Battery equalization control methods, electronic devices and their storage media

Abstract

This invention discloses a battery equalization control method, an electronic device, and its storage medium. The method includes: determining the voltage range of the lowest single-cell voltage in a battery pack, where each pre-set voltage range corresponds to an equalization trigger condition and an equalization time ratio; determining whether each battery in the battery pack meets the first equalization trigger condition; when the number of batteries to be equalized is greater than a preset number, or when there are batteries with adjacent serial numbers, alternatingly allocating the batteries to be equalized according to their serial numbers, dividing them into two groups; and equalizing the two groups of batteries to be equalized sequentially according to the preset equalization time and the equalization time ratio of the first equalization trigger condition. This invention can address the wide voltage range characteristics of sodium-ion batteries by achieving differentiated equalization triggering through multi-segment voltage division, effectively reducing equalization temperature rise and improving equalization efficiency through time-sharing group equalization and dynamic time ratio control, and exhibits good hardware compatibility.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of battery balancing, and in particular to a battery balancing control method, an electronic device and its storage medium. Background Technology

[0002] With the rapid development of new energy technologies, sodium-ion batteries have seen rapid development and widespread application in energy storage and low-speed electric vehicles due to their significant advantages such as low cost and abundant resources. As an important supplement to lithium-ion batteries, sodium-ion batteries have shown promising development prospects in large-scale energy storage applications.

[0003] However, the electrochemical characteristics of sodium-ion batteries differ significantly from those of lithium-ion batteries, posing new challenges to the design of battery management systems. First, sodium-ion batteries exhibit complex voltage characteristics, with a wide operating voltage range, typically between 1.5V and 3.95V, and significant differences in the slope of the capacity-voltage curves across different voltage segments. For example, the slope in the low-voltage segment is approximately 0.15V / %SOC, while the slope in the high-voltage segment is only about 0.03V / %SOC. This difference makes traditional balancing strategies based on a single voltage threshold difficult to apply to sodium-ion battery systems.

[0004] Secondly, sodium-ion batteries exhibit significant polarization during charging and discharging, especially at high voltages (above 3.8V). Due to the decreased migration rate of sodium ions, the polarization voltage increases significantly, leading to increased errors in SOC estimation. Simultaneously, the passive balancing current increases linearly with voltage, reaching high levels at high voltages; for example, it can reach 132mA under a 30Ω resistance, causing a temperature rise exceeding 50°C.

[0005] In addition, sodium-ion batteries have a steep voltage change region (1.5V-2.8V) in the low-voltage range. The voltage-capacity relationship in this region exhibits nonlinear characteristics. The traditional ampere-hour integration method can have an estimation error of up to 8% in this region, which requires correction by combining a piecewise linearization model. This further increases the complexity of SOC estimation.

[0006] Existing battery balancing technologies have several shortcomings when applied to sodium-ion batteries. Traditional single-segment balancing strategies rely solely on voltage difference as a trigger condition, failing to fully consider the unique characteristics of sodium-ion batteries at different voltage ranges, and are prone to misjudgment or missed judgment. For example, a voltage difference of 200mV in the low-voltage range may only be caused by a 5% difference in SOC, but traditional methods struggle to distinguish between a sudden voltage change and a true battery imbalance state.

[0007] Meanwhile, existing technologies have significant shortcomings in thermal management. Passive equalization current increases linearly with voltage, and continuous discharge at high voltage levels can lead to excessive current and rapid temperature rise. Traditional fixed-time equalization strategies do not take into account the differences in equalization current across different voltage levels, lack effective group control and heat dissipation design, and when multiple battery cells are equalized simultaneously, heat accumulation can easily occur, posing a threat to system safety. Summary of the Invention

[0008] The main technical problem solved by the embodiments of the present invention is to provide a battery equalization control method, an electronic device and its storage medium, which can solve at least some of the defects of the existing battery equalization methods.

[0009] In a first aspect, embodiments of the present invention provide a battery balancing control method, comprising: determining the voltage segment where the lowest single-cell voltage in a battery pack is located; each pre-set voltage segment corresponds to an balancing trigger condition and an balancing time ratio; determining whether each battery in the battery pack satisfies a first balancing trigger condition; the first balancing trigger condition is the balancing trigger condition of the voltage segment where the lowest single-cell voltage is located; when the number of batteries to be balanced is greater than a preset number, or when there are batteries with adjacent serial numbers to be balanced, the batteries to be balanced are alternately allocated according to their serial numbers, dividing the batteries to be balanced into two groups; the batteries to be balanced are those that satisfy the first balancing trigger condition; and balancing the two groups of batteries to be balanced sequentially according to a preset balancing time and the balancing time ratio of the first balancing trigger condition; the balancing time ratio is the ratio of balancing time to heat dissipation time.

[0010] Optionally, the pre-defined voltage segments include: monitoring the voltage change and the change in remaining battery capacity (or state of charge); dividing the battery voltage range into several voltage segments based on the ratio of the voltage change to the change in remaining battery capacity (or state of charge); setting corresponding equalization trigger conditions for the several voltage segments; obtaining corresponding equalization current ranges based on the several voltage segments; and setting equalization time ratios for the corresponding several voltage segments based on the equalization current ranges.

[0011] Optionally, determining the voltage range where the minimum single-cell voltage in the battery pack is located includes: acquiring the single-cell voltage of each battery in the battery pack; determining the minimum single-cell voltage among the single-cell voltages; and determining the voltage range where the minimum single-cell voltage is located.

[0012] Optionally, determining whether each battery in the battery pack meets the first equalization trigger condition includes: sampling and acquiring the individual cell voltage of each battery in the battery pack; calculating the voltage difference between the individual cell voltage of each battery and the minimum individual cell voltage; determining whether the voltage difference is greater than a preset voltage difference; if so, the corresponding battery meets the first equalization trigger condition.

[0013] Optionally, determining whether each battery in the battery pack meets the first equalization trigger condition includes: sampling and acquiring the remaining capacity of each battery in the battery pack; determining the minimum remaining capacity of each battery; calculating the difference between the remaining capacity of each battery and the minimum remaining capacity; determining whether the difference in remaining capacity is greater than a preset capacity difference; if so, the corresponding battery meets the first equalization trigger condition; or determining whether each battery in the battery pack meets the first equalization trigger condition includes: sampling and acquiring the state of charge (SOC) of each battery in the battery pack; determining the minimum SOC of each battery; calculating the difference between the SOC of each battery and the minimum SOC; determining whether the SOC difference is greater than a preset SOC difference; if so, the corresponding battery meets the first equalization trigger condition.

[0014] Optionally, when the number of batteries to be balanced is greater than a preset number, or when there are batteries with adjacent serial numbers, the batteries to be balanced are alternately allocated according to their serial numbers to divide them into two groups. This includes: recording the serial numbers of the batteries to be balanced; determining whether the number of batteries to be balanced is greater than the preset number; the preset number is half the number of strings in the battery group; if not, determining whether there are batteries with adjacent serial numbers; if the number of batteries to be balanced is greater than the preset number, or when there are batteries with adjacent serial numbers, the batteries to be balanced are alternately allocated according to their serial numbers from smallest to largest to divide them into a first battery group and a second battery group.

[0015] Optionally, the step of balancing the two battery packs to be balanced sequentially according to the ratio of the preset balancing time to the balancing time of the first balancing trigger condition includes: obtaining a first heat dissipation time according to the ratio of the preset balancing time to the balancing time of the first balancing trigger condition; and balancing the first battery pack to be balanced and the second battery pack to be balanced sequentially according to the preset balancing time and the first heat dissipation time.

[0016] Optionally, the method further includes: obtaining the remaining capacity difference of each battery to be balanced based on the remaining capacity (state of charge) of each battery to be balanced and the remaining capacity threshold (state of charge threshold) corresponding to the first equalization trigger condition; obtaining the maximum remaining capacity difference of the two groups of batteries to be balanced respectively; obtaining the corresponding single discharge amount based on the preset equalization time and the voltage range of the lowest voltage cell; and obtaining the total equalization time based on the preset equalization time, the maximum remaining capacity difference, the corresponding single discharge amount, and the equalization time ratio of the first equalization trigger condition.

[0017] In a second aspect, embodiments of the present invention provide an electronic device, comprising: at least one processor; at least one network interface communicatively connected to a corresponding processor; and a memory communicatively connected to the at least one processor; wherein the network interface is used to establish a communication connection between the processor and other external devices; the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the battery equalization control method as described in the first aspect.

[0018] Thirdly, embodiments of the present invention provide a non-volatile computer storage medium storing computer-executable instructions, which are executed by one or more processors to cause the one or more processors to perform the battery equalization control method as described in the first aspect.

[0019] The beneficial effects of the embodiments of the present invention are as follows: Unlike the prior art, the embodiments of the present invention can achieve differentiated equalization triggering by dividing the voltage into multiple segments to take into account the wide voltage range characteristics of sodium-ion batteries. By using time-division group equalization and dynamic time ratio control, the equalization temperature rise can be effectively reduced and the equalization efficiency can be improved. It also has good hardware compatibility. Attached Figure Description

[0020] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0021] Figure 1 This is a schematic flowchart of a battery balancing control method provided by an embodiment of the present invention;

[0022] Figure 2 This is a flowchart illustrating the pre-set voltage segment provided in an embodiment of the present invention;

[0023] Figure 3 yes Figure 1A schematic diagram of the sub-process of step S100 shown;

[0024] Figure 4 yes Figure 1 A schematic diagram of a sub-process of step S200 is shown below;

[0025] Figure 5 yes Figure 1 Another sub-process diagram of step S200 shown;

[0026] Figure 6 yes Figure 1 A schematic diagram of the sub-process of step S300 is shown;

[0027] Figure 7 yes Figure 1 A schematic diagram of the sub-process of step S400 is shown;

[0028] Figure 8 This is a schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. Detailed Implementation

[0029] To facilitate understanding of this application, a more detailed description is provided below with reference to the accompanying drawings and specific embodiments. It should be noted that when an element is described as being "fixed to" another element, it can be directly on the other element, or one or more intermediate elements may exist between them. When an element is described as being "connected" to another element, it can be directly connected to the other element, or one or more intermediate elements may exist between them. The terms "upper," "lower," "inner," "outer," "bottom," etc., used in this specification indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0031] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0032] The technical solutions in this application will be described below with reference to the accompanying drawings.

[0033] In some embodiments of this application, a battery balancing control method is provided, applied to a sodium-ion battery management system, the flowchart of which is shown below. Figure 1 As shown, the specific steps include the following:

[0034] Step S100: Determine the voltage range where the lowest single cell voltage in the battery pack is located.

[0035] It should be noted that sodium-ion batteries have a wide voltage range, with an operating voltage range of 1.5V to 3.95V, and the electrochemical characteristics differ significantly across different voltage ranges. In some embodiments of this application, the pre-setting of voltage segments is based on the ratio of voltage change to the change in remaining battery capacity, forming several voltage segments. Each voltage segment corresponds to a specific equalization trigger condition and equalization time ratio. It is understood that the state of charge (SOC) is the percentage of remaining capacity to the current maximum usable capacity. The current maximum usable capacity is related to factors such as cycle count and temperature. All battery cells are assumed to be under the same temperature and cycle count; therefore, the pre-setting of voltage segments can also be based on the ratio of voltage change to the change in SOC.

[0036] Specifically, the battery pack comprises multiple individual cells. The voltage values ​​of each individual cell are sampled to determine the minimum individual cell voltage. As an example, and not a limitation, when the battery pack contains n individual cells, the minimum individual cell voltage V_cellMin is determined by comparing the individual cell voltages V_cell(1), V_cell(2), to V_cell(n). Specifically, based on the value of the minimum individual cell voltage, its voltage range is determined, thereby determining the equalization triggering conditions and equalization time ratio required for subsequent equalization operations.

[0037] Step S200: Determine whether each battery in the battery pack meets the first equalization trigger condition.

[0038] It should be noted that the first equalization trigger condition is the equalization trigger condition corresponding to the voltage range where the minimum cell voltage is located. Specifically, it is determined whether the corresponding trigger condition threshold is met by calculating the voltage difference between each cell and the minimum cell voltage, or the remaining capacity difference between each cell and the minimum remaining capacity, or the state of charge difference between each cell and the minimum state of charge.

[0039] In some embodiments of this application, the determination of the equalization trigger condition is based on the voltage difference, the remaining capacity difference, or the state of charge difference. By way of example and not limitation, when the voltage difference of a single cell is greater than a preset voltage difference, or when the remaining capacity difference of a single cell is greater than a preset remaining capacity difference, or when the state of charge difference of a single cell is greater than a preset state of charge difference, that single cell is considered to meet the first equalization trigger condition and becomes a cell to be equalized.

[0040] Step S300: When the number of batteries to be balanced is greater than the preset number, or when there are batteries with adjacent serial numbers, the batteries to be balanced are alternately distributed according to their serial numbers to divide them into two groups.

[0041] Specifically, when the number of batteries to be balanced exceeds a preset number, or when there are batteries with adjacent serial numbers, they need to be alternately allocated according to their serial numbers to divide them into two groups. As an example and not a limitation, the preset number is half the number of battery strings. By alternately allocating serial numbers, it is ensured that adjacent batteries are not in the same group and are not balanced simultaneously.

[0042] In some embodiments of this application, the grouping algorithm allocates batteries alternately based on their serial numbers. Specifically, the batteries to be balanced are sequentially assigned to the first and second battery groups in ascending order of serial number. It should be noted that by allocating batteries alternately by serial number, simultaneous balancing operations on adjacent batteries can be avoided, thereby preventing excessive local temperature rise and current superposition problems.

[0043] Step S400: Equalize the two battery packs to be equalized in sequence according to the preset equalization time and the equalization time ratio of the first equalization trigger condition.

[0044] It should be noted that the equalization time ratio is the ratio of equalization time to heat dissipation time, and different equalization time ratios correspond to different voltage ranges. By controlling the ratio of equalization time to heat dissipation time, temperature rise can be effectively controlled while ensuring equalization efficiency.

[0045] In some embodiments of this application, the balancing operation is performed in a time-division grouping manner. As an example and not a limitation, the first battery pack to be balanced is balanced first, and then the second battery pack to be balanced is balanced after the first is completed. Specifically, each group of balancing operations is performed according to a corresponding balancing time ratio, that is, charging and discharging operations are performed according to a preset balancing time, and then cooling and waiting are performed according to a corresponding cooling time.

[0046] The voltage segmentation fully considers the differences in electrochemical characteristics of sodium-ion batteries at different voltage ranges. Specifically, different voltage segments correspond to different equalization trigger conditions and equalization time ratios, thereby achieving targeted equalization control strategies. The group equalization strategy effectively avoids the adverse effects caused by simultaneous equalization of adjacent cells through alternating allocation. Specifically, by controlling the grouping and equalization sequence of the cells to be equalized, both equalization efficiency and system safety and stability are ensured.

[0047] In some embodiments of this application, the pre-setting of the voltage section specifically includes the following steps, the flowchart of which is shown below. Figure 2 As shown:

[0048] Step S111: Monitor the changes in battery voltage and remaining battery capacity (or state of charge).

[0049] Sodium-ion batteries exhibit different voltage-remaining capacity (state of charge) characteristic curves within different voltage ranges. Accurate electrochemical characteristic data can be obtained by continuously monitoring the voltage change ΔV and the change in remaining capacity (state of charge change ΔSOC). Specifically, the voltage change is obtained by real-time sampling of the voltage of individual cells, and the change in remaining capacity (or state of charge change) is calculated by measuring the current and integrating it over time.

[0050] In some embodiments of this application, the monitoring of voltage changes and changes in remaining battery capacity (or state of charge) covers the entire operating voltage range of the sodium-ion battery. By way of example and not limitation, the operating voltage range of the sodium-ion battery is 1.5V to 3.95V, within which the voltage-state of charge relationship exhibits significant differences across different voltage segments. Specifically, the slope of the steep voltage change region in the low-voltage segment is approximately 0.15V / %SOC, the slope of the linear capacity region in the medium-voltage segment is approximately 0.08V / %SOC, and the slope of the significant polarization region in the high-voltage segment is approximately 0.03V / %SOC.

[0051] Step S112: Divide the battery voltage range into several voltage segments based on the ratio of the voltage change to the change in remaining battery capacity (change in state of charge).

[0052] It's easy to understand that the ratio of voltage change to battery remaining capacity change (change in state of charge) reflects the slope of the voltage-remaining capacity (state of charge) curve, with different slope ranges corresponding to different electrochemical characteristics. As an example, not a limitation, we can determine the boundaries of voltage ranges by analyzing the distribution characteristics of the ratio of voltage change to battery remaining capacity change (change in state of charge). Specifically, when the ratio is around 0.15V / %SOC, it corresponds to the steep voltage change region in the low-voltage segment (1.5V-2.8V); when the ratio is around 0.08V / %SOC, it corresponds to the linear SOC region in the medium-voltage segment (2.8V-3.8V); and when the ratio is around 0.03V / %SOC, it corresponds to the significant polarization region in the high-voltage segment (3.8V-3.95V).

[0053] In some embodiments of this application, the voltage range division fully considers the differences in electrochemical characteristics of sodium-ion batteries. As an example, and not a limitation, the low-voltage range (1.5V-2.8V) exhibits a steep voltage change region with significant polarization effects and sensitivity to voltage difference changes; the medium-voltage range (2.8V-3.8V) exhibits a linear SOC region, where the voltage-SOC relationship is relatively stable; and the high-voltage range (3.8V-3.95V) exhibits a region of significant polarization, requiring precise control to avoid overcharging risks. Defining the ranges based on these characteristic differences ensures the relative consistency of electrochemical characteristics within each range.

[0054] Step S113: Set corresponding equalization trigger conditions for several voltage sections.

[0055] Different voltage ranges require differentiated equalization triggering conditions to suit their electrochemical characteristics. As an example, and not a limitation, the low-voltage range (1.5V-2.8V) has relatively lenient triggering conditions due to its steep voltage change characteristics: ΔV(i)>50mV or ΔSOC(i)>5%; the medium-voltage range (2.8V-3.8V) uses a combined determination method: ΔV(i)>30mV or ΔSOC(i)>2%; and the high-voltage range (3.8V-3.95V) uses strict combined conditions: ΔV(i)>10mV and ΔSOC(i)>0.5%.

[0056] In some embodiments of this application, the setting of the equalization triggering condition is based on specific electrochemical characteristic analysis. As an example and not a limitation, in the low-voltage segment, the voltage difference ΔV = 200mV may only be caused by the SOC difference (in reality, only ΔSOC = 5%), so a relaxed threshold strategy is adopted to avoid misjudgment. Specifically, if the voltage of battery No. 3 in the battery pack is 2.5V and the voltage of battery No. 6 is 2.3V (where No. 6 is the smallest single cell voltage), then ΔV(3) = 200mV > 50mV, which meets the low-voltage segment triggering condition, and battery No. 3 needs to be equalized.

[0057] Step S114: Obtain the corresponding balanced current range based on several voltage segments.

[0058] Specifically, the formula for calculating the balancing current is I(i) = V_cell(i) / R, where R is the balancing resistance value. In this embodiment, the balancing resistance value is set to 30Ω. It is easy to understand that different voltage ranges correspond to different balancing current ranges: the low-voltage range (1.5V-2.8V) corresponds to a current range of approximately 50mA-93mA; the medium-voltage range (2.8V-3.8V) corresponds to a current range of approximately 93mA-127mA; and the high-voltage range (3.8V-3.95V) corresponds to a current range of approximately 127mA-132mA.

[0059] In some embodiments of this application, the calculation of the equalization current range is based on specific voltage and resistance parameters. As an example, and not a limitation, when the single-cell voltage is 1.5V, the equalization current I = 1.5V / 30Ω = 50mA; when the single-cell voltage is 3.0V, the equalization current I = 3.0V / 30Ω = 100mA; and when the single-cell voltage is 3.95V, the equalization current I = 3.95V / 30Ω = 132mA. By dividing the voltage into segments, the equalization current range corresponding to each segment can be accurately determined, providing a basis for subsequent time ratio settings.

[0060] Step S115: Set the equalization time ratio for the corresponding voltage segments according to the equalization current range.

[0061] As an example, not a limitation, the balancing time ratio rule is set in stages based on the balancing current magnitude: When the balancing current is greater than 100mA, a 1:3 time ratio is used (balancing on time: balancing off time, i.e., balancing time: heat dissipation time). For example, 3.95V corresponds to 132mA current, using a 10-second on-time followed by a 30-second off-time. When the balancing current is in the range of 60mA-100mA, a 1:2 time ratio is used. For example, 3.0V corresponds to 100mA current, using a 10-second on-time followed by a 20-second off-time. When the balancing current is less than 60mA, a 1:1 time ratio is used. For example, 1.5V corresponds to 50mA current, using a 10-second on-time followed by a 10-second off-time.

[0062] In some embodiments of this application, the setting of the equalization time ratio fully considers the balance between temperature rise control and equalization efficiency. As an example, and not a limitation, the high-voltage section, due to its large equalization current (e.g., 132mA), employs a strategy of short-time activation combined with long heat dissipation time to effectively control temperature rise; the low-voltage section, due to its small equalization current (e.g., 50mA), uses a continuous equalization method to improve equalization speed. By dynamically adjusting the ratio of equalization activation time to equalization deactivation time, both the equalization effect and heat dissipation design requirements are ensured.

[0063] As an example, and not a limitation, the balancing current in the high-voltage range (3.8V-3.95V) can reach 127mA to 132mA, posing a higher risk of temperature rise. Specifically, when V=3.8V and R=30Ω, I=127mA, which falls within the high current range, requiring a 1:3 time ratio for temperature rise control. It's easy to understand that shortening the balancing time and extending the heat dissipation time can effectively prevent the balancing circuit board from overheating, ensuring safe system operation.

[0064] In some embodiments of this application, step S100 specifically includes the following steps, the flowchart of which is shown below. Figure 3 As shown:

[0065] Step S121: Obtain the individual cell voltage of each cell in the battery pack.

[0066] Sodium-ion battery packs typically consist of multiple individual cells connected in series, each with independent voltage characteristics. Specifically, the voltage acquisition circuit of the battery management system samples the voltage of each individual cell in the battery pack in real time to obtain the voltage value V_cell(i) of each individual cell, where i represents the cell number, ranging from 1 to n, and n is the number of cells in series in the battery pack.

[0067] In some embodiments of this application, the individual cell voltages are acquired using high-precision analog-to-digital converters for sampling. By way of example and not limitation, the voltage sampling frequency is set to an appropriate value to ensure the real-time nature and accuracy of the data, while taking into account the wide voltage range of sodium-ion batteries, from 1.5V to 3.95V. Specifically, each individual cell is sequentially selected for voltage measurement using a multiplexer, converting the analog voltage signal into a digital signal for subsequent processing.

[0068] It's easy to understand that sodium-ion batteries exhibit different voltage distribution characteristics under different operating conditions. As an example, and not a limitation, in the initial stage of charging, the voltage of each individual cell may be in a lower range; towards the end of charging, the voltage of each individual cell may approach its upper limit; and during discharge, the voltage of each individual cell gradually decreases. By continuously monitoring the voltage changes of each individual cell, the overall state of the battery pack and the differences between individual cells can be grasped in real time.

[0069] Step S122: Determine the minimum single-cell voltage among all single-cell voltages.

[0070] Due to differences in manufacturing processes, material properties, and usage history, individual cells in a battery pack will exhibit different voltage levels. As an example, and not a limitation, the minimum voltage value among all individual cells is identified as a benchmark reference point.

[0071] In some embodiments of this application, the minimum single-cell voltage is determined using a numerical comparison algorithm. As an example, and not a limitation, suppose the battery pack contains n single cells with voltages V_cell(1), V_cell(2), ..., V_cell(n), respectively. The minimum single-cell voltage V_cellMin is calculated using the formula V_cellMin = Min(V_cell(1), V_cell(2), ..., V_cell(n)). Specifically, by iterating through all single-cell voltage values ​​and comparing them one by one, the minimum voltage value and its corresponding cell number are finally determined.

[0072] As an example, and not a limitation, let's assume a sodium-ion battery pack containing 10 individual cells, with the following individual cell voltages: V_cell(1)=2.7V, V_cell(2)=2.5V, V_cell(3)=2.8V, V_cell(4)=2.6V, V_cell(5)=2.4V, V_cell(6)=2.3V, V_cell(7)=2.7V, V_cell(8)=2.5V, V_cell(9)=2.6V, and V_cell(10)=2.4V. Specifically, by comparison, we can determine that V_cellMin=2.3V, corresponding to cell number 6 as the cell with the lowest voltage.

[0073] In some embodiments of this application, the selection of the minimum cell voltage is dynamic. As an example and not a limitation, the voltage of different individual cells may change as the battery pack charges and discharges, and the cell number corresponding to the minimum cell voltage may change. Specifically, the value of the minimum cell voltage and its corresponding number need to be updated in real time to ensure the accuracy and effectiveness of the equalization control strategy.

[0074] Step S123: Determine the voltage range where the minimum single-cell voltage is located.

[0075] Specifically, voltage range determination is achieved through numerical comparison. It's easy to understand that when the minimum cell voltage V_cellMin satisfies 1.5V ≤ V_cellMin < 2.8V, it's determined to be in the low-voltage range; when it satisfies 2.8V ≤ V_cellMin < 3.8V, it's determined to be in the medium-voltage range; and when it satisfies 3.8V ≤ V_cellMin ≤ 3.95V, it's determined to be in the high-voltage range. As an example, and not a limitation, if the minimum cell voltage is 2.3V, it's determined to be in the low-voltage range, requiring the application of the corresponding equalization triggering conditions and control parameters for the low-voltage range.

[0076] In some embodiments of this application, the determination of the voltage range directly affects the subsequent equalization control strategy. As an example and not a limitation, when the minimum single-cell voltage is in the low-voltage range, due to the significant voltage change characteristics, a relatively lenient equalization triggering condition needs to be adopted to avoid false triggering caused by voltage change; when the minimum single-cell voltage is in the medium-voltage range, a balanced triggering condition setting is adopted; when the minimum single-cell voltage is in the high-voltage range, due to the significant polarization effect, a more stringent triggering condition needs to be adopted.

[0077] As an example, and not a limitation, let's assume that cell 6 in the battery pack has a voltage of 2.3V, which is the lowest single-cell voltage. Voltage range determination identifies it as being in the low-voltage range (1.5V-2.8V). Specifically, based on the characteristics of the low-voltage range, subsequent equalization control will employ trigger conditions of ΔV(i) > 50mV or ΔSOC(i) > 5%, along with corresponding equalization time ratio settings. By accurately determining the voltage range of the lowest single-cell voltage, the most suitable equalization control strategy can be selected for the entire battery pack.

[0078] In some embodiments of this application, step S200 specifically includes the following steps, the flowchart of which is shown below. Figure 4 As shown:

[0079] Step S211: Sample and obtain the individual cell voltage of each cell in the battery pack.

[0080] Specifically, the high-precision voltage acquisition circuit of the battery management system performs real-time voltage sampling on each individual cell in the battery pack to obtain the accurate voltage value V_cell(i) of each individual cell, where i is the cell number, ranging from 1 to n, and n is the total number of cells in the battery pack.

[0081] In some embodiments of this application, the sampling of the single-cell voltage takes into account the wide voltage range characteristics of sodium-ion batteries. By way of example and not limitation, the operating voltage range of sodium-ion batteries is 1.5V to 3.95V, spanning 2.45V, which is much larger than the voltage range of conventional lithium batteries. Specifically, the voltage sampling circuit needs to have sufficient accuracy and dynamic range to accurately capture voltage changes in each voltage segment, especially in the steep voltage change region of the low-voltage segment (1.5V-2.8V) and the significant polarization region of the high-voltage segment (3.8V-3.95V).

[0082] It should be noted that the timing and frequency of voltage sampling have a significant impact on the accuracy of equalization control. As an example, and not a limitation, the voltage of a sodium-ion battery changes dynamically during charging and discharging, especially at high rates, where polarization effects can cause voltage drift. Specifically, by appropriately setting the sampling frequency, real-time voltage changes can be captured while avoiding excessive system load due to overly frequent sampling.

[0083] Step S212: Calculate the voltage difference between the individual cell voltage and the minimum individual cell voltage of each battery.

[0084] Voltage difference is a key parameter for determining whether batteries need equalization. By comparing the voltage difference between each individual cell and the smallest individual cell, cells with excessively high voltage that require discharge equalization can be identified. As an example, and not a limitation, the voltage difference is calculated using the formula ΔV(i) = V_cell(i) – V_cellMin, where V_cellMin is the voltage of the smallest individual cell in the battery pack.

[0085] In some embodiments of this application, the calculation of the voltage difference needs to consider the characteristic differences of sodium-ion batteries at different voltage ranges. As an example, and not a limitation, assume the battery pack contains 10 individual cells, where cell number 6 has a voltage of 2.3V and is the minimum single-cell voltage V_cellMin, and cell number 3 has a voltage of 2.5V. Then, the voltage difference ΔV(3) for cell number 3 is 2.5V – 2.3V = 200mV. Specifically, this voltage difference will serve as an important basis for determining the subsequent equalization trigger condition.

[0086] As an example, and not a limitation, the distribution characteristics of voltage differences will vary when the battery pack is in different operating states. Specifically, in the initial stage of charging, the voltages of individual cells are relatively close, and the voltage difference is small; towards the end of charging, due to differences in the characteristics of individual cells, the voltage difference may increase significantly; after long-term use, due to different degrees of aging, the distribution of voltage differences may become more uneven. It is easy to understand that by calculating the voltage difference in real time, the inconsistency of the battery pack can be dynamically monitored.

[0087] Step S213: Determine whether the voltage difference is greater than the preset voltage difference.

[0088] The preset voltage difference is set differently according to the voltage range of the minimum single-cell voltage to adapt to the electrochemical characteristics of sodium-ion batteries in different voltage ranges. Specifically, when the minimum single-cell voltage is in the low-voltage range (1.5V-2.8V), the preset voltage difference SetVolt is set to 50mV; when the minimum single-cell voltage is in the medium-voltage range (2.8V-3.8V), the preset voltage difference SetVolt is set to 30mV; and when the minimum single-cell voltage is in the high-voltage range (3.8V-3.95V), the preset voltage difference SetVolt is set to 10mV.

[0089] In some embodiments of this application, the preset voltage difference setting fully considers the electrochemical characteristics of sodium-ion batteries. As an example, and not a limitation, in the low-voltage range, due to the characteristics of the voltage abrupt change region, the voltage difference is large, but the actual SOC difference may be small. Therefore, a relatively lenient 50mV threshold is adopted to avoid false triggering caused by abrupt voltage changes. Specifically, when ΔV(i) = 200mV > 50mV, although the voltage difference is large, it still meets the triggering condition because it is in the low-voltage range, and equalization processing is required.

[0090] It should be noted that in the medium-voltage range, the relationship between voltage and remaining capacity (or state of charge) is relatively linear and stable. A moderate threshold of 30mV is used to achieve joint determination of voltage difference and remaining capacity difference (or state of charge difference). Specifically, when the voltage difference ΔV(i) of a certain single cell is greater than 30mV, it indicates that there is a significant difference between this cell and the smallest single cell, and further determination of the remaining capacity difference (or state of charge difference) is required.

[0091] Similarly, the high-voltage section employs a stricter 10mV threshold setting, thus requiring joint determination of the voltage difference and the remaining capacity difference (or state of charge difference). As an example, and not a limitation, in the high-voltage section (3.8V-3.95V), due to significant polarization effects and proximity to the charging upper limit, precise control is needed to avoid overcharging risks. Specifically, when the voltage difference ΔV(i) > 10mV, further adjustments to the remaining capacity difference (or state of charge difference) are necessary.

[0092] It's easy to understand that the voltage difference determination directly determines which individual cells need to undergo equalization. As an example, and not a limitation, by comparing the calculated voltage difference ΔV(i) with the preset voltage difference SetVolt for the corresponding voltage segment, when ΔV(i) > SetVolt, the individual cell is determined to meet the equalization trigger condition. Specifically, individual cells that meet the condition will be marked as cells to be equalized and enter the subsequent group equalization process.

[0093] Step S214: The corresponding battery meets the first equalization trigger condition.

[0094] When the voltage difference of a single cell exceeds a preset voltage difference, that cell is identified as a cell requiring equalization. It's easy to understand that the first equalization trigger condition is based on the voltage difference criterion, providing a clear trigger basis for subsequent equalization control.

[0095] In some embodiments of this application, batteries that meet the first equalization trigger condition will be recorded and managed. As an example, and not a limitation, the system records the battery serial numbers that meet the condition, establishing a list of batteries to be equalized, providing a data foundation for subsequent group equalization algorithms. Specifically, assuming that the voltage differences of batteries 1, 3, 5, 8, and 10 in the battery pack all exceed their respective preset voltage differences, these batteries all meet the first equalization trigger condition and need to be included in the list of batteries to be equalized for processing.

[0096] As an example, and not a limitation, the determination of the first equalization trigger condition is dynamic. Specifically, as the equalization process progresses, the voltage of each individual cell changes, and the voltage difference changes accordingly. The number and distribution of cells that meet the trigger condition may be dynamically adjusted. Continuous monitoring and updating of the trigger condition determination results are necessary to ensure the real-time performance and accuracy of the equalization control.

[0097] In some other embodiments of this application, step S200 specifically includes the following steps, the flowchart of which is shown below. Figure 5 As shown:

[0098] Step S221: Sample and obtain the remaining capacity or state of charge of each battery in the battery pack.

[0099] State of Charge (SOC) represents the percentage of remaining battery capacity and is an important parameter for assessing battery status and equalization requirements. Specifically, the SOC estimation algorithm of the battery management system, combined with voltage, current, and temperature parameters, obtains the SOC_cell(i) of each individual cell in the battery pack, where i is the cell number, ranging from 1 to n, and n is the total number of battery cells in the pack.

[0100] In some embodiments of this application, SOC estimation for sodium-ion batteries faces unique challenges. As an example, and not a limitation, the voltage-remaining capacity (or state of charge) relationship of sodium-ion batteries exhibits nonlinear characteristics in the low-voltage steep-change region (1.5V-2.8V), where the estimation error of the traditional ampere-hour integral method can reach 8%, requiring correction using a piecewise linearization model. Specifically, differentiated SOC estimation strategies are employed for different voltage ranges: the low-voltage range focuses on the steep voltage change characteristics, the medium-voltage range utilizes the relatively linear voltage-remaining capacity relationship, and the high-voltage range considers the impact of polarization effects on SOC estimation.

[0101] It's easy to understand that the accuracy of SOC sampling directly affects the effectiveness of equalization triggering based on the difference in remaining capacity (or state of charge). As an example, and not a limitation, SOC estimation for sodium-ion batteries requires comprehensive consideration of multiple parameters such as voltage, current, and temperature. Especially during high-rate charge and discharge, polarization effects can cause voltage shifts, thus affecting the accuracy of SOC estimation. By employing a low-computing-power SOC estimation algorithm, the reliance on processor computing power can be reduced while maintaining estimation accuracy.

[0102] Step S222: Determine the minimum remaining capacity (or minimum state of charge) in each battery.

[0103] The minimum value among all individual cells is found by comparing their remaining capacity values ​​and used as a reference point for calculating the difference in remaining capacity; or the minimum value among all individual cells is found by comparing their state of charge and used as a reference point for calculating the difference in state of charge.

[0104] In some embodiments of this application, the determination of the minimum remaining capacity (or minimum state of charge) is implemented using a numerical comparison algorithm. As an example, and not a limitation, suppose the battery pack contains n individual cells with states of charge SOC_cell(1), SOC_cell(2), ..., SOC_cell(n), respectively. The minimum state of charge SOC_cellMin is calculated using the formula SOC_cellMin = Min(SOC_cell(1), SOC_cell(2), ..., SOC_cell(n)). Specifically, by iterating through the states of charge of all individual cells and comparing them one by one, the minimum state of charge and its corresponding cell number are finally determined.

[0105] As an example, and not a limitation, suppose a sodium-ion battery pack contains 10 individual cells with the following states of charge (SOC): SOC_cell(1)=85%, SOC_cell(2)=82%, SOC_cell(3)=88%, SOC_cell(4)=80%, SOC_cell(5)=79%, SOC_cell(6)=78%, SOC_cell(7)=84%, SOC_cell(8)=81%, SOC_cell(9)=83%, and SOC_cell(10)=77%. Specifically, by comparison, we can determine that SOC_cellMin=77%, corresponding to cell number 10 as the cell with the lowest state of charge.

[0106] It's easy to understand that determining the minimum remaining capacity (or minimum state of charge) provides an important benchmark for calculating subsequent remaining capacity differences (or state of charge differences). As an example, and not a limitation, using the minimum remaining capacity (or minimum state of charge) as a benchmark allows us to calculate the remaining capacity differences (or state of charge differences) between other individual cells and the benchmark cell, thereby determining which individual cells have excessively high remaining capacity (or state of charge) and require equalization processing. Specifically, the result of calculating the state of charge difference ΔSOC(i) = SOC_cell(i) – SOC_cellMin will serve as an important basis for determining the equalization trigger condition.

[0107] In some embodiments of this application, the selection of the minimum remaining capacity (or minimum state of charge) is dynamic. As an example and not a limitation, the remaining capacity (state of charge) of different individual cells may change as the battery pack charges and discharges, and the cell number corresponding to the minimum remaining capacity (minimum state of charge) may change. Specifically, the value of the minimum remaining capacity (minimum state of charge) and its corresponding number need to be updated in real time to ensure that the equalization control strategy is based on accurate capacity state information.

[0108] Step S223: Calculate the difference between the remaining capacity of each battery and the minimum remaining capacity; or calculate the difference between the state of charge of each battery and the minimum state of charge.

[0109] Specifically, the remaining capacity difference (state of charge difference) is the core parameter for determining whether batteries need equalization. By comparing the differences between each individual cell and the cell with the minimum remaining capacity (minimum state of charge), cells with excessively high remaining capacity (state of charge) that require discharge equalization can be identified. It's easy to understand that the state of charge difference is calculated using the formula ΔSOC(i) = SOC_cell(i) – SOC_cellMin, where SOC_cellMin is the minimum state of charge in the battery pack.

[0110] In some embodiments of this application, the calculation of the remaining capacity difference (state of charge difference) needs to take into account the capacity characteristics of the sodium-ion battery. By way of example and not limitation, based on the foregoing example, assuming that the remaining capacity of battery No. 1 is 85% and the minimum remaining capacity is 77% (corresponding to battery No. 10), then the state of charge difference ΔSOC(1) of battery No. 1 is 85% – 77% = 8%. Specifically, this state of charge difference reflects the power advantage of battery No. 1 relative to the battery with the lowest state of charge, and this difference needs to be eliminated through equal discharge.

[0111] As an example, and not a limitation, the distribution characteristics of the remaining capacity difference (state-of-charge difference) can reflect the degree of inconsistency in a battery pack. Specifically, when the remaining capacity difference (state-of-charge difference) of each individual cell is relatively small, it indicates that the battery pack has good consistency; when the remaining capacity difference (state-of-charge difference) of some cells is large, it indicates significant inconsistency, requiring equalization processing. It is easy to understand that by continuously monitoring the changing trend of the remaining capacity difference (state-of-charge difference), the health status and equalization needs of the battery pack can be assessed.

[0112] In some embodiments of this application, the accuracy of the remaining capacity difference (state-of-charge difference) calculation affects the effectiveness of equalization control. As an example, and not a limitation, the accuracy of the SOC estimation for sodium-ion batteries directly affects the accuracy of the remaining capacity difference (state-of-charge difference), and consequently, the reliability of the equalization trigger judgment. Specifically, by employing a high-precision SOC estimation algorithm and appropriate filtering, the accuracy of the remaining capacity difference (state-of-charge difference) calculation can be improved, reducing false triggers or missed triggers caused by estimation errors.

[0113] Step S224: Determine whether the remaining capacity difference is greater than the preset remaining capacity difference; or determine whether the state of charge difference is greater than the preset state of charge difference.

[0114] The preset remaining capacity difference (state of charge difference) is set differently according to the voltage range of the smallest single cell voltage to adapt to the balancing needs of sodium-ion batteries under different operating conditions. Specifically, when the smallest single cell voltage is in the low voltage range (1.5V-2.8V), the preset state of charge difference SetSOC is set to 5%; when the smallest single cell voltage is in the medium voltage range (2.8V-3.8V), the preset state of charge difference SetSOC is set to 2%; and when the smallest single cell voltage is in the high voltage range (3.8V-3.95V), the preset state of charge difference SetSOC is set to 0.5%.

[0115] In some embodiments of this application, the preset remaining capacity difference (state of charge difference) setting fully considers the electrochemical characteristics of sodium-ion batteries. As an example, and not a limitation, in the low-voltage range, due to the characteristics of the voltage steep change region and the influence of SOC estimation errors, a relatively lenient 5% threshold is adopted to avoid frequent triggering due to estimation errors. Specifically, when ΔSOC(i) = 8% > 5%, it indicates a significant difference between the battery and the battery with the minimum remaining capacity (minimum state of charge), satisfying the equalization triggering condition.

[0116] It should be noted that in the medium-voltage range, the relationship between voltage and state of charge (SOC) is relatively stable, and the SOC estimation accuracy is high. A moderate threshold of 2% is used, therefore, a joint determination of the voltage difference and the SOC difference is necessary. Specifically, when the SOC difference ΔSOC(i) of a single cell exceeds 2%, it is also necessary to determine whether the voltage difference ΔV(i) is greater than the preset voltage threshold for the medium-voltage range. If so, it indicates that the cell needs to undergo equalization processing to eliminate capacity differences. It is easy to understand that the threshold setting in the medium-voltage range balances the requirements for trigger sensitivity and control stability.

[0117] Similarly, the high-voltage section employs a more stringent 0.5% threshold setting, thus requiring joint judgment of voltage difference and state-of-charge difference. As an example, and not a limitation, in the high-voltage section (3.8V-3.95V), due to proximity to the charging upper limit and significant polarization effects, precise control is necessary to ensure safety. Specifically, when the state-of-charge difference ΔSOC(i) > 0.5%, it is also necessary to determine whether the voltage difference ΔV(i) is greater than the preset voltage threshold of the high-voltage section. If so, it is considered that balancing is required, reflecting the stringent requirements for balancing accuracy and safety in the high-voltage section.

[0118] It's easy to understand that the results of the remaining capacity difference (state-of-charge difference) and the voltage difference together constitute the basis for determining the equalization trigger condition. As an example, and not a limitation, in some voltage ranges, the equalization trigger condition may use an OR logic relationship between the voltage difference and the remaining capacity difference (state-of-charge difference), while in other voltage ranges it may use an AND logic relationship. Specifically, through flexible logic combinations, the characteristic requirements of different voltage ranges can be adapted to improve the accuracy of equalization control.

[0119] Step S225: The corresponding battery meets the first equalization trigger condition.

[0120] When the remaining capacity difference (state of charge difference) of a certain individual cell is greater than a preset remaining capacity difference (state of charge difference), that cell is identified as a cell that needs to be equalized. It is easy to understand that the first equalization trigger condition based on the remaining capacity difference (state of charge difference) provides an important means of assessing equalization needs from the perspective of remaining capacity, complementing the judgment method based on voltage difference.

[0121] In some embodiments of this application, batteries that meet the first equalization trigger condition will be managed and processed uniformly. As an example and not a limitation, batteries that meet the trigger condition based on either voltage difference or remaining capacity difference (state of charge difference) will be included in the battery list to be equalized, providing a complete data foundation for subsequent group equalization algorithms. Specifically, assuming that batteries 1, 3, and 7 meet the trigger condition based on remaining capacity difference (state of charge difference), these batteries will be merged with batteries that meet the condition based on voltage difference to form a complete battery list to be equalized.

[0122] It should be noted that the equalization triggering judgment method based on the remaining capacity difference (state of charge difference) has good complementary value. Specifically, in some cases, the voltage difference may not be accurate enough due to measurement errors or instantaneous fluctuations, while the remaining capacity difference (state of charge difference) can provide a more stable judgment basis; in other cases, capacity estimation may have accumulated errors, while the voltage difference can provide a real-time status reflection. The combined use of the two judgment methods can improve the reliability and comprehensiveness of equalization triggering judgment.

[0123] In some other embodiments of this application, step S300 specifically includes the following steps, the flowchart of which is shown below. Figure 6 As shown:

[0124] Step S310: Record the serial number of the battery to be balanced.

[0125] Based on the aforementioned determination of the equalization trigger conditions, the individual battery cells that meet the equalization criteria have been identified. It is necessary to record and manage the serial numbers of these batteries. Specifically, a list of batteries to be equalized is established, recording the serial number of each battery that meets the equalization trigger conditions, providing a data foundation for the subsequent grouping algorithm.

[0126] In some embodiments of this application, the records of the battery numbers to be balanced are managed using an ordered list. As an example, and not a limitation, assuming the battery pack contains 12 individual cells, and after determining the balancing trigger condition, it is determined that batteries with serial numbers 1, 2, 3, 4, 5, 6, 8, 9, 10, and 12 need to be balanced, then the list of batteries to be balanced is recorded as (1, 2, 3, 4, 5, 6, 8, 9, 10, 12). Specifically, the cells are arranged according to their natural serial numbers to facilitate the execution of subsequent grouping algorithms.

[0127] It's easy to understand that accurately recording the serial numbers of the batteries to be balanced is fundamental to group control. As an example, and not a limitation, let's assume the number of battery pack strings is N. In this example, N=12, so the batteries to be balanced need to be divided into two groups, with each group balancing a maximum of N / 2=6 batteries per cycle. A reasonable grouping strategy is needed to ensure balancing efficiency while avoiding current superposition and localized temperature rise issues caused by balancing adjacent batteries simultaneously.

[0128] Step S320: Determine whether the number of batteries to be balanced is greater than the preset number.

[0129] The preset quantity is half the number of battery pack strings, i.e., N / 2. As an example rather than a limitation, when the number of battery pack strings N=12, the preset quantity is 6; when the number of batteries to be balanced n is greater than 6, they need to be divided into two groups for alternating balancing; when the number of batteries to be balanced n is less than or equal to 6, they can be considered to be grouped into one group for balancing.

[0130] In some embodiments of this application, the determination of the number of batteries to be balanced determines the subsequent grouping strategy. As an example and not a limitation, based on the foregoing example, the list of batteries to be balanced (1,2,3,4,5,6,8,9,10,12) contains 10 batteries, n=10>N / 2=6, therefore, they need to be divided into two groups for balancing.

[0131] When the number of batteries to be balanced is not greater than the preset number, step S340 is executed;

[0132] Step S330: According to the serial number of the batteries to be balanced, the batteries are alternately distributed from small to large, and the batteries to be balanced are divided into the first battery group and the second battery group.

[0133] As an example rather than a limitation, the grouping principle follows an alternating allocation algorithm: the first group is allocated the battery with the lowest serial number, the second group is allocated the battery with the second lowest serial number, and then the battery with the third serial number is allocated to the first group, and so on, alternating in sequence.

[0134] Specifically, based on the aforementioned list of batteries to be balanced (1,2,3,4,5,6,8,9,10,12), the grouping example is as follows: the first battery group to be balanced contains batteries with serial numbers 1, 3, 5, 8, and 10; the second battery group to be balanced contains batteries with serial numbers 2, 4, 6, 9, and 12. It is easy to understand that by alternating the allocation, the number of batteries to be balanced in the two groups is basically the same, and the balancing serial numbers of adjacent batteries are not in the same group, avoiding the risk of adjacent batteries being balanced simultaneously.

[0135] In some embodiments of this application, the grouping algorithm employs a dynamic alternating allocation logic. As an example and not a limitation, allocation is performed according to the first group priority principle: after sorting the list of batteries to be balanced by serial number, the first battery is allocated to the first group, the second battery to the second group, the third battery to the first group, the fourth battery to the second group, and so on, alternating until all batteries to be balanced are grouped, ensuring the uniformity of grouping and the isolation of adjacent batteries.

[0136] As an example, and not a limitation, the execution strategy after grouping is completed uses a time-sharing grouping cycle for balancing. Specifically, cycle 1 prioritizes processing batteries that meet the conditions in the first group (1, 3, 5, 8, 10...); cycle 2 processes batteries that meet the conditions in the second group (2, 4, 6, 9, 12...); and so on until balancing is complete. By using a time-sharing approach, the orderly balancing process is ensured, while avoiding excessive system load caused by balancing too many batteries simultaneously.

[0137] In some embodiments of this application, the grouping strategy also includes a demand pausing mechanism. By way of example and not limitation, the balancing demands of the second group are paved during the processing of the first group to avoid loss across cycles. While the first group is performing balancing operations, the balancing demands of the second group are temporarily stored, waiting for the first group to complete before being processed, ensuring that all balancing demands are responded to in a timely manner.

[0138] Step S340: Determine whether there are adjacent cells to be equalized.

[0139] Specifically, the necessity of grouping is further determined by checking whether there are batteries with adjacent serial numbers in the list of batteries to be balanced. It is easy to understand that even if the number of batteries to be balanced is small, if there are adjacent batteries that need to be balanced, they should be grouped to avoid the risk of adjacent batteries being balanced at the same time.

[0140] In some embodiments of this application, the determination of adjacent batteries is based on the detection of serial number differences. As an example, and not a limitation, by calculating the difference between two adjacent serial numbers in the list of batteries to be balanced, if |ij|=1, it indicates the existence of adjacent batteries to be balanced. Specifically, the adjacent battery isolation rule detects adjacency through serial number differences to ensure a safe distance and avoid local current superposition caused by simultaneous balancing operations on adjacent batteries.

[0141] When the number of batteries to be balanced is less than or equal to the preset number and there are no batteries with adjacent serial numbers to be balanced, step S350 is executed.

[0142] Step S350: Equalize all batteries to be equalized according to the ratio of the preset equalization time to the equalization time of the first equalization trigger condition.

[0143] In this scenario, all batteries to be balanced can be grouped together and balanced simultaneously, improving balancing efficiency and shortening balancing time.

[0144] The core of the time-sharing group dynamic logic lies in optimizing balancing efficiency and controlling system risk. As an example, and not a limitation, when the number of balancing batteries is small and they are not adjacent, a single-group simultaneous balancing strategy is used to improve efficiency; when the number of balancing batteries is large or there are adjacent batteries, a dual-group alternating balancing strategy is used to control risk. Specifically, this dynamic logic achieves a balance between efficiency and safety, adapting to the needs of different balancing scenarios.

[0145] In some other embodiments of this application, step S400 specifically includes the following steps, the flowchart of which is shown below. Figure 7 As shown:

[0146] Step S410: Obtain the first heat dissipation time based on the ratio of the preset equalization time to the equalization time of the first equalization trigger condition.

[0147] In some embodiments of this application, the calculation of the first heat dissipation time is based on a tiered setting of the equalization current. As an example and not a limitation, the formula for calculating the equalization current is I(i) = V_cell(i) / R, where R is the equalization resistance value of 30Ω. Specifically, different ranges of equalization current are generated depending on the individual cell voltage V_cell(i): the current can reach 127mA to 132mA in the high-voltage segment (above 3.8V), approximately 93mA to 127mA in the medium-voltage segment (2.8V-3.8V), and approximately 50mA to 93mA in the low-voltage segment (1.5V-2.8V).

[0148] It's easy to understand that the equalization time ratio rule is set differently based on the equalization current range. As an example, and not a limitation, when the equalization current is greater than 100mA, a 1:3 time ratio (on:off) is used, meaning that when the preset equalization time is 10 seconds, the first heat dissipation time is 30 seconds; when the equalization current is in the range of 60mA-100mA, a 1:2 time ratio is used, meaning that when the preset equalization time is 10 seconds, the first heat dissipation time is 20 seconds; and when the equalization current is less than 60mA, a 1:1 time ratio is used, meaning that when the preset equalization time is 10 seconds, the first heat dissipation time is 10 seconds.

[0149] In some embodiments of this application, the first heat dissipation time is determined by fully considering the temperature rise characteristics of sodium-ion batteries. As an example, and not a limitation, when the single-cell voltage is 3.95V, the balancing current I = 3.95V / 30Ω = 132mA, which falls within the high current range greater than 100mA. Based on a 1:3 time ratio, with a preset balancing time of 10 seconds, the first heat dissipation time is 30 seconds. Due to the large balancing current and significant heat generation in the high-voltage section, a strategy of short-time activation combined with a long heat dissipation time is adopted to effectively control the temperature rise and prevent the balancing circuit board from overheating.

[0150] It's easy to understand that determining the initial cooling time requires dynamic calculation based on the voltage state of the specific cells in the battery pack to be balanced. As an example, and not a limitation, for each cell in both the first and second battery packs to be balanced, a corresponding balancing current needs to be calculated based on its current voltage to determine the applicable time ratio rule. When the voltage differences between different cells within the same group are significant, the most stringent time ratio requirement within that group may need to be adopted to ensure the safe balancing of all cells.

[0151] Step S420: Equalize the first battery pack to be equalized and the second battery pack to be equalized in sequence according to the preset equalization time and the first heat dissipation time.

[0152] The time-sharing and grouping balanced execution strategy needs to be strictly controlled according to the preset time parameters to ensure that the expected results are achieved in each balancing cycle. As an example rather than a limitation, the balanced execution adopts the first group priority principle. In each cycle, the first group's needs are processed first, and then the second group is switched to. This cycle continues until all balancing tasks are completed.

[0153] In some embodiments of this application, the timing control of the equalization execution employs a precise time management mechanism. As an example, and not a limitation, when processing the first battery pack to be equalized, the equalization circuit of the corresponding battery is activated according to a preset equalization time (e.g., 10 seconds), and then the equalization circuit is deactivated according to a first heat dissipation time (e.g., 30 seconds, 20 seconds, or 10 seconds) to allow for heat dissipation and waiting. Specifically, after completing one equalization cycle of the first group, the system immediately switches to the second battery pack to be equalized, executing the same time control strategy.

[0154] As an example, and not a limitation, the specific timing control during the equalization process is illustrated below: Assuming the first battery pack to be equalized contains a 3.8V high-voltage battery with a corresponding equalization current of 127mA, and using a 1:3 time ratio, the equalization process for this pack involves 10 seconds of equalization on and 30 seconds of cooling off. The second battery pack to be equalized contains a 2.5V low-voltage battery with a corresponding equalization current of 83mA, and using a 1:2 time ratio, the equalization process for this pack involves 10 seconds of equalization on and 20 seconds of cooling off. Specifically, the two packs are executed alternately to ensure orderly equalization and effective heat dissipation.

[0155] In some embodiments of this application, the sequential equalization execution strategy includes a demand status monitoring function. It is easy to understand that during the equalization process, it is necessary to continuously monitor the voltage and remaining capacity (or SOC) status of each battery to determine whether the equalization triggering conditions are still met. As an example, and not a limitation, when a battery's voltage difference or remaining capacity difference (or state of charge difference) has decreased below the trigger threshold after several equalization cycles, that battery can be removed from the equalization queue to reduce unnecessary equalization operations.

[0156] In some embodiments of this application, the battery balancing control method further includes the following steps:

[0157] Step S500: Obtain the difference in remaining capacity of each battery to be balanced based on the remaining capacity threshold corresponding to the first equalization trigger condition, or based on the state of charge threshold corresponding to the first equalization trigger condition.

[0158] The remaining capacity difference is a key parameter for determining the balancing task and directly affects the calculation of the balancing time. Specifically, the remaining capacity difference is calculated using the formula ΔQtarget(i) = (ΔSOC(i) – SetSOC) × Cnom, where ΔSOC(i) is the state-of-charge difference of the i-th battery, SetSOC is the capacity threshold corresponding to the first balancing trigger condition, and Cnom is the nominal capacity of the battery.

[0159] In some embodiments of this application, the state-of-charge threshold SetSOC is set differently based on the voltage range of the minimum single-cell voltage. As an example, and not a limitation, when the minimum single-cell voltage is in the low-voltage range (1.5V-2.8V), SetSOC=5%; when the minimum single-cell voltage is in the medium-voltage range (2.8V-3.8V), SetSOC=2%; and when the minimum single-cell voltage is in the high-voltage range (3.8V-3.95V), SetSOC=0.5%. Specifically, assuming a sodium-ion battery pack with a nominal capacity of 100Ah, where a certain battery has a remaining capacity SOC=95% and is currently operating in the medium-voltage range (SetSOC=2%), and the minimum remaining capacity is 90%, then the state-of-charge difference ΔSOC(i) of this battery is 95%-90%=5%, and the remaining capacity difference ΔQtarget(i) is (5%-2%)×100Ah=3Ah.

[0160] It's easy to understand that the calculation of the remaining capacity difference needs to take into account the actual demand for equalization. As an example rather than a limitation, only the portion exceeding the remaining capacity threshold (or state of charge threshold SetSOC) needs equalization processing; therefore, the actual remaining capacity difference is the portion of capacity exceeding the threshold.

[0161] Step S600: Obtain the maximum remaining capacity difference between the two sets of battery packs to be balanced.

[0162] Because a group balancing strategy is adopted, it is necessary to calculate the maximum remaining capacity difference between the first and second battery groups to be balanced separately to determine the balancing time of each group. As an example and not a limitation, the maximum remaining capacity difference of the first group is calculated using the formula ΔQtarget1 = Max(ΔQtarget(a), ΔQtarget(c)...), where a, c, etc. are the serial numbers of the batteries in the first group to be balanced; the maximum remaining capacity difference of the second group is calculated using the formula ΔQtarget2 = Max(ΔQtarget(b), ΔQtarget(d)...), where b, d, etc. are the serial numbers of the batteries in the second group to be balanced.

[0163] In some embodiments of this application, the determination of the maximum remaining capacity difference is based on the actual demand analysis of the batteries in each group. As an example, and not a limitation, assuming the first group of batteries to be balanced includes batteries numbered 1, 3, and 5, with remaining capacity differences of ΔQtarget(1) = 5 Ah, ΔQtarget(3) = 3 Ah, and ΔQtarget(5) = 4 Ah respectively, then the maximum remaining capacity difference of the first group is ΔQtarget1 = Max(5 Ah, 3 Ah, 4 Ah) = 5 Ah. Specifically, the maximum remaining capacity difference determines the balancing time of the group, because the entire group can only complete the balancing task after the battery with the largest capacity difference has completed balancing.

[0164] As an example rather than a limitation, the second group of batteries to be balanced includes batteries numbered 2, 4, and 6, with remaining capacity differences of ΔQtarget(2) = 2Ah, ΔQtarget(4) = 3.5Ah, and ΔQtarget(6) = 2.8Ah, respectively. Therefore, the maximum remaining capacity difference of the second group is ΔQtarget2 = Max(2Ah, 3.5Ah, 2.8Ah) = 3.5Ah.

[0165] Step S700: Based on the preset equalization time and the voltage range where the minimum single-cell voltage is located, obtain the corresponding single discharge quantity.

[0166] The discharge capacity per cycle is calculated using the formula ΔQ(i) = I(i) × t_on, where I(i) is the balancing current and t_on is the preset balancing time (on-time). Specifically, the balancing current is calculated as I(i) = V_cell(i) / R, where R is the balancing resistance value of 30Ω and V_cell(i) is the voltage of a single cell.

[0167] In some embodiments of this application, the calculation of single discharge capacity needs to consider the current characteristics of different voltage ranges. As an example, and not a limitation, when the single-cell voltage is 3.95V and the preset equalization time t_on = 10 seconds, the equalization current I = 3.95V / 30Ω = 132mA, then the single discharge capacity ΔQ = 0.132A × 10s = 1.32C ≈ 0.000367Ah. Specifically, in the high-voltage range, due to the higher voltage, the equalization current is larger, and the single discharge capacity is correspondingly larger; in the low-voltage range, due to the lower voltage, the equalization current is smaller, and the single discharge capacity is correspondingly smaller.

[0168] As an example, and not a limitation, when the single-cell voltage is 2.0V and the preset equalization time t_on = 10 seconds, the equalization current I = 2.0V / 30Ω = 67mA. Therefore, the single discharge capacity ΔQ = 0.067A × 10s = 0.67C ≈ 0.000186Ah. Different voltage ranges correspond to different single discharge capacities, which directly affect the number of equalization cycles and the total time required to reach the target remaining capacity difference.

[0169] In some embodiments of this application, the corresponding single discharge capacity needs to be determined based on the battery corresponding to the maximum remaining capacity difference between the two groups. It is easy to understand that, due to the characteristics of group balancing, the balancing time of each group is determined by the battery with the maximum remaining capacity difference within that group. As an example, and not a limitation, if the battery number corresponding to the maximum remaining capacity difference in the first group is getMaxQtarget1Num, then the single discharge capacity of the first group is ΔQ1 = ΔQ(getMaxQtarget1Num); if the battery number corresponding to the maximum remaining capacity difference in the second group is getMaxQtarget2Num, then the single discharge capacity of the second group is ΔQ2 = ΔQ(getMaxQtarget2Num).

[0170] Step S800: Obtain the total equalization time based on the preset equalization time, the maximum remaining capacity difference, the corresponding single discharge amount, and the equalization time ratio of the first equalization trigger condition.

[0171] The calculation of the total balancing time needs to comprehensively consider multiple factors such as the balancing workload, single-cycle balancing capacity, and time ratio control. As an example rather than a limitation, the calculation of the total balancing time for the first group uses the formula T_total1 = ΔQtarget1 / ΔQ1 × (T_on + T_off), where T_on is the preset balancing time and T_off is the heat dissipation time determined according to the balancing time ratio.

[0172] In some embodiments of this application, the calculation of the total equalization time fully considers the influence of dynamic time ratio control. As an example and not a limitation, based on the foregoing example, assuming the maximum remaining capacity difference of the first group is ΔQtarget1 = 5Ah = 18000C, corresponding to the single discharge capacity of the battery ΔQ1 = 1.32C, the preset equalization time T_on = 10 seconds, and the heat dissipation time T_off = 30 seconds (at a 1:3 time ratio), then the required number of equalization cycles is 18000C / 1.32C ≈ 13636, and the single cycle time is 10s + 30s = 40 seconds. Therefore, the total equalization time of the first group is T_total1 = 13636 × 40s ≈ 151.5 hours.

[0173] As an example, not a limitation, the calculation method for the total balancing time of the second group is similar, using the formula T_total2 = ΔQtarget2 / ΔQ2 × (T_on + T_off). Specifically, assuming the maximum remaining capacity difference of the second group is ΔQtarget2 = 3.5Ah = 12600C, corresponding to a battery voltage of 3.0V, a balancing current of 100mA, a single discharge amount of ΔQ2 = 1.0C, and a time ratio of 1:2, then T_on = 10 seconds, T_off = 20 seconds, the single cycle time is 30 seconds, and the total balancing time of the second group is T_total2 = 12600 / 1.0 × 30s = 105 hours.

[0174] It's easy to understand that the total balancing time is the sum of the balancing times of the two groups. As an example, and not a limitation, the total balancing time is calculated using the formula T_total = T_total1 + T_total2. Specifically, based on the previous example, the total balancing time T_total = 151.5 hours + 105 hours = 256.5 hours. When only one group needs balancing, the time for the other group, T_total2 = 0, and the total balancing time is the balancing time for that single group.

[0175] Unlike existing technologies, the embodiments of the present invention can achieve differentiated equalization triggering by dividing the voltage into multiple segments to take into account the wide voltage range characteristics of sodium-ion batteries. By using time-division group equalization and dynamic time ratio control, the equalization temperature rise can be effectively reduced and the equalization efficiency can be improved, with good hardware compatibility.

[0176] The present invention also provides an electronic device based on the above-described battery balancing control method, the schematic diagram of which is shown below. Figure 8 As shown, the electronic device 100 includes:

[0177] One or more processors 101, a network interface 102, and a memory 103, Figure 8 The example consists of a processor 101, a network interface 102, and a memory 103.

[0178] The network interface 102 is communicatively connected to the corresponding processor 101, and the processor 101 and the memory 103 can be connected via a bus or other means. Figure 8 Taking the example of a connection between China and Israel via a bus.

[0179] The network interface 102 is used to establish communication connections between the processor 101 and other external devices, including the following types: RJ-45 interface, SC fiber optic interface, AUI interface, FDDI interface and Console interface.

[0180] The memory 103, as a non-volatile computer-readable storage medium, can be used to store non-volatile software programs, non-volatile computer-executable programs, and modules. The processor 101 executes various functional applications and data processing of the electronic device by running the non-volatile software programs, instructions, and units stored in the memory 103, thereby implementing the battery equalization control method of the above-described method embodiment.

[0181] The memory 103 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created based on the use of the electronic device. Furthermore, the memory 103 may include high-speed random access memory and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other non-volatile solid-state storage device. In some embodiments, the memory 103 may optionally include memory remotely located relative to the processor 101, and these remote memories can be connected to the electronic device via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0182] The one or more units are stored in the memory 103, and when executed by one or more processors 101, they execute the battery equalization control method in any of the above method embodiments.

[0183] The aforementioned electronic device can execute the battery balancing control method provided in the embodiments of the present invention, and has the corresponding program modules and beneficial effects for executing the method. Technical details not described in detail in the electronic device embodiments can be found in the battery balancing control method provided in the embodiments of the present invention.

[0184] This invention also provides a non-volatile computer-readable storage medium, which may be included in the device described in the above embodiments; or it may exist independently and not assembled into the device. The non-volatile computer-readable storage medium carries one or more programs, which, when executed, implement the battery balancing control method of this disclosure.

[0185] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them; under the concept of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of this application as described above. For the sake of brevity, they are not provided in detail; although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A battery equalization control method characterized by, The method comprises the following steps: determining the voltage section where the minimum single cell voltage in the battery pack is located; each preset voltage section corresponds to an equalization trigger condition and an equalization time ratio; determining whether each battery in the battery pack meets the first equalization trigger condition; the first equalization trigger condition is the equalization trigger condition of the voltage section where the minimum single cell voltage is located; when the number of batteries to be equalized is greater than a preset number or there are adjacent serial numbers of batteries to be equalized, the batteries to be equalized are divided into two groups according to the serial number order of the batteries to be equalized by alternating allocation; the batteries to be equalized are the batteries meeting the first equalization trigger condition; according to the preset equalization time and the equalization time ratio of the first equalization trigger condition, the two groups of batteries to be equalized are sequentially equalized; the equalization time ratio is the ratio of the equalization time to the heat dissipation time; each preset voltage section comprises: monitoring the voltage change amount and the battery capacity change amount of the battery; dividing the battery voltage range into several voltage sections according to the ratio of the voltage change amount to the battery capacity change amount; setting the corresponding equalization trigger condition for the several voltage sections; obtaining the corresponding equalization current range according to the several voltage sections; setting the equalization time ratio for the corresponding several voltage sections according to the equalization current range.

2. The method of claim 1, wherein, The method comprises the following steps: obtaining the single cell voltage of each battery in the battery pack; determining the minimum single cell voltage among the single cell voltages; determining the voltage section where the minimum single cell voltage is located.

3. The method of claim 1, wherein, The method comprises the following steps: sampling and obtaining the single cell voltage of each battery in the battery pack; calculating the voltage difference between the single cell voltage of each battery and the minimum single cell voltage; determining whether the voltage difference is greater than a preset voltage difference; if yes, the corresponding battery meets the first equalization trigger condition.

4. The method of claim 1, wherein, The method comprises the following steps: sampling and obtaining the residual capacity of each battery in the battery pack; determining the minimum residual capacity among the residual capacities of the batteries; calculating the residual capacity difference between the residual capacity of each battery and the minimum residual capacity; determining whether the residual capacity difference is greater than a preset capacity difference; if yes, the corresponding battery meets the first equalization trigger condition.

5. The method of claim 1, wherein, The method comprises the following steps: recording the serial number of the battery to be equalized; determining whether the number of the battery to be equalized is greater than the preset number; the preset number is half of the string number of the battery pack; if no, determining whether there are adjacent serial numbers of the battery to be equalized; if the number of the battery to be equalized is greater than the preset number or there are adjacent serial numbers of the battery to be equalized, the battery to be equalized is divided into a first battery group to be equalized and a second battery group to be equalized according to the serial number of the battery to be equalized by alternating allocation from small to large.

6. The method of claim 1, wherein, The equalization time proportion according to the preset equalization time and the first equalization trigger condition is used to sequentially equalize the two groups of battery packs to be equalized, including: According to the preset equalization time and the equalization time proportion of the first equalization trigger condition, a first heat dissipation time is obtained; According to the preset equalization time and the first heat dissipation time, the first battery pack to be equalized and the second battery pack to be equalized are sequentially equalized.

7. The method of claim 1, wherein, Also includes: According to the residual capacity of each battery to be equalized and the residual capacity threshold corresponding to the first equalization trigger condition, the residual capacity difference of each battery to be equalized is obtained; The maximum residual capacity difference of the two groups of battery packs to be equalized is obtained respectively; According to the preset equalization time, and the voltage section where the minimum single cell voltage is located, the corresponding single discharge amount is obtained; According to the preset equalization time, the maximum residual capacity difference, the corresponding single discharge amount and the equalization time proportion of the first equalization trigger condition, the total equalization time is obtained.

8. An electronic device, comprising: Including: At least one processor; At least one network interface, the network interface is in communication connection with the corresponding processor; And, The memory in communication connection with the at least one processor; wherein, The network interface is used to establish the communication connection between the processor and other external devices; The memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to execute the battery equalization control method according to any one of claims 1-7.

9. A non-transitory computer storage medium, comprising: The computer storage medium stores computer executable instructions, and the computer executable instructions are executed by one or more processors, so that the one or more processors execute the battery equalization control method according to any one of claims 1-7. The computer storage medium stores computer executable instructions, and the computer executable instructions are executed by one or more processors, so that the one or more processors execute the battery equalization control method according to any one of claims 1-7.

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