Battery pack SOC estimation method and device based on battery model dynamic interpolation

Abstract

The invention discloses a battery pack SOC estimation method based on battery model dynamic interpolation. The method comprises the following steps: acquiring an SOC-OCV curve of each single cell in a battery pack; based on an RC model, independently estimating the SOC of the single battery cells under the highest, average and lowest voltages; and comparing the SOC of the single cells under the highest, average and lowest voltages with an SOC-OCV curve to obtain the OCV of the single cells under the highest, average and lowest voltages. According to the main technical scheme and the main effects, the SOC of the battery cell and the battery pack can be accurately estimated by combining the real-time voltage of the single battery and the SOC-OCV curve dynamic look-up table based on a battery model dynamic interpolation technology. Compared with an SOC correction method depending on standing or constant-current working conditions in the prior art, the SOC correction method has the advantages that the problem of low efficiency caused by long-time standing waiting is avoided, the dynamic change of the battery can be reflected in real time, and SOC estimation with higher precision is provided.

Description

Technical Field

[0001] The present invention relates to the field of batteries, and particularly to a method and device for estimating the SOC of a battery pack based on dynamic interpolation of a battery model. Background Art

[0002] With the rapid development of new energy vehicles and grid energy storage technologies in recent years, as the core of new energy vehicles and grid energy storage - power batteries and energy storage batteries, safe and efficient management is required to ensure the safety of operation and extend the service life of the batteries. The ratio of the remaining capacity of the battery after being used for a period of time or left unused for a long time to the capacity in its fully charged state is the SOC, which is usually expressed as a percentage and has a value range of 0 - 1. Accurate prediction of the battery SOC can prevent overcharging and over-discharging during the charging and discharging process of the battery, thereby ensuring the safe use of the battery and extending its service life. For high-voltage projects or energy storage projects, the number of battery cells is generally more than 100. For high-voltage energy storage, each cluster has more than 400 battery cells. Some customers require the output of the cell-level SOC value with a high accuracy within 5%. This requires the BMS to add a battery model correction function, which involves a large amount of calculation. It is relatively difficult to implement this function on a single MCU, which will affect the CPU load. Since the SOC-OCV curve is non-linear, the operation of other functions will be affected. Summary of the Invention

[0003] Object of the Invention: The object of the present invention is to solve the technical problems in the prior art and provide a method, device, equipment and medium for estimating the SOC of a battery pack based on dynamic interpolation of a battery model.

[0004] One or more embodiments of this specification simultaneously relate to a device for estimating the SOC of a battery pack based on dynamic interpolation of a battery model, an electronic device, a computer-readable storage medium, and a computer program product to solve the technical defects existing in the prior art.

[0005] Technical Solution:

[0006] In a first aspect, the present application proposes a method for estimating the SOC of a battery pack based on dynamic interpolation of a battery model, including the steps of:

[0007] Obtain the SOC-OCV curve of each single battery cell in the battery pack;

[0008] Estimate the SOC of the single battery cell at the highest, average, and lowest voltages respectively based on the RC model;

[0009] Compare the estimated SOC of the single battery cell at the highest, average, and lowest voltages with the SOC-OCV curve to obtain the OCV of the single battery cell at the highest, average, and lowest voltages;

[0010] The OCV values of the single cells at the highest, average, and lowest voltages are linearly interpolated to obtain the OCV values of the single cells;

[0011] The SOC of the single cell is obtained by comparing the OCV value of the single cell obtained by linear interpolation with the SOC-OCV curve;

[0012] The battery pack SOC is obtained by integrating the SOC values of the single cells.

[0013] Preferably, obtaining the SOC-OCV curve of each single cell in the battery pack includes:

[0014] Perform an OCV cell test on the single cell. Specifically, charge or discharge to the corresponding SOC, and then let it stand for 2 hours. The voltage at this time is the OCV at this SOC to obtain the SOC-OCV curve of the single cell.

[0015] Preferably, estimating the SOC of the single cell at the highest, average, and lowest voltages based on the RC model includes:

[0016] Obtain the polarization voltage of the single cell through the first-order differential equation of the RC model circuit;

[0017] Calculate the terminal voltage of the single cell through the polarization voltage;

[0018] According to the terminal voltage of the single cell, obtain the SOC of the single cell at the highest, average, and lowest voltages through the battery model formula.

[0019] Preferably, obtaining the polarization voltage of the single cell through the first-order differential equation of the RC model circuit includes the following formula:

[0020] ;

[0021] where i is the order of the RC model circuit, dt is the sampling interval time, Rp is the polarization resistance, C is the capacitance, and Vpi is the i-th order polarization voltage.

[0022] Preferably, calculating the terminal voltage of the single cell through the polarization voltage includes the following formula:

[0023] ;

[0024] where V t is the terminal voltage of the single cell, Vocv is the OCV voltage of the single cell, R0 is the ohmic resistance of the RC model circuit, Vp1 is the first-order polarization voltage, Vp2 is the second-order polarization voltage, and I is the current of the battery.

[0025] Preferably, the SOC of the single cell at the highest, average, and lowest voltages is obtained through the battery model formula based on the end voltage of the single cell, including the following formula:

[0026] ;

[0027] ;

[0028] Among them, SOC(t) is the SOC of the single cell at time t, kp is the correction coefficient, Vcell is the sampled single cell voltage, SOC(t - 1) is the SOC of the single cell at time t - 1, and the initial value can be preset according to requirements;

[0029] The SOC of the single cell at the highest, average, and lowest voltages is obtained by substituting the sampled single cell voltages of the single cell at the highest, average, and lowest voltages into the formula.

[0030] Preferably, the OCV of the single cell at the highest, average, and lowest voltages is linearly interpolated to obtain the OCV value of the single cell, including:

[0031] ;

[0032] Among them, OcvMax, OcvAvg, and OcvMin are the OCVs of the single cell at the highest, average, and lowest voltages respectively;

[0033] VcellMax, VcellAvg, and VcellMin are the sampled single cell voltages of the single cell at the highest, average, and lowest voltages respectively;

[0034] Vcell n is the sampled single cell voltage of the single cell, OcvCell n is the OCV value of the single cell corresponding to the sampled single cell, and n is the Vcell serial number of the single cell.

[0035] Preferably, the battery pack SOC is obtained by combining the SOC values of the single cells, including the following formula:

[0036] ;

[0037] Among them, PackSoc is the battery pack SOC, SocMin and SocMax are the OCVs of the single cell at the highest and lowest voltages respectively, CellSoc i is obtained by comparing the SOC-OCV curve of OcvCell n , n0 is the number of single cells, and i is the CellSoc serial number of the single cell.

[0038] Preferably, it further includes first-order filtering of the battery pack SOC, including:

[0039] ;

[0040] wherein, PackSoc(t) is the SOC of the battery pack at time t, PackSoc(t - 1) is the SOC of the battery pack at time t - 1, and k is a preset threshold.

[0041] In a second aspect, an embodiment of the present invention provides a battery pack SOC estimation device based on dynamic interpolation of a battery model, including:

[0042] An acquisition unit for acquiring the SOC-OCV curve of each single battery cell in the battery pack;

[0043] An operation unit for respectively estimating the SOC of the single battery cell at the highest, average, and lowest voltages based on the RC model;

[0044] A matching unit for comparing the SOC of the single battery cell estimated at the highest, average, and lowest voltages with the SOC-OCV curve to obtain the OCV of the single battery cell at the highest, average, and lowest voltages; obtaining the SOC of the single battery cell by linearly interpolating the OCV value of the single battery cell against the SOC-OCV curve;

[0045] An interpolation unit for linearly interpolating the OCV of the single battery cell at the highest, average, and lowest voltages to obtain the OCV value of the single battery cell;

[0046] An integration unit for integrating the SOC values of the single battery cells to obtain the battery pack SOC.

[0047] In a third aspect, an embodiment of the present invention provides an electronic device, including a processor and a memory. Among them, the memory is used to store one or more computer programs; when the one or more computer programs stored in the memory are executed by the processor, the electronic device can implement the method of any possible design in the first aspect above.

[0048] In a fourth aspect, the present invention provides a computer-readable storage medium, in which a computer program is stored, and when the computer program is executed by a processor, the method described in any one of the above embodiments is implemented.

[0049] In a fifth aspect, an embodiment of the present invention further provides a computer program product, and when the computer program product runs on an electronic device, the electronic device is caused to execute the method of any possible design in any one of the above aspects.

[0050] Beneficial effects: Based on the battery model dynamic interpolation technology, combined with the real-time voltage of the single battery and the dynamic look-up table of the SOC-OCV curve, it can accurately estimate the SOC of the battery cell and the battery pack. Compared with the existing SOC correction methods that rely on static or constant current working conditions, the present invention not only avoids the low efficiency problem of long-term static waiting, but also can reflect the dynamic changes of the battery in real time, providing a higher-precision SOC estimation;

[0051] The static SOC correction methods in the prior art often cannot meet complex application scenarios (such as high-voltage energy storage systems). However, through dynamic interpolation and real-time correction of the battery model in the present invention, it can adapt to different charge and discharge working conditions. Especially in the actual application where the battery current and voltage change dynamically, it can reflect the change of SOC in real time and accurately, enhancing the real-time response ability of the system;

[0052] Since the present invention can estimate the SOC at the battery cell level and the battery pack SOC simultaneously, it is particularly applicable to application scenarios such as high-voltage energy storage systems and electric vehicles. For the case where there are many battery cells in the battery pack, the present invention can still provide a high-precision SOC estimation, meeting the requirements of large-scale battery management systems.

[0053] Through the real-time correction and dynamic interpolation methods provided by the present invention, the battery management system can respond more timely to the changes in the battery state, avoid overcharging, over-discharging or battery damage caused by inaccurate SOC estimation, thereby improving the overall stability of the system and the service life of the battery. Brief Description of the Drawings

[0054] Figure 1 It is a schematic diagram of the method framework provided by the present invention;

[0055] Figure 2 It is the RC model circuit diagram provided by the present invention;

[0056] Figure 3 It is a schematic diagram of the SOC-OCV curve provided by the present invention;

[0057] Figure 4 It is a schematic diagram of the SOC simulation provided by the present invention;

[0058] Figure 5 It is a schematic diagram of the structure of the device provided by an embodiment of the present application;

[0059] Figure 6 It is a block diagram of the structure of an electronic device provided by an embodiment of the present application. Detailed Embodiments

[0060] To make the technical solution of the present invention clearer, the following further describes the present invention in detail with specific embodiments in conjunction with the accompanying drawings.

[0061] Embodiment 1

[0062] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein shall have the ordinary meanings understood by those of ordinary skill in the art to which the present invention pertains. The words such as "including" used herein mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects.

[0063] The English and Chinese translations mentioned in this application are as follows:

[0064] BMS: Battery Management System, battery management system;

[0065] SOC: State of Charge, state of charge of the battery;

[0066] SOH: State of Health, state of health of the battery;

[0067] OCV: Open Circuit Voltage, open circuit voltage of the battery;

[0068] MCU: Microcontroller Unit, microcontroller unit, also known as a single-chip microcomputer;

[0069] CPU: Central Processing Unit, central processing unit;

[0070] HPPC: Hybrid Pulse Power Characterization, hybrid pulse power characteristic;

[0071] The capacity test (capacity test) is a process for determining the actual capacity (Q) of the battery. The specific implementation steps are as follows: Charge the battery fully: First, charge the battery to a fully charged (100% SOC) state. Constant current discharge test: Under specified temperature conditions, continuously discharge the battery at a constant current (such as 1C or a specified standard current) until a specified cut-off voltage (such as 2.5V or 3.0V, depending on the battery type), and record the discharge capacity: Measure the total charge released by the battery during the discharge process through current integration, which is the actual capacity (Q) of the battery. Repeat the test and take the average: To improve the measurement accuracy, the test is usually repeated multiple times and the average value of the capacity measurement is taken.

[0072] Aiming at the problems existing in the prior art, such as Figure 1 and Figure 2 As shown, a method for estimating the SOC of a battery pack based on dynamic interpolation of a battery model includes the steps:

[0073] Step 1, obtain the SOC-OCV curve of each single cell in the battery pack;

[0074] In some preferred embodiments, obtaining the SOC-OCV curve of each single cell in the battery pack includes:

[0075] As Figure 3 shown, for the SOC-OCV curve of a single cell in some embodiments, perform an OCV cell test on the single cell. Among them, charge or discharge to the corresponding SOC, and then let it stand for 2 hours. At this time, the voltage during standing is the OCV at this SOC, so as to obtain the SOC-OCV curve of the single cell.

[0076] Step 2, respectively estimate the SOC of the single cell at the highest, average, and lowest voltages based on the RC model;

[0077] Step 3, compare the SOC of the single cell estimated at the highest, average, and lowest voltages with the SOC-OCV curve to obtain the OCV of the single cell at the highest, average, and lowest voltages;

[0078] Step 4, perform linear interpolation on the OCV of the single cell at the highest, average, and lowest voltages to obtain the OCV value of the single cell;

[0079] Step 5, compare the OCV value of the single cell obtained by linear interpolation with the SOC-OCV curve to obtain the SOC of the single cell;

[0080] Step 6, integrate the SOC values of the single cells to obtain the SOC of the battery pack.

[0081] In some preferred embodiments, respectively estimating the SOC of the single cell at the highest, average, and lowest voltages based on the RC model includes:

[0082] Obtain the polarization voltage of the single cell through the first-order differential equation of the RC model circuit;

[0083] Calculate the terminal voltage of the single cell through the polarization voltage;

[0084] According to the terminal voltage of the single cell, obtain the SOC of the single cell at the highest, average, and lowest voltages through the battery model formula.

[0085] In some preferred embodiments, the polarization voltage of a single battery cell is obtained from the first-order differential equation of an RC model circuit, including the following formula:

[0086] ;

[0087] where i is the order of the RC model circuit, dt is the sampling interval time, Rp is the polarization resistance, C is the capacitance, and Vpi is the i-th order polarization voltage.

[0088] As Figure 2 shown, for the second-order RC model circuit in some embodiments, if it is the third order, C3 and Rp3 need to be added, and so on. The higher the order, the higher the accuracy.

[0089] In some preferred embodiments, the terminal voltage of a single battery cell is calculated from the polarization voltage, including the following formula:

[0090] ;

[0091] where V t is the terminal voltage of the single battery cell, Vocv is the OCV voltage of the single battery cell. Vocv is the static voltage when the current is 0 and after a long standing time, generally more than 2 hours of standing time, and it is the voltage obtained through OCV testing. R0 is the ohmic resistance of the RC model circuit, Vp1 is the first-order polarization voltage, Vp2 is the second-order polarization voltage, and I is the current of the battery.

[0092] In some preferred embodiments, according to the terminal voltage of the single battery cell, the SOC of the single battery cell at the highest, average, and lowest voltages is obtained through the battery model formula, including the following formula:

[0093] ;

[0094] ;

[0095] where SOC(t) is the SOC of the single battery cell at time t, kp is the correction coefficient, Vcell is the sampled single battery voltage, which is the voltage of each battery cell obtained by BMS sampling, and then the highest voltage, the lowest voltage, and the average battery cell voltage are found by comparison; SOC(t - 1) is the SOC of the single battery cell at time t - 1, and the initial value can be preset according to requirements;

[0096] The SOC of the single battery cell at the highest, average, and lowest voltages is obtained by substituting the sampled single battery voltages of the single battery cell at the highest, average, and lowest voltages into the formula;

[0097] The battery model formula is the existing Thevenin formula, and the polarization voltage formula solved by the first-order differential of RC is also a conventional formula. SOC(t-1) refers to the SOC value at the previous moment, and the initial value can be calibrated when the product comes off the production line, such as 30%. This formula needs to be calculated iteratively at regular intervals, for example, once every 100 ms, and SOC will change with the changes in current I and dv.

[0098] In some preferred embodiments, the OCV of the single-cell battery at the highest, average, and lowest voltages is linearly interpolated to obtain the OCV value of the single-cell battery, including:

[0099] ;

[0100] Among them, OcvMax, OcvAvg, and OcvMin are the OCVs of the single-cell battery at the highest, average, and lowest voltages respectively;

[0101] VcellMax, VcellAvg, and VcellMin are the single-cell voltages of the single-cell battery at the sampled highest, average, and lowest voltages respectively;

[0102] Vcell n is the single-cell voltage of the single-cell battery obtained by sampling, and OcvCell n is the OCV value of the corresponding single-cell battery of the single-cell battery obtained by sampling, and n is the Vcell serial number of the single-cell battery.

[0103] In some preferred embodiments, the battery pack SOC is obtained by combining the SOC values of the single-cell batteries, including the following formula:

[0104] ;

[0105] Among them, PackSoc is the battery pack SOC, SocMin and SocMax are the OCVs of the single-cell battery at the highest and lowest voltages respectively, and CellSoc i is obtained by comparing the SOC-OCV curve of OcvCell n , n0 is the number of single-cell batteries, and i is the CellSoc serial number of the single-cell battery.

[0106] In some preferred embodiments, it also includes first-order filtering of the battery pack SOC, including:

[0107] ;

[0108] Among them, PackSoc(t) is the SOC of the battery pack at time t, PackSoc(t - 1) is the SOC of the battery pack at time t - 1, and k is a preset threshold. The purpose is to ensure that the change range of SOC is not too large because there are also errors in the SOC estimated by the battery model. In some embodiments, k can be 0.95.

[0109] In some preferred embodiments, in combination with Figure 4 , to verify the feasibility of the solution, the WLTP working condition of a certain 48V project is used for simulation. There are a total of 14 lithium iron phosphate battery cells. The voltage of one cell is artificially increased by 100 mV, and the voltage of another cell is decreased by 100 mV, while the others remain unchanged. The values of the corresponding cells can be estimated in real time, and filtering adjustment will also be performed to meet the accuracy requirements. Among them, the first curve Current refers to the current working condition of the battery, the second curve CellVol refers to the voltages of the 14 battery cells corresponding to the current working condition of the battery, the third curve CellSOC refers to the estimated SOC of the 14 battery cells, and the fourth curve PackSoc refers to the SOC of the battery pack.

[0110] In some embodiments, a battery pack SOC estimation device based on dynamic interpolation of a battery model is also proposed. In combination with Figure 5 , it includes:

[0111] An acquisition unit 301, configured to acquire the SOC-OCV curve of each single battery cell in the battery pack;

[0112] An operation unit 302, configured to estimate the SOC of the single battery cell at the highest, average, and lowest voltages respectively based on the RC model;

[0113] A matching unit 303, configured to compare the SOC of the single battery cell estimated at the highest, average, and lowest voltages with the SOC-OCV curve to obtain the OCV of the single battery cell at the highest, average, and lowest voltages; obtain the SOC of the single battery cell by linearly interpolating the OCV value of the single battery cell and comparing it with the SOC-OCV curve;

[0114] An interpolation unit 304, configured to perform linear interpolation on the OCV of the single battery cell at the highest, average, and lowest voltages to obtain the OCV value of the single battery cell;

[0115] An integration unit 305, configured to integrate the SOC values of the single battery cells to obtain the battery pack SOC.

[0116] All relevant contents of each step involved in the above method embodiment can be cited in the function description of the corresponding functional module, and will not be elaborated here.

[0117] In some other embodiments of the present invention, an electronic device 400 is disclosed in the embodiments of the present invention, such as Figure 6As shown, the electronic device may include: one or more processors 401; a memory 402; a display 403; one or more applications (not shown); and one or more computer programs 404. The above-mentioned devices may be connected through one or more communication buses 405. Wherein the one or more computer programs 404 are stored in the memory 402 and configured to be executed by the one or more processors 401. The one or more computer programs 404 include instructions, and the above instructions may be used to execute as Figures 1 to 4 each step in the corresponding embodiments.

[0118] Through the description of the above embodiments, those skilled in the art can clearly understand that for the convenience and brevity of description, only the above division of each functional module is used as an example. In practical applications, the above functions can be allocated to different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. The specific working processes of the systems, devices, and units described above can refer to the corresponding processes in the foregoing method embodiments and will not be repeated here.

[0119] In each embodiment of the present invention, each functional unit may be integrated in a processing unit, or each unit may exist physically alone, or two or more units may be integrated in one unit. The above integrated unit may be implemented in the form of hardware or in the form of a software functional unit.

[0120] If the above integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it may be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the embodiments of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, may be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) or a processor to execute all or part of the steps of the methods described in the embodiments of the present invention. The foregoing storage medium includes: various media such as flash memory, mobile hard disk, read-only memory, random access memory, magnetic disk, or optical disk that can store program codes.

[0121] The above is only the specific implementation manner of the embodiments of the present invention, but the protection scope of the embodiments of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed in the embodiments of the present invention should be covered by the protection scope of the embodiments of the present invention. Therefore, the protection scope of the embodiments of the present invention should be subject to the protection scope of the claims.

Claims

1. A battery pack SOC estimation method based on dynamic interpolation of a battery model, characterized in that: Includes steps: Obtain the SOC-OCV curve of each single cell in the battery pack; Estimate the single cell SOC at the highest, average and lowest voltages based on the RC model; Estimate the SOC of the single cell at the highest, average and lowest voltages against the SOC-OCV curve to obtain the OCV of the single cell at the highest, average and lowest voltages; The OCV value of a single cell is obtained by linearly interpolating the OCV of the single cell at the highest, average, and lowest voltages; The OCV value of the single cell is obtained by linear interpolation and the SOC of the single cell is obtained by comparing the SOC-OCV curve; The battery pack SOC is obtained by integrating the SOC values ​​of the individual cells.

2. A battery pack SOC calculation method based on dynamic interpolation of battery model according to claim 1, characterized in that: Obtaining the SOC-OCV curve of each single cell in the battery pack includes: The single cell is subjected to an OCV cell test, wherein the single cell is charged or discharged to a corresponding SOC and then left to stand for 2 hours, at which time the standing voltage is the OCV under the SOC, so as to obtain the SOC-OCV curve of the single cell.

3. The method for calculating the SOC of a battery pack based on dynamic interpolation of a battery model according to claim 1, characterized in that: Estimate the single cell SOC at the highest, average and lowest voltages based on the RC model, including: The polarization voltage of the single cell is obtained through the first-order differential equation of the RC model circuit; The end voltage of the single cell is obtained by calculating the polarization voltage; According to the end voltage of the single cell, the single cell SOC at the highest, average and lowest voltage is obtained through the battery model formula.

4. A battery pack SOC calculation method based on dynamic interpolation of battery model according to claim 3, characterized in that: The polarization voltage of the single cell is obtained by the first-order differential equation of the RC model circuit, including the following formula: ； Among them, i is the order of the RC model circuit, dt is the sampling interval, Rp is the polarization resistance, C is the capacitance, and Vpi is the i-th order polarization voltage.

5. A battery pack SOC calculation method based on dynamic interpolation of battery model according to claim 4, characterized in that: The end voltage of the single cell is calculated by polarization voltage, including the following formula: ； Among them, V t The end voltage of the single cell, Vocv is the OCV voltage of the single cell, R0 is the ohmic resistance of the RC model circuit, Vp1 is the first-order polarization voltage, Vp2 is the second-order polarization voltage, and I is the battery current.

6. A battery pack SOC calculation method based on dynamic interpolation of battery model according to claim 5, characterized in that: According to the end voltage of the single cell, the battery model formula is used to obtain the single cell SOC at the highest, average and lowest voltage, including the following formulas: ； ； Wherein, SOC(t) is the SOC of the single cell at time t, kp is the preset correction coefficient, Vcell is the sampled single cell voltage, SOC(t-1) is the SOC of the single cell at time t-1, the initial value can be preset according to demand, and Q is the battery capacity obtained through Capacity test; The single cell voltages of the single cells at the highest, average and lowest voltages are substituted into the formula to obtain the single cell SOCs at the highest, average and lowest voltages.

7. The method for calculating battery pack SOC based on dynamic interpolation of battery model according to claim 1, characterized in that: The OCV value of a single cell is obtained by linearly interpolating the OCV of the single cell at the highest, average, and lowest voltages, including: ； Among them, OcvMax, OcvAvg, and OcvMin are the OCV of the single cell at the highest, average, and lowest voltages respectively; VcellMax, VcellAvg, and VcellMin are the single cell voltages of the single cell at the highest, average, and lowest voltages sampled, respectively; Vcell n OcvCell is the single cell voltage of the sampled single cell. n is the OCV value of the single cell corresponding to the sampled single cell, and n is the Vcell number of the single cell.

8. The method for calculating battery pack SOC based on dynamic interpolation of battery model according to claim 1, characterized in that: The battery pack SOC is obtained by combining the SOC values ​​of the single cells, including the following formula: ； Among them, PackSoc is the battery pack SOC, SocMin and SocMax are the OCV of the single cell at the highest and lowest voltages respectively, and CellSoc i OcvCell n By comparing the SOC-OCV curve, n0 is the number of single cells, and i is the CellSoc number of the single cell.

9. The method for calculating battery pack SOC based on dynamic interpolation of battery model according to claim 1, characterized in that: It also includes first-order filtering of the battery pack SOC, including: ； Among them, PackSoc(t) is the SOC of the battery pack at time t, PackSoc(t-1) is the SOC of the battery pack at time t-1, and k is the preset threshold.

10. A battery pack SOC estimation device based on dynamic interpolation of a battery model, characterized in that: include: An acquisition unit, used to acquire the SOC-OCV curve of each single cell in the battery pack; A calculation unit, used to estimate the SOC of a single cell at the highest, average and lowest voltages based on an RC model; A matching unit is used to compare the estimated SOC of the single cell at the highest, average and lowest voltages with the SOC-OCV curve to obtain the OCV of the single cell at the highest, average and lowest voltages; the OCV value of the single cell is obtained by linear interpolation and compared with the SOC-OCV curve to obtain the SOC of the single cell; An interpolation unit is used to linearly interpolate the OCV of the single cell at the highest, average and lowest voltages to obtain the OCV value of the single cell; The integration unit is used to obtain the battery pack SOC by integrating the SOC values ​​of the single cells.

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