Method and device for determining soc of battery cell, battery management system and electronic equipment

Abstract

The application provides a kind of determination method, device, battery management system, electronic equipment and computer readable storage medium of electric core SOC, the method comprises: according to the current temperature of the electric core to be measured from the target relationship curve in the pre-set multiple relationship curves;Wherein, relationship curve is characterized in that at each state of charge SOC, the change of open-circuit voltage OCV of the electric core to be measured changes with temperature, each relationship curve corresponds to a temperature;According to target OCV-SOC curve of relationship curve and standard OCV-SOC curve;According to the current OCV of the electric core to be measured and target OCV-SOC curve, the SOC of the electric core to be measured is determined. Through the method, the accuracy when estimating the SOC of the electric core is improved, and the error is reduced.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more specifically, to a method, apparatus, battery management system, electronic device, and computer-readable storage medium for determining the state of charge (SOC) of a battery cell. Background Technology

[0002] With the widespread application and rapid development of various portable electronic devices and electric vehicles, the performance requirements for chemical power sources are becoming increasingly stringent. Lithium-ion batteries, due to their numerous advantages such as high energy density, long cycle life, high average output voltage, high output power, excellent cycle performance, long service life, and environmental friendliness, have been widely used in various devices.

[0003] The State of Charge (SOC) of a battery is an internal parameter that cannot be directly obtained through instrument measurement. Furthermore, SOC is easily affected by factors such as temperature, charge / discharge conditions, and battery aging. Therefore, accurate SOC estimation is a major challenge for battery management systems. Currently, most methods use the open-circuit voltage method for SOC estimation, which estimates the SOC by measuring the battery's open-circuit voltage (OCV) and utilizing the principle that OCV is approximately proportional to SOC. However, the battery's open-circuit voltage is also affected by factors such as battery temperature and aging, resulting in low accuracy and large errors in SOC estimation. Summary of the Invention

[0004] The purpose of this application is to provide a method, apparatus, battery management system, electronic device, and computer-readable storage medium for determining the state of charge (SOC) of a battery cell, so as to improve the accuracy of SOC estimation of the battery cell and reduce errors.

[0005] In a first aspect, this application provides a method for determining the State of Charge (SOC) of a battery cell, comprising: determining a target relationship curve from a set of preset relationship curves based on the current temperature of the battery cell under test; wherein the relationship curves characterize the change of the open-circuit voltage (OCV) of the battery cell under test with temperature at each state of charge (SOC), and each relationship curve corresponds to a temperature; determining a target OCV-SOC curve based on the target relationship curve and a standard OCV-SOC curve; wherein the standard OCV-SOC curve characterizes the correspondence between the OCV and SOC of the battery cell under test at a standard temperature; the target OCV-SOC curve characterizes the correspondence between the OCV and SOC of the battery cell under test at the current temperature; and determining the SOC of the battery cell under test based on the current OCV and the target OCV-SOC curve.

[0006] In the above scheme, the OCV-SOC curve at the standard temperature is updated based on the target relationship curve that reflects the change of the open-circuit voltage (OCV) of the cell under test with temperature. The target OCV-SOC curve, which characterizes the correspondence between the OCV and SOC of the cell under test at the current temperature, is determined. Then, the SOC of the cell under test is accurately determined based on the current OCV and the target OCV-SOC curve, thereby improving the accuracy of SOC estimation of the cell and reducing errors.

[0007] In an optional implementation, when the cell under test is in a charging state, the multiple relationship curves are multiple relationship curves of the cell under test in a charging state, and the standard OCV-SOC curve is the standard OCV-SOC curve of the cell under test in a charging state.

[0008] In the above scheme, since the OCV-SOC curve of the battery cell differs between the charging and discharging states, when the battery cell under test is in the charging state, the relationship curve corresponding to the charging state and the standard OCV-SOC curve in the charging state are selected to estimate the SOC of the battery cell under test, thereby improving the accuracy of SOC estimation of the battery cell.

[0009] In an optional implementation, when the cell under test is in a discharging state, the multiple relationship curves are multiple relationship curves of the cell under test in a discharging state, and the standard OCV-SOC curve is the standard OCV-SOC curve of the cell under test in a discharging state.

[0010] In the above scheme, since the OCV-SOC curves of the battery cell differ between the charging and discharging states, when the battery cell under test is in the discharging state, the relationship curve corresponding to the discharging state and the standard OCV-SOC curve in the discharging state are selected to estimate the SOC of the battery cell under test, thereby improving the accuracy of SOC estimation of the battery cell.

[0011] In an optional implementation, before determining the target OCV-SOC curve based on the target relationship curve and the standard OCV-SOC curve, the method further includes: determining the standard OCV-SOC curve from a set of preset OCV-SOC curves based on the cycle period of the cell under test; wherein each OCV-SOC curve corresponds to a cycle period interval, and the cycle period of the cell under test is located in the cycle period interval corresponding to the standard OCV-SOC curve.

[0012] In the above scheme, since the correspondence between the SOC and OCV of the battery cell differs at different cycle periods, when determining the standard OCV-SOC curve, the OCV-SOC curve corresponding to the cycle period of the battery cell under test is selected as the standard OCV-SOC curve to improve the accuracy of SOC estimation of the battery cell.

[0013] In an optional implementation, the first axis of the relationship curve represents SOC, and the second axis represents the ratio of the first difference and the second difference; wherein, the first difference is the difference between the OCV of the cell at the temperature corresponding to the relationship curve and the OCV of the cell at the standard temperature, and the second difference is the difference between the temperature corresponding to the relationship curve and the standard temperature.

[0014] In an optional implementation, determining the target OCV-SOC curve based on the target relationship curve and the standard OCV-SOC curve includes: for each SOC, determining a compensation coefficient based on the target relationship curve; wherein the compensation coefficient is the value on the second coordinate axis of the target relationship curve corresponding to each SOC; based on the formula: Determine the target OCV-SOC curve; wherein, OCV T Let OCV be the OCV of the battery cell under test at the current temperature. t Let T be the OCV of the battery cell under test at the standard temperature, where T is the current temperature of the battery cell under test, and t is the standard temperature. The compensation coefficient is given. The first axis of the target OCV-SOC curve represents SOC, and the second axis represents the OCV of the cell under test at the current temperature.

[0015] Secondly, this application provides a device for determining the State of Charge (SOC) of a battery cell, comprising: a first determining module, configured to determine a target relationship curve from a set of preset relationship curves based on the current temperature of the battery cell under test; wherein the relationship curves characterize the change of the open-circuit voltage (OCV) of the battery cell under test with temperature at each State of Charge (SOC), and each relationship curve corresponds to a temperature; a second determining module, configured to determine a target OCV-SOC curve based on the target relationship curve and a standard OCV-SOC curve; wherein the standard OCV-SOC curve characterizes the correspondence between the OCV and SOC of the battery cell under test at a standard temperature; and the target OCV-SOC curve characterizes the correspondence between the OCV and SOC of the battery cell under test at the current temperature; and a third determining module, configured to determine the SOC of the battery cell under test based on the current OCV of the battery cell under test and the target OCV-SOC curve.

[0016] In an optional implementation, when the cell under test is in a charging state, the multiple relationship curves are multiple relationship curves of the cell under test in a charging state, and the standard OCV-SOC curve is the standard OCV-SOC curve of the cell under test in a charging state.

[0017] In an optional implementation, when the cell under test is in a discharging state, the multiple relationship curves are multiple relationship curves of the cell under test in a discharging state, and the standard OCV-SOC curve is the standard OCV-SOC curve of the cell under test in a discharging state.

[0018] In an optional embodiment, the device further includes a fourth determining module, used to determine the standard OCV-SOC curve from a set of preset OCV-SOC curves based on the cycle period of the cell under test; wherein each OCV-SOC curve corresponds to a cycle period interval, and the cycle period of the cell under test is located in the cycle period interval corresponding to the standard OCV-SOC curve.

[0019] In an optional implementation, the first axis of the relationship curve represents SOC, and the second axis represents the ratio of the first difference and the second difference; wherein, the first difference is the difference between the OCV of the cell at the temperature corresponding to the relationship curve and the OCV of the cell at the standard temperature, and the second difference is the difference between the temperature corresponding to the relationship curve and the standard temperature.

[0020] In an optional implementation, the second determining module is specifically used to determine a compensation coefficient for each SOC based on the target relationship curve; wherein the compensation coefficient is the value on the second coordinate axis of the target relationship curve corresponding to each SOC; based on the formula: (Tt), determine the target OCV-SOC curve; where, OCV T Let OCV be the OCV of the battery cell under test at the current temperature. t Let T be the OCV of the battery cell under test at the standard temperature, where T is the current temperature of the battery cell under test, and t is the standard temperature. The compensation coefficient is given. The first axis of the target OCV-SOC curve represents SOC, and the second axis represents the OCV of the cell under test at the current temperature.

[0021] Thirdly, this application provides a battery management system connected to a battery, the battery including at least one cell, the battery management system being used to perform the cell SOC determination method as described in any of the foregoing embodiments.

[0022] Fourthly, this application provides an electronic device, including: a body, a battery management system, and a battery connected to the battery management system, the battery comprising at least one cell; the battery being used to power the body; and the battery management system being used to perform the cell SOC determination method as described in any of the foregoing embodiments.

[0023] Fifthly, this application provides a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is run by a computer, it performs the cell SOC determination method as described in any of the foregoing embodiments. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope.

[0025] Figure 1 A flowchart illustrating a method for determining the State of Charge (SOC) of a battery cell, as provided in an embodiment of this application;

[0026] Figure 2 A schematic diagram of a relationship curve provided for an embodiment of this application;

[0027] Figure 3 A schematic diagram of the OCV-SOC curves for the charging and discharging states provided in the embodiments of this application;

[0028] Figure 4 This is a structural block diagram of a battery cell SOC determination device provided in an embodiment of this application. Detailed Implementation

[0029] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0030] It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, relational terms such as "first," "second," etc., in the description of this application are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one…" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0031] To improve the accuracy of SOC estimation for battery cells and reduce errors, embodiments of this application provide a method, apparatus, battery management system, electronic device, and computer-readable storage medium for determining the SOC of a battery cell.

[0032] The method for determining the cell SOC provided in this application will be described below.

[0033] Please see Figure 1 , Figure 1 The flowchart illustrates a method for determining the State of Charge (SOC) of a battery cell, as provided in this application embodiment. This method may include:

[0034] Step 101: Determine the target relationship curve from a set of preset relationship curves based on the current temperature of the cell under test.

[0035] In this embodiment of the application, the Battery Management System (BMS) can be pre-configured with multiple relationship curves. These relationship curves characterize the change in the open-circuit voltage (OCV) of the battery cell under test as a function of temperature at various states of charge (SOC), with each relationship curve corresponding to a specific temperature.

[0036] Based on the current temperature of the cell under test, a target relationship curve is determined from a set of pre-configured relationship curves. The temperature corresponding to the target relationship curve is the same as the current temperature of the cell under test.

[0037] For example, the BMS is pre-configured with five relationship curves corresponding to -10℃, 0℃, 10℃, 25℃, and 30℃. If the current temperature of the battery cell under test is 30℃, then the relationship curve corresponding to 30℃ will be used as the target relationship curve.

[0038] Based on the characteristics of battery cells, the relationship between the open-circuit voltage (OCV) and the state of charge (SOC) of a battery cell differs at different temperatures. For example, when the cell temperature is 25℃ and the SOC is 20%, the corresponding OCV is 3.7V; when the cell temperature is 30℃ and the SOC is 20%, the corresponding OCV is 3.5V.

[0039] In order to determine the state of charge (SOC) of a battery cell under test based on its open voltage (OCV) at different temperatures, it is necessary to first determine the target relationship curve corresponding to the current temperature of the battery cell under test.

[0040] As an optional implementation, the first axis of the relationship curve represents the State of Charge (SOC), and the second axis represents the ratio of the first difference to the second difference. The first difference is the difference between the OCV of the cell at the temperature corresponding to the relationship curve and the OCV of the cell at the standard temperature; the second difference is the difference between the temperature corresponding to the relationship curve and the standard temperature.

[0041] The ratio of the first difference to the second difference is defined as the compensation coefficient.

[0042] In some embodiments, such as Figure 2 As shown, the first axis is the horizontal axis, and the second axis is the vertical axis. The horizontal axis represents the state of charge (SOC) of the battery cell, and the vertical axis represents the compensation coefficient.

[0043] In other embodiments, the first coordinate axis is the vertical axis, and the second coordinate axis is the horizontal axis. The vertical axis represents the state of charge (SOC) of the battery cell, and the horizontal axis represents the compensation coefficient.

[0044] The following explains how the relationship curve is determined.

[0045] As an optional implementation, prior to step 101, the cell SOC determination method provided in this application embodiment further includes:

[0046] Under standard temperature, determine the OCV corresponding to each SOC of the battery cell;

[0047] At the first temperature, determine the OCV corresponding to each SOC of the battery cell;

[0048] Based on the OCV corresponding to each SOC of the cell at the standard temperature and the OCV corresponding to each SOC of the cell at the first temperature, the relationship curve corresponding to the first temperature is determined.

[0049] In this embodiment, the battery cell is charged to 100% SOC, left to stand at a standard temperature t, and then the OCV of the battery cell is measured and determined. Then, the SOC of the battery cell is adjusted by discharging at small rates (e.g., 0.04C, 0.05C, 0.06C, etc.). After each SOC adjustment, the battery cell is left to stand at the standard temperature, and the OCV of the battery cell is measured, thereby determining the OCV corresponding to each SOC of the battery cell at the standard temperature.

[0050] Adjust the standard temperature t to the first temperature T, repeat the above steps, and determine the OCV corresponding to each SOC of the cell at the first temperature T.

[0051] After obtaining the OCV corresponding to each SOC of the battery cell at the standard temperature and the OCV corresponding to each SOC of the battery cell at the first temperature, the difference between the OCV corresponding to each SOC of the battery cell at the standard temperature and the OCV corresponding to each SOC of the battery cell at the first temperature can be determined, i.e., the aforementioned first difference. The second difference is the difference between the first temperature and the standard temperature. Through the above process, the compensation coefficient corresponding to each SOC at the first temperature can be determined. Compensation coefficient Represented as:

[0052]

[0053] Among them, OCV T The OCV of the battery cell at the first temperature T, OCV t Let OCV be the cell's value at standard temperature t, where T is the initial temperature and t is the standard temperature.

[0054] Using the cell's State of Charge (SOC) as the horizontal axis, the compensation coefficients for each SOC are... Using the vertical axis as the ordinate, a relationship curve corresponding to the first temperature is generated through fitting.

[0055] It is understandable that by adjusting the first temperature T, the relationship curves corresponding to different temperatures can be determined, thereby determining multiple relationship curves.

[0056] In some embodiments, after determining multiple relationship curves, the multiple relationship curves are stored in the BMS so that when performing step 101, the BMS can directly determine the target relationship curve from the stored multiple relationship curves.

[0057] Step 102: Determine the target OCV-SOC curve based on the target relationship curve and the standard OCV-SOC curve.

[0058] In this embodiment, the standard OCV-SOC curve characterizes the relationship between the OCV and SOC of the cell under test at a standard temperature. The target OCV-SOC curve characterizes the relationship between the OCV and SOC of the cell under test at the current temperature.

[0059] In practical applications, the BMS is configured with a standard OCV-SOC curve. After determining the target relationship curve, the BMS determines the target OCV-SOC curve based on the target relationship curve and the standard OCV-SOC curve.

[0060] Since the standard OCV-SOC curve represents the relationship between the OCV and SOC of the battery cell under test at a standard temperature, and the current temperature of the battery cell differs from the standard temperature, as mentioned earlier, the relationship between the open-circuit voltage (OCV) and the state of charge (SOC) of the battery cell varies at different temperatures. Therefore, determining the SOC of the battery cell under test based solely on its current OCV and the standard OCV-SOC curve will inevitably result in a deviation. Thus, it is necessary to determine the relationship between the OCV and SOC of the battery cell under test at the current temperature based on both the target curve and the standard OCV-SOC curve.

[0061] As an optional implementation, step 102 above may include:

[0062] For each SOC, the compensation coefficient is determined based on the target relationship curve;

[0063] Based on the formula: Determine the target OCV-SOC curve.

[0064] Among them, OCV T Let OCV be the OCV of the battery cell under test at the current temperature. t Let T be the OCV of the battery cell under test at the standard temperature, where T is the current temperature of the battery cell under test, and t is the standard temperature. As a compensation coefficient, the first axis of the target OCV-SOC curve is SOC, and the second axis is the OCV of the cell under test at the current temperature.

[0065] In this embodiment of the application, as described above regarding the target relationship curve, the target relationship curve represents the correspondence between each SOC of the battery cell and the compensation coefficient. After determining the target relationship curve from multiple relationship curves, the standard OCV-SOC curve is updated according to the compensation coefficient corresponding to each SOC in the target relationship curve to obtain the target OCV-SOC curve.

[0066] Specifically, the OCV value of the cell under test can be determined at each SOC (State of Charge) based on the standard relationship curve. t The compensation coefficients under each SOC can be determined based on the target relationship curve, i.e. Under each SOC, OCV t , Substituting T and t into the above formula, we can determine the OCV corresponding to each SOC of the battery cell under test at the current temperature T. T Using the state of charge (SOC) of the battery cell as the first coordinate axis, the corresponding OCV of each SOC of the battery cell under test is... T Using the second coordinate axis, the target OCV-SOC curve is generated through fitting, thereby determining the corresponding relationship between the OCV and SOC of the cell under test at the current temperature T.

[0067] It is understood that in some implementations, the first coordinate axis of the target OCV-SOC curve is the x-axis, and the second coordinate axis is the y-axis. In other implementations, the first coordinate axis of the target OCV-SOC curve is the y-axis, and the second coordinate axis is the x-axis.

[0068] Furthermore, due to the significant voltage hysteresis effect in silicon / graphite hybrid cells, the OCV-SOC curves of these cells differ during charging and discharging. Specifically, at lower SOCs, for the same SOC, the OCV during charging is higher than the OCV during discharging. For example, ... Figure 3 As shown, Figure 3 This is the OCV-SOC curve of a silicon / graphite hybrid battery cell at 25℃. The solid line curve represents the OCV-SOC curve of the cell in the charging state, and the dashed line curve represents the OCV-SOC curve of the cell in the discharging state. Based on... Figure 3 It can be seen that during the charging process, when the SOC of the battery cell is 10%, the OCV of the battery cell is 3.7V; during the discharging process, when the SOC of the battery cell is 10%, the OCV of the battery cell is 3.6V.

[0069] As an optional implementation, when the cell under test is a silicon / graphite hybrid cell, in order to improve the accuracy of determining the cell's SOC, when the cell under test is in a charging state, multiple relationship curves are used, and the standard OCV-SOC curve is used; when the cell under test is in a discharging state, multiple relationship curves are used, and the standard OCV-SOC curve is used.

[0070] In this embodiment, the BMS is pre-configured with multiple relationship curves for the charging state and the discharging state. For example, the BMS is pre-configured with 5 relationship curves corresponding to -10℃, 0℃, 10℃, 25℃ and 30℃ in the charging state, and 5 relationship curves corresponding to -10℃, 0℃, 10℃, 25℃ and 30℃ in the discharging state, for a total of 10 relationship curves.

[0071] Before performing step 101 above, the operating state of the cell under test is determined. When performing step 101, if the cell under test is in a charging state, a target relationship curve is determined from multiple relationship curves under the charging state based on the current temperature of the cell under test. If the cell under test is in a discharging state, the target relationship curve is determined from multiple relationship curves under the discharging state based on the current temperature of the cell under test.

[0072] It is understandable that the relationship curve includes curves for both the charging and discharging states. Therefore, when generating the relationship curve, it is necessary to generate corresponding relationship curves for each of the charging and discharging states separately.

[0073] Specifically, when generating the relationship curve for the charging state, the cell is discharged to 0% SOC and left to stand at a standard temperature t. The OCV of the cell under charging state is then measured and determined. Then, the SOC of the cell is adjusted by charging at small rates (e.g., 0.04C, 0.05C, 0.06C, etc.). After each SOC adjustment, the cell is left to stand at a standard temperature, and the OCV of the cell under charging state is measured. This determines the OCV of the cell under charging state corresponding to each SOC at the standard temperature.

[0074] Adjust the standard temperature t to the first temperature T, repeat the above steps, and determine the OCV of each SOC of the battery cell under the first temperature T.

[0075] After obtaining the OCV of the charging state corresponding to each SOC of the battery cell at the standard temperature and the OCV of the charging state corresponding to each SOC of the battery cell at the first temperature, the relationship curve of the charging state corresponding to the first temperature can be determined. For the specific method, please refer to the description in the foregoing embodiments. For the sake of brevity, it will not be repeated here.

[0076] When generating the relationship curve under discharge conditions, the cell is charged to 100% SOC, left to stand at a standard temperature t, and the OCV under discharge conditions is measured to determine the cell's value. Then, the cell's SOC is adjusted by discharging at small rates (e.g., 0.04C, 0.05C, 0.06C, etc.). After each SOC adjustment, the cell is left to stand at a standard temperature, and the OCV under discharge conditions is measured to determine the OCV under discharge conditions corresponding to each SOC of the cell at the standard temperature.

[0077] Adjust the standard temperature t to the first temperature T, repeat the above steps, and determine the OCV of each SOC of the cell under the discharge state at the first temperature T.

[0078] Accordingly, after obtaining the OCV of the discharge state corresponding to each SOC of the cell at the standard temperature and the OCV of the discharge state corresponding to each SOC of the cell at the first temperature, the relationship curve of the discharge state corresponding to the first temperature under the charging state can be determined. For details, please refer to the description in the foregoing embodiments. For the sake of brevity, it will not be repeated here.

[0079] Because the OCV-SOC curves of silicon / graphite hybrid cells differ during charging and discharging, the BMS is pre-configured with standard OCV-SOC curves for both charging and discharging states.

[0080] When performing step 102, when the cell under test is in a charging state, the target OCV-SOC curve is determined based on the target relationship curve in the charging state and the standard OCV-SOC curve in the charging state; when the cell under test is in a discharging state, the target OCV-SOC curve is determined based on the target relationship curve in the discharging state and the standard OCV-SOC curve in the discharging state.

[0081] Furthermore, prior to step 102 above, the cell SOC determination method provided in this application embodiment further includes:

[0082] The standard OCV-SOC curve is determined from a set of preset OCV-SOC curves based on the cycle period of the cell under test. Each OCV-SOC curve corresponds to a cycle period interval, and the cycle period of the cell under test is located within the cycle period interval corresponding to the standard OCV-SOC curve.

[0083] In this embodiment, considering that the relationship between the SOC and OCV of the battery cell differs at different cycle periods, the BMS is pre-configured with multiple OCV-SOC curves, which are OCV-SOC curves measured at different cycle periods under standard temperature.

[0084] For example, when the cell's cycle life is 100, OCV-SOC curve A is measured and determined, and this OCV-SOC curve A is taken as the cell's OCV-SOC curve within the 0-200 cycle life range. When the cell's cycle life is 300, OCV-SOC curve B is measured and determined, and this OCV-SOC curve B is taken as the cell's OCV-SOC curve within the 201-400 cycle life range. This process is repeated to determine multiple OCV-SOC curves.

[0085] When the cycle period of the cell under test is 150, the OCV-SOC curve A is used as the standard OCV-SOC curve; when the cycle period of the cell under test is 350, the OCV-SOC curve B is used as the standard OCV-SOC curve.

[0086] Step 103: Determine the SOC of the cell under test based on the current OCV and target OCV-SOC curves of the cell under test.

[0087] In this embodiment of the application, after obtaining the target OCV-SOC curve through steps 101-102, the correspondence between the SOC and OCV of the battery cell under test at the current temperature is determined. The SOC of the battery cell under test can then be determined from the target OCV-SOC curve based on its current OCV.

[0088] Based on the same inventive concept, this application also provides a device for determining the state of charge (SOC) of a battery cell. Please refer to... Figure 4 , Figure 4 This application provides a structural block diagram of a cell SOC determination device 400, which includes:

[0089] The first determining module 401 is used to determine a target relationship curve from a set of preset relationship curves based on the current temperature of the cell under test; wherein the relationship curve represents the change of the open circuit voltage OCV of the cell under test with temperature under various states of charge (SOC), and each relationship curve corresponds to a temperature.

[0090] The second determining module 402 is used to determine the target OCV-SOC curve based on the target relationship curve and the standard OCV-SOC curve; wherein, the standard OCV-SOC curve represents the correspondence between the OCV and SOC of the cell under test at a standard temperature; and the target OCV-SOC curve represents the correspondence between the OCV and SOC of the cell under test at the current temperature.

[0091] The third determining module 403 is used to determine the SOC of the battery cell under test based on the current OCV and the target OCV-SOC curve of the battery cell under test.

[0092] In an optional implementation, when the cell under test is in a charging state, the multiple relationship curves are multiple relationship curves of the cell under test in a charging state, and the standard OCV-SOC curve is the standard OCV-SOC curve of the cell under test in a charging state.

[0093] In an optional implementation, when the cell under test is in a discharging state, the multiple relationship curves are multiple relationship curves of the cell under test in a discharging state, and the standard OCV-SOC curve is the standard OCV-SOC curve of the cell under test in a discharging state.

[0094] In an optional embodiment, the device further includes a fourth determining module, used to determine the standard OCV-SOC curve from a set of preset OCV-SOC curves based on the cycle period of the cell under test; wherein each OCV-SOC curve corresponds to a cycle period interval, and the cycle period of the cell under test is located in the cycle period interval corresponding to the standard OCV-SOC curve.

[0095] In an optional implementation, the first axis of the relationship curve represents SOC, and the second axis represents the ratio of the first difference and the second difference; wherein, the first difference is the difference between the OCV of the cell at the temperature corresponding to the relationship curve and the OCV of the cell at the standard temperature, and the second difference is the difference between the temperature corresponding to the relationship curve and the standard temperature.

[0096] In an optional implementation, the second determining module 402 is specifically used to determine a compensation coefficient for each SOC based on the target relationship curve; wherein the compensation coefficient is the value on the second coordinate axis of the target relationship curve corresponding to each SOC; based on the formula: Determine the target OCV-SOC curve; wherein, OCV T Let OCV be the OCV of the battery cell under test at the current temperature. t Let T be the OCV of the battery cell under test at the standard temperature, where T is the current temperature of the battery cell under test, and t is the standard temperature. The compensation coefficient is given. The first axis of the target OCV-SOC curve represents SOC, and the second axis represents the OCV of the cell under test at the current temperature.

[0097] Based on the same inventive concept, embodiments of this application also provide a battery management system (BMS), which is connected to a battery and used to manage the battery and determine the state of charge (SOC) of the cells within the battery. For example, the BMS can determine a target relationship curve from a set of preset relationship curves based on the current temperature of the cell under test, determine a target OCV-SOC curve based on the target relationship curve and a standard OCV-SOC curve, and determine the SOC of the cell under test based on the current OCV and the target OCV-SOC curve.

[0098] This can be achieved using an existing battery management system. For example, for laptops, the battery management system can be the one currently used in laptops, the structure of which is well known in the art and will not be described here.

[0099] The method for determining the cell SOC provided in the battery management system embodiment and the resulting technical effects are the same as those in the aforementioned method embodiment. For the sake of brevity, any parts not mentioned in the battery management system embodiment can be referred to the corresponding content in the aforementioned method embodiment.

[0100] Based on the same inventive concept, this application also provides an electronic device, which includes a body, a battery management system, and a battery connected to the battery management system. The battery includes at least one battery cell. The battery is used to power the body; the battery management system is used to execute the above-described method for determining the state of charge (SOC) of the battery cell, thereby improving the accuracy of SOC estimation and reducing errors.

[0101] Furthermore, embodiments of this application also provide a computer-readable storage medium storing a computer program, which, when executed by a computer, performs the cell SOC determination method as described in the above embodiments.

[0102] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0103] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the displayed or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0104] Furthermore, the units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0105] Furthermore, the functional modules in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0106] It should be noted that if the function is implemented as a software module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0107] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method of determining SOC of a battery cell, the method comprising: The method comprises: determining a target relationship curve from preset relationship curves according to a current temperature of the to-be-tested battery cell; wherein the relationship curves represent changes in open circuit voltage (OCV) of the to-be-tested battery cell with temperature at various states of charge (SOC), and each relationship curve corresponds to a temperature; determining a target OCV-SOC curve according to the target relationship curve and a standard OCV-SOC curve; wherein the standard OCV-SOC curve represents a corresponding relationship between OCV and SOC of the to-be-tested battery cell at a standard temperature; and the target OCV-SOC curve represents a corresponding relationship between OCV and SOC of the to-be-tested battery cell at the current temperature; determining SOC of the to-be-tested battery cell according to a current OCV of the to-be-tested battery cell and the target OCV-SOC curve; wherein the determining of the target OCV-SOC curve according to the target relationship curve and the standard OCV-SOC curve comprises: determining a compensation coefficient for each SOC according to the target relationship curve; wherein the compensation coefficient is a value on a second coordinate axis of the target relationship curve corresponding to each SOC; Based on the formula: Determine the target OCV-SOC curve; wherein, OCV of the battery cell under the current temperature, OCV of the battery cell under the standard temperature, the current temperature of the battery cell, the standard temperature, the compensation coefficient, the first coordinate axis of the target OCV-SOC curve is SOC, and the second coordinate axis is OCV of the battery cell under the current temperature.

2. The method of claim 1, wherein, when the to-be-tested battery cell is in a charging state, the relationship curves are relationship curves of the to-be-tested battery cell in the charging state, and the standard OCV-SOC curve is a standard OCV-SOC curve of the to-be-tested battery cell in the charging state.

3. The method of claim 1, wherein, when the to-be-tested battery cell is in a discharging state, the relationship curves are relationship curves of the to-be-tested battery cell in the discharging state, and the standard OCV-SOC curve is a standard OCV-SOC curve of the to-be-tested battery cell in the discharging state.

4. The method of claim 1-3, wherein, Before the determining of the target OCV-SOC curve according to the target relationship curve and the standard OCV-SOC curve, the method further comprises: determining the standard OCV-SOC curve from preset OCV-SOC curves according to a cycle period of the to-be-tested battery cell; wherein each OCV-SOC curve corresponds to a cycle period interval, and the cycle period of the to-be-tested battery cell is in the cycle period interval corresponding to the standard OCV-SOC curve.

5. The method of claim 1, wherein, The first coordinate axis of the relationship curve represents SOC, and the second coordinate axis represents a ratio of a first difference value and a second difference value; wherein the first difference value is a difference between OCV of the battery cell at the temperature corresponding to the relationship curve and OCV of the battery cell at the standard temperature, and the second difference value is a difference between the temperature corresponding to the relationship curve and the standard temperature.

6. An apparatus for determining SOC of a battery cell, the apparatus comprising: The method comprises: a first determining module configured to determine a target relationship curve from preset relationship curves according to a current temperature of the to-be-tested battery cell; wherein the relationship curves represent changes in open circuit voltage (OCV) of the to-be-tested battery cell with temperature at various states of charge (SOC), and each relationship curve corresponds to a temperature; a second determining module, configured to determine a target OCV-SOC curve according to the target relationship curve and a standard OCV-SOC curve; wherein the standard OCV-SOC curve represents a correspondence between OCV and SOC of the battery cell to be tested at a standard temperature; and the target OCV-SOC curve represents a correspondence between OCV and SOC of the battery cell to be tested at the current temperature; a third determining module, configured to determine the SOC of the battery cell to be tested according to the current OCV of the battery cell to be tested and the target OCV-SOC curve; wherein the determining of the target OCV-SOC curve according to the target relationship curve and the standard OCV-SOC curve comprises: for each SOC, determining a compensation coefficient according to the target relationship curve; wherein the compensation coefficient is a value of the second coordinate axis corresponding to each SOC on the target relationship curve; Based on the formula: Determine the target OCV-SOC curve; wherein, OCV of the battery cell under the current temperature, OCV of the battery cell under the standard temperature, the current temperature of the battery cell, the standard temperature, the compensation coefficient, the first coordinate axis of the target OCV-SOC curve is SOC, and the second coordinate axis is OCV of the battery cell under the current temperature.

7. A battery management system, characterized by, a battery management system connected with the battery, wherein the battery comprises at least one battery cell, and the battery management system is configured to execute the battery cell SOC determination method according to any one of claims 1-5.

8. An electronic device, comprising: comprise: a body, a battery management system, and a battery connected with the battery management system, wherein the battery comprises at least one battery cell; the battery is configured to supply power to the body, and the battery management system is configured to execute the battery cell SOC determination method according to any one of claims 1-5.

9. A computer-readable storage medium, characterized in that, a computer program stored thereon, wherein the computer program is run by a computer to execute the battery cell SOC determination method according to any one of claims 1-5.

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