A method and apparatus for power control of a battery cell

Abstract

This application relates to a battery cell power control method and apparatus. The method includes: during the operation of a first target battery cell among multiple battery cells, collecting the surface temperature and remaining charge percentage of the first target battery cell at preset time intervals; determining a preset operating power corresponding to the surface temperature and remaining charge percentage of the first target battery cell in an operating capability table, thereby obtaining a first target operating power for the first target battery cell; and controlling the first target battery cell to operate at the first target operating power at preset time intervals. Since the operating capability table has preset correspondences between preset surface temperatures, preset remaining charge percentages, and preset operating powers of multiple battery cells, this method can control the first target battery cell to operate at a first target operating power that matches its state conditions, significantly improving the battery cell's lifespan and safety.

Description

Technical Field

[0001] This application relates to the field of battery cell technology, and in particular to a battery cell power control method and apparatus. Background Technology

[0002] With the rapid development of battery cell technology, lithium iron phosphate (LFP) batteries have emerged. Due to their advantages such as high safety, long cycle life, and low cost, LFP batteries are widely used in energy storage systems, electric vehicles, and portable power banks. However, the charge and discharge performance of LFP batteries is affected by temperature and the remaining state of charge (SOC). Therefore, charging and discharging LFP batteries at high power under unsuitable conditions will negatively impact their lifespan and safety. Summary of the Invention

[0003] Therefore, it is necessary to provide a battery cell power control method, device, computer equipment, computer-readable storage medium, and computer program product that can improve the service life and safety of battery cells, in response to the above-mentioned technical problems.

[0004] In a first aspect, this application provides a cell power control method applied in the control module of a battery management system. The battery management system is connected to multiple cells of the same model that share a common operating capacity table. The operating capacity table has a preset correspondence between preset surface temperatures, preset remaining charge percentages, and preset operating power of the multiple cells. The method includes:

[0005] During the operation of the first target battery cell, the surface temperature and remaining charge percentage of the first target battery cell are collected at preset time intervals; the first target battery cell is one of multiple battery cells.

[0006] In the operating capacity table, the preset operating power corresponding to the surface temperature and remaining charge percentage of the first target cell is determined to obtain the first target operating power of the first target cell.

[0007] At preset intervals, the first target battery cell is controlled to operate at the first target operating power.

[0008] Secondly, this application also provides a cell power control device, applied in the control module of a battery management system. The battery management system is connected to multiple cells of the same model that share a common operating capacity table. The operating capacity table has a preset correspondence between preset surface temperatures, preset remaining charge percentages, and preset operating power of the multiple cells. The device includes:

[0009] The data acquisition module is used to collect the surface temperature and remaining charge percentage of the first target battery cell at preset time intervals during the operation of the first target battery cell; the first target battery cell is one of multiple battery cells.

[0010] The determination module is used to determine the preset operating power corresponding to the surface temperature and remaining charge percentage of the first target cell in the operating capacity table, so as to obtain the first target operating power of the first target cell;

[0011] The control module is used to control the first target cell to operate at the first target operating power at preset time intervals.

[0012] Thirdly, this application also provides a computer device. The computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement some or all of the steps described in any method of the first aspect of the embodiments of this application.

[0013] Fourthly, this application also provides a computer-readable storage medium. The computer-readable storage medium stores a computer program thereon, which, when executed by a processor, implements some or all of the steps described in any method of the first aspect of the embodiments of this application.

[0014] Fifthly, this application also provides a computer program product. The computer program product includes a computer program that, when executed by a processor, implements some or all of the steps described in any method of the first aspect of the embodiments of this application.

[0015] The aforementioned battery cell power control method, apparatus, computer equipment, computer-readable storage medium, and computer program product, because the operating capability table has a preset correspondence between preset surface temperatures, preset remaining charge percentages, and preset operating power of multiple battery cells, can control the first target battery cell to operate at a first target operating power corresponding to its surface temperature and remaining charge percentage. Furthermore, the first target operating power is updated at preset intervals, thereby ensuring that the charging or discharging power of the battery cell never exceeds the safe power threshold of the battery cell under the current conditions. This maximizes the charging or discharging power of the battery cell while ensuring its safety, and also improves the battery cell's service life. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the battery management system in one embodiment;

[0018] Figure 2 This is a flowchart illustrating a cell power control method in one embodiment;

[0019] Figure 3 This is a structural block diagram of a battery cell power control device in one embodiment;

[0020] Figure 4 This is an internal structural diagram of a computer device in one embodiment;

[0021] Figure 5 This is a diagram of the internal structure of a computer device in another embodiment. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0023] As described in the background section, the charge and discharge performance of LFP cells is affected by various factors such as surface temperature and remaining charge percentage. In low-temperature environments, the internal resistance of LFP cells increases, necessitating strict control of the allowable charge and discharge current; otherwise, lithium plating may occur, accelerating capacity decay. Conversely, in high-temperature environments, excessive charge and discharge currents can exacerbate side reactions, shortening the lifespan of LFP cells. Therefore, this embodiment provides a cell power control method that can improve the safety and lifespan of LFP cells.

[0024] The cell power control method provided in this application embodiment can be applied to, for example... Figure 1In the application environment shown, the battery management system 100 includes a control module 102, multiple battery cells 104, a current detection module 106, a voltage detection module 108, a charge / discharge power transistor 110, a temperature sensor 112, and an external charge / discharge interface 114. The control module 102 is connected to the multiple battery cells 104, the current detection module 106, the voltage detection module 108, the temperature sensor 112, and the charge / discharge power transistor 110. The current detection module 106 is connected in series with the multiple battery cells 104 in the main charge / discharge circuit. The charge / discharge power transistor 110 is connected to the external charge / discharge interface 114, so that the multiple battery cells 104 can be connected to the external charge / discharge interface 114 through the charge / discharge power transistor 110. The current detection module 106 is used to collect the current of the battery cell 104, the voltage detection module is used to collect the voltage of the battery cell 104, the temperature sensor 112 is used to collect the surface temperature of the battery cell 104, and the charge / discharge power transistor 110 is used to turn on or off the charging / discharging paths of multiple battery cells 104 to the external charging / discharging interface 114 (the charging path corresponds to the external power supply, and the discharging circuit corresponds to the applied electrical load). Optionally, the control module 102 can be a microcontroller unit (MCU). Optionally, the charge / discharge power transistor 110 can be a metal-oxide-semiconductor field-effect transistor (MOSFET). Optionally, the external charging / discharging interface 114 can be a single interface or include both an external charging interface and an external discharging interface.

[0025] In one exemplary embodiment, such as Figure 2 As shown, a cell power control method is provided, which is applied to... Figure 1 The control module of the battery management system connects to multiple battery cells of the same model, which share a common operating capacity table. The operating capacity table pre-sets the correspondence between preset surface temperatures, preset remaining charge percentages, and preset operating power for the multiple battery cells. The method includes steps 202 to 206. Wherein:

[0026] Step 202: During the operation of the first target cell, the surface temperature and remaining charge percentage of the first target cell are collected at preset time intervals; the first target cell is one of multiple cells.

[0027] The battery management system can be integrated into the power bank.

[0028] Optionally, multiple cells can be LFP cells of the same model. Multiple cells constitute a cell pack.

[0029] Optionally, the operating capability table can be predefined based on the cell's model specification and measured electrical parameter data. Multiple cells of the same model share a single operating capability table; that is, one operating capability table corresponds to one cell model, and the battery management system stores only one operating capability table.

[0030] Since the operating capacity table has a preset correspondence between the preset surface temperature, preset remaining charge percentage and preset operating power of multiple cells, it can be understood as a three-dimensional array table.

[0031] The operation of a battery cell includes its charging and discharging processes. Optionally, the charging process can be understood as an external power source supplying power to the cell, allowing it to store electrical energy; the discharging process can be understood as the cell releasing electrical energy to a load to supply power to that load. Based on this, the operating power meter of the first target battery cell can be understood as including its charging capacity meter and discharging capacity meter.

[0032] The surface temperature of a battery cell refers to the temperature of the outer casing surface of the battery cell.

[0033] Alternatively, the surface temperature of the battery cell can be obtained by a temperature sensor in the battery management system.

[0034] The remaining capacity percentage of a battery cell refers to the percentage of its current remaining usable capacity relative to its rated total capacity.

[0035] The operating power of a battery cell refers to its charging or discharging power. When the battery cell is charging, the operating power refers to its charging power; when the battery cell is discharging, the operating power refers to its discharging power.

[0036] Optionally, the preset time can be 100ms, 150ms, 200ms or other lengths.

[0037] The purpose of collecting the surface temperature and remaining charge percentage of the first target battery cell at preset intervals is to obtain the first target operating power of the first target battery cell in the operating capacity table in real time, so as to control the first target battery cell to operate at the first target operating power in real time. Based on this, it can be ensured that the charging power or discharging power of the battery cell will never exceed the safe power threshold of the battery cell under the current state conditions.

[0038] Step 204: In the operating capacity table, determine the preset operating power corresponding to the surface temperature and remaining charge percentage of the first target cell, and obtain the first target operating power of the first target cell.

[0039] The control module can retrieve a matching preset operating power from the operating capability table based on the surface temperature and remaining charge percentage of the first target battery cell, and determine the preset operating power as the first target operating power of the first target battery cell. Based on this, the first target battery cell can operate at a charging power or discharging power that matches its current condition.

[0040] Optionally, in the operating capacity table, the preset operating power that matches the preset surface temperature and preset remaining charge percentage is the maximum operating power of the cell under the preset surface temperature and preset remaining charge percentage conditions. Based on this, the first target operating power of the first target cell is the maximum operating power corresponding to its surface temperature and remaining charge percentage, and this maximum operating power will not exceed the safe power threshold of the cell under the current conditions.

[0041] Optionally, the battery management system may also store the user-defined maximum operating power of the battery cell. Thus, the first target operating power is the minimum value between the preset operating power and the user-defined maximum operating power. That is to say, the control module will ensure that the operating power of the first target battery cell will not exceed the user-defined maximum operating power to meet the user's operating requirements for the battery cell.

[0042] Since the surface temperature and remaining charge percentage of the first target cell are collected at preset time intervals, the first target operating power of the first target cell is also obtained from the operating capacity table at preset time intervals.

[0043] Step 206: Control the first target cell to operate at the first target operating power at preset time intervals.

[0044] This can be achieved by adjusting the duty cycle of the charging and discharging power transistor at preset intervals, so as to control the first target cell to operate at the first target operating power based on the adjusted duty cycle; the adjusted duty cycle corresponds to the first target operating power.

[0045] Optionally, the control module can adjust the duty cycle of the charging and discharging power transistor at preset time intervals using proportional-integral-derivative (PID) control or a comparator.

[0046] It is easy to understand that if the first target operating power of the first target cell determined in the operating capacity table remains unchanged after a preset time interval, the duty cycle of the charging and discharging power transistors should also remain unchanged.

[0047] Since the control module controls the first target battery cell to operate at the first target operating power at preset time intervals, the charging and discharging power of the first target battery cell is updated in real time at preset time intervals. This ensures that the charging or discharging power of the battery cell will never exceed the safe power threshold of the battery cell under the current conditions.

[0048] Optionally, the control module can also collect the voltage of the first target cell at preset time intervals, so that if the surface temperature of the first target cell is greater than 55°C or the voltage is greater than 3.65V, the operation of the first target cell will be stopped.

[0049] It is easy to understand that since the first target cell is one of multiple cells, the operating power of other cells can also be controlled using the methods described in steps 202-206 above. That is to say, the first target cell in this embodiment does not specifically refer to any one cell, and the cell power control method provided in this embodiment is applicable to multiple cells. Based on this, the control module can control each cell to operate at the corresponding target operating power at preset time intervals based on the surface temperature and remaining charge percentage of each cell.

[0050] In the above-mentioned cell power control method, since the operating capacity table has a preset correspondence between preset surface temperature, preset remaining charge percentage and preset operating power of multiple cells, it is possible to control the first target cell to operate at a first target operating power corresponding to its surface temperature and remaining charge percentage. Furthermore, the first target operating power is updated at preset intervals, thereby ensuring that the charging power or discharging power of the cell will never exceed the safe power threshold of the cell under the current conditions. This maximizes the charging power or discharging power of the cell while ensuring cell safety, and also improves the lifespan of the cell.

[0051] As can be seen, since the first target operating power is determined based on the operating capacity table, it avoids the first target cell from continuing to charge and discharge at high power under harsh conditions such as high temperature, low temperature, high remaining charge percentage, and low remaining charge percentage. This effectively suppresses aging mechanisms such as lithium plating and cathode material structure collapse in multiple cells within the battery management system. Using the cell power control method provided in this embodiment, under charge and discharge conditions of 25℃ and 1P, the cell's capacity retention rate can still exceed 70% after 8000 charge and discharge cycles. Compared with traditional technical solutions that use fixed charge and discharge power or simple segmented constant current, this embodiment improves the service life of multiple cells by more than 70%.

[0052] In an exemplary embodiment, the operating capability table has a preset correspondence between preset temperature ranges, preset remaining power ranges, and preset operating power of multiple battery cells.

[0053] The above-mentioned operating capacity table determines the operating power corresponding to the surface temperature and remaining charge percentage of the first target cell, thus obtaining the first target operating power of the first target cell, including:

[0054] Based on the surface temperature of the first target cell, determine the preset temperature range corresponding to the first target cell in the operating capability table;

[0055] Based on the remaining percentage of the first target cell's charge, determine the preset charge range corresponding to the first target cell in the operating capacity table;

[0056] In the operating capacity table, the preset operating power corresponding to the preset temperature range and preset remaining power range of the first target battery cell is determined, and the first target operating power of the first target battery cell is obtained.

[0057] The preset temperature ranges in the operating capacity table are divided according to a fixed temperature step size. Optionally, the fixed temperature step size can be 3℃, 5℃, 6℃, or other temperature differences. When the fixed temperature step size is 5℃, the preset temperature ranges in the operating capacity table correspond to one temperature range for every 5℃ difference.

[0058] The preset remaining power range in the operating capacity table is divided according to a fixed power step size. Optionally, the fixed power range can be 3%, 5%, 6%, or other power differences. When the fixed power step size is 5°C, the preset remaining power range in the operating capacity table corresponds to a power range for every 5% difference.

[0059] In this embodiment, the operating capability table has a preset correspondence between multiple preset temperature ranges, preset remaining power ranges, and preset operating power of the battery cells. Based on this, after determining the preset temperature range and preset power range corresponding to the first target battery cell in the operating capability table, the preset operating power corresponding to the preset temperature range and preset remaining power range of the first target battery cell can be determined in the operating capability table to obtain the first target operating power of the first target battery cell. Since the operating capability table has multiple preset temperature ranges and multiple preset remaining power ranges, the computational complexity of the control module in determining the first target operating power can be reduced. By avoiding delay phenomena, it can be ensured that the charging power or discharging power of the battery cell will never exceed the safe power threshold of the battery cell under the current state conditions. Under the premise of ensuring the safety of the battery cell, the charging power or discharging power of the battery cell is maximized, and the service life of the battery cell can also be improved.

[0060] In an exemplary embodiment, determining the preset operating power corresponding to the preset temperature range and preset remaining power range of the first target battery cell in the operating capability table, and obtaining the first target operating power of the first target battery cell, includes:

[0061] In the operational capability table, determine the upper and lower temperature limits of the preset temperature range corresponding to the first target cell;

[0062] In the operating capacity table, determine the preset operating power corresponding to the preset temperature range and preset remaining power range of the first target battery cell;

[0063] In the operating capacity table, determine the previous preset operating power corresponding to the previous preset temperature range and the preset remaining power range; the previous preset operating power is less than the preset operating power.

[0064] Based on the surface temperature of the first target cell, the corresponding upper temperature limit, the corresponding lower temperature limit, the corresponding previous preset operating power, and the corresponding preset operating power, the first target operating power of the first target cell is determined.

[0065] In an exemplary embodiment, the formula for calculating the first target operating power of the first target battery cell is:

[0066] P_limit1=P1+(P2-P1)×(T_now-T1) / (T2-T1)

[0067] Where P_limit1 represents the first target operating power, P1 represents the previous preset operating power, P2 represents the preset operating power, T_now represents the surface temperature, T1 represents the lower limit of the temperature, and T2 represents the upper limit of the temperature.

[0068] The temperature difference between the upper and lower temperature limits of the preset temperature range corresponds to the fixed temperature step size of the preset temperature range. For example, when the fixed temperature step size is 5°C, the temperature difference between the upper and lower temperature limits of the preset temperature range is 5°C.

[0069] The previous preset temperature range refers to the adjacent temperature range of the preset temperature range, where the temperature value of the adjacent temperature range is lower than that of the preset temperature range. For example, if the preset temperature range is 25℃~30℃, then the previous preset temperature range is 20℃~25℃.

[0070] Optionally, the previous preset temperature range refers to the adjacent temperature range of the preset temperature range, provided that it corresponds to the same preset remaining power range. That is, the preset temperature range and the previous preset temperature range can have the same preset remaining power range in the operating capacity table.

[0071] In this embodiment, to avoid the adverse situation of current surge caused by power abrupt change at the boundary of the preset temperature range, linear interpolation calculation is introduced between adjacent temperature ranges in the operating capacity table to obtain the first target operating power of the first target cell. Based on this, the first target operating power can be continuously and smoothly transitioned with temperature changes, reducing the electrical stress impact on the first target cell and improving the cell's lifespan by improving cell safety.

[0072] In an exemplary embodiment, determining the preset operating power corresponding to the preset temperature range and preset remaining power range of the first target battery cell in the operating capability table, and obtaining the first target operating power of the first target battery cell, includes:

[0073] In the operational capability table, determine the upper limit and lower limit of the remaining power for the preset remaining power range corresponding to the first target cell;

[0074] In the operating capacity table, determine the preset operating power corresponding to the preset temperature range and preset remaining power range of the first target battery cell;

[0075] In the operating capacity table, determine the previous preset operating power corresponding to the previous preset remaining power range and the preset temperature range; the previous preset operating power is less than the preset operating power.

[0076] Based on the remaining percentage of the first target battery cell, the corresponding upper limit of the remaining battery cell, the corresponding lower limit of the remaining battery cell, the corresponding previous preset operating power, and the corresponding preset operating power, the first target operating power of the first target battery cell is determined.

[0077] In an exemplary embodiment, the formula for calculating the first target operating power of the first target battery cell is:

[0078] P_limit1=P1+(P2-P1)×(SOC_now-SOC1) / (SOC2-SOC1)

[0079] Where P_limit1 represents the first target operating power, P1 represents the previous preset operating power, P2 represents the preset operating power, SOC_now represents the remaining battery percentage, SOC 1 represents the lower limit of the remaining battery, and SOC 2 represents the upper limit of the remaining battery.

[0080] The upper and lower limits of the remaining power in the preset remaining power range correspond to the fixed power step size of the preset remaining power range. For example, when the fixed power step size is 5%, the power difference between the upper and lower limits of the remaining power in the preset remaining power range is 5%.

[0081] The previous preset remaining battery range refers to the adjacent remaining battery range of the preset remaining battery range, where the battery value of the adjacent remaining battery range is less than that of the preset remaining battery range. For example, if the preset remaining battery range is 55% to 60%, then the previous preset remaining battery range is 50% to 55%.

[0082] Optionally, the previous preset remaining power range refers to the adjacent remaining power range of the preset remaining power range, provided that it corresponds to the same preset temperature range. That is, the preset remaining power range and the previous preset remaining power range may correspond to the same preset temperature range in the operating capacity table.

[0083] In this embodiment, to avoid the adverse situation of current surge caused by power abrupt change at the boundary of the preset remaining power range, linear interpolation calculation is introduced between adjacent remaining power ranges in the operating capacity table to obtain the first target operating power of the first target cell. Based on this, the first target operating power can be continuously and smoothly transitioned with the change of remaining power, reducing the electrical stress impact on the first target cell and improving the cell's lifespan by improving cell safety.

[0084] Optionally, a bilinear interpolation algorithm can be used to obtain the first target operating power along the dimensions of the preset surface temperature and preset remaining charge percentage in the operating capability table. That is, firstly, the four adjacent grid corners of the surface temperature and remaining charge percentage of the first target cell in the operating capability table are located; then, based on these four adjacent grid corners, a linear interpolation is performed in the direction of the preset surface temperature and the direction of the preset remaining charge percentage, respectively; finally, a unique and smoothly transitioning first target operating power is obtained, thereby avoiding sudden changes in operating power and ensuring the physical rationality of the lookup result of the first target cell based on the operating capability table.

[0085] For example, when the surface temperature of the first target cell at the current time point falls within a preset temperature range, and the remaining percentage of the first target cell at the current time point also falls within a preset remaining percentage range, a bilinear interpolation algorithm can be used: First, perform a first interpolation on the preset operating power corresponding to two adjacent preset temperature ranges in the direction of remaining percentage; then, perform a second interpolation on the preset operating power corresponding to two adjacent preset remaining percentage ranges in the direction of surface temperature. This will yield a unique operating power limit value, i.e., the first target operating power.

[0086] In one exemplary embodiment, the method further includes:

[0087] After the first target cell completes each full operation, at the instant the first target cell switches from the operating state to the stationary state or the reverse operating state, the voltage change and current change of the first target cell are measured.

[0088] Based on the voltage and current changes, the actual internal resistance of the first target cell is obtained;

[0089] Determine the internal resistance growth rate based on the actual and initial internal resistance values ​​of the first target cell.

[0090] The aging coefficient of the first target cell is determined based on the internal resistance growth rate and the first empirical coefficient.

[0091] The above-mentioned operating capacity table determines the preset operating power corresponding to the surface temperature and remaining charge percentage of the first target cell, thus obtaining the first target operating power of the first target cell, including:

[0092] In the operating capacity table, the preset operating power corresponding to the surface temperature and remaining charge percentage of the first target cell is determined to obtain the initial target operating power of the first target cell;

[0093] Based on the initial target operating power and aging coefficient, the first target operating power of the first target cell is determined; the first target operating power is less than the initial target operating power.

[0094] Completing a full operation process refers to completing either a full charging process or a full discharging process. A full charging process means that the first target cell has been charged to the charging cutoff state, at which point the first target cell can no longer be charged; a full discharging process means that the first target cell has been discharged to the discharging cutoff state, at which point the first target cell can no longer be discharged.

[0095] When the first target cell switches from the operating state to the idle state, it means that the first target cell stops operating and enters a standby or shutdown state.

[0096] The first target cell switching from the operating state to the reverse operating state means that the operating state of the first target cell has reversed. That is to say, the reverse operating state corresponding to the charging state is the discharging state, and the reverse operating state corresponding to the discharging state is the charging state.

[0097] The initial internal resistance value of the first target cell refers to the internal resistance value measured under standard test conditions when the first target cell is in an unused state or when the number of charge-discharge cycles is less than the cycle number threshold.

[0098] Optionally, the actual internal resistance of the first target cell can be obtained by measuring the ratio between the voltage change and the current change of the first target cell at the moment of charge-discharge switching.

[0099] Optionally, the voltage change can be obtained by the control module through the voltage detection module, and the current change can be obtained by the control module through the current detection module.

[0100] As the number of charge-discharge cycles of the first target cell increases, the internal resistance of the first target cell will increase. Therefore, the actual internal resistance of the first target cell is greater than the initial internal resistance.

[0101] Optionally, the first empirical coefficient can be 0.2 to 0.5.

[0102] In an exemplary embodiment, the formula for calculating the actual internal resistance of the first target cell is:

[0103] R_est=ΔV / ΔI

[0104] Where R_est represents the actual internal resistance of the first target cell, ΔV represents the voltage change of the first target cell at the moment of charge-discharge switching, and ΔI represents the current change of the first target cell at the moment of charge-discharge switching.

[0105] To ensure the accuracy of the actual internal resistance value of the first target cell, the charging and discharging switching moment corresponding to the first target cell should occur in an extremely short time, for example, within a few milliseconds to tens of milliseconds.

[0106] In an exemplary embodiment, the formula for calculating the aging coefficient of the first target cell is:

[0107] α = 1 - k×(η_R - 1)

[0108] Where α represents the aging coefficient of the first target cell, k represents the first empirical coefficient, and η_R represents the internal resistance growth rate.

[0109] In this embodiment, the initial target operating power corresponds to the preset operating power in the operating capacity table; while the first target operating power is the operating power obtained after reducing the initial target operating power based on the aging coefficient. The larger the aging coefficient, the greater the reduction effect on the initial target operating power, that is, the larger the difference between the first target operating power and the initial target operating power. It can be understood that the larger the aging coefficient, the greater the limiting effect on the first target operating power.

[0110] As can be seen from the calculation formula of the aging coefficient of the first target cell, its aging coefficient is less than 1. Therefore, based on the aging coefficient of the first target cell, the initial target operating power obtained from the operating capability table can be reduced to a lower first target operating power. In other words, under the same preset surface temperature and the same preset remaining charge percentage, the first target cell can operate at a lower first target operating power than the preset operating power in the operating capability table. Based on this, it is possible to avoid the adverse situation where the first target cell continues to operate at a higher operating power after aging, which would affect its safety and lifespan.

[0111] In this embodiment, as the actual internal resistance of the first target battery cell increases and its capacity decreases with the number of charging cycles, the aging coefficient of the first target battery cell can be determined. This allows for the reduction of the preset operating power corresponding to the first target battery cell in the operating capacity table, ensuring that the determined first target operating power is lower than the preset operating power in the operating capacity table. Based on this, after multiple charge-discharge cycles, the operation of the first target battery cell can be controlled by a modified, more suitable first target operating power, avoiding the use of a preset operating power that is already too high for the first target battery cell. This prevents the first target battery cell from operating at a high power after aging, which could negatively impact its safety and lifespan. It can be seen that this embodiment can prevent the actual internal resistance of the first target battery cell from increasing due to aging, leading to excessive actual power, thus further delaying the aging process and achieving optimized protection for multiple cells throughout the entire lifecycle of the battery management system.

[0112] In an exemplary embodiment, determining the aging coefficient of the first target cell based on the internal resistance growth rate and a first empirical coefficient includes:

[0113] The initial aging coefficient of the first target cell is determined based on the internal resistance growth rate and the first empirical coefficient.

[0114] An aging adjustment coefficient is generated based on the number of full-discharge cycles of the first target cell; there is a positive correlation between the number of full-discharge cycles and the degree to which the aging adjustment coefficient weakens the initial aging coefficient;

[0115] The initial aging coefficient of the first target cell is adjusted based on the aging adjustment coefficient to obtain the aging coefficient of the first target cell; the aging coefficient is less than the initial aging coefficient.

[0116] The term "full-discharge count" for the first target cell refers to the cumulative number of times the remaining charge percentage of the first target cell drops to 0%. The control module can retrieve the full-discharge count of the first target cell from the battery management system's operation log.

[0117] Since the lifespan of a battery cell is more affected by full discharge than by shallow discharge, the more full discharge cycles there are, the greater the aging coefficient will be.

[0118] Optionally, the aging adjustment coefficient is 0 to 1.

[0119] In another exemplary embodiment, the above-mentioned generation of the aging adjustment coefficient based on the number of full-discharge cycles of the first target cell includes:

[0120] Obtain the full-discharge temperature of the first target cell under historical full-discharge events with a number of full-discharge cycles;

[0121] Based on the full-discharge temperature under historical full-discharge events, the average full-discharge temperature of the first target cell is determined.

[0122] An aging adjustment coefficient is generated based on the number of full-discharge cycles and the average temperature of full-discharge cycles of the first target cell. There is a positive correlation between the average temperature of full-discharge cycles and the degree to which the aging adjustment coefficient weakens the initial aging coefficient.

[0123] The average temperature at full discharge refers to the average temperature when the remaining charge percentage of the first target cell drops to 0%.

[0124] Since high-temperature full discharge will further affect the service life of the battery cells, under the same number of full discharge cycles, the higher the average temperature of full discharge, the greater the aging coefficient.

[0125] Optionally, the aging factor = initial aging factor × number of full-time cycles × average temperature during full-time cycles.

[0126] In this embodiment, the aging coefficient of the first target battery cell is determined by the number of full-discharge cycles and the average temperature during full-discharge events in history. Based on this, the determination process of the aging coefficient can simultaneously consider the frequency of full-discharge events of the first target battery cell and the thermal environment at the time of occurrence, so that the aging coefficient can more accurately reflect the service life loss of the first target battery cell. Therefore, based on the more accurate aging coefficient, the first target operating power of the first target battery cell can also be more accurate, so that the control module can accurately control the operating power of the first target battery cell in the future.

[0127] In one exemplary embodiment, the method further includes:

[0128] When the remaining charge percentage of the first target cell is 0% or 100%, determine the cumulative charge and discharge capacity of the first target cell;

[0129] The nominal capacity value of the first target cell is corrected based on the cumulative charge and discharge capacity to obtain the corrected nominal capacity value.

[0130] During the operation of the first target battery cell, the surface temperature and remaining charge percentage of the first target battery cell are collected at preset time intervals, including:

[0131] During the operation of the first target battery cell, the surface temperature of the first target battery cell is collected at preset time intervals, and the remaining percentage of the first target battery cell is determined based on the initial remaining percentage of the first target battery cell and the corrected nominal capacity value at preset time intervals.

[0132] Here, the cumulative charge and discharge capacity can be understood as the cumulative charging capacity or the cumulative discharging capacity. Based on this, when the remaining capacity percentage of the first target cell is 0%, the cumulative discharging capacity of the first target cell is determined; when the remaining capacity percentage of the first target cell is 100%, the cumulative charging capacity of the first target cell is determined.

[0133] Alternatively, the cumulative charge and discharge capacity of the first target cell can be determined after each complete operation of the first target cell.

[0134] Optionally, the cumulative charge and discharge capacity of the first target cell can be determined by the ampere-hour integration method.

[0135] The nominal capacity of the first target cell can be understood as the factory capacity of the first target cell in an unused state.

[0136] Before correcting for the nominal capacity of the first target cell, the formula for calculating the remaining percentage of charge in the cell is as follows:

[0137] SOC_now = SOC_initial-∫I·dt / C_nominal

[0138] Wherein, SOC_now represents the remaining percentage of the first target cell, SOC_initial represents the initial remaining percentage of the first target cell during this operation, ∫I•dt represents the cumulative charge and discharge capacity of the first target cell from the initial time point to the current time point during this operation, and C_nominal represents the nominal capacity value of the first target cell.

[0139] During the use of the first target battery cell, accumulated errors such as current sampling drift can cause errors in its nominal capacity value. Therefore, this embodiment corrects the nominal capacity value to determine the remaining percentage of charge in the first target battery cell. This improves the accuracy of the remaining percentage calculation and makes the first target operating power determined in the operating capacity table more accurate, thereby enhancing the safety and lifespan of the first target battery cell.

[0140] In one exemplary embodiment, the method further includes:

[0141] The voltage of each cell in multiple battery cells is collected at preset time intervals;

[0142] Based on the surface temperature and voltage of multiple cells, at least one equalizing cell is identified among the multiple cells to participate in the equalization process.

[0143] The remaining charge percentage of each equalization cell is balanced; in at least one equalization cell after the remaining charge percentage is balanced, the voltage difference between the maximum and minimum voltage values ​​is less than or equal to the voltage difference threshold.

[0144] The differential voltage threshold can be 10mV, 20mV, 30mV, or other voltage values.

[0145] In an exemplary embodiment, the method of determining at least one equalizing cell to participate in the equalization process based on the surface temperature and voltage of multiple cells includes:

[0146] Based on the surface temperatures of multiple battery cells, a second target battery cell with the maximum surface temperature is determined; the second target battery cell is one of the multiple battery cells.

[0147] If the maximum surface temperature of the second target cell is greater than a first temperature threshold, at least one cell among the multiple cells whose voltage is greater than a first voltage threshold is identified as at least one balanced cell; or,

[0148] Based on the surface temperatures of multiple battery cells, a third target battery cell with the minimum surface temperature is determined; the third target battery cell is one of the multiple battery cells.

[0149] If the minimum surface temperature of the third target cell is less than the second temperature threshold, at least one cell among the multiple cells whose voltage is greater than the second voltage threshold is identified as at least one balanced cell.

[0150] Wherein, the first temperature threshold is greater than the second temperature threshold; the first voltage threshold is greater than the second voltage threshold.

[0151] Since the balancing activation voltage corresponds to the first voltage threshold when the surface temperature of the second target cell with the maximum surface temperature is greater than the first temperature threshold, and the balancing activation voltage corresponds to the second voltage threshold when the surface temperature of the third target cell with the minimum surface temperature is less than the second temperature threshold, it can be seen that the balancing activation voltage of the battery management system corresponds to the maximum or minimum surface temperature of multiple cells. Based on this, it can be understood that the balancing activation voltage in this embodiment dynamically changes with the surface temperature; the balancing activation voltage is higher in high-temperature environments and lower in low-temperature environments. For example, the balancing activation voltage is 3.42V when the maximum surface temperature is higher, and 3.35V when the minimum surface temperature is lower. Therefore, the balancing process for multiple cells in this embodiment has high flexibility and adaptability to extreme temperature environments.

[0152] It can also be understood that, in this embodiment, under high temperature conditions, the equalization turn-on voltage is dynamically calculated based on the maximum surface temperature of multiple cells, and the cells with voltages greater than the equalization turn-on voltage are identified as equalization cells. Correspondingly, the same principle applies under low temperature conditions, so it will not be elaborated here.

[0153] The first target battery cell and the second target battery cell may be the same battery cell or they may not be the same battery cell. Similarly, the first target battery cell and the third target battery cell may be the same battery cell or they may not be the same battery cell.

[0154] The second target cell is the one with the highest surface temperature among the multiple cells.

[0155] Optionally, the first temperature threshold can be 40°C, 45°C, 50°C, 55°C, or other temperature values.

[0156] Optionally, the first voltage threshold can be 3.38V, 3.42V, 3.47V, 3.52V, or other voltage values.

[0157] Optionally, the second temperature threshold can be 8°C, 10°C, 12°C, 15°C, or other temperature values.

[0158] Optionally, the second voltage threshold can be 3.30V, 3.35V, 3.40V, 3.43V, or other voltage values. It is only necessary to ensure that the value of the second voltage threshold is less than the value of the first voltage threshold.

[0159] The first voltage threshold is greater than the average equalization turn-on voltage of the cell type of the first target cell; the second voltage threshold is less than the average equalization turn-on voltage of the cell type of the first target cell. For example, if the cell type of the first target cell is an LFP cell, the cell specification sheet typically specifies an average equalization turn-on voltage of 3.38V, so the average equalization turn-on voltage of the LFP cell can be considered to be 3.38V. In this case, the first voltage threshold could be, for example, 3.42V, and the second voltage threshold could be, for example, 3.35V.

[0160] A balanced cell refers to a cell among multiple cells that participates in the process of balancing the remaining percentage of battery capacity. Cells whose voltage does not exceed a first voltage threshold or a second voltage threshold will not participate in the remaining percentage balancing process. For example, if a high-temperature cell is present and the voltage of the first target cell is greater than the first voltage threshold, or if a low-temperature cell is present and the voltage of the first target cell is greater than the second voltage threshold, then the first target cell will also participate in the remaining percentage balancing process.

[0161] Optionally, balancing at least one balancing cell can be performed when the remaining charge percentage of multiple cells is 90% to 100%, that is, when multiple cells are fully charged, or when multiple cells are in a quiescent state.

[0162] In this embodiment, when the maximum surface temperature of the second target cell is greater than the first temperature threshold, at least one cell with a voltage greater than the first voltage threshold is identified as at least one balancing cell. This means that the balancing activation voltage of the multiple cells is increased relative to the average balancing activation voltage. This avoids the situation where a cell is still undergoing balancing even when a high-temperature cell is present, preventing additional heat generation in the battery management system due to balancing, which could negatively impact the safety and lifespan of the multiple cells. In other words, it reduces the risk of thermal runaway in the multiple cells. When the maximum surface temperature of the third target cell is less than the second temperature threshold, since the polarization voltage of the cell is higher in low-temperature environments, at least one cell with a voltage greater than the second voltage threshold is identified as at least one balancing cell. This means that the balancing activation voltage of the multiple cells is reduced relative to the average balancing activation voltage. This allows the balancing voltage to participate in the balancing process earlier, avoiding adverse effects on the cell's charging and discharging capabilities in low-temperature environments.

[0163] Optionally, the first voltage threshold and the second voltage threshold can be fixed preset thresholds, or they can be dynamically changed according to the corresponding maximum or minimum surface temperature. When the first and second voltage thresholds are dynamically changing values, a piecewise linear function or a continuous function can be used to establish the mapping relationship between the surface temperature and the equalization activation voltage. The first voltage threshold is obtained based on the maximum surface temperature, and the second voltage threshold is obtained based on the minimum surface temperature.

[0164] In an exemplary embodiment, the method of determining at least one equalizing cell to participate in the equalization process based on the surface temperature and voltage of multiple cells includes:

[0165] Based on the surface temperatures of multiple cells, a second target cell with the maximum surface temperature is determined.

[0166] The equalization turn-on voltage is determined based on the maximum surface temperature and the temperature coefficient.

[0167] Among multiple cells, at least one cell with a voltage greater than the equalization activation voltage is identified as at least one equalization cell participating in the equalization process.

[0168] The temperature coefficient can be 0.002V / ℃, 0.003V / ℃, 0.004V / ℃, or other empirical values.

[0169] Optionally, when the maximum surface temperature is less than or equal to 45°C, the formula for calculating the equalization turn-on voltage can be:

[0170] V_balance_on = 3.38+a×(T_now-25)

[0171] Where V_balance_on represents the balance turn-on voltage, a represents the temperature coefficient, and T_now represents the surface temperature.

[0172] Alternatively, when the maximum surface temperature exceeds 45°C, the formula for calculating the equalization turn-on voltage can be:

[0173] V_balance_on = 3.38+a×(T_now-25)+b×(T_now-45)

[0174] Where b represents the temperature compensation coefficient. The temperature compensation coefficient can be 0.01V / ℃, 0.015V / ℃, 0.02V / ℃, or other empirical values.

[0175] In this embodiment, when the maximum surface temperature exceeds 45°C, the equalization threshold voltage increases more rapidly. This design is based on the fact that in the high-temperature region of the battery cell (>45°C), the cell is more sensitive to the additional heat generated by the equalization current. Therefore, a more aggressive increase in the equalization threshold voltage is needed to preemptively limit or halt the equalization process, preventing thermal runaway. Thus, the temperature compensation coefficient is essentially an "additional offset," which makes the slope of the equalization threshold voltage curve in the high-temperature range steeper, thereby achieving a stronger protection effect for the battery cell than a purely linear formula.

[0176] In one exemplary embodiment, the method further includes:

[0177] Based on the remaining percentage of power in multiple battery cells, determine the maximum and minimum remaining percentage of power.

[0178] When the minimum remaining battery percentage is less than the first percentage threshold, the differential pressure threshold is less than the first preset differential pressure value;

[0179] When the minimum remaining power percentage is greater than the second percentage threshold, the differential pressure threshold is greater than the second preset differential pressure value; when the first percentage threshold is less than the second percentage threshold, the first preset differential pressure value is less than the second preset differential pressure value.

[0180] The maximum remaining battery percentage refers to the maximum value obtained by comparing the remaining battery percentages of multiple battery cells. Similarly, the minimum remaining battery percentage refers to the minimum value obtained by comparing the remaining battery percentages of multiple battery cells.

[0181] Alternatively, the maximum remaining power percentage refers to the specific value of the remaining power percentage corresponding to the cell with the highest remaining power percentage; the minimum remaining power percentage refers to the specific value of the remaining power percentage corresponding to the cell with the lowest remaining power percentage.

[0182] Optionally, the first percentage threshold can be 15%, 20%, 25%, or other percentage values.

[0183] Optionally, the second percentage threshold can be 75%, 80%, 85%, or other percentage values.

[0184] Optionally, the first preset differential voltage value can be 8mV, 10mV, 15mV, or other voltage values.

[0185] Optionally, the second preset differential voltage value can be 25mV, 30mV, 35mV, or other voltage values.

[0186] Based on the characteristics of LFP cells, in the low-charge range, the voltage-SOC curve of an LFP cell is very flat. This means that even if there is a significant difference in the remaining charge percentage between two LFP cells, their voltages are likely to be very close. Therefore, if the voltage difference threshold is set too high when the remaining charge percentage of an LFP cell is at its lowest, the two LFP cells at low charge levels may not meet the threshold condition, thus failing to trigger equalization processing. Therefore, when the remaining charge percentage is low, the voltage difference threshold can be appropriately reduced; that is, when the minimum remaining charge percentage is less than a first percentage threshold, the voltage difference threshold should be less than a first preset voltage difference value.

[0187] Based on the characteristics of LFP cells, their voltage-SOC curve is relatively steep in the high-capacity range. This means that even if the remaining capacity percentage of two LFP cells is small, they may still have a large voltage difference. Therefore, if the voltage difference threshold is set too low when the remaining capacity percentage of LFP cells is high, the large voltage difference between the two high-capacity LFP cells will lead to frequent or false triggering of the equalization process, resulting in unnecessary waste of battery management system resources. Therefore, when the remaining capacity percentage is high, the voltage difference threshold can be appropriately increased. That is, when the minimum remaining capacity percentage is greater than a second percentage threshold, the voltage difference threshold should be greater than a second preset voltage difference value.

[0188] In this embodiment, based on the remaining percentage of power in multiple battery cells, a maximum and a minimum remaining percentage are determined. Therefore, when the minimum remaining percentage is less than a first percentage threshold, the differential pressure threshold is less than a first preset differential pressure value; conversely, when the minimum remaining percentage is greater than a second percentage threshold, the differential pressure threshold is greater than a second preset differential pressure value. Based on this, when the remaining percentage of power in a battery cell is low, the differential pressure threshold is lowered to increase the trigger sensitivity of the equalization process; conversely, when the remaining percentage of power in a battery cell is high, the differential pressure threshold is increased to decrease the trigger sensitivity of the equalization process. This ensures the accuracy of the equalization process, improves the safety and lifespan of multiple battery cells, and reduces ineffective equalization time to avoid wasting battery management system resources.

[0189] In an exemplary embodiment, the method of determining at least one equalizing cell to participate in the equalization process based on the surface temperature and voltage of multiple cells includes:

[0190] If the difference between the maximum and minimum remaining power percentages is greater than a second preset voltage difference, at least one equalizing cell is determined from among the multiple cells to participate in the equalization process, based on the surface temperature and voltage of each cell.

[0191] In one exemplary embodiment, the method further includes:

[0192] During the process of equalizing the remaining charge percentage of at least one equalized cell, the surface temperature of multiple cells is compared with a third temperature threshold.

[0193] If the comparison result shows that the surface temperature of at least one cell is greater than the third temperature threshold, the balancing process for the remaining charge percentage of at least one balanced cell is stopped until the surface temperature of each cell in the multiple cells is less than the third temperature threshold, and then the remaining charge percentage of at least one balanced cell is rebalanced; the third temperature threshold is greater than the fourth temperature threshold.

[0194] In another exemplary embodiment, the above-mentioned process of stopping the balancing of the remaining charge percentage of at least one balanced cell when the comparison result shows that the surface temperature of at least one cell is greater than the third temperature threshold, and then re-balancing the remaining charge percentage of at least one balanced cell when the surface temperature of each cell in the plurality of cells is less than the third temperature threshold, includes:

[0195] If the comparison result shows that the surface temperature of at least one cell is greater than the third temperature threshold, the balancing process for the remaining charge percentage of at least one balanced cell is stopped until the surface temperature of each cell in the multiple cells is less than the fourth temperature threshold for a certain period of time, and then the remaining charge percentage of at least one balanced cell is rebalanced.

[0196] The third temperature threshold can be the same as the second temperature threshold. Optionally, the third temperature threshold can be 50°C, and the fourth temperature threshold can be 45°C, as long as the third temperature threshold is greater than the fourth temperature threshold.

[0197] Optionally, the time threshold can be 30 seconds, 35 seconds, 40 seconds, or other lengths.

[0198] In this embodiment, if the temperature of any cell is high, all equalization processes are immediately suspended until the temperature drops before resuming equalization. This avoids multiple cells having to withstand additional heat generated by equalization processes in high-temperature environments, thereby improving the safety and lifespan of multiple cells.

[0199] Optionally, in this embodiment, the balancing process for at least one balancing cell can be passive balancing, and the balancing current during passive balancing is typically fixed by the cell's discharge resistor. Based on this, in an exemplary embodiment, each cell is connected to a balancing power transistor, and the method further includes:

[0200] In the process of equalizing the remaining charge percentage of at least one equalizing cell, the maximum and minimum surface temperature values ​​are determined based on the surface temperatures of multiple cells, and the maximum and minimum voltage values ​​are determined based on the voltages of multiple cells.

[0201] When the temperature difference between the maximum and minimum surface temperatures is less than the temperature difference threshold, the duty cycle of the equalization power transistor is reduced to reduce the equalization current flowing into at least one equalization cell; when the voltage difference between the maximum and minimum voltages is greater than the voltage difference threshold, the duty cycle of the equalization power transistor is kept at 100%.

[0202] Reducing the balancing current flowing into at least one balancing cell is to reduce the heat generated by the balancing cell; while maintaining the duty cycle of the balancing power transistor at 100% is to improve the efficiency of the balancing process.

[0203] In an exemplary embodiment, controlling the first target cell to operate at a first target operating power at preset time intervals includes:

[0204] When the remaining charge percentage of the first target battery cell is within a first preset percentage range, the first target operating power is reduced based on a first limiting coefficient to control the first target battery cell to operate at a second target operating power; the first target operating power is greater than the second target operating power, and the minimum value of the first preset percentage range is greater than or equal to 90%;

[0205] When the remaining charge percentage of the first target cell is within the second preset percentage range, the target operating power is reduced based on the second limiting coefficient to control the first target cell to operate at the third target operating power or stop discharging; the first target operating power is greater than the third target operating power, and the maximum value of the second preset percentage range is less than or equal to 10%.

[0206] The first preset percentage range can be 90% to 100%.

[0207] Optionally, the second preset percentage range can be 0% to 10%.

[0208] Both the first and second constraint coefficients are less than 1. Optionally, the first constraint coefficient can be 0.2, 0.4, 0.7, or other values; the second constraint coefficient can be 0.1, 0.3, 0.5, or other values. The relationship between the first and second constraint coefficients is not limited.

[0209] The first and second limiting coefficients can be calibrated based on actual test data from multiple battery cells. For example, if a battery cell has the characteristic of low capacity retention at low temperatures, i.e., it is a low-temperature sensitive cell, then the second limiting coefficient can be greater than the first limiting coefficient.

[0210] Optionally, when the remaining charge percentage of the first target battery cell is within a first preset percentage range and the external power supply provides power to the first target battery cell, the first target operating power can be reduced based on a first limiting coefficient to control the first target battery cell to operate at a second target operating power.

[0211] Optionally, when the remaining charge percentage of the first target cell is within a second preset percentage range and the first target cell is discharging to the electrical load, the target operating power can be reduced based on a second limiting coefficient to control the first target cell to operate at a third target operating power or stop discharging.

[0212] Optionally, within the first preset percentage range and the second preset percentage range, the remaining power percentage can be further subdivided into step sizes to further reduce the first target operating power step by step.

[0213] In this embodiment, during the charging process of the first target battery cell, when the remaining charge percentage of the first target battery cell is located in the charging end region, and during the discharging process of the first target battery cell, when the remaining charge percentage of the first target battery cell is located in the discharging end region, the operating power of the first target battery cell is reduced to limit the operating power of the first target battery cell, so that the charging current flowing through the first target battery cell can decrease gradually, thereby improving the safety and service life of the first target battery cell.

[0214] In an exemplary embodiment, the first preset percentage range is 90% to 100%. When the remaining percentage of the first target battery cell is within the first preset percentage range, reducing the first target operating power based on a first limiting coefficient to control the first target battery cell to operate at a second target operating power includes:

[0215] When the remaining charge percentage of the first target cell is ≥90% and ≤95%, the second target operating power is 65%~75% of the first target operating power;

[0216] When the remaining charge percentage of the first target cell is >95% and ≤98%, the second target operating power is 35% to 45% of the first target operating power;

[0217] When the remaining charge percentage of the first target cell is >98% and ≤100%, the second target operating power is 15% to 25% of the first target operating power.

[0218] In an exemplary embodiment, the second preset percentage range is 0% to 10%. When the remaining charge percentage of the first target cell is within the second preset percentage range, reducing the target operating power based on a second limiting coefficient to control the first target cell to operate at a third target operating power includes:

[0219] When the remaining charge percentage of the first target cell is >5% and ≤10%, the third target operating power is 45%~55% of the first target operating power;

[0220] When the remaining charge percentage of the first target cell is >3% and ≤5%, the third target operating power is 25% to 35% of the first target operating power;

[0221] If the remaining charge percentage of the first target cell is ≥0% and ≤3%, the third target operating power is 5% to 15% of the first target operating power or is 0%.

[0222] The third target operating power is 0% of the first target operating power, which means controlling the first target cell to stop discharging.

[0223] In this embodiment, the remaining power percentage is further subdivided into steps within the first preset percentage range and the second preset percentage range to further reduce the first target operating power step by step. Thus, by gradually reducing the first target operating power, i.e. by progressively reducing the charging and discharging power, overcharging and over-discharging of the first target cell can be avoided. It can also eliminate voltage spikes and overcharging risks present at the traditional constant current charging or discharging ends. Based on this, it can avoid irreversible capacity loss in multiple cells in the battery management system, significantly improving the safety and lifespan of multiple cells.

[0224] Optionally, if the remaining percentage of the first target battery cell is within a first preset percentage range or a second preset percentage range, a continuous function, such as an exponential decay function, can be used to smoothly derating the first target operating power to protect the lifespan of the first target battery cell.

[0225] Based on this, in an exemplary embodiment, the formula for calculating the second target operating power is:

[0226] P_limit2= P_limit1×exp[-λ1×(SOC_now-90)]

[0227] Where P_limit2 represents the second target operating power, P_limit1 represents the first target operating power, λ1 represents the first attenuation coefficient, and SOC_now represents the remaining percentage of power.

[0228] Based on this, in an exemplary embodiment, the formula for calculating the third target operating power is:

[0229] P_limit3= P_limit1×exp[-λ2×(10-SOC_now)]

[0230] Where P_limit3 represents the third target operating power, P_limit1 represents the first target operating power, λ2 represents the second attenuation coefficient, and SOC_now represents the remaining percentage of power.

[0231] The first attenuation coefficient can be understood as the attenuation coefficient during the charging process, and the second attenuation coefficient can be understood as the attenuation coefficient during the discharging process. When the battery cell is an LFP cell, the first attenuation coefficient and the second attenuation coefficient can be 0.1~0.3.

[0232] Optionally, the operational capability table can also be dynamically generated through self-learning. Based on this, in an exemplary embodiment, the process of obtaining the above-mentioned operational capability table is as follows: when the number of charge-discharge cycles of the battery cell is less than the operation cycle threshold, the battery cell is controlled to operate at a fourth target operating power; the fourth operating power is less than the rated power of the battery cell; after the battery cell has undergone multiple charge-discharge cycles at the fourth target operating power, the maximum operating power of the battery cell in each training temperature range and each training remaining charge percentage range is recorded to obtain the operational capability table.

[0233] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0234] Based on the same inventive concept, this application also provides a battery cell power control device for implementing the battery cell power control method described above. The solution provided by this device is similar to the solution described in the above method; therefore, the specific limitations in one or more battery cell power control device embodiments provided below can be found in the limitations of the battery cell power control method described above, and will not be repeated here.

[0235] In one exemplary embodiment, such as Figure 3 As shown, a cell power control device is provided, applied in the control module of a battery management system. The battery management system is connected to multiple cells of the same model that share a common operating capacity table. The operating capacity table has preset relationships between preset surface temperatures, preset remaining charge percentages, and preset operating power of the multiple cells. The device includes: a data acquisition module 302, a determination module 304, and a control module 306, wherein:

[0236] The acquisition module 302 is used to acquire the surface temperature and remaining charge percentage of the first target battery cell at preset time intervals during the operation of the first target battery cell; the first target battery cell is one of multiple battery cells.

[0237] The determination module 304 is used to determine the preset operating power corresponding to the surface temperature and remaining charge percentage of the first target cell in the operating capacity table, so as to obtain the first target operating power of the first target cell.

[0238] The control module 306 is used to control the first target cell to operate at the first target operating power at preset time intervals.

[0239] In an exemplary embodiment, the operating capability table has a preset correspondence between preset temperature ranges, preset remaining power ranges, and preset operating power of multiple battery cells.

[0240] In an exemplary embodiment, regarding the determination of the preset operating power corresponding to the surface temperature and remaining charge percentage of the first target battery cell in the aforementioned operating capability table, to obtain the first target operating power of the first target battery cell, the determining module 304 is specifically used to determine the preset temperature range corresponding to the first target battery cell in the operating capability table based on the surface temperature of the first target battery cell; determine the preset charge range corresponding to the first target battery cell in the operating capability table based on the remaining charge percentage of the first target battery cell; and determine the preset operating power corresponding to the preset temperature range and preset remaining charge range of the first target battery cell in the operating capability table to obtain the first target operating power of the first target battery cell.

[0241] In an exemplary embodiment, in the aforementioned operating capability table, a preset operating power corresponding to a preset temperature range and a preset remaining power range of the first target battery cell is determined to obtain a first target operating power of the first target battery cell. Specifically, the determining module 304 is used to: determine the upper temperature limit and lower temperature limit of the preset temperature range corresponding to the first target battery cell in the operating capability table; determine the preset operating power corresponding to the preset temperature range and the preset remaining power range of the first target battery cell in the operating capability table; determine the previous preset operating power corresponding to the previous preset temperature range and the preset remaining power range in the operating capability table; the previous preset operating power is less than the preset operating power; and determine the first target operating power of the first target battery cell based on the surface temperature of the first target battery cell, the corresponding upper temperature limit, the corresponding lower temperature limit, the corresponding previous preset operating power, and the corresponding preset operating power.

[0242] In an exemplary embodiment, the control module 306 is further configured to measure the voltage and current changes of the first target battery cell at the instant the first target battery cell switches from the operating state to the stationary state or the reverse operating state after each complete operation of the first target battery cell; obtain the actual internal resistance value of the first target battery cell based on the voltage and current changes; determine the internal resistance growth rate based on the actual internal resistance value and the initial internal resistance value of the first target battery cell; determine the aging coefficient of the first target battery cell based on the internal resistance growth rate and the first empirical coefficient; the control module 306 is further configured to determine the preset operating power corresponding to the surface temperature and remaining charge percentage of the first target battery cell in the operating capacity table, obtain the initial target operating power of the first target battery cell; determine the first target operating power of the first target battery cell based on the initial target operating power and the aging coefficient; the first target operating power is less than the initial target operating power.

[0243] In an exemplary embodiment, the control module 306 is further configured to acquire the voltage of each of the multiple battery cells at preset time intervals; determine at least one equalizing battery cell among the multiple battery cells to participate in the equalization process based on the surface temperature of the multiple battery cells and the voltage of each battery cell; perform equalization processing on the remaining power percentage of each equalizing battery cell; and in at least one equalizing battery cell after the remaining power percentage has been equalized, the voltage difference between the maximum voltage value and the minimum voltage value is less than or equal to the voltage difference threshold.

[0244] In an exemplary embodiment, regarding the determination of at least one equalizing cell among the multiple cells for equalization processing based on the surface temperatures and voltages of the multiple cells, the control module 306 is specifically configured to: determine a second target cell with a maximum surface temperature based on the surface temperatures of the multiple cells; the second target cell is one of the multiple cells; if the maximum surface temperature of the second target cell is greater than a first temperature threshold, determine at least one cell among the multiple cells whose voltage is greater than the first voltage threshold as at least one equalizing cell; or, determine a third target cell with a minimum surface temperature based on the surface temperatures of the multiple cells; the third target cell is one of the multiple cells; if the minimum surface temperature of the third target cell is less than the second temperature threshold, determine at least one cell among the multiple cells whose voltage is greater than the second voltage threshold as at least one equalizing cell; wherein the first temperature threshold is greater than the second temperature threshold; and the first voltage threshold is greater than the second voltage threshold.

[0245] In an exemplary embodiment, the control module 306 is further configured to determine a maximum and a minimum remaining power percentage based on the remaining power percentage of multiple battery cells; when the minimum remaining power percentage is less than a first percentage threshold, the differential pressure threshold is less than a first preset differential pressure value; when the minimum remaining power percentage is greater than a second percentage threshold, the differential pressure threshold is greater than a second preset differential pressure value; the first percentage threshold is less than the second percentage threshold, and the first preset differential pressure value is less than the second preset differential pressure value.

[0246] In an exemplary embodiment, regarding controlling the first target battery cell to operate at a first target operating power at each preset time interval, the control module 306 is specifically configured to, when the remaining charge percentage of the first target battery cell is within a first preset percentage range, reduce the first target operating power based on a first limiting coefficient to control the first target battery cell to operate at a second target operating power; the first target operating power is greater than the second target operating power, and the minimum value of the first preset percentage range is greater than or equal to 90%; when the remaining charge percentage of the first target battery cell is within a second preset percentage range, reduce the target operating power based on a second limiting coefficient to control the first target battery cell to operate at a third target operating power or stop discharging; the first target operating power is greater than the third target operating power, and the maximum value of the second preset percentage range is less than or equal to 10%.

[0247] Each module in the aforementioned battery cell power control device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of a computer device in hardware form or independent of it, or stored in the memory of a computer device in software form, so that the processor can call and execute the operations corresponding to each module.

[0248] In one exemplary embodiment, a computer device is provided, which may be a server, and its internal structure diagram may be as follows: Figure 4As shown, the computer device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides the environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The database stores data related to the battery cell power control method. The I / O interfaces are used for exchanging information between the processor and external devices. The communication interface is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements a battery cell power control method.

[0249] In one exemplary embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 5 As shown, the computer device includes a processor, memory, input / output interface, communication interface, display unit, and input device. The processor, memory, and input / output interface are connected via a system bus, and the communication interface, display unit, and input device are also connected to the system bus via the input / output interface. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The input / output interface is used for exchanging information between the processor and external devices. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, mobile cellular networks, Near Field Communication (NFC), or other technologies. When the computer program is executed by the processor, it implements a battery power control method. The display unit is used to form a visually visible image and can be a display screen, projection device, or virtual reality imaging device. The display screen can be an LCD screen or an e-ink screen. The input device of the computer device can be a touch layer covering the display screen, or buttons, trackballs, or touchpads set on the casing of the computer device, or external keyboards, touchpads, or mice, etc.

[0250] Those skilled in the art will understand that Figure 4 or Figure 5The 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 to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0251] In one exemplary embodiment, a computer device is also provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above-described method embodiments.

[0252] In one exemplary embodiment, a computer-readable storage medium is provided having a computer program stored thereon that, when executed by a processor, implements the steps in the above-described method embodiments.

[0253] In one exemplary embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.

[0254] 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 can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, artificial intelligence (AI) processors, etc., and are not limited to these.

[0255] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0256] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A cell power control method, characterized in that, In a control module of a battery management system, the battery management system is connected to multiple battery cells of the same model that share a common operating capability table. The operating capability table contains preset relationships between preset surface temperatures, preset remaining charge percentages, and preset operating power for the multiple battery cells. The method includes: During the operation of the first target battery cell, the surface temperature and remaining charge percentage of the first target battery cell are collected at preset time intervals; the first target battery cell is one of the plurality of battery cells. In the operating capacity table, a preset operating power corresponding to the surface temperature and the remaining charge percentage of the first target battery cell is determined to obtain the first target operating power of the first target battery cell; The first target battery cell is controlled to operate at the first target operating power at preset time intervals.

2. The method according to claim 1, characterized in that, The operating capacity table has a preset correspondence between preset temperature ranges, preset remaining power ranges, and preset operating power of multiple battery cells. The step of determining the operating power corresponding to the surface temperature and remaining charge percentage of the first target battery cell in the operating capacity table, and obtaining the first target operating power of the first target battery cell, includes: Based on the surface temperature of the first target battery cell, a preset temperature range corresponding to the first target battery cell in the operating capability table is determined. Based on the remaining percentage of the first target battery cell, a preset battery range corresponding to the first target battery cell in the operating capability table is determined; In the operating capacity table, a preset operating power corresponding to the preset temperature range and the preset remaining power range of the first target battery cell is determined to obtain the first target operating power of the first target battery cell.

3. The method according to claim 2, characterized in that, The step of determining the preset operating power corresponding to the preset temperature range and the preset remaining power range of the first target battery cell in the operating capacity table, and obtaining the first target operating power of the first target battery cell, includes: In the operational capability table, the upper and lower temperature limits of the preset temperature range corresponding to the first target cell are determined; In the operating capability table, a preset operating power corresponding to the preset temperature range and the preset remaining power range of the first target battery cell is determined; In the operating capacity table, a previous preset operating power corresponding to the previous preset temperature range and the preset remaining power range is determined; the previous preset operating power is less than the preset operating power. Based on the surface temperature of the first target cell, the corresponding upper temperature limit, the corresponding lower temperature limit, the corresponding previous preset operating power, and the corresponding preset operating power, the first target operating power of the first target cell is determined.

4. The method according to claim 3, characterized in that, The formula for calculating the first target operating power of the first target battery cell is as follows: P_limit1=P1+(P2-P1)×(T_now-T1) / (T2-T1) Where P_limit1 represents the first target operating power, P1 represents the previous preset operating power, P2 represents the preset operating power, T_now represents the surface temperature, T1 represents the lower limit of the temperature, and T2 represents the upper limit of the temperature.

5. The method according to claim 1, characterized in that, The method further includes: After the first target cell completes each full operation, at the instant when the first target cell switches from the operating state to the stationary state or the reverse operating state, the voltage change and current change of the first target cell are measured. Based on the voltage change and the current change, the actual internal resistance value of the first target cell is obtained; The internal resistance growth rate is determined based on the actual internal resistance value and the initial internal resistance value of the first target cell. Based on the internal resistance growth rate and the first empirical coefficient, the aging coefficient of the first target cell is determined. The step of determining a preset operating power corresponding to the surface temperature and remaining charge percentage of the first target battery cell in the operating capacity table, and obtaining the first target operating power of the first target battery cell, includes: In the operating capacity table, a preset operating power corresponding to the surface temperature and remaining charge percentage of the first target cell is determined to obtain the initial target operating power of the first target cell; Based on the initial target operating power and the aging coefficient, the first target operating power of the first target cell is determined; the first target operating power is less than the initial target operating power.

6. The method according to claim 1, characterized in that, The method further includes: The voltage of each of the multiple battery cells is collected at preset time intervals; Based on the surface temperature and voltage of each of the multiple battery cells, at least one equalizing cell is identified among the multiple battery cells to participate in the equalization process. The remaining charge percentage of each of the balanced cells is balanced; in at least one of the balanced cells after the remaining charge percentage is balanced, the voltage difference between the maximum voltage value and the minimum voltage value is less than or equal to the voltage difference threshold.

7. The method according to claim 6, characterized in that, The step of determining at least one equalizing cell to participate in the equalization process from among the multiple battery cells based on the surface temperature and voltage of each battery cell includes: Based on the surface temperatures of the plurality of battery cells, a second target battery cell with the maximum surface temperature is determined; the second target battery cell is one of the plurality of battery cells. If the maximum surface temperature of the second target cell is greater than the first temperature threshold, at least one cell among the plurality of cells whose voltage is greater than the first voltage threshold is identified as at least one of the balanced cells; or... Based on the surface temperatures of the plurality of battery cells, a third target battery cell with the minimum surface temperature is determined; the third target battery cell is one of the plurality of battery cells. If the minimum surface temperature of the third target cell is less than the second temperature threshold, at least one cell among the plurality of cells whose voltage is greater than the second voltage threshold is identified as at least one of the balanced cells. Wherein, the first temperature threshold is greater than the second temperature threshold; the first voltage threshold is greater than the second voltage threshold.

8. The method according to claim 6, characterized in that, The method further includes: Based on the remaining percentage of the battery cells, determine the maximum and minimum remaining percentage of the battery cells; When the minimum remaining battery percentage is less than a first percentage threshold, the differential pressure threshold is less than a first preset differential pressure value; When the minimum remaining power percentage is greater than the second percentage threshold, the differential pressure threshold is greater than the second preset differential pressure value; the first percentage threshold is less than the second percentage threshold, and the first preset differential pressure value is less than the second preset differential pressure value.

9. The method according to claim 1, characterized in that, The step of controlling the first target battery cell to operate at the first target operating power at preset time intervals includes: When the remaining charge percentage of the first target battery cell is within a first preset percentage range, the first target operating power is reduced based on a first limiting coefficient to control the first target battery cell to operate at a second target operating power; the first target operating power is greater than the second target operating power, and the minimum value of the first preset percentage range is greater than or equal to 90%; When the remaining charge percentage of the first target cell is within the second preset percentage range, the target operating power is reduced based on the second limiting coefficient to control the first target cell to operate at the third target operating power or stop discharging; the first target operating power is greater than the third target operating power, and the maximum value of the second preset percentage range is less than or equal to 10%.

10. A cell power control device, characterized in that, In the control module of the battery management system, the battery management system is connected to multiple battery cells. The multiple battery cells are of the same model and share a common operating capacity table. The operating capacity table has a preset correspondence between the preset surface temperature, preset remaining charge percentage and preset operating power of the multiple battery cells. The device includes: The data acquisition module is used to acquire the surface temperature and remaining charge percentage of the first target battery cell at preset time intervals during the operation of the first target battery cell; the first target battery cell is one of the plurality of battery cells. The determining module is used to determine, in the operating capability table, a preset operating power corresponding to the surface temperature and the remaining charge percentage of the first target cell, to obtain the first target operating power of the first target cell; The control module is used to control the first target cell to operate at the first target operating power at preset time intervals.

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