Battery fire extinguishing system, battery thermal runaway uninterruptible power control method and automobile

Abstract

The invention discloses a battery fire extinguishing system, a battery thermal runaway uninterruptible power control method and an automobile, the battery fire extinguishing system comprises a box body, fire extinguishing equipment, a battery management system and a battery pack arranged in the box body and composed of a plurality of battery cells, the fire extinguishing equipment is filled with a fire inhibitor, and the fire extinguishing equipment is communicated with the interior of the box body; the battery management system is used for monitoring state parameters of the battery cell; a detection device is also arranged in the box body; the battery management system and / or the detector are / is used for controlling the fire extinguishing equipment to be started when it is judged that preset spraying conditions are met based on the monitored parameters, and the fire inhibitor is sprayed into the box body. By monitoring the battery cell state parameters and the environmental parameters in the box body, the fire extinguishing equipment is controlled to blow out the fire inhibitor when the blow-out condition is met, thermal runaway spreading is effectively prevented, and power failure of the whole vehicle is avoided.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of battery safety, and particularly relates to a battery fire extinguishing system, a battery thermal runaway continuous power control method and an automobile. BACKGROUND

[0002] In existing electric vehicle applications, after a battery pack thermal runaway event occurs, the battery management system usually triggers an alarm and forcibly disconnects the high-voltage relay, causing the vehicle to lose power. This power-off mechanism causes the vehicle to lose driving ability instantaneously, and in high-speed working conditions such as highways, the vehicle suddenly losing speed can easily cause rear-end accidents, seriously threatening the safety of drivers and other road users. At the same time, after power-off, the cooling system relying on electricity such as electric compressors stops working and cannot provide active cooling for the overheated battery cells, and can only rely on the slow natural cooling process, causing the battery pack to be in a high-temperature dangerous state for a long time, prolonging the risk period of thermal runaway spread. Thermal runaway, as a sudden event, is random and can occur in extreme environments such as cold regions, high-temperature regions, or remote suburbs. In these scenarios, the vehicle cannot provide basic energy support after power-off, and personnel can be stranded in harsh weather, lacking the necessary temperature regulation, communication, or mobility, and facing life safety threats.

[0003] In view of the above problems, the prior art needs to be improved. SUMMARY

[0004] The purpose of the present application is to solve the problems in the background art, and to provide a battery fire extinguishing system, a battery thermal runaway continuous power control method and an automobile, which can start fire extinguishing measures in time in the event of battery thermal runaway, avoid vehicle power-off, reduce the risk of vehicle stalling, ensure the continuous operation of the cooling system, reduce the probability of thermal runaway spread, and improve the safety of drivers and road users.

[0005] The technical scheme adopted by the present application is: a battery fire extinguishing system, comprising a box body, a fire extinguishing device, a battery management system and a battery pack composed of a plurality of battery cells arranged in the box body, The fire extinguishing device is filled with a fire suppressant, and the fire extinguishing device is in communication with the inside of the box body. The battery management system is used to monitor the state parameters of the battery cells. The box body is also provided with a detection device for monitoring the environmental parameters in the box body. The battery management system and / or the detector are used to determine, based on the monitored parameters, when the preset spraying conditions are met, to control the fire extinguishing device to start and spray the fire suppressant into the box body.

[0006] Further, the fire extinguishing device comprises a fire extinguishing bottle group and a fire extinguishing pipeline, the fire extinguishing bottle group is filled with fire extinguishing agent, and the fire extinguishing pipeline is connected with the fire extinguishing bottle group and a spray head arranged in the box.

[0007] Further, the preset spraying condition comprises: The battery management system determines a thermal runaway early warning according to the state parameter of the battery cell; or The environmental parameter monitored by the detector reaches a preset fault alarm threshold. The environmental parameter comprises at least one of smoke concentration, carbon monoxide concentration and temperature.

[0008] A battery thermal runaway uninterrupted power supply control method based on the above battery fire extinguishing system, comprising the following steps: determining whether the condition of entering the thermal runaway uninterrupted power supply mode is met; if the condition of entering the thermal runaway uninterrupted power supply mode is met, executing the thermal runaway uninterrupted power supply mode; continuously monitoring the state of the battery pack, and exiting the thermal runaway uninterrupted power supply mode when the preset exit condition is met.

[0009] Further, the condition of entering the thermal runaway uninterrupted power supply mode comprises: the battery management system determines a thermal runaway early warning and / or the environmental parameter monitored by the detector reaches a preset fault alarm threshold; and the fire extinguishing device sprays fire extinguishing agent.

[0010] Further, the execution of the thermal runaway uninterrupted power supply mode comprises: limiting the charging and discharging power of the battery pack, and requesting the highest level of battery cooling demand. The limited charging and discharging power is 1 / 5 of the rated charging and discharging power, and the requested highest level of cooling demand is the maximum compressor refrigeration capacity, the lowest water inlet temperature and the maximum liquid cooling flow.

[0011] Further, the preset exit condition comprises at least one of the following: (1) any high-voltage component of the vehicle has an insulation fault; (2) the total pressure of the battery pack is abnormal; (3) the duration of the thermal runaway uninterrupted power supply mode reaches a preset threshold; (4) the overall state of charge of the battery pack is lower than a preset value; (5) the battery pack has no current output response; (6) there is a fault that needs to be powered off, including at least one of thermal control fault, extreme under-voltage fault and vehicle collision fault; (7) on the basis of the limited charging and discharging power, there is a fault that needs to further limit the charging and discharging power. (8) the actual voltage of the battery cell that does not occur thermal runaway but sampling is offline abnormally decreases; (9) the actual voltage of the battery cell that does not occur thermal runaway but sampling is offline is normal, and the environmental parameter monitored by the detection device reaches the preset fault alarm threshold.

[0012] Further, when the total voltage of the battery pack satisfies: U v ≥(L-N)×U d , it is determined that the total voltage of the battery pack is abnormal, wherein U v is the total voltage of the battery pack; L is the total number of battery cells in the battery pack; N is the number of battery cells that occur thermal runaway in the battery pack; U d is the current dynamic voltage, which is obtained according to the temperature of the battery cell corresponding to the minimum SOC in the normal battery cell.

[0013] Still further, determining that the actual voltage abnormally decreases or is normal comprises: calculating the theoretical voltage U1 of the battery cell that does not occur thermal runaway but sampling is offline: U1=(L-N-M)×U d ; calculating the actual voltage U2 of the battery cell that does not occur thermal runaway but sampling is offline: U2=U v -(N+M)×U d ; if U1=0, it is determined that the actual voltage is normal; if U1>0, U1 and U2 are compared, when (U1-U2) / U2≥A and the duration is set, it is determined that the actual voltage abnormally decreases, otherwise it is determined that the actual voltage is normal; wherein L is the total number of battery cells in the battery pack; N is the number of battery cells that occur thermal runaway in the battery pack; M is the number of normal battery cells in the battery pack; U d is the current dynamic voltage, which is obtained according to the temperature of the battery cell corresponding to the minimum SOC in the normal battery cell; and A is a set decrease threshold.

[0014] A car comprises the battery fire extinguishing system as described above, and is configured to execute the thermal runaway uninterrupted power supply control method as described above.

[0015] The beneficial effects of the present application are: The present application monitors the state parameters of the battery cell and the environmental parameters in the box, controls the spraying of the fire extinguishing agent when the spraying condition is met, effectively prevents the spread of thermal runaway, avoids the power-off of the whole vehicle, thereby reduces the risk of vehicle breakdown, ensures the continuous work of the cooling system, reduces the probability of thermal runaway spread, and improves the safety of the driver and passengers and the road safety. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is the structure diagram of the battery fire extinguishing system of the present application.

[0017] Figure 2 The principle block diagram of the battery fire extinguishing system of the present application.

[0018] Figure 3 The schematic diagram of the preset fire extinguishing equipment spraying condition of the present application.

[0019] Figure 4 The schematic diagram of the condition of entering the thermal runaway continuous power mode of the present application.

[0020] Figure 5 The schematic diagram of the condition of exiting the thermal runaway continuous power mode of the present application.

[0021] In the figure, 1 - box; 1.1 - nozzle; 2 - battery cell; 3 - battery management system; 4 - fire extinguishing equipment; 4.1 - fire extinguishing bottle group; 4.2 - fire extinguishing pipeline; 5 - detection equipment; 6 - vehicle-mounted end. DETAILED DESCRIPTION

[0022] The present application will be further described below in conjunction with the accompanying drawings and specific embodiments, so as to make the present application clear. However, they do not constitute a limitation to the present application.

[0023] It should be understood that when used in the present application specification and the appended claims, the term "comprising" indicates the presence of the described features, whole, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, whole, steps, operations, elements, components and / or sets thereof.

[0024] In addition, the reference "one embodiment" or "some embodiments" and the like described in the present application specification means that the specific features, structures or characteristics described in conjunction with the embodiment are included in one or more embodiments of the present application. Therefore, the statements "in one embodiment", "in some embodiments", "in other some embodiments", "in other some embodiments" and the like appearing in the present specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized.

[0025] As Figures 1-2As shown, the present application proposes a battery fire extinguishing system, which includes a box 1, a fire extinguishing device 4, a battery management system 3, and a battery pack composed of several battery cells 2 arranged inside the box 1. The fire extinguishing device 4 is filled with fire suppressant and is in communication with the inside of the box 1. The battery management system 3 is used to monitor the state parameters of the battery cells, and the box 1 is also provided with a detection device 5 for monitoring the environmental parameters inside the box. Through the battery management system 3 and / or the detection device 4, the system can determine whether the preset spraying conditions are met based on the monitored parameters, and then control the fire extinguishing device 4 to start and spray the fire suppressant into the box 1, thereby addressing the battery thermal runaway problem.

[0026] For ease of understanding, some key terms in this embodiment are explained as follows: Box 1: refers to the external structure for containing the battery pack and related components, providing physical protection and environmental sealing.

[0027] Fire extinguishing device 4: refers to a device for releasing fire extinguishing medium to extinguish or suppress fire when it occurs, which is filled with fire suppressant inside.

[0028] Battery management system 3: abbreviated as BMS, used to manage the operation of rechargeable batteries, monitor their state parameters, and perform functions such as balancing and protection.

[0029] Battery cell 2: refers to the energy storage unit in the battery pack, which is combined in series and parallel to form the battery pack.

[0030] Battery pack: refers to a battery module integrated with multiple battery cells, thermal management systems, and other components, which is the energy source in electric vehicles or energy storage systems.

[0031] Fire suppressant: refers to a chemical substance or physical medium that can extinguish or suppress the spread of fire, such as aerosol, inert gas, or liquid fire extinguishing agent.

[0032] Detection device 5: refers to a sensor or device for monitoring environmental parameters inside the box, such as a smoke sensor, a carbon monoxide sensor, or a temperature sensor.

[0033] State parameters: refer to various physical quantities of the battery cells during operation, such as voltage, current, temperature, state of charge (SOC), etc.

[0034] Environmental parameters: refer to physical environmental indicators inside the battery pack box, such as smoke concentration, carbon monoxide concentration, temperature, etc.

[0035] Pre-set spraying conditions: refer to the conditions preset by the system to trigger the start of the fire extinguishing device and spray the fire suppressant, which are usually based on abnormal situations of battery cell state parameters and / or box environmental parameters.

[0036] The battery fire extinguishing system of the present application comprises a box, a fire extinguishing device, a battery management system and a battery pack composed of several battery cells arranged inside the box. The box can be made of metal material, composite material or engineering plastic, and its structure can be integrated or assembled by multiple parts, aiming to provide physical protection for the internal components. The battery pack is composed of multiple battery cells connected in series or parallel, and the type of battery cell can be cylindrical, square or soft package. The fire extinguishing device can be one or more pressure tanks filled with fire suppressant, which is triggered to release by mechanical or electric means. The battery management system can be a separate hardware unit or a software module integrated in the vehicle control unit, which functions to collect and process the operating data of the battery cells.

[0037] The fire suppressant can be selected from inert gas, aerosol or water-based fire extinguishing agent, etc., and the selection is based on the fire extinguishing efficiency and the impact on the battery components. The communication between the fire extinguishing device and the inside of the box can be achieved through pipes or flow guide structures, ensuring that the fire suppressant can be guided to the area where the battery pack is located.

[0038] The battery management system can collect the voltage, temperature of each battery cell and the current of the battery pack. The collection of these parameters can be achieved through sensors directly connected to the battery cells or through bus communication. The collected data is used to evaluate the state and operating condition of the battery cells.

[0039] The detection device can include one or more sensors, such as temperature sensors, humidity sensors or gas sensors. These sensors are arranged at important positions inside the box to obtain data of the internal environment of the box.

[0040] The battery management system and / or the detection device are used to determine when the preset spraying conditions are met based on the monitored parameters, and control the fire extinguishing device to start, spraying the fire suppressant into the box. The judgment logic can be based on threshold comparison of parameters, such as when the temperature of a certain battery cell exceeds the preset value, or when the temperature inside the box reaches the threshold value. The control of the fire extinguishing device to start can be triggered by sending an electrical signal to it, such as activating an electromagnetic valve or a mechanical actuator, so that the fire suppressant is released.

[0041] The battery fire extinguishing system of the present application can timely suppress the battery thermal runaway at the initial stage or when it occurs by monitoring the battery cell state parameters and the box environment parameters, and automatically controlling the fire extinguishing device to spray the fire suppressant based on the preset conditions. Thus, the vehicle can maintain operation in emergency situations. At the same time, the cooling capacity is maintained, preventing the duration of high temperature unsafe state from being prolonged. This provides protection for the vehicle in extreme working conditions, avoiding personnel from being trapped in dangerous environments due to power failure.

[0042] In one embodiment, the application further proposes that the fire extinguishing device 4 comprises a fire extinguishing bottle group 4.1 filled with fire suppression agent and a fire extinguishing pipeline 4.2 connecting the fire extinguishing bottle group 4.1 and the spray head 1.1 arranged inside the box body 1.

[0043] Specifically, the fire extinguishing bottle group 4.1 is a container for storing fire suppression agent, usually designed to withstand internal pressure and release the agent quickly when needed, which is generally installed on the vehicle-mounted end 6 near the battery pack. Its implementation can include but is not limited to: high-pressure gas cylinders, such as steel cylinders filled with clean extinguishing agents such as carbon dioxide, HFC-227ea (FM-200), or FK-5-1-12 (Novec1230); or using aerosol generators to generate fire-extinguishing aerosols through chemical reactions. The fire extinguishing bottle group as a storage unit of the agent is a key component to ensure that the agent is always available and can be efficiently sprayed.

[0044] The fire extinguishing pipeline 4.2 is a channel connecting the fire extinguishing bottle group 4.1 and the spray head 1.1, used to transport fire suppression agent from the storage unit to the target area. Its implementation can include but is not limited to: using pressure-resistant and corrosion-resistant metal pipes, such as stainless steel pipes or copper pipes, to ensure stable transportation in high-temperature or high-pressure environments; or using flexible high-pressure hoses to facilitate layout and connection in complex spaces. The design and material selection of the fire extinguishing pipeline directly affect the transportation efficiency of the agent and the reliability of the system.

[0045] The spray head is the final release component of the fire suppression agent, which is used to uniformly distribute the agent to the fire source area inside the box body in a specific way (such as atomization, injection, or diffusion). Its implementation can include but is not limited to: atomizing spray heads that can refine the agent into fine particles, improving coverage area and fire extinguishing efficiency; or direct spray heads that concentrate the agent and spray it to a specific area, suitable for rapid extinguishing of local fires. The number, type, and installation location of the spray head are crucial to ensure that the agent can effectively cover the battery pack and quickly suppress the fire.

[0046] By the technical solution, the specific structure of the fire extinguishing device is specified, the fire extinguishing bottle group serves as a reliable storage unit of the fire suppression agent, and the instant availability of the fire suppression agent is ensured. The fire extinguishing pipeline builds an efficient delivery path, and can rapidly deliver the fire suppression agent from the fire extinguishing bottle group to the inside of the box. The spray head arranged in the inside of the box can accurately and efficiently spray the fire suppression agent to the battery pack area, and directly act on the fire source. The specific structure design ensures that the fire suppression agent can timely and accurately cover and suppress the thermal runaway fire of the battery pack. Therefore, the fire can be quickly controlled, the high-voltage system of the whole vehicle is prevented from being powered off due to the spread of the fire, the vehicle can still continue to run in the thermal runaway early warning state, the vehicle is effectively prevented from stalling, valuable escape or rescue time is provided for the passengers, the cooling capacity of the battery pack is maintained, and the long-time continuation of the high-temperature unsafe state is avoided.

[0047] In one embodiment, the application further provides that the preset spraying condition includes that the battery management system determines that a thermal runaway early warning occurs according to the state parameters of the battery cell, or that the environment parameters monitored by the detector reach a preset fault alarm threshold, and the environment parameters include at least one of smoke concentration, carbon monoxide concentration and temperature. Figure 3

[0048] Specifically, the battery management system (BMS) continuously monitors the key operating parameters of each battery cell in the battery pack. These state parameters usually include but are not limited to the voltage, current, temperature, state of charge (SOC) and state of health (SOH) of the battery cell. When one or more of these parameters show abnormal change trends, such as rapid temperature rise, abnormal voltage drop, significant increase in internal resistance, etc., and these change trends meet the preset thermal runaway discrimination model or algorithm, the battery management system will issue a thermal runaway early warning. For example, it can be determined by monitoring whether the voltage drop rate or temperature rise rate of a single battery cell exceeds a certain threshold; or by analyzing the temperature gradient change between adjacent battery cells to predict the occurrence of thermal runaway.

[0049] At the same time, the detection device is used to monitor the environment parameters in the inside of the box in real time, so as to capture the external signs of the thermal runaway event. These detection devices can include a smoke sensor, a carbon monoxide sensor and a temperature sensor, etc. The smoke sensor is used to detect the concentration of smoke particles in the air in the inside of the box, the carbon monoxide sensor is used to detect the concentration of carbon monoxide gas, and the temperature sensor is used to monitor the overall environment temperature in the inside of the box. When any of the environment parameters (such as smoke concentration, carbon monoxide concentration or temperature) monitored by these detection devices reaches or exceeds the preset fault alarm threshold, it indicates that a thermal runaway event may have occurred or is occurring in the inside of the box, and immediate preventive measures are needed. At this time, the detection device reports the battery cell thermal runaway fault to the BMS. ​

[0050] By the technical solution, the preset spraying condition of starting the fire extinguishing device is determined, so that the fire extinguishing device can be started in time and accurately when the battery thermal runaway event occurs, and the problems of power failure and insufficient cooling of the vehicle are effectively avoided. Specifically, the battery management system determines the thermal runaway warning according to the state parameters of the battery cell, which allows early detection based on the internal state of the battery cell such as voltage or temperature, triggers the fire extinguishing response in advance, and prevents the thermal runaway from escalating into a more serious failure. At the same time, the environmental parameters monitored by the detection device reach the preset failure alarm threshold, and the environmental parameters include at least one of smoke concentration, carbon monoxide concentration and temperature, which provides a reliable confirmation mechanism by detecting actual signs of fire in the environment, such as smoke, carbon monoxide or temperature rise, to ensure that the fire extinguishing device is started in time when a fire occurs. This double judgment mechanism, on the one hand, realizes early warning through real-time monitoring of the internal state of the battery cell, and on the other hand, confirms and supplements through external monitoring of the box environment, significantly improves the response speed and judgment accuracy of the system to the thermal runaway event. When any condition is met, the fire extinguishing device is controlled to start, and the fire extinguishing agent is sprayed into the box, so as to quickly suppress the fire at the initial or spreading stage of the thermal runaway, minimize the damage to the battery pack, and ensure the continuous operation of the vehicle and the safety of the personnel.

[0051] In one embodiment, the application further provides a battery thermal runaway uninterrupted power supply control method, which comprises: judging whether the condition for entering the thermal runaway uninterrupted power supply mode is met; if the condition for entering the thermal runaway uninterrupted power supply mode is met, executing the thermal runaway uninterrupted power supply mode; and when the thermal runaway uninterrupted power supply mode is executed, continuously monitoring the state of the battery pack, and exiting the thermal runaway uninterrupted power supply mode when the preset exit condition is met.

[0052] Specifically, when judging whether the condition for entering the thermal runaway uninterrupted power supply mode is met, the battery management system or the vehicle controller usually monitors and analyzes the operating parameters and environmental parameters of the battery pack in real time. The judgment process can be based on a preset logic rule or algorithm, for example, by comparing the currently monitored parameters with the preset threshold, or by analyzing the parameter change trend to determine whether the condition for entering the mode is met. For example, the battery management system can continuously receive and process the state parameters from the battery cell and the environmental parameters in the box from the detection device, and trigger the judgment of entering the uninterrupted power supply mode according to the combination or single condition of these parameters.

[0053] After the conditions for entering the thermal runaway battery backup mode are met, the system will execute the thermal runaway battery backup mode. The execution process aims to maintain the basic operating ability of the vehicle and the cooling function of the battery pack to deal with the thermal runaway event. In specific implementation, the vehicle controller or the battery management system can send instructions to the relevant execution mechanism, for example, adjust the charging and discharging strategy of the battery pack, start or enhance the operation of the cooling system, etc. For example, after entering the mode, the system can limit the power output of the battery pack while requesting the highest level of cooling demand to maximize the suppression of the spread of thermal runaway.

[0054] During the execution of the thermal runaway battery backup mode, the system continuously monitors the battery pack state. This monitoring process is crucial to ensure the safe and effective operation of the backup mode. The battery management system will continuously collect various key data inside the battery pack and vehicle operating parameters, including but not limited to cell voltage, temperature, current, insulation state, etc., and perform real-time analysis on these data.

[0055] When the preset exit conditions are met, the system will exit the thermal runaway battery backup mode. The design of the exit conditions aims to ensure that the system can safely switch to other states, such as safe power-off, when the thermal runaway risk is effectively controlled or more serious failures occur. The exit process can be judged and executed by the battery management system or the vehicle controller according to the preset logic. For example, when the overall state of the battery pack tends to be stable, or a serious failure that cannot be solved by the backup mode occurs, the system will trigger the exit mechanism and take appropriate safety measures according to the specific situation.

[0056] Through the above technical solutions, the present application further introduces a thermal runaway battery backup control method based on the monitoring of the battery fire extinguishing system and the spraying of fire suppressant in the event of thermal runaway risk. This method avoids forced power-off at the initial or controllable stage of thermal runaway by conditionally entering, executing and exiting the backup mode, thereby effectively preventing the risk of rear-end collision caused by power-off and vehicle stalling. At the same time, since high-voltage power supply is maintained, the cooling system of the vehicle can continue to work and provide uninterrupted cooling for the battery pack, thereby shortening the duration of the high-temperature unsafe state and improving the thermal runaway suppression effect. In addition, when thermal runaway occurs in extreme weather or locations, the vehicle can still maintain basic operating ability to provide necessary energy support and escape opportunities for personnel, thereby improving the safety and reliability of the vehicle in the event of thermal runaway. Through the fine control strategy, the method maximizes the availability of the vehicle while ensuring safety, providing users with safer travel protection.

[0057] In one embodiment, the present application further proposes the conditions for entering the thermal runaway battery backup mode, such as Figure 4As shown, the conditions include: the battery management system determines that a thermal runaway early warning occurs and / or the environmental parameters monitored by the detection device reach the preset failure alarm threshold; and the fire extinguishing device sprays the fire suppressant.

[0058] Specifically, the battery management system is used to monitor the state parameters of each cell in the battery pack in real time, such as voltage, current, temperature, etc. When these parameters change abnormally and their change trends meet the early characteristics of thermal runaway, such as rapid temperature rise of a single cell, large temperature difference between cells, abnormal voltage fluctuation, etc., the battery management system will determine that a thermal runaway early warning occurs according to the preset algorithm model or threshold. This early warning mechanism can actively identify the risk of thermal runaway from the inside of the battery. In addition, the detection device is used to monitor the environmental parameters inside the battery pack box, such as smoke concentration, carbon monoxide concentration and temperature, etc. When any one or combination of these environmental parameters reaches the preset failure alarm threshold, the detection device will send an alarm signal. This monitoring method can passively and multi-dimensionally verify the thermal runaway event from the outside of the battery pack.

[0059] The above two conditions, i.e. the battery management system determines that a thermal runaway early warning occurs and / or the environmental parameters monitored by the detection device reach the preset failure alarm threshold, provide early and multiple confirmations of the thermal runaway event. On this basis, the fire extinguishing device sprays the fire suppressant, which means that the fire extinguishing device in the battery fire extinguishing system has actually started and sprayed the internally filled fire suppressant into the battery pack box after receiving the control instruction. The fire suppressant can be aerosol, water-based fire extinguishing agent or inert gas, etc. The action of the fire extinguishing device spraying the fire suppressant is a clear signal that the fire extinguishing system has intervened and started to perform the fire extinguishing task, and is also an important prerequisite for safety. When it is determined that a thermal runaway early warning occurs and / or the environmental parameters monitored by the detection device reach the preset failure alarm threshold, but the fire extinguishing bottle group is in the state of not spraying, it is normally handled according to the thermal runaway failure level, generally forced to disconnect the relay after 5-30S, and the vehicle is powered off.

[0060] By the above technical solution, the present application takes the environmental parameter alarm of the battery management system's thermal runaway pre-warning or detection equipment as the early identification basis of the thermal runaway event, and combines the confirmation that the fire extinguishing equipment has started the fire suppression agent, as the condition for entering the thermal runaway continuous power mode. This combined judgment mechanism avoids the misjudgment or omission that may be caused by single condition judgment, ensures that the thermal runaway continuous power mode is only activated when the thermal runaway event actually occurs and the fire extinguishing system has started to intervene, thereby ensuring the timeliness and accuracy of mode entry. In the thermal runaway continuous power mode, the vehicle can continue to supply power, avoiding the risk of vehicle stalling due to power failure, especially in high-speed working conditions, improving driving safety. At the same time, due to continuous power, the cooling equipment such as electric compressor can continue to work to provide continuous cooling for the battery cell, effectively suppress the spread of high temperature, prolong the effective cooling time of the battery pack, and reduce the harm degree of thermal runaway. In addition, in extreme environments, the continuous running capability of the vehicle also provides necessary energy support and escape opportunities for personnel.

[0061] In one embodiment, the present application further proposes to execute the thermal runaway continuous power mode, including: limiting the charge and discharge power of the battery pack, and requesting the highest level of battery cooling demand. The limited charge and discharge power is 1 / 5-1 / 4 of the rated charge and discharge power, and the requested highest level of cooling demand is the maximum compressor refrigeration capacity, the lowest water inlet temperature, and the maximum liquid cooling flow.

[0062] In the thermal runaway continuous power mode, limiting the charge and discharge power of the battery pack aims to reduce the heat generation rate inside the battery, thereby slowing down the spread of thermal runaway and giving more time to the cooling system. Specifically, this limitation can be achieved by the battery management system (BMS) sending instructions to the vehicle controller (VCU), which in turn controls the inverter or charging module to ensure that the actual charge and discharge current of the battery pack does not exceed the set upper limit.

[0063] Requesting the highest level of battery cooling demand is to maximize the removal of heat generated by the battery pack when a thermal runaway event occurs, effectively inhibiting the transfer of heat between battery cells and preventing further spread of thermal runaway. This usually involves the full intervention of the battery thermal management system (BTMS). In addition to requesting the maximum compressor refrigeration capacity, the lowest water inlet temperature, and the maximum liquid cooling flow, it can also be achieved by the following ways: for example, starting all available cooling circuits and cooling pumps to run at maximum power; preferentially allocating cooling resources to the battery pack, temporarily reducing or shutting down the cooling demand of other non-critical components; or if the system is equipped with auxiliary cooling devices (such as additional radiators or fans), activating them all to enhance the cooling capacity.

[0064] By the technical solution, after entering the thermal runaway continuous power supply mode, the battery pack charging and discharging power is limited, the internal heat generation and electrochemical reaction intensity of the battery in the thermal runaway state are reduced, the further deterioration or battery failure caused by overload is avoided, and meanwhile, the necessary power supply of the vehicle in an emergency is ensured, and the safety risk caused by sudden power failure of the vehicle is avoided. Meanwhile, by requesting the highest level of battery cooling demand, the heat dissipation efficiency of the battery pack can be maximized, and the heat generated by the thermal runaway cell can be quickly removed, so as to effectively inhibit the heat transfer to the surrounding healthy cells, delay or prevent the spread of thermal runaway. The synergistic effect of power limitation and intensified cooling enables the battery pack to continuously operate without power failure in the thermal runaway event, improves the safety and reliability of the system, provides valuable emergency disposal time for the driver and passengers, and avoids secondary accidents caused by power failure in critical working conditions such as high-speed driving.

[0065] In one embodiment, the application further proposes the conditions for exiting the thermal runaway continuous power supply mode as described above, which include at least one of the following: Figure 5 (1) any high-voltage component of the vehicle has an insulation fault; (2) the total voltage of the battery pack is abnormal; (3) the duration of the thermal runaway continuous power supply mode reaches a preset threshold; (4) the overall state of charge of the battery pack is lower than a preset value; (5) the battery pack has no current output response; (6) there is a fault that needs to be powered off, including at least one of thermal control fault, extreme under-voltage fault, and vehicle collision fault; (7) on the basis of limited charging and discharging power, a fault that needs to further limit the charging and discharging power occurs; (8) the actual voltage of the sampled offline cell that has not occurred thermal runaway abnormally decreases; (9) the actual voltage of the sampled offline cell that has not occurred thermal runaway is normal, and the environmental parameters monitored by the detection device detector reach a preset fault alarm threshold.

[0066] Specifically, when any high-voltage component of the vehicle has an insulation fault, the condition aims to identify the damage to the insulation integrity in the high-voltage system of the vehicle. The insulation fault can cause electric leakage, short circuit, and even electric shock risk. Its implementation can be to continuously measure the insulation resistance between the high-voltage system and the vehicle body chassis by the insulation monitoring unit (IMU) of the vehicle, and once the resistance is lower than a preset safety threshold, it is determined that there is an insulation fault; or, by integrating a special insulation sensor inside the key high-voltage components (such as motor, inverter, high-voltage wire harness, etc.), the insulation state is fed back in real time. ​

[0067] When the battery pack total voltage is abnormal, this condition is used to detect abnormal fluctuations or deviations in the overall voltage of the battery pack. Abnormalities in the battery pack total voltage usually indicate serious integrity problems within the battery pack, such as large-area cell failure, internal short circuit, or significant deviation in voltage acquisition by the battery management system (BMS). Its implementation can be through the battery management system (BMS) to continuously monitor the overall voltage of the battery pack and compare it with the preset normal working range, and if it exceeds the range, it is determined to be abnormal When the duration of the thermal runaway continuous power mode reaches the preset threshold, this condition serves as a time limit mechanism to prevent the system from running in an abnormal state for a long time. Long-term operation in the thermal runaway continuous power mode may mean that the potential problem has not been effectively solved, or may cause the accumulation of other secondary failures. Its implementation can be through the battery management system (BMS) or vehicle controller (VCU) to start a timer when entering the thermal runaway continuous power mode, and when the timer reaches the preset maximum duration (such as 30 minutes or 1 hour), the exit condition is triggered.

[0068] When the overall state of charge of the battery pack is below the preset value, this condition is used to ensure that the battery pack still has a certain energy reserve when exiting the thermal runaway continuous power mode. Too low state of charge may result in the battery pack being unable to provide sufficient power to support subsequent vehicle operation, or unable to effectively maintain the operation of the thermal management system. Its implementation can be through the battery management system (BMS) to estimate the overall state of charge (SOC) of the battery pack in real time, and when the SOC is below the preset minimum safe operating threshold (such as 5% or 10%), the condition is triggered.

[0069] When the battery pack has no current output response, this condition aims to identify the situation where the battery pack loses basic power supply capability. This usually indicates that there is a serious open circuit, short circuit or major failure in the power output path within the battery pack, causing the battery pack to be unable to provide current as instructed. Its implementation can be through the vehicle controller (VCU) or battery management system (BMS) to issue a current output instruction to the battery pack, while monitoring the actual current output of the battery pack. If the actual measured current remains zero or far below the instruction value for a long time after the instruction is issued, it is determined to have no current output response.

[0070] When there is a fault that requires power down, this condition covers a series of serious faults that must be immediately cut off power to prevent the fault from expanding or causing more serious consequences. These faults can include at least one of thermal control faults, limit under-voltage faults, vehicle collision faults. Among them, the implementation of thermal control faults can be that the thermal management system (TMS) reports cooling pump failure, radiator blockage, or temperature sensor serious error, etc., resulting in ineffective cooling; the implementation of limit under-voltage faults can be that the BMS detects that the voltage of a single or multiple cells drops to the absolute minimum threshold, indicating that the cell has suffered irreversible damage; the implementation of vehicle collision faults can be that the vehicle's collision sensor (such as an accelerometer, impact sensor) detects a collision event exceeding the preset severity.

[0071] When there is a fault that requires further restriction of charging and discharging power on the basis of limited charging and discharging power, this condition indicates that even if power limiting measures have been taken in the thermal runaway continuous power mode, the condition of the battery pack is still deteriorating and requires more stringent intervention. Its implementation can be that the BMS detects a new fault (for example, a new cell voltage deviation, other module temperature abnormally high) under the condition of limited power operation (for example, the charging and discharging power is limited to 1 / 5 of the rated power according to the above method), and according to the preset safety logic, the new fault requires lower power limitation (for example, to 1 / 10 of the rated power or completely prohibit charging and discharging).

[0072] When the actual voltage of the sampled offline cell abnormally decreases without thermal runaway, this condition aims to find those cells that cannot be monitored in real time due to communication interruption or other reasons, but actual problems have occurred. Such abnormal decrease can indicate potential fault development and needs to be handled in time.

[0073] When the actual voltage of the sampled offline cell is normal and the environmental parameters detected by the detection device probe reach the preset fault alarm threshold without thermal runaway, this condition is used to identify the case where the cell itself voltage appears normal, but the internal environment of the battery pack has appeared abnormal. This can be caused by external factors or local non-cell faults, but also constitutes a safety hazard. Its implementation can be that the BMS confirms that the actual voltage of the sampled offline cell is within the normal range, and at the same time, the environmental parameters (such as smoke concentration, carbon monoxide concentration, temperature) detected by the detection device set in the box reach or exceed the respective preset fault alarm threshold.

[0074] By the technical solution, the application provides a set of comprehensive and refined thermal runaway continuous power mode exit conditions. These conditions not only cover the electrical and thermal abnormalities of the battery pack itself, but also consider the safety state of the whole vehicle high-voltage system, the duration of mode operation, the energy reserve of the battery pack, and environmental monitoring data and other multiple dimensions. In view of this, when the battery pack or vehicle has a serious failure, the system can timely and accurately identify and respond, avoid further deterioration of the failure due to incomplete or inaccurate exit conditions, and improve the overall safety and reliability of the battery fire extinguishing system. The scheme ensures that in the thermal runaway continuous power mode, once any condition that may endanger the safety of the vehicle or passengers occurs, the system can take decisive action, effectively reduce the safety hazard, and ensure the controllability and safety of the vehicle in extreme conditions.

[0075] In one embodiment, the application further provides a method for determining abnormal total pressure of a battery pack, that is, when the total pressure of the battery pack satisfies: U v ≥(L-N)×U d , it is determined that the total pressure of the battery pack is abnormal, wherein U v is the total pressure of the battery pack; L is the total number of battery cells in the battery pack; N is the number of battery cells in the battery pack that have thermal runaway; and U d is the current dynamic voltage, which is obtained by table lookup according to the temperature of the battery cell corresponding to the minimum SOC of the normal battery cell.

[0076] Specifically, the technical solution provides a quantitative and operable judgment basis by establishing an accurate mathematical condition to determine whether the total pressure of the battery pack is abnormal. The battery management system (BMS) continuously monitors the actual total pressure U v of the battery pack and calculates the expected total pressure (L-N)×U d of the battery pack composed of healthy battery cells (which may include sampled-off battery cells). If the actual total pressure is greater than or equal to the theoretical expected total pressure, it is determined that the total pressure of the battery pack is abnormal. This comparison process can be performed in real time by a processor inside the battery management system (BMS) or a vehicle control unit (VCU).

[0077] The total pressure of the battery pack refers to the voltage value across the battery pack collected by the battery management system (BMS) in real time through a high-precision voltage sensor. This voltage value reflects the overall potential of the battery pack under the current working state and is the direct basis for judging the total pressure abnormality.

[0078] The total number of battery cells in the battery pack refers to a fixed parameter determined when the battery pack is designed, indicating the sum of all battery cells constituting the battery pack. L is a pre-set system configuration parameter, which is determined and stored in the memory of the battery management system (BMS) when the battery pack is assembled.

[0079] N is the number of cells in thermal runaway in the battery pack, which refers to the number of single cells inside the battery pack that have been confirmed or diagnosed as having a thermal runaway event. N is determined in real time by the battery management system (BMS) based on the cell state parameters it monitors. For example, when the temperature of a certain cell rises sharply and exceeds a preset threshold, the BMS will mark it as a thermal runaway cell and update the value of N. N can also be determined by analyzing the abnormal drop in cell voltage or significant changes in internal impedance.

[0080] U d is the current dynamic voltage, obtained by looking up the temperature of the cell corresponding to the minimum SOC in the normal cells, which is a dynamically changing reference voltage value that represents the expected voltage of a healthy cell under the current operating conditions. Its dynamic nature lies in its adjustment according to the state of charge (SOC) and temperature of the battery. Implementation method one, the battery management system (BMS) pre-stores a voltage-SOC-temperature three-dimensional lookup table. This table is established through a large number of experimental data, recording the open-circuit voltage or operating voltage of healthy cells under different temperatures and state of charge. The BMS will monitor the state of charge (SOC) of all normal cells in real time and identify the cell with the minimum SOC value. At the same time, the current temperature of the minimum SOC cell is obtained. Using the SOC value and temperature of the minimum SOC cell, the corresponding voltage value in the pre-stored lookup table is queried, which is U d .

[0081] Through the above technical solution, the present application provides an accurate, dynamic and reliable battery pack total voltage abnormality judgment standard. This standard compares the actual battery pack total voltage with the theoretical total voltage of the cells excluding the influence of the thermal runaway cells, effectively eliminating the interference of the thermal runaway cells on the total voltage judgment, and fully considering the dynamic voltage characteristics of healthy cells under different state of charge (SOC) and temperature. This dynamic adaptive judgment mechanism ensures that in the thermal runaway continuous power mode, the detection of battery pack total voltage abnormality is more accurate and timely. Therefore, when the battery pack total voltage is indeed abnormal, the system can quickly and reliably trigger the decision to exit the thermal runaway continuous power mode, thereby effectively reducing the potential safety risk and improving the overall safety and operational reliability of the battery system.

[0082] In one embodiment, the present application further proposes a method for determining whether the actual voltage is abnormally decreased or normal, comprising: calculating the theoretical voltage U1 of the cells that have not occurred thermal runaway but have sampling dropped: U1 = (L - N - M) x U d ; calculating the actual voltage U2 of the cells that have not occurred thermal runaway but have sampling dropped: U2 = U v - (N + M) x U d ; If U1=0, it is determined that the actual voltage is normal; If U1>0, U1 is compared with U2. When (U1-U2) / U2≥A and the condition lasts for a set time, it is determined that the actual voltage is abnormally decreased. Otherwise, it is determined that the actual voltage is normal. Wherein, L is the total number of cells in the battery pack; N is the number of cells in thermal runaway in the battery pack; M is the number of normal cells in the battery pack, which is determined by the battery management system (BMS) according to the cell state parameters monitored by it in real time; U d U is the current dynamic voltage; A is the set decrease threshold.

[0083] Specifically, the theoretical voltage U1 of the cells not in thermal runaway but with sampling offline is calculated by the formula U1=(L-N-M)×U d The theoretical voltage of the cells not in thermal runaway but with sampling offline is calculated, which aims to establish an expected voltage reference for these cells. This calculation method can comprehensively consider the overall composition of the battery pack, the known fault state and the dynamic characteristics of the cells under the current working condition, thereby providing a highly accurate theoretical reference value. The calculation can be directly performed by the battery management system (BMS) using the battery parameters and real-time monitoring data stored in it.

[0084] In the calculation of the actual voltage U2 of the cells not in thermal runaway but with sampling offline, since the sampling lines of these cells may have been offline, their voltage cannot be directly measured, and therefore it needs to be calculated indirectly. The present application uses the formula U2=U v -(N+M)×U d The actual voltage of the cells not in thermal runaway but with sampling offline is derived by subtracting the total voltage of the cells in thermal runaway and normal cells from the total voltage of the battery pack. This method can effectively obtain the actual operating voltage information of these cells, and the calculation can also be completed by the BMS.

[0085] In the judgment logic, if the theoretical voltage U1 is equal to 0, it is directly determined that the actual voltage is normal. This situation usually means that there are no cells not in thermal runaway but with sampling offline in the battery pack (i.e. L-N-M=0), so there is no need for further voltage comparison, and it is directly determined as normal state, simplifying the judgment process.

[0086] When the theoretical voltage U1 is greater than 0, then U1 needs to be compared with U2. The present application further provides that when the relative difference (U1-U2) / U2 is greater than or equal to a set drop threshold A, and this condition lasts for a preset time, it is determined that the actual voltage is abnormally dropped, otherwise it is determined that the actual voltage is normal. This double judgment mechanism based on relative difference and duration can effectively avoid false judgments caused by transient voltage fluctuations, measurement noise or system transient disturbances. The drop threshold A is a configurable parameter, which allows adjustment according to different battery types, application scenarios or safety levels, such as setting it to 30% to balance the sensitivity and false alarm rate of detection. The continuous setting time ensures the stability of the abnormal state and avoids overreaction to temporary abnormalities, such as setting it to 5s.

[0087] Through the above technical solutions, the present application provides an accurate and robust battery cell voltage state judgment method. By introducing the theoretical voltage U1 based on the number of cells, dynamic voltage and temperature-SOC lookup table, and combining the actual voltage U2 calculated from the total voltage of the battery pack, a reliable voltage evaluation reference is provided for the cell that is sampled offline but not thermal runaway. By introducing the double judgment mechanism of relative difference threshold A and continuous setting time, transient noise and fluctuations can be effectively filtered out, ensuring that only real and continuous voltage drops are identified, improving the accuracy and reliability of the judgment of the actual voltage of the cell that is not thermal runaway but is sampled offline in the thermal runaway continuous power mode. This accurate judgment avoids unnecessary mode exit or delayed exit caused by false judgment, so that when the battery is in thermal runaway warning, the vehicle can be maintained in continuous power operation more safely and for a longer time, providing the driver with more emergency handling time, reducing the risk of rear-end collisions and other safety risks caused by sudden power failure in high-speed working conditions, and ensuring that personnel can obtain continuous energy support in extreme environments, improving the safety of the battery system and the reliability of the vehicle.

[0088] In one embodiment, the present application provides an automobile comprising the above battery fire extinguishing system and configured to perform the above thermal runaway continuous power control method.

[0089] The battery fire extinguishing system refers to the complete safety mechanism integrated into the vehicle for detecting and responding to battery thermal runaway events. The battery fire extinguishing system can be a standalone hardware module physically integrated into the vehicle chassis and equipped with dedicated sensors and actuators connected to the battery pack and vehicle control unit. Alternatively, the system can be a distributed system with components (e.g., sensors, nozzles, fire extinguishing agent containers) strategically placed around the battery pack and connected through the vehicle's existing communication network (e.g., CAN bus) for control and data exchange. The core function of the battery fire extinguishing system is to provide immediate and localized fire extinguishing capability to contain or extinguish thermal runaway events, preventing the spread of fire and protecting the safety of the vehicle and its occupants.

[0090] The configuration to execute the thermal runaway continuous power control method refers to the programming and interconnection of the vehicle's control architecture (e.g., vehicle control unit, battery management system, powertrain control unit) to implement the logic and operations defined by the thermal runaway continuous power control method. This configuration can manifest as the vehicle main control unit (VCU) hosting the main logic of the thermal runaway continuous power control method, receiving inputs from the battery management system (BMS) and other sensors, and issuing instructions to various subsystems of the vehicle (e.g., powertrain, cooling system). Alternatively, the battery management system (BMS) can be enhanced to integrate the entire logic of the thermal runaway continuous power control method, directly managing power output and cooling requests, and communicating critical state information to the VCU. This configuration ensures that upon detection of a thermal runaway event, the vehicle can intelligently manage its power and cooling resources to maintain operational capability rather than complete shutdown.

[0091] With the above technical solutions, the vehicle integrates the battery fire extinguishing system and the thermal runaway continuous power control method, solving the problems of power outage, cooling interruption, and personnel risk exposure in extreme environments after thermal runaway. Specifically, the vehicle includes a battery fire extinguishing system that can monitor battery status and environmental parameters in real time and automatically activate fire extinguishing equipment to spray fire suppression agents into the box when the preset spraying conditions are met, effectively controlling the spread of fire. Meanwhile, the vehicle is configured to execute the thermal runaway continuous power control method, which can actively determine whether to enter the thermal runaway continuous power mode, limit the charging and discharging power of the battery pack to reduce safety risks, and request the highest level of cooling demand to maximize the cooling effect. In addition, the vehicle continuously monitors the battery pack status and safely exits the mode when the preset exit conditions are met. This integration and configuration ensure that the vehicle can maintain operational capability, maintain cooling function, and avoid personnel exposure to extreme environmental threats during thermal runaway events, thereby improving the safety, reliability, and comfort of the vehicle and its occupants.

[0092] The above examples are only used to illustrate the technical solutions of the present application, but not to limit the present application; although the present application has been described in detail with reference to the foregoing examples, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing examples can be modified, or some technical features can be replaced by equivalent ones; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application. The contents not described in detail in the specification belong to the prior art known by those skilled in the art.

Claims

1. A battery fire suppression system characterized by: The battery fire extinguishing system comprises a box, a fire extinguishing device, a battery management system and a battery pack composed of a plurality of battery cells arranged in the box, The fire extinguishing device is filled with fire extinguishing agent and is in communication with the inside of the box; The battery management system is used to monitor the state parameters of the battery cells; The box is further provided with a detection device for monitoring the environmental parameters in the box; The battery management system and / or the detector are used to determine whether to control the fire extinguishing device to start and spray the fire extinguishing agent into the box when the preset spraying condition is met based on the monitored parameters.

2. The battery fire suppression system of claim 1, wherein: The fire extinguishing device comprises a fire extinguishing bottle group and a fire extinguishing pipeline, the fire extinguishing bottle group is filled with fire extinguishing agent, and the fire extinguishing pipeline connects the fire extinguishing bottle group and a spray head arranged in the box.

3. The battery fire suppression system of claim 1, wherein, The preset spraying condition comprises: The battery management system determines that a thermal runaway warning occurs; or The environmental parameter monitored by the detector reaches a preset fault alarm threshold.

4. A battery thermal runaway uninterrupted power supply control method based on the battery fire extinguishing system of claim 1, characterized in that: determining whether the condition for entering the thermal runaway uninterrupted power supply mode is met; if the condition for entering the thermal runaway uninterrupted power supply mode is met, executing the thermal runaway uninterrupted power supply mode; continuously monitoring the state of the battery pack and exiting the thermal runaway uninterrupted power supply mode when the preset exit condition is met.

5. The battery thermal runaway without power failure control method according to claim 4, wherein, The condition for entering the thermal runaway uninterrupted power supply mode comprises: the battery management system determines that a thermal runaway warning occurs and / or the environmental parameter monitored by the detection device reaches a preset fault alarm threshold; and the fire extinguishing device sprays fire extinguishing agent.

6. The battery thermal runaway without power failure control method according to claim 4, wherein, The execution of the thermal runaway uninterrupted power supply mode comprises: limiting the charging and discharging power of the battery pack and requesting the highest level of battery cooling demand.

7. The battery thermal runaway without power cut control method according to claim 4, characterized in that, The preset exit condition comprises at least one of the following: (1) any high-voltage component of the vehicle has an insulation fault; (2) the total pressure of the battery pack is abnormal; (3) the duration of the thermal runaway uninterrupted power supply mode reaches a preset threshold; (4) the overall state of charge of the battery pack is lower than a preset value; (5) the battery pack has no current output response; (6) there is a fault that requires power down; (7) on the basis of the limited charging and discharging power, a fault that requires further limitation of the charging and discharging power occurs; (8) the actual voltage of a battery cell that has not experienced thermal runaway but has a sampling drop line abnormally decreases; (9) the actual voltage of a battery cell that has not experienced thermal runaway but has a sampling drop line is normal and the environmental parameter monitored by the detection device reaches a preset fault alarm threshold.

8. The battery thermal runaway without power cut-off control method of claim 7, wherein: When the total voltage of the battery pack satisfies: U v ≥(L-N)×U d , the total voltage of the battery pack is determined to be abnormal, wherein U v is the total voltage of the battery pack; L is the total number of battery cells in the battery pack; N is the number of battery cells in the battery pack that have thermal runaway; and U d is the current dynamic voltage.

9. The battery thermal runaway without power cut control method according to claim 7, characterized in that, Determining whether the actual voltage abnormally decreases or is normal comprises: Calculate the theoretical voltage U1 of the battery cell for which thermal runaway does not occur but sampling is offline: U1 = (L - N - M) x U d ; Calculate the actual voltage U2 of the cell for which thermal runaway did not occur but for which sampling was lost: U2 = U v - (N + M) x U d ; if U1=0, it is determined that the actual voltage is normal; if U1>0, U1 is compared with U2, when (U1-U2) / U2≥A and the duration is a set time, it is determined that the actual voltage abnormally decreases, otherwise it is determined that the actual voltage is normal. Wherein, L is the total number of battery cells in the battery pack; N is the number of battery cells in the battery pack that have thermal runaway; M is the number of normal battery cells in the battery pack; U d is the current dynamic voltage; A is the set drop threshold.

10. An automobile characterized by comprising: The battery fire extinguishing system comprises a box, a fire extinguishing device, a battery management system and a battery pack composed of a plurality of battery cells arranged in the box, The fire extinguishing device is filled with fire extinguishing agent and is in communication with the inside of the box; The battery management system is used to monitor the state parameters of the battery cells; The box is further provided with a detection device for monitoring the environmental parameters in the box; The battery management system and / or the detector are used to determine whether to control the fire extinguishing device to start and spray the fire extinguishing agent into the box when the preset spraying condition is met based on the monitored parameters.

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