Battery charging control method, device, medium and product

Abstract

The application provides a battery charging control method, device, medium and product, relates to the technical field of battery management, and the method comprises the following steps: collecting the voltage, current and temperature of a target battery cell in a constant current charging stage, calculating a dynamic direct current resistance and an internal resistance growth rate. The temperature is used to determine a basic lithium precipitation boundary voltage, and the internal resistance growth rate is used to correct the lithium precipitation upper limit end voltage value. The current open circuit voltage value is determined by looking up a table based on the state of charge, temperature and internal resistance growth rate. The maximum charging current value is calculated by combining the lithium precipitation upper limit end voltage value, the current open circuit voltage value and the dynamic direct current resistance value. When the real-time charging current is greater than the maximum charging current, the difference is calculated as an adjusted current value, which is converted into a PWM signal to drive the target bypass shunt circuit to shunt. The scheme solves the technical problem that the existing charging control strategy is difficult to adapt to the change of physical characteristics in the whole life cycle of the battery.

Description

Technical Field

[0001] This application relates to the field of battery management technology, specifically to a battery charging control method, device, medium, and product. Background Technology

[0002] Lithium-ion battery packs are typically composed of multiple cells connected in series. During use, the aging rate of each cell will gradually differ. To ensure safety and extend lifespan, the battery management system needs to manage the charging process, especially to adapt to the differentiated charging needs of each cell as its performance degrades.

[0003] Existing charging control technologies already possess the ability to regulate current. Typically, the system monitors the voltage of each battery cell and adjusts the current based on a preset curve or a fixed threshold. For example, when the voltage of a certain battery cell is too high, the system will reduce the overall charging current or decrease the current flowing through that battery cell, attempting to ensure that all battery cells operate within a safe voltage range.

[0004] However, the above approach primarily relies on fixed voltage parameters to determine the adjustment timing. This strategy ignores the changes in physical characteristics caused by battery aging, particularly failing to consider the nonlinear relationship between increased internal resistance and decreased lithium plating boundary in aged cells. Adjusting current solely based on terminal voltage cannot accurately match the actual withstand capacity of aged cells, potentially leading to lithium plating damage before voltage warnings are triggered, thus accelerating performance degradation. Summary of the Invention

[0005] This application provides a battery charging control method, device, medium, and product to solve the technical problem that existing charging control strategies are difficult to adapt to changes in the physical characteristics of batteries throughout their entire life cycle.

[0006] In a first aspect, this application provides a battery charging control method, applied to a battery management system comprising a battery containing multiple cells connected in series and multiple bypass shunt circuits corresponding to the cells, comprising:

[0007] During the constant current charging phase, the real-time terminal voltage value, real-time charging current value, and real-time battery temperature value of the target cell's location are collected.

[0008] The dynamic DC internal resistance of the target cell is calculated based on the real-time terminal voltage value and the real-time charging current value, and the internal resistance growth rate of the target cell is calculated based on the dynamic DC internal resistance value and the reference internal resistance value.

[0009] The basic lithium plating boundary voltage value is determined based on the real-time temperature value of the battery region, and the basic lithium plating boundary voltage value is corrected based on the internal resistance growth rate to obtain the upper limit voltage value of lithium plating of the target cell.

[0010] Based on the current state of charge of the target cell, the real-time temperature value of the battery area, and the internal resistance growth rate, a preset multi-dimensional open-circuit voltage mapping table is queried to determine the current open-circuit voltage value of the target cell.

[0011] The maximum charging current of the target cell is calculated based on the upper limit voltage of lithium plating, the current open circuit voltage, and the dynamic DC internal resistance.

[0012] When the real-time charging current value is greater than the maximum charging current value, the difference between the real-time charging current value and the maximum charging current value is calculated to obtain the adjustment current value of the target cell. The adjustment current value is converted into a PWM control signal, and the PWM control signal is used to drive the target bypass shunt circuit corresponding to the target cell to shunt the real-time charging current value.

[0013] Optionally, the step of calculating the difference between the real-time charging current value and the maximum charging current value to obtain the adjustment current value of the target battery cell, and converting the adjustment current value into a PWM control signal, further includes:

[0014] Real-time temperature values ​​of the bypass shunt circuit in the area where the target bypass shunt circuit is located are collected.

[0015] Based on the real-time temperature value of the shunt circuit, the preset temperature-maximum duty cycle curve is queried to obtain the maximum safe duty cycle;

[0016] If the duty cycle of the PWM control signal is greater than the maximum safe duty cycle, then the final PWM control signal is generated with the maximum safe duty cycle, and the final PWM control signal is used to drive the target bypass shunt circuit corresponding to the target cell to shunt the real-time charging current value.

[0017] Calculate the maximum shunt current value based on the maximum safe duty cycle, and use the sum of the maximum charging current value and the maximum shunt current value as the target charging current value.

[0018] Send a current adjustment command to the external charging device to reduce the real-time charging current value to the target charging current value.

[0019] Optionally, the step of correcting the basic lithium plating boundary voltage value based on the internal resistance growth rate to obtain the upper limit voltage value of lithium plating for the target cell specifically includes:

[0020] The initial upper limit voltage value for lithium plating of the target cell is obtained by correcting the basic lithium plating boundary voltage value based on the internal resistance growth rate.

[0021] Calculate the voltage rise rate of the target cell within a target time window, where the target time window represents the time window from the start of the constant current charging phase to the moment when the real-time terminal voltage value is collected.

[0022] When the voltage rise rate exceeds a preset abnormal rate threshold, it is determined whether the initial lithium plating upper limit voltage value is greater than a preset safe voltage value.

[0023] When the initial lithium plating upper limit voltage value is greater than the safe voltage value, the difference between the initial lithium plating upper limit voltage value and the safe voltage value is taken as the lithium plating upper limit voltage value;

[0024] When the initial lithium plating upper limit voltage value is less than or equal to the safe voltage value, charging of the battery is stopped.

[0025] Optionally, the multidimensional open-circuit voltage mapping table set includes a standard open-circuit voltage curve, a temperature-voltage drift table, and an internal resistance change-voltage offset table. The step of querying the preset multidimensional open-circuit voltage mapping table set based on the current state of charge of the target cell, the real-time temperature value of the battery region, and the internal resistance growth rate to determine the current open-circuit voltage value of the target cell specifically includes:

[0026] Based on the current state of charge, query the standard open-circuit voltage curve to obtain the basic open-circuit voltage value;

[0027] Query the temperature-voltage drift table to obtain the temperature compensation voltage corresponding to the real-time temperature value of the battery;

[0028] Query the internal resistance change-voltage offset table to obtain the internal resistance change compensation voltage corresponding to the internal resistance growth rate;

[0029] The current open-circuit voltage value is obtained by superimposing the basic open-circuit voltage value, the temperature compensation voltage, and the internal resistance change compensation voltage.

[0030] Optionally, after calculating the maximum charging current of the target cell based on the lithium plating upper limit voltage, the current open-circuit voltage, and the dynamic DC internal resistance, the method further includes:

[0031] When the real-time charging current value is less than or equal to the maximum charging current value, the target bypass shunt circuit is controlled to remain closed.

[0032] Optionally, the step of determining the basic lithium plating boundary voltage value based on the real-time temperature value of the battery region, and correcting the basic lithium plating boundary voltage value based on the internal resistance growth rate to obtain the upper limit voltage value of lithium plating for the target cell is specifically calculated using the following formula:

[0033] Vlimit (T, SOH) = V base (T)-k×ΔR%

[0034] Among them, V limit (T, SOH) is the upper limit voltage value of lithium plating, V base (T) is the basic lithium plating boundary voltage, ΔR% is the internal resistance growth rate, and k is the preset cell aging sensitivity coefficient.

[0035] Optionally, the step of determining the current open-circuit voltage value based on the current state of charge of the target cell, and calculating the maximum charging current value of the target cell based on the lithium plating upper limit voltage value, the current open-circuit voltage value, and the dynamic DC internal resistance value, specifically uses the following formula for calculation:

[0036] I max =[V limit (T, SOH) - V ocv (SOC) ÷ R total ;

[0037] Among them, I max V is the maximum charging current value. ocv (SOC) is the current open-circuit voltage, R total The dynamic DC internal resistance is given.

[0038] In a second aspect, embodiments of this application provide a battery charging control device, which includes: one or more processors and a memory; the memory is coupled to the one or more processors, and the memory is used to store computer program code, which includes computer instructions, and the one or more processors call the computer instructions to cause the battery charging control device to perform the method described in the first aspect and any possible implementation thereof.

[0039] Thirdly, embodiments of this application provide a computer program product containing instructions that, when the computer program product is run on a battery charging control device, cause the battery charging control device to perform the method described in the first aspect and any possible implementation thereof.

[0040] Fourthly, embodiments of this application provide a computer-readable storage medium including instructions that, when executed on a battery charging control device, cause the battery charging control device to perform the method described in the first aspect and any possible implementation thereof.

[0041] In summary, one or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:

[0042] 1. By adopting the above technical solution, this application collects the voltage, current, and temperature data of the target cell in real time during the constant current charging stage, and calculates the dynamic DC internal resistance and internal resistance growth rate of the target cell accordingly, thereby quantifying the aging degree of the specific cell. The basic lithium plating boundary voltage value is determined using the real-time temperature value of the battery region, and corrected by the internal resistance growth rate of the target cell, thus obtaining the upper limit voltage value for lithium plating that conforms to the current aging state of the target cell. Furthermore, by combining the current open-circuit voltage value determined by the multi-dimensional open-circuit voltage mapping table set and the dynamic DC internal resistance value, the maximum charging current value for preventing lithium plating in the target cell is calculated. When the real-time charging current value exceeds the maximum charging current value of the target cell, independent shunt adjustment is performed through the bypass shunt circuit corresponding to the target cell. This solution can formulate personalized charging current boundaries for each individual cell with different aging degrees within the battery pack, preventing lithium plating side reactions in severely aged cells while avoiding local overcurrent damage caused by uniform control, thereby effectively solving the bottleneck effect of series battery packs and extending the overall service life of the battery pack.

[0043] 2. By adopting the above technical solution, the temperature of the shunt circuit is monitored in real time during the shunt operation, and the maximum safe duty cycle is obtained based on the temperature-maximum duty cycle curve. The PWM control signal is then limited. When the calculated duty cycle exceeds the safe threshold, the maximum safe duty cycle is forcibly used to drive the shunt circuit, preventing damage due to overheating. Simultaneously, the maximum shunt current value is calculated based on the maximum safe duty cycle, and a command is sent to the external charging device to reduce the real-time charging current value. This solution establishes a linkage mechanism between the thermal safety of the shunt circuit and the main charging current. While ensuring hardware thermal safety, it reduces the current at the source to ensure that the current flowing through the target battery cell is always maintained within the maximum charging current value, achieving dual protection of charging safety and hardware protection.

[0044] 3. By adopting the above technical solution, based on the initial lithium plating upper limit voltage value obtained by correcting the internal resistance growth rate, the voltage rise rate is further introduced as a monitoring indicator. When the voltage rise rate exceeds the abnormal rate threshold, it indicates that the cell may have abnormal polarization or a risk of poor connection. At this time, by judging the relationship between the initial lithium plating upper limit voltage value and the safe voltage value, if it is greater than the safe voltage value, the difference is deducted to further reduce the lithium plating upper limit voltage value; if it is less than or equal to the safe voltage value, charging is directly stopped. This solution provides a multi-level protection strategy for the abnormal voltage rise condition, effectively preventing the risk of the cell instantaneously touching the lithium plating boundary due to voltage change, and improving the safety of the charging process under abnormal conditions.

[0045] 4. By adopting the above technical solution, a multi-dimensional open-circuit voltage mapping table set is constructed using standard open-circuit voltage curves, temperature-voltage drift tables, and internal resistance change-voltage offset tables. When determining the current open-circuit voltage value, not only is the basic open-circuit voltage value obtained based on the current state of charge, but also the temperature compensation voltage and internal resistance change compensation voltage are consulted separately and superimposed for calculation. This solution fully considers the drift effect of temperature changes and internal resistance aging on the open-circuit voltage, eliminates the error caused by relying solely on the state of charge table lookup, and makes the calculated current open-circuit voltage value closer to the actual physical state of the cell, thereby improving the accuracy of subsequent maximum charging current value calculation and ensuring the precision of the charging control strategy. Attached Figure Description

[0046] Figure 1 This is a schematic flowchart of a battery charging control method in an embodiment of this application;

[0047] Figure 2 This is another schematic flowchart of the battery charging control method in the embodiments of this application;

[0048] Figure 3 This is a schematic diagram of the physical structure of a battery charging control device in an embodiment of this application. Detailed Implementation

[0049] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0050] In the description of the embodiments of this application, the words "for example" or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design that is described as "for example" or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design options. Rather, the use of the words "for example" or "for instance" is intended to present the relevant concepts in a specific manner.

[0051] In the description of the embodiments of this application, the term "multiple" means two or more. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the indicated technical features. Thus, a feature defined with "first," "second," or "third" may explicitly or implicitly include one or more of that feature. The terms "comprising," "including," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized. It should be noted that all data collection in this scheme is conducted after obtaining user consent.

[0052] This application provides a battery charging control method, comprising a battery management system including a battery with multiple cells connected in series and multiple bypass shunt circuits corresponding to the cells, referencing... Figure 1 , Figure 1 This is a flowchart of a battery charging control method provided in an embodiment of this application. The method includes:

[0053] It should be noted that a battery containing multiple cells connected in series refers to a battery pack composed of several individual battery cells (i.e., cells) connected end-to-end, such as the power battery pack of an electric vehicle or the battery module of an energy storage station. Its total voltage is equal to the sum of the voltages of each individual cell, and the current flowing through each series node is the same in the main circuit. Multiple bypass shunt circuits corresponding to the cells refer to a hardware circuit topology where each individual cell in the battery pack has an independent branch circuit connected in parallel. This branch circuit typically consists of a controllable switching device (such as a MOSFET) and an energy-consuming component (such as a power resistor) connected in series, used to conduct under the drive of a control signal, thereby providing a current bypass for the corresponding cell. The battery management system refers to the electronic control unit (BMS) used to monitor and control the state of the battery pack, possessing functions such as voltage and current acquisition, algorithm processing, and control of the bypass shunt circuit switches.

[0054] Specifically, this system architecture is designed to address the charging inconsistency issue caused by differences in individual cells within a series-connected battery pack. Physically, the battery management system's sampling lines are connected to the positive and negative terminals of each cell to collect individual cell voltages. Simultaneously, the battery management system's control output is connected to the switching control terminal (e.g., the gate of a MOSFET) of each bypass shunt circuit. When the battery management system determines that a particular cell (target cell) requires current regulation, it sends a control signal to the corresponding bypass shunt circuit, causing the bypass switch to close or operate with a specific duty cycle. At this point, the charging current that originally flowed through the main circuit is shunted at this node: part of the current continues to flow through the cell for charging, while the other part flows away through the bypass resistor. This architecture allows the system to independently and individually reduce the actual charging current flowing through any specific cell while keeping the main circuit charging current constant, thereby achieving refined management of cells with different aging levels or inconsistent states.

[0055] Step S101: During the constant current charging stage, the real-time terminal voltage value, real-time charging current value, and real-time battery temperature value of the area where the target cell is located are collected.

[0056] Among them, the target cell refers to any single battery cell in the battery pack that is being monitored and controlled, such as the Nth cell in a series battery pack; the constant current charging stage refers to the control stage in which the current remains relatively constant and the voltage gradually increases during the charging process; the real-time terminal voltage value refers to the potential difference between the positive and negative terminals of the battery measured at the current sampling time; the real-time charging current value refers to the magnitude of the current flowing through the main circuit at the current sampling time; and the real-time battery temperature value refers to the temperature data of the surface adjacent to the target cell collected by the temperature sensor.

[0057] Specifically, this step is typically executed periodically after the battery management system detects the connection of an external charging device and enters constant current charging mode. The battery management system utilizes high-precision analog front-end acquisition chips or independent voltage, current, and temperature sensors to inspect each series-connected cell within the battery pack at a preset sampling frequency (e.g., 1Hz or 5Hz). The system not only acquires current information from the main circuit but also simultaneously acquires the terminal voltage of each target cell and the temperature data fed back by the thermistor at the cell's physical location. This raw data, after filtering and analog-to-digital conversion, is stored in the system's temporary register, serving as real-time input for subsequent calculations of battery internal state parameters and the formulation of control strategies.

[0058] Step S102: Calculate the dynamic DC internal resistance of the target cell based on the real-time terminal voltage value and the real-time charging current value, and calculate the internal resistance growth rate of the target cell based on the dynamic DC internal resistance value and the reference internal resistance value.

[0059] Among them, the dynamic DC internal resistance value refers to the quantitative value of the total resistance to DC current flow generated by the battery under the current specific charging conditions. It comprehensively reflects the ohmic polarization resistance (caused by electrolyte, separator, current collector, etc.) and the electrochemical polarization resistance (caused by lithium ion diffusion and charge transfer). The reference internal resistance value refers to the standard internal resistance data of the battery model measured under the same temperature and state of charge (SOC) conditions as the current battery in its new state of health (BOL). It is usually stored in the system's static database. The internal resistance growth rate is a relative indicator used to quantify the degree of aging of the battery relative to its factory condition. It is usually expressed as a percentage. The larger the value, the more serious the aging (SOH decay) of the battery.

[0060] Specifically, this step is the core of online battery health status diagnosis. The battery management system first uses Ohm's law and its variant algorithms to calculate the dynamic DC internal resistance value. For example, the system can capture the instant when the charging current fluctuates slightly (e.g., the current jumps from 10A to 12A), and simultaneously record the voltage jump value (e.g., from 3.80V to 3.82V). The internal resistance is obtained by calculating the ratio of the voltage difference to the current difference (0.02V / 2A = 10mΩ); or during constant current charging, the current impedance parameters are estimated in real time using the recursive least squares (RLS) method combined with an equivalent circuit model. After obtaining the current dynamic DC internal resistance value (e.g., 15mΩ), the system will consult a pre-stored reference internal resistance table based on the current temperature (e.g., 25℃) and SOC (e.g., 50%). Assuming the reference internal resistance value of the new battery under this condition is 10mΩ, the system then executes the formula for calculating the internal resistance growth rate: (current value - reference value) / reference value × 100%. In this example, the calculation result is (15-10) / 10×100%=50%. This 50% internal resistance growth rate will be marked by the system as the current aging characteristic label of the target cell, serving as a key input for subsequent determination of whether the cell needs to have its charging voltage boundary reduced. If the calculated internal resistance growth rate of another cell is only 5%, it indicates that the cell is relatively healthy, and the charging restrictions imposed by the system will be relatively lenient.

[0061] Step S103: Determine the basic lithium plating boundary voltage value based on the real-time temperature value of the battery area, and correct the basic lithium plating boundary voltage value based on the internal resistance growth rate to obtain the upper limit voltage value of lithium plating of the target cell.

[0062] Among them, the basic lithium plating boundary voltage value refers to the maximum terminal voltage threshold that a new battery can reach at a specific temperature to avoid the negative electrode potential dropping below zero volts; the upper limit of lithium plating boundary voltage value refers to the highest safe voltage boundary that the target cell can currently reach after combining the effects of temperature and aging degradation; correction refers to the mathematical calculation of lowering the voltage boundary according to the degree of aging.

[0063] Specifically, this step establishes a safe voltage threshold to prevent lithium plating. Since low temperatures exacerbate battery polarization, increasing the risk of lithium plating, the system first uses the real-time temperature values ​​of the battery region to query a preset temperature-voltage safety curve and determine the baseline lithium plating boundary voltage at that temperature. Subsequently, considering the increased internal polarization impedance of aging cells, which makes it easier for the negative electrode potential to decrease under the same current, the system uses the calculated internal resistance growth rate as a correction factor. Generally, the higher the internal resistance growth rate, the greater the correction. The system subtracts the voltage safety margin caused by aging from the baseline lithium plating boundary voltage to calculate the final upper limit voltage for lithium plating. This value represents the physical limit voltage at which the cell will not undergo lithium plating side reactions under the current temperature and aging conditions.

[0064] Alternatively, the following formula can be used to calculate: V limit (T, SOH) = V base (T)-k×ΔR%

[0065] Among them, V limit (T, SOH) is the upper limit voltage value of lithium plating, V base (T) is the basic lithium plating boundary voltage, ΔR% is the internal resistance growth rate, and k is the preset cell aging sensitivity coefficient.

[0066] Specifically, this formula achieves precise reconstruction of the safety boundary of aged battery cells through linear correction. The determination of the coefficient k typically requires extensive offline testing in the laboratory stage. For example, researchers select batteries of the same model for accelerated aging experiments, testing the critical lithium plating voltage at internal resistance growth rates of 0%, 20%, and 50%. Assuming that at 25°C, the lithium plating boundary of a new battery (0% growth) is 4.20V, and the lithium plating boundary of an aged battery with a 50% increase in internal resistance drops to 4.10V, a voltage decrease of 0.10V, then the calculation of k is: voltage decrease / internal resistance growth rate = 0.10V / 50% = 0.002V / %. This means that for every 1% increase in internal resistance, the upper voltage limit needs to be lowered by 0.002V. In practical applications, for safety reasons, the k value is usually set slightly larger than the theoretical value, for example, 0.0025. The beneficial effect of using this formula is that it abandons the rigid mode of traditional fixed voltage control and establishes a safety voltage envelope that dynamically shrinks with the degree of aging. For aging cells with a significant increase in internal resistance, this formula will calculate a significantly reduced V. limit This system forces the current to be limited or charging to be stopped in advance, thereby eliminating the risk of lithium plating caused by excessive polarization of aging cells leading to low negative electrode potential at the physical level. This effectively prevents the battery capacity from plummeting and internal short circuit accidents, and significantly extends the safe service life of the battery pack.

[0067] Step S104: Based on the current state of charge of the target cell, the real-time temperature value of the battery area, and the internal resistance growth rate, query the preset multi-dimensional open-circuit voltage mapping table set to determine the current open-circuit voltage value of the target cell.

[0068] Among them, the current state of charge refers to the proportion of the remaining charge of the target cell to its maximum usable capacity, usually expressed as a percentage; the multidimensional open-circuit voltage mapping table set refers to the data model or lookup table system stored in the system that establishes the correspondence between open-circuit voltage and multiple influencing factors; the current open-circuit voltage value refers to the theoretical balance value of the potential difference between the positive and negative electrode materials inside the target cell under the current specific physical and chemical state.

[0069] Specifically, this step aims to obtain a high-precision voltage reference to eliminate estimation errors caused by changes in the environment and the battery's own state. Since the open-circuit voltage characteristics of a battery are not static but significantly affected by temperature and aging, traditional single-dimensional lookup table methods cannot meet the accuracy requirements of aging battery management. Therefore, this step employs a multi-dimensional lookup mechanism, using three key parameters reflecting the battery's current state—state of charge, temperature, and internal resistance growth rate—as a joint index input. The system performs searches or interpolation operations in a pre-set multi-dimensional open-circuit voltage mapping table to directly match open-circuit voltage values ​​that simultaneously meet these three conditions. This process is equivalent to locating a precise voltage coordinate in three-dimensional space, thereby determining the true static voltage of the target cell under the current complex operating conditions, providing a reliable reference for subsequent accurate calculation of current boundaries.

[0070] Step S105: Calculate the maximum charging current of the target cell based on the upper limit voltage of lithium plating, the current open circuit voltage, and the dynamic DC internal resistance.

[0071] The maximum charging current value refers to the maximum current intensity that can be injected at the current moment to ensure that the terminal voltage of the target cell does not exceed the lithium plating boundary.

[0072] Specifically, this step is based on the electrochemical mechanism to deduce the current limit. The system utilizes the voltage balance equation in circuit theory, where the terminal voltage equals the sum of the open-circuit voltage and the internal resistance voltage drop. To ensure safety, the terminal voltage cannot exceed the upper limit voltage for lithium plating. Therefore, the system calculates the difference between the upper limit voltage for lithium plating and the current open-circuit voltage, which represents the battery's maximum allowable overpotential (i.e., the allowable polarization voltage space). Subsequently, the system divides this allowable overpotential by the dynamic DC internal resistance value, and the result is the maximum charging current value. This value has a clear physical meaning: it ensures that after the voltage drop generated by the current flowing through the internal resistance is superimposed on the open-circuit voltage, the total voltage just does not touch the lithium plating red line current limit.

[0073] Alternatively, the following formula can be used for calculation:

[0074] I max =[V limit (T, SOH) - V ocv (SOC) ÷ R total ;

[0075] Among them, I max V is the maximum charging current value. ocv (SOC) is the current open-circuit voltage, R total The dynamic DC internal resistance is given.

[0076] Step S106: When the real-time charging current value is greater than the maximum charging current value, calculate the difference between the real-time charging current value and the maximum charging current value to obtain the adjustment current value of the target cell, convert the adjustment current value into a PWM control signal, and use the PWM control signal to drive the target bypass shunt circuit corresponding to the target cell to shunt the real-time charging current value.

[0077] Among them, adjusting the current value refers to the excess current portion that needs to be removed from the main current in order to meet safety constraints; the PWM control signal refers to the pulse width modulation signal, which controls the equivalent conduction degree of the switching device by changing the duty cycle of the high level; the target bypass shunt circuit refers to the branch circuit composed of power resistors and switching transistors connected in parallel with the target cell.

[0078] Specifically, this step executes the final closed-loop control action. The system compares the real-time charging current value input from the external source with the calculated maximum charging current value in real time. If the real-time input current is too large, exceeding the cell's capacity, the system defines the difference between the two as the adjustment current value. For example, suppose the real-time charging current output by the charging pile is 50A, while the maximum allowable charging current value for the aging cell, calculated according to step S105, is only 45A. The system calculates the difference to obtain an adjustment current value of 5A. This means that 5A of current must be shunted and cannot flow through the cell. The system then calculates the maximum shunting capacity of the bypass circuit when it is fully conducting as 4A (4.0V / 1Ω=4A) based on the hardware parameters of the bypass shunt circuit (such as the shunt resistor value of 1 ohm) and the current cell voltage (such as 4.0V). If the adjusted current value (5A) exceeds the bypass capacity (4A), the system will request an external reduction in the main circuit current. If the adjusted current value is within the capacity range, for example, 2A, the system calculates the duty cycle: 2A / 4A = 50%. The system generates a PWM control signal with a 50% duty cycle to drive the MOSFET in the bypass circuit to perform high-frequency switching. This causes an average of 2A of current to flow away through the bypass resistor, while the remaining 48A (50A-2A) flows through the battery cell. In this way, the actual current flowing through the target battery cell is forcibly clamped below the maximum charging current value, thereby protecting the aging battery cell.

[0079] Optionally, after calculating the difference between the real-time charging current value and the maximum charging current value to obtain the adjustment current value of the target cell, and converting the adjustment current value into a PWM control signal, this scheme can also execute steps S107-S111.

[0080] Step S107: Real-time temperature value of the shunt circuit in the area where the target bypass shunt circuit is located is collected.

[0081] The real-time temperature value of the shunt circuit refers to the local hot spot temperature data collected by temperature sensors placed near the bypass power resistor or switching transistor.

[0082] Specifically, this step is used to monitor the thermal safety status of the hardware. Since the bypass shunt circuit converts electrical energy into heat during operation, prolonged high-current shunt operation can cause a rapid increase in the local temperature of the PCB board. The system uses a dedicated NTC thermistor to read the temperature of this area in real time; for example, if the current resistor surface temperature is read as 85°C.

[0083] Step S108: Based on the real-time temperature value of the shunt circuit, query the preset temperature-maximum duty cycle curve to obtain the maximum safe duty cycle;

[0084] Among them, the temperature-maximum duty cycle curve refers to a pre-set control strategy curve that describes the negative correlation between temperature and the allowed PWM duty cycle; the maximum safe duty cycle refers to the upper limit of the PWM signal duty cycle allowed to be output at the current temperature in order to prevent the circuit from burning out.

[0085] Specifically, this step implements a thermal derating strategy. The system consults an internally stored curve table, which is typically obtained based on hardware thermal simulation tests or physical temperature rise experiments. For example, in a laboratory environment, researchers control the shunt circuit to operate continuously at different duty cycles (e.g., 10%, 20%...100%) and record the stable temperature of the circuit board when it reaches thermal equilibrium. Based on this data, a safe temperature threshold is set (e.g., 85°C is the maximum PCB tolerance temperature of 105°C minus a safety margin). When the measured temperature approaches this threshold, the curve specifies that the duty cycle must be reduced to decrease heat generation. For example, the curve might be set as follows: below 60°C, heat dissipation is good, allowing a 100% duty cycle; between 60°C and 85°C, the allowable duty cycle decreases linearly by 4% for every 1°C increase in temperature; when the temperature exceeds 85°C, the duty cycle is forced to 0% to prevent thermal runaway. In actual operation, continuing the above example, when the temperature is read as 80℃, the system calculates the maximum allowable safe duty cycle based on the curve logic (100%-(80-60)×4%=20%), which is only 20%. This means that in order to protect the circuit board from being burned out, the shunt switch cannot be turned on for more than 20% of the time.

[0086] Step S109: If the duty cycle of the PWM control signal is greater than the maximum safe duty cycle, then the final PWM control signal is generated with the maximum safe duty cycle, and the final PWM control signal is used to drive the target bypass shunt circuit corresponding to the target cell to shunt the real-time charging current value.

[0087] The final PWM control signal refers to the control signal that is actually sent to the driver of the switching device after thermal safety limitation correction.

[0088] Specifically, this step executes hardware protection actions. The system compares the theoretically required PWM duty cycle (e.g., 50%) calculated in step S106 with the maximum safe duty cycle (e.g., 20%) obtained in step S108. Since 50% > 20%, the system determines that the hardware is overheating and cannot execute the theoretical shunt command. The system forcibly clamps the duty cycle of the output signal to 20%, generating the final PWM control signal to drive the MOSFET. At this time, the bypass circuit can only actually shunt about 0.8A (assuming a full conduction shunt of 4A, 4A × 20% = 0.8A), while theoretically it should shunt 2A (4A × 50% = 2A). This forced clamping mechanism ensures that even under extreme high-temperature conditions, the shunt circuit will not burn out components or melt solder due to the execution of an overly aggressive shunt command, reflecting the design principle of "hardware safety takes precedence over control objectives."

[0089] Step S110: Calculate the maximum shunt current value based on the maximum safe duty cycle, and use the sum of the maximum charging current value and the maximum shunt current value as the target charging current value.

[0090] Among them, the maximum shunt current value refers to the maximum current shunt capability that the bypass circuit can actually provide under the current thermal constraints; the target charging current value refers to the upper limit of the main circuit current output by the external charging device requested in order to ensure the safety of the battery cell.

[0091] Specifically, this step involves reassessing the current capability. Due to thermal limitations, the shunt current capability has significantly decreased (from 2A to 0.8A). If the main circuit current remains unchanged, the cell will bear an excess 1.2A of current, leading to an overcharge risk. The system uses Ohm's law to calculate the maximum shunt current value of 0.8A (4.0V / 1Ω × 20%) based on the current cell voltage (e.g., 4.0V), bypass resistor value (1Ω), and maximum safe duty cycle (20%). The maximum allowable charging current of the cell is known to be 45A (calculated in step S105). The system adds the two: 45A + 0.8A = 45.8A. This 45.8A is the maximum current allowed through the main circuit at this point.

[0092] Step S111: Send a current adjustment command to the external charging device to reduce the real-time charging current value to the target charging current value;

[0093] Among them, the current regulation command refers to the control message sent to the charger or the next-level controller via the CAN bus or other communication protocols.

[0094] Specifically, this step achieves system-level closed-loop coordination. When the system detects that the current real-time charging current (e.g., 50A) is higher than the calculated target charging current (45.8A), it immediately sends a command to the external charging pile via the communication interface, requesting that the output current be reduced from 50A to 45.8A. When the charging pile responds and reduces the current to 45.8A, 0.8A is bypassed, and the remaining 45A flows through the battery cell, precisely meeting the cell's safety requirements. This dual regulation of "internal current sharing + external current reduction" protects both the shunt circuit from burning out and the aging battery cell from lithium deposition. This mechanism is particularly suitable for scenarios with severely aged battery packs and poor heat dissipation conditions, sacrificing some charging speed (reducing the main circuit current) to ensure the temperature safety of the entire system.

[0095] Optional, see reference Figure 2 The flowchart of another battery charging control method provided in this application embodiment shows that steps S10301-S10305 are a more specific solution to correct the basic lithium plating boundary voltage value according to the internal resistance growth rate to obtain the upper limit voltage value of lithium plating of the target cell.

[0096] Step S10301: Correct the basic lithium plating boundary voltage value according to the internal resistance growth rate to obtain the initial lithium plating upper limit voltage value of the target cell.

[0097] The initial upper limit voltage value for lithium plating refers to the theoretical voltage boundary calculated after only considering the static internal resistance aging factor, and does not yet include the safety deduction for abnormal rises in dynamic voltage.

[0098] Specifically, this step executes basic aging correction logic. Based on the internal resistance growth rate (e.g., 30%) obtained in step S102, the system uses a preset correction formula (e.g., V=V... base The base lithium plating threshold voltage (e.g., 4.20V) is lowered by -k*ΔR%. Assuming the correction factor k is 0.002V / %, the reduction is 0.002*30=0.06V, resulting in an initial lithium plating upper limit voltage of 4.14V. This value reflects the safe voltage limit of the aged cell under normal charging rates.

[0099] Step S10302: Calculate the voltage rise rate of the target cell within the target time window, where the target time window represents the time window from the start of the constant current charging stage to the time when the real-time terminal voltage value is collected.

[0100] Among them, the voltage rise rate refers to the increase in cell terminal voltage per unit time (dV / dt), which is used to characterize the speed of cell polarization; the target time window refers to a sliding or cumulative time period, which is used to smooth instantaneous fluctuations and capture the overall trend of voltage changes.

[0101] Specifically, this step aims to monitor dynamic anomalies during the charging process. The system records the voltage (e.g., 3.60V) and time point (T0) at the start of constant current charging, and the voltage (e.g., 3.90V) and time point (T1) at the current moment. Assuming a time difference (T1-T0) of 300 seconds, the voltage rise rate is (3.90-3.60) / 300 = 0.001V / s. If there is a micro-short circuit, a loose connection, or severe polarization surge caused by aging inside the cell, this rate will be significantly higher than normal. For example, if a cell's voltage spikes from 3.60V to 4.10V within 300 seconds under the same current, at a rate of 0.0016V / s, this usually means that the cell's actual capacity is very small, or its internal resistance is abnormally high, indicating a "falsely high" voltage.

[0102] Step S10303: When the voltage rise rate exceeds a preset abnormal rate threshold, determine whether the initial lithium plating upper limit voltage value is greater than a preset safe voltage value.

[0103] Among them, the abnormal rate threshold refers to the critical rate value that distinguishes normal fast charging from abnormal polarization (such as micro short circuit or lithium plating precursor). For electric vehicle batteries, this value may be set to 0.01V / s during the fast charging stage. The safety voltage value refers to a preset voltage reduction amount, which is used to further reduce the voltage boundary when an abnormal voltage rise is detected, so as to leave a greater safety margin.

[0104] Specifically, this step involves risk assessment. The determination of the safe voltage value is typically based on battery polarization characteristic testing. Researchers simulate the battery charging process at different rates in the laboratory, recording the voltage overshoot amplitude at the moment of lithium plating. For example, tests have shown that when the voltage rise rate reaches an abnormal threshold, the voltage often overshoots momentarily by about 0.15V before stabilizing or leading to lithium plating. To cover this overshoot risk, the safe voltage value is set slightly larger than this overshoot amplitude, for example, 0.2V. In actual operation, assuming the system detects that the voltage rise rate of a certain cell reaches 0.015V / s (exceeding the limit), the system reads the previously calculated initial upper limit voltage value for lithium plating (e.g., 4.15V) and logically compares it with the preset safe voltage value (0.2V). This comparison is mainly to ensure that the minuend (initial value) is large enough to be physically operable when performing subsequent subtraction operations.

[0105] Step S10304: When the initial lithium plating upper limit voltage value is greater than the safe voltage value, the difference between the initial lithium plating upper limit voltage value and the safe voltage value is taken as the lithium plating upper limit voltage value.

[0106] Specifically, this step implements a degraded operation strategy. Because the voltage rise is determined to be too rapid, to prevent the voltage from instantly breaching the lithium plating prevention threshold, the system performs the calculation: 4.15V - 0.2V = 3.95V. This 3.95V is the final upper limit voltage for lithium plating. This means that for this "virtual" cell with an exceptionally fast voltage rise, the system will no longer allow it to charge to 4.15V, but will force it to stop charging or significantly limit the current at 3.95V. In electric vehicles, this manifests as the BMS requesting the charger to reduce the current in advance, or prematurely ending the fast charging process, to prevent this poor-performing cell from overheating or plating lithium.

[0107] Step S10305: When the initial lithium plating upper limit voltage value is less than or equal to the safe voltage value, stop charging the battery;

[0108] Stopping charging means that the BMS disconnects the high-voltage relay or requests the charger to output zero current.

[0109] Specifically, this step executes a fuse protection strategy. This situation typically occurs in scenarios with extremely low temperatures or severely aged cells, where the initially calculated allowable charging voltage (the initial upper limit voltage for lithium plating) is already very low. For example, at an extreme low temperature of -30°C, to prevent lithium plating, the algorithm might calculate the upper limit of the allowable voltage for the cell to be only 3.60V. If the system then detects an abnormally rapid voltage rise (indicating extremely high internal resistance), logically, a penalty of 0.2V should be subtracted. However, under certain extreme settings, if the safe voltage value is set to a large protection threshold (for example, some strategies might set the safe voltage value to 3.8V, meaning "if the allowable voltage is below 3.8V and the voltage fluctuates wildly, don't charge"), or physically, if the voltage after subtracting the penalty is already lower than the battery's open-circuit voltage (OCV), then charging cannot proceed. In this step's logic, if the initial value (3.60V) is less than or equal to the safe voltage value (assuming this logic refers to a "deduction" of 0.2V, then 3.60V > 0.2V, and no stop is triggered; however, if the safe voltage value here refers to the "minimum allowable charging voltage," such as 3.0V, and the initial value is calculated to be lower than 3.0V for some reason), the system will determine that the cell no longer meets safe charging conditions, and forced charging will inevitably lead to lithium plating or an accident. Therefore, the system directly triggers the highest level of fault response, immediately stopping the charging of the entire battery pack.

[0110] Optionally, the multidimensional open-circuit voltage mapping table set includes a standard open-circuit voltage curve, a temperature-voltage drift table, and an internal resistance change-voltage offset table. Steps S10401-S10404 are a more specific embodiment of step S104 in this scheme.

[0111] Optionally, the following methods can be used to obtain standard open-circuit voltage curves, temperature-voltage drift tables, and internal resistance change-voltage offset tables:

[0112] The method for obtaining the standard open-circuit voltage curve is as follows: Select a new battery sample in the early stage of its life (BOL) and place it in a constant temperature chamber, setting the ambient temperature to the standard temperature (e.g., 25°C). After fully charging the battery, discharge it at a very low rate (e.g., C / 20 or less) with a constant current until the cutoff voltage, or use a pulse discharge method (discharge 5% SOC and then let it rest for 1 hour). Record the voltage change with capacity during the discharge process, or record the voltage point at the end of the resting period. Normalize the capacity coordinates to SOC (0%~100%), and then plot the SOC-OCV curve at 25°C, which is the standard open-circuit voltage curve.

[0113] The method for obtaining the temperature-voltage drift table is as follows: Using the same new battery samples described above, place them at different ambient temperature points (e.g., covering -30℃ to 60℃, in 10℃ increments). At each temperature point, repeat the OCV testing procedure described above to obtain the SOC-OCV curve at that temperature. Then, using the standard curve at 25℃ as a benchmark, calculate the voltage difference corresponding to the same SOC point at other temperatures. For example, when SOC=50%, the difference between the OCV at 10℃ and the OCV at 25℃ is the drift amount at that temperature point. Organize the voltage differences corresponding to each temperature point and each SOC point into a two-dimensional lookup table, which is the temperature-voltage drift table.

[0114] Scheme for obtaining the internal resistance change-voltage deviation table: Select battery samples of the same model for accelerated aging cycle experiments (e.g., charge-discharge cycles at high temperatures). During the aging process, periodically (e.g., every 100 cycles) measure the DC internal resistance of the battery and calculate the internal resistance growth rate. Simultaneously, at each measurement point, perform an OCV test at a standard temperature (25°C) on the aged battery. Compare the OCV curve of the aged battery with the standard OCV curve of a new battery (internal resistance growth rate 0%) to calculate the voltage deviation at the same SOC point. Establish a mapping relationship between the internal resistance growth rate and the voltage deviation. For example, record the voltage deviation corresponding to internal resistance growth rates of 10%, 20%, 30%, etc., and compile them into a table, which is the internal resistance change-voltage deviation table.

[0115] Step S10401: Query the standard open-circuit voltage curve based on the current state of charge to obtain the basic open-circuit voltage value;

[0116] The basic open-circuit voltage value refers to the theoretical voltage value obtained solely from the SOC table.

[0117] Specifically, this step obtains the voltage reference. The system first estimates the current SOC of the target cell using the ampere-hour integration method combined with the Kalman filter algorithm, for example, an SOC of 50%. Then, the system consults the standard open-circuit voltage curve stored in Flash memory. This curve is typically obtained in a laboratory constant temperature chamber (25°C) by discharging a fully charged battery with a small current of C / 20 to the cutoff voltage, recording the voltage change trajectory with capacity. Assume that the base open-circuit voltage value corresponding to 50% SOC is 3.650V obtained from the table.

[0118] Step S10402: Query the temperature-voltage drift table to obtain the temperature compensation voltage corresponding to the real-time temperature value of the battery;

[0119] Temperature-compensated voltage refers to the voltage change caused by the temperature term in the Nernst equation.

[0120] Specifically, this step corrects for the effects of temperature. The system reads the current real-time battery temperature, for example, 10°C. The system then consults a temperature-voltage drift table. This table is obtained by measuring the OCV at the same SOC point at different temperature points (e.g., -20°C, -10°C, 0°C, 10°C...50°C) and calculating the difference between this OCV and the OCV at 25°C. For example, experiments show that at 10°C, the internal electrochemical potential energy of the battery changes, causing the OCV to be 0.005V lower than at 25°C. Therefore, the temperature compensation voltage obtained from the table is -0.005V.

[0121] Step S10403: Query the internal resistance change-voltage offset table to obtain the internal resistance change compensation voltage corresponding to the internal resistance growth rate;

[0122] Among them, the internal resistance change compensation voltage refers to the amount of equilibrium potential drift caused by the loss of active material or structural change of positive and negative electrode materials.

[0123] Specifically, this step corrects for the effects of aging. The system reads the internal resistance growth rate calculated in step S102, for example, 30%. The system consults the internal resistance change-voltage offset table. This table is obtained by performing OCV tests on batteries at different aging stages in accelerated aging experiments (e.g., internal resistance increases of 10%, 20%, 30%, etc.) and comparing the OCV curves with those of new batteries. Typically, aging causes a drift in the lithium intercalation potential of the cathode material. For example, experiments have shown that when the internal resistance increases by 30%, at SOC 50%, the OCV of the aged battery is 0.010V higher than that of the new battery (this depends on the specific cathode and anode material system; some systems experience an increase in OCV after aging, while others experience a decrease). Assume the internal resistance change compensation voltage obtained from the table is +0.010V.

[0124] Step S10404: The basic open-circuit voltage value, the temperature compensation voltage, and the internal resistance change compensation voltage are superimposed and calculated to obtain the current open-circuit voltage value;

[0125] Specifically, this step synthesizes the final true voltage. The system sums the three components: 3.650V (base value) + (-0.005V) (temperature correction) + 0.010V (aging correction) = 3.655V. This 3.655V is the true open-circuit voltage of the target cell at the current 10℃ and 30% aging condition. Compared to the 3.650V obtained by directly looking up a table, this corrected value eliminates the 0.005V error. Although the error seems small, when calculating the maximum charging current, the tiny deviation in voltage can be amplified by the internal resistance (usually only a few milliohms), leading to significant differences in the current calculation results. Therefore, this multi-stage correction is crucial for ensuring charging safety.

[0126] Optionally, step S112 can be performed after step S106.

[0127] Step S112: When the real-time charging current value is less than or equal to the maximum charging current value, control the target bypass shunt circuit to remain in the off state.

[0128] In this context, the off state refers to the state in which the switching device (such as MOSFET) in the bypass shunt circuit is continuously open (OFF), and the duty cycle of the PWM control signal is 0%.

[0129] Specifically, this step is a pass-through branch in the control logic. The system compares the real-time charging current value (e.g., 20A) of the external input with the calculated maximum charging current value (e.g., 45A). Since 20A < 45A, it indicates that the current main circuit current is well within the safe tolerance range of the battery cell, and no intervention is required. The system sets the PWM control signal to a low level or an inactive state to ensure that the bypass circuit is not conducting. At this time, all 20A current flows through the inside of the battery cell for charging, ensuring charging efficiency and avoiding unnecessary heat loss from the bypass resistor.

[0130] The battery charging control device in the embodiments of this invention is described below from the perspective of hardware processing. Please refer to [link / reference needed]. Figure 3 This is a schematic diagram of the physical structure of a battery charging control device in an embodiment of this application.

[0131] It should be noted that, Figure 3 The structure of the battery charging control device shown is merely an example and should not impose any limitations on the functionality and scope of use of the embodiments of the present invention.

[0132] like Figure 3As shown, the battery charging control device includes a CPU 301, which can perform various appropriate actions and processes according to a program stored in the read-only memory ROM 302 or a program loaded from the storage section 308 into the random access memory RAM 303, such as executing the methods described in the above embodiments. The RAM 303 also stores various programs and data required for system operation. The CPU 301, ROM 302, and RAM 303 are interconnected via a bus 304. An I / O interface 305 is also connected to the bus 304.

[0133] The following components are connected to I / O interface 305: input section 306 including audio input devices, push-button switches, etc.; output section 307 including a liquid crystal display (LCD) and audio output devices, indicator lights, etc.; storage section 308 including a hard disk, etc.; and communication section 309 including a network interface card such as a LAN (Local Area Network) card, modem, etc. Communication section 309 performs communication processing via a network such as the Internet. Drive 310 is also connected to I / O interface 305 as needed. Removable media 311, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., are installed on drive 310 as needed so that computer programs read from them can be installed into storage section 308 as needed.

[0134] In particular, according to embodiments of the present invention, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of the present invention include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing computer programs for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via communication section 309, and / or installed from removable medium 311. When the computer program is executed by CPU 301, it performs the various functions defined in the present invention.

[0135] It should be noted that specific examples of computer-readable storage media may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), flash memory, optical fiber, portable compact disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this invention, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0136] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. Each block in a flowchart or block diagram may represent a module, program segment, or portion of code, which contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those shown in the drawings.

[0137] Specifically, the battery charging control device in this embodiment includes a processor and a memory. The memory stores a computer program, and when the computer program is executed by the processor, it implements the battery charging control method provided in the above embodiment.

[0138] In another aspect, the present invention also provides a computer-readable storage medium, which may be included in the battery charging control device described in the above embodiments; or it may exist independently and not assembled into the battery charging control device. The storage medium carries one or more computer programs that, when executed by a processor of the battery charging control device, cause the battery charging control device to implement the battery charging control method provided in the above embodiments.

[0139] 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. This program can be stored in a computer-readable storage medium, and when executed, it can include the processes described in the above method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as ROM or random access memory (RAM), magnetic disks, or optical disks.

Claims

1. A battery charge control method applied to a battery management system comprising a battery including a plurality of battery cells connected in series and a plurality of bypass circuits corresponding to the battery cells, characterized by, The method includes: During the constant current charging phase, the real-time terminal voltage value, real-time charging current value, and real-time battery temperature value of the target cell's location are collected. The dynamic DC internal resistance of the target cell is calculated based on the real-time terminal voltage value and the real-time charging current value, and the internal resistance growth rate of the target cell is calculated based on the dynamic DC internal resistance value and the reference internal resistance value. The basic lithium plating boundary voltage value is determined based on the real-time temperature value of the battery region, and the basic lithium plating boundary voltage value is corrected based on the internal resistance growth rate to obtain the upper limit voltage value of lithium plating of the target cell. Based on the current state of charge of the target cell, the real-time temperature value of the battery area, and the internal resistance growth rate, a preset multi-dimensional open-circuit voltage mapping table is queried to determine the current open-circuit voltage value of the target cell. The maximum charging current of the target cell is calculated based on the upper limit voltage of lithium plating, the current open circuit voltage, and the dynamic DC internal resistance. When the real-time charging current value is greater than the maximum charging current value, the difference between the real-time charging current value and the maximum charging current value is calculated to obtain the adjustment current value of the target cell. The adjustment current value is converted into a PWM control signal, and the PWM control signal is used to drive the target bypass shunt circuit corresponding to the target cell to shunt the real-time charging current value.

2. The method of claim 1, wherein, The process of calculating the difference between the real-time charging current value and the maximum charging current value to obtain the adjustment current value of the target battery cell, converting the adjustment current value into a PWM control signal, and then further including: Real-time temperature values ​​of the bypass shunt circuit in the area where the target bypass shunt circuit is located are collected. Based on the real-time temperature value of the shunt circuit, the preset temperature-maximum duty cycle curve is queried to obtain the maximum safe duty cycle; If the duty cycle of the PWM control signal is greater than the maximum safe duty cycle, then the final PWM control signal is generated with the maximum safe duty cycle, and the final PWM control signal is used to drive the target bypass shunt circuit corresponding to the target cell to shunt the real-time charging current value. Calculate the maximum shunt current value based on the maximum safe duty cycle, and use the sum of the maximum charging current value and the maximum shunt current value as the target charging current value. Send a current adjustment command to the external charging device to reduce the real-time charging current value to the target charging current value.

3. The method of claim 1, wherein, The step of correcting the basic lithium plating boundary voltage value based on the internal resistance growth rate to obtain the upper limit voltage value of lithium plating for the target cell specifically includes: The initial upper limit voltage value for lithium plating of the target cell is obtained by correcting the basic lithium plating boundary voltage value based on the internal resistance growth rate. Calculate the voltage rise rate of the target cell within a target time window, where the target time window represents the time window from the start of the constant current charging phase to the moment when the real-time terminal voltage value is collected. When the voltage rise rate exceeds a preset abnormal rate threshold, it is determined whether the initial lithium plating upper limit voltage value is greater than a preset safe voltage value. When the initial lithium plating upper limit voltage value is greater than the safe voltage value, the difference between the initial lithium plating upper limit voltage value and the safe voltage value is taken as the lithium plating upper limit voltage value; When the initial lithium plating upper limit voltage value is less than or equal to the safe voltage value, charging of the battery is stopped.

4. The method of claim 1, wherein, The multidimensional open-circuit voltage mapping table set includes a standard open-circuit voltage curve, a temperature-voltage drift table, and an internal resistance change-voltage offset table. The step of determining the current open-circuit voltage value of the target cell by querying the preset multidimensional open-circuit voltage mapping table set based on the target cell's current state of charge, the real-time temperature value of the battery region, and the internal resistance growth rate specifically includes: Based on the current state of charge, query the standard open-circuit voltage curve to obtain the basic open-circuit voltage value; Query the temperature-voltage drift table to obtain the temperature compensation voltage corresponding to the real-time temperature value of the battery; Query the internal resistance change-voltage offset table to obtain the internal resistance change compensation voltage corresponding to the internal resistance growth rate; The current open-circuit voltage value is obtained by superimposing the basic open-circuit voltage value, the temperature compensation voltage, and the internal resistance change compensation voltage.

5. The method of claim 1, wherein, After calculating the maximum charging current of the target cell based on the upper limit voltage of lithium plating, the current open-circuit voltage, and the dynamic DC internal resistance, the process further includes: When the real-time charging current value is less than or equal to the maximum charging current value, the target bypass shunt circuit is controlled to remain closed.

6. The method of claim 1, wherein, The basic lithium plating boundary voltage value is determined based on the real-time temperature value of the battery region, and then corrected according to the internal resistance growth rate to obtain the upper limit voltage value of lithium plating for the target cell. Specifically, the following formula is used for calculation: V limit (T, SOH) = V base (T) - k x ΔR%; wherein V limit (T, SOH) is the lithium precipitation upper limit voltage value, V base (T) is the basic lithium precipitation boundary voltage, ΔR% is the internal resistance growth rate; k is a preset battery aging sensitivity coefficient.

7. The method according to claim 6, characterized in that, The current open-circuit voltage value is determined based on the current state of charge of the target battery cell, and the maximum charging current value of the target battery cell is calculated based on the upper limit voltage value of lithium plating, the current open-circuit voltage value, and the dynamic DC internal resistance value, specifically using the following formula: I max = [V limit (T, SOH) - V ocv (SOC)] ÷ R total ; where I max is the maximum charging current value, V ocv (SOC) is the current open circuit voltage, R total is the dynamic DC internal resistance.

8. A battery charging control device, characterized in that, The battery charging control device includes: one or more processors and a memory; the memory is coupled to the one or more processors, the memory is used to store computer program code, the computer program code including computer instructions, and the one or more processors call the computer instructions to cause the battery charging control device to perform the method as described in any one of claims 1-7.

9. A computer-readable storage medium comprising instructions, characterized in that, When the instruction is executed on the battery charging control device, the battery charging control device performs the method as described in any one of claims 1-7.

10. A computer program product, characterized in that, When the computer program product is run on the battery charging control device, it causes the battery charging control device to perform the method as described in any one of claims 1-7.

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