JP2019029174A - Battery pack - Google Patents

Abstract

To provide a battery pack capable of suppressing reduction in electrical connection reliability between a bus bar and a voltage detection line.SOLUTION: A battery pack comprises: a battery module 1 that comprises a plurality of battery cells 11-15, and a first case 50 that houses the plurality of battery cells; and a coupling module 2 that has a bus bar 70 electrically and mechanically connected with positive electrode terminals 10g and negative electrode terminals 10h of the plurality of battery cells, a voltage detection line 80 electrically and mechanically connected with the bus bar, and an insulation second case 60 to which the voltage detection line is mechanically connected together with the bus bar. On a surface 60b of the second case, a part of the bus bar and a part of the voltage detection line are overlapped and contacted with each other.SELECTED DRAWING: Figure 3

Description

  The disclosure described in the present specification relates to a battery pack having a plurality of battery cells.

  As shown in Patent Document 1, a plurality of single cells, a battery case that accommodates the plurality of single cells, an insulating cover that is assembled to the battery case, and an insulating cover that overlaps with the insulating cover are provided on the anti-battery side of the insulating cover. An assembled battery module including an exhaust duct is known.

  The insulating cover is provided with a plurality of openings according to the positions of the positive terminal and the negative terminal of each unit cell. Since the insulating cover is assembled to the battery case, the terminals of the individual cells are inserted into the plurality of openings. In this state, a plurality of bus bars are attached to the insulating cover so as to close the openings.

  The exhaust duct includes a first body and a second body. The first body is provided on the battery side, and the second body is provided on the anti-battery side. A metal conductor that is electrically connected to each bus bar is insert-molded in the second body.

Japanese Patent No. 6015174

  As described above, in the assembled battery module disclosed in Patent Document 1, the insulating cover is assembled to the battery case, and the exhaust duct is provided on the side opposite to the insulating cover. A bus bar is provided in the insulating cover, and a metal conductor is insert-molded in the exhaust duct.

  Due to the above configuration, the bus bar and the metal conductor are separated from each other. In order to electrically connect the bus bar and the metal conductor in this separated state, each bus bar is integrally provided with a voltage detection terminal projecting to the anti-battery side. A part of the metal conductor (electrode side connection terminal) protrudes to the outside of the second body, and a through hole is formed there. A voltage detection terminal is inserted through the through hole. In this state, the voltage detection terminal and the electrode side connection terminal are connected by soldering or the like.

  The insulation cover and the exhaust duct individually expand and contract due to the fluctuation of the external ambient temperature. Therefore, the voltage detection terminal of the bus bar provided in the insulating cover and the electrode side connection terminal of the metal conductor insert-molded in the exhaust duct are displaced separately. As a result, stress is applied to the connection portion between the voltage detection terminal and the electrode side connection terminal. Since the voltage detection terminal is thinner than the bus bar, the rigidity is low. Therefore, the voltage detection terminal may be damaged by the stress, and the electrical connection reliability between the voltage detection terminal (bus bar) and the electrode side connection terminal (voltage detection line) may be impaired.

  Therefore, an object of the present disclosure is to provide a battery pack in which a reduction in electrical connection reliability between a bus bar and a voltage detection line is suppressed.

One of the disclosures is a battery module (1) comprising a plurality of battery cells (11-15) and a first case (50) that houses the plurality of battery cells;
A bus bar (70 to 76) electrically and mechanically connected to the electrode terminals (10g, 10h) of the plurality of battery cells, a voltage detection line (80 to 86) electrically and mechanically connected to the bus bar, and A coupling module (2) comprising an insulating second case (60) to which the voltage detection line is mechanically connected together with the bus bar,
On one surface (60b) of the second case, a part of the bus bar and a part of the voltage detection line are in contact with each other.

  As described above, in the present disclosure, the bus bars (70 to 76) and the voltage detection lines (80 to 86) are both connected to the second case (60). The bus bars (70 to 76) and the voltage detection lines (80 to 86) are in contact with each other on one surface (60b) of the second case (60). Therefore, even if the second case (60) expands and contracts due to fluctuations in the external ambient temperature, the bus bars (70 to 76) and the voltage detection lines (80 to 86) are prevented from separating. Therefore, it is suppressed that the electrical connection reliability of a bus bar (70-76) and a voltage detection line (80-86) falls.

  In addition, the code | symbol with the parenthesis is attached | subjected to the element as described in the claim as described in a claim, and each means for solving a subject. The reference numerals in parentheses are for simply indicating the correspondence with each component described in the embodiment, and do not necessarily indicate the element itself described in the embodiment. The description of the reference numerals with parentheses does not unnecessarily narrow the scope of the claims.

It is a block diagram for demonstrating a power supply system. It is a perspective view which shows schematic structure of a power supply module. FIG. 3 is an exploded perspective view of the power supply module shown in FIG. 2. It is a front view of the 1st case. It is a front view of the 2nd case. It is a front view of a power supply module. It is a front view of a power supply module. It is sectional drawing which follows the VIII-VIII line shown in FIG. It is sectional drawing which follows the IX-IX line | wire shown in FIG. It is a perspective view of the bus bar which connects between battery stacks. It is a front view which shows the modification of a power supply module. It is a front view which shows the modification of a power supply module. It is a chart for demonstrating the modification of a connection module. It is a graph for demonstrating the modification of the bus bar which connects between battery stacks.

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

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

(Overview of power supply system)
The power supply system 200 is mounted on a vehicle. The power supply system 200 includes a plurality of in-vehicle devices mounted on a vehicle and the battery pack 100. One of in-vehicle devices is a lead storage battery 110. The battery pack 100 has a lithium storage battery 10. The power supply system 200 constructs a dual power supply system with the lead storage battery 110 and the lithium storage battery 10.

  An engine 140 is another on-vehicle device. A vehicle equipped with power supply system 200 has an idle stop function of stopping engine 140 when a predetermined stop condition is satisfied and restarting engine 140 when a predetermined start condition is satisfied.

  As shown in FIG. 1, the power supply system 200 includes a starter motor 120, a rotating electrical machine 130, an electric load 150, a host ECU 160, and an MGECU 170 in addition to the lead storage battery 110 and the engine 140 described above. Each of the lead storage battery 110, the starter motor 120, and the electric load 150 is electrically connected to the battery pack 100 via the first wire harness 201. The rotating electrical machine 130 is electrically connected to the battery pack 100 via the second wire harness 202.

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

  As described above, the power supply system 200 constructs a two-power supply system that uses two of the lead storage battery 110 and the battery pack 100 (lithium storage battery 10) as power supplies.

  The electric load 150 includes 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 that may not have a constant supply power. The protective load 152 includes an in-vehicle device such as an electric shift position, an electric power steering (EPS), a brake (ABS), a door lock, a navigation system, and an in-vehicle device that is required to have a constant supply power. The protective load 152 includes in-vehicle devices that are more relevant to vehicle travel than the general load 151.

  The host ECU 160 and the MGECU 170 are one of various ECUs mounted on the vehicle. These various ECUs are electrically connected to each other via a bus wiring 161 to construct an in-vehicle network. Various ECUs perform coordinated control to control combustion of the engine 140, power generation and power running of the rotating electrical machine 130, and the like. The host ECU 160 controls the battery pack 100, and the MGECU 170 controls the rotating electrical machine 130.

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

(Outline of battery pack)
Next, the battery pack 100 will be described. As shown in FIG. 1, the battery pack 100 includes a lithium storage battery 10, a circuit board 20, and a sensor unit 40. As shown in FIG. 2, the battery pack 100 includes a first case 50 and a second case 60.

  The circuit board 20 includes a switch 22 and a BMU 23 mounted on a wiring board 21 to constitute an electric circuit. The lithium storage battery 10 and the sensor unit 40 are electrically connected to this electric circuit. This electric circuit is electrically connected to an external connection terminal indicated by a double circle in FIG. For the connection between the electric circuit and the external connection terminal, a conductive member obtained by processing a metal conductor such as a copper plate is used.

  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 through the first wire harness 201, respectively. Has been. The second external connection terminal 100 b is electrically connected to the rotating electrical machine 130 via the second wire harness 202. The third external connection terminal 100c is bolted to the vehicle body. The bolt inserted into the third external connection terminal 100c functions to connect the battery pack 100 and the vehicle body. Thereby, the battery pack 100 is body-grounded.

  As shown in FIG. 3, the lithium storage battery 10 is accommodated in the first case 50. Thereby, the battery module 1 is comprised. A bus bar 70 and a voltage detection line 80 described later are fixed to the second case 60. Thereby, the connection module 2 is configured. The battery module 1 and the connection module 2 are assembled to each other to constitute the power supply module 3. The power supply module 3 will be described in detail later.

  The battery pack 100 has a housing (not shown). This housing is produced by aluminum die casting. Each of the lithium storage battery 10, the circuit board 20, the sensor unit 40, the first case 50, and the second case 60 is accommodated in this housing.

  The housing also functions to radiate heat generated in the lithium storage battery 10 and the circuit board 20. The housing is provided below the seat of the vehicle. The third external connection terminal 100c corresponds to a hole formed in the housing. The opening of the housing is covered with a resin or metal cover. Thereby, the electric circuit and the lithium storage battery 10 are waterproofed. The arrangement of the casing (battery pack 100) is not limited to the above example. For example, the casing (battery pack 100) may be arranged in the space between the rear seat and the trunk room and in the space between the driver seat and the passenger seat.

(Electric circuit of battery pack)
Next, an electric circuit of the battery pack 100 will be described. As described above, the circuit board 20 includes the wiring board 21, the switch 22, and the BMU 23.

  The wiring board 21 is a printed board in which a wiring pattern made of a conductive material is formed on an insulating board. A first feed line 24, a second feed line 25, a third feed line 26, and a fourth feed line 27 are formed as wiring patterns on at least one of the surface and the inside of the insulating substrate.

  Terminals that are electrically connected to external connection terminals are formed on the wiring board 21. These terminals include a first internal terminal 28a, a second internal terminal 28b, a third internal terminal 28c, a fourth internal terminal 28d, and a fifth internal terminal 28e. These internal terminals are electrically connected to the external connection terminals via the conductive member.

  Specifically, the first internal terminal 28a is electrically connected to the first external connection terminal 100a. The second internal terminal 28b is electrically connected to the second external connection terminal 100b. The third internal terminal 28c is electrically connected to the third external connection terminal 100c. The fourth internal terminal 28d is electrically connected to the fourth external connection terminal 100d. The fifth internal terminal 28e is electrically connected to the fifth external connection terminal 100e.

  The first internal terminal 28 a and the second internal terminal 28 b are electrically connected via the first power supply line 24. The first power supply line 24 and the third internal terminal 28 c are electrically connected via the second power supply line 25. The first power supply line 24 and the second power supply line 25 are electrically connected via a third power supply line 26. The fourth internal terminal 28 d and the first power supply line 24 are electrically connected via the fourth power supply line 27. The first power supply line 24 and the third power supply line 26 are electrically connected through a fourth power supply line 27. The third power supply line 26 and the fifth internal terminal 28 e are electrically connected via the fourth power supply line 27.

  The switch 22 includes a first switch 29, a second switch 30, a third switch 31, a fourth switch 32, a fifth switch 33, and a sixth switch 34. Each of the first switch 29 to the fourth switch 32 includes a semiconductor switch. This semiconductor switch is specifically a MOSFET. The semiconductor switch of this embodiment is an N-channel MOSFET.

  Each of the first switch 29 to the fourth switch 32 has at least one open / close section in which two MOSFETs are connected in series. The source electrodes of the two MOSFETs are connected to each other. The gate electrodes of the two MOSFETs are electrically independent. The MOSFET has a parasitic diode. The anode electrodes of the parasitic diodes of the two MOSFETs are connected to each other.

  The first switch 29 and the second switch 30 have a plurality of opening / closing sections. The plurality of opening / closing sections are connected in parallel. The source electrodes of the plurality of opening / closing parts are electrically connected to each other.

  The third switch 31 has one opening / closing part. The fourth switch 32 has a plurality of opening / closing sections. The plurality of opening / closing sections of the fourth switch 32 are connected in series.

  In FIG. 1, only two open / close sections connected in parallel for each of the first switch 29 and the second switch 30 are shown. Only two open / close sections connected in series with the fourth switch 32 are shown. The number of opening / closing parts can be determined according to the amount of current. However, the number of opening / closing parts is not particularly limited.

  The first switch 29 is provided on the first feeder line 24. Thus, the electrical connection between the first internal terminal 28a and the second internal terminal 28b is controlled by controlling the opening and closing of the first switch 29. In other words, the electrical connection between the lead storage battery 110 and the rotating electrical machine 130 is controlled by opening / closing the first switch 29.

  The second switch 30 is provided on the second power supply line 25. Thus, the electrical connection between the third internal terminal 28c and the second internal terminal 28b is controlled by controlling the opening and closing of the second switch 30. In other words, the electrical connection between the lithium storage battery 10 and the rotating electrical machine 130 is controlled by controlling the opening and closing of the second switch 30.

  Each of the third switch 31 and the fourth switch 32 is provided in the third feeder line 26. Specifically, the third switch 31 is provided between the connection point of the third power supply line 26 with the first power supply line 24 and the connection point of the fourth power supply line 27. The fourth switch 32 is provided between the connection point of the third power supply line 26 with the fourth power supply line 27 and the connection point of the second power supply line 25.

  Thus, the electrical connection between the first internal terminal 28a and the fifth internal terminal 28e is controlled by controlling the opening and closing of the third switch 31. In other words, the electrical connection between the lead storage battery 110 and the protective load 152 is controlled by controlling the opening and closing of the third switch 31.

  Further, by controlling the opening and closing of the fourth switch 32, the electrical connection between the third internal terminal 28c and the fifth internal terminal 28e is controlled. In other words, the electrical connection between the lithium storage battery 10 and the protective load 152 is controlled by controlling the opening and closing of the fourth switch 32.

  Each of the fifth switch 33 and the sixth switch 34 is a mechanical relay. Specifically, the fifth switch 33 and the sixth switch 34 are normally closed electromagnetic relays.

  Each of the fifth switch 33 and the sixth switch 34 is provided on the fourth feeder line 27. Specifically, the fifth switch 33 is provided between the connection point of the fourth power supply line 27 with the fourth internal terminal 28 d and the connection point of the first power supply line 24. The sixth switch 34 is provided between the connection point of the fourth power supply line 27 with the first power supply line 24 and the connection point of the third power supply line 26.

  Thereby, the electrical connection between the fourth internal terminal 28d and the second internal terminal 28b is controlled by controlling the opening and closing of the fifth switch 33. In other words, the electrical connection between the lead storage battery 110 and the rotating electrical machine 130 is controlled by controlling the opening and closing of the fifth switch 33.

  Moreover, the electrical connection between the fifth internal terminal 28e and the second internal terminal 28b is controlled by controlling the opening and closing of the sixth switch 34. In other words, the electrical connection between the protective load 152 and the rotating electrical machine 130 is controlled by controlling the opening and closing of the sixth switch 34.

  As described above, the sensor unit 40 is electrically connected to the electric circuit formed by the circuit board 20. The sensor unit 40 includes sensor elements that detect the states of the lithium storage battery 10 and the switch 22. The sensor unit 40 includes 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 lithium storage battery 10. The sensor unit 40 outputs it to the BMU 23 as a state signal of the lithium storage battery 10. The sensor unit 40 detects the temperature, current, and voltage of the switch 22. The sensor unit 40 outputs it to the BMU 23 as a status signal of the switch 22.

  As shown in FIG. 2, the sensor unit 40 includes a submergence sensor 41 in addition to the temperature sensor, the current sensor, and the voltage sensor. The submergence sensor 41 has a capacitor constituted by a first counter electrode 42 and a second counter electrode 43. If there is water between the first counter electrode 42 and the second counter electrode 43, the dielectric constant (capacitance) of the capacitor changes. This capacitance is input to the BMU 23 as a status signal. The BMU 23 detects the submersion of the battery pack 100 based on whether or not the change in capacitance continues for a predetermined time.

  The BMU 23 controls the switch 22 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.

  The BMU 23 determines the state of charge (SOC) of the lithium storage battery 10 and the abnormality of the switch 22 based on the state signal of the sensor unit 40. SOC is an abbreviation for state of charge. The BMU 23 outputs a signal (determination information) that determines these SOC and abnormality to the host ECU 160.

  The host ECU 160 determines the control of the switch 22 based on the determination information input from the BMU 23 and the vehicle information input from other various ECUs. The host ECU 160 then outputs a command signal including the determined control of the switch 22 to the BMU 23. The BMU 23 controls the switch 22 based on a command signal from the host ECU 160.

  However, when the BMU 23 determines that the battery pack 100 is submerged based on the state signal of the submergence sensor 41, the BMU 23 independently determines and executes the stop of the output of the control signal to the switch 22.

(Power module)
Next, the configuration of the power supply module 3 in which the battery module 1 and the connection module 2 of the battery pack 100 are connected will be described in detail. In the following, the three directions that are orthogonal to each other are referred to as a horizontal direction, a vertical direction, and a height direction. Further, the bottom side of the casing in the height direction is indicated as the lower side, and the cover side covering the opening of the casing is indicated as the upper side. In the present embodiment, the vertical direction is along the advancing / retreating direction of the vehicle. The lateral direction is along the left-right direction of the vehicle. The height direction is along the vertical direction of the vehicle.

  As shown in FIG. 3, in the battery module 1, the lithium storage battery 10 is accommodated in the first case 50. In the connection module 2, the bus bar 70 and the voltage detection line 80 are mechanically connected to the second case 60. The battery module 1 and the connection module 2 are mechanically connected to each other by screw fastening between the first case 50 and the second case 60. The battery module 1 and the connection module 2 are electrically connected to each other by laser welding of the lithium storage battery 10 and the bus bar 70. Thereby, the power supply module 3 is configured.

(Battery module)
As shown in FIG. 3, the lithium storage battery 10 has a plurality of battery cells connected in series. The battery cell is a secondary battery. Specifically, the battery cell is a lithium ion battery. A lithium ion battery generates an electromotive voltage by a chemical reaction. A current flows through the battery cell by generating the electromotive voltage. Thereby, the battery cell generates heat. The battery cell expands.

  The battery cell is not limited to the above example, and for example, a nickel hydride secondary battery, an organic radical battery, or the like can be adopted. In this case, the name of the lithium storage battery 10 is appropriately changed according to, for example, a nickel storage battery, a radical storage battery, or the like and the type of secondary battery employed in the battery cell.

  The battery cell has a quadrangular prism shape. For this purpose, the battery cell has six sides. 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 in the lateral direction. The battery cell has an upper end surface 10e and 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 are larger in area than the other surfaces. The battery cell has a flat shape with a thin 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 are arranged apart from each other in the horizontal direction. The positive 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.

  The positive electrode terminal 10g and the negative electrode terminal 10h have a rectangular parallelepiped shape, and protrude outward from the upper end surface 10e along the vertical direction. The side surfaces of the positive electrode terminal 10g and the negative electrode terminal 10h are covered with an annular plastic body 10k that opens in the vertical direction. End faces of the positive electrode terminal 10g and the negative electrode terminal 10h facing in the vertical direction are exposed to the outside from the plastic body 10k. This end face is laser welded to the bus bar 70.

  A packing 101 as an elastic member is provided between the positive electrode terminal 10g and the negative electrode terminal 10h on the upper end surface 10e. The packing 10l has an annular shape that opens in the vertical direction. The packing 101 has a longer length in the vertical direction than the positive terminal 10g and the negative terminal 10h. As will be described later, the packing 101 is sandwiched between the battery cell and the second case 60.

  The lithium storage battery 10 of this embodiment includes a first battery cell 11, a second battery cell 12, a third battery cell 13, a fourth battery cell 14, and a fifth battery cell 15. As shown in FIG. 3, the first battery stack 11, the fourth battery cell 14, and the fifth battery cell 15 are stacked in order from the lower side to the upper side in the height direction to form the first battery stack 10 i. Yes. In the height direction, the second battery cell 12 and the third battery cell 13 are stacked in order from the lower side to the upper side to constitute the second battery stack 10j. The first battery stack 10i and the second battery stack 10j are adjacently arranged in the lateral direction.

  As shown in FIGS. 3 and 4, the first case 50 includes a first stack storage space 50a corresponding to the first battery stack 10i and a second stack storage space 50b corresponding to the second battery stack 10j. The first stack storage space 50a and the second stack storage space 50b are arranged in the horizontal direction. The first stack storage space 50a and the second stack storage space 50b are each open in the vertical direction.

  The first case 50 has a central flange portion 50c that connects the first stack storage space 50a and the second stack storage space 50b. The central flange portion 50c is located between the first stack storage space 50a and the second stack storage space 50b in the lateral direction.

  Further, the first case 50 has a first flange portion 50d that is aligned with the central flange portion 50c in the lateral direction via the first stack storage space 50a. The first case 50 has a second flange portion 50e that is aligned with the central flange portion 50c in the lateral direction via the second stack storage space 50b. The first flange portion 50d is provided on the opening side of the first stack storage space 50a on the laterally facing outer surface of the outer wall surfaces constituting the first stack storage space 50a. Similarly, the second flange portion 50e is provided on the opening side of the second stack storage space 50b on the outer side surface facing in the lateral direction of the outer wall surfaces constituting the second stack storage space 50b.

  As described above, the first case 50 has a configuration in which the first flange portion 50d, the first stack storage space 50a, the center flange portion 50c, the second stack storage space 50b, and the second flange portion 50e are sequentially arranged in the lateral direction. ing. In FIG. 4, in order to clarify the configuration, the center flange portion 50c, the first flange portion 50d, and the second flange portion 50e are shown surrounded by broken lines.

  Each of the center flange portion 50c, the first flange portion 50d, and the second flange portion 50e of the first case 50 is formed with a screw hole for screwing with the second case 60 in the vertical direction. Accordingly, screw holes are located on both sides in the lateral direction of the first stack storage space 50a. Similarly, screw holes are located on both sides in the lateral direction of the second stack storage space 50b.

  The first case 50 has a bolt fastening portion 50f for mechanically connecting the power supply module 3 to the housing. The bolt fastening portion 50f is provided on the outer surface of each of the first stack storage space 50a and the second stack storage space 50b.

  A bolt hole penetrating in the height direction is formed in the bolt fastening portion 50f. A bolt is passed through the bolt hole, and the bolt is fastened to the housing. Thereby, the power supply module 3 is fixed to the housing.

  The bolt fastening portion 50f provided on the outer surface of the first stack storage space 50a is aligned with the first flange portion 50d in the vertical direction. The bolt fastening portion 50f provided on the outer surface of the second stack storage space 50b is aligned with the second flange portion 50e in the vertical direction. More specifically, the bolt fastening portion 50f provided on the outer surface of the first stack storage space 50a is stored in the projection plane in the vertical direction of the first flange portion 50d. Similarly, the bolt fastening portion 50f provided on the outer surface of the second stack storage space 50b is stored in the vertical projection plane of the second flange portion 50e.

  As shown in FIGS. 3 and 4, the first stack storage space 50 a is partitioned into three storage spaces in order to individually store the three battery cells. The second stack storage space 50b is divided into two storage spaces in order to individually store the two battery cells.

  Specifically, the first stack storage space 50a includes a first storage space 51, a fourth storage space 54, and a fifth storage space 55 that are arranged in order from the lower side to the upper side in the height direction. The second stack storage space 50 b includes a second storage space 52 and a third storage space 53 that are arranged in order from the lower side to the upper side in the height direction.

  The first storage space 51 and the second storage space 52 are arranged in the horizontal direction via the central flange portion 50c. The third storage space 53 and the fourth storage space 54 are arranged in the horizontal direction via the central flange portion 50c. With the above storage space arrangement, a space corresponding to one storage space is formed above the fourth storage space 54. Although not shown, at least a part of the circuit board 20 is provided in this space. At least a part of the circuit board 20 is aligned with the fifth storage space 55 in the lateral direction.

  Battery cells are inserted into openings that open in the vertical direction of the five storage spaces. 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 wall constituting the storage space. 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 portions 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 on the upper end surface 10e side also protrude out of the storage space.

  Hereinafter, the arrangement of the battery cells in each storage space will be described.

  The first battery cell 11 is stored in the first storage space 51 so that the positive electrode terminal 10g is positioned on the second stack storage space 50b side. Thereby, the second main surface 10 b of the first battery cell 11 faces the fourth storage space 54.

  The second battery cell 12 is stored in the second storage space 52 so that the negative electrode terminal 10h is positioned on the first stack storage space 50a side. Thereby, the negative electrode terminal 10h of the 2nd battery cell 12 and the positive electrode terminal 10g of the 1st battery cell 11 are located in a line with the horizontal direction via the center flange part 50c. Further, the second main surface 10 b of the second battery cell 12 faces the third storage space 53.

  The third battery cell 13 is stored in the third storage space 53 so that the second main surface 10b faces the second main surface 10b of the second battery cell 12 in the height direction. Accordingly, the negative electrode terminal 10h of the third battery cell 13 and the positive electrode terminal 10g of the second battery cell 12 are arranged in the height direction. Further, the positive terminal 10g of the third battery cell 13 is located on the first stack storage space 50a side.

  The fourth battery cell 14 is stored in the fourth storage space 54 so that the second main surface 10b faces the second main surface 10b of the first battery cell 11 in the height direction. Thereby, the negative electrode terminal 10h of the 4th battery cell 14 and the positive electrode terminal 10g of the 3rd battery cell 13 are located in a line with the center flange part 50c in the horizontal direction. Further, the positive electrode terminal 10g of the fourth battery cell 14 is located on the opposite side to the second stack storage space 50b in the lateral direction. In other words, the positive terminal 10g of the fourth battery cell 14 is located on the first flange portion 50d side in the lateral direction.

  The fifth battery cell 15 is stored in the fifth storage space 55 such that the first main surface 10a faces the first main surface 10a of the fourth battery cell 14 in the height direction. Accordingly, the negative electrode terminal 10h of the fifth battery cell 15 and the positive electrode terminal 10g of the fourth battery cell 14 are arranged in the height direction.

  As described above, the positive electrode terminals 10g and the negative electrode terminals 10h are alternately arranged in the height direction in each of the first stack storage space 50a and the second stack storage space 50b.

(Linking module)
The connection module 2 includes a second case 60, a bus bar 70, and a voltage detection line 80. However, the voltage detection line 80 functions to detect the voltage of the battery cell. Therefore, the voltage detection line 80 is also one of the components of the sensor unit 40.

  As shown in FIGS. 3, 5, and 6, the second case 60 has a shape extending in the lateral direction. The center of the second case 60 is recessed in the direction away from the first case 50 in the vertical direction. The second case 60 is mechanically connected to the first case 50 so as to close the opening of the storage space of the first case 50 and cover a portion of the battery cell that has jumped out of the storage space. In this connected state, the second case 60 is accommodated in the projection plane in the vertical direction of the first case 50.

  The second case 60 is formed with five screw holes for fastening the first case 50 with screws. The screw hole penetrates the surface 60a of the second case 60 facing the first case 50 and the surface 60b on the back side thereof. The screw holes of the second case 60 correspond to the screw holes formed in the center flange portion 50c, the first flange portion 50d, and the second flange portion 50e of the first case 50, respectively. In the 2nd case 60, the screw hole is formed in the opposing flange part 60c facing the center flange part 50c in the vertical direction. Further, in the second case 60, there are screw holes in the first opposing flange portion 60d that faces the first flange portion 50d in the vertical direction and the second opposing flange portion 60e that faces the second flange portion 50e in the vertical direction. Is formed. In FIGS. 5 and 6, each of the opposing flange portion 60c, the first opposing flange portion 60d, and the second opposing flange portion 60e is surrounded by a broken line. The facing surface 60a corresponds to the back surface. The surface 60b corresponds to one surface.

  When the second case 60 is provided in the first case 50 so as to close the opening of the first case 50, the five screw holes of the second case 60 and the corresponding five screw holes of the first case 50 are vertically aligned. Line up in the direction. A case fastening member 90 as a screw member is screwed into each of the five synthetic screw holes configured by being arranged in the vertical direction. Thereby, the 1st case 50 and the 2nd case 60 are connected mechanically.

  In addition, as shown in FIG. 8 corresponding to the cross-sectional view shown by the one-dot chain line in FIG. A case nut 90b is provided at the tip protruding from the screw hole. The broken line in FIG. 8 has shown the boundary of the line in alignment with the height direction of the dashed-dotted line shown in FIG. 7, and the line in alignment with a horizontal direction. In FIG. 7, the reference numerals are omitted in order to clearly show the one-dot chain line and the two-dot chain line described later.

  In the following, a total of five synthetic screw holes constituted by the screw holes of the first case 50 and the screw holes of the second case 60 are referred to as a first screw hole 61, a second screw hole 62, a third screw hole 63, The fourth screw hole 64 and the fifth screw hole 65 are shown. In the drawing, these symbols are attached to the screw holes of the first case 50 and the second case 60, respectively.

  In the first case 50, thread grooves are formed in the first to fifth screw holes 61 to 65, respectively. However, in the second case 60, screw grooves may not be formed in each of the first screw hole 61 to the fifth screw hole 65.

  The first screw hole 61 and the second screw hole 62 are formed in the first flange portion 50d and the first opposing flange portion 60d, respectively. The first screw hole 61 and the second screw hole 62 are arranged in the height direction. The first screw holes 61 are aligned with the first storage space 51 in the lateral direction. The second screw hole 62 is aligned with the fifth storage space 55 in the lateral direction.

  The third screw hole 63 and the fourth screw hole 64 are formed in the second flange portion 50e and the second opposing flange portion 60e, respectively. The third screw hole 63 and the fourth screw hole 64 are arranged in the height direction. The third screw hole 63 is aligned with the second storage space 52 in the lateral direction. The fourth screw hole 64 is aligned with the third storage space 53 in the lateral direction.

  The fifth screw hole 65 is formed in each of the central flange portion 50c and the opposed flange portion 60c. The center position of the fifth screw hole 65 is located between the center of the first storage space 51 and the center of the fourth storage space 54 in the height direction. Similarly, the center position of the fifth screw hole 65 is located between the center of the second storage space 52 and the center of the third storage space 53 in the height direction. The fifth screw hole 65 is located between the first storage space 51 and the second storage space 52 in the lateral direction. Similarly, the fifth screw hole 65 is located between the third storage space 53 and the fourth storage space 54 in the lateral direction.

  Thus, the first stack storage space 50a is located between the first screw hole 61, the second screw hole 62, and the fifth screw hole 65. The second stack storage space 50 b is located between the third screw hole 63 and the fourth screw hole 64 and the fifth screw hole 65. In other words, the first battery stack 10 i is located between the first screw hole 61, the second screw hole 62, and the fifth screw hole 65. The second battery stack 10 j is located between the third screw hole 63 and the fourth screw hole 64 and the fifth screw hole 65. The lateral separation distance between each of the first screw hole 61 and the second screw hole 62 and the fifth screw hole 65, and the lateral distance between each of the third screw hole 63 and the fourth screw hole 64 and the fifth screw hole 65. The separation distance is equal.

  A case fastening member 90 is fastened to these five screw holes. The screw fastening seating surface of the case fastening member 90 is located on the surface 60 b of the second case 60. The case fastening member 90 is fastened to the screw hole from the second case 60 toward the first case 50 in the vertical direction.

  By the fastening of the case fastening member 90, the packing 10 l provided on the upper end surface 10 e of the battery cell is compressed in the vertical direction between the battery cell and the second case 60. Thereby, the restoring force which goes to the direction away from packing 10l along a vertical direction generate | occur | produces in packing 10l. The battery cell is pressed in the vertical direction by this restoring force. The battery cell is sandwiched between the packing 101 and a wall constituting the storage space of the first case 50. Thereby, the displacement of the vertical direction of a battery cell is suppressed. The expansion of the battery cell in the vertical direction is also suppressed. The packing 101 may not be provided. A configuration in which the battery cell and the second case 60 are in direct contact may be employed.

  The second case 60 is formed with a plurality of openings for electrically connecting the first battery cell 11 to the fifth battery cell 15 and the bus bar 70. The plurality of openings penetrates the opposing surface 60a and the surface 60b along the vertical direction. The opening is formed corresponding to each of the positive terminal 10g and the negative terminal 10h that functions as an electrical series connection of a plurality of battery cells and an output.

  In the second case 60, a first opening 66a, a second opening 66b, a third opening 66c, a fourth opening 66d, a fifth opening 66e, and a sixth opening 66f are formed as openings. ing. The first opening 66a is formed at a portion of the second case 60 that faces the negative electrode terminal 10h of the first battery cell 11 in the vertical direction when the second case 60 is connected to the first case 50. The second opening 66b is formed in a portion of the second case 60 that faces the positive electrode terminal 10g of the first battery cell 11 in the vertical direction and a portion that faces the negative electrode terminal 10h of the second battery cell 12 in the vertical direction. ing.

  The third opening 66c is formed in a portion of the second case 60 facing the positive electrode terminal 10g of the second battery cell 12 in the vertical direction and a portion facing the negative electrode terminal 10h of the third battery cell 13 in the vertical direction. ing. The fourth opening 66d is formed in a portion of the second case 60 that faces the positive electrode terminal 10g of the third battery cell 13 in the vertical direction and a portion that faces the negative electrode terminal 10h of the fourth battery cell 14 in the vertical direction. ing.

  The fifth opening 66e is formed in a portion of the second case 60 facing the positive electrode terminal 10g of the fourth battery cell 14 in the vertical direction and a portion facing the negative electrode terminal 10h of the fifth battery cell 15 in the vertical direction. ing. The sixth opening 66f is formed in a portion of the second case 60 that faces the positive electrode terminal 10g of the fifth battery cell 15 in the vertical direction.

  The connection module 2 includes a first bus bar 71, a second bus bar 72, a third bus bar 73, a fourth bus bar 74, a fifth bus bar 75, and a sixth bus bar 76 as the bus bar 70. The first bus bar 71 to the sixth bus bar 76 are provided on the surface 60 b of the second case 60. A part thereof is provided in the corresponding opening.

  The first bus bar 71 is mechanically connected to the surface 60b side of the second case 60 so as to close the first opening 66a. A portion of the first 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 bus bar 71 is formed with a minus connection terminal 71a protruding in the direction from the facing surface 60a to the surface 60b in the vertical direction. The minus connection terminal 71 a functions as a minus output terminal of the battery pack 100. The first bus bar 71 is connected to the ground potential.

  The second bus bar 72 is mechanically connected to the surface 60b side of the second case 60 so as to close the second opening 66b. The second bus bar 72 has a shape extending in the lateral direction. The part provided in the second opening 66b in the second bus bar 72 is mechanically and electrically connected to the positive terminal 10g of the first battery cell 11 and the negative terminal 10h of the second battery cell 12 by laser welding or the like. The Thus, the first battery cell 11 and the second battery cell 12 are connected in series via the second bus bar 72.

  The third bus bar 73 is mechanically connected to the surface 60b side of the second case 60 so as to close the third opening 66c. The third bus bar 73 has a shape extending in the height direction. The part provided in the third opening 66c of the third bus bar 73 is mechanically and electrically connected to the positive terminal 10g of the second battery cell 12 and the negative terminal 10h of the third battery cell 13 by laser welding or the like. The Accordingly, the second battery cell 12 and the third battery cell 13 are connected in series via the third bus bar 73.

  The fourth bus bar 74 is mechanically connected to the surface 60b side of the second case 60 so as to close the fourth opening 66d. The fourth bus bar 74 has a shape extending in the lateral direction. The part provided in the fourth opening 66d of the fourth bus bar 74 is mechanically and electrically connected to the positive terminal 10g of the third battery cell 13 and the negative terminal 10h of the fourth battery cell 14 by laser welding or the like. The As a result, the third battery cell 13 and the fourth battery cell 14 are connected in series via the fourth bus bar 74.

  The fifth bus bar 75 is mechanically connected to the surface 60b side of the second case 60 so as to close the fifth opening 66e. The fifth bus bar 75 has a shape extending in the height direction. The part provided in the fifth opening 66e in the fifth bus bar 75 is mechanically and electrically connected to the positive terminal 10g of the fourth battery cell 14 and the negative terminal 10h of the fifth battery cell 15 by laser welding or the like. The As a result, the fourth battery cell 14 and the fifth battery cell 15 are connected in series via the fifth bus bar 75.

  The sixth bus bar 76 is mechanically connected to the surface 60b side of the second case 60 so as to close the sixth opening 66f. The part provided in the sixth opening 66f of the sixth bus bar 76 is mechanically and electrically connected to the positive terminal 10g of the fifth battery cell 15 by laser welding or the like. The sixth bus bar 76 is formed with a positive connection terminal 76a protruding in the direction from the facing surface 60a to the surface 60b in the vertical direction. The plus connection terminal 76 a functions as a plus output terminal of the battery pack 100.

  As described above, the second bus bar 72 to the fifth bus bar 75 serve to connect two battery cells in series. Of these four bus bars, the fifth bus bar 75 functions to connect the fourth battery cell 14 and the fifth battery cell 15 constituting the first battery stack 10i in series. The third bus bar 73 functions to connect the second battery cell 12 and the third battery cell 13 constituting the second battery stack 10j in series. Therefore, each of the fifth bus bar 75 and the third bus bar 73 has a shape extending in the height direction in which the battery cells are stacked.

  On the other hand, the second bus bar 72 functions to connect the first battery cell 11 of the first battery stack 10i and the second battery cell 12 of the second battery stack 10j in series. The fourth bus bar 74 functions to connect the third battery cell 13 of the second battery stack 10j and the fourth battery cell 14 of the first battery stack 10i in series. Therefore, each of the second bus bar 72 and the fourth bus bar 74 has a shape extending in the lateral direction in which the first battery stack 10i and the second battery stack 10j are arranged. The second bus bar 72 and the fourth bus bar 74 are larger in size than the third bus bar 73 and the fifth bus bar 75, respectively.

  As shown in FIGS. 3 and 5, the second opening 66b closed by the second bus bar 72 is formed with two openings arranged side by side across the opposing flange 60c. Similarly, the fourth opening 66d closed by the fourth bus bar 74 is formed with two openings arranged side by side across the opposing flange portion 60c.

  Depending on the shape and arrangement of the second opening 66b and the fourth opening 66d, each of the second bus bar 72 and the fourth bus bar 74 has a configuration shown in FIG. The second bus bar 72 has a first end 72a electrically connected to the positive terminal 10g of the first battery cell 11, a second end 72b electrically connected to the negative terminal 10h of the second battery cell 12, and The central portion 72c relays the first end portion 72a and the second end portion 72b.

  The boundary between the first end portion 72a and the central portion 72c is bent. The boundary between the second end portion 72b and the central portion 72c is also bent. The bending of the boundary between the first end portion 72a and the central portion 72c and the bending of the boundary between the second end portion 72b and the central portion 72c are in the same direction in the vertical direction. The boundary between the first end portion 72a and the central portion 72c, and the second end portion 72a and the second end portion 72b are positioned closer to the facing surface 60a of the second case 60 than the central portion 72c. Each boundary between the end portion 72b and the central portion 72c is bent.

  The fourth bus bar 74 has a first end 74a electrically connected to the positive terminal 10g of the third battery cell 13, a second end 74b electrically connected to the negative terminal 10h of the fourth battery cell 14, and The central portion 74c relays the first end portion 74a and the second end portion 74b.

  The boundary between the first end portion 74a and the central portion 74c is bent. The boundary between the second end portion 74b and the central portion 74c is also bent. The bending of the boundary between the first end portion 74a and the central portion 74c and the bending of the boundary between the second end portion 74b and the central portion 74c are in the same direction in the vertical direction. The boundary between the first end portion 74a and the central portion 74c, and the second end portion so that each of the first end portion 74a and the second end portion 74b is located closer to the facing surface 60a side of the second case 60 than the central portion 74c. Each boundary between the end 74b and the center 74c is bent.

  Each of the central portion 72 c of the second bus bar 72 and the central portion 74 c of the fourth bus bar 74 is provided on the opposing flange portion 60 c of the second case 60. In these central portions, a lightening portion corresponding to the fifth screw hole 65 is formed. The upper end portion of the central portion 72c of the second bus bar 72 is partially cut out in a semicircular shape to form a lightening portion 72d. The lower end portion of the central portion 74c of the fourth bus bar 74 is partly cut out in a semicircular shape, thereby forming a thinned portion 74d. The thinned portion 72d and the thinned portion 74d are arranged in the height direction. As a result, a substantially circular space corresponding to the fifth screw hole 65 is formed by the two thinned portions.

  The opposing flange portion 60c of the second case 60 is formed with a protrusion 67 corresponding to the shape of the above-described two lightening portions. The protrusion 67 has a cylindrical shape. The protrusion 67 protrudes in the direction from the facing surface 60a toward the surface 60b in the vertical direction. The outer diameter of the projection 67 is substantially the same as the diameter of the substantially circular space formed by the two hollow portions.

  The fifth screw hole 65 is formed in a portion surrounded by the protrusion 67 on the surface 60 b of the second case 60. The protrusion 67 is formed at the edge of the opening on the surface 60 b side of the fifth screw hole 65. For this reason, when the case fastening member 90 is inserted into the fifth screw hole 65, the protrusion 67 is positioned between the case fastening member 90 and each of the second bus bar 72 and the fourth bus bar 74.

  By the way, a part of the central portion 72c of the second bus bar 72 is locally thinned by the formation of the above-described thinned portion 72d. However, the shortest length of the lateral width (length in the height direction) orthogonal to the extending direction of the central portion 72c is more than half of the lateral width of the central portion 72c. Similarly, the shortest length of the lateral width (length in the height direction) orthogonal to the extending direction of the central portion 74c of the fourth bus bar 74 is more than half of the lateral width of the central portion 74c. The shortest length is about the horizontal width (the length in the horizontal direction) orthogonal to the extending direction of the third bus bar 73 and the fifth bus bar 75. Therefore, the resistance per unit length in the extending direction of the shortest portion of each of the central portion 72c of the second bus bar 72 and the central portion 74c of the fourth bus bar 74 is a unit in the extending direction of each of the third bus bar 73 and the fifth bus bar 75. It is about the same as the resistance per length.

  As described above, the positive electrode terminal 10g and the negative electrode terminal 10h of the battery cell are separated in the lateral direction. Separate bus bars are connected to the positive electrode terminal 10g and the negative electrode terminal 10h of one battery cell. Therefore, a space is formed in a portion of the upper end surface 10e of the battery cell in the second case 60 that faces the portion between the positive electrode terminal 10g and the negative electrode terminal 10h. That is, a space is formed between a plurality of openings provided in the second case 60 where the bus bar 70 is provided.

  On the first battery stack 10i side in the second case 60, there is a space between the first opening 66a and the fifth opening 66e and the second opening 66b, the fourth opening 66d, and the sixth opening 66f. Is configured. On the second battery stack 10j side in the second case 60, an empty space is formed between the second opening 66b, the fourth opening 66d, and the third opening 66c. A voltage detection line 80 is provided in these empty spaces.

  In the following, the part located in the empty space on the first battery stack 10i side in the second case 60 is referred to as a first empty part 60f. The part located in the empty space on the second battery stack 10j side in the second case 60 is indicated as a second empty part 60g. In FIGS. 5 and 6, the first empty part 60f and the second empty part 60g are shown surrounded by a one-dot chain line.

  The voltage detection line 80 is an insulated wire formed by covering a conductive wire with an insulator. A terminal 80 a for electrically connecting to the bus bar 70 is connected to one end of the voltage detection line 80. The terminal 80a has a through hole penetrating in the vertical direction. The other ends of the plurality of voltage detection lines 80 are grouped together in a connector 80b. The connector 80b is connected to the connector of the circuit board 20 located above the fourth storage space 54. In the drawing, the connector 80b is located above the first battery stack 10i, but the connector 80b may be located above the second battery stack 10j where the circuit board 20 is located. The position of the connector 80b can be set as appropriate as long as the wiring length of the plurality of wirings combined in the connector 80b allows.

  The connection module 2 uses the first voltage detection line 81, the second voltage detection line 82, the third voltage detection line 83, the fourth voltage detection line 84, the fifth voltage detection line 85, and the sixth voltage as the voltage detection line 80. A detection line 86 is provided.

  The first voltage detection line 81 functions to detect the potential (ground potential) of the negative electrode terminal 10 h of the first battery cell 11. The second voltage detection line 82 functions to detect a potential between the first battery cell 11 and the second battery cell 12. The third voltage detection line 83 functions to detect the potential between the second battery cell 12 and the third battery cell 13.

  The fourth voltage detection line 84 functions to detect the potential between the third battery cell 13 and the fourth battery cell 14. The fifth voltage detection line 85 functions to detect the potential between the fourth battery cell 14 and the fifth battery cell 15. The sixth voltage detection line 86 functions to detect the potential (maximum potential) of the positive electrode terminal 10g of the fifth battery cell 15.

  As shown in FIGS. 3 and 6, the bus bar 70 is formed with a connecting terminal 70 a for connecting to the terminal 80 a of the voltage detection line 80. A through hole penetrating in the vertical direction is formed in the connecting terminal 70a. These connection terminals 70a are provided on the surface 60b of the first empty part 60f or the second empty part 60g.

  As shown in FIG. 6, in the 1st bus-bar 71, the connection terminal 70a is formed in the 1st empty part 60f side. In the second bus bar 72, a connection terminal 70a is formed on the second empty portion 60g side of the second end 72b. In the third bus bar 73, a connection terminal 70a is formed on the second empty portion 60g side.

  Similarly, in the fourth bus bar 74, a connection terminal 70a is formed on the first empty portion 60f side of the second end portion 74b. In the fifth bus bar 75, a connecting terminal 70a is formed on the first empty portion 60f side. In the sixth bus bar 76, a connection terminal 70a is formed on the first empty portion 60f side.

  The connection terminals 70a of the first bus bar 71, the fourth bus bar 74, the fifth bus bar 75, and the sixth bus bar 76 are provided on the surface 60b of the first empty portion 60f. The connection terminals 70a of the remaining second bus bar 72 and third bus bar 73 are provided on the surface 60b of the second empty portion 60g.

  The arrangement of the connecting terminals is not limited to the above example. For example, in the 2nd bus bar 72, the connection terminal 70a may be formed in the 1st empty part 60f side in the 1st end part 72a. In the 4th bus bar 74, the connection terminal 70a may be formed in the 2nd empty part 60g side in the 1st end part 74a. In this case, the connection terminal 70a of the second bus bar 72 is provided on the surface 60b of the first empty portion 60f. The connection terminal 70a of the fourth bus bar 74 is provided on the surface 60b of the second empty portion 60g. The arrangement of the connecting terminals is determined according to the empty areas of the first empty part 60f and the second empty part 60g, the arrangement of the voltage detection lines 80, the sensor elements provided in the empty parts, and the like.

  A screw hole for fixing the voltage detection line 80 together with the bus bar 70 is formed in each of the first empty part 60f and the second empty part 60g of the second case 60. The screw hole is open to the surface 60b, and is formed along the vertical direction from the surface 60b toward the facing surface 60a. This screw hole is non-penetrating.

  The screw holes include a first screw hole 68a, a second screw hole 68b, a third screw hole 68c, a fourth screw hole 68d, a fifth screw hole 68e, and a sixth screw hole 68f. Of these six screw holes, four of the first screw hole 68a, the fourth screw hole 68d, the fifth screw hole 68e, and the sixth screw hole 68f are formed in the first empty portion 60f. The remaining two second screw holes 68b and third screw holes 68c are formed in the second empty portion 60g.

  The terminal 80a of the voltage detection line 80 is screw-fastened by the element fastening member 91 together with the connection terminal 70a of the bus bar 70 corresponding to these screw holes. That is, the connection terminal 70 a of the first bus bar 71 and the terminal 80 a of the first voltage detection line 81 are screwed to the first screw hole 68 a by the element fastening member 91. The connection terminal 70 a of the second bus bar 72 and the terminal 80 a of the second voltage detection line 82 are screwed to the second screw hole 68 b by the element fastening member 91. The connection terminal 70 a of the third bus bar 73 and the terminal 80 a of the third voltage detection line 83 are screw-fastened to the third screw hole 68 c by the element fastening member 91.

  The connection terminal 70a of the fourth bus bar 74 and the terminal 80a of the fourth voltage detection line 84 are screwed to the fourth screw hole 68d by the element fastening member 91. The connection terminal 70a of the fifth bus bar 75 and the terminal 80a of the fifth voltage detection line 85 are screwed to the fifth screw hole 68e by the element fastening member 91. The connection terminal 70a of the sixth bus bar 76 and the terminal 80a of the sixth voltage detection line 86 are screw-fastened to the sixth screw hole 68f by the element fastening member 91.

  The element fastening member 91 has a washer and a shaft portion extending from the washer. As shown in FIGS. 3 and 9, the terminal 80 a and the connection terminal 70 a are inserted into the element fastening member 91 in such a manner that the terminal 80 a and the connection terminal 70 a are arranged in order from the washer side toward the tip of the shaft portion. Thereby, the terminal 80a and the connection terminal 70a overlap in the axial direction (vertical direction) of the element fastening member 91. In this state, the nut 92 is screwed from the tip of the shaft portion of the element fastening member 91. As a result, the terminal 80 a and the connecting terminal 70 a are sandwiched between the washer of the element fastening member 91 and the nut 92. As a result, the terminal 80a and the connecting terminal 70a overlap each other and come into contact with each other. The element fastening member 91 is screwed into the screw hole in a state where the terminal 80a and the connecting terminal 70a are held in contact with each other. Thereby, the terminal 80a of the voltage detection line 80 and the connection terminal 70a of the bus bar 70 are in contact with each other on the surface 60b of the second case 60. The element fastening member 91 and the nut 92 correspond to the fastening member. A washer may be used instead of the nut 92. Further, the nut 92 and the washer may not be provided. In addition, the broken line in FIG. 9 has shown the boundary of the line in alignment with the height direction of the dashed-two dotted line shown in FIG. 7, and the line in alignment with a horizontal direction.

  As described above, the bus bar 70 and the voltage detection line 80 are mechanically connected to the second case 60 while the bus bar 70 and the voltage detection line 80 are electrically connected to each other on the surface 60 b of the second case 60. With the bus bar 70 and the voltage detection line 80 fixed to the second case 60 in this manner, the bus bar 70 and the battery cell are laser-welded. As shown in FIG. 3, the bus bar 70 is formed with a minute hole 70b. A laser is irradiated around the minute hole 70b from the bus bar toward the electrode terminal. By doing so, the bus bar 70 and the electrode terminal are electrically and mechanically connected. The connection between the bus bar 70 and the electrode terminal may be made after the first case 50 and the second case 60 are mechanically connected by the case fastening member 90 or before that.

  In order to reduce the connection resistance between the bus bar 70 and the voltage detection line 80, the connection terminal 70a and the terminal 80a are connected by soldering after the connection terminal 70a and the terminal 80a are sandwiched between the element fastening member 91 and the nut 92. May be.

  As shown in FIGS. 3 and 5, a plurality of first individual grooves 69a in which the first voltage detection line 81 to the sixth voltage detection line 86 are individually provided in the first empty part 60f and the second empty part 60g, respectively. A sixth individual groove 69f is formed. These individual grooves are formed such that the surface 60b of the second case 60 is locally recessed toward the facing surface 60a in the vertical direction. Each of the first screw hole 68a to the sixth screw hole 68f is formed on the bottom wall of the side wall and the bottom wall forming the first individual groove 69a to the sixth individual groove 69f. Accordingly, the terminals 80a of the first voltage detection line 81 to the sixth voltage detection line 86 are surrounded by the side walls of the individual grooves.

  Further, a common groove communicating with a plurality of individual grooves is formed in each of the first empty part 60f and the second empty part 60g. The common groove is formed such that the surface 60b of the second case 60 is locally recessed toward the facing surface 60a in the vertical direction.

  A first common groove 69g communicating with each of the first individual groove 69a, the fourth individual groove 69d, the fifth individual groove 69e, and the sixth individual groove 69f is formed in the first empty portion 60f. A second common groove 69h that communicates with the second individual groove 69b and the third individual groove 69c is formed in the second empty portion 60g.

  In the first common groove 69g, a part of the central portion of each of the first voltage detection line 81, the fourth voltage detection line 84, the fifth voltage detection line 85, and the sixth voltage detection line 86 is bundled. In the second common groove 69h, a part of the central portion of each of the second voltage detection line 82 and the third voltage detection line 83 is provided in a bundle.

  As shown in FIG. 6, a submergence sensor 41 is provided in the first empty part 60f. A first electrode groove 69 i corresponding to the first counter electrode 42 of the submergence sensor 41 and a second electrode groove 69 j corresponding to the second counter electrode 43 are formed in the first empty portion 60 f. Each of the first electrode groove 69i and the second electrode groove 69j is formed such that the surface 60b of the second case 60 is locally recessed toward the facing surface 60a in the vertical direction.

  The first counter electrode 42 is mechanically fixed to the bottom wall of the first electrode groove 69i with a screw. Similarly, the second counter electrode 43 is mechanically fixed to the bottom wall of the second electrode groove 69j with a screw. A side wall is located between the first counter electrode 42 and the second counter electrode 43, and fluctuations in the distance between them are suppressed.

  The first electrode groove 69i and the second electrode groove 69j are also communicated with the first common groove 69g together with the first individual groove 69a, the fourth individual groove 69d, the fifth individual groove 69e, and the sixth individual groove 69f. An insulated wire is connected to each of the first counter electrode 42 and the second counter electrode 43. The central portion of the insulated wire is also provided in the first common groove 69g together with the first voltage detection line 81, the fourth voltage detection line 84, the fifth voltage detection line 85, and the sixth voltage detection line 86. This insulated wire is also bundled together with the first voltage detection line 81, the fourth voltage detection line 84, the fifth voltage detection line 85, and the sixth voltage detection line 86 in the first common groove 69g. Further, the other end of the insulated wire is also integrated into the connector 80 b in the same manner as the other end of the voltage detection line 80.

  Although not shown, a temperature sensor such as a thermistor included in the sensor unit 40 can also be provided in the first empty part 60f and the second empty part 60g. In this way, by consolidating the wiring and sensor elements in the first empty part 60f and the second empty part 60g, it is possible to fit the second case 60 in the projection plane in the vertical direction of the first case 50. .

(Function and effect)
Next, the function and effect of the battery pack 100 according to the present embodiment will be described.

(About connected modules)
As described above, the bus bar 70 and the voltage detection line 80 are mechanically connected to the second case 60 while the bus bar 70 and the voltage detection line 80 are electrically connected to each other. The connection terminal 70a of the bus bar 70 and the terminal 80a of the voltage detection line 80 overlap each other on the surface 60b of the second case 60 and are in contact with each other.

  Therefore, even if the second case 60 expands and contracts due to a change in the external ambient temperature, the bus bar 70 and the voltage detection line 80 are prevented from separating. Therefore, it is possible to suppress a decrease in electrical connection reliability between the bus bar 70 and the voltage detection line 80.

  The connection terminal 70 a of the bus bar 70 and the terminal 80 a of the voltage detection line 80 are inserted into the shaft portion of the element fastening member 91 and are sandwiched between the washer of the element fastening member 91 and the nut 92. The element fastening member 91 opens to the surface 60b of the second case 60, and is screwed into a non-penetrating screw hole formed from the surface 60b toward the facing surface 60a.

  According to this, the bus bar 70 and the voltage detection line 80 are pressed against the second case 60 by the element fastening member 91 from the surface 60b toward the facing surface 60a. Therefore, even if the bus bar 70 and the voltage detection line 80 are pressed from the facing surface 60a toward the surface 60b due to the expansion of the battery cell, the contact between the bus bar 70 and the voltage detection line 80 is caused by the element fastening member 91 and the nut 92. Retained. As a result, the electrical connection between the bus bar 70 and the voltage detection line 80 is suppressed from becoming unstable. For example, compared with the structure which has the 1st connection member which electrically connects a bus-bar and a voltage detection line, and the 2nd connection member which mechanically connects a bus-bar and a voltage detection line to a 2nd case. An increase in the number of parts is suppressed.

  In the second case 60, a plurality of first individual grooves 69a to sixth individual grooves 69f in which the first voltage detection lines 81 to the sixth voltage detection lines 86 are individually provided are formed. The terminals 80a of the first voltage detection line 81 to the sixth voltage detection line 86 are surrounded by the side walls of the individual grooves. According to this, the swing of the voltage detection line 80 is suppressed. Therefore, the electrical connection between the voltage detection line 80 and the bus bar 70 is suppressed from becoming unstable.

  The voltage detection line 80 is an insulated wire. The second case 60 includes a first common groove 69g that communicates with the first individual groove 69a, the fourth individual groove 69d, the fifth individual groove 69e, and the sixth individual groove 69f, and a second individual groove 69b. A second common groove 69h communicated with each of the third individual grooves 69c is formed.

  Accordingly, the first voltage detection line 81, the fourth voltage detection line 84, the fifth voltage detection line 85, and the sixth voltage detection line 86 can be brought into contact with each other and bundled in the first common groove 69g. The second voltage detection line 82 and the third voltage detection line 83 can be brought into contact with each other and bundled in the second common groove 69h.

  The positive electrode terminal 10g and the negative electrode terminal 10h of the battery cell are separated in the lateral direction. The voltage detection line 80 is provided in each of the first empty part 60f and the second empty part 60g of the second case 60 configured for this purpose. According to this, the increase in the physique of the 2nd case 60 is suppressed compared with the structure by which a voltage detection line is provided outside an empty part.

  The second case 60 is housed in the projection plane in the vertical direction of the first case 50 by consolidating the wiring and sensor elements in the first empty portion 60f and the second empty portion 60g. Thereby, the increase in the physique of the battery pack 100 is suppressed.

  After the bus bar 70 and the voltage detection line 80 are electrically connected by the element fastening member 91, the bus bar 70 and the electrode terminal of the battery cell are laser-welded. According to this, for example, unlike the manufacturing method in which the bus bar and the voltage detection line are electrically connected after laser welding of the bus bar and the electrode terminal of the battery cell, the bus bar and the voltage detection line are electrically connected. Stress is not applied to the connection portion between the bus bar and the battery cell. As a result, the electrical connection reliability between the bus bar 70 and the battery cell is suppressed from decreasing.

  As shown in FIG. 9, the packing 101 and the element fastening member 91 are not aligned in the vertical direction. Thus, unlike the configuration in which the packing and the element fastening member are arranged in the vertical direction, an increase in the vertical size of the connection module 2 is suppressed.

(About bus bar)
A hollow portion corresponding to the fifth screw hole 65 is formed at the center of each of the second bus bar 72 and the fourth bus bar 74 that electrically connect the first battery stack 10i and the second battery stack 10j. The first battery stack 10 i is located between the first screw hole 61 and the second screw hole 62 and the fifth screw hole 65. The second battery stack 10 j is located between the third screw hole 63 and the fourth screw hole 64 and the fifth screw hole 65.

  Thus, screw holes are located on both sides of each battery stack in the lateral direction. According to this, even if the number of battery stacks is increased, the separation distance of the case fastening member 90 screwed into the screw hole is suppressed. In the case of this embodiment, the case fastening member 90 screwed to the screw hole can be made into one battery cell. Thereby, expansion of a battery cell can be suppressed effectively. As a result, it is suppressed that the electrical connection reliability between the battery cell and the bus bar 70 is lowered.

  The case fastening member 90 is provided within the height of the battery stack. Thereby, it is suppressed that the physique of the battery pack 100 becomes long in the height direction.

  The lateral separation distance between each of the first screw hole 61 and the second screw hole 62 and the fifth screw hole 65, and the lateral distance between each of the third screw hole 63 and the fourth screw hole 64 and the fifth screw hole 65. The separation distance is equal. According to this, it is suppressed that a difference arises between expansion suppression of the battery cell which comprises the 1st battery stack 10i by the case fastening member 90, and expansion suppression of the battery cell which comprises the 2nd battery stack 10j.

  There is a possibility that the vertical positions of the two battery cells to be connected are shifted due to manufacturing variations. When the bus bar 70 is joined to each of the one positive electrode terminal 10g and the other negative electrode terminal 10h in a state where the positional deviation between the two battery cells occurs in this way, the bus bar 70 is used to bring the electrode terminal and the bus bar 70 into contact with each other. It must be elastically deformed in the vertical direction. When the joining of each of the positive terminal 10g and the negative terminal 10h and the bus bar 70 is completed, the elastic deformation of the bus bar 70 is released. With this release, the bus bar 70 tries to return to its original shape. At this time, the restoring force of the bus bar 70 is applied to the joint portion between each of the positive terminal 10 g and the negative terminal 10 h and the end of the bus bar 70.

  Moreover, although each battery cell expand | swells by aged deterioration, the increase in the volume by the expansion | swelling is not uniform. The stress is applied to the joint portion between each of the positive electrode terminal 10 g and the negative electrode terminal 10 h and the end portion of the bus bar 70 depending on the difference in the degree of expansion of each battery cell.

  On the other hand, the second bus bar 72 has a first end 72a connected to the positive terminal 10g of the first battery cell 11, a second end 72b connected to the negative terminal 10h of the second battery cell 12, and It has a central portion 72c that relays the first end 72a and the second end 72b. Each of the boundary between the first end portion 72a and the central portion 72c and the boundary between the second end portion 72b and the central portion 72c are bent.

  Similarly, the fourth bus bar 74 has a first end 74a connected to the positive terminal 10g of the third battery cell 13, a second end 74b connected to the negative terminal 10h of the fourth battery cell 14, and the first A central portion 74c that relays the end portion 74a and the second end portion 74b is provided. Each of the boundary between the first end portion 74a and the central portion 74c and the boundary between the second end portion 74b and the central portion 74c are bent.

  Thereby, the elastic deformation of each of the first end portion 72a and the second end portion 72b and the central portion 72c hardly affects the other of the first end portion 72a and the second end portion 72b. Similarly, elastic deformation of one of the first end portion 74a and the second end portion 74b and the central portion 74c is less likely to affect the other of the first end portion 74a and the second end portion 74b. Yes.

  Further, a thinned portion 72d is formed in the central portion 72c, and a thinned portion 74d is formed in the central portion 74c. Therefore, the central part is easily elastically deformed. Therefore, it is suppressed that the elastic deformation of a center part affects the junction part of an edge part and an electrode terminal.

  As described above, stress is suppressed from being applied to the joint portion between the electrode terminal and the end of the bus bar 70. As a result, it is suppressed that the electrical connection reliability between the battery cell and the bus bar 70 is lowered.

  The shortest lateral width of the central portion 72c perpendicular to the extending direction of the portion where the thinned portion 72d is formed is at least half the lateral width of the portion where the thinned portion 72d is not formed in the central portion 72c. The shortest lateral width of the central portion 74c perpendicular to the extending direction of the portion where the thinned portion 74d is formed is at least half the lateral width of the portion where the thinned portion 74d is not formed in the central portion 74c.

  According to this, it is suppressed that the resistance of the bus bar becomes extremely high due to the formation of the thinned portion.

  The upper end portion of the central portion 72c of the second bus bar 72 is partially cut out in a semicircular shape to form a thinned portion 72d, and the lower end portion of the central portion 74c of the fourth bus bar 74 is formed in a semicircular shape. The cutout portion 74d is formed by cutting out the portion. The thinned portion 72d and the thinned portion 74d are arranged in the height direction to form a substantially circular space.

  One protruding portion 67 corresponding to the two lightening portions is formed on the opposing flange portion 60c of the second case 60. And the 5th screw hole 65 is formed in the site | part enclosed by the projection part 67 in the surface 60b of the 2nd case 60. As shown in FIG.

  According to this, unlike the configuration in which one screw hole is formed in the second case with respect to the lightening portion of one bus bar, an increase in the resistance of the bus bar can be suppressed. Therefore, an increase in current loss is suppressed.

  Further, since the protruding portion 67 serves as a guide, it is easy to dispose the bus bar in which the thinned portion is formed in the second case 60.

  A fifth screw hole 65 is formed in a portion surrounded by the protrusion 67 on the surface 60 b of the second case 60. For this reason, when the case fastening member 90 is inserted into the fifth screw hole 65, contact between the second bus bar 72 and the fourth bus bar 74 and the case fastening member 90 is suppressed.

(About battery modules)
The bolt fastening portion 50f provided on the outer surface of the first stack storage space 50a is stored in the projection plane in the vertical direction of the first flange portion 50d. Similarly, the bolt fastening portion 50f provided on the outer surface of the second stack storage space 50b is stored in the vertical projection plane of the second flange portion 50e. Thereby, the increase in the physique of the battery pack 100 is suppressed.

  The preferred embodiments of the present disclosure have been described above. However, the present disclosure is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present disclosure. It is.

(First modification)
In the present embodiment, an example in which the bolt fastening portion 50f provided on the outer surface of the first stack storage space 50a is stored in the projection plane in the vertical direction of the first flange portion 50d is shown. Similarly, an example in which the bolt fastening portion 50f provided on the outer surface of the second stack storage space 50b is stored in the projection plane in the vertical direction of the second flange portion 50e is shown. However, as shown in FIG. 11, a configuration is adopted in which a part of the bolt fastening portion 50f provided on the outer surface of the first stack storage space 50a is located outside the projection surface in the vertical direction of the first flange portion 50d. You can also. Similarly, a configuration in which a part of the bolt fastening portion 50f provided on the outer side surface of the second stack storage space 50b is located outside the projection surface in the vertical direction of the second flange portion 50e may be employed.

(Second modification)
In this embodiment, the connection terminal 70a of all the bus-bars 70 was shown in the example provided in the 1st empty part 60f and the 2nd empty part 60g. However, as shown in FIG. 12, a configuration in which a part of the plurality of connecting terminals 70a is provided in a part other than the first empty part 60f and the second empty part 60g in the second case 60 may be employed. FIG. 12 also shows that the sensor element of the sensor unit 40 can be provided in a portion other than the first empty portion 60f and the second empty portion 60g in the second case 60.

(Third Modification)
In the present embodiment, as shown in the column (a) of FIG. 13, an example in which a substantially circular space is formed by the thinned portion 72d and the thinned portion 74d, and the protruding portion 67 has a cylindrical shape is shown. However, the shape of the lightening portion 72d and the lightening portion 74d and the shape of the protrusion 67 are not limited to the above example. For example, as shown in the column (b) of FIG. 13, a substantially rectangular space may be formed by the thinned portion 72d and the thinned portion 74d, and the protrusion 67 may have a rectangular tube shape. Further, as shown in the column (c) of FIG. 13, a protrusion 67a may be formed on the side surface of the protrusion 67, and a recess 70c corresponding to the protrusion 67a may be formed in the thinned portion 72d and the thinned portion 74d. . Accordingly, the positions of the second bus bar 72 and the fourth bus bar 74 with respect to the protrusion 67 are determined.

(Fourth modification)
In the present embodiment, as shown in the column (a) of FIG. 14, the boundary between the central portion 72c and the first end portion 72a of the second bus bar 72, and the boundary between the central portion 72c and the second end portion 72b, respectively. In the example shown, is bent at a right angle. The bent shape of the boundary is the same in the fourth bus bar 74. However, for example, as shown in the column (b) of FIG. 14, it is also possible to adopt a shape in which the boundary between the central portion 72c and the second end portion 72b is curved and the central portion 72c protrudes. Of course, the fourth bus bar 74 can be used.

  Further, as schematically shown in the column (a) of FIG. 14, a guide portion 60 h that contacts the battery cell side of the central portion 72 c may be formed in the second case 60. The guide part 60 h may be formed in the second case 60 with respect to the fourth bus bar 74.

(Fifth modification)
In this embodiment, the example in which the lithium storage battery 10 has five battery cells was shown. However, the lithium storage battery 10 only needs to have a plurality of battery cells, and is not limited to the above example. Also, the number of battery stacks may be one or three or more instead of two.

(Sixth Modification)
In the present embodiment, the lead storage battery 110 is connected to the battery pack 100, and the battery pack 100 includes the lithium storage battery 10. However, the inclusion relationship between the lead storage battery 110 and the lithium storage battery 10 with respect to the battery pack 100 is not limited to the above example. The battery pack 100 can employ a configuration having at least one of a lead storage battery 110 and a lithium storage battery 10. Alternatively, a configuration in which the battery pack 100 does not include the lead storage battery 110 and the lithium storage battery 10 may be employed. In this case, each of the lead storage battery 110 and the lithium storage battery 10 is electrically connected to the battery pack 100.

(Seventh Modification)
In the present 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 employed. In this case, the starter motor 120 and the rotating electrical machine 130 shown in the present embodiment replace the motor generator.

(Eighth modification)
In the present embodiment, an example in which the switch 22 is mounted on the wiring board 21 is shown. However, the switch 22 only needs to be electrically connected to the wiring board 21 and may not be directly mounted on the wiring board 21. In the case of this modification, for example, the switch 22 is mounted on the housing via an insulating film. Thereby, the switch 22 and the housing are thermally connected. The heat generated by the switch 22 actively flows not to the wiring board 21 but to the housing. This prompts the switch 22 to radiate heat.

  As described above, the switch 22 includes the first switch 29 to the sixth switch 34. Some of these may be selectively mounted on the wiring board 21 while others may be mounted on the housing.

DESCRIPTION OF SYMBOLS 1 ... Battery module, 2 ... Connection module, 3 ... Power supply module, 10 ... Lithium storage battery, 10g ... Positive electrode terminal, 10h ... Negative electrode terminal, 10i ... 1st battery stack, 10j ... 2nd battery stack, 10l ... Packing, 11 ... 1st battery cell, 12 ... 2nd battery cell, 13 ... 3rd battery cell, 14 ... 4th battery cell, 15 ... 5th battery cell, 40 ... sensor part, 41 ... submergence sensor, 50 ... 1st case, 50c ... Center flange part, 50d ... First flange part, 50e ... Second flange part, 60 ... Second case, 60a ... Opposing surface, 60b ... Surface, 60c ... Opposing flange part, 60d ... First opposing flange part, 60e ... Second opposing flange portion, 61 ... first screw hole, 62 ... second screw hole, 63 ... third screw hole, 64 ... fourth screw hole, 65 ... fifth screw hole, 67 ... projection, 69g ... first Common groove, 6 h ... 2nd common groove, 70 ... Bus bar, 71 ... 1st bus bar, 72 ... 2nd bus bar, 72a ... 1st edge part, 72b ... 2nd edge part, 72c ... Center part, 72d ... Meat removal part, 73 ... 3rd bus bar, 74 ... 4th bus bar, 74a ... 1st end part, 74b ... 2nd end part, 74c ... Center part, 74d ... Meat removal part, 75 ... 5th bus bar, 76 ... 6th bus bar, 80 ... Voltage Detection line 81... First voltage detection line 82. Second voltage detection line 83. Third voltage detection line 84. Fourth voltage detection line 85. Fifth voltage detection line 86. , 90 ... Case fastening member, 91 ... Element fastening member, 92 ... Nut, 100 ... Battery pack

Claims (7)

A battery module (1) comprising a plurality of battery cells (11-15) and a first case (50) for housing the plurality of battery cells;
A bus bar (70 to 76) electrically and mechanically connected to the electrode terminals (10g, 10h) of the plurality of battery cells, and a voltage detection line (80 to 86) electrically and mechanically connected to the bus bar And a coupling module (2) comprising an insulating second case (60) to which the voltage detection line is mechanically connected together with the bus bar,
A battery pack in which a part of the bus bar and a part of the voltage detection line are in contact with each other on one surface (60b) of the second case. The connection module is configured to connect the bus bar and the voltage detection line in electrical contact with each other, and to connect the bus bar and the voltage detection line mechanically to the second case. Have
The back surface (60a) of the one surface in the second case faces the battery module side,
The battery pack according to claim 1, wherein the fastening member is screwed to the bus bar and the voltage detection line from the one surface toward the back surface. A plurality of individual grooves (69a to 69f) individually corresponding to the plurality of voltage detection lines are formed in the second case,
The battery pack according to claim 1, wherein the voltage detection line is provided in the individual groove. The voltage detection line is an insulated wire in which a conductive wire is covered with an insulator,
A common groove (69g, 69h) communicating with the plurality of individual grooves is formed in the second case,
The battery pack according to claim 3, wherein a plurality of the voltage detection lines are provided in the common groove. Each of the plurality of battery cells has a positive electrode terminal (10g) and a negative electrode terminal (10h) arranged in the lateral direction as the electrode terminals,
In a mode in which the positive terminals and the negative terminals of the plurality of battery cells are alternately arranged in the height direction orthogonal to the lateral direction, the plurality of battery cells are arranged in the height direction,
5. The voltage detection line according to claim 1, wherein the voltage detection line is located at a portion facing the portion between the positive electrode terminal and the negative electrode terminal of each of the plurality of battery cells in the second case. Battery pack. The connection module has sensor elements (40, 41);
Each of the plurality of battery cells has a positive electrode terminal (10g) and a negative electrode terminal (10h) arranged in the lateral direction as the electrode terminals,
In a mode in which the positive terminals and the negative terminals of the plurality of battery cells are alternately arranged in the height direction orthogonal to the lateral direction, the plurality of battery cells are arranged in the height direction,
The battery according to any one of claims 1 to 5, wherein the sensor element is located at a position opposite to a portion between the positive electrode terminal and the negative electrode terminal of each of the plurality of battery cells in the second case. pack.   Since the voltage detection line is positioned together with the sensor element at the facing portion of the second case, the second case is within the projection surface of the first case in the vertical direction in which the battery module and the connection module are arranged. The battery pack according to claim 6, wherein is located.

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