Methods and related equipment for determining the state of charge of batteries

Abstract

This application discloses a method and related equipment for determining the state of charge (SOC) of a battery, relating to the field of new energy vehicle technology. The method includes: acquiring the SOC value at the start of a target vehicle entering a preset low-power operating condition, as the initial SOC value of the target vehicle's battery pack; acquiring the cumulative power consumption collected by the target vehicle's DC-DC converter under the preset low-power operating condition; determining the first capacity consumption of the battery pack based on the cumulative power consumption; and determining the current SOC value of the battery pack under the preset low-power operating condition based on the first capacity consumption and the initial SOC value. This application, by using the initial SOC as a starting point and employing an accurate measurement of stable power consumption on the low-voltage side via a DC-DC converter to replace the small current measurement on the high-voltage side, enables more reliable SOC estimation under low-power operating conditions, with less error accumulation and consistency with actual energy consumption.

Description

Technical Field

[0001] This application relates to the field of new energy vehicle technology, and more specifically, to a method and related equipment for determining the state of charge of a battery. Background Technology

[0002] With the continuous development of new energy vehicle technology, the battery management system (BMS), as a core component ensuring vehicle performance and safety, is becoming increasingly important in its ability to accurately estimate the battery's state of charge (SOC). Especially when the vehicle is parked for extended periods or in low-power operation mode, the battery continues to power low-voltage electrical equipment, placing higher demands on the long-term stability and accuracy of SOC estimation. Therefore, optimizing and improving methods for determining the battery's state of charge under low-power conditions has become a key focus of the industry.

[0003] In related technologies, the estimation of battery state of charge (SOC) typically relies on the acquisition and integration of battery pack current. However, under low-power operating conditions, the battery output current is usually small and easily affected by factors such as sensor accuracy limitations, signal noise, and zero-point drift, leading to unstable or even distorted current acquisition results. In this situation, SOC estimation methods based on current integration are prone to accumulating errors, which amplify over time and are difficult to correct in a timely manner, thus affecting the accuracy and reliability of SOC estimation. In other words, existing technologies suffer from insufficient accuracy in estimating the battery SOC of new energy vehicles under low-power conditions, with errors easily accumulating and difficult to correct. Summary of the Invention

[0004] In the summary section of this application, the relevant technical solutions are described in general terms, and a series of simplified concepts are introduced. These concepts will be further elaborated in the detailed embodiments section. This summary section should not be construed as limiting the key or essential technical features of the claimed solutions, nor is it intended to limit the scope of protection of the claimed solutions.

[0005] The battery state of charge determination method and related equipment provided in this application can replace the small current measurement on the high-voltage side by using the accurate measurement of stable power consumption on the low-voltage side with a DC-DC converter starting from the initial state of charge. This enables more reliable SOC estimation under low power consumption conditions, with less error accumulation and consistent with actual energy consumption.

[0006] In a first aspect, this application provides a method for determining the state of charge (SOC) of a battery, applied to a target vehicle, comprising: acquiring the SOC value at the start time of the target vehicle entering a preset low-power operating condition, as the initial SOC value of the battery pack of the target vehicle; acquiring the cumulative power consumption of the target vehicle under the preset low-power operating condition, collected by the DC-DC converter of the target vehicle, wherein the DC-DC converter is connected to the battery pack and is used to provide power to the low-voltage electrical equipment of the target vehicle; determining a first capacity consumption of the battery pack based on the cumulative power consumption; and determining the current SOC value of the battery pack under the preset low-power operating condition based on the first capacity consumption and the initial SOC value.

[0007] In some embodiments, the battery state of charge determination method further includes: acquiring the operating status information of the target vehicle and the output current of the battery pack; and determining that the target vehicle has entered the preset low-power operating condition when the operating status information indicates that the target vehicle is in a parked state and the output current is less than a preset current threshold.

[0008] In some implementations, obtaining the cumulative power consumption of the target vehicle under the preset low-power operating condition, collected by the DC-DC converter of the target vehicle, includes: obtaining the first current sampling value and the first voltage sampling value of the DC-DC converter for each sampling within a statistical period, wherein the statistical period is the period during which the target vehicle is in the preset low-power operating condition and the DC-DC converter is in operation; multiplying the first current sampling value and the first voltage sampling value corresponding to each sampling within the statistical period and performing cumulative processing to obtain the cumulative power consumption.

[0009] In some implementations, determining the first capacity consumption of the battery pack based on the cumulative power consumption includes: acquiring the second voltage sample value of the DC-DC converter for each sampling within the statistical period, and the power consumption within the sampling interval of each sampling; for each sampling within the statistical period, determining the unit capacity consumption within the sampling interval of that sampling based on the ratio of the power consumption within the sampling interval of that sampling to the second voltage sample value of that sampling; and accumulating the unit capacity consumption corresponding to each sampling within the statistical period to obtain the first capacity consumption.

[0010] In some implementations, determining the current state of charge (SOC) value of the battery pack under the preset low-power operating condition based on the first capacity consumption and the initial SOC value includes: determining a first SOC change based on the ratio of the first capacity consumption to the rated capacity of the battery pack; performing a difference calculation on the initial SOC value and the first SOC change to obtain an intermediate SOC value; and determining the current SOC value based on the intermediate SOC value.

[0011] In some embodiments, determining the current state of charge (SOC) value based on an intermediate SOC value includes: when the DC-DC converter is in operation, determining the intermediate SOC value as the current SOC value; when the DC-DC converter is in sleep mode, compensating the high-voltage circuit current of the battery pack based on a power consumption acquisition error rate, and correcting the intermediate SOC value based on the compensated current integral value to obtain the current SOC value, wherein the power consumption acquisition error rate is used to characterize the zero-drift characteristic of the high-voltage circuit current sensor under the preset low-power operating condition.

[0012] In some embodiments, when the DC-DC converter is in a dormant state, compensating the high-voltage circuit current of the battery pack based on the power consumption acquisition error rate, and correcting the intermediate state of charge value based on the compensated current integral value to obtain the current state of charge value, includes: acquiring a second current sampling value each time the high-voltage circuit current sensor of the target vehicle is sampled during the period when the DC-DC converter is in the dormant state, wherein the high-voltage circuit current sensor is disposed in the high-voltage circuit of the battery pack for collecting current data of the high-voltage circuit; compensating the second current sampling value based on the power consumption acquisition error rate to obtain a third current sampling value; performing time integration processing on the third current sampling value during the period when the DC-DC converter is in the dormant state to obtain a second state of charge change; and performing a difference calculation between the intermediate state of charge value of the DC-DC converter at the start of the dormant state and the second state of charge change to obtain the current state of charge value.

[0013] In some implementations, before compensating the second current sample value based on the power consumption acquisition error rate to obtain the third current sample value, the battery state of charge determination method further includes: acquiring a fourth current sample value and a third voltage sample value from each sampling of the high-voltage circuit current sensor within a statistical period; determining a second capacity consumption of the battery pack based on the fourth current sample value and the third voltage sample value; and determining the power consumption acquisition error rate based on the first capacity consumption and the second capacity consumption.

[0014] In some implementations, determining the power consumption collection error rate based on the first capacity consumption and the second capacity consumption includes: performing a difference calculation on the second capacity consumption and the first capacity consumption to obtain a capacity consumption deviation; and determining the ratio of the capacity consumption deviation to the duration of the statistical period as the power consumption collection error rate.

[0015] In some embodiments, the step of compensating the second current sample value based on the power consumption acquisition error rate to obtain the third current sample value includes: performing temperature correction on the power consumption acquisition error rate based on the ambient temperature information of the target vehicle to obtain a target acquisition error rate; and compensating the second current sample value based on the target acquisition error rate to obtain the third current sample value.

[0016] In some embodiments, the battery pack is a lithium iron phosphate battery pack.

[0017] Secondly, this application also provides a battery state of charge (SOC) determination device, applied to a target vehicle, comprising: a SOC acquisition unit, configured to acquire the SOC value at the start time of the target vehicle entering a preset low-power operating condition, as the initial SOC value of the battery pack of the target vehicle; a cumulative power consumption acquisition unit, configured to acquire the cumulative power consumption of the target vehicle under the preset low-power operating condition, collected by the DC-DC converter of the target vehicle, wherein the DC-DC converter is connected to the battery pack and is used to provide power to the low-voltage electrical equipment of the target vehicle; a capacity consumption determination unit, configured to determine a first capacity consumption of the battery pack based on the cumulative power consumption; and a SOC determination unit, configured to determine the current SOC value of the battery pack under the preset low-power operating condition based on the first capacity consumption and the initial SOC value.

[0018] Thirdly, this application also provides a vehicle, including: a memory and a processor, the processor being configured to execute a computer program stored in the memory to implement the steps of the battery state of charge determination method described in the first aspect.

[0019] Fourthly, this application also provides a computer-readable storage medium storing computer-executable instructions or a computer program, wherein when the computer-executable instructions or the computer program are executed by a processor, the steps of the battery state-of-charge determination method described in the first aspect are implemented.

[0020] Fifthly, this application also provides a computer program product, including a computer program or computer-executable instructions, which, when executed by a processor, implement the steps of the battery state-of-charge determination method provided in the embodiments of this application.

[0021] In summary, this application uses the initial state of charge (SOC) upon entering low-power operation as a benchmark, and gradually corrects the remaining battery capacity based on subsequent accumulated power consumption. Essentially, it transforms changes in battery state into a "consumption process starting from a known starting point." This avoids directly relying on battery-side current measurements to continuously estimate capacity changes under low-current conditions, making the SOC calculation path clearer and more stable, thereby improving the overall reliability of the estimation. Furthermore, by shifting the acquisition of power consumption from high-voltage side current acquisition to the power consumption statistics of the DC-DC converter on the low-voltage load, and because low-voltage side power consumption is continuous and relatively stable under low-power conditions, its power consumption is easier to record accurately. Therefore, it effectively reduces measurement errors caused by excessively small or fluctuating current signals, preventing errors from accumulating over long periods, thus improving the SOC results. Accuracy: As an energy channel connecting the battery pack and low-voltage electrical equipment, the DC-DC converter's cumulative power consumption accurately reflects the vehicle's actual energy consumption under certain operating conditions. Based on this, converting the low-voltage side's energy consumption into the battery pack's capacity consumption ensures that the SOC update process remains consistent with actual energy usage, giving the calculation results good physical rationality and enhancing the reliability of the estimation results. Under low-power conditions, the vehicle's energy flow path is relatively simple and stable, mainly manifested in the battery supplying energy to the low-voltage system through the DC-DC converter. Utilizing this characteristic to establish an SOC update mechanism makes the calculation process less susceptible to interference from complex operating condition changes. In long-term parking or similar low-power scenarios, it can achieve more stable and continuous SOC estimation results, reducing fluctuations caused by signal instability. In summary, the battery state of charge determination method provided in this application, by starting with the initial state of charge and using the accurate measurement of stable power consumption on the low-voltage side via the DC-DC converter to replace the small current measurement on the high-voltage side, can achieve more reliable SOC estimation under low-power conditions, with less error accumulation and consistency with actual energy consumption. Attached Figure Description

[0022] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit this specification. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 A flowchart illustrating a method for determining the state of charge of a battery, as provided in an embodiment of this application; Figure 2 This is a schematic diagram of the composition structure of a battery state of charge determination device provided in an embodiment of this application; Figure 3 This is a schematic diagram of the composition structure of a vehicle provided in an embodiment of this application. Detailed Implementation

[0023] The terms used in the specification, claims, and drawings of this application, such as "first," "second," "third," "fourth," etc. (if any), are used to distinguish similar objects and not to describe a specific order or sequence. Therefore, it is to be understood that these terms can be used interchangeably where appropriate, allowing the described embodiments to be used in different orders, unless specifically required by the illustrations or description. Furthermore, the terms "is" and "has," and any variations thereof, are intended to cover, non-exclusively, all possible constituent elements. For example, a process, method, system, product, or apparatus comprising several steps or units is not necessarily limited to the steps or units explicitly listed, but may also include other steps or units not explicitly listed, or steps or units inherent to the process, method, product, or apparatus.

[0024] In this application, a "module" or "unit" refers to a computer program or part of a computer program that has a specific function and works in conjunction with other related parts to achieve a predetermined goal. These modules or units can be implemented by software, hardware (e.g., processing circuitry or memory), or a combination of both. One or more processors or memories can implement one or more modules or units. Furthermore, each module or unit can also be part of a larger module or unit.

[0025] The technical solutions of this application will be described in detail below with reference to the accompanying drawings of the embodiments. It should be noted that the described embodiments are only a part of this application, and not all embodiments. In the following description, the "some embodiments" mentioned are only a subset of all possible embodiments, which may be the same or different subsets, and different embodiments can be combined with each other without conflict.

[0026] Figure 1 This is a schematic flowchart illustrating a method for determining the state of charge of a battery according to an embodiment of this application. For example, see [link to example]. Figure 1 The battery state of charge determination method provided in this application embodiment is applied to a target vehicle, which is a new energy vehicle equipped with a power battery pack and a low-voltage direct current converter (DC), covering pure electric new energy vehicles and plug-in hybrid new energy vehicles. The target vehicle is equipped with a battery management system (BMS), which can collect real-time vehicle operating status, battery current and voltage data to provide data support for battery state of charge calculation. The battery state of charge determination method provided in this application embodiment embodiment may include the following steps 101 to 104: Step 101: Obtain the state of charge value at the start of the target vehicle entering the preset low power consumption condition, and use it as the initial state of charge value of the target vehicle's battery pack.

[0027] In some examples, the preset low-power operating condition is a pre-calibrated, low-power operating condition of the vehicle when stationary, distinct from high-power dynamic operating conditions such as vehicle driving and charging. It is mainly used to define the operating scenario where the vehicle is parked and stationary, with no power output and low battery current consumption. The battery management system can collect the vehicle's operating status information and battery pack output current data in real time, and identify the operating condition by combining dual judgment conditions. For example, the parking and stationary scenario in which the vehicle is turned off and locked, the sentry security monitoring function is activated, and the battery pack continuously discharges at a low current with an output current of less than 3 amps, belongs to the preset low-power operating condition in the embodiments of this application.

[0028] The initial state of charge (SOC) value refers to the state of charge remaining in the battery pack, which represents the proportion of the battery pack's current available capacity to its rated total capacity. Specifically, the initial SOC value is the real-time remaining capacity value of the battery pack at the critical moment when the target vehicle just enters the preset low-power operating condition. It serves as the benchmark parameter for subsequent iterative calculations of the battery's SOC under low-power operating conditions. The initial SOC value can be obtained by the battery management system by capturing the time node of the operating condition switch and retrieving the battery SOC data that has been calibrated at that instant. For example, when the vehicle is parked and the sentry mode is activated, and the low-power operating condition judgment conditions are met, the battery management system collects data showing that the remaining battery capacity is 82% of the rated capacity. This value is the initial SOC value for this operating condition.

[0029] At the instant when the vehicle enters the preset low-power operating condition, the real-time remaining power data of the current battery pack is captured and locked, and the instantaneous power data is defined as the initial state of charge value of this low-power power calculation cycle. For example, at the instant when the vehicle is locked and parked and the low-power operating condition is met, the battery management system collects the remaining battery power as 75%, and this instantaneous power value is the initial state of charge value used for the calculation of this operating condition.

[0030] For example, the battery management system monitors the target vehicle's driving status and the battery's high-voltage circuit output current around the clock in real time, continuously comparing the vehicle's operating parameters with preset low-power operating condition judgment thresholds. Once the vehicle's status meets the judgment criteria of being parked and idling with low current consumption, the system immediately locks the start time of the operating condition switch; at the same time, it freezes the battery state of charge calculation results at that instant and accurately retains the basic calculation parameters; in this way, it completes the low-power operating condition identification and initial power parameter acquisition, providing an accurate and stable calculation benchmark for subsequent high-precision state of charge estimation.

[0031] By implementing step 101, the initial state of charge of the battery when the vehicle enters the low-power operating condition is used as the starting point for calculation. This provides a clear and unified benchmark reference for subsequent changes in battery charge, which can avoid the continued accumulation of historical errors in the low-power stage and enable the SOC update to be based on a relatively accurate initial state, thereby improving the overall reliability of subsequent estimation results.

[0032] Step 102: Obtain the cumulative power consumption of the target vehicle under preset low power consumption conditions, collected by the DC-DC converter of the target vehicle.

[0033] The DC-DC converter is connected to the battery pack and is used to provide power to the low-voltage electrical equipment of the target vehicle.

[0034] In some examples, a DC-DC converter, also known as a low-voltage DC-DC converter, is an energy conversion device installed between the high-voltage and low-voltage power supply systems of a target vehicle. The input of this device is electrically connected to the vehicle's power battery pack, and the output is connected to the vehicle's low-voltage power supply line. It is used to convert the high-voltage DC power output from the battery pack into low-voltage DC power suitable for the operation of the vehicle's low-voltage equipment. For example, a low-power on-board DC-DC converter installed in the target vehicle can convert the 300 to 400 volts of high-voltage power from the power battery pack into 12 volts of low-voltage power to continuously power the vehicle's low-voltage auxiliary equipment.

[0035] Low-voltage electrical equipment refers to various on-board electrical devices that are adapted to the low-voltage output standard of DC-DC converters and connected to the vehicle's low-voltage power supply network. These devices are also the core power-consuming devices under the vehicle's preset low-power operating conditions. These devices only rely on the low-voltage electrical energy converted by the DC-DC converter to work and do not directly consume the high-voltage electrical energy of the battery pack. For example, vehicle parking sentry monitoring cameras, vehicle anti-theft control modules, vehicle body low-voltage signal acquisition units, and on-board sleep monitoring controllers, which are electrical devices that are always stationary in the vehicle, all belong to low-voltage electrical equipment.

[0036] Cumulative power consumption is the total electrical energy consumed by all low-voltage electrical equipment during a complete statistical period when the target vehicle is stably operating under a preset low-power condition and the DC-DC converter is running normally. Cumulative power consumption can be calculated using the high-precision power metering program built into the DC-DC converter. The device collects instantaneous electrical parameters at a fixed sampling frequency, calculates the instantaneous power consumption for each instance, and then continuously accumulates the data to generate the total power consumption data for the statistical period. For example, if the target vehicle is locked and parked with the sentry monitoring function activated, the DC-DC converter continuously collects and calculates data during a 30-minute low-power operating period. The total power consumption value of all low-voltage equipment in the vehicle obtained by summarizing the data is the cumulative power consumption for that period.

[0037] For example, when the target vehicle determines that it has entered a preset low-power operating condition, the vehicle's high-voltage system enters a low-power sleep state, with only the low-voltage power supply link remaining in normal operation; the DC-DC converter remains in an active working state, collecting voltage and current parameters on the output side at a preset high-frequency sampling rate; it independently completes the instantaneous power consumption calculation for each sampling cycle, and stores all sampling data in real time, continuously accumulating and integrating to generate accurate cumulative power consumption; the entire data acquisition and processing process is independent of the vehicle's high-voltage circuit, which can completely avoid the defects of zero drift and insufficient accuracy in low-current acquisition by high-voltage current sensors.

[0038] By implementing step 102, the cumulative power consumption of the low-voltage side is collected using a DC-DC converter, shifting the power acquisition path from the small current measurement on the high-voltage side to the more stable low-voltage load energy consumption statistics. Since the low-voltage power consumption is continuous and stable under low power consumption conditions, this can more accurately reflect the actual energy consumption, thereby reducing the measurement error caused by weak or fluctuating current signals.

[0039] Step 103: Determine the first capacity consumption of the battery pack based on the cumulative power consumption.

[0040] In some examples, the first capacity consumption is the total high-voltage battery capacity equivalent to that consumed by the power battery pack when the target vehicle is in a preset low-power operating condition, which supplies power to the low-voltage electrical equipment of the vehicle. This parameter is used to quantify the scale of power consumption of the battery pack under low-power operating conditions and is a core basic parameter for updating the remaining battery power status. For example, when the target vehicle is parked and the low-power sentinel monitoring function is activated, the low-voltage equipment of the vehicle continues to consume power. The battery management system calculates the corresponding ampere-hour capacity consumed by the power battery pack based on the total power consumption statistics on the low-voltage side. The calculated battery capacity value is the first capacity consumption.

[0041] For example, the target vehicle continuously maintains a preset low-power stable operating state; the battery management system fully receives the cumulative power consumption data of the operating cycle from the DC voltage converter, and combines it with the real-time operating voltage of the battery pack to complete the standardized conversion of energy and capacity, accurately calculate the overall power consumption capacity of the battery pack under this operating condition, thereby obtaining an accurate and reliable first capacity consumption, providing accurate data support for the subsequent iterative calculation of the remaining state of charge of the battery.

[0042] By implementing step 103, the cumulative power consumption collected by the DC-DC converter is further converted into the capacity consumption of the battery pack, realizing an effective mapping from "energy consumption" to "power change". This enables the battery consumption to directly correspond to the actual power consumption, ensuring that the data used in the SOC calculation process has clear physical meaning, thereby enhancing the rationality of the estimation process.

[0043] Step 104: Based on the first capacity consumption and the initial state of charge value, determine the current state of charge value of the battery pack under the preset low power consumption condition.

[0044] In some examples, the current state of charge (SOC) value is the real-time remaining battery charge value determined after precise charge conversion and error correction during continuous operation of the target vehicle's battery pack under a preset low-power condition. The current SOC value can be generated by the battery management system by calling the initial SOC value and the first capacity consumption corresponding to the preset low-power condition and calculating it using a standardized charge calculation algorithm. For example, when the target vehicle enters the Sentinel low-power condition, the initial remaining charge is 90%. After a fixed period of low-voltage equipment power consumption, the corresponding capacity consumption of the battery pack is calculated. The battery management system updates the calculation to obtain a remaining battery charge of 87%. This calculated remaining charge value is the current SOC value.

[0045] For example, after the target vehicle completes a single preset low-power operation cycle of power statistics, the battery management system summarizes all valid calculation parameters, calibrates the power benchmark based on the initial state of charge value, and completes power correction and calculation by combining accurate battery capacity consumption data, and finally outputs the current state of charge value that matches the actual power consumption of the power battery.

[0046] By implementing step 104, the capacity consumption is combined with the initial state of charge to update the current state of charge of the battery pack, realizing dynamic correction based on actual energy consumption. This can continuously and stably reflect the changes in the remaining battery capacity under low power consumption conditions, avoiding the problem of gradual error accumulation in traditional methods, thereby improving the accuracy and continuity of SOC estimation results.

[0047] In summary, this application's embodiment uses the initial state of charge (SOC) upon entering a low-power operating condition as a benchmark, and gradually corrects the remaining battery capacity through subsequent accumulated power consumption. Essentially, it transforms the change in battery state into a "consumption process starting from a known starting point." This avoids directly relying on battery-side current measurements to continuously estimate power changes under low-current conditions, making the SOC calculation path clearer and more stable, thereby improving the overall estimation reliability. Furthermore, it shifts the acquisition of power consumption from high-voltage side current acquisition to the power consumption statistics of the DC-DC converter on the low-voltage load. Since low-voltage side power consumption is continuous and relatively stable under low-power conditions, its power consumption is easier to record accurately. Therefore, it can effectively reduce measurement errors caused by excessively small or fluctuating current signals, preventing errors from accumulating over long periods, thus improving the SOC result. The accuracy of the SOC (State of Charge) estimation is improved. As the energy channel connecting the battery pack and low-voltage electrical equipment, the DC-DC converter's cumulative power consumption accurately reflects the vehicle's actual energy consumption under certain operating conditions. Based on this, converting the low-voltage side's energy consumption into the battery pack's capacity consumption ensures that the SOC update process remains consistent with actual energy usage, giving the calculation results good physical rationality and enhancing the reliability of the estimation results. Under low-power conditions, the vehicle's energy flow path is relatively simple and stable, mainly manifested in the battery supplying energy to the low-voltage system through the DC-DC converter. Utilizing this characteristic to establish an SOC update mechanism makes the calculation process less susceptible to interference from complex operating condition changes. In long-term parking or similar low-power scenarios, it can achieve more stable and continuous SOC estimation results, reducing fluctuations caused by signal instability. In summary, the battery state of charge determination method provided in this application, by starting with the initial state of charge and using the accurate measurement of stable power consumption on the low-voltage side via the DC-DC converter to replace the small current measurement on the high-voltage side, can achieve more reliable SOC estimation under low-power conditions, with less error accumulation and consistency with actual energy consumption.

[0048] In some embodiments, the aforementioned battery state of charge determination method may further include: acquiring the operating state information of the target vehicle and the output current of the battery pack; and determining that the target vehicle has entered a preset low-power operating condition when the operating state information indicates that the target vehicle is in a parked state and the output current is less than a preset current threshold.

[0049] In some examples, the target vehicle's operating status information is a set of vehicle parameters that characterize the overall operating mode and motion state of the new energy vehicle. This is used to distinguish between the vehicle's stationary parking condition and high-power operating conditions such as driving, charging, and dynamic load. The operating status information can be collected and summarized in real time by the vehicle control unit (VCU) and sent to the battery management system in real time via the controller area network (CAN) bus. For example, parameters such as vehicle gear position signal, vehicle speed signal, handbrake lock signal, and door lock signal together constitute the target vehicle's operating status information, which can accurately reflect whether the vehicle is in a stationary parking state.

[0050] The output current of the battery pack is the real-time operating current of the high-voltage output circuit of the power battery pack. It can directly reflect the power of the battery pack's output electrical energy and is a key electrical parameter that distinguishes between high-power and low-power operating conditions of the vehicle. It can be detected in real time by current acquisition devices arranged in the high-voltage circuit of the battery pack. For example, when the vehicle is driving normally, the battery pack outputs a large current to drive the vehicle's running gear. When the vehicle is locked and stationary, the battery pack only outputs a small current to maintain the standby operation of the vehicle's low-voltage equipment. The real-time current data of this high-voltage circuit is the output current of the battery pack.

[0051] This application's embodiments abandon the single-parameter judgment method and combine the vehicle's mechanical operating state and the battery's electrical output state for joint judgment. Low-power condition recognition can only be triggered when the vehicle is completely stationary at the mechanical level and the battery is in a low-current, low-power discharge state at the electrical level. The preset current threshold is a fixed parameter calibrated before the vehicle leaves the factory, which is specifically used to distinguish between high-current operating conditions and low-current stationary conditions of the high-voltage circuit. For example, when the vehicle speed is zero, the parking lock signal is valid, and the high-voltage output current of the battery pack is continuously less than 3 amps, it can be determined that the target vehicle has entered the preset low-power condition.

[0052] For example, the vehicle controller continuously monitors all vehicle operating parameters and continuously pushes vehicle operating status information to the battery management system. The battery management system synchronously collects the output current of the high-voltage circuit of the battery pack, compares it with the built-in preset current threshold in real time, and continuously verifies the dual judgment conditions of the vehicle parking status and the battery low current output, accurately capturing the critical moment of the switching of operating conditions. Once the judgment condition takes effect, the instantaneous state of charge data is immediately locked, providing a stable and accurate initial calculation benchmark for the accurate estimation of battery power under subsequent low power consumption conditions.

[0053] By implementing the above embodiments, the low-power operating conditions are determined by combining the vehicle's operating status and the battery's output current, and the initial state of charge value is locked at the moment of operating condition switching. This can ensure the accuracy and consistency of the SOC calculation starting point, help avoid erroneous triggering of calculation logic under atypical operating conditions, reduce the introduction of errors from the source, and improve the reliability of subsequent SOC estimation.

[0054] In some embodiments, the aforementioned acquisition of the cumulative power consumption collected by the DC-DC converter of the target vehicle under a preset low-power operating condition may include: acquiring the first current sampling value and the first voltage sampling value of the DC-DC converter for each sampling within a statistical period, wherein the statistical period is the period during which the target vehicle is in a preset low-power operating condition and the DC-DC converter is in operation; multiplying the first current sampling value and the first voltage sampling value corresponding to each sampling within the statistical period and performing cumulative processing to obtain the cumulative power consumption.

[0055] The corresponding cumulative power consumption calculation formula is as follows:

[0056] in, This represents the cumulative power consumption on the low-voltage side during the statistical period. The first voltage sample value of the i-th sampling is... The first current sample value of the i-th sampling is... To fix the sampling interval duration, This represents the total number of samples taken within the statistical period.

[0057] In some examples, the statistical period is a valid timing interval specifically used for low-voltage side power consumption statistics. It is a continuous period of time during which the target vehicle is stably in a preset low-power condition and the DC voltage converter on the low-voltage side is in normal working condition. This period is an effective statistical interval for power consumption calculation, which can avoid invalid data statistics problems caused by abnormal vehicle conditions or converter hibernation. For example, a continuous 25-minute period during which the target vehicle is parked and enters the Sentinel low-power condition, and the DC voltage converter is continuously powered on and supplies power to the vehicle's low-voltage equipment, is a complete statistical period.

[0058] The first current sample value is the real-time output current parameter collected by the DC-DC converter output side in each independent sampling period. It directly represents the instantaneous operating current of the low-voltage electrical equipment. The DC-DC converter can be equipped with a built-in high-precision current sampling unit to periodically collect the low-voltage output circuit current in real time according to a preset fixed sampling frequency. For example, the 0.2 amp output current generated by the low-voltage side vehicle-mounted monitoring equipment at a single sampling node within the statistical period is the first current sample value corresponding to that sampling moment. The first voltage sample value is the real-time output voltage parameter synchronously collected by the DC-DC converter output side in each independent sampling period. It represents the instantaneous operating voltage of the low-voltage power supply circuit. The DC-DC converter can be equipped with a built-in voltage sampling module to synchronously complete periodic voltage data acquisition with current sampling, ensuring the temporal consistency of the current and voltage parameters at a single sampling moment. For example, the stable 12-volt low-voltage supply voltage output by the DC-DC converter during each sampling process within the statistical period is the first voltage sample value corresponding to each sampling node.

[0059] Multiplying the first current sample value and the first voltage sample value within a single sampling period yields the instantaneous power consumption of the low-voltage equipment at the corresponding moment. Combining this with the sampling period, the instantaneous power consumption of a single sampling interval can be obtained. By summing up the instantaneous power consumption corresponding to all sampling nodes within the statistical period, the total power consumption data of the low-voltage equipment within the entire effective operating cycle can be obtained. For example, within a 25-minute statistical period, the equipment completes hundreds of periodic samplings. The current and voltage data corresponding to each sampling are multiplied, and all the single calculation results are summed up to finally obtain the total electrical energy consumed by the low-voltage equipment within that operating cycle.

[0060] For example, after entering the working state, the DC voltage converter continuously collects the electrical parameters of the low-voltage circuit at a fixed frequency, matching the vehicle's preset low-power operating condition throughout the process. It only collects power consumption data when the operating condition is valid and the equipment is working normally. By collecting data one by one, calculating data one by one, and accumulating data periodically, it accurately counts the total power consumption on the low-voltage side. It relies entirely on the high-precision sampling device on the low-voltage side to complete the data collection and calculation, effectively avoiding the defect of insufficient sampling accuracy of the low current in the high-voltage circuit. This provides accurate and reliable raw power consumption data for subsequent battery capacity consumption conversion and state of charge calculation.

[0061] By implementing the above embodiments, the current and voltage of the DC converter are sampled successively during the statistical period and the cumulative power consumption is calculated. This enables a more detailed characterization of the actual energy consumption on the low-voltage side. Continuous sampling improves data resolution, making the power consumption statistics closer to the actual power consumption situation. This provides a more accurate data basis for subsequent capacity consumption calculations and reduces measurement uncertainty.

[0062] In some embodiments, step 103 may include: acquiring the second voltage sample value of the DC-DC converter for each sampling within a statistical period, and the power consumption within the sampling interval of each sampling; for each sampling within the statistical period, determining the unit capacity consumption within the sampling interval of that sampling based on the ratio of the power consumption within the sampling interval of that sampling to the second voltage sample value of that sampling; and accumulating the unit capacity consumption corresponding to each sampling within the statistical period to obtain the first capacity consumption.

[0063] The corresponding formulas for calculating unit capacity consumption and first capacity consumption are as follows:

[0064]

[0065] in, This represents the unit capacity consumption within the i-th sampling interval. The low-voltage power consumption during the i-th sampling interval. The second voltage sample value is the i-th sample. This represents the first capacity consumption.

[0066] In some examples, the second voltage sample value is the real-time operating voltage of the high-voltage side of the power battery pack collected at each sampling moment within the statistical period. It is used to realize the equivalent conversion from low-voltage power consumption to high-voltage battery capacity consumption. This voltage parameter is different from the low-voltage side sampling voltage and can reflect the current output voltage state of the battery pack. The second voltage sample value can be collected by the battery management system at the synchronization moment when the DC-DC converter completes a single data sampling, to ensure that the voltage sampling and low-voltage power consumption sampling timing are completely aligned. For example, in a single sampling node of the target vehicle's low-power parking condition, the battery management system collects the real-time high-voltage operating voltage of the power battery pack as 320 volts. This voltage value is the second voltage sample value corresponding to this sampling.

[0067] The power consumption within each sampling interval is the instantaneous power consumed by all low-voltage electrical equipment of the target vehicle powered by the DC-DC converter during a single fixed sampling period. This parameter is the raw energy consumption data accurately collected from the low-voltage side and is the basic parameter for calculating the high-voltage battery capacity consumption. The DC-DC converter can retrieve the first current sampling value and the first voltage sampling value corresponding to this sampling, multiply the two sets of parameters, and obtain the power consumption value corresponding to a single sampling interval. For example, within a single sampling period, the DC-DC converter combines the collected low-voltage current and low-voltage to complete the calculation and obtain that the low-voltage equipment consumes 0.05 watt-hours of power in this interval. This value is the power consumption within a single sampling interval.

[0068] The unit capacity consumption within the sampling interval of this sampling is the equivalent high-voltage battery capacity loss caused by the power consumption of the corresponding low-voltage equipment in a single sampling interval. This parameter is calculated based on the principle of energy conservation and can accurately convert low-voltage side power loss into high-voltage battery capacity loss. The battery management system can retrieve the power consumption of a single sampling interval and the synchronously collected second voltage sampling value. By calculating the ratio of power consumption to high-voltage voltage, the battery capacity consumption value corresponding to a single sampling can be obtained. For example, if the low-voltage power consumption in a single sampling interval is 0.05 Wh and the corresponding high-voltage sampling voltage is 320 V, the power parameter of 0.05 Wh is divided by the high-voltage voltage parameter of 320 V to calculate the corresponding small capacity loss value of the high-voltage battery, which is the unit capacity consumption value corresponding to this sampling.

[0069] A single sample can only reflect the instantaneous battery capacity consumption and cannot characterize the total loss of a complete operating cycle. The unit capacity consumption of all sampling nodes within the statistical period can be traversed, and all discrete single capacity consumption data can be accumulated and summarized to finally obtain the total capacity loss of the battery pack in the entire low-power statistical period. For example, a low-power statistical period lasting ten minutes contains thousands of samples. The unit capacity consumption calculated from each sample is accumulated and summarized one by one, and the final total battery capacity consumption value is the first capacity consumption corresponding to this operating condition.

[0070] For example, the DC-DC converter continuously and periodically collects low-voltage side electrical parameters within a preset statistical period, generating low-voltage power consumption for each sampling interval; the battery management system synchronously matches and collects high-voltage parameters of the power battery pack, and performs high-voltage battery unit capacity consumption conversion for each sampling node; the battery management system continuously stores the calculation data from each operation, and completes the accumulation and summarization of all data after the statistical period ends. By relying on high-precision low-voltage side sampling data to complete high-voltage battery capacity calculation, the problem of high-voltage low-current sampling drift is effectively avoided, significantly improving the accuracy of battery capacity consumption statistics under low-power conditions.

[0071] By implementing the above embodiments, the power consumption in each sampling interval is matched and converted with the corresponding voltage, and the capacity consumption is gradually accumulated to obtain the capacity consumption. This enables the segmented and accurate conversion of energy to capacity, which can better adapt to the impact of voltage fluctuations, making the capacity consumption calculation results more refined and stable, thereby further improving the accuracy of SOC estimation.

[0072] In some embodiments, step 104 may include: determining a first state of charge change based on the ratio of a first capacity consumption to the rated capacity of the battery pack; performing a difference calculation on the initial state of charge value and the first state of charge change to obtain an intermediate state of charge value; and determining the current state of charge value based on the intermediate state of charge value.

[0073] In some examples, the rated capacity value is the maximum usable battery capacity under full charge as specified by the manufacturer, a fixed and unchanging inherent parameter of the battery itself. For example, the lithium iron phosphate power battery pack adapted for new energy passenger vehicles has a factory-specified fully usable capacity of 120 Ah, which is the rated capacity value of the battery pack. The first state of charge change is the decrease in the state of charge of the power battery pack due to power consumption from driving low-voltage electrical equipment during a complete statistical period when the target vehicle is in a preset low-power operating condition. The battery management system can retrieve the statistically completed first capacity consumption and the rated capacity value of the battery pack, and quantify the proportion of battery power consumption by calculating the ratio between the two, thereby obtaining a precise change in power. For example, if the first capacity consumption of the battery pack is 2 Ah and the rated capacity value is 120 Ah during a single low-power statistical period, the calculated power decrease ratio of 1.67% is the first state of charge change.

[0074] The intermediate state of charge (SOC) value is a transitional remaining charge parameter initially calculated by the battery management system (BMS) based on the initial charge baseline and the power consumption loss under operating conditions. It is an intermediate calculation result for solving the final charge data. The BMS can retrieve the initial SOC value corresponding to the low-power operating condition and the calculated first SOC change, and subtract the power loss of the current operating condition through difference calculation to obtain the remaining battery charge value in the transitional state. For example, when the vehicle enters the low-power operating condition, the initial SOC value is 90%. After deducting the first SOC change of 1.67%, the calculated remaining charge value of 88.33% is the intermediate SOC value.

[0075] The process of determining the current state of charge (SOC) based on the intermediate SOC value relies on the accurately calculated intermediate SOC value to confirm the final power result. The transitional power parameter after the operating condition settlement is determined as the current actual remaining power of the battery pack. For example, the battery management system directly confirms the calculated intermediate SOC value of 88.33% as the remaining power of the battery after the settlement of this low-power operating condition, which is the current SOC value.

[0076] By implementing the above embodiments, the capacity consumption is associated with the battery's rated capacity and updated recursively in conjunction with the initial state of charge, thus realizing a dynamic correction mechanism for SOC. This mechanism can continuously reflect the actual changes in battery capacity, avoid the problem of continuous error accumulation in traditional methods, avoid the small current acquisition error in the high-voltage circuit, and effectively improve the problem of insufficient accuracy and error accumulation in battery state of charge estimation under low power consumption conditions, thereby improving the continuity and reliability of SOC estimation results.

[0077] In some embodiments, the aforementioned determination of the current state of charge (SOC) value based on an intermediate SOC value may include: when the DC-DC converter is in operation, determining the intermediate SOC value as the current SOC value; when the DC-DC converter is in sleep mode, compensating the high-voltage circuit current of the battery pack based on the power consumption acquisition error rate, and correcting the intermediate SOC value based on the integrated value of the compensated current to obtain the current SOC value, wherein the power consumption acquisition error rate is used to characterize the zero-drift characteristics of the high-voltage circuit current sensor under a preset low-power operating condition.

[0078] In some examples, the battery management system can identify the operating status signal of the DC-DC converter in real time. If the identification device is in a state of continuous power-on operation and normal power consumption data collection, the intermediate state of charge value obtained from the previous steps can be directly used as the final settlement power. For example, if the target vehicle is parked with the sentry activated and the DC-DC converter is continuously working, the system calculates an intermediate state of charge value of 85% through low-voltage side power consumption. The battery management system directly calibrates this value as the current state of charge value of the current battery pack.

[0079] When the DC-DC converter enters sleep mode, the device stops sampling and statistically analyzing low-voltage power consumption, and cannot continue to calculate battery capacity consumption from low-voltage power. At this time, the battery management system retrieves the pre-calibrated power consumption sampling error rate to correct the sleep-condition current data collected by the high-voltage circuit current sensor, offsetting the sampling deviation caused by zero drift of the high-voltage sensor, and thus completing the calculation of the remaining battery power to obtain an accurate current state of charge value. For example, if the target vehicle is parked and the DC-DC converter is in sleep mode, there is only a weak static current in the high-voltage circuit. The battery management system calls the pre-calibrated power consumption sampling error rate to correct the high-voltage sampling current. After the correction is completed, the real-time remaining battery power is calculated, which is the current state of charge value.

[0080] The power consumption acquisition error rate is an error calibration parameter specifically adapted to preset low-power operating conditions. It is used to quantify the data deviation of the high-voltage circuit current sensor under low-current quiescent conditions, accurately characterizing the zero-drift characteristics of the high-voltage circuit current sensor. The power consumption acquisition error rate reflects the deviation ratio between the high-voltage current sampling data and the actual battery power consumption data, and is an important basis for realizing the current error correction in the dormant operating condition. The power consumption acquisition error rate can be obtained by comparing and calibrating the accurate power consumption data on the low-voltage side with the sampling data on the high-voltage side during the effective statistical period when the vehicle is operating with the DC-DC converter. For example, if the battery power consumption sampled and statistically analyzed by the high-voltage circuit current sensor under preset low-power operating conditions is consistently greater than the actual battery power consumption value, the ratio of the data deviation between the two is the power consumption acquisition error rate corresponding to this operating condition.

[0081] For example, during the complete low-power operation cycle of the target vehicle, the battery management system continuously monitors the operating status of the DC-DC converter, distinguishes between the device's working and dormant scenarios, and calls the corresponding state of charge calculation logic for different scenarios to achieve full coverage of power estimation in low-power scenarios. When the DC-DC converter is working, it completes power calculation based on low-voltage high-precision sampling data, and when the device is in dormant, it corrects high-voltage sampling deviation based on calibrated error parameters.

[0082] By implementing the above embodiments, the operating and dormant states of the DC-DC converter are distinguished, and different SOC update strategies are adopted in different scenarios, enabling the vehicle to maintain high accuracy under various low-power conditions. When the DC-DC converter is operating, energy metering results are directly used, and an error compensation mechanism is introduced when it is in dormant mode, ensuring the continuity and stability of SOC estimation under different energy path conditions. Through differentiated settlement methods, the problems of accumulated state-of-charge errors and poor estimation accuracy in low-power conditions of new energy vehicles are comprehensively improved.

[0083] In some embodiments, the aforementioned compensation of the high-voltage circuit current of the battery pack based on the power consumption acquisition error rate and correction of the intermediate state of charge value based on the compensated current integral value to obtain the current state of charge value when the DC-DC converter is in a dormant state may include: acquiring a second current sampling value of the target vehicle's high-voltage circuit current sensor each time it is sampled during the period when the DC-DC converter is in a dormant state, wherein the high-voltage circuit current sensor is installed in the high-voltage circuit of the battery pack to collect current data of the high-voltage circuit; compensating the second current sampling value based on the power consumption acquisition error rate to obtain a third current sampling value; performing time integration processing on the third current sampling value during the period when the DC-DC converter is in a dormant state to obtain a second state of charge change; and performing a difference calculation between the intermediate state of charge value of the DC-DC converter at the start of the dormant state and the second state of charge change to obtain the current state of charge value.

[0084] The corresponding compensation and integral calculation formulas are as follows:

[0085]

[0086] in, This is the third current sampling value. This is the second current sampling value. The power consumption data collection error rate. This represents the total number of samples taken during the dormancy period. This represents the change in the second state of charge.

[0087] In some examples, the high-voltage circuit current sensor is a dedicated acquisition device integrated into the high-voltage output circuit of the power battery pack. It is used to collect the current data of the high-voltage power supply link of the vehicle in real time and provide raw electrical parameters for battery power calculation. For example, the Hall-effect current acquisition device arranged in the main circuit of the high-voltage positive terminal of the power battery can collect the discharge current and the weak static current of the high-voltage circuit around the clock.

[0088] The second current sampling value is the real-time current data of the high-voltage circuit collected by the high-voltage circuit current sensor according to a fixed sampling period during the time when the DC-DC converter enters the dormant working state. It is used to characterize the real-time discharge current of the battery pack when the converter is in a dormant and stationary state. For example, when the target vehicle is parked and stationary and the DC-DC converter stops working and enters the dormant state, the high-voltage circuit generates a weak static self-discharge current of 0.4 amperes. This instantaneous current value is the second current sampling value.

[0089] The third current sampling value is the equivalent true current parameter of the high-voltage circuit after error correction. It is the accurate current data after eliminating the zero drift error of the high-voltage circuit current sensor, which can truly reflect the actual discharge current of the power battery pack. For example, the original high-voltage sampling current has a positive zero drift deviation. After error compensation correction, a weak current value that is closer to the actual power consumption of the battery is obtained. This corrected current is the third current sampling value.

[0090] The second state-of-charge change is the overall power loss amplitude of the power battery pack due to the weak self-discharge of the high-voltage circuit during the complete period of continuous dormancy of the DC-DC converter. It is used to quantify the scale of power consumption of the battery when the converter is in dormancy and to correct the remaining power of the battery during the dormancy process. For example, if the DC-DC converter is in dormancy for 30 minutes, the proportion of power loss caused by the continuous weak self-discharge of the power battery pack is the second state-of-charge change corresponding to this dormancy cycle.

[0091] The intermediate state of charge (SBC) value at the start of the dormant state is the baseline value for calculating the remaining charge during this resting period. The second SBC change is the amount of charge loss generated during the resting process. The battery management system subtracts the amount of charge lost during resting from the baseline charge value to complete the iterative update of the charge under the resting condition, and then outputs the final accurate remaining battery charge data. For example, if the intermediate SBC value of the DC-DC converter when it enters the dormant state is 83%, after deducting the 0.5% charge loss generated during the dormant period, the final calculated remaining battery charge is the current SBC value.

[0092] For example, the battery management system monitors the working status of the DC-DC converter in real time, and immediately switches the power calculation logic after the device enters a sleep state; it continuously collects the original current data of the high-voltage circuit and completes accurate current compensation by combining the previously calibrated error parameters; it fully calculates the battery power loss during the resting stage through time integration, and completes the remaining power update based on accurate difference calculation.

[0093] By implementing the above embodiments, during the DC-DC converter's sleep period, by performing error compensation on the high-voltage side current sampling value and then performing integration calculation, the zero drift problem of the current sensor under low current conditions can be effectively corrected, so that even in the absence of low-voltage side energy data, error accumulation can still be reduced and the accuracy level of SOC estimation can be maintained.

[0094] In some embodiments, before compensating the second current sample value based on the power consumption acquisition error rate to obtain the third current sample value, the battery state of charge determination method may further include: acquiring the fourth current sample value and the third voltage sample value of each sampling by the high-voltage circuit current sensor within a statistical period; determining the second capacity consumption of the battery pack based on the fourth current sample value and the third voltage sample value; and determining the power consumption acquisition error rate based on the first capacity consumption and the second capacity consumption.

[0095] In some examples, the fourth current sampling value is the raw current data of the high-voltage circuit periodically collected by the high-voltage circuit current sensor during a statistical period when the target vehicle is in a preset low-power operating condition and the DC-DC converter is working normally. The fourth current sampling value can be controlled by the battery management system to synchronously start the periodic current acquisition of the high-voltage circuit current sensor during the same statistical period when the DC-DC converter is conducting low-voltage power consumption sampling, so as to ensure that the high and low voltage sampling timing is completely synchronized. For example, during the statistical period of the vehicle parking sentry condition, the 0.3 ampere high-voltage discharge current collected by the high-voltage circuit current sensor at fixed sampling intervals is the fourth current sampling value corresponding to a single sampling.

[0096] The third voltage sampling value is the real-time voltage data of the high-voltage port of the power battery pack synchronously collected by the battery management system during the statistical period corresponding to the preset low-power operating condition. This voltage parameter is used to match the fourth current sampling value to complete the conversion between high-voltage side power consumption and capacity consumption, and is independent of the low-voltage side voltage sampling parameter. The third voltage sampling value can be obtained by the battery management system at the same time as the high-voltage circuit current sensor completes the acquisition of the fourth current sampling value, reading the real-time operating voltage at both ends of the high voltage of the battery pack, so as to realize the time-series alignment of current parameters and voltage parameters. For example, in a single node of high and low voltage synchronous sampling, the battery management system collects the high-voltage operating voltage of the power battery pack as 310 volts, and this voltage value is the third voltage sampling value corresponding to this sampling.

[0097] The second capacity consumption is the total battery pack capacity consumption calculated based on the traditional sampling algorithm of the high-voltage circuit. It represents the low-power battery power consumption capacity calculated by the high-voltage circuit current sensor based on its own sampling data. This parameter is used to compare with the accurate capacity data obtained by the DC-DC converter, thereby inversely deducing the sampling error of the high-voltage device. The battery management system can integrate all the fourth current sampling values ​​and third voltage sampling values ​​within the statistical period, and summarize them through high-voltage side energy integration and capacity conversion logic to obtain the second capacity consumption of the battery pack within the complete statistical period. For example, within a 10-minute low-power statistical period, based on the calculation and summary of all high-voltage side sampling data, the battery pack capacity consumption is 0.8 amp-hours, and this capacity value is the second capacity consumption.

[0098] The first capacity consumption is the actual battery capacity consumption calculated using high-precision sampling from the DC-DC converter, which can be used as a standard benchmark. The second capacity consumption is the deviation capacity data from the high-voltage side sampling statistics. By comparing and calculating the two sets of capacity data, the inherent sampling deviation of the high-voltage circuit current sensor under low-power conditions can be accurately quantified, generating a specific power consumption acquisition error rate. For example, if the actual battery capacity consumption calculated from the low-voltage side is 0.75 AH and the capacity consumption calculated from the high-voltage side is 0.8 AH, the difference calculation shows that the high-voltage side capacity consumption deviation during this statistical period is 0.05 AH. Dividing this capacity consumption deviation by the complete statistical duration of this low-power condition allows for the accurate calculation of the power consumption acquisition error rate corresponding to the high-voltage sampling under this condition.

[0099] By implementing the above embodiments, high-voltage side current and voltage data can be acquired simultaneously during the operation of the DC-DC converter and compared with the capacity consumption calculated on the low-voltage side. This enables the establishment of an error assessment mechanism, which can quantify the deviation of high-voltage current acquisition, provide a basis for subsequent compensation, and improve the overall system's adaptability to sensor errors.

[0100] In some embodiments, the aforementioned determination of the power consumption collection error rate based on the first capacity consumption and the second capacity consumption may include: performing a difference calculation on the second capacity consumption and the first capacity consumption to obtain a capacity consumption deviation; and determining the ratio of the capacity consumption deviation to the duration of the statistical period as the power consumption collection error rate.

[0101] In some examples, the capacity consumption deviation is the difference between the sampled capacity of the high-voltage circuit and the actual battery consumption capacity within a single complete statistical period. This directly reflects the overall sampling error of the high-voltage circuit current sensor under low-power conditions. For instance, if the second capacity consumption obtained from the high-voltage side is 0.8 AH and the first capacity consumption obtained from the low-voltage side is 0.75 AH within a single preset low-power statistical period, the 0.05 AH difference between the two sets of data is the capacity consumption deviation for this operating condition. The battery management system can read the duration of this effective statistical period and perform a ratio calculation based on the calculated capacity consumption deviation to generate a reusable standardized error parameter. For example, if the total duration of the statistical period is 600 seconds, the ratio calculation based on the 0.05 AH capacity consumption deviation yields the capacity sampling deviation of the high-voltage circuit current sensor per unit time. This normalized parameter is the power consumption acquisition error rate.

[0102] By implementing the above embodiments, the capacity consumption deviation and time are normalized to obtain an error rate index that reflects the error characteristics per unit time. This makes the error quantifiable and applicable, facilitating the uniform use of the error parameter for compensation under different operating conditions, and improving the stability and versatility of error correction.

[0103] In some embodiments, the aforementioned compensation processing of the second current sample value based on the power consumption acquisition error rate to obtain the third current sample value may include: performing temperature correction on the power consumption acquisition error rate based on the ambient temperature information of the target vehicle to obtain the target acquisition error rate; and performing compensation processing on the second current sample value based on the target acquisition error rate to obtain the third current sample value.

[0104] In some examples, the ambient temperature information is the real-time temperature parameter of the external environment where the target vehicle is currently located. The zero-drift characteristics of the high-voltage loop current sensor will change with the ambient temperature, thus affecting the sampling accuracy of the high-voltage current. The ambient temperature information is used to dynamically correct the original calibrated power consumption acquisition error rate and eliminate the error calibration failure problem caused by temperature changes. For example, the -10 degrees Celsius temperature data corresponding to the target vehicle being parked in a low-temperature outdoor environment, or the 25 degrees Celsius temperature data corresponding to a normal-temperature garage environment, are both considered real-time ambient temperature information collected by the vehicle.

[0105] The target acquisition error rate is a dynamic error parameter obtained by combining the original power consumption acquisition error rate with real-time ambient temperature information. It can accurately adapt to the true zero-drift characteristics of the high-voltage circuit current sensor under the current temperature environment. Unlike the fixed original error parameter, the target acquisition error rate can be dynamically updated with the ambient temperature to adapt to the low-power compensation requirements of the entire temperature range. For example, the original power consumption acquisition error rate is a fixed value under normal temperature conditions. When the vehicle is in a low-temperature environment, the system performs correction calculations based on the current ambient temperature to generate a new error parameter adapted to the low-temperature condition. This corrected error parameter is the target acquisition error rate.

[0106] The second current sample value is the raw current data collected by the high-voltage circuit during the DC-DC converter's sleep mode, which includes the device zero-drift error corresponding to the current temperature. Relying on the more accurate target acquisition error rate after temperature correction, it can specifically offset the current sampling deviation under different temperature environments, and obtain current parameters that closely match the actual discharge state of the power battery. The battery management system can retrieve the target acquisition error rate updated in real time and perform deviation compensation and correction on each second current sample value obtained during the sleep period. For example, when the vehicle is in a low-temperature parking and stationary condition, the target acquisition error rate after low-temperature correction is called to offset the deviation of the weak stationary current originally collected by the high-voltage circuit, and finally obtain the true current data that eliminates the temperature zero-drift error, which is the third current sample value.

[0107] By implementing the above embodiments, the ambient temperature is introduced to correct the error rate, which can take into account the impact of temperature on the current sensor and system performance, making the error compensation more in line with the actual working conditions. This can improve the adaptability of SOC estimation under different environmental conditions, comprehensively improve the estimation accuracy and stability of the remaining battery power under low power conditions in different environments, and thus further improve the overall estimation accuracy.

[0108] In some embodiments, the battery pack is a lithium iron phosphate battery pack.

[0109] In some examples, lithium iron phosphate battery packs are integrated power battery assemblies assembled with lithium iron phosphate as the positive electrode substrate. They are energy storage devices adapted to the high-voltage power supply system of new energy vehicles, and can continuously provide high-voltage power output for vehicle driving and low-voltage auxiliary electrical equipment operation. Compared with other battery systems, lithium iron phosphate battery packs have the characteristics of stable voltage platform, long cycle life and high safety and stability.

[0110] During normal operation, the voltage values ​​of lithium iron phosphate (LFP) battery packs are highly consistent across most of their state of charge (SOC) ranges, with minimal voltage fluctuations as the battery capacity decreases. Therefore, SOC calibration cannot rely on voltage fluctuations. Traditional SOC estimation methods based on voltage changes are ill-suited to the inherent characteristics of LFP battery packs, easily leading to continuous accumulation of power errors under low-power conditions. This application's embodiments abandon traditional voltage calibration and fixed-coefficient compensation schemes. Instead, it utilizes a DC-DC converter to accurately collect low-voltage power consumption data under low-power conditions. By applying the principle of energy conservation, it calculates high-voltage battery capacity consumption and independently performs iterative SOC calculations. This completely avoids the calibration limitations caused by the voltage platform characteristics of LFP batteries, adapting to the low-power power estimation needs across the entire SOC range of LFP battery packs. This significantly improves the accuracy of SOC calculations in scenarios such as parking and standby in LFP vehicle models.

[0111] Through the implementation of the above embodiments, since the voltage of lithium iron phosphate battery packs does not change significantly in most operating ranges, the traditional voltage-based calibration method has limited effectiveness. However, the embodiments of this application can effectively make up for this deficiency by combining energy measurement and error compensation, thereby showing a more significant accuracy advantage in lithium iron phosphate battery pack application scenarios.

[0112] Furthermore, as an implementation of the aforementioned method embodiments, this application also provides a battery state of charge determination device for implementing the aforementioned method embodiments. This device embodiment corresponds to the aforementioned method embodiments. For ease of reading, this battery state of charge determination device embodiment will not repeat the details of the aforementioned method embodiments one by one, but it should be understood that the device in this application embodiment can correspondingly implement all the contents of the aforementioned method embodiments. For example... Figure 2 As shown, the battery state of charge determination device 20 includes: a state of charge acquisition unit 201, a cumulative power consumption acquisition unit 202, a capacity consumption determination unit 203, and a state of charge determination unit 204. The state of charge acquisition unit 201 acquires the state of charge value at the start of the target vehicle entering a preset low-power operating condition, serving as the initial state of charge value of the target vehicle's battery pack. The cumulative power consumption acquisition unit 202 acquires the cumulative power consumption collected by the target vehicle's DC-DC converter under the preset low-power operating condition. The DC-DC converter is connected to the battery pack 203 and provides power to the target vehicle's low-voltage electrical equipment. The capacity consumption determination unit 204 determines the first capacity consumption of the battery pack based on the cumulative power consumption. The state of charge determination unit 205 determines the current state of charge value of the battery pack under the preset low-power operating condition based on the first capacity consumption and the initial state of charge value.

[0113] In some embodiments, the state of charge acquisition unit 201 is further configured to acquire the operating status information of the target vehicle and the output current of the battery pack; when the operating status information indicates that the target vehicle is in a parked state and the output current is less than a preset current threshold, the target vehicle is determined to have entered a preset low power consumption condition.

[0114] In some embodiments, the cumulative power consumption acquisition unit 202 is further configured to acquire the first current sampling value and the first voltage sampling value of the DC converter for each sampling within a statistical period, wherein the statistical period is the period during which the target vehicle is in a preset low power consumption condition and the DC converter is in a working state; the first current sampling value and the first voltage sampling value corresponding to each sampling within the statistical period are multiplied and accumulated to obtain the cumulative power consumption.

[0115] In some embodiments, the capacity consumption determination unit 204 is further configured to acquire the second voltage sample value of the DC-DC converter for each sampling within a statistical period, and the power consumption within the sampling interval of each sampling; for each sampling within the statistical period, based on the ratio of the power consumption within the sampling interval of that sampling to the second voltage sample value of that sampling, determine the unit capacity consumption within the sampling interval of that sampling; and accumulate the unit capacity consumption corresponding to each sampling within the statistical period to obtain the first capacity consumption.

[0116] In some embodiments, the state of charge determination unit 205 is further configured to determine a first state of charge change based on the ratio of the first capacity consumption to the rated capacity of the battery pack; perform a difference calculation on the initial state of charge value and the first state of charge change to obtain an intermediate state of charge value; and determine the current state of charge value based on the intermediate state of charge value.

[0117] In some embodiments, the state of charge determination unit 205 is further configured to determine the intermediate state of charge value as the current state of charge value when the DC-DC converter is in operation; and to compensate the high-voltage circuit current of the battery pack based on the power consumption acquisition error rate when the DC-DC converter is in sleep mode, and to correct the intermediate state of charge value based on the compensated current integral value to obtain the current state of charge value, wherein the power consumption acquisition error rate is used to characterize the zero-drift characteristics of the high-voltage circuit current sensor under a preset low power consumption condition.

[0118] In some embodiments, the state of charge determination unit 205 is further configured to acquire a second current sampling value from the high-voltage circuit current sensor of the target vehicle each time it is sampled during the period when the DC-DC converter is in a dormant state, wherein the high-voltage circuit current sensor is disposed in the high-voltage circuit of the battery pack and is used to collect current data of the high-voltage circuit; to compensate the second current sampling value based on the power consumption acquisition error rate to obtain a third current sampling value; to perform time integration processing on the third current sampling value during the period when the DC-DC converter is in a dormant state to obtain a second state of charge change; and to perform a difference calculation between the intermediate state of charge value of the DC-DC converter at the beginning of the dormant state and the second state of charge change to obtain the current state of charge value.

[0119] In some embodiments, the state of charge determination unit 205 is further configured to acquire the fourth current sampling value and the third voltage sampling value of the high-voltage loop current sensor each time during the statistical period; determine the second capacity consumption of the battery pack based on the fourth current sampling value and the third voltage sampling value; and determine the power consumption acquisition error rate based on the first capacity consumption and the second capacity consumption.

[0120] In some embodiments, the state of charge determination unit 205 is further configured to perform a difference calculation between the second capacity consumption and the first capacity consumption to obtain a capacity consumption deviation; and to determine the ratio of the capacity consumption deviation to the duration of the statistical period as the power consumption acquisition error rate.

[0121] In some embodiments, the state of charge determination unit 205 is further configured to perform temperature correction on the power consumption acquisition error rate based on the ambient temperature information of the target vehicle to obtain a target acquisition error rate; and to perform compensation processing on the second current sample value based on the target acquisition error rate to obtain a third current sample value.

[0122] In some embodiments, the battery pack is a lithium iron phosphate battery pack.

[0123] This application also provides a computer-readable storage medium storing computer-executable instructions or computer programs, which, when executed by a processor, will cause the processor to perform any step of the battery state-of-charge determination method provided in this application.

[0124] In some embodiments, the computer-readable storage medium may be a random access memory (RAM), a read-only memory (ROM), flash memory, a magnetic surface memory, an optical disc, or a compact disc read-only memory (CD-ROM); or it may be a variety of devices that include one or any combination of the above-mentioned memories.

[0125] In some embodiments, computer-executable instructions may take the form of programs, software, software modules, scripts, or code, written in any form of programming language (including compiled or interpreted languages, or declarative or procedural languages), and may be deployed in any form, including as stand-alone programs or as modules, components, subroutines, or other units suitable for use in a computing environment.

[0126] In some embodiments, computer-executable instructions may, but do not necessarily, correspond to files in a file system, and may be stored as part of a file that holds other programs or data, for example, in one or more scripts in a HyperText Markup Language (HTML) document, in a single file dedicated to the program in question, or in multiple co-located files (e.g., files that store one or more modules, subroutines, or code sections).

[0127] In some embodiments, computer-executable instructions may be deployed to execute on a single vehicle, or on multiple vehicles located at a single location, or on multiple vehicles distributed across multiple locations and interconnected via a communication network.

[0128] like Figure 3 As shown, this application also provides a vehicle 30, including a memory 310, a processor 320, and a computer program 311 stored in the memory 310 and executable on the processor. When the processor 320 executes the computer program 311, it implements any step of the above-described battery state of charge determination method.

[0129] This application also provides a computer program product comprising a computer program or computer-executable instructions stored in a computer-readable storage medium. A vehicle's processor reads the computer program or computer-executable instructions from the computer-readable storage medium and executes the computer program or computer-executable instructions, causing the vehicle to perform any step of the battery state-of-charge determination method described above.

[0130] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for determining the state of charge of a battery, characterized in that, Applied to the target vehicle, the battery state of charge determination method includes: The state of charge (SOC) value at the start of the target vehicle entering the preset low-power operating condition is obtained as the initial SOC value of the target vehicle's battery pack. The cumulative power consumption of the target vehicle is collected by the DC-DC converter of the target vehicle under the preset low power consumption condition, wherein the DC-DC converter is connected to the battery pack and is used to provide power to the low-voltage electrical equipment of the target vehicle. Based on the cumulative power consumption, the first capacity consumption of the battery pack is determined; Based on the first capacity consumption and the initial state of charge value, the current state of charge value of the battery pack under the preset low power consumption condition is determined.

2. The method for determining the state of charge of a battery according to claim 1, characterized in that, The method for determining the state of charge of the battery also includes: Obtain the operating status information of the target vehicle and the output current of the battery pack; If the operating status information indicates that the target vehicle is in a parked state and the output current is less than a preset current threshold, then the target vehicle is determined to have entered the preset low-power operating condition.

3. The method for determining the state of charge of a battery according to claim 1, characterized in that, The step of obtaining the cumulative power consumption of the target vehicle under the preset low-power operating condition, collected by the DC-DC converter of the target vehicle, includes: The first current sample value and the first voltage sample value of the DC converter are obtained for each sampling within a statistical period, wherein the statistical period is the period during which the target vehicle is in the preset low power consumption condition and the DC converter is in the working state; The cumulative power consumption is obtained by multiplying the first current sample value and the first voltage sample value corresponding to each sampling within the statistical period and then summing them.

4. The method for determining the state of charge of a battery according to claim 3, characterized in that, Determining the first capacity consumption of the battery pack based on the cumulative power consumption includes: The second voltage sample value of the DC converter is obtained for each sampling within the statistical period, and the power consumption within the sampling interval of each sampling is also obtained. For each sample within the statistical period, the unit capacity consumption within the sampling interval is determined based on the ratio of the power consumption within the sampling interval to the second voltage sample value of the sampling. The unit capacity consumption corresponding to each sampling within the statistical period is accumulated to obtain the first capacity consumption.

5. The method for determining the state of charge of a battery according to claim 1, characterized in that, Determining the current state of charge (SOC) of the battery pack under the preset low-power operating condition based on the first capacity consumption and the initial SOC value includes: The first change in state of charge is determined based on the ratio of the first capacity consumption to the rated capacity of the battery pack. The difference between the initial state of charge value and the first state of charge change is calculated to obtain the intermediate state of charge value. The current state of charge is determined based on the intermediate state of charge value.

6. The method for determining the state of charge of a battery according to claim 5, characterized in that, Determining the current state of charge value based on the intermediate state of charge value includes: When the DC-DC converter is in operation, the intermediate state of charge value is determined as the current state of charge value; When the DC-DC converter is in a dormant state, the high-voltage circuit current of the battery pack is compensated based on the power consumption acquisition error rate, and the intermediate state of charge value is corrected based on the integrated value of the compensated current to obtain the current state of charge value. The power consumption acquisition error rate is used to characterize the zero-drift characteristic of the high-voltage circuit current sensor under the preset low power consumption condition.

7. The method for determining the state of charge of a battery according to claim 6, characterized in that, When the DC-DC converter is in a dormant state, the high-voltage circuit current of the battery pack is compensated based on the power consumption acquisition error rate, and the intermediate state of charge value is corrected based on the compensated current integral value to obtain the current state of charge value, including: During the period when the DC-DC converter is in the dormant state, the second current sampling value of the high-voltage circuit current sensor of the target vehicle is obtained each time, wherein the high-voltage circuit current sensor is set in the high-voltage circuit of the battery pack and is used to collect the current data of the high-voltage circuit; The second current sample value is compensated based on the power consumption acquisition error rate to obtain the third current sample value. The third current sample value is integrated over time during the period when the DC-DC converter is in the sleep state to obtain the second state of charge change. The current state of charge value is obtained by performing a difference calculation between the intermediate state of charge value of the DC-DC converter at the start of the dormant state and the second state of charge change.

8. The method for determining the state of charge of a battery according to claim 7, characterized in that, Before compensating the second current sample value based on the power consumption acquisition error rate to obtain the third current sample value, the battery state of charge determination method further includes: Obtain the fourth current sampling value and the third voltage sampling value of each sampling by the high-voltage circuit current sensor during the statistical period; Based on the fourth current sampling value and the third voltage sampling value, the second capacity consumption of the battery pack is determined; The difference between the second capacity consumption and the first capacity consumption is calculated to obtain the capacity consumption deviation. The ratio of the capacity consumption deviation to the duration of the statistical period is determined as the power consumption collection error rate.

9. The method for determining the state of charge of a battery according to claim 7, characterized in that, The process of compensating the second current sample value based on the power consumption acquisition error rate to obtain the third current sample value includes: Based on the ambient temperature information of the target vehicle, the power consumption acquisition error rate is corrected for temperature to obtain the target acquisition error rate. The second current sample value is compensated based on the target acquisition error rate to obtain the third current sample value.

10. A battery state of charge determination device, characterized in that, Applied to the target vehicle, the battery state of charge determination device includes: The state of charge acquisition unit is used to acquire the state of charge value at the start time when the target vehicle enters the preset low power consumption condition, and use it as the initial state of charge value of the battery pack of the target vehicle. The cumulative power consumption acquisition unit is used to acquire the cumulative power consumption of the target vehicle collected by the DC-DC converter of the target vehicle under the preset low power consumption condition, wherein the DC-DC converter is connected to the battery pack and is used to provide power to the low-voltage electrical equipment of the target vehicle. A capacity consumption determination unit is used to determine a first capacity consumption of the battery pack based on the cumulative power consumption; A state of charge determination unit is used to determine the current state of charge value of the battery pack under the preset low power consumption condition based on the first capacity consumption and the initial state of charge value.

11. A vehicle comprising: A memory and a processor, characterized in that the processor, when executing a computer program stored in the memory, implements the steps of the battery state of charge determination method as described in any one of claims 1 to 9.

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