Battery system

Abstract

To improve detection accuracy in a case where a cell has an abnormality.SOLUTION: A battery system 1 comprises a plurality of cells 10, a hermetic pack case 20, a first abnormality detection sensor 30, a second abnormality detection sensor 40, and a controller 50. The plurality of cells 10 have a hermetic cell case 11. The cell case 11 has a first pressure valve 12 which is irreversibly broken by predetermined working pressure. The controller 50 performs an abnormality determination process for determining that an abnormality has been caused at least in one cell 10 of the plurality of cells 10 if a pressure value detected by the first abnormality detection sensor 30 is higher than a predetermined threshold Th1, and also if a detection value detected by the second abnormality detection sensor 40 is higher than a predetermined threshold Th2.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a battery system. [Background technology]

[0002] JP2022-518720A discloses a vehicle battery fire detection device including a battery pack mounted on a vehicle structure, an electronic control device, and a communication means. The battery pack includes a battery module, a battery management system, and a battery pack case. The battery management system transmits a signal received from the battery module to the electronic control device. The battery pack case includes a gas exhaust section from which venting gas is discharged. The battery pack case includes a sensor that measures at least one of the temperature and pressure of the gas discharged from the gas exhaust section. According to the vehicle battery fire detection device, when a fire occurs inside the battery pack, it is possible to detect the fire and notify the passengers.

[0003] JP2023-522766A discloses a battery system including a battery pack, a pressure sensor, and a battery management system. The battery pack includes a plurality of battery cells. The pressure sensor measures the internal pressure of the battery pack for each sampling period. The battery management system calculates a reference pressure based on the internal pressure measured for each sampling period. The battery management system calculates a pressure fluctuation amount by the difference between the internal pressure measured for each sampling period and the reference pressure. The battery management system determines that a thermal event has occurred in the battery pack when the pressure fluctuation amount is equal to or greater than a predetermined critical pressure and the internal pressure measured for each sampling period increases at least twice in succession. It is said that such a battery system can detect a thermal event in the battery. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2022-518720 [Patent Document 2] Special Publication No. 2023-522766 Summary of the Invention [Problem to be solved by the invention]

[0005] The present inventors wish to improve the accuracy of detection when an abnormality occurs in a cell. [Means for solving the problem]

[0006] The battery system disclosed herein includes a plurality of cells, a sealed pack case, a first anomaly detection sensor, a second anomaly detection sensor, and a controller. The pack case houses the plurality of cells. The first anomaly detection sensor is disposed inside the pack case. The second anomaly detection sensor is disposed inside the pack case. The plurality of cells include an electrode body and a sealed cell case housing the electrode body. The cell case has a first pressure valve configured to be irreversibly broken by a predetermined operating pressure. The pack case has a second pressure valve that is released at a predetermined pressure. The first anomaly detection sensor is a sensor that detects a pressure value in the pack case. The second anomaly detection sensor is a sensor that detects at least one detection value of a pressure value, a temperature, and a generated gas in the pack case. The controller is configured to execute an anomaly determination process that determines that an abnormality has occurred in at least one of the plurality of cells when the pressure value detected by the first anomaly detection sensor is higher than a predetermined threshold value and the detection value detected by the second anomaly detection sensor is higher than a predetermined threshold value. In such a battery system, when an abnormality occurs in a cell, the detection accuracy is good. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram showing a battery system 1. As shown in FIG. [Diagram 2] FIG. 2 is a flowchart showing the processing executed in the controller 50. [Diagram 3] FIG. 3 is a schematic diagram showing a battery system 1A according to another embodiment. [Figure 4] FIG. 4 is a flowchart showing the process executed in the controller 50 of the battery system 1A. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the technology disclosed herein will be described with reference to the drawings. The embodiment described herein is, of course, not intended to limit the present invention in particular. Each drawing is drawn typically and does not necessarily reflect the actual product. Furthermore, the same reference numerals are appropriately used for members and parts that perform the same function, and duplicated descriptions are appropriately omitted.

[0009] <Battery System 1> FIG. 1 is a schematic diagram showing a battery system 1. The battery system 1 is an assembly, also called a battery pack, that includes batteries (cells), a configuration for controlling the cells, safety devices, and the like. As shown in FIG. 1, the battery system 1 includes a plurality of cells 10, a pack case 20, a first abnormality detection sensor 30, a second abnormality detection sensor 40, and a controller 50. The battery system 1 also includes a contactor unit 15. The pack case 20 is of a sealed type and houses the plurality of cells 10. The first abnormality detection sensor 30 and the second abnormality detection sensor 40 are disposed inside the pack case 20.

[0010] The battery system 1 is connected in series to a load 60 via an external output terminal (not shown) provided on a surface 25 of the pack case 20. In this embodiment, the battery system 1 is connected to the load 60 of an electric vehicle. Although not limited to this, the load 60 may be constituted by, for example, an electric motor, an inverter, etc. of the vehicle. Power is supplied to the load 60 from the multiple cells 10 of the battery system 1. Note that the load 60 is not limited to this form, and the battery system 1 can be applied to systems other than a battery system mounted on an electric vehicle.

[0011] <Multiple Cells 10> The plurality of cells 10 each have an electrode body (not shown) and a sealed cell case 11. The cell 10 is an electricity storage device capable of extracting electric energy. The cell 10 includes a secondary battery capable of repeated charging and discharging by the movement of charge carriers between a pair of electrodes (positive and negative electrodes) via an electrolyte, and includes, for example, a lithium ion secondary battery, a nickel-metal hydride battery, and the like. The connection form of the plurality of cells 10 is not particularly limited. The plurality of cells 10 are electrically connected to each other via a bus bar, and constitute a cell module (battery assembly) 10A. The plurality of cells 10 may be connected in series, in parallel, or in a combination of series and parallel. In this embodiment, the plurality of cells 10 are connected in series.

[0012] The sealed cell case 11 houses the electrode body. The cell case 11 is a container having a substantially rectangular parallelepiped shape. The cell case 11 can be made of aluminum or an aluminum alloy from the viewpoint of weight reduction and securing the required rigidity. The cell case 11 has a first pressure valve 12. The first pressure valve 12 is configured to break irreversibly at a predetermined operating pressure. The operating pressure of the first pressure valve 12 is not particularly limited and can be set appropriately depending on the configuration of the cell 10, the use conditions, and the like. The first pressure valve 12 can function as a safety device that breaks when the inside of the cell case 11 reaches a predetermined operating pressure in the case where an abnormality occurs in the cell 10 and a large amount of gas is suddenly generated in the cell case 11. This allows the gas generated in the cell case 11 to be released to the outside. The first pressure valve 12 is also called a safety valve. In this embodiment, the multiple cells 10 are housed in the pack case 20 with their orientations aligned. The first pressure valves 12 provided in each of the multiple cells 10 are oriented in the same direction (downward in FIG. 1) within the pack case 20.

[0013] The multiple cells 10 (cell module 10A) are connected to a load 60 via external output terminals and supply power to the load 60. Between the multiple cells 10 and the load 60, a contactor unit 15 is provided.

[0014] <Contactor unit 15> The contactor unit 15 switches the connection between the cell module 10A and the load 60. The contactor unit 15 includes a pre-charge circuit 16 and main relays 17 and 18. The pre-charge circuit 16 and the main relay 17 are connected to the positive electrode side of the cell module 10A. The pre-charge circuit 16 and the main relay 17 are connected in parallel. The main relay 18 is connected to the negative electrode side of the cell module 10A.

[0015] The precharge circuit 16 is a circuit in which a precharge resistor 16a and a precharge relay 16b are connected in series. The precharge circuit 16 is a circuit that prevents an inrush current from flowing to the load 60 when power is supplied from the battery system 1 to the load 60. Before the load 60 is started, the main relays 17 and 18 and the precharge relay 16b are opened. When the battery system 1 connected to the load 60 is started, the main relay 18 and the precharge relay 16b are switched to a closed state. The load 60 is connected to the battery system 1 via the precharge circuit 16. At this time, since the precharge resistor 16a is provided in the precharge circuit 16, power is supplied to the load 60 from the cell module 10A at a low current. After that, the main relay 17 is closed when the potential of the load 60 is increased, and then the precharge relay 16b is opened. This prevents a large current from flowing to the load 60. The opening and closing of the main relays 17, 18 and the pre-charge relay 16b is controlled by a later-described controller 50. In this embodiment, the contactor unit 15 is provided in the pack case 20, similar to the cell module 10A.

[0016] Pack Case 20 The pack case 20 is a sealed container that houses a plurality of cells 10 and the like. The pack case 20 has a substantially rectangular parallelepiped shape. The pack case 20 can be made of aluminum or an aluminum alloy from the viewpoint of weight reduction and ensuring the required rigidity. The pack case 20 has a second pressure valve 22 that is released at a predetermined pressure. The second pressure valve 22 is different from the first pressure valve 12 provided in the cell 10, and is configured to adjust the internal pressure when the internal pressure increases. After the internal pressure of the pack case 20 is adjusted, the second pressure valve 22 is closed and the inside of the pack case 20 is sealed again. The operating pressure of the second pressure valve 22 is not particularly limited and can be appropriately set depending on the configuration of the battery system 1, the use conditions, and the like.

[0017] The second pressure valve 22 is provided at a position not facing the first pressure valves 12 provided in the multiple cells 10. By providing the second pressure valve 22 at a position not facing the first pressure valve 12, damage to the second pressure valve 22 due to operation of the first pressure valve 12 is suppressed. In this embodiment, the second pressure valve 22 is provided on a surface 23 facing the first pressure valve 12, at a position 23a not facing the first pressure valve 12. The second pressure valve 22 may be provided on other surfaces 24 to 26 of the pack case 20.

[0018] In the battery system 1 in which a plurality of cells 10 are housed in a sealed pack case 20, an abnormality may occur in a cell 10 due to an unexpected external impact or the like. At this time, various reactions may occur in the cell case 11 of the abnormal cell 10, and gas may be generated. This causes the pressure in the cell case 11 to rise. When the pressure in the cell case 11 reaches a predetermined operating pressure, the first pressure valve 12 breaks irreversibly. As a result, gas is released into the pack case 20. This may cause the pressure in the pack case 20 to rise. In addition, when an abnormality occurs in a cell 10, there is a concern that the temperature of the cell 10 may rise.

[0019] In the battery system 1, a first abnormality detection sensor 30 and a second abnormality detection sensor 40 are housed inside the pack case 20 together with the cell module 10A.

[0020] <First abnormality detection sensor 30> The first abnormality detection sensor 30 is a sensor that detects the pressure value inside the pack case 20. The first abnormality detection sensor 30 is configured to be able to detect, for example, the pressure value of the gas inside the pack case 20 and output it to the controller 50. The first abnormality detection sensor 30 is not particularly limited as long as it can detect the pressure value of the gas inside the pack case 20. The first abnormality detection sensor 30 can be disposed at a position (position 23a in this embodiment) that does not face the first pressure valve 12. This makes it easier to stably detect the pressure value when the first pressure valve 12 is activated, without being affected by the pressure value that may change locally in a short time.

[0021] A plurality of first anomaly detection sensors 30 may be provided inside the pack case 20. When a plurality of first anomaly detection sensors 30 are provided, the first anomaly detection sensors 30 can be arranged so as to detect pressure values ​​at different positions inside the pack case 20. This makes it easy to detect pressure abnormalities occurring inside the pack case 20 even when the pack case 20 is large.

[0022] <Second abnormality detection sensor 40> The second abnormality detection sensor 40 is a sensor that detects at least one of the pressure value, temperature, and generated gas in the pack case 20. A sensor that can detect an abnormality according to the components or state of the gas in the pack case 20 can be used as the second abnormality detection sensor 40. In this embodiment, the second abnormality detection sensor 40 is a sensor that detects the pressure value in the pack case 20, similar to the first abnormality detection sensor 30. The second abnormality detection sensor 40 can be disposed at a position that does not face the first pressure valve 12. The second abnormality detection sensor 40 is configured to detect the pressure value of the gas in the pack case 20 and output it to the controller 50. The configuration of the second abnormality detection sensor 40 can be the same as that of the first abnormality detection sensor 30, and therefore a detailed description thereof will be omitted.

[0023] <Controller 50> The controller 50 is configured to execute an abnormality determination process for determining whether or not an abnormality occurs in at least one of the multiple cells 10. The controller 50 also controls the contactor unit 15, and controls the connection and disconnection between the load 60 and the multiple cells 10. The controller 50 may be supplied with power from a power source 80 provided outside the pack case 20. The controller 50 includes a first acquisition unit 51, a second acquisition unit 52, a communication unit 53, a determination unit 54, and an instruction unit 55. Each unit 51 to 55 of the controller 50 may be realized by one or more processors, or may be incorporated into a circuit. The controller 50 is connected to a host controller 70 provided outside the pack case 20 via the communication unit 53 so as to be able to communicate with the host controller 70.

[0024] The upper controller 70 controls the controller 50, which controls the connection and disconnection between the load 60 and the multiple cells 10. The upper controller 70 is communicably connected to the controller 50. The upper controller 70 may be, for example, an in-vehicle ECU (Electronic Control Unit). In this embodiment, whether or not an abnormality has occurred in the cell 10 is determined by the controller 50. The process executed by the controller 50 to determine whether or not an abnormality has occurred in the cell 10 will be described below.

[0025] In this embodiment, the pressure values ​​detected by the first abnormality detection sensor 30 and the second abnormality detection sensor 40 are notified to the controller 50. The first abnormality detection sensor 30 and the second abnormality detection sensor 40 can detect pressure values ​​at predetermined intervals and notify the controller 50. The detection and notification intervals are not particularly limited, but can be set to about 0.1 to 1 second, for example.

[0026] When the pressure values ​​detected by the first anomaly detection sensor 30 and the second anomaly detection sensor 40 are notified to the controller 50, the controller 50 executes an anomaly determination process to determine whether or not an anomaly has occurred in the cell 10.

[0027] 2 is a flowchart showing a process executed by the controller 50. The controller 50 is set with thresholds Th1 and Th2 of the pressure values ​​notified from the first abnormality detection sensor 30 and the second abnormality detection sensor 40. In this embodiment, the threshold Th1 of the pressure value detected by the first abnormality detection sensor 30 is set to a value higher than the atmospheric pressure and lower than the operating pressure at which the second pressure valve 22 operates. The threshold Th2 of the pressure value detected by the second abnormality detection sensor 40 is set to the same value as the threshold of the pressure value detected by the first abnormality detection sensor 30. Note that the thresholds Th1 and Th2 detected by the first abnormality detection sensor 30 and the second abnormality detection sensor 40 may be different values.

[0028] When the controller 50 is started, an abnormality determination process is started. The abnormality determination process can be executed at any time when the battery system 1 is started. In step S10 of FIG. 2, the first acquisition unit 51 of the controller 50 acquires a pressure value (hereinafter also referred to as "first pressure value P1") detected by the first abnormality detection sensor 30. The determination unit 54 determines whether or not the first pressure value P1 is equal to or less than a threshold value Th1. If the first pressure value P1 is equal to or less than the threshold value Th1 (YES), the process proceeds to step S30.

[0029] In step S30 of FIG. 2, the second acquisition unit 52 of the controller 50 acquires a pressure value (hereinafter also referred to as "second pressure value P2") detected by the second abnormality detection sensor 40. The determination unit 54 determines whether the second pressure value P2 is equal to or less than the threshold value Th2. If the second pressure value P2 is equal to or less than the threshold value Th2 (YES), it is determined that the multiple cells 10 in the pack case 20 are normal. Note that if the battery system 1 is activated, the abnormality determination process is started again. The abnormality determination process can be executed until the battery system 1 is stopped.

[0030] In step S10 of Fig. 2, if the first pressure value P1 is higher than the threshold value Th1 (NO), the process proceeds to step S20. In step S20 of Fig. 2, similar to step S30, it is determined whether the second pressure value P2 is equal to or lower than the threshold value Th2. As with the first pressure value P1, if the second pressure value P2 is higher than the threshold value Th2 (NO), it is determined that an abnormality has occurred in at least one of the multiple cells 10 in the pack case 20.

[0031] Thus, in the battery system 1, the controller 50 determines that an abnormality has occurred in at least one of the multiple cells 10 when the first pressure value P1 detected by the first abnormality detection sensor 30 is higher than the predetermined threshold value Th1 and the detection value detected by the second abnormality detection sensor 40 (in this embodiment, the second pressure value P2) is higher than the predetermined threshold value Th2.

[0032] In the above-described embodiment, the battery system 1 includes a first abnormality detection sensor 30 that detects a pressure value in the pack case 20. This makes it possible to detect an increase in the pressure value in the pack case 20 due to gas released from the abnormal cell 10 when an abnormality occurs in any of the multiple cells 10. Furthermore, the battery system 1 includes a second abnormality detection sensor 40. This makes it possible to detect an abnormality more accurately. When it is determined that an abnormality occurs in the cell 10 of the battery system 1, the controller 50 can notify the upper controller 70 that an abnormality occurs in the cell 10. The upper controller 70 can notify a user that an abnormality occurs in the cell 10. The user can recognize that an abnormality occurs in the cell 10 of the battery system 1, and can take appropriate measures such as inspection and repair.

[0033] In the above-described embodiment, the threshold value Th1 of the first pressure value P1 detected by the first anomaly detection sensor 30 is set to a value higher than atmospheric pressure and lower than the operating pressure at which the second pressure valve 22 operates. This makes it easier to detect an abnormality in the cell 10 at a stage before the second pressure valve 22 operates and the gas in the pack is released.

[0034] In the above-described embodiment, the second anomaly detection sensor 40 is a sensor that detects the pressure value inside the pack case 20. The second anomaly detection sensor 40 detects the pressure value inside the pack case 20, just like the first anomaly detection sensor 30. Because the first anomaly detection sensor 30 and the second anomaly detection sensor 40 use the same detection value as an index to determine an abnormality in the cell 10, there is little risk of a discrepancy in the determination conditions between the sensors. This makes it possible to detect an abnormality in the cell 10 more accurately and quickly.

[0035] In the battery system 1, when an abnormality in a cell 10 is detected, the load 60 may be disconnected from the multiple cells 10 to ensure safety. In this embodiment, the controller 50 is configured to execute a process of controlling the contactor unit 15 to an open state when an abnormality in a cell 10 is detected in the abnormality determination process. When the determination unit 54 of the controller 50 determines that an abnormality has occurred in a cell 10, the instruction unit 55 controls the contactor unit 15 to an open state. In this embodiment, at least one of the main relays 17 and 18 is controlled to an open state. By cutting off the connection to the load 60 when an abnormality occurs in a cell 10, safety can be improved.

[0036] Note that the battery system 1 may be provided with a mechanism for determining whether or not either the first abnormality detection sensor 30 or the second abnormality detection sensor 40 has a malfunction. In this embodiment, the controller 50 is configured to execute a malfunction determination process for determining whether or not either the first abnormality detection sensor 30 or the second abnormality detection sensor 40 has a malfunction.

[0037] After it is determined in step S10 that the first pressure value P1 is higher than the threshold value Th1 (NO), if it is determined in step S20 that the second pressure value P2 is equal to or lower than the threshold value Th2 (YES), the process proceeds to step S25. In step S25 of FIG. 2, it is determined whether or not the elapsed time t2 since it was determined in step S20 that the second pressure value P2 is equal to or lower than the threshold value Th2 exceeds a predetermined time T2. The predetermined time T2 can be determined in advance to be long enough to detect an abnormality in the sensor, and within a range in which the abnormality in the sensor does not interfere with the operation of the battery system 1.

[0038] In step S25, if the elapsed time t2 does not exceed the predetermined time T2 (NO), the process returns to step S20. The process of determining whether the second pressure value P2 is equal to or less than the threshold value Th2 is executed again. Here, if it is determined in step S20 that the second pressure value P2 is higher than the threshold value Th2 (NO), it is determined that both the first pressure value P1 and the second pressure value P2 are higher than the threshold values ​​Th1 and Th2. Therefore, as described above, it is determined that an abnormality has occurred in the cell 10 of the battery system 1.

[0039] In step S25, if the elapsed time t2 exceeds the predetermined time T2 (YES), the first pressure value P1 has been higher than the threshold value Th1 and the second pressure value P2 has been equal to or lower than the threshold value Th2 for a certain period of time. In this case, the first abnormality detection sensor 30 and the second abnormality detection sensor 40 make different judgments. Here, although the second pressure value P2 is equal to or lower than the threshold value Th2 for the predetermined period of time T2, the first pressure value P1 is higher than the threshold value Th1. The judgment unit 54 judges that the first abnormality detection sensor 30 is broken. The communication unit 53 of the controller 50 notifies the upper controller 70 that the first abnormality detection sensor 30 may be broken. The user can recognize that an abnormality has occurred in the first abnormality detection sensor 30 of the battery system 1, and can take appropriate measures such as inspection and repair.

[0040] After it is determined in step S30 that the second pressure value P2 is higher than the threshold value Th2 (NO), in step S40 in FIG. 2, it is determined whether the first pressure value P1 is equal to or lower than the threshold value Th1, as in step S10. If the first pressure value P1 is higher than the threshold value Th1 (NO), it is determined that both the first pressure value P1 and the second pressure value P2 are higher than the threshold values ​​Th1 and Th2. Therefore, it is determined that an abnormality has occurred in at least one cell 10 among the multiple cells 10 in the pack case 20. If the first pressure value P1 is equal to or lower than the threshold value Th1 in step S40 (YES), the process proceeds to step S45. In step S45 in FIG. 2, it is determined whether the elapsed time t1 from when it is determined in step S40 that the first pressure value P1 is equal to or lower than the threshold value Th1 has exceeded a predetermined time T1. The predetermined time T1 may be the same as or different from the predetermined time T2 described above.

[0041] In step S45, if the elapsed time t1 does not exceed the predetermined time T1 (NO), the process returns to step S40, and a process of determining whether the first pressure value P1 is equal to or less than the threshold value Th1 is executed. If it is determined that the first pressure value P1 is higher than the threshold value Th1, it is determined that an abnormality has occurred in the cell 10 of the battery system 1.

[0042] In step S45, if the elapsed time t1 exceeds the predetermined time T1 (YES), the second pressure value P2 has been higher than the threshold value Th2 and the first pressure value P1 has been equal to or lower than the threshold value Th1 for a certain period of time. In this case, the first abnormality detection sensor 30 and the second abnormality detection sensor 40 make different judgments. Here, although the first pressure value P1 is equal to or lower than the threshold value Th1 for the certain period of time T1, the second pressure value P2 is higher than the threshold value Th2. The judgment unit 54 judges that the second abnormality detection sensor 40 is broken. The communication unit 53 of the controller 50 notifies the upper controller 70 that the second abnormality detection sensor 40 may be broken. The user can recognize that an abnormality has occurred in the second abnormality detection sensor 40 of the battery system 1, and can take appropriate measures such as inspection and repair.

[0043] In this way, in the battery system 1, if a predetermined time T1, T2 has elapsed in a state where one of the first pressure value P1 detected by the first abnormality detection sensor 30 and the detection value detected by the second abnormality detection sensor 40 (in this embodiment, the second pressure value P2) is higher than a predetermined threshold and the other is equal to or lower than the predetermined threshold, it is determined that either the first abnormality detection sensor 30 or the second abnormality detection sensor 40 has failed.

[0044] The battery system 1 may be configured to be switchable between a low power consumption mode in which power consumption is reduced and a normal mode in which power is supplied to the load 60. For example, when the battery system 1 is used as an on-board battery, it may be switched to the power saving mode when the power supply of the electric vehicle is turned off, and to the normal mode when the electric vehicle is in operation. In addition, it may be switched to the normal mode when the battery system 1 is being charged.

[0045] In this embodiment, the controller 50 is configured to switch between a low power consumption mode and a normal mode. In the normal mode, the above-mentioned process is executed, and a process for detecting an abnormality in the cell 10 included in the battery system 1 is executed. In the low power consumption mode, a process different from the above may be executed. For example, in order to reduce power consumption, the above-mentioned process such as the abnormality detection process may be stopped.

[0046] In this embodiment, even in the low power consumption mode, a process for detecting an abnormality in the cell 10 at an early stage is executed. Here, the first acquisition unit 51 and the second acquisition unit 52 of the controller 50 acquire a pressure value (first pressure value P1) detected by the first abnormality detection sensor 30 and a detection value (second pressure value P2) detected by the second abnormality detection sensor 40. The determination unit 54 determines whether or not at least one of the pressure value detected by the first abnormality detection sensor 30 and the detection value detected by the second abnormality detection sensor 40 is higher than a predetermined threshold value. Here, it is determined whether or not the first pressure value P1 is higher than the threshold value Th1, and it is determined whether or not the second pressure value P2 is higher than the threshold value Th2. When at least one of the first pressure value P1 and the second pressure value P2 is higher than the threshold value, the instruction unit 55 instructs switching from the low power consumption mode to the normal mode. When the battery system 1 switches from the low power consumption mode to the normal mode, the abnormality detection process described above is executed. This allows early detection of an abnormality in the cell 10 that may occur after the transition to the low power consumption mode.

[0047] In this embodiment, the first anomaly detection sensor 30 and the second anomaly detection sensor 40 are provided, and it is possible to check whether or not they are operating normally by the control of the controller 50. However, without being limited to such a form, the battery system 1 may be provided with a self-diagnosis function for checking whether or not the first anomaly detection sensor 30 itself is operating normally. The self-diagnosis function may be provided in the first anomaly detection sensor 30, or may be configured to cooperate with the controller 50. By providing the self-diagnosis function, an abnormality in the cell 10 may be detected without using the second anomaly detection sensor 40. This allows the battery system 1 to be made space-saving.

[0048] In the above-described embodiment, the second abnormality detection sensor 40 is a sensor that detects a pressure value inside the pack case 20. However, the second abnormality detection sensor 40 is not limited to this form.

[0049] For example, the second abnormality detection sensor 40 may be a sensor that detects the temperature inside the pack case 20. When a temperature sensor is used as the second abnormality detection sensor 40, the second abnormality detection sensor 40 may be disposed, for example, in a path of the gas discharged from the first pressure valve 12 when an abnormality occurs in the cell 10. The second abnormality detection sensor 40 detects the temperature of the high-temperature gas discharged from the cell 10, so that an abnormality in the cell 10 can be detected early. Note that the threshold value for determining an abnormality in the cell 10 according to the detection value (temperature) of the temperature sensor may be appropriately determined according to the configuration, specifications, etc. of the cell 10.

[0050] The second abnormality detection sensor 40 may be a sensor that detects the gas generated in the pack case 20. When a gas sensor is used as the second abnormality detection sensor 40, the second abnormality detection sensor 40 may be disposed, for example, in a path of the gas discharged from the first pressure valve 12 when an abnormality occurs in the cell 10. The second abnormality detection sensor 40 detects a predetermined gas discharged from the cell 10, so that an abnormality in the cell 10 can be detected early. When a gas sensor is used as the second abnormality detection sensor 40, a threshold value for determining an abnormality in the cell 10 may be determined based on the gas components and concentration. Although not particularly limited, examples of the gas components that the gas sensor detects include carbon dioxide and hydrocarbons. The gas components and gas concentrations that the gas sensor detects may be appropriately determined according to the configuration, specifications, and the like of the cell 10. The gas sensor may be a sensor that detects smoke.

[0051] The second abnormality detection sensor may be a sensor that detects a voltage value of a cell in the pack case. Fig. 3 is a schematic diagram showing a battery system 1A according to another embodiment. In the description of the battery system 1A shown in Fig. 3, the same reference numerals are appropriately used for members and parts having the same functions, and duplicated descriptions are appropriately omitted.

[0052] <Battery System 1A> As shown in Fig. 3, the battery system 1A includes a plurality of cells 10, a pack case 20, a first abnormality detection sensor 30, a second abnormality detection sensor 40A, and a controller 50. The first abnormality detection sensor 30 and the second abnormality detection sensor 40A are disposed inside the pack case 20. The battery system 1A may have the same configuration as the battery system 1 (see Fig. 1) except that the second abnormality detection sensor 40A is used instead of the second abnormality detection sensor 40 (see Fig. 1).

[0053] <Second abnormality detection sensor 40A> The second abnormality detection sensor 40A is a sensor that detects at least one detection value among the pressure value, temperature, and generated gas inside the pack case 20, and the voltage of the cell 10. The second abnormality detection sensor 40A may be similar to the second abnormality detection sensor 40 (see FIG. 1) except that it is configured to detect the voltage value of the cell 10. A voltage sensor may be used as the second abnormality detection sensor 40A. The second abnormality detection sensor 40A may be composed of multiple sensors or may be composed of one sensor (for example, a voltage sensor). The second abnormality detection sensor 40A may be configured by combining a sensor that detects at least one detection value among the pressure value, temperature, and generated gas with a voltage sensor.

[0054] In this embodiment, the second abnormality detection sensor 40A is a sensor that detects the voltage of the cell 10. Here, the "voltage of the cell 10" refers to the voltage of at least one of the multiple cells. The second abnormality detection sensor 40A may detect the voltage value of each cell 10. The second abnormality detection sensor 40A may detect the voltage value of one or more of the multiple cells 10, or may detect the voltage value of all of the multiple cells 10 (so-called total voltage). In this embodiment, the second abnormality detection sensor 40A detects the voltage value of each cell 10. The voltage value detected by the second abnormality detection sensor 40A is transmitted to the controller 50.

[0055] A threshold value for the voltage value transmitted from the second anomaly detection sensor 40A is set in the controller 50. When the voltage value detected by the second anomaly detection sensor 40A is lower than the predetermined threshold value, the controller 50 determines that an abnormality has occurred in at least one of the multiple cells 10.

[0056] The threshold value may vary depending on the characteristics of the cells 10 used in the battery system 1A. For this reason, the threshold value may be determined after verifying the voltage characteristics of the cells 10 in advance by testing or the like. According to trials by the present inventor, when an abnormality occurs in any one of the multiple cells 10, a phenomenon has been confirmed in which the voltage of the abnormal cell 10 also drops suddenly when gas is released from the abnormal cell 10. The voltage value threshold value may be set to, for example, the end voltage of the cell 10.

[0057] Fig. 4 is a flowchart showing the process executed by the controller 50 of the battery system 1A. In Fig. 4, the process is the same as that shown in Fig. 2 except that the determinations of steps S21 and S31 are executed instead of steps S20 and S30 in Fig. 2, and therefore duplicated explanations will be omitted where appropriate.

[0058] If it is determined in step S10 that the first pressure value P1 is equal to or less than the threshold value Th1 (YES), the process proceeds to step S31 in FIG. 4. In step S31, it is determined whether or not the voltage value V is equal to or greater than the threshold value Vth. If the voltage value V is equal to or greater than the threshold value Vth (YES), the multiple cells 10 in the pack case 20 are determined to be normal. If it is determined in step S31 that the voltage value V is lower than the threshold value Vth (NO), the process proceeds to step S40. After step S40, the same process as that described in FIG. 2 may be executed.

[0059] If it is determined in step S10 that the first pressure value P1 is higher than the threshold value Th1 (NO), the process proceeds to step S21 in FIG. 4. In step S21, it is determined whether or not the voltage value V is equal to or higher than the threshold value Vth. If the voltage value V is lower than the threshold value Vth (NO), it is determined that an abnormality has occurred in at least one of the multiple cells 10 in the pack case 20. If it is determined in step S21 that the voltage value V is equal to or higher than the threshold value Vth (YES), the process proceeds to step S25. After step S25, the same process as that described in FIG. 2 may be executed.

[0060] By using the second abnormality detection sensor 40A that detects the voltage of the cell 10, the phenomenon of a drop in the voltage value of the cell 10 can be detected in addition to the increase in the pressure value inside the pack case 20. This allows for early detection of an abnormality in the cell 10. Furthermore, if the second abnormality detection sensor 40A can detect the voltage value of each of the multiple cells 10, it can detect which cell 10 in the pack case 20 has become abnormal. As a result, it is easy to take measures after an abnormality occurs.

[0061] The battery system disclosed herein includes a plurality of cells, a sealed pack case, a first anomaly detection sensor, a second anomaly detection sensor, and a controller. The pack case houses the plurality of cells. The first anomaly detection sensor is disposed inside the pack case. The second anomaly detection sensor is disposed inside the pack case. The plurality of cells includes an electrode body and a sealed cell case housing the electrode body. The cell case includes a first pressure valve configured to be irreversibly broken by a predetermined operating pressure. The pack case includes a second pressure valve that is released at a predetermined pressure. The first anomaly detection sensor is a sensor that detects a pressure value in the pack case. The second anomaly detection sensor is a sensor that detects at least one of the detection values ​​of the pressure value, temperature, and generated gas in the pack case, and the voltage value of at least one of the plurality of cells. When the second abnormality detection sensor is a sensor that detects at least one of the pressure value, temperature, and generated gas in the pack case, the controller is configured to execute an abnormality determination process to determine that an abnormality has occurred in at least one of the multiple cells when the pressure value detected by the first abnormality detection sensor is higher than a predetermined threshold value and the detection value detected by the second abnormality detection sensor is higher than a predetermined threshold value. When the second abnormality detection sensor is a sensor that detects the voltage value of at least one of the multiple cells, the controller is configured to execute an abnormality determination process to determine that an abnormality has occurred in at least one of the multiple cells when the pressure value detected by the first abnormality detection sensor is higher than a predetermined threshold value and the voltage value detected by the second abnormality detection sensor is lower than a predetermined threshold value. In such a battery system, the detection accuracy when an abnormality occurs in a cell is good.

[0062] The technology disclosed herein has been described above in various ways. Unless otherwise specified, the embodiments and the like described herein do not limit the present invention. Furthermore, the technology disclosed herein can be modified in various ways, and each component and each process described herein can be omitted or combined as appropriate unless a particular problem occurs. Furthermore, this specification includes the disclosures described in the following sections.

[0063] Section 1: A plurality of cells; a sealed pack case that houses the plurality of cells; A first abnormality detection sensor disposed inside the pack case; A second abnormality detection sensor disposed inside the pack case; Controller and Equipped with The plurality of cells each include an electrode assembly and a sealed cell case that houses the electrode assembly, the cell casing having a first pressure valve configured to irreversibly rupture at a predetermined actuation pressure; the pack case has a second pressure valve that is released at a predetermined pressure; the first abnormality detection sensor is a sensor that detects a pressure value inside the pack case, the second abnormality detection sensor is a sensor that detects at least one of a pressure value, a temperature, and a generated gas value inside the pack case, The controller is configured to execute an abnormality determination process to determine that an abnormality has occurred in at least one of the multiple cells when the pressure value detected by the first abnormality detection sensor is higher than a predetermined threshold value and the detection value detected by the second abnormality detection sensor is higher than a predetermined threshold value.

[0064] Section 2: Item 2. The battery system according to item 1, wherein the first abnormality detection sensor and the second abnormality detection sensor are arranged in a position not facing the first pressure valve.

[0065] Section 3: 3. The battery system according to item 1 or 2, wherein a threshold value of the pressure value detected by the first abnormality detection sensor is set to a value higher than atmospheric pressure and lower than an operating pressure at which the second pressure valve operates.

[0066] Section 4: The controller is configured to switch between a low power consumption mode and a normal mode; In the low power consumption mode, The controller performs a process of acquiring a pressure value detected by the first anomaly detection sensor and a detection value detected by the second anomaly detection sensor; The battery system according to any one of items 1 to 3, wherein the battery system is configured to switch from the low power consumption mode to the normal mode and execute the abnormality determination process when at least one of the pressure value detected by the first abnormality detection sensor and the detection value detected by the second abnormality detection sensor is higher than a predetermined threshold value.

[0067] Section 5: A contactor unit that switches a connection between the plurality of cells and a load, The battery system according to any one of items 1 to 4, wherein the controller is configured to execute a process of controlling the contactor unit to an open state when an abnormality in the cell is detected in the abnormality determination process.

[0068] Item 6: 6. The battery system according to any one of items 1 to 5, wherein the second abnormality detection sensor is a sensor that detects a pressure value inside the pack case.

[0069] Section 7: 6. The battery system according to any one of items 1 to 5, wherein the second abnormality detection sensor is a sensor that detects a temperature inside the pack case.

[0070] Section 8: 6. The battery system according to any one of items 1 to 5, wherein the second abnormality detection sensor is a sensor that detects gas generated inside the pack case.

[0071] Section 9: The battery system according to any one of items 1 to 8, wherein the controller is configured to execute a process of determining that either the first abnormality detection sensor or the second abnormality detection sensor is faulty when a predetermined time has elapsed in a state in which one of the pressure value detected by the first abnormality detection sensor and the detection value detected by the second abnormality detection sensor is higher than a predetermined threshold and the other is equal to or lower than a predetermined threshold.

[0072] Section 10: A plurality of cells; a sealed pack case that houses the plurality of cells; A first abnormality detection sensor disposed inside the pack case; A second abnormality detection sensor disposed inside the pack case; Controller and Equipped with The plurality of cells each include an electrode assembly and a sealed cell case that houses the electrode assembly, the cell casing having a first pressure valve configured to irreversibly rupture at a predetermined actuation pressure; the pack case has a second pressure valve that is released at a predetermined pressure; the first abnormality detection sensor is a sensor that detects a pressure value inside the pack case, the second abnormality detection sensor is a sensor that detects at least one of a pressure value, a temperature, and a generated gas inside the pack case, and a voltage value of at least one of the plurality of cells, The controller detects that the pressure value detected by the first anomaly detection sensor is higher than a predetermined threshold value, and In a case where the second abnormality detection sensor is a sensor that detects at least one of a pressure value, a temperature, and a generated gas inside the pack case, when the detection value detected by the second abnormality detection sensor is higher than a predetermined threshold value, In the case where the second abnormality detection sensor is a sensor for detecting a voltage value of at least one of the plurality of cells, when the voltage value detected by the second abnormality detection sensor is lower than a predetermined threshold value, and executing an abnormality determination process to determine that an abnormality has occurred in at least one of the plurality of cells. [Explanation of symbols]

[0073] 1,1A battery system 10 Cells 10A cell module 11 Cell Case 12 First pressure valve 15 Contactor Unit 16 Precharge Circuit 16a Precharge resistor 16b Precharge relay 17,18 Main relay 20 pack case 22 Second pressure valve 23~26 sides 23a position 30 First abnormality detection sensor 40,40A Second abnormality detection sensor 50 Controller 51 First Acquisition Department 52 Second Acquisition Department 53 Communications Department 54 Judgment section 55 Instruction section 60 Load 70 Upper controller 80 power supply P1 First pressure value P2 Second pressure value Th1, Th2 thresholds T1, T2 Predetermined time t1,t2 Elapsed time

Claims

1. A plurality of cells; a sealed pack case that houses the plurality of cells; A first abnormality detection sensor disposed inside the pack case; A second abnormality detection sensor disposed inside the pack case; Controller and Equipped with The plurality of cells each include an electrode assembly and a sealed cell case that houses the electrode assembly, the cell casing having a first pressure valve configured to irreversibly rupture at a predetermined actuation pressure; the pack case has a second pressure valve that is released at a predetermined pressure; the first abnormality detection sensor is a sensor that detects a pressure value inside the pack case, the second abnormality detection sensor is a sensor that detects at least one of a pressure value, a temperature, and a generated gas value inside the pack case, The controller is configured to execute an abnormality determination process to determine that an abnormality has occurred in at least one of the multiple cells when the pressure value detected by the first abnormality detection sensor is higher than a predetermined threshold value and the detection value detected by the second abnormality detection sensor is higher than a predetermined threshold value.

2. The battery system according to claim 1 , wherein the first abnormality detection sensor and the second abnormality detection sensor are disposed at positions not facing the first pressure valve.

3. 3 . The battery system according to claim 1 , wherein a threshold value of the pressure value detected by the first abnormality detection sensor is set to a value higher than atmospheric pressure and lower than an operating pressure at which the second pressure valve operates.

4. The controller is configured to switch between a low power consumption mode and a normal mode; In the low power consumption mode, The controller performs a process of acquiring a pressure value detected by the first anomaly detection sensor and a detection value detected by the second anomaly detection sensor; 3. The battery system of claim 1, wherein the battery system is configured to switch from the low power consumption mode to the normal mode and execute the abnormality determination process when at least one of the pressure value detected by the first abnormality detection sensor and the detection value detected by the second abnormality detection sensor is higher than a predetermined threshold value.

5. A contactor unit that switches a connection between the plurality of cells and a load, 3 . The battery system according to claim 1 , wherein the controller is configured to execute a process of controlling the contactor unit to an open state when an abnormality in the cell is detected in the abnormality determination process.

6. The battery system according to claim 1 , wherein the second abnormality detection sensor is a sensor that detects a pressure value inside the pack case.

7. The battery system according to claim 1 , wherein the second abnormality detection sensor is a sensor that detects a temperature inside the pack case.

8. 3. The battery system according to claim 1, wherein the second abnormality detection sensor is a sensor that detects gas generated in the pack case.

9. 3. The battery system of claim 1, wherein the controller is configured to execute a process of determining that either the first anomaly detection sensor or the second anomaly detection sensor has failed when a predetermined time has elapsed in a state in which one of the pressure value detected by the first anomaly detection sensor and the detection value detected by the second anomaly detection sensor is higher than a predetermined threshold and the other is equal to or lower than a predetermined threshold.

10. A plurality of cells; a sealed pack case that houses the plurality of cells; A first abnormality detection sensor disposed inside the pack case; A second abnormality detection sensor disposed inside the pack case; Controller and Equipped with The plurality of cells each include an electrode assembly and a sealed cell case that houses the electrode assembly, the cell casing having a first pressure valve configured to irreversibly rupture at a predetermined actuation pressure; the pack case has a second pressure valve that is released at a predetermined pressure; the first abnormality detection sensor is a sensor that detects a pressure value inside the pack case, the second abnormality detection sensor is a sensor that detects at least one of a pressure value, a temperature, and a generated gas inside the pack case, and a voltage value of at least one of the plurality of cells, The controller detects that the pressure value detected by the first anomaly detection sensor is higher than a predetermined threshold value, and In a case where the second abnormality detection sensor is a sensor that detects at least one of a pressure value, a temperature, and a generated gas inside the pack case, when the detection value detected by the second abnormality detection sensor is higher than a predetermined threshold value, In the case where the second anomaly detection sensor is a sensor for detecting a voltage value of at least one of the plurality of cells, when the voltage value detected by the second anomaly detection sensor is lower than a predetermined threshold value, and executing an abnormality determination process to determine that an abnormality has occurred in at least one of the plurality of cells.

Images