Battery system and method for determining initial state of charge (SOC) when it is powered on

Abstract

This application relates to the field of energy storage technologies, and particularly to a battery system and a method for determining the initial SOC when the battery system is powered on. The method includes: obtaining the static duration of the battery system after it is powered on and since the last shutdown, and determining whether the static duration has not reached a preset duration; if not, the compensation voltage is 0; if so, obtaining the voltage state, battery temperature, equivalent circuit model and model parameters of the battery in the battery system in the static state after it is powered on; calculating the compensation voltage based on the static duration, battery temperature, voltage state, equivalent circuit model and model parameters, so as to obtain an accurate compensation voltage when the battery system is powered on, and further obtain an accurate open-circuit voltage, and further obtain an accurate initial SOC of the battery system by querying the OCV-SOC table, thereby improving the monitoring accuracy of the battery management system and the reliability and safety of the battery system.

Description

Technical Field

[0001] This application relates to the technical field of energy storage, in particular to a battery system and a method for determining the initial State of Charge (SOC) when the battery system is powered on. Background Art

[0002] The State of Charge (SOC) of a battery system is a research focus and difficulty in the field of battery system state estimation, and it is also a key monitoring point of the Battery Management System (BMS) in the battery system. The SOC reflects the proportion of the current remaining power of the battery system to the total capacity, which is crucial for ensuring the safe and efficient operation of the battery.

[0003] In SOC estimation, the Ampere-Hour Counting method is one of the most widely used methods. This method estimates the SOC by accumulating the current during the charge and discharge process of the battery. However, the Ampere-Hour Counting method highly depends on the accuracy of the initial SOC value. If the initial SOC value is inaccurate, all subsequent calculations will be affected, and the error of the initial SOC will gradually accumulate over time, resulting in a large deviation in the final SOC estimation value. Therefore, improving the accuracy of the initial SOC when the battery system is powered on can greatly reduce the SOC estimation error after power-on.

[0004] To obtain the accurate SOC of the battery system, it is necessary to accurately determine the initial SOC when the battery system is powered on. In the prior art, there are mainly two methods for determining the initial SOC when the battery system is powered on.

[0005] One is to maintain the SOC recorded at the last shutdown. This method is simple and easy to implement, but it has significant defects. Since the battery will self-discharge during the off period, there is a large difference between the actual remaining capacity and the recorded SOC value. Therefore, the initial SOC recorded by this method is often inaccurate.

[0006] Second, based on the open circuit voltage of the battery system when it is powered on, the initial SOC is obtained by querying the OCV-SOC table (Open Circuit Voltage - State of Charge table). The effectiveness of this method depends on the battery system having been static for a sufficient length of time (usually more than 30 minutes) before powering on to ensure that the chemical reactions inside the battery reach an equilibrium state; if the interval between power-on and power-off is short, this method will introduce large errors. On the other hand, due to the existence of the compensation voltage (i.e., the voltage changes caused by factors such as battery system temperature and self-discharge during the sampling process of the battery system), the actually measured open circuit voltage may not be accurate. To obtain an accurate open circuit voltage, it is necessary to accurately measure and compensate for these voltage changes. Summary of the Invention

[0007] In view of the above problems, the present application provides a battery system and a method for determining the initial SOC when it is powered on, which overcomes the above problems or at least partially solves the technical problem of obtaining an accurate compensation voltage.

[0008] According to one aspect of the present application, a method for determining the compensation voltage of a battery system is provided. The method includes: obtaining the static duration of the battery system after power-on since the last power-off, and determining whether the static duration has not reached a preset duration; if not, the compensation voltage is 0; if so, obtaining the voltage state, battery temperature, equivalent circuit model and model parameters of the battery in the battery system in the static state after power-on; calculating the compensation voltage according to the static duration, battery temperature, voltage state, equivalent circuit model and model parameters.

[0009] In an alternative manner, calculating the compensation voltage according to the static duration, battery temperature, voltage state, equivalent circuit model and model parameters includes: when the voltage state is a boosting state, calculating the compensation voltage according to the static duration, battery temperature, equivalent circuit model and model parameters; when the voltage state is a bucking state, obtaining the bucking speed and determining whether the bucking speed is greater than a preset speed; if so, calculating the compensation voltage according to the static duration, battery temperature, equivalent circuit model and model parameters; if not, the compensation voltage is 0; when the voltage state is a stable state, the compensation voltage is 0.

[0010] In an alternative manner, calculating the compensation voltage according to the static duration, battery temperature, equivalent circuit model and model parameters includes: determining whether the battery temperature is greater than a preset temperature; if so, calculating the compensation voltage according to the static duration, equivalent circuit model and model parameters; if not, calculating the compensation voltage according to the static duration, battery temperature, preset temperature, equivalent circuit model and model parameters.

[0011] In an alternative approach, calculating the compensation voltage based on the standing duration, equivalent circuit model, and model parameters includes: when the equivalent circuit model is a second-order RC model, the formula for calculating the compensation voltage is Formula A1, and Formula A1 is:

[0012] ;

[0013] is the compensation voltage, V 1 is the first parameter, V 2 is the second parameter, t is the standing duration, R 1 is the electrochemical polarization internal resistance, C 1 is the electrochemical polarization capacitance, R 2 is the concentration difference polarization resistance, C 2 is the concentration difference polarization capacitance.

[0014] In an alternative approach, calculating the compensation voltage based on the standing duration, equivalent circuit model, and model parameters includes: when the equivalent circuit model is a Thevenin model, the formula for calculating the compensation voltage is Formula A2, and Formula A2 is:

[0015]

[0016] is the compensation voltage, V 1 is the first parameter, t is the standing duration, R 1 is the electrochemical polarization internal resistance, C 1 is the electrochemical polarization capacitance.

[0017] In an alternative approach, calculating the compensation voltage based on the standing duration, equivalent circuit model, and model parameters includes: when the equivalent circuit model is a PNGV model, the formula for calculating the compensation voltage is Formula A3, and Formula A3 is:

[0018]

[0019] wherein, is the compensation voltage, V 1 is the first parameter, t is the standing duration, R 1 is the electrochemical polarization internal resistance, C 1 is the electrochemical polarization capacitance, V 3 is the third parameter.

[0020] In an alternative approach, calculating the compensation voltage based on the standing duration, equivalent circuit model, and model parameters includes: when the equivalent circuit model is a GNL model, the formula for calculating the compensation voltage is Formula A4, and Formula A4 is:

[0021]

[0022] Among them, is the compensation voltage, V 1 is the first parameter, V 2 is the second parameter, V 3 is the third parameter, t is the standing time, R 1 is the electrochemical polarization internal resistance, C 1 is the electrochemical polarization capacitance, R 2 is the concentration polarization resistance, C 2 is the concentration polarization capacitance.

[0023] In an optional manner, the formula for calculating the compensation voltage according to the standing time, battery temperature, preset temperature, equivalent circuit model and model parameters is:

[0024]

[0025] Among them, is the compensation voltage when the battery temperature is not greater than the preset temperature, Kb is the temperature correction coefficient, M is the preset temperature, T is the battery temperature, is the compensation voltage when the battery temperature is greater than the preset temperature.

[0026] In an optional manner, the value of the first parameter is 0.02, the value of the second parameter is 0.16, and the value of the third parameter is 0.01.

[0027] According to one aspect of the present application, a method for determining the initial SOC of a battery system is provided. The battery system includes a plurality of cell units. The method includes: obtaining the voltages of each cell unit to obtain a plurality of unit voltages, and obtaining the maximum voltage and the minimum voltage among the plurality of unit voltages; according to the compensation voltage, correcting the maximum voltage to obtain a first corrected voltage, and correcting the minimum voltage to obtain a second corrected voltage, and the compensation voltage is calculated by the above method; respectively using the first corrected voltage and the second corrected voltage as the open circuit voltage, querying the OCV-SOC table to obtain the maximum SOC and the minimum SOC; determining the initial SOC of the battery system according to the maximum SOC and the minimum SOC.

[0028] In an alternative approach, the steps of correcting the maximum voltage to obtain a first corrected voltage and correcting the minimum voltage to obtain a second corrected voltage based on the compensation voltage include: when the voltage state is in the boost state, the first corrected voltage is the sum of the maximum voltage and the compensation voltage, and the second corrected voltage is the sum of the minimum voltage and the compensation voltage; when the voltage state is in the buck state, the first corrected voltage is the difference between the maximum voltage and the compensation voltage, and the second corrected voltage is the difference between the minimum voltage and the compensation voltage; when the voltage state is in the stable state, the first corrected voltage is the maximum voltage and the second corrected voltage is the minimum voltage.

[0029] In an alternative approach, the steps of determining the initial state of charge (SOC) of the battery system based on the maximum SOC and the minimum SOC include: obtaining the end SOC of the battery system at the time of the previous shutdown; determining whether the end SOC is within the range defined by the maximum SOC and the minimum SOC; if so, determining the end SOC as the initial SOC of the battery system; if not, when the end SOC is greater than the maximum SOC, determining the maximum SOC as the initial SOC of the battery system; when the end SOC is less than the minimum SOC, determining the minimum SOC as the initial SOC of the battery system.

[0030] In an alternative approach, the steps of using the first corrected voltage and the second corrected voltage as the open-circuit voltage respectively and querying the OCV-SOC table to obtain the maximum SOC and the minimum SOC include: using the first corrected voltage and the second corrected voltage as the open-circuit voltage respectively, and querying the T-OCV-SOC table according to the temperature of the battery system to obtain the maximum SOC and the minimum SOC.

[0031] According to one aspect of the embodiments of the present application, a battery system is provided. The battery system includes: at least one processor, and a memory communicatively connected to the at least one processor. The memory stores instructions executable by the at least one processor. The instructions are executed by the at least one processor to enable the at least one processor to execute the method as described above.

[0032] According to one aspect of the embodiments of the present application, a computer-readable storage medium is provided. The computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the processor executes the steps of the method as described above.

[0033] The beneficial effects of the present application include: through the method for determining the compensation voltage when the battery system is powered on, an accurate compensation voltage when the battery system is powered on can be obtained, and then an accurate open-circuit voltage can be obtained. Further, an accurate initial SOC of the battery system can be obtained by querying the OCV-SOC table, improving the monitoring accuracy of the battery management system and the reliability and safety of the battery system. Description of the Drawings

[0034] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplary illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements, unless otherwise stated, the drawings in the figures do not constitute a scale limitation.

[0035] Figure 1 is a schematic diagram of a battery system provided by an embodiment of the present application;

[0036] Figure 2 is a schematic diagram of the hardware structure of the BMS module provided by an embodiment of the present application;

[0037] Figure 3 is a schematic flowchart of a method for determining the compensation voltage when the battery system provided by an embodiment of the present application is powered on;

[0038] Figure 4 is a voltage response diagram of the battery system provided by an embodiment of the present application under pulse discharge conditions;

[0039] Figure 5 is a schematic diagram of a second-order RC model provided by an embodiment of the present application;

[0040] Figure 6 is a schematic diagram of a Thevenin model provided by an embodiment of the present application;

[0041] Figure 7 is a schematic diagram of a PNGV model provided by an embodiment of the present application;

[0042] Figure 8 is a schematic diagram of a GNL model provided by an embodiment of the present application;

[0043] Figure 9 is a schematic flowchart of a method for calculating the compensation voltage provided by an embodiment of the present application;

[0044] Figure 10 is a schematic flowchart of a method for determining the initial SOC when the battery system provided by an embodiment of the present application is powered on;

[0045] Figure 11 is a schematic flowchart of a method for determining the SOC of the battery system provided by an embodiment of the present application;

[0046] Figure 12 is a schematic diagram of a device for determining the compensation voltage when the battery system provided by an embodiment of the present application is powered on;

[0047] Figure 13 is a schematic diagram of a device for determining the initial SOC when the battery system provided by an embodiment of the present application is powered on. Detailed implementation manners

[0048] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will clearly and completely describe the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application. Apparently, the described embodiments are some, but not all, of the embodiments of this application. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art fall within the scope of protection of this application.

[0049] In addition, the technical features involved in the embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0050] Please refer to Figure 1 , Figure 1 which is a schematic diagram of the system provided by the embodiments of this application. This system is applicable to a battery system, a method for determining a compensation voltage when the battery system is powered on, and a method for determining an initial SOC when the battery system is powered on. The battery system includes a battery 100 and a BMS module 200. The battery 100 can specifically have various setting manners, not limited to Figure 1 the situation shown.

[0051] The battery 100 includes a plurality of cell units 10, and the plurality of cell units 10 are connected in series to form the battery 100. Each cell unit 10 can be composed of one cell or multiple parallel-connected cells.

[0052] The battery 100 can be a lithium-ion battery, and lithium-ion batteries mainly include consumer batteries, power batteries, and energy storage batteries. Among them, consumer batteries usually require small size, light weight, high energy density, and long cycle life, and are widely used in personal electronic devices such as mobile phones, laptops, tablets, digital cameras, and portable music players. Among them, power batteries are mainly used in transportation tools such as new energy vehicles, electric bicycles, and electric trains to provide the instantaneous high power output required by the vehicle to support operations such as acceleration and climbing. Among them, energy storage batteries are mostly used in battery energy storage systems for renewable energy such as solar energy, wind energy, and hydropower, as well as in occasions such as power grid peak shaving and frequency modulation, standby power supplies, and microgrids, and are mainly used for long-term energy storage and stable release.

[0053] It can be understood that, in some embodiments, the battery system further includes a BMS (Battery Management System) module 200. The BMS module 200 is responsible for monitoring the operating status of the battery cell unit 10 to ensure the safe and reliable operation of the battery cell unit 10. The BMS module 200 can actually monitor and collect the state parameters of the battery cell unit 10 (including but not limited to the voltage, current, temperature, insulation resistance, etc. of the battery cell 10), and perform necessary analysis and calculations on the relevant state parameters to obtain more state evaluation parameters, and realize effective control of the battery cell unit 10 according to specific protection control strategies to ensure the safe and reliable operation of the entire battery cell unit 10. At the same time, the BMS module 200 can perform information interaction with other external devices 300 (such as PCS, EMS, fire protection system, etc.) through its own communication interface and analog / digital input interface to form a linkage control to ensure the safe, reliable and efficient operation of the battery cell unit 10.

[0054] Embodiment 1

[0055] Before introducing the method for determining the compensation voltage of the battery system in detail, the hardware structure of the BMS module 200 provided in the embodiments of the present application will be described.

[0056] Please refer to Figure 2 , Figure 2 which is a schematic diagram of the hardware structure of the BMS module 200 provided in the embodiments of the present application, and it can execute the method for determining the compensation voltage of the battery system and the method for determining the initial SOC of the battery system. The BMS module 200 includes:

[0057] At least one processor 21 and a memory 22 that are communicatively connected ( Figure 2 taking bus connection and one processor as an example in Figure 2 ). Those of ordinary skill in the art can understand that Figure 2 the structure shown is only schematic and does not limit the structure of the above BMS module 200. For example, the BMS module 200 may further include more or fewer components than Figure 2 shown in

[0058] Among them, the processor 21 is used to provide computing and control capabilities, and control the BMS module 200 to execute any method provided in the following embodiments of the present application, and then perform corresponding management on the battery cell 10.

[0059] It can be understood that the processor 21 can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0060] The memory 22, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs, non-transitory computer-executable programs, and modules, such as the program instructions / modules corresponding to the various calculation methods in the embodiments of the present application. By running the non-transitory software programs, instructions, and modules stored in the memory 22, the processor 21 can implement the various calculation methods in any of the following method embodiments. The memory 22 can include a high-speed random access memory, and can also include a non-transitory memory, such as at least one magnetic disk storage device, a flash memory device, or other non-transitory solid-state storage devices. In some embodiments, the memory 22 can also include a memory remotely provided relative to the processor, and these remote memories can be connected to the processor through a network. Examples of the above network include but are not limited to the Internet, an enterprise intranet, a local area network, a mobile communication network, and combinations thereof.

[0061] Embodiment 2

[0062] The embodiments of the present application also provide a non-volatile computer-readable storage medium, and the non-volatile computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are executed by the battery system to implement the various calculation methods in any of the following method embodiments.

[0063] The embodiments of the present application provide a computer program product, including a calculation program stored on a non-volatile computer-readable storage medium. The computer program includes program instructions, and when the program instructions are executed by a computer, the computer is caused to implement the various calculation methods in any of the following method embodiments.

[0064] Through the description of the above embodiments, those of ordinary skill in the art can clearly understand that each embodiment can be implemented by means of software plus a general hardware platform, and of course, it can also be implemented by hardware. Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above methods. Among them, the storage medium can be a magnetic disk, an optical disc, a read-only memory (ROM), or a random access memory (RAM), etc.

[0065] Embodiment 3

[0066] Next, a method for determining the compensation voltage when the battery system is powered on provided by the embodiments of the present application will be discussed. Please refer to Figure 3 , Figure 3 is a schematic flowchart of the method for determining the compensation voltage when the battery system is powered on provided by the embodiments of the present application. The method includes the following steps:

[0067] Step S10, obtain the static duration of the battery system after it is powered on and since the last shutdown, and determine whether the static duration has not reached the preset duration.

[0068] Among them, the static duration refers to the static duration of the battery system in a static state since the last shutdown until the current power-on.

[0069] Its static state is divided into two segments. One segment is the state of the battery system from the last shutdown to the current power-on, and the other segment is the state of the battery where it neither charges nor discharges until the first charge / discharge after the current power-on.

[0070] For obtaining the static duration, it can be obtained through the internal hardware clock of the battery system and / or the network time protocol.

[0071] Step S20, if not, the compensation voltage is 0.

[0072] If the static duration of the battery system in the static state reaches the preset duration, it is determined that the compensation voltage is zero.

[0073] In some embodiments, when the time during which the battery system does not perform charging, discharging, or any other operation that may significantly affect the state of the battery system exceeds a preset threshold (e.g., 5 minutes), it is determined that the battery system is in a static state, and the static duration during which the battery system is in the static state is accumulated. When the static duration is greater than the preset duration (e.g., 30 minutes), it is determined that the battery system is not affected by the compensation voltage, that is, the compensation voltage is determined to be zero. At this time, the initial SOC of the battery system can be directly obtained by querying the OCV-SOC table based on the open-circuit voltage of the battery system.

[0074] Step S30, if so, obtain the voltage state, battery temperature, equivalent circuit model and model parameters of the battery in the battery system in the static state after startup.

[0075] When the static duration does not reach the preset duration, it indicates that the chemical reaction inside the battery has not reached an equilibrium state. Therefore, it is necessary to obtain various state parameters of the battery, including: voltage state, battery temperature, and the equivalent circuit model and model parameters of the battery, so as to accurately determine the compensation voltage of the battery system for different voltage states.

[0076] The voltage state of the battery can be a boosting state, a bucking state, or a stable state. Among them, the boosting state is the state in which the battery voltage continuously increases, the bucking state is the state in which the battery voltage continuously decreases, and the stable state is the state in which the battery is stable at a certain voltage value or has only slight fluctuations.

[0077] Please refer to Figure 4 , Figure 4 is the voltage response diagram of the battery under the pulse discharge condition provided by the embodiment of the present application. Among them, section AB: the voltage jump section when the current is loaded; section BC: the section where the voltage slowly changes after the current is loaded; section CD: the voltage jump section after the current is unloaded; section DE: the section where the voltage slowly changes after the current is unloaded. After the battery system finishes discharging, it enters the static state. For example Figure 4 in section DE of , the static state in this DE section is the research focus of the embodiment of the present application. Among them, section DF is the boosting state where the voltage rebounds, and section FE is the stable state of the voltage.

[0078] Similarly, when it enters the static state after charging, in the initial stage of the static state, there will also be a voltage rebound first, that is, it enters the bucking state, and then enters the stable state.

[0079] The battery temperature of the battery system can be obtained according to the built-in temperature sensor in the battery system, or can be obtained according to the temperature test circuit.

[0080] The equivalent circuit model of a battery aims to simulate the electrical characteristics of the battery by simplifying the circuit, facilitating the analysis and prediction of battery performance. These models can help us understand the behavior of the battery under different operating conditions, such as key indicators like voltage, current, output power, and efficiency. Common battery equivalent circuit models include the Rint model (internal resistance model), Thevenin model (also known as the first-order RC (Resistance-Capacitance) model), second-order RC model, PNGV model (Partnership for a New Generation of Vehicles model), GNL model (Generalized Nonlinear model), etc. Among them, the second-order RC model can better balance model accuracy and model complexity, winning wide recognition and adoption in the industry and becoming the preferred solution in the field of battery management system (BMS) design and performance optimization. For example, Figure 5 、 6 Figures 7 and 8 are the second-order RC model, Thevenin model, PNGV model, and GNL model respectively. Among them, U oc is the open-circuit voltage, U L is the battery terminal voltage, and the parameters such as resistance and capacitance of each model are as follows: R 0 is the ohmic internal resistance, R1 is the electrochemical polarization resistance, C1 is the electrochemical polarization capacitance, R2 is the concentration difference polarization resistance, C2 is the concentration difference polarization capacitance, C q is the equivalent capacitance, R S is the self-discharge resistance.

[0081] When the battery system is in a static state (i.e., neither charging nor discharging) but has not reached the equilibrium state, the battery system will exhibit characteristics including electrochemical polarization and concentration difference polarization. Electrochemical polarization refers to the change in potential difference caused by electrochemical reactions during the charging or discharging process of the battery system, while concentration difference polarization refers to the change in potential difference caused by uneven electrolyte concentration inside the battery system. Based on the electrochemical polarity exhibited by the battery system, the electrochemical polarization resistance and electrochemical polarization capacitance of the battery system can be obtained; based on the concentration difference polarity exhibited by the battery system, the concentration difference polarization resistance and concentration difference polarization capacitance of the battery system can be obtained.

[0082] The identification (acquisition) of parameters such as resistance and capacitance in each model can be carried out through existing common experimental methods. For example:

[0083] 1) Constant current charge and discharge test: Charge and discharge the battery at a constant current, and record the change of voltage over time. By analyzing the charge and discharge curves, the ohmic internal resistance and electrochemical polarization resistance of the battery can be estimated.

[0084] 2) Pulse test: Apply a short current pulse to the battery and measure the instantaneous change of voltage before and after the pulse. This method can be used to estimate the dynamic internal resistance of the battery, including the RC links with fast and slow responses.

[0085] 3) AC impedance spectroscopy: Apply a small-amplitude AC signal (usually in the millivolt level) and measure the impedance of the battery over a wide frequency range. It can provide impedance information of the battery at different time scales, thereby identifying the parameters of the RC links.

[0086] 4) Step response test: Apply a step change in voltage or current and observe the dynamic response of the battery voltage. The step response can reveal the transient characteristics of the battery and help identify the RC time constant.

[0087] 5) Hybrid Pulse Power Characterization (HPPC) test: As a comprehensive dynamic test method, especially combining the characteristics of pulse test and step response test, it includes a series of pulse charge and discharge of the battery at different states of charge (SOC), and also considers the regenerative ability of the battery, providing a more comprehensive view of battery performance.

[0088] For example: The method to obtain the electrochemical polarization internal resistance can be to measure the relationship between voltage and current of the battery system at different discharge depths, and calculate the internal resistance using Ohm's law.

[0089] The method to obtain the electrochemical polarization capacitance can be to apply a small-amplitude AC sine wave voltage to the battery system, measure the AC impedance of the battery system, and obtain the electrochemical polarization capacitance through AC impedance spectroscopy analysis.

[0090] The method to obtain the concentration difference polarization resistance can be to measure the change relationship between the voltage and current of the battery system during the discharge or charge process of the battery system, calculate the voltage change caused by the current change, and thus obtain the concentration difference polarization resistance.

[0091] The method to obtain the concentration difference polarization capacitance can be to perform an AC impedance test on the battery system, analyze the frequency range related to concentration difference polarization in the AC impedance spectrum, and calculate to obtain the concentration difference polarization capacitance.

[0092] Step S40, calculate the compensation voltage according to the static duration, battery temperature, voltage state, equivalent circuit model and model parameters.

[0093] Among them, when the voltage state is in the boost state, the compensation voltage is calculated according to the standing time, the battery temperature, the equivalent circuit model, and the model parameters.

[0094] When the voltage state is in the buck state, the buck speed is obtained, and it is determined whether the buck speed is greater than the preset speed; if so, the compensation voltage is calculated according to the standing time, the battery temperature, the equivalent circuit model, and the model parameters; if not, the compensation voltage is 0.

[0095] Among them, the calculation method of the buck speed of the battery system can be to measure the voltage change amount of the battery system within a specific time, and then divide it by this time period, and the quotient obtained is the buck speed. Specifically, a time window can be set, for example, 10 seconds, measure the voltage change amount of the battery system within these 10 seconds, and then divide this voltage change amount by 10 seconds, and the value obtained is the current buck speed.

[0096] When the buck speed is greater than the preset speed, it is considered that the battery is not in a stable state; on the contrary, it is considered that the battery is in a stable state, and at this time, the compensation voltage is determined to be zero.

[0097] Among them, the preset speed can be determined according to actual experience, for example, it can be 4mV / 1000s.

[0098] When the voltage state is in the stable state, the compensation voltage is 0.

[0099] All in all, when the voltage state is in the boost state or the fast buck state, the compensation voltage is calculated according to the standing time, the battery temperature, the equivalent circuit model, and the model parameters. Please refer to Figure 9 , and the specific steps are as follows:

[0100] S41. Determine whether the battery temperature is greater than the preset temperature.

[0101] Among them, the preset temperature is usually room temperature, and it can be 20 degrees Celsius.

[0102] S42. If so, calculate the compensation voltage according to the standing time, the equivalent circuit model, and the model parameters (Formula A).

[0103] According to the differences in the equivalent circuit model and the model parameters, the calculation method of the compensation voltage is also different. Specifically as follows:

[0104] S421. When the equivalent circuit model is a second-order RC model, the formula for calculating the compensation voltage is Formula A1, and Formula A1 is:

[0105]

[0106] is the compensation voltage, V 1 is the first parameter,V 2 is the second parameter, t which is the static duration, R 1 is the electrochemically polarized internal resistance, C 1 is the electrochemically polarized capacitance, R 2 is the concentration polarization resistance, C 2 is the concentration polarization capacitance.

[0107] S422. When the equivalent circuit model is the Thevenin model, the formula for calculating the compensation voltage is Formula A2, and Formula A2 is:

[0108]

[0109] is the compensation voltage, V 1 is the first parameter, t which is the static duration, R 1 is the electrochemically polarized internal resistance, C 1 is the electrochemically polarized capacitance.

[0110] S423. When the equivalent circuit model is the PNGV model, the formula for calculating the compensation voltage is Formula A3, and Formula A3 is:

[0111]

[0112] where, is the compensation voltage, V 1 is the first parameter, t which is the static duration, R 1 is the electrochemically polarized internal resistance, C 1 is the electrochemically polarized capacitance, V 3 is the third parameter.

[0113] S424. When the equivalent circuit model is the GNL model, the formula for calculating the compensation voltage is Formula A4, and Formula A4 is:

[0114]

[0115] where, is the compensation voltage, V 1 is the first parameter, V 2 is the second parameter, V 3 is the third parameter, t which is the static duration, R 1 is the electrochemically polarized internal resistance, C 1 is the electrochemically polarized capacitance, R 2 is the concentration polarization resistance, C 2 is the concentration polarization capacitance.

[0116] For the standing time in steps S421 - S424, its measurement unit can be seconds; the first parameter V 1. The second parameter V 2. The third parameter V 3 is determined according to experience. In some embodiments, the value of the first parameter V 1 is 0.02, the value of the second parameter V 2 is 0.16, and the value of the third parameter V 3 is 0.01.

[0117] S43. If not, then calculate the compensation voltage according to the standing time, battery temperature, preset temperature, equivalent circuit model and model parameters (Formula B).

[0118] It should be noted that the compensation voltage of the battery system is also affected by the temperature of the battery system. In some embodiments, the compensation voltage is calculated according to the following Formula B

[0119] Formula B is:

[0120]

[0121] Wherein, is the compensation voltage when the battery temperature is not greater than the preset temperature, Kb is the temperature correction coefficient, M is the preset temperature, T is the temperature of the battery system, is the compensation voltage of any one of steps S421 - S424.

[0122] Among them, for the above temperature correction coefficient Kb , the acquisition method can be to obtain the ohmic internal resistance of the battery at different temperatures; the ohmic internal resistance at different temperatures divided by the ohmic internal resistance at normal temperature is the temperature correction coefficient at different temperatures Kb .

[0123] Through the above Formula B, the compensation voltage when the battery temperature is not greater than the preset temperature can be obtained, thereby reducing the influence of temperature on the accuracy of the obtained compensation voltage.

[0124] In an embodiment of the present application, by obtaining the static duration of the battery system after it is powered on since the last shutdown and determining whether the static duration has not reached a preset duration; if not, the compensation voltage is 0; if so, obtain the voltage state, battery temperature, equivalent circuit model and model parameters of the battery in the battery system in the static state after being powered on; calculate the compensation voltage according to the static duration, battery temperature, voltage state, equivalent circuit model and model parameters, then an accurate compensation voltage when the battery system is powered on can be obtained, and further an accurate open-circuit voltage can be obtained, and an accurate initial SOC of the battery system can be further obtained by querying the OCV-SOC table, improving the monitoring accuracy of the battery management system and the reliability and safety of the battery system.

[0125] Embodiment 4

[0126] Hereinafter, a method for determining the initial SOC of the battery system provided in the embodiments of the present application will be discussed. Please refer to Figure 10 , Figure 10 which is a schematic flowchart of the method for determining the initial SOC of the battery system provided in the embodiments of the present application. The battery system includes a plurality of cell units connected in series. The method for determining the initial SOC when the battery system is powered on includes:

[0127] Step S1, obtain the voltages of each cell unit to obtain a plurality of unit voltages, and obtain the maximum voltage and the minimum voltage among the plurality of unit voltages.

[0128] The battery system is internally provided with a BMS module, which can obtain the voltages of each cell unit, thereby obtaining a plurality of unit voltages, and further obtaining the maximum voltage and the minimum voltage among the plurality of unit voltages.

[0129] Step S2, according to the compensation voltage, correct the maximum voltage to obtain a first corrected voltage, and correct the minimum voltage to obtain a second corrected voltage. The compensation voltage is calculated by the method in Embodiment 3.

[0130] In some embodiments, when the voltage state is the boosting state, the first corrected voltage is the sum of the maximum voltage and the compensation voltage, and the second corrected voltage is the sum of the minimum voltage and the compensation voltage; when the voltage state is the bucking state, the first corrected voltage is the difference between the maximum voltage and the compensation voltage, and the second corrected voltage is the difference between the minimum voltage and the compensation voltage; when the voltage state is the stable state, the first corrected voltage is the maximum voltage, and the second corrected voltage is the minimum voltage.

[0131] Through the above method, according to the compensation voltage, the maximum voltage is corrected to obtain the first corrected voltage, and the minimum voltage is corrected to obtain the second corrected voltage. Thus, for different voltage states, such as boost state, buck state, and stable state, there will be different methods for the maximum corrected voltage and the minimum voltage. Then, when the battery system is in different working conditions, the accurate open-circuit voltage can be obtained, thereby improving the accuracy of querying the OCV-SOC table based on the open-circuit voltage, and further determining the initial SOC of the battery system.

[0132] Step S3: Respectively use the first corrected voltage and the second corrected voltage as the open-circuit voltage, query the OCV-SOC table, and obtain the maximum SOC and the minimum SOC.

[0133] Among them, the OCV-SOC table is the Open Circuit Voltage - State of Charge table. When the battery system leaves the factory, a corresponding relationship table between OCV and SOC is preset and stored in the BMS module. Then, the corresponding state of charge can be queried through the determined open-circuit voltage of the battery system.

[0134] In some embodiments, the step of respectively using the first corrected voltage and the second corrected voltage as the open-circuit voltage, querying the OCV-SOC table, and obtaining the maximum SOC and the minimum SOC, that is, step S3 includes: respectively using the first corrected voltage and the second corrected voltage as the open-circuit voltage, and according to the temperature of the battery system, query the T-OCV-SOC table to obtain the maximum SOC and the minimum SOC. That is, the influence of the temperature of the battery system on the SOC of the battery system is introduced, so that on the one hand, the accuracy of the obtained maximum SOC and minimum SOC is high, and on the other hand, the operation stability and safety of the battery system can be guaranteed.

[0135] Step S4: Determine the initial SOC of the battery system according to the maximum SOC and the minimum SOC.

[0136] There are many methods to determine the initial SOC of the battery system according to the maximum SOC and the minimum SOC. For example, taking the average value of the maximum SOC and the minimum SOC as the initial SOC of the battery system, or other methods can also be adopted. In some embodiments, please refer to Figure 11 , the step of determining the initial SOC of the battery system according to the maximum SOC and the minimum SOC, that is, step S4 includes:

[0137] Step S401: Obtain the terminal SOC of the battery system when it was shut down last time.

[0138] During the charging and discharging process of the battery system, usually the BMS module will record the electrical parameters of the battery system, such as voltage, current, and the SOC at each stage, so as to obtain the terminal SOC of the battery system when it was shut down last time.

[0139] It should be noted that if the terminal SOC of the battery system when it was shut down last time cannot be queried, the preset SOC value will be used as the terminal SOC when it was shut down last time. Among them, the preset SOC value can be 50%.

[0140] Step S402, determine whether the terminal SOC is within the range limited by the maximum SOC and the minimum SOC. If so, execute step S403; if not, execute step S404.

[0141] Step S403, determine the terminal SOC as the initial SOC of the battery system.

[0142] Step S404, when the terminal SOC is greater than the maximum SOC, determine the maximum SOC as the initial SOC of the battery system; when the terminal SOC is less than the minimum SOC, determine the minimum SOC as the initial SOC of the battery system.

[0143] To facilitate the reader's understanding of the inventive concept of the present application, the method for determining the initial SOC of the battery system of the present application is verified through experiments.

[0144] Experimental method: Take 5 battery systems and let them stand still in an environmental chamber until the test temperature (taking 25°C as an example), and verify the initial SOC of each battery system.

[0145] For any one battery system, first charge / discharge the battery system to the test SOC value (taking the SOC value of 30% as an example), then manually modify the SOC to an incorrect SOC (such as 60%), and shut down; let the battery system stand still for 1 min, 10 min, 20 min, 30 min (corresponding to the above standing time), 60 min respectively. After powering on, observe whether the initial SOC of the battery system is corrected to the test SOC value (such as the above 30%).

[0146] In addition, modify the test temperature and the test SOC value, and repeat the above test.

[0147] When the method for determining the initial SOC of the battery system provided by the embodiment of the present application is used, the initial SOC of each battery system in the test can be corrected to the test SOC value, indicating that the accuracy of the initial SOC determined by the method for determining the initial SOC of the battery system provided by the embodiment of the present application is high and its reliability is good.

[0148] In the embodiment of the present application, by obtaining the voltages of each battery cell unit, a plurality of unit voltages are obtained, and the maximum voltage and the minimum voltage among the plurality of unit voltages are obtained; according to the compensation voltage, the maximum voltage is corrected to obtain the first corrected voltage, and the minimum voltage is corrected to obtain the second corrected voltage, and the compensation voltage is calculated by the method of Embodiment III; the first corrected voltage and the second corrected voltage are respectively used as the open-circuit voltage, and the OCV-SOC table is queried to obtain the maximum SOC and the minimum SOC; according to the maximum SOC and the minimum SOC, the initial SOC of the battery system is determined, so that the initial SOC of the battery system can be accurately determined, thereby providing an accurate reference basis for subsequent charge and discharge management. In practical applications, this determination method can improve the usage efficiency and lifespan of the battery system and reduce the degradation of the battery system performance caused by inaccurate estimation of the initial SOC of the battery system.

[0149] Embodiment V

[0150] Hereinafter, the determination device for the compensation voltage when the battery system provided in the embodiment of the present application is powered on will be described. Please refer to Figure 12 , Figure 12 is a schematic diagram of the determination device for the compensation voltage when the battery system provided in the embodiment of the present application is powered on. The determination device 1 for the compensation voltage when the battery system is powered on includes a first judgment module 11, which is used to obtain the static duration after the battery system is powered on and the last shutdown, and judge whether the static duration has not reached the preset duration. If not, it enters the zeroing module 12; if so, it enters the first acquisition module 13; the zeroing module 12 is used to set the compensation voltage to 0; the first acquisition module 13 is used to obtain the voltage state, battery temperature, equivalent circuit model and model parameters of the battery in the battery system in the static state after being powered on; the first calculation module 14 is used to calculate the compensation voltage according to the static duration, battery temperature, voltage state, equivalent circuit model and model parameters.

[0151] In some embodiments, the first calculation module 14 is used to calculate the compensation voltage according to the static duration, battery temperature, equivalent circuit model and model parameters when the voltage state is a boosting state; when the voltage state is a bucking state, obtain the bucking speed and judge whether the bucking speed is greater than the preset speed; if so, calculate the compensation voltage according to the static duration, battery temperature, equivalent circuit model and model parameters; if not, the compensation voltage is 0; when the voltage state is a stable state, the compensation voltage is 0.

[0152] In some embodiments, the first calculation module 14 includes: a first judgment unit 141, configured to judge whether the battery temperature is greater than a preset temperature; if so, execute the first calculation unit 142, and if not, execute the second calculation unit 143; a first calculation unit 142, configured to calculate a compensation voltage according to the static duration, an equivalent circuit model, and model parameters; and a second calculation unit 143, configured to calculate a compensation voltage according to the static duration, the battery temperature, the preset temperature, the equivalent circuit model, and the model parameters.

[0153] In some embodiments, when the equivalent circuit model is a second-order RC model, the first calculation unit 142 is specifically configured to calculate the compensation voltage using Formula A1, and Formula A1 is:

[0154] ;

[0155] is the compensation voltage, V 1 is the first parameter, V 2 is the second parameter, t is the static duration, R 1 is the electrochemical polarization internal resistance, C 1 is the electrochemical polarization capacitance, R 2 is the concentration difference polarization resistance, C 2 is the concentration difference polarization capacitance.

[0156] In some embodiments, when the equivalent circuit model is a Thevenin model, the first calculation unit 142 is specifically further configured to calculate the compensation voltage using Formula A2, and Formula A2 is:

[0157]

[0158] is the compensation voltage, V 1 is the first parameter, t is the static duration, R 1 is the electrochemical polarization internal resistance, C 1 is the electrochemical polarization capacitance.

[0159] In some embodiments, when the equivalent circuit model is a PNGV model, the first calculation unit 142 is specifically further configured to calculate the compensation voltage using Formula A3, and Formula A3 is:

[0160]

[0161] Wherein, is the compensation voltage, V 1 is the first parameter, t is the static duration, R 1 is the electrochemical polarization internal resistance, C 1 is the electrochemical polarization capacitance,V 3 is the third parameter.

[0162] In some embodiments, the first calculation unit 142 is further specifically configured to calculate the compensation voltage using Formula A4 when the equivalent circuit model is the GNL model. Formula A4 is:

[0163]

[0164] Wherein, is the compensation voltage, V 1 is the first parameter, V 2 is the second parameter, V 3 is the third parameter, t is the standing time, R 1 is the electrochemical polarization internal resistance, C 1 is the electrochemical polarization capacitance, R 2 is the concentration difference polarization resistance, C 2 is the concentration difference polarization capacitance.

[0165] In some embodiments, the formula of the second calculation unit 143 is:

[0166]

[0167] Wherein, is the compensation voltage when the battery temperature is not greater than the preset temperature, Kb is the temperature correction coefficient, M is the preset temperature, T is the battery temperature, is the compensation voltage when the battery temperature is greater than the preset temperature.

[0168] In some embodiments, the value of the first parameter is 0.02, the value of the second parameter is 0.16, and the value of the third parameter is 0.01.

[0169] In the embodiments of the present application, the first judgment module 11 obtains the standing time of the battery system after startup and since the last shutdown, and determines whether the standing time has not reached the preset time. If not, it enters the zeroing module 12; if so, it enters the first acquisition module 13; the zeroing module 12 sets the compensation voltage to 0; the first acquisition module 13 obtains the voltage state, battery temperature, equivalent circuit model and model parameters of the battery in the battery system in the standing state after startup; the first calculation module 14 calculates the compensation voltage according to the standing time, battery temperature, voltage state, equivalent circuit model and model parameters, so as to obtain an accurate compensation voltage when the battery system starts up, and further obtain an accurate open-circuit voltage, and further obtain an accurate initial SOC of the battery system by querying the OCV-SOC table, improving the monitoring accuracy of the battery system management system and the reliability and safety of the battery system.

[0170] Embodiment Six

[0171] The following will discuss the device for determining the initial SOC when the battery system provided by the embodiments of the present application is powered on. Please refer to Figure 13 , Figure 13 FIG. is a schematic diagram of the device for determining the initial SOC when the battery system provided by the embodiments of the present application is powered on. The device 2 for determining the initial SOC when the battery system is powered on includes a first acquisition part 21 for acquiring the voltages of each battery cell unit to obtain a plurality of unit voltages, and acquiring the maximum voltage and the minimum voltage among the plurality of unit voltages; a correction part 22 for correcting the maximum voltage to obtain a first corrected voltage and correcting the minimum voltage to obtain a second corrected voltage according to the compensation voltage, and the compensation voltage is calculated by the method in Embodiment Three; a query part 23 for respectively using the first corrected voltage and the second corrected voltage as the open-circuit voltage to query the OCV-SOC table to obtain the maximum SOC and the minimum SOC; and a determination part 24 for determining the initial SOC of the battery system according to the maximum SOC and the minimum SOC.

[0172] In some embodiments, the correction part 22 is specifically configured to: when the voltage state is a boosting state, the first corrected voltage is the sum of the maximum voltage and the compensation voltage, and the second corrected voltage is the sum of the minimum voltage and the compensation voltage; when the voltage state is a bucking state, the first corrected voltage is the difference between the maximum voltage and the compensation voltage, and the second corrected voltage is the difference between the minimum voltage and the compensation voltage; when the voltage state is a stable state, the first corrected voltage is the maximum voltage, and the second corrected voltage is the minimum voltage. In some embodiments, the determination part 24 includes: a first acquisition unit 241 for acquiring the end SOC of the battery system when it was powered off last time; a first judgment unit 242 for judging whether the end SOC is within the range defined by the maximum SOC and the minimum SOC. If so, it enters the first determination unit 243. If not, it enters the second determination unit 244; the first determination unit 243 for determining the end SOC as the initial SOC of the battery system; the second determination unit 244 for, when the end SOC is greater than the maximum SOC, determining the maximum SOC as the initial SOC of the battery system; and when the end SOC is less than the minimum SOC, determining the minimum SOC as the initial SOC of the battery system.

[0173] In some embodiments, the query part 23 is specifically configured to respectively use the first corrected voltage and the second corrected voltage as the open-circuit voltage, and query the T-OCV-SOC table according to the temperature of the battery system to obtain the maximum SOC and the minimum SOC.

[0174] In the embodiment of the present application, the first acquisition part 21 acquires the voltages of each battery cell unit to obtain a plurality of unit voltages, and acquires the maximum voltage and the minimum voltage among the plurality of unit voltages; the correction part 22 corrects the maximum voltage according to the compensation voltage to obtain a first corrected voltage, and corrects the minimum voltage to obtain a second corrected voltage, and the compensation voltage is calculated by the method of Embodiment 3; the query part 23 respectively uses the first corrected voltage and the second corrected voltage as the open-circuit voltage, queries the OCV-SOC table, and obtains the maximum SOC and the minimum SOC; the determination part 24 determines the initial SOC of the battery system according to the maximum SOC and the minimum SOC, so that the initial SOC of the battery system can be accurately determined, thereby providing an accurate reference basis for subsequent charge and discharge management. In practical applications, this determination method can improve the usage efficiency and lifespan of the battery system, and reduce the degradation of the battery system performance caused by inaccurate estimation of the initial SOC of the battery system.

[0175] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; under the idea of the present application, the technical features in the above embodiments or different embodiments can also be combined, and the steps can be implemented in any order, and there are many other changes in different aspects of the present application as above. For the sake of brevity, they are not provided in detail; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for determining the initial SOC of a battery system when it is turned on, characterized in that: The battery system includes a plurality of battery cells connected in series. The method includes: Obtaining the voltage of each battery cell unit, obtaining multiple unit voltages, and obtaining the maximum voltage and the minimum voltage among the multiple unit voltages; According to the compensation voltage, the maximum value of the correction voltage is obtained to obtain a first correction voltage, and the minimum value of the correction voltage is obtained to obtain a second correction voltage, including when the voltage state is a boost state, the first correction voltage is the sum of the maximum value of the voltage and the compensation voltage, and the second correction voltage is the sum of the minimum value of the voltage and the compensation voltage; when the voltage state is a step-down state, the first correction voltage is the difference between the maximum value of the voltage and the compensation voltage, and the second correction voltage is the difference between the minimum value of the voltage and the compensation voltage; when the voltage state is a stable state, the first correction voltage is the maximum value of the voltage, and the second correction voltage is the minimum value of the voltage; Taking the first corrected voltage and the second corrected voltage as the open circuit voltage respectively, querying the OCV-SOC table to obtain the maximum SOC value and the minimum SOC value; Determine the initial SOC of the battery system according to the maximum SOC value and the minimum SOC value; Among them, the method for determining the compensation voltage includes: obtaining the static time from the last shutdown of the battery system after it is powered on, and judging whether the static time does not reach the preset time; if not, the compensation voltage is 0; if so, obtaining the voltage state of the battery in the static state after the power is turned on, the battery temperature, the equivalent circuit model and model parameters of the battery in the battery system; calculating the compensation voltage according to the static time, battery temperature, voltage state and equivalent circuit model and model parameters.

2. The method according to claim 1, characterized in that: According to the static time, battery temperature, voltage state, equivalent circuit model and model parameters, the compensation voltage is calculated including: When the voltage state is in a boost state, the compensation voltage is calculated according to the static time, battery temperature, equivalent circuit model and model parameters; When the voltage state is in a step-down state, the step-down speed is obtained to determine whether the step-down speed is greater than a preset speed; if so, the compensation voltage is calculated according to the static time, battery temperature, equivalent circuit model and model parameters; if not, the compensation voltage is 0; When the voltage state is stable, the compensation voltage is 0.

3. The method according to claim 2, characterized in that According to the static time, battery temperature, equivalent circuit model and model parameters, the compensation voltage is calculated including: Determine whether the battery temperature is greater than a preset temperature; If so, the compensation voltage is calculated according to the static time, the equivalent circuit model and the model parameters; If not, the compensation voltage is calculated according to the rest time, the battery temperature, the preset temperature, the equivalent circuit model and the model parameters.

4. The method according to claim 3, characterized in that Calculating the compensation voltage based on the static time, equivalent circuit model and model parameters includes: When the equivalent circuit model is a second-order RC model, the formula for calculating the compensation voltage is Formula A1, which is: is the compensation voltage, V 1 is the first parameter, V 2 is the second parameter, t is the static time, R 1 is the electrochemical polarization internal resistance, C 1 is the electrochemical polarization capacitance, R 2 is the concentration difference polarization resistance, C 2 is the concentration difference polarization capacitance.

5. The method according to claim 3, characterized in that: Calculating the compensation voltage based on the static time, equivalent circuit model and model parameters includes: When the equivalent circuit model is the Thevenin model, the formula for calculating the compensation voltage is Formula A2, which is: is the compensation voltage, V 1 is the first parameter, t is the static time, R 1 is the electrochemical polarization internal resistance, C 1 is the electrochemical polarization capacitance.

6. The method according to claim 3, characterized in that Calculating the compensation voltage based on the static time, equivalent circuit model and model parameters includes: When the equivalent circuit model is the PNGV model, the formula for calculating the compensation voltage is Formula A3, which is: in, is the compensation voltage, V 1 is the first parameter, t is the static time, R 1 is the electrochemical polarization internal resistance, C 1 is the electrochemical polarization capacitance, V 3 is the third parameter.

7. The method according to claim 3, characterized in that Calculating the compensation voltage based on the static time, equivalent circuit model and model parameters includes: When the equivalent circuit model is the GNL model, the formula for calculating the compensation voltage is Formula A4, which is: in, is the compensation voltage, V 1 is the first parameter, V 2 is the second parameter, V 3 is the third parameter, t is the static time, R 1 is the electrochemical polarization internal resistance, C 1 is the electrochemical polarization capacitance, R 2 is the concentration difference polarization resistance, C 2 is the concentration difference polarization capacitance.

8. The method according to any one of claims 4 to 7, characterized in that: The formula for calculating the compensation voltage based on the static time, battery temperature, preset temperature, equivalent circuit model and model parameters is: in, is the compensation voltage when the battery temperature is not greater than the preset temperature, Kb is the temperature correction coefficient, M is the preset temperature, T is the battery temperature, It is the compensation voltage when the battery temperature is greater than the preset temperature.

9. The method according to claim 8, characterized in that The value of the first parameter is 0.02, the value of the second parameter is 0.16, and the value of the third parameter is 0.

01.

10. The method according to claim 1, characterized in that The steps of determining the initial SOC of the battery system according to the maximum SOC value and the minimum SOC value include: Get the terminal SOC of the battery system when it was last shut down; Determine whether the terminal SOC is within the range defined by the maximum SOC value and the minimum SOC value; If yes, the terminal SOC is determined as the initial SOC of the battery system; If not, when the terminal SOC is greater than the maximum SOC value, the maximum SOC value is determined as the initial SOC of the battery system; when the terminal SOC is less than the minimum SOC value, the minimum SOC value is determined as the initial SOC of the battery system.

11. The method according to claim 1, characterized in that: The steps of taking the first corrected voltage and the second corrected voltage as the open circuit voltage, querying the OCV-SOC table, and obtaining the maximum SOC value and the minimum SOC value include: The first corrected voltage and the second corrected voltage are respectively used as open circuit voltages, and the T-OCV-SOC table is queried according to the temperature of the battery system to obtain the maximum SOC value and the minimum SOC value.

12. A battery system, characterized in that: include: at least one processor; as well as A memory, wherein the memory is communicatively connected to at least one processor, and the memory stores instructions executable by at least one processor, and the instructions are executed by at least one processor so that the at least one processor can execute the method described in any one of claims 1 to 11.

13. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the processor executes the steps of the method according to any one of claims 1 to 11.

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