Lithium battery equalization method and device

Abstract

The invention discloses a lithium battery equalization method and device, and the method comprises the steps: monitoring the voltage of each single cell of a lithium battery under a charging condition of the lithium battery, and recording an ampere-hour integral value when the voltage of each single cell reaches a preset voltage threshold value; after the lithium battery is fully charged, according to the relationship between the voltage of all the single cells and a preset voltage threshold value, calculating the initial to-be-balanced electric quantity of each single cell in different scenes; according to a sorting difference value between the voltage sequence of all the single battery cells at the full charge moment and the sequence when the voltage of each single battery cell reaches a preset voltage threshold value, calculating a correction amount and correcting an initial to-be-balanced electric quantity; and according to the corrected to-be-equalized cell information and the corresponding to-be-equalized electric quantity, starting an equalization operation and updating an equalization state. Based on the ampere-hour integral value after the voltage of the single battery cell reaches the preset voltage threshold value, verification and correction are carried out by utilizing the single voltage sequence at the full charge moment, the battery cell needing to be balanced can be accurately identified, and the estimated electric quantity needing to be balanced is high in precision.

Description

Technical Field

[0001] This invention relates to the field of lithium battery technology, and in particular to a lithium battery balancing method and apparatus. Background Technology

[0002] The two most important steps in lithium battery balancing solutions are identifying the cells that need balancing and estimating the amount of charge that needs to be balanced. Common methods for identifying cells requiring balancing include: using a voltage threshold—balancing is triggered when any single cell reaches this threshold; identifying cells requiring balancing based on the difference between a single cell's voltage and the average or median voltage; and identifying cells requiring balancing based on their State of Charge (SOC). Common methods for estimating the amount of charge that needs to be balanced include: balancing for a fixed duration (simple and easy to implement); adjusting the balancing duration based on the voltage difference ratio; and controlling the SOC of each cell.

[0003] However, current lithium battery balancing solutions suffer from low precision, coarse control, and low balancing efficiency, making it difficult to achieve the balancing goal effectively. Summary of the Invention

[0004] This invention provides a lithium battery balancing method and apparatus to solve the problems of low precision, coarse control, low balancing efficiency, and difficulty in achieving high balancing targets in existing technologies.

[0005] According to one aspect of the present invention, a lithium battery equalization method is provided, comprising:

[0006] Under lithium battery charging conditions, monitor the voltage of each individual cell of the lithium battery and record the ampere-hour integral value when the voltage of each individual cell reaches the preset voltage threshold.

[0007] After the lithium battery is fully charged, the initial balance charge required for each individual cell is calculated according to the relationship between the voltage of all individual cells and the preset voltage threshold, depending on the scenario.

[0008] The correction amount and the initial balance required are calculated based on the difference between the voltage order of all individual cells at the moment of full charging and the order when the voltage of each individual cell reaches the preset voltage threshold.

[0009] The balancing operation is initiated and the balancing status is updated based on the corrected information on the cells requiring balancing and the corresponding amount of power to be balanced.

[0010] Optionally, during lithium battery charging, the voltage of each individual cell in the lithium battery is monitored, and the integral value of each individual cell's voltage in ampere-hours when it reaches a preset voltage threshold is recorded, including:

[0011] During lithium battery charging, the voltage of each individual cell in the lithium battery is monitored. When the voltage of the highest individual cell is greater than or equal to the preset voltage threshold, the ampere-hour integration is initiated.

[0012] Continue to monitor the voltage of each individual cell. When the voltage of the second individual cell is greater than or equal to the preset voltage threshold, record the ampere-hour integral value Ah2 at this time.

[0013] When the voltage of the nth individual cell is greater than or equal to the preset voltage threshold, the ampere-hour integral value Ahn is recorded at this time, where n is a positive integer greater than 2 and n ≤ the total number of lithium battery cells;

[0014] Continue charging until the lithium battery is fully charged, and record the ampere-hour integral value Ahf at the moment of full charge.

[0015] Optionally, after the lithium battery is fully charged, based on the relationship between the voltage of all individual cells and the preset voltage threshold, the initial balancing charge required for each individual cell is calculated for different scenarios, including:

[0016] After the lithium battery is fully charged, if the voltage of all individual cells is greater than or equal to the preset voltage threshold, the difference between the target balanced capacity and the preset capacity is calculated.

[0017] Based on the relationship between the ampere-hour integral value when the voltage of the nth individual cell is greater than or equal to the preset voltage threshold and the difference in charge, the cells that need to be balanced are identified and the initial charge that needs to be balanced for the cells is calculated.

[0018] Optionally, based on the relationship between the ampere-hour integral value when the voltage of the nth individual cell is ≥ the preset voltage threshold and the difference in charge, the cells that need to be balanced are identified and the initial charge to be balanced for the cells is calculated, including:

[0019] The integral value of ampere-hours when the voltage of the nth individual cell is greater than or equal to the preset voltage threshold is compared with the energy difference value;

[0020] If the ampere-hour integral value when the voltage of the nth individual cell is greater than or equal to the preset voltage threshold is less than or equal to the power difference value, then the nth individual cell does not need to be balanced.

[0021] If the ampere-hour integral value when the voltage of the nth individual cell is greater than the preset voltage threshold is greater than the energy difference value, then it is determined whether the ampere-hour integral values ​​when the voltage of other individual cells (excluding the nth individual cell) is greater than the preset voltage threshold satisfy Ahn-Ahi>Aht-ΔAh; where Ahn is the ampere-hour integral value when the voltage of the nth individual cell is greater than the preset voltage threshold, Ahi is the ampere-hour integral value when the voltage of the i-th individual cell is greater than the preset voltage threshold, Aht is the target balanced energy, ΔAh is the preset energy deviation, and i represents the number of any individual cell among the other individual cells (excluding the nth individual cell);

[0022] When the ampere-hour integral value of the i-th cell voltage is greater than or equal to the preset voltage threshold, and satisfies Ahn-Ahi > Aht-ΔAh, balancing is required. The initial balancing charge is Ahn-Ahi-(Aht-ΔAh).

[0023] Optionally, after the lithium battery is fully charged, the initial balancing charge required for each individual cell is calculated based on the relationship between the voltage of all individual cells and the preset voltage threshold, and the calculation is performed according to different scenarios.

[0024] After the lithium battery is fully charged, if the voltage of some individual cells is less than the preset voltage threshold, the difference between the target balanced capacity and the preset capacity is calculated.

[0025] Based on the relationship between the ampere-hour integral value at the moment of full charge and the difference in power, the cells that need to be balanced are identified and the initial power that needs to be balanced for the cells is calculated.

[0026] Optionally, based on the relationship between the ampere-hour integral value at the moment of full charging and the difference in charge level, the cells that need to be balanced are identified and the initial charge level to be balanced for the cells is calculated, including:

[0027] The ampere-hour integral value at the moment of full charging is compared with the power difference;

[0028] If the ampere-hour integral value at the moment of full charge is less than or equal to the power difference, then determine whether the ampere-hour integral value of other single cells whose voltage is greater than or equal to the preset voltage threshold satisfies Ahf-Ahi>Aht-2ΔAh.

[0029] When the integral value of Ah-hour when the voltage of the i-th individual cell is greater than or equal to the preset voltage threshold satisf, Ahf-Ahi>Aht-2ΔAh, balancing is required. The initial balancing charge is Ahf-Ahi-(Aht-2ΔAh).

[0030] If the ampere-hour integral value at the moment of full charge is greater than the power difference value, then determine whether the ampere-hour integral value of other single cells whose voltage is greater than or equal to the preset voltage threshold satisfies Ahf-Ahi>ΔAh.

[0031] When the ampere-hour integral value of the i-th individual cell voltage is greater than or equal to the preset voltage threshold, and Ahf - Ahi > ΔAh, balancing is required. The initial balancing charge is Ahf - Ahi - ΔAh, where Ahf is the ampere-hour integral value at full charge.

[0032] Optionally, based on the difference between the voltage order of all individual cells at the moment of full charging and the order in which the voltage of each individual cell reaches the preset voltage threshold, the correction amount and the correction of the initial balance charge include:

[0033] The voltage of all individual cells is sorted at full charge to obtain the voltage sorting results;

[0034] The voltage sorting results are compared with the order in which the voltages of each individual cell reach the preset voltage threshold. The sorting difference for each individual cell is calculated, and the correction amount and the initial equalization charge to be corrected are calculated as follows:

[0035] Correction amount = sorting difference / total number of cells to be balanced × maximum amount of charge to be balanced;

[0036] If the correction amount is less than or equal to 1% of the rated capacity, then no correction is required for the initial power balance.

[0037] If 1% of the rated capacity < correction amount ≤ 3% of the rated capacity, the correction amount is added to the initial balance amount for the voltage ranking result that is ranked higher; otherwise, the correction amount is subtracted from the initial balance amount.

[0038] If the correction amount is greater than 3% of the rated capacity, the cell is determined to be abnormal, the fault is reported, and the balancing operation for the cell is stopped.

[0039] Optionally, based on the corrected information on the cells requiring balancing and the corresponding amount of power to be balanced, the balancing operation can be initiated and the balancing status updated, including:

[0040] The corrected information on cells requiring equalization and the corresponding amount of energy to be equalized are stored in the battery management system, and the equalization operation is paused during the charging process after the highest single cell voltage is ≥ the preset voltage threshold.

[0041] After the lithium battery is fully charged, regardless of whether it is discharging, charging or in a dormant state, the equalization operation is initiated and the equalization status is updated based on the control of the battery management system.

[0042] Optionally, after the lithium battery is fully charged, regardless of whether it is in a discharging, charging, or dormant state, a balancing operation is initiated based on the battery management system control, and the balancing status is updated, including:

[0043] After the lithium battery is fully charged, when the battery management system is online, the already balanced charge of each cell that needs to be balanced is calculated.

[0044] Update the remaining power to be balanced based on the corrected power to be balanced and the power already balanced; where the power already balanced = balancing start time × balancing current, and the remaining power to be balanced = corrected power to be balanced - power already balanced.

[0045] After the lithium battery is fully charged, before the battery management system enters sleep mode, the balancing time is calculated; where, balancing time = remaining charge to be balanced / balancing current;

[0046] When the remaining balance charge of any cell to be balanced is 0 or the balance time is 0, the balancing operation on that cell is stopped until all cells to be balanced have stopped balancing or have resumed charging to full charge.

[0047] According to another aspect of the present invention, a lithium battery equalization device is provided, comprising:

[0048] The monitoring module is used to monitor the voltage of each individual cell of the lithium battery under the charging condition, and record the ampere-hour integral value when the voltage of each individual cell reaches a preset voltage threshold.

[0049] The initial balance charge calculation module is used to calculate the initial balance charge of each individual cell according to the relationship between the voltage of all individual cells and the preset voltage threshold after the lithium battery is fully charged, and to calculate the initial balance charge of each individual cell in different scenarios.

[0050] The calculation and correction module is used to calculate the correction amount and correct the initial balance charge based on the difference between the voltage order of all individual cells at the time of full charging and the order when the voltage of each individual cell reaches the preset voltage threshold.

[0051] The equalization control module is used to initiate the equalization operation and update the equalization status based on the corrected information of the cells to be equalized and the corresponding amount of power to be equalized.

[0052] This invention provides a lithium battery balancing method and apparatus. The method includes: monitoring the voltage of each individual cell in the lithium battery during charging, and recording the ampere-hour integral value of each individual cell when its voltage reaches a preset voltage threshold; after the lithium battery is fully charged, calculating the initial balancing charge of each individual cell according to the relationship between the voltage of all individual cells and the preset voltage threshold, categorized by scenario; calculating a correction amount and correcting the initial balancing charge based on the difference between the voltage order of all individual cells at full charge and the order in which the voltage of each individual cell reaches the preset voltage threshold; and initiating a balancing operation and updating the balancing state based on the corrected information of the cells to be balanced and the corresponding balancing charge. The technical solution provided by this invention, during lithium battery charging, utilizes the ampere-hour integral value of each individual cell after its voltage reaches the preset voltage threshold, and employs the individual cell voltage order at full charge for verification and correction. This balancing scheme can accurately identify the cells that need balancing, provides high accuracy in estimating the balancing charge, and enables balancing under all subsequent operating conditions after a single identification. It boasts high balancing efficiency and is applicable to various cell types.

[0053] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0054] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0055] Figure 1 A flowchart of a lithium battery balancing method provided in an embodiment of the present invention;

[0056] Figure 2 This is a schematic diagram illustrating the ampere-hour integral value of a lithium battery equalization method provided in an embodiment of the present invention when the voltage of each individual cell reaches a preset voltage threshold.

[0057] Figure 3 A flowchart of another lithium battery balancing method provided in an embodiment of the present invention;

[0058] Figure 4 This is a schematic diagram of the ampere-hour integral value under the scenario where the voltage of all individual cells is ≥ a preset voltage threshold during full charging, according to an embodiment of the present invention.

[0059] Figure 5 A flowchart of another lithium battery balancing method provided in an embodiment of the present invention;

[0060] Figure 6 This is a schematic diagram of the ampere-hour integral value in a scenario where the voltage of some individual cells is less than a preset voltage threshold during full charging, according to an embodiment of the present invention.

[0061] Figure 7 This is a schematic diagram of the structure of a lithium battery equalization device provided in an embodiment of the present invention;

[0062] Figure 8 This is a schematic diagram of an electronic device for a lithium battery balancing method provided in an embodiment of the present invention. Detailed Implementation

[0063] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0064] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0065] Figure 1 The flowchart illustrates a lithium battery balancing method provided in an embodiment of the present invention. This method can be executed by a lithium battery balancing device, which can be implemented in hardware and / or software and can be configured in any electronic device with communication capabilities. See also... Figure 1 The method includes:

[0066] S110. Under lithium battery charging conditions, monitor the voltage of each individual cell of the lithium battery and record the ampere-hour integral value when the voltage of each individual cell reaches the preset voltage threshold.

[0067] The preset voltage threshold is based on the voltage during the rapid rise phase at the end of the charging curve. Because the lithium battery charging process involves constant current charging followed by constant voltage charging, the voltage rises rapidly in the later stages of charging. At this point, the correlation between voltage and the remaining charge of the cell is clearer. Setting the voltage threshold at a specific point during this rapid rise phase ensures that when the voltage reaches the threshold, the cell is nearly fully charged, and its voltage effectively reflects the remaining charge. It should be noted that this step relies on the following two assumptions: ① All cells in the pack have similar capacities; ② All cells in the pack have similar internal resistances.

[0068] Specifically, since lithium batteries are typically composed of multiple individual cells connected in series / parallel to form a battery pack, the core requirement for balancing is to eliminate the difference in charge between individual cells. Therefore, it is necessary to monitor the voltage change of each individual cell in real time to determine whether it has reached a preset voltage threshold, and record the values ​​in the order in which the cell voltages reach the preset voltage threshold. For example, when the voltage of the first (highest) individual cell is greater than or equal to the preset voltage threshold, ampere-hour integration begins; when the voltage of the second individual cell is greater than or equal to the preset voltage threshold, the ampere-hour integration value at this time is recorded as Ah2; ... when the voltage of the nth individual cell is greater than or equal to the preset voltage threshold, it is recorded as Ahn; until the battery is fully charged, the final ampere-hour integration value Ahf is recorded.

[0069] S120. After the lithium battery is fully charged, calculate the initial balance charge required for each individual cell according to the relationship between the voltage of all individual cells and the preset voltage threshold, and calculate the initial balance charge required for each individual cell in different scenarios.

[0070] The initial balancing charge is a raw value calculated based on the assumption that "the cell capacity and internal resistance are similar", and is not the final balancing charge.

[0071] Specifically, after the lithium battery is fully charged, scenarios are divided based on whether the voltage of all individual cells has reached a preset voltage threshold. By identifying the cells that need to be balanced in different scenarios, the initial amount of energy to be balanced for those cells is calculated. For example, the first scenario is when the voltage of all individual cells has reached the preset voltage threshold, and the second scenario is when the voltage of some individual cells has not reached the preset voltage threshold. Different scenarios determine the calculation method for the initial amount of energy to be balanced and the values ​​of the parameters required in the calculation process.

[0072] S130. Calculate the correction amount and the initial equalization charge required for correction based on the difference between the voltage order of all individual cells at the moment of full charging and the order when the voltage of each individual cell reaches the preset voltage threshold.

[0073] Specifically, the calculation of the initial power to be balanced relies on two ideal assumptions:

[0074] ① All cells in the pack have similar capacities; ② All cells in the pack have similar internal resistances. Based on these two assumptions, we assume that the order in which cell voltages reach the preset voltage threshold equals the order in which the cells actually have the highest capacity. However, in practical applications, cell capacities and internal resistances inevitably differ. These differences will cause the order in which cell voltages reach the preset voltage threshold to be inconsistent with the order in which the cells actually have the highest capacity, thus introducing errors in the initial calculation of the required equalization capacity. Therefore, it is necessary to use the order of individual cell voltages at full charge to verify and correct the initial required equalization capacity.

[0075] The order in which cell voltages reach the preset voltage threshold refers to the order in which the voltages of each individual cell first reach the preset voltage threshold during the charging process (e.g., cell A reaches the threshold first, cell B reaches the threshold third). The voltage order of all individual cells at full charge refers to the order in which the voltages of all individual cells are ranked from high to low (or from low to high) when the lithium battery is fully charged (e.g., cell B ranks first in full charge voltage, cell A ranks fourth). The ranking difference refers to the difference in position of the same cell in the above two rankings, calculated as: Ranking difference = "ranking of the cell at full charge voltage" - "ranking of the cell at threshold".

[0076] After step S120 has identified the total number of cells requiring balancing, and considering the largest initial balancing charge among all cells, a correction amount is calculated based on the ranking difference, the total number of cells requiring balancing, and the maximum initial balancing charge. This correction amount is then adjusted based on the correction amount and a preset percentage of the rated capacity. For example, if the correction amount is ≤1% of the rated capacity, the initial balancing charge is not adjusted; if 1% of the rated capacity < correction amount ≤3% of the rated capacity, and the cells with the full-charge voltage ranking higher than the threshold are ranked higher, the initial balancing charge is increased by the correction amount; otherwise, the correction amount is decreased; if the correction amount is >3% of the rated capacity, a "cell abnormality" report is submitted, and balancing is stopped.

[0077] S140. Based on the corrected information of the cells to be balanced and the corresponding amount of power to be balanced, start the balancing operation and update the balancing status.

[0078] The information on cells requiring balancing includes which cells need balancing, their cell numbers, and their locations; the corresponding amount of power to be balanced specifies how much power each cell needs to be adjusted.

[0079] Specifically, the corrected information on the cells requiring balancing and the corresponding amount of energy to be balanced are stored in the battery management system. The battery management system then initiates the balancing operation and updates the balancing status based on the corrected information on the cells requiring balancing and the corresponding amount of energy to be balanced.

[0080] The technical solution provided by this invention, under lithium battery charging conditions, is a balancing scheme based on the ampere-hour integral value after the voltage of a single cell reaches a preset voltage threshold, and using the single cell voltage sorting at full charge time for verification and correction. This scheme can accurately identify the cells that need to be balanced, and the estimated amount of charge to be balanced is highly accurate. After one identification, balancing can be performed under all subsequent operating conditions, with high balancing efficiency, and it is applicable to a variety of different cell types.

[0081] Optionally, during lithium battery charging, the voltage of each individual cell in the lithium battery is monitored, and the integral value of each individual cell's voltage in ampere-hours when it reaches a preset voltage threshold is recorded, including:

[0082] During lithium battery charging, the voltage of each individual cell in the lithium battery is monitored. When the highest voltage of a single cell is greater than or equal to a preset voltage threshold, ampere-hour integration is initiated. The voltage of each individual cell is monitored continuously. When the voltage of the second individual cell is greater than or equal to the preset voltage threshold, the ampere-hour integration value Ah2 is recorded. When the voltage of the nth individual cell is greater than or equal to the preset voltage threshold, the ampere-hour integration value Ahn is recorded, where n is a positive integer greater than 2 and n ≤ the total number of lithium battery cells. Charging continues until the lithium battery is fully charged, and the ampere-hour integration value Ahf is recorded at the moment of full charge.

[0083] For example, see Figure 2 , Figure 2 This is a schematic diagram illustrating the ampere-hour integral value of a lithium battery equalization method provided in an embodiment of the present invention when the voltage of each individual cell reaches a preset voltage threshold.

[0084] Figure 3 This is a flowchart of another lithium battery balancing method provided by an embodiment of the present invention. The embodiments of the present invention further refine the aforementioned embodiments based on the previous embodiments. Optionally, step S120 specifically includes:

[0085] S210. After the lithium battery is fully charged, if the voltage of all individual cells is ≥ the preset voltage threshold, calculate the difference between the target balanced capacity and the preset capacity.

[0086] The target equalization capacity can be set according to the battery pack's capacity consistency requirements and the inherent characteristics of the cells. The target equalization capacity is usually set to 1%-5% of the rated capacity. The preset capacity deviation can be preset according to the error between the ampere-hour integral and the monitored individual cell voltage. Usually, the preset capacity deviation needs to cover the error between the ampere-hour integral and the monitored individual cell voltage.

[0087] S220. Based on the relationship between the ampere-hour integral value when the voltage of the nth individual cell is greater than or equal to the preset voltage threshold and the difference in charge, identify the cells that need to be balanced and calculate the initial charge that needs to be balanced for the cells.

[0088] Specifically, the ampere-hour integral value when the voltage of the nth individual cell is greater than or equal to a preset voltage threshold is compared with the energy difference. If the ampere-hour integral value when the voltage of the nth individual cell is greater than or equal to the energy difference, then the nth individual cell does not need to be balanced. If the ampere-hour integral value when the voltage of the nth individual cell is greater than or equal to the preset voltage threshold, then it is determined whether the ampere-hour integral values ​​when the voltage of other individual cells (excluding the nth individual cell) is greater than or equal to the preset voltage threshold satisfy Ahn-Ahi>Aht-ΔAh; where Ahn Here, Ai is the ampere-hour integral value when the voltage of the nth individual cell is greater than or equal to a preset voltage threshold, Ai is the ampere-hour integral value when the voltage of the i-th individual cell is greater than or equal to a preset voltage threshold, Aht is the target equalization capacity, ΔAh is the preset capacity deviation, and i represents the number of any individual cell other than the nth individual cell. Equalization is required when the ampere-hour integral value when the voltage of the i-th individual cell is greater than or equal to the preset voltage threshold satisfies Ahn - Ahi > Aht - ΔAh, and the initial equalization capacity is Ahn - Ahi - (At - ΔAh). See details... Figure 4 , Figure 4 This is a schematic diagram of the ampere-hour integral value under the scenario where the voltage of all individual cells is ≥ a preset voltage threshold during full charging, as provided in an embodiment of the present invention.

[0089] In scenario ① where all individual cell voltages are ≥ preset voltage threshold during full charging, the nth individual cell is the last (or latest batch) cell to reach the preset voltage threshold during the charging process, and its corresponding ampere-hour integral value Ahn is the largest ampere-hour integral value among all cells that reach the preset voltage threshold—this characteristic is the core basis for subsequent judgments, stemming from the key assumption of the scheme:

[0090] Assuming that all cells in the pack have similar capacity and internal resistance, the order in which the cell voltage reaches the voltage threshold is equal to the order in which the cell's charge is: that is, the cell that reaches the threshold first (such as the 1st and 2nd cells) has less charge (Ahi is smaller) and a higher charge; the cell that reaches the threshold later (such as the nth cell) has more charge (Ahn is larger) and a lower charge.

[0091] Therefore, the ampere-hour integral value Ahn of the nth individual cell reaching the preset voltage threshold is essentially the lowest energy benchmark among all cells reaching the threshold—it represents the integral level of the normal cell with the lowest energy. All cells that reach the voltage threshold before it have higher energy levels. Therefore, choosing whether Ahn is greater than Aht-ΔAh as the criterion is essentially using Ahn's lowest energy benchmark attribute to achieve a single judgment covering all cells, directly reflecting the maximum energy difference, thus avoiding redundant calculations. In summary, identifying cells requiring balancing by selecting the relationship between Ahn and Aht-ΔAh of the nth cell essentially achieves the goal of a single judgment covering the entire cell and accurately selecting those requiring balancing by locking the lowest energy benchmark—solving the problems of coarse judgment and high misjudgment rate in traditional solutions, improving efficiency by simplifying calculations, and adapting to various cell types.

[0092] Figure 5 This is a flowchart illustrating another lithium battery balancing method provided by an embodiment of the present invention. The embodiments of the present invention further refine the aforementioned embodiments based on the previous ones. See also... Figure 5 Step S120 further includes:

[0093] S310. After the lithium battery is fully charged, if the voltage of some individual cells is less than the preset voltage threshold, calculate the difference between the target balanced capacity and the preset capacity.

[0094] S320. Based on the relationship between the ampere-hour integral value and the difference in charge at the moment of full charge, identify the cells that need to be balanced and calculate the initial charge that the cells need to be balanced.

[0095] Specifically, the ampere-hour integral value at the moment of full charging is compared with the energy difference. If the ampere-hour integral value at the moment of full charging is less than or equal to the energy difference, it is determined whether the ampere-hour integral values ​​of other individual cells (excluding the cell corresponding to the ampere-hour integral value at the moment of full charging) when their voltage is greater than or equal to a preset voltage threshold satisfy Ahf - Ahi > Aht - 2ΔAh. When the ampere-hour integral value of the i-th individual cell when its voltage is greater than or equal to the preset voltage threshold satisfies Ahf - Ahi > Aht - 2ΔAh, balancing is required, and the initial balancing capacity is Ahf - A. hi-(Aht-2ΔAh); If the ampere-hour integral value at the moment of full charging is greater than the energy difference, then determine whether the ampere-hour integral values ​​of other individual cells whose voltages are ≥ preset voltage thresholds (excluding the individual cell corresponding to the ampere-hour integral value at the moment of full charging) satisfy Ahf-Ahi>ΔAh; When the ampere-hour integral value of the i-th individual cell whose voltage is ≥ preset voltage threshold satisfies Ahf-Ahi>ΔAh, balancing is required, and the initial balancing energy = Ahf-Ahi-ΔAh; where Ahf is the ampere-hour integral value at the moment of full charging. See details. Figure 6 , Figure 6 This is a schematic diagram of the ampere-hour integral value under the scenario where the voltage of some individual cells is less than a preset voltage threshold during full charging, as provided in an embodiment of the present invention.

[0096] In scenario ②, where some cell voltages are lower than the preset voltage threshold during full charging, the logic of threshold attainment order equaling battery capacity order in the traditional scenario ① completely fails—cells that haven't reached the threshold lack the ampere-hour integral value for voltage reaching the preset threshold, making it impossible to determine battery capacity based on the threshold attainment order; moreover, these cells have significantly lower battery capacity. In this case, the ampere-hour integral value Ahf at full charging becomes the only feasible unified benchmark: Ahf is the total charged capacity integral of the entire battery pack during full charging, representing the maximum chargeable capacity of the entire battery pack. Regardless of whether a cell reaches the voltage threshold, its actual battery capacity can be measured by the difference between Ahf and the threshold—cells reaching the threshold have nearly full capacity, while cells not reaching the threshold have far less than full capacity. Ahf covers the battery capacity comparison needs of all cells. Therefore, choosing Ahf as the benchmark fills the gap of lacking data for cells that haven't reached the threshold; its judgment logic adapts to real-world issues such as lithium battery aging, poor consistency, and integral errors, ensuring balanced identification with no omissions, high accuracy, and low overhead.

[0097] In some other embodiments, optionally, step S130 specifically includes:

[0098] At full charge, the voltages of all individual cells are sorted to obtain the voltage sorting results. The voltage sorting results are compared with the order in which the voltages of each individual cell reach the preset voltage threshold. The sorting difference for each individual cell is calculated, and the correction amount and the initial equalization charge to be corrected are calculated as follows:

[0099] Correction amount = sorting difference / total number of cells to be balanced × maximum amount of power to be balanced

[0100] If the correction amount is less than or equal to 1% of the rated capacity, then no correction is required for the initial power balance.

[0101] If 1% of the rated capacity < correction amount ≤ 3% of the rated capacity, the correction amount is added to the initial balance amount for the voltage ranking result that is ranked higher; otherwise, the correction amount is subtracted from the initial balance amount.

[0102] If the correction amount is greater than 3% of the rated capacity, the cell is determined to be abnormal, the fault is reported, and the balancing operation for the cell is stopped.

[0103] In some other embodiments, optionally, step S140 specifically includes:

[0104] The corrected information on cells requiring equalization and the corresponding amount of energy to be equalized are stored in the battery management system. The equalization operation is paused during the charging process when the highest single cell voltage is greater than or equal to the preset voltage threshold. After the lithium battery is fully charged, the equalization operation is started under the control of the battery management system, regardless of whether it is discharging, charging or dormant. The equalization status is also updated.

[0105] Specifically, after the lithium battery is fully charged, when the battery management system is online, the already balanced charge of each cell to be balanced is calculated; based on the corrected charge to be balanced and the already balanced charge, the remaining charge to be balanced is updated; where the already balanced charge = balancing start time × balancing current, and the remaining charge to be balanced = corrected charge to be balanced - already balanced charge; after the lithium battery is fully charged, before the battery management system enters sleep mode, the balancing time is calculated; where the balancing time = remaining charge to be balanced / balancing current; the balancing time is written into the analog front end (AFE), and after sleep mode, the AFE can automatically count down. When the remaining charge to be balanced of any cell is 0 or the balancing time is 0, the balancing operation of that cell is stopped until all cells to be balanced have stopped balancing or have re-entered the charging state to full charge.

[0106] The technical solution provided by this invention, which is based on the ampere-hour integral value after the cell voltage reaches a preset voltage threshold and uses the cell voltage sorting at full charge time for verification and correction, does not require extensive testing and calibration before application, thus saving resources; it can accurately identify the cells that need to be balanced and the estimated amount of charge to be balanced is highly accurate; after one identification, it can be balanced under all subsequent operating conditions, with high balancing efficiency and is applicable to various battery types; it can improve battery pack consistency and increase battery utilization.

[0107] Figure 7 This is a schematic diagram of a lithium battery balancing device provided in an embodiment of the present invention. See also: Figure 7 The device includes a monitoring module 710, an initial power balance calculation module 720, a calculation and correction module 730, and a balance control module 740.

[0108] The monitoring module 710 is used to monitor the voltage of each individual cell of the lithium battery during the lithium battery charging process, and record the ampere-hour integral value when the voltage of each individual cell reaches a preset voltage threshold.

[0109] The initial balance charge calculation module 720 is used to calculate the initial balance charge of each individual cell according to the relationship between the voltage of all individual cells and the preset voltage threshold after the lithium battery is fully charged, and to calculate the initial balance charge of each individual cell in different scenarios.

[0110] The calculation and correction module 730 is used to calculate the correction amount and the initial equalization charge required for correction based on the difference between the voltage order of all individual cells at the time of full charging and the order when the voltage of each individual cell reaches the preset voltage threshold.

[0111] The equalization control module 740 is used to initiate the equalization operation and update the equalization status based on the corrected information of the cells to be equalized and the corresponding amount of power to be equalized.

[0112] The lithium battery balancing device provided in the embodiments of the present invention can execute the lithium battery balancing method provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the method.

[0113] Figure 8 This is a schematic diagram of an electronic device for an embodiment of a lithium battery balancing method provided by the present invention. The electronic device is intended to represent various forms of digital computers, such as laptops, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframes, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices (e.g., helmets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

[0114] like Figure 8As shown, the electronic device 10 includes at least one processor 11 and a memory, such as a read-only memory (ROM) 12 or a random access memory (RAM) 13, communicatively connected to the at least one processor 11. The memory stores computer programs executable by the at least one processor. The processor 11 can perform various appropriate actions and processes based on the computer program stored in the ROM 12 or loaded from storage unit 18 into the RAM 13. The RAM 13 can also store various programs and data required for the operation of the electronic device 10. The processor 11, ROM 12, and RAM 13 are interconnected via a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0115] Multiple components in electronic device 10 are connected to I / O interface 15, including: input unit 16, such as keyboard, mouse, etc.; output unit 17, such as various types of displays, speakers, etc.; storage unit 18, such as disk, optical disk, etc.; and communication unit 19, such as network card, modem, wireless transceiver, etc. Communication unit 19 allows electronic device 10 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0116] Processor 11 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. Processor 11 performs the various methods and processes described above, such as a lithium battery balancing method.

[0117] In some embodiments, the lithium battery balancing method may be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or installed on electronic device 10 via ROM 12 and / or communication unit 19. When the computer program is loaded into RAM 13 and executed by processor 11, one or more steps of the lithium battery balancing method described above may be performed. Alternatively, in other embodiments, processor 11 may be configured to perform the lithium battery balancing method by any other suitable means (e.g., by means of firmware).

[0118] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0119] Computer programs used to implement the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the processor, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be performed. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0120] In the context of this invention, a computer-readable storage medium can be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, apparatus, or device. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0121] To provide interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the electronic device. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0122] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as data servers), or middleware components (e.g., application servers), or frontend components (e.g., user computers with graphical user interfaces or web browsers through which users can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., communication networks). Examples of communication networks include local area networks (LANs), wide area networks (WANs), blockchain networks, and the Internet.

[0123] A computing system can include clients and servers. Clients and servers are generally located far apart and typically interact through communication networks. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a hosting product within the cloud computing service system to address the shortcomings of traditional physical hosts and VPS services, such as high management difficulty and weak business scalability.

[0124] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0125] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A lithium battery equalization method, characterized in that, include: Under lithium battery charging conditions, monitor the voltage of each individual cell of the lithium battery and record the ampere-hour integral value when the voltage of each individual cell reaches the preset voltage threshold. After the lithium battery is fully charged, the initial balance charge required for each individual cell is calculated according to the relationship between the voltage of all individual cells and the preset voltage threshold, depending on the scenario. The correction amount and the initial balance required are calculated based on the difference between the voltage order of all individual cells at the moment of full charging and the order when the voltage of each individual cell reaches the preset voltage threshold. The balancing operation is initiated and the balancing status is updated based on the corrected information on the cells requiring balancing and the corresponding amount of power to be balanced.

2. The lithium battery equalization method according to claim 1, characterized in that, During lithium battery charging, the voltage of each individual cell in the lithium battery is monitored, and the integral ampere-hour value of each individual cell when its voltage reaches a preset voltage threshold is recorded, including: During lithium battery charging, the voltage of each individual cell in the lithium battery is monitored. When the voltage of the highest individual cell is greater than or equal to the preset voltage threshold, the ampere-hour integration is initiated. Continue to monitor the voltage of each individual cell. When the voltage of the second individual cell is greater than or equal to the preset voltage threshold, record the ampere-hour integral value Ah2 at this time. When the voltage of the nth individual cell is greater than or equal to the preset voltage threshold, the ampere-hour integral value Ahn is recorded at this time, where n is a positive integer greater than 2 and n ≤ the total number of lithium battery cells; Continue charging until the lithium battery is fully charged, and record the ampere-hour integral value Ahf at the moment of full charge.

3. The lithium battery balancing method according to claim 2, characterized in that, After the lithium battery is fully charged, based on the relationship between the voltage of all individual cells and the preset voltage threshold, the initial balancing charge required for each individual cell is calculated for different scenarios, including: After the lithium battery is fully charged, if the voltage of all individual cells is greater than or equal to the preset voltage threshold, the difference between the target balanced capacity and the preset capacity is calculated. Based on the relationship between the ampere-hour integral value when the voltage of the nth individual cell is greater than or equal to the preset voltage threshold and the difference in charge, the cells that need to be balanced are identified and the initial charge that needs to be balanced for the cells is calculated.

4. The lithium battery balancing method according to claim 3, characterized in that, Based on the relationship between the ampere-hour integral value when the voltage of the nth individual cell is greater than or equal to the preset voltage threshold and the difference in charge, the cells that need to be balanced are identified and the initial charge to be balanced for the cells is calculated, including: The integral value of ampere-hours when the voltage of the nth individual cell is greater than or equal to the preset voltage threshold is compared with the energy difference value; If the ampere-hour integral value when the voltage of the nth individual cell is greater than or equal to the preset voltage threshold is less than or equal to the power difference value, then the nth individual cell does not need to be balanced. If the ampere-hour integral value when the voltage of the nth individual cell is greater than the preset voltage threshold is greater than the energy difference value, then it is determined whether the ampere-hour integral values ​​when the voltage of other individual cells (excluding the nth individual cell) is greater than the preset voltage threshold satisfy Ahn-Ahi>Aht-ΔAh; where Ahn is the ampere-hour integral value when the voltage of the nth individual cell is greater than the preset voltage threshold, Ahi is the ampere-hour integral value when the voltage of the i-th individual cell is greater than the preset voltage threshold, Aht is the target balanced energy, ΔAh is the preset energy deviation, and i represents the number of any individual cell among the other individual cells (excluding the nth individual cell); When the ampere-hour integral value of the i-th cell voltage is greater than or equal to the preset voltage threshold, and satisfies Ahn-Ahi > Aht-ΔAh, balancing is required. The initial balancing charge is Ahn-Ahi-(Aht-ΔAh).

5. The lithium battery equalization method according to claim 2, characterized in that, After the lithium battery is fully charged, based on the relationship between the voltage of all individual cells and the preset voltage threshold, the initial balancing capacity required for each individual cell is calculated for different scenarios, including: After the lithium battery is fully charged, if the voltage of some individual cells is less than the preset voltage threshold, the difference between the target balanced capacity and the preset capacity is calculated. Based on the relationship between the ampere-hour integral value at the moment of full charge and the difference in power, the cells that need to be balanced are identified and the initial power that needs to be balanced for the cells is calculated.

6. The lithium battery balancing method according to claim 5, characterized in that, Based on the relationship between the ampere-hour integral value at the moment of full charge and the difference in charge level, the cells that need to be balanced are identified and the initial charge level to be balanced for each cell is calculated, including: The ampere-hour integral value at the moment of full charging is compared with the power difference; If the ampere-hour integral value at the moment of full charge is less than or equal to the power difference, then determine whether the ampere-hour integral value of other single cells whose voltage is greater than or equal to the preset voltage threshold satisfies Ahf-Ahi>Aht-2ΔAh. When the integral value of Ah-hour when the voltage of the i-th individual cell is greater than or equal to the preset voltage threshold satisf, Ahf-Ahi>Aht-2ΔAh, balancing is required. The initial balancing charge is Ahf-Ahi-(Aht-2ΔAh). If the ampere-hour integral value at the moment of full charge is greater than the power difference value, then determine whether the ampere-hour integral value of other single cells whose voltage is greater than or equal to the preset voltage threshold satisfies Ahf-Ahi>ΔAh. When the ampere-hour integral value of the i-th individual cell voltage is greater than or equal to the preset voltage threshold, and Ahf - Ahi > ΔAh, balancing is required. The initial balancing charge is Ahf - Ahi - ΔAh, where Ahf is the ampere-hour integral value at full charge.

7. The lithium battery balancing method according to claim 1, characterized in that, Based on the difference between the voltage order of all individual cells at full charge and the order in which the voltage of each individual cell reaches the preset voltage threshold, the correction amount and the correction of the initial balance required include: The voltage of all individual cells is sorted at full charge to obtain the voltage sorting results; The voltage sorting results are compared with the order in which the voltages of each individual cell reach the preset voltage threshold. The sorting difference for each individual cell is calculated, and the correction amount and the initial equalization charge to be corrected are calculated as follows: Correction amount = sorting difference / total number of cells to be balanced × maximum amount of charge to be balanced; If the correction amount is less than or equal to 1% of the rated capacity, then no correction is required for the initial power balance. If 1% of the rated capacity < correction amount ≤ 3% of the rated capacity, the correction amount is added to the initial balance amount for the voltage ranking result that is ranked higher; otherwise, the correction amount is subtracted from the initial balance amount. If the correction amount is greater than 3% of the rated capacity, the cell is determined to be abnormal, the fault is reported, and the balancing operation for the cell is stopped.

8. The lithium battery balancing method according to claim 1, characterized in that, Based on the corrected information on the cells requiring balancing and the corresponding amount of power requiring balancing, the balancing operation is initiated and the balancing status is updated, including: The corrected information on cells requiring equalization and the corresponding amount of energy to be equalized are stored in the battery management system, and the equalization operation is paused during the charging process after the highest single cell voltage is ≥ the preset voltage threshold. After the lithium battery is fully charged, regardless of whether it is discharging, charging or in a dormant state, the equalization operation is initiated and the equalization status is updated based on the control of the battery management system.

9. The lithium battery balancing method according to claim 8, characterized in that, After the lithium battery is fully charged, regardless of whether it is in a discharging, charging, or dormant state, the battery management system will control the balancing operation to start and update the balancing status, including: After the lithium battery is fully charged, when the battery management system is online, the already balanced charge of each cell that needs to be balanced is calculated. Update the remaining power to be balanced based on the corrected power to be balanced and the power already balanced; where the power already balanced = balancing start time × balancing current, and the remaining power to be balanced = corrected power to be balanced - power already balanced. After the lithium battery is fully charged, before the battery management system enters sleep mode, the balancing time is calculated; where, balancing time = remaining charge to be balanced / balancing current; When the remaining balance charge of any cell to be balanced is 0 or the balance time is 0, the balancing operation on that cell is stopped until all cells to be balanced have stopped balancing or have resumed charging to full charge.

10. A lithium battery balancing device, characterized in that, include: The monitoring module is used to monitor the voltage of each individual cell of the lithium battery under the charging condition, and record the ampere-hour integral value when the voltage of each individual cell reaches a preset voltage threshold. The initial balance charge calculation module is used to calculate the initial balance charge of each individual cell according to the relationship between the voltage of all individual cells and the preset voltage threshold after the lithium battery is fully charged, and to calculate the initial balance charge of each individual cell in different scenarios. The calculation and correction module is used to calculate the correction amount and correct the initial balance charge based on the difference between the voltage order of all individual cells at the time of full charging and the order when the voltage of each individual cell reaches the preset voltage threshold. The equalization control module is used to initiate the equalization operation and update the equalization status based on the corrected information of the cells to be equalized and the corresponding amount of power to be equalized.

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