Balancing control method and device and nonvolatile storage medium

Abstract

The invention discloses a balance control method and device and a nonvolatile storage medium. The method comprises the following steps: acquiring record data of a battery pack; and when the recorded data indicates that the battery pack is in the current charging and discharging period, when the battery pack does not complete the charging equalization processing and the battery pack is in the final discharging period, the charging equalization processing of the battery pack is completed according to the uncompleted duration of the uncompleted charging equalization processing. The technical problem that the battery equalization effect is not ideal in the prior art is solved.

Description

Technical Field

[0001] The present application relates to the technical field of battery management systems and the technical field of balancing, and in particular to a balancing control method, device and non-volatile storage medium. Background Art

[0002] The equalization strategy of charge equalization and discharge equalization of the battery pack during the charge and discharge process has an important impact on the equalization performance of the battery pack. During the charge and discharge process, in order to extend the service life of the battery, the battery pack needs to be equalized to suppress the possible differences between the batteries in the battery pack. The differences between the batteries in the battery pack may cause inconsistent battery states in the battery pack, which in turn affects the equalization performance of the battery pack. Compared with ternary batteries, lithium iron phosphate has higher safety and cycle life, so it is increasingly used in the field of electric vehicles. However, the plateau characteristics of lithium iron phosphate batteries make it difficult to calculate and obtain the relationship between the single cell voltage and the actual state of charge SOC (State of Charge) during the plateau period. Therefore, the battery pack equalization problem of lithium iron phosphate batteries becomes particularly important. The relevant technology simply uses the voltage difference to judge and start the equalization.

[0003] Passive balancing is an energy dissipative balancing method. Due to the temperature difference and aging degree between cells, there is a risk of misbalancing if the voltage difference is only judged. At the same time, the passive balancing current itself is small and the efficiency is low. Differences in user usage conditions may also make it more difficult to trigger balancing, and specific balancing targets are difficult to control, resulting in unsatisfactory balancing efficiency.

[0004] To address the above-mentioned problems, no effective solution has been proposed yet. Summary of the invention

[0005] The embodiments of the present application provide a balancing control method, device and non-volatile storage medium to at least solve the technical problem of unsatisfactory battery balancing effect in the related art.

[0006] According to one aspect of an embodiment of the present application, a balancing control method is provided, comprising: obtaining recorded data of a battery pack; when the recorded data indicates that the battery pack has not completed the charging balancing process in the current charging and discharging cycle, and the battery pack is at the end of the discharge, completing the charging balancing process of the battery pack according to the unfinished duration of the unfinished charging balancing process. By giving priority to ensuring that the last unfinished charging balancing process is completed, mutual interference between charging and discharging balancing strategies is avoided, unnecessary energy dissipation is reduced, and the overall energy efficiency of the battery system is improved.

[0007] Optionally, the method further includes: when the recorded data indicates that the battery pack has not performed charge equalization processing in the current charge and discharge cycle, allowing the battery pack to perform discharge equalization processing. Determining different equalization methods according to different working conditions is conducive to improving the adaptability to different application scenarios.

[0008] Optionally, the method further includes: determining the first single-cell charge state corresponding to each of the multiple single cells included in the battery pack according to the predetermined charge and discharge calibration data, wherein the first single-cell charge state is the charge state of the corresponding single cell at the end of charging; determining the first target single cell that needs to be charged and balanced among the multiple single cells based on the equalization target value of the battery pack and the first single-cell charge state corresponding to each of the multiple single cells, wherein the equalization target value indicates the capacity deviation allowed between the multiple single cells; determining the first equalization duration according to the first single-cell charge state corresponding to the first target single cell and the first minimum charge state of the multiple single cells at the end of charging; and performing charge and balance processing on the first target single cell for the first equalization duration. By accurately calculating the single-cell charge state at the end of charging, the SOC consistency of all single cells in the battery pack when fully charged is ensured, which helps to extend the service life of the entire battery pack and improve the charging and discharging efficiency of the battery.

[0009] Optionally, based on the equalization target value of the battery pack and the first single-cell charge states corresponding to the multiple single-cell batteries, the first target single-cell battery that needs to be charged and equalized is determined, including: determining the sum of the first minimum charge state and the equalization target value as the first judgment threshold; determining the single-cell battery whose first single-cell charge state is greater than the first judgment threshold among the multiple single-cell batteries as the first target single-cell battery. By determining the first judgment threshold, it is ensured that only the single-cell battery that really needs to be equalized is selected as the first target single-cell, avoiding over-equalization or mis-equalization, improving the accuracy of passive equalization control, and effectively avoiding overcharging of some single-cell batteries due to improper equalization strategies, thereby protecting battery health and extending battery life.

[0010] Optionally, the method further includes: determining the first boundary value of the platform range of the battery pack based on the charging curve of the battery pack, wherein the independent variable of the charging curve is the state of charge, the dependent variable is the cell voltage, the platform range is the state of charge range determined based on the nonlinear cell voltage change generated by the battery pack, and the first boundary value is the boundary value of the state of charge close to the full charge state in the platform range; when the first minimum state of charge is less than the first boundary value, assigning the first minimum state of charge to the first boundary value. Through the above processing, it is possible to more accurately determine when to start the equalization at the end of charging, avoid the difficulty of equalization judgment caused by small voltage changes in the platform period, and improve the accuracy and reliability of the equalization strategy.

[0011] Optionally, the method further includes: in the case where discharge equalization processing is allowed to be performed on the battery pack, determining the second single-cell charge state corresponding to each of the multiple single cells included in the battery pack according to the predetermined charge and discharge calibration data, wherein the second single-cell charge state is the charge state of the corresponding single cell at the end of discharge; based on the equalization target value of the battery pack and the second single-cell charge state corresponding to each of the multiple single cells, determining the second target single cell among the multiple single cells that need to be subjected to discharge equalization processing, wherein the equalization target value indicates the capacity deviation allowed between the multiple single cells; determining the second equalization time according to the second single-cell charge state corresponding to the second target single cell and the second minimum charge state of the multiple single cells at the end of discharge; and performing discharge equalization processing on the second target single cell for the second equalization time. Through the above processing, it is ensured that even if the battery is not fully equalized at the end of charging, the SOC consistency can be maintained at the end of the discharge cycle, thereby optimizing the overall performance of the battery pack.

[0012] Optionally, based on the equalization target value of the battery pack and the second single-cell charge states corresponding to the multiple single-cell batteries, the second target single-cell battery that needs to be discharged and equalized is determined, including: determining the aging coefficient based on the battery health state of the battery pack; determining the sum of the second minimum charge state, the aging coefficient, and the equalization target value as the second judgment threshold; determining the single-cell battery whose corresponding second single-cell charge state is greater than the second judgment threshold among the multiple single-cell batteries as the second target single-cell battery. Through the above processing, since the aging inconsistency is taken into account, unnecessary equalization is avoided when the battery health state is not good, the energy loss of the battery system is reduced, and the service life of the battery is extended.

[0013] Optionally, the charge and discharge calibration data is determined based on the corresponding relationship between battery temperature, state of charge, and single cell voltage under a predetermined battery health state. Through the above processing, it is ensured that the balancing strategy can adapt to the current state of the battery at different stages of the battery life cycle, thereby improving the overall performance and service life of the battery.

[0014] According to another aspect of an embodiment of the present application, a balancing control device is provided, including: a data acquisition module, used to acquire recorded data of a battery pack; and a balancing strategy module, used to complete the charging balancing processing of the battery pack according to the unfinished time length of the unfinished charging balancing processing when the recorded data indicates that the battery pack has not completed the charging balancing processing in the current charging and discharging cycle and the battery pack is at the end of the discharge.

[0015] According to another aspect of an embodiment of the present application, a non-volatile storage medium is provided, wherein the non-volatile storage medium stores a plurality of instructions, and the instructions are suitable for being loaded by a processor and executing any one of the balancing control methods.

[0016] In the embodiment of the present application, by acquiring the recorded data of the battery pack, when the recorded data indicates that the battery pack has not completed the charge equalization process in the current charge and discharge cycle, and the battery pack is at the end of discharge, the charge equalization process of the battery pack is completed according to the unfinished duration of the unfinished charge equalization process. The purpose of avoiding the mutual interference between the charge equalization and discharge equalization mechanisms is achieved, and the technical effect of improving the battery equalization efficiency is achieved, thereby solving the technical problem of unsatisfactory battery equalization effect in the related art. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0018] Figure 1 is a flow chart of an optional balancing control method provided according to an embodiment of the present application;

[0019] Figure 2 is a schematic diagram of a first balancing principle of an optional balancing control method provided according to an embodiment of the present application;

[0020] Figure 3 is a first schematic diagram of an optional balancing control method provided according to an embodiment of the present application;

[0021] Figure 4 is a second schematic diagram of an optional balancing control method provided according to an embodiment of the present application;

[0022] Figure 5 is a schematic diagram of a second balancing principle of an optional balancing control method provided according to an embodiment of the present application;

[0023] Figure 6 is a strategy diagram of an optional balancing control method provided according to an embodiment of the present application;

[0024] Figure 7 It is a schematic diagram of an optional balancing control device provided according to an embodiment of the present application. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0026] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0027] According to an embodiment of the present application, a method embodiment of balancing control is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0028] Figure 1 is a flow chart of an optional balancing control method according to an embodiment of the present application, such as Figure 1 As shown, the method comprises the following steps:

[0029] Step S102, obtaining recorded data of the battery pack;

[0030] Step S104, when the recorded data indicates that the battery pack has not completed the charge equalization process in the current charge and discharge cycle and the battery pack is at the end of discharge, the charge equalization process of the battery pack is completed according to the unfinished time of the unfinished charge equalization process.

[0031] It can be understood that the recorded data of the charge and discharge cycle is obtained from the battery pack to determine whether the battery pack has completed the passive equalization processing at the end of the charge in the current charge and discharge cycle. If the recorded data indicates that the battery pack has not completed the charge equalization in the current cycle, and the battery pack is now at the end of the discharge, the charge equalization processing will be completed first according to the remaining time of the last unfinished charge equalization processing (i.e., the unfinished duration). By ensuring that the last unfinished charge equalization processing is completed first, mutual interference between the charge and discharge equalization strategies is avoided, unnecessary energy dissipation is reduced, and the overall energy efficiency of the battery system is improved. The effective coordination and execution of the balancing strategy helps to reduce the inconsistency between battery cells, thereby reducing the situation of local overcharge or over-discharge, helping to extend the cycle life of the entire battery pack and reducing battery maintenance costs.

[0032] Optionally, the above battery pack can be applied to a variety of power equipment, such as drones, electric vehicles, electric ships, etc.

[0033] Optionally, when the recorded data indicates that the battery pack has not completed the charge equalization process in the current charge and discharge cycle, and the battery pack is at the end of discharge, the discharge equalization process is also prohibited. It should be noted that the method of determining the charge equalization at the end of charging and the method of determining the discharge equalization at the end of discharging are both passive equalization, but the monomer batteries that need to be equalized may not be the same, and the duration of the equalization is also different. In the case that the previous charge equalization is not completed, this embodiment focuses on the consistency of the remaining chargeable amount, that is, ensuring that all monomers reach a consistent SOC when charging, so the priority of the charging end equalization is higher than the discharge end equalization. This means that if the battery management system BMS (Battery Management System) has stored the remaining equalization time of the charging end, even if there is an inconsistency in the SOC between the monomers during the discharge process, the equalization calculation and operation of the discharge end will not be performed immediately, but wait until the equalization time of the charging end is completely executed, and then judge whether the discharge end needs to be equalized according to the situation.

[0034] It ensures that the balancing effect during charging will not be destroyed by temporary triggering during discharging. At the same time, after charging, the balancing strategy during discharging can be dynamically adjusted according to the aging inconsistency coefficient to improve the overall performance and life of the battery pack. Through the above strategy, this embodiment not only improves the probability of balancing triggering of lithium iron phosphate batteries during charging and discharging, but also effectively avoids the risk of misbalancing, further enhancing the performance and safety of the battery pack.

[0035] Optionally, taking the battery pack as an electric vehicle as an example, when the vehicle is plugged in for charging and reaches the normal charging stop time, the battery management system BMS will record the voltage distribution of all cells and calculate the SOC of each cell according to the preset SOC-voltage relationship table. If the system determines that some cells need to be charged and balanced at this time, their remaining balance time will be calculated and stored. In the battery's charge and discharge cycle, if the BMS detects that equalization is required at the end of discharge, but the system has stored an unfinished charge equalization time, then the BMS will give priority to executing the stored charge equalization remaining time, and the calculation and execution of discharge equalization will be temporarily shelved until the charge equalization is completely completed. Through priority management, a smooth transition between the charging and discharging cycles is achieved, ensuring the realization of the end-of-charge equalization goal. At the same time, a flexible execution mechanism is provided for the end-of-discharge equalization, ensuring the comprehensiveness and efficiency of the battery balancing strategy.

[0036] Optionally, the above passive balancing is a technical means used in a battery management system (BMS) to adjust the consistency of the state of charge (SOC) of a single cell in a battery pack, and is mainly used in battery packs composed of multiple batteries connected in series or in parallel, such as electric vehicles and energy storage systems. Its working principle is based on energy dissipation, that is, by introducing resistors or other energy dissipation elements between the single cells in the battery pack, the charge state or voltage difference between the cells is balanced.

[0037] During the battery charging or discharging process, due to the inconsistency of manufacturing process, use environment or aging degree, the single cells in the battery pack may have unbalanced SOC or voltage. Passive balancing technology monitors these parameter differences. When it detects that the SOC or voltage of a single cell is higher than that of other cells, the BMS will activate the energy dissipation element on the single cell, such as the balancing resistor, so that the energy higher than the average value is converted into heat energy through the resistor and dissipated. In this way, the single cell with higher energy will charge at a slower rate or discharge at a faster rate until its SOC or voltage is close to or consistent with other cells in the battery pack. Only one resistor needs to be connected in parallel to each battery cell, and the hardware cost is relatively low. Since the energy dissipation method is relatively mild, it will not cause drastic energy fluctuations to the battery pack, reducing the potential safety risks of the system. The BMS can adjust the balancing process by controlling the on and off of the balancing resistor to achieve automated balancing management.

[0038] Optionally, both the above-mentioned charge balancing and discharge balancing belong to passive balancing. Since charge balancing is also a small current discharge, it is only to determine the balancing method at the end of charging, locate the first target cell to be balanced, and the first balancing time for the first target cell, which is different from the discharge balancing method. It can be understood that the above-mentioned charge balancing can be performed during the discharge process of the battery pack.

[0039] Optionally, Figure 2 is a schematic diagram of a first balancing principle of an optional balancing control method provided according to an embodiment of the present application, such as Figure 2 As shown in the figure, if there are cell 1 and cell 2, the amount of electricity discharged and charged by cell 1 is greater than that of cell 2. In a battery pack, the performance difference of the single cells, such as inconsistent capacity decay, will directly affect the maximum available capacity of the entire battery pack. The following will explain the energy flow and capacity limitation of cell 1 and cell 2 during the charging and discharging process in different situations.

[0040] During the charging process, all cells are charged until they reach a certain set SOC (state of charge) or voltage limit. If the charging characteristics of cell 1 and cell 2 are different, such as cell 1 has a better state of health (SOH) and a higher capacity, then under the same charging conditions, cell 1 can accept more charge, that is, more electricity will be charged. However, the charging of the battery pack is usually monitored by the battery management system (BMS) to avoid overcharging any single cell, which may cause damage or safety problems to the battery. The BMS monitors the voltage and SOC of all cells, and once it detects that any single cell reaches the voltage limit or SOC target, it will stop the charging process of the entire battery pack, even if the other cells are not yet fully charged. In this case, if cell 2 has a lower capacity or a slower SOC rise, the BMS will stop charging when cell 2 reaches its highest acceptable SOC, even if the SOC of cell 1 has not yet reached the highest. This means that even if cell 1 has a larger capacity, it cannot charge more electricity, and the actual available capacity of the entire battery pack will be limited by the capacity of cell 2, which is the cell with the smallest capacity.

[0041] During discharge, all cells will jointly provide energy until the minimum SOC or voltage limit. If the capacity of cell 1 is higher than that of cell 2, then under the same discharge conditions, cell 1 can release more electricity, that is, more electricity will be released. Once cell 2 reaches its minimum safe SOC, the BMS will stop discharging, even if the SOC of cell 1 is still higher. At this point, the remaining energy in cell 1 will not be available, and the dischargeable capacity of the entire battery pack is also limited by the capacity of cell 2.

[0042] In order to ensure the long-term health and safe operation of the battery pack, the BMS must manage the charging and discharging process of the entire battery pack to prevent any single cell from being overcharged or over-discharged. Therefore, in a battery pack, the maximum available capacity always depends on the single cell with the smallest capacity, which can be understood as the "barrel effect", that is, the performance of the entire battery pack is determined by the shortest single cell ("the shortest board in the barrel"). Through an effective balancing strategy, the impact of this performance difference can be minimized and the overall utilization and life of the battery pack can be improved.

[0043] Whether charging or discharging, the overall performance and available capacity of a battery pack is always limited by the worst performing cell (e.g. Figure 2For the example of single cell 2), the plateau characteristics of lithium iron phosphate batteries make the capacity difference between single cells more critical at the end of discharge. The capacity attenuation of single cell 2 is higher than that of single cell 1, so there is a capacity inconsistency, and the actual capacity of the whole pack depends on the lowest single cell. Passive balancing, as an energy-consuming balancing method, can choose to start balancing at the high or low end of the power. The difference is that starting balancing at the high end of the power is based on the principle of consistency of the remaining chargeable amount, and the ideal goal is to fully charge all cells at the same time. Starting balancing at the low end of the power is based on the principle of consistency of the remaining dischargeable amount, and the ideal goal is to empty all cells at the same time. Adopt Figure 2 In implementation method A, the capacity of the decaying cells can be fully utilized while ensuring that each cell is fully charged as much as possible at the same time. The available energy of the entire battery pack of method A can also be maximized.

[0044] In an optional embodiment, the method further includes: when the recorded data indicates that the battery pack has not performed a charge equalization process in the current charge and discharge cycle, allowing a discharge equalization process to be performed on the battery pack.

[0045] It can be understood that through the acquired recorded data, the equalization processing at the end of charging has not been performed in the current cycle, so the equalization processing at the end of discharging is allowed to be performed to make up for the lack of charging equalization. Even if equalization is not performed at the end of charging, the SOC consistency of the cells in the battery pack can be dynamically maintained through the equalization processing at the end of discharging, reducing the energy waste and battery performance degradation caused by SOC imbalance. In the case where charging equalization is not performed, the equalization processing at the end of discharging can be started according to the discharge cut-off voltage to compensate for the energy difference between the cells in time. In the case of SOC inconsistency caused by battery aging or temperature changes, the use of immediate equalization processing is conducive to improving the adaptability to different application scenarios.

[0046] Optionally, based on the principle of consistency of remaining chargeable capacity, triggering can be performed at both the charging end and the discharging end, thereby increasing the probability of balanced triggering.

[0047] In an optional embodiment, the method further includes: determining first single-cell charge states corresponding to a plurality of single-cell batteries included in the battery pack according to predetermined charge and discharge calibration data, wherein the first single-cell charge state is the charge state of the corresponding single-cell battery at the end of charging; determining a first target single cell among the plurality of single-cell batteries that requires charge equalization processing based on a target value for balancing the battery pack and first single-cell charge states corresponding to the plurality of single-cell batteries, wherein the target value for balancing represents a capacity deviation allowed between the plurality of single-cell batteries; determining a first equalization duration according to the first single-cell charge state corresponding to the first target single cell and a first minimum charge state of the plurality of single-cell batteries at the end of charging; and performing charge equalization processing on the first target single cell for the first equalization duration.

[0048] It can be understood that the predetermined charge and discharge calibration data is used to calculate and determine the state of charge (SOC) of each single cell in the battery pack at the end of charging, that is, the first single cell state of charge. According to the equalization target value of the battery pack (that is, the allowable capacity deviation), the first target single cell that needs to be charged and equalized is screened out from multiple single cells. The equalization target value reflects the allowable SOC difference between the cells in the battery pack in order to ensure the overall performance and life of the battery. Based on the state of charge of the first target single cell, the minimum state of charge of all cells at the end of charging (the first minimum state of charge) and the current effective equalization current, the first equalization duration is calculated, that is, the time required for charge equalization. According to the calculated first equalization duration, charge equalization is performed on the first target single cell to reduce the capacity deviation between it and other cells in the battery pack.

[0049] By accurately calculating the state of charge of the single cell at the end of charging, the SOC consistency of all single cells in the battery pack when fully charged is ensured, which helps to extend the service life of the entire battery pack and improve the charging and discharging efficiency of the battery. Since the charge balancing process is based on the principle of consistency of the remaining charge capacity, the voltage-SOC mapping relationship of the single cell under different aging states (SOH, State of Health) is considered, making the balancing strategy more intelligent, reducing the misbalancing caused by simple voltage differences, thereby avoiding unnecessary energy waste.

[0050] Optionally, for charging terminal balancing, at different test temperatures, the whole vehicle is plugged in and charged according to the BMS's established requested current, and the complete charging process data is recorded. Test data acquisition can also use a single battery cell and charge it according to a specific charging MAP. Obtain the SOC values ​​corresponding to different temperatures and voltages at the charging terminal. At the same time, considering aging, different SOHs need to be tested. In actual use, during the plug-in charging process, when the highest single cell voltage reaches full charge, record the voltage distribution of all cells, calculate the dynamic SOC of each single cell voltage based on the preset data lookup table, calculate the deviation of all single cell SOC from the lowest single cell SOC, and screen out the cells that need to be balanced based on the balancing target, and calculate the remaining balancing time of the cells to be balanced based on the actual effective balancing current.

[0051] In an optional embodiment, based on the balancing target value of the battery pack and the first single-cell charge states corresponding to the multiple single-cell batteries, a first target single-cell battery that needs to be charged and balanced is determined, including: determining the sum of the first minimum charge state and the balancing target value as a first judgment threshold; determining a single-cell battery whose corresponding first single-cell charge state among the multiple single-cell batteries is greater than the first judgment threshold as the first target single-cell battery.

[0052] It can be understood that the current first single-cell state of charge SOC(i) of each single cell is determined based on the balancing target value of the battery pack (such as denoted as Ctgt). First, determine the first judgment threshold, which is the sum of the first minimum state of charge (SOC1min) and the balancing target value. Screen out all single cells whose corresponding first single-cell state of charge is greater than the first judgment threshold as the first target single cell that needs to be charged and balanced. By determining the first judgment threshold, it is ensured that only the single cells that really need to be balanced are selected as the first target single cells, avoiding over-balancing or mis-balancing, improving the accuracy of passive balancing control, and effectively avoiding overcharging of some single cells due to improper balancing strategies, thereby protecting battery health and extending battery life.

[0053] In an optional embodiment, the method further includes: determining a first boundary value of a platform range of the battery pack based on a charging curve of the battery pack, wherein the independent variable of the charging curve is the state of charge, the dependent variable is the single cell voltage, the platform range is a state of charge range determined based on nonlinear single cell voltage changes generated by the battery pack, and the first boundary value is a boundary value of the state of charge close to a full charge in the platform range; and when the first minimum state of charge is less than the first boundary value, the first minimum state of charge is assigned to the first boundary value.

[0054] It can be understood that the plateau period is a special area of ​​lithium iron phosphate batteries, during which the battery voltage changes very little, even if the SOC (state of charge) changes significantly. In order to accurately trigger the equalization at the end of charging, the first boundary value of the platform range is determined, that is, the boundary at the end close to the fully charged state of charge. The range of the platform period is determined by analyzing the charging curve of the battery pack, which takes the state of charge (SOC) as the independent variable and the cell voltage as the dependent variable. Once the first boundary value of the platform range is determined, if the minimum state of charge detected during the actual charging and discharging process (that is, the cell with the lowest SOC in the battery pack) is less than this first boundary value, then this minimum state of charge will be adjusted to the first boundary value, thereby ensuring that all cells are operating in the area outside the plateau period, and it can be more accurately determined when to start the equalization at the end of charging, avoiding the difficulty of equalization judgment caused by small voltage changes during the plateau period, and improving the accuracy and reliability of the equalization strategy.

[0055] According to the project requirements, determine the balancing target value Ctgt. Generally, the balancing target of the whole battery pack is 3% to 5% of the battery cell voltage deviation (the value is for reference only). It can be changed according to the project needs. The following methods can be used to determine the cells that need to be balanced:

[0056] SOC(i) > SOC1min + Ctgt (1)

[0057] The monomers satisfying the above formula (1) need to start balancing. For lithium iron phosphate batteries, if SOC1min is lower than the upper boundary of the plateau period, SOC1min is limited to the upper boundary of the plateau period.

[0058] Optionally, the time required for the monomer to be balanced is:

[0059] Tibal[i] = [SOC(i) – SOC1min – Ctgt]×Ct×60 / Ibal (2)

[0060] Among them, Ibal represents the effective balancing current, Tibal[i] represents the remaining balancing time of the i-th single cell, in minutes, and Ct represents the cell capacity at the current temperature. Based on the calculated remaining balancing time of each single cell, balancing begins. If the BMS needs to sleep during the balancing process, the remaining balancing time of each single cell needs to be stored in the storage device, and the balancing will continue after the BMS wakes up again. The charge balancing process based on SOC difference and balancing target value is an optimization of the balancing strategy while taking into account the inconsistency of battery aging. This helps to maintain SOC consistency throughout the life cycle of the battery pack, thereby improving the charge and discharge performance and cycle life of the battery pack.

[0061] Optionally, in order to control the duration of a single balancing, the maximum time of a single balancing can be limited. The resources required for balancing (such as heat dissipation system, balancing circuit, etc.) are limited, and long-term balancing may over-consume these resources and affect other functions of the battery system. By limiting the maximum time of a single balancing, it can be ensured that these resources can support other operations of the battery system while meeting the balancing requirements, so as to achieve reasonable allocation and effective utilization of resources. Long-term balancing will increase the thermal stress of the battery cells, which may cause battery performance degradation or shorten life. By controlling the balancing time, the battery cells can be prevented from being subjected to excessive thermal stress during the balancing process, which helps to protect the health of the battery cells and extend the battery life cycle. In addition, electric vehicle users tend to complete the charging or discharging process in a shorter time. Long-term balancing operations may affect the user experience, reduce the impact on the user's daily use, and improve convenience and satisfaction.

[0062] Optionally, the above-mentioned effective balancing current refers to the current that can actually flow through the balancing circuit when the battery management system (BMS) executes a passive balancing strategy, resulting in an effective reduction in the state of charge (SOC) or voltage difference between battery cells. During the balancing process, the size of the effective balancing current is directly related to the balancing efficiency and speed. When the BMS detects that the SOC or voltage of the single cells in the battery pack is inconsistent, a balancing resistor will be connected to the single cell with high SOC or high voltage to form a discharge loop. At this time, the actual current passing through the balancing resistor is the effective balancing current, which will dissipate the energy of this part of the single cell in the form of heat energy, thereby gradually reducing the difference between the cells.

[0063] The determination of the above effective balancing current needs to consider multiple factors, including battery characteristics (such as internal resistance, capacity, and health status SOH), the design of the balancing circuit (such as resistance value, circuit topology), the temperature of the battery pack, and the control logic of the BMS. In the passive balancing control strategy of lithium iron phosphate batteries, the size of the effective balancing current will affect the calculation of the remaining time for single-cell balancing. A larger effective balancing current can shorten the balancing time, but may increase energy loss and battery thermal load; while a smaller current reduces energy loss, the balancing speed is slower and prolongs the balancing cycle. It is necessary to find the best balance between balancing efficiency, energy loss, and battery safety.

[0064] In an optional embodiment, the method further includes: in a case where discharge balancing processing is allowed to be performed on the battery pack, determining second single-cell charge states corresponding to each of the multiple single-cell batteries included in the battery pack according to predetermined charge and discharge calibration data, wherein the second single-cell charge state is the charge state of the corresponding single-cell battery at the end of discharge; based on the balancing target value of the battery pack and the second single-cell charge states corresponding to the multiple single-cell batteries, determining a second target single-cell battery among the multiple single-cell batteries that needs to be discharged balancing processing, wherein the balancing target value indicates the capacity deviation allowed between the multiple single-cell batteries; determining a second balancing time according to the second single-cell charge state corresponding to the second target single-cell battery and the second minimum charge state of the multiple single-cell batteries at the end of discharge; and performing discharge balancing processing on the second target single-cell battery for the second balancing time.

[0065] It can be understood that when discharge equalization processing is allowed, the actual SOC (i.e., the second single-cell state of charge) of each single cell in the battery pack at the end of discharge is determined based on the preset charge and discharge calibration data, and the second target single cell that needs to be discharged equalized is determined based on the equalization target value of the battery pack and the second single-cell state of charge of each single cell, and then the discharge equalization duration is calculated, and the discharge equalization processing is performed. By accurately calculating the SOC of each single cell at the end of discharge and determining the single cell that needs to be equalized, this embodiment ensures that even if the charge is not completely equalized at the end, the SOC consistency can be maintained at the end of the discharge cycle, thereby optimizing the overall performance of the battery pack.

[0066] Optionally, at the end of battery discharge, the SOCs of all cells are statically corrected to obtain an accurate SOC value of each cell (ie, the second cell state of charge).

[0067] In an optional embodiment, based on the balancing target value of the battery pack and the second single-cell charge states corresponding to the multiple single-cell batteries, the second target single-cell batteries that need to be discharged and balanced are determined, including: determining the aging coefficient based on the battery health status of the battery pack; determining the sum of the second minimum state of charge, the aging coefficient, and the balancing target value as the second judgment threshold; determining the single-cell battery whose corresponding second single-cell charge state is greater than the second judgment threshold among the multiple single-cell batteries as the second target single-cell battery.

[0068] It can be understood that based on the battery health state (SOH) of the battery pack, the aging coefficient (λold) is determined, which reflects the degree of influence of battery aging on the discharge characteristics of the single cell. The second judgment threshold is determined based on the sum of the second minimum state of charge (SOC2min) at the end of discharge, the aging coefficient (λold) and the balancing target value (Ctgt). Among all single cells, the batteries whose second single cell state of charge is greater than the second judgment threshold are screened out as the second target cells that need to be discharged and balanced. By introducing the aging coefficient, the balancing strategy can better adapt to the dynamic changes of battery aging and improve the effectiveness of the balancing strategy throughout the life cycle of the battery. Because the aging inconsistency is taken into account, unnecessary balancing is avoided when the battery is in poor health, the energy loss of the battery system is reduced, and the service life of the battery is extended.

[0069] Optionally, dynamic adjustment of the aging coefficient makes the balancing target more precise, ensures the SOC consistency at the end of battery discharge, and improves the overall performance and reliability of the battery pack. By considering the battery health state (SOH) and aging inconsistency at the end of discharge to determine the cells that need to be discharged and balanced, the dynamic adjustment of the balancing strategy is achieved, which improves the intelligence and efficiency of the battery management system, reduces the risk of misbalancing, prolongs the battery life cycle, and optimizes the user experience of electric vehicles.

[0070] Optionally, after the monomer is statically corrected, determine the monomer that needs to be balanced:

[0071] SOC(i) > SOC2min+ Ctgt + λold (3)

[0072] Among them, λold is the consistency deviation coefficient of aging between cells, in percentage. If the aging consistency deviation is D% when the SOH is 80%, then when the SOH changes from 100% to 80%, λold changes between 0-D%. This change is affected by the user's working conditions and battery characteristics. It is preferred to perform interpolation processing on this coefficient as the SOH changes. The following mathematical expression can be used:

[0073] λold = 5×D - SOH×D / 20 (4)

[0074] In addition to the linear interpolation method, there are many other methods for processing consistency deviation coefficients (such as aging inconsistency coefficients), which can be selected or customized according to the actual use of the battery and data characteristics to more accurately reflect the aging differences between single cells in the battery pack. For example: by collecting a large amount of battery data at different SOH (health status), the data is fitted using a polynomial function to obtain a polynomial model that describes the change of the aging inconsistency coefficient with SOH.

[0075] If the relationship between the aging inconsistency coefficient and the SOH shows an exponential growth or decay, an exponential function may be used for fitting to more accurately reflect this changing trend.

[0076] The change of consistency may show different characteristics in different intervals of SOH. The SOH range can be divided into multiple segments, and independent interpolation or fitting methods can be used for each segment to improve the accuracy and adaptability of the model.

[0077] Machine learning techniques such as regression analysis, neural networks, or support vector machines can also be used to train a model based on historical data to predict the aging inconsistency coefficient at a specific SOH, which can automatically learn complex relationships in the data.

[0078] Using a fuzzy logic system, uncertainties such as the effect of temperature changes on the aging inconsistency coefficient can be handled. By defining fuzzy sets and fuzzy rules, a model that can handle imprecise information in the battery system can be created to estimate the consistency deviation coefficient.

[0079] In an optional embodiment, the charge and discharge calibration data is determined based on the corresponding relationship between the battery temperature, the state of charge, and the single cell voltage when the battery pack is in a predetermined battery health state.

[0080] It can be understood that the charge and discharge calibration data is the correspondence between the battery temperature, state of charge (SOC) and single cell voltage obtained through experiments under the predetermined battery health state (SOH) of the battery pack. It is used in the form of a SOC-voltage mapping table, which takes into account the influence of battery temperature and SOH and is an important basis for BMS to judge the battery status and execute the balancing strategy.

[0081] Optionally, there are multiple ways to obtain charge and discharge calibration data, which can be expressed in the form of SOC-cell voltage data table, for example: take charging calibration as an example to obtain scheme data, after the vehicle is fully stationary, start plug charging at low power according to the BMS request current at different temperatures, and record the charging process data. The above temperature conditions need to be based on the actual battery pack chargeable temperature range and the operating temperature of thermal management.

[0082] Based on the acquired data, the highest single cell voltage is used as the target voltage, and the reverse ampere-hour integration is started from the full charge point to obtain the dynamic SOC values ​​corresponding to different voltage points. The interval of dynamic SOC can be evaluated based on the data. If the voltage value corresponding to the unit SOC changes little, the SOC interval can be considered to be larger, otherwise it can be appropriately reduced.

[0083] The SOC-cell voltage data table at different temperatures is established, and the data points are only taken to the boundary point of the upper plateau period (i.e., the first boundary value of the platform range), as shown in Table 1. Considering that the dynamic response of the voltage will be different after aging, the charging strategy after aging is tested to obtain the SOC-voltage curve after aging, as shown in Table 2 and Table 3. The calibration curve of the battery health state SOH can be obtained according to the actual situation. The 100, 90, and 80 given in Tables 1, 2, and 3 are only reference SOHs, and the specific values ​​are only for illustration and are not specifically limited.

[0084] Table 1: Schematic diagram of the first calibration with SOH of 100

[0085]

[0086]

[0087] Table 2 Schematic diagram of the second calibration with SOH of 90

[0088]

[0089] Table 3 The third calibration diagram for SOH of 80

[0090]

[0091] Table 1, Table 2, and Table 3 are used as charge and discharge calibration data, SOC1, SOC2, etc. are schematic diagrams of different charge states, and T1, T2, etc. are different temperature points. The above charge and discharge calibration data are written into the control software of the battery management system, and the parameters between the tables are interpolated. When the vehicle is in normal state, plug-in charging begins. Under the premise that there is no excessive temperature difference fault, excessive pressure difference fault, or abnormal battery cell, the normal charging stop time is reached, and all single cell voltages V(i) and the temperature at this time are recorded, where i represents the identification of the single cell battery, and V represents the voltage. According to the preset Table 1, Table 2, and Table 3, the corresponding state of charge SOC(i) of each single cell is obtained by looking up the table.

[0092] By establishing a SOC-voltage mapping table for different SOHs, the BMS can dynamically respond to the aging of cells in the battery pack, ensuring that at different stages of the battery life cycle, the balancing strategy can adapt to the current state of the battery and improve the overall performance and service life of the battery.

[0093] Through the above step S102, the recorded data of the battery pack is obtained; in step S104, when the recorded data indicates that the battery pack has not completed the charge equalization process in the current charge and discharge cycle, and the battery pack is at the end of discharge, the charge equalization process of the battery pack is completed according to the unfinished time of the unfinished charge equalization process. The purpose of avoiding the mutual interference between the charge equalization and discharge equalization mechanisms is achieved, and the technical effect of improving the battery equalization efficiency is achieved, thereby solving the technical problem of unsatisfactory battery equalization effect in the related art.

[0094] Based on the above embodiments and optional embodiments, the present application proposes an optional implementation method, which is based on the principle of consistency of the remaining chargeable capacity, and mainly includes two parts: charging terminal balancing judgment and discharge terminal balancing judgment. The charging terminal balancing is based on the actual vehicle plug-in charging data or laboratory charging data, and calibrates the cell voltage-SOC mapping relationship under different SOH and temperature. In the actual vehicle plug-in charging process, when the charging terminal ends charging, all cell SOCs are calculated according to a preset table (i.e., an optional form of expression of charge and discharge calibration data), so as to determine the cell that needs to be balanced and calculate the remaining time for cell balancing. On the basis of ensuring the principle of consistency of the remaining chargeable capacity, a balancing strategy with a variable balancing target is proposed in the non-plateau period at the end of lithium iron phosphate discharge. The discharge end balancing target needs to increase the aging inconsistency coefficient between cells, and the coefficient changes with SOH. The cell that needs to be balanced is calculated based on the SOC value of each cell after static correction.

[0095] Figure 3 is a first schematic diagram of an optional balancing control method provided according to an embodiment of the present application, such as Figure 3 As shown, the charging terminal balancing control strategy process is illustrated.

[0096] S1, obtain solution data. After the vehicle is fully stationary, start plug charging at different temperatures from low power according to the current requested by the BMS, and record the charging process data. The temperature conditions here need to be based on the actual battery pack chargeable temperature range and the operating temperature of thermal management.

[0097] S2, solution data processing. According to the data obtained in S01, take the highest single cell voltage as the target voltage, start the reverse ampere-hour integration from the full charge point, and obtain the dynamic SOC values ​​corresponding to different voltage points. The interval of dynamic SOC can be evaluated based on the data. If the voltage value corresponding to the unit SOC changes little, the SOC interval can be considered to be larger, otherwise it can be appropriately smaller. Establish a SOC-cell voltage data table at different temperatures, and only take the data points to the boundary point of the upper plateau period, as shown in Table 1. Considering that the dynamic response of the voltage will be different after aging, the charging strategy after aging is tested to obtain the SOC-voltage curve after aging, as shown in Table 2 and Table 3; Optionally, the calibration curves of different SOHs can be obtained based on actual conditions. The 100, 90, and 80 given in the table are only reference SOHs.

[0098] S3, write Table 1, Table 2 and Table 3 into the software, and interpolate the parameters between the tables.

[0099] S4, when the vehicle is in normal condition, start plug-in charging. Under the premise that there is no excessive temperature difference fault, excessive pressure difference fault and battery cell abnormality, the normal charging stop time is reached, and all cell voltages V(i) and the temperature at this time are recorded. According to the preset Table 1, Table 2 and Table 3, the SOC(i) corresponding to each cell is obtained by looking up the table.

[0100] S5: According to the project requirements, determine the balance target value Ctgt (generally the whole package balance target is 3% to 5%, which can be changed according to project needs), and determine the monomer that needs to be balanced (i.e. the first target monomer):

[0101] SOC(i) > SOC1min + Ctgt (1)

[0102] The monomers satisfying the above formula (1) need to start balancing. In particular, for lithium iron phosphate batteries, if SOC1min is lower than the upper boundary of the plateau period, SOC1min is limited to the upper boundary of the plateau period.

[0103] S6, the time required for the monomer to be balanced is:

[0104] Tibal[i] = [SOC(i) – SOC1min – Ctgt]×Ct×60 / Ibal (2)

[0105] Where Ibal represents the effective balancing current, Tibal[i] represents the remaining balancing time of the ith single cell, in minutes, and Ct represents the cell capacity at the current temperature. Balancing starts based on the calculated remaining balancing time for each cell. If the BMS needs to sleep during the balancing process, the remaining balancing time for each cell needs to be stored in the storage device, and balancing will continue after the BMS wakes up again. If the remaining balancing time is not completely cleared, and the full charge moment balancing is triggered again, the new remaining balancing time will overwrite the old remaining time.

[0106] Choosing to enable balancing at the end of charging and at the end of discharging, considering consistency, the two are inherently conflicting. As the battery pack ages, the attenuation of the cells is definitely inconsistent. Under dynamic conditions, the cell voltage of the cell with high voltage at the low end may be relatively low after charging to the high end. During the aging process of lithium iron phosphate batteries, their capacity, internal resistance, and voltage characteristics will change. Even if SOC consistency is achieved through balancing at the end of charging, dynamic changes during discharge may cause differences again. If balancing is directly used at the end of discharge without considering the balancing effect at the end of charging, the cells that have been balanced may actually be balanced again. Balancing itself is an energy dissipation process. The balancing current is very small and the balancing time is long. The inappropriate activation strategy of charging balancing and discharging balancing may lead to frequent discharge balancing of battery cells, energy waste, and may also reduce the battery life. And usually the focus is on how much electricity the battery can discharge, corresponding to the consistency target of the remaining chargeable amount (so that the maximum charging capacity of the battery pack will be the largest).

[0107] In summary, this embodiment does not blindly start equalization according to voltage deviation, and prioritizes equalization at the end of charging to achieve better equalization effect. Considering the difficult operation of lithium iron phosphate plateau, and if the user does not fully charge for a long time, it may be difficult to trigger the equalization opportunity. On the basis of ensuring the consistency of the chargeable amount, a strategy of exploring the triggering of equalization at the end of discharge is proposed. Figure 5 is a schematic diagram of a second balancing principle of an optional balancing control method provided in an embodiment of the present application, such as Figure 5 As shown in the figure, there are three main cases for evaluating the consistency difference between monomers in the late aging period (taking 5% as an example, which may vary according to the actual situation), where C represents the discharge rate:

[0108] (1) If the aged cell is fully charged first and meets the balancing target value of 3%, and the normal cell is only charged to 97%, in this case, neither cell needs to be balanced. After discharging to the low end of the power, it is fully discharged and the normal cell still has 2% power left.

[0109] (2) If the normal cell is fully charged first and meets the balancing target of 3%, the abnormally aged cell is actually only charged to 92%. After being fully discharged, the normal cell still has 8% power left. At the low end of the power level, the normal cell shows that balancing needs to be turned on.

[0110] (3) If a normal cell and an abnormally aged cell are fully charged at the same time, after full discharge, the normal cell still has 5% power left, indicating that balancing needs to be turned on at the low end of the power level.

[0111] If the principle of consistency of remaining chargeable capacity needs to be met, after the charging terminal completes the balancing alignment, the SOC deviation at the low end of the power can reach 8%. If at this time the same balancing target as the charging terminal is followed, the normal cells will start mis-balancing, because at the high end of the power, the normal cells and abnormally aged cells have already met the balancing target and no longer need to start balancing.

[0112] Figure 4 is a second schematic diagram of an optional balancing control method provided according to an embodiment of the present application, such as Figure 4 As shown, the discharge end balance control strategy process is illustrated.

[0113] S7, at the end of battery discharge, all single-cell SOCs are statically corrected to obtain the accurate SOC value of each single cell.

[0114] S8, after the monomer is statically corrected, determine the monomer that needs to be balanced:

[0115] SOC(i) > SOC2min+ Ctgt + λold (3)

[0116] Among them, λold is the consistency deviation coefficient of aging between cells, in percentage. If the aging consistency deviation is D% when the SOH is 80%, then when the SOH changes from 100% to 80%, λold changes between 0-D%. This change is affected by the user's working conditions and battery characteristics. It is preferred to perform interpolation processing on this coefficient as the SOH changes. The following mathematical expression can be used:

[0117] λold = 5×D - SOH×D / 20 (4)

[0118] S9, based on the monomer that needs to be balanced, calculate the remaining time for balance:

[0119] Tibal[i] = [SOC(i) – SOC2min– Ctgt–λold]×Ct ×60 / Ibal (5)

[0120] After calculating the remaining time for balancing, balancing is performed according to this time. Similarly, when the BMS is ready to enter sleep mode, this time (i.e., the discharge balancing time) needs to be stored.

[0121] The above calculation is for the remaining time for equalization at the discharge end. If the remaining time for equalization at the charging end already exists in the BMS when calculating the remaining time for equalization at the discharge end, the remaining time for equalization at the charging end will continue to be executed first, and the remaining time for equalization at the discharge end will not be calculated. Figure 6 is a schematic diagram of a strategy of an optional balancing control method provided in an embodiment of the present application, such as Figure 6 As shown, first determine whether it is at the end of charging. If it is at the end of charging, start calculating the remaining equalization time of the charging end, that is, the first equalization time. If it is not at the end of charging, continue to determine whether it is at the end of discharging. If it is at the end of discharging and there is a remaining time for charging equalization, it will continue to perform equalization according to the remaining time for charging end equalization. If it is at the end of discharging, but there is no remaining time for charging equalization, it is determined that the battery pack has not performed charging equalization during this charging and discharging process, then it is allowed to perform the calculation of the remaining time for discharging end equalization.

[0122] The optional implementation method described above achieves at least the following effects: It solves the problem that passive equalization of lithium iron phosphate batteries is difficult to accurately judge and calculate, and proposes a method for calculating the passive equalization time in the non-plateau period. Based on the principle of consistency of the remaining chargeable capacity, it can be triggered at both the charging end and the discharging end, thereby increasing the probability of equalization triggering. During the entire process of charging and discharging, the equalization strategy can accurately reflect the aging differences between cells, avoiding equalization when it is not necessary, thereby improving the performance and efficiency of the lithium iron phosphate battery pack.

[0123] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0124] In this embodiment, a balancing control device is also provided, which is used to implement the above-mentioned embodiments and preferred implementation modes, and the descriptions that have been made will not be repeated. As used below, the terms "module" and "device" can implement a combination of software and / or hardware of a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0125] According to an embodiment of the present application, a device embodiment for implementing the balancing control method is also provided. Figure 7 is a schematic diagram of a balancing control device according to an embodiment of the present application, such as Figure 7 As shown, the above-mentioned balancing control device includes: a data acquisition module 702, a balancing strategy module 704, and the device is described below.

[0126] A data acquisition module 702 is used to acquire recorded data of the battery pack;

[0127] The balancing strategy module 704 is connected to the data acquisition module 702, and is used to complete the charging balancing process of the battery pack according to the unfinished time of the unfinished charging balancing process in the current charging and discharging cycle when the recorded data indicates that the battery pack has not completed the charging balancing process and the battery pack is at the end of the discharge.

[0128] In a balancing control device provided in an embodiment of the present application, a data acquisition module 702 is provided to acquire the recorded data of the battery pack; a balancing strategy module 704 is connected to the data acquisition module 702, and is used to complete the charging balancing process of the battery pack according to the unfinished duration of the unfinished charging balancing process when the recorded data indicates that the battery pack has not completed the charging balancing process in the current charging and discharging cycle, and the battery pack is at the end of the discharge. The purpose of avoiding the mutual interference between the charging balancing and discharging balancing mechanisms is achieved, and the technical effect of improving the battery balancing efficiency is achieved, thereby solving the technical problem of unsatisfactory battery balancing effect in the related technology.

[0129] It should be noted that the above modules can be implemented by software or hardware. For example, for the latter, it can be implemented in the following ways: the above modules can be located in the same processor; or the above modules can be located in different processors in any combination.

[0130] It should be noted that the above data acquisition module 702 and the balancing strategy module 704 correspond to steps S102 to S104 in the embodiment, and the examples and application scenarios implemented by the above modules and the corresponding steps are the same, but are not limited to the contents disclosed in the above embodiments. It should be noted that the above modules can be run in a computer terminal as part of the device.

[0131] It should be noted that the optional or preferred implementation of this embodiment can refer to the relevant description in the embodiment, which will not be repeated here.

[0132] The above-mentioned balancing control device may also include a processor and a memory. The data acquisition module 702, the balancing strategy module 704, etc. are all stored in the memory as program units, and the processor executes the above-mentioned program units stored in the memory to implement corresponding functions.

[0133] The processor includes a kernel, which retrieves the corresponding program unit from the memory. There can be one or more kernels. The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one storage chip.

[0134] An embodiment of the present application provides a non-volatile storage medium on which a program is stored, and when the program is executed by a processor, a balancing control method is implemented.

[0135] The embodiment of the present application provides an electronic device, which includes a processor, a memory, and a program stored in the memory and can be run on the processor. When the processor executes the program, the following steps are implemented: obtaining recorded data of a battery pack; when the recorded data indicates that the battery pack has not completed the charge equalization process in the current charge and discharge cycle, and the battery pack is at the end of discharge, completing the charge equalization process of the battery pack according to the unfinished time of the unfinished charge equalization process. The device in the present application can be a server, a PC, etc.

[0136] The present application also provides a computer program product, which, when executed on a data processing device, is suitable for executing a program that is initialized with the following method steps: obtaining recorded data of a battery pack; when the recorded data indicates that the battery pack has not completed charge equalization processing in the current charge and discharge cycle, and the battery pack is at the end of discharge, completing the charge equalization processing of the battery pack according to the incomplete duration of the incomplete charge equalization processing.

[0137] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0138] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0139] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0140] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0141] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0142] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0143] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0144] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0145] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0146] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. A balancing control method, characterized in that: include: Get the recorded data of the battery pack; When the recorded data indicates that the battery pack has not completed the charge equalization process in the current charge and discharge cycle and the battery pack is at the end of discharge, the charge equalization process of the battery pack is completed according to the unfinished time length of the unfinished charge equalization process.

2. The method according to claim 1, characterized in that The method further comprises: When the recorded data indicates that the battery pack has not performed the charge equalization process in the current charge and discharge cycle, the discharge equalization process is allowed to be performed on the battery pack.

3. The method according to claim 1, characterized in that The method further comprises: Determine the first single-cell state of charge corresponding to each of the plurality of single-cell batteries included in the battery pack according to the predetermined charge and discharge calibration data, wherein the first single-cell state of charge is the state of charge of the corresponding single-cell battery at the end of charging; Determine a first target cell among the plurality of cells that needs to be subjected to the charge equalization process based on a target value of the battery pack and first cell charge states corresponding to the plurality of cells, wherein the target value of the battery pack represents a capacity deviation allowed between the plurality of cells; Determine a first balancing time according to a first single-cell state of charge corresponding to the first target single cell and a first minimum state of charge of the plurality of single-cell batteries at the end of charging; For the first balancing time, the charging balancing process is performed on the first target cell.

4. The method according to claim 3, characterized in that The determining, based on the equalization target value of the battery pack and the first single-cell charge states corresponding to the multiple single-cell batteries, of a first target single-cell battery that needs to be subjected to the charge equalization process includes: Determine a sum of the first minimum state of charge and the balancing target value as a first judgment threshold; A first single-cell battery whose state of charge is greater than the first judgment threshold value is determined as the first target single-cell battery.

5. The method according to claim 3, characterized in that: The method further comprises: Determine a first boundary value of a platform range of the battery pack based on a charging curve of the battery pack, wherein the independent variable of the charging curve is the state of charge, the dependent variable is the cell voltage, the platform range is a state of charge range determined based on a nonlinear change in cell voltage generated by the battery pack, and the first boundary value is a boundary value of the platform range close to a fully charged state of charge; When the first minimum state of charge is less than the first boundary value, the first minimum state of charge is assigned to the first boundary value.

6. The method according to claim 1, characterized in that The method further comprises: In the case where the discharge equalization process is allowed to be performed on the battery pack, determining the second single-cell charge state corresponding to each of the plurality of single-cell batteries included in the battery pack according to the predetermined charge and discharge calibration data, wherein the second single-cell charge state is the charge state of the corresponding single-cell battery at the end of discharge; Determine a second target cell among the plurality of cells that needs to be subjected to the discharge equalization process based on a target value for equalization of the battery pack and the charge states of the second cells respectively corresponding to the plurality of cells, wherein the target value for equalization indicates a capacity deviation allowed between the plurality of cells; Determining a second balancing time according to a second single-cell state of charge corresponding to the second target single-cell and a second minimum state of charge of the plurality of single-cell batteries at the end of discharge; For the second balancing time, the discharge balancing process is performed on the second target cell.

7. The method according to claim 6, characterized in that The step of determining a second target cell among the plurality of cells that needs to be subjected to the discharge equalization process based on the equalization target value of the battery pack and the second cell charge states corresponding to the plurality of cells respectively comprises: determining an aging factor based on a battery health status of the battery pack; determining a sum of the second minimum state of charge, the aging coefficient, and the balancing target value as a second judgment threshold; A second single cell of the plurality of single cells having a state of charge greater than the second judgment threshold is determined as the second target single cell.

8. The method according to any one of claims 3 to 7, characterized in that The charge and discharge calibration data is determined based on the corresponding relationship between battery temperature, charge state, and single cell voltage when the battery pack is in a predetermined battery health state.

9. A balancing control device, characterized in that: include: A data acquisition module, used for acquiring recorded data of the battery pack; The balancing strategy module is used to complete the charging balancing process of the battery group according to the unfinished time length of the unfinished charging balancing process in the current charging and discharging cycle when the recorded data indicates that the battery group has not completed the charging balancing process and the battery group is at the end of the discharge period.

10. A non-volatile storage medium, characterized in that: The non-volatile storage medium stores a plurality of instructions, and the instructions are suitable for being loaded by a processor and executing the balancing control method described in any one of claims 1 to 8.

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