Equalization control methods, battery management systems, storage media and software products

Abstract

This application provides an equalization control method, a battery management system, a storage medium, and a program product. The method includes: determining the state of charge (SOC) of each cell in a battery pack based on SOC parameters; the battery pack has multiple cells connected in series, and the SOC parameters include at least the cell voltage; in response to the SOC of each cell satisfying an equalization condition, determining the cells in the battery pack to be equalized based on the cell voltage; the equalization condition includes at least a change in the SOC of some cells due to motor operation, the motor operation originating from a motor connected to the battery pack; determining the remaining equalization time for the cells to be equalized based on at least one of the SOC parameters and usage state of each cell; the remaining equalization time is used for equalization control of the battery pack. This introduces a response mechanism for changes in the SOC of cells due to motor operation, enabling dynamic identification of changes in cell imbalance caused by motor operation in the battery pack, thereby correcting the remaining equalization time and reducing erroneous equalization.

Description

Technical Field

[0001] This application relates to the field of battery technology, and includes, but is not limited to, an equalization control method, a battery management system, a storage medium, and a program product. Background Technology

[0002] In new energy storage and electric vehicle technologies, the battery pack, as a core component, directly affects the stability and efficiency of the system. To improve the overall lifespan and safety of the battery pack, equalization control technology is widely used in multi-cell structures to reduce inconsistencies between individual cells.

[0003] Related technologies typically determine whether cell balancing is necessary by collecting state parameters such as cell voltage and temperature, and then execute the operation in conjunction with a preset balancing strategy. For example, when the state of charge (SOC) of some cells deviates from a set threshold, a balancing mechanism is triggered to redistribute energy.

[0004] However, the balancing methods in related technologies lack the ability to respond to dynamic load changes and are difficult to accurately identify the cells that truly need balancing under complex operating conditions. This results in unreliable balancing calculation results, and continued execution may lead to problems such as untimely or over-balancing, affecting the overall system efficiency and battery life. Summary of the Invention

[0005] To address the problems existing in related technologies, embodiments of this application provide an equalization control method, a battery management system, a storage medium, and a program product. It introduces a response mechanism of motor operation to changes in the state of charge of battery cells, which can dynamically identify changes in the imbalance of battery cells in the battery pack caused by motor operation, thereby correcting the remaining equalization time and reducing false equalization.

[0006] In a first aspect, this application provides a balancing control method, which includes: in response to a battery pack being powered on, determining the state of charge (SOC) of each cell based on SOC parameters of each cell in the battery pack; the battery pack having multiple cells connected in series, the SOC parameters including at least cell voltage; in response to each cell's SOC satisfying a balancing condition, determining the cell to be balanced in the battery pack based on the cell voltage; the balancing condition including at least some cells' SOC changing with motor operation; the motor operation originating from a motor connected to the battery pack; determining the remaining balancing time of the cell to be balanced based on at least one of the SOC parameters and usage state of each cell; the remaining balancing time being used for balancing control of the battery pack.

[0007] In the above embodiments, the state parameters of each cell determine the state of charge of each cell and determine whether the balancing condition is met. If it is met, the cells in the battery pack that need to be balanced are determined based on the cell voltage. Then, the remaining balancing time is determined through the cell's state parameters and usage status. This introduces a response mechanism for changes in the cell's state of charge caused by motor operation, which can dynamically identify changes in cell imbalance caused by motor operation in the battery pack. This corrects the stored remaining balancing time, reduces overcharging or over-discharging of the battery due to incorrect balancing, improves the accuracy and reliability of balancing control, thereby improving the cell consistency level of the battery system, increasing the usable capacity and lifespan of the battery pack, and enhancing overall safety and operating efficiency.

[0008] In some embodiments, in response to the state of charge of each cell satisfying the balancing condition, the cells to be balanced in the battery pack are determined based on the cell voltage, including: in response to some cells in the battery pack undergoing charging and discharging operations with the operation of the motor, the cell with the lowest cell voltage is determined as the target cell based on the cell voltage of each cell; and the cells in the battery pack other than the target cell are determined as the cells to be balanced.

[0009] In the above embodiments, the cells most in need of balancing can be quickly located, thereby improving balancing efficiency and reducing unnecessary energy consumption and time waste. Simultaneously, by introducing an assessment of the impact of motor operation on the charge and discharge states of the cells, the degree of imbalance between cells can be more accurately determined, improving the targeting and accuracy of the balancing strategy, reducing misjudgments caused by external operations, and thus enhancing the intelligence and adaptability of the battery management system.

[0010] In some embodiments, the state parameters further include the rated capacity of each cell, the health status of each cell, and the cell current of each cell; the balancing control method further includes: in response to the difference between the state of charge of any two cells in the battery pack being greater than a preset threshold, determining the cell with the lowest cell voltage as the target cell; determining the cells in the battery pack other than the target cell as cells to be balanced; correspondingly, determining the remaining balancing time of the cells to be balanced based on at least one of the state parameters and usage status of each cell, including: determining the state of charge difference between each cell to be balanced and the target cell based on the state of charge of the target cell and the cells to be balanced; determining the remaining balancing time of each cell to be balanced based on the state of charge difference, rated capacity, health status, and cell current of each cell to be balanced.

[0011] In the above embodiments, parameters such as the rated capacity, health status and current of the battery cell are comprehensively considered, and the remaining balancing time of the battery cell to be balanced is calculated by combining the state of charge difference, so that the remaining balancing time is closer to the actual needs and the accuracy of balancing control is improved.

[0012] In some embodiments, the usage state includes at least the charging or discharging operation of the battery cell in conjunction with the motor operation; determining the remaining balancing time of the battery cell to be balanced based on at least one of the state parameters and usage states of each battery cell includes: in response to the charging or discharging operation of the target battery cell, determining a first capacity change value of the target battery cell based on the state parameters of the target battery cell; updating the initial remaining balancing time of the battery cell to be balanced based on the initial remaining balancing time of the battery cell to be balanced, the state parameters of the battery cell to be balanced, and the first capacity change value to obtain a first remaining balancing time; the initial remaining balancing time is stored in the battery management system of the battery pack; in response to the charging or discharging operation of the battery cell to be balanced, determining a second capacity change value of the battery cell to be balanced based on the state parameters of the battery cell to be balanced; updating the first remaining balancing time based on the first remaining balancing time of the battery cell to be balanced, the state parameters of the battery cell to be balanced, and the second capacity change value to obtain a second remaining balancing time; and performing non-negative processing on the second remaining balancing time to obtain the remaining balancing time.

[0013] In the above embodiments, the capacity change of the target cell and the cell to be balanced are dynamically calculated through the charging and discharging operations, and the remaining balancing time is updated accordingly. This allows for real-time tracking of energy changes between cells, enabling precise correction of the balancing strategy. Consequently, it improves the control accuracy of cell consistency in multi-cell pack series structures, effectively extending battery life and enhancing system stability.

[0014] In some embodiments, the state parameters include charging / discharging current, start time, and end time; the charging / discharging current is either a charging current or a discharging current; determining the first capacity change value of the target cell based on the state parameters of the target cell includes: calculating the initial capacity change value of the target cell based on the charging / discharging current, start time, and end time of the target cell; and rounding the initial capacity change value up to obtain the first capacity change value.

[0015] In the above embodiments, the capacity change value is processed by rounding up in the battery equalization control. This can prevent the BMS from underestimating the cell capacity change, thereby reducing the risk of over-equalization and helping to ensure that the calculation of the remaining equalization time is safer and more conservative, thus improving the accuracy and safety of equalization decisions.

[0016] In some embodiments, the state parameters further include cell current; updating the initial remaining equalization time based on the initial remaining equalization time of the cell to be equalized, the state parameters of the cell to be equalized, and the first capacity change value to obtain a first remaining equalization time includes: determining a first update time based on the first capacity change value and the cell current; subtracting the initial remaining equalization time and the first update time in response to a charging operation of the target cell to obtain a first remaining equalization time; and adding the initial remaining equalization time and the first update time in response to a discharging operation of the target cell to obtain a first remaining equalization time.

[0017] In the above embodiments, the dynamic capacity change of the target cell during the charging and discharging process is quantitatively evaluated, thereby updating the equalization time, improving the accuracy and reliability of equalization control, and preventing imbalance problems caused by incorrect estimation.

[0018] In some embodiments, the state parameters further include cell current; updating the first remaining equalization time based on the first equalization remaining time of the cell to be equalized, the state parameters of the cell to be equalized, and the second capacity change value to obtain a second remaining equalization time includes: determining a second update time based on the second capacity change value and the cell current; adding the first remaining equalization time and the second update time in response to the charging operation of the cell to be equalized to obtain a second remaining equalization time; and subtracting the first remaining equalization time and the second update time in response to the discharging operation of the cell to be equalized to obtain a second remaining equalization time.

[0019] In the above embodiments, the operation of the target cell and the cell to be balanced is processed independently through two update mechanisms, so that the remaining balancing time can more accurately reflect the actual working conditions and improve the effectiveness of the balancing strategy.

[0020] In some embodiments, the second remaining equalization time is processed to obtain the remaining equalization time, including: determining the shortest target time among the second remaining equalization times of each cell to be equalized; and subtracting the target time from the second remaining equalization time of each cell to be equalized to obtain the remaining equalization time.

[0021] In the above embodiments, by performing non-negative processing on the remaining balancing time of all cells to be balanced, the final remaining balancing time is made reasonable and in line with physical meaning, thereby reducing the occurrence of unreasonable balancing commands.

[0022] In some embodiments, the equalization control method further includes updating the initial equalization remaining time in the battery management system based on the equalization remaining time of each cell.

[0023] In the above embodiments, by continuously updating the remaining balance time stored in the BMS, it is ensured that it is always consistent with the current system state, thereby improving the real-time performance and accuracy of balance control.

[0024] Secondly, embodiments of this application provide a battery management system, comprising: a first determining module, configured to determine the state of charge (SOC) of each cell based on SOC parameters of each cell in a battery pack; the battery pack has multiple cells connected in series, and the SOC parameters include at least the cell voltage; a second determining module, configured to determine the cells to be balanced in the battery pack based on the cell voltage in response to the SOC of each cell satisfying a balancing condition; the balancing condition includes at least the SOC of some cells changing with motor operation; the motor operation originating from a motor connected to the battery pack; and a third determining module, configured to determine the remaining balancing time of the cells to be balanced based on at least one of the SOC parameters and the usage state of each cell; the remaining balancing time is used for balancing control of the battery pack.

[0025] Thirdly, embodiments of this application provide a battery management system, which includes: a memory for storing executable instructions; and a processor for implementing the above-mentioned equalization control method when executing the executable instructions stored in the memory.

[0026] Fourthly, embodiments of this application provide a computer-readable storage medium storing executable instructions, which, when a processor executes the executable instructions, implement the above-mentioned equalization control method.

[0027] Fifthly, embodiments of this application provide a computer program product, which includes executable instructions stored in a computer-readable storage medium; when the processor of the equalization control method reads the executable instructions from the computer-readable storage medium and executes the executable instructions, the above-mentioned equalization control method is implemented.

[0028] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0029] Figure 1 This is an optional flowchart of the equalization control method provided in the embodiments of this application. Figure 1 ;

[0030] Figure 2 This is an optional flowchart of the equalization control method provided in the embodiments of this application. Figure 2 ;

[0031] Figure 3This is an optional flowchart of the equalization control method provided in the embodiments of this application. Figure 3 ;

[0032] Figure 4 This is a schematic diagram of the battery management system provided in an embodiment of this application;

[0033] Figure 5 This is a schematic diagram of a hardware entity of the battery management system in an embodiment of this application. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. The described embodiments should not be regarded as limitations on this application. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0035] In the following description, references to "some embodiments" refer to a subset of all possible embodiments. However, it is understood that "some embodiments" may be the same or different subsets of all possible embodiments and may be combined with each other without conflict. Unless otherwise defined, all technical and scientific terms used in the embodiments of this application have the same meaning as commonly understood by one of ordinary skill in the art to which the embodiments of this application pertain. The terminology used in the embodiments of this application is for the purpose of describing the embodiments of this application only and is not intended to limit the application.

[0036] To avoid the ineffective release of battery capacity in multi-cell battery packs due to inconsistent state of charge (SOC) and self-discharge rates among the cells during manufacturing, a Battery Management System (BMS) can be used for balancing control of the battery pack. Here, battery pack balancing control refers to the process of using specific control strategies and circuit designs to make the charge, voltage, and other states of the multiple cells within the battery pack tend to be consistent. BMS balancing can maximize the minimum cell capacity of the battery pack.

[0037] Currently, in the battery manufacturing process, differences in battery SOC due to process and other factors mainly include two aspects: inconsistencies in the final SOC of the cells and inconsistencies in the self-discharge coefficient of the cells. These differences in final SOC and the resulting variations in self-discharge rates during use affect the overall capacity of the battery. Battery packs incorporating equalization control management can ensure that the SOC of each cell reaches a consistent level.

[0038] In related technologies, for battery structures with multiple cells connected in series, differences in manufacturing processes or self-discharge rates during use often lead to variations in the State of Charge (SOC) between cells. Traditional balancing methods typically calculate based on the state of cells within a single battery pack. However, in multi-cell series systems controlled by a motor, other BMS functions (such as any function that enables energy transfer between cells) perform independent and mutual charging / discharging operations between battery packs, causing changes in the relative voltage relationships between them. Imbalance identification is often based on the voltage distribution of individual cells within the battery. If the balancing algorithms in related technologies are directly applied to battery packs with this structure, the calculated balancing time for each individual cell is unreliable. Continued execution may result in untimely or over-balancing control, impacting overall system efficiency and battery life.

[0039] To alleviate the problems existing in related technologies, the applicant proposes an imbalance identification method for multi-cell battery packs controlled by a motor. The method can identify imbalance based on the battery parameters in the series circuit of the battery pack. If the BMS performs motor operation, it can effectively and accurately identify the impact of the charging and discharging operation performed by the motor between multiple battery packs on the balancing based on the battery parameters, and adaptively correct the remaining balancing time to ensure that the balancing time is reliable in real time, thereby improving the consistency level of the cells in the series-connected battery pack.

[0040] Based on the above considerations, the inventors, through in-depth research, have provided a balancing control method. This method, in response to the battery pack being powered on, determines the state of charge (SOC) of each cell based on its SOC parameters. The battery pack has multiple cells connected in series, and the SOC parameters include at least the cell voltage. In response to each cell's SOC satisfying balancing conditions, the cell to be balanced in the battery pack is determined based on its SOC voltage. The balancing conditions include at least some cells having a SOC that changes with motor operation. The remaining balancing time for the cell to be balanced is determined based on at least one of the cell's SOC parameters and its usage state. This remaining balancing time is used for balancing control of the battery pack.

[0041] Here, the battery cell can also be a battery pack, meaning a battery pack is composed of multiple sub-battery packs connected in series. In this case, balancing is performed on each sub-battery pack, and each sub-battery pack can contain multiple battery cells. The balancing control method can also be based on the state parameters of each sub-battery pack in the battery pack to determine the state of charge (SOC) of each sub-battery pack; the SOC parameters include at least the sub-battery pack voltage; in response to the SOC of each sub-battery pack satisfying the balancing condition, the sub-battery pack to be balanced is determined based on the sub-battery pack voltage; the balancing condition includes at least the SOC of some sub-battery packs changing with motor operation; and the remaining balancing time of the sub-battery pack to be balanced is determined based on at least one of the SOC parameters and usage state of each sub-battery pack. The following embodiment uses a battery pack with multiple battery cells connected in series as an example for explanation.

[0042] Thus, this embodiment of the application determines the state of charge (SOC) of each cell based on its state parameters after the battery pack is powered on, and judges whether the balancing conditions are met. If they are met, the cells in the battery pack that need to be balanced are determined based on their voltage. Then, the remaining balancing time is determined based on the cell's SOC parameters and usage status. This introduces a response mechanism of motor operation to changes in cell SOC, which can dynamically identify changes in cell imbalance caused by motor operation in a multi-cell series system. This corrects the stored remaining balancing time, reduces overcharging or over-discharging due to incorrect balancing, improves the accuracy and reliability of balancing control, thereby improving the cell consistency level of the battery system, increasing the usable capacity and lifespan of the battery pack, and enhancing overall safety and operating efficiency.

[0043] The application of new energy batteries in daily life and industry is becoming increasingly widespread. New energy batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in aerospace and other fields. With the continuous expansion of the application fields of power batteries, the market demand is also constantly increasing. In the embodiments of this application, the battery involved can be a battery cell, also known as a battery unit. A battery cell refers to a basic unit that can realize the mutual conversion of chemical energy and electrical energy, and can be used to make battery modules or battery packs to supply power to electrical devices. A battery cell can be a rechargeable battery, which refers to a battery cell that can be recharged after discharge to activate the active materials and continue to be used. Battery cells can be lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid batteries, etc., and the embodiments of this application are not limited to these.

[0044] In this application embodiment, a battery cell can refer to any shape, such as a square cell or a round cell. A battery cell typically refers to a battery cell, which is one of the basic units constituting a battery. The battery cell is the core component of a battery, responsible for storing and releasing electrical energy. A battery cell can be a lithium-ion battery cell (Li-ion Cell), a lithium-polymer battery cell (Li-polymer Cell), a nickel-metal hydride battery cell (NiMH Cell), etc. This application embodiment does not limit the type of battery cell; it can be selected according to the actual application scenario. In this application embodiment, the battery cell is the core component of a battery pack. A battery pack typically includes multiple battery cells, which are combined together to provide the required electrical capacity and voltage. The components of a battery pack include at least: individual battery cells, a battery management system (BMS), a casing, connecting harnesses, connectors, and interfaces. These components work together to combine the individual battery cells into a fully functional battery pack for various application scenarios. For example, battery packs can be used in electric vehicles, energy storage systems, portable electronic devices, solar energy systems, wind energy systems, emergency backup power supplies, power tools, or electric bicycles, etc. This application does not impose any limitations on these applications; specific applications can be selected based on actual usage scenarios.

[0045] It should be noted that the battery pack can use different types of battery cells, such as lithium-ion batteries, nickel-metal hydride batteries, lithium polymer batteries, etc., depending on the specific application requirements and performance specifications.

[0046] In this embodiment, the battery may also be a single physical module comprising one or more battery cells to provide higher voltage and capacity. When there are multiple battery cells, the multiple battery cells are connected in series, parallel, or mixed via a busbar.

[0047] The following describes an exemplary application of the equalization control method according to embodiments of this application. The equalization control method provided in this application can be executed by the battery management system (BMS) of the battery pack. The technical solution of this application will be described in detail below with reference to the accompanying drawings.

[0048] Figure 1 This is an optional flowchart of the equalization control method provided in the embodiments of this application. Figure 1 ,like Figure 1 As shown, the equalization control method provided in this application embodiment can be implemented through steps S101 to S103:

[0049] Step S101: Determine the state of charge of each cell based on the state parameters of each cell in the battery pack; the battery pack has multiple cells connected in series, and the state parameters include at least the cell voltage.

[0050] In this embodiment, the equalization control method can be applied when the battery pack is powered on. Being powered on means the battery pack is activated and ready for charging and discharging. At this time, the BMS starts working, performing tasks such as self-testing and status monitoring of the battery pack. After the battery pack is powered on, the BMS can collect the status parameters of each cell in real time. These status parameters can include cell voltage, cell current, and cell temperature. The cell voltage reflects the current energy storage level of the cell.

[0051] This application's embodiments determine the state of charge (SOC) of each battery cell by measuring its individual cell voltage. SOC refers to the ratio of the battery's current charge to its rated capacity, and is an important indicator for evaluating the battery's charge / discharge level. For example, in a battery pack consisting of 16 cells connected in series, if the voltage of one cell is significantly lower than the others, it may indicate that the cell's SOC is low, requiring equalization control of the battery pack.

[0052] In this embodiment, the battery pack may be composed of multiple cells connected in series or multiple sub-battery packs connected in series. The equalization control method provided in this embodiment is illustrated by taking the equalization control of multiple cells connected in series in the battery pack as an example.

[0053] In some embodiments, the battery pack may also consist of multiple parallel branches, each of which includes multiple cells connected in series. The equalization control method provided in this application embodiment can perform equalization control on the multiple cells connected in series in each parallel branch. This application embodiment does not limit the connection relationship of the battery pack.

[0054] In some embodiments, the BMS continuously monitors each cell in the battery pack to obtain the latest state parameters and state of charge at any time. Once an abnormal fluctuation in cell voltage or a significant difference from other cells is detected, the BMS triggers further diagnostic mechanisms to confirm whether an imbalance exists.

[0055] Step S102: In response to the state of charge of each cell satisfying the balancing condition, determine the cells to be balanced in the battery pack based on the cell voltage; the balancing condition includes at least the state of charge of some cells changing with motor operation; the motor operation comes from the motor connected to the battery pack.

[0056] In this embodiment of the application, when the BMS detects that the state of charge of some cells meets the balancing condition, it can refer to the condition that triggers the energy transfer operation between cells. For example, the difference in SOC between cells exceeds a preset threshold, or the operation of the motor causes the state of charge of the cells to change. It can be considered that the battery pack has entered a state that requires the balancing operation.

[0057] In some embodiments, motor operation may refer to the charging and discharging operation between multiple battery packs controlled by the BMS, such as one cell charging another cell (e.g., the BMS controls the motor to drive a fan or liquid pump to transfer excess energy from cell A to cell B), or two cells discharging each other. Such operations will change the relative voltage relationship between battery packs, thereby affecting the cell imbalance identification results.

[0058] Because the equilibrium condition depends not only on the state parameters of the battery cells themselves, but also on external factors, especially when the battery pack is connected to a motor and undergoes charging and discharging operations. In this case, the operation of the motor may cause individual cells to undergo charging and discharging operations, or there may be charging and discharging operations between different cells, thereby changing the state of charge distribution of the cells.

[0059] Therefore, in the equalization control method provided in this application embodiment, it is necessary to determine which cells in the battery pack need to be equalized, i.e., the cells to be equalized. For example, if the voltage of a certain cell changes significantly in a short period of time, and this change is closely related to the operation of the motor, then that cell is likely to be the object to be equalized. The BMS can comprehensively determine which cells need to be included in the equalization plan based on the trend of cell voltage changes and the historical records of motor operation, i.e., determine which cells are the cells to be equalized.

[0060] In this embodiment of the application, the cells to be balanced in the battery pack are determined based on the cell voltage. This can be done by identifying the cell with the lowest current cell voltage in the battery pack. Since this cell has the lowest cell voltage, there is no need to balance it. Therefore, the cells in the battery pack other than the cell with the lowest cell voltage can be identified as the cells to be balanced that need to be balanced.

[0061] Here, the BMS monitors the status parameters of each cell in real time. Therefore, the cells to be balanced are continuously updated as the battery pack operates, ensuring that the cells that most need balancing are always selected for processing. At the same time, the BMS also considers the relative positional relationship between the cells to reduce the performance degradation of the entire battery pack caused by local imbalances.

[0062] Step S103: Based on at least one of the state parameters and usage states of each cell, determine the remaining balancing time for the cell to be balanced; the remaining balancing time is used for balancing control of the battery pack.

[0063] Here, usage status can refer to whether the battery cell has undergone charging and discharging operations or whether the battery pack has undergone charging and discharging operations. Based on the usage status, the capacity change of the battery cell that has undergone charging and discharging operations can be determined, thereby determining the remaining equalization time of the battery cell to be equalized.

[0064] The remaining equalization time can refer to the estimated time required for a certain cell to complete the equalization operation. This time can be calculated based on the cell's state parameters (such as voltage, capacity, health status, etc.) or based on the capacity changes during the cell's charging and discharging. Based on this event, the accuracy and real-time performance of equalization control can be ensured.

[0065] In this embodiment, the calculation of the remaining balancing time depends on various factors, including but not limited to the difference in state of charge (SOC) between the cells, the battery's rated capacity, state of health (SOH), and the equivalent balancing current of the balancing circuit. For example, if the SOC difference between two cells is large, it means that more energy needs to be transferred between them to reach equilibrium, thus increasing the remaining balancing time accordingly. On the other hand, if the current of the balancing circuit is large, energy transfer can be completed in a shorter time, thereby shortening the remaining balancing time.

[0066] In some embodiments, the BMS dynamically adjusts the remaining balancing time for each cell by combining real-time collected cell status parameters and usage status. When the BMS performs cross-cell charging and discharging operations, it corrects the remaining balancing time based on the capacity change of each cell. For example, if a cell performs a charging operation during motor operation, the remaining balancing time of its internal cells will decrease; conversely, if a discharging operation is performed, the remaining balancing time will increase. In this way, the BMS can ensure that the remaining balancing time of all cells remains accurate and reliable, thereby improving the overall balancing efficiency.

[0067] After obtaining the remaining balancing time for each cell, the BMS will adjust the charging and discharging of the battery according to the balancing strategy during this period. For example, during charging, the BMS can transfer energy from high-SOC cells to low-SOC cells by controlling the charging current or using active balancing circuitry to achieve balancing. During discharging, the BMS can redistribute the charge from high-SOC cells to low-SOC cells using differential current or active balancing strategies.

[0068] In some embodiments, the balancing operation of a cell is stopped when the remaining balancing time of the cell reaches zero, or the SOC of the cell reaches a preset target value, or a fault that prohibits balancing occurs.

[0069] This embodiment determines the state of charge (SOC) of each cell by using its state parameters and checks whether the balancing conditions are met. If met, it identifies the cells in the battery pack that need balancing based on their voltage. Then, it determines the remaining balancing time based on the cell's SOC and usage status. This introduces a response mechanism for changes in cell SOC caused by motor operation, dynamically identifying changes in cell imbalance caused by motor operation. This corrects the stored remaining balancing time, reducing overcharging or over-discharging due to incorrect balancing, improving the accuracy and reliability of balancing control, thereby enhancing cell consistency in the battery system, increasing the battery pack's usable capacity and lifespan, and improving overall safety and operating efficiency.

[0070] In this embodiment of the application, when balancing multiple cells in a battery pack, it is not necessary to perform balancing control on every single cell when the state of charge of each cell meets the balancing condition. Therefore, it is necessary to determine which cells need to be balanced. Step S102 in the balancing control method provided in this embodiment of the application can be implemented through steps S1021 and S1022:

[0071] Step S1021: In response to the charging and discharging operation of some cells in the battery pack with the operation of the motor, the cell with the lowest cell voltage is determined as the target cell based on the cell voltage of each cell.

[0072] In some embodiments, the charging and discharging of some cells during motor operation can refer to a situation in a multi-cell series structure where the BMS controls the motor to perform independent or mutual charging and discharging operations on different battery packs. This causes some cells to undergo multiple charge-discharge cycles in a short period, affecting the SOC distribution of multiple cells within the battery pack. In electric vehicles, when multiple cells are used for driving or energy recovery during vehicle operation, some cells may be in a state of frequent charging and discharging, while others remain relatively stable. This dynamic change renders the balancing strategy based on static SOC calculation in related technologies inapplicable, easily leading to misbalancing.

[0073] In this embodiment, the cell with the lowest voltage can be identified by comparing the voltages of all cells and marked as the target cell that does not require equalization. Voltage is one of the most direct parameters reflecting the state of charge (SOC) of a cell, especially in lithium iron phosphate (LFP) batteries, where there is a good linear relationship between SOC and voltage. Therefore, the cell with the lowest voltage can be used as the target cell that does not require equalization.

[0074] In some embodiments, the average SOC of each cell can be used as a balancing benchmark to balance all cells in the battery pack.

[0075] Here, when the battery pack consists of multiple sub-cells connected in series, the sub-cell pack containing the cell with the lowest voltage is identified as the target sub-cell pack, and the sub-cell packs outside the target sub-cell pack are identified as the sub-cell packs to be balanced.

[0076] Step S1022: Identify the cells in the battery pack other than the target cell as cells to be balanced.

[0077] In some embodiments, cells in the battery pack other than the target cell can be identified as cells to be balanced. These cells have a higher State of Charge (SOC) or greater energy reserves than the target cell, thus requiring energy transfer to the target cell to achieve balancing. In this way, the BMS can concentrate resources to adjust the remaining cells based on the state of the target cell, ensuring a more consistent energy distribution throughout the battery pack.

[0078] This allows for the rapid identification of the cells most in need of balancing, thereby improving balancing efficiency and reducing unnecessary energy consumption and time waste. Simultaneously, by introducing an assessment of the impact of motor operation on the cell's charge and discharge state, the degree of imbalance between cells can be more accurately determined, improving the targeting and accuracy of the balancing strategy, reducing misjudgments caused by external operations, and thus enhancing the intelligence and adaptability of the battery management system.

[0079] In some embodiments, the state parameters may include the rated capacity of each cell, the health status of each cell, and the cell current of each cell. Here, the state parameters of each cell in the battery pack can be monitored in real time. When the difference between the SOC of any two cells exceeds a preset threshold (e.g., 1%), the previously calculated remaining balancing time of each cell stored in the BMS needs to be updated. Therefore, the balancing control method provided in this application embodiment further includes step S1:

[0080] S1. In response to the difference between the states of charge of any two cells in the battery pack being greater than a preset threshold, the cell with the lowest cell voltage is identified as the target cell, and the cells in the battery pack other than the target cell are identified as cells to be balanced.

[0081] In this embodiment, when the SOC difference between any two cells in the battery pack exceeds a preset threshold, it indicates a significant energy inconsistency between the cells within the battery pack, which will affect the overall performance and lifespan of the battery system. The preset threshold can be set according to the battery type, system design, and safety standards; for example, it can be set to 1% or higher, with the specific value determined by the actual application scenario.

[0082] In this case, the cell with the lowest cell voltage can be identified as the target cell, and the cells in the battery pack other than the target cell can be identified as cells to be balanced.

[0083] Here, when the battery pack consists of multiple sub-battery packs connected in series, if the difference between the states of charge of any two cells is greater than a preset threshold, the sub-battery pack containing the cell with the lowest voltage is identified as the target sub-battery pack, and the sub-battery packs in the battery pack other than the target sub-battery pack are identified as the sub-battery packs to be balanced.

[0084] Correspondingly, step S103 can be achieved through steps S1031 to S1032:

[0085] Step S1031: Based on the state of charge of the target cell and the cell to be balanced, determine the state of charge difference between each cell to be balanced and the target cell among the multiple cells.

[0086] In this embodiment, the state-of-charge (SOC) difference reflects the degree of difference between the SOC of each cell to be balanced and the target cell, and is an important basis for determining how to perform balancing. The larger the difference, the worse the consistency between the cells. In a multi-cell pack series system, the independent charging and discharging operations under motor control may cause changes in the SOC distribution of cells in different battery packs. Therefore, it is necessary to dynamically calculate the SOC difference to ensure the accuracy of the balancing strategy.

[0087] The embodiments of this application can accurately assess the SOC deviation between each cell to be balanced and the target cell by calculating the state of charge difference, providing basic data for the calculation of the remaining balancing time.

[0088] Step S1032: Based on the difference in state of charge, rated capacity, health status and cell current of each cell to be balanced, determine the remaining balancing time for each cell to be balanced.

[0089] In this embodiment, the remaining balancing time refers to the estimated time required to complete the cell balancing operation, which is the result of comprehensive calculation based on multiple cell state parameters. In addition to the state of charge difference, this embodiment also considers the cell's rated capacity (i.e., the maximum amount of energy the cell can store), the state of health (SOH) reflecting the degree of cell aging, and the cell current (which affects the charging / discharging rate). These factors together determine the time required for the cell to reach balancing.

[0090] Here, the higher the rated capacity of the battery cell, the more electricity it stores, and the longer the balancing time may be; the lower the health status, the less the actual usable capacity of the battery cell, which may lead to a decrease in balancing efficiency; and the battery cell current directly affects the speed of energy transfer per unit time, thus affecting the speed of the balancing process.

[0091] In some embodiments, the remaining balancing time H for each cell to be balanced can be achieved by formula (1):

[0092] (1);

[0093] in, The SOC difference between each cell to be balanced and the target cell; C is the rated capacity of each cell to be balanced; SOH is the state of health of the battery pack. The cell current of each cell to be balanced can be the equivalent balancing current of the branch where each cell to be balanced is located.

[0094] Here, the equivalent equalization current can be obtained by monitoring the BMS. If the equivalent equalization current is large, it indicates that the power flow is fast, and the equalization time may be shortened accordingly.

[0095] After calculating the remaining balancing time for each cell to be balanced, the remaining balancing time can be stored in the BMS, and the previously stored remaining balancing time in the BMS can be updated and overwritten.

[0096] This application embodiment comprehensively considers parameters such as the rated capacity, health status, and current of the battery cell, and calculates the remaining balancing time of the battery cell to be balanced by combining the state of charge difference, so that the remaining balancing time is closer to the actual needs and the accuracy of balancing control is improved.

[0097] Figure 2 This is an optional flowchart of the equalization control method provided in the embodiments of this application. Figure 2 ,like Figure 2 As shown, step S103 in the equalization control method provided in this application embodiment can also be implemented by steps S201 to S205:

[0098] Step S201: In response to the target cell performing a charging or discharging operation, determine the first capacity change value of the target cell based on the state parameters of the target cell.

[0099] In some embodiments, the first capacity change value refers to the amount of capacity change of the target cell calculated based on its current and charging / discharging time and other state parameters during the charging and discharging operation, reflecting the degree to which the cell actually participates in energy exchange during this period.

[0100] Step S201 can be achieved through steps S2011 and S2012:

[0101] Step S2011: Calculate the initial capacity change of the target cell based on the charging and discharging current, start time, and end time of the target cell.

[0102] In some embodiments, the state parameters include the charge / discharge current I, the start time t1, and the end time t2; the charge / discharge current is either the charging current or the discharging current. The state parameters can refer to the magnitude of the current passing through the battery cell during the battery charge / discharge process, or the current of each cell to be balanced collected by a current sensor. The charge / discharge current can be constant or a pulsed current that varies with time, depending on the battery pack's charging strategy and load requirements.

[0103] Here, the start time refers to the specific moment when the target cell begins to perform a charging and discharging operation, while the end time refers to the moment when the cell completes the charging and discharging operation. These two time points together constitute a complete charging and discharging cycle, which is used to calculate the capacity change.

[0104] By collecting the charging and discharging current and combining it with its start and end times, the total energy input or output of the battery cell during this period can be calculated, thus obtaining the initial capacity change value. This process can be achieved through integration, that is, integrating the curve of the charging and discharging current changing with time to obtain the total change in energy. Here, the first capacity change value ΔCap of the target battery cell can be obtained through formula (2):

[0105] (2);

[0106] Here, the initial capacity change of the target cell is calculated based on the charging and discharging current, start time, and end time. This accurately reflects the actual capacity fluctuation of the cell within a specific time period, thus providing a reliable basis for subsequent equalization control.

[0107] Step S2012: Round the initial capacity change value up to obtain the first capacity change value.

[0108] Here, rounding up converts a decimal number to its nearest integer that is not less than that decimal. For example, if the initial capacity change is 1.2 Ah, then rounding up will result in 2 Ah. This can reduce the accumulation of errors that may be caused by rounding and can be used in battery management systems where conservative estimates of capacity changes are required.

[0109] In battery balancing control, using the round-up method to process capacity change values ​​can prevent the BMS from underestimating cell capacity changes, thereby reducing the risk of over-balancing. This helps to ensure that the calculation of the remaining balancing time is safer and more conservative, thus improving the accuracy and safety of balancing decisions.

[0110] Step S202: Based on the initial remaining equalization time of the cell to be equalized, the state parameters of the cell to be equalized, and the first capacity change value, update the initial remaining equalization time to obtain the first remaining equalization time; the initial remaining equalization time is stored in the battery management system of the battery pack.

[0111] In some embodiments, the initial equalization remaining time may refer to data stored in the BMS of the battery pack, or data calculated when the equalization condition was last triggered.

[0112] The first remaining equalization time refers to the dynamically corrected result based on the initial remaining equalization time, combined with the current state parameters of the target cell and the first capacity change value. This parameter reflects the time required for the cell to complete the equalization operation under the current conditions.

[0113] In some embodiments, the state parameters may include the cell current; step S202 can be implemented through steps S2021 and S2023:

[0114] Step S2021: Determine the first update time based on the first capacity change value and the cell current.

[0115] Here, the first capacity change value refers to the change in cell capacity caused by current flow during the charging and discharging operation of a multi-battery pack controlled by a motor. This change value can be obtained through integration calculation, representing the total amount of electricity flowing into or out of the cell per unit time, and is used to measure the degree of impact of the current operation on the cell's state of charge (SOC).

[0116] Cell current can be the real-time current value flowing through the cell, and its magnitude and direction determine whether the cell is in a charging or discharging state. Cell current can be collected by a current sensor and transmitted to the BMS for processing.

[0117] By combining the initial capacity change value with the cell current, a time correction factor Δcap / I, i.e., the first update time, can be calculated. This time reflects the time required for the capacity change under the current, thus providing basic data support for adjusting the remaining equalization time. For example, at a certain moment, if the cell current is 5A and the capacity change value is 0.5Ah, then the first update time is 0.1 hours.

[0118] Step S2022: In response to the charging operation of the target cell, subtract the initial equalization remaining time and the first update time to obtain the first equalization remaining time.

[0119] In some embodiments, when the target cell is charging, it means that the SOC of the target cell is increasing, and the gap between the target cell and the balancing target is narrowing. To reflect this change, the initial balancing remaining time can be reduced by the corresponding first update time to more accurately reflect the remaining balancing time required for the current cell to reach a balanced state.

[0120] At this point, the remaining time H1 of the first equilibrium can be achieved using formula (3):

[0121] (3);

[0122] in, The remaining time for initial equilibrium.

[0123] In other words, after the BMS detects that the target battery cell is charging, it will automatically trigger the time update logic, subtracting the first update time from the initial remaining equalization time to obtain the updated first remaining equalization time. For example, if the initial remaining equalization time is 2 hours and the first update time is 0.1 hours, then the updated time is 1.9 hours.

[0124] Step S2023: In response to the discharge operation of the target cell, the initial equalization remaining time and the first update time are added together to obtain the first equalization remaining time.

[0125] In some embodiments, when the target cell is in a discharging state, the SOC decreases, and the gap between it and the equilibrium target widens. Therefore, it is necessary to extend its equilibrium remaining time to compensate for the SOC deviation caused by the discharge. At this time, the first update time can be added to the initial equilibrium remaining time to reflect the increase in time between the current cell and the equilibrium state. At this time, the first equilibrium remaining time H1 can also be realized by formula (4):

[0126] (4);

[0127] If the initial equilibrium remaining time is 2 hours and the first update time is 0.1 hours, then the updated time will be 2.1 hours.

[0128] This application embodiment quantifies and evaluates the dynamic capacity change of the target cell during the charging and discharging process, thereby updating the equalization time, improving the accuracy and reliability of equalization control, and preventing imbalance problems caused by incorrect estimation.

[0129] Step S203: In response to the charging or discharging operation of the cell to be balanced, determine the second capacity change value of the cell to be balanced based on the state parameters of the cell to be balanced.

[0130] In some embodiments, the second capacity change value refers to the amount of change in charge calculated based on the voltage, current, temperature and other state parameters of the cell to be balanced when it performs a charging and discharging operation.

[0131] In some embodiments, the second capacity change value can also be calculated using formula (2), which will not be elaborated here.

[0132] Step S204: Based on the first remaining equalization time of the cell to be equalized, the state parameters of the cell to be equalized, and the second capacity change value, update the first remaining equalization time to obtain the second remaining equalization time.

[0133] Here, the second remaining equalization time refers to the estimated time after further correction based on the first remaining equalization time, taking into account the state parameters of the cell to be equalized and the second capacity change value. This further considers the impact of energy changes in the cell during charging and discharging on its equalization requirements during motor operation, making the equalization time closer to actual operating conditions.

[0134] In some embodiments, step S204 can be implemented by steps S2041 and S2043:

[0135] Step S2041: Determine the second update time based on the second capacity change value and the cell current.

[0136] Here, the second capacity change value can be calculated using the same method as the first capacity change value; that is, the second update time can be Δcap. i / I i , where i is the i-th cell to be balanced.

[0137] Step S2042: In response to the charging operation of the cell to be balanced, the first remaining equalization time and the second update time are added together to obtain the second remaining equalization time.

[0138] In some embodiments, when the cell to be balanced is charging, its State of Charge (SOC) increases, which means that the originally expected balancing time will be extended. Therefore, in this case, adding the remaining first balancing time to the second update time can reflect the impact of the SOC increase caused by the charging operation on the balancing time required.

[0139] At this point, the remaining time H2 of the second equilibrium can be achieved using formula (5):

[0140] (5);

[0141] Step S2043: In response to the discharge operation of the cell to be balanced, the first remaining equalization time and the second update time are subtracted to obtain the second remaining equalization time.

[0142] When the cell to be balanced is in a discharging state, its State of Charge (SOC) decreases, which means that the originally expected balancing time will be shortened. Therefore, in this case, subtracting the remaining first balancing time from the second update time can reflect the impact of the SOC decrease caused by the discharge operation on the balancing time required.

[0143] At this point, the second equilibrium remaining time H2 can also be achieved using formula (6):

[0144] (6);

[0145] Step S205: Perform non-negative processing on the second equilibrium remaining time to obtain the equilibrium remaining time.

[0146] In this embodiment of the application, since the target cell and the cell to be balanced may become negative when calculating the remaining balance time due to motor operation, it is necessary to process the second remaining balance time of the cell to be balanced to be non-negative.

[0147] Non-negative processing can be performed by subtracting the minimum remaining second equalization time from the remaining second equalization time of each cell to be equalized. At this time, the minimum remaining equalization time becomes 0, and the remaining equalization time of the other cells to be equalized represents how much more equalization time is needed relative to the cell that was equalized first.

[0148] In some embodiments, step S205 can be implemented by steps S2051 and S2052:

[0149] Step S2051: Determine the target time with the shortest time among the remaining second equalization time of each cell to be equalized.

[0150] In some embodiments, the target time can be the minimum value among the remaining second balancing times of all cells to be balanced, taken as the reference time. By selecting the shortest time as a reference, it can be ensured that the remaining balancing times of all cells are non-negative after processing, reducing the possibility of negative values ​​causing system misjudgment or calculation abnormalities.

[0151] In practical applications, after the battery management system collects the remaining time for the second equalization of multiple cells, it compares them and finds the smallest time as the basis for subsequent calculations. For example, in a battery pack containing 10 cells, if the remaining time for the second equalization of each cell is 5 hours, 7 hours, 6 hours, 8 hours, etc., then the target time should be 5 hours. This standardizes the starting point for the equalization time, thereby simplifying the subsequent equalization control logic and improving the stability and reliability of the system.

[0152] Step S2052: Subtract the target time from the second balancing remaining time of each cell to be balanced to obtain the balancing remaining time.

[0153] After determining the target time, the second remaining balancing time for each cell to be balanced is subtracted from the target time to obtain the final remaining balancing time. This ensures that the remaining balancing time for all cells is greater than or equal to zero.

[0154] For example, if the second remaining time for balancing a certain cell is 7 hours, and the target time is 5 hours, then its final remaining time for balancing will be 2 hours. This ensures that the remaining times for balancing all cells are comparable and that negative values ​​do not affect the system's judgment. It allows all cells to have remaining times for balancing on the same order of magnitude without altering the original data trend, facilitating the system's subsequent balancing strategy formulation and execution.

[0155] In this embodiment, the shortest target time is determined from the second remaining equalization time of each cell to be equalized, and the remaining equalization time of each cell is subtracted from the target time to obtain the remaining equalization time. This eliminates the negative value problem caused by initial differences, thereby achieving standardized equalization time processing and improving the battery management system's accuracy and control efficiency in identifying cell consistency in a multi-cell pack series structure.

[0156] This application embodiment dynamically calculates the capacity change of the target cell and the cell to be balanced by the charging and discharging operations, and updates the remaining balancing time accordingly. This allows for real-time tracking of energy changes between cells, enabling precise correction of the balancing strategy. Consequently, it improves the control accuracy of cell consistency in multi-cell pack series structures, effectively extending battery life and enhancing system stability.

[0157] In some embodiments, the equalization control method further includes step S10:

[0158] Step S10: Update the initial balance remaining time in the battery management system based on the balance remaining time of each cell.

[0159] In multi-cell series systems, the Battery Management System (BMS) may control motors to perform charging and discharging operations between cells, which alters the voltage relationships between cells and affects the accuracy of the remaining equalization time. Therefore, the initial remaining equalization time stored in the BMS must be dynamically updated based on the latest cell state parameters to ensure the effectiveness and reliability of the equalization strategy. For example, if a cell in a battery pack experiences a change in SOC due to charging and discharging operations of other battery packs at a certain moment, the remaining equalization time for each cell in that battery pack must be recalculated, and the equalization schedule for the entire system updated accordingly. This update mechanism reduces false equalization and improves the overall consistency of the battery pack.

[0160] In this embodiment, the initial remaining equalization time in the battery management system is updated based on the remaining equalization time of each cell. This allows for real-time correction of the impact of inter-pack charging and discharging operations caused by motor control on the equalization time, thereby improving the accuracy and reliability of the remaining equalization time, and ultimately enhancing the consistency and overall performance of the battery pack.

[0161] The following will describe an exemplary application of the embodiments of this application in a real-world application scenario.

[0162] This application provides a method for identifying the imbalance in a multi-battery pack series system controlled by a motor. The imbalance calculation can be based on the battery parameters (i.e., state parameters) of the cells in the branch and the changes in the relative voltage relationship of the multiple battery packs after the BMS performs motor operation. This method can effectively identify and correct the remaining equalization time (i.e., the initial remaining equalization time) stored in the BMS, ensuring that the stored remaining equalization time is reliable in real time. The BMS performs equalization operation according to this time.

[0163] This solution monitors battery parameters (voltage, current, temperature, etc.) in real time during motor operation, converts them into their impact on balancing time, and adaptively corrects the stored remaining balancing time based on the voltage distribution throughout the branch, ensuring that the remaining balancing time stored in the BMS is real-time and reliable.

[0164] The method provided in this application embodiment can be applied to the balancing strategy of a battery management system with multiple battery packs connected in series under motor control. It can improve the overall performance and reliability of the battery pack, effectively prevent vehicle performance degradation caused by low cell consistency, effectively prevent breakdowns, and ensure the stable operation of electric vehicles and driver safety.

[0165] For multi-battery pack series systems controlled by a motor, the imbalance identification algorithm in related technologies is not reliable because the BMS performs independent charging and discharging operations on each battery pack due to other functions. This may lead to incorrect balancing decisions.

[0166] This application proposes a method for identifying the imbalance in a multi-battery pack series system controlled by a motor. Figure 3 This is an optional flowchart of the equalization control method provided in the embodiments of this application. Figure 3 ,like Figure 3 As shown, the equalization control method can be implemented through steps S301 to S309:

[0167] S301, Is the battery pack powered off?

[0168] The equalization control method provided in this application embodiment is applied when the battery is powered on. When the battery is powered off, the scheme of this application is not executed. If the battery pack is powered on, step S302 is executed.

[0169] S302: Monitor the status of the battery pack and obtain the status parameters of each cell.

[0170] In some embodiments, the BMS can monitor the status parameters of each cell in the battery pack within the entire series branch in real time, such as the voltage, current, and temperature of each cell.

[0171] S303, Whether to trigger load balancing calculation.

[0172] Here, when the difference in SOC between any two cells in the battery pack is greater than 1%, the battery pack is considered to have triggered an equalization calculation, that is, the unbalancedness calculation condition is met, and step S304 is executed; otherwise, the process ends.

[0173] S304. Determine the minimum voltage cell and the remaining equalization time for each cell.

[0174] In some embodiments, the SOC difference between the minimum voltage cell and the minimum voltage cell (i.e., the target cell) and each cell (i.e., the cell to be balanced) can be determined based on the state parameters of each cell in the entire series branch, and converted into the remaining balancing time for each cell. Both can be stored in the BMS.

[0175] Here, the formula for the remaining balancing time can be: Remaining balancing time = SOC difference * Rated capacity * SOH / Equivalent balancing current. Wherein, SOC difference is the aforementioned state of charge difference; SOH is the aforementioned state of health; and equivalent balancing current is the aforementioned cell current.

[0176] S305, Whether to perform motor operation.

[0177] In some embodiments, when the BMS controls the motor to perform independent / mutual charging and discharging operations between multiple battery packs (i.e., multiple cells or multiple sub-packs), equalization control of the battery packs is required.

[0178] S306. Determine the minimum voltage cell in the battery pack.

[0179] The minimum voltage cell (i.e., target cell or target sub-cell) in the battery pack is determined based on the state parameters. The remaining cell balancing time in the battery pack (i.e., target cell or target sub-cell) containing the minimum voltage cell remains unchanged.

[0180] S307. Calculate the capacity change of the battery cell based on the motor behavior.

[0181] The current collected during the charging and discharging operation can be recorded as the integral of the current flowing into / out of each battery pack (i.e., cell or sub-pack) i with time, i.e., the capacity change value ΔCap_i (i is the serial number of the battery pack (i.e., cell or sub-pack)).

[0182] It's important to note that the capacity change value should be rounded up. This prevents over-balancing when adjusting for remaining equalization time. The rounded-up capacity change value will be slightly larger than the actual calculated value. By allowing a safety margin when adjusting for remaining equalization time, over-balancing can be effectively prevented, thus reducing unnecessary damage to the battery and ensuring its performance and lifespan remain unaffected.

[0183] S308. Calculate the remaining time for equilibrium based on the capacity change value.

[0184] Step (1): If the battery pack containing the lowest voltage cell performs a charging operation during this process, the remaining balancing time of the cells in battery pack i containing non-lowest voltage cells is updated as follows: Updated remaining balancing time_a = Remaining remaining balancing time before update - ΔCap_i / Equivalent balancing current. Wherein, the remaining remaining balancing time before update is the initial remaining balancing time stored in the BMS.

[0185] If the battery pack containing the lowest voltage cell performs a discharge operation during this process, the remaining equalization time of the cells in the battery pack i containing the non-lowest cell voltage is updated as follows: Updated remaining equalization time_a = Unupdated remaining equalization time + ΔCap_i / Equivalent equalization current.

[0186] Step (2): For the other battery packs i containing non-minimum cell voltages, charging or discharging operations were also performed. After the above steps were completed, battery pack i was corrected a second time. If battery pack i performed a charging operation during this process, the difference between it and the minimum cell voltage would increase. In this case, the remaining equalization time of the cells in battery pack i would be updated as follows: Updated remaining equalization time_b = Previous remaining equalization time_a + ΔCap_i / Equivalent equalization current.

[0187] If battery pack i performs a discharge operation during this process, the remaining equalization time of the cells in battery pack i is updated as follows: Updated remaining equalization time_b = Previous remaining equalization time_a - ΔCap_i / Equivalent equalization current.

[0188] The remaining equalization time for all cells is processed to be non-negative. The remaining equalization time BalTime_j for each cell (j is the cell number) is: BalTime_j = updated remaining equalization time_b – minimum remaining equalization time in the branch.

[0189] S309. Update the remaining balance time stored in the BMS.

[0190] The system monitors the status parameters of each cell in the entire branch (such as voltage, current, temperature, etc.) in real time to determine whether to update the remaining equalization time or whether motor operation has been performed. The system repeats the above steps to update the remaining equalization time stored in the BMS.

[0191] By using the above methods, the battery management system can achieve more accurate SOC consistency, thereby improving the overall performance and lifespan of the battery pack. It effectively solves the balancing problem caused by the BMS performing motor functions in multi-battery pack structures, and improves the performance and stability of the battery pack.

[0192] This application introduces an imbalance identification method for a multi-battery pack series system controlled by a motor. Regardless of how the multiple battery packs are charged and discharged, the reliability of the stored balancing time will not be affected, thereby improving the accuracy and reliability of the balancing results. This significantly improves the overall balance of the cells in such battery packs, making the performance of the battery packs more consistent, and thus enhancing the stability and efficiency of the entire battery system.

[0193] The method for evaluating and correcting the impact of voltage distribution changes between battery packs on equalization provided in this application embodiment can effectively and accurately identify the impact of charging and discharging operations performed by the motor between multiple battery packs on equalization based on battery parameters, and adaptively correct the remaining equalization time. This ensures the robustness and reliability of the unbalance identification algorithm and prevents the overall battery performance and lifespan from being reduced due to erroneous equalization.

[0194] Figure 4 This is a schematic diagram of the battery management system provided in an embodiment of this application, as shown below. Figure 4 As shown, the battery management system may include a first determining module 401, a second determining module 402, and a third determining module 403. The first determining module 401 is used to determine the state of charge (SOC) of each cell in the battery pack based on the SOC parameters of each cell. The battery pack has multiple cells connected in series, and the SOC parameters include at least the cell voltage. The second determining module 402 is used to determine the cells in the battery pack to be balanced based on the cell voltage in response to the SOC of each cell satisfying a balancing condition. The balancing condition includes at least the SOC of some cells changing with motor operation. The motor operation originates from a motor connected to the battery pack. The third determining module 403 is used to determine the remaining balancing time of the cell to be balanced based on at least one of the SOC parameters and the usage state of each cell. The remaining balancing time is used for balancing control of the battery pack.

[0195] In some embodiments, the second determining module 402 is further configured to, in response to a portion of the cells in the battery pack undergoing charging and discharging operations with the operation of the motor, determine the cell with the lowest cell voltage as the target cell based on the cell voltage of each cell; and determine the cells in the battery pack other than the target cell as cells to be balanced.

[0196] In some embodiments, the state parameters further include the rated capacity of each cell, the health status of each cell, and the cell current of each cell; the battery management system further includes: a fourth determining module, configured to determine the cell with the lowest cell voltage as the target cell and the cells in the battery pack other than the target cell as cells to be balanced in response to the difference between the states of charge of any two cells in the battery pack being greater than a preset threshold; correspondingly, the third determining module 403 is further configured to determine the state of charge difference between each cell to be balanced and the target cell based on the state of charge of the target cell and the cells to be balanced; and to determine the remaining balancing time of each cell to be balanced based on the state of charge difference, rated capacity, health status, and cell current of each cell to be balanced.

[0197] In some embodiments, the usage state includes at least the charging or discharging operation of the battery cell in conjunction with the motor operation; the third determining module is further configured to, in response to the charging or discharging operation of the target battery cell, determine a first capacity change value of the target battery cell based on the state parameters of the target battery cell; update the initial remaining equalization time based on the initial equalization time remaining of the battery cell to be equalized, the state parameters of the battery cell to be equalized, and the first capacity change value to obtain a first remaining equalization time; the initial remaining equalization time is stored in the battery management system of the battery pack; in response to the charging or discharging operation of the battery cell to be equalized, determine a second capacity change value of the battery cell to be equalized based on the state parameters of the battery cell to be equalized; update the first remaining equalization time based on the first remaining equalization time of the battery cell to be equalized, the state parameters of the battery cell to be equalized, and the second capacity change value to obtain a second remaining equalization time; and perform non-negative processing on the second remaining equalization time to obtain the remaining equalization time.

[0198] In some embodiments, the state parameters include charging and discharging current, start time, and end time; the charging and discharging current is either a charging current or a discharging current; the third determining module is further configured to calculate the initial capacity change value of the target cell based on the charging and discharging current, start time, and end time of the target cell; and round up the initial capacity change value to obtain the first capacity change value.

[0199] In some embodiments, the state parameters further include cell current; the third determining module is further configured to determine a first update time based on the first capacity change value and the cell current; in response to the target cell performing a charging operation, subtract the initial equalization remaining time and the first update time to obtain the first equalization remaining time; in response to the target cell performing a discharging operation, add the initial equalization remaining time and the first update time to obtain the first equalization remaining time.

[0200] In some embodiments, the state parameters further include cell current; the third determining module is further configured to determine a second update time based on the second capacity change value and the cell current; in response to the charging operation of the cell to be balanced, add the first remaining equalization time and the second update time to obtain the second remaining equalization time; in response to the discharging operation of the cell to be balanced, subtract the first remaining equalization time and the second update time to obtain the second remaining equalization time.

[0201] In some embodiments, the third determining module is further configured to determine the shortest target time among the second remaining equalization time of each cell to be equalized; and to subtract the target time from the second remaining equalization time of each cell to be equalized to obtain the remaining equalization time.

[0202] In some embodiments, the battery management system further includes an update module for updating the initial equalization remaining time in the battery management system based on the equalization remaining time of each cell.

[0203] It should be noted that the description of the device embodiments in this application is similar to the description of the method embodiments described above, and has similar beneficial effects as the method embodiments; therefore, it will not be repeated. For technical details not disclosed in the device embodiments, please refer to the description of the method embodiments in this application for understanding.

[0204] It should be noted that, in the embodiments of this application, if the above-mentioned equalization control method is implemented in the form of a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the embodiments of this application, or the part that contributes to the related technology, can be embodied in the form of a software product. This software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, mobile hard drives, read-only memory (ROM), magnetic disks, or optical disks. Thus, the embodiments of this application are not limited to any specific hardware, software, or firmware, or any combination of hardware, software, and firmware.

[0205] This application provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements some or all of the steps in the above-described method. The computer-readable storage medium can be transient or non-transient.

[0206] This application provides a computer program including computer-readable code. When the computer-readable code is run in a computer device, the processor in the computer device performs some or all of the steps in the above-described method.

[0207] This application provides a computer program product, which includes a non-transitory computer-readable storage medium storing a computer program. When the computer program is read and executed by a computer, it implements some or all of the steps in the above-described method. This computer program product can be implemented specifically through hardware, software, or a combination thereof. In some embodiments, the computer program product is specifically embodied as a computer storage medium; in other embodiments, the computer program product is specifically embodied as a software product, such as a software development kit (SDK), etc.

[0208] It should be noted that the descriptions of the various embodiments above tend to emphasize the differences between them, while their similarities or commonalities can be referred to interchangeably. The descriptions of the above embodiments of the device, storage medium, computer program, and computer program product are similar to the descriptions of the above method embodiments and have similar beneficial effects. For technical details not disclosed in the embodiments of the device, storage medium, computer program, and computer program product of this application, please refer to the descriptions of the method embodiments of this application for understanding.

[0209] Figure 5 This is a schematic diagram of a hardware entity of the battery management system in an embodiment of this application, such as... Figure 5 As shown, the hardware entity of the battery management system 500 includes: a processor 501, a communication interface 502, and a memory 503, wherein:

[0210] The processor 501 typically controls the overall operation of the battery management system 500, which may implement the equalization control method provided in the embodiments of this application.

[0211] Communication interface 502 enables computer devices to communicate with other terminals or servers via a network.

[0212] The memory 503 is configured to store instructions and applications executable by the processor 501, and can also cache data to be processed or already processed (e.g., image data, audio data, voice communication data, and video communication data) in the processor 501 and various modules in the battery management system 500. It can be implemented using flash memory or random access memory (RAM). Data transfer between the processor 501, the communication interface 502, and the memory 503 can be performed via bus 504.

[0213] The aforementioned processor can be at least one of the following: Application Specific Integrated Circuit (ASIC), Digital Signal Processor (DSP), Digital Signal Processing Device (DSPD), Programmable Logic Device (PLD), Field Programmable Gate Array (FPGA), Central Processing Unit (CPU), Controller, Microcontroller, and Microprocessor. It is understood that other electronic devices can also implement the functions of the aforementioned processor, and this application does not specifically limit the specific implementation.

[0214] The aforementioned computer storage media / memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic random access memory (FRAM), flash memory, magnetic surface memory, optical disc, or compact disc read-only memory (CD-ROM), etc.; or it can be various terminals that include one or any combination of the above-mentioned memories, such as mobile phones, computers, tablet devices, personal digital assistants, etc.

[0215] It should be understood that the phrase "one embodiment" or "an embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. It should be understood that in the various embodiments of this application, the sequence numbers of the above steps / processes do not imply a sequential order of execution; the execution order of each step / process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application. The sequence numbers of the above embodiments of this application are merely descriptive and do not represent the superiority or inferiority of the embodiments.

[0216] This application uses terms such as "upper," "lower," "top," "bottom," "front," "back," "inner," and "outer" to indicate orientation or positional relationships. This is only for the convenience of describing this application and is not intended to indicate or imply that the device referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the scope of protection of this application.

[0217] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application depending on the specific circumstances.

[0218] It should be noted that, in this application, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0219] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods, such as: multiple units or components may be combined, or integrated into another system, or some features may be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the various components shown or discussed may be through some interfaces, and the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0220] The units described above as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; they may be located in one place or distributed across multiple network units; some or all of the units may be selected to achieve the purpose of this embodiment according to actual needs. Furthermore, the functional units in the embodiments of this application may all be integrated into one processing unit, or each unit may be a separate unit, or two or more units may be integrated into one unit; the integrated unit may be implemented in hardware or in a combination of hardware and software functional units.

[0221] The above are merely embodiments of this application and are not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, and improvements made within the spirit and scope of this application are included within the scope of protection of this application.

Claims

1. An equalization control method, characterized in that, The equilibrium control method includes: The state of charge of each cell is determined based on the state parameters of each cell in the battery pack; the battery pack has multiple cells connected in series, and the state parameters include at least the cell voltage. In response to the state of charge of each cell satisfying the balancing condition, the cells to be balanced in the battery pack are determined based on the cell voltage; the balancing condition includes at least some cells whose state of charge changes with motor operation; the motor operation comes from the motor connected to the battery pack. Based on the state parameters of each cell and the charging and discharging usage status of each cell, the remaining balancing time of the cell to be balanced is determined; the remaining balancing time is used to perform balancing control on the battery pack.

2. The equalization control method according to claim 1, characterized in that, The process of determining the cells to be balanced in the battery pack based on the cell voltage in response to the state of charge of each cell satisfying the balancing condition includes: In response to the charging and discharging operation of some cells in the battery pack in conjunction with the operation of the motor, the cell with the lowest cell voltage is determined as the target cell based on the cell voltage of each cell. The cells in the battery pack other than the target cell are identified as the cells to be balanced.

3. The equalization control method according to claim 1, characterized in that, The status parameters also include the rated capacity of each cell, the health status of each cell, and the cell current of each cell; the equalization control method further includes: In response to the difference between the states of charge of any two cells in the battery pack being greater than a preset threshold, the cell with the lowest cell voltage is identified as the target cell, and the cells in the battery pack other than the target cell are identified as the cells to be balanced. Correspondingly, determining the remaining balancing time of the cell to be balanced based on the state parameters of each cell and the charging / discharging usage status of each cell includes: Based on the state of charge of the target cell and the cell to be balanced, the state of charge difference between each cell to be balanced and the target cell is determined. Based on the difference in state of charge, rated capacity, health status, and cell current of each cell to be balanced, the remaining balancing time for each cell is determined.

4. The equalization control method according to claim 2, characterized in that, The charging and discharging usage state includes at least the charging or discharging operation of the battery cell during the operation of the motor; determining the remaining balancing time of the battery cell to be balanced based on the state parameters of each battery cell and the charging and discharging usage state of each battery cell includes: In response to the target battery cell performing a charging or discharging operation, a first capacity change value of the target battery cell is determined based on the state parameters of the target battery cell; Based on the initial remaining time for balancing the cell to be balanced, the state parameters of the cell to be balanced, and the first capacity change value, the initial remaining time for balancing is updated to obtain the first remaining time for balancing; the initial remaining time for balancing is stored in the battery management system of the battery pack. In response to the charging or discharging operation of the cell to be balanced, a second capacity change value of the cell to be balanced is determined based on the state parameters of the cell to be balanced. Based on the first remaining time of equalization of the cell to be equalized, the state parameters of the cell to be equalized, and the second capacity change value, the first remaining time of equalization is updated to obtain the second remaining time of equalization. The second equilibrium remaining time is processed to be non-negative to obtain the equilibrium remaining time.

5. The equalization control method according to claim 4, characterized in that, The status parameters include charging / discharging current, start time, and end time; the charging / discharging current is either the charging current or the discharging current. Determining the first capacity change value of the target battery cell based on its state parameters includes: Based on the charging and discharging current, start time, and end time of the target battery cell, calculate the initial capacity change value of the target battery cell; The initial capacity change value is rounded up to obtain the first capacity change value.

6. The equalization control method according to claim 4, characterized in that, The status parameters also include the cell current; The step of updating the initial remaining balance time based on the initial remaining balance time of the cell to be balanced, the state parameters of the cell to be balanced, and the first capacity change value to obtain the first remaining balance time includes: The first update time is determined based on the first capacity change value and the cell current; In response to the charging operation of the target battery cell, the initial equalization remaining time and the first update time are subtracted to obtain the first equalization remaining time; In response to the target cell performing a discharge operation, the initial equalization remaining time and the first update time are added together to obtain the first equalization remaining time.

7. The equalization control method according to claim 4, characterized in that, The status parameters also include the cell current; The step of updating the first remaining time of equalization based on the first remaining time of equalization of the cell to be equalized, the state parameters of the cell to be equalized, and the second capacity change value to obtain the second remaining time of equalization includes: The second update time is determined based on the second capacity change value and the cell current; In response to the charging operation of the cell to be balanced, the first remaining balancing time and the second update time are added together to obtain the second remaining balancing time. In response to the discharge operation of the cell to be balanced, the first remaining balance time and the second update time are subtracted to obtain the second remaining balance time.

8. The equalization control method according to claim 4, characterized in that, The step of performing non-negative processing on the second equilibrium remaining time to obtain the equilibrium remaining time includes: In the remaining time of the second equalization of each cell to be equalized, determine the target time with the shortest time. The remaining time for equalization of each cell to be equalized is subtracted from the target time to obtain the remaining time for equalization.

9. The equalization control method according to any one of claims 4 to 8, characterized in that, The equalization control method further includes: The initial remaining equalization time in the battery management system is updated based on the remaining equalization time of each cell.

10. A battery management system, characterized in that, The battery management system includes: The first determining module is used to determine the state of charge of each cell based on the state parameters of each cell in the battery pack; the battery pack has multiple cells connected in series, and the state parameters include at least the cell voltage; The second determining module is used to determine the cells to be balanced in the battery pack based on the cell voltage in response to the state of charge of each cell satisfying the balancing condition; the balancing condition includes at least the state of charge of some cells changing with motor operation. The third determining module is used to determine the remaining balancing time of the cell to be balanced based on the state parameters of each cell and the charging and discharging usage status of each cell; the remaining balancing time is used to perform balancing control on the battery pack.

11. A battery management system, characterized in that, The battery management system includes: A memory for storing executable instructions; a processor for implementing the equalization control method according to any one of claims 1 to 9 when executing the executable instructions stored in the memory.

12. A computer-readable storage medium, characterized in that, The device stores executable instructions for causing a processor to execute the executable instructions to implement the equalization control method according to any one of claims 1 to 9.

13. A computer program product, characterized in that, The computer program product includes executable instructions stored in a computer-readable storage medium; When the processor of the battery management system reads the executable instructions from the computer-readable storage medium and executes the executable instructions, it implements the equalization control method according to any one of claims 1 to 9.

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