Discharge management method and device of battery management system, computer device and storage medium

Abstract

The application discloses a discharge management method and device of a battery management system, computer equipment and a storage medium. The method comprises the following steps: acquiring a temperature of a cell surface and a current voltage; if the temperature is greater than a first temperature threshold, setting a discharge cutoff voltage as a first voltage value; if the temperature is less than the first temperature threshold, performing dynamic adjustment based on a polarization voltage correction value to obtain a discharge cutoff voltage with a smaller voltage, and the polarization voltage correction value represents a part of the battery capacity hidden due to the temperature of the electrochemical reaction activity of the battery; and performing discharge management based on the discharge cutoff voltage. The fine temperature threshold switching scheme of the application finely considers the internal state of the battery, and simultaneously considers capacity maximization and safety at low temperature. The discharge cutoff voltage is dynamically adjusted according to the external temperature and the battery state, the available capacity is improved through voltage down exploration, and sufficient protection margin is reserved at high temperature. The technical problem that the battery endurance and safety are difficult to simultaneously consider is solved.

Description

Technical Field

[0001] This application relates to the field of battery management technology, and in particular to discharge management methods, devices, computer equipment, and storage media of battery management systems. Background Technology

[0002] In existing battery management systems (BMS), a fixed discharge cutoff voltage (VCutoff) is usually set to ensure battery safety and cycle life. For example, in an environment with a normal temperature of 25℃-40℃, the discharge cutoff voltage of lithium iron phosphate cells is usually set between 2.5V and 2.8V.

[0003] With the expansion of battery applications, especially in high-latitude or extreme climate regions, batteries often need to operate in temperatures below 0°C. Existing battery management systems (BMS) typically employ a single, fixed discharge cutoff voltage. On one hand, when the ambient temperature is below 0°C, the electrochemical activity of the battery decreases, leading to severe polarization. If the cutoff voltage at room temperature is continued, the BMS will forcibly stop discharging before the battery's actual capacity is fully released, resulting in a significant reduction in usable capacity and severely impacting the device's range. On the other hand, lowering the cutoff voltage to avoid forced discharge, while releasing more capacity, can lead to over-discharge and dissolution of the negative electrode copper current collector if precise control is lacking, causing irreversible capacity loss and even safety risks. Existing simple first temperature threshold switching schemes struggle to simultaneously maximize capacity and ensure safety at low temperatures. In other words, existing technologies present a technical challenge in simultaneously achieving both battery range and safety when controlling the BMS based on the existing discharge cutoff voltage. Summary of the Invention

[0004] This application provides a discharge management method, apparatus, computer equipment, and storage medium for a battery management system, which can solve the technical problem in the prior art where it is difficult to simultaneously ensure battery range and safety when controlling and managing the battery management system based on the existing discharge cutoff voltage.

[0005] In a first aspect, embodiments of this application provide a discharge management method for a battery management system, comprising: In response to a discharge management command, the internal state parameters of the target battery are acquired, including the cell surface temperature of the internal cells, the current voltage of the battery, and the battery's external output current. If the surface temperature of the battery cell is greater than a preset first temperature threshold, the discharge cutoff voltage is set to a preset first voltage value. If the cell surface temperature is less than the first temperature threshold, the corresponding battery temperature internal resistance and temperature coefficient are determined based on the cell surface temperature; the product of the battery temperature internal resistance, the temperature coefficient, and the output current is calculated to obtain the polarization voltage correction value; the polarization voltage correction value is reduced based on the discharge cutoff voltage to obtain a discharge cutoff voltage of the second voltage value, wherein the polarization voltage correction value characterizes the portion of battery capacity whose electrochemical reaction activity is hidden due to temperature, and the second voltage value is less than the first voltage value; Discharge management is performed on the target battery based on the discharge cutoff voltage and the current voltage.

[0006] In some embodiments, if the cell surface temperature is less than the first temperature threshold, the corresponding battery temperature internal resistance and temperature coefficient are determined based on the cell surface temperature, including: If the cell surface temperature is less than the first temperature threshold, the corresponding battery temperature internal resistance is obtained by looking up the cell surface temperature in a preset temperature internal resistance mapping table using a lookup table method. Alternatively, the surface temperature of the battery cell can be calculated using a preset algorithm model to obtain the corresponding internal resistance of the battery at temperature. Based on the surface temperature of the battery cell, the corresponding temperature coefficient is determined.

[0007] In some embodiments, if the cell surface temperature is less than the first temperature threshold, the corresponding battery temperature internal resistance is obtained by looking up the cell surface temperature in a preset temperature internal resistance mapping table using a lookup table method, including: If the surface temperature of the battery cell is less than the first temperature threshold, then the battery cell surface temperature is used to look up the value in a preset temperature resistance mapping table. If no temperature value directly corresponding to the surface temperature of the battery cell is found, select two adjacent temperature values ​​adjacent to the surface temperature of the battery cell from the table, as well as the adjacent resistance values ​​corresponding to each of the two adjacent temperature values. Based on the linear relationship between the cell surface temperature and two adjacent temperature values, the corresponding internal resistance of the battery is obtained by linearly calculating the two adjacent resistance values ​​using linear interpolation.

[0008] In some embodiments, discharge management is performed on the target battery based on the discharge cutoff voltage and the current voltage, including: If the surface temperature of the battery cell, which was originally below the first temperature threshold, rises and exceeds the first temperature threshold, it is determined whether the surface temperature of the battery cell exceeds a preset second temperature threshold, where the second temperature threshold is greater than the first temperature threshold. If the voltage is not exceeded, the discharge cutoff voltage is dynamically adjusted based on the polarization voltage correction value to obtain a discharge cutoff voltage with a second voltage value, and discharge management is performed on the target battery based on the discharge cutoff voltage and the current voltage. If the voltage is exceeded, the discharge cutoff voltage is set to the first voltage value, and discharge management is performed on the target battery based on the discharge cutoff voltage and the current voltage.

[0009] In some embodiments, discharge management is performed on the target battery based on the discharge cutoff voltage and the current voltage, including: If the current voltage is greater than the discharge cutoff voltage, then control the target battery to discharge until the current voltage drops to be equal to the discharge cutoff voltage; If the current voltage is less than the discharge cutoff voltage, the discharge circuit to the target battery is cut off.

[0010] In some embodiments, if the current voltage is greater than the discharge cutoff voltage, then controlling the target battery to discharge until the current voltage drops to be equal to the discharge cutoff voltage includes: If a rebound increase in the current voltage is detected, it is determined whether the current voltage exceeds a preset recovery voltage, wherein the recovery voltage is greater than the discharge cutoff voltage; If the limit is not exceeded, the discharge circuit for the target battery is locked.

[0011] Secondly, embodiments of this application also provide a discharge management device for a battery management system, the device comprising: The acquisition unit is used to acquire the internal state parameters of the target battery in response to the discharge management command. The internal state parameters include the cell surface temperature of the internal cells, the current voltage of the battery, and the battery's output current to the outside. The discharge cutoff voltage update unit is used to set the discharge cutoff voltage to a preset first voltage value if the surface temperature of the battery cell is greater than a preset first temperature threshold. The discharge cutoff voltage update unit is further configured to: if the cell surface temperature is less than the first temperature threshold, determine the corresponding battery temperature internal resistance and temperature coefficient based on the cell surface temperature; calculate the product of the battery temperature internal resistance, the temperature coefficient, and the output current to obtain the polarization voltage correction value; reduce the polarization voltage correction value based on the discharge cutoff voltage to obtain a discharge cutoff voltage of a second voltage value, wherein the polarization voltage correction value characterizes the portion of battery capacity whose electrochemical reaction activity is hidden due to temperature, and the second voltage value is less than the first voltage value; A discharge management unit is used to perform discharge management on the target battery based on the discharge cutoff voltage and the current voltage.

[0012] Thirdly, embodiments of this application also provide a discharge management computer device for a battery management system, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the above-described method.

[0013] Fourthly, embodiments of this application also provide a computer-readable storage medium storing a computer program, the computer program including program instructions that, when executed by a processor, can implement the above-described method.

[0014] This application provides a discharge management method, apparatus, computer device, and storage medium for a battery management system. The method includes: responding to a discharge management command, acquiring internal state parameters of a target battery, including the cell surface temperature of the internal cells, the current voltage of the battery, and the battery's output current; if the cell surface temperature is greater than a preset first temperature threshold, setting the discharge cutoff voltage to a preset first voltage value; if the cell surface temperature is less than the first temperature threshold, determining the corresponding battery temperature internal resistance and temperature coefficient based on the cell surface temperature; calculating the product of the battery temperature internal resistance, the temperature coefficient, and the output current to obtain a polarization voltage correction value; reducing the polarization voltage correction value based on the discharge cutoff voltage to obtain a second voltage value discharge cutoff voltage, where the polarization voltage correction value represents the portion of battery capacity whose electrochemical reaction activity is hidden due to temperature, and the second voltage value is less than the first voltage value; and performing discharge management on the target battery based on the discharge cutoff voltage and the current voltage. In this application, through a refined temperature threshold switching scheme and careful consideration of the battery's internal state, both capacity maximization and safety are achieved simultaneously at low temperatures. Addressing the significant battery capacity waste in low-temperature environments, this technology dynamically adjusts the discharge cutoff voltage based on ambient temperature and battery status. At low temperatures, it significantly increases usable capacity through a safe voltage reduction, while maintaining sufficient protection margin at high temperatures. This solves the technical problem in existing technologies where controlling the battery management system based on the current discharge cutoff voltage makes it difficult to simultaneously achieve both battery range and safety. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 A schematic flowchart of the discharge management method of the battery management system provided in the embodiments of this application; Figure 2 A schematic block diagram of a discharge management device for a battery management system provided in an embodiment of this application; Figure 3 A schematic block diagram of a computer device provided in an embodiment of this application. Detailed Implementation

[0017] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0018] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0019] It should also be understood that the terminology used in this application specification is for the purpose of describing particular embodiments only and is not intended to limit the application. As used in this application specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0020] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0021] In existing battery management systems (BMS), a fixed discharge cutoff voltage (VCutoff) is usually set to ensure battery safety and cycle life. For example, in an environment with a normal temperature of 25℃-40℃, the discharge cutoff voltage of lithium iron phosphate cells is usually set between 2.5V and 2.8V.

[0022] With the expansion of battery applications, especially in high-latitude or extreme climate regions, batteries often need to operate in temperatures below 0°C. Existing battery management systems (BMS) typically employ a single, fixed discharge cutoff voltage. On one hand, when the ambient temperature is below 0°C, the electrochemical activity of the battery decreases, leading to severe polarization. If the cutoff voltage at room temperature is continued, the BMS will forcibly stop discharging before the battery's actual capacity is fully released, resulting in a significant reduction in usable capacity and severely impacting the device's range. On the other hand, lowering the cutoff voltage to avoid forced discharge, while releasing more capacity, can lead to over-discharge and dissolution of the negative electrode copper current collector if precise control is lacking, causing irreversible capacity loss and even safety risks. Existing simple first temperature threshold switching schemes struggle to simultaneously maximize capacity and ensure safety at low temperatures. In other words, existing technologies present a technical challenge in simultaneously achieving both battery range and safety when controlling the BMS based on the existing discharge cutoff voltage.

[0023] To address the aforementioned technical problems, this application proposes a discharge management method, apparatus, computer equipment, and storage medium for a battery management system.

[0024] This application provides a discharge management method, apparatus, computer equipment, and storage medium for a battery management system. Through a precise temperature threshold switching scheme and careful consideration of the battery's internal state, it achieves both maximum capacity and safety at low temperatures. Addressing the problem of significant battery capacity waste in low-temperature environments, it provides a control method that dynamically adjusts the discharge cutoff voltage based on external temperature and battery state. This aims to significantly increase usable capacity at low temperatures by safely lowering the voltage, while maintaining sufficient protection margin at high temperatures.

[0025] Figure 1 This is a schematic flowchart of the discharge management method of the battery management system provided in an embodiment of this application. Figure 1 As shown, the method includes the following steps S110-S140: S110. In response to the discharge management command, obtain the internal state parameters of the target battery, including the cell surface temperature of the internal cells, the current voltage of the battery, and the battery's external output current. In this embodiment, the target battery can be a lithium iron phosphate (LFP) battery or other types of lithium-ion batteries.

[0026] Discharge management commands can be automatically triggered by the Battery Management System (BMS) when it detects that the battery is in a discharged state, or they can be issued by external control devices (such as vehicle controllers, energy storage system controllers, etc.).

[0027] Specifically, the cell surface temperature is acquired in real time by a temperature sensor positioned on the cell surface. This temperature sensor can be a negative temperature coefficient (NTC) thermistor, platinum resistance temperature sensor, or thermocouple, etc. The temperature sensor can be positioned at the center of the large surface area of ​​the cell or near the terminals to obtain representative temperature measurements. The battery's current voltage is acquired in real time by a voltage sampling circuit, which includes a voltage divider resistor network and an analog-to-digital converter (ADC). The ADC converts the divided analog voltage signal into a digital signal for the BMS processor to read.

[0028] In practical applications, the BMS periodically collects the aforementioned internal state parameters according to a preset sampling period, such as 10ms to 100ms, and stores them in the BMS's cache or memory for subsequent steps to call.

[0029] S120. If the surface temperature of the battery cell is greater than a preset first temperature threshold, the discharge cutoff voltage is set to a preset first voltage value. In this embodiment, a preset first temperature threshold T1 is used to distinguish between the normal temperature operating range and the low temperature operating range. Its specific value can be set according to the electrochemical characteristics of the target battery. For lithium iron phosphate cells, the first temperature threshold is preferably 0°C. When the cell surface temperature T≥T1, it indicates that the battery is currently operating in the normal temperature range (including 0°C and above). At this time, the electrochemical reaction activity of the battery is sufficient, the polarization phenomenon is not obvious, and the system enters the standard protection mode (mode one).

[0030] As an example, in standard protection mode, the discharge cutoff voltage V_cutoff is set to a preset first voltage value V_high. For lithium iron phosphate cells, the preferred range for V_high is 2.5V to 2.8V, more preferably 2.8V. Within this voltage range, priority is given to ensuring the battery's cycle life and safety, avoiding over-discharge that could lead to dissolution of the negative electrode copper current collector or the growth of copper dendrites.

[0031] It should be noted that within the normal temperature range, the system executes a standard discharge strategy. When the battery terminal voltage drops to V_high, the BMS issues a stop discharge command and disconnects the discharge circuit.

[0032] S130. If the cell surface temperature is less than the first temperature threshold, then determine the corresponding battery temperature internal resistance and temperature coefficient based on the cell surface temperature; calculate the product of the battery temperature internal resistance, the temperature coefficient, and the output current to obtain the polarization voltage correction value; reduce the polarization voltage correction value based on the discharge cutoff voltage to obtain a discharge cutoff voltage of the second voltage value, wherein the polarization voltage correction value characterizes the portion of battery capacity whose electrochemical reaction activity is hidden due to temperature, and the second voltage value is less than the first voltage value; In this embodiment, when the cell surface temperature T < T1, it indicates that the battery is currently operating in a low-temperature range. At this time, the battery's electrochemical reactivity decreases, the electrolyte viscosity increases, and the diffusion rate of lithium ions in the electrode material slows down, leading to a significant increase in ohmic polarization and concentration polarization. This increased polarization effect results in a falsely high battery terminal voltage. That is, the actual state of charge of the battery no longer corresponds to the terminal voltage at room temperature; the terminal voltage reaches the room-temperature cutoff voltage prematurely, while a considerable amount of remaining capacity inside the battery remains unreleased. The polarization voltage correction value in this application characterizes the portion of battery capacity hidden due to temperature-related electrochemical reactivity.

[0033] To release the capacity hidden due to polarization effects, the system enters a low-temperature capacity compensation mode (Mode 2). In Mode 2, the system dynamically adjusts the discharge cutoff voltage based on the polarization voltage correction value ΔV, lowering the discharge cutoff voltage from the first voltage value V_high to the second voltage value V_low.

[0034] If the cell surface temperature is less than the first temperature threshold, the corresponding battery temperature internal resistance and temperature coefficient are determined based on the cell surface temperature. Cell surface temperature refers to the temperature value measured on the surface of the cell casing using a temperature sensor such as an NTC thermistor or thermocouple. This is the most direct and commonly obtained battery temperature parameter in the BMS (Battery Management System). Cell surface temperature is currently the most feasible measurement method for large-scale commercial applications because directly embedding sensors inside the cell would damage its structure and pose safety hazards.

[0035] Battery internal resistance is not an independent physical quantity, but rather refers to the characteristic of battery internal resistance changing dynamically with temperature. In battery management systems, it typically refers specifically to the battery's DC internal resistance at the current temperature. Internal resistance is not a fixed value, but a dynamic parameter strongly affected by temperature.

[0036] Temperature is one of the most critical factors affecting internal resistance. For example, internal resistance increases sharply at low temperatures. Lowering the temperature slows down the diffusion rate of lithium ions in the electrolyte and the electrode reaction rate, leading to a significant increase in polarization resistance. Some studies have shown that internal resistance increases by approximately 15% to 25% for every 10°C decrease in temperature. At low temperatures (<10°C) or low discharge rates, concentration polarization resistance often dominates. Internal resistance decreases at high temperatures. As temperature increases, electrolyte viscosity decreases, ion diffusion and reaction rates accelerate, and therefore internal resistance decreases accordingly.

[0037] The internal resistance of a battery mainly consists of two parts: ohmic resistance and polarization resistance. Ohmic resistance is the resistance generated by electrode materials, electrolyte, separator, and connecting components, and follows Ohm's law. Polarization resistance is caused by the resistance during the electrochemical reaction process, and can be further subdivided into electrochemical polarization resistance caused by the slow electrochemical reaction rate at the electrode surface, and concentration polarization resistance caused by the slow diffusion rate of lithium ions in the electrolyte. The total internal resistance of a battery includes both ohmic resistance and polarization resistance.

[0038] In a Battery Management System (BMS), the battery's internal resistance at different temperatures can be obtained and used in two ways: 1. Table lookup method: The internal resistance values ​​of the battery at different temperatures are experimentally calibrated and compiled into a table. The BMS then collects the temperature in real time and obtains the current internal resistance value by looking up the table. 2. Online estimation method: The internal resistance is calculated in real time.

[0039] The temperature coefficient is an engineering empirical amplification factor. Its necessity lies in the fact that if voltage is corrected solely by multiplying the internal resistance by the current, the calculated voltage drop at the end of a low-temperature, high-current discharge will always be less than the actual voltage drop. This is because the battery's internal resistance is typically measured under short pulses, such as a 10-second HPPC test. However, actual discharge can last for several minutes or even hours. During prolonged discharge, the diffusion of lithium ions inside the negative electrode slows down significantly, and this additional accumulated voltage drop is not included in the battery's internal resistance measured under short pulses. The temperature coefficient effectively compensates for this gap by converting the long-term diffusion resistance into a multiple of the internal resistance.

[0040] If the cell surface temperature in step S130 is less than the first temperature threshold, the step of determining the corresponding battery temperature internal resistance and temperature coefficient based on the cell surface temperature includes steps A1-A3: A1. If the surface temperature of the battery cell is less than the first temperature threshold, the corresponding battery temperature internal resistance is obtained by looking up the battery cell surface temperature in a preset temperature internal resistance mapping table using a lookup table method. The table in the look-up table method is preset based on test data of hybrid pulse power characterization. A cell is placed in a constant temperature chamber, and after being stabilized at a specific temperature, it is discharged at a fixed rate for 10 seconds, and the instantaneous voltage drop value ΔU is recorded. The instantaneous voltage drop value ΔU herein refers to the voltage difference at the moment of current loading, for example, at the 1st second, which excludes the subsequent slow diffusion voltage drop to ensure that the measured ohmic internal resistance and instantaneous charge transfer impedance are obtained.

[0041] The reason why the corresponding battery internal resistance at temperature can be obtained by the look-up table method is that physically, internal resistance is inherently a function of temperature, and in engineering, surface temperature is the only available substitute for internal temperature, and this relationship is solidified into a table in advance through experimental calibration.

[0042] In some embodiments, A1 includes step B1 to step B3: B1: If the surface temperature of the cell is lower than the first temperature threshold, querying a preset temperature-internal resistance mapping table based on the surface temperature of the cell by the look-up table method; When querying the preset temperature-internal resistance mapping table based on the surface temperature of the cell by the look-up table method, if a node in the table is exactly hit, for example, a directly corresponding temperature value is obtained through querying, the resistance value of that node is directly returned, and steps B2 and B3 are skipped.

[0043] Through experiments, the internal resistance values or internal resistance percentages of the cell at a series of specific temperature points are measured and recorded in advance to form a temperature-internal resistance correspondence table. After the BMS acquires the current cell surface temperature T, it directly queries this table. If T exactly falls on a certain temperature point, the corresponding internal resistance value of that point is taken; if T falls between two temperature points, the corresponding internal resistance is calculated by linear interpolation.

[0044] The actual temperature is an analog quantity that changes continuously, and it is almost impossible to be exactly equal to an integer point in the calibration table. Actively capturing the upper and lower adjacent temperature values prevents the program from reporting an error or crashing due to failure to find data, and ensures the smoothness of control.

[0045] B2: If no temperature value directly corresponding to the surface temperature of the cell can be queried, selecting two adjacent temperature values adjacent to the surface temperature of the cell and respective adjacent resistance values corresponding to the two adjacent temperature values from the table; When querying in the preset temperature-internal resistance mapping table, if no temperature value directly corresponding to the surface temperature of the cell is directly queried, two adjacent temperature values adjacent to the surface temperature of the cell are selected from the table, which are denoted as T1 and T2. Let the surface temperature of the cell be T, and the two adjacent temperature nodes found through table look-up are T1 and T2 with T1<T<T2, and their corresponding internal resistance values are R1 and R2.

[0046] The standard calculation formula for linear interpolation is: R=R1+(R2-R1) / (T2-T1)×(T-T1) B3, based on the linear relationship between the cell surface temperature and two adjacent temperature values, linearly calculating two adjacent resistance values by a linear interpolation method to obtain the corresponding internal resistance of the battery at the temperature.

[0047] A2, or calculating the cell surface temperature by a preset algorithm model to obtain the corresponding internal resistance of the battery; The theoretical model of the preset algorithm model is the Arrhenius equation. For more precise control, especially when it is necessary to predict the behavior at extremely low temperatures, a model based on physicochemical principles is adopted.

[0048] The calculation principle of the cell surface temperature by the preset algorithm model is that the relationship between battery internal resistance, especially charge transfer resistance, and temperature closely follows the Arrhenius equation. This equation describes the exponential relationship between the chemical reaction rate and temperature, and the polarization reaction of a battery is exactly an electrochemical reaction.

[0049] The BMS substitutes the measured temperature T into the formula to calculate the current internal resistance.

[0050] In some embodiments, a more flexible data fitting method is adopted to improve accuracy. Instead of being limited to a certain physical formula, a mathematical function that can well describe the change of internal resistance over the entire temperature range, such as a polynomial or a piecewise function, is fitted through a large amount of experimental data.

[0051] As an example, for polynomial fitting, a high-order curve is used to pass through all experimental data points to obtain a polynomial equation. The BMS substitutes the temperature T into the equation for solving.

[0052] As an example, for a piecewise function, the temperature range is divided into several intervals, for example T>T1, T2<T<T1, T<T2, and different functions or coefficients are used to calculate the internal resistance in each interval. For example, some patents mention that when the temperature is lower than -15°C and between -15°C and 0°C, different correction coefficients are adopted.

[0053] A3, determining the corresponding temperature coefficient based on the cell surface temperature.

[0054] The temperature coefficient varies with the cell and temperature.

[0055] The temperature coefficient changes exponentially with temperature, and the internal resistance strictly follows the Arrhenius equation. For example, for every 10°C drop in temperature, the internal resistance increases by approximately 15% to 30%. At -20°C, the internal resistance can reach 3 to 5 times that at 25°C. The corresponding temperature coefficient is determined based on the cell surface temperature.

[0056] In some embodiments, the temperature coefficient also varies with the cell type, with high-energy-density cells exhibiting a much higher low-temperature internal resistance coefficient than power cells. Meanwhile, cylindrical cells have better heat dissipation due to their tab structure, and their internal resistance temperature coefficient is generally more stable than that of pouch cells.

[0057] The polarization voltage correction value is obtained by calculating the product of the battery temperature internal resistance, the temperature coefficient, and the output current. In a practical BMS, a basic internal resistance value is quickly obtained using a lookup table. Then, based on the current temperature and SOC, a temperature correction factor is looked up from another table. Finally, the basic internal resistance value is multiplied by the correction factor, and fine-tuned by considering the battery aging status, resulting in the final battery temperature internal resistance R(T) and temperature coefficient K value used for calculation. This multi-level, multi-model strategy ensures that the BMS can accurately and reliably estimate and control the battery state over a wide temperature range, from room temperature to extreme cold.

[0058] The polarization voltage correction value is obtained by calculating the product of the battery temperature internal resistance R(T), temperature coefficient K, and output current.

[0059] By reducing the polarization voltage correction value based on the discharge cutoff voltage, a second discharge cutoff voltage is obtained.

[0060] As an example, when the cell surface temperature is determined to be below the first temperature threshold of 0°C, the system enters a low-temperature capacity compensation mode. In this mode, the system does not simply reduce the voltage, but dynamically adjusts it based on the polarization voltage correction value ΔV at low temperatures to obtain a second discharge cutoff voltage value. For example, the discharge cutoff voltage is lowered to between 2.0V and 2.2V. Previously, the discharge cutoff voltage ranged from 2.5V to 2.8V.

[0061] S140. Based on the discharge cutoff voltage and the current voltage, perform discharge management on the target battery.

[0062] For specific battery cells, the BMS proactively performs discharge management based on their current real-time status, especially temperature, voltage, and aging level. This includes a series of dynamic current limiting, cut-off protection, and power regulation strategies to ensure safety and maximize available energy.

[0063] Discharge management is not simply about connecting the load and discharging the battery. It must include a rest and recovery period. If a high-current discharge causes the polarization voltage to be artificially high or low, the management strategy will pause the high-current output, wait for the internal chemical potential of the cell to reach equilibrium, and then reassess the open-circuit voltage to decide whether to continue discharging.

[0064] S140 includes S1401-S1403: S1401. If the surface temperature of the battery cell, which was originally lower than the first temperature threshold, rises and exceeds the first temperature threshold, it is determined whether the surface temperature of the battery cell exceeds a preset second temperature threshold, wherein the second temperature threshold is greater than the first temperature threshold. In some embodiments, a safety closed-loop and hysteresis control mechanism is provided. To avoid frequent jittering and switching near a critical first temperature threshold, such as 0°C, this application introduces hysteresis control. A second temperature threshold is provided, which is greater than the first temperature threshold.

[0065] Cells that were initially below the first temperature threshold will begin real-time monitoring as the temperature rises. When the surface temperature rises above the first temperature threshold, the monitoring will continue to check whether the surface temperature exceeds the second temperature threshold. Only when the second temperature threshold is exceeded will the mode switch be performed, that is, the switch from the low temperature capacity compensation mode to the high-precision protection mode in the normal temperature range will be executed to prevent the relay or load controller from malfunctioning.

[0066] S1402. If the voltage is not exceeded, the discharge cutoff voltage is dynamically adjusted based on the polarization voltage correction value to obtain a discharge cutoff voltage with a second voltage value, and discharge management is performed on the target battery based on the discharge cutoff voltage and the current voltage. S1403. If the voltage exceeds the limit, the discharge cutoff voltage is set to the first voltage value, and discharge management is performed on the target battery based on the discharge cutoff voltage and the current voltage.

[0067] This application transforms single-point critical judgment into dual-boundary-window judgment, artificially creating a dead zone to eliminate critical oscillations using state memory. The reason is that single-point control is prone to jitter. If the system's set temperature exceeds a first temperature threshold, it switches to a high-precision protection mode within the normal temperature range; if the temperature is below the first temperature threshold, it switches to a low-temperature capacity compensation mode. However, the actual cell surface temperature fluctuates around the first temperature threshold, such as between -0.5℃ and +0.5℃, due to coolant fluctuations, thermal inertia, or sensor noise. In this situation, the system will switch between the high-precision protection mode and the low-temperature capacity compensation mode within a very short time, which can cause relay contacts to be unable to extinguish the arc in time, or cause high-frequency spike oscillations in the MOSFET between switching states. This can result in electromagnetic interference or, in severe cases, direct burnout of power devices.

[0068] In this application, the dual-boundary-window judgment allows hysteresis to physically block oscillations. The first and second temperature thresholds are manually set action and release thresholds. System state switching no longer depends on real-time absolute temperature, but rather on the current state and the historical path of temperature changes.

[0069] As an example, during the cooling process, the system switches from a high-precision protection mode in the normal temperature range to a low-temperature capacity compensation mode. When the temperature drops from a high level, it must fall below 0°C to trigger the switch. Even if the temperature fluctuates between -0.1°C and 0.1°C, as long as it does not fall below 0°C, the system remains unchanged.

[0070] During the heating process, from the low-temperature capacity compensation mode to the high-precision protection mode in the normal temperature range, when the temperature rises from the low point, it must reach 3℃ before switching back to mode one. Between 0℃ and 3℃, even if the temperature is higher than the critical point, the system stubbornly maintains this state. This interval of 0℃ to 3℃ is the hysteresis window dead zone. Within this window, random disturbances in the temperature sensor values ​​are completely ignored, and the system state depends only on the memory retention since the last switch.

[0071] In some embodiments, S140 further includes S1404-S1405: S1404. If the current voltage is greater than the discharge cutoff voltage, then control the target battery to discharge until the current voltage drops to be equal to the discharge cutoff voltage. The dynamic real-time terminal voltage is compared with the dynamic safety boundary. Only when the safety margin is met will an enable signal be sent to the power circuit; otherwise, undervoltage protection will be immediately implemented.

[0072] Following S1404, steps C1 through C2 are included: C1. If the current voltage rebounds and rises, determine whether the current voltage exceeds the preset recovery voltage, wherein the recovery voltage is greater than the discharge cutoff voltage; In some embodiments, undervoltage debouncing and state self-locking strategies are designed in the BMS embedded underlying driver.

[0073] When a high-current discharge suddenly decreases or stops, the battery's ohmic polarization disappears instantly, and the terminal voltage immediately rebounds to a high level. Assume the discharge cutoff voltage is 2.5V, and it was 2.6V under load. Suddenly, the load decreases, and the voltage rebounds to 2.7V. Without undervoltage lockout and state-locking mechanisms, 2.7V exceeds 2.5V, thus releasing all protection limits. However, the battery's actual state of charge is still extremely low. Once a high current is applied again, the voltage will instantly drop vertically from 2.7V to 2.4V, causing over-discharge before the relay can respond.

[0074] In this application, the recovery voltage is set to be greater than the discharge cutoff voltage, creating a gray area. As an example, when the voltage bounces back to 2.7V, although higher than the cutoff line, it does not exceed the 2.8V recovery voltage. The system determines this to be a false rebound, caused by the disappearance of the polarization voltage, and not a true recovery of chemical capacity.

[0075] As an example, the voltage bounced back to 2.9V, although this exceeded the recovery voltage. The system determined this to be a real rebound and allowed the protection to be released.

[0076] When the voltage is within the gray area of ​​2.5V to 2.8V, the BMS refuses to re-execute the scan command to determine whether the device is on. It forces the drive pins of the power MOSFET or relay to remain high, ignoring any shutdown or state switching requests from upper-layer applications. The purpose is to prevent the relay from repeatedly bouncing in a vicious cycle of disconnection, resting, re-engaging, and then dropping again. Without this latching mechanism, the repeated engagement and disengagement of the relay within tens of milliseconds would generate a huge reverse induced electromotive force, directly damaging the MOSFET gate and causing severe arcing and contact erosion.

[0077] C2. If the limit is not exceeded, then the discharge circuit of the target battery is locked.

[0078] S1405. If the current voltage is less than the discharge cutoff voltage, then control the discharge circuit to the target battery to be cut off.

[0079] Once the load terminal voltage drops below the dynamic safety threshold I set, the MOSFET or relay on the main power circuit must physically trip within milliseconds to force a power outage.

[0080] This application provides a discharge management method, apparatus, computer device, and storage medium for a battery management system. The method includes: responding to a discharge management command, acquiring internal state parameters of a target battery, including the cell surface temperature of the internal cells, the current voltage of the battery, and the battery's output current; if the cell surface temperature is greater than a preset first temperature threshold, setting the discharge cutoff voltage to a preset first voltage value; if the cell surface temperature is less than the first temperature threshold, determining the corresponding battery temperature internal resistance and temperature coefficient based on the cell surface temperature; calculating the product of the battery temperature internal resistance, the temperature coefficient, and the output current to obtain a polarization voltage correction value; reducing the polarization voltage correction value based on the discharge cutoff voltage to obtain a second voltage value discharge cutoff voltage, where the polarization voltage correction value represents the portion of battery capacity whose electrochemical reaction activity is hidden due to temperature, and the second voltage value is less than the first voltage value; and performing discharge management on the target battery based on the discharge cutoff voltage and the current voltage. In this application, through a refined temperature threshold switching scheme and careful consideration of the battery's internal state, both capacity maximization and safety are achieved simultaneously at low temperatures. Addressing the significant battery capacity waste in low-temperature environments, this technology dynamically adjusts the discharge cutoff voltage based on ambient temperature and battery status. At low temperatures, it significantly increases usable capacity through a safe voltage reduction, while maintaining sufficient protection margin at high temperatures. This solves the technical problem in existing technologies where controlling the battery management system based on the current discharge cutoff voltage makes it difficult to simultaneously achieve both battery range and safety.

[0081] Figure 2 This is a schematic block diagram of a discharge management device for a battery management system provided in an embodiment of this application. Figure 2 As shown, corresponding to the above method, this application also provides a discharge management device 600 for a battery management system. This discharge management device 600 includes a unit for performing the above-described discharge management method, and can be configured in terminals such as desktop computers, tablet computers, and laptops. Specifically, please refer to... Figure 2 The discharge management device 600 of the battery management system includes an acquisition unit 601, a discharge cutoff voltage update unit 602, and a discharge management unit 603, wherein: The acquisition unit 601 is used to acquire the internal state parameters of the target battery in response to the discharge management command. The internal state parameters include the cell surface temperature of the internal cells, the current voltage of the battery, and the battery's output current to the outside. The discharge cutoff voltage update unit 602 is used to set the discharge cutoff voltage to a preset first voltage value if the surface temperature of the battery cell is greater than a preset first temperature threshold. The discharge cutoff voltage update unit 602 is further configured to: if the cell surface temperature is less than the first temperature threshold, determine the corresponding battery temperature internal resistance and temperature coefficient based on the cell surface temperature; calculate the product of the battery temperature internal resistance, the temperature coefficient, and the output current to obtain the polarization voltage correction value; reduce the polarization voltage correction value based on the discharge cutoff voltage to obtain a discharge cutoff voltage of a second voltage value, wherein the polarization voltage correction value characterizes the portion of battery capacity whose electrochemical reaction activity is hidden due to temperature, and the second voltage value is less than the first voltage value; The discharge management unit 603 is used to perform discharge management on the target battery based on the discharge cutoff voltage and the current voltage.

[0082] In some embodiments, the discharge cutoff voltage update unit 602, when performing the action of determining the corresponding battery temperature internal resistance and temperature coefficient based on the battery cell surface temperature if the cell surface temperature is less than the first temperature threshold, is specifically used for: If the cell surface temperature is less than the first temperature threshold, the corresponding battery temperature internal resistance is obtained by looking up the cell surface temperature in a preset temperature internal resistance mapping table using a lookup table method. Alternatively, the surface temperature of the battery cell can be calculated using a preset algorithm model to obtain the corresponding internal resistance of the battery at temperature. Based on the surface temperature of the battery cell, the corresponding temperature coefficient is determined.

[0083] In some embodiments, the discharge cutoff voltage update unit 602, when performing the action of querying a preset temperature internal resistance mapping table based on the cell surface temperature if the cell surface temperature is less than the first temperature threshold, specifically uses the following methods: If the surface temperature of the battery cell is less than the first temperature threshold, then the battery cell surface temperature is used to look up the value in a preset temperature resistance mapping table. If no temperature value directly corresponding to the surface temperature of the battery cell is found, select two adjacent temperature values ​​adjacent to the surface temperature of the battery cell from the table, as well as the adjacent resistance values ​​corresponding to each of the two adjacent temperature values. Based on the linear relationship between the cell surface temperature and two adjacent temperature values, the corresponding internal resistance of the battery is obtained by linearly calculating the two adjacent resistance values ​​using linear interpolation.

[0084] In some embodiments, the discharge management unit 603 performs discharge management on the target battery based on the discharge cutoff voltage and the current voltage, specifically for: If the surface temperature of the battery cell, which was originally below the first temperature threshold, rises and exceeds the first temperature threshold, it is determined whether the surface temperature of the battery cell exceeds a preset second temperature threshold, where the second temperature threshold is greater than the first temperature threshold. If the voltage is not exceeded, the discharge cutoff voltage is dynamically adjusted based on the polarization voltage correction value to obtain a discharge cutoff voltage with a second voltage value, and discharge management is performed on the target battery based on the discharge cutoff voltage and the current voltage. If the voltage is exceeded, the discharge cutoff voltage is set to the first voltage value, and discharge management is performed on the target battery based on the discharge cutoff voltage and the current voltage.

[0085] In some embodiments, the discharge management unit 603 performs discharge management on the target battery based on the discharge cutoff voltage and the current voltage, specifically for: If the current voltage is greater than the discharge cutoff voltage, then the target battery is controlled to discharge until the current voltage drops to be equal to the discharge cutoff voltage; If the current voltage is less than the discharge cutoff voltage, the discharge circuit to the target battery is cut off.

[0086] In some embodiments, if the current voltage is greater than the discharge cutoff voltage, the target battery is controlled to discharge until the current voltage drops to equal the discharge cutoff voltage. Specifically, the discharge management unit 603 is used to: If a rebound increase in the current voltage is detected, it is determined whether the current voltage exceeds a preset recovery voltage, wherein the recovery voltage is greater than the discharge cutoff voltage; If the limit is not exceeded, the discharge circuit for the target battery is locked.

[0087] In summary, the discharge management device of the battery management system in this embodiment of the application obtains the internal state parameters of the target battery in response to the discharge management command. These internal state parameters include the cell surface temperature, the current voltage of the battery, and the battery's output current. If the cell surface temperature is greater than a preset first temperature threshold, the discharge cutoff voltage is set to a preset first voltage value. If the cell surface temperature is less than the first temperature threshold, the corresponding battery temperature resistance and temperature coefficient are determined based on the cell surface temperature. The product of the battery temperature resistance, the temperature coefficient, and the output current is calculated to obtain the polarization voltage correction value. The polarization voltage correction value is reduced based on the discharge cutoff voltage to obtain a second voltage value, where the polarization voltage correction value represents the portion of battery capacity hidden due to temperature-related electrochemical reaction activity. The second voltage value is less than the first voltage value. Discharge management is performed on the target battery based on the discharge cutoff voltage and the current voltage. In this application, a refined temperature threshold switching scheme and meticulous consideration of the battery's internal state achieve a balance between maximizing capacity and ensuring safety at low temperatures. Addressing the significant battery capacity waste in low-temperature environments, this technology dynamically adjusts the discharge cutoff voltage based on ambient temperature and battery status. At low temperatures, it significantly increases usable capacity through a safe voltage reduction, while maintaining sufficient protection margin at high temperatures. This solves the technical problem in existing technologies where controlling the battery management system based on the current discharge cutoff voltage makes it difficult to simultaneously achieve both battery range and safety.

[0088] It should be noted that those skilled in the art can clearly understand that the specific implementation process of the discharge management device and each unit of the above-mentioned battery management system can be referred to the corresponding description in the foregoing method embodiments. For the sake of convenience and brevity, it will not be repeated here.

[0089] The discharge management device of the aforementioned battery management system can be implemented as a computer program, which can, for example... Figure 3 It runs on the computer device shown.

[0090] Please see Figure 3 , Figure 3 This is a schematic block diagram of a computer device 700 provided in an embodiment of this application. The computer device 700 can be a terminal or a server. The terminal can be an electronic device with communication functions, such as a smartphone, tablet, laptop, desktop computer, personal digital assistant, or wearable device. The server can be a standalone server or a server cluster composed of multiple servers.

[0091] See Figure 3The computer device 700 includes a processor 702, a memory, and a network interface 705 connected via a system bus 701. The memory may include a non-volatile storage medium 703 and internal memory 704.

[0092] The non-volatile storage medium 703 may store an operating system 7031 and a computer program 7032. The computer program 7032 includes program instructions that, when executed, cause the processor 702 to perform a discharge management method of a battery management system.

[0093] The processor 702 provides computing and control capabilities to support the operation of the entire computer device 700.

[0094] The internal memory 704 provides an environment for the operation of the computer program 7032 in the non-volatile storage medium 703. When the computer program 7032 is executed by the processor 702, the processor 702 can execute a discharge management method of a battery management system.

[0095] This network interface 705 is used for network communication with other devices. Those skilled in the art will understand that... Figure 3 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device 700 to which the present application is applied. The specific computer device 700 may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0096] The processor 702 is used to run the computer program 7032 stored in the memory to perform the following steps: In response to a discharge management command, the internal state parameters of the target battery are acquired, including the cell surface temperature of the internal cells, the current voltage of the battery, and the battery's external output current. If the surface temperature of the battery cell is greater than a preset first temperature threshold, the discharge cutoff voltage is set to a preset first voltage value. If the cell surface temperature is less than the first temperature threshold, the corresponding battery temperature internal resistance and temperature coefficient are determined based on the cell surface temperature; the product of the battery temperature internal resistance, the temperature coefficient, and the output current is calculated to obtain the polarization voltage correction value; the polarization voltage correction value is reduced based on the discharge cutoff voltage to obtain a discharge cutoff voltage of the second voltage value, wherein the polarization voltage correction value characterizes the portion of battery capacity whose electrochemical reaction activity is hidden due to temperature, and the second voltage value is less than the first voltage value; Discharge management is performed on the target battery based on the discharge cutoff voltage and the current voltage.

[0097] It should be understood that in the embodiments of this application, the processor 702 may be a central processing unit (CPU), or it may be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0098] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program includes program instructions and can be stored in a storage medium, which is a computer-readable storage medium. The program instructions are executed by at least one processor in the computer system to implement the process steps of the embodiments of the above methods.

[0099] It should be noted that the specific embodiments are merely illustrative examples intended to aid in understanding the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention. The scope of protection of this application is determined by the contents of the claims. Specific embodiments, parameter ranges, or technical features described in the specification should not be construed as undue limitation or expansion of the scope of protection of the claims. The technical effects described in the specification are only used to illustrate the innovation of the present invention. Any technical solution that does not simultaneously possess all the technical features of the present invention, even if it claims to solve the same technical problem, does not fall within the scope of protection of the present invention.

[0100] Therefore, this application also provides a storage medium. This storage medium can be a computer-readable storage medium. The storage medium stores a computer program, wherein the computer program includes program instructions. When executed by a processor, the program instructions cause the processor to perform the following steps: In response to a discharge management command, the internal state parameters of the target battery are acquired, including the cell surface temperature of the internal cells, the current voltage of the battery, and the battery's external output current. If the surface temperature of the battery cell is greater than a preset first temperature threshold, the discharge cutoff voltage is set to a preset first voltage value. If the cell surface temperature is less than the first temperature threshold, the corresponding battery temperature internal resistance and temperature coefficient are determined based on the cell surface temperature; the product of the battery temperature internal resistance, the temperature coefficient, and the output current is calculated to obtain the polarization voltage correction value; the polarization voltage correction value is reduced based on the discharge cutoff voltage to obtain a discharge cutoff voltage of the second voltage value, wherein the polarization voltage correction value characterizes the portion of battery capacity whose electrochemical reaction activity is hidden due to temperature, and the second voltage value is less than the first voltage value; Discharge management is performed on the target battery based on the discharge cutoff voltage and the current voltage.

[0101] The storage medium can be any computer-readable storage medium that can store program code, such as a USB flash drive, external hard drive, read-only memory (ROM), magnetic disk, or optical disk.

[0102] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this application.

[0103] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For example, the division of each unit is merely a logical functional division, and there may be other division methods in actual implementation. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed.

[0104] The steps in the methods of this application embodiment can be adjusted, merged, or deleted according to actual needs. The units in the apparatus of this application embodiment can be merged, divided, or deleted according to actual needs. Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0105] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, a terminal, or a network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application.

[0106] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A discharge management method for a battery management system, characterized in that, The method includes: In response to a discharge management command, the internal state parameters of the target battery are acquired, including the cell surface temperature of the internal cells, the current voltage of the battery, and the battery's external output current. If the surface temperature of the battery cell is greater than a preset first temperature threshold, the discharge cutoff voltage is set to a preset first voltage value. If the cell surface temperature is less than the first temperature threshold, the corresponding battery temperature internal resistance and temperature coefficient are determined based on the cell surface temperature; the product of the battery temperature internal resistance, the temperature coefficient, and the output current is calculated to obtain the polarization voltage correction value; the polarization voltage correction value is reduced based on the discharge cutoff voltage to obtain a discharge cutoff voltage of the second voltage value, wherein the polarization voltage correction value characterizes the portion of battery capacity whose electrochemical reaction activity is hidden due to temperature, and the second voltage value is less than the first voltage value; Discharge management is performed on the target battery based on the discharge cutoff voltage and the current voltage.

2. The method according to claim 1, characterized in that, If the cell surface temperature is less than the first temperature threshold, then the corresponding battery temperature internal resistance and temperature coefficient are determined based on the cell surface temperature, including: If the surface temperature of the battery cell is less than the first temperature threshold, the corresponding battery temperature internal resistance is obtained by looking up the battery cell surface temperature in a preset temperature internal resistance mapping table using a lookup table method. Alternatively, the surface temperature of the battery cell can be calculated using a preset algorithm model to obtain the corresponding internal resistance of the battery at temperature. Based on the surface temperature of the battery cell, the corresponding temperature coefficient is determined.

3. The method according to claim 2, characterized in that, If the cell surface temperature is less than the first temperature threshold, the corresponding battery temperature internal resistance is obtained by looking up the cell surface temperature in a preset temperature internal resistance mapping table using a lookup table method, including: If the surface temperature of the battery cell is less than the first temperature threshold, then the battery cell surface temperature is used to look up the value in a preset temperature resistance mapping table. If no temperature value directly corresponding to the surface temperature of the battery cell is found, select two adjacent temperature values ​​adjacent to the surface temperature of the battery cell from the table, as well as the adjacent resistance values ​​corresponding to each of the two adjacent temperature values. Based on the linear relationship between the cell surface temperature and two adjacent temperature values, the corresponding internal resistance of the battery is obtained by linearly calculating the two adjacent resistance values ​​using linear interpolation.

4. The method according to claim 1, characterized in that, Based on the discharge cutoff voltage and the current voltage, discharge management is performed on the target battery, including: If the surface temperature of the battery cell, which was originally below the first temperature threshold, rises and exceeds the first temperature threshold, it is determined whether the surface temperature of the battery cell exceeds a preset second temperature threshold, where the second temperature threshold is greater than the first temperature threshold. If the voltage is not exceeded, the discharge cutoff voltage is dynamically adjusted based on the polarization voltage correction value to obtain a discharge cutoff voltage with a second voltage value, and discharge management is performed on the target battery based on the discharge cutoff voltage and the current voltage. If the voltage is exceeded, the discharge cutoff voltage is set to the first voltage value, and discharge management is performed on the target battery based on the discharge cutoff voltage and the current voltage.

5. The method according to claim 1, characterized in that, Based on the discharge cutoff voltage and the current voltage, discharge management is performed on the target battery, including: If the current voltage is greater than the discharge cutoff voltage, then control the target battery to discharge until the current voltage drops to be equal to the discharge cutoff voltage; If the current voltage is less than the discharge cutoff voltage, the discharge circuit to the target battery is cut off.

6. The method according to claim 5, characterized in that, If the current voltage is greater than the discharge cutoff voltage, then control the target battery to discharge until the current voltage drops to equal the discharge cutoff voltage, including: If a rebound increase in the current voltage is detected, it is determined whether the current voltage exceeds a preset recovery voltage, wherein the recovery voltage is greater than the discharge cutoff voltage; If the limit is not exceeded, the discharge circuit for the target battery is locked.

7. A discharge management device for a battery management system, characterized in that, The device includes: The acquisition unit is used to acquire the internal state parameters of the target battery in response to the discharge management command. The internal state parameters include the cell surface temperature of the internal cells, the current voltage of the battery, and the battery's output current to the outside. The discharge cutoff voltage update unit is used to set the discharge cutoff voltage to a preset first voltage value if the surface temperature of the battery cell is greater than a preset first temperature threshold. The discharge cutoff voltage update unit is further configured to: if the cell surface temperature is less than the first temperature threshold, determine the corresponding battery temperature internal resistance and temperature coefficient based on the cell surface temperature; calculate the product of the battery temperature internal resistance, the temperature coefficient, and the output current to obtain the polarization voltage correction value; reduce the polarization voltage correction value based on the discharge cutoff voltage to obtain a discharge cutoff voltage of a second voltage value, wherein the polarization voltage correction value characterizes the portion of battery capacity whose electrochemical reaction activity is hidden due to temperature, and the second voltage value is less than the first voltage value; The discharge management unit is used to perform discharge management on the target battery based on the discharge cutoff voltage and the current voltage.

8. A discharge management computer device for a battery management system, characterized in that, The system includes a memory, a processor, and a discharge management program of a battery management system stored in the memory and executable on the processor. The processor executes the discharge management program of the battery management system to implement the steps of the discharge management method of the battery management system according to any one of claims 1 to 6.

9. A storage medium, characterized in that, The storage medium stores a program that implements a discharge management method of a battery management system, and the program that implements the discharge management method of the battery management system is executed by a processor to implement the steps of the discharge management method of the battery management system as described in any one of claims 1 to 6.

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