JP2019139924A - Battery pack - Google Patents

Abstract

To provide a battery pack in which an increase in the number of components is suppressed, and furthermore which can detect liquid.SOLUTION: The battery pack includes a battery cell, a casing 81 that stores the battery cell, a submergence sensor 42 that detects liquid in the casing, and the submergence sensor includes a counter electrode 43 that faces a first connection bus bar 71 connected to the ground potential in the casing.SELECTED DRAWING: Figure 8

Description

  The disclosure described herein relates to a battery pack having a battery.

  As shown in Patent Document 1, a battery pack including a submergence detection device and an assembled battery including a plurality of single cells is known.

Japanese Patent No. 5,970,849

  The submersion detection device for a battery pack disclosed in Patent Document 1 has a plurality of conductive parts (counter electrodes) in order to detect water (liquid). Therefore, there is a problem that the number of parts is large.

  Therefore, an object of the present disclosure is to provide a battery pack that can detect a liquid while suppressing an increase in the number of parts.

One of the disclosures is a plurality of battery cells (11-15);
A housing (81) for housing a plurality of battery cells;
A detection unit (27, 42) for detecting a conductive liquid in the housing,
The detection unit includes a counter electrode (43) facing the ground member (71, 81, 83, 84) connected to the ground potential in the housing.

  According to this, when the ground member (71, 81, 83, 84) and the counter electrode (43) are conducted through the liquid, the resistance value between them changes. Therefore, the liquid can be detected by detecting the change in the resistance value through one counter electrode (43). Thus, the detection unit (27, 42) can detect the liquid without having a plurality of counter electrodes. Therefore, an increase in the number of parts is suppressed.

  Note that the reference numbers in parentheses above merely indicate the correspondence with the configurations described in the embodiments described later, and do not limit the technical scope in any way.

It is a circuit diagram for demonstrating a power supply system. It is sectional drawing for demonstrating the structure of a battery pack. It is a front view which shows a battery case. It is a front view which shows the state in which the assembled battery was accommodated in the battery case. It is a front view which shows a wiring case. It is a front view which shows a connection bus bar and a sensor part. It is a front view which shows a battery module. It is sectional drawing for demonstrating the structure of a battery pack. It is a circuit diagram for demonstrating a determination circuit. It is sectional drawing which shows the modification of a battery pack. It is sectional drawing which shows the modification of a battery pack. It is sectional drawing which shows the modification of a battery pack. It is sectional drawing which shows the modification of a battery pack. It is sectional drawing which shows the modification of a battery pack. It is sectional drawing which shows the modification of a battery pack. It is sectional drawing which shows the modification of a battery pack.

  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. In FIG. 2, a sensor unit 40, a wiring case 62, and a sensor unit 40, which will be described later, are not shown.

<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 an assembled battery 10. The power supply system 200 constructs a two-power supply system by using the lead storage battery 110 and the assembled 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. The lead storage battery 110, the starter motor 120, and the electric load 150 are each electrically connected to the battery pack 100 via the first wire harness 210. The rotating electrical machine 130 is electrically connected to the battery pack 100 via the second wire harness 220.

  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 through wiring (not shown).

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

<Power system components>
The lead storage battery 110 generates an electromotive voltage by a chemical reaction. The lead storage battery 110 has a larger storage capacity than the assembled battery 10.

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

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

  The inverter converts a DC voltage supplied from at least one of the lead storage battery 110 and the assembled battery 10 of the battery pack 100 into an AC voltage. This AC voltage is supplied to the rotating electrical machine 130. Thereby, the rotating electrical machine 130 is powered.

  The rotating electrical machine 130 is connected to the engine 140. The rotating electrical machine 130 and the engine 140 can transmit rotational energy to each other via a belt or the like. The rotational energy generated by the power running of the rotating electrical machine 130 is transmitted to the engine 140. Thereby, the rotation of the engine 140 is promoted. As a result, vehicle travel is assisted. As described above, a vehicle equipped with the power supply system 200 has an idle stop function. The rotating electrical machine 130 not only assists the vehicle travel, but also functions to rotate the crankshaft when the engine 140 is restarted.

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

  The engine 140 generates driving force of the vehicle by driving the fuel to burn. As described above, when the engine 140 is started, the crankshaft is rotated by the starter motor 120. However, when the engine 140 is stopped once by the idle stop and then restarted, the crankshaft is rotated by the rotating electrical machine 130 when the predetermined starting condition is satisfied.

  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 illustrated here has a property of switching from the on state to the off state when the supply voltage falls below the reset threshold. 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 running of the rotating electrical machine 130, power generation, and the like. The host ECU 160 controls the battery pack 100. 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>
As shown in FIG. 1, the battery pack 100 includes an assembled battery 10, a circuit board 20, a switch 30, a sensor unit 40, and a power supply bus bar 50. As shown in FIGS. 2 and 6, the battery pack 100 includes a module case 60, a connecting bus bar 70, and a pack case 80.

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

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

  The first external connection terminal 100a, the fourth external connection terminal 100d, and the fifth external connection terminal 100e are electrically connected to the lead storage battery 110, the starter motor 120, and the electric load 150 via the first wire harness 210, respectively. Has been. The second external connection terminal 100 b is electrically connected to the rotating electrical machine 130 via the second wire harness 220. 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. 1, the first wire harness 210 is divided into a lead storage battery 110, a starter motor 120, and a general load 151, and a protective load 152. The ends of the first wire harness 210 connecting the lead storage battery 110, the starter motor 120, and the general load 151 are divided into two. One of the bifurcated ends is connected to the first external connection terminal 100a, and the other is connected to the fifth external connection terminal 100e. The end of the first wire harness 210 that connects the protective load 152 is connected to the fourth external connection terminal 100d.

  As shown in FIGS. 3 and 5, the module case 60 includes a battery case 61 and a wiring case 62. As shown in FIG. 4, the assembled battery 10 is stored in the battery case 61. As shown in FIG. 7, the wiring case 62 is connected to the battery case 61. As a result, the assembled battery 10 is accommodated in the battery case 61 and the wiring case 62. Further, the electrode terminals of a plurality of battery cells constituting the assembled battery 10 are electrically connected in series via a connection bus bar 70 shown in FIG. Thereby, the battery module is configured.

  The pack case 80 has a housing 81 and a cover 82. The housing 81 and the cover 82 constitute a storage space. The battery pack 10, the module case 60, the connection bus bar 70, the circuit board 20, the switch 30, the sensor unit 40, and the power supply bus bar 50 are stored in this storage space.

<Battery pack components>
The assembled battery 10 has a plurality of battery cells. This battery cell is specifically 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 and generates gas. Therefore, the battery cell expands. The battery cell is not limited to the above example. For example, a secondary battery such as a nickel hydride secondary battery or an organic radical battery can be used as the battery cell.

  As described above, the circuit board 20 includes the wiring board 21 and the BMU 22. The wiring board 21 is a printed board in which a wiring pattern made of a conductive material is formed on an insulating board. A first feed line 23, a second feed line 24, and a third feed line 25 are formed as wiring patterns on at least one of the surface and the inside of the insulating substrate. As shown in FIG. 2, the wiring board 21 (circuit board 20) is provided between the battery case 61 (module case 60) and the cover 82.

  A conductive plate (not shown) is fixed to the wiring board 21. Bolt holes are formed in the conductive plate. Bolts are passed through the bolt holes of the conductive plate. Bolts are fixed to the casing 81. Thereby, the wiring board 21 is mechanically and electrically connected to the housing 81. The electrical connection between the wiring board 21 and the housing 81 is simply shown by the connection wiring 20a in FIGS.

  As will be described later, the casing 81 is connected to the ground potential. For this purpose, the conductive plate of the wiring board 21 is connected to the ground potential. The BMU 22 mounted on the wiring board 21 uses the potential of this conductive plate as a reference potential.

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

  The switch 30 includes a first switch 31, a second switch 32, a third switch 33, a fourth switch 34, a fifth switch 35, and a sixth switch 36. The first switch 31 and the second switch 32 are mounted on the housing 81. The third switch 33 and the fourth switch 34, and the fifth switch 35 and the sixth switch 36 are mounted on the wiring board 21, respectively.

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

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

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

  Each of the first switch 31 to the fourth switch 34 has at least one open / close section in which two MOSFETs are connected in series. The source electrodes of these two MOSFETs are connected to each other. The gate electrodes of the two MOSFETs are electrically independent. The MOSFET has a parasitic diode. The anode electrodes of the parasitic diodes of the two MOSFETs are connected to each other. The gate electrode is electrically connected to the circuit board 20 via an internal conductive member (not shown).

  The first switch 31 and the second switch 32 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 33 has one opening / closing part. The fourth switch 34 has a plurality of opening / closing sections. The plurality of open / close sections of the fourth switch 34 are connected in series.

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

  Each of the first switch 31 to the fourth switch 34 has a resin part that covers the opening / closing part. This resin part has a rectangular parallelepiped shape. The resin portion has a flat shape with a thin length (thickness) between two main surfaces having the largest area.

  Bolt holes penetrating the two main surfaces are formed in the resin portions of the first switch 31 and the second switch 32, respectively. A mounting hole corresponding to the bolt hole of the resin portion is formed in the housing 81. Bolts are fastened to the bolt holes of the resin portion and the mounting holes of the housing 81. As a result, the first switch 31 and the second switch 32 are fixed to the casing 81 and thermally connected. An insulating film is provided between the resin part and the heat dissipation part.

  As described above, the sensor unit 40 is electrically connected to the electric circuit. The sensor unit 40 includes sensor elements that detect the states of the assembled battery 10 and the switch 30. 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 assembled battery 10. The sensor unit 40 outputs it to the BMU 22 as a status signal of the assembled battery 10. The sensor unit 40 detects the temperature, current, and voltage of the switch 30. The sensor unit 40 outputs it to the BMU 22 as a status signal of the switch 30. 6-8, the voltage sensor 41 which detects the voltage of the assembled battery 10 is shown as a representative of these several sensors. The voltage sensor 41 is an insulated wire connected to the connection bus bar 70.

  The sensor unit 40 includes a submergence sensor 42 in addition to the various sensors described above. The submergence sensor 42 has one counter electrode 43. The counter electrode 43 is disposed to face the first connection bus bar 71 connected to the ground potential. If there is a liquid such as water between the counter electrode 43 and the first connection bus bar 71, they are conducted. As a result, the resistance between the counter electrode 43 and the first connection bus bar 71 changes. The BMU 22 detects this resistance change. The BMU 22 detects the submersion of the battery pack 100 based on whether or not the resistance change is continued for a predetermined time. Detection of submersion by the BMU 22 will be described later.

  The BMU 22 controls the switch 30 based on at least one of the status signal of the sensor unit 40 and the command signal from the host ECU 160. As described above, each of the first switch 31 to the fourth switch 34 includes a plurality of semiconductor switches. For example, when controlling the opening and closing of the first switch 31, the BMU 22 controls all the semiconductor switches included in the first switch 31 to the closed state or the open state simultaneously. That is, the BMU 22 simultaneously outputs a high level control signal or a low level control signal to the gate electrodes of all the semiconductor switches of the first switch 31. Note that the BMU 22 may adjust the closing time of the semiconductor switch by intermittently outputting a high-level control signal during the period in which the semiconductor switch is closed. In short, the BMU 22 may control the pulse width of the semiconductor switch. BMU is an abbreviation for battery management unit.

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

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

  The BMU 22 controls the switch 30 based on a command signal from the host ECU 160. When the BMU 22 determines that the battery pack 100 has been submerged based on the state signal of the submergence sensor 42, the BMU 22 arbitrarily stops the output of the control signal to the switch 30. Thereby, the electrical connection of the assembled battery 10 is interrupted.

  Further, the BMU 22 restricts the drive of the switch 30 when the switch 30 becomes high temperature. For example, when the BMU 22 is controlling the pulse width of the semiconductor switch of the switch 30, the BMU 22 decreases its duty ratio. This shortens the energization time of the semiconductor switch. As a result, heat generation of the semiconductor switch is suppressed.

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

  The battery pack 100 includes a first power supply bus bar 51, a second power supply bus bar 52, a third power supply bus bar 53, and a fourth power supply bus bar 54 as the power supply bus bar 50. The circuit board 20 and the assembled battery 10 and the circuit board 20 and the external connection terminal are electrically connected by the plurality of power supply bus bars. In FIG. 1, each of these power supply bus bars is shown thicker than the power supply line of the wiring board 21. These power supply bus bars are provided on an insulating resin base (not shown). The resin stand is disposed to face the wiring case 62 in the vertical direction.

  As described above, the module case 60 includes the battery case 61 and the wiring case 62. Each of the battery case 61 and the wiring case 62 is made of an insulating resin material. The specific heat of each of the battery case 61 and the wiring case 62 is higher than that of air. The assembled battery 10 is housed in a space formed by the battery case 61 and the wiring case 62.

  The connection bus bar 70 is formed by a manufacturing method equivalent to that of the power supply bus bar 50. The connecting bus bar 70 is provided in the wiring case 62. The connection bus bar 70 electrically and mechanically connects a plurality of battery cells included in the assembled battery 10.

  As described above, the pack case 80 includes the housing 81 and the cover 82. The casing 81 can be manufactured by aluminum die casting. The casing 81 can also be manufactured by pressing iron or stainless steel. The housing 81 includes a bottom wall 83 and a side wall 84 that rises annularly from the bottom surface 83 a of the bottom wall 83. An opening is constituted by the annular side wall 84. This opening is covered with a cover 82. This constitutes a storage space. The cover 82 is made of resin or metal.

  Although not shown, a hole corresponding to the third external connection terminal 100c is formed in the bottom wall 83. The bottom wall 83 is mechanically and electrically connected to the vehicle body through bolts inserted into the holes. As a result, the casing 81 is at the ground potential.

  The pack case 80 (battery pack 100) of the present embodiment is provided below the seat of the vehicle. However, the arrangement of the battery pack 100 is not limited to this. For example, the battery pack 100 can be disposed in a space between the rear seat and the trunk room, a space between the driver seat and the passenger seat, and the like.

<Battery pack circuit configuration>
Next, the circuit configuration of the battery pack 100 will be described. As shown in FIG. 1, the first external connection terminal 100 a and one end of the first switch 31 are electrically connected via a first power supply bus bar 51. A part branches from the first power supply bus bar 51. The branch portion 51 a of the first power supply bus bar 51 is electrically connected to the first internal terminal 26 a of the wiring board 21.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  In addition, connection with each above-mentioned electric power feeding bus bar and each switch is performed by TIG welding. Each power supply bus bar and the external connection terminal are connected by bolting. Each power supply bus bar and the circuit board 20 are connected by brazing.

<Configuration of battery module>
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. The lateral direction is along the left-right direction of the vehicle. The height direction is along the vertical direction of the vehicle. When the vehicle is stopped on a horizontal plane, the height direction is along the vertical direction. The horizontal and vertical directions are along the horizontal direction.

  As described above, the assembled battery 10 has a plurality of battery cells. This battery cell has a rectangular parallelepiped shape. For this purpose, the battery cell has six sides. As shown in FIG. 2, 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 facing in the vertical direction. Although not shown, the battery cell also has a lower end surface facing in the vertical direction. Of these six surfaces, the first main surface 10a and the second main surface 10b have a larger area than the other four surfaces. The battery cell has a 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 terminal 10g and the negative terminal 10h have a rectangular parallelepiped shape. The positive electrode terminal 10g and the negative electrode terminal 10h protrude along the vertical direction from the upper end surface 10e so as to be separated from the battery cell.

  The positive electrode terminal 10g and the negative electrode terminal 10h are arranged 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.

  As shown in FIGS. 2 and 4, a safety valve 10i having a locally low rigidity is formed between the positive electrode terminal 10g and the negative electrode terminal 10h on the upper end surface 10e. As described above, the battery cell expands due to the generation of gas. When the internal pressure of the battery cell increases due to the generation of gas, the safety valve 10i is cracked. Thereby, the gas of a battery cell is discharged | emitted from the safety valve 10i outside.

  As shown in FIG. 4, the packing 10j is provided in the non-formation area | region of the positive electrode terminal 10g, the negative electrode terminal 10h, and the safety valve 10i in the upper end surface 10e. The packing 10j is made of an elastic material such as rubber. The packing 10j has an annular shape that opens in the vertical direction. The packing 10j is longer in the vertical direction than the positive terminal 10g and the negative terminal 10h. The packing 10 j is sandwiched between the battery cell and the wiring case 62 by the connection between the battery case 61 and the wiring case 62.

  The assembled 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. A battery stack is configured by arranging the plurality of battery cells. The plurality of battery cells are electrically connected in series. The first battery cell 11 becomes the battery cell having the lowest potential. The fifth battery cell 15 becomes the highest potential battery cell.

  In the present embodiment, a first battery stack 101 and a second battery stack 10m are configured as the battery stack. Of the five battery cells, the first battery cell 11, the fourth battery cell 14, and the fifth battery cell 15 are distributed to the first battery stack 10l. The remaining second battery cells 12 and third battery cells 13 are distributed to the second battery stack 10m.

  As shown in FIG. 2, in the first battery stack 101, the first battery cell 11, the fourth battery cell 14, and the fifth battery are sequentially arranged in the height direction from the bottom wall 83 of the housing 81 toward the cover 82. Cells 15 are lined up. In the second battery stack 10m, the second battery cell 12 and the third battery cell 13 are arranged in order from the bottom wall 83 toward the cover 82 in the height direction. These battery stacks are stored in the battery case 61.

  The battery case 61 has a box shape opening in the vertical direction. As shown in FIG. 3, the battery case 61 has a bottom wall 63 facing in the vertical direction and a peripheral wall 64 erected in an annular shape in the vertical direction from the inner surface 61 a of the bottom wall 63. An opening window 63a is formed in the bottom wall 63 so as to penetrate the inner surface 61a and the outer surface on the back side in the vertical direction. The inside of the battery case 61 (module case 60) is communicated with the outside by the opening window 63a.

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

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

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

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

  The first storage space 64i and the second storage space 64j are arranged in the horizontal direction. The fourth storage space 64l and the third storage space 64k are arranged in the horizontal direction. An empty space for one storage space is formed on the third storage space 64k side in the lateral direction of the fifth storage space 64m. As shown in FIG. 2, at least a part of the circuit board 20 is provided in this empty space. Therefore, at least a part of the circuit board 20 is aligned with the fifth storage space 64m in the lateral direction.

  Each of these five storage spaces is open in the vertical direction. A battery cell is inserted into the opening of the storage space. Each battery cell is inserted into the corresponding storage space until the lower end surface of the battery cell comes into contact with the inner surface 61 a of the bottom wall 63 of the battery case 61. In this inserted state, the positive electrode terminal 10g and the negative electrode terminal 10h of each battery cell protrude out of the storage space. Further, the upper end surface 10e side of each of the first main surface 10a, the second main surface 10b, the first side surface 10c, and the second side surface 10d of the battery cell also protrudes out of the battery case 61.

  As shown in FIG. 4, in the first stack storage space 64f, the second main surfaces 10b of the first battery cell 11 and the fourth battery cell 14 face each other in the height direction. The first main surfaces 10a of the fourth battery cell 14 and the fifth battery cell 15 face each other in the height direction. Thereby, the positive electrode terminals 10g and the negative electrode terminals 10h are alternately arranged in the height direction.

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

  And the positive electrode terminal 10g of the 1st battery cell 11 and the negative electrode terminal 10h of the 2nd battery cell 12 are located in a line with the horizontal direction. The negative electrode terminal 10h of the fourth battery cell 14 and the positive electrode terminal 10g of the third battery cell 13 are arranged in the horizontal direction.

  In addition to the bottom wall 63 and the peripheral wall 64 described above, the battery case 61 has a first flange extending in a direction away from the center of the battery case 61 along a plane defined by the lateral direction and the height direction from the tip of the peripheral wall 64. Part 65. In FIG. 2, the boundary between the first flange portion 65 and the peripheral wall 64 is indicated by a broken line. The first flange portion 65 is formed on each of the upper wall 64a, the right wall 64d, the lower wall 64b, and the left wall 64c of the peripheral wall 64 to form an annular shape.

  A plurality of first screw holes 61c extending in the vertical direction are formed at portions formed in the right wall 64d and the left wall 64c of the first flange portion 65, respectively. A first screw hole 61c is also formed in the first partition wall 64e. Each of the plurality of first screw holes 61 c is open to the inner surface 61 a of the battery case 61.

  As shown in FIG. 5, the wiring case 62 has a shape extending in the lateral direction. The part of the wiring case 62 facing the battery cell is recessed in the longitudinal direction away from the battery case 61. As a result, the wiring case 62 has a box shape opening in the vertical direction.

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

  The annular wall 67 has an upper wall 67a and a lower wall 67b arranged in the height direction, and a left wall 67c and a right wall 67d arranged in the horizontal direction. In the circumferential direction around the vertical direction, the upper wall 67a, the right wall 67d, the lower wall 67b, and the left wall 67c are sequentially connected to form an annular shape.

  As shown in FIGS. 5 and 6, in addition to the lid wall 66 and the annular wall 67, the wiring case 62 includes the wiring case 62 along a plane defined by the lateral direction and the height direction from the tip of the annular wall 67. It has the 2nd flange part 68 extended in the direction away from a center. The second flange portion 68 is formed on each of the upper wall 67a, the right wall 67d, the lower wall 67b, and the left wall 67c of the annular wall 67 to form an annular shape.

  A plurality of second screw holes 62c along the vertical direction are formed in the portions formed in the right wall 67d and the left wall 67c of the second flange portion 68, respectively. Further, as shown in FIG. 5, a second screw hole 62c is formed in a portion of the lid wall 66 facing the first partition wall 64e. Each of the plurality of second screw holes 62c opens on the inner surface of the wiring case 62 and the outer surface 62b on the back side thereof.

  A first recess 69 that is locally recessed toward the battery case 61 is formed at a portion of the lid wall 66 that faces the first partition wall 64e. A part of the plurality of second screw holes 62 c is formed at the bottom of the first recess 69. The vertical lengths (thicknesses) of the bottom portion and the second flange portion 68 are equal.

  The wiring case 62 is provided in the battery case 61 so as to close the opening of the storage space of the battery case 61 and cover a portion of the battery cell that protrudes outward from the opening of the battery case 61. By installing the wiring case 62 on the battery case 61, the inner surface 61a of the battery case 61 where the first screw hole 61c is opened and the inner surface of the wiring case 62 where the second screw hole 62c is opened face each other in the vertical direction.

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

  The screw member 60b shown in FIG. 7 and FIG. 8 is fastened to each of the plurality of synthetic screw holes formed by arranging the second screw holes 62c, the collar, and the first screw holes 61c in the vertical direction. As a result, the battery case 61 and the wiring case 62 are mechanically connected (coupled) so as to approach each other in the vertical direction. In this connected state, the wiring case 62 is housed in the vertical projection surface of the battery case 61.

  In addition, the thread groove should just be formed in at least one of the 1st screw hole 61c and the 2nd screw hole 62c. When the first screw hole 61c opens on the outer surface side of the battery case 61 and the tip of the screw shaft of the screw member 60b protrudes outward therefrom, a nut is fastened to the tip of the screw shaft.

  Due to the connection between the battery case 61 and the wiring case 62, the packing 10 j provided on the upper end surface 10 e of the battery cell is compressed in the vertical direction between the battery cell and the wiring case 62. Thereby, the restoring force which goes to the direction away from packing 10j along a vertical direction generate | occur | produces in packing 10j. The battery cell is pressed in the vertical direction by this restoring force. The battery cell is sandwiched between the packing 10 j and the bottom wall 63 of the battery case 61. Thereby, the vertical displacement and expansion of the battery cell are suppressed.

  As described above, the battery cell has the first main surface 10a and the second main surface 10b facing in the height direction. The first main surface 10a and the second main surface 10b are larger in area than the other four surfaces. Therefore, each battery cell is easily expanded in the height direction. As shown in FIG. 2, a holding plate 85 for suppressing the expansion of the battery cell in the height direction is provided between the upper wall 64 a of the battery case 61 and the cover 82. The holding plate 85 is connected to the bottom wall 83 of the housing 81 by bolts or the like. Thus, the module case 60 that houses the assembled battery 10 is provided between the holding plate 85 and the bottom wall 83. Due to the holding plate 85 and the bottom wall 83, the expansion in the height direction of the battery module in which the assembled battery 10 is housed in the module case 60 is suppressed.

  As shown in FIG. 5, the lid wall 66 of the wiring case 62 is formed with a plurality of openings for electrically connecting the first battery cell 11 to the fifth battery cell 15 and the connection bus bar 70. The plurality of openings penetrates the lid wall 66 along the vertical direction. The opening opens to the inner surface and the outer surface 62b of the lid wall 66.

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

  In a state where the wiring case 62 is connected to the battery case 61, the first opening 66a is formed in a portion of the lid wall 66 that faces the negative electrode terminal 10h of the first battery cell 11 in the vertical direction. The second opening 66b is formed in a portion of the lid wall 66 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 the portion of the lid wall 66 that faces the positive terminal 10g of the second battery cell 12 in the vertical direction and the portion that faces the negative terminal 10h of the third battery cell 13 in the vertical direction. ing. The fourth opening 66d is formed in a portion of the lid wall 66 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 lid wall 66 that faces the positive terminal 10g of the fourth battery cell 14 in the vertical direction and a portion that faces the negative terminal 10h of the fifth battery cell 15 in the vertical direction. ing. The sixth opening 66f is formed in a portion of the lid wall 66 that faces the positive electrode terminal 10g of the fifth battery cell 15 in the vertical direction.

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

  The lid wall 66 is formed with a plurality of second recesses 77 that are recessed locally on the battery case 61 side corresponding to the connecting bus bar 70. A first opening 66 a to a sixth opening 66 f are formed at the bottom of each of the plurality of second recesses 77.

  The vertical length of the bottom of the second recess 77 is shorter than the vertical length of each of the positive electrode terminal 10g and the negative electrode terminal 10h. Therefore, the vertical length of each opening is also shorter than the vertical length of each of the positive electrode terminal 10g and the negative electrode terminal 10h. Each of the positive terminal 10g and the negative terminal 10h protrudes outside the module case 60 through each opening.

  The 1st connection bus bar 71 is provided in the outer surface 62b side of the 2nd recessed part 77 in the aspect which obstruct | occludes the 1st opening part 66a. The part provided in the first opening 66a in the first connection bus bar 71 is mechanically and electrically connected to the negative electrode terminal 10h of the first battery cell 11 by laser welding or the like.

  A negative connection terminal (not shown) is formed on the first connection bus bar 71. The minus connection terminal functions as a minus output terminal of the battery pack 10. The minus connection terminal is electrically connected to the casing 81 via a fuse (not shown). As a result, the first connection bus bar 71 is at the ground potential.

  The 2nd connection bus bar 72 is provided in the outer surface 62b side of the 2nd recessed part 77 in the aspect which obstruct | occludes the 2nd opening part 66b. The second connecting bus bar 72 has a shape extending in the lateral direction. The part provided in the second opening 66b in the second connection 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. Is done. Thereby, the first battery cell 11 and the second battery cell 12 are connected in series via the second connection bus bar 72.

  The 3rd connection bus bar 73 is provided in the outer surface 62b side of the 2nd recessed part 77 in the aspect which obstruct | occludes the 3rd opening part 66c. The third connection bus bar 73 has a shape extending in the height direction. The part provided in the third opening 66c in the third connection 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. Is done. Accordingly, the second battery cell 12 and the third battery cell 13 are connected in series via the third connection bus bar 73.

  The fourth connecting bus bar 74 is provided on the outer surface 62b side of the second recess 77 in a manner to close the fourth opening 66d. The fourth connecting bus bar 74 has a shape extending in the lateral direction. The part provided in the fourth opening 66d of the fourth connection 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. Is done. Thereby, the third battery cell 13 and the fourth battery cell 14 are connected in series via the fourth connection bus bar 74.

  The fifth connecting bus bar 75 is provided on the outer surface 62b side of the second recess 77 in a manner to close the fifth opening 66e. The fifth connecting bus bar 75 has a shape extending in the height direction. The part provided in the fifth opening 66e in the fifth connection 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. Is done. As a result, the fourth battery cell 14 and the fifth battery cell 15 are connected in series via the fifth connection bus bar 75.

  The sixth connection bus bar 76 is provided on the outer surface 62b side of the second recess 77 so as to close the sixth opening 66f. The part provided in the sixth opening 66f of the sixth connection bus bar 76 is mechanically and electrically connected to the positive terminal 10g of the fifth battery cell 15 by laser welding or the like.

  A positive connection terminal (not shown) is formed on the sixth connection bus bar 76. This plus connection terminal functions as a plus output terminal of the battery pack 10.

<Sensor part>
Next, the sensor unit 40 will be described in detail.

  As described above, the connection bus bar 70 includes the first connection bus bar 71 to the sixth connection bus bar 76. The voltage sensor 41 has a first voltage wiring 41a to a sixth voltage wiring 41f that are electrically connected independently to the first connection bus bar 71 to the sixth connection bus bar 76, respectively. The first voltage wiring 41a to the sixth voltage wiring 41f correspond to a plurality of voltage detection lines.

  As shown in FIG. 8, the first connection bus bar 71 and the fifth connection bus bar 75 are located on the right wall 67 d side of the lid wall 66. The 2nd connection bus bar 72, the 4th connection bus bar 74, and the 6th connection bus bar 76 are located in the center side of lid wall 66 in the horizontal direction. Thus, a space is formed between the right wall 67d side and the center side of the lid wall 66. Hereinafter, this space is referred to as a first space.

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

  Each of the first voltage wiring 41 a, the fourth voltage wiring 41 d, the fifth voltage wiring 41 e, and the sixth voltage wiring 41 f is provided in the first space of the lid wall 66. And one end of these four voltage wirings is bolted to the 1st space side of a corresponding connection bus bar. These four voltage wires extend from the corresponding connecting bus bar to the upper wall 67a side of the first space.

  Each of the second voltage wiring 41 b and the third voltage wiring 41 c is provided in the second space of the lid wall 66. One end of these two voltage wires is bolted to the second space side of the corresponding connecting bus bar. These two voltage wirings extend from the corresponding connecting bus bar to the upper wall 67a side of the second space, and then extend to the first space side along the shape of the upper wall 67a. The two voltage wirings provided in the second space are grouped together with the four voltage wirings provided in the first space on the first space side.

  As described above, the submergence sensor 42 has the counter electrode 43 that faces the first connection bus bar 71. The submergence sensor 42 has a connection wiring 44 connected to the counter electrode 43. This connection wiring 44 is an insulated wire.

  The counter electrode 43 is provided in the first space of the lid wall 66 described above. The counter electrode 43 is opposed to the first connecting bus bar 71 in a lateral direction. The counter electrode 43 is opposed to the bottom wall 83 of the housing 81 in the height direction.

  The facing distance FD1 between the facing electrode 43 and the first connecting bus bar 71 in the lateral direction is shorter than the facing distance FD2 between the facing electrode 43 and the bottom wall 83 in the height direction. Therefore, the resistance between the counter electrode 43 and the first connection bus bar 71 is higher than that between the counter electrode 43 and the bottom wall 83.

  In the present embodiment, the counter electrode 43 is not opposed to the connection portion of the first connection bus bar 71 with the first voltage detection line 41a. However, the counter electrode 43 may be configured to face the connection portion of the first connection bus bar 71 with the first voltage detection line 41a. A connection portion of the first connection bus bar 71 with the first voltage detection line 41a locally protrudes. For this reason, the locally projecting portion is positioned on the bottom wall 83 side, for example, the connecting portion of the first connecting bus bar 71 with the first voltage detection line 41a. Thereby, the structure etc. which shortened the separation distance of the counter electrode 43 and the 1st connection bus bar 71 locally are employable.

  The connection wiring 44 is provided in the first space of the lid wall 66. One end of the connection wiring 44 is connected to the counter electrode 43. The connection wiring 44 extends from the counter electrode 43 to the upper wall 67a side of the first space. The connecting wiring 44 merges into six voltage wirings and is combined into one together. Although not shown, these seven wires are grouped together by a regulating member fixed to the wiring case 62.

  The seven wirings forming these bundles extend from the part gathered by the regulating member to the wiring board 21 side. The other ends of these seven wirings are collected in the first connector 45. Although not shown, other sensors for detecting current and temperature also have insulated wires, and these insulated wires are also grouped together with the seven wires by the above-described regulating member. The other ends of these insulated wires are also collected in the first connector 45.

  As shown in FIGS. 2 and 8, the wiring board 21 is provided with a second connector 46 connected to the first connector 45. The first connector 45 is inserted into the second connector 46. As a result, a signal (state signal) detected by the sensor unit 40 is input to the BMU 22.

<Determination circuit>
As shown in FIG. 9, the BMU 22 includes a determination circuit 27 that determines whether or not a liquid such as water having conductivity because it contains impurities is between the counter electrode 43 and the first connection bus bar 71. The determination circuit 27 is based on the output circuit 28 in which the voltage level (output voltage) of the output signal changes according to the change in the resistance value between the counter electrode 43 and the first connection bus bar 71, and the output voltage of the output circuit 28. And a determination circuit 29 for determining whether the battery pack 100 is submerged or not. The determination circuit 27 and the submergence sensor 42 correspond to a detection unit. The first connection bus bar 71 corresponds to a ground member and an electrode plate.

  The output circuit 28 includes a switch 28a, a first resistor 28b, and a second resistor 28c. The switch 28a and the first resistor 28b are connected in series in order from the power supply to the ground. The second resistor 28c is connected to the midpoint between the switch 28a and the first resistor 28b. With this connection configuration, when the switch 28a is in the open state, the midpoint between the switch 28a and the first resistor 28b becomes the ground potential (low level). When the switch 28a is in the closed state, the midpoint between the switch 28a and the first resistor 28b is at a high level. This midpoint potential is input as an output voltage of the output circuit 28 to the determination circuit 29 via the second resistor 28c.

  The switch 28a is a P-channel MOSFET. The source electrode of the switch 28a is connected to the power source. The drain electrode of the switch 28a is connected to the first resistor 28b and the second resistor 28c.

  The output circuit 28 has a reference resistor 28d that connects the source electrode and the gate electrode of the switch 28a. A midpoint between the reference resistor 28d and the gate electrode is electrically connected to the counter electrode 43.

  The open / close state of the switch 28a changes depending on the potential difference between the source electrode and the gate electrode. When the potential of the gate electrode is higher than the potential of the source electrode, the switch 28a is in an open state. Even when the potential of the gate electrode is lower than the potential of the source electrode, if the potential difference is lower than the threshold voltage of the switch 28a, the switch 28a is open. When the potential of the gate electrode is lower than the potential of the source electrode and the potential difference exceeds the threshold voltage, the switch 28a is closed. In the following, for ease of explanation, the potential difference between the source electrode and the gate electrode is denoted as Vgs, and the threshold voltage is denoted as Vth.

  When there is no conductive liquid between the counter electrode 43 and the first connection bus bar 71 connected to the ground potential and both are non-conductive, the counter electrode 43 is opened. Therefore, no current flows through the counter electrode 43, and the gate electrode is at the power supply potential. The potential difference Vgs is almost zero, and the switch 28a is open. The midpoint between the switch 28a and the first resistor 28b is at a low level. This low level is input to the determination circuit 29. In this case, the determination circuit 29 determines that the battery pack 100 is not submerged.

  When there is a liquid having conductivity between the counter electrode 43 and the first connection bus bar 71, and the two are thereby conducted, the determination circuit 27 includes a series circuit having the liquid as a resistance. Assuming that the resistance formed of the conductive liquid is Wa, the determination circuit 27 includes a series circuit including a reference resistance 28d and a resistance Wa that are sequentially connected from the power source to the ground. A midpoint between the reference resistor 28d and the resistor Wa is connected to the gate electrode of the switch 28a.

  When the resistance value of the reference resistor 28d is Rc, the resistance value of the resistor Wa is Rw, and the power supply voltage is V, the voltage input to the gate electrode is Rw × V / (Rc + Rw). On the other hand, the voltage input to the source electrode is V. The potential of the gate electrode is lower than the potential of the source electrode. The potential difference Vgs is Rc × V / (Rc + Rw).

  The resistance value Rw is determined by the conductivity of the liquid, the facing distance FD1 between the facing electrode 43 and the first connection bus bar 71, and the facing area. Since the liquid is a detection target, its conductivity cannot be selected. However, the facing distance FD1 and the facing area between the facing electrode 43 and the first connection bus bar 71 can be appropriately selected according to the application. Therefore, for example, the resistance value Rw can be set low by setting the facing distance FD1 short.

  As the resistance value Rw decreases, the potential difference Vgs increases. The potential difference Vgs exceeds the threshold voltage Vth, and the switch 28a is closed. As a result, the midpoint between the switch 28a and the first resistor 28b becomes high level. This high level is input to the determination circuit 29. When the input of the high level signal is continued for a predetermined time such as 1 second, the determination circuit 29 determines that the battery pack 100 is submerged. Of course, the predetermined time is only an example, and for example, 0.5 seconds or 0.1 seconds can be selected as appropriate.

  Incidentally, as described above, the facing distance FD2 in the height direction between the facing electrode 43 and the bottom wall 83 is longer than the facing distance FD1. Therefore, the resistance constituted by the liquid that conducts the counter electrode 43 and the bottom wall 83 has a higher resistance value than the resistance constituted by the liquid that conducts the counter electrode 43 and the first connection bus bar 71. In the present embodiment, when there is a liquid such as tap water between the counter electrode 43 and the bottom wall 83, the potential difference Vgs is set so as not to exceed the threshold voltage Vth due to conduction between the two. Therefore, in the case of the configuration shown in the present embodiment, if water or the like enters the casing 81 and the water is positioned between the counter electrode 43 and the first connection bus bar 71 and does not conduct both, the output circuit 28 is The high level signal is not output. Of course, the potential difference Vgs may be set to exceed the threshold voltage Vth when the counter electrode 43 and the bottom wall 83 are electrically connected by a liquid such as tap water.

  In this embodiment, the resistance value Rw when the counter electrode 43 and the first connection bus bar 71 are opposed to each other and the area of the counter electrode 43 and the first connecting bus bar 71 when they are conducted by a conductive liquid because they contain some impurities such as tap water. It is set to be several tens of kΩ. The electrical resistivity of tap water is approximately 100 Ω · m. On the other hand, the facing distance between the counter electrode 43 and the first connection bus bar 71 is set to, for example, several mm, and the facing area is set to, for example, several square mm.

  However, water droplets are formed on the surfaces of the counter electrode 43 and the first connection bus bar 71 by condensation. Water drops gradually grow and become heavier. Water drops try to flow down by their own weight. However, there is a possibility that the water droplets formed on the surfaces of the counter electrode 43 and the first connection bus bar 71 are connected to each other before the water droplets flow down due to their own weight. Thereby, there exists a possibility that the counter electrode 43 and the 1st connection bus bar 71 may be conduct | electrically_connected. Thus, the shortest facing distance between the counter electrode 43 and the first connecting bus bar 71 is determined so that the counter electrode 43 and the first connecting bus bar 71 are prevented from conducting through the water droplets.

<Effect>
As described above, when the counter electrode 43 for submergence detection and the first connection bus bar 71 for ground connection of the assembled battery 10 are conducted through a liquid such as water having conductivity because they contain impurities, between them Resistance changes. The voltage level of the output circuit 28 varies according to the change in resistance. Thereby, it is possible to detect whether or not there is liquid in the casing 81 in which the counter electrode 43 and the first connection bus bar 71 are provided. As described above, the submergence sensor 42 can detect liquid without having a plurality of counter electrodes for submergence detection. Therefore, an increase in the number of parts of battery pack 100 is suppressed.

  The counter electrode 43 is connected to the connection wiring 44. The voltage sensor 41 includes a first voltage wiring 41a to a sixth voltage wiring 41f. The connection wiring 44 and the first voltage wiring 41 a to the sixth voltage wiring 41 f are insulated wires, and the other ends thereof are gathered together in the first connector 45. The first connector 45 is connected to a second connector 46 provided on the wiring board 21. According to this, the configuration of the battery pack 100 is simplified as compared with the configuration in which the connection wiring and the plurality of voltage wirings are individually connected to the wiring board 21.

  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)
A shape in which a part of the first connection bus bar 71 extends toward the bottom wall 83 of the housing 81 as shown in FIG. An extension portion 71a of the first connection bus bar 71 extending to the bottom wall 83 and the counter electrode 43 are disposed to face each other in the lateral direction. Thereby, the liquid that has entered the housing 81 can be detected earlier.

(Second modification)
As shown in FIGS. 11 and 12, a configuration in which the counter electrode 43 faces the bottom wall 83 in the height direction may be employed. In this modification, the counter electrode 43 and the bottom wall 83 are output so that a high level is output from the output circuit 28 when the counter electrode 43 and the bottom wall 83 are electrically connected by a liquid having an electrical resistivity equivalent to tap water. The facing distance FD2 and the facing area with respect to 83 are determined. In the modification shown in FIG. 11, the counter electrode 43 is fixed to the lower wall 67b. In the modification shown in FIG. 12, the counter electrode 43 is fixed at a position facing the bottom wall 83 of the second flange portion 68. The casing 81 corresponds to a ground member.

(Third Modification)
In each embodiment, the example in which the connection wiring 44 is provided in the first space of the lid wall 66 is shown. However, for example, a configuration in which the connection wiring 44 is provided on the annular wall 67 as shown in FIG.

(Fourth modification)
As shown in FIG. 14, a configuration in which the counter electrode 43 faces the side wall 84 in the lateral direction can also be adopted. In this modification, a high level is output from the output circuit 28 when the counter electrode 43 and the side wall 84 are made conductive by a liquid having an electrical resistivity equivalent to tap water.

(Fifth modification)
In the present embodiment, an example in which the sensor unit 40 has one submerged sensor 42 is shown. However, the number of submerged sensors 42 included in the sensor unit 40 is not limited to the above example. For example, as shown in FIG. 15, the sensor unit 40 may include two submersion sensors 42. In the modification shown in FIG. 15, the counter electrodes 43 of the two submersion sensors 42 are spaced apart in the lateral direction. Each counter electrode 43 is opposed to a portion of the side wall 84 that is disposed opposite to the side wall 84 in the lateral direction. According to this, even if one of the two opposing electrodes 43 is positioned on the upper side in the vertical direction compared to the other due to the inclination of the ground on which the vehicle is placed, the other is positioned on the lower side in the vertical direction. To do. Therefore, even if it becomes difficult to detect the liquid on one of the two counter electrodes 43, the liquid can be detected on the other. In this modification, not only the liquid between the counter electrode 43 and the side wall 84 but also the liquid between the counter electrode 43 and the bottom wall 83 can be detected.

(Sixth Modification)
In the present embodiment and the various modifications shown so far, the example in which the counter electrode 43 is positioned on the bottom wall 83 side of the housing 81 has been shown. However, for example, as shown in FIG. 16, the counter electrode 43 may be positioned on the opening side (the cover 82 side) of the housing 81. According to this, when the liquid flows in from the opening of the casing 81, the counter electrode 43 and the side wall 84 are electrically connected by the liquid. Therefore, the liquid can be detected before the liquid is accumulated in the casing 81.

  The number and arrangement of the submergence sensors 42 can be appropriately determined according to the shape of the battery pack 100 and the arrangement position and arrangement angle of the battery pack 100 on the vehicle. For example, a plurality of submersion sensors may be arranged side by side at the same height position. For example, a plurality of submersion sensors may be arranged side by side in the height direction.

  In the present embodiment, the counter electrode 43 is provided on the wiring case 62. However, the position where the counter electrode 43 is provided is not particularly limited as long as the counter electrode 43 is disposed so as to be opposed to the portion made of the conductive material having the ground potential in the housing 81. For example, the counter electrode 43 may be provided on the battery case 61. Further, the counter electrode 43 may be provided on a resin stand on which the power supply bus bar 50 is provided.

(Other variations)
In this embodiment, the assembled battery 10 showed the example which has five battery cells. However, the assembled battery 10 should just have two or more battery cells, and is not limited to the said example.

  In this embodiment, the assembled battery 10 has shown the example which has two battery stacks. However, the number of battery stacks may be one or three or more instead of two.

  In the present embodiment, an example is shown in which the battery cells of the battery stack are arranged in the height direction. However, the direction in which the battery cells are arranged is not particularly limited, and may be arranged in the vertical direction or the horizontal direction.

  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.

DESCRIPTION OF SYMBOLS 10 ... Assembly battery, 10g ... Positive electrode terminal, 10h ... Negative electrode terminal, 11 ... 1st battery cell, 12 ... 2nd battery cell, 13 ... 3rd battery cell, 14 ... 4th battery cell, 15 ... 5th battery cell, 22 ... BMU, 27 ... determination circuit, 28 ... output circuit, 29 ... determination circuit, 41a ... first voltage wiring, 41b ... second voltage wiring, 41c ... third voltage wiring, 41d ... fourth voltage wiring, 41e ... first 5 voltage wiring, 41f ... 6th voltage wiring, 42 ... submergence sensor, 43 ... counter electrode, 44 ... connection wiring, 45 ... first connector, 60 ... module case, 61 ... battery case, 62 ... wiring case, 71 ... first 1 connection bus bar, 71a ... extended portion, 81 ... housing, 83 ... bottom wall, 83a ... bottom surface, 84 ... side wall, 100 ... battery pack

Claims (7)

A plurality of battery cells (11-15);
A housing (81) for housing a plurality of the battery cells;
A detection unit (27, 42) for detecting a conductive liquid in the housing,
The said detection part is a battery pack which has a counter electrode (43) facing a ground member (71, 81, 83, 84) connected to the ground potential in the said housing | casing. The detection unit includes an output circuit (28) in which an output voltage changes due to a resistance change between the ground member and the counter electrode, and the liquid is in the casing when the output voltage exceeds a threshold voltage. A determination circuit (29) for determining
2. The facing interval between the ground member and the counter electrode is set so that the output voltage when the ground member and the counter electrode are conducted through the liquid is equal to or higher than the threshold voltage. The battery pack described in 1. The plurality of battery cells are electrically connected in series, and the electrode terminal (10h) of the battery cell (11) having the lowest potential among the plurality of battery cells electrically connected in series is connected to the ground potential. Having a plate (71),
The battery pack according to claim 1, wherein the electrode plate is included in the ground member. The housing includes a bottom wall (83), and a side wall (84) that rises annularly from the bottom surface (83a) of the bottom wall,
Each of the counter electrode and the electrode plate is surrounded by the side wall while being separated from the bottom surface,
The electrode plate has an extended portion (71a) partially extended on the bottom surface side,
The battery pack according to claim 3, wherein the counter electrode faces the extension portion. The housing is conductive and is at ground potential,
The battery pack according to claim 1, wherein the ground member includes the housing. A plurality of voltage detection lines (41a to 41f) for detecting voltages of the plurality of battery cells;
A connection wiring (44) connected to the counter electrode;
The battery pack according to any one of claims 1 to 5, further comprising: a plurality of voltage detection lines and a connector (45) that brings together the connection wirings. An insulating module case (60) for housing a plurality of the battery cells;
Each of the module case and the detection unit is housed in the housing,
The battery pack according to claim 6, wherein the module case is provided with a plurality of the voltage detection lines together with the counter electrode.

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