Battery system

Abstract

A battery system is provided with a plurality of battery cells, a sealed battery pack case, a first abnormality detection sensor, a second abnormality detection sensor, and a controller. The plurality of battery cells have a sealed battery cell case. The battery cell housing has a first pressure valve configured to irreversibly rupture due to a preset operating pressure. The controller is configured to execute an abnormality determination process for determining that at least one of the plurality of battery cells is abnormal when the pressure value detected by the first abnormality detection sensor is higher than a preset threshold value and the detection value detected by the second abnormality detection sensor is higher than the preset threshold value.

Description

Technical Field

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

[0002] A vehicle battery fire sensing device is disclosed in Japanese Patent Gazette No. 2022-518720, including a battery pack installed on a vehicle structure, an electronic control device, and a communication component. The battery pack includes a battery module, a battery management system, and a battery pack housing. The battery management system sends the signal received from the battery module to the electronic control device. The battery pack housing has a gas exhaust portion for exhausting exhaust gas. The battery pack housing has a sensor for measuring at least one of the temperature and pressure of the gas exhausted from the gas exhaust portion. According to the vehicle battery fire sensing device, when a fire occurs inside the battery pack, the fire can be sensed and notified to the passengers.

[0003] A battery system is disclosed in Japanese Patent Gazette No. 2023-522766, 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 in each sampling cycle. The battery management system calculates a reference pressure based on the internal pressure measured in each sampling cycle. The battery management system calculates the pressure change amount according to the difference between the internal pressure measured in each sampling cycle and the reference pressure. The battery management system determines that a thermal event has occurred in the battery pack when the pressure change amount is above a specified critical pressure and the internal pressure measured in each sampling cycle increases continuously for at least two times. According to this battery system, thermal events of the battery can be sensed.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application No. 2022-518720

[0007] Patent Document 2: Japanese Patent Application No. 2023-522766 Summary of the invention

[0008] The present inventors intend to improve the accuracy of detection when an abnormality occurs in a battery cell.

[0009] The battery system disclosed herein comprises a plurality of battery cells, a sealed battery pack housing, a first abnormality detection sensor, a second abnormality detection sensor and a controller. The battery pack housing accommodates a plurality of battery cells. The first abnormality detection sensor is arranged inside the battery pack housing. The second abnormality detection sensor is arranged inside the battery pack housing. The plurality of battery cells have an electrode body and a sealed battery cell housing accommodating the electrode body. The battery cell housing has a first pressure valve configured to be irreversibly ruptured due to a preset working pressure. The battery pack housing has a second pressure valve released under a preset pressure. The first abnormality detection sensor is a sensor for detecting a pressure value inside the battery pack housing. The second abnormality detection sensor is a sensor for detecting at least one of a pressure value, a temperature and a generated gas inside the battery pack housing. The controller is configured to perform the following abnormality determination processing: when the pressure value detected by the first abnormality detection sensor is higher than a preset threshold value and the detection value detected by the second abnormality detection sensor is higher than a preset threshold value, it is determined that at least one of the plurality of battery cells has an abnormality. In the battery system, the detection accuracy is good when an abnormality occurs in a battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 2 is a schematic diagram showing the battery system 1 .

[0011] Figure 2 : is a flowchart showing the processing executed in the controller 50 .

[0012] Figure 3 It is a schematic diagram showing a battery system 1A according to another embodiment.

[0013] Figure 4 1A is a flowchart showing a process executed by the controller 50 of the battery system 1A. DETAILED DESCRIPTION

[0014] Hereinafter, an embodiment of the technology disclosed herein will be described with reference to the accompanying drawings. The embodiments described herein are of course not intended to specifically limit the present invention. The drawings are schematically drawn and do not necessarily reflect the real objects. In addition, the same reference numerals are appropriately marked for components and parts that play the same role, and repeated descriptions are appropriately omitted.

[0015] <Battery system 1>

[0016] Figure 1 is a schematic diagram showing a battery system 1. The battery system 1 is also called a battery pack and is a collection of batteries (battery cells), a structure for controlling the battery cells, a safety device, etc. Figure 1As shown, the battery system 1 includes a plurality of battery cells 10, a battery pack case 20, a first abnormality detection sensor 30, a second abnormality detection sensor 40, and a controller 50. In addition, the battery system 1 includes a contactor unit 15. The battery pack case 20 is a sealed type, and accommodates a plurality of battery cells 10. The first abnormality detection sensor 30 and the second abnormality detection sensor 40 are arranged inside the battery pack case 20.

[0017] The battery system 1 is connected in series with the load 60 via an external output terminal (not shown) provided on the surface 25 of the battery pack housing 20. In the present embodiment, the battery system 1 is connected to the load 60 of the electric vehicle. Although not particularly limited, the load 60 may be composed of, for example, a motor of the vehicle, an inverter, etc. Electric power is supplied to the load 60 from a plurality of battery cells 10 of the battery system 1. In addition, the load 60 is not limited to this method, and the battery system 1 can also be applied to battery systems other than battery systems mounted on electric vehicles.

[0018] <Multiple battery cells 10>

[0019] A plurality of battery cells 10 have an electrode body (not shown) and a sealed battery cell housing 11. The battery cell 10 is a storage device capable of extracting electrical energy. The battery cell 10 includes a secondary battery that can be repeatedly charged and discharged by moving charge carriers between a pair of electrodes (positive and negative electrodes) via an electrolyte, such as a lithium-ion secondary battery, a nickel-metal hydride battery, etc. There is no particular limitation on the connection method of the plurality of battery cells 10. The plurality of battery cells 10 are electrically connected to each other via a bus bar to form a battery cell module (battery pack) 10A. In addition, the plurality of battery cells 10 can be connected in series, in parallel, or in a combination of series and parallel connection. In the present embodiment, the plurality of battery cells 10 are connected in series.

[0020] The sealed battery cell casing 11 accommodates the electrode body. The battery cell casing 11 is a roughly rectangular container. From the viewpoint of ensuring lightweight and required rigidity, the battery cell casing 11 can be made of aluminum or an aluminum alloy. The battery cell casing 11 has a first pressure valve 12. The first pressure valve 12 is configured to rupture irreversibly due to a preset working pressure. The working pressure of the first pressure valve 12 is not particularly limited and can be appropriately set according to the structure of the battery cell 10, the conditions of use, etc. The first pressure valve 12 can function as a safety device that ruptures when a preset working pressure is reached in the battery cell casing 11, such as when an abnormality occurs in the battery cell 10 and a large amount of gas is rapidly generated in the battery cell casing 11. As a result, the gas generated in the battery cell casing 11 can be released to the outside. The first pressure valve 12 is also called a safety valve. In the present embodiment, a plurality of battery cells 10 are housed in the battery pack casing 20 in the same direction. The first pressure valves 12 respectively provided in the plurality of battery cells 10 face the same direction ( Figure 1 ).

[0021] The plurality of battery cells 10 (battery cell module 10A) are connected to a load 60 via external output terminals, and supply electric power to the load 60. A contactor unit 15 is provided between the plurality of battery cells 10 and the load 60.

[0022] <Contactor unit 15>

[0023] The contactor unit 15 switches the connection between the battery 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 battery 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 battery cell module 10A.

[0024] The pre-charging circuit 16 is a circuit in which a pre-charging resistor 16a and a pre-charging relay 16b are connected in series. The pre-charging circuit 16 is a circuit that prevents surge current from flowing through 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, 18 and the pre-charging relay 16b are in an open state. When the battery system 1 connected to the load 60 is started, the main relay 18 and the pre-charging relay 16b are switched to a closed state. The load 60 is connected to the battery system 1 via the pre-charging circuit 16. At this time, since the pre-charging resistor 16a is provided in the pre-charging circuit 16, power is supplied to the load 60 from the battery cell module 10A at a low current. Afterwards, the main relay 17 is closed in a state where the potential of the load 60 rises, and then the pre-charging relay 16b is opened. Thus, a large current is prevented from flowing through the load 60. The opening and closing of the main relays 17, 18 and the pre-charging relay 16b are controlled by the controller 50 described later. In the present embodiment, the contactor unit 15 is provided in the battery pack case 20 similarly to the battery cell module 10A.

[0025] <Battery Pack Case 20>

[0026] The battery pack case 20 is a sealed container that accommodates a plurality of battery cells 10 and the like. The battery pack case 20 is roughly rectangular. From the viewpoint of ensuring light weight and required rigidity, the battery pack case 20 can be made of aluminum or an aluminum alloy, respectively. The battery pack case 20 has a second pressure valve 22 that is released at a preset pressure. The second pressure valve 22 is different from the first pressure valve 12 provided on the battery cell 10, and is a structure for adjusting the internal pressure when the internal pressure rises. After the internal pressure of the battery pack case 20 is adjusted, the second pressure valve 22 is closed, and the battery pack case 20 is sealed again. The working pressure of the second pressure valve 22 is not particularly limited and can be appropriately set according to the structure of the battery system 1, usage conditions, etc.

[0027] The second pressure valve 22 is disposed at a position that is not opposite to the first pressure valve 12 disposed on the plurality of battery cells 10. By disposing the second pressure valve 22 at a position that is not opposite to the first pressure valve 12, damage to the second pressure valve 22 caused by the operation of the first pressure valve 12 can be suppressed. In the present embodiment, the second pressure valve 22 is disposed at a position 23a that is not opposite to the first pressure valve 12 and on the surface 23 that is opposite to the first pressure valve 12. The second pressure valve 22 may also be disposed on other surfaces 24 to 26 of the battery pack case 20.

[0028] In addition, in a battery system 1 in which a plurality of battery cells 10 are accommodated in a sealed battery pack housing 20, a battery cell 10 may malfunction due to an unexpected impact from the outside or the like. At this time, various reactions may occur in the battery cell housing 11 of the abnormal battery cell 10, generating gas. As a result, the pressure in the battery cell housing 11 rises. If the pressure in the battery cell housing 11 reaches a preset working pressure, the first pressure valve 12 ruptures irreversibly. As a result, gas is released into the battery pack housing 20. As a result, the pressure in the battery pack housing 20 may rise. In addition, if an abnormality occurs in the battery cell 10, there is a concern that the temperature of the battery cell 10 may rise.

[0029] In the battery system 1 , the first abnormality detection sensor 30 and the second abnormality detection sensor 40 are housed inside the battery pack case 20 together with the battery cell module 10A.

[0030] <First abnormality detection sensor 30>

[0031] The first abnormality detection sensor 30 is a sensor that detects the pressure value in the battery pack case 20. The first abnormality detection sensor 30 is configured, for example, to detect the pressure value of the gas in the battery 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 in the battery pack case 20. The first abnormality detection sensor 30 can be arranged at a position that is not opposite to the first pressure valve 12 (position 23a in this embodiment). Therefore, when the first pressure valve 12 is working, the first abnormality detection sensor 30 is not easily affected by the pressure value that may change locally in a short period of time, and it is easy to stably detect the pressure value.

[0032] A plurality of first abnormality detection sensors 30 may be provided in the battery pack case 20. When a plurality of first abnormality detection sensors 30 are provided, the first abnormality detection sensors 30 may be configured to detect pressure values ​​at different positions in the battery pack case 20. Thus, even when the battery pack case 20 is large, it is easy to detect a pressure abnormality occurring in the battery pack case 20.

[0033] <Second abnormality detection sensor 40>

[0034] The second abnormality detection sensor 40 is a sensor that detects at least one of the pressure value, temperature, and generated gas in the battery pack case 20. As the second abnormality detection sensor 40, a sensor that can detect abnormality based on the composition or state of the gas in the battery pack case 20 can be used. In the present embodiment, the second abnormality detection sensor 40 is a sensor that detects the pressure value in the battery pack case 20 in the same way as the first abnormality detection sensor 30. The second abnormality detection sensor 40 can be arranged at a position that is not opposite to the first pressure valve 12. The second abnormality detection sensor 40 is configured to detect the pressure value of the gas in the battery pack case 20 and output it to the controller 50. The structure of the second abnormality detection sensor 40 can be set to the same structure as the first abnormality detection sensor 30, so the detailed description is omitted.

[0035] <Controller 50>

[0036] The controller 50 is configured to perform an abnormality determination process for determining whether an abnormality occurs in at least any one of the multiple battery cells 10. In addition, the controller 50 controls the contactor unit 15 to control the connection and disconnection between the load 60 and the multiple battery cells 10. The controller 50 can also supply power from a power supply 80 provided outside the battery pack housing 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 indication unit 55. Each unit 51 to 55 of the controller 50 can be implemented by one or more processors, or can be embedded in a circuit. The controller 50 is connected to a higher-level controller 70 provided outside the battery pack housing 20 via the communication unit 53 in a communicative manner.

[0037] The upper controller 70 controls the controller 50 that controls the connection and disconnection between the load 60 and the plurality of battery cells 10. The upper controller 70 is connected to the controller 50 in a communicative manner. The upper controller 70 may be, for example, an on-vehicle ECU (Electronic Control Unit). In the present embodiment, the controller 50 determines whether an abnormality occurs in the battery cell 10. The following is a description of the process of determining an abnormality of the battery cell 10 executed in the controller 50.

[0038] In the present embodiment, the pressure value detected by the first abnormality detection sensor 30 and the second abnormality detection sensor 40 is notified to the controller 50. The first abnormality detection sensor 30 and the second abnormality detection sensor 40 can detect the pressure value at a preset interval and notify the controller 50. The interval of detection and notification is not particularly limited, and can be set to about 0.1 second to 1 second, for example.

[0039] When 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 controller 50 performs an abnormality determination process of whether an abnormality occurs in the battery cell 10 .

[0040] Figure 2 : is a flowchart showing the processing executed in the controller 50. Threshold values ​​Th1 and Th2 of the pressure values ​​notified from the first abnormality detection sensor 30 and the second abnormality detection sensor 40 are set in the controller 50. In the present embodiment, the threshold value 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 working pressure for operating the second pressure valve 22. The threshold value Th2 of the pressure value detected by the second abnormality detection sensor 40 is set to the same value as the threshold value of the pressure value detected by the first abnormality detection sensor 30. In addition, the threshold values ​​Th1 and Th2 detected by the first abnormality detection sensor 30 and the second abnormality detection sensor 40 may be different values.

[0041] When the controller 50 is started, the abnormality determination process is started. The abnormality determination process may be always executed when the battery system 1 is started. Figure 2 In step S10, the first acquisition unit 51 of the controller 50 acquires the pressure value detected by the first abnormality detection sensor 30 (hereinafter also referred to as "first pressure value P1"). The determination unit 54 determines whether the first pressure value P1 is less than the threshold value Th1. When the first pressure value P1 is less than the threshold value Th1 (yes), the process proceeds to step S30.

[0042] exist Figure 2 In step S30, the second acquisition unit 52 of the controller 50 acquires the pressure value detected by the second abnormality detection sensor 40 (hereinafter also referred to as "second pressure value P2"). The determination unit 54 determines whether the second pressure value P2 is below the threshold value Th2. When the second pressure value P2 is below the threshold value Th2 (yes), it is determined that the multiple battery cells 10 in the battery pack case 20 are normal. In addition, when the battery system 1 is started, the abnormality determination process is started again. The abnormality determination process can be performed until the battery system 1 is stopped.

[0043] exist Figure 2 In step S10, when the first pressure value P1 is higher than the threshold value Th1 (No), the process proceeds to step S20. Figure 2 In step S20, similarly to step S30, it is determined whether the second pressure value P2 is less than the threshold value Th2. If the second pressure value P2 is higher than the threshold value Th2 (No), similarly to the first pressure value P1, it is determined that at least one of the plurality of battery cells 10 in the battery pack case 20 is abnormal.

[0044] Thus, in the battery system 1, when the first pressure value P1 detected by the first abnormality detection sensor 30 is higher than the preset threshold value Th1 and the detection value detected by the second abnormality detection sensor 40 (the second pressure value P2 in the present embodiment) is higher than the preset threshold value Th2, the controller 50 determines that an abnormality has occurred in at least any one of the multiple battery cells 10.

[0045] In the above-mentioned embodiment, the battery system 1 is provided with a first abnormality detection sensor 30 for detecting the pressure value in the battery pack case 20. Thus, when an abnormality occurs in any of the plurality of battery cells 10, it is possible to detect that the pressure value in the battery pack case 20 increases due to the gas released from the abnormal battery cell 10. In addition, the battery system 1 is provided with a second abnormality detection sensor 40. Thus, the abnormality can be detected with higher accuracy. When it is determined that an abnormality occurs in the battery cell 10 of the battery system 1, the abnormality of the battery cell 10 can be notified from the controller 50 to the upper controller 70. The abnormality of the battery cell 10 can be notified to the user from the upper controller 70. The user can recognize that an abnormality occurs in the battery cell 10 of the battery system 1 and can take appropriate countermeasures such as inspection and repair.

[0046] In the above-described embodiment, the threshold Th1 of the first pressure value P1 detected by the first abnormality detection sensor 30 is set to a value higher than the atmospheric pressure and lower than the operating pressure for operating the second pressure valve 22. This makes it easier to detect an abnormality in the battery cell 10 before the second pressure valve 22 operates to release gas in the battery pack.

[0047] In the above-mentioned embodiment, the second abnormality detection sensor 40 is a sensor that detects the pressure value in the battery pack case 20. The second abnormality detection sensor 40 detects the pressure value in the battery pack case 20 in the same manner as the first abnormality detection sensor 30. The first abnormality detection sensor 30 and the second abnormality detection sensor 40 use the same detection value as an indicator to determine the abnormality of the battery cell 10, so it is not easy to cause a deviation in the determination conditions between the sensors. As a result, the abnormality of the battery cell 10 can be detected more quickly with higher accuracy.

[0048] In addition, in the battery system 1, when an abnormality of a battery cell 10 is detected, the load 60 may be disconnected from the plurality of battery cells 10 in order to ensure safety. In the present embodiment, the controller 50 is configured to execute a process of controlling the contactor unit 15 to be in a disconnected state when an abnormality of a battery 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 the battery cell 10, the indication unit 55 controls the contactor unit 15 to be in a disconnected state. In the present embodiment, at least one of the main relays 17 and 18 is controlled to be in a disconnected state. By disconnecting the connection with the load 60 when an abnormality occurs in the battery cell 10, safety can be improved.

[0049] In addition, a mechanism for determining whether a failure occurs in either the first abnormality detection sensor 30 or the second abnormality detection sensor 40 may be provided in the battery system 1. In the present embodiment, the controller 50 is configured to execute a failure determination process for determining whether a failure occurs in either the first abnormality detection sensor 30 or the second abnormality detection sensor 40.

[0050] 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 less than the threshold value Th2 (Yes), the process proceeds to step S25. Figure 2 In step S25, it is determined whether the time t2 after the second pressure value P2 is determined to be less than the threshold value Th2 in step S20 exceeds the specified time T2. The specified time T2 can be preset within a range that is long enough to detect the abnormality of the sensor and the abnormality of the sensor does not hinder the operation of the battery system 1.

[0051] In step S25, when the elapsed time t2 does not exceed the prescribed time T2 (No), the process returns to step S20. The process of determining whether the second pressure value P2 is below the threshold value Th2 is performed again. Here, when 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 the battery cell 10 of the battery system 1 is abnormal.

[0052] In step S25, when the elapsed time t2 exceeds the prescribed time T2 (yes), the state in which the first pressure value P1 is higher than the threshold value Th1 and the second pressure value P2 is less than the threshold value Th2 continues. In this case, the judgments of the first abnormality detection sensor 30 and the second abnormality detection sensor 40 are different. Here, although the second pressure value P2 continues to be less than the threshold value Th2 after the prescribed time T2, the first pressure value P1 is higher than the threshold value Th1. The determination unit 54 determines that the first abnormality detection sensor 30 has failed. The communication unit 53 of the controller 50 notifies the upper controller 70 that the first abnormality detection sensor 30 may have failed. The user can recognize that the first abnormality detection sensor 30 of the battery system 1 has an abnormality and can take appropriate countermeasures such as inspection and repair.

[0053] After it is determined in the above step S30 that the second pressure value P2 is higher than the threshold value Th2 (No), Figure 2 In step S40, similarly to step S10, it is determined whether the first pressure value P1 is below the threshold value Th1. When 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 at least one of the multiple battery cells 10 in the battery pack case 20 is abnormal. In step S40, when the first pressure value P1 is below the threshold value Th1 (Yes), the process proceeds to step S45. Figure 2 In step S45, it is determined whether the time t1 after the first pressure value P1 is determined to be less than the threshold value Th1 in step S40 exceeds the predetermined time T1. The predetermined time T1 may be the same as or different from the predetermined time T2 described above.

[0054] In step S45, if the elapsed time t1 does not exceed the predetermined time T1 (No), the process returns to step S40 to determine whether the first pressure value P1 is less than the threshold value Th1. Here, if the first pressure value P1 is determined to be higher than the threshold value Th1, it is determined that an abnormality has occurred in the battery cell 10 of the battery system 1.

[0055] In step S45, when the elapsed time t1 exceeds the prescribed time T1 (yes), the state in which the second pressure value P2 is higher than the threshold value Th2 and the first pressure value P1 is below the threshold value Th1 continues. In this case, the judgments of the first abnormality detection sensor 30 and the second abnormality detection sensor 40 are different. Here, although the first pressure value P1 continues to be below the threshold value Th1 after the prescribed time T1, the second pressure value P2 is higher than the threshold value Th2. The determination unit 54 determines that the second abnormality detection sensor 40 has failed. The communication unit 53 of the controller 50 notifies the upper controller 70 that the second abnormality detection sensor 40 may have failed. The user can recognize that the second abnormality detection sensor 40 of the battery system 1 has an abnormality and can take appropriate countermeasures such as inspection and repair.

[0056] Thus, in the battery system 1, when one of the first pressure value P1 detected by the first abnormality detection sensor 30 and the detection value (the second pressure value P2 in the present embodiment) detected by the second abnormality detection sensor 40 is higher than a predetermined threshold value and the other is below the predetermined threshold value for a predetermined time T1, T2, it is determined that a failure has occurred in either the first abnormality detection sensor 30 or the second abnormality detection sensor 40.

[0057] Furthermore, the battery system 1 may be configured to switch between a low power consumption mode for suppressing power consumption and a normal mode for supplying power to the load 60. For example, when the battery system 1 is used as a vehicle-mounted battery, it may switch to the power saving mode when the power of the electric vehicle is turned off, and switch to the normal mode when the electric vehicle is running. In addition, the battery system 1 may switch to the normal mode when charging.

[0058] In the present embodiment, the controller 50 is configured to be able to switch between the low power consumption mode and the normal mode. In the normal mode, the above-mentioned processing is performed, and the processing of detecting the abnormality of the battery cell 10 included in the battery system 1 is performed. In the low power consumption mode, processing different from the above-mentioned processing can be performed. For example, in order to suppress power consumption, the above-mentioned abnormality detection processing and other processing can be stopped.

[0059] In the present embodiment, a process for early detection of an abnormality of the battery cell 10 is also performed in the low power consumption mode. Here, the first acquisition unit 51 and the second acquisition unit 52 of the controller 50 acquire the pressure value (first pressure value P1) detected by the first abnormality detection sensor 30 and the detection value (second pressure value P2) detected by the second abnormality detection sensor 40. The determination unit 54 determines whether 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 preset threshold value. Here, it is determined whether the first pressure value P1 is higher than the threshold value Th1, and it is determined whether 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 indication unit 55 indicates the 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 above-mentioned abnormality detection process is performed. As a result, it is possible to early detect an abnormality of the battery cell 10 that may occur after switching to the low power consumption mode.

[0060] In the present embodiment, a first abnormality detection sensor 30 and a second abnormality detection sensor 40 are provided, and they can mutually confirm whether they are operating normally through the control of the controller 50. However, the present invention is not limited to this method, and a self-diagnosis function for confirming whether the first abnormality detection sensor 30 itself is operating normally may be provided in the battery system 1. The self-diagnosis function may be provided in the first abnormality detection sensor 30, or may be configured to cooperate with the controller 50. By providing the self-diagnosis function, it is also possible to detect abnormalities in the battery cell 10 without using the second abnormality detection sensor 40. In this way, the space of the battery system 1 can be saved.

[0061] In the above-described embodiment, the second abnormality detection sensor 40 is a sensor that detects the pressure value in the battery pack case 20. However, the second abnormality detection sensor 40 is not limited to this form.

[0062] For example, the second abnormality detection sensor 40 may also be a sensor that detects the temperature inside the battery pack case 20. When a temperature sensor is used as the second abnormality detection sensor 40, the second abnormality detection sensor 40 may be arranged, for example, in the path of the gas discharged from the first pressure valve 12 when an abnormality occurs in the battery cell 10. By detecting the temperature of the high-temperature gas released from the battery cell 10 by the second abnormality detection sensor 40, the abnormality of the battery cell 10 can be detected as early as possible. In addition, the threshold value for determining the abnormality of the battery cell 10 based on the detection value (temperature) of the temperature sensor can be appropriately set according to the structure and specifications of the battery cell 10.

[0063] In addition, the second abnormality detection sensor 40 may also be a sensor that detects the generation of gas in the battery pack housing 20. When a gas sensor is used as the second abnormality detection sensor 40, the second abnormality detection sensor 40 may be configured, for example, in the path of the gas discharged from the first pressure valve 12 when an abnormality occurs in the battery cell 10. By detecting the specified gas released from the battery cell 10 by the second abnormality detection sensor 40, the abnormality of the battery cell 10 can be detected as early as possible. When a gas sensor is used as the second abnormality detection sensor 40, the threshold value for determining the abnormality of the battery cell 10 may also be set according to the composition and concentration of the gas. Although not particularly limited, as the components of the gas to be detected by the gas sensor, for example, carbon dioxide, hydrocarbons, etc. can be listed. The composition of the gas to be detected by the gas sensor, the gas concentration, etc., can be appropriately set according to the structure, specifications, etc. of the battery cell 10. The gas sensor may also be a sensor for detecting smoke.

[0064] In addition, the second abnormality detection sensor may be a sensor that detects the voltage value of the battery cell in the battery pack case. Figure 3 Schematic diagram showing a battery system 1A according to another embodiment. Figure 3 In the description of the battery system 1A shown, the same reference numerals are appropriately assigned to components and locations that perform the same functions, and duplicate descriptions are appropriately omitted.

[0065] <Battery system 1A>

[0066] like Figure 3 As shown, the battery system 1A includes a plurality of battery cells 10, a battery pack housing 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 battery pack housing 20. The battery system 1A may also include a second abnormality detection sensor 40A in place of the second abnormality detection sensor 40 (see Figure 1 ) in addition to the battery system 1 (refer to Figure 1 ) have the same structure.

[0067] <Second Abnormality Detection Sensor 40A>

[0068] The second abnormality detection sensor 40A is a sensor that detects at least one of the pressure value, temperature, generated gas, and voltage of the battery cell 10 in the battery pack case 20. The second abnormality detection sensor 40A may be configured to detect the voltage value of the battery cell 10 in addition to the second abnormality detection sensor 40 (see Figure 1). As the second abnormality detection sensor 40A, a voltage sensor may be used. The second abnormality detection sensor 40A may be composed of a plurality of sensors or a single sensor (for example, a voltage sensor). The second abnormality detection sensor 40A may also be composed by combining a sensor that detects at least one of a pressure value, a temperature, and a generated gas and a voltage sensor.

[0069] In the present embodiment, the second abnormality detection sensor 40A is a sensor that detects the voltage of the battery cell 10. Here, the "voltage of the battery cell 10" is the voltage of at least any one of the multiple battery cells 10. The second abnormality detection sensor 40A may also detect the voltage value of each battery cell 10. The second abnormality detection sensor 40A may detect the voltage value of one or more of the multiple battery cells 10, or may detect the voltage value of the multiple battery cells 10 as a whole (the so-called total voltage). In the present embodiment, the second abnormality detection sensor 40A detects the voltage value of each battery cell 10. The voltage value detected by the second abnormality detection sensor 40A is sent to the controller 50.

[0070] The controller 50 sets a threshold value of the voltage value sent from the second abnormality detection sensor 40A. When the voltage value detected by the second abnormality detection sensor 40A is lower than the preset threshold value, the controller 50 determines that at least one of the plurality of battery cells 10 has an abnormality.

[0071] The threshold value may be changed according to the characteristics of the battery cell 10 used in the battery system 1A. Therefore, the threshold value may be set after the voltage characteristics of the battery cell 10 are verified in advance through experiments or the like. According to the experiments of the inventors, the following phenomenon has been confirmed: when an abnormality occurs in any of the battery cells 10 among the plurality of battery cells 10, when gas is released from the abnormal battery cell 10, the voltage of the abnormal battery cell 10 also drops sharply. The threshold value of the voltage value may also be set to, for example, the termination voltage of the battery cell 10.

[0072] Figure 4 1A is a flowchart showing the processing executed by the controller 50 of the battery system 1A. Figure 4 In addition to executing the determination of steps S21 and S31 instead of Figure 2 In addition to steps S20 and S30, Figure 2 The processing shown is the same, so repeated descriptions are omitted as appropriate.

[0073] If it is determined in step S10 that the first pressure value P1 is less than the threshold value Th1 (Yes), the process proceeds to step S11. Figure 4In step S31, it is determined whether the voltage value V is greater than the threshold value Vth. If the voltage value V is greater than the threshold value Vth (yes), it is determined that the plurality of battery cells 10 in the battery pack case 20 are normal. If it is determined in step S31 that the voltage value V is less than the threshold value Vth (no), the process proceeds to step S40. After step S40, the same steps as in Figure 2 The same processing as described in .

[0074] 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 S11. Figure 4 In step S21, it is determined whether the voltage value V is greater than the threshold value Vth. If the voltage value V is lower than the threshold value Vth (no), it is determined that at least one of the multiple battery cells 10 in the battery pack housing 20 is abnormal. If it is determined in step S21 that the voltage value V is greater than the threshold value Vth (yes), the process proceeds to step S25. After step S25, the same procedure as in Figure 2 The same processing as described in .

[0075] By using the second abnormality detection sensor 40A that detects the voltage of the battery cell 10, in addition to the increase in the pressure value in the battery pack case 20, the phenomenon of the voltage value of the battery cell 10 decreasing can be detected. As a result, the abnormality of the battery cell 10 can be detected as early as possible. In addition, when the second abnormality detection sensor 40A can detect the voltage value of each of the plurality of battery cells 10, it can be detected which battery cell 10 in the battery pack case 20 has an abnormality. As a result, it is easy to take countermeasures after the abnormality occurs.

[0076] The battery system disclosed herein comprises a plurality of battery cells, a sealed battery pack housing, a first abnormality detection sensor, a second abnormality detection sensor and a controller. The battery pack housing accommodates a plurality of battery cells. The first abnormality detection sensor is arranged inside the battery pack housing. The second abnormality detection sensor is arranged inside the battery pack housing. The plurality of battery cells have an electrode body and a sealed battery cell housing for accommodating the electrode body. The battery cell housing has a first pressure valve configured to rupture irreversibly due to a preset working pressure. The battery pack housing has a second pressure valve that is released under a preset pressure. The first abnormality detection sensor is a sensor that detects a pressure value inside the battery pack housing. The second abnormality detection sensor is a sensor that detects at least one of the pressure value, temperature, generated gas and voltage value of at least any one of the plurality of battery cells inside the battery pack housing. In the case where the second abnormality detection sensor is a sensor capable of detecting at least one of the pressure value, temperature, and generated gas in the battery pack case, the controller is configured to perform the following abnormality determination processing: when the pressure value detected by the first abnormality detection sensor is higher than a preset threshold value and the detection value detected by the second abnormality detection sensor is higher than a preset threshold value, it is determined that at least one of the plurality of battery cells has an abnormality. In the case where the second abnormality detection sensor is a sensor that detects the voltage value of at least one of the plurality of battery cells, the controller is configured to perform the following abnormality determination processing: when the pressure value detected by the first abnormality detection sensor is higher than a preset threshold value and the voltage value detected by the second abnormality detection sensor is lower than a preset threshold value, it is determined that at least one of the plurality of battery cells has an abnormality. In this battery system, the detection accuracy when an abnormality occurs in a battery cell is good.

[0077] Above, various descriptions have been made to the technology disclosed herein. As long as no special mention is made, the embodiments listed here, etc. do not limit the present invention. In addition, the technology disclosed herein can be variously changed, and as long as no special problem is generated, each component or each process mentioned herein can be appropriately omitted or appropriately combined. In addition, this specification includes the following disclosures described in each item.

[0078] Item 1: A battery system comprising:

[0079] Multiple battery cells;

[0080] A sealed battery pack housing that contains the plurality of battery cells;

[0081] A first abnormality detection sensor is disposed inside the battery pack housing;

[0082] A second abnormality detection sensor is disposed inside the battery pack housing; and

[0083] Controller,

[0084] The plurality of battery cells include an electrode body and a sealed battery cell case for housing the electrode body.

[0085] The battery cell housing has a first pressure valve which is designed to rupture irreversibly due to a predefined working pressure.

[0086] The battery pack housing has a second pressure valve that is released at a preset pressure.

[0087] The first abnormality detection sensor is a sensor that detects the pressure value inside the battery pack case.

[0088] The second abnormality detection sensor is a sensor that detects at least one of the pressure value, temperature, generated gas, and voltage value of at least any one of the plurality of battery cells in the battery pack case.

[0089] In the 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 in the battery pack case, the controller is configured to perform the following abnormality determination processing: when the pressure value detected by the first abnormality detection sensor is higher than a preset threshold value and the detection value detected by the second abnormality detection sensor is higher than a preset threshold value, it is determined that at least any one of the plurality of battery cells has an abnormality,

[0090] In the case where the second abnormality detection sensor is a sensor that detects the voltage value of at least any one of the multiple battery cells, the controller is configured to perform the following abnormality judgment processing: when the pressure value detected by the first abnormality detection sensor is higher than a preset threshold and the voltage value detected by the second abnormality detection sensor is lower than a preset threshold, it is judged that at least any one of the multiple battery cells has an abnormality.

[0091] Item 2: In the battery system described in Item 1, the first abnormality detection sensor and the second abnormality detection sensor are arranged at positions that do not face the first pressure valve.

[0092] Item 3: In the battery system according to Item 1 or 2, 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 for operating the second pressure valve.

[0093] Item 4: In the battery system according to any one of Items 1 to 3,

[0094] The controller is configured to be able to switch between a low power consumption mode and a normal mode.

[0095] In the low power mode,

[0096] The controller is configured to execute a process of acquiring a pressure value detected by the first abnormality detection sensor and the detection value detected by the second abnormality detection sensor,

[0097] 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 preset threshold, the low power consumption mode is switched to the normal mode to execute the abnormality determination process.

[0098] Item 5: In the battery system according to any one of Items 1 to 4,

[0099] The battery system further includes a contactor unit for switching the connection between the plurality of battery cells and the load.

[0100] The controller is configured to execute a process of controlling the contactor unit to be in an OFF state when an abnormality of the battery cell is detected in the abnormality determination process.

[0101] Item 6: In the battery system according to any one of Items 1 to 5, the second abnormality detection sensor is a sensor that detects a pressure value inside the battery pack case.

[0102] Item 7: In the battery system according to any one of Items 1 to 5, the second abnormality detection sensor is a sensor that detects a temperature inside the battery pack case.

[0103] Item 8: In the battery system according to any one of Items 1 to 5, the second abnormality detection sensor is a sensor that detects gas generated in the battery pack case.

[0104] Item 9: In the battery system described in any one of Items 1 to 8, the controller is configured to perform the following processing: when a predetermined time has passed while 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 below the predetermined threshold, it is determined that a failure has occurred in either the first abnormality detection sensor or the second abnormality detection sensor.

[0105] Item 10: In the battery system according to any one of Items 1 to 9, the second abnormality detection sensor is a sensor that detects at least one of a pressure value, a temperature, and a generated gas in the battery pack case.

[0106] Item 11: In the battery system according to any one of Items 1 to 9, the second abnormality detection sensor is a sensor that detects a voltage value of at least any one of the plurality of battery cells.

Claims

1. A battery system, wherein: have: Multiple battery cells; A sealed battery pack housing that contains the plurality of battery cells; A first abnormality detection sensor is disposed inside the battery pack housing; A second abnormality detection sensor is disposed inside the battery pack housing; and Controller, The plurality of battery cells include an electrode body and a sealed battery cell case for housing the electrode body. The battery cell housing has a first pressure valve which is designed to rupture irreversibly due to a predefined working pressure. The battery pack housing has a second pressure valve that is released at a preset pressure. The first abnormality detection sensor is a sensor that detects the pressure value inside the battery pack case. The second abnormality detection sensor is a sensor that detects at least one of the pressure value, temperature, generated gas, and voltage value of at least any one of the plurality of battery cells in the battery pack case. In the 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 in the battery pack case, the controller is configured to perform the following abnormality determination processing: when the pressure value detected by the first abnormality detection sensor is higher than a preset threshold value and the detection value detected by the second abnormality detection sensor is higher than a preset threshold value, it is determined that at least any one of the plurality of battery cells has an abnormality, In the case where the second abnormality detection sensor is a sensor that detects the voltage value of at least any one of the multiple battery cells, the controller is configured to perform the following abnormality judgment processing: when the pressure value detected by the first abnormality detection sensor is higher than a preset threshold and the voltage value detected by the second abnormality detection sensor is lower than a preset threshold, it is judged that at least any one of the multiple battery cells has an abnormality.

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

3. The battery system according to claim 1 or 2, wherein: The threshold value of the pressure value detected by the first abnormality detection sensor is set to a value higher than the atmospheric pressure and lower than the operating pressure for operating the second pressure valve.

4. The battery system according to claim 1 or 2, wherein: The controller is configured to be able to switch between a low power consumption mode and a normal mode. In the low power mode, The controller is configured to execute a process of acquiring a pressure value detected by the first abnormality detection sensor and the detection value detected by the second abnormality detection sensor, 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 preset threshold, the low power consumption mode is switched to the normal mode to execute the abnormality determination process.

5. The battery system according to claim 1 or 2, wherein: The battery system further includes a contactor unit for switching the connection between the plurality of battery cells and the load. The controller is configured to execute a process of controlling the contactor unit to be in an OFF state when an abnormality of the battery cell is detected in the abnormality determination process.

6. The battery system according to claim 1 or 2, wherein: The second abnormality detection sensor is a sensor that detects a pressure value inside the battery pack case.

7. The battery system according to claim 1 or 2, wherein: The second abnormality detection sensor is a sensor that detects the temperature inside the battery pack case.

8. The battery system according to claim 1 or 2, wherein: The second abnormality detection sensor is a sensor that detects gas generation in the battery pack case.

9. The battery system according to claim 1 or 2, wherein: The controller is configured to perform the following processing: when a predetermined time has passed while 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 below the predetermined threshold, it is determined that a failure has occurred in either the first abnormality detection sensor or the second abnormality detection sensor.

10. The battery system according to claim 1 or 2, wherein: The second abnormality detection sensor is a sensor that detects at least one of a pressure value, a temperature, and a generated gas in the battery pack case.

11. The battery system according to claim 1 or 2, wherein: The second abnormality detection sensor is a sensor that detects a voltage value of at least any one of the plurality of battery cells.

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