A method, apparatus and device for determining state of charge of a battery system

Abstract

The application discloses a method, device and equipment for determining the state of charge of a battery system, the battery system comprising a plurality of parallel battery branches, the method comprising: determining a state code corresponding to each battery branch based on the operation data of each battery branch; wherein the state code is used to identify whether the battery branch is in an effective working state; obtaining branch state of charge data of each battery branch; and determining the system state of charge of the battery system based on the branch state of charge data of each battery branch and the corresponding state code. The application determines the corresponding state code according to the operation data of each battery branch, and determines the system state of charge based on the branch state of charge data of each battery branch and the corresponding state code, thereby overcoming the problem that the system state of charge estimation accuracy is insufficient due to the fact that the branch operation state difference is not considered in the prior art, and improving the system state of charge estimation accuracy.

Description

Technical Field

[0001] This application relates to the field of battery management technology, and in particular to a method, apparatus and device for determining the state of charge of a battery system. Background Technology

[0002] State of charge (SOC) estimation is a core component of battery management technology, directly impacting the safe operation, energy optimization, and lifespan management of the battery system. In multi-branch parallel battery systems, accurate characterization of the system-level SOC is fundamental to ensuring reliable operation, and its estimation accuracy directly affects the energy utilization efficiency and operational safety of the battery system.

[0003] Currently, most battery management systems estimate the state of charge (SOC) of a multi-branch parallel battery system by directly calculating the SOC based on the SOC data of each branch, without considering the dynamic differences in the operating states of each branch. This results in the SOC data of some branches interfering with the SOC estimation, leading to insufficient accuracy in the SOC estimation. Summary of the Invention

[0004] This application provides a method, apparatus, and device for determining the state of charge of a battery system, which addresses the problem of insufficient accuracy in estimating the state of charge of a system in the prior art.

[0005] The technical solution adopted in this application is as follows: In a first aspect, this application provides a method for determining the state of charge (SOC) of a battery system, the battery system comprising multiple parallel battery branches, the method comprising: Based on the operating data of each battery branch, the status code corresponding to each battery branch is determined; the status code is used to identify whether the battery branch is in an effective working state. Obtain the branch charge data of each battery branch; Based on the branch charge data and corresponding state codes of each battery branch, the system state of charge of the battery system is determined.

[0006] In one alternative approach of the first aspect, based on the operating data of each battery branch, the state code corresponding to each battery branch is determined, including: Based on the operating data of each battery branch and the corresponding preset threshold range, the working state of each battery branch is determined; wherein, the operating data includes at least one of current data, voltage data and temperature data, and the preset threshold range includes at least one of the corresponding preset current range, preset voltage range and preset temperature range. The status code corresponding to each battery branch is determined based on the working status.

[0007] In one alternative approach of the first aspect, the operating state of each battery branch is determined based on its operating data and the corresponding preset threshold range, including: The operating data of each battery branch is compared with the corresponding preset threshold range; If the operating data of the battery branch exceeds the corresponding preset threshold range, the working state of the battery branch is determined to be invalid; otherwise, the working state of the battery branch is determined to be valid.

[0008] In one alternative of the first aspect, each battery branch includes multiple cells connected in series; Obtain the branch charge data for each battery branch, including: Obtain voltage data of multiple cells in each battery branch; Based on voltage data, the first cell with the highest voltage and the second cell with the lowest voltage in each battery branch are determined. Obtain the first charge value of the first battery cell and the second charge value of the second battery cell; If the preset correction conditions are met, the first charge value and the second charge value are corrected based on the preset mapping table to obtain the corresponding maximum charge value and minimum charge value. Otherwise, the first charge value is taken as the maximum charge value, and the second charge value is taken as the minimum charge value; Based on the maximum charge value, the minimum charge value, the preset maximum charge threshold, and the preset minimum charge threshold, determine the first weight corresponding to the maximum charge value and the second weight corresponding to the minimum charge value; Based on the maximum charge value, minimum charge value, first weight, and second weight, the branch charge data of each battery branch is calculated.

[0009] In one alternative scheme of the first aspect, the first charge value of the first battery cell and the second charge value of the second battery cell are corrected based on a preset mapping table to obtain the corresponding maximum charge value and minimum charge value, including: Obtain the first voltage of the first battery cell and the second voltage of the second battery cell; The maximum charge value is determined based on the first voltage and a preset mapping table; The minimum charge value is determined based on the second voltage and a preset mapping table.

[0010] In one alternative approach of the first aspect, the system state of charge of the battery system is determined based on the branch charge data and corresponding state codes of each battery branch, including: From each battery branch, the battery branch whose working state is represented by the state code is an effective state is determined as the effective branch; Based on the branch charge data and rated capacity of the effective branches, the system state of charge of the battery system is determined.

[0011] In one alternative of the first aspect, the system state of charge of the battery system is determined based on the branch charge data and rated capacity of the effective branches, including: The sum of the products of the branch charge data and the rated capacity of each effective branch is used as the first parameter; The sum of the rated capacities of all effective branches is used as the second parameter; The ratio between the first parameter and the second parameter is taken as the system state of charge of the battery system.

[0012] In one alternative to the first aspect, the method further includes: Receive a status calibration command for at least one of the battery branches; Based on the status calibration command, the status code of the corresponding battery branch is updated to either the first code that identifies the valid working state or the second code that identifies the invalid working state. Receive a recovery command for at least one of the battery branches; Based on the recovery command, the status code of the corresponding battery branch is restored to the preset code.

[0013] Secondly, this application provides a battery system state-of-charge determination device, the battery system including multiple parallel battery branches, the device comprising: The status coding module is used to determine the status code corresponding to each battery branch based on the operating data of each battery branch; the status code is used to identify whether the battery branch is in an effective working state. The data acquisition module is used to acquire the branch charge data of each battery branch; The charge calculation module is used to determine the system state of charge of the battery system based on the branch charge data of each battery branch and the corresponding state code.

[0014] In one alternative to the second aspect, the state coding module includes: The branch status determination unit is used to determine the working status of each battery branch based on the operating data of each battery branch and the corresponding preset threshold range; wherein, the operating data includes at least one of current data, voltage data and temperature data, and the preset threshold range includes at least one of the corresponding preset current range, preset voltage range and preset temperature range. The status coding configuration unit is used to determine the status code corresponding to each battery branch based on the working status.

[0015] In one alternative to the second aspect, the state coding module includes: The data comparison unit is used to compare the operating data of each battery branch with the corresponding preset threshold range; The state determination unit is used to determine that the working state of the battery branch is invalid if the operating data of the battery branch exceeds the corresponding preset threshold range; otherwise, it determines that the working state of the battery branch is valid.

[0016] In one alternative of the second aspect, each battery branch includes multiple cells connected in series; The data acquisition module includes: Voltage data acquisition unit, used to acquire voltage data of multiple cells in each battery branch; The extreme value cell determination unit is used to determine the first cell with the highest voltage and the second cell with the lowest voltage in each battery branch based on voltage data. An extreme charge acquisition unit is used to acquire the first charge value of the first battery cell and the second charge value of the second battery cell. An extreme charge correction unit is used to correct the first charge value and the second charge value respectively based on a preset mapping table if a preset correction condition is met, so as to obtain the corresponding maximum charge value and minimum charge value. Otherwise, the first charge value is taken as the maximum charge value, and the second charge value is taken as the minimum charge value; The extreme value weight determination unit is used to determine the first weight corresponding to the maximum charge value and the second weight corresponding to the minimum charge value based on the maximum charge value, the minimum charge value, the preset maximum charge threshold, and the preset minimum charge threshold. The branch charge calculation unit is used to calculate the branch charge data of each battery branch based on the maximum charge value, the minimum charge value, the first weight, and the second weight.

[0017] In one alternative embodiment of the second aspect, the data acquisition module includes: An extreme voltage acquisition unit is used to acquire the first voltage of the first battery cell and the second voltage of the second battery cell. The maximum charge mapping unit is used to determine the maximum charge value based on the first voltage and a preset mapping table; The minimum charge mapping unit is used to determine the minimum charge value based on the second voltage and a preset mapping table.

[0018] In one alternative embodiment of the second aspect, the charge calculation module includes: The effective branch screening unit is used to identify the battery branches whose working state represented by the state code is an effective state from each battery branch as effective branches. The system charge determination unit is used to determine the system state of charge of the battery system based on the branch charge data and rated capacity of the effective branches.

[0019] In one alternative embodiment of the second aspect, the charge calculation module includes: The weighted numerator calculation unit is used to sum the product of the branch charge data and the rated capacity of each effective branch as the first parameter; The total capacity calculation unit is used to use the sum of the rated capacities of each effective branch as the second parameter; The weighted ratio calculation unit is used to take the ratio between the first parameter and the second parameter as the system state of charge of the battery system.

[0020] In an alternative embodiment of the second aspect, the method further includes a calibration and recovery module, which comprises: A calibration instruction receiving unit is used to receive a status calibration instruction for at least one of the battery branches in each battery branch. The status coding calibration unit is used to update the status code of the corresponding battery branch to a first code that identifies a valid working state or a second code that identifies an invalid working state based on the status calibration command. A recovery command receiving unit is used to receive a recovery command for at least one of the battery branches. The status code recovery unit is used to restore the status code of the corresponding battery branch to the preset code based on the recovery command.

[0021] Thirdly, this application provides an electronic device including a memory and a processor. The memory is used to store computer programs or instructions that, when executed by the processor, implement the method described in the first aspect or any of the alternative solutions of the first aspect.

[0022] The beneficial effects of the technical solutions provided in some embodiments of this specification include at least the following: This application determines the corresponding state code by acquiring the operating data of each battery branch, and determines the system state of charge (SOC) of the battery system based on the branch charge data and its corresponding state code. Unlike existing technologies that directly fuse and calculate the SOC of each branch, this scheme identifies the operating state of each battery branch based on its operating data, uses the state code to reflect whether the branch is in an effective operating state, and then combines the branch charge data with the corresponding state code to determine the system SOC. This achieves automatic correlation between the branch operating state and the system SOC estimation, enabling the calculation of the system SOC to reflect the differences in the actual operating states of each branch, suppressing the interference of ineffective operating branch data on the system SOC, and improving the accuracy of the system SOC estimation. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 A flowchart of a method for determining the state of charge of a battery system provided in an embodiment of this application; Figure 2 A schematic diagram of the structure of the battery system state-of-charge determination device provided in an embodiment of this application; Figure 3 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0025] Embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0026] The accompanying drawings illustrate various structural schematics according to embodiments of the present disclosure. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0027] The following is a brief explanation of the terms used in this application: NVM (Non-Volatile Memory): A storage medium that retains stored data even after power failure, used in this application to store the factory default configuration of battery branch status codes.

[0028] UDS (Unified Diagnostic Services): A standardized communication protocol applied to vehicle diagnostic systems, used in this application for temporary calibration of the working status of battery branches during after-sales maintenance.

[0029] Coulombic efficiency: The ratio between the actual amount of electricity involved in the electrochemical reaction during the charging and discharging process and the theoretically calculated amount of electricity. In this application, it is used as a correction factor for the amount of electricity when calculating the state of charge using the ampere-hour integral method, to compensate for irreversible electricity loss during the charging and discharging process.

[0030] With the rapid development of new energy vehicle technology and the continuous improvement of the demand for intelligent battery management systems, accurate estimation of the state of charge (SOC) of multi-branch parallel battery systems has become an important technical direction for ensuring the safe operation of battery systems and optimizing energy management. Currently, the SOC estimation of multi-branch parallel battery systems generally adopts the traditional technical architecture of directly fusing and calculating the SOC data of each branch. In actual operation, due to differences in the operating conditions and state changes of each branch, the actual working state of each battery branch varies significantly. However, when dealing with these complex scenarios involving multi-branch state perception, working state assessment, and system-level SOC fusion, existing solutions still use a model where data from each branch is uniformly included in the calculation without distinction. This causes the SOC data of ineffective working branches to interfere with the system's SOC, reducing the accuracy of system SOC estimation and failing to achieve real-time linkage response between branch working states and system SOC estimation.

[0031] To address the aforementioned technical problems, the inventive concept of this application is as follows: by acquiring the operating data of each battery branch to determine the corresponding state code to identify whether the battery branch is in an effective working state, and based on the branch charge data of each battery branch and its corresponding state code, the system state of charge of the battery system is determined, thereby realizing dynamic coordination and accurate calculation of branch working state and system state of charge estimation, overcoming the defect of insufficient system state of charge estimation accuracy under the traditional unified fusion calculation mode, ensuring real-time synchronization of branch state perception and system state of charge estimation under complex working conditions, and improving the estimation accuracy of system state of charge.

[0032] The technical solutions of this application and how they solve the aforementioned technical problems will be described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0033] It should be noted that the implementer of this application may be, but is not limited to, a battery management system, a battery management controller, a vehicle controller, a power domain controller, an on-board central computing platform, etc.

[0034] refer to Figure 1 , Figure 1 A flowchart illustrating the method for determining the state of charge of a battery system provided in this application embodiment. Figure 1 As shown, the battery system includes multiple parallel battery branches, and the method for determining the state of charge of the battery system includes at least the following steps: S101: Based on the operating data of each battery branch, determine the status code corresponding to each battery branch.

[0035] The status code is used to identify whether the battery branch is in a valid working state.

[0036] Specifically, during actual operation, the operating data (such as current, voltage, and temperature) of each battery branch reflects its current working status. By analyzing the operating data of each branch, for example, comparing it with corresponding preset threshold ranges, it can be determined whether each branch is in a normal and effective working state. Based on this determination, a corresponding status code is assigned to each branch. This status code is used to identify whether the branch is currently in an effective or ineffective working state, thus providing a basis for calculating the branch status in subsequent system state of charge calculations.

[0037] For example, the above status coding can use a binary bitmap to represent the working status of each branch. This coding ensures that each code value uniquely corresponds to a branch combination. The rightmost bit corresponds to the first branch, and from right to left, they correspond to the second, third, and fourth branches respectively. This arrangement is because in binary representation, the rightmost bit is the least significant bit, and the branch number and bit number form a one-to-one intuitive relationship, facilitating quick identification and parsing. For instance, when all four branches are in a valid working state, the status code is 1111 (corresponding to a code value of 15); when the first branch exits due to a fault, its corresponding least significant bit changes from 1 to 0, and the status code is updated to 1110 (corresponding to a code value of 14). The working status of the first branch can be directly determined by observing the value of the rightmost bit.

[0038] S103: Obtain the branch charge data of each battery branch.

[0039] Specifically, branch charge data is used to characterize the current state of charge (SOC) of each battery branch. When acquiring branch charge data, the battery management system can collect data such as voltage and current of the cells in each branch, and determine the corresponding branch charge data based on a preset mapping relationship or integral calculation method.

[0040] S105: Determine the system state of charge of the battery system based on the branch charge data and corresponding state codes of each battery branch.

[0041] Specifically, after obtaining the branch charge data and status codes of each branch, the effective branches with valid operating states are first selected from all branches based on the status codes. Subsequently, a weighted fusion calculation is performed based on the branch charge data and rated capacity of these effective branches to determine the system state of charge of the battery system.

[0042] Thus, this application determines the state code based on the operating data of each battery branch to identify the effective working state of the branch, and performs system-level state of charge calculation by combining the branch charge data with the corresponding state code, thereby realizing accurate estimation of the state of charge of a multi-branch parallel battery system. This overcomes the problem of insufficient system state of charge estimation accuracy caused by not distinguishing the working state of the branches in the prior art, and improves the estimation accuracy of the system state of charge.

[0043] In some embodiments, based on the operating data of each battery branch, the state code corresponding to each battery branch is determined, including: Based on the operating data of each battery branch and the corresponding preset threshold range, the working state of each battery branch is determined; wherein, the operating data includes at least one of current data, voltage data and temperature data, and the preset threshold range includes at least one of the corresponding preset current range, preset voltage range and preset temperature range. The status code corresponding to each battery branch is determined based on the working status.

[0044] Specifically, taking a multi-branch parallel battery system for commercial vehicles as an example, the battery management system continuously monitors the real-time operating data of each branch. For instance, if a branch experiences abnormal heat dissipation causing the cell temperature to exceed the preset upper limit of 60°C, or if a circuit fault causes the branch current to exceed the preset safe current threshold, or if a single cell damage causes the branch's total voltage to drop to the preset lower voltage limit, the system determines that the branch is no longer functioning properly and is in an invalid state. Conversely, if a branch's temperature remains within the normal range, its current is within a stable charging and discharging range, and its voltage does not fluctuate abnormally, then the branch is determined to be in a valid operating state. Subsequently, the system generates a concise status identifier for each branch: for example, code "1" indicates that the branch is currently operating normally, and its data can be used for subsequent calculations; code "0" indicates that the branch has abnormally exited and needs to be excluded. In this way, by converting physical quantities such as temperature, current, and voltage into intuitive status identifiers, the system can quickly identify which branches are in a valid operating state, providing a clear selection basis for accurately calculating the overall state of charge.

[0045] In view of this, the embodiments of this application compare the operating data with the preset safety threshold, transforming the complex physical state into a concise working state identifier, thereby realizing rapid and automatic troubleshooting of faulty branches. The available status of each branch can be updated in real time without manual intervention, thus ensuring that the subsequent calculation of the system's state of charge is based only on the normally operating branches, avoiding interference from abnormal branches with the overall estimation results.

[0046] In some embodiments, the status code is a uint8 type signal, where the lower 4 bits (bit0~bit3) correspond to the operating status of the four battery branches. A bit of 1 indicates that the corresponding branch is in an active operating state, and a bit of 0 indicates that the corresponding branch is in an inactive operating state. For example, when all four branches are active, the status code is 1111 (binary); when branch 1 fails, the status code is updated to 1110 (binary). Based on this bit encoding mechanism, the same algorithm framework supports any combination of 1 / 2 / 3 / 4 battery branches. The total current and total capacity are automatically calculated and adapted according to the status code, enabling reuse across multiple vehicle platforms without modifying the software code.

[0047] In some embodiments, the total system current and total system capacity of the battery system are adaptively determined based on the state coding of each branch, and the calculation formula is as follows:

[0048]

[0049] in, For the total current, Let i be the current in branch i. For total capacity, The rated capacity of branch i, The weighting factor for branch i is determined by the corresponding state code: when the state code indicates that branch i is in an effective working state, =1; otherwise =0. In this way, the total current and total capacity are automatically calculated and adapted to the number of effective branches, without the need for manual parameter modification or recalibration.

[0050] In some embodiments, the operating state of each battery branch is determined based on the operating data of each battery branch and the corresponding preset threshold range, including: The operating data of each battery branch is compared with the corresponding preset threshold range; If the operating data of the battery branch exceeds the corresponding preset threshold range, the working state of the battery branch is determined to be invalid; otherwise, the working state of the battery branch is determined to be valid.

[0051] Specifically, taking a four-branch parallel battery system for commercial vehicles as an example, the battery management system continuously monitors the temperature, voltage, and current data of each branch. For instance, during vehicle operation, if the cell temperature in the first branch continuously rises above the preset upper limit of 60°C due to a cooling fan malfunction, the system determines that the branch is in an invalid state. If the voltage of the second branch drops below the preset lower limit due to aging of individual cells, the system also determines that the branch is invalid. If the third branch experiences a sudden large current surge due to poor wiring contact, exceeding the preset safe current range, the system also marks it as invalid. For the fourth branch, where all operating data are within the normal range, the system determines that it is in a valid working state.

[0052] Therefore, the embodiments of this application realize the rapid and automatic identification of faulty branches by directly comparing the real-time collected physical quantities with the preset safety boundary. Without relying on complex model calculations or manual diagnosis, it can accurately distinguish between valid and invalid branches at the first time an anomaly occurs, providing a reliable state screening basis for the accurate calculation of the subsequent system charge state.

[0053] In some embodiments, when the operating data of a battery branch exceeds the corresponding preset threshold range, the battery management system automatically updates the status code of the corresponding battery branch to a code that identifies an invalid operating state. For example, when a branch's temperature exceeds a preset upper limit due to abnormal heat dissipation, or when the current exceeds a preset current range due to a line fault, the system automatically clears the corresponding bit (i.e., the code value) in the status code of that branch, causing the faulty branch to immediately exit the system's state of charge calculation, thereby supporting the safe operation of commercial vehicles in limp-riding conditions where some branches fail and the remaining branches continue driving.

[0054] In some embodiments, each battery branch includes multiple cells connected in series; Obtain the branch charge data for each battery branch, including: Obtain voltage data of multiple cells in each battery branch; Based on voltage data, the first cell with the highest voltage and the second cell with the lowest voltage in each battery branch are determined. Obtain the first charge value of the first battery cell and the second charge value of the second battery cell; If the preset correction conditions are met, the first charge value and the second charge value are corrected based on the preset mapping table to obtain the corresponding maximum charge value and minimum charge value. Otherwise, the first charge value is taken as the maximum charge value, and the second charge value is taken as the minimum charge value; Based on the maximum charge value, the minimum charge value, the preset maximum charge threshold, and the preset minimum charge threshold, determine the first weight corresponding to the maximum charge value and the second weight corresponding to the minimum charge value; Based on the maximum charge value, minimum charge value, first weight, and second weight, the branch charge data of each battery branch is calculated.

[0055] Specifically, taking a commercial vehicle battery branch as an example, this branch consists of dozens of individual battery cells connected in series. The battery management system acquires the voltage data of each cell in real time through a voltage acquisition line and filters out the cell with the highest voltage and the cell with the lowest voltage. Assume that the cell with the highest voltage in this branch has a preliminary estimated charge of approximately 90%, and the cell with the lowest voltage has a charge of approximately 20%. If the vehicle has been stationary for more than a set time and the current has stabilized, meeting the preset correction conditions, the system calls the preset voltage-charge mapping table and, combined with parameters such as the current temperature, corrects the two charge values ​​to obtain the corrected maximum and minimum charge values. If the vehicle is in dynamic motion and does not meet the correction conditions, the preliminary estimated charge values ​​are directly used as the maximum and minimum charge values. Subsequently, the system compares these two charge values ​​with preset safety thresholds (such as overcharge and over-discharge thresholds) and assigns them weights accordingly—usually, a higher weight is assigned to the minimum charge value to highlight the constraint effect of the safety boundary cell on the overall state of the branch. Finally, by weighting the maximum and minimum charge values ​​according to their respective weights, the current branch charge data of that branch can be obtained.

[0056] Therefore, this application embodiment uses the state of charge of the cell with extreme voltage in the branch as the basis for calculation, and combines correction conditions and weight allocation mechanism to achieve a refined characterization of the state of charge of the series cell group. It takes into account the consistency differences of the cells in the branch and highlights the influence weight of the cells at the safety boundary, thereby improving the accuracy and safety of the branch charge data.

[0057] In some embodiments, the branch charge data described above are determined based on the ampere-hour integration method. For each battery branch, its true state of charge is calculated using the following formula:

[0058] in, Let be the actual state of charge of branch i at time t. Let Δt be the current in branch i, and Δt be the sampling time interval. Let η be the rated capacity of branch i, and η be the coulombic efficiency. Through the above integral calculation, the changes in the state of charge of each branch due to charging and discharging can be tracked in real time.

[0059] In some embodiments, the first charge value of the first battery cell and the second charge value of the second battery cell are corrected based on a preset mapping table to obtain the corresponding maximum charge value and minimum charge value, including: Obtain the first voltage of the first battery cell and the second voltage of the second battery cell; The maximum charge value is determined based on the first voltage and a preset mapping table; The minimum charge value is determined based on the second voltage and a preset mapping table.

[0060] The preset mapping table is used to characterize the mapping relationship between the open-circuit voltage and the state of charge (i.e., the remaining power) of the battery cell. The higher the voltage, the more power is left.

[0061] Specifically, taking a certain battery branch as an example, when the vehicle is turned off and parked for more than a set time and the battery current approaches zero, the system determines that the correction condition is met. At this time, the system reads the voltage value of the highest voltage cell (e.g., 3.35 volts) and the voltage value of the lowest voltage cell (e.g., 3.05 volts) in that branch. Since there is a stable correspondence between voltage and remaining charge in the battery's resting state, the system calls a pre-calibrated voltage-charge mapping table, mapping 3.35 volts to approximately 92% of the remaining charge, as the maximum charge value of that branch; and mapping 3.05 volts to approximately 18% of the remaining charge, as the minimum charge value of that branch. In this way, by directly utilizing the correspondence between the resting voltage of the extreme cells and the mapping table, the corrected maximum and minimum charge values ​​can be quickly obtained, replacing the preliminary charge values ​​previously estimated by integration, thereby reducing the impact of long-term accumulated errors on the branch's charge state judgment.

[0062] Therefore, this embodiment of the application utilizes the direct correspondence between the voltage of the extreme cell in the static state and the preset mapping table to perform offline correction of the preliminary charge value, effectively eliminating the long-term accumulated estimation error of the integral method, improving the accuracy of the maximum and minimum charge values, and providing reliable basic data for the accurate calculation of subsequent branch charge data.

[0063] In some embodiments, the aforementioned preset mapping table is an open-circuit voltage and state of charge lookup table (OCV-SOC lookup table), and the coulombic efficiency is configured according to the battery chemistry system. By changing the corresponding open-circuit voltage and state of charge lookup table and coulombic efficiency parameters, the above method can be directly adapted to lithium iron phosphate batteries, ternary lithium batteries, sodium-ion batteries, and other commercial vehicle power battery systems, achieving cross-system reuse without modifying the core algorithm logic.

[0064] In some embodiments, the system state of charge of the battery system is determined based on the branch charge data of each battery branch and the corresponding state code, including: From each battery branch, the battery branch whose working state is represented by the state code is an effective state is determined as the effective branch; Based on the branch charge data and rated capacity of the effective branches, the system state of charge of the battery system is determined.

[0065] Specifically, taking a commercial vehicle battery system with four parallel branches as an example, after the aforementioned state coding, the system identifies three branches as having valid operating states, while one branch is marked as having an invalid operating state due to exceeding temperature limits. When calculating the state of charge (SOC) of the entire vehicle battery system, the system only includes the three valid branches in the calculation: it obtains the branch charge data and rated capacity of each of the three valid branches, multiplies the branch charge data of each valid branch by its rated capacity, sums the results, and then divides by the sum of the rated capacities of all valid branches to obtain the capacity-weighted SOC of the system. The branch marked as invalid does not participate in the above weighted calculation (it can be excluded from the calculation directly, or its corresponding weight can be set to zero to exclude it), thereby avoiding interference from this faulty branch in the overall SOC estimation of the system.

[0066] Therefore, this embodiment of the application filters valid branches based on state codes and performs weighted fusion calculation based on the charge data of valid branches and rated capacity, so that the system charge state is determined only by the data of normally operating branches, eliminating the interference of non-valid working branches on system-level estimation and improving the estimation accuracy of system charge state.

[0067] In some embodiments, the system's state of charge (SOC) includes a target SOC and a displayed SOC. The target SOC is obtained by capacity-weighted fusion of the branch charge data of the effective branches and their rated capacity. The displayed SOC is updated based on the target SOC using an ampere-hour integral method, and the following rate is dynamically adjusted according to the difference between the displayed SOC and the target SOC, allowing the displayed SOC to smoothly approximate the target SOC. Thus, when the branch state changes, the displayed SOC achieves a smooth transition through rate control, avoiding abrupt changes and improving the driving experience and system stability.

[0068] In some embodiments, the target state of charge is dynamically updated based on the total system current and total system capacity, and can be calculated using the following formula:

[0069] in, Let be the target state of charge at time t. and This represents the total system current and total capacity obtained by weighted summation based on the effective branches. This target state of charge serves as a real-world energy reference value for internal system management, accurately reflecting the overall true remaining energy level of the effective branches.

[0070] In some embodiments, the above-described displayed state of charge is used for user-facing display. The displayed state of charge is updated based on the target state of charge using an ampere-hour integral method, and a smooth transition is achieved by following the rate. Its calculation formula is as follows:

[0071] in, Let be the displayed state of charge at time t, and Rate be the following rate of the displayed state of charge, which is dynamically adjusted based on the difference between the displayed state of charge and the target state of charge. In this way, when the branch state changes, the displayed value achieves a smooth transition through rate control, avoiding abrupt changes and improving the driving experience and system stability.

[0072] In some embodiments, determining the system state of charge of the battery system based on the branch charge data and rated capacity of the effective branches includes: The sum of the products of the branch charge data and the rated capacity of each effective branch is used as the first parameter; The sum of the rated capacities of all effective branches is used as the second parameter; The ratio between the first parameter and the second parameter is taken as the system state of charge of the battery system.

[0073] Specifically, suppose a commercial vehicle battery system currently has three active branches operating normally, with rated capacities of 100 AH, 50 AH, and 150 AH, respectively. The branch charge values ​​calculated using the aforementioned steps are 80%, 60%, and 90%, respectively. When calculating the overall system state of charge (SOC), the calculation does not simply take the arithmetic mean of the three branch charge values. Instead, it fully considers the contribution of each branch's capacity difference to the total system charge: first, the charge value of each active branch is multiplied by its rated capacity, i.e., 80% × 100, 60% × 50, and 90% × 150, and the sum of these multiplications is used as the first parameter; then, the rated capacities of the three active branches are directly added together as the second parameter; finally, the first parameter is divided by the second parameter to obtain approximately 81.7% of the system SOC. Thus, the third branch with the largest rated capacity has the highest contribution to the vehicle's energy storage capacity, and its 90% state of charge has a greater weight in the final result; while the second branch with a smaller capacity, even if its state of charge is low, has its impact on the overall system limited to its capacity ratio, thereby avoiding the situation where individual small-capacity branches abnormally lower or raise the estimated value of the overall system's state of charge.

[0074] Based on this, the embodiments of this application calculate the system state of charge by weighted averaging with rated capacity as the weight, so that the contribution of each branch to the overall system state of charge matches its physical energy storage capacity. The state changes of large-capacity branches can be more significantly reflected in the system-level results, while the local fluctuations of small-capacity branches are reasonably constrained, thereby improving the accuracy of the system state of charge in representing the true remaining capacity of the battery system.

[0075] In some embodiments, the determination of the system state of charge of the battery system based on the branch charge data and rated capacity of the effective branches is achieved through the following capacity-weighted fusion formula:

[0076] in, For the branch charge data of effective branch i, Let i be the rated capacity of the effective branch. In this way, the contribution of each branch to the overall state of charge of the system is matched with its physical energy storage capacity. The state changes of large-capacity branches can be more significantly reflected in the system-level results, improving the accuracy of the system's state of charge in representing the true remaining capacity of the battery system.

[0077] In some embodiments, the method further includes: Receive a status calibration command for at least one of the battery branches; Based on the status calibration command, the status code of the corresponding battery branch is updated to either the first code that identifies the valid working state or the second code that identifies the invalid working state. Receive a recovery command for at least one of the battery branches; Based on the recovery command, the status code of the corresponding battery branch is restored to the preset code.

[0078] Specifically, taking commercial vehicle after-sales maintenance as an example, when repair personnel inspect a vehicle using a diagnostic tool, if they discover that a second branch circuit needs to be temporarily shut down due to poor wiring contact, the personnel can send a status calibration command to the battery management system via the diagnostic tool to manually update the status code of that branch circuit to a code indicating an invalid working state (e.g., changing from "1" to "0"), temporarily excluding it from the system's state of charge calculation. After the fault is resolved, the personnel can then send a recovery command via the diagnostic tool, and the system will restore the status code of that branch circuit to the factory-preset default code (e.g., restoring it to "1"), allowing it to be included back in the system's state of charge calculation. In this way, without modifying the software program or rewriting the vehicle calibration data, the temporary adjustment and restoration of the branch circuit status can be quickly completed through command interaction.

[0079] Therefore, this application embodiment realizes flexible manual intervention and rapid rollback of the working status of battery branches by supporting the interaction of external status calibration commands and recovery commands. This facilitates the temporary elimination of abnormal branches during after-sales maintenance or fault handling, and convenient restoration after repair, thereby improving the maintainability and operation and maintenance efficiency of the battery system.

[0080] In some embodiments, the aforementioned preset code is stored in non-volatile memory (NVM) as the system's factory default configuration. The aforementioned status calibration command is sent to the battery management system via the Unified Diagnostic Service (UDS) protocol to achieve temporary calibration during after-sales maintenance or fault handling; the aforementioned recovery command is also triggered via the Unified Diagnostic Service protocol, restoring the status code of the corresponding battery branch to the preset code stored in the NVM. In this way, maintenance personnel can quickly complete the temporary troubleshooting and recovery of faulty branches without requiring recalibration of the entire vehicle, improving the system's maintainability.

[0081] Based on the same technical concept, embodiments of this application also provide a battery system state of charge determination device, referencing... Figure 2 , Figure 2 This is a schematic diagram of the structure of the battery system state-of-charge determination device provided in an embodiment of this application. Figure 2 As shown, the battery system includes multiple parallel battery branches. The state-of-charge determination device for the battery system includes at least a state coding module 201, a data acquisition module 202, and a charge calculation module 203, wherein: The status coding module 201 is used to determine the status code corresponding to each battery branch based on the operating data of each battery branch; wherein, the status code is used to identify whether the battery branch is in an effective working state. Data acquisition module 202 is used to acquire the branch charge data of each battery branch; The charge calculation module 203 is used to determine the system charge state of the battery system based on the branch charge data of each battery branch and the corresponding state code.

[0082] In some embodiments, the status coding module 201 includes: The branch status determination unit is used to determine the working status of each battery branch based on the operating data of each battery branch and the corresponding preset threshold range; wherein, the operating data includes at least one of current data, voltage data and temperature data, and the preset threshold range includes at least one of the corresponding preset current range, preset voltage range and preset temperature range. The status coding configuration unit is used to determine the status code corresponding to each battery branch based on the working status.

[0083] In some embodiments, the status coding module 201 includes: The data comparison unit is used to compare the operating data of each battery branch with the corresponding preset threshold range; The state determination unit is used to determine that the working state of the battery branch is invalid if the operating data of the battery branch exceeds the corresponding preset threshold range; otherwise, it determines that the working state of the battery branch is valid.

[0084] In some embodiments, each battery branch includes multiple cells connected in series; Data acquisition module 202 includes: Voltage data acquisition unit, used to acquire voltage data of multiple cells in each battery branch; The extreme value cell determination unit is used to determine the first cell with the highest voltage and the second cell with the lowest voltage in each battery branch based on voltage data. An extreme charge acquisition unit is used to acquire the first charge value of the first battery cell and the second charge value of the second battery cell. An extreme charge correction unit is used to correct the first charge value and the second charge value respectively based on a preset mapping table if a preset correction condition is met, so as to obtain the corresponding maximum charge value and minimum charge value. Otherwise, the first charge value is taken as the maximum charge value, and the second charge value is taken as the minimum charge value; The extreme value weight determination unit is used to determine the first weight corresponding to the maximum charge value and the second weight corresponding to the minimum charge value based on the maximum charge value, the minimum charge value, the preset maximum charge threshold, and the preset minimum charge threshold. The branch charge calculation unit is used to calculate the branch charge data of each battery branch based on the maximum charge value, the minimum charge value, the first weight, and the second weight.

[0085] In some embodiments, the data acquisition module 202 includes: An extreme voltage acquisition unit is used to acquire the first voltage of the first battery cell and the second voltage of the second battery cell. The maximum charge mapping unit is used to determine the maximum charge value based on the first voltage and a preset mapping table; The minimum charge mapping unit is used to determine the minimum charge value based on the second voltage and a preset mapping table.

[0086] In some embodiments, the charge calculation module 203 includes: The effective branch screening unit is used to identify the battery branches whose working state represented by the state code is an effective state from each battery branch as effective branches. The system charge determination unit is used to determine the system state of charge of the battery system based on the branch charge data and rated capacity of the effective branches.

[0087] In some embodiments, the charge calculation module 203 includes: The weighted numerator calculation unit is used to sum the product of the branch charge data and the rated capacity of each effective branch as the first parameter; The total capacity calculation unit is used to use the sum of the rated capacities of each effective branch as the second parameter; The weighted ratio calculation unit is used to take the ratio between the first parameter and the second parameter as the system state of charge of the battery system.

[0088] In some embodiments, the method further includes a calibration and recovery module, the module comprising: A calibration instruction receiving unit is used to receive a status calibration instruction for at least one of the battery branches in each battery branch. The status coding calibration unit is used to update the status code of the corresponding battery branch to a first code that identifies a valid working state or a second code that identifies an invalid working state based on the status calibration command. A recovery command receiving unit is used to receive a recovery command for at least one of the battery branches. The status code recovery unit is used to restore the status code of the corresponding battery branch to the preset code based on the recovery command.

[0089] It should be noted that the state of charge determination device for this battery system can be used to implement any of the above method embodiments.

[0090] Based on the same technical concept, this application also provides an electronic device, see reference. Figure 3 , Figure 3 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Figure 3 As shown, the electronic device includes a memory 301 and a processor 302. The memory 301 is used to store computer instructions; when the processor 302 executes the computer instructions, it implements any of the above-described method embodiments.

[0091] The memory 301 includes at least one type of computer-readable storage medium, including flash memory, hard disk, multimedia card, random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), magnetic disk, optical disk, etc. In some embodiments, the computer-readable storage medium may be an internal storage unit of an electronic device, such as the hard disk or memory of the electronic device. In other embodiments, the computer-readable storage medium may also be an external storage device of the electronic device, such as a plug-in hard disk, secure digital card (SD card), flash memory card, etc., equipped on the electronic device. Of course, the computer-readable storage medium may include both internal storage units and external storage devices of the electronic device. In this embodiment, the computer-readable storage medium is typically used to store the operating system and various application software installed on the electronic device, such as the program code of the battery system state-of-charge determination method in the embodiment. In addition, the computer-readable storage medium may also be used to temporarily store various types of data that have been output or will be output.

[0092] In some embodiments, processor 302 may be a central processing unit (CPU), controller, microcontroller, microprocessor, or other chip. Processor 302 is typically used to control the overall operation of the electronic device, such as performing control and processing related to data interaction or communication with other entities. In this embodiment, processor 302 is used to run program code stored in memory 301 or process data.

[0093] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0094] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A method for determining the state of charge of a battery system, characterized in that, The battery system includes multiple parallel battery branches, and the method includes: Based on the operating data of each battery branch, the status code corresponding to each battery branch is determined; wherein, the status code is used to identify whether the battery branch is in an effective working state. Obtain the branch charge data of each battery branch; Based on the branch charge data and corresponding state codes of each battery branch, the system state of charge of the battery system is determined.

2. The method according to claim 1, characterized in that, The determination of the state code corresponding to each battery branch based on the operating data of each battery branch includes: Based on the operating data of each battery branch and the corresponding preset threshold range, the operating status of each battery branch is determined; wherein, the operating data includes at least one of current data, voltage data and temperature data, and the preset threshold range includes at least one of the corresponding preset current range, preset voltage range and preset temperature range. The state code corresponding to each battery branch is determined based on the operating state.

3. The method according to claim 2, characterized in that, The process of determining the operating status of each battery branch based on its operating data and corresponding preset threshold range includes: The operating data of each battery branch is compared with the corresponding preset threshold range; If the operating data of the battery branch exceeds the corresponding preset threshold range, the working state of the battery branch is determined to be invalid; otherwise, the working state of the battery branch is determined to be valid.

4. The method according to claim 1, characterized in that, Each battery branch includes multiple cells connected in series; The acquisition of branch charge data for each battery branch includes: Obtain voltage data of multiple cells in each battery branch; Based on the voltage data, determine the first cell with the highest voltage and the second cell with the lowest voltage in each battery branch; Obtain the first charge value of the first battery cell and the second charge value of the second battery cell; If the preset correction conditions are met, the first charge value and the second charge value are corrected based on the preset mapping table to obtain the corresponding maximum charge value and minimum charge value. Otherwise, the first charge value is taken as the maximum charge value, and the second charge value is taken as the minimum charge value; Based on the maximum charge value, the minimum charge value, the preset maximum charge threshold, and the preset minimum charge threshold, a first weight corresponding to the maximum charge value and a second weight corresponding to the minimum charge value are determined; Based on the maximum charge value, the minimum charge value, the first weight, and the second weight, the branch charge data of each battery branch is calculated.

5. The method according to claim 4, characterized in that, The step of correcting the first charge value of the first battery cell and the second charge value of the second battery cell based on a preset mapping table to obtain the corresponding maximum and minimum charge values ​​includes: Obtain the first voltage of the first battery cell and the second voltage of the second battery cell; The maximum charge value is determined based on the first voltage and the preset mapping table; The minimum charge value is determined based on the second voltage and the preset mapping table.

6. The method according to claim 3, characterized in that, The determination of the system state of charge of the battery system based on the branch charge data and corresponding state codes of each battery branch includes: From each battery branch, the battery branch whose working state represented by the state code is the effective state is determined as the effective branch; Based on the branch charge data and rated capacity of the effective branches, the system state of charge of the battery system is determined.

7. The method according to claim 6, characterized in that, The determination of the system state of charge of the battery system based on the branch charge data and rated capacity of the effective branches includes: The sum of the products of the branch charge data and the rated capacity of each effective branch is used as the first parameter; The sum of the rated capacities of all effective branches is used as the second parameter; The ratio between the first parameter and the second parameter is taken as the system state of charge of the battery system.

8. The method according to claim 1, characterized in that, The method further includes: Receive a status calibration command for at least one of the battery branches; Based on the state calibration instruction, the state code of the corresponding battery branch is updated to either the first code that identifies a valid working state or the second code that identifies an invalid working state. Receive a recovery command for at least one of the battery branches; Based on the recovery command, the status code of the corresponding battery branch is restored to the preset code.

9. A device for determining the state of charge of a battery system, characterized in that, The battery system includes multiple parallel battery branches, and the device includes: The status coding module is used to determine the status code corresponding to each battery branch based on the operating data of each battery branch; wherein, the status code is used to identify whether the battery branch is in an effective working state; The data acquisition module is used to acquire the branch charge data of each battery branch; The charge calculation module is used to determine the system charge state of the battery system based on the branch charge data of each battery branch and the corresponding state code.

10. An electronic device, characterized in that, It includes a memory and a processor, the memory being used to store computer programs or instructions; when the computer programs or instructions are executed by the processor, the method of any one of claims 1-7 is implemented.

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