Battery cell capacity balancing method and device, computer equipment, storage medium and program product

Abstract

The invention relates to the technical field of battery cell capacity balancing, in particular to a battery cell capacity balancing method and device, computer equipment, a storage medium and a program product. Acquiring charging data of each battery cell in the target battery in the charging process; according to the charging data corresponding to each battery cell, determining a charging voltage inflection point corresponding to each battery cell in the charging process; calculating the current available capacity corresponding to each battery cell according to the charging voltage inflection point corresponding to each battery cell; and balancing the capacity of each battery cell according to the current available capacity corresponding to each battery cell. And the capacity of each battery cell is balanced, so that the capacity balance of each battery cell in the target battery is ensured. The method does not depend on the accuracy of SOC and SOH, so that the effect of balancing the capacities of the battery cells in the target battery is better, and the service life of the target battery can be ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of battery cell capacity balancing, and in particular to a battery cell capacity balancing method, device, computer equipment, storage medium and program product. Background Art

[0002] Cell balancing technology stems from the performance differences between cells in a battery pack due to manufacturing differences, aging, and inconsistent usage conditions. This is one of the core functions of the battery management system (BMS). It adjusts the state of charge of each cell in an active or passive manner to avoid damage to the overall performance and life due to overcharging or over-discharging of a single cell. Active balancing can achieve efficient transfer of energy between cells, rather than an energy dissipative design, which is more energy-efficient than passive balancing. With the popularization of electric vehicles and energy storage technology, cell balancing technology is developing towards higher efficiency and intelligence to meet the needs of high-performance battery systems.

[0003] In the prior art, cell balancing solutions are mostly based on the estimated SOC (State of Charge) and SOH (State of Health) values ​​of each cell, and use this to calculate the precise balancing capacity of each cell. This solution is too dependent on the accuracy of SOC and SOH. When SOC and SOH are not corrected for a long time or the SOC and SOH are calculated inaccurately, the balancing effect is poor. Summary of the invention

[0004] In view of this, the present invention provides a method, device, computer equipment, storage medium and program product for balancing the capacity of battery cells to solve the problem of how to balance the capacity of battery cells.

[0005] In a first aspect, the present invention provides a method for balancing the capacity of a battery cell, the method comprising:

[0006] Obtain charging data of each cell in the target battery during the charging process;

[0007] According to the charging data corresponding to each battery cell, determine the charging voltage inflection point corresponding to each battery cell during the charging process;

[0008] Calculate the current available capacity of each battery cell according to the charging voltage inflection point of each battery cell;

[0009] The capacity of each battery cell is balanced according to the current available capacity corresponding to each battery cell.

[0010] The cell capacity balancing method provided in the embodiment of the present application obtains the charging data of each cell in the target battery during the charging process; according to the charging data corresponding to each cell, the charging voltage inflection point corresponding to each cell during the charging process is determined, thereby ensuring the accuracy of the determined charging voltage inflection point corresponding to each cell during the charging process. According to the charging voltage inflection point corresponding to each cell, the current available capacity corresponding to each cell is calculated, thereby ensuring the accuracy of the calculated current available capacity corresponding to each cell. According to the current available capacity corresponding to each cell, the capacity of each cell is balanced, thereby ensuring the capacity balance of each cell in the target battery. In the above method, the charging voltage inflection point corresponding to each cell is calculated to calculate the current available capacity corresponding to each cell, thereby eliminating the short board effect. Unlike the prior art, the actual available capacity of each cell is not calculated according to the SOC and SOH of each cell. Specifically, the actual available capacity of the cell = the rated capacity of the cell * the SOC of the cell * the SOH of the cell. If there is an error in the SOC and SOH, the actual available capacity of the cell will be inaccurately calculated, affecting the accuracy of the balance. The above method bypasses the precise SOC and SOH values ​​of each battery cell and directly calculates the actual available capacity of each battery cell based on the inflection point method. It does not rely on the accuracy of SOC and SOH, avoids the problem of poor battery balancing due to inaccurate SOC and SOH, and further ensures that the capacity balancing effect of each battery cell in the target battery is better, thereby improving the accuracy and reliability of battery cell capacity balancing.

[0011] In an optional implementation, the charging data includes state of charge data, voltage data, and current data. According to the charging data corresponding to each battery cell, determining the charging voltage inflection point corresponding to each battery cell during the charging process includes:

[0012] Identify state of charge data;

[0013] If the state of charge data is within the preset state of charge range, the voltage data and current data of each battery cell during the charging process are obtained;

[0014] According to the voltage data and current data, the charging voltage inflection point corresponding to each battery cell during the charging process is determined.

[0015] In an optional implementation, determining a charging voltage inflection point corresponding to each battery cell during the charging process according to each voltage data and each current data includes:

[0016] For each battery cell, a capacity increment curve corresponding to the battery cell is generated according to the voltage data corresponding to the battery cell and the capacitance increment after integrating the current data. The capacity increment curve is used to characterize the change in battery cell capacity corresponding to each unit voltage change of the battery cell;

[0017] Determine the minimum point in the capacity increment curve;

[0018] The minimum point is determined as the charging voltage inflection point corresponding to the battery cell during the charging process.

[0019] In an optional implementation, the charging data includes charging end time and charging current data, and according to the charging voltage inflection point corresponding to each battery cell, the current available capacity corresponding to each battery cell is calculated, including:

[0020] Determine the target inflection point time corresponding to each battery cell, the target inflection point time includes the time when the battery cell is at the charging voltage inflection point;

[0021] Obtaining a first available capacity of each battery cell corresponding to a target inflection point;

[0022] The second available capacity of each battery cell is calculated by multiplying the current data by the time difference between the target inflection point moment of each battery cell and the lowest inflection point moment of the battery cell with the lowest voltage;

[0023] The current available capacity of each battery cell is calculated by adding the first available capacity to the second available capacity.

[0024] In an optional implementation, the charging data includes voltage data; each battery cell includes a first battery cell for which a charging voltage inflection point is detected and a second battery cell for which a charging voltage inflection point is not detected, and determining a target inflection point moment corresponding to each battery cell includes:

[0025] Based on the voltage data corresponding to each battery cell, sorting each first battery cell and second battery cell;

[0026] According to the arrangement order of the first battery cells and the second battery cells, the target inflection point moments corresponding to the first battery cells are used to perform interpolation calculations on the second battery cells to obtain the target inflection point moments corresponding to the second battery cells, wherein the target inflection point moment of the first battery cell is the moment when the charging voltage inflection point is detected.

[0027] In an optional implementation, the capacity of each battery cell is balanced according to the current available capacity corresponding to each battery cell, including:

[0028] Calculating a first difference between a current available capacity corresponding to each battery cell and a minimum current available capacity;

[0029] For the third battery cell, if the first difference is greater than the first preset difference threshold, a second difference between the first difference and the first preset difference threshold is calculated, and the third battery cell is controlled to release the capacity of the second difference, and the third battery cell is any battery cell among the battery cells.

[0030] In an optional implementation, the capacity of each battery cell is balanced according to the current available capacity corresponding to each battery cell, including:

[0031] Calculate the average available capacity corresponding to the current available capacity of each battery cell;

[0032] For the fourth battery cell, a third difference is calculated by subtracting the average available capacity from the current available capacity corresponding to the fourth battery cell;

[0033] If the third difference is greater than the second preset difference threshold, a fourth difference between the third difference and the second preset difference threshold is calculated, and the fourth battery cell is controlled to discharge the capacity of the fourth difference to the energy storage component of the active balancing circuit;

[0034] If the third difference is less than the third preset difference threshold, a fifth difference between the third preset difference threshold and the third difference is calculated, and the energy storage component of the active balancing circuit is controlled to charge the fourth battery cell with a capacity of the fifth difference, the fourth battery cell being any one of the battery cells, and the second preset difference threshold being greater than the third preset difference threshold.

[0035] In a second aspect, the present invention provides a cell capacity balancing device, the device comprising:

[0036] An acquisition module is used to acquire charging data of each cell in the target battery during the charging process;

[0037] A determination module, used to determine the charging voltage inflection point corresponding to each battery cell during the charging process according to the charging data corresponding to each battery cell;

[0038] A calculation module, used to calculate the current available capacity of each battery cell according to the charging voltage inflection point of each battery cell;

[0039] The capacity balancing module is used to balance the capacity of each battery cell according to the current available capacity corresponding to each battery cell.

[0040] The cell capacity balancing device provided in the embodiment of the present application obtains the charging data of each cell in the target battery during the charging process; according to the charging data corresponding to each cell, the charging voltage inflection point corresponding to each cell during the charging process is determined, thereby ensuring the accuracy of the determined charging voltage inflection point corresponding to each cell during the charging process. According to the charging voltage inflection point corresponding to each cell, the current available capacity corresponding to each cell is calculated, thereby ensuring the accuracy of the calculated current available capacity corresponding to each cell. According to the current available capacity corresponding to each cell, the capacity of each cell is balanced, thereby ensuring the capacity balance of each cell in the target battery. In the above method, the charging voltage inflection point corresponding to each cell is calculated to calculate the current available capacity corresponding to each cell, thereby eliminating the short board effect. Unlike the prior art, the actual available capacity of each cell is not calculated according to the SOC and SOH of each cell. Specifically, the actual available capacity of the cell = the rated capacity of the cell * the SOC of the cell * the SOH of the cell. If there is an error in the SOC and SOH, the actual available capacity of the cell will be inaccurately calculated, affecting the accuracy of the balance. The above method bypasses the precise SOC and SOH values ​​of each battery cell and directly calculates the actual available capacity of each battery cell based on the inflection point method. It does not rely on the accuracy of SOC and SOH, avoids the problem of poor battery balancing due to inaccurate SOC and SOH, and further ensures that the capacity balancing effect of each battery cell in the target battery is better, thereby improving the accuracy and reliability of battery cell capacity balancing.

[0041] In a third aspect, the present invention provides a computer device, comprising: a memory and a processor, the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the battery cell capacity balancing method of the first aspect or any corresponding embodiment thereof by executing the computer instructions.

[0042] In a fourth aspect, the present invention provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to enable a computer to execute the cell capacity balancing method of the first aspect or any corresponding embodiment thereof.

[0043] In a fifth aspect, the present invention provides a computer program product, comprising computer instructions for causing a computer to execute the cell capacity balancing method of the first aspect or any corresponding embodiment thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0045] Figure 1 is a schematic flow chart of a cell capacity balancing method according to an embodiment of the present invention;

[0046] Figure 2 is a schematic diagram of charging voltage curves of batteries with different aging degrees according to an embodiment of the present invention;

[0047] Figure 3 is a schematic diagram of the distribution of charging inflection points of cells with different aging degrees according to an embodiment of the present invention;

[0048] Figure 4 is a flow chart of another cell capacity balancing method according to an embodiment of the present invention;

[0049] Figure 5 is a schematic diagram of a capacity increment curve of a battery cell charged according to an embodiment of the present invention;

[0050] Figure 6 is a comparison diagram of charging voltage curves of battery cells with different aging degrees and capacity increment curves of battery cells charged according to an embodiment of the present invention;

[0051] Figure 7 is a schematic flow chart of another method for balancing battery cell capacity according to an embodiment of the present invention;

[0052] Figure 8 is a flow chart of another cell capacity balancing method according to an embodiment of the present invention;

[0053] Fig. 9 is a structural block diagram of a cell capacity balancing device according to an embodiment of the present invention;

[0054] Fig.10 It is a schematic diagram of the hardware structure of a computer device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0056] It should be noted that the method for cell capacity balancing provided in the embodiment of the present application may be implemented by a cell capacity balancing device, which may be implemented by software, hardware, or a combination of software and hardware to become part or all of a computer device, wherein the computer device may be a server or a terminal, wherein the server in the embodiment of the present application may be a single server or a server cluster composed of multiple servers, and the terminal in the embodiment of the present application may be a car computer, a smart phone, a personal computer, a tablet computer, a wearable device, an intelligent robot, and other intelligent hardware devices. In the following method embodiments, the execution subject is an electronic device as an example for explanation.

[0057] According to an embodiment of the present invention, an embodiment of a method for balancing the capacity of a battery cell is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0058] In this embodiment, a cell capacity balancing method is provided, which can be used in the above-mentioned electronic device. Figure 1 is a flow chart of a cell capacity balancing method according to an embodiment of the present invention. Figure 1 As shown, the process includes the following steps:

[0059] Step S101, acquiring charging data of each cell in a target battery during the charging process.

[0060] Specifically, the electronic device can control the charging device to charge the target battery, and then the electronic device monitors the target battery during the charging process of the target battery, thereby obtaining the charging data of each battery cell in the target battery during the charging process. The target battery is a power battery, energy storage battery, backup power supply, etc. composed of multiple batteries connected in series, and the type of the target battery can be a lithium iron phosphate battery.

[0061] Step S102, determining a charging voltage inflection point corresponding to each battery cell during the charging process according to charging data corresponding to each battery cell.

[0062] Specifically, the charging data may include voltage data and current data. The electronic device may obtain the voltage data and current data of each battery cell during the charging process. Then, the collected voltage data and current data are analyzed to generate a voltage curve showing the change of voltage data with charging capacity. When the target battery is charged with constant current, the voltage curve may also be a curve showing the change of voltage data with charging time.

[0063] The voltage curve is exemplified below by taking a lithium iron phosphate battery as an example. Figure 2 When charging lithium iron phosphate batteries at a constant current, the voltage curves of cells with different aging degrees are shown, where: Figure 2 The number on the lower right side indicates the number of cycles of the battery; Figure 2 It can be seen that when charging at a constant current, the voltage curve of the lithium iron phosphate battery cell has two obvious voltage platform areas, where the platform with a lower voltage (battery cell SOC∈(30%-60%)) is called the first charging voltage platform area of ​​the battery cell, and the platform with a higher voltage (battery cell SOC∈(65%-90%)) is called the second charging voltage platform area of ​​the battery cell. Between the first charging voltage platform area and the second charging voltage platform area of ​​the battery cell, the rising slope dV / dQ of the battery cell charging voltage is larger, and the rising slope dV / dQ of the battery cell voltage shows a trend of first increasing and then decreasing, and the point where the rising slope dV / dQ of the battery cell voltage is the largest is called the charging voltage inflection point of the battery cell.

[0064] Therefore, after determining the voltage curve, the slope corresponding to each point in the voltage curve can be calculated, and then the point with the maximum slope between the first charging voltage platform area and the second charging voltage platform area of ​​the charging voltage can be determined as the charging voltage inflection point.

[0065] Step S103, calculating the current available capacity corresponding to each battery cell according to the charging voltage inflection point corresponding to each battery cell.

[0066] Specifically, the electronic device can determine the charging time corresponding to each charging voltage inflection point according to the charging voltage inflection point corresponding to each battery cell, and then calculate the current available capacity corresponding to each battery cell according to the charging time corresponding to the charging voltage inflection point.

[0067] This step will be described in detail below.

[0068] Step S104 , balancing the capacities of the battery cells according to the currently available capacities corresponding to the battery cells.

[0069] Specifically, the electronic device may use a preset capacity balancing strategy to balance the capacity of each battery cell according to the current available capacity corresponding to each battery cell.

[0070] The cell capacity balancing method provided in the embodiment of the present application obtains the charging data of each cell in the target battery during the charging process; according to the charging data corresponding to each cell, the charging voltage inflection point corresponding to each cell during the charging process is determined, thereby ensuring the accuracy of the determined charging voltage inflection point corresponding to each cell during the charging process. According to the charging voltage inflection point corresponding to each cell, the current available capacity corresponding to each cell is calculated, thereby ensuring the accuracy of the calculated current available capacity corresponding to each cell. According to the current available capacity corresponding to each cell, the capacity of each cell is balanced, thereby ensuring the capacity balance of each cell in the target battery. In the above method, the charging voltage inflection point corresponding to each cell is calculated to calculate the current available capacity corresponding to each cell, thereby eliminating the short board effect. Unlike the prior art, the actual available capacity of each cell is not calculated according to the SOC and SOH of each cell. Specifically, the actual available capacity of the cell = the rated capacity of the cell * the SOC of the cell * the SOH of the cell. If there is an error in the SOC and SOH, the actual available capacity of the cell will be inaccurately calculated, affecting the accuracy of the balance. The above method bypasses the precise SOC and SOH values ​​of each battery cell and directly calculates the actual available capacity of each battery cell based on the inflection point method. It does not rely on the accuracy of SOC and SOH, avoids the problem of poor battery balancing due to inaccurate SOC and SOH, and further ensures that the capacity balancing effect of each battery cell in the target battery is better, thereby improving the accuracy and reliability of battery cell capacity balancing.

[0071] In this embodiment, a cell capacity balancing method is provided, which can be used in the above-mentioned electronic device. Figure 4 is a flow chart of a cell capacity balancing method according to an embodiment of the present invention. Figure 4 As shown, the process includes the following steps:

[0072] Step S201, obtaining charging data of each cell in the target battery during the charging process.

[0073] For details about this step, please refer to the above description of step S101, which will not be described in detail here.

[0074] Step S202, determining a charging voltage inflection point corresponding to each battery cell during the charging process according to charging data corresponding to each battery cell.

[0075] Specifically, the charging data includes state of charge data, voltage data, and current data. The above step S202 may include the following steps:

[0076] Step S2021, identifying the state of charge data.

[0077] Specifically, the electronic device can obtain the state of charge data corresponding to each battery cell in real time during the charging process of the target battery.

[0078] Then, the electronic device identifies the charge state data corresponding to each battery cell.

[0079] Step S2022: If the state of charge data is within the preset state of charge range, the voltage data and current data of each battery cell during the charging process are obtained.

[0080] Specifically, the electronic device can obtain a preset state of charge range input by a user, or receive a preset state of charge range sent by other devices, or obtain cell attribute information corresponding to each cell of the target battery, and then set the preset state of charge range based on the cell attribute information corresponding to each cell.

[0081] The embodiment of the present application does not specifically limit the manner in which the electronic device obtains the preset state of charge range.

[0082] Exemplarily, the electronic device may determine the charging platform area corresponding to each battery cell according to the property information of each battery cell corresponding to the target battery, and then set a preset state of charge range according to the charging platform area corresponding to each battery cell.

[0083] Taking the above-mentioned lithium iron phosphate battery with the first charging voltage platform area SOC∈(30%-60%) and the second charging voltage platform area SOC∈(65%-90%) as an example, the preset state of charge range ∈(40%-80%) is set, or is (50%-70%). The embodiment of the present application does not specifically limit the preset state of charge range.

[0084] Then, the electronic device can compare the state of charge data corresponding to the battery cell with the minimum and maximum values ​​in the preset state of charge range to detect whether the state of charge data of each battery cell is within the preset state of charge range. If the state of charge data of each battery cell is within the preset state of charge range, the electronic device can obtain the voltage data and current data of each battery cell during the charging process.

[0085] Step S2023, determining the charging voltage inflection point corresponding to each battery cell during the charging process according to each voltage data and each current data.

[0086] Specifically, the above step S2023 may include the following steps:

[0087] Step a1: for each battery cell, generate a capacity increment curve corresponding to the battery cell according to the voltage data corresponding to the battery cell and the capacitance increment after integrating the current data.

[0088] Among them, the capacity increment curve is used to characterize the change in cell capacity corresponding to each unit change in cell voltage, wherein the cell capacity can be obtained by integrating the current data over time.

[0089] Specifically, for each battery cell, the electronic device can generate a capacity increment curve corresponding to the battery cell according to the voltage data and current data corresponding to the battery cell, wherein the abscissa of the capacity increment curve is the voltage data, and the ordinate is the battery cell capacity increment data dQ / dV.

[0090] It should be noted that in actual engineering applications, the sampling accuracy of the cell voltage is mostly 1mV, and the voltage change amplitude is very small while the charging capacity change is very large during the process of the charging voltage rising from the first charging voltage platform area to the second charging voltage platform area. The calculated dV / dQ amplitude is very small and sometimes 0, making it difficult to accurately identify the inflection point. Figure 5 As shown, the electronic device can generate a capacity increment curve dQ / dV (battery capacity increment change corresponding to each unit voltage change) corresponding to the battery cell according to the voltage data and current data corresponding to the battery cell.

[0091] Step a2, determine the minimum point in the capacity increment curve.

[0092] Specifically, the electronic device can identify the capacity increment curve and determine the minimum value point in the capacity increment curve.

[0093] For example, Figure 6 As shown, the charging voltage inflection point between the first and second voltage platforms is the point where the cell voltage slope dV / dQ is the largest, and this point is also the point where the capacity increment curve dQ / dV is the smallest. The charging voltage inflection point that needs to be identified is located between the first and second voltage platforms, that is, within the preset state of charge range, and its corresponding capacity increment minimum point is located between the two capacity increment peaks.

[0094] In addition, it should be noted that since the voltage may fluctuate during the charging process, the sampled voltage curve needs to be filtered to remove points where the voltage rises and falls abnormally, so as to avoid errors in identifying the minimum value of dQ / dV. At the same time, the influence of data below the first voltage platform area and above the second voltage platform area on the inflection point identification is avoided. Before identifying dQ / dV, the battery cell SOC is judged first, and identification is performed only when the battery cell SOC is within the preset charge state range.

[0095] Step a3, determining the minimum point as the charging voltage inflection point corresponding to the battery cell during the charging process.

[0096] Specifically, the electronic device may determine the minimum value point as the charging voltage inflection point corresponding to the battery cell during the charging process.

[0097] Step S203, calculating the current available capacity corresponding to each battery cell according to the charging voltage inflection point corresponding to each battery cell.

[0098] For details about this step, please refer to the above description of step S103, which will not be elaborated here.

[0099] Step S204 , balancing the capacities of the battery cells according to the currently available capacities corresponding to the battery cells.

[0100] For details about this step, please refer to the above description of step S104, which will not be repeated here.

[0101] The cell capacity balancing method provided in the embodiment of the present application identifies the state of charge data; if the state of charge data is within the preset state of charge range, the voltage data and current data of each cell during the charging process are obtained, and the charging voltage inflection point corresponding to each cell during the charging process is determined based on each voltage data and each current data, thereby ensuring that the charging voltage inflection point corresponding to each cell during the charging process is between the first / second voltage platform. For each cell, a capacity increment curve corresponding to the cell is generated based on the voltage data and current data corresponding to the cell, so that the cell capacity change corresponding to each cell per unit voltage change can be determined based on the capacity increment curve. Determine the minimum point in the capacity increment curve; determine the minimum point as the charging voltage inflection point corresponding to the cell during the charging process, thereby ensuring that the determined charging voltage inflection point has the smallest cell capacity change corresponding to each unit voltage change, thereby determining that the cell has an inflection point during the charging process.

[0102] In this embodiment, a cell capacity balancing method is provided, which can be used in the above-mentioned electronic device. Figure 7 is a flow chart of a cell capacity balancing method according to an embodiment of the present invention. Figure 7 As shown, the process includes the following steps:

[0103] Step S301, acquiring charging data of each cell in the target battery during the charging process.

[0104] For details about this step, please refer to the above description of step S201, which will not be elaborated here.

[0105] Step S302, determining the charging voltage inflection point corresponding to each battery cell during the charging process according to the charging data corresponding to each battery cell.

[0106] For details about this step, please refer to the above description of step S202, which will not be elaborated here.

[0107] Step S303, calculating the current available capacity corresponding to each battery cell according to the charging voltage inflection point corresponding to each battery cell.

[0108] Specifically, the charging data includes the charging end time and the charging current data. The above step S303 may include the following steps:

[0109] Step S3031, determining the target inflection point time corresponding to each battery cell.

[0110] The target inflection point moment includes the moment when the battery cell is at a charging voltage inflection point. Each battery cell includes a first battery cell having a charging voltage inflection point detected. In an optional embodiment of the present application, the electronic device can determine each charging voltage inflection point as a target inflection point moment corresponding to the first battery cell based on the charging voltage inflection point corresponding to each first battery cell.

[0111] The electronic device can obtain the voltage data corresponding to each first battery cell, and then compare the voltage data corresponding to each first battery cell, and then determine the target battery cell with the smallest voltage value from each first battery cell according to the comparison result. The target inflection point time corresponding to each first battery cell is recorded until the target inflection point time corresponding to the target battery cell is obtained.

[0112] In an optional embodiment, if the state of charge data corresponding to the target cell exceeds the maximum value in the preset state of charge range, the electronic device also starts to count the number of first cells at the target inflection point moment. Alternatively, after the target cell identifies the target inflection point moment, the electronic device also starts to count the number of first cells at the target inflection point moment.

[0113] It should be noted that if the charging voltage inflection point of each battery cell is detected, the target inflection point moment of each battery cell is the actual recorded moment when the charging voltage inflection point is detected; if some battery cells have detected their charging voltage inflection points and some battery cells have not detected their charging voltage inflection points, then the battery cells that have not detected the charging voltage inflection points can determine their target inflection point moments through the target inflection point moments and voltage data of the battery cells that have detected the charging voltage inflection points.

[0114] Exemplarily, the charging data includes voltage data; each battery cell includes a first battery cell for which a charging voltage inflection point is detected and a second battery cell for which a charging voltage inflection point is not detected. The above step S3031 may include the following steps:

[0115] Step b1, sorting the first battery cells and the second battery cells based on the voltage data corresponding to the battery cells.

[0116] Optionally, the electronic device may sort the first battery cells and the second battery cells in descending order of the voltage data based on the voltage data corresponding to the battery cells.

[0117] Optionally, the electronic device may sort the first battery cells and the second battery cells in ascending order of the voltage data based on the voltage data corresponding to the battery cells.

[0118] Step b2: according to the arrangement order of the first battery cells and the second battery cells, using the target inflection point moments corresponding to the first battery cells, interpolation calculation is performed on the second battery cells to obtain the target inflection point moments corresponding to the second battery cells.

[0119] The target inflection point of the first cell is the moment when the charging voltage inflection point is detected. For example, if cell 1 identifies that the corresponding dQ / dV is the minimum when the voltage is V1, the middle time point of the V1 voltage platform is recorded as the target inflection point time t1 of cell 1; if cell 2 identifies that the corresponding dQ / dV is the minimum when the voltage is V1 and V1+1mV, the moment when the voltage platform rises from V1 to V1+1mV is recorded as the target inflection point time t2 of cell 2.

[0120] According to the arrangement order of the first battery cells and the second battery cells, a preset interpolation method is used to interpolate the target inflection point moments corresponding to the second battery cells based on the target inflection point moments corresponding to the first battery cells to obtain the target inflection point moments corresponding to the second battery cells.

[0121] Among them, the preset interpolation method may include a median interpolation method, a Newton interpolation method, a Jacobi interpolation method, or other interpolation methods. The embodiment of the present application does not specifically limit the preset interpolation method.

[0122] Exemplarily, for each second battery cell, the virtual inflection point moment corresponding to each second battery cell is determined according to the relationship between the voltage corresponding to each second battery cell and the voltage corresponding to each first battery cell. For example, the voltage of battery cell No. 5 is only lower than that of battery cell No. 6 and only higher than that of battery cell No. 3, and the real inflection point moments of battery cells No. 3 / 6 have been identified as t3 and t6 respectively, then t5=(t3+t6) / 2.

[0123] In order to ensure the accuracy of the target inflection point corresponding to the second battery cell, sufficient parameters of the first battery cell are required for difference calculation. Based on this, before step b1, the electronic device can determine the preset threshold value according to the number of battery cells in the target battery. Exemplarily, the electronic device can multiply the number of battery cells in the target battery by the preset proportion, wherein the preset proportion can be 70% or 65%. The embodiment of the present application limits the preset proportion.

[0124] Then the number of first cells is compared with a preset threshold value. If the number of first cells is greater than the preset threshold value, the electronic device can interpolate and calculate each second cell using each target inflection point moment corresponding to each first cell to obtain the target inflection point moment corresponding to each second cell. If the number of first cells is less than or equal to the preset threshold value, the electronic device waits for the next target battery charging process.

[0125] Exemplarily, the electronic device records the target inflection point moments identified by each first battery cell in sequence until the target battery cell with the lowest voltage identifies the target inflection point moment, thereby ending the identification process; the target inflection point moments t1, t2, …, tk corresponding to each first battery cell are obtained; when the number of first battery cells> the total number of battery cells*2 / 3, the identification is considered successful.

[0126] Step S3032, obtaining the first available capacity of each battery cell corresponding to the target inflection point.

[0127] Specifically, the electronic device may measure the first available capacity of each battery cell corresponding to the target inflection point.

[0128] It should be noted that, supported by the theory of experimental results, when the temperature of the target battery is constant and within the allowable error range, the first available capacity of each cell at the target inflection point is the same.

[0129] For example, Figure 2 The voltage curves for charging cells with different degrees of aging, as well as the positions of their inflection points, Figure 3 for Figure 2 This is a partial enlarged view of the distribution of charging inflection points of cells with different aging degrees. Figure 2 and Figure 3 It can be seen that within the allowable error range, the capacity decay of the battery cell during aging only occurs after the inflection point, and the capacity does not change from the moment when the power is 0 to the target inflection point. Figure 3 It can be seen that the error of the target inflection point moment corresponding to each battery cell is only 0.2%. Calculated based on the rated capacity Cn, the first available capacity value corresponding to the moment when the power is 0 to the target inflection point moment is approximately Cn*61.1%=C0. That is, the first available capacity corresponding to the battery cell at the target inflection point moment is Cn*61.1%=C0. For the convenience of calculation, in the embodiment of the present application, C0 can be used as the first available capacity of all battery cells.

[0130] Step S3033, the second available capacity of each battery cell is calculated by multiplying the current data by the time difference between the target inflection point moment and the lowest inflection point moment corresponding to the battery cell with the lowest voltage.

[0131] Specifically, the electronic device can calculate the second available capacity of each battery cell by multiplying the current data by the time difference between the target inflection point moment corresponding to each battery cell and the lowest inflection point moment corresponding to the battery cell with the lowest voltage identified.

[0132] Step S3034: The current available capacity of each battery cell is calculated by adding the first available capacity to the second available capacity.

[0133] Specifically, the electronic device may calculate the current available capacity corresponding to each battery cell by adding the first available capacity to the second available capacity.

[0134] Exemplarily, the battery is charged to time t, and at time t, target inflection point times of k battery cells are identified as t1, t2, ..., tk respectively.

[0135] The charging capacity of the first battery cell after the charging voltage inflection point is the charging capacity C1 from t1 to t, and the total available capacity is C0+C1;

[0136] The charging capacity of the second battery cell after the charging voltage inflection point is the charging capacity C2 from t2 to t, and the total available capacity is C0+C2;

[0137] The charging capacity of the kth battery cell after the charging voltage inflection point is the charging capacity Ck from time tk to time t, and the total available capacity is C0+Ck.

[0138] Among them, the electronic device determines that the operating condition of the charging voltage inflection point corresponding to each battery cell during the charging process is AC charging and the current is fixed and is I, and the integrated capacity of each battery cell from the target inflection point to the current moment is: C1=(t-t1)*I, C2=(t-t2)*I,…, Ck=(t-tk)*I.

[0139] Step S304: Capacity balancing of each battery cell is performed according to the current available capacity corresponding to each battery cell.

[0140] For details about this step, please refer to the above description of step S204, which will not be elaborated here.

[0141] The cell capacity balancing method provided in the embodiment of the present application sorts each first cell and second cell based on the voltage data corresponding to each cell; according to the arrangement order of each first cell and second cell, each target inflection point moment corresponding to each first cell is used to interpolate and calculate each second cell to obtain the target inflection point moment corresponding to each second cell. The first available capacity corresponding to each cell at the target inflection point moment is obtained; the second available capacity corresponding to each cell is calculated by multiplying the current data by the time difference between the target inflection point moment and the lowest inflection point moment corresponding to the cell with the lowest voltage identified, thereby ensuring the accuracy of the calculated second available capacity. The current available capacity corresponding to each cell calculated by adding the first available capacity to the second available capacity does not need to rely on the accuracy of SOC and SOH, thereby avoiding the inaccuracy of the calculated current available capacity due to the inaccuracy of SOC and SOH.

[0142] In this embodiment, a cell capacity balancing method is provided, which can be used in the above-mentioned electronic device. Figure 8 is a flow chart of a cell capacity balancing method according to an embodiment of the present invention. Figure 8 As shown, the process includes the following steps:

[0143] Step S401, acquiring charging data of each cell in the target battery during the charging process.

[0144] For details about this step, please refer to the above description of step S301, which will not be elaborated here.

[0145] Step S402, determining a charging voltage inflection point corresponding to each battery cell during the charging process according to charging data corresponding to each battery cell.

[0146] For details about this step, please refer to the above description of step S302, which will not be repeated here.

[0147] Step S403, calculating the current available capacity corresponding to each battery cell according to the charging voltage inflection point corresponding to each battery cell.

[0148] For details about this step, please refer to the above description of step S303, which will not be elaborated here.

[0149] Step S404: Capacity balancing of each battery cell is performed according to the current available capacity corresponding to each battery cell.

[0150] In another optional implementation manner of the present application, the above step S404 may include the following steps:

[0151] Step S4041, calculating a first difference between the current available capacity corresponding to each battery cell and the minimum current available capacity.

[0152] Specifically, the electronic device may compare the current available capacities corresponding to the respective battery cells and determine the minimum current available capacity from the respective current available capacities according to the comparison result.

[0153] Then, the electronic device may calculate a first difference between the current available capacity corresponding to each battery cell and the minimum current available capacity.

[0154] Exemplarily, the first difference may be calculated using the following formula: Cx-Cmin; wherein Cx is the current available capacity corresponding to each battery cell, and Cmin is the minimum current available capacity.

[0155] Step S4042: for the third battery cell, if the first difference is greater than the first preset difference threshold, a second difference between the first difference and the first preset difference threshold is calculated, and the third battery cell is controlled to release a capacity of the second difference.

[0156] The third battery cell is any one of the battery cells.

[0157] Specifically, the electronic device may receive a first preset difference threshold value input by a user, or may receive a first preset difference threshold value sent by other devices, or may set the first preset difference threshold value according to the first difference value. For example, the electronic device may add the first difference values ​​corresponding to each battery cell, and then calculate the average value to obtain the first preset difference threshold value.

[0158] The embodiment of the present application does not specifically limit the manner in which the electronic device obtains the first preset difference threshold.

[0159] Then, the electronic device compares the first difference with a first preset difference threshold.

[0160] If the first difference is greater than the first preset difference threshold, the electronic device obtains the second difference by subtracting the first preset difference threshold from the first difference.

[0161] The electronic device can identify the hardware structure corresponding to the target battery and detect whether there is a power storage component in the hardware structure corresponding to the target battery. If there is no capacitor storage component, it is determined that the preset capacity balancing strategy corresponding to the target battery is a passive balancing strategy, and the electronic device controls the third battery cell to release the capacity of the second difference.

[0162] Among them, the passive balancing strategy usually adopts the method of connecting a resistor in parallel to each battery cell. When the battery cell voltage exceeds the set threshold, the resistor is turned on and the excess energy is consumed to achieve voltage balancing. This method is relatively simple, but the efficiency is low and energy loss will occur.

[0163] Optionally, if the first difference is less than or equal to a first preset difference threshold, the battery cell is not controlled to release the battery capacity.

[0164] Exemplarily, if the first preset difference threshold is 2*Er, if Cx-Cmin-2*Er>0, balanced discharge is started, and the discharge capacity of the battery cell is Cx-Cmin-2*Er; if the battery cell has Cx-Cmin-2*Er≤0, balancing is not started, where Cx is the current available capacity corresponding to each battery cell, and Cmin is the minimum current available capacity.

[0165] In another optional implementation manner of the present application, the above step S404 may further include the following steps:

[0166] Step S4043, calculating the average available capacity corresponding to the current available capacity of each battery cell.

[0167] Specifically, the electronic device may add up the current available capacities corresponding to the battery cells, and then perform an average calculation to obtain the average available capacity.

[0168] Step S4044: For the fourth battery cell, a third difference is calculated by subtracting the average available capacity from the current available capacity corresponding to the fourth battery cell.

[0169] Specifically, for the fourth battery cell, the electronic device may calculate the third difference by subtracting the average available capacity from the current available capacity corresponding to the fourth battery cell.

[0170] Step S4045: if the third difference is greater than the second preset difference threshold, a fourth difference between the third difference and the second preset difference threshold is calculated, and the fourth battery cell is controlled to discharge the capacity of the fourth difference to the energy storage component of the active balancing circuit.

[0171] Specifically, the electronic device can receive a second preset difference input by a user, or a second preset difference sent by other devices, and can also set the second preset difference according to the third difference. Among them, exemplarily, the electronic device can add the third differences corresponding to each battery cell, and then calculate the average, and then the electronic device multiplies the calculated average by the first weight to obtain the second preset difference threshold. Optionally, the first weight can be less than 1, and the first weight can be greater than 1. The embodiment of the present application does not specifically limit the first weight. Among them, it should be noted that the second preset difference threshold is a positive number.

[0172] The embodiment of the present application does not specifically limit the manner in which the electronic device obtains the second preset difference threshold.

[0173] Then, the electronic device compares the third difference with the second preset difference threshold.

[0174] If the third difference is greater than the second preset difference threshold, the electronic device can identify the hardware structure corresponding to the target battery, detect whether there is a power storage component in the hardware structure corresponding to the target battery, and if there is a capacitor storage component, determine that the preset capacity balancing strategy corresponding to the target battery is an active balancing strategy. Among them, the active balancing strategy achieves voltage balancing by energy transfer. Specific energy transfer methods include capacitive, inductive, transformer, etc. The active balancing circuit is relatively complex, but has high efficiency and can reduce energy loss.

[0175] Among them, the active balancing strategy achieves voltage balancing through energy transfer. Specific energy transfer methods include capacitor type, inductor type, transformer type, etc. The active balancing circuit is relatively complex, but it is highly efficient and can reduce energy loss.

[0176] Then, the electronic device calculates a fourth difference between the third difference and the second preset difference threshold, and controls the fourth battery cell to discharge the capacity of the fourth difference to the energy storage component of the active balancing circuit.

[0177] Step S4046: if the third difference is less than the third preset difference threshold, a fifth difference between the third preset difference threshold and the third difference is calculated, and the energy storage component of the active balancing circuit is controlled to charge the fourth battery cell with a capacity of the fifth difference.

[0178] The fourth battery cell is any battery cell among the battery cells, and the second preset difference threshold is greater than the third preset difference threshold.

[0179] Specifically, the electronic device can receive the third preset difference input by the user, can also receive the third preset difference sent by other devices, or can set the third preset difference according to the third difference. Among them, by way of example, the electronic device can add the third differences corresponding to each battery cell, then calculate the average, and then the electronic device multiplies the calculated average value by the first weight to obtain the second preset difference threshold. Optionally, the first weight can be less than 1 or greater than 1. The embodiments of the present application do not make specific limitations on the first weight. It should be noted that the third preset difference threshold is negative.

[0180] Specifically, if the third difference is less than the third preset difference threshold, the electronic device calculates the fifth difference between the third preset difference threshold and the third difference. The energy storage component of the active equalization circuit is controlled to charge the fourth battery cell with the capacity of the fifth difference.

[0181] By way of example, denote the average available capacity as Cmean = (C1 + C2 + … + Ck) / k; Dr is the second preset difference range. Dr is a positive number.

[0182] If Cx - Cmean - Dr > 0, the electronic device controls the battery cell to release the battery capacity to the capacitance storage component of the target battery, and the released battery capacity of the fourth difference is Cx - Cmean - Dr.

[0183] If Cmean - Cx - Dr > 0, the electronic device can control the capacitance storage component to supplement the battery cell with the battery capacity of the fifth difference, and the supplemented battery capacity of the fifth difference is Cmean - Cx - Dr.

[0184] For the battery cells with |Cx - Cmean| < Dr, charging or discharging of the battery cells is prohibited.

[0185] In an optional implementation manner of the battery cell capacity equalization method provided by the embodiments of the present application, the first difference between the current available capacity corresponding to each battery cell and the minimum current available capacity is calculated, so that the equalization degree between the current available capacities corresponding to the current battery cells can be determined according to the first difference. For the third battery cell, if the first difference is greater than the first preset difference threshold, the second difference between the first difference and the first preset difference threshold is calculated, and the third battery cell is controlled to release the capacity of the second difference, so that the current available capacity of the third battery cell can be reduced, and further the capacity equalization between the battery cells in the target battery can be ensured.

[0186] In an optional embodiment, the average available capacity corresponding to the current available capacity corresponding to each battery cell is calculated; for the fourth battery cell, the current available capacity corresponding to the fourth battery cell is subtracted from the average available capacity to calculate the third difference, so that the difference between the current available capacity and the average available capacity of each fourth battery cell can be determined, and then the capacity between each fourth battery cell can be balanced according to the third difference. If the third difference is greater than the second preset difference threshold, the fourth difference between the third difference and the second preset difference threshold is calculated, and the fourth battery cell is controlled to release the capacity of the fourth difference to the energy storage component of the active balancing circuit, so that the current available capacity of each fourth battery cell can be reduced, and the capacity of the fourth difference released by the fourth battery cell is stored, avoiding the waste of capacity resources. If the third difference is less than the third preset difference threshold, the fifth difference between the third preset difference threshold and the third difference is calculated, and the energy storage component of the active balancing circuit is controlled to charge the fourth battery cell with the current of the fifth difference, so that the current available capacity of each fourth battery cell can be increased, thereby ensuring the capacity balance between each fourth battery cell.

[0187] In this embodiment, a cell capacity balancing device is also provided, which is used to implement the above-mentioned embodiments and preferred embodiments, and will not be repeated here. As used below, the term "module" can implement a combination of software and / or hardware for a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0188] This embodiment provides a battery cell capacity balancing device, such as Fig. 9 As shown, including:

[0189] An acquisition module 501 is used to acquire charging data of each cell in a target battery during a charging process;

[0190] A determination module 502 is used to determine a charging voltage inflection point corresponding to each battery cell during the charging process according to charging data corresponding to each battery cell;

[0191] A calculation module 503 is used to calculate the current available capacity corresponding to each battery cell according to the charging voltage inflection point corresponding to each battery cell;

[0192] The capacity balancing module 504 is used to balance the capacity of each battery cell according to the current available capacity corresponding to each battery cell.

[0193] The further functional description of each of the above modules and units is the same as that of the above corresponding embodiments and will not be repeated here.

[0194] The cell capacity balancing device in this embodiment is presented in the form of a functional unit, where the unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that executes one or more software or fixed programs, and / or other devices that can provide the above functions.

[0195] The embodiment of the present invention also provides a computer device having the above Fig. 9 The cell capacity balancing device shown.

[0196] See also Fig.10 , Fig.10 is a schematic diagram of the structure of a computer device provided by an optional embodiment of the present invention, such as Fig.10 As shown, the computer device includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. Various components are connected to each other using different buses for communication, and can be installed on a common mainboard or installed in other ways as needed. The processor can process the instructions executed in the computer device, including instructions stored in or on the memory to display the graphical information of the GUI on an external input / output device (such as, a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple computer devices can be connected, and each device provides some necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Fig.10 A processor 10 is taken as an example.

[0197] The processor 10 may be a central processing unit, a network processor or a combination thereof. The processor 10 may further include a hardware chip. The hardware chip may be a dedicated integrated circuit, a programmable logic device or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic or any combination thereof.

[0198] The memory 20 stores instructions executable by at least one processor 10, so that at least one processor 10 executes the method shown in the above embodiment.

[0199] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function; the data storage area may store data created according to the use of the computer device, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some optional embodiments, the memory 20 may optionally include a memory remotely arranged relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0200] The memory 20 may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid state drive; the memory 20 may also include a combination of the above types of memory.

[0201] The computer device also includes an input device 30 and an output device 40. The processor 10, the memory 20, the input device 30 and the output device 40 may be connected via a bus or other means. Fig.10 The example of connecting through bus is taken in the following.

[0202] The input device 30 can receive input digital or character information, and generate key signal input related to the user settings and function control of the computer device, such as a touch screen, a keypad, a mouse, a track pad, a touch pad, an indicator bar, one or more mouse buttons, a trackball, a joystick, etc. The output device 40 may include a display device, an auxiliary lighting device (e.g., an LED) and a tactile feedback device (e.g., a vibration motor), etc. The above-mentioned display device includes but is not limited to a liquid crystal display, a light emitting diode, a display and a plasma display. In some optional embodiments, the display device can be a touch screen.

[0203] The embodiment of the present invention also provides a computer-readable storage medium. The method according to the embodiment of the present invention can be implemented in hardware, firmware, or can be implemented as a computer code that can be recorded in a storage medium, or can be implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and will be stored in a local storage medium through a network download, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state hard disk, etc.; further, the storage medium can also include a combination of the above types of memories. It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor, or hardware, the method shown in the above embodiment is implemented.

[0204] A part of the present invention may be applied as a computer program product, such as a computer program instruction, which, when executed by a computer, can call or provide the method and / or technical solution according to the present invention through the operation of the computer. Those skilled in the art should understand that the existence of the computer program instruction in a computer-readable medium includes, but is not limited to, a source file, an executable file, an installation package file, etc., and accordingly, the way in which the computer program instruction is executed by the computer includes, but is not limited to: the computer directly executes the instruction, or the computer compiles the instruction and then executes the corresponding compiled program, or the computer reads and executes the instruction, or the computer reads and installs the instruction and then executes the corresponding installed program. Here, the computer-readable medium may be any available computer-readable storage medium or communication medium accessible to the computer.

[0205] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A method for balancing battery cell capacity, characterized in that: The method comprises: Obtain charging data of each cell in the target battery during the charging process; Determining, according to the charging data corresponding to each of the battery cells, a charging voltage inflection point corresponding to each of the battery cells during the charging process; Calculating the current available capacity of each battery cell according to the charging voltage inflection point corresponding to each battery cell; Capacity balancing is performed on each of the battery cells according to the currently available capacity corresponding to each of the battery cells.

2. The method according to claim 1, characterized in that The charging data includes state of charge data, voltage data and current data, and determining the charging voltage inflection point corresponding to each of the battery cells during the charging process according to the charging data corresponding to each of the battery cells includes: Identifying the state of charge data; If the state of charge data is within a preset state of charge range, acquiring the voltage data and the current data of each battery cell during the charging process; The charging voltage inflection point corresponding to each of the battery cells during the charging process is determined according to each of the voltage data and each of the current data.

3. The method according to claim 2, characterized in that The step of determining the charging voltage inflection point corresponding to each of the battery cells during the charging process according to each of the voltage data and each of the current data includes: For each of the battery cells, generating a capacity increment curve corresponding to the battery cell according to the voltage data corresponding to the battery cell and the capacitance increment after integrating the current data, wherein the capacity increment curve is used to characterize the change in battery cell capacity corresponding to each unit voltage change of the battery cell; determining a minimum point in the capacity increment curve; The minimum value point is determined as the charging voltage inflection point corresponding to the battery cell during the charging process.

4. The method according to claim 1, characterized in that: The charging data includes charging end time and charging current data, and the current available capacity corresponding to each battery cell is calculated according to the charging voltage inflection point corresponding to each battery cell, including: Determine a target inflection point moment corresponding to each of the battery cells, the target inflection point moment including a moment when the battery cell is at the charging voltage inflection point; Obtaining a first available capacity of each of the battery cells corresponding to the target inflection point; The second available capacity corresponding to each of the battery cells is calculated by multiplying the current data by the time difference between the target inflection point moment corresponding to each of the battery cells and the lowest inflection point moment corresponding to the battery cell with the lowest voltage identified; The current available capacity corresponding to each of the battery cells is calculated by adding the first available capacity to the second available capacity.

5. The method according to claim 4, characterized in that The charging data includes voltage data; each of the battery cells includes a first battery cell for which the charging voltage inflection point is detected and a second battery cell for which the charging voltage inflection point is not detected, and determining the target inflection point time corresponding to each of the battery cells includes: Based on the voltage data corresponding to each of the battery cells, sorting the first battery cells and the second battery cells; According to the arrangement order of the first battery cells and the second battery cells, the target inflection point moments corresponding to the first battery cells are used to perform interpolation calculations on the second battery cells to obtain the target inflection point moments corresponding to the second battery cells, wherein the target inflection point moment of the first battery cell is the moment when the charging voltage inflection point is detected.

6. The method according to any one of claims 1 to 5, characterized in that: The step of balancing the capacities of the battery cells according to the current available capacities corresponding to the battery cells comprises: Calculating a first difference between the current available capacity corresponding to each of the battery cells and a minimum current available capacity; For the third battery cell, if the first difference is greater than the first preset difference threshold, a second difference between the first difference and the first preset difference threshold is calculated, and the third battery cell is controlled to release the capacity of the second difference, and the third battery cell is any one of the battery cells.

7. The method according to any one of claims 1 to 5, characterized in that: The step of balancing the capacities of the battery cells according to the current available capacities corresponding to the battery cells comprises: Calculate the average available capacity corresponding to the current available capacity corresponding to each of the battery cells; For the fourth battery cell, a third difference is calculated by subtracting the average available capacity from the current available capacity corresponding to the fourth battery cell; If the third difference is greater than the second preset difference threshold, a fourth difference between the third difference and the second preset difference threshold is calculated, and the fourth battery cell is controlled to discharge the capacity of the fourth difference to the energy storage component of the active balancing circuit; If the third difference is less than the third preset difference threshold, a fifth difference between the third preset difference threshold and the third difference is calculated, and the energy storage component of the active balancing circuit is controlled to charge the fourth battery cell with a capacity of the fifth difference, the fourth battery cell being any one of the battery cells, and the second preset difference threshold being greater than the third preset difference threshold.

8. A battery cell capacity balancing device, characterized in that: The device comprises: An acquisition module is used to acquire charging data of each cell in the target battery during the charging process; A determination module, used to determine a charging voltage inflection point corresponding to each of the battery cells during the charging process according to the charging data corresponding to each of the battery cells; A calculation module, used for calculating the current available capacity corresponding to each of the battery cells according to the charging voltage inflection point corresponding to each of the battery cells; The capacity balancing module is used to balance the capacity of each of the battery cells according to the current available capacity corresponding to each of the battery cells.

9. A computer device, characterized in that: include: A memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the battery cell capacity balancing method according to any one of claims 1 to 7 by executing the computer instructions.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a computer to execute the battery cell capacity balancing method according to any one of claims 1 to 7.

11. A computer program product, characterized in that The method comprises computer instructions, wherein the computer instructions are used to enable a computer to execute the battery cell capacity balancing method according to any one of claims 1 to 7.

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