that detects the voltage of the assembled battery 10 and a temperature sensor 42 that detects the temperature of the assembled battery 10 are clearly shown.

Further, the sensor unit 40 has a submersion sensor 43 in addition to the above-mentioned various sensors. The resistance value of the submersion sensor 43 changes depending on water or the like. The submersion sensor 43 detects this change in resistance value by the BMU 22. The BMU 22 detects submersion of the battery pack 100 based on whether or not the change in resistance is continued for a predetermined time.

The BMU 22 controls the switch 30 based on at least one of the state signal of the sensor unit 40 and the 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 the BMU 22 controls the opening and closing of the first switch 31, all the semiconductor switches of the first switch 31 are controlled to be in the closed state at the same time or in the open state at the same time. 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 of 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. Simply put, the BMU 22 may control the pulse width of the semiconductor switch.

The BMU 22 determines the state of charge (SOC) of the assembled battery 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 these SOCs and signals (determination information) for determining an abnormality to the upper ECU 160.

The upper 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 various other ECUs. Then, the upper ECU 160 outputs a command signal including the control of the determined switch 30 to the 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 based on the status signal of the submersion sensor, the BMU 22 arbitrarily stops the output of the control signal to the switch 30. As a result, the electrical connection of the assembled battery 10 is cut off.

Further, the BMU 22 limits the driving of the switch 30 when the switch 30 becomes hot. 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 energizing time of the semiconductor switch. As a result, heat generation of the semiconductor switch is suppressed.

The feeding 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 one 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 conductive material in a molten state into a mold. The power supply bus bar 50 can also 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 can be adopted 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 assembled battery 10, and the circuit board 20 and the external connection terminal are electrically connected by these plurality of power supply bus bars. In FIG. 1, each of these feeding bus bars is shown to be thicker than the feeding line of the wiring board 21. These power supply bus bars are provided on the insulating resin base 88, which is schematically shown in FIG. The resin base 88 is arranged to face the wiring case 62 in the vertical direction, which will be described later.

As described above, the module case 60 has a battery case 61, a wiring case 62, and an 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 connected bus bar 70 is formed by the same manufacturing method as the power feeding bus bar 50. The connecting bus bar 70 is provided in the wiring case 62. The connecting bus bar 70 electrically and mechanically connects a plurality of battery cells included in the assembled battery 10.

As described above, the pack case 80 has a housing 87 and a cover. The housing 87 has a main body portion 89 and a connecting wall 90. The main body 89 and the connecting wall 90 can be manufactured by die-casting aluminum. 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 portion 89 has a bottom wall 91 and a side wall 92 that rises from the inner bottom surface 91a of the bottom wall 91. The connecting wall 90 is connected to the bottom wall 91 and the side wall 92. An opening is formed above the bottom wall 91 by the side wall 92 and the connecting wall 90. This opening is covered by a cover. This constitutes a storage space.

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

<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 shown below is made by TIG welding. The connection between each power supply bus bar and the external connection terminal is made by bolting. The connection between each power supply bus bar and the circuit board 20 is made by brazing. In addition, 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 the first power supply bus bar 51. A part of the first power supply bus bar 51 is branched. 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 of the second power supply bus bar 52 is branched. The branch portion 52a of the second power feeding bus bar 52 is electrically connected to one end of the second switch 32.

Further, a part of the second power supply bus bar 52 is branched from the other end of the first switch 31 and the connection portion between 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 assembled battery 10 are electrically connected via the third power supply bus bar 53. A part of the third power supply bus bar 53 is branched. 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 assembled battery 10 is electrically connected to the third external connection terminal 100c.

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

The third internal terminal 26c and the fourth internal terminal 26d of the wiring board 21 are electrically connected to each other via the second feeder 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 feeder line 24. Then, the midpoint between the third internal terminal 26c and the sixth switch 36 on the second feeder line 24 is connected to the midpoint between the third switch 33 and the fourth switch 34 on the first feeder line 23. There is. As a result, the sixth switch 36 is connected in parallel with the third switch 33.

Further, the midpoint between the fourth internal terminal 26d and the sixth switch 36 on the second feeder line 24 is electrically connected to the fifth external connection terminal 100e via the third feeder line 25. A fifth switch 35 is provided on the third feeder line 25. As a result, 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 connected in order in an annular 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 assembled battery 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.

Further, the midpoint between the first switch 31 and the second switch 32 is connected to the midpoint between 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, the electrical connection between the first external connection terminal 100a and the second external connection terminal 100b is controlled by controlling the opening and closing of the first switch 31. In other words, by controlling the opening and closing of the first switch 31, the electrical connection between the lead-acid battery 110 and the rotary electric machine 130 is controlled.

By controlling the opening and closing of the second switch 32, the electrical connection between the second external connection terminal 100b and the assembled battery 10 is controlled. In other words, by controlling the opening and closing of the second switch 32, the electrical connection between the rotary electric machine 130 and the assembled battery 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, by controlling the opening and closing of the fourth switch 34, the electrical connection between the assembled battery 10 and the protective load 152 is controlled.

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, by controlling the opening and closing of the third switch 33, the electrical connection between the lead-acid battery 110 and the protective load 152 is controlled.

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, by controlling the opening and closing of the sixth switch 36, the electrical connection between the rotary electric machine 130 and the protective load 152 is controlled.

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, by controlling the opening and closing of the fifth switch 35, the electrical connection between the rotary electric machine 130 and the lead storage battery 110 is controlled.

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, by controlling the opening and closing of the fifth switch 35 and the sixth switch 36 at the same time, the electrical connection between the protective load 152 and the lead storage battery 110 is controlled.

<Battery pack configuration>
In the following, the three directions 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 top and bottom direction of the vehicle. When the vehicle is parked on a horizontal plane, the height direction is along the vertical direction. The horizontal and vertical directions are along the horizontal direction.

<Assembled battery>
As described above, the assembled battery 10 has a plurality of battery cells. This battery cell has a rectangular parallelepiped shape. Therefore, the battery cell has six sides. 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 surface 10c and a second side surface 10d facing laterally. The battery cell has an upper end surface 10e facing in the vertical direction. Further, as shown in FIG. 13, the battery cell has a lower end surface 10f facing in the vertical direction. Of these six surfaces, the first main surface 10a and the second main surface 10b have a larger area than the other four surfaces. The battery cell has a thin flat shape with a 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 electrode terminal 10g and the negative electrode terminal 10h have a rectangular parallelepiped shape. The positive electrode terminal 10g and the negative electrode terminal 10h project in the vertical direction from the upper end surface 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 so as to be separated from each other 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, a safety valve 10i having low rigidity is locally formed between the positive electrode terminal 10g and the negative electrode terminal 10h on the upper end surface 10e. As mentioned above, the battery cell expands due to the generation of gas. When the internal pressure of the battery cell rises due to the generation of gas, the safety valve 10i is cracked. As a result, the gas in the battery cell is discharged to the outside through the safety valve 10i.

Packing 10j is provided in each non-formed region of the positive electrode terminal 10g, the negative electrode terminal 10h, and the safety valve 10i on the upper end surface 10e. The packing 10j is made of an elastic material such as rubber. The packing 10j forms an annular shape that opens in the vertical direction. The packing 10j has a longer length in the vertical direction 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 assembled battery 10 of the present embodiment has 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 these plurality of battery cells side by side. These plurality of battery cells are electrically connected in series. The first battery cell 11 becomes the battery cell having the lowest potential. The fifth battery cell 15 becomes the battery cell having the highest potential.

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

In the first battery stack 10l, 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 10 m, the second battery cell 12 and the third battery cell 13 are arranged side by side in the height direction. These battery stacks are housed in the battery case 61.

<Battery case>
Next, the battery case 61 will be described with reference to FIGS. 6 and 7. The 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) in 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 in the vertical direction, and a peripheral wall 64 rising in an annular shape in the vertical direction from the inner surface 61a of the bottom wall 63. The bottom wall 63 is formed with an opening window 63a that vertically penetrates the inner surface 61a and the outer surface 61b on the back side thereof.

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. The upper wall 64a, the right wall 64d, the lower wall 64b, and the left wall 64c are connected in this order in the circumferential direction around the vertical direction to form an annular shape.

Further, the battery case 61 has a first partition wall 64e that laterally divides the area surrounded by the annular peripheral wall 64 into two. The area surrounded by the peripheral wall 64 of the battery case 61 by the first partition wall 64e is a first stack storage space 64f for accommodating the first battery stack 10l and a second stack storage space for accommodating the second battery stack 10m. It is divided into 64 g and so on.

Further, the battery case 61 has a second partition wall 64h for dividing the stack storage space into individual storage spaces corresponding to each battery cell. Two second partition walls 64h are provided in the first stack storage space 64f. These two second partition walls 64h are arranged side by side in the first stack storage space 64f so as to be separated from each other in the height direction. The two second partition walls 64h connect the first partition wall 64e and the right wall 64d. As a result, the first stack storage space 64f is divided into a first storage space 64i, a fourth storage space 64l, and a fifth storage space 64m, which are arranged in order from the lower wall 64b toward the upper wall 64a side in the height direction. ..

One second partition wall 64h is provided in the second stack storage space 64g. This 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 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 divided into a second storage space 64j and a third storage space 64k which are arranged in order from the lower wall 64b toward the upper wall 64a side in the height direction.

As shown 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 length of the first stack storage space 64f in the height direction is longer than that of the second stack storage space 64g.

As shown in the column (b) of FIG. 6, the lower wall 64b that divides a part of each of the two stack storage spaces has a shape extending in the lateral direction. Therefore, the position in the height direction of the portion of the lower wall 64b that partitions the first stack storage space 64f and the position in the height direction of the portion that partitions the second stack storage space 64g are equal.

On the other hand, the portion of the upper wall 64a that partitions a part of the first stack storage space 64f is separated from the lower wall 64b in the height direction than the portion that partitions a part of the second stack storage space 64g. ing. A portion of the upper wall 64a between a portion of the first stack storage space 64f and a portion of the second stack storage space 64g extends along the height direction. As a result, 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 shown 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 side by side. An empty space for one storage space is configured on the third storage space 64k side 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 included in the circuit board 20 has a flat plate shape having a thin thickness in the height direction. The side portions of the wiring board 21 along the vertical direction are lined up horizontally with the fifth storage space 64 m.

Each of the above five individual storage spaces is vertically open. A battery cell is inserted from the opening of these storage spaces to the inside thereof. Each battery cell is inserted into the corresponding storage space until the lower end surface 10f of the battery cell comes into contact with the inner surface 61a of the bottom wall 63 of the battery case 61. In this inserted state, the positive electrode terminal 10g and the negative electrode terminal 10h of each battery cell protrude out of the storage space. Further, the upper end surface 10e side 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 out of the battery case 61.

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

In the second stack storage space 64 g, the second main surface 10b of each of the second battery cell 12 and the third battery cell 13 faces each other in the height direction. As a result, the positive electrode terminals 10g and the negative electrode terminals 10h are alternately arranged in the height direction.

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

In addition to the bottom wall 63 and the peripheral wall 64 described above, the battery case 61 extends from the tip of the peripheral wall 64 in a direction away from the center of the battery case 61 along a plane defined by the lateral direction and the height direction. 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 along the vertical direction are formed in the portions of the first flange portion 65 formed on the right wall 64d and the left wall 64c, respectively. The first screw hole 61c is also formed in the first partition wall 64e. Further, 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 hole 61c formed in the first flange portion 65 is aligned with the first screw hole 61c formed in the first partition wall 64e in the height direction. Each of these plurality of first screw holes 61c is open to the inner surface 61a of the battery case 61.

<Wiring case>
Next, the wiring case 62 will be described with reference to FIGS. 8 and 9. The column (a) of FIG. 8 shows a perspective view of the wiring case. Column (b) of FIG. 8 shows a front view of the wiring case. Column (a) in FIG. 9 shows a rear view of the wiring case. Column (b) in 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 the vertical direction away from the battery case 61. As a result, 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 rising 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 upright from the edge of the surface (inner surface 62a) of the lid wall 66 on the battery case 61 side to the battery cell 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. The upper wall 67a, the right wall 67d, the lower wall 67b, and the left wall 67c are connected in this order in the circumferential direction around the vertical direction to form an annular shape. In the plane defined by the lateral and height directions, the annular wall 67 has a shape similar to the peripheral wall 64 of the battery case 61.

Therefore, the upper wall 67a of the annular wall 67 has a lower wall in the height direction of the portion on the first stack storage space 64f side than the portion on the second stack storage space 64g side in the same manner as the upper wall 64a of the peripheral wall 64. It is separated from 64b. The 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. As a result, 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 provided with the wiring case 62 along a 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 along the vertical direction are formed in the 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. Further, a second screw hole 62c is also formed in a portion of the second flange portion 68 formed on the upper wall 67a. The second screw hole 62c formed in the second flange portion 68 is aligned with the second screw hole 62c formed in the portion of the lid wall 66 facing the first partition wall 64e in the height direction. Each of these plurality of second screw holes 62c is open to 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 cover the portion of the battery cell that protrudes from 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 opened by the first screw hole 61c of the battery case 61 and the inner surface 62a opened by the second screw hole 62c of the wiring case 62 face each other in the vertical direction. ..

A collar (not shown) is provided between the inner surface 61a of the battery case 61 having these screw holes and the inner surface 62a of the wiring case 62. The collar has a thin flat shape with a vertical length (thickness). The collar is an annular with a gap. The part forming the ring of the collar is open in the vertical direction. 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 arranging the second screw holes 62c, the collar, and the first screw holes 61c in the vertical direction. As a result, the battery case 61 and the wiring case 62 are mechanically connected in such a manner that they approach each other in the vertical direction. In this connected state, the battery case 61 is housed in the vertical projection plane of the wiring case 62. Further, the first flange portion 65 and the second flange portion 68 are arranged in the vertical direction.

It is sufficient that a screw groove is formed in at least one of the first screw hole 61c and the second screw hole 62c. When the first screw hole 61c opens 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 from the first screw hole 61c, a nut is fastened to the tip of the screw shaft.

By connecting the battery case 61 and the wiring case 62, the packing 10j provided on the upper end surface 10e of the battery cell is vertically compressed between the battery cell and the wiring case 62. As a result, a restoring force is generated on the packing 10j in the direction away from the packing 10j along the vertical direction. This restoring force presses the battery cell in the vertical direction. The battery cell is sandwiched between the packing 10j and the bottom wall 63 of the battery case 61. As a result, fluctuations in the relative positions of the first battery cells 11 to the fifth battery cells 15 in the module case 60 are suppressed. Further, the vertical displacement and expansion of the first battery cell 11 to the fifth battery cell 15 are suppressed.

As described above, the battery cell has a first main surface 10a and a second main surface 10b facing in the height direction. The areas of the first main surface 10a and the second main surface 10b are larger than those of the other four surfaces. Therefore, the battery cell tends to expand in the height direction. The module case 60 also expands in the height direction due to the expansion of the battery cell in the height direction. The expansion of the module case 60 in the height direction is suppressed by the above-mentioned restraining plate.

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

The lid wall 66 is formed with 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 as openings. There is. The first opening 66a and the sixth opening 66f are formed on the lid wall 66 corresponding to the positive electrode terminal 10g and the negative electrode terminal 10h that function as outputs of the assembled battery 10. The second opening 66b to the fifth opening 66e are formed on the lid wall 66 corresponding to the positive electrode terminal 10g and the negative electrode terminal 10h related to the electrical series connection of a 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 at a portion of the lid wall 66 that vertically faces the negative electrode terminal 10h of the first battery cell 11. The second opening 66b is formed in a portion of the lid wall 66 that vertically faces the positive electrode terminal 10g of the first battery cell 11 and a portion that vertically faces the negative electrode terminal 10h of the second battery cell 12. ing.

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

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

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

Further, 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 laterally separated from these. As a result, on the side of the second stack storage space 64g in the wiring case 62, a space is formed between the second opening 66b and the fourth opening 66d and the third opening 66c. This space corresponds to the second space described later.

<Connected bus bar>
The connected bus bar 70 includes a first connected bus bar 71, a second connected bus bar 72, a third connected bus bar 73, a fourth connected bus bar 74, a fifth connected bus bar 75, and a sixth connected bus bar 76. The first connecting bus bar 71 to the sixth connecting bus bar 76 are provided on the outer surface 62b of the lid wall 66 as shown in FIGS. 4 and 5. And a part of it is provided in the corresponding opening.

The lid wall 66 is formed with a plurality of bus bar recesses 84 that are locally recessed on the battery case 61 side corresponding to the connecting bus bar 70. The bus bar recess 84 is formed to be locally recessed from the outer surface 62b of the lid wall 66 toward the inner surface 62a in the vertical direction. The first opening 66a to the sixth opening 66f are formed at the bottom of each of the plurality of bus bar 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. The positive electrode terminal 10g and the negative electrode terminal 10h each project to the outside of the module case 60 through each opening.

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

The first connecting bus bar 71 is formed with a negative connection terminal 71a extending in the vertical direction so as to be separated from the first battery cell 11. The negative connection terminal 71a functions as a negative output terminal of the assembled battery 10. Further, the negative connection terminal 71a is electrically connected to the housing 87 via a fuse (not shown). As a result, the first connected bus bar 71 is at the ground potential.

The second connecting bus bar 72 is provided on the outer surface 62b side of the bus bar recess 84 in a manner of closing the second opening 66b. The second connecting bus bar 72 has a shape extending in the lateral direction. The portion provided in the second opening 66b of the second connected bus bar 72 is mechanically and electrically connected to each of the positive electrode terminal 10g of the first battery cell 11 and the negative electrode terminal 10h of the second battery cell 12 by laser welding or the like. Will be done. As a result, the first battery cell 11 and the second battery cell 12 are connected in series via the second connecting bus bar 72.

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

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

The fifth connecting bus bar 75 is provided on the outer surface 62b side of the bus bar recess 84 in a manner of closing the fifth opening 66e. The fifth connecting bus bar 75 has a shape extending in the height direction. The portion provided in the fifth opening 66e of the fifth connected bus bar 75 is mechanically and electrically connected to each of the positive electrode terminal 10g of the fourth battery cell 14 and the negative electrode terminal 10h of the fifth battery cell 15 by laser welding or the like. Will be done. As a result, the 4th battery cell 14 and the 5th battery cell 15 are connected in series via the 5th connecting bus bar 75.

The sixth connecting bus bar 76 is provided on the outer surface 62b side of the bus bar recess 84 in a manner of closing the sixth opening 66f. The portion of the sixth connecting bus bar 76 provided at the sixth opening 66f is mechanically and electrically connected to the positive electrode terminal 10g of the fifth battery cell 15 by laser welding or the like.

The sixth connected bus bar 76 is formed with a positive connection terminal 76a extending in the vertical direction so as to be separated from the fifth battery cell 15. The positive connection terminal 76a functions as a positive output terminal of the assembled battery 10.

As described above, as shown in FIGS. 4 and 5, the first connecting bus bar 71 and the fifth connecting bus bar 75 are located on the right wall 67d side of the lid wall 66. The second connecting bus bar 72, the fourth connecting bus bar 74, and the sixth connecting bus bar 76 are located on the central side of the lid wall 66 in the lateral direction. As a result, a space is formed between the right wall 67d side and the center side of the lid wall 66. In the following, this space is referred to as a first space.

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

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

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

<Sensor unit>
Next, the sensor unit 40 will be described with reference to FIGS. 4 and 5.

As described above, the connected bus bar 70 includes a first connected bus bar 71 to a sixth connected bus bar 76. The voltage sensor 41 has six voltage wirings 41a, one of which is electrically connected to each of the first connected bus bar 71 to the sixth connected bus bar 76 independently. The other end of each of the six voltage wirings 41a is connected to the BMU 22. As a result, the voltage detected by the six voltage wirings 41a is input to the BMU 22. The voltage wiring 41a is an insulated wire.

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

Two voltage wirings 41a connected to each of the second connected bus bar 72 and the third connected bus bar 73 are provided in the second space of the lid wall 66. One end of these two voltage wirings 41a is bolted to a portion of the corresponding connecting bus bar on the second space side. These two voltage wirings 41a extend from the corresponding connecting 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 join the four voltage wirings extending from the first space toward the first upper wall 81 at 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 wirings 42c connected to one end of the first thermistor 42a and the second thermistor 42b. The other end of each of these two temperature wirings 42c is connected to the BMU 22. As a result, 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 film.

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

In the first battery stack 10l, 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 harder 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 10 m, the second battery cell 12 is aligned with the third battery cell 13 in the height direction. As a result, the second battery cell 12 and the third battery cell 13 can easily dissipate heat.

However, the second battery cell 12 is arranged side by side with the first battery cell 11 in the horizontal direction. The fourth battery cell 14 is arranged side by side with the third battery cell 13 in the horizontal direction. Therefore, the heat of the 4th battery cell 14 is easily transferred to the 3rd battery cell 13. It is difficult for the heat of the fourth battery cell 14 to be transferred to the second battery cell 12. As a result, the temperature of the second battery cell 12 is less likely to rise than that of the third battery cell 13.

With the configuration shown above, the temperature of the fourth battery cell 14 is more likely to rise than that of the other four battery cells. The temperature of the second battery cell 12 is less likely to rise than that of 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 assembled battery 10 can be detected. By detecting the temperature of the second battery cell 12, it is expected that the lowest temperature (minimum temperature) among the plurality of battery cells constituting the assembled battery 10 can be detected.

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

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

A temperature wiring 42c connected to one end of the 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 connected to one end of 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 wirings 42c merge with the six voltage wirings at the first upper wall 81.

The submersion sensor 43 has a first counter electrode 43a and a second counter electrode 43b. The submerged sensor 43 has two submerged wirings 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 facing electrode 43a and the second facing electrode 43b are laterally separated and opposed to each other in the first space. If there is a liquid such as water containing impurities between the first counter electrode 43a and the second counter electrode 43b, both become conductive. As a result, the resistance value between the first counter electrode 43a and the second counter electrode 43b changes. This change in resistance value is input to the BMU 22 via the two submerged wires 43c.

As shown in FIG. 2, an insulating case 69 for covering the connecting bus bar 70 and the like is provided on the outer surface 62b side of the wiring case 62. 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 each of the first facing electrode 43a and the second facing electrode 43b are exposed to the outside of the insulating case 69. The other ends of the first facing electrode 43a and the second facing electrode 43b are bent so as to be separated from the wiring case 62.

The two submerged wirings 43c are provided in the first space. The two submerged wirings 43c extend from one end of the first facing electrode 43a and the second facing electrode 43b toward the first upper wall 81. The two submerged wirings 43c join the six voltage wirings and the two temperature wirings on the first upper wall 81. As a result, 10 wires are merged on the first upper wall 81. In the following, these merged wirings are referred to as sensor wirings.

The 10 sensor wirings merged at the first upper wall 81 are bundled together by the tape 85. Further, these 10 sensor wirings are fixed to the upper surface 81a of the first upper wall 81 by the binding band 86. As shown in FIGS. 4 and 5, the 10 sensor wirings extend laterally from the portion fixed by the binding band 86 to the right wall 67d side, then fold back and approach the left wall 67c side. It is extended. Therefore, the 10 sensor wirings have a U-shape on the upper surface 81a. The other ends of these 10 sensor wires are grouped by a first connector 48.

As shown in FIG. 10, the wiring board 21 is provided with a second connector 27 connected to the first connector 48. One surface of the wiring board 21 facing the height direction faces the module case 60 at a distance from the module case 60 in the height direction. The second connector 27 is mounted on the back surface 21b on the back side of this one surface. 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 side by side in the horizontal direction. As a result, the first connector 48 and the second connector 27 are arranged so as to face each other in the lateral direction.

The first connector 48 is moved laterally so as to approach the second connector 27. As a result, for example, as shown in FIG. 10, the first connector 48 is inserted into the second connector 27. The signal (state signal) detected by the sensor unit 40 can be input to the BMU 22.

<Case>
Next, the housing 87 will be described in detail. As described above, the housing 87 has a main body 89 and a connecting wall 90. The connecting wall 90 is connected to the main body 89. As a result, the housing 87 has a box shape with 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 in the height direction. The side wall 92 stands up from the edge of the inner bottom surface 91a in the height direction. The side wall 92 has a left side wall 92a and a right side wall 92b that are laterally separated and opposed to each other. Further, 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 laterally and integrally connects the left side wall 92a and the right side wall 92b. As shown in FIG. 2, the left side wall 92a has a shorter vertical length 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. For example, in FIG. 11, which schematically shows the housing 87, the left side wall 92a and the right side wall 92b are shown with the same length.

As shown in FIG. 2, the main body portion 89 has a first rib group 93a, a second rib group 93b, and a third rib group 93c arranged laterally spaced apart from each other. Each of these three rib groups has a plurality of ribs extending in the height direction from the inner bottom surface 91a. The rib has a cylindrical shape. A bolt hole is opened on the tip surface of the rib.

The first rib group 93a has four ribs. These four ribs are arranged vertically. And 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. And 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 on the inner bottom surface 91a in the lateral direction is substantially divided into two regions by the above three rib groups. That is, the region between the left side wall 92a and the right side wall 92b on the inner bottom surface 91a is the region between the first rib group 93a and the second rib group 93b, and the second rib group 93b and the third rib. It is partitioned into a region between groups 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 outwardly projecting protrusions 64n are formed on the left wall 64c of the battery case 61. Similar two protrusions 64n are formed on the right wall 64d. These two protrusions 64n are arranged so as to be separated from each other 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 the horizontal direction. A bolt hole 64o that opens in the height direction is formed in each of these four protrusions 64n.

Further, as shown in FIG. 7, the first partition wall 64e is formed with five through holes 64p that open in the height direction. 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 through hole 64p located in the middle of the five through holes 64p arranged in the vertical direction has a narrower opening area than the other four through holes 64p.

Of 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 when the battery module 1 is provided in the housing 87. The 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 the bolt holes of the four ribs of the third rib group 93c are arranged in the height direction. .. Further, 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 portion of the bolt 94 is fastened to the bolt hole 64o of the protrusion 64n and the bolt hole of the rib. Further, the shaft portion of the bolt 94 is fastened to the bolt hole of the rib in the middle of the five ribs arranged in the vertical direction through the through hole 64p. The head of the bolt 94 fastened to the bolt hole 64o and the bolt hole of the rib comes into contact with the protrusion 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 comes into contact with the inner bottom surface 91a of the bottom wall 91.

By fastening the bolts 94 shown above, the battery module 1 is fixed to the main body 89. The battery module 1 and the main body 89 can conduct heat. The battery module 1 and the main body 89 can positively transfer heat through the air between them. Note that FIG. 11 schematically showing the housing 87 shows only those of the above-mentioned plurality of ribs that contribute to the direct fixing of the battery module 1 to the main body 89. Other ribs that do not contribute to the direct fixing of the battery module 1 to the main body 89 are utilized for bolting the suppression plate and 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 the fixed wall.

As shown 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. In a state where 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-mentioned power supply bus bar 50, a first switch 31 and a second switch 32, and the like are provided. In the following, 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 side wall 92c corresponds to the facing wall.

In the region of the inner bottom surface 91a that divides a part of the arrangement space, a heat dissipation table 95 is formed so as to project on the opening side (cover side) of the housing 87 along the height direction. The heat radiating table 95 of the present embodiment has a first heat radiating table 95a and a second heat radiating table 95b arranged laterally spaced apart from each other. The first switch 31 is mounted on the first heat dissipation table 95a. The second switch 32 is mounted on the second heat dissipation table 95b. Therefore, the heat generated by the first switch 31 is thermally conducted to the first heat dissipation table 95a. The heat generated by the second switch 32 is thermally conducted to the second heat dissipation table 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. As a result, the battery pack 100 is fixed to the vehicle.

As shown in the column (a) of FIGS. 11 and 12, the surface of the end portion (end surface 89a) opposite to the connecting end with the lower side wall 92c of each of the bottom wall 91, the left side wall 92a, and the right side wall 92b. Is flush with each other in a plane facing in the vertical direction. The end face 89a provided by these three wall portions has a substantially C-shape in a plane orthogonal to the vertical direction.

Bolt holes 89b that open in the end face 89a are formed in each of the bottom wall 91, the left side wall 92a, and the right side wall 92b. Two bolt holes 89b are opened in the end faces 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, groove portions 89c for providing the sealing material 97 described later are formed on the end faces 89a of each of the bottom wall 91, the left side wall 92a, and the right side wall 92b. The groove 89c is shown by a broken line in the column (a) of FIG. The groove portion 89c is formed so as to continuously extend 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 portion 89c is located on the storage space side of the pack case 80 with respect to the opening of the bolt hole 89b. In other words, the groove portion 89c is located on the inner surface side of each of the left side wall 92a and the right side wall 92b that divides a part of the storage space of the pack case 80. The groove portion 89c is located on the inner bottom surface 91a side of the outer bottom surface 91b of the bottom wall 91.

As shown in column (b) of FIGS. 11 and 12, 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 connecting 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 lined up along two edges along the height direction of the connecting wall 90. One bolt hole 90c is located on one side 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 radiating surface 90b corresponds to the outer wall surface.

A linear sealing material 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 sealing material 97 is located on the heat transfer sheet 98 side, which will be described later, with respect to the opening of the bolt hole 90c on the heat transfer surface 90a.

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

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 has, as 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 first heat transfer sheet cell. 5 It has a heat transfer sheet cell 98e. These five heat transfer sheet cells are separated from each other 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 in order in the height direction. The second heat transfer sheet cell 98b and the third heat transfer sheet cell 98c are arranged side by side in order of height. The first heat transfer sheet cell 98a and the second heat transfer sheet cell 98b are arranged side by side so as to be laterally separated from each other. The fourth heat transfer sheet cell 98d and the third heat transfer sheet cell 98c are arranged side by side so as to be laterally separated from each other. Each of these five heat transfer sheet cells is individually adhered to the lower end surface 10f of the above five battery cells.

<Connecting the main body and the connecting wall>
As shown in FIG. 13, the connection wall 90 to the main body 89 is connected 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 complicated notation. Further, in FIGS. 13 and 15, in order to avoid complicated notation due to the overlap of the plurality of connected bus bars 70, the illustration of the connected bus bars 70 connected to each battery cell is omitted. The plurality of connected bus bars 70 are located on the arrangement space side in the storage space.

As shown in FIG. 14, in a state where 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 surface 89a side of the main body 89. Therefore, the opening window 63a formed on the bottom wall 63 is also located on the end face 89a side. Then, as shown in the column (a) of FIG. 15, the opening window 63a formed in the portion of the bottom wall 63 that partitions a part of the first stack storage space 64f is located on the right side wall 92b side. The opening window 63a formed in the portion of the bottom wall 63 that partitions a part of the second stack storage space 64g is located on the left side 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 in such a manner that the outer surface 61b of the bottom wall 63 and the end surface 89a of the main body portion 89 face each other. Due to the arrangement of the connecting wall 90 in the main body 89, the openings of the bolt holes 90c formed in the heat transfer surface 90a of the connecting wall 90 and the openings of the bolt holes 89b formed in the end surface 89a are arranged in the vertical direction. The shaft portion of the 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 comes into vertical contact with the heat dissipation surface 90b. As a result, the main body 89 and the connecting wall 90 are mechanically connected in such a manner that they approach each other in the vertical direction.

By connecting the main body portion 89 and the connecting wall 90, the heat transfer sheet 98 provided on the heat transfer surface 90a of the connecting 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 comes into contact with the lower end surface 10f of the battery cell. More specifically, each of the first heat transfer sheet cell 98a to the fifth heat transfer sheet cell 98e individually contacts the lower end surface 10f of the first battery cell 11 to the fifth battery cell 15. The contact area is the same.

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

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

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

As described above, the battery module 1 is fixed to the main body 89. The 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 connecting wall 90. According to this, the heat generated in the battery module 1 is transferred to the main body portion 89 and the connecting wall 90. As a result, deterioration of the heat dissipation performance of the battery module 1 is suppressed.

The lower side wall 92c of the main body 89 and the battery module 1 are vertically separated from each other. As a result, unlike the configuration in which the battery module is sandwiched between the lower side wall and the connecting wall, for example, in the battery pack 100, an arrangement space is formed between the lower side wall 92c and the battery module 1. A resin base 88 for accommodating the power supply bus bar 50, a fuse, a first switch 31, a second switch 32, and the like can be arranged in this arrangement space. In this way, the limitation of the arrangement of members in the pack case 80 is relaxed. Furthermore, the positive electrode terminal 10g and the negative electrode terminal 10h of the battery cell can be provided on the arrangement space side in a non-contact manner with respect to the lower side wall 92c.

The power supply bus bar 50, and the first switch 31 and the second switch 32 are provided in the arrangement space. As a result, the power supply bus bar 50 and the first switch 31 and the second switch 32 are separated from the connecting wall 90 via the battery module 1. Therefore, the heat generated by 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 connecting wall 90.

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

By suppressing the heat transfer to the connecting wall 90 as described above, it is possible to prevent the heat transfer between the connecting 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. According to this, it is suppressed that a difference in thermal resistance occurs between each of the plurality of battery cells and the connecting wall 90. Therefore, it is possible to suppress variations in the temperatures of the plurality of battery cells.

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

According to this, it is possible to prevent water droplets adhering to the battery cells due to, for example, dew condensation, from cross-linking between a plurality of battery cells via the heat transfer sheet cells. Through these water droplets, the floating charge of the battery cell is suppressed from flowing between the plurality of battery cells. Corrosion of the battery cell is suppressed due to the flow of stray charge.

By connecting the connecting wall 90 to the main body 89, the sealing material 97 is compressed in the vertical direction between the wall surface forming the groove 89c formed on the end surface 89a of the main body 89 and the heat transfer surface 90a of the connecting wall 90. To. As a result, the sealing material 97 is in close contact with the groove portion 89c and the heat transfer surface 90a, respectively, and the gap between the end surface 89a and the heat transfer surface 90a is closed.

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

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

Although the preferred embodiments of the present disclosure have been described above, the present disclosure can be variously modified and implemented without being limited to the above-described embodiments and within a range that does not deviate from the gist of the present disclosure. Is.

(First modification)
In this embodiment, for example, as shown in the column (b) of FIG. 12 and FIG. 17, the first heat transfer sheet cells 98a to the fifth heat transfer sheet cells 98e have the same physique. Therefore, an example is shown in which the contact areas of the first heat transfer sheet cells 98a to the fifth heat transfer sheet cells 98e and the contact areas of the first battery cells 11 to the fifth battery cells 15 are the same.

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

In the modification shown in FIG. 18, among the three heat transfer sheet cells adhering 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 in the vertical direction is getting bigger. Therefore, the contact area of the fourth heat transfer sheet cell 98d with respect to the fourth battery cell 14 is larger than the contact area of the other two heat transfer sheet cells with respect to the other two battery cells. As a result, the fourth battery cell 14 is more likely to conduct heat to the connecting 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 rise. However, as described above, the fourth battery cell 14 is likely to conduct heat to the connecting wall 90 via the fourth heat transfer sheet cell 98d. Therefore, it is possible to prevent variations in the temperatures of the three battery cells constituting the first battery stack 10 liters. As shown above, when there is a battery cell that easily generates heat due to the arrangement of the battery cell or the like, it is possible to adopt a configuration in which the contact area with the heat transfer sheet cell increases as the heat generation amount increases. .. As a matter 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 connecting wall 90 also increases to the same extent.

(Second modification)
In this embodiment, for example, as shown in the column (b) of FIG. 12 and FIG. 14, the heat transfer surface 90a of the connecting wall 90 has a flat shape in the direction facing in the vertical direction. However, for example, as shown in FIG. 19, the heat transfer surface 90a is locally uneven due to the formation of the inner groove portion 90d locally recessed in the direction from the heat transfer surface 90a toward the heat dissipation surface 90b. It may form a shape having. The inner groove portion 90d corresponds to the inner groove.

In the modified example shown in FIG. 19, the inner groove portion 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. An inner groove portion 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 flow to the inner groove portion 90d located between the two battery cells instead of the battery cells arranged next to each other in the height direction. This suppresses the electrical connection of the plurality of battery cells via the water droplets. The occurrence of corrosion of the battery cell due to the flow of suspended charge between the battery cells via water droplets is suppressed.

(Third modification example)
In the present embodiment, for example, as shown in FIG. 14, an example is shown in which the heat radiating surface 90b of the connecting wall 90 has a flat shape in the direction facing in the vertical direction. However, for example, as shown in FIG. 20, the heat radiating surface 90b is locally uneven due to the formation of the outer groove portion 90e locally recessed in the direction from the heat radiating surface 90b toward the heat transfer surface 90a. It may be shaped. The outer groove portion 90e corresponds to the outer groove.

In the modified example shown in FIG. 20, the same number of outer groove portions 90e as the heat transfer sheet cells are formed on the heat radiation surface 90b. The outer groove portion 90e and the heat transfer sheet cell are arranged in the vertical direction. Due to the formation of the outer groove portion 90e, the area of the heat radiating surface 90b is increased. This promotes heat dissipation through the heat transfer sheet cell of the battery module 1 and the connecting wall 90.

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

More heat dissipation fins 90f are formed in the portion of the connecting wall 90 that faces the first battery stack 10l in the vertical direction than in the portion that faces the second battery stack 10m in the connecting wall 90 in the vertical direction. This promotes heat dissipation through the connecting wall 90 of the first battery stack 10l, which is more likely to generate heat than the second battery stack 10m. It is possible to suppress temperature variation between the three battery cells of the first battery stack 10l and the two battery cells of the second battery stack 10m.

(Fifth variant)
For example, as shown in FIG. 23, when the heat transfer surface 90a side of the connecting wall 90 protrudes, it is possible to adopt a configuration in which the protruding portion is provided in the module case 60. In the case of such a configuration, the length of the connecting wall 90 in the vertical direction becomes thick. The rigidity of the connecting wall 90 is increased. Therefore, the deformation of the connecting wall 90 is suppressed by pressing the connecting wall 90 against the battery module 1 via the heat transfer sheet 98.

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

In the modified example shown in FIG. 24, a plurality of battery cells are arranged in the height direction. The upper end surface 10e of the battery cell is located on the left side wall 92a side. An opening window 63a is formed on the left wall 64c of the battery case 61. When the connecting wall 90 is connected 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 modified example shown in FIG. 24, the first side surface 10c of the fifth battery cell 15 comes into contact with the fifth heat transfer sheet cell 98e.

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

In the modified example shown in FIG. 26, a plurality of battery cells are arranged in the horizontal direction. The upper end surface 10e of the battery cell is located on the cover side. An opening window 63a is formed on 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 connecting 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 a plurality of battery cells constituting the battery stack. In the modified example 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 comes into contact with the heat transfer sheet 98. The second side surface 10d of each of the second battery cell 12 and the fourth battery cell 14 comes into contact with the heat transfer sheet 98. Needless to say, also in this modification, it is possible to adopt a configuration in which the heat transfer sheet 98 is divided into a plurality of heat transfer sheet cells.

(7th modification)
In this embodiment, an example is shown in which the assembled battery 10 has five battery cells. However, the assembled battery 10 may have two or more battery cells, and is not limited to the above example. Further, the number of battery stacks may be one or three or more.

(Other variants)
In this embodiment, an example in which a vehicle equipped with the power supply system 200 has an idle stop function is shown. However, the vehicle equipped with the power supply system 200 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 rotary electric machine 130 shown in the present embodiment replace the motor generator.

In this embodiment, an example in which the heat transfer sheet 98 comes into contact with the battery cell is shown. However, the heat transfer sheet 98 may be in contact with 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 can be adopted.

In this embodiment, an example is 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 does not have to be fixed to all three walls. For example, as shown in FIGS. 24 to 26, a configuration in which the battery module 1 is fixed only to the bottom wall 91 by bolts 94 can be adopted. Further, although not shown, it is also possible to adopt 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.

1 ... Battery module, 10e ... Upper end surface, 10g ... Positive terminal, 10h ... Negative terminal, 11 ... 1st battery cell, 12 ... 2nd battery cell, 13 ... 3rd battery cell, 14 ... 4th battery cell, 15 ... 5th battery cell, 31 ... 1st switch, 32 ... 2nd switch, 50 ... power supply bus bar, 51 ... 1st power supply bus bar, 52 ... 2nd power supply bus bar, 53 ... 3rd power supply bus bar, 54 ... 4th power supply bus bar, 60 ... module case, 61 ... battery case, 62 ... wiring case, 72 ... second connected bus bar, 73 ... third connected bus bar, 74 ... fourth connected bus bar, 75 ... fifth connected bus bar, 87 ... housing, 89 ... Main body, 90 ... connecting wall, 90a ... heat transfer surface, 90b ... heat dissipation surface, 90d ... inner groove part, 90e ... outer groove part, 90f ... heat dissipation fin, 91 ... bottom wall, 92a ... left side wall, 92b ... right side wall, 92c ... lower side wall, 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 ... 5th heat transfer sheet cell, 100 ... battery pack, 110 ... lead storage battery, 120 ... starter motor, 130 ... rotary electric machine, 140 ... engine, 150 ... electric load, 200 ... power supply system

Claims (11)

A battery module (1) in which a plurality of battery cells (11 to 15) are housed in a sensor housing (60), and
A fixed wall (91, 92a, 92b) to which the battery module is fixed, and a main body portion (89) having an facing wall (92c) that stands up from the fixed wall and faces the battery module at a distance from the fixed wall.
A connecting wall (90) connected to the main body portion in a manner of approaching the facing wall via the battery module, and a connecting wall (90).
A heat transfer sheet (98) sandwiched between the battery module and the connecting wall,
It has a power supply bus bar (50 to 54) for connecting the battery module and an external device (110, 120, 130, 140, 150) .
The power supply bus bar is a battery pack provided in an arrangement space between the battery module and the facing wall in the main body . It has switches (31, 32) connected to the power supply bus bar and controlling the connection between the battery module and the external device.
The battery pack according to claim 1 , wherein the switch is provided in the arrangement space. Electrode terminals (10 g, 10 h) are formed on the end face (10e) of the battery cell on the opposite wall side.
The battery pack according to claim 1 or 2 , wherein the battery module has a connecting bus bar (72 to 75) for connecting a plurality of electrode terminals of the battery cells in series. The battery pack according to any one of claims 1 to 3 , 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 4 , wherein each of the plurality of heat transfer sheet cells is provided on the inner wall surface (90a) of the connecting wall on the battery module side so as to be separated from each other. The battery pack according to claim 5 , wherein an inner groove (90d) is formed between the plurality of heat transfer sheet cells on the inner wall surface so as to be separated from the battery module. At least three of the battery cells are lined up in the sensor housing.
The contact area between the battery cell located inside and the heat transfer sheet cell among at least three of the three battery cells arranged side by side 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 5 or claim 6 , which is larger. The battery pack according to any one of claims 1 to 7 , wherein an outer groove (90e) is formed in an outer wall surface (90b) on the back side of the inner wall surface (90a) on the battery module side in the connecting wall. The battery pack according to any one of claims 1 to 8 , wherein the heat radiation fins (90f) are formed on the outer wall surface (90b) on the back side of the inner wall surface (90a) on the battery module side in the connecting wall. The invention according to any one of claims 1 to 9 , further comprising a sealing material (97) that seals a gap between the main body and the connecting wall by being sandwiched between the main body and the connecting wall. Battery pack. The battery pack according to any one of claims 1 to 10 , wherein the thickness of the heat transfer sheet in the direction in which the facing wall and the connecting wall are arranged via the battery module is thinner than the thickness of the connecting wall.

Images