A lithium battery equalization control method and system

Abstract

The application relates to a lithium battery equalization control method and system, the method comprising: acquiring battery parameters of each battery monomer; determining a monomer battery needing equalization and corresponding equalization current according to the battery parameters; judging whether the battery parameters of the monomer battery needing equalization satisfy preset equalization conditions; if the preset equalization conditions are satisfied, performing equalization operation on the monomer battery needing equalization according to the equalization current and real-time current in the battery parameters. The application screens out the monomer battery needing equalization and the equalization current according to the battery parameters of each battery monomer, effectively judges which lithium batteries need equalization and corresponding equalization indexes, and judges whether to perform equalization operation again in combination with the real-time current in the battery parameters, fully considers the situation that the monomer voltage will change and the preset current will change in the equalization process, and makes the lithium system equalization more accurate.

Description

Technical Field

[0001] This invention relates to the field of lithium battery technology, and particularly to a lithium battery equalization control method and system. Background Technology

[0002] Lithium-ion batteries have a limited upper limit on the terminal voltage of a single cell due to factors such as electrode materials and electrolyte composition. In practical applications, multiple cells are typically connected in series or parallel to achieve higher terminal voltages and greater energy. Differences in manufacturing processes and materials among individual cells result in inconsistencies in capacity, terminal voltage, and internal resistance. Over long periods of charging and discharging, this imbalance among the cells in the battery pack leads to a decrease in usable capacity. For example, in a series-connected battery pack, the cell with the lowest capacity determines the total capacity of the pack. In an unbalanced battery pack, during charging, one or more cells will reach their maximum capacity before others. During discharging, cells that are not fully charged will discharge to their limit capacity before others, causing the battery pack to stop supplying power prematurely due to insufficient voltage. Therefore, in the series-parallel connection of battery packs, it is necessary to balance the individual cells within the pack.

[0003] Currently, battery equalization primarily relies on determining the ΔSOC (State of Charge) of individual cells to decide whether equalization is necessary. This method uses a single indicator and is not entirely accurate in assessing the equalization status. Furthermore, existing technologies typically calculate the corresponding capacity difference ΔCAP based on the ΔSOC of each cell, and then calculate the required equalization time T based on the ratio of ΔCAP to a preset current I. This approach maintains a constant equalization time and lacks consideration for the dynamic changes in electrical parameters during the equalization process, resulting in inaccurate control over the equalization duration. Therefore, improving the accuracy of lithium battery equalization control is a pressing issue that needs to be addressed. Summary of the Invention

[0004] In view of this, it is necessary to provide a lithium battery equalization control method and system to overcome the problems of low accuracy in lithium battery equalization judgment and lack of consideration for real-time dynamic parameter changes in the existing technology.

[0005] To address the aforementioned technical problems, this invention provides a lithium battery equalization control method, comprising:

[0006] Obtain the battery parameters of each individual battery cell;

[0007] Based on the battery parameters, determine the individual cells that need to be balanced and the corresponding balancing current;

[0008] Determine whether the battery parameters of the individual cells to be balanced meet the preset balancing conditions.

[0009] If the preset balancing conditions are met, then the balancing operation is performed on the individual cells that need to be balanced based on the current to be balanced and the real-time current in the battery parameters.

[0010] Furthermore, the battery parameters include individual cell voltages, and determining the individual cells requiring balancing and their corresponding balancing currents based on these parameters includes:

[0011] For each individual battery cell, the voltage difference is determined based on the corresponding cell voltage and the minimum voltage, wherein the minimum voltage is the lowest cell voltage among all individual battery cells.

[0012] Determine whether the voltage difference meets the preset voltage condition. If the voltage difference meets the condition, then it belongs to the single cell that needs to be balanced.

[0013] The corresponding current to be balanced is determined based on the individual cell voltage of the cell that needs to be balanced.

[0014] Further, the battery parameters include individual cell voltage, and determining the corresponding balancing current based on the individual cell voltage of the cell to be balanced includes:

[0015] Based on the individual cell voltage of the cells to be balanced, the corresponding SOC value of the cells is retrieved through a preset data table, and the minimum SOC value among all the individual cells to be balanced is determined.

[0016] The corresponding balancing current is determined based on the minimum SOC value and the individual SOC value of the cells to be balanced.

[0017] Furthermore, the battery parameters also include battery health, battery rated capacity, and the call cycle for performing the balancing task. The step of determining the corresponding balancing current based on the minimum SOC value and the individual SOC value of the cells to be balanced includes:

[0018] The SOC difference is determined based on the difference between the minimum SOC value and the SOC value of the individual cell that needs to be balanced.

[0019] The first product value is determined based on the product of the SOC difference, the battery health, and the battery rated capacity.

[0020] The equalization current corresponding to the individual cell that needs to be equalized is determined based on the difference between the first product value and the call cycle.

[0021] Furthermore, the battery parameters include hardware board temperature, cell temperature, and single-cell SOC value. The preset equalization conditions include: the hardware board temperature of the single cell to be equalized meets a first temperature condition, the cell temperature of the single cell to be equalized meets a second temperature condition, and the single-cell SOC value of the single cell to be equalized meets the maximum SOC value condition.

[0022] Furthermore, the battery parameters include individual cell voltages. If the preset balancing conditions are met, then based on the required balancing current and the real-time current in the battery parameters, a balancing operation is performed on the individual cells requiring balancing, including:

[0023] If the preset equalization condition is met, the real-time current is determined based on the individual cell voltage of the cell to be equalized.

[0024] Determine whether the required current and the real-time current meet the preset current conditions;

[0025] If the current condition is met, the equalization current is updated according to the real-time current, and an equalization operation is performed on the individual cells that need to be equalized.

[0026] If the current condition is not met, the equalization operation is terminated.

[0027] Furthermore, the preset current condition includes: the current to be balanced is greater than the real-time current.

[0028] Further, if the current condition is met, then updating the current to be balanced based on the real-time current, and performing a balancing operation on the individual cells to be balanced, includes:

[0029] If the current condition is met, the current to be balanced is subtracted from the real-time current to obtain the updated current to be balanced.

[0030] Based on the updated equalization current, the battery sampling chip is controlled to perform discharge equalization operation on the individual cells that need equalization.

[0031] Furthermore, the method also includes:

[0032] When the balancing operation is interrupted, store the remaining current that needs to be balanced and the cell number of the individual cell that needs to be balanced.

[0033] If the balancing operation is restored within the preset time, then the balancing operation will continue to be performed on the individual cells corresponding to the stored cell serial numbers based on the remaining current to be balanced.

[0034] If the equalization operation is not restored within the preset time, the process returns to the step of obtaining the battery parameters of each individual battery cell.

[0035] The present invention also provides a lithium battery equalization control method, comprising: individual battery cells, a battery sampling chip, and a control chip connected in sequence, wherein the battery sampling chip is used to collect battery parameters of the individual battery cells, and the control chip stores a computer program. When the program is executed, the lithium battery equalization control method described above is implemented based on the individual battery cells and the battery sampling chip.

[0036] Compared with existing technologies, the beneficial effects of this invention include: First, it effectively acquires the battery parameters of each individual battery cell; then, by judging the battery parameters, it filters out the individual cells that need to be balanced and their corresponding balancing currents, ensuring the accuracy of the balancing judgment; further, it further judges whether to perform balancing on the selected individual cells that need to be balanced, ensuring the accuracy of the balancing operation; finally, it combines the real-time current during the balancing process with the dynamic changes caused by the individual cell voltage to control the start and stop of the balancing operation, accurately controlling the accuracy of the balancing operation. In summary, this invention, based on the battery parameters of each individual battery cell, filters out the individual cells that need to be balanced and their corresponding balancing currents, effectively determines which lithium batteries need balancing and their corresponding balancing indicators, and then combines the real-time current in the battery parameters to judge whether to perform the balancing operation, fully considering the situation that the individual cell voltage and the preset current will change during the balancing process, making the lithium battery system balancing more accurate. Attached Figure Description

[0037] Figure 1 A flowchart illustrating an embodiment of the lithium battery equalization control method provided by the present invention;

[0038] Figure 2 Provided by the present invention Figure 1 A flowchart illustrating an embodiment of step S102;

[0039] Figure 3 Provided by the present invention Figure 2 A flowchart illustrating an embodiment of step S203;

[0040] Figure 4 Provided by the present invention Figure 3 A flowchart illustrating an embodiment of step S302;

[0041] Figure 5 Provided by the present invention Figure 1 A flowchart illustrating an embodiment of step S104;

[0042] Figure 6 Provided by the present invention Figure 5 A flowchart illustrating an embodiment of step S503;

[0043] Figure 7 Provided by the present invention Figure 1 A flowchart illustrating the first embodiment following step S104;

[0044] Figure 8 This is a schematic diagram of an embodiment of the lithium battery equalization control system provided by the present invention. Detailed Implementation

[0045] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0046] In the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Furthermore, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0047] In the description of this invention, reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the described embodiments can be combined with other embodiments.

[0048] In the description of this invention, the execution order of the steps between processes is not limited to the order in which they appear in the text. Their order can be adjusted or they can appear in parallel.

[0049] This invention provides a lithium battery equalization control method and system, which combines battery parameters to judge the equalization status and takes into account the real-time current changes caused by changes in individual cell voltage, effectively controlling the execution of equalization operations, and providing a new approach to further improve the accuracy of lithium battery equalization control.

[0050] Before describing the embodiments, the relevant terms are defined as follows:

[0051] Lithium-ion batteries: Lithium-ion batteries are a type of battery that uses lithium metal or lithium alloys as positive / negative electrode materials and a non-aqueous electrolyte solution. The earliest lithium metal battery was proposed and studied by Gilbert N. Lewis in 1912. In the 1970s, MS Whittingham proposed and began researching lithium-ion batteries. Due to the highly reactive chemical properties of lithium metal, its processing, storage, and use require very strict environmental controls. With the development of science and technology, lithium-ion batteries have become mainstream. Lithium-ion batteries can be broadly divided into two categories: lithium metal batteries and lithium-ion batteries. Lithium-ion batteries do not contain metallic lithium and are rechargeable. The fifth generation of rechargeable batteries, the lithium metal battery, was developed in 1996, and its safety, specific capacity, self-discharge rate, and performance-price ratio are superior to lithium-ion batteries. Due to its high technical requirements, only companies in a few countries produce this type of lithium metal battery.

[0052] Battery balancing: Battery balancing is a technique that extends battery life by maximizing the capacity of multiple series-connected batteries to ensure the energy availability of each cell. Battery balancing refers to using differential current on different cells within a battery pack. A battery equalizer is a functional component in a battery management system (BMS) used to perform battery balancing commonly found in lithium-ion electric vehicles and ESS applications. Typically, the cells in a battery pack have different capacities and are at different State of Charge (SOC) levels (SoC refers to the remaining capacity of an individual cell relative to its maximum capacity after charging and discharging). Without redistribution, discharge must stop when the lowest-capacity cell is depleted, even if other cells are not completely discharged, limiting the energy delivery capacity of the battery pack. A balanced battery is one where every cell in a battery pack has the same State of Charge (SoC).

[0053] Based on the above technical terms, existing technologies often fail to accurately determine the balancing process of lithium batteries and do not adequately consider the dynamic changes during the balancing process, resulting in inaccurate execution of the balancing operation. Therefore, this invention aims to propose an accurate lithium battery balancing control method and system.

[0054] The specific embodiments are described in detail below:

[0055] This invention provides a lithium battery equalization control method, combined with Figure 1 Let's take a look. Figure 1 A flowchart illustrating an embodiment of the lithium battery equalization control method provided by the present invention includes steps S101 to S104, wherein:

[0056] In step S101, the battery parameters of each battery cell are obtained;

[0057] In step S102, based on the battery parameters, the individual cells that need to be balanced and the corresponding balancing currents are determined.

[0058] In step S103, it is determined whether the battery parameters of the individual cells to be balanced meet the preset balancing conditions.

[0059] In step S104, if the preset balancing condition is met, then the balancing operation is performed on the individual cells that need to be balanced according to the current to be balanced and the real-time current in the battery parameters.

[0060] In this embodiment of the invention, firstly, the battery parameters of each individual battery cell are effectively acquired; then, by judging the battery parameters, individual battery cells that need to be balanced and their corresponding balancing currents are selected to ensure the accuracy of the balancing situation judgment; furthermore, it is determined whether to perform balancing on the selected individual battery cells that need to be balanced to ensure the accuracy of the balancing operation implementation; finally, by combining the real-time current during the balancing process and considering the dynamic changes caused by the individual cell voltage, the start and stop of the balancing operation are controlled, thus accurately controlling the accuracy of the balancing operation implementation.

[0061] It should be noted that the above battery parameters include, but are not limited to, any one or more of the following: cell voltage, battery health, battery rated capacity, call cycle for performing equalization tasks, hardware board temperature, cell temperature, and cell SOC value, which effectively reflect various characteristics of a single battery cell.

[0062] As a preferred embodiment, combined with Figure 2 Let's take a look. Figure 2 Provided by the present invention Figure 1 A flowchart illustrating an embodiment of step S102 includes steps S201 to S203, wherein:

[0063] In step S201, for each battery cell, the voltage difference is determined based on the corresponding cell voltage and the minimum voltage, wherein the minimum voltage is the lowest cell voltage among all battery cells.

[0064] In step S202, it is determined whether the voltage difference meets the preset voltage condition. If the voltage difference meets the condition, then it belongs to the single cell that needs to be balanced.

[0065] In step S203, the corresponding current to be balanced is determined based on the individual cell voltage of the cell to be balanced.

[0066] In this embodiment of the invention, the individual battery cell is compared with the smallest cell voltage in the whole battery cell system based on the voltage difference, thereby performing effective screening. Then, the required balancing current is determined by the cell voltage of the screened cells that need to be balanced.

[0067] In a specific embodiment of the present invention, at the end of the charge and discharge of a single battery pack, when the single battery is in a static state, generally when the current is less than 0.3A, the difference ΔV between the single battery voltage V of each individual battery and the minimum value Vmin among all the single battery voltages is calculated.

[0068] Specifically, the preset voltage condition includes: the voltage difference is greater than a preset voltage value. The preset voltage value is greater than 15mV. In this embodiment of the invention, the need for battery equalization is determined based on the ΔV (e.g., voltage difference greater than 15mV) of each battery cell, and the cell number requiring equalization and the cell number N with the lowest voltage are recorded.

[0069] As a preferred embodiment, combined with Figure 3 Let's take a look. Figure 3 Provided by the present invention Figure 2 A flowchart illustrating an embodiment of step S203 includes steps S301 to S302, wherein:

[0070] In step S301, based on the individual cell voltage of the individual cells that need to be balanced, the corresponding individual cell SOC value is retrieved through a preset data table, and the minimum SOC value among all the individual cells that need to be balanced is determined.

[0071] In step S302, the corresponding balancing current is determined based on the minimum SOC value and the individual SOC value of the cell to be balanced.

[0072] In this embodiment of the invention, multiple battery parameters are combined to efficiently determine the required equalization current.

[0073] In a more specific embodiment, a preset data table is a SOC-OCV table, used to reflect the mapping relationship between SOC value and cell voltage. In this embodiment of the invention, for batteries that need to be equalized, the cell SOC value is obtained by looking up the SOC-OCV table based on its cell voltage, and the minimum SOCmin of the cell is obtained by using multiple cell SOC values.

[0074] As a preferred embodiment, combined with Figure 4 Let's take a look. Figure 4 Provided by the present invention Figure 3 A flowchart illustrating an embodiment of step S302 includes steps S401 to S402, wherein:

[0075] In step S401, the SOC difference is determined based on the difference between the minimum SOC value and the SOC value of the individual cell to be balanced.

[0076] In step S402, a first product value is determined based on the product of the SOC difference, the battery health, and the battery rated capacity.

[0077] In step S403, the equalization current corresponding to the single cell that needs to be equalized is determined based on the difference between the first product value and the call cycle.

[0078] In this embodiment of the invention, the balancing current is effectively calculated based on the SOC difference, battery health, battery rated capacity, and the balancing task call cycle.

[0079] Specifically, the difference between the SOC value of the battery cell that needs to be balanced and the minimum SOC value of the battery cell, SOCmin, is calculated as ΔSOC, which is the SOC difference.

[0080] Specifically, the balancing current is expressed by the following formula:

[0081] ΔI=ΔSOC*SOH*C / T

[0082] Where SOH is the battery health status, C is the battery rated capacity, and T is the cycle for executing the balancing task.

[0083] In a preferred embodiment, the battery parameters include hardware board temperature, cell temperature, and single-cell SOC value. The preset balancing conditions include: the hardware board temperature of the single cell to be balanced meets a first temperature condition, the cell temperature of the single cell to be balanced meets a second temperature condition, and the single-cell SOC value of the single cell to be balanced meets the maximum SOC value condition.

[0084] In this embodiment of the invention, it is determined whether the hardware board temperature, cell temperature, and single-cell state of charge (SOC) are within the allowable range for equalization. If the equalization conditions are met, the equalization operation is initiated.

[0085] It should be noted that the system balance is achieved by comprehensively judging the battery cell voltage and the cell SOC, and the balance operation continues for a short time after power-off. That is, the cells that need to be balanced are first screened by the cell voltage, and then further judged by the hardware board temperature, cell temperature and cell SOC value to ensure the accuracy of the identification of the cells that need to be balanced.

[0086] Specifically, the first temperature condition includes a hardware board temperature less than or equal to a preset first temperature, wherein the preset first temperature is preferably 85°C.

[0087] Specifically, the second temperature condition includes a cell temperature less than or equal to a preset second temperature, wherein the preset second temperature is preferably 58°C.

[0088] Specifically, the maximum SOC value condition includes the individual cell SOC value of the cell to be balanced being greater than a preset SOC value, wherein the preset SOC value is preferably 20%.

[0089] As a preferred embodiment, combined with Figure 5 Let's take a look. Figure 5 Provided by the present invention Figure 1 A flowchart illustrating an embodiment of step S104 includes steps S501 to S504, wherein:

[0090] In step S501, if the preset equalization condition is met, the real-time current is determined based on the individual cell voltage of the cell to be equalized.

[0091] In step S502, it is determined whether the current to be balanced and the real-time current meet the preset current conditions.

[0092] In step S503, if the current condition is met, the current to be balanced is updated according to the real-time current, and a balancing operation is performed on the individual cells to be balanced.

[0093] In step S504, if the current condition is not met, the equalization operation is terminated.

[0094] In this embodiment of the invention, the individual cell voltage and the preset current will change during the equalization process. Therefore, the equalization operation is turned on or off based on the changing real-time current.

[0095] As a more specific embodiment, in step S501, the voltage of the individual cells that need to be balanced is periodically sampled, and the current for real-time balancing is calculated: I = V / R, where V is the individual cell voltage and R is the resistance value of the balancing resistor.

[0096] In a preferred embodiment, the preset current condition includes: the current to be balanced is greater than the real-time current. In this embodiment of the invention, a reasonable preset current condition is set to effectively determine whether to perform a balancing operation.

[0097] As a preferred embodiment, combined with Figure 6 Let's take a look. Figure 6 Provided by the present invention Figure 5 A flowchart illustrating an embodiment of step S503 includes steps S601 to S602, wherein:

[0098] In step S601, if the current condition is met, the current to be balanced is subtracted from the real-time current to obtain the updated current to be balanced.

[0099] In step S602, based on the updated equalization current, the battery sampling chip is controlled to perform a discharge equalization operation on the individual cells that need equalization.

[0100] In this embodiment of the invention, the current to be balanced is updated in real time by combining a real-time circuit, thereby performing an accurate discharge balancing operation.

[0101] As a more specific embodiment, in step S601, when the total current ΔI to be balanced is greater than the current I to be balanced in real time, the balancing current ΔI is updated to ΔI-I, and the balancing operation continues; otherwise, the balancing operation is stopped.

[0102] As a preferred embodiment, combined with Figure 7 Let's take a look. Figure 7 Provided by the present invention Figure 1 The flowchart of the first embodiment after step S104 includes steps S701 to S703, wherein:

[0103] In step S701, when the balancing operation is interrupted, the remaining current to be balanced and the cell number of the individual cells to be balanced are stored.

[0104] In step S702, if the equalization operation is restored within a preset time, then the equalization operation is continued on the cell corresponding to the stored cell number based on the remaining equalization current.

[0105] In step S703, if the equalization operation is not restored within a preset time, the process returns to the step of obtaining the battery parameters of each battery cell.

[0106] In this embodiment of the invention, when the equalization operation is interrupted, such as when the vehicle is powered off, the unfinished equalization operation continues when the vehicle is powered on again within a short period of time; and when the vehicle is not powered on for a short period of time, the equalization judgment and equalization operation are re-performed.

[0107] The preset time is preferably 3 hours.

[0108] In a specific embodiment of the present invention, when the vehicle is powered off, before the equalization process is completed, the remaining current ΔI to be equalized and the serial number of the battery cell to be equalized are stored in the E2PROM. When the vehicle is powered on again within a preset time (e.g., within 3 hours), the remaining current to be equalized is completed. If the preset time is exceeded, the equalization current is recalculated upon the next power-on.

[0109] This invention also provides a lithium battery equalization control system, combined with Figure 8 Let's take a look. Figure 8The schematic diagram of an embodiment of the lithium battery equalization control system provided by the present invention includes battery cells 101, a battery sampling chip 102, and a control chip 103 connected in sequence. The battery sampling chip 102 is used to collect battery parameters of each battery cell 101. The control chip 103 stores a computer program. When the program is executed, it implements the lithium battery equalization control method as described above based on each battery cell 101 and the battery sampling chip 102.

[0110] It should be noted that the battery sampling chip is preferably an AFE chip, and the AFE chip and the control chip preferably communicate via SPI. The AFE chip periodically collects the voltage of each cell, the minimum cell voltage, and the cell temperature, and sends them to the control chip for processing via SPI communication.

[0111] This invention discloses a lithium battery equalization control method and system. First, the battery parameters of each individual battery cell are effectively acquired. Then, by judging the battery parameters, the individual battery cells that need to be equalized and their corresponding equalization currents are selected to ensure the accuracy of the equalization judgment. Furthermore, it is further determined whether equalization should be performed on the selected individual battery cells to ensure the accuracy of the equalization operation. Finally, by combining the real-time current during the equalization process and considering the dynamic changes caused by the individual cell voltage, the start and stop of the equalization operation are controlled, thus accurately controlling the accuracy of the equalization operation.

[0112] The technical solution of this invention selects individual battery cells and their corresponding currents from the battery parameters of each cell, effectively determining which lithium batteries need balancing and their corresponding balancing indicators. It then combines the real-time current in the battery parameters to determine whether to perform the balancing operation. This fully considers the changes in cell voltage and preset current during the balancing process, making the balancing of the lithium battery system more accurate.

[0113] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A lithium battery equalization control method, characterized in that, include: Obtain the battery parameters of each individual battery cell; Based on the battery parameters, determine the individual cells that need to be balanced and the corresponding balancing current; Determine whether the battery parameters of the individual cells to be balanced meet the preset balancing conditions. If the preset balancing conditions are met, then the balancing operation is performed on the individual cells that need to be balanced according to the current to be balanced and the real-time current in the battery parameters. The battery parameters include the individual cell voltage; determining the corresponding balancing current based on the individual cell voltage of the cells to be balanced includes: Based on the individual cell voltage of the cells to be balanced, the corresponding SOC value of the cells is retrieved through a preset data table, and the minimum SOC value among all the individual cells to be balanced is determined. Based on the minimum SOC value and the SOC value of the individual cells that need to be balanced, determine the corresponding current that needs to be balanced. The battery parameters also include battery health, battery rated capacity, and the call cycle for performing the balancing task; determining the corresponding balancing current based on the minimum SOC value and the individual SOC value of the cells to be balanced includes: The SOC difference is determined based on the difference between the minimum SOC value and the SOC value of the individual cell that needs to be balanced. The first product value is determined based on the product of the SOC difference, the battery health, and the battery rated capacity. The current to be balanced for the individual cell to be balanced is determined based on the ratio of the first product value to the call cycle.

2. The lithium battery equalization control method according to claim 1, characterized in that, The battery parameters include individual cell voltages; determining the individual cells requiring balancing and their corresponding balancing currents based on the battery parameters includes: For each individual battery cell, the voltage difference is determined based on the corresponding cell voltage and the minimum voltage, wherein the minimum voltage is the lowest cell voltage among all individual battery cells. Determine whether the voltage difference meets the preset voltage condition. If the voltage difference meets the condition, then it belongs to the single cell that needs to be balanced. The corresponding current to be balanced is determined based on the individual cell voltage of the cell that needs to be balanced.

3. The lithium battery equalization control method according to claim 1, characterized in that, The battery parameters include hardware board temperature, cell temperature, and single-cell SOC value; the preset equalization conditions include: the hardware board temperature of the single cell to be equalized meets a first temperature condition, the cell temperature of the single cell to be equalized meets a second temperature condition, and the single-cell SOC value of the single cell to be equalized meets the maximum SOC value condition.

4. The lithium battery equalization control method according to claim 1, characterized in that, The battery parameters include individual cell voltages; if the preset balancing conditions are met, then based on the required balancing current and the real-time current in the battery parameters, a balancing operation is performed on the individual cells to be balanced, including: If the preset equalization condition is met, the real-time current is determined based on the individual cell voltage of the cell to be equalized. Determine whether the required current and the real-time current meet the preset current conditions; If the current condition is met, the current to be balanced is updated according to the real-time current, and a balancing operation is performed on the individual cells to be balanced. If the current condition is not met, the equalization operation is terminated.

5. The lithium battery equalization control method according to claim 4, characterized in that, The preset current condition includes: the current to be balanced is greater than the real-time current.

6. The lithium battery equalization control method according to claim 5, characterized in that, If the current condition is met, then based on the real-time current, the current to be balanced is updated, and a balancing operation is performed on the individual cells to be balanced, including: If the current condition is met, the current to be balanced is subtracted from the real-time current to obtain the updated current to be balanced. Based on the updated equalization current, the battery sampling chip is controlled to perform discharge equalization operation on the individual cells that need equalization.

7. The lithium battery equalization control method according to claim 1, characterized in that, The method further includes: When the balancing operation is interrupted, store the remaining current that needs to be balanced and the cell number of the individual cell that needs to be balanced. If the balancing operation is restored within the preset time, then the balancing operation will continue to be performed on the individual cells corresponding to the stored cell serial numbers based on the remaining current to be balanced. If the equalization operation is not restored within the preset time, the process returns to the step of obtaining the battery parameters of each individual battery cell.

8. A lithium battery equalization control system, characterized in that, include: The battery cells, battery sampling chip, and control chip are connected in sequence. The battery sampling chip is used to collect battery parameters of each battery cell. The control chip stores a computer program. When the program is executed, it implements the lithium battery equalization control method according to any one of claims 1 to 7 based on each battery cell and the battery sampling chip.

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