Battery state estimation method and vehicle

Abstract

This application discloses a battery state estimation method and a vehicle, relating to the field of vehicle battery technology. The battery state estimation method includes: obtaining the duration for which the battery's discharge current is less than or equal to a preset current threshold; determining a first preset condition based on the duration and the current minimum battery voltage, and then determining a first reference state of charge and a second reference state of charge based on the battery temperature, the battery's maximum voltage, and the battery's minimum voltage; and finally determining the target battery state of charge based on the first and second reference states of charge. This battery state estimation method improves the accuracy of state of charge estimation by the battery management system under long-term low-current discharge conditions, thereby helping to prevent battery over-discharge.

Description

Technical Field

[0001] This application relates to the field of vehicle battery technology, and more specifically, to a battery state estimation method and a vehicle. Background Technology

[0002] With the increasing intelligence of vehicles, vehicle safety monitoring functions suitable for long-term low-current discharge conditions such as low-power standby, sleep / wake-up, emergency monitoring, and sentry mode have been widely used. For example, in sentry mode, after the vehicle is turned off and locked, some sensing and computing systems will continue to work, consuming battery power. The characteristics of this type of operation are very small discharge current and long duration, with the discharge current typically less than 1 ampere.

[0003] The Battery Management System (BMS) is typically responsible for process control under these operating conditions. One of its main functions is to estimate the battery's State of Charge (SOC) and State of Health (SOH) in real time. Current SOC estimation methods use the ampere-hour integration method, whose accuracy depends on the measurements from current sensors. However, under prolonged low-current conditions, the measurement error of conventional automotive current sensors increases significantly, leading to a continuous increase in the accumulated SOC deviation using the ampere-hour integration method, often resulting in an inflated SOC estimate. This inflated SOC may mask the true energy consumption, posing a risk of over-discharge. Simultaneously, the battery throughput (Ah) accumulated based on erroneous current data will also be biased, further distorting the SOH result calculated based on throughput. Summary of the Invention

[0004] This application provides a battery state estimation method and a vehicle to solve the problem of large deviation in the estimated SOC under long-term low-current discharge conditions of the vehicle. A large SOC deviation will also lead to a large deviation in the SOH calculated based on throughput.

[0005] To achieve the above technical objectives, the embodiments of this application provide the following technical solutions: In a first aspect, one embodiment of this application provides a battery state estimation method, including: The duration during which the battery's discharge current is less than or equal to a preset current threshold; If the first preset condition is met based on the duration and the current minimum battery voltage, a first reference state of charge and a second reference state of charge are determined according to the battery temperature, the maximum battery voltage, and the minimum battery voltage. The target battery state of charge is then determined based on the first reference state of charge and the second reference state of charge.

[0006] In conjunction with the first aspect, in some embodiments, the method further includes: determining the battery health state based on the cumulative throughput from the target battery state of charge to a fully charged battery and the target battery state of charge.

[0007] In this embodiment, by calculating the battery health state based on the target battery's state of charge and the cumulative throughput corresponding to the full charge state when the battery reaches full charge, a high-confidence estimation of SOH is achieved. Using full charge, an easily identifiable state node, as the calculation endpoint eliminates the error in determining the endpoint SOC; furthermore, anchoring the SOH calculation to a calibrated, reliable SOC starting point avoids the contamination of the SOH estimation results by historical throughput errors under long-term low-current discharge conditions, thereby improving the accuracy and stability of battery health state estimation.

[0008] In conjunction with the first aspect, in some embodiments, the process of obtaining the duration during which the battery's discharge current is less than or equal to a preset current threshold specifically includes: obtaining the high-voltage state time when the battery is in a high-voltage power-on state and the discharge current is less than or equal to the preset current threshold; obtaining the sleep time when the battery is in a low-power sleep state; and using the sum of the high-voltage state time and the sleep time as the duration.

[0009] In this embodiment, by adding the timing during the high-voltage power-on state to the timing during the low-power sleep state, the total time that the battery actually spends in a low-current consumption state can be more completely reflected. This avoids missing the continuous discharge time during the sleep period by only monitoring the power-on state, and ensures the accuracy of subsequent state of charge calibration condition judgment.

[0010] In conjunction with the first aspect, in some embodiments, the first preset condition includes: the duration is greater than the calibrated resting time, wherein the calibrated resting time is used to represent the time required for complete elimination of battery polarization; and the second reference state of charge obtained based on the battery minimum voltage value and the battery temperature by querying a preset correspondence is less than a preset state of charge threshold, wherein the preset correspondence is used to represent the correspondence between voltage, state of charge, and temperature.

[0011] In this embodiment, two prerequisites for initiating state of charge (SOC) calibration are defined. First, the duration must exceed the calibration resting time required for complete elimination of battery polarization. This ensures that the electrochemical state inside the battery tends to stabilize, and the voltage measured at this time more accurately reflects its SOC. Second, the second reference SOC obtained by querying a preset relationship must be less than a preset SOC threshold. This limits the calibration function to be activated within the SOC range where the calibration effect is significant in the voltage-SOC correspondence, thereby ensuring the effectiveness of calibration while preventing the introduction of new errors due to unreliable calibration in the middle of the voltage plateau region.

[0012] In conjunction with the first aspect, in some embodiments, determining the target battery state of charge based on the first reference state of charge and the second reference state of charge includes: determining the target battery state of charge based on the first reference state of charge when the first reference state of charge is less than a preset state of charge threshold.

[0013] In this embodiment, when the first reference state of charge (SOC) obtained from the battery's maximum voltage is less than a preset SOC threshold, the first reference SOC is directly used as the target battery SOC. This approach is suitable when the overall SOC of the current battery has entered a low-charge region suitable for calibration. It can quickly utilize a reliable voltage-SOC mapping relationship to complete SOC correction, thus improving the algorithm's execution efficiency.

[0014] In conjunction with the first aspect, in some embodiments, determining the target battery state of charge based on the first reference state of charge and the second reference state of charge includes: when the first reference state of charge is greater than or equal to a preset state of charge threshold and the second reference state of charge is less than a preset state of charge threshold, obtaining a first state of charge difference between the actual maximum state of charge and the actual minimum state of charge; and determining the target battery state of charge based on the sum of the differences between the second reference state of charge and the first state of charge.

[0015] In this embodiment, when the first reference state of charge (SOC) is greater than or equal to a preset SOC threshold, while the second reference SOC is less than the preset SOC threshold, a difference-preserving strategy is employed to determine the target battery SOC. This allows for maximum utilization of effective information when the battery SOC range is partially within the calibration effective region and partially within the ineffective region. By maintaining the actual estimated SOC range width unchanged and shifting based on an effective lower limit reference value, calibration information is absorbed while avoiding correction jumps that may occur due to unreliable partial voltage information, making the calibration process smoother.

[0016] In conjunction with the first aspect, in some embodiments, determining the target battery state of charge based on the first reference state of charge and the second reference state of charge includes: when the first reference state of charge is greater than or equal to a preset state of charge threshold, and the second reference state of charge is greater than or equal to the preset state of charge threshold, not performing calibration based on the first reference state of charge and the second reference state of charge, and not updating the target state of charge and keeping the current value of the target state of charge as the value of the previous moment.

[0017] This embodiment describes the handling method when both the first reference state of charge and the second reference state of charge exceed the applicable calibration threshold. In this case, the original estimated value of the actual maximum state of charge remains unchanged, thereby avoiding the introduction of potentially inaccurate corrections in the high state of charge range where the voltage-state of charge relationship is flat and the calibration reference value is not high, thus ensuring the reliability of the algorithm in the high state of charge range.

[0018] In conjunction with the first aspect, in some embodiments, the method further includes: when the discharge current of the battery is greater than the preset current threshold, determining the battery health status based on the cumulative throughput from the target battery state of charge to the battery fully charged and the target battery state of charge.

[0019] In this embodiment, when the battery current is detected to have recovered to a larger value (i.e., exiting the low-current operating condition), the system immediately locks the currently calibrated target battery state of charge as the starting point for subsequent battery health state calculations and simultaneously resets the cumulative throughput. By completing the benchmark locking immediately upon exiting the low-current operating condition, data preparation is made for subsequent battery health state calculations during full charging, ensuring that battery health state information can be updated promptly after the first complete charging cycle, thus improving the timeliness and accuracy of battery health state estimation.

[0020] In conjunction with the first aspect, in some embodiments, the method further includes: when the duration is greater than a first time threshold and less than a calibrated resting time, using a preset state of charge as the target battery state of charge, wherein the preset state of charge is a value exceeding the normal range of 0% to 100%, and resetting the historical cumulative throughput to zero.

[0021] In this embodiment, by setting the target state of charge to an abnormal value and clearing the historical cumulative throughput, this unreliable data segment is actively identified and isolated, thereby preventing this operating condition data, which is insufficient to completely eliminate polarization due to its long duration and small current, from contaminating the subsequent cumulative charge benchmark used to calculate the battery health status.

[0022] In conjunction with the first aspect, in some embodiments, the method further includes: determining the battery health state based on the ratio of the cumulative throughput to the second state of charge difference when the second state of charge difference between the fully charged state of charge and the target battery state of charge is greater than a preset state of charge threshold.

[0023] In this embodiment, the difference between the fully charged state of charge and the target state of charge starting point must be greater than a preset state of charge threshold before calculation is performed. This utilizes a larger range of charge variation to reduce the impact of relative error in cumulative throughput measurement on the final battery health state calculation result, thereby improving the accuracy of battery health state calculation.

[0024] Secondly, one embodiment of this application also provides a vehicle including a memory and a processor, the memory storing a computer program, the processor executing the computer program to implement the battery state estimation method as described above.

[0025] As can be seen from the above technical solution, the vehicle provided in this application embodiment implements the battery state estimation method described in the first aspect. This method accurately identifies whether the vehicle is in a long-term low-current discharge condition by obtaining the duration during which the battery discharge current is less than or equal to a preset current threshold. Based on this, it determines whether a first preset condition is met based on the duration and the current minimum battery voltage. This first preset condition indicates that the battery has entered a state where the voltage-temperature-state of charge mapping relationship is available. When the condition is met, the system determines a first reference state of charge and a second reference state of charge based on the battery temperature, the maximum battery voltage, and the minimum battery voltage, respectively, and calculates the target battery state of charge based on the combined calculation of the two. Without relying on additional hardware, it effectively corrects the accumulated SOC deviation caused by insufficient accuracy of the current sensor under low current conditions. At the same time, by introducing the dual criteria of duration and minimum voltage as calibration trigger conditions, it ensures that the calibration behavior is only performed within the operating window where the voltage is reliable and the mapping is effective. Thus, this technical solution solves the problem of large SOC estimation deviation under long-term low-current discharge conditions of the vehicle, improves the accuracy of state of charge estimation of the battery management system under special operating conditions, and helps to prevent battery over-discharge. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0027] Figure 1 A flowchart of a battery state estimation method provided in one embodiment of this application.

[0028] Figure 2 for Figure 1 The voltage-temperature-charge mapping used in the battery state estimation method is shown as a schematic representation.

[0029] Figure 3 This is a schematic diagram of the architecture of a vehicle provided for one embodiment of this application. Detailed Implementation

[0030] Unless otherwise defined, the technical or scientific terms used in the embodiments of this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to avoid confusion of the constituent elements.

[0031] Unless the context otherwise requires, throughout this specification, "a plurality of" means "at least two," and "including" is interpreted as open-ended or encompassing, that is, "including, but not limited to." In the description of this specification, terms such as "one embodiment," "some embodiments," "exemplary embodiment," "example," "specific example," or "some examples" are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this application. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example.

[0032] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0033] Overview In the current development of vehicle intelligence, functions such as sentry mode and remote monitoring, which require maintaining the operation of some systems for extended periods while the vehicle is stationary, have become mainstream features. The realization of these functions relies on the vehicle's power battery providing a low current for an extended period during the resting period, thus necessitating a conflict between high-precision state estimation methods and ultra-low power continuous discharge scenarios.

[0034] For estimating the state of charge (SOC) of vehicle batteries, the ampere-hour integration method is a commonly used approach, its accuracy relying on high-precision current sampling. For estimating the state of health (SOC), many capacity-based methods relate to the cumulative throughput of the battery over a complete charge-discharge cycle, with initial data also derived from current sampling. Under conditions of high current, such as vehicle driving or charging, the relative measurement error of mainstream current sensors can be controlled at a low level, allowing existing methods to work effectively.

[0035] However, under prolonged low-current operating conditions, the battery discharge current typically stabilizes below 1 amp, and may even be as low as several hundred milliamps. While the error of the current sensor at this low range may be small, its relative error can become significant. Furthermore, the duration of these prolonged low-current operating conditions can last for hours or even days, causing the SOC integral deviation due to current sampling errors to accumulate continuously. This ultimately leads to a significant deviation in the estimated SOC, often appearing artificially high. An artificially high SOC not only misleads users about their remaining range but also masks the true energy consumption, causing the battery to be over-discharged without the user's knowledge, thus damaging the battery's lifespan and even posing safety hazards. Simultaneously, throughput data based on accumulated error current loses its accuracy; using it for SOH calculations will also result in distorted results, failing to provide a reliable basis for battery lifespan prediction and value assessment.

[0036] Therefore, the technical problem faced in this field under long-term low-current operating conditions of vehicles can be defined as: how to reduce the estimation deviation of SOC and SOH of the battery under long-term low-current discharge conditions.

[0037] To address the aforementioned technical challenges, this application proposes further research into how to better utilize current signals in scenarios where vehicle operation under prolonged low-current conditions is inherently limited. Specifically, it explores the possibility of temporarily eliminating reliance on current signals under specific conditions and finding other reliable information sources to reconstruct the baseline for state estimation. During prolonged low-current discharge, the battery load is stable and minimal. After a sufficiently long resting period, the polarization voltage generated within the battery due to historical operating conditions will stabilize sufficiently. At this point, the battery's closed-circuit voltage (CCV) will approach its equilibrium open-circuit voltage (OCV) and exhibit stable changes with energy consumption. Therefore, under prolonged low-current conditions in vehicles, a stable and predictable mapping relationship exists between voltage and state of charge (SOC). If this relationship can be precisely calibrated experimentally beforehand, a high-precision SOC reference value can be obtained by reverse-looking up a table during actual vehicle operation by measuring voltage and temperature in real time, thus completely bypassing the dependence on inaccurate current integration.

[0038] Of course, the effectiveness of this calibration strategy depends on two prerequisites: first, ensuring that the battery has indeed reached a quasi-static state, i.e., polarization has been fully eliminated; second, ensuring that the current SOC point of the battery is located in the sensitive segment of the voltage-SOC relationship, which is not a plateau region. The former can be judged by a resting time longer than the OCV; the latter is determined by setting an applicable threshold (SOC) based on the battery chemistry. up Calibration is only performed when the SOC obtained from the table lookup is lower than this threshold.

[0039] When the vehicle exits its long-term low-current operating condition—that is, when the battery discharge current is determined to be less than or equal to a preset current threshold—the system locks the target battery's state of charge (SOC) as the starting point for calculating the battery's health status and performs a zeroing operation on the accumulated throughput. Subsequently, the system calculates the health status based on the battery throughput re-accumulated from this starting point, effectively reducing the relative error in the accumulated throughput measurement and thus obtaining a high-precision battery health status value.

[0040] In summary, the technical solution of this application aims to solve the estimation deviation problem through the following process: First, monitor the duration of the battery discharge current and determine whether a reliable calibration state has been entered by combining the voltage information; second, in this state, calibrate the state of charge based on the battery's voltage and temperature parameters to correct the cumulative error caused by long-term low-current discharge; subsequently, when the battery exits the low-current state, set the calibrated state of charge as a new benchmark for calculating the health state, thereby ensuring the accuracy of the initial data for subsequent calculations; finally, when the battery reaches a fully charged state and the change in charge is sufficiently significant, calculate a high-precision battery health state value based on the reliable charge data accumulated from the new benchmark.

[0041] Exemplary methods One embodiment of this application provides a battery state estimation method, which is typically executed periodically as a task in the application layer software of a battery management system. Figure 1 A flowchart illustrating the battery state estimation method provided in this application embodiment. See also... Figure 1 The battery state estimation method in this application embodiment may include the following steps: Step S101: Obtain the duration during which the battery discharge current is less than or equal to a preset current threshold.

[0042] The battery management system continuously samples the total current I of the battery pack. bat Set a preset current threshold I th The system runs a timer, which detects when the current is less than or equal to a preset current threshold I. th When |I is in the state, the timer increments; if |I bat |Greater than I th The timer will pause or reset. Preset current threshold I. th The range is from 0.8 amps to 1 amp, preferably 1 amp. When the battery pack current |I is detected... bat |Continuously greater than or equal to the preset threshold I th When the vehicle has exited the long-term low-current discharge condition, it is considered to have exited the long-term low-current discharge condition.

[0043] The accumulated time of this timer is the initial high-voltage state time. The complete duration of the state where the current is less than or equal to the preset current threshold also includes the stage where the vehicle network enters deep sleep mode. The battery management system can obtain the sleep time directly from the body domain controller or gateway via the vehicle's CAN network. Therefore, the duration of the state where the current is less than or equal to the preset current threshold = accumulated high-voltage state time + obtained sleep time.

[0044] Step S102: If the first preset condition is met based on the duration and the current minimum battery voltage, determine the first reference state of charge and the second reference state of charge according to the battery temperature, the maximum battery voltage and the minimum battery voltage, and determine the target battery state of charge based on the first reference state of charge and the second reference state of charge.

[0045] The system first determines whether to initiate state-of-charge calibration based on whether a first preset condition is met. This first preset condition is specifically set based on the duration and the current minimum battery voltage. After determining that the first preset condition is met, the system performs the following operations to obtain calibration reference values: Obtain the maximum battery voltage during the low-current discharge phase and reconfirm the current battery temperature.

[0046] Based on the battery's maximum voltage and temperature, and through the known mapping relationship between voltage, temperature, and charge state, the first reference state of charge (CCV-SOC) is obtained. max Based on the minimum battery voltage and battery temperature, and through the known mapping relationship between voltage, temperature, and state of charge, a second reference state of charge (CCV-SOC) is obtained. min ).

[0047] Thus, the system has obtained two key reference values: the first reference state of charge and the second reference state of charge, which are theoretical SOC values ​​mapped at a given temperature based on the highest and lowest voltages observed during low-current discharge.

[0048] The system determines the final target battery state of charge for updating based on the first and second reference states of charge and a preset state of charge threshold.

[0049] This embodiment accurately identifies whether a vehicle is in a long-term low-current discharge condition by acquiring the duration for which the battery discharge current is less than or equal to a preset current threshold. Based on this, it determines whether a first preset condition is met based on the duration and the current minimum battery voltage. This first preset condition indicates that the battery has entered a state where the voltage-temperature-state-of-charge (SOC) mapping relationship is usable. When the condition is met, the system determines a first reference SOC and a second reference SOC based on the battery temperature, maximum battery voltage, and minimum battery voltage, respectively, and calculates the target battery SOC based on a comprehensive calculation of both. Without relying on additional hardware, this effectively corrects the accumulated SOC deviation caused by insufficient current sensor accuracy under low current conditions. Simultaneously, by introducing duration and minimum voltage as dual criteria for calibration triggering, it ensures that calibration is performed only within a working window where the voltage is reliable and the mapping is effective. Therefore, this technical solution solves the problem of large SOC estimation deviations under long-term low-current discharge conditions, improves the accuracy of SOC estimation by the battery management system under special conditions, and helps prevent battery over-discharge.

[0050] In some optional embodiments, the method further includes determining the battery health status based on the cumulative throughput from the target battery state of charge to full charge and the target battery state of charge.

[0051] In this embodiment, assuming the data obtained in step S102 is reliable, the battery capacity degradation is evaluated using the power data within a complete charging cycle. The specific implementation process is as follows: The system continuously monitors the battery status and determines whether the conditions for performing a State of Health (SOH) calculation are met. Preferably, the conditions include the following two items, which must be met simultaneously: The system has detected that the battery has reached a fully charged state. This is typically determined by one or a combination of several commonly used BMS criteria, such as the total battery pack voltage reaching the full charge voltage threshold, the individual cell voltage reaching the upper limit, or the charging current dropping to the cutoff current, to ensure the reliability of the determination of the fully charged state node.

[0052] The system calculates the change in charge from the target battery's state of charge to 100% full charge, and determines whether this change exceeds a preset effective threshold. This threshold is set to ensure that the range of charge change used to calculate SOH is sufficiently large, thereby reducing potential relative errors in cumulative throughput measurement and improving the accuracy of the final SOH result.

[0053] The subsequent SOH calculation process is only triggered when the system confirms that the battery is fully charged and the change in charge from the target SOC starting point to full charge is greater than the effective change threshold.

[0054] Cumulative throughput refers to the cumulative battery charge and discharge ampere-hours (Ah) from the moment corresponding to the target battery state of charge (i.e., the moment when the battery exits the long-term low-current operating condition and this value is locked as the starting point) until the current full charge state.

[0055] The change in SOC during the charging process from the starting point of the target battery charge to the state of full charge is a value ranging from 0 to 1.

[0056] Once the triggering conditions are met and the data is ready, the system performs a battery state of health (SOH) calculation. An exemplary implementation of this calculation is as follows: The State of Health (SOH) value of the battery is calculated using the following formula: Q max =Cumulative throughput / Change in full charge capacity SOH=Q max / Q rated ×100% Among them, Q max Q represents the battery's current maximum usable capacity (Ah). rated This refers to the battery's rated capacity (Ah).

[0057] This formula calculates the ratio of the actual amount of electricity charged into the battery during the current charging cycle to its theoretical maximum chargeable capacity from the initial state of charge (SOC) to full charge. This ratio directly reflects the battery's current usable capacity retention rate relative to its initial rated capacity, i.e., its state of health. The calculated battery health status value is typically in the range of 0% to 100%. The system updates this calculation result to the current battery health status value for use in battery management strategies, lifespan prediction, and status display.

[0058] In summary, by calculating the battery health state (SOH) based on the target battery's state of charge (SOC) and the cumulative throughput corresponding to the full charge state when the battery reaches full charge, a high-confidence estimation of SOH is achieved. Using full charge, an easily identifiable state node, as the calculation endpoint eliminates the error in determining the endpoint SOC. Furthermore, anchoring the SOH calculation to a calibrated, reliable SOC starting point avoids the contamination of the SOH estimation results by historical throughput errors under long-term low-current discharge conditions, thereby improving the accuracy and stability of battery health state estimation.

[0059] In some optional embodiments, obtaining the duration during which the battery's discharge current is less than or equal to a preset current threshold specifically includes: obtaining the high-voltage state time when the battery is in a high-voltage power-on state and the discharge current is less than or equal to the preset current threshold; obtaining the sleep time when the battery is in a low-power sleep state; and using the sum of the high-voltage state time and the sleep time as the duration.

[0060] Specifically, this embodiment obtains the duration during which the battery's discharge current is less than or equal to a preset current threshold in the following manner to ensure the integrity of the total time the battery is actually in a low-current consumption state: 1. Obtain the high-voltage state time when the battery is in a high-voltage power-on state and the discharge current is less than or equal to a preset current threshold.

[0061] The high-voltage state time refers to the cumulative duration during which the battery pack's high-voltage main relay is closed, the battery is in a high-voltage powered-on state capable of outputting power, and the real-time monitored battery pack discharge current remains less than or equal to a preset current threshold. For example, the preset current threshold is calibrated as 1A.

[0062] During each high-voltage power-on period, the system maintains a high-voltage state timer. This timer begins to accumulate when both conditions are met simultaneously: the high-voltage main relay is closed and the battery pack current is less than or equal to a preset current threshold. When the battery pack current exceeds the preset current threshold, the timer is immediately reset to zero; when the high-voltage main relay is open, the timer retains its current value. Upon the next closure of the high-voltage main relay, if the battery pack current is less than or equal to the preset current threshold, the timer continues to accumulate; if the battery pack current exceeds the preset current threshold, the timer is reset to zero. This logic ensures that the recorded high-voltage state time strictly corresponds to the total duration of the high-voltage operating condition segment with the target low-current discharge, avoiding time loss due to brief relay disconnections.

[0063] 2. Obtain the sleep time when the battery is in a low-power sleep state.

[0064] Sleep time refers to the duration after the vehicle or battery management system enters a low-power sleep state. In this state, the high-voltage main relay is disconnected, and the battery maintains the minimum monitoring functions of the battery management system with a small current. The sleep time can be read directly from the battery management system's underlying software or hardware real-time clock module. The system records a timestamp each time it enters sleep mode, and retrieves the current timestamp when it is woken up next time; the difference between the two is the sleep time for this sleep mode. This time is an objective accumulation of physical time and does not require conditional judgment and zeroing like the high-voltage state time. This part of the time records the duration of the small current consumption of the battery due to self-discharge and maintaining basic monitoring when the vehicle is completely idle or running without any active functions.

[0065] 3. The sum of the high-pressure state time and the dormancy time is taken as the duration.

[0066] The system directly adds the high-voltage state time to the sleep time, and the sum is the duration.

[0067] Both the active low-current discharge under high voltage and the static micro-consumption under dormancy conditions fall under the category of long-term low-current discharge. Adding these two periods together fully covers all stages during which the battery may experience low-current losses while the vehicle is parked, thus providing an accurate total time reference for subsequently determining whether battery polarization has been sufficiently eliminated and whether the state of charge calibration conditions have been met.

[0068] In this embodiment, by adding the timing during the high-voltage power-on state to the timing during the low-power sleep state, the total time that the battery actually spends in a low-current consumption state can be more completely reflected. This avoids missing the continuous discharge time during the sleep period by only monitoring the power-on state, and ensures the accuracy of subsequent state of charge calibration condition judgment.

[0069] In some optional embodiments, the first preset condition includes: the duration is greater than the calibrated resting time, wherein the calibrated resting time is used to represent the time required for complete elimination of battery polarization; and the second reference state of charge obtained by querying a preset correspondence based on the minimum battery voltage value and battery temperature is less than a preset state of charge threshold, wherein the preset correspondence is used to represent the correspondence between voltage, state of charge and temperature.

[0070] Specifically, the first preset condition is crucial for determining whether and when the voltage-temperature-based state of charge calibration function can be activated. Its implementation includes the following two sub-conditions that must be met simultaneously: 1. The duration is longer than the calibrated settling time.

[0071] This condition aims to ensure the stability of the battery's internal electrochemical state, so that the measured terminal voltage can effectively reflect its true open-circuit voltage. The calibration resting time is a predetermined minimum time value required to characterize a specific battery under minimal or no current conditions, allowing its internal polarization voltage to sufficiently decay to a negligible level. This time value is typically determined experimentally by the battery manufacturer and integrated into the calibration data of the battery management system as a key characteristic parameter of the battery.

[0072] The system compares the real-time calculated or acquired duration with the calibrated resting time. If the duration exceeds the calibrated resting time, the battery is considered to have undergone a sufficiently long resting period, and its terminal voltage is largely unaffected by transient polarization caused by the previous charge-discharge history. The voltage reading obtained at this time is stable and reliable, suitable as an input signal for calibrating the state of charge. If this condition is not met, it indicates that the battery has not yet reached a quasi-equilibrium state, the voltage information may be distorted, and calibration should not be performed.

[0073] 2. The second reference state of charge is less than the preset state of charge threshold.

[0074] This condition aims to limit the state-of-charge (SOC) calibration function to a specific operating range with high calibration accuracy, avoiding the introduction of errors in inapplicable ranges. The preset correspondence is a three-dimensional voltage-SOC-temperature mapping database, which is pre-established by recording the stable closed-circuit voltage of the battery at different temperatures and SOC points under specific small constant current (e.g., 1A) discharge conditions through laboratory testing.

[0075] During operation, the system acquires the minimum battery voltage and corresponding battery temperature measured during the current low-current operating phase, and uses this as input to query a preset correspondence. The result of the query is the second reference state of charge, which represents the theoretical limit of the battery's possible state of charge when the minimum voltage value is observed at the current temperature.

[0076] The system compares the retrieved second reference state of charge (SOC) with a preset SOC threshold. This threshold is set based on the battery chemistry; for example, it can be set to 25% for lithium iron phosphate batteries with a very flat voltage plateau, and to 100% for ternary lithium batteries with a steeper voltage curve. The battery's SOC is considered to be within the applicable and valid range for this calibration method only if the second reference SOC is lower than this threshold, typically the region with a steeper voltage-SOC curve. If the second reference SOC is greater than or equal to this threshold, it indicates that the battery may be in a voltage plateau region with minimal voltage variation, failing to provide effective SOC resolution information, and therefore calibration is not enabled.

[0077] In summary, this embodiment clarifies two prerequisites for initiating state of charge (SOC) calibration. First, the duration must exceed the calibration resting time required for complete elimination of battery polarization. This ensures that the electrochemical state inside the battery tends to stabilize, and the voltage measured at this time more accurately reflects its SOC. Second, the second reference SOC obtained by querying a preset relationship must be less than a preset SOC threshold. This limits the calibration function to be activated within the SOC range where the calibration effect is significant in the voltage-SOC correspondence, thereby ensuring the effectiveness of calibration while preventing unreliable calibration in the middle of the voltage plateau region from introducing new errors.

[0078] In some optional embodiments, determining the target battery state of charge based on a first reference state of charge and a second reference state of charge includes: determining the target battery state of charge based on the first reference state of charge when the first reference state of charge is less than a preset state of charge threshold.

[0079] Specifically, the system first confirms that the first preset condition is met, thus entering the state of charge (SOC) calibration process. Based on this, the system further obtains a first reference SOC obtained by querying a preset correspondence between the battery's maximum voltage and current battery temperature. The system then determines whether this first reference SOC is also less than a preset SOC threshold. When the first reference SOC is determined to be less than the preset SOC threshold, the system directly identifies the first reference SOC as the target battery SOC and uses this target battery SOC value to overwrite or correct the SOC estimate currently maintained in the battery management system, completing this calibration update.

[0080] Here, when the first reference state of charge is less than a preset threshold, it means that even the estimated state of charge corresponding to the cell with the highest voltage is below the calibration threshold. This indicates that the entire battery pack is in a region where polarization is sufficiently eliminated and the voltage changes significantly with decreasing state of charge. In this state, the first reference state of charge obtained from the table based on the maximum battery voltage has high confidence.

[0081] In this embodiment, when the first reference state of charge (SOC) obtained from the battery's maximum voltage is less than a preset SOC threshold, the first reference SOC is directly used as the target battery SOC. This approach is suitable when the overall SOC of the current battery has entered a low-charge region suitable for calibration. It can quickly utilize a reliable voltage-SOC mapping relationship to complete SOC correction, thus improving the algorithm's execution efficiency.

[0082] In some optional embodiments, determining the target battery state of charge based on a first reference state of charge and a second reference state of charge includes: when the first reference state of charge is greater than or equal to a preset state of charge threshold and the second reference state of charge is less than the preset state of charge threshold, obtaining a first state of charge difference between the actual maximum state of charge and the actual minimum state of charge; and determining the target battery state of charge based on the sum of the differences between the second reference state of charge and the first state of charge.

[0083] Specifically, the system first confirms that the first preset condition is met, thus entering the state of charge (SOC) calibration process. Based on this, the system further obtains a first reference SOC obtained by querying a preset correspondence between the battery's maximum voltage and current battery temperature, and performs the following judgment: if the first reference SOC is greater than or equal to a preset SOC threshold and the second reference SOC is less than the preset SOC threshold, then the system determines that the current battery is in a partially valid calibration range—that is, the lower limit of the battery's SOC estimation range has fallen into the valid calibration range, while the upper limit is still in the voltage plateau region or the invalid calibration region. In this scenario, a difference preservation strategy must be adopted.

[0084] The system reads the state-of-charge (SOC) estimation variables maintained internally by the current battery management system, including the actual maximum SOC. max Actual minimum state of charge (SOC) min The actual maximum state of charge (PSC) refers to the currently estimated PSC value of the highest-voltage individual cell in the battery pack, usually given by the highest-voltage individual cell or a comprehensive algorithm; the actual minimum state of charge (PSC) refers to the currently estimated PSC value of the lowest-voltage individual cell in the battery pack, usually given by the lowest-voltage individual cell or a comprehensive algorithm.

[0085] The system calculates the difference between the actual maximum state of charge and the actual minimum state of charge, which is taken as the first state of charge difference (ΔSOC). The calculation formula is as follows: ΔSOC=SOC max -SOC min The first state-of-charge difference characterizes the degree of inconsistency in the estimated state of charge between individual cells within the current battery pack, and is also a key parameter for the battery management system to maintain the range of state-of-charge estimation.

[0086] Next, the system performs the following calculations to determine the target battery state of charge (SOC). target ): With the second reference state of charge (CCV-SOC) min This will serve as the new lower limit benchmark value. The first state of charge difference (ΔSOC) is superimposed on this lower limit reference value; The sum obtained is determined as the target battery state of charge, i.e.: SOC target =CCV-SOC min +ΔSOC The system updates the master estimate of the state of charge in the current battery management system with the target battery state of charge value, while keeping the difference width between the actual maximum state of charge and the actual minimum state of charge unchanged.

[0087] In summary, in this embodiment, when the first reference state of charge (SOC) is greater than or equal to a preset SOC threshold, while the second reference SOC is less than the preset SOC threshold, a difference-preserving strategy is employed to determine the target battery SOC. This maximizes the utilization of effective information when the battery SOC range is partially within the calibration effective region and partially within the ineffective region. By maintaining the actual estimated SOC range width unchanged and shifting based on an effective lower limit reference value, calibration information is absorbed while avoiding correction jumps that may occur due to unreliable partial voltage information, making the calibration process smoother.

[0088] In some optional embodiments, determining the target battery state of charge based on a first reference state of charge and a second reference state of charge includes: if the first reference state of charge is greater than or equal to a preset state of charge threshold and the second reference state of charge is greater than or equal to the preset state of charge threshold, then no calibration is performed based on the first reference state of charge and the second reference state of charge, and the target state of charge is not updated and the current value of the target state of charge is kept as the value of the previous time step.

[0089] Specifically, the system first confirms that the first preset condition is met, thus entering the state of charge calibration process. However, during the further execution of the specific calibration determination, the system detects the following situation: The first reference state of charge obtained by querying the preset correspondence between the battery's maximum voltage value and the current battery temperature is greater than or equal to the preset state of charge threshold; and the second reference state of charge obtained by querying the preset correspondence between the battery's minimum voltage value and the current battery temperature is also greater than or equal to the preset state of charge threshold.

[0090] At this point, the system determines that the current battery is in a state of invalid calibration across the entire range—that is, the estimated range of the battery's state of charge (SOC) lies entirely within a range where the voltage-charge relationship is flat or the calibration method is inapplicable. In this scenario, the sensitivity of voltage to changes in SOC is very low, and any reference SOC obtained based on voltage lookup tables lacks sufficient confidence.

[0091] Based on the above determination, the system does not perform calibration based on the first and second reference states of charge (SOC), and does not update the target SOC, maintaining its current value as it was at the previous time step. This target SOC refers to the current battery pack SOC value maintained in real-time by the battery management system during the regular estimation process, such as the actual maximum SOC. The system does not make any corrections or adjustments to this target battery SOC, but instead passes it as the output value of this step to subsequent processes.

[0092] In summary, this embodiment describes a handling method when both the first reference state of charge and the second reference state of charge exceed the applicable calibration threshold. In this case, the original estimated value of the actual maximum state of charge remains unchanged, thereby avoiding the introduction of potentially inaccurate corrections in the high state of charge range where the voltage-state of charge relationship is flat and the calibration reference value is not high, thus ensuring the reliability of the algorithm in the high state of charge range.

[0093] In some optional embodiments, the above method further includes: when the battery discharge current is greater than a preset current threshold, determining the battery health status based on the cumulative throughput from the target battery state of charge to the battery when it is fully charged and the target battery state of charge.

[0094] Specifically, the system continuously monitors the battery's discharge current value. If the system detects that the battery's discharge current is greater than the preset current threshold (for example, the preset current threshold is 1A, and the current rises to 1.1A, 2A, or higher), it determines that the battery has exited the state where the discharge current is less than or equal to the preset current threshold (i.e., it has exited the long-term low-current discharge condition).

[0095] In this scenario, regardless of whether the battery is charging or fully charged, the system immediately triggers a battery health status calculation or update process. When the above conditions are met, the system locks the current target battery state of charge value, which becomes the starting point for the charge change in this battery health status calculation. Simultaneously, the system reads the re-accumulated battery throughput data (Ah) from the critical point of exiting the low-current operating condition to the current trigger time. It should be noted that if the battery has not undergone a complete charging process after exiting the low-current operating condition, the accumulated throughput may be partial charging capacity, partial discharging capacity, or the algebraic sum of both. The system obtains the accumulated throughput (Q) up to the current time based on the actual operating conditions. acc ).

[0096] The system calculates the current state of charge (SOC) of the battery. current ) and target battery state of charge (SOC) target The difference between these values ​​is used as the capacity change window for this battery health status calculation. ΔSOC=SOC current -SOC target Wherein, ΔSOC is the change in SOC, and its value range is 0≤ΔSOC≤1.

[0097] The system performs SOH calculation based on the above data. An exemplary implementation is as follows: Calculation formula: The battery health status value is calculated using the following formula: SOH=(Q acc / (ΔSOC×Q rated ))×100% Among them, Q rated The rated capacity of the battery (Ah); ΔSOC×Q rated Q represents the theoretical amount of electricity from the starting point to the current state; acc This represents the cumulative throughput.

[0098] The calculation result ranges from 0% to 100%, and is updated to the current health status value of the battery, which is used for battery management system policy adjustment, instrument display, and cloud monitoring.

[0099] In summary, in this embodiment, when the battery current is detected to have recovered to a larger value (i.e., exiting the low-current operating condition), the system immediately locks the currently calibrated target battery state of charge as the starting point for subsequent battery health state calculations and simultaneously resets the cumulative throughput. By completing the benchmark locking immediately upon exiting the low-current operating condition, data preparation is made for subsequent battery health state calculations during full charging, ensuring that battery health state information is updated promptly after the first complete charging cycle, thus improving the timeliness and accuracy of battery health state estimation.

[0100] In some optional embodiments, the above method further includes: when the duration is greater than a first time threshold and less than a calibrated resting time, using a preset state of charge as the target battery state of charge, wherein the preset state of charge is a value that exceeds the normal range of 0% to 100%, and resetting the historical cumulative throughput to zero.

[0101] The system continuously monitors the battery's duration. If the duration exceeds a first time threshold but is less than the calibrated resting time, the system determines that the small current discharge duration has accumulated to a point where the ampere-hour integration error is not negligible (exceeding the first time threshold), but the condition for reliable voltage-based calibration has not yet been met (the calibrated resting time has not been met). Within this window, the cumulative throughput data begins to deviate significantly from the true value, and voltage-based state-of-charge calibration is not feasible due to incomplete polarization elimination.

[0102] To address this, the system pre-configures a state of charge (SOC) value exceeding the normal range of 0% to 100% as an invalid data marker; for example, it could be set to 110% (higher than a full charge). The system then forcibly sets the target battery SOC at the current moment to this value, overwriting the previously maintained SOC estimate in the battery management system. Simultaneously, the system forcibly resets the cumulative throughput counter maintained in the battery management system to zero, clearing all historical cumulative throughput data from the start of this low-current operation to the current moment. After resetting, subsequent cumulative throughput will be recalculated starting from the current moment, while previous throughput data is completely erased and no longer participates in any subsequent calculations.

[0103] Since historical throughput has been cleared and the abnormal state of charge starting point will not be used for battery health calculation, the throughput re-accumulated from that moment will be associated with a valid future calibration point, thus ensuring that the data used for battery health calculation is always clean.

[0104] In summary, in this embodiment, by setting the target state of charge to an outlier value and clearing the historical cumulative throughput, this unreliable data segment is actively identified and isolated. This prevents the data segment, which is insufficient to completely eliminate polarization due to its long duration and has a small current leading to significant measurement errors, from contaminating the cumulative charge benchmark used to calculate the battery health status.

[0105] In some optional embodiments, the method further includes: determining the battery health status based on the ratio of cumulative throughput to the second state of charge difference when the second state of charge difference between the fully charged state of charge and the target battery state of charge is greater than a preset state of charge threshold.

[0106] Specifically, the system continuously monitors the battery status, and when it detects that the battery has reached full charge and exits the low-current operating condition, it locks in a valid target battery state of charge (SOC). target If the value is within the normal range of 0% to 100% and is not marked as an outlier, then a validity verification of the power change window is performed. Here, the criteria for full charge can include: the total battery pack voltage reaching the full charge cutoff voltage, any single cell voltage reaching the charging upper limit, the charging current dropping to the constant voltage stage cutoff current, or the BMS confirming that the battery is fully charged through a multi-source fusion algorithm. Full charge status is one of the easiest operational nodes for the BMS to accurately determine, possessing a high degree of confidence.

[0107] The validity verification of the power change window is performed as follows: Using the formula ΔSOC full =100%-SOC target Calculate the second state of charge difference (ΔSOC). full This refers to the state of charge (SOC) at the moment of full charge and the target battery SOC. target The difference between ) represents the width of the theoretical charge change range experienced from the calibrated state of charge value locked when exiting low current operation to the moment of full charge.

[0108] The system is pre-configured with a preset state of charge threshold, for example, it can be set to 50%, 30% or dynamically adjusted according to battery characteristics.

[0109] The system will calculate the second state of charge difference ΔSOC. full Compare with a preset state of charge threshold: If ΔSOC full If a preset state of charge threshold is set, the current charge change window is deemed valid, and SOH calculation is allowed. If ΔSOC full If the value is less than or equal to the preset state of charge threshold, the current charge change window is determined to be too small, and the SOH calculation is rejected.

[0110] When ΔSOC full When the condition is met (greater than a preset threshold), the system reads the target battery's state of charge (SOC). target From the moment the battery was locked until the moment it was fully charged, the newly accumulated throughput (Q) acc (Ah), and calculate the battery health status using the following formula: SOH=Q acc / (ΔSOC full ×Q rated )×100% Among them, Q acc For cumulative throughput, Q rated The rated capacity (Ah) of the battery is given, and the SOH value is in the range of 0% to 100%.

[0111] In summary, in this embodiment, the difference between the fully charged state of charge and the target state of charge starting point must be greater than a preset state of charge threshold before calculation is performed. This utilizes a larger range of charge variation to reduce the impact of relative error in cumulative throughput measurement on the final battery health state calculation result, thereby improving the accuracy of battery health state calculation.

[0112] In some optional embodiments, the applicable calibration threshold is set according to the battery chemistry system; for lithium iron phosphate batteries, the applicable calibration threshold is no higher than 30%; for ternary lithium batteries, the applicable calibration threshold is no lower than 95%.

[0113] In this embodiment, the adaptation to the characteristics of the battery cell material is further defined. Specifically, lithium iron phosphate batteries have a very flat voltage plateau in the medium SOC range (approximately 20%-80%). Within this range, the rate of voltage change with SOC is very low, and even small voltage measurement noise can lead to a large SOC lookup table error. Therefore, the SOC of the lithium iron phosphate battery is... up The preferred setting is 25%, and it is generally set within the range of no more than 30%. This means that voltage lookup calibration is only allowed in the low SOC region, thus actively avoiding the risk of operating in the ineffective plateau region. Ternary lithium batteries have good monotonicity in their voltage-SOC curves and are relatively sensitive to voltage changes across the entire SOC range; therefore, their SOC... up It can be set to 100%, and calibration is usually performed within a range of no less than 95%, allowing for flexible calibration across the entire range.

[0114] In some optional embodiments, the establishment of the pre-stored voltage-temperature-charge mapping table includes: performing a discharge experiment on the battery with a constant current of the same preset current threshold under multiple different ambient temperature conditions; collecting the battery's voltage, temperature, and corresponding real-time state of charge data during the discharge experiment; and forming a correspondence between voltage, temperature, and state of charge based on the collected data.

[0115] The mapping table is designed to accurately simulate the vehicle's discharge conditions in sentry mode to obtain the correspondence between voltage (V), temperature (T), and state of charge (SOC). The steps for establishing this mapping table are as follows: STEP1: Perform a discharge experiment on the battery under multiple different ambient temperature conditions with a constant current that is the same as the preset current threshold.

[0116] Specifically, to comprehensively cover the temperature environments the vehicle might operate in, the experiment was conducted under multiple different ambient temperature conditions. The selected temperature range should cover the battery's operating temperature range, for example, -20℃, -10℃, 0℃, 10℃, 25℃, 40℃, 50℃, etc. At each set ambient temperature, the battery was left to stand for a sufficient period of time to allow its internal temperature to fully balance with the ambient temperature. Subsequently, a constant current discharge was performed on the battery using charge-discharge testing equipment at a constant current exactly the same as the preset current threshold. The discharge process continued until the battery voltage reached the specified discharge termination condition, such as reaching the cutoff voltage or 100% depth of discharge of the rated capacity.

[0117] STEP2: During the discharge experiment, collect the battery's voltage, temperature, and corresponding real-time state of charge data.

[0118] Specifically, throughout the constant current discharge experiment, the system performs high-frequency, synchronous data acquisition. The acquired data includes: battery terminal voltage; battery surface or internal temperature; and state of charge (SOC) reference data. All acquired voltage and temperature data are timestamped and aligned with the corresponding real-time SOC values, forming multiple sets of one-to-one (V, T, SOC) data points.

[0119] STEP3: Based on the collected data, establish the correspondence between voltage, temperature and state of charge.

[0120] After obtaining complete discharge data at all temperature points, the data is further processed to establish the final mapping table, specifically including: All the original (V, T, SOC) data points are aggregated to form a three-dimensional dataset, such as... Figure 2 As shown.

[0121] Based on this dataset, an interpolation algorithm such as 3D linear interpolation or spline interpolation, or a surface fitting method, is used to generate a functional model or discretized lookup table that allows the State of Charge (SOC) to be obtained through a (V, T) query. This is the voltage-temperature-charge mapping table, which represents that under specific constant low-current discharge conditions, given the battery voltage and temperature at a certain moment, the corresponding state of charge can be uniquely determined.

[0122] The mapping table established using the above method is based directly on precise measurements of real batteries under simulated long-term low-current discharge conditions in vehicles, thus possessing high relevance and accuracy. This mapping table is pre-stored in the vehicle's battery management system memory, providing a standard reference for SOC calibration using real-time voltage and temperature under long-term low-current discharge conditions in vehicles.

[0123] Exemplary control terminal In one exemplary embodiment of this application, a vehicle is also provided.

[0124] Figure 3 This is a hardware architecture diagram of the vehicle provided in the embodiments of this application. See also... Figure 3 The vehicle includes a memory and a processor. The memory stores a computer program, and the processor executes the steps in the battery state estimation method according to various embodiments of the present application as described in the above embodiments.

[0125] The vehicle includes a processor, memory, network interface, and input devices connected via a system bus. The vehicle's processor provides computing and control capabilities. The vehicle's memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The vehicle's network interface is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it follows the steps in the battery state estimation method according to various embodiments of this application described in the above embodiments.

[0126] The processor may include the main processor, as well as baseband chips, modems, etc.

[0127] It is understood that the processor in the embodiments of this application can be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method embodiments can be completed by the integrated logic circuits in the processor's hardware or by instructions in software form. The processor can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly embodied in the execution of a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software modules can be located in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory; the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method.

[0128] It is understood that the memory in the embodiments of this application may be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. Specifically, non-volatile memory may be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory may be random access memory (RAM). It should be noted that the memory in the devices and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0129] Input devices may include devices that receive data and information input by the user, such as keyboards, mice, cameras, scanners, light pens, voice input devices, touch screens, pedometers, or gravity sensors.

[0130] Output devices may include devices that allow information to be output to the user, such as displays, printers, speakers, etc.

[0131] The communication interface may include any transceiver-like device for communicating with other devices or communication networks, such as Ethernet, Radio Access Network (RAN), Wireless Local Area Network (WLAN), etc.

[0132] The vehicle may also include a display component and a voice component. The display component may be an LCD screen or an e-ink screen. The input device of the vehicle may be a touch layer covering the display component, or it may be a button, trackball or touchpad set on the vehicle, or it may be an external keyboard, touchpad or mouse, etc.

[0133] Those skilled in the art will understand that Figure 3 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the vehicle to which the present application is applied. A specific vehicle may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0134] Exemplary computer program products and storage media In addition to the methods and devices described above, the battery state estimation method provided in the embodiments of this application can also be a computer program product, which includes computer program instructions that, when executed by a processor, cause the processor to perform the steps in the battery state estimation method according to various embodiments of this application as described in the "Exemplary Methods" section above.

[0135] The aforementioned computer program product can be implemented through hardware, software, or a combination thereof. In one optional embodiment, the computer program product is specifically embodied in a computer storage medium; in another optional embodiment, the computer program product is specifically embodied in a software product, such as a software development kit (SDK), etc.

[0136] The computer program product can be written in any combination of one or more programming languages ​​to perform the operations of the embodiments of this application. The programming languages ​​include object-oriented programming languages ​​such as Java and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0137] Furthermore, embodiments of this application also provide a computer-readable storage medium having a computer program stored thereon, the computer program being executed by a processor of the steps in the battery state estimation methods according to various embodiments of this application as described in the "Exemplary Methods" section above.

[0138] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0139] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0140] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the solutions provided in the embodiments of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for estimating the state of a battery, characterized in that, include: Obtain the duration during which the battery's discharge current is less than or equal to a preset current threshold; If the first preset condition is met based on the duration and the current minimum battery voltage, a first reference state of charge and a second reference state of charge are determined according to the battery temperature, the maximum battery voltage, and the minimum battery voltage. The target battery state of charge is then determined based on the first reference state of charge and the second reference state of charge.

2. The battery state estimation method according to claim 1, characterized in that, The method further includes: The battery health status is determined based on the cumulative throughput from the target battery state of charge to full charge and the target battery state of charge.

3. The battery state estimation method according to claim 1, characterized in that, The duration during which the battery discharge current is less than or equal to a preset current threshold specifically includes: The high-voltage state time is obtained when the battery is in a high-voltage power-on state and the discharge current is less than or equal to the preset current threshold. Obtain the sleep time when the battery is in a low-power sleep state; The sum of the high-pressure state time and the sleep time is taken as the duration.

4. The battery state estimation method according to claim 2 or 3, characterized in that, The first preset conditions include: The duration is greater than the calibrated resting time, wherein the calibrated resting time is used to represent the time required for complete elimination of battery polarization; The second reference state of charge obtained by querying the preset correspondence between the minimum battery voltage and the battery temperature is less than a preset state of charge threshold, wherein the preset correspondence is used to represent the correspondence between voltage, state of charge and temperature.

5. The battery state estimation method according to claim 1, characterized in that, Determining the target battery state of charge based on the first reference state of charge and the second reference state of charge includes: If the first reference state of charge is less than a preset state of charge threshold, the target battery state of charge is determined based on the first reference state of charge.

6. The battery state estimation method according to claim 1, characterized in that, Determining the target battery state of charge based on the first reference state of charge and the second reference state of charge includes: When the first reference state of charge is greater than or equal to a preset state of charge threshold and the second reference state of charge is less than the preset state of charge threshold, a first state of charge difference between the actual maximum state of charge and the actual minimum state of charge is obtained. The target battery state of charge is determined based on the sum of the differences between the second reference state of charge and the first state of charge.

7. The battery state estimation method according to claim 1, characterized in that, Determining the target battery state of charge based on the first reference state of charge and the second reference state of charge includes: If the first reference state of charge is greater than or equal to a preset state of charge threshold, and the second reference state of charge is greater than or equal to a preset state of charge threshold, no calibration based on the first reference state of charge and the second reference state of charge is performed, and the target state of charge is not updated, and the current value of the target state of charge is kept as the value of the previous time step.

8. The battery state estimation method according to claim 1, characterized in that, The method further includes: When the discharge current of the battery is greater than the preset current threshold, the battery health status is determined based on the cumulative throughput from the target battery state of charge to the battery full charge and the target battery state of charge.

9. The battery state estimation method according to claim 1, characterized in that, The method further includes: If the duration is greater than the first time threshold and less than the calibrated resting time, the preset state of charge is taken as the target battery state of charge, wherein the preset state of charge is a value that exceeds the normal range of 0% to 100%, and the historical cumulative throughput is cleared to zero.

10. The battery state estimation method according to claim 2, characterized in that, The method further includes: If the second state of charge difference between the fully charged state of charge and the target battery state of charge is greater than a preset state of charge threshold, the battery health status is determined based on the ratio of the cumulative throughput to the second state of charge difference.

11. A vehicle, characterized in that, The vehicle includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the battery state estimation method as described in any one of claims 1 to 10.

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