Battery uniformity correction method

Abstract

The application provides a battery consistency correction method. The battery consistency correction method comprises the following steps: obtaining the bare cell internal resistance R1 and the battery monomer internal resistance R2 of each battery monomer under the same test condition; calculating the external circuit resistance R of each battery monomer according to the bare cell internal resistance R1 and the battery monomer internal resistance R2, wherein R=R2-R1; calculating the correction internal resistance r_j_corr of each battery monomer according to the external circuit resistance R; obtaining the monomer voltage of the battery monomer, and correcting the monomer voltage by using the correction internal resistance r_j_corr of the battery monomer to obtain the corrected monomer voltage. The battery consistency correction method can correct the unreasonable pressure difference in the battery module, eliminate the pressure difference, improve the maximum charge and discharge capacity of the battery module, the maximum output power, and the accuracy of the SOC capacity estimation.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more specifically, to a battery consistency correction method. Background Technology

[0002] A battery module is composed of many individual battery cells, which are connected to electrical connectors by welding or bolting. The electrical connectors connect these individual battery cells in series or parallel to form a battery module with a certain voltage and capacity level. Battery modules are usually equipped with a battery management system (BMS) to collect and monitor state information such as voltage, current and temperature of the battery module, and to estimate the state of charge (SOC) and state of health (SOH) of the battery.

[0003] The most important information for evaluating the State of Charge (SOC) and State of Health (SOH) of a battery module is the voltage of each individual battery cell within the module. The Battery Management System (BMS) can determine the consistency of the battery system based on the voltage differences between individual cells. The SOC of a battery module is determined by the cell with the lowest voltage. However, even if each individual cell is normal, they will still exhibit certain differences after being assembled into a battery module. Moreover, these differences will appear as regular ripples. This is because the BMS collects the voltage of individual cells by measuring the voltage between the electrical connectors at the positive and negative terminals of the cells. Since both individual cells and external circuits have internal resistance, and the internal resistance of individual cells is very low, typically in the mΩ range, a voltage drop occurs when current flows through the electrical connectors. This results in differences in the individual cell voltages collected by the BMS, causing significant voltage differences between cells that were originally in the same factory condition. This voltage difference increases exponentially with the increase of discharge current, making previously normal individual cells the weakest link in the battery module. This severely reduces the battery's state of charge and the power capability of the battery module at the end of discharge.

[0004] This technology discloses a method for assessing the consistency and safety status of power batteries. By acquiring a large amount of historical operating data from the vehicle under evaluation, the standard deviation and variance entropy consistency characteristics of the single-cell voltage for each charging data segment are calculated to obtain feature values. The number of charge-discharge cycles is also obtained. These feature values ​​are then used to construct a feature matrix, which is subjected to unsupervised training using a pre-defined algorithm to obtain a confusion matrix. A quantitative calculation model for the consistency and safety status of the power battery is then constructed based on the confusion matrix. By quantitatively assessing the consistency and safety status of the power battery, risk factors can be more intuitively identified from a large amount of historical operating data. This method can dynamically identify the confusion matrix of a vehicle after a period of operation, thus assessing the internal consistency of the battery.

[0005] However, due to the electrochemical characteristics of a battery cell, its internal resistance changes constantly with the cell's capacity and charging / discharging current. Therefore, directly collecting the cell's internal resistance and then calculating its current voltage based on the current is extremely inaccurate. Summary of the Invention

[0006] The main objective of this invention is to provide a battery consistency correction method that can correct unreasonable voltage differences within a battery module, thereby eliminating voltage differences, increasing the maximum charge / discharge capacity and maximum output power of the battery module, and improving the accuracy of SOC capacity estimation.

[0007] To achieve the above objectives, according to one aspect of the present invention, a battery consistency correction method is provided, characterized in that it includes:

[0008] Obtain the bare cell internal resistance R1 and the cell internal resistance R2 of each battery cell under the same test conditions;

[0009] Calculate the external circuit resistance R of each battery cell based on the bare cell internal resistance R1 and the battery cell internal resistance R2, where R = R2 - R1.

[0010] Calculate the corrected internal resistance r_j_corr of each battery cell based on the external circuit resistance R of each battery cell;

[0011] Obtain the individual cell voltage of the battery cell, retrieve the corrected internal resistance r_j_corr of the battery cell to correct the individual cell voltage, and obtain the corrected individual cell voltage.

[0012] Furthermore, the step of calculating the corrected internal resistance r_j_corr of each battery cell based on the external circuit resistance R of each battery cell includes:

[0013] Calculate the average single-cell voltage V_ave = (V_all - I * R_all) / j within a battery module, where V_all is the total voltage of the battery string, I is the current of the battery string, j is the number of single-cell batteries in the battery string, and R_all is the sum of the external circuit resistances of the battery string.

[0014] Calculate the pressure difference vector ΔVj set SET_B=[ΔV1,ΔV2,ΔV3…ΔVj], where ΔVj=Vj-V_ave;

[0015] Calculate the current of the battery string I = I_test / n, where I_test is the test current and n is the number of parallel battery cells in the battery module;

[0016] Calculate the set SET_C = SET_B / I for the corrected internal resistance r_j_corr, where the set member r_j_corr = (Vj - V_ave)*n / I_test.

[0017] Further, the step of obtaining the individual cell voltage of the battery cell, retrieving the corrected internal resistance r_j_corr of the battery cell to correct the individual cell voltage, and obtaining the corrected individual cell voltage includes:

[0018] The corrected single-cell voltage is obtained using the formula Vj_corr=Vj+r_j_corr*I_now / n, where Vj is the current voltage of the j-th cell in the same battery string, and I_now is the current actual current of the battery string.

[0019] Establish the corrected set of individual unit voltages Vj_corr: SET_A = [V1_corr, V2_corr, V3_corr, ... Vj_corr].

[0020] Furthermore, the step of calculating the external circuit resistance R of each battery cell based on its bare cell internal resistance R1 and battery cell internal resistance R2, wherein R = R2 - R1, further includes:

[0021] Adjust the test conditions to obtain the external circuit resistance of each battery cell calculated under various different test conditions;

[0022] The average value of the external circuit resistance of the same battery cell is taken to obtain the external circuit resistance R of that battery cell.

[0023] Furthermore, the same test conditions were used, including the same power, current, SOC, and temperature settings.

[0024] Furthermore, the internal resistance R1 of the bare cell and the internal resistance R2 of the battery cell are obtained through constant power or constant current charging or discharging.

[0025] Furthermore, during the calculation of the bare cell internal resistance R1 and the battery cell internal resistance R2 through constant current charging or discharging, the battery ratio used when measuring the bare cell internal resistance R1 and the battery cell internal resistance R2 is the ratio of the battery rated current.

[0026] Furthermore, the battery used has a current rating of 1C or 0.5C, where C is the battery's rated current.

[0027] Furthermore, the battery module includes N battery cells, with n cells in parallel and j cells in series, where N = n * j. The step of calculating the corrected internal resistance r_j_corr of each battery cell based on its external circuit resistance R further includes:

[0028] The corrected internal resistance of each individual cell in each battery string within the battery module is calculated sequentially and stored.

[0029] Furthermore, the battery consistency correction method is implemented by the battery management system.

[0030] The battery consistency correction method using the technical solution of this invention includes: obtaining the bare cell internal resistance R1 and the battery cell internal resistance R2 of each battery cell under the same test conditions; calculating the external circuit resistance R of each battery cell based on the bare cell internal resistance R1 and the battery cell internal resistance R2, where R = R2 - R1; calculating the corrected internal resistance r_j_corr of each battery cell based on the external circuit resistance R; obtaining the cell voltage of the battery cell, and correcting the cell voltage by retrieving the corrected internal resistance r_j_corr of the battery cell to obtain the corrected cell voltage. This battery consistency correction method obtains the resistance of all external circuits within the battery module by collecting the bare cell internal resistance and the internal resistance of the battery cell at a specific moment. Since the external circuits are all metal components, their internal resistance is constant under normal circumstances. Therefore, the corrected internal resistance of the battery cell can be determined using the external circuit resistance. Then, the corrected internal resistance is used to correct unreasonable voltage difference conditions within the battery module, so that all battery cells in the battery module can reach the upper and lower limits almost simultaneously. This corrects unreasonable voltage difference conditions within the battery module, eliminates voltage difference, improves the maximum charge and discharge capacity and maximum output power of the battery module, and improves the accuracy of SOC capacity estimation. Attached Figure Description

[0031] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0032] Figure 1 A schematic diagram of a battery consistency correction method according to an embodiment of the present invention is shown; and

[0033] Figure 2 A flowchart of a battery consistency correction method according to an embodiment of the present invention is shown. Detailed Implementation

[0034] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0035] See also Figure 1 and Figure 2As shown, the present invention provides a battery consistency correction method, comprising: obtaining the bare cell internal resistance R1 and the battery cell internal resistance R2 of each battery cell under the same test conditions; calculating the external circuit resistance R of each battery cell based on the bare cell internal resistance R1 and the battery cell internal resistance R2, wherein R = R2 - R1; calculating the corrected internal resistance r_j_corr of each battery cell based on the external circuit resistance R; obtaining the cell voltage of the battery cell, and correcting the cell voltage by retrieving the corrected internal resistance r_j_corr of the battery cell to obtain the corrected cell voltage.

[0036] Due to the electrochemical characteristics of a battery cell, its internal resistance changes constantly with the cell's capacity and charging / discharging current. Therefore, directly collecting the cell's internal resistance and calculating its current voltage based on the current is extremely inaccurate.

[0037] The battery consistency correction method of the present invention obtains the resistance of all external circuits in the battery module by collecting the bare cell internal resistance and the internal resistance of the battery cell at a specific moment. Since the external circuits are all metal parts, their internal resistance is constant under normal circumstances. Therefore, the corrected internal resistance of the battery cell can be determined by using the external circuit resistance. Then, the corrected internal resistance is used to correct unreasonable voltage difference in the battery module, so that all battery cells in the battery module can reach the upper and lower limits almost simultaneously. This corrects unreasonable voltage difference in the battery module, eliminates voltage difference, improves the maximum charge and discharge capacity and maximum output power of the battery module, and improves the accuracy of SOC capacity estimation.

[0038] The method provided in this embodiment is a battery consistency correction method for battery modules. The battery module can be a single-cell string battery module or a multi-parallel-connected cell string battery module. A single-cell string battery module means that the battery module includes only one cell string, while a multi-parallel-connected cell string battery module means that the battery module includes multiple cell strings connected in parallel. The above-described battery consistency correction method is applicable to the battery consistency correction of any type of battery module.

[0039] In this embodiment, a battery cell includes a bare cell and an external circuit connected to the bare cell. The internal resistance R2 of the battery cell is the sum of the internal resistance R1 of the bare cell and the resistance R of the external circuit. Therefore, after measuring the internal resistance R1 of the bare cell and the internal resistance R2 of the battery cell, the difference between the two is the external circuit resistance R corresponding to the bare cell.

[0040] In one embodiment, the same test conditions are the same set power, current, SOC, and temperature.

[0041] In calculating the corrected internal resistance, it is necessary to first determine the bare cell internal resistance and the battery cell internal resistance at a specific moment under the same set power, current, SOC, and temperature conditions. Then, the external circuit resistance corresponding to each bare cell is calculated using the bare cell internal resistance and the battery cell internal resistance. Since the external circuit resistance is basically constant, the external circuit resistance calculated at any moment is essentially consistent. Based on this, the corrected internal resistance can be calculated under the initial conditions of the battery module at the factory. Since the bare cells in the battery module are in their initial state at this time, it can be assumed that the bare cell internal resistance of the battery cell obtained by measuring and calculating it individually under this condition is consistent with the actual bare cell internal resistance of the battery cell in the battery module. Therefore, the external circuit resistance calculated in this way is also accurate.

[0042] In one embodiment, the internal resistance R1 of the bare cell and the internal resistance R2 of the battery cell are obtained by charging or discharging the battery cell and battery module with constant power or constant current.

[0043] In this embodiment, the steps of obtaining the bare cell internal resistance R1 and battery cell internal resistance R2 of each battery cell under the same test conditions specifically include: measuring the bare cell internal resistance R1 and battery cell internal resistance R2 of the battery cell, and performing constant power or constant current charging or discharging on the battery cell and battery module respectively. Due to the influence of the electrochemical characteristics within the battery cell, its internal resistance will increase with the increase of capacity and current. The bare cell internal resistance R1 and battery cell internal resistance R2 of the battery cell under a specific state can be obtained by constant power or constant current charging and discharging.

[0044] After measuring the bare cell internal resistance R1 and the battery cell internal resistance R2 of the individual battery cells, it is also necessary to collect the test current I_test, the total voltage V_all of each battery string, the number of individual battery cells N, the number of parallel battery cells, and the number of strings j of each battery string of the battery module; in addition, it is also necessary to collect the voltage set SET_A = [V1, V2, V3...Vj] of each bare cell in order to provide data support for the subsequent calculation of the corrected internal resistance.

[0045] In one embodiment, the step of calculating the external circuit resistance R of a battery cell based on the bare cell internal resistance R1 and the battery cell internal resistance R2, wherein R = R2 - R1, further includes: adjusting the test conditions to obtain the external circuit resistance of each battery cell calculated under various different test conditions; and taking the average value of the external circuit resistance of the same battery cell to obtain the external circuit resistance R of the battery cell.

[0046] To improve the accuracy of the calculated external circuit resistance R, this invention allows for the acquisition of multiple sets of bare cell internal resistance R1 and battery cell internal resistance R2 under identical conditions by setting multiple sets of power, current, SOC, and temperature. Theoretically, the external circuit resistance corresponding to a bare cell is constant. However, due to factors such as the battery's environment, the external circuit resistance obtained under different conditions may vary. Therefore, multiple sets of external circuit resistances under different conditions can be obtained, and then the average value of these resistances is calculated to obtain a more accurate external circuit resistance R.

[0047] Under the same charging and discharging conditions, the bare cell internal resistance R1 of a single battery cell measured individually is the same as the bare cell internal resistance calculated within the battery module. Therefore, the external circuit resistance R of the external circuit in the battery module after removing the bare cells can be obtained in this way.

[0048] In one embodiment, the step of calculating the corrected internal resistance r_j_corr of each battery cell based on the external circuit resistance R of each battery cell includes: calculating the average cell voltage V_ave = (V_all - I * R_all) / j of a battery string within the battery module, where V_all is the total voltage of the battery string, I is the current of the battery string, j is the number of battery cells in the battery string, and R_all is the sum of the external circuit resistances of the battery string; calculating the voltage difference vector ΔVj set SET_B = [ΔV1, ΔV2, ΔV3…ΔVj], where ΔVj = Vj - V_ave; calculating the current of the battery string I = I_test / n, where I_test is the test current and n is the number of parallel battery cells in the battery module; and calculating the corrected internal resistance r_j_corr set SET_C = SET_B / I, where the set member r_j_corr = (Vj - V_ave) * n / I_test.

[0049] In this embodiment, the calculation process for the corrected internal resistance r_j_corr of each battery cell based on the external circuit resistance R of each battery cell is as follows:

[0050] Calculate the average cell voltage V_ave = (V_all - I*R_all) / j. Remove the voltage drop generated by the external circuit resistance R from the entire battery string to obtain the total voltage of all cells in a battery string. Then, remove the total number of cells j in the battery string to obtain the average cell voltage V_ave of the battery string.

[0051] Calculate the pressure difference vector ΔVj set SET_B=[ΔV1,ΔV2,ΔV3...ΔVj], where ΔVj=Vj-V_ave.

[0052] Calculate the current of the battery string I = I_test / n. Since n battery strings are connected in parallel, and each battery string has the same number of strings, the battery cells in each battery string are in the same position, and the environment during operation is the same, it can be assumed that the current of each battery string is the same. Therefore, the current of each battery string should be the ratio of the total current to the number of parallel battery cells n in the battery module.

[0053] The set SET_C = SET_B / j is used to calculate the corrected internal resistance r_j_corr, where the set member r_j_corr = (Vj - V_ave)*n / I_test. The corrected internal resistance r_j_corr varies at each individual cell, and its magnitude is determined by the location of the voltage acquisition point of the BMS, the thickness and material of the electrical connector. The corrected internal resistance r_j_corr is the external circuit resistance (excluding the internal resistance of the battery cell) of the external circuit that exists between the BMS acquisition points.

[0054] In one embodiment, the steps of obtaining the individual cell voltage of a battery cell, retrieving the corrected internal resistance r_j_corr of the battery cell to correct the individual cell voltage, and obtaining the corrected individual cell voltage include:

[0055] The corrected individual cell voltage is obtained using the formula Vj_corr=Vj+r_j_corr*I_now / n, where Vj is the current voltage of the j-th cell in the same battery string, and I_now is the current actual current of the battery string; a set of corrected individual cell voltages Vj_corr is established: SET_A=[V1_corr,V2_corr,V3_corr…Vj_corr].

[0056] The corrected cell voltage Vj_corr = Vj + r_j_corr * I_now / n. After the BMS calculates and stores the corrected internal resistance set r_j_corr, it will call the corrected internal resistance when collecting the cell voltage during each charge and discharge process to calculate the accurate value of the cell voltage.

[0057] This invention obtains the external circuit resistance of all external circuits within the battery module by collecting the internal resistance of individual battery cells and the internal resistance of the battery module at a specific moment. Since the external circuits are all metal components, their external circuit resistance remains constant under normal circumstances. Then, the total voltage of a battery string is subtracted from the voltage shared by the external circuit of that battery string to obtain the total voltage of all individual battery cells in that battery string. When the battery is first manufactured, it can be assumed that the voltage of each individual battery cell is the same. Therefore, the voltage of each individual battery cell can be obtained by dividing the total voltage by the total number of individual battery cells. Then, the voltage difference vector value is obtained by comparing the individual battery cell voltage collected by the BMS with the calculated individual battery cell voltage. Dividing this value by the current allows for the calculation of the corrected internal resistance of the external circuit of each individual battery cell. This corrects the individual cell voltage collected by the BMS in subsequent operations.

[0058] In one embodiment, during the calculation of the bare cell internal resistance R1 and the battery cell internal resistance R2 through constant current charging or discharging, the battery ratio used when measuring the bare cell internal resistance R1 and the battery cell internal resistance R2 is the ratio of the battery rated current.

[0059] In one embodiment, the battery rate used is 1C or 0.5C, where C is the battery's rated current.

[0060] In one embodiment, the battery module includes N battery cells, with n cells in parallel and j cells in series, where N = n * j. The step of calculating the corrected internal resistance r_j_corr of each battery cell based on its external circuit resistance R further includes:

[0061] The corrected internal resistance of each individual cell in each battery string within the battery module is calculated sequentially and stored.

[0062] In one embodiment, the battery consistency correction method is implemented by the battery management system (BMS).

[0063] The embodiments of the present invention have the following advantages:

[0064] 1) It eliminates the voltage difference caused by the battery module grouping and increases the SOC of the battery module. Since the SOC of the battery module is determined by the individual battery cells, when the BMS detects that the SOC of the individual battery cells has reached the upper or lower limit, it will control the battery module to stop charging and discharging to protect the battery. However, the embodiment of the present invention makes the voltage of all individual battery cells the same in the initial state, which greatly eliminates unreasonable design voltage differences, so that all individual battery cells in the battery module can reach the upper and lower limits almost simultaneously, thereby allowing each individual battery cell to be fully charged and discharged.

[0065] 2) It avoids overcharging and over-discharging of individual battery cells. Due to the design, individual battery cells have a large voltage difference in the initial state. This causes some individual battery cells in the battery module to have voltage sampling values ​​that do not reach the cutoff charge / discharge voltage during charging and discharging, but the actual values ​​have reached the cutoff charge / discharge voltage. This results in overcharging or over-discharging of individual battery cells, affecting the overall lifespan of the battery module. The embodiments of the present invention can avoid this situation.

[0066] 3) If there is a large voltage difference between the individual battery cells in the battery module, and if the battery module needs to provide a large current discharge at the end of the discharge period (such as vehicle acceleration), the voltage difference between the individual battery cells will rise rapidly, causing some individual battery cells to immediately reach the discharge cutoff voltage. This greatly weakens the power output capability of the battery module at the end of the discharge period. The embodiments of the present invention can eliminate this effect and can greatly optimize the power output capability of the battery module at the end of the discharge period.

[0067] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0068] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application 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 this application described herein can be implemented in sequences other than those illustrated or described herein.

[0069] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A battery consistency correction method, characterized in that, include: Obtain the bare cell internal resistance R1 and the cell internal resistance R2 of each battery cell under the same test conditions; Calculate the external circuit resistance R of each battery cell based on the bare cell internal resistance R1 and the battery cell internal resistance R2, where R = R2 - R1. Calculate the corrected internal resistance r_j_corr of each battery cell based on the external circuit resistance R of each battery cell; Obtain the cell voltage of the bare cell, retrieve the corrected internal resistance r_j_corr of the cell to correct the cell voltage, and obtain the corrected cell voltage. The step of calculating the corrected internal resistance r_j_corr of each battery cell based on the external circuit resistance R of each battery cell includes: Calculate the average single-cell voltage V_ave = (V_all - I*R_all) / j in a battery string within the battery module, where V_all is the total voltage of the battery string, I is the current of the battery string, j is the number of single-cell batteries in the battery string, and R_all is the sum of the external circuit resistances of the battery string. Calculate the pressure difference vector ΔVj set SET_B=[ΔV1, ΔV2, ΔV3…ΔVj], where ΔVj=Vj-V_ave; where Vj is the current voltage of the bare cell of the j-th battery in the same battery string. Calculate the current of the battery string I = I_test / n, where I_test is the test current and n is the number of parallel battery cells in the battery module; Calculate the set SET_C=SET_B / I for the corrected internal resistance r_j_corr, where the set member r_j_corr = (Vj-V_ave)*n / I_test.

2. The battery consistency correction method according to claim 1, characterized in that, The steps of obtaining the individual cell voltage of a battery cell, and correcting the individual cell voltage by retrieving the corrected internal resistance r_j_corr of the battery cell to obtain the corrected individual cell voltage include: The corrected cell voltage is obtained using the formula Vj_corr = Vj + r_j_corr * I_now / n, where I_now is the current current of the actual battery string. Establish the corrected set of individual unit voltages Vj_corr: SET_A = [V1_corr, V2_corr, V3_corr…Vj_corr].

3. The battery consistency correction method according to claim 1, characterized in that, The step of calculating the external circuit resistance R of a battery cell based on the bare cell internal resistance R1 and the battery cell internal resistance R2, wherein R = R2 - R1, further includes: Adjust the test conditions to obtain the external circuit resistance of each battery cell calculated under various different test conditions; The average value of the external circuit resistance of the same battery cell is taken to obtain the external circuit resistance R of that battery cell.

4. The battery consistency correction method according to claim 1, characterized in that, The same test conditions were applied, including the same power, current, SOC, and temperature settings.

5. The battery consistency correction method according to claim 1, characterized in that, The internal resistance R1 of the bare cell and the internal resistance R2 of the battery cell are obtained by constant power or constant current charging or discharging.

6. The battery consistency correction method according to claim 5, characterized in that, When calculating the internal resistance R1 of the bare cell and the internal resistance R2 of the battery cell through constant current charging or discharging, the battery ratio used when measuring the internal resistance R1 of the bare cell and the internal resistance R2 of the battery cell is the ratio of the rated current of the battery.

7. The battery consistency correction method according to claim 6, characterized in that, The battery used has a current rating of 1C or 0.5C, where C is the rated current of the battery.

8. The battery consistency correction method according to claim 1, characterized in that, The battery module comprises N battery cells, with n cells in parallel and j cells in series, where N = n * j. The step of calculating the corrected internal resistance r_j_corr of each battery cell based on its external circuit resistance R further includes: The corrected internal resistance of each individual cell in each battery string within the battery module is calculated sequentially and stored.

9. The battery consistency correction method according to claim 1, characterized in that, The battery consistency correction method is implemented by the battery management system.

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