Voltage compensation method and device of battery management system, vehicle and storage medium

Abstract

The application relates to a voltage compensation method and device of a battery management system, a vehicle and a storage medium, wherein the method comprises the following steps: detecting whether a preset compensation condition of the battery management system is met; in the case that it is detected that the preset compensation condition of the battery management system is met, performing a compensation task on a battery pack to obtain a pressure difference generated by an actual copper bar of the battery pack; and calculating a copper bar internal resistance of the battery pack according to the pressure difference generated by the actual copper bar, so as to generate a voltage compensation value according to the copper bar internal resistance. Thus, the problem that, in the related art, due to the fact that the internal resistance of the copper bar is ignored, when the battery pack is subjected to large-current charging and discharging, the internal resistance can cause obvious pressure difference, the single-cell voltage acquisition data is inaccurate, and the estimation of the battery state by the BMS system is wrong and the like is solved.

Description

Technical Field

[0001] This application relates to the field of power battery technology, and in particular to a voltage compensation method, device, vehicle, and storage medium for a battery management system. Background Technology

[0002] Currently, in electric vehicles, the power battery, as a crucial energy source, directly affects many key performance aspects of the entire vehicle. The BMS (Battery Management System) is a vital component connecting the power battery and the vehicle. Its main functions include real-time monitoring of battery physical parameters, battery state estimation, online diagnostics and early warning, charge / discharge and pre-charge control, equalization management, and thermal management. Most of these functions require the collection of status information such as individual cell voltage and temperature of the battery pack. Therefore, the accuracy of the individual cell voltage data is particularly critical.

[0003] In related technologies, copper busbars are used to connect the modules inside the battery pack. In order to reduce the number of acquisition channels, the connecting copper busbar between the modules inside the battery pack and the voltage of an adjacent single cell are regarded as a single cell and are used together as a voltage acquisition point for signal sampling.

[0004] However, in related technologies, the internal resistance of the copper busbar is ignored. When the battery pack is charged and discharged at high current, even a small internal resistance can cause a large voltage difference, which leads to deviations in the data collected by individual cell voltages. This results in errors in the BMS system's estimation of the battery state, which urgently needs to be improved. Summary of the Invention

[0005] This application provides a voltage compensation method, device, vehicle, and storage medium for a battery management system to solve the problems in related technologies, such as the significant voltage difference caused by the internal resistance of the copper busbar when the battery pack is charged and discharged at high current, which leads to inaccurate data acquisition of individual cell voltages and errors in the BMS system's estimation of battery status, due to the neglect of the internal resistance of the copper busbar.

[0006] The first aspect of this application provides a voltage compensation method for a battery management system, comprising the following steps: detecting whether the battery management system meets a preset compensation condition; if the battery management system meets the preset compensation condition, performing a compensation task on the battery pack to obtain the voltage difference generated by the actual copper busbar of the battery pack; calculating the internal resistance of the copper busbar of the battery pack based on the voltage difference generated by the actual copper busbar, so as to generate a voltage compensation value based on the internal resistance of the copper busbar.

[0007] Through the above-mentioned technical means, the embodiments of this application can perform compensation tasks on the battery pack to collect the actual voltage difference of the copper busbar when it is determined that the battery management system meets the compensation conditions. Based on the actual voltage difference of the copper busbar, the internal resistance of the copper busbar is calculated, and a voltage compensation value associated with the real-time current is generated. This can minimize the impact of the bridging copper busbar on the voltage of individual cells, enabling the battery management system to obtain the true voltage of individual cells after eliminating the influence of the copper busbar voltage division. This effectively improves the accuracy of battery state estimation such as state of charge and state of health, and ensures the overall performance and safety of electric vehicles.

[0008] Optionally, in one embodiment of this application, the preset compensation conditions are: the battery management system is in an offline electrical inspection state; the charging current or discharging current of the battery pack meets the preset high current condition; the current sensor of the battery pack is fault-free; the battery management system has not performed overvoltage compensation; and the copper busbar resistance and cell internal resistance of the battery pack are both within a preset reasonable range.

[0009] Through the above-mentioned technical means, the embodiments of this application can ensure that the voltage compensation operation is performed under appropriate operating conditions by setting multiple judgment conditions, including operating conditions, current magnitude, sensor fault status, compensation execution records, and battery internal resistance parameters. This avoids misjudgment or incorrect compensation caused by performing compensation operations under unsuitable operating conditions, ensures the effectiveness and reliability of detection data in the voltage compensation task, and improves the reliability and applicability of the compensation strategy.

[0010] Optionally, in one embodiment of this application, performing a compensation task on the battery pack to obtain the actual voltage difference generated by the copper busbars of the battery pack includes: before performing the compensation task on the battery pack, acquiring at least one set of static voltage values ​​of the battery pack to determine a first voltage value of the battery pack based on the at least one set of static voltage values; during the performance of the compensation task on the battery pack, acquiring at least one set of discharged voltage values ​​of the battery pack to determine a second voltage value of the battery pack based on the at least one set of discharged voltage values; and calculating the actual voltage difference generated by the copper busbars of the battery pack based on the first voltage value and the second voltage value.

[0011] Through the above-mentioned technical means, the embodiments of this application can effectively separate the true voltage difference caused by the internal resistance of the copper busbar by collecting voltage values ​​in the static state and the discharge state before and after the compensation task is executed. This can eliminate the influence of irrelevant factors such as voltage fluctuations of the battery cell itself and environmental interference, providing a reliable data basis for the subsequent accurate calculation of the internal resistance of the copper busbar, and improving the accuracy and repeatability of the voltage difference measurement.

[0012] Optionally, in one embodiment of this application, the step of calculating the internal resistance of the copper busbar of the battery pack based on the voltage difference generated by the actual copper busbar includes: calculating the internal resistance of the copper busbar based on the voltage difference generated by the actual copper busbar and the current value of the battery pack when performing the compensation task; or, determining the corresponding resistance of the cell voltage affected by the copper busbar based on the voltage difference generated by the actual copper busbar, and calculating the internal resistance of the copper busbar based on the corresponding resistance and the average value of the cell internal resistance of the battery pack.

[0013] Through the above-mentioned technical means, the embodiments of this application can calculate the internal resistance of the copper busbar by the direct relationship between the voltage difference and current generated by the actual copper busbar, or by analyzing the difference between the resistance of the corresponding single cell voltage affected by the copper busbar and the internal resistance of the cell. Thus, the execution can be selected according to the actual data type, so as to adapt to different hardware acquisition conditions and different battery pack test scenarios, improve versatility and fault tolerance, and ensure that the internal resistance parameters of the copper busbar can be accurately obtained under different calculation methods.

[0014] Optionally, in one embodiment of this application, generating a voltage compensation value based on the internal resistance of the copper busbar includes: obtaining the current charging / discharging current of the battery pack; and calculating the voltage compensation value based on the internal resistance of the copper busbar and the current charging / discharging current.

[0015] Through the above-mentioned technical means, the embodiments of this application can dynamically generate a voltage compensation value that matches the real-time operating conditions by using the identified copper busbar internal resistance and the real-time collected current charging and discharging current during actual vehicle operation. This ensures that the influence of the copper busbar internal resistance on the single cell voltage acquisition can be effectively eliminated under different load conditions, so that the battery state estimation can continuously obtain real single cell voltage information, thereby improving the voltage acquisition accuracy and battery state estimation reliability of the battery management system under various operating conditions.

[0016] A second aspect of this application provides a voltage compensation device for a battery management system, comprising: a detection module for detecting whether the battery management system meets a preset compensation condition; an acquisition module for performing a compensation task on a battery pack when the battery management system is detected to meet the preset compensation condition, thereby obtaining the actual voltage difference generated by the copper busbars of the battery pack; and a compensation module for calculating the internal resistance of the copper busbars of the battery pack based on the actual voltage difference generated by the copper busbars, thereby generating a voltage compensation value based on the internal resistance of the copper busbars.

[0017] Through the above-mentioned technical means, the embodiments of this application can perform compensation tasks on the battery pack to collect the actual voltage difference of the copper busbar when it is determined that the battery management system meets the compensation conditions. Based on the actual voltage difference of the copper busbar, the internal resistance of the copper busbar is calculated, and a voltage compensation value associated with the real-time current is generated. This can minimize the impact of the bridging copper busbar on the voltage of individual cells, enabling the battery management system to obtain the true voltage of individual cells after eliminating the influence of the copper busbar voltage division. This effectively improves the accuracy of battery state estimation such as state of charge and state of health, and ensures the overall performance and safety of electric vehicles.

[0018] Optionally, in one embodiment of this application, the preset compensation conditions are: the battery management system is in an offline electrical inspection state; the charging current or discharging current of the battery pack meets the preset high current condition; the current sensor of the battery pack is fault-free; the battery management system has not performed overvoltage compensation; and the copper busbar resistance and cell internal resistance of the battery pack are both within a preset reasonable range.

[0019] Through the above-mentioned technical means, the embodiments of this application can ensure that the voltage compensation operation is performed under appropriate operating conditions by setting multiple judgment conditions, including operating conditions, current magnitude, sensor fault status, compensation execution records, and battery internal resistance parameters. This avoids misjudgment or incorrect compensation caused by performing compensation operations under unsuitable operating conditions, ensures the effectiveness and reliability of detection data in the voltage compensation task, and improves the reliability and applicability of the compensation strategy.

[0020] Optionally, in one embodiment of this application, the acquisition module includes: a first determining unit, configured to acquire at least one set of static voltage values ​​of the battery pack before performing the compensation task on the battery pack, so as to determine a first voltage value of the battery pack based on the at least one set of static voltage values; a second determining unit, configured to acquire at least one set of discharged voltage values ​​of the battery pack during the process of performing the compensation task on the battery pack, so as to determine a second voltage value of the battery pack based on the at least one set of discharged voltage values; and a first calculating unit, configured to calculate the actual voltage difference generated by the copper busbar of the battery pack based on the first voltage value and the second voltage value.

[0021] Through the above-mentioned technical means, the embodiments of this application can effectively separate the true voltage difference caused by the internal resistance of the copper busbar by collecting voltage values ​​in the static state and the discharge state before and after the compensation task is executed. This can eliminate the influence of irrelevant factors such as voltage fluctuations of the battery cell itself and environmental interference, providing a reliable data basis for the subsequent accurate calculation of the internal resistance of the copper busbar, and improving the accuracy and repeatability of the voltage difference measurement.

[0022] Optionally, in one embodiment of this application, the compensation module includes: a second calculation unit, used to calculate the internal resistance of the copper busbar based on the voltage difference generated by the actual copper busbar and the current value when the battery pack performs the compensation task; and a third calculation unit, used to determine the corresponding resistance of the cell voltage affected by the copper busbar according to the voltage difference generated by the actual copper busbar, and to calculate the internal resistance of the copper busbar based on the corresponding resistance and the average value of the cell internal resistance of the battery pack.

[0023] Through the above-mentioned technical means, the embodiments of this application can calculate the internal resistance of the copper busbar by the direct relationship between the voltage difference and current generated by the actual copper busbar, or by analyzing the difference between the resistance of the corresponding single cell voltage affected by the copper busbar and the internal resistance of the cell. Thus, the execution can be selected according to the actual data type, so as to adapt to different hardware acquisition conditions and different battery pack test scenarios, improve versatility and fault tolerance, and ensure that the internal resistance parameters of the copper busbar can be accurately obtained under different calculation methods.

[0024] Optionally, in one embodiment of this application, the compensation module includes: a current acquisition unit for acquiring the current charging / discharging current of the battery pack; and a fourth calculation unit for calculating the voltage compensation value based on the internal resistance of the copper busbar and the current charging / discharging current.

[0025] Through the above-mentioned technical means, the embodiments of this application can dynamically generate a voltage compensation value that matches the real-time operating conditions by using the identified copper busbar internal resistance and the real-time collected current charging and discharging current during actual vehicle operation. This ensures that the influence of the copper busbar internal resistance on the single cell voltage acquisition can be effectively eliminated under different load conditions, so that the battery state estimation can continuously obtain real single cell voltage information, thereby improving the voltage acquisition accuracy and battery state estimation reliability of the battery management system under various operating conditions.

[0026] A third aspect of this application provides a vehicle including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the voltage compensation method of the battery management system as described in the above embodiments.

[0027] A fourth aspect of this application provides a non-volatile computer-readable storage medium storing a computer program that, when executed by a processor, implements the voltage compensation method of the battery management system described above.

[0028] A fifth aspect of this application provides a computer program product that stores a computer program that, when executed by a processor, implements the voltage compensation method of the battery management system described above.

[0029] This application embodiment can perform a compensation task on the battery pack to collect the actual voltage difference of the copper busbars when the battery management system meets the compensation conditions. Based on the actual voltage difference, the internal resistance of the copper busbars is calculated, and a voltage compensation value associated with the real-time current is generated. This minimizes the impact of the bridging copper busbars on the individual cell voltage, allowing the battery management system to obtain the true individual cell voltage after eliminating the voltage drop effect of the copper busbars. This effectively improves the accuracy of battery state estimation, such as state of charge and state of health, ensuring the overall performance and safety of the electric vehicle. Therefore, it solves the problem in related technologies where the internal resistance of the copper busbars is ignored, leading to a significant voltage difference during high-current charging and discharging of the battery pack, resulting in inaccurate individual cell voltage data and errors in the BMS system's estimation of the battery state.

[0030] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0031] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a schematic diagram showing the connection between modules within a battery pack via copper busbars in related technologies. Figure 2 This is a schematic diagram illustrating the impact of the internal resistance of the copper busbar on the acquisition of individual cell voltage in related technologies. Figure 3 This is a flowchart of a voltage compensation method for a battery management system according to an embodiment of this application; Figure 4 This is a schematic diagram illustrating the pressure difference generated by the actual copper busbars of a battery pack, according to an embodiment of this application. Figure 5 This is a schematic diagram of the structure of a voltage compensation device for a battery management system according to an embodiment of this application; Figure 6 This is a structural schematic diagram of a vehicle provided according to an embodiment of this application.

[0032] Figure label: 10-Voltage compensation device for battery management system; 100-Detection module, 200-Acquisition module, 300-Compensation module; 601-Memory, 602-Processor, 603-Communication interface. Detailed Implementation

[0033] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0034] The following description, with reference to the accompanying drawings, outlines a voltage compensation method, apparatus, vehicle, and storage medium for a battery management system according to embodiments of this application. Addressing the issues raised in the background section regarding related technologies where the internal resistance of the copper busbars is ignored, significant voltage differences arise during high-current charging and discharging of the battery pack. This leads to inaccurate individual cell voltage data acquisition and consequently, errors in the BMS system's estimation of battery status. This application provides a voltage compensation method for a battery management system. In this method, when the battery management system meets compensation conditions, a compensation task is performed on the battery pack to acquire the actual voltage difference of the copper busbars. Based on this actual voltage difference, the internal resistance of the copper busbars is calculated, generating a voltage compensation value associated with the real-time current. This minimizes the impact of the bridging copper busbars on individual cell voltages, enabling the battery management system to obtain the true individual cell voltages after eliminating the voltage drop effect of the copper busbars. This effectively improves the accuracy of battery status estimation, including state of charge and state of health, ensuring the overall performance and safety of the electric vehicle. This solves the problem in related technologies where the internal resistance of the copper busbar is ignored, causing a significant voltage difference when the battery pack is charged and discharged at high current. This leads to inaccurate data acquisition of individual cell voltages, which in turn causes errors in the BMS system's estimation of battery status.

[0035] Within the battery pack, modules are connected via copper busbars. The controller's acquisition chip, AFE, collects individual cell voltage data within the modules. If an AFE collects a single cell voltage that spans two modules, the copper busbar connecting the modules may be collected together with the individual cell voltage as a single cell voltage, as follows: Figure 1 As shown, the controller's P2-AFE collects the individual voltages of both module 1 and module 2. The negative acquisition line of cell 22, V22, and the positive acquisition line of V21 are collinear. V22 is in module 2, and V21 is in module 1. The copper busbar between module 2 and module 1 will be collected together with V22.

[0036] When there is a discharge current in the battery pack, the internal resistance of the copper busbar will create a reverse voltage, causing the actual sampled Cell22 voltage to be lower than the true V22 voltage. When there is a charging current in the battery pack, the internal resistance of the copper busbar will create a positive voltage, causing the actual sampled Cell22 voltage to be higher than the true V22 voltage. Figure 2 As shown.

[0037] Specifically, Figure 3This is a schematic flowchart of a voltage compensation method for a battery management system provided in an embodiment of this application.

[0038] like Figure 3 As shown, the voltage compensation method of this battery management system includes the following steps: In step S301, it is detected whether the battery management system meets the preset compensation conditions.

[0039] It is understood that the preset compensation conditions in the embodiments of this application can be used to determine whether the current battery pack operating conditions, hardware status, operation records, etc. meet the requirements of the start voltage compensation process. It is a preliminary judgment basis for carrying out subsequent compensation operations. It can be comprehensively limited from multiple dimensions such as operating conditions, current, equipment status, historical operations, and hardware parameters. The preset compensation conditions can be set by those skilled in the art according to the actual situation, and no specific restrictions are made here.

[0040] In actual implementation, the embodiments of this application can monitor various parameters in real time through the built-in detection module of the BMS system, including system operating status, current magnitude, sensor status, historical compensation records and resistance parameters, and verify them one by one according to the preset compensation conditions to complete the full-dimensional screening.

[0041] For example, in this embodiment of the application, the system can detect whether the BMS system is in the offline electrical test condition based on preset compensation conditions, and then verify whether the current charging and discharging current exceeds the set threshold (e.g., greater than 825A). At the same time, the system can query the local storage log to confirm that the battery pack has not performed overvoltage compensation, and verify whether the copper busbar resistance and the cell internal resistance are within a reasonable range (e.g., the cell internal resistance is between 80% and 120% of the typical value at room temperature, and the copper busbar resistance is within ±30% of the theoretically calculated value).

[0042] The embodiments of this application can confirm that the battery management system meets the preset compensation conditions, indicating that the current battery pack operating conditions, hardware status, operation records, etc. meet the requirements for starting voltage compensation. This effectively avoids the risks of introducing erroneous data when the sensor fails, causing the internal resistance value to be incorrectly refreshed after repeated execution, and performing invalid identification when the battery cell or copper busbar is abnormal. This provides a reliable data source and execution guarantee for subsequent differential pressure calculation and internal resistance identification.

[0043] In step S302, if the battery management system is found to meet the preset compensation conditions, a compensation task is performed on the battery pack to obtain the actual pressure difference generated by the copper busbars of the battery pack.

[0044] It is understood that the compensation task in this application embodiment can be understood as a voltage acquisition process designed to measure the voltage difference generated by the actual copper busbar. The voltage difference generated by the actual copper busbar can be understood as the voltage drop across the copper busbar when current flows due to the existence of the internal resistance of the copper busbar. This causes part of the voltage to be superimposed on the voltage acquisition channel containing the copper busbar, resulting in an overestimation of the acquired value and an error.

[0045] In actual implementation, this embodiment of the application can control the battery pack to perform a brief discharge operation when the battery management system is detected to meet preset compensation conditions. Simultaneously, it collects voltage data before and after the discharge and obtains the voltage difference generated by the copper busbar through comparative analysis. Specifically, the system of this embodiment uses the recorded voltage value of the battery pack in a static state as a reference to control the battery pack to perform a short-term high-current discharge, and records the voltage value after discharge. The actual voltage difference generated by the copper busbar is determined based on the difference between the two values.

[0046] The embodiments of this application can perform compensation tasks on the battery pack to decouple the coupling amount of the internal resistance voltage drop of the battery cell and the internal resistance voltage drop of the copper busbar, accurately obtain the actual voltage difference generated by the copper busbar of the battery pack, and provide a real and effective data basis for the subsequent accurate calculation of the internal resistance of the copper busbar.

[0047] In step S303, the internal resistance of the copper busbar of the battery pack is calculated based on the actual voltage difference generated by the copper busbar, so as to generate a voltage compensation value based on the internal resistance of the copper busbar.

[0048] It is understood that, in the embodiments of this application, the copper busbar internal resistance refers to the inherent resistance value of the copper busbar conductor used for inter-module connection within the battery pack. The voltage compensation value refers to the correction value used to offset the voltage drop caused by the copper busbar internal resistance. The correction value is added to the original sampled voltage to restore the true voltage of the battery cell.

[0049] In actual operation, variations in the torque applied during copper busbar installation and individual differences in the busbars can lead to variations in their internal resistance. Calculating the internal resistance based on the voltage difference generated by the actual copper busbar can minimize the impact of the bridging busbar on the individual unit voltage. Specifically, in this embodiment, the internal resistance of the copper busbar can be directly calculated based on the voltage difference generated by the actual copper busbar, combined with the synchronously acquired large current value flowing through the copper busbar during compensation tasks, using Ohm's law. After calculating the internal resistance, the BMS stores the copper busbar internal resistance value in non-volatile memory. In each subsequent power-on operation cycle of the vehicle, the BMS acquires the current charging / discharging current collected by the current sensor in real time and dynamically generates a voltage compensation value proportional to the real-time current magnitude.

[0050] The embodiments of this application can effectively eliminate the interference of the copper busbar internal resistance on the single cell voltage acquisition by accurately calculating the internal resistance of the copper busbar and generating the corresponding voltage compensation value, thereby improving the accuracy of the BMS system in estimating the battery state and thus improving the overall performance and safety of electric vehicles.

[0051] Optionally, in one embodiment of this application, the preset compensation conditions are: the battery management system is in an offline electrical inspection state; the charging current or discharging current of the battery pack meets the preset high current condition; the current sensor of the battery pack is fault-free; the battery management system has not performed overvoltage compensation; and the copper busbar resistance and cell internal resistance of the battery pack are both within the preset reasonable range.

[0052] It is understood that the preset high current condition in this application embodiment can be that the absolute value of the current is greater than the calibrated threshold, such as greater than 825A. The preset high current condition can be set by those skilled in the art according to the actual situation, and no specific limitation is made here. The preset reasonable range can be pre-calibrated according to the cell datasheet and copper busbar design parameters. For example, the cell internal resistance is between 80% and 120% of the typical value at room temperature, and the copper busbar resistance is within ±30% of the theoretically calculated value. The preset reasonable range can be set by those skilled in the art according to the actual situation, and no specific limitation is made here.

[0053] For example, in this embodiment of the application, the main control unit of the BMS can perform individual detection and logical judgment on each relevant parameter. Specifically, the BMS first reads the production line diagnostic command through the vehicle communication network to confirm that the vehicle is currently in the off-line electrical inspection condition. At the same time, the BMS collects the charging and discharging current values ​​from the current sensor in real time and compares them with a preset high current condition. The preset high current condition can be specifically set to an absolute current value greater than a certain calibrated threshold, such as greater than 825A, to ensure that the voltage drop on the copper busbar is sufficiently significant and the signal-to-noise ratio meets the identification requirements.

[0054] Furthermore, in this embodiment, the BMS can execute the self-diagnostic program of the current sensor to confirm that it is fault-free and that the output signal is valid. This embodiment can also use the BMS to query the compensation completion flag in the EEPROM to determine if overvoltage compensation has not been performed, ensuring that internal resistance identification is performed only once and avoiding duplicate overwriting of valid data. This embodiment can also use the BMS to perform a reasonableness check on the current estimated copper busbar resistance and cell internal resistance of the battery pack, confirming that they are both within a preset reasonable range. This preset reasonable range can be pre-calibrated based on the cell specifications and copper busbar design parameters; for example, the cell internal resistance should be between 80% and 120% of the typical value at room temperature, and the copper busbar resistance should be within ±30% of the theoretically calculated value. If any of the above conditions are not met, the compensation process is terminated and the system returns to a waiting state.

[0055] The embodiments of this application can ensure that the voltage compensation operation is performed under appropriate operating conditions by setting multiple judgment conditions, including operating conditions, current magnitude, sensor fault status, compensation execution records, and battery internal resistance parameters. This avoids misjudgment or incorrect compensation caused by performing compensation operation under unsuitable operating conditions, ensures the validity and reliability of the detection data in the voltage compensation task, and improves the reliability and applicability of the compensation strategy.

[0056] Optionally, in one embodiment of this application, performing a compensation task on the battery pack to obtain the actual voltage difference generated by the copper busbars of the battery pack includes: before performing the compensation task on the battery pack, acquiring at least one set of static voltage values ​​of the battery pack to determine a first voltage value of the battery pack based on the at least one set of static voltage values; during the performance of the compensation task on the battery pack, acquiring at least one set of discharged voltage values ​​of the battery pack to determine a second voltage value of the battery pack based on the at least one set of discharged voltage values; and calculating the actual voltage difference generated by the copper busbars of the battery pack based on the first voltage value and the second voltage value.

[0057] It is understood that the static voltage value in this embodiment refers to the voltage collected when the battery pack is in a static state with no charging or discharging current. At this time, no current flows through the copper busbar, and no voltage division occurs, thus directly reflecting the true voltage of the battery cell. The voltage value after discharge refers to the voltage collected when the battery pack is discharging under load. The voltage value after discharge includes both the battery cell voltage and the voltage division of the copper busbar. The first voltage value can be a reference voltage determined based on multiple sets of static sampling data by averaging or median filtering. The second voltage value can be the voltage determined by averaging or median filtering after multiple samplings of the same channel during a period of stable high current output.

[0058] In actual implementation, this embodiment of the application can control the battery pack to perform a standard high-current discharge or receive a standard high-current charge during the offline electrical inspection process. Before performing the compensation task, the BMS first samples the voltage acquisition channel containing the copper busbar through the individual cell voltage acquisition circuit when the battery pack is in a stable resting state (e.g., 5 seconds before discharge), obtaining at least one set of resting voltage values, and determines a first voltage value as a reference. Further, this embodiment of the application can, during the process of the battery pack discharging or charging with a high current (e.g., 2 seconds after the start of discharge), the BMS samples the same voltage acquisition channel again, obtaining at least one set of dynamic voltage values, and determines a second voltage value accordingly. This embodiment of the application can use the microprocessor inside the BMS to calculate the difference between the second voltage value and the first voltage value to remove the additional voltage drop caused by the current flowing through the copper busbar, thereby obtaining the actual voltage difference generated by the copper busbar.

[0059] like Figure 4 As shown in the embodiment of this application, a set of voltage values ​​V at rest can be stored. a(Continuous buffering, taking the value 5 seconds before discharge). At this time, since there is no current, neither the copper busbar nor the internal resistance of the cell will affect the collected individual cell voltage. Two seconds after the start of discharge, a set of voltage values ​​V is stored. b At this point, both the bridging copper busbar and the normal cell will be affected by internal resistance. The copper busbar cell is affected by the internal resistance of the battery cell and the internal resistance of the copper busbar, while the normal cell is only affected by the internal resistance of the battery cell. The voltage difference V between each cell is taken. c =|V a -V b |

[0060] The embodiments of this application can effectively separate the true voltage difference caused by the internal resistance of the copper busbar by collecting voltage values ​​in the static state and the discharge state before and after the compensation task is executed. This can eliminate the influence of irrelevant factors such as voltage fluctuations of the battery cell itself and environmental interference, providing a reliable data basis for the subsequent accurate calculation of the internal resistance of the copper busbar, and improving the accuracy and repeatability of the voltage difference measurement.

[0061] Optionally, in one embodiment of this application, calculating the internal resistance of the copper busbar of the battery pack based on the voltage difference generated by the actual copper busbar includes: calculating the internal resistance of the copper busbar based on the voltage difference generated by the actual copper busbar and the current value when the battery pack performs the compensation task; or, determining the corresponding resistance of the individual cell voltage affected by the copper busbar based on the voltage difference generated by the actual copper busbar, and calculating the internal resistance of the copper busbar based on the corresponding resistance and the average value of the cell internal resistance of the battery pack.

[0062] It is understood that the resistance corresponding to the single-cell voltage affected by the copper busbar in the embodiments of this application can be understood as the equivalent total resistance formed when the copper busbar and the cell are sampled together. The average internal resistance of the cell can be understood as the average value calculated after sampling the internal resistance of all normal cells in the battery pack.

[0063] In actual implementation, this embodiment can directly calculate the internal resistance of the copper busbar based on the voltage difference generated by the actual copper busbar and the synchronously acquired large current value flowing through the copper busbar during the compensation task, according to Ohm's law. That is, the internal resistance of the copper busbar is equal to the voltage difference generated by the actual copper busbar divided by the absolute value of the charging and discharging current at that moment. As another parallel implementation method, the BMS can also first calculate the ratio of voltage change to current on the voltage acquisition channel affected by the copper busbar, to obtain a total corresponding resistance including the internal resistance of the battery cell and the internal resistance of the copper busbar; based on the voltage change data of other normal battery cells in the battery pack that are not affected by the copper busbar under this large current condition, an average internal resistance of the battery cell is calculated. This embodiment can subtract the average internal resistance of the battery cell from the total corresponding resistance, and the difference is the internal resistance of the copper busbar.

[0064] For example, embodiments of this application can calculate the resistance value R=|V for a given current value. c / Current|. In this embodiment, the individual cell voltage affected by the copper busbar can also be denoted as R.t Calculate the internal resistance of a normal battery cell, and take the average value R. p (The average internal resistance of all normal cells in the current AFE can be used to prevent significant impact from abnormal data of individual cells.) The internal resistance of the copper busbar, i.e., the compensation resistor, is R = R t -R p The data is stored in EEPROM.

[0065] The embodiments of this application can calculate the internal resistance of the copper busbar by directly relating the voltage difference and current generated by the actual copper busbar, or by analyzing the difference between the resistance of the corresponding single cell voltage affected by the copper busbar and the internal resistance of the cell. This allows for selection of execution based on the actual data type obtained, adapting to different hardware acquisition conditions and different battery pack testing scenarios, improving versatility and fault tolerance, while ensuring that the internal resistance parameters of the copper busbar can be accurately obtained under different calculation methods.

[0066] Optionally, in one embodiment of this application, generating a voltage compensation value based on the internal resistance of the copper busbar includes: obtaining the current charging / discharging current of the battery pack; and calculating the voltage compensation value based on the internal resistance of the copper busbar and the current charging / discharging current.

[0067] It is understood that, in this embodiment of the application, the current charging / discharging current refers to the instantaneous current value flowing through the copper busbar of the battery pack, which is collected in real time by the current sensor during actual vehicle operation or charging. The voltage compensation value can be understood as a correction voltage that dynamically changes with the real-time current, used to offset the voltage drop on the copper busbar in real time.

[0068] In actual implementation, this embodiment allows the BMS to acquire the current charging / discharging current collected by the current sensor in real time during each subsequent power-on operation cycle of the vehicle. The stored copper busbar internal resistance is multiplied by the current charging / discharging current to dynamically generate a voltage compensation value proportional to the real-time current magnitude. Specifically, during each normal operation cycle after the vehicle's power-on start, the BMS application executes a voltage compensation calculation process at a fixed task cycle, such as every 10 milliseconds or 100 milliseconds. Within each cycle, the BMS first reads the current current value output by the current sensor via an analog-to-digital converter and determines the sign of the current based on the charging / discharging direction. It then reads the pre-stored copper busbar internal resistance value from the EEPROM and performs a multiplication operation, multiplying the current current value by the copper busbar internal resistance value to obtain the voltage compensation value to be applied at the current moment. This voltage compensation value is then applied to the real-time correction of the individual cell voltage acquisition value. This compensation value is directly added to or subtracted from the original voltage data of the acquisition channel containing the copper busbar to obtain the true cell voltage.

[0069] For example, in the embodiments of this application, during normal use of the battery pack, under discharge conditions, the single-cell voltage value = AFE sampled value + compensation resistor R Current (no compensation if current value is abnormal), during charging, the single-cell voltage value = AFE acquisition value - compensation resistor R Current. In this embodiment, the characteristic of the copper busbar internal resistance not being fixed is fully considered. Instead of using a fixed copper busbar internal resistance value, the internal resistance of the copper busbar is calculated based on the voltage rise and voltage drop during the charging and discharging process of the battery pack, and stored in the software's EEPROM. Each time power is applied, the data is read and compensation is performed in real time according to the current magnitude to ensure the accuracy of the compensation to the maximum extent.

[0070] The embodiments of this application can dynamically generate voltage compensation values ​​that match the real-time operating conditions by using the identified internal resistance of the copper busbar and the real-time collected current charging and discharging current during actual vehicle operation. This ensures that the influence of the internal resistance of the copper busbar on the acquisition of individual cell voltage can be effectively eliminated under different load conditions, so that the battery state estimation can continuously obtain true individual cell voltage information, thereby improving the voltage acquisition accuracy and battery state estimation reliability of the battery management system under various operating conditions.

[0071] According to the voltage compensation method for the battery management system proposed in this application, when the battery management system meets the compensation conditions, a compensation task is performed on the battery pack to collect the actual voltage difference of the copper busbars. Based on the actual voltage difference, the internal resistance of the copper busbars is calculated, and a voltage compensation value associated with the real-time current is generated. This minimizes the impact of the bridging copper busbars on the individual cell voltage, enabling the battery management system to obtain the true individual cell voltage after eliminating the voltage drop effect of the copper busbars. This effectively improves the accuracy of battery state estimation, such as state of charge and state of health, ensuring the overall performance and safety of the electric vehicle. Therefore, this solves the problem in related technologies where, due to the neglect of the internal resistance of the copper busbars, a significant voltage difference is caused when the battery pack undergoes high-current charging and discharging, resulting in inaccurate individual cell voltage data and errors in the BMS system's estimation of the battery state.

[0072] Next, the voltage compensation device for the battery management system proposed according to the embodiments of this application is described with reference to the accompanying drawings.

[0073] Figure 5 This is a schematic diagram of the voltage compensation device of the battery management system according to an embodiment of this application.

[0074] like Figure 5 As shown, the voltage compensation device 10 of the battery management system includes: a detection module 100, an acquisition module 200, and a compensation module 300.

[0075] The detection module 100 is used to detect whether the battery management system meets the preset compensation conditions.

[0076] The acquisition module 200 is used to perform a compensation task on the battery pack when the battery management system is detected to meet the preset compensation conditions, so as to obtain the actual pressure difference generated by the copper busbars of the battery pack.

[0077] The compensation module 300 calculates the internal resistance of the copper busbars in the battery pack based on the actual voltage difference generated by the copper busbars, and generates a voltage compensation value based on the internal resistance of the copper busbars.

[0078] Optionally, in one embodiment of this application, the preset compensation conditions are: the battery management system is in an offline electrical inspection state; the charging current or discharging current of the battery pack meets the preset high current condition; the current sensor of the battery pack is fault-free; the battery management system has not performed overvoltage compensation; and the copper busbar resistance and cell internal resistance of the battery pack are both within the preset reasonable range.

[0079] Optionally, in one embodiment of this application, the acquisition module 200 includes: a first determining unit, a second determining unit, and a first calculating unit.

[0080] The first determining unit is used to collect at least one set of static voltage values ​​of the battery pack before performing a compensation task on the battery pack, so as to determine a first voltage value of the battery pack based on the at least one set of static voltage values.

[0081] The second determining unit is used to collect at least one set of discharged voltage values ​​of the battery pack during the process of performing a compensation task on the battery pack, so as to determine a second voltage value of the battery pack based on the at least one set of discharged voltage values.

[0082] The first calculation unit is used to calculate the voltage difference generated by the actual copper busbar of the battery pack based on the first voltage value and the second voltage value.

[0083] Optionally, in one embodiment of this application, the compensation module 300 includes a second calculation unit and a third calculation unit.

[0084] The second calculation unit is used to calculate the internal resistance of the copper busbar based on the actual pressure difference generated by the copper busbar and the current value when the battery pack performs the compensation task.

[0085] The third calculation unit is used to determine the corresponding resistance of the cell voltage affected by the copper busbar based on the actual voltage difference generated by the copper busbar, and to calculate the internal resistance of the copper busbar based on the corresponding resistance and the average internal resistance of the battery pack cells.

[0086] Optionally, in one embodiment of this application, the compensation module 300 includes a current acquisition unit and a fourth calculation unit.

[0087] The current acquisition unit is used to acquire the current charging / discharging current of the battery pack.

[0088] The fourth calculation unit is used to calculate the voltage compensation value based on the internal resistance of the copper busbar and the current charging / discharging current.

[0089] It should be noted that the foregoing explanation of the voltage compensation method embodiment for the battery management system also applies to the voltage compensation device of the battery management system in this embodiment, and will not be repeated here.

[0090] The voltage compensation device for the battery management system proposed in this application can perform a compensation task on the battery pack to collect the actual voltage difference of the copper busbars when the battery management system meets the compensation conditions. Based on the actual voltage difference, the internal resistance of the copper busbars is calculated, and a voltage compensation value associated with the real-time current is generated. This minimizes the impact of the bridging copper busbars on the individual cell voltage, enabling the battery management system to obtain the true individual cell voltage after eliminating the voltage drop effect of the copper busbars. This effectively improves the accuracy of battery state estimation, such as state of charge and state of health, ensuring the overall performance and safety of the electric vehicle. Therefore, this solves the problem in related technologies where, due to the neglect of the internal resistance of the copper busbars, a significant voltage difference is caused when the battery pack undergoes high-current charging and discharging, resulting in inaccurate individual cell voltage data and errors in the BMS system's estimation of the battery state.

[0091] Figure 6 A schematic diagram of the structure of a vehicle provided in an embodiment of this application. The vehicle may include: The memory 601, the processor 602, and the computer program stored on the memory 601 and capable of running on the processor 602.

[0092] When the processor 602 executes the program, it implements the voltage compensation method of the battery management system provided in the above embodiments.

[0093] Furthermore, the vehicle also includes: Communication interface 603 is used for communication between memory 601 and processor 602.

[0094] The memory 601 is used to store computer programs that can run on the processor 602.

[0095] The memory 601 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0096] If the memory 601, processor 602, and communication interface 603 are implemented independently, then the communication interface 603, memory 601, and processor 602 can be interconnected via a bus to complete communication between them. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. The bus can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 6 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0097] Optionally, in a specific implementation, if the memory 601, processor 602, and communication interface 603 are integrated on a single chip, then the memory 601, processor 602, and communication interface 603 can communicate with each other through an internal interface.

[0098] The processor 602 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application.

[0099] This application also provides a non-volatile computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the voltage compensation method of the battery management system described above.

[0100] This application also provides a computer program product on which a computer program is stored, which, when executed by a processor, implements the voltage compensation method of the battery management system described above.

[0101] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0102] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0103] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0104] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0105] It should be understood that the various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. If implemented in hardware, as in another embodiment, it can be implemented using any one or more of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0106] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0107] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0108] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A voltage compensation method for a battery management system, characterized in that, Includes the following steps: Check whether the battery management system meets the preset compensation conditions; If the battery management system is found to meet the preset compensation conditions, a compensation task is performed on the battery pack to obtain the actual pressure difference generated by the copper busbars of the battery pack. The internal resistance of the copper busbar in the battery pack is calculated based on the actual pressure difference generated by the copper busbar, and a voltage compensation value is generated based on the internal resistance of the copper busbar.

2. The method according to claim 1, characterized in that, The preset compensation condition is: The battery management system is in the offline electrical inspection condition; The charging current or discharging current of the battery pack meets the preset high current condition. The current sensor of the battery pack is fault-free; The battery management system did not perform overvoltage compensation. The resistance of the copper busbar and the internal resistance of the battery cell in the battery pack are both within a preset reasonable range.

3. The method according to claim 1, characterized in that, The step of performing a compensation task on the battery pack to obtain the actual pressure difference generated by the copper busbars of the battery pack includes: Before performing the compensation task on the battery pack, at least one set of static voltage values ​​of the battery pack are collected to determine a first voltage value of the battery pack based on the at least one set of static voltage values; During the compensation task performed on the battery pack, at least one set of discharged voltage values ​​of the battery pack are collected to determine a second voltage value of the battery pack based on the at least one set of discharged voltage values. Based on the first voltage value and the second voltage value, the actual pressure difference generated by the copper busbar of the battery pack is calculated.

4. The method according to claim 1 or 3, characterized in that, The calculation of the internal resistance of the copper busbar of the battery pack based on the pressure difference generated by the actual copper busbar includes: The internal resistance of the copper busbar is calculated based on the actual pressure difference generated by the copper busbar and the current value of the battery pack when performing the compensation task. Alternatively, the resistance of the individual cell voltage affected by the copper busbar can be determined based on the voltage difference generated by the actual copper busbar, and the internal resistance of the copper busbar can be calculated based on the corresponding resistance and the average internal resistance of the cells in the battery pack.

5. The method according to claim 1, characterized in that, The step of generating a voltage compensation value based on the internal resistance of the copper busbar includes: Obtain the current charging / discharging current of the battery pack; The voltage compensation value is calculated based on the internal resistance of the copper busbar and the current charging / discharging current.

6. A voltage compensation device for a battery management system, characterized in that, include: The detection module is used to detect whether the battery management system meets the preset compensation conditions; The acquisition module is used to perform a compensation task on the battery pack when the battery management system is detected to meet the preset compensation conditions, so as to obtain the actual pressure difference generated by the copper busbar of the battery pack. The compensation module is used to calculate the internal resistance of the copper busbar of the battery pack based on the actual pressure difference generated by the copper busbar, so as to generate a voltage compensation value based on the internal resistance of the copper busbar.

7. The apparatus according to claim 6, characterized in that, The preset compensation condition is: The battery management system is in the offline electrical inspection condition; The charging current or discharging current of the battery pack meets the preset high current condition. The current sensor of the battery pack is fault-free; The battery management system did not perform overvoltage compensation. The resistance of the copper busbar and the internal resistance of the battery cell in the battery pack are both within a preset reasonable range.

8. A vehicle, characterized in that, include: A memory, a processor, and a computer program stored in the memory and capable of running on the processor, the processor executing the program to implement the voltage compensation method of the battery management system as described in any one of claims 1-5.

9. A non-volatile computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the voltage compensation method of the battery management system as described in any one of claims 1-5.

10. A computer program product, comprising a computer program, characterized in that, The computer program is executed to implement the voltage compensation method of the battery management system as described in any one of claims 1-5.

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