Battery thermal runaway warning method and battery system

Abstract

The application provides a battery thermal runaway alarm method and a battery system. The method comprises the following steps: obtaining a current state of a fault diagnosis state machine; the fault diagnosis state machine is used for fault diagnosis on a battery unit and state switching based on a fault diagnosis result; if the current state of the fault diagnosis state machine is an abnormal operation state, obtaining parameter information of the battery unit; the abnormal operation state comprises at least one of a forbidden charging state, a forbidden discharging state and a fault power-off state, and the parameter information comprises at least one of temperature change information, voltage change information, trigger protection information and output correlation information; if the parameter information of the battery unit is abnormal, performing thermal runaway alarm on the battery unit. The application can alarm the thermal runaway phenomenon that still occurs after the battery is controlled based on the fault diagnosis state machine, so as to remind the staff that the battery unit still has thermal runaway, and the battery unit is prevented from being damaged.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a battery thermal runaway alarm method and battery system. Background Technology

[0002] Currently, fault diagnosis state machines are commonly used to diagnose battery faults. When the battery temperature is too high, the fault diagnosis state machine will switch states. The battery's BMS (Battery Management System) will control the battery state according to the state of the fault diagnosis state machine and issue a thermal runaway alarm, thereby controlling the battery temperature from becoming too high.

[0003] However, the inventors discovered that in practical applications, even after controlling the battery based on a fault diagnosis state machine, the battery still continues to experience thermal runaway. Existing methods cannot provide warnings for this thermal runaway, which may damage the battery. Summary of the Invention

[0004] This invention provides a battery thermal runaway alarm method and battery system to solve the problem that it is currently impossible to alarm for thermal runaway phenomena that still occur after the battery is controlled based on a fault diagnosis state machine, which may lead to battery damage.

[0005] In a first aspect, embodiments of the present invention provide a battery thermal runaway alarm method, comprising:

[0006] Obtain the current state of the fault diagnosis state machine; the fault diagnosis state machine is used to diagnose faults in battery cells and switch states based on the fault diagnosis results.

[0007] If the current state of the fault diagnosis state machine is an abnormal operation state, then the parameter information of the battery cell is obtained; wherein, the abnormal operation state includes at least one of the following: charging-prohibited state, discharging-prohibited state, and fault power-off state, and the parameter information includes at least one of the following: temperature change information, voltage change information, trigger protection information, and output association information;

[0008] If the parameter information of the battery cell is abnormal, a thermal runaway alarm for the battery cell will be triggered.

[0009] In one possible implementation, the abnormality of the battery cell parameter information includes at least one of the following: the battery cell temperature change information meets a first preset condition, the battery cell voltage change information meets a second preset condition, the battery cell trigger protection information meets a third preset condition, and the battery cell output association information meets a fourth preset condition.

[0010] In one possible implementation, the temperature change information of the battery cell includes the current temperature of the battery cell and the current temperature rise rate; the first preset condition includes that the current temperature of the battery cell is greater than the preset temperature corresponding to the battery cell, and the current temperature rise rate of the battery cell is greater than the first temperature rise rate threshold corresponding to the battery cell.

[0011] The battery change information of the battery cell includes the current voltage of the battery cell and the current voltage change trend; the second preset condition includes that the current voltage of the battery cell is greater than the preset voltage corresponding to the battery cell, and the current voltage change trend of the battery cell is an upward trend.

[0012] The battery cell's trigger protection information includes whether the battery cell has triggered overvoltage protection and the current SOC of the battery cell; the third preset condition includes the battery cell triggering overvoltage protection and the absolute value of the difference between the current SOC of the battery cell and the theoretical SOC of the battery cell being greater than the first preset difference corresponding to the battery cell.

[0013] The battery cell's output-related information includes the battery cell's current output current and the battery cell's relay fault reporting information; the fourth preset condition includes the battery cell's current output current being 0 and the battery cell's relay fault reporting information being a non-reported relay sticking fault; the battery cell's relay is used to connect the battery cell and the charging / discharging device.

[0014] In one possible implementation, thermal runaway alarm for the battery cell includes:

[0015] Based on the parameter information of the battery cell and the parameter information of each first battery cell located around the battery cell, the thermal runaway type of the battery cell is determined, and a corresponding alarm is issued according to the thermal runaway type of the battery cell. The thermal runaway type includes thermal runaway propagation and individual thermal runaway.

[0016] In one possible implementation, the parameter information of the battery cell includes the current temperature rise rate of the battery cell; the parameter information of the first battery cell includes the current temperature rise rate of the first battery cell.

[0017] Based on the parameter information of the battery cell and the parameter information of each first battery cell located around the battery cell, the thermal runaway type of the battery cell is determined, including:

[0018] If the current temperature rise rate of the battery cell is greater than the second temperature rise rate threshold, and there is a first battery cell in each first battery cell whose current temperature rise rate is greater than the third temperature rise rate threshold, then the thermal runaway type of the battery cell is determined to be thermal runaway propagation; otherwise, the thermal runaway type of the battery cell is determined to be isolated thermal runaway.

[0019] Among them, the second temperature rise rate threshold is greater than the third temperature rise rate threshold.

[0020] In one possible implementation, the battery thermal runaway alarm method also includes:

[0021] Based on the parameter information of the battery module containing each battery cell and the parameter information of each battery cell contained in the battery module, it is determined whether there is a loose connection fault in the terminal block corresponding to the battery module, and a corresponding alarm is issued when there is a loose connection fault in the terminal block corresponding to the battery module; wherein, each battery cell in the battery module is connected through the terminal block corresponding to the battery module.

[0022] In one possible implementation, the battery module's parameter information includes the battery module's current voltage, DC internal resistance, and discharge capacity in a low-current discharge state; the battery module is in a low-current discharge state when the discharge current is less than a preset discharge current.

[0023] The battery cell's parameter information includes the battery cell's current voltage, current temperature, and current rate of temperature rise;

[0024] Based on the parameter information of the battery module containing each battery cell and the parameter information of each battery cell contained in the battery module, determine whether there is a loose connection fault in the corresponding terminal block of the battery module, including:

[0025] If at least one of the following conditions is met: the current voltage of the battery module and the current voltage of each battery cell meet the fifth preset condition; the current temperature rise rate of each battery cell meets the sixth preset condition; the current temperature of each battery cell meets the seventh preset condition; and the DC internal resistance of the battery module and the discharge capacity of the battery module in the low current discharge state meet the eighth preset condition, then it is determined that there is a loose connection fault in the terminal block corresponding to the battery module.

[0026] In one possible implementation, the fifth preset condition includes: the battery cells are connected in series and the absolute value of the difference between the sum of the current voltages of the battery cells in the battery module and the current voltage of the battery module is greater than or equal to the first preset voltage difference; or, the battery cells are connected in parallel and the absolute value of the difference between the current voltage of at least one battery cell in the battery module and the current voltage of the battery module is greater than or equal to the second preset voltage difference.

[0027] The sixth preset condition includes that the current temperature rise rate of at least one battery cell in the battery module is greater than the fourth temperature rise rate threshold.

[0028] The seventh preset condition includes that the difference between the current temperature of the battery cell close to the terminal block corresponding to the battery module and the current temperature of the battery cell not close to the terminal block corresponding to the battery module is greater than a preset temperature difference, and the difference increases as the current of the battery module increases; the battery cell close to the terminal block corresponding to the battery module is the battery cell closest to the terminal block corresponding to the battery module.

[0029] The eighth preset condition includes that the DC internal resistance of the battery module is greater than the preset internal resistance value, and that the discharge capacity of the battery module in the low current discharge state is greater than the preset discharge capacity.

[0030] Secondly, embodiments of the present invention provide a battery system, including: at least one battery cluster; the battery cluster includes multiple battery modules, and the battery modules are connected in series or in parallel.

[0031] The battery module includes a battery pack and a DC-DC converter module for charging and discharging the battery pack;

[0032] Any one of the battery pack, battery module, battery cluster, and battery system as a battery unit shall be used to perform thermal runaway alarm by employing the battery thermal runaway alarm method as described in the first aspect or any possible implementation thereof.

[0033] In one possible implementation, the battery system also includes a module-level controller (PBMU) corresponding to each battery module and a pack-level controller (BMU) corresponding to each battery pack.

[0034] When the parameter information is at least one of temperature change information and voltage change information, the BMU executes the battery thermal runaway alarm method as described in the first aspect or any possible implementation of the first aspect to perform a thermal runaway alarm.

[0035] When the parameter information is at least one of trigger protection information and output association information, the PBMU executes the battery thermal runaway alarm method as described in the first aspect or any possible implementation of the first aspect to perform a thermal runaway alarm.

[0036] This invention provides a battery thermal runaway alarm method and battery system. When the current state of the fault diagnosis state machine is in an abnormal operating state, if at least one of the following is detected as abnormal: battery temperature change information, voltage change information, trigger protection information, and output association information, a thermal runaway alarm for the battery cell is triggered. This allows for thermal runaway alarms to be triggered even when the battery cell's parameter information is abnormal, even after the battery cell has been controlled accordingly, in order to alert personnel that thermal runaway may still occur and prevent damage to the battery cell. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a schematic flowchart of the battery thermal runaway alarm method provided in an embodiment of the present invention;

[0039] Figure 2 This is a schematic diagram of the battery system provided in an embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram of the battery thermal runaway alarm device provided in an embodiment of the present invention;

[0041] Figure 4 This is a schematic diagram of the control device provided in an embodiment of the present invention. Detailed Implementation

[0042] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0043] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments will be described below in conjunction with the accompanying drawings.

[0044] See Figure 1 The diagram illustrates the implementation flowchart of the battery thermal runaway alarm method provided in this embodiment of the invention. The battery thermal runaway alarm method includes:

[0045] In S101, the current state of the fault diagnosis state machine is obtained; the fault diagnosis state machine is used to diagnose faults in the battery cells and switch states based on the fault diagnosis results.

[0046] Here, "battery cell" does not refer to a specific level of battery. It can be a system-level battery (i.e., a battery system); a cluster-level battery (i.e., a battery cluster); a module-level battery (i.e., a battery module); a pack-level battery (i.e., a battery pack); or a cell-level battery (i.e., a cell), and so on. The relationships between these levels can be found in the subsequent descriptions of battery systems.

[0047] The battery unit can be a lithium battery unit or a rechargeable battery unit; no specific restrictions are made here.

[0048] In this embodiment, the fault diagnosis state machine can diagnose faults in the battery cells and switch states accordingly when a fault is detected. The battery cell control device can control the battery cell based on the current state of the fault diagnosis state machine. For example, if the current state of the fault diagnosis state machine is "charge prohibited," the battery cell is prevented from charging; if the current state of the fault diagnosis state machine is "discharge prohibited," the battery cell is prevented from discharging; if the current state of the fault diagnosis state machine is "fault-triggered power-off," the battery cell is powered off, and so on.

[0049] For example, when the battery cell temperature is too high, the state of the fault diagnosis state machine can be switched to an abnormal operation state. For instance, it can be switched to a charging-prohibited state, a discharging-prohibited state, or a fault-power-off state based on the state of the battery cell. Thus, the battery cell control device can perform corresponding control on the battery cell to reduce the temperature of the battery cell.

[0050] This embodiment can determine the current state of the battery cell by obtaining the current state of the fault diagnosis state machine.

[0051] In S102, if the current state of the fault diagnosis state machine is an abnormal operation state, the parameter information of the battery cell is obtained; wherein, the abnormal operation state includes at least one of the charging-prohibited state, the discharging-prohibited state, and the fault-powered state, and the parameter information includes at least one of the temperature change information, voltage change information, trigger protection information, and output association information.

[0052] "Charging prohibited" means charging is prohibited. "Discharging prohibited" means discharging is prohibited. "Fault-triggered power-off" means power-off is triggered due to a fault.

[0053] The parameter information of the battery cell may include at least one of the following: battery cell temperature change information, battery cell voltage change information, battery cell trigger protection information, and battery cell output correlation information. Specifically, battery cell temperature change information can be understood as information related to changes in the battery cell's temperature; battery cell voltage change information can be understood as information related to changes in the battery cell's voltage; battery cell trigger protection information can be understood as information related to the battery cell's protection triggering; and battery cell output correlation information can be understood as information related to the battery cell's output.

[0054] When the current state of the fault diagnosis state machine is an abnormal state such as a no-charge state, no-discharge state, or fault-powered state, it indicates that the battery cell has a corresponding fault (e.g., overheating). In this case, the battery cell control device will perform corresponding control on the battery cell based on the current state of the fault diagnosis state machine to resolve the corresponding fault. However, in practical applications, it has been found that even after performing corresponding control on the battery cell based on the current state of the fault diagnosis state machine, thermal runaway may still occur. Therefore, to detect this thermal runaway phenomenon in a timely manner, this embodiment acquires the battery cell's parameter information when the current state of the fault diagnosis state machine is an abnormal operating state, so as to determine whether thermal runaway exists based on the battery cell's parameter information and issue an alarm.

[0055] In this embodiment, the parameter information of the battery cell is all related to the determination of thermal runaway.

[0056] In S103, if there is an abnormality in the parameter information of the battery cell, a thermal runaway alarm for the battery cell will be triggered.

[0057] If the current state of the fault diagnosis state machine is an abnormal operating state, and the parameter information of the battery cell is still abnormal, a thermal runaway alarm for the battery cell will be issued to remind the staff that the battery cell is at risk of thermal runaway. The staff can then take certain measures to avoid damaging the battery cell.

[0058] In this embodiment, when the current state of the fault diagnosis state machine is in an abnormal operating state, if at least one of the following is detected as abnormal: battery temperature change information, voltage change information, trigger protection information, and output association information, a thermal runaway alarm for the battery unit is triggered. Thus, even when the current state of the fault diagnosis state machine is in an abnormal operating state and the battery unit has been controlled accordingly, a thermal runaway alarm can still be triggered when the parameter information of the battery unit is abnormal, so as to remind the staff that the battery unit is still in a state of thermal runaway and avoid damage to the battery unit.

[0059] In some embodiments, in the above S103, the abnormality of the parameter information of the battery cell includes at least one of the following: the temperature change information of the battery cell meets a first preset condition, the voltage change information of the battery cell meets a second preset condition, the trigger protection information of the battery cell meets a third preset condition, and the output association information of the battery cell meets a fourth preset condition.

[0060] In some embodiments, the temperature change information of the battery cell includes the current temperature of the battery cell and the current temperature rise rate; the first preset condition includes that the current temperature of the battery cell is greater than the preset temperature corresponding to the battery cell, and the current temperature rise rate of the battery cell is greater than the first temperature rise rate threshold corresponding to the battery cell.

[0061] The battery change information of the battery cell includes the current voltage of the battery cell and the current voltage change trend; the second preset condition includes that the current voltage of the battery cell is greater than the preset voltage corresponding to the battery cell, and the current voltage change trend of the battery cell is an upward trend.

[0062] The battery cell's trigger protection information includes whether the battery cell has triggered overvoltage protection and the battery cell's current SOC (State of Charge). The third preset condition includes the battery cell triggering overvoltage protection and the absolute value of the difference between the battery cell's current SOC and its theoretical SOC being greater than the first preset difference corresponding to the battery cell.

[0063] The battery cell's output-related information includes the battery cell's current output current and the battery cell's relay fault reporting information; the fourth preset condition includes the battery cell's current output current being 0 and the battery cell's relay fault reporting information being a non-reported relay sticking fault; the battery cell's relay is used to connect the battery cell and the charging / discharging device.

[0064] It should be noted that the preset temperature, the first temperature rise rate threshold, the preset voltage, and the first preset difference of the battery cell can be changed according to the different battery levels. These settings can be made according to actual needs and are not specifically limited here.

[0065] When the battery cell temperature is too high and the fault diagnosis state machine switches to an abnormal state, the battery cell control device can theoretically control the battery cell temperature to decrease by performing corresponding control.

[0066] However, if the current temperature of the battery cell is detected to be higher than the preset temperature of the battery cell (temperature too high), and the current temperature rise rate of the battery cell is higher than the first temperature rise rate threshold of the battery cell (temperature continues to rise), it indicates that the battery cell is at risk of thermal runaway and a thermal runaway alarm needs to be issued.

[0067] From a voltage perspective, excessively high voltage can also cause temperature to rise. If the current voltage of the battery cell is detected to be greater than the preset voltage corresponding to the battery cell, and the current voltage of the battery cell shows an upward trend, it indicates that the battery cell is at risk of thermal runaway and a thermal runaway alarm needs to be issued.

[0068] When the current voltage of the battery cell exceeds the corresponding preset voltage, the battery cell triggers overvoltage protection. At this time, the theoretical SOC of the battery cell should be 100%. The current SOC of the battery cell is calculated based on some current information of the battery cell. If the absolute value of the difference between the current SOC and the theoretical SOC of the battery cell is too large, exceeding the first preset difference, it indicates that the battery cell has a risk of thermal runaway and a thermal runaway alarm needs to be issued.

[0069] The battery cell is connected to the charging and discharging equipment via a relay. When the current output current of the battery cell is detected to be 0, and the fault report information of the battery cell's relay is "no relay sticking fault reported", it indicates that the battery cell has a risk of thermal runaway and a thermal runaway alarm needs to be issued.

[0070] In some embodiments, in S103 above, the thermal runaway alarm of the battery cell is performed, including:

[0071] Based on the parameter information of the battery cell and the parameter information of each first battery cell located around the battery cell, the thermal runaway type of the battery cell is determined, and a corresponding alarm is issued according to the thermal runaway type of the battery cell. The thermal runaway type includes thermal runaway propagation and individual thermal runaway.

[0072] Thermal runaway in battery cells can be categorized into two types: thermal runaway propagation and isolated thermal runaway. Isolated thermal runaway refers to a situation where a single battery cell experiences thermal runaway without affecting other battery cells. Thermal runaway propagation, on the other hand, occurs when the thermal runaway of a single battery cell causes surrounding battery cells to also experience temperature increases, posing a risk of thermal runaway.

[0073] In this embodiment, other battery cells located around the battery cell are referred to as first battery cells. First battery cells are adjacent to the battery cell in position, and there are no other battery cells separating the first battery cells from the battery cell. The number of first battery cells is variable and can be determined based on the actual positional relationship of each battery cell.

[0074] This embodiment can determine the thermal runaway type of the battery cell based on the parameter information of the battery cell and the parameter information of each first battery cell, and issue an alarm corresponding to the thermal runaway type of the battery cell, so that the staff can know the thermal runaway type of the battery cell and take measures corresponding to the thermal runaway type.

[0075] In some embodiments, the parameter information of the battery cell includes the current temperature rise rate of the battery cell; the parameter information of the first battery cell includes the current temperature rise rate of the first battery cell.

[0076] The above-mentioned determination of the thermal runaway type of the battery cell based on the parameter information of the battery cell and the parameter information of each first battery cell located around the battery cell includes:

[0077] If the current temperature rise rate of the battery cell is greater than the second temperature rise rate threshold, and there is a first battery cell in each first battery cell whose current temperature rise rate is greater than the third temperature rise rate threshold, then the thermal runaway type of the battery cell is determined to be thermal runaway propagation; otherwise, the thermal runaway type of the battery cell is determined to be isolated thermal runaway.

[0078] Among them, the second temperature rise rate threshold is greater than the third temperature rise rate threshold.

[0079] The second and third temperature rise rate thresholds can be set according to actual needs, and no specific restrictions are imposed here.

[0080] When the current temperature rise rate of a battery cell is detected to be greater than the second temperature rise rate threshold, and there is a first battery cell around it with a current temperature rise rate greater than the third temperature rise rate threshold, that is, when the battery cell is rising in temperature at a certain rate and there is a first battery cell around it with a temperature rise rate slightly lower than the current temperature rise rate of the battery cell, it is determined that thermal runaway propagation has occurred in the battery cell; otherwise, it is considered that the battery cell has not experienced thermal runaway propagation, and its thermal runaway type is isolated thermal runaway.

[0081] In some embodiments, the above-described battery thermal runaway alarm method further includes:

[0082] Based on the parameter information of the battery module containing each battery cell and the parameter information of each battery cell contained in the battery module, it is determined whether there is a loose connection fault in the terminal block corresponding to the battery module, and a corresponding alarm is issued when there is a loose connection fault in the terminal block corresponding to the battery module; wherein, each battery cell in the battery module is connected through the terminal block corresponding to the battery module.

[0083] In this embodiment, the level above the battery cell is referred to as the battery module. Each battery cell within the battery module is connected via a corresponding terminal block. In actual use, this terminal block may become loose, affecting the performance of the battery module and its individual battery cells. Therefore, this embodiment uses the parameter information of the battery module and the parameter information of each battery cell within the module to determine whether there is a loose connection fault in the terminal block corresponding to the battery module. When a loose connection fault is detected, a corresponding alarm is triggered, allowing personnel to promptly resolve the issue and prevent further impact on the performance of the battery module and its individual battery cells.

[0084] In some embodiments, the parameter information of the battery module includes the current voltage, DC internal resistance, and discharge capacity in a low-current discharge state; the battery module is in a low-current discharge state when the discharge current is less than a preset discharge current.

[0085] The battery cell's parameter information includes the battery cell's current voltage, current temperature, and current rate of temperature rise;

[0086] The above-mentioned method, based on the parameter information of the battery module containing each battery cell and the parameter information of each battery cell contained in the battery module, determines whether there is a loose connection fault in the terminal block corresponding to the battery module, including:

[0087] If at least one of the following conditions is met: the current voltage of the battery module and the current voltage of each battery cell meet the fifth preset condition; the current temperature rise rate of each battery cell meets the sixth preset condition; the current temperature of each battery cell meets the seventh preset condition; and the DC internal resistance of the battery module and the discharge capacity of the battery module in the low current discharge state meet the eighth preset condition, then it is determined that there is a loose connection fault in the terminal block corresponding to the battery module.

[0088] The preset discharge current can be set according to actual needs, for example, it can be 0.1C, where C is the rated capacity of the battery module.

[0089] The discharge capacity of a battery module under low-current discharge conditions can be understood as the total amount of electricity that the battery module can release under low-current discharge conditions. More specifically, it can be understood as the total amount of electricity that the battery module can release through low-current discharge when it is fully charged.

[0090] In some embodiments, the fifth preset condition includes: the battery cells are connected in series and the absolute value of the difference between the sum of the current voltages of the battery cells in the battery module and the current voltage of the battery module is greater than or equal to the first preset voltage difference; or, the battery cells are connected in parallel and the absolute value of the difference between the current voltage of at least one battery cell in the battery module and the current voltage of the battery module is greater than or equal to the second preset voltage difference.

[0091] The sixth preset condition includes that the current temperature rise rate of at least one battery cell in the battery module is greater than the fourth temperature rise rate threshold.

[0092] The seventh preset condition includes that the difference between the current temperature of the battery cell close to the terminal block corresponding to the battery module and the current temperature of the battery cell not close to the terminal block corresponding to the battery module is greater than a preset temperature difference, and the difference increases as the current of the battery module increases; the battery cell close to the terminal block corresponding to the battery module is the battery cell closest to the terminal block corresponding to the battery module.

[0093] The eighth preset condition includes that the DC internal resistance of the battery module is greater than the preset internal resistance value, and that the discharge capacity of the battery module in the low current discharge state is greater than the preset discharge capacity.

[0094] When the battery cells in a battery module are connected in series, the sum of the current voltages of all the battery cells in the module should be equal to or substantially equal to the current voltage of the battery module (i.e., the difference should be small). When the battery cells in a battery module are connected in parallel, the current voltage of each battery cell in the module should be equal to or substantially equal to the battery voltage of the module. If the above conditions are not met, it can be considered that there is a loose connection fault in the terminal block of the battery module. The first and second preset voltage difference values ​​can be set according to actual needs and are not specifically limited here.

[0095] When a connection fault occurs at the battery module's terminal block, the battery cells within the module may experience a temperature rise. Therefore, the presence of a loose connection at the battery module's terminal block can be determined by detecting whether the current temperature rise rate of any battery cell exceeds a fourth temperature rise rate threshold. The fourth temperature rise rate threshold can be set according to actual needs and is not specifically limited here.

[0096] If there is a loose connection at the battery module's terminal block, a temperature difference will exist between the battery cells closer to the corresponding terminal block and those not close during charging and discharging. This temperature difference increases with the battery module's current. Therefore, the presence of a loose connection at the battery module's terminal block can be determined by detecting whether the difference between the current temperature of the battery cells closer to the corresponding terminal block and those not closer exceeds a preset temperature difference, and whether this difference increases with the battery module's current. The preset temperature difference can be set according to actual needs and is not specifically limited here.

[0097] If there is no loose connection fault in the battery module's terminal block, the battery module's DC internal resistance is relatively low at the factory. When the battery module's discharge capacity under low current conditions is less than the preset discharge capacity, the battery module's DC internal resistance will increase, exceeding the preset internal resistance value. Therefore, if the battery module's discharge capacity under low current conditions is greater than the preset internal resistance value, and the battery module's discharge capacity is greater than the preset discharge capacity, then there is a loose connection fault in the Ouming battery module's terminal block. The preset internal resistance value and preset discharge capacity can be set according to actual needs. For example, the preset internal resistance value can be twice the battery module's factory DC internal resistance, and the preset discharge capacity can be 80% of the battery module's rated capacity.

[0098] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0099] For the battery thermal runaway alarm method described above, please refer to [link / reference]. Figure 2 This application also provides a battery system, including at least one battery cluster 21; the battery cluster 21 includes a plurality of battery modules 22, which are connected in series or in parallel.

[0100] The battery module 22 includes a battery pack 23 and a DC / DC converter module 24 for charging and discharging the battery pack 23;

[0101] The battery pack 23, battery module 22, battery cluster 21 and any one of the battery system can be used as a battery unit to perform thermal runaway alarm using any of the above battery thermal runaway alarm methods.

[0102] The battery pack 23 may include multiple cells connected in series or in parallel.

[0103] In some embodiments, see Figure 2 The battery system also includes a module-level controller PBMU corresponding to each battery module 22 and a pack-level controller BMU corresponding to each battery pack 23.

[0104] When the parameter information is at least one of temperature change information and voltage change information, the BMU executes any of the above battery thermal runaway alarm methods to perform a thermal runaway alarm.

[0105] When the parameter information is at least one of the trigger protection information and output association information, the PBMU executes any of the above battery thermal runaway alarm methods to issue a thermal runaway alarm.

[0106] See also some possible implementations. Figure 2 The battery system may also include a cluster-level controller (SBMU) corresponding to each battery cluster 21. The SBMU can be used for cluster-level charge and discharge management, module data acquisition, storage and forwarding of important fault alarms, and cluster-level SOC calculation, etc. The battery system output can power a UPS (Uninterruptible Power Supply), and the SBMU can exchange information with the UPS. The SBMU can also interact with users via a touchscreen or other means. The SBMU can also exchange information with the cloud.

[0107] The BMU can be used to collect parameters such as voltage and temperature of each cell in the battery pack 23, perform equalization management of each cell, judge abnormal conditions such as overvoltage, undervoltage, overtemperature, undertemperature, and imbalance of each cell, and report the collected information and / or judgment results to the corresponding PBMU.

[0108] The PBMU can collect information reported by the corresponding BMU, and combine it with information such as the total voltage and total current of the battery module 22 to estimate SOC and SOH. It can also collect and summarize the status / parameters of the corresponding DC-DC converter module 24 and upload them to the SBMU. The PBMU can also perform corresponding charge / discharge control, power-on / off control, etc., according to the instructions issued by the SBMU.

[0109] In this embodiment, when the parameter information of the battery cell is at least one of temperature change information and voltage change information, the BMU can execute the above-described battery thermal runaway alarm method. When the parameter information of the battery cell is at least one of trigger protection information and output association information, the PBMU can execute the above-described battery thermal runaway alarm method.

[0110] In some possible implementations, regardless of the type of information included in the battery cell parameters, the above-mentioned battery thermal runaway alarm methods can all be executed in the BMU or in the PBMU; no specific restrictions are imposed here.

[0111] The following are device embodiments of the present invention. For details not described in detail, please refer to the corresponding method embodiments described above.

[0112] Figure 3 A schematic diagram of the battery thermal runaway alarm device provided in an embodiment of the present invention is shown. For ease of explanation, only the parts related to the embodiment of the present invention are shown, and are described in detail below:

[0113] like Figure 3 As shown, the battery thermal runaway alarm device 30 may include: a status determination module 31, a parameter acquisition module 32, and an alarm module 33.

[0114] The state determination module 31 is used to obtain the current state of the fault diagnosis state machine; the fault diagnosis state machine is used to diagnose faults in the battery cells and switch states based on the fault diagnosis results.

[0115] The parameter acquisition module 32 is used to acquire the parameter information of the battery cell if the current state of the fault diagnosis state machine is an abnormal operation state; wherein, the abnormal operation state includes at least one of the charging-prohibited state, the discharging-prohibited state, and the fault power-off state, and the parameter information includes at least one of the temperature change information, voltage change information, trigger protection information, and output association information.

[0116] The thermal runaway alarm module 33 is used to issue a thermal runaway alarm for the battery cell if there is an abnormality in the parameter information of the battery cell.

[0117] In one possible implementation, in the thermal runaway alarm module 33, the abnormality of the battery cell parameter information includes at least one of the following: the battery cell temperature change information meets a first preset condition, the battery cell voltage change information meets a second preset condition, the battery cell trigger protection information meets a third preset condition, and the battery cell output association information meets a fourth preset condition.

[0118] In one possible implementation, in the thermal runaway alarm module 33, the temperature change information of the battery cell includes the current temperature of the battery cell and the current temperature rise rate; the first preset condition includes that the current temperature of the battery cell is greater than the preset temperature corresponding to the battery cell, and the current temperature rise rate of the battery cell is greater than the first temperature rise rate threshold corresponding to the battery cell.

[0119] The battery change information of the battery cell includes the current voltage of the battery cell and the current voltage change trend; the second preset condition includes that the current voltage of the battery cell is greater than the preset voltage corresponding to the battery cell, and the current voltage change trend of the battery cell is an upward trend.

[0120] The battery cell's trigger protection information includes whether the battery cell has triggered overvoltage protection and the current SOC of the battery cell; the third preset condition includes the battery cell triggering overvoltage protection and the absolute value of the difference between the current SOC of the battery cell and the theoretical SOC of the battery cell being greater than the first preset difference corresponding to the battery cell.

[0121] The battery cell's output-related information includes the battery cell's current output current and the battery cell's relay fault reporting information; the fourth preset condition includes the battery cell's current output current being 0 and the battery cell's relay fault reporting information being a non-reported relay sticking fault; the battery cell's relay is used to connect the battery cell and the charging / discharging device.

[0122] In one possible implementation, the thermal runaway alarm module 33 performs a thermal runaway alarm for the battery cell, including:

[0123] Based on the parameter information of the battery cell and the parameter information of each first battery cell located around the battery cell, the thermal runaway type of the battery cell is determined, and a corresponding alarm is issued according to the thermal runaway type of the battery cell. The thermal runaway type includes thermal runaway propagation and individual thermal runaway.

[0124] In one possible implementation, in the thermal runaway alarm module 33, the parameter information of the battery cell includes the current temperature rise rate of the battery cell; the parameter information of the first battery cell includes the current temperature rise rate of the first battery cell.

[0125] Based on the parameter information of the battery cell and the parameter information of each first battery cell located around the battery cell, the thermal runaway type of the battery cell is determined, including:

[0126] If the current temperature rise rate of the battery cell is greater than the second temperature rise rate threshold, and there is a first battery cell in each first battery cell whose current temperature rise rate is greater than the third temperature rise rate threshold, then the thermal runaway type of the battery cell is determined to be thermal runaway propagation; otherwise, the thermal runaway type of the battery cell is determined to be isolated thermal runaway.

[0127] Among them, the second temperature rise rate threshold is greater than the third temperature rise rate threshold.

[0128] In one possible implementation, the battery thermal runaway alarm device 30 further includes a loosening alarm module.

[0129] The loose connection alarm module is used to: determine whether there is a loose connection fault in the terminal block corresponding to the battery module based on the parameter information of the battery module containing each battery cell and the parameter information of each battery cell contained in the battery module, and to issue a corresponding alarm when there is a loose connection fault in the terminal block corresponding to the battery module; wherein, each battery cell in the battery module is connected through the terminal block corresponding to the battery module.

[0130] In one possible implementation, the battery module's parameter information in the loosening alarm module includes the battery module's current voltage, DC internal resistance, and discharge capacity in a low-current discharge state; the battery module is in a low-current discharge state when the discharge current is less than the preset discharge current.

[0131] The battery cell's parameter information includes the battery cell's current voltage, current temperature, and current rate of temperature rise;

[0132] Based on the parameter information of the battery module containing each battery cell and the parameter information of each battery cell contained in the battery module, determine whether there is a loose connection fault in the corresponding terminal block of the battery module, including:

[0133] If at least one of the following conditions is met: the current voltage of the battery module and the current voltage of each battery cell meet the fifth preset condition; the current temperature rise rate of each battery cell meets the sixth preset condition; the current temperature of each battery cell meets the seventh preset condition; and the DC internal resistance of the battery module and the discharge capacity of the battery module in the low current discharge state meet the eighth preset condition, then it is determined that there is a loose connection fault in the terminal block corresponding to the battery module.

[0134] In one possible implementation, in the loosening alarm module, the fifth preset condition includes: the battery cells are connected in series and the absolute value of the difference between the sum of the current voltages of the battery cells in the battery module and the current voltage of the battery module is greater than or equal to a first preset voltage difference; or, the battery cells are connected in parallel and the absolute value of the difference between the current voltage of at least one battery cell in the battery module and the current voltage of the battery module is greater than or equal to a second preset voltage difference.

[0135] The sixth preset condition includes that the current temperature rise rate of at least one battery cell in the battery module is greater than the fourth temperature rise rate threshold.

[0136] The seventh preset condition includes that the difference between the current temperature of the battery cell close to the terminal block corresponding to the battery module and the current temperature of the battery cell not close to the terminal block corresponding to the battery module is greater than a preset temperature difference, and the difference increases as the current of the battery module increases; the battery cell close to the terminal block corresponding to the battery module is the battery cell closest to the terminal block corresponding to the battery module.

[0137] The eighth preset condition includes that the DC internal resistance of the battery module is greater than the preset internal resistance value, and that the discharge capacity of the battery module in the low current discharge state is greater than the preset discharge capacity.

[0138] Figure 4 This is a schematic diagram of the control device provided in an embodiment of the present invention. Figure 4 As shown, the control device 4 in this embodiment includes a processor 40 and a memory 41. The memory 41 stores a computer program 42, and the processor 40 calls and runs the computer program 42 stored in the memory 41 to execute the steps in the various battery thermal runaway alarm method embodiments described above, for example... Figure 1 S101 to S103 are shown. Alternatively, the processor 40 is used to call and run the computer program 42 stored in the memory 41 to implement the functions of each module / unit in the above-described device embodiments, for example... Figure 3 The functions of modules / units 31 to 33 shown.

[0139] For example, the computer program 42 can be divided into one or more modules / units, which are stored in the memory 41 and executed by the processor 40 to complete the present invention. The one or more modules / units can be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program 42 in the control device 4. For example, the computer program 42 can be divided into... Figure 3 Modules / units 31 to 33 are shown.

[0140] The control device 4 may be a controller or control unit for each battery level. The control device 4 may include, but is not limited to, a processor 40 and a memory 41. Those skilled in the art will understand that... Figure 4 This is merely an example of control device 4 and does not constitute a limitation on control device 4. It may include more or fewer components than shown, or combine certain components, or different components. For example, the control device may also include input / output devices, network access devices, buses, etc.

[0141] The processor 40 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0142] The memory 41 can be an internal storage unit of the control device 4, such as a hard disk or memory of the control device 4. The memory 41 can also be an external storage device of the control device 4, such as a plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card equipped on the control device 4. Furthermore, the memory 41 can include both internal and external storage units of the control device 4. The memory 41 is used to store the computer program and other programs and data required by the control device. The memory 41 can also be used to temporarily store data that has been output or will be output.

[0143] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0144] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0145] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0146] In the embodiments provided by this invention, it should be understood that the disclosed apparatus / control devices and methods can be implemented in other ways. For example, the apparatus / control device embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0147] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0148] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0149] If the integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the above embodiments of the present invention can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various battery thermal runaway alarm method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc. It should be noted that the content contained in the computer-readable medium may be appropriately added to or subtracted from the content as required by the legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium may not include electrical carrier signals and telecommunication signals.

[0150] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A battery thermal runaway alert method, characterized in that, include: Obtain the current state of the fault diagnosis state machine; The fault diagnosis state machine is used to diagnose faults in battery cells and switch states based on the fault diagnosis results. If the current state of the fault diagnosis state machine is an abnormal operating state, then the parameter information of the battery cell is obtained; wherein, the abnormal operating state includes at least one of the following: charging-prohibited state, discharging-prohibited state, and fault power-off state, and the parameter information includes at least one of the following: temperature change information, voltage change information, trigger protection information, and output association information; If the parameter information of the battery cell is abnormal, a thermal runaway alarm for the battery cell will be triggered. Based on the parameter information of the battery module containing each of the battery cells and the parameter information of each of the battery cells contained in the battery module, it is determined whether there is a loose connection fault in the terminal block corresponding to the battery module, and a corresponding alarm is triggered when there is a loose connection fault in the terminal block corresponding to the battery module; wherein, each battery cell in the battery module is connected through the terminal block corresponding to the battery module. The parameter information of the battery module includes the DC internal resistance of the battery module and the discharge capacity in the low current discharge state; the battery module is in the low current discharge state when the discharge current is less than the preset discharge current; the parameter information of the battery cell includes the current temperature of the battery cell. The step of determining whether there is a loose connection fault in the terminal block corresponding to the battery module based on the parameter information of the battery module containing each of the battery cells and the parameter information of each of the battery cells contained in the battery module includes: If the current temperature of each battery cell meets the seventh preset condition and the DC internal resistance of the battery module and the discharge capacity of the battery module in the low current discharge state meet the eighth preset condition, then it is determined that there is a loose connection fault in the terminal block corresponding to the battery module. The seventh preset condition includes the difference between the current temperature of the battery cell close to the terminal block corresponding to the battery module and the current temperature of the battery cell not close to the terminal block corresponding to the battery module being greater than a preset temperature difference, and the difference increasing as the current of the battery module increases; the battery cell close to the terminal block corresponding to the battery module is the battery cell closest to the terminal block corresponding to the battery module. The eighth preset condition includes that the DC internal resistance of the battery module is greater than a preset internal resistance value, and that the discharge capacity of the battery module in a low-current discharge state is greater than a preset discharge capacity.

2. The battery thermal runaway alert method of claim 1, wherein, The abnormality of the parameter information of the battery cell includes at least one of the following: the temperature change information of the battery cell meets a first preset condition; the voltage change information of the battery cell meets a second preset condition; the trigger protection information of the battery cell meets a third preset condition; and the output association information of the battery cell meets a fourth preset condition.

3. The battery thermal runaway alarm method according to claim 2, characterized in that, The temperature change information of the battery cell includes the current temperature of the battery cell and the current temperature rise rate; the first preset condition includes that the current temperature of the battery cell is greater than the preset temperature corresponding to the battery cell, and the current temperature rise rate of the battery cell is greater than the first temperature rise rate threshold corresponding to the battery cell. The voltage change information of the battery cell includes the current voltage of the battery cell and the current voltage change trend; the second preset condition includes that the current voltage of the battery cell is greater than the preset voltage corresponding to the battery cell, and the current voltage change trend of the battery cell is an upward trend; The battery cell's trigger protection information includes whether the battery cell has triggered overvoltage protection and the current SOC of the battery cell; the third preset condition includes the battery cell triggering overvoltage protection and the absolute value of the difference between the current SOC of the battery cell and the theoretical SOC of the battery cell being greater than the first preset difference corresponding to the battery cell. The output association information of the battery cell includes the current output current of the battery cell and the fault reporting information of the relay of the battery cell; the fourth preset condition includes that the current output current of the battery cell is 0 and the fault reporting information of the relay of the battery cell is that no relay sticking fault is reported; the relay of the battery cell is used to connect the battery cell and the charging and discharging device.

4. The battery thermal runaway alarm method according to claim 1, characterized in that, The process of triggering a thermal runaway alarm for the battery cell includes: Based on the parameter information of the battery cell and the parameter information of each first battery cell located around the battery cell, the thermal runaway type of the battery cell is determined, and a corresponding alarm is issued according to the thermal runaway type of the battery cell. The thermal runaway type includes thermal runaway propagation and individual thermal runaway.

5. The battery thermal runaway alarm method according to claim 4, characterized in that, The parameter information of the battery cell includes the current temperature rise rate of the battery cell; the parameter information of the first battery cell includes the current temperature rise rate of the first battery cell. Determining the thermal runaway type of the battery cell based on the parameter information of the battery cell and the parameter information of each first battery cell located around the battery cell includes: If the current temperature rise rate of the battery cell is greater than the second temperature rise rate threshold, and there is a first battery cell in each of the first battery cells whose current temperature rise rate is greater than the third temperature rise rate threshold, then the thermal runaway type of the battery cell is determined to be thermal runaway propagation; otherwise, the thermal runaway type of the battery cell is determined to be isolated thermal runaway. Wherein, the second temperature rise rate threshold is greater than the third temperature rise rate threshold.

6. A battery system, characterized in that, It includes at least one battery cluster; the battery cluster includes multiple battery modules, and the battery modules are connected in series or in parallel. The battery module includes a battery pack and a DC-DC converter module for charging and discharging the battery pack; The battery pack, the battery module, the battery cluster, and any one of the battery systems are used as battery units, and thermal runaway alarm is performed using the battery thermal runaway alarm method as described in any one of claims 1 to 5.

7. The battery system according to claim 6, characterized in that, The battery system also includes a module-level controller (PBMU) corresponding to each battery module and a pack-level controller (BMU) corresponding to each battery pack. When the parameter information of the battery cell is at least one of temperature change information and voltage change information, the BMU executes the battery thermal runaway alarm method as described in any one of claims 1 to 5 to perform a thermal runaway alarm. When the parameter information of the battery cell is at least one of trigger protection information and output association information, the PBMU executes the battery thermal runaway alarm method as described in any one of claims 1 to 5 to perform a thermal runaway alarm.

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