Battery balancing control method, system, storage medium, electronic device and vehicle

Abstract

The present invention relates to the field of battery management technology, and in particular to a battery balancing control method, system, storage medium, electronic device and vehicle, the method comprising: obtaining the balancing time of each battery cell according to the balancing current and the amount of electricity to be balanced of each battery cell in a power battery pack; determining a target balancing strategy according to the BMS state of the power battery pack and the state data of the power battery pack; balancing the power battery pack based on the balancing time of each battery cell and in combination with the target balancing strategy. The target balancing strategy is determined in combination with the BMS state and the state data of the power battery pack, and the power battery pack is balanced based on the balancing time of each battery cell, so that the balancing is more accurate, and the phenomenon of misbalancing or over-balancing will not occur, and the waste of resources can be effectively avoided.

Description

Background Art

[0002] As a new energy transportation tool that is emerging, electric vehicles are showing more and more advantages. The power battery of electric vehicles is usually composed of hundreds or thousands of battery cells connected in series and parallel. Although the battery cells are strictly screened before grouping to try to maintain the consistency between the battery cells, due to objective factors such as uneven raw materials and differences in manufacturing processes, there are still inevitable subtle differences between the battery cells, such as initial SOC (battery state of charge, SOC is the abbreviation of State of Charge) and impedance differences. In addition, during use, as the charging and discharging process proceeds and the heat propagation and interaction between adjacent battery cells, the differences between the battery cells will gradually amplify and the aging speed will accelerate. Ultimately, these factors will inevitably lead to inconsistency between the battery cells, which is characterized by an increase in the attenuation of the battery SOC. Therefore, in the face of the increasingly pressing problem of power battery inconsistency, how to effectively balance the battery pack so that the deviation of the battery cells in the battery pack is kept within the expected range to extend the service life of the battery pack will be a major issue affecting the development of new energy vehicles.

[0003] Although most of the existing battery pack balancing technologies have achieved full-range balancing, they do not consider the impact of current and temperature on the internal resistance of the battery itself, and cannot effectively avoid over-balancing or mis-balancing. When over-balancing or mis-balancing occurs, the voltage difference between the batteries will increase, resulting in a decrease in the available capacity of the battery, and will also cause new balancing, resulting in a waste of resources. In summary, the research on battery pack balancing control strategies needs further in-depth research and improvement, and it is necessary to provide a battery pack balancing method that can solve the above problems. Summary of the invention

[0004] The technical problem to be solved by the present invention is to address the deficiencies in the prior art and provide a battery balancing control method, system, storage medium, electronic device and vehicle.

[0005] A technical solution of a battery balancing control method of the present invention is as follows:

[0006] According to the balancing current and the amount of electricity to be balanced of each cell in the power battery pack, the balancing time of each cell is obtained;

[0007] Determine a target balancing strategy according to the BMS state of the power battery pack and the state data of the power battery pack;

[0008] Based on the balancing time of each battery cell and in combination with the target balancing strategy, the power battery pack is balanced.

[0009] The beneficial effects of a battery balancing control method of the present invention are as follows:

[0010] The target balancing strategy is determined by combining the BMS status and the status data of the power battery pack, and the power battery pack is balanced based on the balancing time of each battery cell to make the balancing more accurate and avoid mis-balancing or over-balancing. At the same time, it can effectively avoid the waste of resources.

[0011] Based on the above solution, a battery balancing control method of the present invention can also be improved as follows.

[0012] Furthermore, the process of obtaining the amount of electricity to be balanced of each battery cell in the power battery pack includes:

[0013] When the power battery pack is in a fully charged state, a first resting time is determined according to a first current ambient temperature of the power battery pack, a first current power of each battery cell of the power battery pack after the first resting time is obtained, and a difference between the first current power of any battery cell and a first preset power threshold is determined as the power to be balanced of the battery cell, until the power to be balanced of each battery cell is obtained, wherein the first preset power threshold refers to: a minimum value of the first current power of each battery cell of the power battery pack after the first resting time;

[0014] Alternatively, when the power battery pack is in a non-fully charged state, the second standing time is determined according to the second current ambient temperature of the power battery pack, the first current voltage of any battery cell of the power battery pack after the second standing time is obtained, and the second current charge of the battery cell is obtained according to the first current voltage of the battery cell, and the difference between the second current charge of any battery cell and the second preset charge threshold is determined as the charge to be balanced of the battery cell, until the charge to be balanced of each battery cell is obtained, wherein the second preset charge threshold refers to: the minimum value of the second current charge of each battery cell of the power battery pack after the second standing time.

[0015] Further, determining a target balancing strategy according to the BMS state of the power battery pack and the state data of the power battery pack includes:

[0016] When the BMS state is the driving state, and when the state data of the power battery pack meets the first preset condition, a first balancing strategy is determined as the target balancing strategy, and the first balancing strategy is: a battery cell whose second current voltage is greater than a first preset voltage threshold is determined as a first battery cell to be balanced, at least one first battery cell to be balanced is obtained, and each first battery cell to be balanced is discharged;

[0017] When the BMS state is a power-off state, and when the state data of the power battery pack meets a second preset condition, a second balancing strategy is determined as the target balancing strategy, and the second balancing strategy is: a cell having a third current voltage greater than a second preset voltage threshold is determined as a second cell to be balanced, at least one second cell to be balanced is obtained, and each second cell to be balanced is discharged;

[0018] When the BMS state is a charging state, when the discharge duration of each discharged battery cell reaches the balancing duration of the corresponding battery cell, and when the state data of the power battery pack meets the third preset condition, the third balancing strategy is determined as the target balancing strategy, and the third balancing strategy is: determining at least one third battery cell to be balanced according to a fourth preset condition, and discharging each third battery cell to be balanced, and the fourth preset condition at least includes: the discharge duration of each discharged battery cell reaches the balancing duration of the corresponding battery cell.

[0019] Further, the fourth preset condition is: when the fourth current voltage of each battery cell is greater than the preset voltage limit, the battery cell whose fourth current voltage is greater than the third preset voltage threshold is determined as the third battery cell to be balanced; or, when the maximum voltage among all fourth current voltages is greater than the fourth preset voltage threshold, the battery cell whose fourth current voltage is greater than the fourth preset voltage threshold is determined as the third battery cell to be balanced.

[0020] Furthermore, the first preset voltage threshold V1 is: V1=V′1+V diff , the second preset voltage threshold V2 is: V2 = V′2 + V diff , the third preset voltage threshold V3 is: V3 = V′3 + ΔV, the fourth preset voltage threshold V4 is: V4 = V′4 + ΔV;

[0021] Wherein, ΔV=U+(X×ΔT+Y)×I, V′1 represents the minimum value of all second current voltages, V′2 represents the minimum value of all third current voltages, V′3 represents the minimum value of all fourth current voltages, V′4 represents the preset voltage, V diff represents the preset sampling voltage error value, ΔT represents the temperature difference between the cells, X represents the change value of the internal resistance of any cell when ΔT changes by 1°C, Y represents the internal resistance of any cell, I represents the balancing current, and U represents the preset sampling voltage error value corresponding to the balancing current of 0A.

[0022] Furthermore, it also includes:

[0023] The method further comprises: correcting the amount of electricity to be balanced of each battery cell according to the health status of the power battery pack to obtain the corrected amount of electricity to be balanced of each battery cell; and obtaining the balancing time of each battery cell according to the balancing current and the amount of electricity to be balanced of each battery cell, including:

[0024] The balancing time of each battery cell is obtained according to the balancing current and the corrected amount of electricity to be balanced of each battery cell to be balanced.

[0025] The technical solution of a battery balancing control system of the present invention is as follows:

[0026] It includes an acquisition module, a determination module and a balancing module;

[0027] The acquisition module is used to obtain the balancing time of each battery cell according to the balancing current and the amount of electricity to be balanced of each battery cell in the power battery pack;

[0028] The determination module is used to: determine a target balancing strategy according to the BMS state of the power battery pack and the state data of the power battery pack;

[0029] The balancing module is used to balance the power battery pack based on the balancing time of each battery cell and in combination with the target balancing strategy.

[0030] The beneficial effects of a battery balancing control system of the present invention are as follows:

[0031] The target balancing strategy is determined by combining the BMS status and the status data of the power battery pack, and the power battery pack is balanced based on the balancing time of each battery cell to make the balancing more accurate and avoid mis-balancing or over-balancing. At the same time, it can effectively avoid the waste of resources.

[0032] Based on the above solution, a battery balancing control system of the present invention can also be improved as follows.

[0033] Furthermore, the acquisition module is specifically used for:

[0034] When the power battery pack is in a fully charged state, a first resting time is determined according to a first current ambient temperature of the power battery pack, a first current power of each battery cell of the power battery pack after the first resting time is obtained, and a difference between the first current power of any battery cell and a first preset power threshold is determined as the power to be balanced of the battery cell, until the power to be balanced of each battery cell is obtained, wherein the first preset power threshold refers to: a minimum value of the first current power of each battery cell of the power battery pack after the first resting time;

[0035] Alternatively, when the power battery pack is in a non-fully charged state, the second standing time is determined according to the second current ambient temperature of the power battery pack, the first current voltage of any battery cell of the power battery pack after the second standing time is obtained, and the second current charge of the battery cell is obtained according to the first current voltage of the battery cell, and the difference between the second current charge of any battery cell and the second preset charge threshold is determined as the charge to be balanced of the battery cell, until the charge to be balanced of each battery cell is obtained, wherein the second preset charge threshold refers to: the minimum value of the second current charge of each battery cell of the power battery pack after the second standing time.

[0036] Furthermore, the acquisition module is specifically used for:

[0037] When the BMS state is the driving state, and when the state data of the power battery pack meets the first preset condition, a first balancing strategy is determined as the target balancing strategy, and the first balancing strategy is: a battery cell whose second current voltage is greater than a first preset voltage threshold is determined as a first battery cell to be balanced, at least one first battery cell to be balanced is obtained, and each first battery cell to be balanced is discharged;

[0038] When the BMS state is a power-off state, and when the state data of the power battery pack meets a second preset condition, a second balancing strategy is determined as the target balancing strategy, and the second balancing strategy is: a cell having a third current voltage greater than a second preset voltage threshold is determined as a second cell to be balanced, at least one second cell to be balanced is obtained, and each second cell to be balanced is discharged;

[0039] When the BMS state is a charging state, when the discharge time of each discharged battery cell reaches the balancing time of the corresponding battery cell, and when the state data of the power battery pack meets the third preset condition, a third balancing strategy is determined as the target balancing strategy, and the third balancing strategy is: determining at least one third battery cell to be balanced according to the fourth preset condition, and discharging each third battery cell to be balanced;

[0040] Further, the fourth preset condition is: when the fourth current voltage of each battery cell is greater than the preset voltage limit, the battery cell whose fourth current voltage is greater than the third preset voltage threshold is determined as the third battery cell to be balanced; or, when the maximum voltage among all fourth current voltages is greater than the fourth preset voltage threshold, the battery cell whose fourth current voltage is greater than the fourth preset voltage threshold is determined as the third battery cell to be balanced.

[0041] Furthermore, the first preset voltage threshold V1 is: V1=V′1+V diff , the second preset voltage threshold V2 is: V2 = V′2 + V diff, the third preset voltage threshold V3 is: V3 = V′3 + ΔV, the fourth preset voltage threshold V4 is: V4 = V′4 + ΔV;

[0042] Wherein, ΔV=U+(X×ΔT+Y)×I, V′1 represents the minimum value of all second current voltages, V′2 represents the minimum value of all third current voltages, V′3 represents the minimum value of all fourth current voltages, V′4 represents the preset voltage, V diff represents the preset sampling voltage error value, ΔT represents the temperature difference between the cells, X represents the change value of the internal resistance of any cell when ΔT changes by 1°C, Y represents the internal resistance of any cell, I represents the balancing current, and U represents the preset sampling voltage error value corresponding to the balancing current of 0A.

[0043] Furthermore, a correction module is included, wherein the correction module is used to:

[0044] Correcting the amount of electricity to be balanced of each battery cell according to the health status of the power battery pack to obtain a corrected amount of electricity to be balanced of each battery cell to be balanced;

[0045] The process of the acquisition module obtaining the balancing time of each battery cell is as follows:

[0046] The balancing time of each battery cell is obtained according to the balancing current and the corrected amount of electricity to be balanced of each battery cell to be balanced.

[0047] A storage medium of the present invention stores instructions, and when a computer reads the instructions, the computer executes any one of the above-mentioned battery balancing control methods.

[0048] An electronic device of the present invention comprises a processor and the above-mentioned storage medium, wherein the processor executes instructions in the storage medium.

[0049] A vehicle of the present invention comprises the above-mentioned electronic device. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is a flow chart of a battery balancing control method according to an embodiment of the present invention;

[0051] Figure 2 The second flowchart of a battery balancing control method according to an embodiment of the present invention;

[0052] Figure 3 It is the cell charging voltage curve;

[0053] Figure 4 The figure is a schematic diagram of the structure of a battery balancing control system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0054] like Figure 1 As shown, a battery balancing control method according to an embodiment of the present invention includes the following steps:

[0055] S1. Obtaining the balancing time of each battery cell according to the balancing current and the amount of electricity to be balanced of each battery cell in the power battery pack;

[0056] S2. Determine a target balancing strategy according to the BMS status of the power battery pack and the status data of the power battery pack;

[0057] S3. Based on the balancing time of each battery cell and combined with the target balancing strategy, the power battery pack is balanced.

[0058] Optionally, in the above technical solution, in S1, obtaining the balancing time of each battery cell in the power battery pack includes:

[0059] S10, obtaining the amount of power to be balanced of each cell in the power battery pack, specifically including the following two methods:

[0060] 1) When the power battery pack is in a fully charged state, a first resting time is determined according to a first current ambient temperature of the power battery pack, a first current power of each battery cell of the power battery pack after the first resting time is obtained, and a difference between the first current power of any battery cell and a first preset power threshold is determined as the power to be balanced of the battery cell, until the power to be balanced of each battery cell is obtained, wherein the first preset power threshold refers to: the minimum value of the first current power of each battery cell of the power battery pack after the first resting time, specifically:

[0061] For example, when the power battery pack is in a fully charged state, when the first current ambient temperature is ≥15°C, the first standing time is 1 hour; when the first current ambient temperature is <15°C, the first standing time is 2 hours. After the power battery pack is standing for the first standing time, a state of charge-open circuit voltage table lookup is performed on each battery cell. The state of charge-open circuit voltage table lookup is: a fitting relationship curve between the open circuit voltage and the state of charge of the battery cell, obtained by fitting multiple groups of open circuit voltages and states of charge. After a state of charge-open circuit voltage table lookup is performed on each battery cell, the state of charge value of each battery cell is obtained. The state of charge value is multiplied by the rated capacity of each battery cell to obtain the first current power of each battery cell, and the difference between the first current power of any battery cell and the first preset power threshold is determined as the power to be balanced of the battery cell, until the power to be balanced of each battery cell is obtained, wherein the first preset power threshold refers to: the minimum value of the first current power of each battery cell of the power battery pack after the first standing time.

[0062] Among them, the amount of electricity to be balanced of the i-th battery cell ΔC is obtained i The implementation method is: ΔCi =(Δc i -Δc min )×CAP,Δc i Indicates the state of charge value of the i-th battery cell, Δc min represents the minimum value of the state of charge of each cell of the power battery pack after the first resting time, CAP represents the rated capacity of the i-th cell, Δc i ×CAP is the first current capacity of the i-th battery cell, Δc min ×CAP is the minimum value of the first current power of each cell of the power battery pack after the first rest period.

[0063] 2) When the power battery pack is not fully charged, determine the second resting time according to the second current ambient temperature of the power battery pack, obtain the first current voltage of any cell of the power battery pack after the second resting time, and obtain the second current charge of the cell according to the first current voltage of the cell, and determine the difference between the second current charge of any cell and the second preset charge threshold as the charge to be balanced of the cell, until the charge to be balanced of each cell is obtained, wherein the second preset charge threshold refers to: the minimum value of the second current charge of each cell of the power battery pack after the second resting time. Specifically:

[0064] When the power battery pack rarely has a chance to be fully charged and cannot reach a fully charged state, the rated voltage of the power battery pack cannot be obtained. Then:

[0065] The second resting time is determined according to the second current ambient temperature of the power battery pack. For example, when the power battery pack is in a fully charged state, when the second current ambient temperature is ≥15°C, the second resting time is 1 hour, and when the second current ambient temperature is <15°C, the second resting time is 2 hours. After the power battery pack is rested for the second resting time, the charging dynamic voltage table is queried using the current average temperature, the first current voltage of each battery cell is queried, and the state of charge-open circuit voltage table is looked up according to the first current voltage of each battery cell to obtain the state of charge value of each battery cell. The state of charge value is multiplied by the rated capacity of each battery cell to obtain the second current power of each battery cell, and the difference between the second current power of any battery cell and the second preset power threshold is determined as the power to be balanced of the battery cell, until the power to be balanced of each battery cell is obtained, wherein the second preset power threshold refers to: the minimum value of the second current power of each battery cell of the power battery pack after the second resting time.

[0066] S11, according to the balancing current and the amount of electricity to be balanced of each battery cell, obtain the balancing time of each battery cell. Specifically:

[0067] Then use the first formula to get the equilibrium time of each battery cell. The first formula is: T i=ΔC i / I, where T i represents the balancing time of the ith cell, ΔC i represents the amount of electricity to be balanced in the ith cell, and I represents the balancing current.

[0068] Optionally, in the above technical solution, it also includes:

[0069] S12, correcting the amount of electricity to be balanced of each battery cell according to the health status of the power battery pack to obtain the corrected amount of electricity to be balanced of each battery cell to be balanced, specifically:

[0070] The second formula is used to obtain the corrected amount of power to be balanced for each battery cell to be balanced. The second formula is: ΔC′ i =ΔC i ×CAP×SOH, where ΔC′ i It represents the corrected power of the ith battery cell to be balanced, CAP represents the rated capacity of the ith battery cell, and SOH represents the health status of the power battery pack.

[0071] Then, in S11, the balancing time of each battery cell is obtained according to the balancing current and the amount of electricity to be balanced of each battery cell, including:

[0072] S110, obtaining the balancing time of each battery cell according to the balancing current and the corrected balancing power of each battery cell to be balanced, specifically:

[0073] The third formula is used to obtain the equilibrium time of each battery cell. The third formula is: T i =ΔC′ i / I.

[0074] Optionally, in the above technical solution, in S2, determining a target balancing strategy according to the BMS state and the state data of the power battery pack includes:

[0075] S20, when the BMS state is the driving state, and when the state data of the power battery pack meets the first preset condition, the first balancing strategy is determined as the target balancing strategy; specifically:

[0076] 1) The first preset condition is: the power battery pack communicates normally, the signal is valid and there is no fault, the voltage difference between the highest voltage and the lowest voltage of all the cells is within a preset range such as 200mV, 250mV, and the preset range can also be set according to actual conditions, and the temperature difference between the highest temperature and the lowest temperature of all the cells is within a preset temperature difference range such as 10°C or 15°C, and can also be set according to actual conditions. The first preset condition can also be adjusted according to actual conditions;

[0077] 2) The first balancing strategy is: determining the battery cell whose second current voltage is greater than the first preset voltage threshold as the first battery cell to be balanced, obtaining at least one first battery cell to be balanced, and discharging each first battery cell to be balanced;

[0078] Among them, the driving status indicates that the vehicle equipped with the power battery pack is driving.

[0079] When the first preset condition is not met or the BMS state is not the driving state, stop using the first balancing strategy for balancing;

[0080] S21, when the BMS state is the power-off state, and when the state data of the power battery pack meets the second preset condition, the second balancing strategy is determined as the target balancing strategy. Specifically:

[0081] 1) The second preset condition is: the power battery pack communicates normally, the signal is valid and has no faults, the voltage value and SOC value are within the normal range, and the voltage difference between the highest voltage and the lowest voltage of all cells is within the preset range such as 200mV and 250mV. The second preset condition can also be adjusted according to actual conditions;

[0082] 2) The second balancing strategy is: determining the battery cell whose third current voltage is greater than the second preset voltage threshold as the second battery cell to be balanced, obtaining at least one second battery cell to be balanced, and discharging each second battery cell to be balanced;

[0083] Among them, the power-off state means that the key switch of the vehicle installed with the power battery pack is in the off state and the vehicle is not driving.

[0084] S22, when the BMS state is the charging state, when the discharge time of each discharged battery cell reaches the balancing time of the corresponding battery cell, and when the state data of the power battery pack meets the third preset condition, the third balancing strategy is determined as the target balancing strategy, and the discharge time of each discharged battery cell reaches the balancing time of the corresponding battery cell, which means that the remaining balancing time of all battery cells is 0, specifically:

[0085] 1) The third preset condition is: the power battery pack communication is normal, the signal is valid and there is no fault, the temperature value meets the requirements, the voltage difference between the highest and lowest voltages of all cells is within 200mv, and the charging current is small during charging, such as the charging current is less than 1A or 2A, etc. The third preset condition can also be adjusted according to actual conditions;

[0086] 2) The third balancing strategy is: determine at least one third battery cell to be balanced according to the fourth preset condition, and discharge each third battery cell to be balanced.

[0087] Among them, the fourth preset condition is: when the fourth current voltage of each battery cell is greater than the preset voltage limit, the battery cell whose fourth current voltage is greater than the third preset voltage threshold is determined as the third battery cell to be balanced, or, when the maximum voltage among all fourth current voltages is greater than the fourth preset voltage threshold, the battery cell whose fourth current voltage is greater than the fourth preset voltage threshold is determined as the third battery cell to be balanced.

[0088] In S3, the power battery pack is balanced, including:

[0089] The power battery pack is balanced using the first balancing strategy, the second balancing strategy or the third balancing strategy. Specifically including:

[0090] S30, balancing the power battery pack by the first balancing strategy and / or the second balancing strategy, and when balancing the power battery pack by the first balancing strategy and / or the second balancing strategy, if the discharge time of each discharged battery cell reaches the balancing time of the corresponding battery cell, then stop discharging. Specifically:

[0091] S300, when the BMS state is the driving state, and when the state data of the power battery pack meets the first preset condition, the power battery pack is balanced by the first balancing strategy, the remaining balancing time of each battery cell is updated and stored, and when the first preset condition is not met or the BMS state is not the driving state, the first balancing strategy is stopped for balancing;

[0092] S301, when the BMS state is the power-off state, and when the state data of the power battery pack meets the second preset condition, the power battery pack is balanced by the second balancing strategy, the remaining balancing time of each battery cell is updated and stored, and when the second preset condition is not met or the BMS state is not the driving state, the second balancing strategy is stopped for balancing;

[0093] S300 to S301 are repeatedly executed until the discharge time of each discharged battery cell reaches the balancing time of the corresponding battery cell, that is, when the remaining balancing time of each discharged battery cell is 0, the discharge is stopped, and the first balancing strategy and the second balancing strategy are stopped.

[0094] S302: When the BMS state is the charging state, when the discharge time of each discharged battery cell reaches the balancing time of the corresponding battery cell, and when the state data of the power battery pack meets the third preset condition, the power battery pack is balanced using the third balancing strategy.

[0095] Optionally, in the above technical solution, the first preset voltage threshold V1 is: V1=V′1+V diff , the second preset voltage threshold V2 is: V2 = V′2 + V diff, the third preset voltage threshold V3 is: V3 = V′3 + ΔV, and the fourth preset voltage threshold V4 is: V4 = V′4 + ΔV;

[0096] Wherein, ΔV=U+(X×ΔT+Y)×I, V′1 represents the minimum value of all second current voltages, V′2 represents the minimum value of all third current voltages, V′3 represents the minimum value of all fourth current voltages, V′4 represents the preset voltage, V diff represents the preset sampling voltage error value, ΔT represents the temperature difference between the cells, X represents the change value of the internal resistance of any cell when ΔT changes by 1°C, Y represents the internal resistance of any cell, I represents the balancing current, and U represents the preset sampling voltage error value corresponding to the balancing current of 0A. The preset voltage V′4 may be equal to the preset voltage limit value, for example, 4100mV.

[0097] A battery balancing control method of the present application is described below through an embodiment, assuming that the power battery pack is in a fully charged state. Figure 2 As shown, specifically:

[0098] S100, calculate the amount of electricity to be balanced for each battery cell:

[0099] Since the power battery pack is in a fully charged state, a first resting time is determined according to a first current ambient temperature of the power battery pack, a first current power of each battery cell of the power battery pack after the first resting time is obtained, and a difference between the first current power of any battery cell and a first preset power threshold is determined as the power to be balanced of the battery cell, until the power to be balanced of each battery cell is obtained, wherein the first preset power threshold refers to: the minimum value of the first current power of each battery cell of the power battery pack after the first resting time; specifically:

[0100] When the first current ambient temperature is ≥15°C, the first standing time is 1 hour; when the first current ambient temperature is <15°C, the first standing time is 2 hours. After the power battery pack has been standing for the first standing time, a state of charge-open circuit voltage table lookup is performed on each battery cell. After a state of charge-open circuit voltage table lookup is performed on each battery cell, a state of charge value of each battery cell is obtained, and the state of charge value is multiplied by the rated capacity of each battery cell to obtain the first current power of each battery cell, and the difference between the first current power of any battery cell and the first preset power threshold is determined as the power to be balanced of the battery cell, until the power to be balanced of each battery cell is obtained.

[0101] S101, correcting the amount of electricity to be balanced for each battery cell:

[0102] According to the health status of the power battery pack, the amount of electricity to be balanced of each battery cell is corrected to obtain the corrected amount of electricity to be balanced of each battery cell to be balanced. Specifically, the corrected amount of electricity to be balanced of each battery cell to be balanced is obtained by using the second formula. The second formula is: ΔC′ i =ΔC i ×CAP×SOH, where ΔC′ i It represents the corrected power of the ith battery cell to be balanced, CAP represents the rated capacity of the ith battery cell, and SOH represents the health status of the power battery pack.

[0103] S103, calculating the balancing time of each battery cell:

[0104] According to the balancing current and the corrected amount of electricity to be balanced of each battery cell to be balanced, the balancing time of each battery cell is obtained. Specifically, the balancing time of each battery cell is obtained by using the third formula. The third formula is: T i =ΔC′ i / I.

[0105] For example, the current ambient temperature is 35°C, the power battery pack is a 50Ah ternary lithium battery with 3 parallel and 96 series, the balancing current is 55mA, the SOH is 100%, the SOC upper window of the power battery pack is 95%, and the corresponding charging cut-off voltage is 4.23V. At this time, the power battery pack is considered to be in a fully charged state, then:

[0106] For example, the voltage of the first battery cell is 4.23V, and the corresponding first current power is 95%, the voltage of the second battery cell is 4.23V, and the corresponding first current power is 95%, ..., the voltage of the 96th battery cell is 4.215V, and the corresponding first current power is 94%, then the first preset power threshold is 94%, according to the second formula: ΔC′ i =ΔC i ×CAP×SOH to obtain the corrected capacity of each battery cell to be balanced, where the rated capacity of each battery cell is 50Ah, SOH=100%, and the third formula is used: T i =ΔC′ i / I Calculate the balancing time of each battery cell, for example:

[0107] The corrected amount of power to be balanced for the 96th cell is: (95%-94%)×50Ah×100%=0.05Ah, and the balancing time is: This results in a balanced duration for each cell.

[0108] S103, determine the BMS state: determine whether the BMS state is driving state, power-off state or charging state, then:

[0109] 1) When the BMS state is driving state, execute S1030;

[0110] 2) When the BMS is in the power-off state, execute S1031;

[0111] 3) When the BMS state is in the charging state, and when the discharge time of each discharged battery cell reaches the balance time of the corresponding battery cell, execute S1032;

[0112] S1030, determining whether the status data of the power battery pack meets the first preset condition, if so, executing S10300;

[0113] Among them, the first preset condition is: the power battery pack communicates normally, the signal is valid and there is no fault, the voltage difference between the highest voltage and the lowest voltage of the battery cell in all the battery cells is within a preset range such as 200mV, 250mV, and the preset range can also be set according to actual conditions, and the temperature difference between the highest temperature and the lowest temperature of the battery cell in all the battery cells is within a preset temperature difference range such as 10°C or 15°C, which can also be set according to actual conditions, and the first preset condition can also be adjusted according to actual conditions;

[0114] S1031, determining whether the status data of the power battery pack meets a second preset condition, if so, executing S10310;

[0115] Among them, the second preset condition is: the power battery pack communication is normal, the signal is valid and there is no fault, the voltage value and SOC value are within the normal range, and the voltage difference between the highest voltage and the lowest voltage of the battery cell in all the battery cells is within the preset range such as 200mV, 250mV. The second preset condition can also be adjusted according to actual conditions;

[0116] S1032, determining whether the state data of the power battery pack meets the third preset condition, and if so, executing S10320;

[0117] Among them, the third preset condition is: the power battery pack communication is normal, the signal is valid and there is no fault, the temperature value meets the requirements, the voltage difference between the highest voltage and the lowest voltage of all cells is within 200mv, and the charging current is small during charging, such as the charging current is less than 1A or 2A, etc. The third preset condition can also be adjusted according to actual conditions;

[0118] S10300: Start driving balancing, and perform discharge balancing on each first battery cell to be balanced, that is, perform balancing using a first balancing strategy, specifically:

[0119] When the BMS state is the driving state, and when the state data of the power battery pack meets the first preset condition, the first balancing strategy is determined as the target balancing strategy, and the power battery pack is balanced by the first balancing strategy. That is to say, the process of balancing the power battery pack by the first balancing strategy is driving balancing, which is specifically:

[0120] Determine the battery cell whose second current voltage is greater than the first preset voltage threshold as the first battery cell to be balanced, obtain at least one first battery cell to be balanced, discharge each first battery cell to be balanced, update the remaining balancing time of each battery cell, and store the time, and stop using driving balancing when the first preset condition is not met or the BMS state is not the driving state;

[0121] The first preset voltage threshold V1 is: V1 = V′1 + V diff , V′1 represents the minimum value of all second current voltages, V diff Indicates the preset sampling voltage error value.

[0122] S10310: Enable low power consumption balancing, and perform discharge balancing on each second battery cell to be balanced, that is, perform balancing through the second balancing strategy, specifically:

[0123] When the BMS state is the power-off state, and when the state data of the power battery pack meets the second preset condition, the second balancing strategy is determined as the target balancing strategy, and the power battery pack is balanced by the second balancing strategy. That is to say, the process of balancing the power battery pack by the second balancing strategy is low power consumption balancing, specifically:

[0124] Determine the battery cell whose third current voltage is greater than the second preset voltage threshold as the second battery cell to be balanced, obtain at least one second battery cell to be balanced, and discharge each second battery cell to be balanced. Update the remaining balance time of each battery cell and store it. When the second preset condition is not met or the BMS state is not the driving state, stop low-power balancing;

[0125] The second preset voltage threshold V2 is: V2 = V′2 + V diff , where V′2 represents the minimum value among all third current voltages, V diff Indicates the preset sampling voltage error value.

[0126] When low power balancing is turned on, the "timed wake-up detection" step is also performed. The timed wake-up detection is:

[0127] A scheduled autonomous wake-up diagnosis is performed every 5 minutes. Considering the heat, temperature rise, and undervoltage during balancing, it is determined whether the conditions for stopping the low-power balancing strategy have been met. If the diagnosis shows that the balancing stop conditions are met, the balancing process is stopped and the stored balancing remaining time is updated. If the diagnosis shows that the balancing stop conditions are not met, the balancing process is continued until the balancing remaining time is 0, and the balancing process and autonomous wake-up diagnosis are stopped. During the autonomous wake-up diagnosis, if it is determined that the normal power is <11.8V, all balancing is stopped and autonomous wake-up is not performed after hibernation. In order to minimize power consumption during autonomous wake-up, the hibernation after autonomous wake-up diagnosis is not stored, and message sending is stopped.

[0128] S10300 to S10310 may be repeatedly executed until the discharge time of each discharged battery cell reaches the balancing time of the corresponding battery cell, that is, when the remaining balancing time of each discharged battery cell is 0, the discharge is stopped, and the first balancing strategy and the second balancing strategy are stopped.

[0129] S10320: Turn on charge balancing and discharge each third battery cell to be balanced, that is, balance through the third balancing strategy, wherein, when the fourth current voltage of each battery cell is greater than the preset voltage limit, the battery cell whose fourth current voltage is greater than the third preset voltage threshold is determined as the third battery cell to be balanced, or, when the maximum voltage among all fourth current voltages is greater than the fourth preset voltage threshold, the battery cell whose fourth current voltage is greater than the fourth preset voltage threshold is determined as the third battery cell to be balanced.

[0130] Among them, the third preset voltage threshold V3 is: V3=V′3+ΔV, ΔV=U+(X×ΔT+Y)×I, V′3 represents the minimum value of all fourth current voltages, ΔT represents the temperature difference between the battery cells, X represents: when ΔT changes by 1°C, the change value of the internal resistance corresponding to any battery cell, Y represents the internal resistance of any battery cell, I represents the balancing current, and U represents: the preset sampling voltage error value corresponding to the balancing current of 0A.

[0131] Among them, the fourth preset voltage threshold V4 is: V4=V′4+ΔV, ΔV=U+(X+ΔT+Y)×I, V′4 represents the preset voltage, ΔT represents the temperature difference between the cells, X represents: the change value of the internal resistance corresponding to any cell when ΔT changes by 1°C, Y represents the internal resistance of any cell, I represents the balancing current, and U represents: the preset sampling voltage error value corresponding to the balancing current of 0A. Specifically:

[0132] For example, the preset voltage limit may be set to 4100 mV. When the voltage of each battery cell is greater than 4100 mV, the battery cell with the fourth current voltage>(V′3+ΔV) is selected for discharge balancing. That is, the battery cell with the fourth current voltage greater than the third preset voltage threshold is determined as the third battery cell to be balanced, and discharge balancing is performed.

[0133] Alternatively, when the maximum voltage among all fourth current voltages is greater than the fourth preset voltage threshold V4, the battery cell whose fourth current voltage is greater than the fourth preset voltage threshold is determined as the third battery cell to be balanced. Taking the preset voltage V′4=4100mV as an example, that is, when the maximum voltage is greater than (4100mV+ΔV), the battery cell whose fourth current voltage>(4100mV+ΔV) is selected for discharge balancing.

[0134] For example, in this embodiment, when the SOC is 95%, the first ambient temperature is 35°C, the balancing current is 18A, and the preset sampling voltage error value V diff =10mV, the static voltage value of the first battery cell obtained by OCV-SOC lookup is 4231mV, the static voltage value of the second battery cell obtained by OCV-SOC lookup is 4200mV, the fourth current voltage of the third battery cell is 4189mV, and the static voltage values ​​of the fourth to the 96th battery cells are all 4231mV. It can be seen that the lowest voltage among the fourth current voltages of all the battery cells is 4189mV. The fourth current voltage of the battery cells is greater than the preset voltage limit, that is, the fourth current voltage of all the battery cells is greater than 4100mV, satisfying the above "when the fourth current voltage of each battery cell is greater than the preset voltage limit, the battery cell with the fourth current voltage greater than the third preset voltage threshold is determined as the third battery cell to be balanced". Therefore, the battery cell with the fourth current voltage > (V′3+ΔV) is selected for discharge balancing, that is, the third battery cell to be balanced is discharged and balanced, and the charge balancing is exited when there is a 3mV margin when balanced.

[0135] When the influence of current and temperature is not considered, ΔV is equal to the preset sampling voltage error value U corresponding to the balancing current of 0A, and ΔV=ΔV1=U=10mV is obtained;

[0136] When the influence of current is considered, by querying the internal resistance table (SOC=95%, T=25℃), the ohmic internal resistance value is 0.1mΩ, that is, Y=0.1mΩ, and the voltage difference generated by the ohmic internal resistance itself is ΔV2=Y×I=0.1mΩ×18=1.8mV; when considering the influence of temperature, the highest temperature of all battery cells is 37℃, the lowest temperature of all battery cells is 32℃, the temperature difference is 5℃, that is, ΔT=5℃, and the temperature of the power battery pack is greater than 20℃. When the temperature changes by 1℃, the internal resistance value X (mΩ) corresponding to each battery cell is 0.02mΩ, that is, X=0.02mΩ, so the internal resistance pressure difference caused by the temperature difference is ΔV3=X×ΔT×I=(0.02×5)mΩ×18A=1.8mV.

[0137] During the charging stage, without considering the influence of current and temperature, ΔV=ΔV1=U=10mV, and the battery cell with the fourth current voltage>4189mV+10mV=4199mV is selected for balancing. The balancing is exited when there is a 3mV margin with the lowest voltage among all the fourth current voltages. The 1st battery cell, the 2nd battery cell, and the 4th battery cell to the 96th battery cell all meet the selection conditions for the balanced battery cells. Among them, the balancing is exited when the fourth current voltage of the second battery cell is balanced from 4200mV to 4192mV.

[0138] When the influence of current and temperature is considered, ΔV=U+(X×ΔT+Y)×I=13.6mV, and the cell with the fourth current voltage>4189mV+13.6mV=4202.6mV is selected for balancing. The second cell is 4200mV and does not meet the selection condition of the balancing cell, so balancing is not turned on.

[0139] During the charging process, the cell voltage is polarized, that is, it is affected by current and temperature. When the battery is fully charged and left to stand, the power supply is removed and the current becomes 0A. The voltage difference caused by the current and temperature difference of the internal resistance disappears, and the voltage will slowly fall back. In the example where the influence of current and temperature is not considered, that is, when ΔV=ΔV1=U=10mV, the fourth current voltage of the second cell after equalization will change from 4192mV to 4192mV-3.6mV=4188.4mV under the influence of cell polarization, that is, the drop value minus the voltage, which is lower than the lowest voltage, that is, 4189mV of the third cell, resulting in over-balancing of the second cell and mis-balancing of the second cell. In addition, since the second cell has become the lowest voltage at this time, it will be judged again with the second cell as the lowest voltage, causing a new charge equalization to be started, resulting in a waste of resources. In the present application, when the influence of current and temperature is considered, the second battery cell does not meet the balancing start condition and will not be balanced, which will not cause over-balancing and mis-balancing phenomena.

[0140] A battery balancing control method of the present invention is a full-operating condition battery balancing control strategy method based on full-charge cutoff difference to achieve balancing in the full operating condition range through driving balancing strategy, low-power balancing strategy and charging balancing strategy. The balancing time is calculated based on the full-charge cutoff difference, the timing is selected to be the fully charged state of the battery, and the state of charge-open circuit voltage table is used to obtain the first current power of each battery cell of the power battery pack after the first static time, or the second current power of each battery cell of the power battery pack after the second static time is obtained to calculate the balancing time.

[0141] When the battery is in a state where it cannot reach a full charge state but is about to be fully charged, the charging dynamic voltage table is queried through the average temperature, and the voltage value queried through the charging dynamic voltage table is used to perform a state of charge-open circuit voltage table lookup to obtain the second current power of each cell of the power battery pack after the second static time, and then the remaining time for balancing is calculated, and all cells are in a state as close as possible based on the full charge cut-off difference, and aligned to the full charge state, so as to achieve better efficiency and effect of balancing;

[0142] The low-power balancing strategy determines whether to stop the low-power balancing strategy through autonomous wake-up diagnosis, and reduces the power consumption of the balancing process by not performing NvM storage and stopping message sending after autonomous wake-up.

[0143] When the SOC exceeds 90% during the charging phase, the charging equalization strategy considers the influence of current and temperature and selects equalization cells for equalization. When the battery is fully charged and the power is removed, the voltage will drop back to the open circuit voltage due to polarization. Due to the existence of ohmic polarization, according to Ohm's law, when current flows through the battery, there will be a potential drop. The reduced voltage U1 = internal resistance × current. The reduced voltage U1 is the voltage drop caused by ohmic polarization. Figure 3 shown.

[0144] Therefore, it is necessary to exclude the influence of the cell's own internal resistance after the balancing current is removed. Because the temperature is different, the internal resistance is also different. It is necessary to exclude the voltage difference caused by temperature change. Therefore, ΔV is introduced when selecting the balancing cell. Specifically:

[0145] The internal resistance value Y (mΩ) found by the internal resistance meter multiplied by the balancing current I (A) is the pressure difference generated by the ohmic internal resistance. Y×I excludes the pressure difference of the ohmic internal resistance itself after the battery is fully charged and the power is removed. When considering the influence of temperature on the internal resistance, the internal resistance also has corresponding differences due to different temperatures. The internal resistance value X (mΩ) corresponding to the battery cell when the temperature changes by 1°C multiplied by the temperature difference ΔT (°C) and the balancing current I (A) is the pressure difference generated by the internal resistance when the temperature difference is ΔT. Add Y×I and X×ΔT×I, and then add them to the reserved sampling error U, that is, add them to the preset sampling voltage error value U corresponding to the balancing current of 0A, and you will get the voltage correction value ΔV (mV). The introduction of the voltage correction value ΔV (mV) makes the selection of balancing cells more comprehensive and reasonable, eliminates the influence of current and temperature changes, makes balancing more accurate, and does not cause false balancing or over-balancing.

[0146] In the prior art, specifically:

[0147] 1) The first comparative invention patent (publication number: CN108110336A, subject name: battery pack balancing control method, device and apparatus) uses the voltage value of the battery cell in the battery pack in a static state and the minimum voltage value of the battery cell in the battery pack to determine the battery cell to be balanced in the battery pack;

[0148] 2) In the second comparative invention patent (publication number: CN107947268A, subject name: battery pack balancing method, device and equipment), the battery cell to be balanced is determined by comparing the voltage value and voltage threshold of the battery cell to be processed, and the voltage difference and voltage difference threshold, wherein the voltage threshold is selected according to the battery cell temperature;

[0149] In the present invention, the influence of current and temperature is considered when selecting the balancing cell. After the voltage correction value ΔV is introduced, the influence of current and temperature changes is eliminated, making the balancing more accurate, and preventing the phenomenon of mis-balancing or over-balancing. At the same time, it can effectively avoid the waste of resources.

[0150] In the above embodiments, although the steps are numbered S1, S2, etc., these are only specific embodiments given in the present application. Those skilled in the art may adjust the execution order of S1, S2, etc. according to actual conditions, which is also within the scope of protection of the present invention. It can be understood that in some embodiments, some or all of the above embodiments may be included.

[0151] like Figure 4 As shown, a battery balancing control system 200 according to an embodiment of the present invention includes an acquisition module 210, a determination module 220 and a balancing module 230;

[0152] The acquisition module 210 is used to obtain the balancing time of each battery cell according to the balancing current and the amount of electricity to be balanced of each battery cell in the power battery pack;

[0153] The determination module 220 is used to: determine a target balancing strategy according to the BMS status of the power battery pack and the status data of the power battery pack;

[0154] The balancing module 230 is used to balance the power battery pack based on the balancing time of each battery cell and in combination with a target balancing strategy.

[0155] The target balancing strategy is determined by combining the BMS status and the status data of the power battery pack, and the power battery pack is balanced based on the balancing time of each battery cell to make the balancing more accurate and avoid mis-balancing or over-balancing. At the same time, it can effectively avoid the waste of resources.

[0156] Optionally, in the above technical solution, the acquisition module 210 is specifically used for:

[0157] When the power battery pack is in a fully charged state, a first resting time is determined according to a first current ambient temperature of the power battery pack, a first current power of each battery cell of the power battery pack after the first resting time is obtained, and a difference between the first current power of any battery cell and a first preset power threshold is determined as the power to be balanced of the battery cell, until the power to be balanced of each battery cell is obtained, wherein the first preset power threshold refers to: the minimum value of the first current power of each battery cell of the power battery pack after the first resting time;

[0158] Alternatively, when the power battery pack is in a non-fully charged state, the second standing time is determined according to the second current ambient temperature of the power battery pack, the first current voltage of any battery cell of the power battery pack after the second standing time is obtained, and the second current charge of the battery cell is obtained according to the first current voltage of the battery cell, and the difference between the second current charge of any battery cell and the second preset charge threshold is determined as the charge to be balanced of the battery cell, until the charge to be balanced of each battery cell is obtained, wherein the second preset charge threshold refers to: the minimum value of the second current charge of each battery cell of the power battery pack after the second standing time.

[0159] Optionally, in the above technical solution, the determination module 220 is specifically used for:

[0160] When the BMS state is the driving state, and when the state data of the power battery pack meets the first preset condition, the first balancing strategy is determined as the target balancing strategy, and the first balancing strategy is: a battery cell whose second current voltage is greater than the first preset voltage threshold is determined as a first battery cell to be balanced, at least one first battery cell to be balanced is obtained, and each first battery cell to be balanced is discharged;

[0161] When the BMS state is in the power-off state, and when the state data of the power battery pack meets the second preset condition, the second balancing strategy is determined as the target balancing strategy, and the second balancing strategy is: a cell whose third current voltage is greater than the second preset voltage threshold is determined as a second cell to be balanced, at least one second cell to be balanced is obtained, and each second cell to be balanced is discharged;

[0162] When the BMS state is in the charging state, when the discharge time of each discharged battery cell reaches the balancing time of the corresponding battery cell, and when the state data of the power battery pack meets the third preset condition, the third balancing strategy is determined as the target balancing strategy, and the third balancing strategy is: determining at least one third battery cell to be balanced according to the fourth preset condition, and discharging each third battery cell to be balanced;

[0163] The equalization module 230 is specifically used for:

[0164] The power battery pack is balanced using the first balancing strategy, the second balancing strategy or the third balancing strategy.

[0165] Optionally, in the above technical solution, the fourth preset condition is: when the fourth current voltage of each battery cell is greater than the preset voltage limit, the battery cell whose fourth current voltage is greater than the third preset voltage threshold is determined as the third battery cell to be balanced; or, when the maximum voltage among all fourth current voltages is greater than the fourth preset voltage threshold, the battery cell whose fourth current voltage is greater than the fourth preset voltage threshold is determined as the third battery cell to be balanced.

[0166] Optionally, in the above technical solution, the first preset voltage threshold V1 is: V1=V′1+V diff , the second preset voltage threshold V2 is: V2 = V′2 + V diff , the third preset voltage threshold V3 is: V3 = V′3 + ΔV, and the fourth preset voltage threshold V4 is: V4 = V′4 + ΔV;

[0167] Wherein, ΔV=U+(X×ΔT+Y)×I, V′1 represents the minimum value of all second current voltages, V′2 represents the minimum value of all third current voltages, V′3 represents the minimum value of all fourth current voltages, V′4 represents the preset voltage, V diff It represents the preset sampling voltage error value, ΔT represents the temperature difference between the cells, X represents the change value of the internal resistance of any cell when ΔT changes by 1°C, Y represents the internal resistance of any cell, I represents the balancing current, and U represents the preset sampling voltage error value corresponding to the balancing current of 0A.

[0168] Optionally, in the above technical solution, a correction module is further included, and the correction module is used to:

[0169] Correcting the amount of electricity to be balanced of each battery cell according to the health status of the power battery pack to obtain a corrected amount of electricity to be balanced of each battery cell to be balanced;

[0170] The process of obtaining the balancing time of each battery cell by the acquisition module 210 is as follows:

[0171] The balancing time of each battery cell is obtained according to the balancing current and the corrected amount of electricity to be balanced of each battery cell to be balanced.

[0172] The parameters and steps of each unit module implementing corresponding functions in the battery balancing control system 200 of the present invention can refer to the parameters and steps in the embodiment of the battery balancing control method above, which will not be described in detail here.

[0173] A storage medium of the present invention stores instructions, and when a computer reads the instructions, the computer executes any one of the above-mentioned battery balancing control methods.

[0174] An electronic device of the present invention comprises a processor and the above-mentioned storage medium, wherein the processor executes instructions in the storage medium. The electronic device may be a computer, a mobile phone or a controller.

[0175] A vehicle of the present invention comprises the above-mentioned electronic device.

[0176] Those skilled in the art will appreciate that the present invention may be implemented as a system, method or computer program product.

[0177] Therefore, the present disclosure may be specifically implemented in the following forms, namely: it may be completely hardware, it may be completely software (including firmware, resident software, microcode, etc.), or it may be a combination of hardware and software, generally referred to herein as a "circuit", "module" or "system". In addition, in some embodiments, the present invention may also be implemented in the form of a computer program product in one or more computer-readable media, and the computer-readable medium contains computer-readable program code.

[0178] Any combination of one or more computer-readable media can be used. Computer-readable media can be computer-readable signal media or computer-readable storage media. Computer-readable storage media can be, for example, but not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or devices, or any combination of the above. More specific examples (non-exhaustive list) of computer-readable storage media include: electrical connections with one or more wires, portable computer disks, hard disks, random access memories (RAM), read-only memories (ROM), erasable programmable read-only memories (EPROM or flash memory), optical fibers, portable compact disk read-only memories (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the above. In this document, computer-readable storage media can be any tangible medium containing or storing a program, which can be used by an instruction execution system, device or device or used in combination with it.

[0179] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A battery balancing control method, characterized in that: include: According to the balancing current and the amount of electricity to be balanced of each cell in the power battery pack, the balancing time of each cell is obtained; Determine a target balancing strategy according to the BMS state of the power battery pack and the state data of the power battery pack; Based on the balancing time of each battery cell and in combination with the target balancing strategy, the power battery pack is balanced; The process of obtaining the amount of electricity to be balanced of each battery cell in the power battery pack includes: When the power battery pack is in a fully charged state, a first resting time is determined according to a first current ambient temperature of the power battery pack, a first current power of each battery cell of the power battery pack after the first resting time is obtained, and a difference between the first current power of any battery cell and a first preset power threshold is determined as the power to be balanced of the battery cell, until the power to be balanced of each battery cell is obtained, wherein the first preset power threshold refers to: a minimum value of the first current power of each battery cell of the power battery pack after the first resting time; Alternatively, when the power battery pack is in a non-fully charged state, a second resting time is determined according to a second current ambient temperature of the power battery pack, a first current voltage of any battery cell of the power battery pack after the second resting time is obtained, and a second current power of the battery cell is obtained according to the first current voltage of the battery cell, and a difference between the second current power of any battery cell and a second preset power threshold is determined as the power to be balanced of the battery cell, until the power to be balanced of each battery cell is obtained, wherein the second preset power threshold refers to: the minimum value of the second current power of each battery cell of the power battery pack after the second resting time; The determining a target balancing strategy according to the BMS state of the power battery pack and the state data of the power battery pack includes: When the BMS state is the driving state, and when the state data of the power battery pack meets the first preset condition, a first balancing strategy is determined as the target balancing strategy, and the first balancing strategy is: a battery cell whose second current voltage is greater than a first preset voltage threshold is determined as a first battery cell to be balanced, at least one first battery cell to be balanced is obtained, and each first battery cell to be balanced is discharged; When the BMS state is a power-off state, and when the state data of the power battery pack meets a second preset condition, a second balancing strategy is determined as the target balancing strategy, and the second balancing strategy is: a cell having a third current voltage greater than a second preset voltage threshold is determined as a second cell to be balanced, at least one second cell to be balanced is obtained, and each second cell to be balanced is discharged; When the BMS state is a charging state, when the discharge time of each discharged battery cell reaches the balancing time of the corresponding battery cell, and when the state data of the power battery pack meets the third preset condition, a third balancing strategy is determined as the target balancing strategy, and the third balancing strategy is: determining at least one third battery cell to be balanced according to the fourth preset condition, and discharging each third battery cell to be balanced; The fourth preset condition is: when the fourth current voltage of each battery cell is greater than the preset voltage limit, the battery cell whose fourth current voltage is greater than the third preset voltage threshold is determined as the third battery cell to be balanced; or, when the maximum voltage among all fourth current voltages is greater than the fourth preset voltage threshold, the battery cell whose fourth current voltage is greater than the fourth preset voltage threshold is determined as the third battery cell to be balanced.

2. A battery balancing control method according to claim 1, characterized in that: The first preset voltage threshold V1 is: V1=V1 ′ +V diff , the second preset voltage threshold V2 is: V2 = V2 ′ +V diff , the third preset voltage threshold V3 is: V3 = V3 ′ +ΔV, the fourth preset voltage threshold V4 is: V4=V4 ′ +ΔV; Among them, ΔV=U+(X×ΔT+Y)×I, V1 ′ Indicates the minimum value of all second current voltages, V2 ′ Indicates the minimum value of all third current voltages, V3 ′ Indicates the minimum value of all fourth current voltages, V4 ′ Indicates the preset voltage, V diff represents the preset sampling voltage error value, ΔT represents the temperature difference between the cells, X represents the change value of the internal resistance of any cell when ΔT changes by 1°C, Y represents the internal resistance of any cell, I represents the balancing current, and U represents the preset sampling voltage error value corresponding to the balancing current of 0A.

3. A battery balancing control method according to any one of claims 1 to 2, characterized in that: Also includes: Correcting the amount of electricity to be balanced of each battery cell according to the health status of the power battery pack to obtain a corrected amount of electricity to be balanced of each battery cell to be balanced; The step of obtaining the balancing time of each battery cell according to the balancing current and the amount of electricity to be balanced of each battery cell includes: The balancing time of each battery cell is obtained according to the balancing current and the corrected amount of electricity to be balanced of each battery cell to be balanced.

4. A battery balancing control system, characterized in that: It includes an acquisition module, a determination module and a balancing module; The acquisition module is used to obtain the balancing time of each battery cell according to the balancing current and the amount of electricity to be balanced of each battery cell in the power battery pack; The determination module is used to: determine a target balancing strategy according to the BMS state of the power battery pack and the state data of the power battery pack; The balancing module is used to balance the power battery pack based on the balancing time of each battery cell and in combination with the target balancing strategy; The acquisition module is specifically used for: When the power battery pack is in a fully charged state, a first resting time is determined according to a first current ambient temperature of the power battery pack, a first current power of each battery cell of the power battery pack after the first resting time is obtained, and a difference between the first current power of any battery cell and a first preset power threshold is determined as the power to be balanced of the battery cell, until the power to be balanced of each battery cell is obtained, wherein the first preset power threshold refers to: a minimum value of the first current power of each battery cell of the power battery pack after the first resting time; Alternatively, when the power battery pack is in a non-fully charged state, a second resting time is determined according to a second current ambient temperature of the power battery pack, a first current voltage of any battery cell of the power battery pack after the second resting time is obtained, and a second current power of the battery cell is obtained according to the first current voltage of the battery cell, and a difference between the second current power of any battery cell and a second preset power threshold is determined as the power to be balanced of the battery cell, until the power to be balanced of each battery cell is obtained, wherein the second preset power threshold refers to: the minimum value of the second current power of each battery cell of the power battery pack after the second resting time; The determination module is specifically used for: When the BMS state is the driving state, and when the state data of the power battery pack meets the first preset condition, a first balancing strategy is determined as the target balancing strategy, and the first balancing strategy is: a battery cell whose second current voltage is greater than a first preset voltage threshold is determined as a first battery cell to be balanced, at least one first battery cell to be balanced is obtained, and each first battery cell to be balanced is discharged; When the BMS state is a power-off state, and when the state data of the power battery pack meets a second preset condition, a second balancing strategy is determined as the target balancing strategy, and the second balancing strategy is: a cell having a third current voltage greater than a second preset voltage threshold is determined as a second cell to be balanced, at least one second cell to be balanced is obtained, and each second cell to be balanced is discharged; When the BMS state is a charging state, when the discharge time of each discharged battery cell reaches the balancing time of the corresponding battery cell, and when the state data of the power battery pack meets the third preset condition, a third balancing strategy is determined as the target balancing strategy, and the third balancing strategy is: determining at least one third battery cell to be balanced according to the fourth preset condition, and discharging each third battery cell to be balanced; The fourth preset condition is: when the fourth current voltage of each battery cell is greater than the preset voltage limit, the battery cell whose fourth current voltage is greater than the third preset voltage threshold is determined as the third battery cell to be balanced; or, when the maximum voltage among all fourth current voltages is greater than the fourth preset voltage threshold, the battery cell whose fourth current voltage is greater than the fourth preset voltage threshold is determined as the third battery cell to be balanced.

5. A storage medium, characterized in that: The storage medium stores instructions, and when a computer reads the instructions, the computer executes a battery balancing control method according to any one of claims 1 to 3.

6. An electronic device, characterized in that: The invention comprises a processor and the storage medium as claimed in claim 5, wherein the processor executes instructions in the storage medium.

7. A vehicle, characterized in that: An electronic device comprising the electronic device described in claim 6.

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