SOC-OCV curve calibration method and apparatus for battery pack, device, medium, and product

Abstract

An SOC-OCV curve calibration method and apparatus for a battery pack, a device, a medium, and a product. The method comprises: acquiring first mapping relationships respectively corresponding to a plurality of first SOCs of a battery pack under a first number of cycles (S110), wherein a first mapping relationship represents the correspondence between a standing duration after the battery pack is charged and discharged to a first SOC and an OCV; for each first SOC, on the basis of a first mapping relationship corresponding to the first SOC, determining an OCV corresponding to a first standing duration as a first OCV corresponding to the first SOC (S120), wherein the first standing duration is not shorter than the shortest duration required for the OCV being stable when the battery pack is charged and discharged to the first SOC; and on the basis of the plurality of first SOCs and first OCVs respectively corresponding thereto, determining a first SOC-OCV curve corresponding to the battery pack under the first number of cycles (S130).

Description

Battery pack SOC-OCV curve calibration method, device, equipment, medium and product

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application 202310786070.3, filed on June 29, 2023, entitled “SOC-OCV curve calibration method, device, equipment, medium and product for battery pack,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the field of batteries, and in particular to a method, device, equipment, medium and product for calibrating the SOC-OCV curve of a battery pack. Background Art

[0004] The state of charge (SOC)-open circuit voltage (OCV) curve is an important performance indicator of a battery pack.

[0005] In the prior art, when calibrating the SOC-OCV curve of a battery pack, the SOC-OCV curve of the battery pack is usually calibrated at different temperatures.

[0006] Summary of the Invention

[0007] The present application provides a method, device, equipment, medium and product for calibrating the SOC-OCV curve of a battery pack, which can at least solve the problem in the prior art that the SOC-OCV curve of a battery pack cannot be calibrated quickly and accurately.

[0008] In a first aspect, the present application provides a method for calibrating the SOC-OCV curve of a battery pack, the method comprising: obtaining first mapping relationships corresponding to multiple first SOCs of the battery pack at a first cycle number, the first mapping relationship representing the correspondence between the rest time and the OCV of the battery pack after charging and discharging to the first SOC; for each first SOC, according to the first mapping relationship corresponding to the first SOC, determining the OCV corresponding to the first rest time as the first OCV corresponding to the first SOC, the first rest time being not less than the shortest time required for the OCV of the battery pack to reach stability when charging and discharging to the first SOC; based on multiple first SOCs and their corresponding first OCVs, determining the first SOC-OCV curve corresponding to the battery pack at the first cycle number.

[0009] The SOC-OCV curve calibration method for a battery pack provided in an embodiment of the present application can be calibrated for a first cycle number to determine a first SOC-OCV curve corresponding to the battery pack at the first cycle number. This takes into account the impact of battery pack cycle aging on the SOC-OCV curve, thereby improving the accuracy of the SOC-OCV curve. In addition, in the process of calibrating the first SOC-OCV curve corresponding to the first cycle number based on multiple first SOCs and their corresponding first OCVs, the first OCV corresponding to each first SOC can be determined by the correspondence between the rest time and OCV after the battery pack is charged and discharged to the first SOC at the first cycle number (i.e., a first mapping relationship). The OCV corresponding to the first rest time in the first mapping relationship can be used as the first OCV corresponding to the first SOC. The first rest time is not less than the shortest time required for the OCV of the battery pack to reach stability when charging and discharging to the first SOC. In other words, during the calibration process, the battery pack does not need to actually rest for the first time when charging and discharging to the first SOC, thereby accelerating the calibration process. In this way, the SOC-OCV curve of the battery pack can be calibrated quickly and accurately.

[0010] In some embodiments, the above-mentioned acquisition of the first mapping relationships corresponding to multiple first SOCs of the battery pack under the first number of cycles includes: for each first SOC of the multiple first SOCs, performing the following steps respectively to obtain the first mapping relationships corresponding to the multiple first SOCs respectively: controlling the battery pack to stand still for a first preset time after charging and discharging to the first SOC, the first preset time being less than the shortest time required for the OCV of the battery pack to reach stability when charging and discharging to the first SOC; while the battery pack stands still for the first preset time, obtaining the second OCV of the battery pack when it stands still for multiple different time periods; determining the first mapping relationship corresponding to the first SOC based on the multiple different time periods and their corresponding second OCVs.

[0011] The SOC-OCV curve calibration method of a battery pack provided in an embodiment of the present application can calibrate the correspondence between the resting time and the OCV by resting for a first preset time, so as to subsequently determine the OCV corresponding to the first resting time based on the correspondence between the resting time and the OCV. Since the first preset time is less than the shortest time required for the OCV to reach stability when the battery pack is charged and discharged to the first SOC, and the resting time is not less than the shortest time required for the OCV to reach stability when the battery pack is charged and discharged to the first SOC, the OCV corresponding to the longer resting time can be obtained by resting for a shorter time, thereby improving the calibration efficiency of the SOC-OCV curve.

[0012] In some embodiments, the above-mentioned first cycle number is greater than a preset cycle number, and a first mapping relationship corresponding to the first SOC is determined based on multiple different time lengths and their corresponding second OCVs, including: obtaining a second mapping relationship corresponding to the first SOC of the battery pack when the battery cycle number is not greater than the preset cycle number, the second mapping relationship representing the correspondence between the standing time and OCV of the battery pack after charging and discharging to the first SOC; using the first fitting coefficient corresponding to the second mapping relationship as the initial value of the fitting coefficient, fitting multiple different time lengths and their corresponding second OCVs to obtain the first mapping relationship.

[0013] The SOC-OCV curve calibration method for a battery pack provided in an embodiment of the present application uses the first fitting coefficient of the second mapping relationship corresponding to a smaller number of cycles as the initial value of the fitting coefficient, and fits the first mapping relationship corresponding to a larger number of cycles, which can improve the fitting speed and accuracy.

[0014] In some embodiments, the above-mentioned fitting of multiple different time lengths and their corresponding second OCVs to obtain a first mapping relationship includes: obtaining a preset coefficient range corresponding to the fitting coefficient in the first mapping relationship; based on the preset coefficient range, fitting multiple different time lengths and their corresponding second OCVs to obtain a second fitting coefficient; and determining the first mapping relationship according to the second fitting coefficient.

[0015] The SOC-OCV curve calibration method for a battery pack provided in an embodiment of the present application can improve the fitting accuracy of the first mapping relationship by setting a preset coefficient range corresponding to the fitting coefficient in the first mapping relationship and performing fitting based on the preset coefficient range.

[0016] In some embodiments, before determining the first SOC-OCV curve corresponding to the battery pack at the first number of cycles based on multiple first SOCs and their corresponding first OCVs, the method further includes: for each first OCV in the multiple first OCVs, performing the following steps respectively: obtaining the first temperature of the battery pack when it is continuously stationary for a first preset time after being charged and discharged to the first SOC, the temperature conversion coefficient corresponding to the first temperature, and the third OCV of the battery pack at a preset standard temperature; correcting the first OCV according to the first temperature, the temperature conversion coefficient and the third OCV to obtain a corrected first OCV; the above-mentioned determination of the first SOC-OCV curve corresponding to the battery pack at the first number of cycles based on multiple first SOCs and their corresponding first OCVs includes: determining the first SOC-OCV curve corresponding to the battery pack at the first number of cycles based on multiple first SOCs and their corresponding corrected first OCVs.

[0017] The SOC-OCV curve calibration method for a battery pack provided in an embodiment of the present application corrects the first OCV by using the first temperature of the battery pack when it is continuously stationary for a first preset time after being charged and discharged to a first SOC, the temperature conversion coefficient corresponding to the first temperature, and the third OCV of the battery pack at a preset standard temperature. The first OCV can be temperature compensated, thereby improving the accuracy of the calibrated SOC-OCV curve.

[0018] In some embodiments, obtaining the temperature conversion coefficient includes: obtaining the correspondence between the temperature of the battery pack and the SOC-OCV curve at the second cycle number; determining a second SOC-OCV curve corresponding to the first temperature and a third SOC-OCV curve corresponding to the preset standard temperature based on the correspondence between the temperature and the SOC-OCV curve; searching for a fourth OCV corresponding to the first SOC from the second SOC-OCV curve, and searching for a fifth OCV corresponding to the first SOC from the third SOC-OCV curve; and determining the temperature conversion coefficient based on the first temperature, the preset standard temperature, the fourth OCV, and the fifth OCV.

[0019] The SOC-OCV curve calibration method for a battery pack provided in an embodiment of the present application takes into account the influence of the number of battery cycles on the temperature conversion coefficient when calculating the temperature conversion coefficient, and is therefore more accurate.

[0020] In some embodiments, the first cycle number is greater than the preset cycle number, and the second cycle number is not greater than the preset cycle number. The above-mentioned acquisition of the correspondence between the temperature of the battery pack and the SOC-OCV curve at the second cycle number includes: at the second cycle number, for each of the multiple temperatures, performing the following steps respectively to obtain the SOC-OCV curves corresponding to the multiple temperatures: obtaining the OCV corresponding to the battery pack at multiple SOCs at the temperatures; and determining the SOC-OCV curve corresponding to the temperature based on the multiple SOCs and their corresponding OCVs.

[0021] In the SOC-OCV curve calibration method for a battery pack provided in an embodiment of the present application, the second cycle number is no greater than the preset cycle number, and the temperature conversion coefficient is determined based on the correspondence between the temperature and the SOC-OCV curve at a smaller cycle number, which can make the temperature conversion coefficient more accurate.

[0022] In some embodiments, the above-mentioned respectively obtaining the OCV corresponding to the battery pack at multiple SOCs includes: performing the following steps for each SOC in the multiple SOCs to obtain the OCV corresponding to the multiple SOCs: controlling the battery pack to stand still for a first standing time after charging and discharging to the SOC; when the battery pack stands still for the first standing time, collecting the OCV of the battery pack to obtain the OCV corresponding to the SOC.

[0023] The SOC-OCV curve calibration method for a battery pack provided in an embodiment of the present application is more accurate because the OCV corresponding to the SOC is collected when the resting time is the first resting time, and the first resting time is not less than the shortest time required for the OCV to reach stability when the battery pack is charged and discharged to the first SOC. Therefore, the OCV corresponding to the SOC is more accurate, and the correspondence between the calibrated temperature and the SOC-OCV curve is more accurate, and the temperature conversion coefficient calculated based on the correspondence between the temperature and the SOC-OCV curve is also more accurate.

[0024] In some embodiments, the method further includes: for each of the multiple SOCs at the first cycle number, performing the following steps respectively to obtain the DC internal resistance (DCR) corresponding to the multiple SOCs at the first cycle number: controlling the battery pack to stop charging and keep it at rest when charging to the SOC at the first cycle number; while the battery pack is at rest, obtaining the charging current of the battery pack, the sixth OCV when the battery pack stops charging, and the seventh OCV when the battery pack is at rest for a second preset time; and determining the DCR corresponding to the SOC of the battery pack at the first cycle number based on the sixth OCV, the seventh OCV, and the charging current.

[0025] The SOC-OCV curve calibration method for a battery pack provided in an embodiment of the present application takes into account the effect of cycle aging on DCR when determining the DCR corresponding to the SOC, thereby improving the accuracy of the DCR.

[0026] In some embodiments, the method further includes: obtaining a second SOC of the battery pack at a first cycle number; when the second SOC falls within a preset SOC range, obtaining an eighth OCV, a charging capacity, a third SOC when fully charged, and a first SOC-OCV curve corresponding to the first cycle number of the battery pack; searching for a fourth SOC corresponding to the eighth OCV from the first SOC-OCV curve; and determining a state of health (SOH) of the battery pack at the first cycle number based on the charging capacity, the third SOC, and the fourth SOC.

[0027] The SOC-OCV curve calibration method of a battery pack provided in an embodiment of the present application takes into account the effect of cycle aging on the SOH when determining the SOH of the battery pack, thereby improving the accuracy of the SOH.

[0028] In a second aspect, the present application provides an SOC-OCV curve calibration device for a battery pack, the device comprising: a first acquisition module for acquiring first mapping relationships corresponding to multiple first SOCs of the battery pack at a first cycle number, the first mapping relationship representing the correspondence between the rest time and OCV of the battery pack after charging and discharging to the first SOC; a first determination module for determining, for each first SOC, according to the first mapping relationship corresponding to the first SOC, the OCV corresponding to the first rest time as the first OCV corresponding to the first SOC, the first rest time being not less than the shortest time required for the OCV of the battery pack to reach stability when charging and discharging to the first SOC; a second determination module for determining the first SOC-OCV curve corresponding to the battery pack at the first cycle number based on multiple first SOCs and their respectively corresponding first OCVs.

[0029] The SOC-OCV curve calibration device for a battery pack provided in an embodiment of the present application can calibrate for a first cycle number and determine a first SOC-OCV curve corresponding to the battery pack at the first cycle number. This takes into account the impact of battery pack cycle aging on the SOC-OCV curve, thereby improving the accuracy of the SOC-OCV curve. In addition, in the process of calibrating the first SOC-OCV curve corresponding to the first cycle number based on multiple first SOCs and their corresponding first OCVs, the first OCV corresponding to each first SOC can be determined by the correspondence between the rest time and OCV after the battery pack is charged and discharged to the first SOC at the first cycle number (i.e., a first mapping relationship). The OCV corresponding to the first rest time in the first mapping relationship can be used as the first OCV corresponding to the first SOC. The first rest time is not less than the shortest time required for the OCV of the battery pack to reach stability when charging and discharging to the first SOC. That is, during the calibration process, the battery pack does not need to actually rest for the first time when charging and discharging to the first SOC, thereby accelerating the calibration speed. In this way, the SOC-OCV curve of the battery pack can be calibrated quickly and accurately.

[0030] In a third aspect, the present application provides an electronic device, the device comprising: a processor and a memory storing computer program instructions;

[0031] When the processor executes the computer program instructions, the SOC-OCV curve calibration method of the battery pack as shown in any one of the embodiments of the first aspect is implemented.

[0032] In a fourth aspect, the present application provides a computer storage medium having computer program instructions stored thereon, which, when executed by a processor, implements the SOC-OCV curve calibration method for a battery pack shown in any one of the embodiments of the first aspect.

[0033] In a fifth aspect, an embodiment of the present application provides a computer program product. When the instructions in the computer program product are executed by a processor of an electronic device, the electronic device executes the SOC-OCV curve calibration method for the battery pack shown in any one of the embodiments of the first aspect.

[0034] The SOC-OCV curve calibration method, device, equipment, medium, and product of the battery pack provided in the embodiments of the present application can be calibrated for a first cycle number to determine the first SOC-OCV curve corresponding to the battery pack at the first cycle number. This takes into account the impact of battery pack cycle aging on the SOC-OCV curve, thereby improving the accuracy of the SOC-OCV curve. In addition, in the process of calibrating the first SOC-OCV curve corresponding to the first cycle number based on multiple first SOCs and their corresponding first OCVs, the first OCV corresponding to each first SOC can be determined by the correspondence between the rest time and OCV after the battery pack is charged and discharged to the first SOC at the first cycle number (i.e., the first mapping relationship). The OCV corresponding to the first rest time in the first mapping relationship can be used as the first OCV corresponding to the first SOC. The first rest time is not less than the shortest time required for the OCV of the battery pack to reach stability when charging and discharging to the first SOC. That is, during the calibration process, the battery pack does not need to actually rest for the first time when charging and discharging to the first SOC, thereby faster calibration. In this way, the SOC-OCV curve of the battery pack can be calibrated quickly and accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The features, advantages and technical effects of exemplary embodiments of the present application will be described below with reference to the accompanying drawings.

[0036] FIG1 is a schematic flow chart of a method for calibrating an SOC-OCV curve of a battery pack according to an embodiment of the present application;

[0037] FIG2 is a schematic diagram of a curve showing changes in OCV over time according to an embodiment of the present application;

[0038] FIG3 is a schematic diagram of a curve showing changes in OCV with standing time according to an embodiment of the present application;

[0039] FIG4 is a schematic diagram of a second-order equivalent circuit model according to an embodiment of the present application;

[0040] FIG5 is a second schematic diagram of a curve showing changes in OCV with standing time according to an embodiment of the present application;

[0041] FIG6 is a schematic diagram of a curve showing changes in OCV with temperature according to an embodiment of the present application;

[0042] FIG7 is a second schematic diagram of a curve showing changes in OCV over time according to an embodiment of the present application;

[0043] FIG8 is a schematic structural diagram of a SOC-OCV curve calibration device for a battery pack according to an embodiment of the present application;

[0044] FIG9 is a schematic structural diagram of an electronic device according to an embodiment of the present application.

[0045] In the accompanying drawings, the drawings are not necessarily drawn to scale. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0047] It should be noted that, in this document, relational terms such as first and second, etc. are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0048] As mentioned in the background technology, the SOC-OCV curve is an important performance indicator of a battery pack.

[0049] In the prior art, when calibrating the SOC-OCV curve of a battery pack, the SOC-OCV curve of the battery pack is usually calibrated at different temperatures.

[0050] However, the actual SOC-OCV curve of the battery pack will change after cycle aging, and the existing technology does not take into account the impact of battery pack cycle aging on the SOC-OCV curve. Therefore, the accuracy of the SOC-OCV curve calibrated in the existing technology is low. How to quickly and accurately calibrate the SOC-OCV curve of the battery pack has become a technical problem that needs to be solved urgently.

[0051] The SOC-OCV curve calibration method, device, equipment, medium, and product of the battery pack provided in the embodiments of the present application can be calibrated for a first cycle number to determine the first SOC-OCV curve corresponding to the battery pack at the first cycle number. This takes into account the impact of battery pack cycle aging on the SOC-OCV curve, thereby improving the accuracy of the SOC-OCV curve. In addition, in the process of calibrating the first SOC-OCV curve corresponding to the first cycle number based on multiple first SOCs and their corresponding first OCVs, the first OCV corresponding to each first SOC can be determined by the correspondence between the rest time and OCV after the battery pack is charged and discharged to the first SOC at the first cycle number (i.e., the first mapping relationship). The OCV corresponding to the first rest time in the first mapping relationship can be used as the first OCV corresponding to the first SOC. The first rest time is not less than the shortest time required for the OCV of the battery pack to reach stability when charging and discharging to the first SOC. That is, during the calibration process, the battery pack does not need to actually rest for the first time when charging and discharging to the first SOC, thereby faster calibration. In this way, the SOC-OCV curve of the battery pack can be calibrated quickly and accurately.

[0052] First, the SOC-OCV curve calibration method of the battery pack provided in the embodiment of the present application is described in detail with reference to FIG1 .

[0053] FIG1 is a flow chart of a method for calibrating an SOC-OCV curve of a battery pack according to an embodiment of the present application. It should be noted that the SOC-OCV curve calibration method of the battery pack can be applied to a SOC-OCV curve calibration device for a battery pack. As shown in FIG1 , the SOC-OCV curve calibration method of the battery pack can include the following steps:

[0054] S110, obtaining first mapping relationships corresponding to a plurality of first SOCs of the battery pack at a first cycle number;

[0055] S120 , for each first SOC, determining, according to a first mapping relationship corresponding to the first SOC, an OCV corresponding to a first resting time as a first OCV corresponding to the first SOC;

[0056] S130 , based on a plurality of first SOCs and their respective corresponding first OCVs, determining a first SOC-OCV curve corresponding to the battery pack at a first cycle number.

[0057] Thus, the first SOC-OCV curve corresponding to the battery pack at the first cycle number can be calibrated, and the first SOC-OCV curve corresponding to the battery pack at the first cycle number can be determined. This takes into account the impact of battery pack cycle aging on the SOC-OCV curve, thereby improving the accuracy of the SOC-OCV curve. In addition, in the process of calibrating the first SOC-OCV curve corresponding to the first cycle number based on multiple first SOCs and their corresponding first OCVs, the first OCV corresponding to each first SOC can be determined by the correspondence between the rest time and OCV after the battery pack is charged and discharged to the first SOC at the first cycle number (that is, the first mapping relationship). The OCV corresponding to the first rest time in the first mapping relationship can be used as the first OCV corresponding to the first SOC. The first rest time is not less than the shortest time required for the OCV to reach stability when the battery pack is charged and discharged to the first SOC. That is, during the calibration process, the battery pack does not need the actual first rest time when charging and discharging to the first SOC, so the calibration speed is faster. In this way, the SOC-OCV curve of the battery pack can be calibrated quickly and accurately.

[0058] Regarding S110 , the first cycle number may be the cycle number of the SOC-OCV curve to be calibrated. Calibrating the SOC-OCV curve of the battery pack may essentially be calibrating the OCVs corresponding to multiple SOCs. The first SOC may be the SOC to be calibrated, for example, 0%, 5%, 10%, 15%, ..., 100%.

[0059] The first mapping relationship may represent the correspondence between the rest time of the battery pack after being charged or discharged to the first SOC and the OCV. For example, the first mapping relationship may be a function expression, curve, or table between the rest time of the battery pack after being charged or discharged to the first SOC and the OCV.

[0060] Specifically, the mapping relationships between the rest time and OCV corresponding to different SOCs of the battery pack at different cycle numbers can be pre-calibrated. Then, the mapping relationships between the rest time and OCV corresponding to different SOCs at a first cycle number can be searched first, and then the mapping relationships between the rest time and OCV corresponding to multiple first SOCs can be searched from the search results to obtain the first mapping relationships corresponding to the multiple first SOCs of the battery pack at the first cycle number.

[0061] In some implementations, to improve calibration efficiency, S110 may include:

[0062] For each of the multiple first SOCs, the following steps are performed respectively to obtain first mapping relationships corresponding to the multiple first SOCs:

[0063] Control the battery pack to continue to stand still for a first preset duration after charging and discharging to the first SOC;

[0064] During the process that the battery pack continues to stand still for the first preset duration, respectively obtain the second OCV of the battery pack when standing still for multiple different durations;

[0065] Determine the first mapping relationship corresponding to the first SOC according to multiple different durations and their respectively corresponding second OCVs.

[0066] Here, the first preset duration can be less than the shortest duration required for the OCV to reach stability when the battery pack is charged and discharged to the first SOC. Exemplarily, the shortest duration can be 2h, and the first preset duration can be t1 (1min < t < 5min).

[0067] Exemplarily, the battery pack can be controlled to discharge at a rate C1 (0.2C < C1 < 0.5C) until the SOC is equal to 100%, and then continue to stand still for a duration of t1 (1min < t1 < 5min). During the process of continuing to stand still for a duration of t1, respectively obtain the second OCV when standing still for multiple different durations (t1 - n, t1 - n + 1,..., t1 - 1, t1), and determine the first mapping relationship corresponding to the SOC equal to 100% based on multiple different durations and their respectively corresponding second OCVs; then, continue to control the battery pack to continue discharging until the SOC is equal to 95%, and then continue to stand still for a duration of t1 (1min < t1 < 5min), and during the process of continuing to stand still for a duration of t1, respectively obtain the second OCV when standing still for multiple different durations (t1 - n, t1 - n + 1,..., t1 - 1, t1), and determine the first mapping relationship corresponding to the SOC equal to 95% based on multiple different durations and their respectively corresponding second OCVs; repeat the above process to respectively determine the first mapping relationships corresponding to other values of the SOC until the SOC is equal to 0%.

[0068] In addition, a charging device can be used to charge the battery pack at a rate C1 (0.2C < C1 < 0.5C) until the SOC is equal to 0%, and then keep it static for a duration t1 (1 min < t1 < 5 min). During the process of keeping it static for the duration t1, the second OCVs at multiple different static durations (t1 - n, t1 - n + 1, …, t1 - 1, t1) are obtained respectively, and based on the multiple different durations and their corresponding second OCVs, the first mapping relationship corresponding to when the SOC is equal to 0% is determined; then, continue to charge the battery pack until the SOC is equal to 5%, then keep it static for the duration t1 (1 min < t1 < 5 min), and during the process of keeping it static for the duration t, the second OCVs at multiple different static durations (t1 - n, t1 - n + 1, …, t1 - 1, t1) are obtained respectively, and based on the multiple different durations and their corresponding second OCVs, the first mapping relationship corresponding to when the SOC is equal to 5% is determined; repeat the above process to determine the first mapping relationships corresponding to other SOC values until the constant voltage charging reaches 0.05C, that is, the SOC is equal to 100%.

[0069] Exemplarily, during the process of charging from the SOC equal to 0% to the SOC equal to 100%, the corresponding relationship between the OCV and time can be as shown in Figure 2. The relationship curve between the static duration and the OCV during each process of keeping it static for the duration t1 can be as shown in Figure 3.

[0070] Specifically, the following formula can be used to fit the relationship curve between the static duration and the OCV by the least squares method to obtain the fitting formula, that is, the first mapping relationship. After obtaining the fitting formula, the OCV at different static durations can be calculated.

[0071] The fitting formula can be:[[]]

[0072] where V(t) is the OCV and t is the static duration. This fitting formula can be based on the second-order equivalent circuit model as shown in Figure 4.

[0073] The expression formula for the static state after discharge can be:[[]]

[0074] where V ocv (SOC,T) is the OCV varying with temperature and SOC, V p1 (0) is the first-order polarization voltage at t = 0, V p2 (0) is the second-order polarization voltage at t = 0, τ1 is the first-order time constant, and τ is the second-order time constant.

[0075] In this way, the correspondence between the resting time and the OCV can be calibrated by standing for a first preset time, so that the OCV corresponding to the first resting time can be determined based on the correspondence between the resting time and the OCV. Since the first preset time is less than the shortest time required for the OCV to reach stability when the battery pack is charged and discharged to the first SOC, and the resting time is not less than the shortest time required for the OCV to reach stability when the battery pack is charged and discharged to the first SOC, the OCV corresponding to the longer resting time can be obtained by standing for a shorter time, thereby improving the calibration efficiency of the SOC-OCV curve.

[0076] In some embodiments, the first cycle number may be greater than a preset cycle number. To improve the fitting speed and accuracy of the first mapping relationship, determining the first mapping relationship corresponding to the first SOC based on the multiple different time lengths and their corresponding second OCVs may include:

[0077] Obtaining a second mapping relationship of the battery pack corresponding to the first SOC when the number of battery cycles is not greater than a preset number of cycles;

[0078] The first fitting coefficient corresponding to the second mapping relationship is used as the initial value of the fitting coefficient, and a plurality of different time lengths and their corresponding second OCVs are fitted to obtain the first mapping relationship.

[0079] Here, the second mapping relationship may represent a correspondence between the rest time of the battery pack after it is charged or discharged to the first SOC and the OCV.

[0080] Exemplarily, the preset cycle number may be 1, the first cycle number may be greater than 1, and the battery cycle number not being greater than the preset cycle number may mean that the battery cycle number is 1.

[0081] Exemplarily, the second mapping relationship can be calibrated when the number of battery cycles is 1. For example, the battery pack can be controlled to discharge at a rate C1 (0.2C < C1 < 0.5C) until the SOC is equal to 100%, and then left to stand for a duration t2 (t2 > 120 min). During the process of leaving it to stand for the duration t2, the second OCVs at multiple different standing durations (t2 - n, t2 - n + 1, …, t2 - 1, t2) are respectively obtained, and based on the multiple different durations and their corresponding second OCVs, the second mapping relationship corresponding to when the SOC is equal to 100% is determined; then, the battery pack is continuously controlled to discharge until the SOC is equal to 95%, and then left to stand for a duration t2 (t2 > 120 min), and during the process of leaving it to stand for the duration t2, the second OCVs at multiple different standing durations (t2 - n, t2 - n + 1, …, t2 - 1, t2) are respectively obtained, and based on the multiple different durations and their corresponding second OCVs, the second mapping relationship corresponding to when the SOC is equal to 95% is determined; the above process is repeated to respectively determine the second mapping relationships corresponding to other values of the SOC until the SOC is equal to 0%.

[0082] In addition, the charging device can also be used to charge the battery pack at a rate C1 (0.2C < C1 < 0.5C) until the SOC is equal to 0%, and then left to stand for a duration t2 (t2 > 120 min). During the process of leaving it to stand for the duration t2, the second OCVs at multiple different standing durations (t2 - n, t2 - n + 1, …, t2 - 1, t2) are respectively obtained, and based on the multiple different durations and their corresponding second OCVs, the second mapping relationship corresponding to when the SOC is equal to 0% is determined; then, the battery pack is continuously charged until the SOC is equal to 5%, and then left to stand for a duration t2 (t2 > 120 min), and during the process of leaving it to stand for the duration t2, the second OCVs at multiple different standing durations (t2 - n, t2 - n + 1, …, t2 - 1, t2) are respectively obtained, and based on the multiple different durations and their corresponding second OCVs, the second mapping relationship corresponding to when the SOC is equal to 5% is determined; the above process is repeated to respectively determine the second mapping relationships corresponding to other values of the SOC until constant voltage charging to 0.05C, that is, the SOC is equal to 100%.

[0083] Exemplarily, the relationship curve between the standing duration and the OCV during each process of leaving it to stand for the duration t2 can be as shown in Figure 5.

[0084] Specifically, the relationship curve between the standing duration and the OCV can be fitted by the least squares method using the following formula to obtain the fitting formula, that is, the second mapping relationship. After obtaining the fitting formula, the OCV at different standing durations can be calculated.

[0085] The fitting formula can be:

[0086] Wherein, V(t) is OCV, and t is the static time. The fitting formula may be based on the second-order equivalent circuit model shown in FIG4 .

[0087] The static expression formula after discharge can be:

[0088] Among them, V ocv (SOC, T) is the OCV that changes with temperature and SOC, V p1 (0) is the first-order polarization voltage at t = 0, V p2 (0) is the second-order polarization voltage at time t = 0, τ1 is the first-order time constant, and τ is the second-order time constant.

[0089] Then, after obtaining the second mapping relationship corresponding to the first SOC of the battery pack when the cycle number is 1, the first fitting coefficient in the second mapping relationship can be used as the initial value of the fitting coefficient to fit multiple different time lengths and their corresponding second OCVs to obtain the first mapping relationship.

[0090] In this way, the first fitting coefficient of the second mapping relationship corresponding to the smaller number of cycles is used as the initial value of the fitting coefficient to fit the first mapping relationship corresponding to the larger number of cycles, which can improve the fitting speed and accuracy.

[0091] In some embodiments, to improve the fitting accuracy of the first mapping relationship, the fitting of multiple different time lengths and their corresponding second OCVs to obtain the first mapping relationship may include:

[0092] Obtaining a preset coefficient range corresponding to the fitting coefficient in the first mapping relationship;

[0093] Based on a preset coefficient range, fitting multiple different time lengths and their corresponding second OCVs is performed to obtain a second fitting coefficient;

[0094] A first mapping relationship is determined according to the second fitting coefficient.

[0095] Here, the first mapping relationship may include multiple fitting coefficients, and a corresponding preset coefficient range may be set for each fitting coefficient. Based on the preset coefficient range, multiple different time lengths and their corresponding second OCVs are fitted.

[0096] For example, after the battery pack ages, the first coefficient (a1 or V ocv (SOC, T)) will generally become larger, and the second coefficient (a2 or V p1 (0)) will become larger, and the coefficient of the third term (a3 or ) will become smaller, and the coefficient of the fourth term (a4 or V p2 (0)) will become larger, and the coefficient of the fifth term (a5 or Based on this rule, the value range of each coefficient after aging can be limited, as shown in Table 1.

[0097] Table 1- Coefficient value range

[0098] For example, when the number of cycles is 1, the corresponding fitting result can be:

[0099] f(x)=a+b*exp(-c*x)+d*exp(-e*x)

[0100] Coefficients(with 95%confidence bounds):

[0101] a=3.33(3.33,3.33)

[0102] b=0.02713(0.02687,0.02738)

[0103] c=0.001196(0.00118,0.001211)

[0104] d=0.1149(0.1142,0.1156)

[0105] e=0.02249(0.02224,0.02274)

[0106] Goodness of fit:

[0107] SSE:0.01055

[0108] R-square: 0.9861

[0109] Adjusted R-square:0.9861

[0110] RMSE: 0.001213;

[0111] When the number of cycles is greater than 1, the corresponding fitting result can be:

[0112] f(x)=a+b*exp(-c*x)+d*exp(-e*x)

[0113] Coefficients(with 95%confidence bounds):

[0114] a=3.33(2.951,3.709)

[0115] b=0.02712(-0.4207,0.475)

[0116] c=0.0011(fixed at bound)

[0117] d=0.115(0.04914,0.1809)

[0118] e=0.02248(0.009771,0.03519)

[0119] Goodness of fit:

[0120] SSE:0.003975

[0121] R-square: 0.9632

[0122] Adjusted R-square:0.9622

[0123] RMSE:0.005854.

[0124] In this way, by setting a preset coefficient range corresponding to the fitting coefficient in the first mapping relationship and performing fitting based on the preset coefficient range, the fitting accuracy of the first mapping relationship can be improved.

[0125] In S120, the first mapping relationship may represent a correspondence between the rest time of the battery pack after being charged or discharged to a first SOC and the OCV. Based on the first mapping relationship, the OCV of the battery pack when it is rested for the first rest time after being charged or discharged to the first SOC may be determined. This OCV may be the first OCV corresponding to the first SOC. The first rest time may be no less than the minimum time required for the OCV of the battery pack to reach stability when being charged or discharged to the first SOC.

[0126] That is, according to the first mapping relationship, it can be determined that the battery pack is charged or discharged to a first SOC and then left to stand until the OCV of the battery pack reaches a stable second OCV.

[0127] In S130 , based on the first mapping relationships corresponding to the multiple first SOCs, multiple first SOCs and their corresponding first OCVs can be determined. Then, the multiple first SOCs and their corresponding first OCVs can be fitted to obtain a first SOC-OCV curve. Since the first mapping relationship corresponds to the battery pack at the first cycle number, the first SOC-OCV curve obtained based on the first mapping relationship also corresponds to the first cycle number.

[0128] In some embodiments, since the first preset time period during which the battery pack remains stationary is short during the process of calibrating the first mapping relationship, the battery pack temperature may be high. To improve the accuracy of the SOC-OCV curve calibration, before S130, the method may further include:

[0129] For each of the plurality of first OCVs, the following steps are performed:

[0130] Obtaining a first temperature of the battery pack when it is continuously at rest for a first preset time after being charged or discharged to a first SOC, a temperature conversion coefficient corresponding to the first temperature, and a third OCV of the battery pack at a preset standard temperature;

[0131] Correcting the first OCV according to the first temperature, the temperature conversion coefficient, and the third OCV to obtain a corrected first OCV;

[0132] S130 may include:

[0133] Based on the plurality of first SOCs and their respectively corresponding corrected first OCVs, a first SOC-OCV curve corresponding to the battery pack at a first cycle number is determined.

[0134] Here, the first OCV corresponding to each first SOC may be corrected.

[0135] For example, the preset standard temperature may be 25° C. The formula for correcting the first OCV according to the first temperature, the temperature conversion coefficient and the third OCV may be as follows: V T0 =a T0 ×V T ×(T-T0)

[0136] Among them, V T is the first OCV, T is the first temperature, T0 is the preset standard temperature (25°C), V T0 is the third OCV at the preset standard temperature, a T0 is the temperature conversion coefficient corresponding to the first temperature.

[0137] In this way, the first OCV can be corrected by the first temperature of the battery pack when it is continuously stationary for a first preset time after being charged and discharged to the first SOC, the temperature conversion coefficient corresponding to the first temperature, and the third OCV of the battery pack at the preset standard temperature. The first OCV can be temperature compensated, thereby improving the accuracy of the calibrated SOC-OCV curve.

[0138] In some embodiments, to obtain a more accurate temperature conversion coefficient, obtaining the temperature conversion coefficient may include:

[0139] Obtain the corresponding relationship between the temperature of the battery pack and the SOC-OCV curve at the second cycle number;

[0140] Determine, based on the correspondence between the temperature and the SOC-OCV curve, a second SOC-OCV curve corresponding to the first temperature and a third SOC-OCV curve corresponding to the preset standard temperature;

[0141] Finding a fourth OCV corresponding to the first SOC from the second SOC-OCV curve, and finding a fifth OCV corresponding to the first SOC from the third SOC-OCV curve;

[0142] A temperature conversion coefficient is determined according to the first temperature, the preset standard temperature, the fourth OCV, and the fifth OCV.

[0143] Here, the SOC-OCV curves corresponding to different temperatures under different cycle numbers can be pre-calibrated, so that the SOC-OCV curves corresponding to the first temperature and the preset standard temperature can be determined respectively, and then the OCV corresponding to the first SOC can be found from the SOC-OCV curves corresponding to the first temperature and the preset standard temperature respectively.

[0144] For example, the temperature conversion coefficient may be calculated as follows:

[0145] Among them, a T0 is the temperature conversion coefficient, V T0 is the fifth OCV, V T is the fourth OCV, T is the first temperature, and T0 is the preset standard temperature.

[0146] For example, if the first SOC=50%, the fifth OCV (35°C)=3.250, and the fourth OCV (25°C)=3.255, then

[0147] For example, V T0 、V T The positions of , T and T0 can be shown in FIG6 .

[0148] In this way, when calculating the temperature conversion coefficient, the influence of the number of battery cycles on the temperature conversion coefficient is taken into account, so it is more accurate.

[0149] In some embodiments, the first cycle number is greater than a preset cycle number, and the second cycle number is not greater than the preset cycle number. To improve the accuracy of the temperature conversion coefficient, the above-mentioned acquisition of the corresponding relationship between the temperature of the battery pack and the SOC-OCV curve at the second cycle number includes:

[0150] At the second cycle number, for each of the multiple temperatures, the following steps are performed to obtain SOC-OCV curves corresponding to the multiple temperatures:

[0151] Under the temperature, obtain the corresponding OCV of the battery pack at multiple SOCs;

[0152] An SOC-OCV curve corresponding to the temperature is determined according to the multiple SOCs and their corresponding OCVs.

[0153] Here, the second cycle number may be a smaller cycle number.

[0154] Exemplarily, the preset number of cycles may be 1, the first number of cycles may be greater than 1, and the second number of cycles may be 1.

[0155] Specifically, the SOC-OCV curves corresponding to the battery pack at multiple temperatures can be calibrated under the second cycle number. For each temperature, the OCVs corresponding to multiple SOCs at that temperature can be obtained. Based on the multiple SOCs and their corresponding OCVs, the SOC-OCV curve corresponding to that temperature can be determined.

[0156] In this way, the second cycle number is not greater than the preset cycle number, and the temperature conversion coefficient is determined based on the corresponding relationship between the temperature and the SOC-OCV curve at a smaller cycle number, which can make the temperature conversion coefficient more accurate.

[0157] In some embodiments, to further improve the accuracy of the temperature conversion coefficient, the above-mentioned steps of respectively obtaining the OCV corresponding to the battery pack at multiple SOCs include:

[0158] Perform the following steps for each of the multiple SOCs to obtain the OCVs corresponding to the multiple SOCs:

[0159] Controlling the battery pack to remain stationary for a first stationary time after being charged or discharged to SOC;

[0160] When the battery pack is kept at rest for a first rest period, the OCV of the battery pack is collected to obtain the OCV corresponding to the SOC.

[0161] Here, in the process of calibrating the correspondence between the temperature and the SOC-OCV curve, the battery pack can be controlled to remain stationary for a first resting time after being charged and discharged to the SOC. When the battery pack remains stationary for the first resting time, the OCV of the battery pack is collected to obtain the OCV corresponding to the SOC.

[0162] In this way, since the OCV corresponding to the SOC is collected when the resting time is the first resting time, and the first resting time is not less than the shortest time required for the OCV to reach stability when the battery pack is charged and discharged to the first SOC, the OCV corresponding to the SOC is more accurate, and the correspondence between the calibrated temperature and the SOC-OCV curve is more accurate, and the temperature conversion coefficient calculated based on the correspondence between the temperature and the SOC-OCV curve is more accurate.

[0163] In some embodiments, to improve the accuracy of DCR, the method may further include:

[0164] For each of the multiple SOCs at the first cycle number, the following steps are performed to obtain the DCR corresponding to the multiple SOCs at the first cycle number:

[0165] When the battery pack is charged to the SOC at the first cycle, charging is stopped and the battery pack is left to stand still;

[0166] While the battery pack is continuously at rest, obtaining a charging current of the battery pack, a sixth OCV of the battery pack when charging stops, and a seventh OCV of the battery pack when the battery pack is continuously at rest for a second preset time period;

[0167] A DCR corresponding to the SOC of the battery pack at a first cycle number is determined according to the sixth OCV, the seventh OCV, and the charging current.

[0168] Battery pack aging also affects DCR accuracy, so the relationship between SOC and DCR can be calibrated for different cycle times. The first cycle time can be any cycle time. For the first cycle time, the DCR corresponding to multiple SOCs can be determined. For example, the DCR corresponding to SOCs of 0%, 5%, 10%, ..., 95%, and 100% can be determined.

[0169] For example, the charging current of the battery pack may be a constant charging current. The second preset time period may be any time period greater than 5 seconds and less than 30 seconds.

[0170] For example, the calculation formula of DCR may be:

[0171] The current may be a charging current, V1 is the sixth OCV, and V0 is the seventh OCV.

[0172] Exemplarily, the positions of V1 and V0 may be as shown in FIG. 7 .

[0173] In this way, the effect of cycle aging on DCR is taken into account when determining the DCR corresponding to the SOC, thereby improving the accuracy of DCR.

[0174] In some implementations, to improve the accuracy of the SOH, the method may further include:

[0175] Obtain a second SOC of the battery pack at the first cycle number;

[0176] When the second SOC falls within the preset SOC range, obtaining an eighth OCV, a charging capacity, a third SOC when fully charged, and a first SOC-OCV curve corresponding to the first cycle number of the battery pack;

[0177] Find the fourth SOC corresponding to the eighth OCV from the first SOC-OCV curve;

[0178] The SOH of the battery pack at the first cycle number is determined according to the charging capacity, the third SOC, and the fourth SOC.

[0179] Here, the eighth OCV may be the OCV after the bottom end of the battery pack has been left to rest, and the fourth SOC may be the calibrated SOC obtained by looking up the SOC_OCV table based on the OCV after the bottom end has been left to rest.

[0180] For example, if the battery pack is a lithium iron battery, the preset SOC range may be less than 30%; if the battery pack is a ternary battery, the preset SOC range may be less than 50%.

[0181] For example, the calculation formula of SOH may be as follows:

[0182] Among them, Chg_Capacity is the charging capacity, SOC(OCV) is the fourth SOC, and SOCfull is the third SOC when fully charged.

[0183] In this way, when determining the SOH of the battery pack, the effect of cycle aging on the SOH is taken into account, thereby improving the accuracy of the SOH.

[0184] In addition, after the first SOC-OCV curve, DCR, and SOH are determined, the first SOC-OCV curve, DCR, and SOH may be updated to a battery management system (BMS) via a host computer.

[0185] Based on the same inventive concept, the present embodiment further provides a SOC-OCV curve calibration device for a battery pack. The SOC-OCV curve calibration device for a battery pack provided in the present embodiment is described in detail below with reference to FIG8 .

[0186] FIG8 shows a schematic structural diagram of an SOC-OCV curve calibration device for a battery pack provided in one embodiment of the present application.

[0187] As shown in FIG8 , the SOC-OCV curve calibration device of the battery pack may include:

[0188] A first acquisition module 801 is configured to acquire first mapping relationships corresponding to a plurality of first SOCs of the battery pack at a first number of cycles, wherein the first mapping relationships represent corresponding relationships between the rest time of the battery pack after it is charged or discharged to the first SOC and the OCV;

[0189] A first determining module 802 is configured to determine, for each first SOC, based on a first mapping relationship corresponding to the first SOC, an OCV corresponding to a first rest period as a first OCV corresponding to the first SOC, wherein the first rest period is not less than a minimum time required for the OCV to reach stability when the battery pack is charged or discharged to the first SOC;

[0190] The second determining module 803 is configured to determine a first SOC-OCV curve corresponding to the battery pack at a first cycle number based on a plurality of first SOCs and their corresponding first OCVs.

[0191] Thus, the first SOC-OCV curve corresponding to the battery pack at the first cycle number can be calibrated, and the first SOC-OCV curve corresponding to the battery pack at the first cycle number can be determined. This takes into account the impact of battery pack cycle aging on the SOC-OCV curve, thereby improving the accuracy of the SOC-OCV curve. In addition, in the process of calibrating the first SOC-OCV curve corresponding to the first cycle number based on multiple first SOCs and their corresponding first OCVs, the first OCV corresponding to each first SOC can be determined by the correspondence between the rest time and OCV after the battery pack is charged and discharged to the first SOC at the first cycle number (that is, the first mapping relationship). The OCV corresponding to the first rest time in the first mapping relationship can be used as the first OCV corresponding to the first SOC. The first rest time is not less than the shortest time required for the OCV to reach stability when the battery pack is charged and discharged to the first SOC. That is, during the calibration process, the battery pack does not need the actual first rest time when charging and discharging to the first SOC, so the calibration speed is faster. In this way, the SOC-OCV curve of the battery pack can be calibrated quickly and accurately.

[0192] In some implementations, to improve calibration efficiency, the first acquisition module 801 may include:

[0193] For each of the multiple first SOCs, the following steps are performed respectively to obtain first mapping relationships corresponding to the multiple first SOCs:

[0194] a control submodule, configured to control the battery pack to remain stationary for a first preset time after being charged or discharged to a first SOC, wherein the first preset time is less than a minimum time required for the OCV of the battery pack to reach stability when being charged or discharged to the first SOC;

[0195] The first acquisition submodule is configured to respectively acquire the second OCV of the battery pack when the battery pack is kept at rest for a plurality of different time periods while the battery pack is kept at rest for a first preset time period;

[0196] The first determining submodule is configured to determine a first mapping relationship corresponding to the first SOC according to a plurality of different time lengths and their respective corresponding second OCVs.

[0197] In some embodiments, the first number of cycles is greater than a preset number of cycles. To improve the fitting speed and accuracy of the first mapping relationship, the determining submodule may include:

[0198] A first acquiring unit is configured to acquire a second mapping relationship corresponding to a first SOC of the battery pack when the number of battery cycles is not greater than a preset number of cycles, the second mapping relationship representing a correspondence between a rest time of the battery pack after being charged or discharged to the first SOC and the OCV;

[0199] The fitting unit is configured to fit a plurality of different time lengths and their corresponding second OCVs using a first fitting coefficient corresponding to the second mapping relationship as an initial value of the fitting coefficient to obtain a first mapping relationship.

[0200] In some implementations, to improve the fitting accuracy of the first mapping relationship, the fitting unit may include:

[0201] An acquiring subunit, configured to acquire a preset coefficient range corresponding to the fitting coefficient in the first mapping relationship;

[0202] A fitting subunit, configured to fit a plurality of different time lengths and their corresponding second OCVs based on a preset coefficient range to obtain a second fitting coefficient;

[0203] The determining subunit is configured to determine the first mapping relationship according to the second fitting coefficient.

[0204] In some embodiments, in order to improve the accuracy of calibrating the SOC-OCV curve, the device may further include:

[0205] Before determining a first SOC-OCV curve corresponding to the battery pack at a first cycle number based on the plurality of first SOCs and their corresponding first OCVs, the following steps are performed for each of the plurality of first OCVs:

[0206] a second acquisition module, configured to acquire a first temperature of the battery pack when it is continuously at rest for a first preset time after being charged or discharged to a first SOC, a temperature conversion coefficient corresponding to the first temperature, and a third OCV of the battery pack at a preset standard temperature;

[0207] a correction module, configured to correct the first OCV according to the first temperature, the temperature conversion coefficient, and the third OCV to obtain a corrected first OCV;

[0208] The second determining module 803 may include:

[0209] The second determining submodule is configured to determine a first SOC-OCV curve corresponding to the battery pack at a first cycle number based on the plurality of first SOCs and their respectively corresponding corrected first OCVs.

[0210] In some embodiments, in order to obtain a more accurate temperature conversion coefficient, the second acquisition module may include:

[0211] A second acquisition submodule is used to obtain the corresponding relationship between the temperature of the battery pack and the SOC-OCV curve at the second cycle number;

[0212] a third determining submodule, configured to determine, based on a correspondence between temperature and SOC-OCV curve, a second SOC-OCV curve corresponding to the first temperature and a third SOC-OCV curve corresponding to a preset standard temperature;

[0213] a search submodule, configured to search the fourth OCV corresponding to the first SOC from the second SOC-OCV curve, and to search the fifth OCV corresponding to the first SOC from the third SOC-OCV curve;

[0214] The fourth determining submodule is configured to determine a temperature conversion coefficient according to the first temperature, the preset standard temperature, the fourth OCV, and the fifth OCV.

[0215] In some embodiments, the first cycle number is greater than a preset cycle number, and the second cycle number is not greater than the preset cycle number. To improve the accuracy of the temperature conversion coefficient, the second acquisition submodule may include:

[0216] At the second cycle number, for each of the multiple temperatures, the following steps are performed to obtain SOC-OCV curves corresponding to the multiple temperatures:

[0217] The second acquisition unit is used to respectively acquire the OCV corresponding to the battery pack at multiple SOCs under the temperature;

[0218] The determining unit is configured to determine an SOC-OCV curve corresponding to the temperature according to a plurality of SOCs and their corresponding OCVs.

[0219] In some embodiments, to further improve the accuracy of the temperature conversion coefficient, the second obtaining unit may include:

[0220] Perform the following steps for each of the multiple SOCs to obtain the OCVs corresponding to the multiple SOCs:

[0221] A control subunit, configured to control the battery pack to remain stationary for a first stationary time after being charged or discharged to the SOC;

[0222] The collecting subunit is used to collect the OCV of the battery pack when the battery pack is kept at rest for a first rest time, so as to obtain the OCV corresponding to the SOC.

[0223] In some embodiments, to improve the accuracy of DCR, the apparatus may further include:

[0224] For each of the multiple SOCs at the first cycle number, the following steps are performed to obtain the DCR corresponding to the multiple SOCs at the first cycle number:

[0225] A control module, configured to control the battery pack to stop charging and keep it at rest when the battery pack is charged to the SOC under the first cycle number;

[0226] a third acquisition module, configured to acquire, while the battery pack is continuously at rest, a charging current of the battery pack, a sixth OCV when the battery pack stops charging, and a seventh OCV when the battery pack is continuously at rest for a second preset time;

[0227] The third determining module is configured to determine a DCR corresponding to the SOC of the battery pack at a first cycle number according to the sixth OCV, the seventh OCV, and the charging current.

[0228] In some embodiments, to improve the accuracy of the SOH, the apparatus may further include:

[0229] A fourth acquisition module, configured to acquire a second SOC of the battery pack at the first cycle number;

[0230] a fifth acquisition module, configured to acquire, when the second SOC falls within a preset SOC range, an eighth OCV, a charging capacity, a third SOC when fully charged, and a first SOC-OCV curve corresponding to the first cycle number of the battery pack;

[0231] a search module, configured to search the fourth SOC corresponding to the eighth OCV from the first SOC-OCV curve;

[0232] The fourth determining module is configured to determine a state of health (SOH) of the battery pack corresponding to the first number of cycles according to the charging capacity, the third SOC, and the fourth SOC.

[0233] FIG9 shows a schematic structural diagram of an electronic device provided by an embodiment of the present application.

[0234] As shown in FIG9 , the electronic device 9 is a block diagram of an exemplary hardware architecture of an electronic device capable of implementing the SOC-OCV curve calibration method and SOC-OCV curve calibration apparatus for a battery pack according to the embodiments of the present application. The electronic device may refer to the electronic device in the embodiments of the present application.

[0235] The electronic device 9 may include a processor 901 and a memory 902 storing computer program instructions.

[0236] Specifically, the processor 901 may include a central processing unit (CPU), or an application-specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present application.

[0237] The memory 902 may include a large-capacity memory for data or instructions. By way of example and not limitation, the memory 902 may include a hard disk drive (HDD), a floppy disk drive, flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a universal serial bus (USB) drive, or a combination of two or more of these. Where appropriate, the memory 902 may include removable or non-removable (or fixed) media. Where appropriate, the memory 902 may be internal or external to the integrated gateway disaster recovery device. In certain embodiments, the memory 902 is a non-volatile solid-state memory. In certain embodiments, the memory 902 may include a read-only memory (ROM), a random access memory (RAM), a magnetic disk storage media device, an optical storage media device, a flash memory device, an electrical, optical, or other physical / tangible memory storage device. Therefore, generally, the memory 902 includes one or more tangible (non-transitory) computer-readable storage media (e.g., a memory device) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors), it is operable to perform the operations described with reference to the method according to one aspect of the present application.

[0238] The processor 901 reads and executes computer program instructions stored in the memory 902 to implement any one of the SOC-OCV curve calibration methods for the battery pack in the above embodiments.

[0239] In one example, the electronic device may further include a communication interface 903 and a bus 904. As shown in FIG9, the processor 901, the memory 902, and the communication interface 903 are connected via the bus 904 and communicate with each other.

[0240] The communication interface 903 is mainly used to implement communication between various modules, devices, units and / or equipment in the embodiments of the present application.

[0241] Bus 904 comprises hardware, software or both, couples the parts of electronic equipment to each other.For example, and not limitation, bus can comprise accelerated graphics port (AGP) or other graphics buses, enhanced industry standard architecture (EISA) bus, front side bus (FSB), hypertransport (HT) interconnection, industry standard architecture (ISA) bus, infinite bandwidth interconnection, low pin count (LPC) bus, memory bus, micro channel architecture (MCA) bus, peripheral component interconnection (PCI) bus, PCI-Express (PCI-X) bus, serial advanced technology attachment (SATA) bus, video electronics standard association local (VLB) bus or other suitable bus or two or more of these combinations.In suitable cases, bus 904 can comprise one or more buses.Although the present application embodiment describes and shows specific bus, the application considers any suitable bus or interconnection.

[0242] The electronic device can execute the SOC-OCV curve calibration method of the battery pack in the embodiment of the present application, thereby realizing the SOC-OCV curve calibration method and device of the battery pack described in combination with Figures 1 to 8.

[0243] In addition, in conjunction with the battery pack SOC-OCV curve calibration method in the above-mentioned embodiments, embodiments of the present application may provide a computer storage medium for implementation. The computer storage medium stores computer program instructions; when executed by a processor, the computer program instructions implement any of the battery pack SOC-OCV curve calibration methods in the above-mentioned embodiments.

[0244] It should be understood that the present application is not limited to the specific configurations and processes described above and illustrated in the figures. For the sake of brevity, a detailed description of known methods is omitted here. In the above embodiments, several specific steps are described and illustrated as examples. However, the method process of the present application is not limited to the specific steps described and illustrated. Those skilled in the art can make various changes, modifications, and additions, or change the order of the steps after understanding the spirit of the present application.

[0245] The functional blocks shown in the above-described block diagram can be implemented as hardware, software, firmware or a combination thereof. When implemented in hardware, they can be, for example, electronic circuits, application specific integrated circuits (ASICs), appropriate firmware, plug-ins, function cards, etc. When implemented in software, the elements of the present application are programs or code segments that are used to perform the required tasks. The program or code segment can be stored in a machine-readable medium, or transmitted on a transmission medium or a communication link by a data signal carried in a carrier wave. "Machine-readable medium" can include any medium that can store or transmit information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROMs, flash memories, erasable ROMs (EROMs), floppy disks, CD-ROMs, optical disks, hard disks, optical fiber media, radio frequency (RF) links, etc. The code segment can be downloaded via a computer network such as the Internet, an intranet, etc.

[0246] It should also be noted that the exemplary embodiments mentioned in this application describe some methods or systems based on a series of steps or devices. However, this application is not limited to the order of the above steps. In other words, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0247] Aspects of the present application have been described above with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to the embodiments of the present application. It should be understood that each box in the flowchart and / or block diagram and the combination of each box in the flowchart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer or other programmable data processing device to produce a machine so that these instructions executed via the processor of the computer or other programmable data processing device enable the implementation of the function / action specified in one or more boxes of the flowchart and / or block diagram. This processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor or a field programmable logic circuit. It is also understood that each box in the block diagram and / or the flowchart and the combination of the boxes in the block diagram and / or the flowchart can also be implemented by the dedicated hardware that performs the specified function or action, or can be implemented by the combination of dedicated hardware and computer instructions.

[0248] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and components may be replaced with equivalents without departing from the scope of the present application. In particular, the various technical features described in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions within the scope of the claims.

Claims

1. A method for calibrating a state of charge (SOC)-open circuit voltage (OCV) curve of a battery pack, comprising: Acquire first mapping relationships respectively corresponding to a plurality of first SOCs of the battery pack at a first cycle number, wherein the first mapping relationship represents a correspondence between a rest time of the battery pack after it is charged and discharged to the first SOC and the OCV; For each of the first SOCs, according to the first mapping relationship corresponding to the first SOC, determining that the OCV corresponding to the first rest time is the first OCV corresponding to the first SOC, and the first rest time is not less than the shortest time required for the OCV to reach stability when the battery pack is charged and discharged to the first SOC; Based on the plurality of first SOCs and their respective corresponding first OCVs, a first SOC-OCV curve corresponding to the battery pack at the first cycle number is determined.

2. The method according to claim 1, wherein: The obtaining of first mapping relationships respectively corresponding to a plurality of first SOCs of the battery pack at a first cycle number includes: For each of the first SOCs, the following steps are performed to obtain first mapping relationships corresponding to the first SOCs: Controlling the battery pack to remain stationary for a first preset time after being charged and discharged to the first SOC, wherein the first preset time is shorter than the shortest time required for the OCV of the battery pack to reach stability when being charged and discharged to the first SOC; When the battery pack is kept at rest for the first preset time, obtaining the second OCV of the battery pack when the battery pack is kept at rest for a plurality of different time periods respectively; A first mapping relationship corresponding to the first SOC is determined according to the multiple different time lengths and their respective corresponding second OCVs.

3. The method according to claim 2, wherein: The first cycle number is greater than a preset cycle number, and determining a first mapping relationship corresponding to the first SOC according to the multiple different time lengths and their respective corresponding second OCVs includes: When the number of battery cycles is not greater than the preset number of cycles, a second mapping relationship corresponding to the first SOC of the battery pack is obtained, wherein the second mapping relationship represents a corresponding relationship between the static time of the battery pack after being charged and discharged to the first SOC and the OCV; The first fitting coefficient corresponding to the second mapping relationship is used as an initial value of the fitting coefficient, and a plurality of different time lengths and their corresponding second OCVs are fitted to obtain the first mapping relationship.

4. The method according to claim 3, wherein: The fitting of a plurality of different time lengths and their corresponding second OCVs to obtain the first mapping relationship includes: Obtaining a preset coefficient range corresponding to the fitting coefficient in the first mapping relationship; Based on the preset coefficient range, fitting the plurality of different time lengths and their corresponding second OCVs respectively to obtain a second fitting coefficient; The first mapping relationship is determined according to the second fitting coefficient.

5. The method according to claim 2, before determining the first SOC-OCV curve corresponding to the battery pack at the first cycle number based on the plurality of first SOCs and their respective corresponding first OCVs, the method further comprises: For each of the first OCVs in the plurality of first OCVs, the following steps are performed respectively: Acquire a first temperature of the battery pack when it is continuously at rest for a first preset time after being charged and discharged to the first SOC, a temperature conversion coefficient corresponding to the first temperature, and a third OCV of the battery pack at a preset standard temperature; Correcting the first OCV according to the first temperature, the temperature conversion coefficient and the third OCV to obtain a corrected first OCV; The determining, based on the plurality of first SOCs and their respective corresponding first OCVs, a first SOC-OCV curve corresponding to the battery pack at the first number of cycles includes: Based on the plurality of first SOCs and the respectively corresponding corrected first OCVs, a first SOC-OCV curve corresponding to the battery pack at the first cycle number is determined.

6. The method according to claim 5, wherein: Obtaining the temperature conversion coefficient includes: Obtaining a corresponding relationship between the temperature of the battery pack and the SOC-OCV curve at the second cycle number; Determine, according to the correspondence between the temperature and the SOC-OCV curve, a second SOC-OCV curve corresponding to the first temperature and a third SOC-OCV curve corresponding to the preset standard temperature; Finding a fourth OCV corresponding to the first SOC from the second SOC-OCV curve, and finding a fifth OCV corresponding to the first SOC from the third SOC-OCV curve; The temperature conversion coefficient is determined according to the first temperature, the preset standard temperature, the fourth OCV, and the fifth OCV.

7. The method according to claim 6, wherein: The first cycle number is greater than a preset cycle number, the second cycle number is not greater than the preset cycle number, and the acquiring the corresponding relationship between the temperature of the battery pack and the SOC-OCV curve at the second cycle number includes: At the second cycle number, for each temperature of the multiple temperatures, the following steps are performed respectively to obtain SOC-OCV curves corresponding to the multiple temperatures respectively: Under the temperature, respectively obtaining the OCV corresponding to the battery pack at multiple SOCs; According to the plurality of SOCs and their corresponding OCVs, a SOC-OCV curve corresponding to the temperature is determined.

8. The method according to claim 7, wherein: The respectively obtaining the OCV corresponding to the battery pack at multiple SOCs includes: The following steps are performed for each of the multiple SOCs to obtain the OCVs corresponding to the multiple SOCs: Controlling the battery pack to remain stationary for the first stationary time after being charged and discharged to the SOC; When the battery pack is kept at rest for the first rest time, the OCV of the battery pack is collected to obtain the OCV corresponding to the SOC.

9. The method according to claim 1, further comprising: For each SOC in the plurality of SOCs at the first number of cycles, the following steps are performed respectively to obtain a DC internal resistance DCR corresponding to each of the plurality of SOCs at the first number of cycles: Controlling the battery pack to stop charging and keep it at rest when the battery pack is charged to the SOC at the first number of cycles; During the process of the battery pack being continuously at rest, obtaining a charging current of the battery pack, a sixth OCV when the battery pack stops charging, and a seventh OCV when the battery pack is continuously at rest for a second preset time period; A DCR of the battery pack corresponding to the SOC at the first number of cycles is determined according to the sixth OCV, the seventh OCV, and the charging current.

10. The method according to claim 1, further comprising: Obtaining a second SOC of the battery pack at the first cycle number; When the second SOC belongs to a preset SOC range, obtaining an eighth OCV, a charging capacity, a third SOC when fully charged, and the first SOC-OCV curve corresponding to the first cycle number of the battery pack; Finding a fourth SOC corresponding to the eighth OCV from the first SOC-OCV curve; A health state SOH corresponding to the battery pack at the first cycle number is determined according to the charging capacity, the third SOC and the fourth SOC.

11. A SOC-OCV curve calibration device for a battery pack, the device comprising: A first acquisition module, used to acquire first mapping relationships respectively corresponding to a plurality of first SOCs of the battery pack at a first number of cycles, wherein the first mapping relationship represents a correspondence between a rest time of the battery pack after it is charged and discharged to the first SOC and the OCV; a first determining module, configured to determine, for each of the first SOCs, according to the first mapping relationship corresponding to the first SOC, that the OCV corresponding to the first rest time is the first OCV corresponding to the first SOC, wherein the first rest time is not less than the shortest time required for the OCV to reach stability when the battery pack is charged or discharged to the first SOC; The second determination module is configured to determine a first SOC-OCV curve corresponding to the battery pack at the first cycle number based on the plurality of first SOCs and their respectively corresponding first OCVs.

12. An electronic device, comprising: a processor and a memory storing computer program instructions; When the processor executes the computer program instructions, the SOC-OCV curve calibration method of the battery pack according to any one of claims 1 to 10 is implemented.

13. A computer storage medium having computer program instructions stored thereon, wherein the computer program instructions, when executed by a processor, implement the SOC-OCV curve calibration method for a battery pack according to any one of claims 1 to 10.

14. A computer program product, wherein when instructions in the computer program product are executed by a processor of an electronic device, the electronic device executes the SOC-OCV curve calibration method for a battery pack according to any one of claims 1 to 10.

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