Charge state determination method and device, battery system, medium and product

Abstract

The invention discloses a state-of-charge determination method and device, a battery system, a medium and a product, and relates to the technical field of battery management, the method comprises the following steps: applying the state-of-charge determination method to the battery system, the battery system comprising a plurality of groups of battery cells, and obtaining open-circuit voltages of the plurality of groups of battery cells; determining a voltage comparison result and / or voltage difference data among the plurality of groups of battery cells based on the open-circuit voltage; according to the voltage comparison result and / or the voltage difference data, the interval to which the state of charge of the battery system belongs is determined, and the real-time voltage difference of the system is increased through the groups of battery cells in different states, so that the interval to which the state of charge belongs can be effectively distinguished through the voltage comparison result and / or the voltage difference data determined by the open-circuit voltage of each group of battery cells. The accuracy and the efficiency of determining the state of charge of the battery can be improved, so that the safety of the battery and the dynamic property of the whole vehicle are improved.

Description

Technical Field

[0001] The present application relates to the field of battery management technology, and in particular to a method, device, battery system, medium and product for determining a state of charge. Background Art

[0002] A battery's state of charge (SOC) refers to the ratio of the amount of energy stored in a battery at a specific moment to its rated capacity, usually expressed as a percentage. SOC is an important indicator for assessing a battery's current remaining energy and is crucial for battery management and use.

[0003] Traditional methods for determining the state of charge (SOC) mainly include the ampere-hour integration method and the dynamic OCV (Open Circuit Voltage) method, which are prone to large deviations when applied. Specifically, in the absence of a plug-in full-charge calibration scenario for most hybrid vehicles, the SOC deviation of the ampere-hour integration method will continue to accumulate. In the dynamic OCV method, during the plateau period when voltage changes are relatively small, it is difficult to effectively distinguish between different SOCs under common current formats, which can easily lead to incorrect SOC corrections, affecting the vehicle's power performance and battery safety.

[0004] Therefore, it is necessary to propose a solution to improve the accuracy of battery state of charge determination.

[0005] The above content is only used to assist in understanding the technical solution of this application and does not constitute an admission that the above content is prior art. Summary of the Invention

[0006] The main purpose of this application is to provide a method, device, battery system, medium and product for determining the state of charge, aiming to improve the accuracy of determining the battery state of charge.

[0007] To achieve the above-mentioned object, the present application provides a method for determining a state of charge. The method is applied to a battery system, wherein the battery system includes a plurality of groups of battery cells, the plurality of groups of battery cells including a first battery cell, a second battery cell, and a third battery cell, wherein the first battery cell, the second battery cell, and the third battery cell have the same specifications, the second battery cell and the first battery cell have the same calibrated capacity but a different charging capacity, and the third battery cell and the first battery cell have the same charging capacity but a different calibrated capacity. The method includes:

[0008] Obtaining the open circuit voltages of the plurality of battery cells;

[0009] Determine voltage comparison results and / or voltage difference data between the plurality of groups of battery cells based on the open circuit voltage;

[0010] The interval to which the state of charge of the battery system belongs is determined according to the voltage comparison result and / or the pressure difference data.

[0011] In one embodiment, the several groups of battery cells include a first battery cell, a second battery cell and a third battery cell, wherein the specifications of the first battery cell, the second battery cell and the third battery cell are the same, the second battery cell has the same rated capacity as the first battery cell and a different charging capacity, and the third battery cell has the same charging capacity as the first battery cell and a different rated capacity.

[0012] In one embodiment, the charge capacity of the second battery cell is lower than the charge capacity of the first battery cell, and the rated capacity of the third battery cell is lower than the rated capacity of the first battery cell. The step of determining the voltage comparison results and / or voltage difference data between the plurality of battery cell groups based on the open circuit voltage includes:

[0013] Comparing the open circuit voltages of the first battery cell, the second battery cell, and the third battery cell to obtain a voltage comparison result of the first battery cell, the second battery cell, and the third battery cell;

[0014] If the open circuit voltage of the first battery cell is equal to the open circuit voltage of the third battery cell in the voltage comparison result, the difference between the open circuit voltages of the first battery cell and / or the third battery cell and the second battery cell is calculated to obtain the voltage difference data between the first battery cell and / or the third battery cell and the second battery cell.

[0015] In one embodiment, the interval to which the state of charge belongs includes several intervals, and different voltage comparison results and / or voltage difference data correspond to different intervals to which the state of charge belongs.

[0016] In one embodiment, the plurality of intervals include a first interval, a second interval, a third interval, and a fourth interval, a lower limit value of the first interval is greater than or equal to an upper limit value of the second interval, a lower limit value of the second interval is greater than or equal to an upper limit value of the third interval, and a lower limit value of the third interval is greater than or equal to an upper limit value of the fourth interval, and the step of determining the interval to which the state of charge of the battery system belongs based on the voltage comparison result and / or the pressure difference data includes:

[0017] If the open circuit voltage of the second battery cell is greater than the open circuit voltage of the third battery cell in the voltage comparison result, determining that the state of charge is in the fourth interval;

[0018] If, in the voltage comparison result, the open circuit voltage of the first battery cell is greater than the open circuit voltage of the third battery cell, and the open circuit voltage of the third battery cell is greater than the open circuit voltage of the second battery cell, determining that the state of charge is in the third range;

[0019] When the voltage difference data between the first battery cell and / or the third battery cell and the second battery cell is greater than a preset voltage difference threshold, determining that the state of charge is in the second range;

[0020] When the voltage difference data between the first battery cell and / or the third battery cell and the second battery cell is less than or equal to a preset voltage difference threshold, it is determined that the state of charge is in the first range.

[0021] In one embodiment, when the voltage difference data between the first battery cell and / or the third battery cell and the second battery cell is greater than a preset voltage difference threshold, before the step of determining that the state of charge is in the second range, the step further includes:

[0022] When the battery system enters a current stable operating condition, recording the open circuit voltages of the first battery cell, the second battery cell, and the third battery cell at each moment within a first preset time period;

[0023] Calculating the difference in open circuit voltage between the first battery cell and / or the third battery cell and the second battery cell at each time to obtain voltage difference recording data;

[0024] The pressure difference recording data is smoothed to obtain a pressure difference change curve, and the preset pressure difference threshold is determined according to the pressure difference change curve.

[0025] In addition, to achieve the above-mentioned purpose, the present application also proposes a state of charge determination device, which is applied to a battery system, wherein the battery system includes several groups of battery cells, and the several groups of battery cells include a first battery cell, a second battery cell, and a third battery cell, wherein the first battery cell, the second battery cell, and the third battery cell have the same specifications, the second battery cell has the same calibrated capacity as the first battery cell and a different charging capacity, and the third battery cell has the same charging capacity as the first battery cell and a different calibrated capacity. The device includes:

[0026] An acquisition module, configured to acquire the open circuit voltages of the plurality of battery cells;

[0027] a comparison module, configured to determine voltage comparison results and / or voltage difference data between the plurality of groups of battery cells based on the open circuit voltage;

[0028] A determination module is used to determine the interval to which the state of charge of the battery system belongs based on the voltage comparison result and / or the pressure difference data.

[0029] In addition, to achieve the above-mentioned purpose, the present application also proposes a state of charge determination device, which includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program is configured to implement the steps of the state of charge determination method as described above.

[0030] In addition, to achieve the above-mentioned purpose, the present application also proposes a battery system, which includes several groups of battery cells, wherein the several groups of battery cells include a first battery cell, a second battery cell and a third battery cell, the specifications of the first battery cell, the second battery cell and the third battery cell are the same, the second battery cell has the same rated capacity as the first battery cell and a different charging capacity, and the third battery cell has the same charging capacity as the first battery cell and a different rated capacity.

[0031] In addition, to achieve the above-mentioned purpose, the present application also proposes a storage medium, which is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by the processor, the steps of the charge state determination method described above are implemented.

[0032] In addition, to achieve the above-mentioned purpose, the present application also provides a computer program product, which includes a computer program. When the computer program is executed by a processor, the steps of the charge state determination method as described above are implemented.

[0033] One or more technical solutions proposed in this application have at least the following technical effects:

[0034] A state of charge determination method is applied to a battery system, wherein the battery system includes several groups of battery cells, and the several groups of battery cells include a first battery cell, a second battery cell, and a third battery cell, wherein the first battery cell, the second battery cell, and the third battery cell have the same specifications, the second battery cell has the same calibrated capacity as the first battery cell, but a different charging capacity, and the third battery cell has the same charging capacity as the first battery cell, but a different calibrated capacity. The open circuit voltage of the several groups of battery cells is obtained; voltage comparison results and / or pressure difference data between the several groups of battery cells are determined based on the open circuit voltage; the range to which the state of charge of the battery system belongs is determined according to the voltage comparison results and / or pressure difference data, and the real-time pressure difference of the system is increased by groups of battery cells in different states. The voltage comparison results and / or pressure difference data determined by the open circuit voltage of each group of battery cells can effectively distinguish the range to which the state of charge belongs, thereby improving the accuracy and efficiency of determining the battery state of charge, thereby contributing to improving battery safety and vehicle power. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0036] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0037] Figure 1 This is a schematic diagram of the original SOC-OCV data of a battery cell in the prior art;

[0038] Figure 2 The SOC-OCV curve of the battery cell in the prior art is intended to be fitted;

[0039] Figure 3 This is a flow chart of the first embodiment of the method for determining the state of charge of the present application;

[0040] Figure 4 Schematic diagram of the capacity and voltage of each battery cell according to an embodiment of the present application;

[0041] Figure 5 This is a flow chart of a second embodiment of the method for determining the state of charge of the present application;

[0042] Figure 6 Schematic diagram of OCV data curves corresponding to different SOC stages according to an embodiment of the present application;

[0043] Figure 7 This is a flow chart of a third embodiment of the method for determining the state of charge of the present application;

[0044] Figure 8 A schematic diagram of a judgment logic according to an embodiment of the present application is shown;

[0045] Figure 9 This is a schematic diagram of the module structure of the device for determining the state of charge according to an embodiment of the present application;

[0046] Figure 10 Schematic diagram of the device structure of the hardware operating environment involved in the charge state determination method in the embodiment of the present application.

[0047] The purpose, features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0048] It should be understood that the specific embodiments described herein are merely used to explain the technical solutions of the present application and are not intended to limit the present application.

[0049] In order to better understand the technical solution of the present application, a detailed description will be given below in conjunction with the accompanying drawings and specific implementation methods.

[0050] The main solution of the embodiment of the present application is: applying the state of charge determination method to a battery system, wherein the battery system includes several groups of battery cells, and the several groups of battery cells include a first battery cell, a second battery cell and a third battery cell, wherein the first battery cell, the second battery cell and the third battery cell have the same specifications, the second battery cell has the same calibrated capacity as the first battery cell and a different charging capacity, and the third battery cell has the same charging capacity as the first battery cell and a different calibrated capacity, by obtaining the open circuit voltage of the several groups of battery cells; determining the voltage comparison results and / or pressure difference data between the several groups of battery cells based on the open circuit voltage; determining the range to which the state of charge of the battery system belongs according to the voltage comparison results and / or pressure difference data, increasing the real-time pressure difference of the system by each group of battery cells in different states, and then effectively distinguishing the range to which the state of charge belongs by the voltage comparison results and / or pressure difference data determined by the open circuit voltage of each group of battery cells, which can improve the accuracy and efficiency of battery state of charge determination, thereby helping to improve battery safety and vehicle power.

[0051] In this embodiment, for ease of description, the state of charge determination device is used as the execution subject for explanation below.

[0052] Technical terms involved in the embodiments of this application:

[0053] SOC: State of Charge, remaining power state, also known as state of charge;

[0054] OCV: Open Circuit Voltage.

[0055] For hybrid vehicles, the various subsystems of the vehicle (such as the engine management system, motor control system, braking system, etc.) need to work closely together. SOC determination, as key information of the battery management system, will be transmitted to the vehicle controller in real time, integrated and shared with information from other systems, to achieve intelligent control and coordinated operation of the entire vehicle. For example, the vehicle controller can make comprehensive decisions on the vehicle's operating mode and power output strategy based on SOC information as well as information such as vehicle speed and load, thereby improving the vehicle's overall performance and efficiency. Therefore, SOC determination plays an important role in vehicles equipped with hybrid battery systems. In the embodiments of this application, a lithium iron phosphate hybrid battery system is used as an example for illustration.

[0056] For lithium iron phosphate hybrid battery systems, the plateau period covers a large SOC range. However, traditional SOC determination methods are prone to large calculation errors in hybrid applications of lithium iron phosphate chemistry systems:

[0057] (1) Ampere-hour integration method: Many hybrid models lack the scenario of plug-in full charge calibration, and SOC deviation continues to accumulate;

[0058] (2) Dynamic OCV method: During the plateau period, the SOC of common current formats is different and cannot be effectively distinguished using dynamic OCV, which can easily lead to incorrect SOC correction.

[0059] Reference Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of the original SOC-OCV data of the battery cell in the prior art. Figure 2 This is the SOC-OCV fitting curve of the battery cell in the prior art, as shown in the figure. Figure 1 A smooth fitting curve can be obtained by fitting the original data in . Before and after fitting, it can be seen that the OCV changes slightly in the SOC range of 20% to 95%, that is, the OCVs corresponding to the SOCs of 20% to 95% are relatively close. Therefore, it is difficult to determine the SOC by OCV in the SOC range of 20% to 95%, which can easily lead to a low accuracy rate in the determined SOC.

[0060] In the existing technology, there is a solution to determine the SOC by inserting a ternary module in series into the iron-lithium system. The ternary chemical system makes it easy to perform dynamic OCV method judgment and improve the system SOC accuracy. However, the cost difference between the ternary module and the iron-lithium module used in this solution is large, which can easily lead to an increase in overall cost. In order to improve volume utilization, the CTP3.0 grouping method requires that the battery cells are exactly the same size to support this solution, resulting in low applicability of this method.

[0061] The existing technology also includes a solution of connecting multiple sodium-ion batteries in series in the iron-lithium system to determine the SOC. Through the sodium-ion chemical system, it is easy to use the dynamic OCV method to determine the advantage, improve the system SOC accuracy at a low cost, and avoid the risk of edge batteries being affected by low temperatures. However, this solution is not easy to spread the cost because the number of sodium-ion batteries used is small (and the market size is small), the order volume of the battery cell end is relatively limited, and some companies have relatively low investment in sodium-ion battery research and development, so the adaptability of the solution is relatively low.

[0062] In summary, the solutions in the prior art have problems such as increasing the difficulty of battery development or production costs. A solution is proposed in the embodiment of the present application. When the battery cells are grouped, two additional states of the same type of battery cells are added to increase the real-time pressure difference of the battery system. The pressure difference of the system under a certain format is used to confirm the SOC range of the current battery system.

[0063] It should be noted that the execution subject of this embodiment may be a computing service device with data processing, network communication, and program execution functions, such as a tablet computer, personal computer, mobile phone, etc., or an electronic device capable of implementing the above functions, a state of charge determination device, etc. The following uses the state of charge determination device as an example to illustrate this embodiment and the following embodiments.

[0064] Based on this, an embodiment of the present application provides a method for determining the state of charge, which is applied to a battery system, wherein the battery system includes a plurality of battery cells. Figure 3 , Figure 3 This is a flow chart of the first embodiment of the method for determining the state of charge of the present application.

[0065] In this embodiment, the state of charge determination method includes steps S10 to S40:

[0066] Step S10, obtaining the open circuit voltages of the plurality of battery cells;

[0067] For example, a battery cell is the basic component unit of a battery, and several groups of battery cells are combined to form a battery pack. The battery system in the embodiment of the present application includes battery cells in three different states, wherein the number of battery cells in each state can be one or more. The embodiment of the present application is described as an example in which there is only one battery cell in each state.

[0068] Illustratively, the battery system in the embodiment of the present application includes several groups of battery cells including a first battery cell, a second battery cell and a third battery cell, wherein the specifications of the first battery cell, the second battery cell and the third battery cell are the same, the second battery cell has the same rated capacity as the first battery cell and a different charging capacity, and the third battery cell has the same charging capacity as the first battery cell and a different rated capacity.

[0069] Exemplarily, the charging capacity of the second battery cell is lower than the charging capacity of the first battery cell, and the rated capacity of the third battery cell is lower than the rated capacity of the first battery cell.

[0070] Exemplarily, the first battery cell is a conventional battery cell, and the second battery cell and the third battery cell are two states of conventional battery cells. For example, the second battery cell has the same rated capacity and a lower OCV as the first battery cell, and the third battery cell has a lower rated capacity and the same OCV than the first battery cell. In other words, the second battery cell has the same rated capacity as the first battery cell but a less charged capacity, and the third battery cell is a low-capacity battery cell with the same charged capacity as the first battery cell.

[0071] Reference Figure 4 , Figure 4 Schematic diagram of the capacity and voltage of each battery cell according to an embodiment of the present application, as shown in FIG. Figure 4 As shown, from Figure 4 The cell capacity and voltage on the left show that when the cells are assembled into the battery system, the differences in capacity and voltage of each cell are small. Figure 4It can be seen from the cell capacity and voltage conditions on the right that when the battery system is fully charged for the first time, the capacity and voltage of each cell are greatly increased compared to the state when the cells are grouped into the battery system, and the difference in capacity and voltage of each cell is significantly increased. This application can increase the real-time pressure difference of the system by adding two additional states of the same type of cell when the cells are grouped. The pressure difference of the system under a certain configuration can be used to determine the current SOC range of the battery system.

[0072] For example, the potential difference between the two poles of the battery cell in the open circuit state (i.e. when no current flows) is the open circuit voltage (OCV). The open circuit voltage is the voltage performance when the electrochemical reaction inside the battery reaches a state of equilibrium. Different charge states correspond to different open circuit voltage values.

[0073] Illustratively, after the open circuit voltage of each battery cell is obtained, the voltage comparison result and / or the voltage difference data may be determined based on the open circuit voltage of each battery cell.

[0074] Step S20, determining voltage comparison results and / or voltage difference data between the plurality of groups of battery cells based on the open circuit voltage;

[0075] For example, when the battery system is in different state of charge ranges, the voltage comparison results and / or voltage difference data between the battery cells thereof may show certain regularities, and these regularities provide a basis for determining the state of charge range.

[0076] For example, in the embodiment of the present application, the OCV corresponding to different SOCs is determined based on a large amount of pre-collected data, and the magnitude relationship or voltage difference range between the open circuit voltages corresponding to each battery cell when the SOC is in different intervals is further clarified.

[0077] For example, the voltage comparison results include information such as the magnitude relationship or ranking of the voltages between cells, which can be used to easily and efficiently determine the SOC range. The differential voltage data reflects the difference in open-circuit voltage between cells, especially near key points that distinguish different SOC ranges. This differential voltage data can provide a more accurate basis for judgment.

[0078] Exemplarily, the step of determining the voltage comparison results and / or voltage difference data between the plurality of groups of battery cells based on the open circuit voltage includes:

[0079] Comparing the open circuit voltages of the first battery cell, the second battery cell, and the third battery cell to obtain a voltage comparison result of the first battery cell, the second battery cell, and the third battery cell;

[0080] If the open circuit voltage of the first battery cell is equal to the open circuit voltage of the third battery cell in the voltage comparison result, the difference between the open circuit voltages of the first battery cell and / or the third battery cell and the second battery cell is calculated to obtain the voltage difference data between the first battery cell and / or the third battery cell and the second battery cell.

[0081] Exemplarily, in the embodiment of the present application, the intervals to which the state of charge belongs include a first interval, a second interval, a third interval, and a fourth interval. The lower limit value of the first interval is greater than or equal to the upper limit value of the second interval, the lower limit value of the second interval is greater than or equal to the upper limit value of the third interval, and the lower limit value of the third interval is greater than or equal to the upper limit value of the fourth interval. For example: the first interval is (100%-75%), the second interval is (75%-40%), the third interval is (40%-25%), and the fourth interval is (25%-0%). In other embodiments, the upper limit value and / or lower limit value of each interval can be selected according to actual needs. When the state of charge is in the third interval or the fourth interval, the voltage comparison result can directly distinguish the interval to which the state of charge belongs, and the pressure difference data can clearly distinguish the interval to which the state of charge belongs when the state of charge is in the first interval, the second interval, the third interval and the fourth interval. It has a wider scope of application, but has certain requirements for computing power. In order to maximize the advantages of the two methods, in the embodiment of the present application, the voltage comparison result is preferentially used to distinguish the interval to which the state of charge belongs. When the voltage comparison result is difficult to distinguish, the pressure difference data is further used for interval judgment, which can achieve accurate judgment of the SOC in all stages.

[0082] Exemplarily, when the difference between the open circuit voltage of the first battery cell and the open circuit voltage of the third battery cell is within a preset threshold range, that is, the open circuit voltage of the first battery cell is approximately the same as the open circuit voltage of the third battery cell, it can be determined that the open circuit voltage of the first battery cell is equal to the open circuit voltage of the third battery cell. At this time, it is difficult to directly distinguish the interval of the state of charge through the voltage comparison result, and it is necessary to make a judgment by calculating the pressure difference data. Since the open circuit voltage of the first battery cell is equal to the open circuit voltage of the third battery cell, the difference between the open circuit voltage of the first battery cell and the open circuit voltage of the second battery cell can be calculated, and / or the difference between the open circuit voltage of the third battery cell and the open circuit voltage of the second battery cell can be calculated to obtain the pressure difference data of the first battery cell and / or the third battery cell and the second battery cell, and then the interval of the state of charge of the battery system can be judged according to the pressure difference data of the first battery cell and / or the third battery cell and the second battery cell.

[0083] For example, after determining the voltage comparison result and / or the pressure difference data based on the open circuit voltage of each battery cell, the interval to which the state of charge belongs can be determined according to the voltage comparison result and / or the pressure difference data.

[0084] Step S30 : determining the interval to which the state of charge of the battery system belongs according to the voltage comparison result and / or the pressure difference data.

[0085] Exemplarily, the interval to which the state of charge belongs is the range of the remaining power of the battery system, which is usually expressed as a percentage. The interval to which the state of charge belongs includes several intervals. Different voltage comparison results and / or pressure difference data correspond to different intervals to which the state of charge belongs. In the embodiment of the present application, the first interval (100%-75%), the second interval (75%-40%), the third interval (40%-25%) and the fourth interval (25%-0%) are used as examples for illustration. In other embodiments, the intervals can also be divided according to actual needs. The embodiment of the present application does not constitute a specific limitation on the number of intervals.

[0086] For example, in a battery system, a mapping relationship between voltage comparison results, differential pressure data, and state-of-charge intervals is pre-established based on battery characteristic data (such as an OCV-SOC curve). Then, after obtaining the voltage comparison results and differential pressure data, the battery pack's current state-of-charge interval is quickly determined by searching the mapping relationship or using a preset judgment algorithm. The result is then stored or displayed for easy access by the user and the battery management system.

[0087] For example, a detailed mapping table is pre-established based on battery characteristic test data. This mapping table contains the SOC intervals corresponding to various possible voltage comparison results and differential pressure data. In actual applications, the corresponding SOC interval is searched in the mapping table based on the obtained voltage comparison results and differential pressure data. This method is simple and direct, with fast judgment speed, but it requires the establishment of an accurate and comprehensive mapping table and is sensitive to changes in battery characteristics.

[0088] For example, a mathematical model of the battery is established, using the voltage comparison results and differential pressure data as input variables, and the model is used to calculate the state of charge range. This method can dynamically adjust according to the real-time status of the battery and is highly adaptable, but it requires high accuracy and complexity of the model and is relatively computationally intensive.

[0089] For example, a machine learning algorithm is used to train a large amount of battery data (including voltage comparison results, differential pressure data, and corresponding state-of-charge intervals) to establish an intelligent judgment model. In actual application, the acquired voltage comparison results and differential pressure data are input into the trained model to obtain a prediction result for the state-of-charge interval. This method can automatically learn the characteristics and patterns of batteries with high accuracy and adaptability, but it requires a large amount of data and computing resources during the model training phase.

[0090] For example, in practical applications, an appropriate implementation or combination of multiple approaches can be selected based on the battery type, usage scenario, and system requirements. For example, for simple battery systems with high real-time requirements, a table lookup method can be used; for complex battery systems requiring high-precision judgment, a combination of mathematical modeling and machine learning methods can be used. Initial calculations are performed using a mathematical model, followed by correction and optimization using a machine learning model. This allows for accurate and rapid judgment of the state of charge range, improving the performance and reliability of the entire battery management system.

[0091] For example, based on the SOC range, the vehicle control system can rationally allocate power output between the engine and the electric motor. For example, when the SOC is high, the electric motor can be relied upon more, leveraging its high torque and fast response, reducing the burden on the engine and improving fuel economy. When the SOC is low, the engine can be used to drive the vehicle, while the generator charges the battery to ensure continuous and stable vehicle power. During braking, SOC determination helps determine the energy recovery strength of the regenerative braking system. If the SOC is low, the energy recovery strength can be increased to convert more braking energy into stored electrical energy. Conversely, if the SOC is close to full charge, the energy recovery strength can be appropriately reduced to avoid overcharging and improve energy recovery efficiency. Based on SOC determination, the vehicle's energy management system can rationally allocate electrical energy. For example, when the SOC is high, the vehicle can be allowed to operate at a higher power level to meet its power needs. When the SOC is low, the system can automatically switch to energy-saving mode, limiting the vehicle's power output, optimizing energy efficiency, and maximizing the vehicle's range. Accurate SOC determination can provide reliable range information for electric vehicles. The vehicle can estimate the mileage that can be supported by the remaining power based on the current SOC, historical driving data, real-time operating conditions and other factors.

[0092] This embodiment adopts the above scheme, specifically by applying the state of charge determination method to a battery system, wherein the battery system includes several groups of battery cells, and the several groups of battery cells include a first battery cell, a second battery cell, and a third battery cell, wherein the first battery cell, the second battery cell, and the third battery cell have the same specifications, the second battery cell and the first battery cell have the same calibrated capacity and a different charging capacity, and the third battery cell and the first battery cell have the same charging capacity and a different calibrated capacity. By obtaining the open circuit voltage of the several groups of battery cells; determining the voltage comparison results and / or pressure difference data between the several groups of battery cells based on the open circuit voltage; determining the range to which the state of charge of the battery system belongs according to the voltage comparison results and / or pressure difference data, the real-time pressure difference of the system is increased by each group of battery cells in different states, and then the voltage comparison results and / or pressure difference data determined by the open circuit voltage of each group of battery cells can effectively distinguish the range to which the state of charge belongs, which can improve the accuracy and efficiency of battery state of charge determination, thereby helping to improve battery safety and vehicle power.

[0093] Based on the first embodiment of the present application, a second embodiment of the present application is proposed. In the second embodiment of the present application, the same or similar contents as those in the above-mentioned embodiment 1 can be referred to the above introduction and will not be repeated later.

[0094] On this basis, please refer to Figure 5 , the method further includes steps S01 to S03:

[0095] Step S01: When the battery system enters a current stable operating condition, recording the corresponding open circuit voltages of the first battery cell, the second battery cell, and the third battery cell at each moment within a first preset time period;

[0096] Step S02: calculating the difference in open circuit voltage between the first battery cell and / or the third battery cell and the second battery cell at each time, to obtain voltage difference recording data;

[0097] Step S03: Smoothing the pressure difference recording data to obtain a pressure difference change curve, and determining the preset pressure difference threshold according to the pressure difference change curve.

[0098] For example, during the charging and discharging process of the battery system, when the current remains relatively stable, the voltage of the battery cell is less affected by current fluctuations and can more accurately reflect its open circuit voltage. In the embodiments of the present application, such operating conditions are referred to as current stable operating conditions.

[0099] Exemplarily, when the battery system is in a current stable operating condition, the vehicle is mainly in a low-power scenario or a steady-speed driving scenario. For example, low-power scenarios include when the vehicle is waiting for a red light (or other short stops), when only the PTC is working, when only the air conditioner is working, or when only the low-voltage electrical system is working. After a certain period of time (for example, after 15 seconds), the relaxation portion of the voltage is almost gone, and the change trend of the corresponding OCV value is close. In such scenarios (low-power scenarios such as only the PTC is working, only the air conditioner is working, or only the low-voltage electrical system is working), the current fluctuation deviation is <±8%. After 10 seconds, the system voltage value accumulated for 10 seconds is recorded, smoothed by the averaging method, and stored in the EPROM. For another example, a steady-speed driving scenario includes a national highway or expressway scenario. Under a certain slope range, when the accelerator pedal is at 0%, the battery will have a predetermined operating condition (0 current or discharge, switching to short-term charging). The system pressure difference within a certain time range (for example, 4 to 8 seconds) is recorded, smoothed by the averaging method, and stored in the EPROM.

[0100] Reference Figure 6 , Figure 6 Schematic diagram of OCV data curve corresponding to different SOC stages according to an embodiment of the present application, as shown in FIG. Figure 6 As shown, in the embodiment of the present application, the first battery cell is marked as A, the second battery cell is marked as B, and the third battery cell is marked as C. It can be seen from the OCV data curves corresponding to each battery cell at different SOC stages that:

[0101] The first interval (stage ①): 100% to 75% SOC, dynamic voltage: C≈A>B;

[0102] Second interval (stage ②): 75% to 40% SOC, dynamic voltage: C≈A>B;

[0103] The third interval (stage ③): 40% to 25% SOC, dynamic voltage: A>C>B;

[0104] The fourth interval (stage ④): 25% to 0% SOC, dynamic voltage: A>B>C.

[0105] For example, the voltage comparison results between B and C can be used to directly determine whether the SOC is in the fourth range. Furthermore, the curve shows that within the first and second ranges, the open-circuit voltages of A and C are similar, resulting in a very small pressure difference, while the pressure difference between B and A or C is larger. Furthermore, the pressure difference between B and A or C in the first range is smaller than the pressure difference between B and A or C in the second range. Therefore, the pressure difference at the boundary between the first and second ranges can be used as the pressure difference threshold for distinguishing the first and second ranges, i.e., the preset pressure difference threshold. Furthermore, the pressure difference at the boundary between the second and third ranges can be used as the pressure difference threshold for distinguishing the second and third ranges. The values ​​recorded in the EPROM can be used to form one or two numerical ranges, thereby distinguishing the SOC ranges.

[0106] For example, smoothing the recorded differential pressure data can remove random noise and short-term fluctuations, allowing the data to more accurately reflect the long-term trend of the differential pressure between cells. The shape and characteristics of the differential pressure curve are closely related to the battery system's state of charge. By analyzing the curve, an appropriate preset differential pressure threshold can be determined.

[0107] For example, within the data processing module of the battery management system, a suitable smoothing algorithm is used to process the recorded differential pressure data. Common smoothing algorithms include moving average and exponential smoothing. A differential pressure curve is plotted based on the processed data, and a preset differential pressure threshold is determined based on the battery's characteristic data and historical experience. This threshold is used for subsequent battery state of charge assessment and management strategy development.

[0108] This embodiment adopts the above scheme, specifically by recording the open circuit voltages of the first battery cell, the second battery cell and the third battery cell at each moment within a first preset time period when the battery system enters a current stable operating condition; calculating the difference in open circuit voltages of the first battery cell and / or the third battery cell and the second battery cell at each moment to obtain pressure difference recording data; smoothing the pressure difference recording data to obtain a pressure difference change curve, and determining the preset pressure difference threshold value based on the pressure difference change curve. By recording the open circuit voltages of the battery cells under current stable operating conditions, calculating the pressure difference data and smoothing the data, the pressure difference changes between the battery cells can be accurately analyzed, providing a reliable basis for judging the state of charge of the battery system and improving the accuracy of the charge state judgment.

[0109] Based on any of the above embodiments of this application, a third embodiment of this application is proposed. In the third embodiment of this application, the same or similar contents as any of the above embodiments can be referred to the above introduction and will not be described in detail later. Figure 7 , step S30 includes steps S301 to S304:

[0110] Step S301: if the open circuit voltage of the second battery cell is greater than the open circuit voltage of the third battery cell in the voltage comparison result, determining that the state of charge is in the fourth interval;

[0111] Step S302: if, in the voltage comparison result, the open circuit voltage of the first battery cell is greater than the open circuit voltage of the third battery cell, and the open circuit voltage of the third battery cell is greater than the open circuit voltage of the second battery cell, determining that the state of charge is in the third range;

[0112] Step S303: when the voltage difference data between the first battery cell and / or the third battery cell and the second battery cell is greater than a preset voltage difference threshold, determining that the state of charge is in the second range;

[0113] Step S304: when the voltage difference data between the first battery cell and / or the third battery cell and the second battery cell is less than or equal to a preset voltage difference threshold, determining that the state of charge is in the first range.

[0114] Reference Figure 8 , Figure 8 This is a schematic diagram of the judgment logic according to an embodiment of the present application, as shown in FIG. Figure 8 As shown, there is a corresponding relationship between the open-circuit voltage and the state of charge of different battery cells. When the state of charge is in the third interval or the fourth interval, the voltage comparison result can directly distinguish the interval to which the state of charge belongs, and the pressure difference data can clearly distinguish the interval to which the state of charge belongs when the state of charge is in the first interval, the second interval, the third interval and the fourth interval. It has a wider scope of application, but has certain requirements for computing power. In order to maximize the advantages of the two methods, in the embodiment of the present application, the voltage comparison result is preferably used to distinguish the interval to which the state of charge belongs. When the voltage comparison result is difficult to distinguish, the pressure difference data is further used for interval judgment, which can achieve accurate judgment of the SOC in all stages.

[0115] For example, when the open-circuit voltage of the second cell is greater than that of the third cell, it indicates that the battery pack's overall state of charge has dropped to a lower level. The battery management system pre-sets logic rules for comparing the open-circuit voltages of each cell. When the open-circuit voltage of the second cell is greater than that of the third cell, the battery pack's state of charge can be directly determined to be in the fourth range.

[0116] For example, based on the correspondence between the open-circuit voltage and state of charge of each battery cell, when the open-circuit voltage of the first battery cell is greater than that of the third battery cell, and the open-circuit voltage of the third battery cell is greater than that of the second battery cell, it indicates that the overall state of charge of the battery pack is at a medium to low level. This is because the open-circuit voltage of the battery cell shows a certain trend of change as the state of charge decreases. The comparison logic and sequence of the open-circuit voltage of each battery cell are pre-set in the battery management system. When the condition of first battery cell > third battery cell > second battery cell is met, the state of charge is determined to be in the third range.

[0117] Illustratively, according to the pressure difference threshold pre-set in the battery management system in the aforementioned embodiment, the first interval and the second interval can be effectively distinguished. When the difference in open circuit voltage between the first battery cell and / or the third battery cell and the second battery cell is greater than the preset pressure difference threshold, the state of charge is determined to be in the second interval. When the difference in open circuit voltage between the first battery cell and / or the third battery cell and the second battery cell is less than or equal to the preset pressure difference threshold, the state of charge is determined to be in the first interval.

[0118] Through the above scheme, this embodiment specifically determines that the state of charge is in the fourth interval when the open circuit voltage of the second battery cell is greater than the open circuit voltage of the third battery cell in the voltage comparison result; determines that the state of charge is in the third interval when the open circuit voltage of the first battery cell is greater than the open circuit voltage of the third battery cell and the open circuit voltage of the third battery cell is greater than the open circuit voltage of the second battery cell in the voltage comparison result; determines that the state of charge is in the second interval when the voltage difference data between the first battery cell and / or the third battery cell and the second battery cell is greater than a preset pressure difference threshold; determines that the state of charge is in the first interval when the pressure difference data between the first battery cell and / or the third battery cell and the second battery cell is less than or equal to a preset pressure difference threshold. Through multi-dimensional judgment logic, the voltage comparison results and pressure difference data between the battery cells are comprehensively considered to accurately divide the battery state of charge into different intervals, thereby providing support for strategy adjustment of the battery management system and optimizing battery usage efficiency.

[0119] It should be noted that the above examples are only used to understand the present application and do not constitute a limitation on the method for determining the state of charge of the present application. More simple transformations based on this technical concept are all within the scope of protection of the present application.

[0120] This application also provides a device for determining the state of charge, please refer to Figure 9 The device is applied to a battery system, the battery system includes a plurality of battery cells, and the state of charge determination device includes:

[0121] An acquisition module 10 is used to obtain the open circuit voltages of the plurality of battery cells;

[0122] a comparison module 20, configured to determine voltage comparison results and / or voltage difference data between the plurality of groups of battery cells based on the open circuit voltage;

[0123] The determination module 30 is configured to determine the interval to which the state of charge of the battery system belongs based on the voltage comparison result and / or the pressure difference data.

[0124] The state-of-charge determination device provided in this application utilizes the state-of-charge determination method of the aforementioned embodiment to address the technical issues surrounding state-of-charge determination. Compared to the prior art, the state-of-charge determination device provided in this application achieves the same beneficial effects as the state-of-charge determination method of the aforementioned embodiment. Other technical features of the state-of-charge determination device are the same as those disclosed in the aforementioned embodiment and are not further detailed here.

[0125] The present application provides a state of charge determination device, which includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the state of charge determination method in the above-mentioned embodiment one.

[0126] Reference below Figure 10 , which shows a schematic diagram of the structure of a state-of-charge determination device suitable for implementing embodiments of the present application. The state-of-charge determination device in embodiments of the present application may include, but is not limited to, mobile terminals such as mobile phones, laptop computers, digital broadcast receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Descriptions), PMPs (Portable Media Players), and in-vehicle terminals (e.g., in-vehicle navigation terminals), as well as fixed terminals such as digital TVs and desktop computers. Figure 10 The state of charge determination device shown is merely an example and should not limit the functions and scope of use of the embodiments of the present application.

[0127] like Figure 10As shown, the SOC determination device may include a processing device 1001 (e.g., a central processing unit, a graphics processing unit, etc.), which can perform various appropriate actions and processes based on programs stored in a read-only memory 1002 or programs loaded from a storage device 1003 into a random access memory 1004. The random access memory 1004 also stores various programs and data required for the SOC determination device to operate. The processing device 1001, the read-only memory 1002, and the random access memory 1004 are interconnected via a bus 1005. An input / output interface 1006 is also connected to the bus. Typically, the following systems may be connected to the input / output interface 1006: an input device 1007 including, for example, a touchscreen, touchpad, keyboard, mouse, image sensor, microphone, accelerometer, gyroscope, etc.; an output device 1008 including, for example, a liquid crystal display (LCD), speaker, vibrator, etc.; a storage device 1003 including, for example, a magnetic tape, hard disk, etc.; and a communication device 1009. Communication device 1009 may allow the SOC determination device to communicate with other devices wirelessly or wired to exchange data. While the figures illustrate a SOC determination device with various systems, it should be understood that implementation or inclusion of all of the illustrated systems is not required. More or fewer systems may alternatively be implemented or included.

[0128] In particular, according to the embodiments disclosed in the present application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, the embodiments disclosed in the present application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program comprising program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network via a communication device, or installed from a storage device 1003, or installed from a read-only memory 1002. When the computer program is executed by the processing device 1001, the above-mentioned functions defined in the method of the embodiment disclosed in the present application are performed.

[0129] The state-of-charge determination device provided in this application utilizes the state-of-charge determination method of the aforementioned embodiment to address the technical issues surrounding state-of-charge determination. Compared to the prior art, the state-of-charge determination device provided in this application achieves the same beneficial effects as the state-of-charge determination method of the aforementioned embodiment. Other technical features of the state-of-charge determination device are the same as those disclosed in the aforementioned embodiment and are not further detailed here.

[0130] It should be understood that the various parts disclosed in this application can be implemented using hardware, software, firmware, or a combination thereof. In the description of the above embodiments, specific features, structures, materials, or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0131] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

[0132] The present application provides a computer-readable storage medium having computer-readable program instructions (ie, a computer program) stored thereon, the computer-readable program instructions being used to execute the state of charge determination method in the above-mentioned embodiment.

[0133] The computer-readable storage medium provided in this application may be, for example, a USB flash drive, but is not limited to electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems or devices, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In this embodiment, the computer-readable storage medium may be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system or device. The program code contained on the computer-readable storage medium may be transmitted using any appropriate medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination thereof.

[0134] The computer-readable storage medium may be included in the state of charge determination device, or may exist independently without being incorporated into the state of charge determination device.

[0135] The above-mentioned computer-readable storage medium carries one or more programs. When the above-mentioned one or more programs are executed by the state of charge determination device, the state of charge determination device: applies the state of charge determination method to a battery system, wherein the battery system includes several groups of battery cells, and obtains the open circuit voltage of the several groups of battery cells; determines the voltage comparison results and / or pressure difference data between the several groups of battery cells based on the open circuit voltage; determines the interval to which the state of charge of the battery system belongs according to the voltage comparison results and / or pressure difference data. The voltage comparison results and / or pressure difference data determined by the open circuit voltage of each battery cell can effectively distinguish the interval to which the state of charge belongs, which can improve the accuracy and efficiency of the battery state of charge determination, thereby helping to improve the battery safety and vehicle power.

[0136] Computer program code for performing the operations of the present application may be written in one or more programming languages, or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a stand-alone software package, partially on the user's computer and partially on a remote computer, or entirely on the remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., through the Internet using an Internet service provider).

[0137] The flow charts and block diagrams in the accompanying drawings illustrate the possible architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present application. In this regard, each box in the flow chart or block diagram can represent a module, program segment or a part of code, and the module, program segment or a part of code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order than that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flow chart, and the combination of the boxes in the block diagram and / or flow chart can be implemented by a dedicated hardware-based system that performs the specified function or operation, or can be implemented by a combination of dedicated hardware and computer instructions.

[0138] The modules described in the embodiments of the present application may be implemented in software or hardware, wherein the name of a module does not necessarily limit the unit itself.

[0139] The computer-readable storage medium provided herein stores computer-readable program instructions (i.e., a computer program) for executing the aforementioned state-of-charge determination method, thereby resolving the technical problem of state-of-charge determination. Compared to the prior art, the computer-readable storage medium provided herein has the same beneficial effects as the state-of-charge determination method provided in the aforementioned embodiments, and therefore is not further elaborated here.

[0140] The present application also provides a computer program product, comprising a computer program, which implements the steps of the above-mentioned state of charge determination method when executed by a processor.

[0141] The computer program product provided in this application can solve the technical problem of determining the state of charge. Compared with the prior art, the beneficial effects of the computer program product provided in this application are the same as the beneficial effects of the state of charge determination method provided in the above embodiment, and will not be repeated here.

[0142] The above description is only part of the embodiments of the present application and does not limit the patent scope of the present application. All equivalent structural transformations made by using the contents of the present application specification and drawings under the technical concept of the present application, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A method for determining a state of charge, characterized in that: The method is applied to a battery system, the battery system including a plurality of battery cells, the plurality of battery cells including a first battery cell, a second battery cell, and a third battery cell, wherein the first battery cell, the second battery cell, and the third battery cell have the same specifications, the second battery cell and the first battery cell have the same calibrated capacity but a different charging capacity, and the third battery cell and the first battery cell have the same charging capacity but a different calibrated capacity. The method includes: Obtaining the open circuit voltages of the plurality of battery cells; Determining voltage comparison results and / or voltage difference data between the plurality of groups of battery cells based on the open circuit voltage; The interval to which the state of charge of the battery system belongs is determined according to the voltage comparison result and / or the pressure difference data.

2. The method for determining the state of charge according to claim 1, wherein: The charging capacity of the second battery cell is lower than the charging capacity of the first battery cell, and the rated capacity of the third battery cell is lower than the rated capacity of the first battery cell. The step of determining the voltage comparison results and / or voltage difference data between the plurality of battery cell groups based on the open circuit voltage includes: Comparing the open circuit voltages of the first battery cell, the second battery cell, and the third battery cell to obtain a voltage comparison result of the first battery cell, the second battery cell, and the third battery cell; If the open circuit voltage of the first battery cell is equal to the open circuit voltage of the third battery cell in the voltage comparison result, the difference between the open circuit voltages of the first battery cell and / or the third battery cell and the second battery cell is calculated to obtain the voltage difference data between the first battery cell and / or the third battery cell and the second battery cell.

3. The method for determining the state of charge according to claim 1, wherein: The interval to which the state of charge belongs includes several intervals, and different voltage comparison results and / or pressure difference data correspond to different intervals to which the state of charge belongs.

4. The method for determining the state of charge according to claim 3, wherein: The multiple intervals include a first interval, a second interval, a third interval, and a fourth interval, a lower limit value of the first interval is greater than or equal to an upper limit value of the second interval, a lower limit value of the second interval is greater than or equal to an upper limit value of the third interval, and a lower limit value of the third interval is greater than or equal to an upper limit value of the fourth interval, and the step of determining the interval to which the state of charge of the battery system belongs based on the voltage comparison result and / or the pressure difference data includes: If the open circuit voltage of the second battery cell is greater than the open circuit voltage of the third battery cell in the voltage comparison result, determining that the state of charge is in the fourth interval; If, in the voltage comparison result, the open circuit voltage of the first battery cell is greater than the open circuit voltage of the third battery cell, and the open circuit voltage of the third battery cell is greater than the open circuit voltage of the second battery cell, determining that the state of charge is in the third range; When the voltage difference data between the first battery cell and / or the third battery cell and the second battery cell is greater than a preset voltage difference threshold, determining that the state of charge is in the second range; When the voltage difference data between the first battery cell and / or the third battery cell and the second battery cell is less than or equal to a preset voltage difference threshold, it is determined that the state of charge is in the first range.

5. The method for determining the state of charge according to claim 4, wherein: Before the step of determining that the state of charge is in the second range when the voltage difference data between the first battery cell and / or the third battery cell and the second battery cell is greater than a preset voltage difference threshold, the step further includes: When the battery system enters a current stable operating condition, recording the open circuit voltages of the first battery cell, the second battery cell, and the third battery cell at each moment within a first preset time period; Calculating the difference in open circuit voltage between the first battery cell and / or the third battery cell and the second battery cell at each time to obtain voltage difference recording data; The pressure difference recording data is smoothed to obtain a pressure difference change curve, and the preset pressure difference threshold is determined according to the pressure difference change curve.

6. The method for determining the state of charge according to claim 1, wherein: The charging capacity of the second battery cell is lower than the charging capacity of the first battery cell, and the rated capacity of the third battery cell is lower than the rated capacity of the first battery cell.

7. A device for determining state of charge, characterized in that: The device is applied to a battery system, the battery system including a plurality of battery cells, the plurality of battery cells including a first battery cell, a second battery cell, and a third battery cell, wherein the first battery cell, the second battery cell, and the third battery cell have the same specifications, the second battery cell and the first battery cell have the same rated capacity but a different charging capacity, and the third battery cell and the first battery cell have the same charging capacity but a different rated capacity. The device includes: An acquisition module, configured to acquire the open circuit voltages of the plurality of battery cells; a comparison module, configured to determine voltage comparison results and / or voltage difference data between the plurality of groups of battery cells based on the open circuit voltage; A determination module is used to determine the interval to which the state of charge of the battery system belongs based on the voltage comparison result and / or the pressure difference data.

8. A battery system, characterized in that: The battery system includes several groups of battery cells, wherein the several groups of battery cells include a first battery cell, a second battery cell and a third battery cell. The specifications of the first battery cell, the second battery cell and the third battery cell are the same. The second battery cell has the same calibrated capacity as the first battery cell and a different charging capacity. The third battery cell has the same charging capacity as the first battery cell and a different calibrated capacity.

9. A storage medium, characterized in that: The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, the steps of the method for determining the state of charge according to any one of claims 1 to 6 are implemented.

10. A computer program product, characterized in that The computer program product comprises a computer program, which, when executed by a processor, implements the steps of the state of charge determination method according to any one of claims 1 to 6.

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