Lithium battery charge state determination method, product, equipment and medium

Abstract

The invention relates to the technical field of battery management, in particular to a lithium battery charge state determination method, a product, equipment and a medium. The method comprises the following steps: acquiring current, voltage and operating parameters of a battery in real time, wherein the operating parameters comprise SOH and temperature; inputting the current and the SOH into a state space model to obtain an SOC estimated value output by the state space model; determining equivalent circuit parameters corresponding to the SOC estimated value, the temperature and the current from a first mapping table; inputting the current and the equivalent circuit parameters into a state space model to obtain a voltage estimation value output by the state space model; and correcting the SOC estimation value based on the voltage and the voltage estimation value to obtain the corrected SOC of the battery. According to the invention, the accuracy of determining the state of charge of the lithium battery can be improved.

Description

Technical Field

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

[0002] With the widespread application of lithium batteries in various fields, it is particularly important to accurately estimate their state of charge (SOC). SOC is a key parameter that characterizes the remaining power of lithium batteries and is directly related to the battery's service life and safety. However, due to factors such as the nonlinear characteristics, temperature dependence, and aging of lithium batteries, accurately estimating SOC has always been a technical challenge.

[0003] Related technologies determine the battery SOC through the ampere-hour integration method, which measures the current of the battery during charging or discharging and then integrates the current to estimate the battery SOC. This method is simple, but is susceptible to current measurement errors, and the errors will accumulate over time, resulting in low accuracy of the obtained SOC. Summary of the invention

[0004] In order to solve the problem of low accuracy in determining SOC in the prior art, the present application provides a method, product, device and medium for determining the state of charge of a lithium battery.

[0005] In a first aspect, the present application provides a method for determining the state of charge of a lithium battery, which adopts the following technical solution: A method for determining a state of charge of a lithium battery, comprising: Acquire the current, voltage and operating parameters of the battery in real time, wherein the operating parameters include SOH and temperature; Inputting the current and the SOH into a state space model to obtain an estimated SOC value output by the state space model; determining equivalent circuit parameters corresponding to the estimated SOC value, the temperature and the current from a first mapping table; Inputting the current and the equivalent circuit parameters into the state-space model to obtain a voltage estimation value output by the state-space model; The SOC estimation value is corrected based on the voltage and the voltage estimation value to obtain a corrected SOC of the battery.

[0006] In a preferred example, the present application may be further configured as follows: the state space model includes a state equation; The step of inputting the current and the SOH into a state space model to obtain an estimated SOC value output by the state space model includes: Acquire an initial SOC estimation value, an initial SOH, and an initial current at a first acquisition moment, and input the initial SOC estimation value, the initial SOH, and the initial current into the state equation to obtain an SOC estimation value output by the state equation; for each acquisition moment after the first acquisition moment, repeat the SOC updating step to obtain an SOC estimation value at each acquisition moment; The SOC updating step includes: inputting the SOC estimation value at the last acquisition moment, the current and the SOH into the state equation to obtain the SOC estimation value.

[0007] In a preferred example, the present application may be further configured as follows: the state-space model further includes an output equation; The step of inputting the current and the equivalent circuit parameter into the state space model to obtain a voltage estimation value output by the state space model includes: For each collection moment after the first collection moment, repeatedly performing the voltage updating step to obtain a voltage estimation value at each collection moment; The voltage updating step includes: obtaining the last SOC estimation value output by the state equation at the last acquisition moment, determining the open circuit voltage corresponding to the last SOC estimation value from a second mapping table, inputting the open circuit voltage, the equivalent circuit parameters and the current into the output equation, and obtaining the voltage estimation value output by the output equation.

[0008] In a preferred example, the present application may be further configured as follows: the SOC estimation value is corrected based on the voltage and the voltage estimation value to obtain the corrected SOC of the battery, including: determining a correction value based on the current, the temperature, the voltage, and the voltage estimate; The sum of the estimated SOC value and the correction value is taken as the corrected SOC of the battery.

[0009] In a preferred example, the present application may be further configured as follows: determining the correction value based on the current, the temperature, the voltage and the voltage estimation value includes: determining a gain matrix based on the current and the temperature; calculating a voltage difference between the voltage and the voltage estimate; The product of the voltage difference and the gain matrix is ​​used as a correction value.

[0010] In a preferred example, the present application can be further configured as follows: the method further includes: Respectively obtaining voltage response data of the battery in each test of multiple tests under different test conditions; Extract equivalent circuit parameters based on the pulse current value and voltage response data corresponding to each test; The test conditions and equivalent circuit parameters corresponding to each test are stored as a mapping relationship, wherein the test conditions include ambient temperature, battery SOC and pulse current value; The mapping relationships corresponding to the multiple tests are constructed into the first mapping table.

[0011] In a preferred example, the present application can be further configured as follows: extracting equivalent circuit parameters based on pulse current and voltage response data corresponding to each test includes: Determining a fast voltage drop value and a slow voltage drop value from voltage response data corresponding to a target test, wherein the target test is any one of the multiple tests; determining an initial voltage of the battery when no pulse current is applied; Calculating the ratio of the rapid voltage drop value to the pulse current of the target test as the ohmic resistance; The voltage response data is fitted based on the initial voltage, the fast voltage drop value and the slow voltage drop value to obtain resistance parameters and impedance parameters; the ohmic resistance, the resistance parameters and the impedance parameters constitute equivalent circuit parameters of the target test.

[0012] In a second aspect, the present application provides a computer program product, which adopts the following technical solution: A computer program product comprises a computer program. When the computer program is executed by a processor, the method for determining the state of charge of a lithium battery as described in any one of the first aspects is implemented.

[0013] In a third aspect, the present application provides an electronic device, which adopts the following technical solution: one or more processors; Memory; At least one application, wherein the at least one application is stored in a memory and configured to be executed by at least one processor, and the at least one application is configured to: execute the method for determining the state of charge of a lithium battery as described in any one of the first aspects.

[0014] In a fourth aspect, the present application provides a computer-readable storage medium, which adopts the following technical solution: A computer-readable storage medium stores a computer program, which, when executed in a computer, causes the computer to execute the method for determining the state of charge of a lithium battery as described in any one of the first aspects.

[0015] In summary, this application includes the following beneficial technical effects: The present application provides a comprehensive data basis for subsequent SOC estimation by acquiring the battery's current, voltage, and operating parameters including SOH and temperature in real time, estimates the SOC and voltage based on the acquired parameters, and corrects the preliminary SOC estimate by comparing the actual voltage with the voltage estimate output by the model, thereby obtaining a more accurate battery SOC. Based on the state-space model and feedback control system, the computational complexity is relatively low, and it is suitable for implementation in resource-constrained embedded systems. Observation is based on a mathematical model. Even when there is a certain deviation between the battery model and the actual situation, the observer can still gradually correct the SOC estimation result through the feedback mechanism to ensure the robustness of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a flow chart of a method for determining the state of charge of a lithium battery provided in an embodiment of the present application; Figure 2 is a schematic diagram of an equivalent circuit provided in an embodiment of the present application; Figure 3 It is a structural schematic diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0017] The following is combined with Figure 1 -Attached Figure 3 This application is described in further detail.

[0018] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

[0019] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0020] In addition, the term "and / or" in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article, unless otherwise specified, generally means that the associated objects before and after are in an "or" relationship.

[0021] It should be noted that in the optional embodiments of the present application, the object information and other related data involved, when the embodiments in the present application are applied to specific products or technologies, need to obtain the permission or consent of the object, and the collection, use and processing of the relevant data need to comply with the relevant laws, regulations and standards of the relevant countries and regions. In other words, if the embodiments of the present application involve data related to the object, it needs to be obtained with the authorization and consent of the object, the authorization and consent of the relevant departments, and in compliance with the relevant laws, regulations and standards of the country and region. If personal information is involved in the embodiments, the acquisition of all personal information needs to obtain the consent of the individual. If sensitive information is involved, the separate consent of the information subject needs to be obtained. The embodiments also need to be implemented with the authorization and consent of the object.

[0022] The present application embodiment provides a method for determining the state of charge of a lithium battery, such as Figure 1 As shown, the method provided in the embodiment of the present application is performed by an electronic device, which can be a server or a terminal device, wherein the server can be an independent physical server, or a server cluster or distributed system composed of multiple physical servers, or a cloud server providing cloud computing services. The terminal device can be a smart phone, a tablet computer, a laptop computer, a desktop computer, etc., but is not limited thereto. The terminal device and the server can be directly or indirectly connected via wired or wireless communication, which is not limited in the embodiment of the present application. The method includes steps S101 to S105, wherein: S101. Acquire the current, voltage and operating parameters of the battery in real time. The operating parameters include SOH and temperature.

[0023] Specifically, the acquisition frequency can be pre-set. During the operation of the battery, the current, voltage and operating parameters of the battery are obtained according to the set acquisition frequency. The operating parameters include SOH (state of health) and temperature. Among them, SOH can be determined by calculating the ratio of the number of cycles of the battery and the cycle life. Each time the battery completes a cycle, the number of cycles of the battery is increased by one, and the SOH of the battery is updated at the same time. The SOH of the battery can be stored in an electronic device. Each time the current, voltage and operating parameters of the battery are collected once according to the acquisition frequency, the SOC of the battery is updated once according to the lithium battery state of charge determination method provided in this embodiment.

[0024] S102 , inputting the current and SOH into a state space model to obtain an estimated SOC value output by the state space model.

[0025] Specifically, the state space model includes a state equation, and the state equation is used to output the SOC estimation value of the battery in real time. The first acquisition moment after the battery starts running is taken as the first acquisition moment, and the initial current, initial SOC estimation value and initial SOH at the first acquisition moment are obtained, and the initial current, initial SOC estimation value and initial SOH are input into the state equation, and the state equation outputs the SOC estimation value. When the second acquisition moment is reached, the current and SOH at the second acquisition moment are obtained, and the SOC estimation value at the first acquisition moment and the current and SOH at the second acquisition moment are input into the state equation to obtain the updated SOC estimation value. When the third acquisition moment is reached, the current and SOH at the third acquisition moment are obtained, and the SOC estimation value at the second acquisition moment and the current and SOC at the third acquisition moment are input into the state equation to obtain the updated SOC estimation value, and so on, the state equation outputs the SOC estimation value in real time.

[0026] S103 . Determine equivalent circuit parameters corresponding to the SOC estimation value, temperature, and current from a first mapping table.

[0027] Specifically, multiple test conditions are pre-set, a test is performed for each test condition, and the voltage response data of the battery under each test is obtained. The test conditions include applying a pulse current to the battery under a set ambient temperature and battery SOC. In any test, the equivalent circuit parameters are extracted based on the pulse current value and voltage response data corresponding to the test, and the test conditions and equivalent circuit parameters corresponding to each test are stored as a mapping message, and the mapping relationships corresponding to the multiple tests are constructed into a first mapping table.

[0028] After determining the SOC estimation value, temperature and current corresponding to the current moment, the equivalent circuit parameters corresponding to the SOC estimation value (corresponding to the battery SOC in the first mapping table), temperature (corresponding to the battery temperature in the first mapping table) and current (corresponding to the pulse current value in the first mapping table) are searched from the first mapping table as equivalent circuit parameters, wherein an interpolation method can be used to improve the mapping accuracy.

[0029] S104 , inputting the current and equivalent circuit parameters into the state space model to obtain a voltage estimation value output by the state space model.

[0030] Specifically, the state space model also includes an output equation, and for each acquisition moment after the first acquisition moment, the voltage update step is repeatedly executed to obtain a dynamically updated voltage estimate. The voltage update step includes obtaining a previous SOC estimate output by the state equation at the previous acquisition moment, determining an open circuit voltage corresponding to the previous SOC estimate from a second mapping table, inputting the obtained open circuit voltage, equivalent circuit parameters and current into the output equation, and the output equation outputs a voltage estimate.

[0031] S105 . Correct the estimated SOC value based on the voltage and the estimated voltage value to obtain a corrected SOC of the battery.

[0032] Specifically, a correction value is calculated according to the current, temperature, voltage and voltage estimation value, and the sum of the SOC estimation value and the correction value is used as the corrected SOC of the battery.

[0033] This embodiment acquires the battery current, voltage and operating parameters including SOH and temperature in real time, thereby providing a comprehensive data basis for subsequent SOC estimation, estimates the SOC and voltage based on the acquired parameters, and corrects the preliminary SOC estimate by comparing the actual voltage with the voltage estimate output by the model, thereby obtaining a more accurate battery SOC. Based on the state space model and feedback control system, the computational complexity is relatively low, and it is suitable for implementation in resource-constrained embedded systems. Observation is based on a mathematical model. Even when there is a certain deviation between the battery model and the actual situation, the observer can still gradually correct the SOC estimation result through a feedback mechanism to ensure the robustness of the system.

[0034] In a possible implementation manner of the embodiment of the present application, the method further includes: Respectively obtain voltage response data of the battery in each test of multiple tests with different test conditions; Extract equivalent circuit parameters based on the pulse current value and voltage response data corresponding to each test; The test conditions and equivalent circuit parameters corresponding to each test are stored as a mapping relationship, and the test conditions include ambient temperature, battery SOC and pulse current value; The mapping relationships corresponding to the multiple tests are constructed into a first mapping table.

[0035] In this embodiment, the HPPC (Hybrid Pulse Power Characteristic) test method can be selected, and the test conditions include ambient temperature, battery SOC and pulse current value. The optional ambient temperatures include: -20°C, -10°C, 0°C, 25°C, 45°C, the optional battery SOCs include: 95%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, 5%, and the optional pulse current values ​​include: 0.3C, 0.5C, 1C. Any ambient temperature, any battery SOC and any pulse current value are combined into one test condition. After traversing various ambient temperatures, battery SOCs and pulse current values, multiple test conditions can be determined.

[0036] A test is performed under each test condition. The test process includes applying a series of current pulses to the battery, including a 10-second discharge, a 10-second charge, and a 40-second rest recovery process. The voltage response data during the test is collected. The voltage response data characterizes the voltage change during the test. The voltage change during the rest recovery period (40 seconds) is used to calculate parameters related to the slower time constant.

[0037] A possible implementation of the embodiment of the present application is to extract equivalent circuit parameters based on pulse current and voltage response data corresponding to each test, including: Determine a fast voltage drop value and a slow voltage drop value from voltage response data corresponding to a target test, the target test being any one of the multiple tests; Determine the initial voltage of the battery when no pulse current is applied; Calculate the ratio of the rapid voltage drop value and the pulse current of the target test as the ohmic resistance; The voltage response data is fitted based on the initial voltage, the fast voltage drop value and the slow voltage drop value to obtain the resistance parameters and the impedance parameters; the ohmic resistance, the resistance parameters and the impedance parameters constitute the equivalent circuit parameters of the target test.

[0038] In this embodiment, the voltage response data is a curve of voltage changing over time, and the voltage of the current when the circuit connection is completed but the pulse current is not applied is used as the initial voltage. The change rate threshold can be preset to divide the voltage change curve into a fast voltage drop stage, a first slow voltage drop stage, a second slow voltage drop stage and a voltage recovery stage in sequence. The change rate threshold includes a first change rate threshold that characterizes the boundary between the fast voltage drop stage and the first slow voltage drop stage, a second change rate threshold that characterizes the boundary between the first slow voltage drop stage and the second slow voltage drop stage, and the minimum value in the voltage change curve is the boundary between the second slow voltage drop stage and the voltage recovery stage. The first change rate threshold and the second change rate threshold can be set by technicians based on actual experience.

[0039] For the target test, the pulse current value in the test condition of the target test and the acquired voltage response data are imported into Matlab, and the voltage variation curve is fitted using the nonlinear least squares method or the signal processing toolbox to extract the required equivalent circuit parameters.

[0040] Specifically, the voltage change value corresponding to the fast voltage drop stage in the voltage response data of the target test is recorded as the fast voltage drop value, the slow voltage drop value includes the first slow voltage drop value and the second slow voltage drop value, the voltage change value of the first slow voltage drop stage is recorded as the first slow voltage drop value, and the voltage change value of the second slow voltage drop stage is recorded as the second slow voltage drop value. Figure 2, which shows an equivalent circuit schematic diagram, E(OCV)-SOC represents the open circuit voltage (OCV), which depends on the state of charge SOC; R Ohmic Characterizes ohmic resistance; R BV Characterize Butler-Volmer resistance; R WB1 and R WB2 Characterizes Warburg impedance. Equivalent circuit parameters include: Ohmic resistance R Ohmic 、Resistance parameters (R BV , C BV ), impedance parameters (R WB1 , C WB1 , R WB2 , C WB2 ).

[0041] At the moment the pulse discharge starts, measure the instantaneous drop in voltage V0 and calculate the ohmic resistance R by the formula Ohmic : Where ΔI is the amplitude of the applied pulse current, ΔV 快 is the rapid pressure drop value.

[0042] Through nonlinear fitting, the resistance parameters are obtained, and the formula is: Where t is time, V(t) is the voltage value in the voltage response data at time t, V0 is the initial voltage, ΔV 快 is the rapid pressure drop value.

[0043] Extract the resistance parameters, the formula is: Where t is time, V(t) is the voltage value in the voltage response data at time t, V0 is the initial voltage, ΔV 慢1 is the first slow voltage drop value, ΔV 慢2 is the second slow pressure drop value.

[0044] In a possible implementation manner of the embodiment of the present application, the state space model includes a state equation; Input the current and SOH into the state-space model to obtain the estimated SOC value output by the state-space model, including: Obtaining an initial SOC estimation value, an initial SOH, and an initial current at a first acquisition moment, and inputting the initial SOC estimation value, the initial SOH, and the initial current into a state equation to obtain an SOC estimation value output by the state equation; For each collection moment after the first collection moment, repeatedly performing the SOC updating step to obtain an estimated SOC value at each collection moment; The SOC updating step includes: inputting the SOC estimation value, current and SOH at the last acquisition moment into the state equation to obtain the SOC estimation value.

[0045] In this embodiment, a Lumberg state observer can be set to dynamically calculate the battery SOC, including two stages: establishing a state space model of the battery and designing an observer. This process is based on the battery model and estimates the internal state of the battery, including the SOC, through the observer. The battery can be modeled as a linear system through the state space model, and the SOC is regarded as one of the state variables of the system. The equivalent circuit model of the battery is often used for SOC estimation.

[0046] The second mapping table is the correspondence between the SOC and the open circuit voltage of the battery, which can be obtained in advance through experimental measurements. Before the battery is operated, the initial open circuit voltage and initial SOH of the battery are determined. The initial open circuit voltage can be determined by direct measurement, static measurement, and dynamic measurement. The initial SOH can be determined by calculating the ratio of the number of cycles and the cycle life. The SOC corresponding to the initial open circuit voltage is determined from the second mapping table as the initial SOC estimate SOC1. The initial current at the first acquisition moment is I1, and I0 is recorded as 0. Substitute it into the state equation to obtain the SOC estimate.

[0047] The state equation is: Among them, k represents the current calculation step, that is, the current acquisition time; d t represents the sampling time (the time difference between two adjacent acquisition moments), which can be calculated by 1 / acquisition frequency; C p It indicates the initial capacity of the battery, which can be determined from the factory configuration information of the battery; SOH indicates the SOH determined dynamically in the calculation step; I k-1 Indicates the current at the last acquisition moment; I k is the current at the current acquisition moment; tau is the time constant, which can be set manually according to actual experience.

[0048] In a possible implementation manner of the embodiment of the present application, the state space model further includes an output equation; Inputting the current and the equivalent circuit parameters into the state space model to obtain the voltage estimation value output by the state space model, including: for each acquisition moment after the first acquisition moment, repeatedly executing the voltage updating step to obtain the voltage estimation value at each acquisition moment; The voltage updating step includes: obtaining the last SOC estimation value output by the state equation at the last acquisition moment, determining the open circuit voltage corresponding to the last SOC estimation value from the second mapping table, inputting the open circuit voltage, equivalent circuit parameters and current into the output equation, and obtaining the voltage estimation value output by the output equation.

[0049] The output equation is: in, is the voltage estimate, OCV SOC(k-1) is the open circuit voltage.

[0050] A possible implementation of the embodiment of the present application is to correct the SOC estimate value based on the voltage and the voltage estimate value to obtain the corrected SOC of the battery, including: determining a correction value based on the current, the temperature, the voltage, and the voltage estimate; The sum of the estimated SOC value and the corrected value is taken as the corrected SOC of the lower battery.

[0051] The core idea of ​​the Lumberg state observer is to use the known battery model and output measurement values ​​to estimate the state value through feedback correction. After multiple iterations, the Lumberg state observer will gradually converge and provide an estimate that gradually approaches the actual SOC. Finally, the system outputs the battery SOC estimate As the current SOC of the battery.

[0052] The observer equation is: in, is the corrected SOC; is the SOC in the state equation k ; u(t) is the state equation is the correction value, which is used to adjust the state estimation by the difference between the measured value and the estimated value; L is the gain matrix, which determines the convergence speed of the observer; y(t) is the voltage; is the estimated voltage value; A and B are custom coefficients.

[0053] A possible implementation of the embodiment of the present application is to determine the correction value based on the current, temperature, voltage and voltage estimation value, including: determining a gain matrix based on current and temperature; Calculate the voltage difference between the voltage and the voltage estimate; The product of the voltage difference and the gain matrix is ​​taken as the correction value.

[0054] The gain matrix is: L(I,T,BalSts)=α·|I|·(1+β·(T-T0) 2 )·exp(-γ·BalSts) Among them, I is the current; α, β, γ are custom adjustment coefficients; T is temperature; T0 is the reference temperature of 25°C; BalSts is the equilibrium state. The larger the absolute value of the current I, the larger the gain L; the more the temperature T deviates from the reference temperature T0, the larger the gain L; the larger the equilibrium state BalSts, the smaller the gain L. Selecting an appropriate observer gain L is crucial to the stability and estimation accuracy of the system. It is generally determined by analyzing the actual working state of the battery. Under the working conditions where the mathematical model is accurate, the value of the gain L is too large, and under the working conditions where the data model is inaccurate, the value of the gain L is too small.

[0055] The embodiment of the present application provides a computer program product, including a computer program. When the computer program is executed by a processor, the contents shown in the above-mentioned lithium battery charge state determination method embodiment are implemented.

[0056] An electronic device is provided in an embodiment of the present application, such as Figure 3 As shown, Figure 3 The electronic device 300 shown includes: a processor 301 and a memory 303. The processor 301 and the memory 303 are connected, such as through a bus 302. Optionally, the electronic device 300 may also include a transceiver 304. It should be noted that in actual applications, the transceiver 304 is not limited to one, and the structure of the electronic device 300 does not constitute a limitation on the embodiments of the present application.

[0057] Processor 301 may be a CPU (Central Processing Unit), a general purpose processor, a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. It may implement or execute various exemplary logic blocks, modules and circuits described in conjunction with the disclosure of this application. Processor 301 may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, etc.

[0058] The bus 302 may include a path to transmit information between the above components. The bus 302 may be a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus. The bus 302 may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 3 Only one thick line is used in the diagram, but it does not mean that there is only one bus or only one type of bus.

[0059] The memory 303 can be a ROM (Read Only Memory) or other types of static storage devices that can store static information and instructions, a RAM (Random Access Memory) or other types of dynamic storage devices that can store information and instructions, or an EEPROM (Electrically Erasable Programmable Read Only Memory), a CD-ROM (Compact Disc Read Only Memory) or other optical disk storage, optical disk storage (including compressed optical disk, laser disk, optical disk, digital versatile disk, Blu-ray disk, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited to these.

[0060] The memory 303 is used to store the application code for executing the solution of the present application, and the execution is controlled by the processor 301. The processor 301 is used to execute the application code stored in the memory 303 to implement the contents shown in the above-mentioned lithium battery charge state determination method embodiment.

[0061] Figure 3 The electronic device shown is merely an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0062] An embodiment of the present application provides a computer-readable storage medium, on which a computer program is stored. When the computer-readable storage medium is run on a computer, the computer can execute the contents shown in the aforementioned lithium battery charge state determination method embodiment.

[0063] It should be understood that, although the steps in the flowchart of the accompanying drawings are displayed in sequence as indicated by the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least a part of the steps in the flowchart of the accompanying drawings may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily executed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be executed in turn or alternately with other steps or at least a part of the sub-steps or stages of other steps.

[0064] The above are only some implementation methods of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A method for determining the state of charge of a lithium battery, characterized in that: include: Acquire the current, voltage and operating parameters of the battery in real time, wherein the operating parameters include SOH and temperature; Inputting the current and the SOH into a state space model to obtain an estimated SOC value output by the state space model; Determine, from a first mapping table, equivalent circuit parameters corresponding to the estimated SOC value, the temperature, and the current; Inputting the current and the equivalent circuit parameters into the state-space model to obtain a voltage estimation value output by the state-space model; The SOC estimation value is corrected based on the voltage and the voltage estimation value to obtain a corrected SOC of the battery.

2. The method for determining the state of charge of a lithium battery according to claim 1, characterized in that: The state-space model includes state equations; The step of inputting the current and the SOH into a state space model to obtain an estimated SOC value output by the state space model includes: Acquire an initial SOC estimation value, an initial SOH, and an initial current at a first acquisition moment, and input the initial SOC estimation value, the initial SOH, and the initial current into the state equation to obtain an SOC estimation value output by the state equation; For each collection moment after the first collection moment, repeatedly performing the SOC updating step to obtain an estimated SOC value at each collection moment; The SOC updating step includes: inputting the SOC estimation value at the last acquisition moment, the current and the SOH into the state equation to obtain the SOC estimation value.

3. The method for determining the state of charge of a lithium battery according to claim 2, characterized in that: The state-space model also includes an output equation; The step of inputting the current and the equivalent circuit parameter into the state space model to obtain a voltage estimation value output by the state space model includes: For each collection moment after the first collection moment, repeatedly performing the voltage updating step to obtain a voltage estimation value at each collection moment; The voltage updating step includes: obtaining the last SOC estimation value output by the state equation at the last acquisition moment, determining the open circuit voltage corresponding to the last SOC estimation value from a second mapping table, inputting the open circuit voltage, the equivalent circuit parameters and the current into the output equation, and obtaining the voltage estimation value output by the output equation.

4. The method for determining the state of charge of a lithium battery according to claim 1, characterized in that: The step of correcting the estimated SOC value based on the voltage and the estimated voltage value to obtain a corrected SOC of the battery includes: determining a correction value based on the current, the temperature, the voltage, and the voltage estimate; The sum of the estimated SOC value and the correction value is taken as the corrected SOC of the battery.

5. The method for determining the state of charge of a lithium battery according to claim 4, characterized in that: The determining of the correction value based on the current, the temperature, the voltage and the voltage estimation value comprises: determining a gain matrix based on the current and the temperature; calculating a voltage difference between the voltage and the voltage estimate; The product of the voltage difference and the gain matrix is ​​used as a correction value.

6. The method for determining the state of charge of a lithium battery according to claim 1, characterized in that: The method further comprises: Respectively obtaining voltage response data of the battery in each test of multiple tests under different test conditions; Extract equivalent circuit parameters based on the pulse current value and voltage response data corresponding to each test; The test conditions and equivalent circuit parameters corresponding to each test are stored as a mapping relationship, wherein the test conditions include ambient temperature, battery SOC and pulse current value; The mapping relationships corresponding to the multiple tests are constructed into the first mapping table.

7. The method for determining the state of charge of a lithium battery according to claim 6, characterized in that: The extracting equivalent circuit parameters based on the pulse current and voltage response data corresponding to each test includes: Determining a fast voltage drop value and a slow voltage drop value from voltage response data corresponding to a target test, wherein the target test is any one of the multiple tests; determining an initial voltage of the battery when no pulse current is applied; Calculating the ratio of the rapid voltage drop value to the pulse current of the target test as the ohmic resistance; The voltage response data is fitted based on the initial voltage, the fast voltage drop value and the slow voltage drop value to obtain resistance parameters and impedance parameters; the ohmic resistance, the resistance parameters and the impedance parameters constitute equivalent circuit parameters of the target test.

8. A computer program product, characterized in that The method comprises a computer program, which, when executed by a processor, implements the steps of the method for determining the state of charge of a lithium battery according to any one of claims 1 to 7.

9. An electronic device, characterized in that: include: at least one processor; Memory; At least one application, wherein the at least one application is stored in a memory and configured to be executed by at least one processor, and the at least one application is configured to: execute the method for determining the state of charge of a lithium battery as described in any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed in a computer, the computer is caused to execute the method for determining the state of charge of a lithium battery according to any one of claims 1 to 7.

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