Working safety detection control method for power battery

Abstract

The invention discloses a power battery working safety detection control method, which comprises the following steps: acquiring temperature, voltage and internal resistance change parameters in real time at a preset frequency through a temperature sensor, a voltage acquisition module and an internal resistance detection unit, comprehensively reflecting the working state of a battery, comprehensively calculating each parameter through a target safety value K, and accurately measuring the safety risk degree of the battery. Control actions such as limiting charging and discharging current, starting a cooling fan, cutting off a power supply loop, starting a liquid cooling system and triggering a fire extinguishing device are adopted in a graded mode according to the K value and related conditions, the control strength is gradually enhanced, potential safety hazards of different degrees can be handled in time and in a targeted mode, safety risks caused by abnormal temperature, voltage and internal resistance of a battery are reduced, and the service life of the battery is prolonged. Safe and stable operation of the power battery is ensured.

Description

Technical Field

[0001] This application relates to the technical field of power battery safety detection, and particularly to a method for detecting and controlling the working safety of a power battery. Background Art

[0002] With the rapid development of new energy vehicles, energy storage systems, and electric devices, as the core energy carrier, the safety and reliability of power batteries have become the focus of industry attention. Lithium-ion batteries are widely used due to their high energy density and long cycle life. However, their chemical system characteristics determine that there is a potential risk of fire or even explosion under extreme conditions such as overcharging, over-discharging, short-circuiting, mechanical abuse, or thermal runaway. In recent years, safety accidents caused by battery thermal runaway have occurred frequently, exposing the deficiencies of traditional safety monitoring technologies. Therefore, developing an efficient and accurate method for detecting and controlling the safety of power batteries has become a technical bottleneck that the industry urgently needs to break through.

[0003] In the prior art, the safety monitoring of power batteries mostly relies on the judgment of a single parameter threshold (such as temperature or voltage exceeding the limit), lacking a comprehensive evaluation of the coupling mechanism of multiple parameters. For example, only monitoring temperature may lead to missed judgments of voltage abnormalities or internal resistance mutations, while relying solely on voltage thresholds cannot effectively identify the hidden danger of temperature rise caused by internal micro-short circuits. In addition, traditional methods generally adopt fixed safety thresholds and do not consider the risk characteristic differences of batteries in different working states (such as charging, high-rate discharging). For example, side reactions during charging may cause more significant voltage fluctuations, while the internal resistance temperature rise effect is more prominent during high-rate discharging. However, existing methods are difficult to dynamically adjust parameter weights to adapt to these scenarios.

[0004] At the control strategy level, most solutions adopt a "one-size-fits-all" response mechanism. For example, directly cutting off the power supply circuit or only starting basic heat dissipation, there are problems of response lag or over-intervention. For example, when the battery is in the early abnormal stage (such as local temperature rise), if current limiting or enhanced heat dissipation measures are not taken in time, the golden window period for suppressing thermal runaway may be missed; once an emergency shutdown is triggered, it will cause the system to stop, affecting the user experience and equipment availability. At the same time, the existing sensor layout density is insufficient (such as single-point temperature measurement), making it difficult to capture the gradient changes in the battery surface temperature distribution, which may lead to missed detection of local hot spots and further exacerbate safety hazards.

[0005] Traditional methods rely on the independent judgment of a single parameter (such as temperature or voltage) and cannot quantify the combined effect of the temperature change rate (ΔT), voltage fluctuation (ΔV), and internal resistance abnormality (ΔR) on safety. For example, when dendritic growth occurs inside the battery, it may be manifested as a sudden increase in internal resistance but a lag in temperature rise, and single-parameter monitoring is prone to missed judgments.

[0006] Existing safety threshold models do not adjust parameter weights for different operating states such as charging and high-rate discharging. For example, during charging, the electrolyte decomposition reaction intensifies, and voltage fluctuations may become more sensitive risk indicators. While during high-rate discharging, the ohmic heating effect dominates, and the weight of the temperature change rate needs to be increased. Summary of the Invention

[0007] In an exemplary embodiment of the present application, a method for detecting and controlling the working safety of a power battery is provided to achieve multi-dimensional accurate detection and control of the working safety of the power battery.

[0008] The present application provides a method for detecting and controlling the working safety of a power battery, including the following steps:

[0009] By using a temperature sensor, a voltage acquisition module, and an internal resistance detection unit integrated in the power battery, the working state of the battery is monitored at a preset sampling frequency respectively, and the temperature change value ΔT (unit: °C / s), voltage change value ΔV (unit: V / s), and internal resistance change rate ΔR (unit: %) of the power battery are obtained in real time;

[0010] When the power battery is in an operating state, a target safety value K is determined, where

[0011] K = 0.5×ΔT + 0.3×(ΔV)^2 + 0.2×|ΔR|;

[0012] According to the magnitude relationship between the target safety value R and the safety threshold, corresponding levels of control actions are determined, where:

[0013] When K < 50, maintain the current operating state of the power battery;

[0014] When 50 ≤ K < 80, perform a first-level control action: limit the charge and discharge current to 70% of the rated value through the battery management system, and at the same time drive the cooling fan to start running;

[0015] When K ≥ 80 or ΔR ≥ 15%, perform a second-level control action: control the relay to cut off the power supply circuit of the power battery within 100 ms, and at the same time drive the drive pump of the liquid cooling system to start running;

[0016] When K ≥ 120 and ΔT ≥ 10 °C / s, perform a third-level control action: trigger the aerosol fire extinguishing device to spray fire extinguishing agent towards the power battery.

[0017] Further, the temperature sensor adopts a distributed fiber optic grating sensor array, and the temperature sensors are arranged in sequence at intervals of 5 cm along the surface of the power battery.

[0018] Further, it further includes: when the power battery is in a charging state, the target safety value K is: K = 0.5×ΔT + 0.35×(ΔV)^2 + 0.2×|ΔR|.

[0019] Further, it further includes: when the power battery is in a high-rate discharge state, the target safety value K is: K = 0.6×ΔT + 0.3×(ΔV)^2 + 0.2×|ΔR|.

[0020] Further, the primary control action further includes: when ΔT exceeds 5°C / s continuously for 3 seconds, increase the rotation speed of the cooling fan; otherwise, maintain the rotation speed of the cooling fan.

[0021] Further, when the discharge current of the power battery is greater than or equal to 3C and the duration for which the discharge current is greater than or equal to 3C exceeds 30s, and the surface temperature rise rate ΔT of the power battery is ≥2°C / s and the SOC value of the power battery is less than or equal to 30%, drive the power battery to be in a high-rate discharge state; where C is the 1-hour discharge rate corresponding to the rated capacity of the power battery.

[0022] The embodiments of the present application have the following beneficial effects: The working safety detection and control method for the power battery monitors in multiple dimensions in terms of improving the detection and control of working safety performance. Through the temperature sensor, voltage acquisition module, and internal resistance detection unit, the temperature, voltage, and internal resistance change parameters are obtained in real time at a preset frequency, comprehensively reflecting the working state of the battery. By calculating the target safety value K based on various parameters, the safety risk level of the battery is accurately measured. Control actions are taken at different levels according to the K value and related conditions, such as restricting the charge and discharge current, starting the cooling fan, cutting off the power supply circuit, starting the liquid cooling system, triggering the fire extinguishing device, etc., gradually increasing the control intensity, being able to timely and specifically handle safety hazards of different levels, reducing the safety risks caused by abnormal temperature, voltage, and internal resistance of the battery, and ensuring the safe and stable operation of the power battery. Description of the Drawings

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0024] Figure 1 The flowchart of a working safety detection and control method for a power battery provided by an embodiment of the present application is exemplarily shown. Detailed Embodiments

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of this application.

[0026] To further illustrate the technical solutions provided by the embodiments of this application, the following provides a detailed description with reference to the accompanying drawings and specific implementation manners. Although the embodiments of this application provide method operation steps as shown in the following embodiments or drawings, more or fewer operation steps may be included in the method based on routine or non-creative labor. In steps where there is no necessary causal relationship logically, the execution order of these steps is not limited to the execution order provided by the embodiments of this application.

[0027] Refer to Figure 1 As shown, this application provides a method for detecting and controlling the working safety of a power battery, including the following steps:

[0028] By using a temperature sensor, a voltage acquisition module, and an internal resistance detection unit integrated in the power battery, the working state of the battery is monitored at a preset sampling frequency respectively, and the temperature change value ΔT (unit: °C / s), voltage change value ΔV (unit: V / s), and internal resistance change rate ΔR (unit: %) of the power battery are obtained in real time.

[0029] Distributed fiber Bragg grating sensor arrays are used for temperature monitoring on the surface of the power battery module. The temperature sensor uses distributed fiber Bragg grating sensor arrays. The temperature sensors are arranged in sequence at intervals of 5 cm along the surface of the power battery, and a temperature monitoring point is set at intervals of 5 cm along the longitudinal axis of the battery case, forming a temperature sensing network covering more than 80% of the surface area of the power battery body.

[0030] The voltage acquisition module is connected to the positive and negative electrodes of each battery cell through a multi-channel isolation sampling circuit, and the internal resistance detection unit uses the AC injection method to realize dynamic impedance measurement.

[0031] The temperature data is continuously collected at a sampling frequency of 20 Hz, the voltage parameters are sampled at a high speed at a frequency of 1 kHz, and the internal resistance parameters are measured once every 5 seconds.

[0032] When the power battery is in an operating state, a target safety value K is determined, where

[0033] K = 0.5×ΔT + 0.3×(ΔV)^2 + 0.2×|ΔR|.

[0034] The K value linearly weights and integrates three key parameters: temperature change (ΔT), square of voltage change (ΔV2), and absolute value of internal resistance change rate (|ΔR|), and the weight distribution is 0.5:0.3:0.2.

[0035] The temperature change (weight 0.5) reflects the thermal runaway risk and is a core indicator of battery safety. An overly rapid temperature rise (e.g., ≥10°C / s) directly triggers the highest-level fire extinguishing action, demonstrating its dominant position. The temperature change has a significant impact on the safety of power batteries. Excessive temperature will accelerate battery aging and trigger serious safety problems such as thermal runaway. Assigning a weight coefficient of 0.5 to ΔT indicates that when evaluating the battery safety risk, the temperature factor is emphasized, making it account for a relatively large proportion in the calculation of the target safety value K, and it can more promptly reflect the threat of temperature anomalies to battery safety, facilitating the rapid adoption of countermeasures.

[0036] The square of the voltage change (weight 0.3) monitors electrochemical anomalies. The square operation amplifies the mutation signal (such as overcharge / overdischarge), while eliminating the directional influence. The weight coefficient of 0.3 in front of the voltage change (ΔV)² not only takes into account the important impact of voltage change on battery safety but also strengthens the impact of a larger voltage change on safety risk through the square operation. Small voltage fluctuations may have a limited impact on battery safety, but a large voltage change may indicate a fault inside the battery. Through this setting, voltage anomalies can be captured more sensitively.

[0037] The rate of change of internal resistance (weight 0.2) captures battery aging or internal short circuits. The absolute value processing focuses on the change amplitude rather than the direction. The weight coefficient of the rate of change of internal resistance |ΔR| is 0.2, indicating that although the change in internal resistance is also one of the factors affecting battery safety, its impact on safety risk is relatively small compared to temperature and voltage. This weight coefficient can reasonably balance the role of internal resistance change in the overall safety assessment and avoid overemphasizing or ignoring the contribution of internal resistance change to battery safety risk.

[0038] The temperature, voltage, and internal resistance of power batteries are key factors affecting their safety and performance. The temperature change value ΔT reflects the intensity of the internal chemical reaction of the battery and the heat dissipation situation. The voltage change value ΔV can reflect the charge and discharge state of the battery and the stability of the internal electrochemical performance. The rate of change of internal resistance ΔR reflects the change in the internal structure and materials of the battery.

[0039] By incorporating these three parameters into the calculation of the target safety value K, the working state of the battery is comprehensively reflected from multiple dimensions.

[0040] Assigning different weight coefficients (0.5, 0.3, 0.2) to different parameters is set based on the differences in the impact degrees of these parameters on battery safety risk. Among them, temperature has a greater impact on battery safety, so a higher weight of 0.5 is assigned; the square term of voltage (ΔV)² can more sensitively capture the impact of voltage change on safety risk; the absolute value of the rate of change of internal resistance |ΔR| is taken and a weight of 0.2 is assigned to measure the risk brought by the change in internal resistance.

[0041] Determine the corresponding level of control actions according to the magnitude relationship between the target safety value R and the safety threshold, where:

[0042] When K < 50, maintain the current operating state of the power battery.

[0043] When 50 ≤ K < 80, perform the first-level control action: limit the charge and discharge current to 70% of the rated value through the battery management system, and at the same time drive the cooling fan to start running.

[0044] The target safety value K synthesizes the temperature change value ΔT, voltage change value ΔV, and internal resistance change rate ΔR of the battery. When K is in the range of 50 - 80, it indicates that the operating state of the battery has become abnormal, but the risk level is relatively controllable. At this time, limiting the charge and discharge current to 70% of the rated value can reduce the intensity of the internal chemical reaction of the battery and reduce heat generation.

[0045] Driving the cooling fan to start running can enhance the heat dissipation ability of the battery, timely remove excess heat, prevent the battery temperature from rising further, and thus maintain the battery operating in a relatively safe state.

[0046] The first-level control action also includes: when ΔT exceeds 5°C / s continuously for 3 seconds, increase the speed of the cooling fan; otherwise, maintain the speed of the cooling fan.

[0047] When the temperature change rate ΔT exceeds 5°C / s continuously for 3 seconds, it indicates that the internal heat generation of the battery is relatively fast. If not dealt with in time, it may lead to excessive battery temperature and cause serious safety problems such as thermal runaway. Increasing the speed of the cooling fan can further enhance the heat dissipation effect, timely reduce the battery temperature, prevent the temperature from rising continuously and causing damage to the battery, and maintain the normal operating state of the battery.

[0048] When K ≥ 80 or ΔR ≥ 15%, perform the second-level control action: control the relay to cut off the power supply circuit of the power battery within 100 ms, and at the same time drive the drive pump of the liquid cooling system to start running.

[0049] For example, the temperature change rate ΔT = 60°C / s, voltage change rate ΔV = 15V / s, and internal resistance change rate ΔR = 10%.

[0050] According to = 0.5×ΔT + 0.3×(ΔV)^2 + 0.2×∣ΔR∣, K = 97.52 ≥ 80, which meets the condition, and perform the second-level control action (cut off the power supply circuit and start the liquid cooling system).

[0051] The target safety value K comprehensively reflects the changes in the temperature, voltage, and internal resistance of the battery. When K≥80, it indicates that the overall safety risk of the battery is already relatively high, and there may be interactions among multiple parameter abnormalities, posing a greater threat to battery safety. And ΔR≥15% means that the rate of change of the safety risk is relatively fast, and the battery state is deteriorating rapidly.

[0052] In these two cases, relying solely on primary control actions (such as limiting the charge and discharge current and starting the cooling fan) is no longer sufficient to address the current safety risks, and more powerful measures must be taken.

[0053] Cutting off the power supply circuit can immediately terminate the charge and discharge process of the battery, prevent the parameters such as temperature, voltage, and internal resistance of the battery from further deteriorating due to continuous abnormal charge and discharge, and prevent excessive accumulation of energy. At the same time, start the drive pump of the liquid cooling system, and use the stronger heat dissipation ability of the liquid cooling system to effectively reduce the battery temperature in a timely manner to alleviate the current relatively high safety risk.

[0054] When K≥120 and ΔT≥10℃ / s, execute the third-level control action: trigger the aerosol fire extinguishing device to spray the fire extinguishing agent on the power battery.

[0055] When K≥120, it indicates that the overall safety risk of the battery has reached an extremely high level, and the chemical reactions, voltage, and internal resistance conditions inside the battery are all in a severely abnormal state. At the same time, ΔT≥10℃ / s means that the battery temperature is rising at an extremely fast rate, the heat generation inside the battery is extremely fast and the heat dissipation is seriously insufficient, and the possibility of thermal runaway is extremely high, and a fire may be triggered at any time. At this time, relying solely on cutting off the power supply circuit and starting the liquid cooling system can no longer effectively prevent the occurrence of a fire caused by battery thermal runaway. Triggering the aerosol fire extinguishing device can quickly spray the fire extinguishing agent at the initial stage of the fire, inhibit the development of the fire, isolate oxygen, reduce the temperature, prevent the fire from spreading further, and prevent greater harm caused by the fire caused by thermal runaway.

[0056] Specifically, the judgment condition for executing the second-level control action is K≥80 or ΔR≥15%. The purpose is to intervene even when a single parameter is abnormal (such as temperature abnormality or voltage mutation) to prevent the risk from escalating. For example, a sudden increase in temperature may indicate local overheating (even if the voltage does not mutate), and a drastic voltage fluctuation may reflect electrochemical imbalance (even if the temperature does not exceed the standard).

[0057] The judgment condition for executing the third-level control action is K≥120 and ΔT≥10℃ / s. This third-level control action is an irreversible operation, involving system shutdown or hardware damage. It is necessary to strictly verify multiple parameter abnormalities through the "and" logic to avoid economic losses or deterioration of the user experience caused by mis-triggering. Only temperature abnormality may be caused by external heat source interference (such as high ambient temperature), or only voltage abnormality may be caused by load mutation (such as rapid acceleration of the motor). Abnormalities of both parameters at the same time probably indicate a battery body failure.

[0058] Furthermore, during the thermal runaway process of the power battery, there is a time-domain coupling relationship between ΔT and ΔV2 (the temperature rise rate is positively correlated with the voltage change rate). The "AND" logic can verify this physical correlation and exclude the influence of the failure of a single parameter sensor.

[0059] When the power battery is in the charging state, the target safety value K is: K = 0.5×ΔT + 0.35×(ΔV)^2 + 0.2×|ΔR|.

[0060] During charging, abnormal voltages (such as overcharging and sudden increase in monomer voltage) are the key inducements for triggering thermal runaway. Increasing the weight of ΔV (from 0.35 to 0.3) means that the contribution of voltage change is amplified in the K value. This makes it easier for the K value to reach the trigger threshold when the voltage rises rapidly, thus giving an early warning of the overcharging risk.

[0061] For example, if ΔV increases significantly within a short period, even if the temperature and internal resistance change slightly, the adjusted formula can trigger current limiting or power-off measures faster, avoiding internal short circuit or lithium plating caused by overvoltage in the battery.

[0062] During charging, the battery is in an energy input state with higher electrochemical activity, and voltage changes may reflect potential faults (such as SEI film decomposition and cathode material phase change) earlier than temperature or internal resistance. By increasing the coefficient of ΔV, the system can more sensitively capture voltage fluctuations caused by charger abnormalities, monomer imbalance, etc., and preferentially identify early risks through voltage signals rather than relying on temperature rise or internal resistance changes with stronger hysteresis.

[0063] During discharging, the voltage of the battery usually drops gently and controllably, while during charging (especially fast charging), the sudden rise in voltage may be directly related to irreversible chemical side reactions. After adjusting the coefficient, the calculation logic of the K value better fits the physical characteristics of the charging scenario, differentially allocating the monitoring priorities of each parameter - giving a higher decision-making weight to voltage changes during charging to ensure the pertinence and accuracy of the safety criterion.

[0064] When the power battery is in a high-rate discharging state, the target safety value K is: K = 0.6×ΔT + 0.3×(ΔV)^2 + 0.2×|ΔR|.

[0065] During high-rate discharging, the Joule heat and electrochemical reaction heat of the battery internal resistance increase significantly, and the temperature rise rate is much higher than that in normal conditions. Adjusting the ΔT coefficient to 0.6 directly increases the weight of temperature change in the K value, enabling the system to more sensitively capture the temperature rise signal caused by local overheating or abnormal heat dissipation, thus giving an early warning of the thermal runaway risk.

[0066] Temperature variations (such as the temperature difference ΔT between monomers) are usually an indirect manifestation of internal battery faults (such as internal short circuits, lithium plating, and SEI film decomposition). During high-rate discharges, these faults may deteriorate more rapidly due to the impact of high currents.

[0067] By increasing the coefficient of ΔT, the system can trigger a protection mechanism (such as power reduction or shutdown) before the abnormal temperature accumulates to a critical point, thus avoiding missing the optimal protection opportunity due to temperature hysteresis.

[0068] The electrochemical processes and failure mechanisms inside the battery during charging and discharging are different, and risk adaptation needs to be achieved through dynamic adjustment of the coefficient.

[0069] During charging: Electrochemical potential energy is input, and the risks are concentrated on voltage overload (overcharging) and side reactions of materials. It is necessary to monitor ΔV preferentially.

[0070] During high-rate discharge: Energy is released rapidly, and the risks are concentrated on thermal runaway and mechanical stress. It is necessary to monitor ΔT preferentially.

[0071] When the discharge current of the power battery is greater than or equal to 3C, the duration of the discharge current greater than or equal to 3C exceeds 30s, the surface temperature rise rate ΔT of the power battery is ≥2°C / s, and the SOC value of the power battery is less than or equal to 30%, it is determined that the power battery is in a high-rate discharge state. Here, C is the 1-hour discharge rate corresponding to the rated capacity of the power battery.

[0072] When multiple above conditions are met, heat will be generated rapidly inside the battery, and the surface temperature rise rate ΔT≥2°C / s intuitively reflects an increasing risk of thermal runaway. By judging these conditions, it is possible to promptly detect that the battery is in a dangerous state that may trigger thermal runaway, and take measures in advance, such as adjusting the discharge strategy and strengthening heat dissipation, to prevent serious safety accidents such as fires caused by thermal runaway.

[0073] High-rate discharge for a long time will cause irreversible damage to the battery and shorten its service life. Considering the condition that the SOC value is less than or equal to 30%, when high-rate discharge occurs at a low battery charge, this loss will be even more serious. By judging these conditions, the battery management system can limit high-rate discharge before the battery safety is threatened, protect the internal structure and active substances of the battery, and extend the overall service life of the battery.

[0074] If these condition judgments are not made and the battery is allowed to continuously discharge at a high rate in a dangerous state, it may lead to battery failure, affecting the normal operation of the entire battery system, and even triggering a chain reaction, affecting the safety of other devices connected to the battery. Judging these conditions and taking corresponding control measures, such as limiting the current and starting the heat dissipation device, can ensure the safe and stable operation of the entire system and reduce the probability of safety accidents.

[0075] The working safety detection and control method for the power battery conducts multi-dimensional monitoring in improving the detection and control of working safety performance. Through the temperature sensor, voltage acquisition module and internal resistance detection unit, the change parameters of temperature, voltage and internal resistance are obtained in real time at a preset frequency to comprehensively reflect the working state of the battery. By comprehensively calculating various parameters through the target safety value K, the safety risk degree of the battery is accurately measured. According to the K value and related conditions, control actions are taken at different levels, such as restricting the charge and discharge current, starting the cooling fan, cutting off the power supply circuit, starting the liquid cooling system, triggering the fire extinguishing device, etc. The control intensity is gradually enhanced, and different degrees of potential safety hazards can be timely and specifically addressed, reducing the safety risks caused by abnormal temperature, voltage and internal resistance of the battery, and ensuring the safe and stable operation of the power battery.

[0076] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0077] The present application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, and the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a device for implementing the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0078] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device, and the instruction device implements the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0079] These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus, such that a series of operational steps are performed on the computer or other programmable apparatus to produce a computer-implemented process, thereby providing instructions for implementing the functions specified in one process or a plurality of processes and / or boxes Figure 1 one process or a plurality of processes and / or boxes Figure 1 steps for implementing the functions specified in one box or a plurality of boxes.

[0080] Obviously, those skilled in the art can make various changes and modifications to this application without departing from the scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalent technologies, this application is also intended to cover these changes and modifications.

Claims

1. A method for detecting and controlling the working safety of a power battery, characterized in that, It includes the following steps: Through a temperature sensor, a voltage acquisition module, and an internal resistance detection unit integrated in the power battery, monitor the battery operating state at a preset sampling frequency respectively, and obtain the temperature change value ΔT (unit: °C / s), voltage change value ΔV (unit: V / s), and internal resistance change rate ΔR (unit: %) of the power battery in real time; When the power battery is in an operating state, determine the target safety value K, where K = 0.5×ΔT + 0.3×(ΔV)^2 + 0.2×|ΔR|; Determine the corresponding level of control action according to the magnitude relationship between the target safety value R and the safety threshold, where: When K < 50, maintain the current operating state of the power battery; When 50 ≤ K < 80, execute the first-level control action: limit the charge and discharge current to 70% of the rated value through the battery management system, and at the same time drive the cooling fan to start running; When K ≥ 80 or ΔR ≥ 15%, execute the second-level control action: control the relay to cut off the power supply circuit of the power battery within 100 ms, and at the same time drive the drive pump of the liquid cooling system to start running; When K ≥ 120 and ΔT ≥ 10 °C / s, execute the third-level control action: trigger the aerosol fire extinguishing device to spray the fire extinguishing agent on the power battery.

2. The method according to claim 1, wherein The temperature sensor adopts a distributed fiber optic grating sensor array, and the temperature sensors are arranged in sequence at intervals of 5 cm along the surface of the power battery.

3. The method according to claim 2, wherein It also includes: When the power battery is in a charging state, the target safety value K is: K = 0.5×ΔT + 0.35×(ΔV)^2 + 0.2×|ΔR|.

4. The method according to claim 1, wherein It also includes: When the power battery is in a high-rate discharge state, the target safety value K is: K = 0.6×ΔT + 0.3×(ΔV)^2 + 0.2×|ΔR|.

5. The method according to claim 1, characterized in that, The first-level control action also includes: when ΔT exceeds 5 °C / s continuously for 3 seconds, increase the rotation speed of the cooling fan, otherwise, maintain the rotation speed of the cooling fan.

6. The method according to claim 1, wherein When the discharge current of the power battery is greater than or equal to 3C and the duration of the discharge current greater than or equal to 3C exceeds 30s, and the surface temperature rise rate ΔT of the power battery ≥ 2 °C / s, and the SOC value of the power battery is less than or equal to 30%, drive the power battery to be in a high-rate discharge state; Wherein, C is the 1-hour discharge rate corresponding to the rated capacity of the power battery.

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