Charge state determination method and device, vehicle and storage medium

Abstract

The invention provides a state of charge determination method and device, a vehicle and a storage medium, and the method is applied to the technical field of batteries, and comprises the steps: obtaining an open-circuit voltage difference value of a power battery when the vehicle is in a static state, the open-circuit voltage difference value is determined based on a first corresponding relation between the charge state and the open-circuit voltage in the discharge state and a second corresponding relation between the charge state and the open-circuit voltage in the charge state; when the vehicle is in the driving state, a target correction coefficient and a target voltage difference value of the current state are determined, and the target correction coefficient is used for indicating the proportion of the open-circuit voltage difference value of the vehicle in the driving state to the open-circuit voltage difference value of the vehicle in the static state; correcting the target voltage difference value based on the target correction coefficient to obtain a target open-circuit voltage of the power battery; and determining the target charge state based on the target open-circuit voltage and the first corresponding relation. The method can improve the accuracy of the state of charge of the power battery.

Description

Technical Field

[0001] The present application relates to the technical field of batteries, and more particularly, to a method, device, vehicle, and storage medium for determining the state of charge. Background Art

[0002] In the battery management system of a vehicle, there is a mapping relationship between the open circuit voltage (OCV) of the power battery and the state of charge (SOC). The acquisition of OCV is related to the charge and discharge process.

[0003] In related technologies, the OCV during driving is determined by estimating based on the charging SOC-OCV and the discharging SOC-OCV. However, the OCV is affected by the dynamic characteristics of the power battery, resulting in low accuracy of the OCV, and further causing deviations in the correction of the SOC. Therefore, how to improve the accuracy of the state of charge of the power battery has become an urgent problem to be solved. Summary of the Invention

[0004] The present application provides a method, device, vehicle, and storage medium for determining the state of charge, and this method can improve the accuracy of the state of charge of the power battery.

[0005] In a first aspect, a method for determining the state of charge is provided. The method includes:

[0006] Obtain the open circuit voltage difference of the power battery when the vehicle is in a stationary state. The open circuit voltage difference is determined based on a first correspondence between the state of charge and the open circuit voltage in a discharging state and a second correspondence between the state of charge and the open circuit voltage in a charging state;

[0007] If the vehicle is in a driving state, determine a target correction coefficient in the current state and a target voltage difference in the open circuit voltage difference. The target correction coefficient is used to indicate the proportion of the open circuit voltage difference when the vehicle is in a driving state to the open circuit voltage difference when the vehicle is in a stationary state;

[0008] Correct the target voltage difference based on the target correction coefficient to obtain the target open circuit voltage of the power battery;

[0009] Determine the target state of charge based on the target open circuit voltage and the first correspondence.

[0010] In the above technical solution, when the vehicle is in a driving state, the target correction coefficient and the target voltage difference in the current state are determined. The target voltage difference is corrected based on the target correction coefficient to obtain the target open-circuit voltage of the power battery, and the target state of charge is determined based on the target open-circuit voltage and the first corresponding relationship. Compared with the prior art in which the open-circuit voltage is estimated during vehicle driving, in this application, the ratio (target correction coefficient) of the open-circuit voltage difference when the vehicle is in a driving state to the open-circuit voltage difference when the vehicle is in a stationary state is determined, and the target voltage difference is corrected based on the target correction coefficient to accurately determine the open-circuit voltage difference during vehicle driving. The target open-circuit voltage of the power battery can be dynamically determined according to the open-circuit voltage difference, so that the target open-circuit voltage is closer to the true open-circuit voltage during vehicle driving, thereby ensuring the accuracy of the target open-circuit voltage. On this basis, the target state of charge of the power battery is determined through the corresponding relationship between the target open-circuit voltage and the calibrated state of charge and open-circuit voltage, which can improve the accuracy of the target state of charge.

[0011] In addition, by correcting the state of charge displayed on the vehicle's display screen through the target state of charge, the accuracy of the state of charge displayed on the display screen can be ensured, thereby improving the user experience.

[0012] Combined with the first aspect, in some possible implementation manners, the method further includes:

[0013] Obtain the difference between the current current of the power battery and the battery capacity of the power battery when the vehicle is in a stationary state. The battery capacity difference is determined based on the corresponding relationship between the state of charge and the battery capacity in the discharge state and the corresponding relationship between the state of charge and the battery capacity in the charge state.

[0014] The determination of the target voltage difference in the target correction coefficient and the open-circuit voltage difference in the current state includes:

[0015] Based on the current state of charge, the target voltage difference is matched from the open-circuit voltage difference, and the target capacity difference is matched from the battery capacity difference.

[0016] Based on the current current and the target capacity difference, the target correction coefficient is determined.

[0017] In the above technical solution, by obtaining the difference between the current current of the power battery and the battery capacity of the power battery when the vehicle is in a stationary state, and determining the target correction coefficient according to the target capacity difference matched by the current state of charge and the current current of the power battery; since the ratio of the capacity change of the power battery is the same as the ratio of the voltage change, the ratio of the voltage change is determined by the capacity change of the power battery, and then the target correction coefficient in the driving state of the vehicle is determined, ensuring the accuracy of the target correction coefficient (the ratio of the open-circuit voltage difference in the driving state of the vehicle to the open-circuit voltage difference in the stationary state of the vehicle) in the driving state of the vehicle, and further ensuring the accuracy of the target open-circuit voltage in the driving state of the vehicle.

[0018] Combined with the first aspect and the above implementation manners, in some possible implementation manners, determining the target correction coefficient based on the current current and the target capacity difference includes:

[0019] Determining the capacity change amount of the power battery based on a preset acquisition period and the current current;

[0020] Determining the ratio of the capacity change amount to the target capacity difference as the target correction coefficient.

[0021] In the above technical solution, the capacity change amount of the power battery is determined through a preset acquisition period and the current current of the power battery, and the ratio of the capacity change amount to the target capacity difference is determined as the target correction coefficient; since the ratio of the capacity change of the power battery is the same as the ratio of the voltage change, the ratio of the open-circuit voltage change is determined through the capacity change of the power battery, and the target correction coefficient can be accurately determined during the driving process of the vehicle, thereby ensuring the accuracy of the target open-circuit voltage during the driving process of the vehicle.

[0022] Combined with the first aspect and the above implementation manners, in some possible implementation manners, correcting the target voltage difference based on the target correction coefficient to obtain the target open-circuit voltage of the power battery includes:

[0023] Determining the product of the target correction coefficient and the target voltage difference as the hysteresis voltage;

[0024] Determining the target open-circuit voltage of the power battery based on the hysteresis voltage.

[0025] In the above technical solution, the product of the target correction coefficient and the target voltage difference is determined as the hysteresis voltage, and based on the hysteresis voltage, the target open-circuit voltage of the power battery is determined; when the vehicle is in a driving state, the hysteresis voltage changes dynamically according to the battery performance of the power battery, and the hysteresis voltage cannot be directly measured and determined. Moreover, the ratio of the change in the battery capacity of the power battery in the vehicle is the same as the ratio of the voltage change. By weighting the target voltage difference with the target correction parameter, the accuracy of the hysteresis voltage can be ensured. On this basis, determining the target open-circuit voltage of the power battery based on the hysteresis voltage can ensure the accuracy of the target open-circuit voltage when the vehicle is in a driving state.

[0026] Combined with the first aspect and the above implementation manners, in some possible implementation manners, obtaining the open-circuit voltage difference of the power battery when the vehicle is in a stationary state includes:

[0027] Determining the difference between the open-circuit voltages of charge and discharge in the same state of charge in the first correspondence relationship and the second correspondence relationship as the open-circuit voltage difference; or,

[0028] Determining the average value of the differences between the open-circuit voltages of charge and discharge in the same state of charge in the first correspondence relationship and the second correspondence relationship as the open-circuit voltage difference.

[0029] In the above technical solution, the difference between the open-circuit voltages of charge and discharge in the same state of charge in the first correspondence relationship and the second correspondence relationship is determined as the open-circuit voltage difference; or, the average value of the differences between the open-circuit voltages of charge and discharge in the same state of charge in the first correspondence relationship and the second correspondence relationship is determined as the open-circuit voltage difference; through the discharge SOC-OCV and the charge SOC-OCV, the open-circuit voltage difference under the same SOC can be determined, and thus, based on the open-circuit voltage difference and the target correction coefficient, the accurate target open-circuit voltage during driving can be obtained, ensuring the accuracy of the target open-circuit voltage.

[0030] Combined with the first aspect and the above implementation manners, in some possible implementation manners, determining the target state of charge based on the target open-circuit voltage and the first correspondence relationship includes:

[0031] If the open-circuit voltage difference is the difference between the open-circuit voltages of charge and discharge in the same state of charge, determining the target state of charge based on the target open-circuit voltage and the first correspondence relationship;

[0032] If the open-circuit voltage difference is the average value of the differences between the open-circuit voltages of charge and discharge in the same state of charge, determining the target state of charge based on the target open-circuit voltage and the third correspondence relationship, where the third correspondence relationship is determined based on the average value of the differences between the open-circuit voltages of charge and discharge in the same state of charge in the first correspondence relationship and the second correspondence relationship.

[0033] In the above technical solution, when the open-circuit voltage difference is the difference between the open-circuit voltages during charge and discharge at the same state of charge, based on the target open-circuit voltage and the first correspondence, the target state of charge is determined. When the open-circuit voltage difference is the average value of the differences between the open-circuit voltages during charge and discharge at the same state of charge, based on the target open-circuit voltage and the third correspondence, the target state of charge is determined; when the determination method of the open-circuit voltage difference is different, the reference curve (reference correspondence) of SOC-OCV is different. By aligning the determination method of the open-circuit voltage difference with the reference curve, the accuracy of the target state of charge obtained according to the target open-circuit voltage is ensured, thereby improving the user experience.

[0034] Combined with the first aspect and the above implementation, in some possible implementations, the method further includes: determining whether there is a need to update the target open-circuit voltage;

[0035] If there is a need to update the target open-circuit voltage, update the target open-circuit voltage;

[0036] The determining the target state of charge based on the target open-circuit voltage and the first correspondence includes:

[0037] If there is no need to update the target open-circuit voltage, determine the target state of charge based on the target open-circuit voltage and the first correspondence.

[0038] In the above technical solution, when there is a need to update the target open-circuit voltage, the target open-circuit voltage is updated. When there is no need to update the target open-circuit voltage, the target state of charge is determined based on the target open-circuit voltage and the first correspondence; by determining whether there is a need to update the target open-circuit voltage, it is thus determined whether the updated target open-circuit voltage is accurate. When the target open-circuit voltage is accurate (there is no need to update the target open-circuit voltage), the target state of charge is determined based on the target open-circuit voltage and the first correspondence, which can ensure the accuracy of the target state of charge.

[0039] In a second aspect, a device for determining the state of charge is provided. The device includes:

[0040] An acquisition module, configured to acquire the open-circuit voltage difference of the power battery when the vehicle is in a stationary state, where the open-circuit voltage difference is determined based on the first correspondence between the state of charge and the open-circuit voltage in the discharge state and the second correspondence between the state of charge and the open-circuit voltage in the charge state;

[0041] A determination module, configured to, if the vehicle is in a driving state, determine the target voltage difference between the target correction coefficient in the current state and the open-circuit voltage difference, where the target correction coefficient is used to indicate the proportion of the open-circuit voltage difference when the vehicle is in a driving state to the open-circuit voltage difference when the vehicle is in a stationary state;

[0042] A correction module, configured to correct the target voltage difference based on the target correction coefficient to obtain the target open-circuit voltage of the power battery;

[0043] A calculation module, configured to determine the target state of charge based on the target open-circuit voltage and the first corresponding relationship.

[0044] Combined with the second aspect, in some possible implementation manners, the acquisition module is further configured to:

[0045] Obtain a difference between the current current of the power battery and the battery capacity of the power battery when the vehicle is in a stationary state, where the battery capacity difference is determined based on the corresponding relationship between the state of charge and the battery capacity in the discharge state and the corresponding relationship between the state of charge and the battery capacity in the charge state;

[0046] The determination module is specifically configured to:

[0047] Based on the current state of charge, determine the target voltage difference and the target capacity difference;

[0048] Based on the current current and the target capacity difference, determine the target correction coefficient.

[0049] Combined with the second aspect and the above implementation manners, in some possible implementation manners, the determination module is specifically configured to:

[0050] Based on a preset acquisition period and the current current, determine a capacity change amount of the power battery;

[0051] Determine a ratio of the capacity change amount to the target capacity difference as the target correction coefficient.

[0052] Combined with the second aspect and the above implementation manners, in some possible implementation manners, the correction module is specifically configured to:

[0053] Determine a product of the target correction coefficient and the target voltage difference as a hysteresis voltage;

[0054] Based on the hysteresis voltage, determine the target open-circuit voltage of the power battery.

[0055] Combined with the second aspect and the above implementation manners, in some possible implementation manners, the acquisition module is specifically configured to:

[0056] Determine a difference between open-circuit voltages of charge and discharge at the same state of charge in the first corresponding relationship and the second corresponding relationship as the open-circuit voltage difference; or,

[0057] Determine the average value of the differences in the open-circuit voltages during charge and discharge at the same state of charge between the first corresponding relationship and the second corresponding relationship as the open-circuit voltage difference.

[0058] Combined with the second aspect and the above implementation manners, in some possible implementation manners, the calculation module is specifically configured to:

[0059] If the open-circuit voltage difference is the difference in the open-circuit voltages during charge and discharge at the same state of charge, determine the target state of charge based on the target open-circuit voltage and the first corresponding relationship;

[0060] If the open-circuit voltage difference is the average value of the differences in the open-circuit voltages during charge and discharge at the same state of charge, determine the target state of charge based on the target open-circuit voltage and the third corresponding relationship, where the third corresponding relationship is determined based on the average value of the open-circuit voltages during charge and discharge at the same state of charge between the first corresponding relationship and the second corresponding relationship.

[0061] Combined with the second aspect and the above implementation manners, in some possible implementation manners, the determination module is further configured to: determine whether there is a need to update the target open-circuit voltage;

[0062] If there is a need to update the target open-circuit voltage, update the target open-circuit voltage;

[0063] The calculation module is specifically configured to:

[0064] If there is no need to update the target open-circuit voltage, determine the target state of charge based on the target open-circuit voltage and the first corresponding relationship.

[0065] In a third aspect, a vehicle is provided, including a memory and a processor, where the memory is used to store executable program code; the processor is used to call and run the executable program code from the memory, so that the vehicle executes the method for determining the state of charge in the first aspect or any one of the possible implementation manners of the first aspect.

[0066] In a fourth aspect, a computer-readable storage medium is provided, where the computer-readable storage medium stores computer program code, and when the computer program code runs on a computer, the computer is caused to execute the method for determining the state of charge in the first aspect or any one of the possible implementation manners of the first aspect.

[0067] In a fifth aspect, a computer program product is provided, where the computer program product includes: computer program code, and when the computer program code runs on a computer, the computer is caused to execute the method for determining the state of charge in the first aspect or any one of the possible implementation manners of the first aspect. Description of the Drawings

[0068] Figure 1 It is a schematic diagram of the scenario of a method for determining the state of charge provided by an embodiment of the present application;

[0069] Figure 2 It is a schematic flowchart of a method for determining the state of charge provided by an embodiment of the present application;

[0070] Figure 3 It is a schematic diagram of a charge-discharge SOC-OCV curve provided by an embodiment of the present application;

[0071] Figure 4 It is a schematic diagram of a charge-discharge SOC-ΔV1 curve provided by an embodiment of the present application;

[0072] Figure 5 It is a schematic diagram of another charge-discharge SOC-OCV curve provided by an embodiment of the present application;

[0073] Figure 6 It is a schematic structural diagram of a device for determining the state of charge provided by an embodiment of the present application;

[0074] Figure 7 It is a schematic structural diagram of a vehicle provided by an embodiment of the present application. Detailed implementation manners

[0075] Next, the technical solutions in the present application will be clearly and elaborately described in conjunction with the accompanying drawings. Among them, in the description of the embodiments of the present application, unless otherwise specified, " / " means "or". For example, A / B may represent A or B: "and / or" in the text is merely a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of the present application, "a plurality of" means two or more than two.

[0076] Hereinafter, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as implying or suggesting relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0077] Figure 1 It is a schematic diagram of the scenario of a method for determining the state of charge provided by an embodiment of the present application.

[0078] Exemplarily, Figure 1 In (a) of [reference], it shows a side view of the vehicle 100, Figure 1 In (b) of [reference], it shows a schematic diagram of the interface of the instrument panel in the vehicle 100.

[0079] Exemplarily, such asFigure 1 As shown in (a) in [reference], the vehicle 100 includes a power battery 110, and the state of charge (or remaining battery power, SOC) of the power battery 110 is displayed on the display screen so that the driver can view the remaining battery power through the display screen.

[0080] Optionally, the power battery 110 can be installed at the bottom of the vehicle body (as shown in [reference]), or can be installed under the trunk of the vehicle; of course, it can also be installed under the rear seat. The installation position of the power battery 110 can be determined according to the actual situation and is not specifically limited here. Figure 1 As shown in [reference],

[0081] In the related art, the open circuit voltage (OCV) of the vehicle is estimated through various estimation methods, and the SOC is corrected through the OCV. During the driving process of the vehicle, due to the influence of the dynamic characteristics of the power battery on the OCV, the accuracy of the OCV is low, resulting in a deviation in the SOC correction. The driver cannot perceive the error in the SOC, which affects the driving experience.

[0082] Exemplarily, as shown in (b) in [reference], the SOC of the vehicle is displayed in the interface schematic diagram 120 of the instrument panel in the vehicle. The driver can view the remaining power and remaining available mileage of the vehicle by checking the instrument panel of the vehicle. However, due to the deviation in the SOC correction, although the SOC displayed on the instrument panel is 60%, the actual SOC may be only 57% or even lower; at this time, the cruising range of the vehicle may not reach 500 km, thus affecting the driving experience of the driver. Figure 1

[0083] In view of this, the present application proposes a method, device, vehicle and storage medium for determining the state of charge. Through the embodiments of the present application, the hysteresis voltage and open circuit voltage of the power battery are calculated in real time, and the state of charge of the power battery is corrected through the open circuit voltage to ensure the accuracy of the state of charge of the power battery, thereby improving the driving experience of users.

[0084] Figure 2 It is a schematic flow chart of a method for determining the state of charge provided by an embodiment of the present application.

[0085] Exemplarily, Figure 2 The method shown in [reference] can be executed by the vehicle's vehicle control unit or chip.

[0086] Exemplarily, as shown in [reference], the method 200 for determining the state of charge includes steps S210 - S240. Figure 2

[0087] S210, obtain the open circuit voltage difference of the power battery when the vehicle is in a stationary state.

[0088] ​​Exemplarily, the open-circuit voltage difference of the power battery when the vehicle is in a stationary state is determined based on the first correspondence between the state of charge and the open-circuit voltage in the discharge state (discharge SOC-OCV) and the second correspondence between the state of charge and the open-circuit voltage in the charge state (charge SOC-OCV). Here, the open-circuit voltage difference includes the open-circuit voltage differences corresponding to different states of charge. According to the charge SOC-OCV and the discharge SOC-OCV, the correspondence between the open-circuit voltage difference ΔV and the state of charge (SOC) can be determined. For example, when the state of charge is 30%, the open-circuit voltage difference is ΔV1, and when the state of charge is 40%, the open-circuit voltage difference is ΔV2.

[0089] It should be noted that both the discharge SOC-OCV and the charge SOC-OCV are correspondences when the vehicle is in a stationary state. When the vehicle is in a driving state, the correspondence between the SOC and the OCV in the vehicle changes dynamically.

[0090] In one example, the difference between the open-circuit voltages of charge and discharge at the same state of charge in the first correspondence (discharge SOC-OCV) and the second correspondence (charge SOC-OCV) is determined as the open-circuit voltage difference. Specifically, the OCVs corresponding to the same SOC in the discharge SOC-OCV and the charge SOC-OCV are determined, and the difference between the OCVs corresponding to the same SOC is determined as the open-circuit voltage difference for this SOC. Therefore, the open-circuit voltage differences ΔV corresponding to different SOCs are obtained, and all the ΔVs (ΔVs corresponding to different SOCs) are determined as the open-circuit voltage difference.

[0091] In another example, the average value of the differences between the open-circuit voltages of charge and discharge at the same state of charge in the first correspondence and the second correspondence is determined as the open-circuit voltage difference. Specifically, the OCVs corresponding to the same SOC in the discharge SOC-OCV and the charge SOC-OCV are determined, and the average value of the differences between the OCVs corresponding to the same SOC is determined as the open-circuit voltage difference for this SOC. Therefore, the open-circuit voltage differences ΔV corresponding to different SOCs are obtained, and all the ΔVs (ΔVs corresponding to different SOCs) are determined as the open-circuit voltage difference.

[0092] It can be understood that the open-circuit voltage difference ΔV refers to the change amount of the OCV in the discharge SOC-OCV and the charge SOC-OCV. Therefore, ΔV is a positive value.

[0093] For the above technical solution, the difference in the open-circuit voltage during charge and discharge at the same state of charge in the first corresponding relationship and the second corresponding relationship is determined as the open-circuit voltage difference; alternatively, the average value of the differences in the open-circuit voltage during charge and discharge at the same state of charge in the first corresponding relationship and the second corresponding relationship is determined as the open-circuit voltage difference; through the discharge SOC-OCV and the charge SOC-OCV, the open-circuit voltage difference at the same SOC can be determined, so that according to the open-circuit voltage difference and the target correction coefficient, the accurate target open-circuit voltage during driving can be obtained, ensuring the accuracy of the target open-circuit voltage.

[0094] S220. If the vehicle is in a driving state, determine the target voltage difference in the target correction coefficient and the open-circuit voltage difference in the current state.

[0095] It can be understood that when the vehicle speed is not 0, the vehicle is in a driving state. The current state of the vehicle indicates the current state of charge of the vehicle, that is, the current SOC.

[0096] Exemplarily, when the vehicle is in a driving state, determine the current state of charge of the vehicle, and match the target voltage difference from the open-circuit voltage difference according to the current state of charge. Through the current SOC and the open-circuit voltage difference, the target open-circuit voltage difference of the power battery can be directly determined, ensuring the accuracy of the target open-circuit voltage difference of the power battery, and further ensuring the accuracy of the target open-circuit voltage of the power battery.

[0097] For example, in the open-circuit voltage difference, when the SOC is 90%, the reference open-circuit voltage difference is 0.008V; when the SOC is 80%, the reference open-circuit voltage difference is 0.01V; when the SOC is 60%, the reference open-circuit voltage difference is 0.017V; when the SOC is 30%, the reference open-circuit voltage difference is 0.02V. When the current SOC is 90%, determine that the target open-circuit voltage difference of the power battery is 0.008V, and when the current SOC is 30%, determine that the target open-circuit voltage difference of the power battery is 0.02V.

[0098] Optionally, the current state of charge can be obtained by ampere-hour calculation, or the current state of charge can be obtained by looking up a table according to the current OCV.

[0099] To ensure the accuracy of the target open-circuit voltage difference of the power battery, it is necessary to first obtain the current SOC. When initially verifying the SOC in the vehicle, the current SOC can be calculated according to the historical SOC, or can be dynamically calculated according to the driving parameters of the vehicle.

[0100] In one example, the historical state of charge (SOC) of the previous acquisition period and the maximum available capacity of the power battery are obtained. Based on the current current of the vehicle and the maximum available capacity, the change value of the power of the power battery is determined. And based on the historical SOC and the battery change value, the current SOC of the power battery in the current acquisition period is determined. The historical SOC is positively correlated with the current SOC, and the change value of the power is negatively correlated with the current SOC.

[0101] Optionally, the acquisition period can be determined according to the vehicle performance, or it can be a preset period. The acquisition period can be determined according to the actual situation and will not be specifically limited here.

[0102] Exemplarily, the expression of the current SOC can be represented as follows:

[0103]

[0104] where i represents the current acquisition period, SOC i represents the current state of charge in the current acquisition period, SOC i-1 represents the historical state of charge of the previous acquisition period, I represents the current current of the vehicle, Δt represents the acquisition period, and C max represents the maximum available capacity of the power battery.

[0105] Specifically, the change amount of the capacity of the power battery is determined according to the product of the current current of the vehicle and the acquisition period. The ratio of the change amount of the capacity of the power battery to the maximum available capacity is determined as the change value of the power of the power battery, and the difference between the historical SOC and the change value of the power is determined as the current SOC in the current acquisition period.

[0106] In the above technical solution, by obtaining the historical SOC of the previous acquisition period and the maximum available capacity of the power battery, based on the current current of the vehicle and the maximum available capacity, the change value of the power of the power battery is determined. Furthermore, according to the historical SOC and the battery change value, the current SOC of the power battery in the current acquisition period is determined, which can dynamically calculate the current SOC and ensure the accuracy of the current SOC.

[0107] In another example, the current SOC can be estimated based on the historical SOC. Specifically, the SOC at the historical moment and the cumulative driving mileage in the target time period (from the historical moment to the current moment) are obtained. The predicted SOC consumed is estimated according to the cumulative driving mileage. And the current SOC is determined according to the SOC at the historical moment and the predicted SOC.

[0108] It should be noted that the target correction coefficient is used to indicate the proportion of the open-circuit voltage difference when the vehicle is in a driving state to the open-circuit voltage difference when the vehicle is in a stationary state. When the vehicle is in a driving state, it is difficult to accurately determine the change amount of the open-circuit voltage. Since the capacity change ratio of the power battery is the same as the voltage change ratio, the voltage change ratio is determined through the capacity change of the power battery, and then the target correction coefficient when the vehicle is in a driving state is determined.

[0109] Exemplarily, when the vehicle is in a driving state, the open-circuit voltage (OCV) of the power battery cannot be directly measured and determined, and it is difficult to ensure the accuracy of the OCV. Therefore, when the vehicle is in a driving state, the target correction coefficient of the power battery is dynamically calculated, and the open-circuit voltage difference is corrected by the target correction coefficient, so as to dynamically calculate the target open-circuit voltage of the power battery, which can ensure the accuracy of the target open-circuit voltage of the power battery.

[0110] Exemplarily, when the vehicle is in a driving state, the current of the power battery and the difference in battery capacity of the power battery when the vehicle is in a stationary state are obtained, and the target capacity difference is matched from the battery capacity difference according to the current state of charge, so as to determine the target correction coefficient according to the current of the power battery and the target capacity difference of the power battery.

[0111] Optionally, the determination method of the current state of charge may refer to the determination method in the foregoing disclosed embodiments, and will not be elaborated herein.

[0112] Optionally, the difference in battery capacity of the power battery when the vehicle is in a stationary state can be obtained when the vehicle is in any state; for example, when it is detected that the vehicle is powered on, the difference in battery capacity of the calibrated power battery is obtained, and during driving, the difference in battery capacity of the power battery corresponding to the current state of the vehicle is determined according to the vehicle state. Or, when it is detected that the SOC of the vehicle needs to be updated, the difference in battery capacity of the power battery corresponding to the current state of the vehicle is obtained according to the vehicle state.

[0113] It should be noted that the battery capacity difference is determined based on the correspondence between the state of charge and the battery capacity in the discharge state and the correspondence between the state of charge and the battery capacity in the charge state. The open-circuit voltage difference of the power battery when the vehicle is in a stationary state refers to the C difference corresponding to the same SOC in the correspondence between SOC and C (charge SOC-C) in the charge state and the correspondence between SOC and C (discharge SOC-C) in the discharge state.

[0114] In the above technical solution, by obtaining the difference between the current current of the power battery and the battery capacity of the power battery when the vehicle is in a stationary state, and determining the target correction coefficient based on the target capacity difference matched according to the current state of charge and the current current of the power battery; since the ratio of the capacity change of the power battery is the same as the ratio of the voltage change, the ratio of the voltage change is determined by the capacity change of the power battery, and then the target correction coefficient when the vehicle is in a driving state is determined, ensuring the accuracy of the target correction coefficient (the ratio of the open-circuit voltage difference when the vehicle is in a driving state to the open-circuit voltage difference when the vehicle is in a stationary state), and further ensuring the accuracy of the target open-circuit voltage when the vehicle is in a driving state.

[0115] Specifically, obtain the difference between the current current of the power battery and the battery capacity of the power battery when the vehicle is in a stationary state, match the target capacity difference from the battery capacity difference based on the current state of charge, determine the capacity change of the power battery based on the preset acquisition period and the current current of the power battery, and determine the ratio of the capacity change to the target capacity difference as the target correction coefficient.

[0116] It should be noted that the preset acquisition period has the same meaning as the acquisition period in the disclosed embodiments of the present application.

[0117] Exemplarily, when the open-circuit voltage difference is the difference between the open-circuit voltages of charge and discharge under the same state of charge, the expression of the capacity change of the power battery can be expressed as follows:

[0118] q = I * Δt

[0119] Where, q represents the capacity change of the power battery, I represents the current current of the vehicle. During the charging process, the current current I is negative, and during the discharging process, the current current I is positive. Δt represents the preset acquisition period (or referred to as the acquisition period). The integral result of the acquisition period for the current current of the vehicle during the vehicle driving process is used as the capacity change of the power battery, that is, the product of the acquisition period and the current current of the vehicle is used as the capacity change of the power battery. During the vehicle driving process, the capacity change of the power battery does not exceed the difference between the charging and discharging battery capacities of the power battery when the vehicle is in a stationary state. Therefore, the value range of q is [-C SOC , 0], C SOC represents the target capacity difference of charge and discharge corresponding to the current state of charge.

[0120] Furthermore, the expression of the target correction coefficient can be expressed as follows:

[0121]

[0122] Where, K represents the target correction coefficient, q represents the capacity change of the power battery within the current acquisition period during the vehicle driving process, CSOC It represents the difference in the target charge and discharge capacity corresponding to the current state of charge. Since the ratio of the capacity change of the power battery is the same as the ratio of the voltage change, by the capacity change of the power battery, the ratio of the open-circuit voltage change is determined. Therefore, the value range of K is [0, 1].

[0123] In the above technical solution, by presetting the acquisition period and the current current of the power battery, the capacity change of the power battery is determined, and the ratio of the capacity change to the target capacity difference is determined as the target correction coefficient; since the ratio of the capacity change of the power battery is the same as the ratio of the voltage change, by the capacity change of the power battery, the ratio of the open-circuit voltage change is determined, which can accurately determine the target correction coefficient during the vehicle driving process, and further ensure the accuracy of the target open-circuit voltage during the vehicle driving process.

[0124] It can be understood that the current SOC of the target voltage difference matched from the open-circuit voltage difference is the same as the target capacity difference matched from the battery capacity difference.

[0125] S230, based on the target correction coefficient, correct the target voltage difference to obtain the target open-circuit voltage of the power battery.

[0126] Exemplarily, when the vehicle is in a driving state, according to the current SOC of the vehicle, determine the target voltage difference and the target capacity difference, and determine the target correction coefficient through the current current and the target capacity difference, so as to correct the target voltage difference through the target correction coefficient to obtain the target open-circuit voltage of the power battery.

[0127] Exemplarily, when determining the target correction coefficient and the target voltage difference, determine the product of the target correction coefficient and the target voltage difference as the hysteresis voltage, and determine the target open-circuit voltage of the power battery based on the hysteresis voltage.

[0128] It can be understood that the hysteresis voltage of the power battery refers to the phenomenon that during the charge and discharge process of the power battery, due to the irreversibility in the electrochemical reaction and mass transfer process, the charge curve and the discharge curve of the battery do not completely coincide, forming a voltage difference. Specifically, when performing charge and discharge tests, if the voltages of the battery are compared at the same power (capacity) points, it will be found that the voltage value when charging reaches a certain state of charge is different from the voltage value at the same state of charge when discharging, and this difference is called "hysteresis".

[0129] Specifically, when the vehicle is in a driving state, dynamically determine the target correction coefficient according to the driving parameters of the vehicle, and correct the open-circuit voltage difference through the target correction coefficient to obtain the hysteresis voltage under the current vehicle state.

[0130] For example, the expression of the hysteresis voltage can be shown as follows:

[0131] ΔU = K * ΔV

[0132] Wherein, ΔU represents the hysteresis voltage of the power battery when the vehicle is in a driving state, K represents the target correction coefficient, and ΔV represents the open-circuit voltage difference of the power battery.

[0133] It can be understood that when the vehicle is in a driving state, the hysteresis voltage changes dynamically according to the battery performance of the power battery. However, the hysteresis voltage cannot be directly determined by measuring the vehicle parameters. Since the change ratio of the capacity difference of the power battery during vehicle driving is the same as the change ratio of the voltage difference, and the change ratio of the capacity difference of the power battery during vehicle driving can be determined, the change ratio of the capacity difference of the battery during vehicle driving is used as the change ratio of the voltage difference, that is, the target correction coefficient. In the case of determining the target correction coefficient, the hysteresis voltage is obtained by multiplying the target correction coefficient by the target voltage difference in the stationary state, which can ensure the accuracy of the hysteresis voltage when the vehicle is in a driving state.

[0134] Furthermore, in the case of determining the hysteresis voltage of the power battery, the terminal voltage of the power battery is collected, and the polarization voltage and the voltage of the ohmic internal resistance are calculated. The sum of the terminal voltage, the polarization voltage, the voltage of the ohmic internal resistance, and the hysteresis voltage is determined as the target open-circuit voltage of the power battery.

[0135] For example, the expression of the target open-circuit voltage can be expressed as follows:

[0136] OCV = U 采 + U 极 + U om + ΔU

[0137] Wherein, U 采 represents the terminal voltage of the power battery collected, U 极 represents the polarization voltage, U om represents the voltage of the ohmic internal resistance, and ΔU represents the hysteresis voltage of the power battery when the vehicle is in a driving state.

[0138] In the above technical solution, the product of the target correction coefficient and the target voltage difference is determined as the hysteresis voltage, and based on the hysteresis voltage, the target open-circuit voltage of the power battery is determined; when the vehicle is in a driving state, the hysteresis voltage changes dynamically according to the battery performance of the power battery, and the hysteresis voltage cannot be directly measured and determined. The change ratio of the battery capacity of the power battery in the vehicle is the same as the change ratio of the voltage. By weighting the target voltage difference with the target correction parameter, the accuracy of the hysteresis voltage can be ensured. On this basis, determining the target open-circuit voltage of the power battery based on the hysteresis voltage can ensure the accuracy of the target open-circuit voltage when the vehicle is in a driving state.

[0139] S240. Determine the target state of charge based on the target open-circuit voltage and the first correspondence.

[0140] Exemplarily, when the target open-circuit voltage is calculated, determine whether there is a need to update the target open-circuit voltage. When there is a need to update the target open-circuit voltage, update the target open-circuit voltage; when there is no need to update the target open-circuit voltage, determine the target state of charge based on the target open-circuit voltage and the first correspondence.

[0141] Exemplarily, when there is a need to update the target open-circuit voltage, update the current state of charge according to the target open-circuit voltage, and re-determine the target open-circuit voltage according to the current state of charge. For example, when the open-circuit voltage difference is the difference between the open-circuit voltages during charge and discharge at the same state of charge, look up the table (charging SOC-OCV) according to the target open-circuit voltage to obtain the corresponding state of charge, and determine the state of charge obtained by looking up the table as the current state of charge. Further, update the target correction factor and the target voltage difference according to the current state of charge, so as to realize the update of the target open-circuit voltage until there is no need to update the target open-circuit voltage.

[0142] To improve the accuracy of the target state of charge, it is necessary to ensure the accuracy of judging whether there is a need to update the target open-circuit voltage.

[0143] In one example, obtain the target driving mileage of the vehicle in the driving state, determine whether the target driving mileage is greater than the preset mileage threshold. When the target driving mileage is greater than the preset mileage threshold, determine that there is a need to update the target open-circuit voltage; when the target driving mileage is less than or equal to the preset mileage threshold, determine that there is no need to update the target open-circuit voltage.

[0144] Optionally, the target driving mileage is used to indicate the driving mileage of the vehicle from the last update of the state of charge to the current time.

[0145] In another example, obtain the historical open-circuit voltage calculated in the previous cycle, calculate the voltage difference between the historical open-circuit voltage and the target open-circuit voltage, and determine whether the voltage difference is greater than the preset difference threshold. When the voltage difference is less than or equal to the preset difference threshold, it indicates that the updated target open-circuit voltage is within the error range, and it is determined that there is no need to update the target open-circuit voltage; when the voltage difference is greater than the preset difference threshold, it is determined that there is a need to update the target open-circuit voltage.

[0146] In another example, based on the predicted terminal voltage of the power battery obtained through calculation and the acquired terminal voltage of the power battery, it is determined whether there is a need to update the target open-circuit voltage. Specifically, when the open-circuit voltage difference is the difference between the open-circuit voltages of charge and discharge at the same state of charge, the corresponding open-circuit voltage is obtained by looking up the table (charging SOC-OCV) according to the current state of charge. The difference between the open-circuit voltage obtained by looking up the table and the target voltage (the target voltage includes the voltage of the ohmic internal resistance, the polarization voltage, and the hysteresis voltage) is determined as the predicted terminal voltage (the open-circuit voltage obtained by looking up the table - the voltage of the ohmic internal resistance - the polarization voltage - the hysteresis voltage).

[0147] Further, the terminal voltage difference between the predicted terminal voltage and the acquired terminal voltage is determined. When the terminal voltage difference is less than or equal to the preset difference threshold, it is determined that there is no need to update the target open-circuit voltage; when the terminal voltage difference is greater than the preset difference threshold, it is determined that there is a need to update the target open-circuit voltage.

[0148] Optionally, the preset difference threshold can be 5mv, 6mv, etc. The preset difference threshold can be determined according to the actual situation and is not specifically limited here.

[0149] In the above technical solution, when there is a need to update the target open-circuit voltage, the target open-circuit voltage is updated. When there is no need to update the target open-circuit voltage, based on the target open-circuit voltage and the first corresponding relationship, the target state of charge is determined; by determining whether there is a need to update the target open-circuit voltage, it is thus determined whether the updated target open circuit is accurate. When the target open-circuit voltage is accurate (there is no need to update the target open-circuit voltage), according to the target open-circuit voltage and the first corresponding relationship, the target state of charge is determined, which can ensure the accuracy of the target state of charge.

[0150] It can be understood that when the target open-circuit voltage is determined, the target state of charge can be determined by looking at the corresponding relationship between the state of charge and the open-circuit voltage.

[0151] In one example, when the open-circuit voltage difference is the difference between the open-circuit voltages of charge and discharge at the same state of charge, based on the target open-circuit voltage and the first corresponding relationship, the target state of charge is determined. For example, the first corresponding relationship is discharge SOC-OCV, and the corresponding target state of charge can be obtained according to the target open-circuit voltage.

[0152] In another example, when the open-circuit voltage difference is the average value of the differences between the open-circuit voltages of charge and discharge at the same state of charge, based on the target open-circuit voltage and the third corresponding relationship, the target state of charge is determined. The third corresponding relationship is determined according to the average value of the differences between the open-circuit voltages of charge and discharge at the same state of charge in the first corresponding relationship and the second corresponding relationship.

[0153] Specifically, the average value of the difference in the open-circuit voltage during charge and discharge at the same state of charge in the discharge SOC-OCV (the first correspondence) and the charge SOC-OCV (the second correspondence) is determined to generate a third correspondence between the average open-circuit voltage and the state of charge. Furthermore, the corresponding target state of charge can be obtained based on the target open-circuit voltage.

[0154] In the above technical solution, when the open-circuit voltage difference is the difference in the open-circuit voltage during charge and discharge at the same state of charge, based on the target open-circuit voltage and the first correspondence, the target state of charge is determined. When the open-circuit voltage difference is the average value of the difference in the open-circuit voltage during charge and discharge at the same state of charge, based on the target open-circuit voltage and the third correspondence, the target state of charge is determined; when the determination method of the open-circuit voltage difference is different, the reference curve (reference correspondence) of the SOC-OCV is different. By aligning the determination method of the open-circuit voltage difference with the reference curve, the accuracy of the target state of charge obtained based on the target open-circuit voltage is ensured, thereby improving the user experience.

[0155] In addition, in the case of determining the target state of charge, it is further confirmed whether the state of charge displayed on the display screen needs to be updated.

[0156] Exemplarily, the state of charge displayed on the display screen in the vehicle is determined, and the difference between the displayed state of charge and the target state of charge is determined. When the difference is less than or equal to the preset threshold, there is no need to update the state of charge displayed on the display screen; when the difference is greater than the preset threshold, the state of charge displayed on the display screen is updated, that is, the displayed state of charge is replaced with the target state of charge.

[0157] Optionally, the preset threshold can be 2%, 3%, etc. The preset threshold can be determined according to the actual situation and is not specifically limited here.

[0158] For example, if the SOC displayed on the current display screen is 50% and the target SOC is 40%, then the target SOC "40%" is displayed on the display screen. Or, if the SOC displayed on the current display screen is 50% and the target SOC is 51%, then the SOC on the display screen remains unchanged.

[0159] In the above technical solution, when the vehicle is in a driving state, the target correction coefficient and the target voltage difference in the current state are determined, the target voltage difference is corrected based on the target correction coefficient to obtain the target open-circuit voltage of the power battery, and the target state of charge is determined based on the target open-circuit voltage and the first corresponding relationship; compared with the prior art where the open-circuit voltage is estimated during vehicle driving, in this application, the ratio (target correction coefficient) of the open-circuit voltage difference when the vehicle is in a driving state to the open-circuit voltage difference when the vehicle is in a stationary state is determined, and the target voltage difference is corrected based on the target correction coefficient to accurately determine the open-circuit voltage difference during vehicle driving, and the target open-circuit voltage of the power battery can be dynamically determined according to the open-circuit voltage difference, so that the target open-circuit voltage is closer to the true open-circuit voltage during vehicle driving, thereby ensuring the accuracy of the target open-circuit voltage. On this basis, the target state of charge of the power battery is determined through the corresponding relationship between the target open-circuit voltage and the calibrated state of charge and open-circuit voltage, which can improve the accuracy of the target state of charge.

[0160] In addition, by correcting the state of charge displayed on the vehicle's display screen through the target state of charge, the accuracy of the state of charge displayed on the display screen can be ensured, thereby improving the user experience.

[0161] The following is a refinement of an embodiment where the difference in the open-circuit voltage of charge and discharge at the same state of charge in the discharge SOC-OCV and the charge SOC-OCV is the open-circuit voltage difference.

[0162] Figure 3 It is a schematic diagram of a charge-discharge SOC-OCV curve provided by an embodiment of the present application.

[0163] Taking the discharge SOC-OCV as the reference line, the difference in the OCV of charge and discharge at the same SOC in the discharge SOC-OCV and the charge SOC-OCV is determined as the open-circuit voltage difference; for example, the change amount from point A in the discharge SOC-OCV corresponding to SOC of 25% to point B in the charge SOC-OCV is determined as the open-circuit voltage difference ΔV1 at SOC of 25%.

[0164] Table 1

[0165]

[0166]

[0167] Table 1 is a schematic table of the charge-discharge SOC-OCV correspondence.

[0168] Exemplarily, as shown in Table 1, at the same state of charge (SOC), the open-circuit voltage (OCV) during charging is different from the OCV during discharging. The difference in open-circuit voltage ΔV1 is determined based on the change in charging OCV and discharging OCV at the same SOC, and the corresponding relationship between SOC and ΔV1 is constructed.

[0169] Figure 4 It is a schematic diagram of a charge-discharge SOC-ΔV1 curve provided by an embodiment of the present application.

[0170] Exemplarily, as Figure 4 shown, based on the data relationship between SOC and ΔV1 in Table 1, the SOC-ΔV1 curve is constructed.

[0171] Please continue to refer to Figure 3 , since the ratio of the change in battery capacity of the power battery is the same as the ratio of the change in voltage, the difference in charge and discharge at the same SOC between the discharge SOC-C (C is the battery capacity) and the charge SOC-C is determined as the battery capacity difference, and then the corresponding relationship between SOC and ΔC1 is constructed.

[0172] When the vehicle is in motion, the current SOC of the vehicle is obtained. Based on the current SOC and SOC-ΔV1, ΔV is obtained (for example, ΔV is obtained by looking up the SOC-ΔV1 curve according to the current SOC), and based on the current SOC and SOC-ΔC1, ΔC is obtained. The product of the current current (the charging state current is negative and the discharging state current is positive) and the acquisition period is determined as the capacity change. Since the open-circuit voltage difference is the difference in SOC between charge and discharge at the same SOC, the limit range of the capacity change is [-ΔC, 0], and the ratio of the capacity change to ΔC is determined as the target correction coefficient (the change ratio of the capacity, that is, the change ratio of the voltage, with the limit range of [0, 1]). The product of the target correction coefficient and ΔV is determined as the hysteresis voltage.

[0173] Furthermore, the terminal voltage of the power battery is collected, and the sum of the terminal voltage, the voltage of the ohmic internal resistance, the polarization voltage, and the hysteresis voltage is determined as the target open-circuit voltage. When the target open-circuit voltage needs to be updated, the target open-circuit voltage is continuously iteratively updated until the target OCV does not need to be updated, and the target SOC is obtained by looking up the discharge SOC-OCV with the target open-circuit voltage, and the SOC on the display screen is corrected according to the target SOC.

[0174] For example, when the vehicle is in the discharging state, the discharging current is positive, and the upper limit value of the capacity change is 0, then the calculated target OCV is the sum of the terminal voltage, the voltage of the ohmic internal resistance, and the polarization voltage, and the target SOC is obtained by looking up the discharge SOC-OCV with the target OCV.

[0175] Alternatively, when the vehicle is in a charging state, the charging current is negative, the capacity change amount determined according to the charging current is negative, and thus the determined hysteresis voltage is negative. The collected terminal voltage can be pulled down by the hysteresis voltage, so that the target open-circuit voltage falls within the discharge SOC-OCV, and the target SOC is obtained.

[0176] The following is a refinement of the solution where the average value of the differences in the open-circuit voltages of charge and discharge at the same state of charge in the discharge SOC-OCV and the charge SOC-OCV is taken as the open-circuit voltage difference.

[0177] Figure 5 It is a schematic diagram of another charge-discharge SOC-OCV curve provided by an embodiment of the present application.

[0178] Taking the mean SOC-OCV as the reference line (constructing the mean SOC-OCV based on the average of the charging OCV and the discharging OCV at the same SOC), the average value of the differences in the OCVs of charge and discharge at the same SOC in the discharge SOC-OCV and the charge SOC-OCV is determined as the open-circuit voltage difference. For example, the change amount from point A in the discharge SOC-OCV corresponding to an SOC of 25% to point C in the mean SOC-OCV is determined as the open-circuit voltage difference ΔV2 (ΔV1 = 2 * ΔV2) for an SOC of 25%.

[0179] Exemplarily, at the same SOC, the charging OCV in the charging state is different from the discharging OCV in the discharging state. The open-circuit voltage difference ΔV2 is determined through the change amounts of the charging OCV and the discharging OCV at the same SOC, and the SOC-ΔV2 correspondence is constructed.

[0180] Please continue to refer to Figure 5 Since the ratio of the change in the battery capacity of the power battery is the same as the ratio of the voltage change, the difference in the charge and discharge at the same SOC in the discharge SOC-C (C is the battery capacity) and the charge SOC-C is determined as the battery capacity difference, and then the SOC-ΔC2 (ΔC1 = 2 * ΔC2) correspondence is constructed.

[0181] When the vehicle is in motion, obtain the current state of charge (SOC) of the vehicle. Based on the current SOC and SOC-ΔV2, obtain ΔV (for example, look up ΔV from the SOC-ΔV2 curve according to the current SOC), and based on the current SOC and SOC-ΔC2, obtain ΔC. Determine the capacity change amount by multiplying the current current (negative for the charging state current and positive for the discharging state current) by the acquisition period. Since the open-circuit voltage difference is the difference in SOC between charging and discharging at the same SOC, the limit range of the capacity change amount is [-ΔC / 2, ΔC / 2], and determine the ratio of the capacity change amount to ΔC as the target correction coefficient (the change ratio of the capacity, that is, the change ratio of the voltage, with the limit range of [0,1]). Determine the hysteresis voltage by multiplying the target correction coefficient by ΔV.

[0182] Further, collect the terminal voltage of the power battery, and determine the target open-circuit voltage as the sum of the terminal voltage, the voltage of the ohmic internal resistance, the polarization voltage, and the hysteresis voltage. When the target open-circuit voltage needs to be updated, continuously iterate and update the target open-circuit voltage until the target OCV no longer needs to be updated, and look up the target SOC from the mean SOC-OCV by the target open-circuit voltage, and correct the SOC on the display screen according to the target SOC.

[0183] For example, when the vehicle is in the discharging state and the discharging current is positive, the capacity change amount determined according to the charging current is positive, and the determined hysteresis voltage is positive. The hysteresis voltage can raise the collected terminal voltage, and then make the target open-circuit voltage (rise) fall on the mean SOC-OCV to obtain the target SOC.

[0184] Or, when the vehicle is in the charging state and the charging current is negative, the capacity change amount determined according to the charging current is negative, and the determined hysteresis voltage is negative. The hysteresis voltage can lower the collected terminal voltage, and then make the target open-circuit voltage fall on the discharging SOC-OCV to obtain the target SOC.

[0185] In the above technical solution, since the capacity change ratio of the power battery is the same as the voltage change ratio, determine the ratio of the voltage change through the capacity change of the power battery, and then determine the target correction coefficient when the vehicle is in the driving state, ensuring the accuracy of the target correction coefficient (the ratio of the open-circuit voltage difference when the vehicle is in the driving state to the open-circuit voltage difference when the vehicle is in the stationary state). On this basis, based on the target correction coefficient, correct the target voltage difference, and the target open-circuit voltage of the power battery can be dynamically determined, thereby ensuring the accuracy of the target open-circuit voltage. On this basis, by looking up the table (discharging SOC-OCV or mean SOC-OCV) with the target open-circuit voltage, determine the target state of charge of the power battery, which can improve the accuracy of the target state of charge.

[0186] In addition, by correcting the state of charge displayed on the vehicle's display screen according to the target state of charge, the accuracy of the state of charge displayed on the display screen can be ensured, thereby improving the user experience.

[0187] It should be understood that the above examples are provided to help those skilled in the art understand the embodiments of the present application, rather than to limit the embodiments of the present application to the specific numerical values or specific scenarios illustrated. Those skilled in the art can obviously make various equivalent modifications or changes according to the above examples, and such modifications or changes also fall within the scope of the embodiments of the present application.

[0188] As described above in conjunction with Figures 1 to 5 the method for determining the state of charge provided by the embodiments of the present application has been described in detail; hereinafter, the device embodiments of the present application will be described in detail in conjunction with Figure 6 and Figure 7 It should be understood that the devices in the embodiments of the present application can execute various methods of the foregoing embodiments of the present application, that is, the specific working processes of the following various products can refer to the corresponding processes in the foregoing method embodiments.

[0189] Figure 6 is a schematic structural diagram of a device for determining the state of charge provided by an embodiment of the present application.

[0190] Exemplarily, as Figure 6 shown, the device 600 for determining the state of charge includes:

[0191] An acquisition module 610: configured to acquire the open-circuit voltage difference of the power battery when the vehicle is in a stationary state, and the open-circuit voltage difference is determined based on a first correspondence between the state of charge and the open-circuit voltage in the discharge state and a second correspondence between the state of charge and the open-circuit voltage in the charge state;

[0192] A determination module 620: configured to determine the target voltage difference between the target correction coefficient and the open-circuit voltage difference in the current state if the vehicle is in a driving state, and the target correction coefficient is used to indicate the proportion of the open-circuit voltage difference when the vehicle is in a driving state to the open-circuit voltage difference when the vehicle is in a stationary state;

[0193] A correction module 630: configured to correct the target voltage difference based on the target correction coefficient to obtain the target open-circuit voltage of the power battery;

[0194] A calculation module 640: configured to determine the target state of charge based on the target open-circuit voltage and the first correspondence.

[0195] Optionally, as an embodiment, the acquisition module 610 is further configured to:

[0196] Obtain the difference between the current current of the power battery and the battery capacity of the power battery when the vehicle is in a stationary state. The battery capacity difference is determined based on the correspondence between the state of charge and the battery capacity in the discharge state and the correspondence between the state of charge and the battery capacity in the charge state;

[0197] The determining module 620 is specifically configured to:

[0198] Based on the current state of charge, match a target voltage difference from the open-circuit voltage difference and match a target capacity difference from the battery capacity difference;

[0199] Based on the current current and the target capacity difference, determine a target correction coefficient.

[0200] Optionally, as an embodiment, the determining module 620 is specifically configured to:

[0201] Based on a preset acquisition period and the current current, determine the capacity change of the power battery;

[0202] Determine the ratio of the capacity change to the target capacity difference as the target correction coefficient.

[0203] Optionally, as an embodiment, the correction module 630 is specifically configured to:

[0204] Determine the hysteresis voltage as the product of the target correction coefficient and the target voltage difference;

[0205] Based on the hysteresis voltage, determine the target open-circuit voltage of the power battery.

[0206] Optionally, as an embodiment, the obtaining module 610 is specifically configured to:

[0207] Determine the difference between the open-circuit voltages of charge and discharge at the same state of charge in the first correspondence and the second correspondence as the open-circuit voltage difference; or,

[0208] Determine the average value of the differences between the open-circuit voltages of charge and discharge at the same state of charge in the first correspondence and the second correspondence as the open-circuit voltage difference.

[0209] Optionally, as an embodiment, the calculating module 640 is specifically configured to:

[0210] If the open-circuit voltage difference is the difference between the open-circuit voltages of charge and discharge at the same state of charge, based on the target open-circuit voltage and the first correspondence, determine the target state of charge;

[0211] If the open-circuit voltage difference is the average value of the differences between the open-circuit voltages during charge and discharge at the same state of charge, based on the target open-circuit voltage and the third correspondence relationship, determine the target state of charge, where the third correspondence relationship is determined based on the average value of the differences between the open-circuit voltages during charge and discharge at the same state of charge in the first correspondence relationship and the second correspondence relationship.

[0212] Optionally, as an embodiment, the determining module 620 is further configured to:

[0213] Determine whether there is a need to update the target open-circuit voltage;

[0214] If there is a need to update the target open-circuit voltage, update the target open-circuit voltage;

[0215] The calculating module 640 is specifically configured to:

[0216] If there is no need to update the target open-circuit voltage, determine the target state of charge based on the target open-circuit voltage and the first correspondence relationship.

[0217] It should be noted that the above state-of-charge determination device 600 is embodied in the form of functional units. The term "module" here can be implemented in software and / or hardware forms, and no specific limitation is made in this regard.

[0218] For example, the "module" can be a software program, a hardware circuit, or a combination of both that implements the above functions. The hardware circuit may include an application specific integrated circuit (ASIC), an electronic circuit, a processor (such as a shared processor, a proprietary processor, or a group of processors, etc.) for executing one or more software or firmware programs, a memory, a merged logic circuit, and / or other suitable components that support the described functions.

[0219] Therefore, in the embodiments of the present application, the units of the various examples described can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. A person skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present application.

[0220] Figure 7 It is a schematic structural diagram of a vehicle provided by an embodiment of the present application.

[0221] Exemplarily, vehicle 700 is Figure 1 the same vehicle as vehicle 100 in

[0222] Exemplarily, such as Figure 7As shown, the vehicle 700 includes: a memory 710 and a processor 720. Among them, an executable program code 730 is stored in the memory 710, and the processor 720 is used to call and execute the executable program code 730 to execute a method for determining the state of charge.

[0223] Exemplarily, the memory 710 can be used to store the relevant programs of the method for determining the state of charge provided in the embodiments of the present application; the processor 720 can call the relevant programs of the method for determining the state of charge stored in the memory 710 to execute the method for determining the state of charge in the embodiments of the present application; for example, obtain the open-circuit voltage difference of the power battery when the vehicle is in a stationary state, and the open-circuit voltage difference is determined based on the first correspondence between the state of charge and the open-circuit voltage in the discharge state and the second correspondence between the state of charge and the open-circuit voltage in the charge state; if the vehicle is in a driving state, determine the target correction coefficient and the target voltage difference of the current state, and the target correction coefficient is used to indicate the proportion of the open-circuit voltage difference when the vehicle is in a driving state to the open-circuit voltage difference when the vehicle is in a stationary state; correct the target voltage difference based on the target correction coefficient to obtain the target open-circuit voltage of the power battery; determine the target state of charge based on the target open-circuit voltage and the first correspondence.

[0224] In this embodiment, the device can be divided into functional modules according to the above method examples. For example, it can correspond to each functional module, or two or more functions can be integrated into one processing module. The above integrated module can be implemented in the form of hardware. It should be noted that the division of modules in this embodiment is illustrative, only a logical function division, and there may be other division methods in actual implementation.

[0225] In the case of dividing each functional module corresponding to each function, the device can also include an acquisition module, a determination module, a correction module, a calculation module, etc. It should be noted that all the relevant contents of each step involved in the above method embodiment can be cited in the function description of the corresponding functional module, and will not be repeated here.

[0226] It should be understood that the device provided in this embodiment is used to execute the above method for determining the state of charge, so the same effect as the above implementation method can be achieved.

[0227] In the case of adopting an integrated unit, the device can include a processing module and a storage module. Among them, when the device is applied to a vehicle, the processing module can be used to control and manage the actions of the vehicle. The storage module can be used to support the vehicle to execute relevant program codes, etc.

[0228] Among them, the processing module can be a processor or a controller, which can implement or execute various exemplary logic blocks, modules, and circuits shown in combination with the disclosure of the present application. The processor can also be a combination that realizes computing functions, such as including a combination of one or more microprocessors, a combination of digital signal processing (DSP) and a microprocessor, etc. The storage module can be a memory.

[0229] In addition, the device provided by the embodiment of the present application can specifically be a chip, a component, or a module. The chip can include a connected processor and a memory; among them, the memory is used to store instructions. When the processor calls and executes the instructions, the chip can execute a method for determining a state of charge provided by the above embodiment.

[0230] The present application also provides a computer-readable storage medium. Computer program code is stored in the computer-readable storage medium. When the computer program code runs on a computer, the computer is caused to execute the above-related method steps to implement a method for determining a state of charge provided by the above embodiment. Among them, the computer-readable storage medium can include, but is not limited to, any type of disk, including floppy disks, optical discs, digital versatile discs (DVDs), compact disc read-only memories (CD-ROMs), microdrives, and magneto-optical discs, read-only memories (ROMs), random access memories (RAMs), erasable programmable read-only memories (EPROMs), electrically erasable programmable read-only memories (EEPROMs), dynamic random access memories (DRAMs), video random access memories (VRAMs), flash memory devices, magnetic cards or optical cards, nano-systems (including molecular memory ICs), or any type of medium or device suitable for storing instructions and / or data.

[0231] The present application also provides a computer program product. When the computer program product runs on a computer, the computer is caused to execute the above-related steps to implement a method for determining a state of charge provided by the above embodiment.

[0232] Among them, the vehicle, computer-readable storage medium, computer program product or chip provided in this application are all used to execute the corresponding methods provided above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding methods provided above, and will not be elaborated here.

[0233] Through the description of the above embodiments, those skilled in the art can understand that for the convenience and brevity of description, only the division of the above functional modules is used as an example. In actual applications, the above functions can be allocated to different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above.

[0234] In the embodiments provided in this application, it should be understood that the disclosed device and method can be implemented in other ways. For example, the device embodiments described above are only illustrative. For example, the division of modules or units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection between each other can be through some interfaces. The indirect coupling or communication connection of the device or unit can be in an electrical, mechanical or other form.

[0235] The above content is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in this application, and all should be covered by the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

1. A method for determining the state of charge, characterized in that, The method includes: Obtaining the open - circuit voltage difference of the power battery when the vehicle is in a stationary state, where the open - circuit voltage difference is determined based on a first correspondence between the state of charge and the open - circuit voltage in a discharge state and a second correspondence between the state of charge and the open - circuit voltage in a charge state; If the vehicle is in a driving state, determining a target correction coefficient for the current state and a target voltage difference in the open - circuit voltage difference, where the target correction coefficient is used to indicate the proportion of the open - circuit voltage difference when the vehicle is in a driving state to the open - circuit voltage difference when the vehicle is in a stationary state; Correcting the target voltage difference based on the target correction coefficient to obtain the target open - circuit voltage of the power battery; Determining a target state of charge based on the target open - circuit voltage and the first correspondence; 2. The method according to claim 1, characterized in that, The method further includes: Obtaining the difference between the current current of the power battery and the battery capacity when the vehicle is in a stationary state, where the battery capacity difference is determined based on a correspondence between the state of charge and the battery capacity in a discharge state and a correspondence between the state of charge and the battery capacity in a charge state; The determining the target correction coefficient for the current state and the target voltage difference in the open - circuit voltage difference includes: Based on the current state of charge, matching the target voltage difference from the open - circuit voltage difference and matching a target capacity difference from the battery capacity difference; Determining the target correction coefficient based on the current current and the target capacity difference; 3. The method according to claim 2, wherein The determining the target correction coefficient based on the current current and the target capacity difference includes: Based on a preset acquisition period and the current current, determining the capacity change amount of the power battery; Determining the ratio of the capacity change amount to the target capacity difference as the target correction coefficient; 4. The method according to claim 1, wherein The correcting the target voltage difference based on the target correction coefficient to obtain the target open - circuit voltage of the power battery includes: Determining the product of the target correction coefficient and the target voltage difference as the hysteresis voltage; Determining the target open - circuit voltage of the power battery based on the hysteresis voltage; 5. The method according to claim 1, characterized in that, The obtaining the open - circuit voltage difference of the power battery when the vehicle is in a stationary state includes: Determining the difference between the open - circuit voltages of charge and discharge at the same state of charge in the first correspondence and the second correspondence as the open - circuit voltage difference; or, Determining the average value of the differences between the open - circuit voltages of charge and discharge at the same state of charge in the first correspondence and the second correspondence as the open - circuit voltage difference; 6. The method according to claim 5, wherein The determining the target state of charge based on the target open - circuit voltage and the first correspondence includes: If the open - circuit voltage difference is the difference between the open - circuit voltages of charge and discharge at the same state of charge, determining the target state of charge based on the target open - circuit voltage and the first correspondence; If the open-circuit voltage difference is the average value of the differences between the open-circuit voltages during charge and discharge at the same state of charge, based on the target open-circuit voltage and the third correspondence relationship, determine the target state of charge, where the third correspondence relationship is determined based on the average value of the differences between the open-circuit voltages during charge and discharge at the same state of charge in the first correspondence relationship and the second correspondence relationship.

7. The method according to any one of claims 1 to 6, characterized in that The method further includes: Determine whether there is a need to update the target open-circuit voltage; If there is a need to update the target open-circuit voltage, update the target open-circuit voltage; The determining the target state of charge based on the target open-circuit voltage and the first correspondence relationship includes: If there is no need to update the target open-circuit voltage, determine the target state of charge based on the target open-circuit voltage and the first correspondence relationship.

8. A state of charge determination device, characterized in that, The device includes: An acquisition module, configured to acquire the open-circuit voltage difference of the power battery when the vehicle is in a stationary state, where the open-circuit voltage difference is determined based on the first correspondence relationship between the state of charge and the open-circuit voltage in the discharge state and the second correspondence relationship between the state of charge and the open-circuit voltage in the charge state; A determination module, configured to, if the vehicle is in a driving state, determine the target voltage difference between the target correction coefficient in the current state and the open-circuit voltage difference, where the target correction coefficient is used to indicate the proportion of the open-circuit voltage difference when the vehicle is in a driving state to the open-circuit voltage difference when the vehicle is in a stationary state; A correction module, configured to correct the target voltage difference based on the target correction coefficient to obtain the target open-circuit voltage of the power battery; A calculation module, configured to determine the target state of charge based on the target open-circuit voltage and the first correspondence relationship.

9. A vehicle, characterized in that, The vehicle includes: A memory, configured to store executable program code; A processor, configured to call and run the executable program code from the memory, so that the vehicle executes the method for determining the state of charge according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which when executed, implements the method for determining the state of charge according to any one of claims 1 to 7.

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