Battery management system, soc correction method thereof, and computer readable storage medium

Abstract

The application discloses a battery management system and an SOC correction method thereof and a computer readable storage medium, wherein the SOC correction method of the battery management system comprises the following steps: acquiring a power-on time, a power-off time and a T-BOX time; wherein the power-on time is the time of a real-time clock module when the battery management system is powered on this time, the power-off time is the time when the battery management system is powered off last time, and the T-BOX time is the time of a T-BOX system; calibrating the power-on time according to the T-BOX time; and determining an SOC correction trigger strategy according to the calibration result of the power-on time. In the manner, the SOC correction can be triggered accurately.

Description

Technical Field

[0001] This application relates to the field of battery management technology, and in particular to a battery management system and its SOC correction method, and a computer-readable storage medium. Background Technology

[0002] Battery Management Systems (BMS) are commonly used in electric vehicles and are embedded electronic products. They all include an RTC (Real-Time Clock) module, and most BMS also have an auxiliary power supply to power the RTC module. This is usually achieved using energy storage media such as button batteries or supercapacitors. The role of the RTC power supply is to ensure that the BMS can continue to operate the system clock for a short period of time in the event of a loss of the constant power supply. The timing of the next power-on will not deviate significantly from the previous power-off time, so that some algorithms and functions can continue to execute normally, such as data logging functions and battery system SOC correction functions.

[0003] If the RTC's power is depleted or malfunctions, it will be unable to maintain the real-time clock function when the BMS is completely disconnected from power. This will cause the absolute time of the BMS to become disordered when it is powered on again, thereby affecting the battery system's SOC static OCV correction function. This may affect the accuracy of the SOC calculation after the power-on, and in severe cases, it may result in an artificially high or low SOC, affecting the driver's driving experience and causing the vehicle to break down on the road. Summary of the Invention

[0004] To address the aforementioned issues, this application provides a battery management system and its SOC correction method, as well as a computer-readable storage medium, which can resolve the issue of SOC correction being triggered due to RTC malfunction in related technologies.

[0005] One technical solution adopted in this application is: providing a SOC correction method for a battery management system, the method comprising: acquiring the power-on time and T-BOX time; wherein, the power-on time is the time of the real-time clock module when the battery management system is powered on for the current time, and the T-BOX time is the time of the T-BOX system; calibrating the power-on time according to the T-BOX time; and determining the SOC correction triggering strategy according to the calibration result of the power-on time.

[0006] In one embodiment, calibrating the power-on time based on the T-BOX time includes: determining a first time difference between the T-BOX time and the power-on time; and calibrating the power-on time to the T-BOX time in response to the first time difference being greater than a set time threshold.

[0007] In one embodiment, before calibrating the power-on time based on the T-BOX time, the method further includes: determining whether the T-BOX time is valid; and, in response to the T-BOX time being valid, performing a step of calibrating the power-on time based on the T-BOX time.

[0008] In one embodiment, a SOC correction triggering strategy is determined based on the calibration result of the power-on time, including: in response to successful power-on time calibration, determining a second time difference between the power-on time and the power-off time, and determining the SOC correction triggering strategy based on the second time difference; wherein, the power-off time is the time of the previous power-off of the battery management system; in response to failed power-on time calibration, a battery resting temperature strategy is used for SOC correction.

[0009] In one embodiment, the method further includes: acquiring the time of the real-time clock module based on a preset time interval and storing it as the power-off time.

[0010] In one embodiment, the method further includes: in response to the power-down mode of the battery management system being low-voltage power-down, acquiring the time of the real-time clock module at the time of power-down and storing it as the power-down time.

[0011] In one embodiment, determining the SOC correction triggering strategy based on the second time difference includes: in response to the second time difference meeting a preset requirement, using a battery resting time strategy to perform SOC correction; or in response to the second time difference not meeting the preset requirement, using a battery resting temperature strategy to perform SOC correction.

[0012] In one embodiment, a battery resting temperature strategy is used for SOC correction, including: obtaining a power-on temperature value and a power-off temperature value; wherein the power-on temperature value is the battery temperature of the battery management system when it is powered on for the current time, and the power-off temperature value is the battery temperature of the battery management system when it was powered off for the previous time; determining the temperature difference between the power-on temperature value and the power-off temperature value; and in response to the temperature difference being greater than a set temperature threshold, using the battery resting temperature strategy to correct the SOC.

[0013] Another technical solution adopted in this application is to provide a battery management system, which includes a processor and a memory, wherein the memory is used to store program data and the processor is used to execute the program data to implement the method described above.

[0014] Another technical solution adopted in this application is to provide a computer-readable storage medium that stores program data, which, when executed by a processor, is used to implement the method described above.

[0015] The SOC correction method for a battery management system provided in this application includes: acquiring the power-on time and T-BOX time; wherein, the power-on time is the time of the real-time clock module when the battery management system is powered on, and the T-BOX time is the time of the T-BOX system; calibrating the power-on time based on the T-BOX time; and determining the SOC correction trigger strategy based on the calibration result of the power-on time. By using the T-BOX time to calibrate the RTC time and select the corresponding SOC correction trigger strategy, on the one hand, the RTC time can be calibrated even when the RTC is not powered, and even without providing a separate auxiliary power supply to the RTC; on the other hand, the SOC correction triggering method can be determined based on the time calibration results, avoiding the problem of SOC correction not triggering in certain situations or triggering continuously. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0017] Figure 1 This is a flowchart illustrating an embodiment of the SOC correction method for the battery management system provided in this application;

[0018] Figure 2 yes Figure 1 A flowchart illustrating an embodiment of step 12;

[0019] Figure 3 yes Figure 1 A flowchart of an embodiment of step 13;

[0020] Figure 4 yes Figure 3 A flowchart of an embodiment of step 131;

[0021] Figure 5 This is a schematic diagram of the structure of an embodiment of the battery management system provided in this application;

[0022] Figure 6 This is a schematic diagram of an embodiment of the computer-readable storage medium provided in this application. Detailed Implementation

[0023] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It is understood that the specific embodiments described herein are only for explaining this application and not for limiting it. Furthermore, it should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings, not all structures. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0024] The terms "first," "second," etc., used in this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0025] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0026] See Figure 1 , Figure 1 This is a flowchart illustrating an embodiment of the SOC correction method for a battery management system provided in this application. The method includes:

[0027] Step 11: Obtain the power-on time and T-BOX time; where the power-on time is the real-time clock module time when the battery management system is powered on, and the T-BOX time is the time of the T-BOX system.

[0028] The battery management system (BMS), commonly known as a battery nanny or battery manager, is primarily designed for the intelligent management and maintenance of individual battery cells. It prevents overcharging and over-discharging, extends battery life, and monitors battery status. A typical BMS consists of multiple battery boxes and a high-voltage box. Each battery box contains slave boards for managing the status of batteries within its individual box. The high-voltage box contains a main board that connects to multiple slave boards to manage the entire BMS and connects to the vehicle's control system.

[0029] The T-BOX (Telematics Box, vehicle networking) system comprises four parts: a main unit, an in-vehicle T-BOX, a mobile app, and a backend system. The main unit is primarily used for in-vehicle audio-visual entertainment and vehicle information display; the in-vehicle T-BOX is mainly used to communicate with the backend system / mobile app, enabling vehicle information display and control via the mobile app. Understandably, since the T-BOX system is networked, its timekeeping can be considered accurate.

[0030] In this embodiment, the real-time clock module (RTC module) is not powered by an auxiliary power source. Therefore, the RTC module does not work after the battery management system is powered down. Consequently, when the RTC module is powered on again after the BMS is powered down, the time may be inaccurate. Therefore, the time of the RTC module needs to be calibrated.

[0031] Step 12: Calibrate the power-on time according to the T-BOX time.

[0032] Understandably, since the T-BOX system is networked, it can be assumed that the time of the T-BOX system is accurate. In this embodiment, the T-BOX time is used to calibrate the time of the RTC module.

[0033] Optionally, such as Figure 2 As shown, Figure 2 yes Figure 1 A flowchart illustrating an embodiment of step 12, which may specifically include:

[0034] Step 121: Determine if the T-BOX time is valid.

[0035] The determination of whether a T-BOX time is valid is mainly based on whether the data format of the T-BOX time conforms to a standard time format.

[0036] In one embodiment, the conventional time format includes "year, month, day, hour, minute, second". For example, it can be required that the value of "month" does not exceed 12, the value of "day" does not exceed 31, the value of "hour" does not exceed 24, and the values ​​of "minute" and "second" do not exceed 60. If all the aforementioned conditions are met, the T-BOX time is considered to be valid.

[0037] Step 122: In response to the T-BOX time being valid, determine the first time difference between the T-BOX time and the power-on time.

[0038] Step 123: In response to the first time difference being greater than the set time threshold, calibrate the power-on time to the T-BOX time.

[0039] Understandably, the first time difference here is the absolute value of the difference between the T-BOX time and the power-on time, or the power-on time and the T-BOX time. Optionally, this time threshold can be set to 1 minute. If the first time difference is greater than 1 minute, the power-on time obtained by the RTC module can be considered inaccurate, and the power-on time will be calibrated to the T-BOX time. If the first time difference is less than 1 minute, the power-on time obtained by the RTC module can be considered accurate, and the time obtained by the RTC module will be directly used as the power-on time. Understandably, the 1 minute here can also be modified to any other value set according to requirements.

[0040] Step 13: Determine the SOC correction trigger strategy based on the power-on time calibration results.

[0041] Among them, the SOC correction strategies mainly include battery resting time strategy and battery resting temperature strategy.

[0042] The State of Charge (SOC) of a battery refers to the state of its remaining charge, specifically defined as the percentage of remaining charge relative to the full charge capacity. Accurately estimating the SOC is crucial for effective vehicle energy management, preventing damage to the electric vehicle battery, optimizing battery energy utilization, improving battery efficiency, and extending battery pack lifespan. SOC estimation has its own unique characteristics; different temperatures, discharge rates, and SOC points all affect the final value. A higher discharge rate results in less charge being released; excessively high or low operating temperatures reduce usable capacity; and due to aging and self-discharge, the SOC value needs continuous adjustment. Therefore, calculating SOC hinges on estimating the remaining charge capacity relative to the full charge capacity. Current battery SOC estimation strategies primarily include: open-circuit voltage method, ampere-hour integration method, internal resistance method, linear model method, artificial neural network method, Kalman filtering method, and dynamic approximation method.

[0043] The open-circuit voltage method determines the state of charge (SOC) value of a battery based on its open-circuit voltage (OCV). Taking a lithium-ion single cell as an example, its voltage typically reaches around 4.2V when fully charged and around 2.6V when fully discharged. The battery voltage changes continuously during charging and discharging. Research has found a relationship between the battery's open-circuit voltage and its remaining capacity, and data fitting is a commonly used method for this.

[0044] In simple terms, the open-circuit voltage of the battery is measured at different SOC values, and then a function of SOC-OCV is obtained through data fitting.

[0045] The triggering conditions for the open-circuit voltage method generally include a battery resting time strategy and a battery resting temperature strategy. The battery resting time strategy means that the battery resting time needs to meet certain conditions to trigger the open-circuit voltage method for SOC correction. The battery temperature strategy means that the battery resting temperature needs to meet certain conditions to trigger the open-circuit voltage method for SOC correction.

[0046] Optionally, such as Figure 3 As shown, Figure 3 yes Figure 1 A flowchart illustrating an embodiment of step 13, which may specifically include:

[0047] Step 131: In response to the successful power-on time calibration, determine the second time difference between the power-on time and the power-off time, and determine the SOC correction trigger strategy based on the second time difference; wherein, the power-off time is the time of the previous power-off of the battery management system.

[0048] Successful power-on time calibration refers to the power-on time determined by the RTC module when the T-BOX time is valid and the first time difference between the T-BOX time and the power-on time is less than a set time threshold; or the power-on time determined by the T-BOX time when the T-BOX time is valid and the first time difference between the T-BOX time and the power-on time is greater than a set time threshold.

[0049] Alternatively, there are two main ways to obtain the power-off time:

[0050] The first method involves acquiring the time from the real-time clock module (RTC) at preset time intervals and storing it as the power-off time. Specifically, during normal operation after power-on, the battery management system acquires the RTC module's time every preset time interval and stores it as the power-off time. This preset time can be 10 minutes or any value set according to requirements.

[0051] Another approach is to detect whether the various components of the controller have been released and whether the data writing has been completed when the power is turned off. Therefore, when the power is turned off, the time of the RTC module can be obtained and stored as the power-off time.

[0052] Understandably, of the two methods for obtaining power-off time, the former is mainly used in the case of sudden power outage, while the latter is used in the case of low-voltage power-off. The latter is relatively more accurate. If the first method uses a 10-minute acquisition interval, the maximum error between the two methods is only 10 minutes. In order to reduce the error, the acquisition interval of RTC time in the first method can be adjusted according to the requirements.

[0053] Based on a preset time interval, the time of the real-time clock module is obtained and stored as the power-off time.

[0054] Specifically, determining the SOC correction trigger strategy based on the second time difference includes: in response to the second time difference meeting the preset requirements, using a battery resting time strategy to perform SOC correction; or in response to the second time difference not meeting the preset requirements, using a battery resting temperature strategy to perform SOC correction.

[0055] Optionally, the second time difference requirement mainly refers to the power-on time being after the power-off time. That is, if the T-BOX time is valid and the power-on time is after the power-off time, the battery resting time strategy is used to trigger SOC-OCV correction. If the T-BOX time is valid and the power-on time is before the power-off time, the battery resting temperature strategy is used to trigger SOC-OCV correction.

[0056] Generally, when using the battery rest time strategy to trigger SOC-OCV correction, the battery rest time must be greater than 2 hours to trigger SOC-OCV correction, that is, the time difference between power-on and power-off times must be greater than 2 hours.

[0057] Step 132: In response to the power-on time calibration failure, the SOC correction is performed using the battery resting temperature strategy.

[0058] Among them, the failure of power-on time calibration mainly refers to the invalid T-BOX time.

[0059] For battery resting temperature strategies, such as Figure 4 As shown, Figure 4 yes Figure 3 A flowchart of an embodiment of step 131 is shown. Step 131 may specifically include:

[0060] Step 1311: Obtain the power-on temperature value and the power-off temperature value; wherein, the power-on temperature value is the battery temperature when the battery management system is powered on for the current time, and the power-off temperature value is the battery temperature when the battery management system was powered off for the previous time.

[0061] The methods for obtaining the power-on temperature value and the power-off temperature value can be similar to those for obtaining the power-on time and the power-off time.

[0062] Specifically, during normal operation after the battery management system is powered on, the battery temperature value is acquired at regular intervals as the power-off temperature value. When the battery management system is powered off and then powered on again, the battery temperature value is acquired as the power-on temperature value.

[0063] Step 1312: Determine the temperature difference between the power-on temperature and the power-off temperature.

[0064] Step 1313: In response to the temperature difference being greater than the set temperature threshold, the SOC is corrected using the battery resting temperature strategy.

[0065] The temperature threshold can be set according to needs. Generally, if the maximum power-on temperature is below 25℃, the setting value is 5℃; otherwise, the setting value is 3℃.

[0066] Specifically, when the maximum power-on temperature is less than 25°C and the temperature difference between the power-on temperature and the power-off temperature is greater than 5°C, the SOC-OCV correction is triggered; or when the maximum power-on temperature is greater than 25°C and the temperature difference between the power-on temperature and the power-off temperature is greater than 3°C, the SOC-OCV correction is triggered.

[0067] The SOC correction method for the battery management system provided in this embodiment includes: acquiring the power-on time and T-BOX time; wherein, the power-on time is the time of the real-time clock module when the battery management system is powered on, and the T-BOX time is the time of the T-BOX system; calibrating the power-on time based on the T-BOX time; and determining the SOC correction trigger strategy based on the calibration result of the power-on time. By using the T-BOX time to calibrate the RTC time to select the corresponding SOC correction trigger strategy, on the one hand, the RTC time can be calibrated even when the RTC is not powered, and even without providing a separate auxiliary power supply to the RTC; on the other hand, the SOC correction triggering method can be determined based on the time calibration results, avoiding the problem of SOC correction not triggering in certain situations or triggering continuously.

[0068] See Figure 5 , Figure 5 This is a schematic diagram of an embodiment of the battery management system provided in this application. The battery management system 500 includes a processor 501 and a memory 502. The memory 502 is used to store program data, and the processor 501 is used to execute: acquiring the power-on time and T-BOX time; wherein, the power-on time is the time of the real-time clock module when the battery management system is powered on for the current time, and the T-BOX time is the time of the T-BOX system; calibrating the power-on time according to the T-BOX time; and determining the SOC correction strategy according to the calibration result of the power-on time.

[0069] Alternatively, in one embodiment, the battery management system 500 is applied to an electric vehicle.

[0070] See Figure 6 , Figure 6This is a schematic diagram of an embodiment of the computer-readable storage medium provided in this application. The computer-readable storage medium 600 stores program data 601. When the program data 601 is executed by the processor, it is used to: acquire the power-on time and T-BOX time; wherein, the power-on time is the time of the real-time clock module of the battery management system when it is powered on, and the T-BOX time is the time of the T-BOX system; calibrate the power-on time according to the T-BOX time; and determine the SOC correction strategy according to the calibration result of the power-on time.

[0071] In the several embodiments provided in this application, it should be understood that the disclosed methods and devices can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed.

[0072] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0073] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0074] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural changes made based on the description and drawings of this application, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for adjusting the state of charge (SOC) of a battery management system, characterized in that, The method includes: acquiring power-on time and T-BOX time; wherein, the power-on time is the time of the real-time clock module when the battery management system is powered on for the current time, and the T-BOX time is the time of the T-BOX system; The power-on time is calibrated based on the T-BOX time; Based on the calibration result of the power-on time, a SOC correction triggering strategy is determined, including: in response to the successful calibration of the power-on time, determining a second time difference between the power-on time and the power-off time, and determining the SOC correction triggering strategy based on the second time difference; wherein, the power-off time is the time of the previous power-off of the battery management system; in response to the failure of the power-on time calibration, a battery resting temperature strategy is adopted for SOC correction.

2. The method according to claim 1, characterized in that, The calibration of the power-on time based on the T-BOX time includes: Determine the first time difference between the T-BOX time and the power-on time; In response to the first time difference being greater than a set time threshold, the power-on time is calibrated to the T-BOX time.

3. The method according to claim 1 or 2, characterized in that, Before calibrating the power-on time based on the T-BOX time, the method further includes: determining whether the T-BOX time is valid; In response to the T-BOX time being valid, the step of calibrating the power-on time based on the T-BOX time is performed.

4. The method according to claim 1, characterized in that, The method further includes: Based on a preset time interval, the time of the real-time clock module is obtained and stored as the power-off time.

5. The method according to claim 4, characterized in that, The method further includes: In response to the power-down mode of the battery management system being low-voltage power-down, the time of the real-time clock module at the time of power-down is obtained and stored as the power-down time.

6. The method according to claim 1, characterized in that, The step of determining the SOC correction triggering strategy based on the second time difference includes: In response to the second time difference meeting the preset requirements, a battery resting time strategy is used for SOC correction; or In response to the second time difference not meeting the preset requirement, a battery resting temperature strategy is adopted for SOC correction.

7. The method according to claim 1 or 6, characterized in that, The method of using battery resting temperature strategy for SOC correction includes: Obtain the power-on temperature value and the power-off temperature value; wherein, the power-on temperature value is the battery temperature when the battery management system is powered on for the current time, and the power-off temperature value is the battery temperature when the battery management system was powered off for the previous time; Determine the temperature difference between the power-on temperature value and the power-off temperature value; In response to the temperature difference exceeding a set temperature threshold, a battery resting temperature strategy is employed for SOC correction.

8. A battery management system, characterized in that, The battery management system includes a processor and a memory, the memory being used to store program data, and the processor being used to execute the program data to implement the method as described in any one of claims 1-7.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores program data, which, when executed by a processor, is used to implement the method as described in any one of claims 1-7.

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