Battery management system, electric vehicle, state of charge display method, and electronic device

Abstract

The embodiment of the application provides a battery management system, an electric vehicle, a state of charge display method and an electronic device, relates to the technical field of battery management, and the battery management system is configured to: in response to monitoring that the voltage of a battery reaches a voltage protection threshold in a fast charging stage of the battery, obtaining a real-time SOC of the battery; finding a charging rate of a current SOC interval corresponding to the real-time SOC in a preset rate table to obtain a first charging rate, wherein the preset rate table at least stores charging rates corresponding to different SOC intervals; obtaining a second charging rate smaller than the first charging rate and having a difference from the first charging rate in a preset interval, and controlling a charging pile to charge at the second charging rate until the real-time SOC jumps into an adjacent SOC interval. The technical scheme of the embodiment of the application solves the technical problems of prolonging the fast charging time and reducing the user experience in the related art, and achieves the technical effects of improving the fast charging efficiency and improving the charging experience.

Description

Technical Field

[0001] This application relates to the field of battery management technology, and in particular to battery management systems, electric vehicles, state-of-charge display methods, and electronic devices. Background Technology

[0002] With the widespread use of electric vehicles and energy storage devices, lithium iron phosphate (LiFePO4) batteries are widely used in high-rate charging scenarios due to their advantages such as high safety and long cycle life.

[0003] However, in practical applications, lithium iron phosphate batteries have a wide plateau region, meaning that the terminal voltage remains relatively stable over a large range of states of charge (SOC). In fast-charging control strategies, when a voltage protection threshold is set to prevent overcharging, the voltage change in the plateau region is slow, which may trigger voltage protection prematurely at lower SOC levels. This causes the Battery Management System (BMS) to adjust the charging rate to a lower level. This premature and abnormal rate reduction prolongs fast-charging time, affects charging efficiency, and consequently degrades the user experience.

[0004] For at least one of the above-mentioned technical problems, the relevant technologies have not yet proposed an effective solution. Summary of the Invention

[0005] This application provides battery management systems, electric vehicles, state-of-charge display methods, and electronic device methods and apparatus to solve one or more of the above-mentioned technical problems.

[0006] As one aspect of this application, this application provides a battery management system, which is communicatively connected to a battery. The battery management system is configured to: in response to detecting that the battery voltage reaches a voltage protection threshold during the fast charging phase of the battery, obtain the real-time state of charge (SOC) of the battery; look up the charging rate of the current SOC interval corresponding to the real-time SOC in a preset rate table to obtain a first charging rate, wherein the preset rate table stores at least the charging rates corresponding to different SOC intervals; obtain a second charging rate that is less than the first charging rate and whose difference from the first charging rate is within a preset range, and control the charging pile to charge at the second charging rate until the real-time SOC jumps to an adjacent SOC interval.

[0007] As another aspect of the embodiments of this application, this application provides an electric vehicle, including the battery management system, battery, and display device described above; the battery management system is communicatively connected to the battery; when the electric vehicle is connected to the charging pile, the display device is used to display the calibrated SOC.

[0008] As another aspect of the embodiments of this application, this application provides a state of charge (SOC) display method, applied to the battery management system described above. The method includes: obtaining a target SOC obtained after the SOC calibration operation; and sending a display command to a display device connected to the battery management system to display the target SOC.

[0009] As another aspect of the present application, the present application provides an electronic device, including a memory, a processor, and a computer program stored in the memory, wherein the processor implements the method described above when executing the computer program.

[0010] The technical solution described in this application, when voltage protection is triggered during the fast charging phase of the battery, determines a first charging rate based on the real-time SOC calculated by the BMS and its corresponding SOC range in the rate table. Then, a second charging rate is obtained that is lower than the first charging rate and whose difference from the first charging rate is within a preset range. This second charging rate is slightly lower than the first charging rate, and is not directly adjusted to an excessively low rate in the rate table. Through this difference-limiting control, the technical problem in related technologies—where premature abnormal rate reduction due to voltage protection triggering at a low SOC—can be avoided, leading to prolonged fast charging time, reduced charging efficiency, and a degraded user experience. This achieves the technical effect of improving fast charging efficiency and enhancing the charging experience.

[0011] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application, it can be implemented according to the contents of the specification. In order to make the above and other objects, features and advantages of this application more obvious and understandable, specific embodiments of this application are given below. Attached Figure Description

[0012] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments according to this application and should not be construed as limiting the scope of this application.

[0013] Figure 1 A schematic diagram of the connection frame for the BMS, battery, display device, electric vehicle, and charging pile provided in the embodiments of this application;

[0014] Figure 2 A schematic diagram of the BMS implementation process provided in the embodiments of this application is shown;

[0015] Figure 3 This illustration shows a schematic diagram of a charging rate control provided in an embodiment of this application;

[0016] Figure 4 This illustration shows another charging rate control diagram provided in an embodiment of this application;

[0017] Figure 5 This illustration shows a schematic diagram of a charging rate update provided in an embodiment of this application;

[0018] Figure 6 This illustration shows another charging rate update diagram provided in an embodiment of this application;

[0019] Figure 7 This illustration shows another charging rate control diagram provided in an embodiment of this application;

[0020] Figures 8A-8D A schematic diagram of charging curves at different temperatures provided in the embodiments of this application is shown;

[0021] Figure 9 This illustration shows a schematic diagram of a charging rate lookup provided in an embodiment of this application;

[0022] Figure 10 This illustration shows another charging rate lookup diagram provided in an embodiment of this application;

[0023] Figure 11 A flowchart of a state of charge display method provided in an embodiment of this application is shown;

[0024] Figure 12 A structural block diagram of a state of charge display device provided in an embodiment of this application is shown;

[0025] Figure 13 A structural block diagram of the controller used to implement the embodiments of this application is shown. Detailed Implementation

[0026] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the concept or scope of this application. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0027] To facilitate understanding of the technical solutions of the embodiments of this application, the relevant technologies of the embodiments of this application are described below. The following relevant technologies are optional solutions and can be combined with the technical solutions of the embodiments of this application in any way, and all of them fall within the protection scope of the embodiments of this application.

[0028] The technical solution of this application and how it solves the aforementioned technical problems are described in detail below with specific embodiments. The listed specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0029] Figure 1 This diagram illustrates the connection framework of a BMS, battery, display device, electric vehicle, and charging pile provided in this embodiment. The BMS, battery, and display device are typically integrated hardware within the electric vehicle, belonging to its inherent functional modules. The charging pile is an external, independent charging device that only interacts with the electric vehicle for power and data exchange during charging. During charging, the BMS not only collects, monitors, and protects the battery's operating status in real time, but also proactively sends a matching charging rate request to the charging pile based on the battery's remaining charge, temperature, health status, and current charging needs. After receiving and parsing the charging rate command from the BMS, the charging pile adaptively adjusts its output voltage and current to match the requested target charging rate, ensuring stable operation under optimal battery charging conditions. Simultaneously, the BMS continuously pushes real-time battery parameters, dynamic charging rate, overall charging status, and fault warning information to the display device, providing a visual representation of the vehicle's charging status and realizing a complete collaborative working logic for battery safety management, adaptive charging rate, and status visualization.

[0030] This application embodiment optimizes the charging rate control mechanism of the BMS described above, which will be explained in detail below.

[0031] like Figure 2 As shown, the BMS can be configured to: in response to detecting that the battery voltage reaches the voltage protection threshold during the fast charging phase of the battery, obtain the real-time state of charge (SOC) of the battery; look up the charging rate of the current SOC interval corresponding to the real-time SOC in a preset rate table to obtain a first charging rate, wherein the preset rate table stores at least the charging rates corresponding to different SOC intervals; obtain a second charging rate that is less than the first charging rate and whose difference from the first charging rate is within a preset range, and control the charging pile to charge at the second charging rate until the real-time SOC jumps to an adjacent SOC interval.

[0032] Optionally, in this embodiment, the voltage protection threshold can be a fixed value, such as 3.6V, or it can be the calibration voltage at 99% SOC. The calibration voltage can be determined by setting different temperature ranges (e.g., room temperature, high temperature, low temperature, ultra-low temperature, etc.) and different initial SOCs (e.g., 10% SOC, 30% SOC, 50% SOC, etc.) and conducting fast charging tests.

[0033] The aforementioned BMS can obtain the real-time SOC of the battery using the ampere-hour integration method, the open-circuit voltage method, or a hybrid algorithm combining both. During charging or discharging, the BMS monitors the battery's charging and discharging current in real time and calculates the SOC value by integrating the capacity parameters. When the resting conditions are met, the BMS will also measure the battery's open-circuit voltage and correct for SOC drift errors based on a preset calibration curve. Some systems will also use Kalman filtering, neural networks, and other models combined with voltage, current, and temperature data to estimate the SOC, thereby improving the accuracy of SOC calculations under high-rate charging, low-temperature environments, and battery aging conditions.

[0034] The aforementioned preset rate table is a charging rate grading table based on the battery's safe operating conditions. This rate table is related not only to the SOC range but also to battery temperature conditions. Specifically, battery temperature is a crucial factor affecting the charging rate. In low-temperature environments, the battery's chemical reaction rate decreases and internal resistance increases, requiring a reduction in the charging rate for the corresponding SOC range. In high-temperature environments, the battery may overheat, necessitating a limit on the charging rate to prevent further temperature increases and battery performance degradation. Therefore, the aforementioned preset rate table corresponds to different charging rates in different temperature ranges. For example, the step rates are generally lowered in the low-temperature range, higher values ​​are used in the optimal operating range at medium temperatures, and the step rates are also appropriately lowered in the high-temperature range to balance charging efficiency and safety. Through the joint control of temperature and SOC, the charging rate can be dynamically adjusted, improving the safety and consistency of the fast charging process.

[0035] When the aforementioned BMS triggers voltage protection during the battery fast charging phase, it determines a first charging rate based on the calculated real-time SOC range within the rate table. Then, it obtains a second charging rate that is lower than the first charging rate and whose difference from the first charging rate falls within a preset range. This second charging rate is slightly lower than the first charging rate, rather than being directly adjusted to an excessively low rate in the rate table. This difference-limiting control avoids the technical problems in related technologies where premature abnormal rate reduction due to voltage protection triggering at a low SOC leads to prolonged fast charging time, reduced charging efficiency, and a degraded user experience. This achieves the technical effect of improving fast charging efficiency and enhancing the charging experience.

[0036] In one possible implementation, obtaining a second charging rate that is less than the first charging rate and whose difference from the first charging rate is within a preset range can be achieved as follows: based on the preset rate table, sequentially search for charging rates less than the first charging rate, and determine the charging rate corresponding to the Mth item, wherein the difference between the charging rate corresponding to the Mth item and the first charging rate is within the aforementioned preset range, and M is the cumulative number of times the battery voltage has reached the voltage protection threshold, M being greater than or equal to 1; set the charging rate corresponding to the Mth item as the second charging rate.

[0037] That is, when the first voltage protection is triggered, based on the first charging rate corresponding to the current SOC range, the next smaller charging rate less than the first charging rate is found as the second charging rate. If the second voltage protection is triggered, based on the first charging rate corresponding to the current SOC range, the next smaller charging rate less than the first charging rate is found as the second charging rate, and so on, until M reaches the preset threshold.

[0038] For example, such as Figure 3 The charging rates corresponding to the different SOC ranges shown are as follows: If 3.6V (or the voltage corresponding to 99% SOC) is triggered before charging to 40% SOC, the rate will jump from 0.45C to the next smaller rate of 0.42C, and then request 0.42C charging to 40% SOC; If 3.6V (or the voltage corresponding to 99% SOC) is triggered before charging to 70% SOC, the rate will jump from 0.25C to 0.18C, and then from 0.18C to the next smaller rate of 0.16C, and then request 0.16C charging to 70% SOC.

[0039] The aforementioned stepped charging rate adjustment scheme avoids the problem of directly reducing the rate to an excessively low value in the preset rate table after triggering voltage protection at low SOC, as is common in related technologies. This reduces the technical issues of prolonged fast charging time and decreased charging efficiency. Simultaneously, it reduces the adverse effects of voltage fluctuations and current surges on the internal chemical reactions of the battery, enhancing the safety of the fast charging process.

[0040] In an optional implementation, obtaining a second charging rate that is less than the first charging rate and whose difference from the first charging rate is within a preset range can also be achieved as follows: calculate the product of the first charging rate and the Nth power of a preset attenuation coefficient, wherein the difference between the calculated product and the first charging rate is within the preset range, N is the cumulative number of times the battery voltage has reached the voltage protection threshold, and N is greater than or equal to 1; set the calculated product as the second charging rate.

[0041] That is, when the first voltage protection is triggered, based on the first charging rate corresponding to the current SOC range, the first charging rate is... A preset attenuation coefficient is used, and the multiplication result is taken as the second charging rate. If secondary voltage protection is triggered, the first charging rate corresponding to the current SOC range is used. Preset attenuation coefficient A preset attenuation coefficient is used, and the result of multiplication is taken as the second charging rate mentioned above. This process is repeated until N reaches a preset threshold.

[0042] Optionally, the preset attenuation coefficient can be a static value, such as 0.80, 0.90, 0.95, etc.

[0043] Taking the preset attenuation coefficient of 0.90 as an example, if Figure 4 As shown, if a 3.6V trigger (or the voltage corresponding to 99% SOC) is applied before charging to 40% SOC, the charging rate is reduced to 0.9 times the first charging rate, and then a 0.45V charge is requested. Charge at 0.90C to 40% SOC; before reaching 55%, trigger 3.6V (or the voltage corresponding to 99% SOC), then reduce the charging rate to 0.9^2 times the first charging rate, and then request 0.38. Charges at 0.9^2C to 55% SOC; before reaching 70%, a 3.6V trigger (or the voltage corresponding to 99% SOC) is activated, reducing the charging rate to 0.9^3 times the first charging rate, and then requesting 0.25. Charges to 70% SOC at 0.9^3C.

[0044] By employing the aforementioned rate attenuation strategy based on the number of voltage protection triggers, the charging rate can be smoothly reduced by a preset ratio each time voltage protection is triggered. This avoids reducing the charging rate to an excessively low level all at once, thus mitigating the risks of prolonged fast charging time and reduced charging efficiency. This embodiment uses a fixed attenuation coefficient to control rate changes, ensuring a smooth decreasing trend in the charging rate even with continuous voltage protection triggers. This maintains stable charging current and power output during fast charging, improving the user's charging experience. Simultaneously, it reduces the impact of sudden changes in current and power on the battery's internal chemical reactions and temperature rise, contributing to enhanced safety during the fast charging phase.

[0045] The aforementioned preset attenuation coefficient can also be a dynamic value. In an optional embodiment, the battery management system is further configured to: for a first type of SOC range or a first type of temperature condition, set a coefficient less than a reference attenuation coefficient as a first target attenuation coefficient, and correct the first target attenuation coefficient based on the cumulative number of times the battery voltage reaches the voltage protection threshold to obtain the preset attenuation coefficient, wherein the SOC of the first type of SOC range is greater than the preset SOC threshold, and the temperature of the first type of temperature condition is greater than the preset temperature threshold; for a second type of SOC or a second type of temperature condition, set a coefficient greater than the reference attenuation coefficient as a second target attenuation coefficient, and correct the second target attenuation coefficient based on the cumulative number of times the battery voltage reaches the voltage protection threshold to obtain the preset attenuation coefficient, wherein the SOC of the second type of SOC range is less than the preset SOC threshold, and the temperature of the second type of temperature condition is less than the preset temperature threshold.

[0046] In other words, in the high SOC range or under high temperature conditions, the preset attenuation coefficient is set to a smaller value to increase the rate reduction, while in the low SOC range or under low temperature conditions, the preset attenuation coefficient is set to a larger value to reduce the rate reduction. Simultaneously, the attenuation coefficient can be dynamically adjusted based on the number of triggers. For example, when the cumulative number of triggers has not reached a preset threshold, it is determined that the battery operating condition fluctuation frequency is low and the battery state is stable, maintaining the first or second target attenuation coefficient unchanged to prioritize charging efficiency. When the cumulative number of triggers reaches the corresponding preset threshold, it is determined that the battery operating condition has recently fluctuated frequently and the battery tolerance has decreased. Based on the first or second target attenuation coefficient, the attenuation coefficient value is gradually reduced, further increasing the rate reduction and reducing the risk of continuous high-load charging of the battery.

[0047] For the aforementioned adjacent SOC intervals, this application embodiment also proposes that the BMS can be configured to: determine all charging rates to be updated that are less than the second charging rate from the preset rate table; sort all charging rates to be updated in descending order to obtain all sorted charging rates; and use all sorted charging rates to replace the charging rates of each SOC interval after the current SOC interval in turn to obtain the updated preset rate table.

[0048] In other words, once the second charging rate of the current SOC interval is determined, the BMS retrieves charging rate values ​​lower than that rate from the preset rate table and assigns these rates in descending order to the charging rate entries of the subsequent SOC intervals, thereby achieving synchronous updates of the charging rates of the subsequent SOC intervals.

[0049] Optionally, in this embodiment, when a pre-configured full charge rate is assigned to any SOC interval that has not reached full charge, the SOC interval is automatically used as the starting node, and all subsequent SOC intervals with higher values ​​are uniformly assigned the full charge rate to achieve a unified and regular configuration of the charging rate in high SOC intervals, thus avoiding the problems of disordered and redundant high-order SOC interval rates.

[0050] For example, such as Figure 5As shown, before charging to 40% SOC, a 3.6V trigger (or the voltage corresponding to 99% SOC) is applied, then the process jumps to the next smaller charging rate of 0.42C, requesting 0.42C charging to 40% SOC. The charging rate for 40% to 45% SOC is updated to 0.40C, for 45% to 50% SOC to 0.38C, and for 50% to 55% SOC to 0.32C. The charging rate for 55% to 60% SOC is updated to 0.30C, and for 60% to 65% SOC to 0.25C. Before charging to 70% SOC, a 3.6V trigger (or the voltage corresponding to 99% SOC) is activated, and the charging rate jumps to 0.16C. The charging rate for 70% to 75% SOC is updated to 0.12C, for 75% to 80% SOC to 0.11C, for 80% to 85% SOC to 0.08C, for 85% to 90% SOC to 0.08C, for 90% to 95% SOC to 0.08C, and for 95% to 100% SOC to 0.08C.

[0051] The above optional implementation methods ensure that as the SOC increases, the charging rate gradually decreases in a step-by-step manner, achieving a smooth transition and safe control of the charging process.

[0052] In an optional implementation, the BMS can also be configured to: for any first target SOC interval after the current SOC interval, calculate the product of the charging rate corresponding to the first target SOC interval and the Nth power of the preset attenuation coefficient; and set the calculated product as the charging rate of the first target SOC interval.

[0053] It is understandable that after determining the second charging rate of the current SOC range, for any target SOC range after this SOC range, the original charging rate corresponding to the target SOC range is obtained, and the charging rate is multiplied by the Nth power of the preset attenuation coefficient. The calculated product is then set as the new charging rate of the target SOC range.

[0054] For example, such as Figure 6 As shown, before charging to 40% SOC, it triggers at 3.6V (or the voltage corresponding to 99% SOC), and then jumps to the next smaller rate of 0.45. 0.9C, request 0.45 The charging rate from 0.9C to 40% SOC, and from 40% SOC to 45% SOC, has been updated to 0.42. The charging rate corresponding to 0.9C, from 45% SOC to 50% SOC, has been updated to 0.40. At 0.9C, before charging to 55% SOC, it triggers at 3.6V (or the voltage corresponding to 99% SOC), then jumps to 0.38V. The charging rate corresponding to the 55% SOC to 60% SOC range has been updated to 0.32. The charging rate corresponding to 60% SOC to 65% SOC has been updated to 0.3. 0.9^2C. Before charging to 70% SOC, it triggers at 3.6V (or the voltage corresponding to 99% SOC), then jumps to 0.25. The charging rate corresponding to 70% SOC to 75% SOC has been updated to 0.18 at 0.9^3C. The charging rate corresponding to 75% to 80% SOC at 0.9^3C has been updated to 0.18. The charging rate corresponding to 80% to 85% SOC has been updated to 0.16 at 0.9^3C. The charging rate corresponding to 85% to 90% SOC at 0.9^3C has been updated to 0.12. The charging rate corresponding to 90% SOC to 95% SOC has been updated to 0.11 at 0.9^3C. At 0.9^3C, the charging rate corresponding to 95% SOC to 100% SOC has been updated to 0.08. 0.9^3C.

[0055] Through the above optional implementation methods, when the charging rate decreases in the current SOC range, the charging rate of each subsequent SOC range is dynamically adjusted according to a uniform decay law, thereby avoiding sudden changes in the rate between each SOC range, ensuring the smoothness and safety of the fast charging process, while also taking into account charging efficiency and battery life.

[0056] Considering the potential calculation deviation of the SOC of lithium iron phosphate batteries, the embodiments of this application do not completely rely on SOC to control the charging process, and voltage jumps are added. In an optional embodiment, the BMS can also be configured to: divide the SOC interval of the target charging stage into multiple SOC intervals, wherein the target charging stage is the charging stage that the battery enters after completing the fast charging stage, and the difference between the two endpoints of each SOC interval is less than the difference between the two endpoints of the SOC interval of the fast charging stage; calibrate the voltage value of each SOC interval; and determine the charging rate based on the voltage value of each SOC interval.

[0057] Optionally, in this embodiment, a dual-condition adaptive switching strategy based on SOC and voltage can also be adopted. The charging process does not solely rely on the SOC value for rate switching; instead, it monitors the battery's real-time SOC and voltage, using both as dual judgment conditions. The control logic triggers rate switching when either condition is met first. That is, when the battery's real-time SOC reaches the target SOC range or the battery's real-time voltage reaches the target rated voltage range, the charging rate switches to the charging rate corresponding to the target SOC range or the target rated voltage range.

[0058] Optionally, in this embodiment, the target charging stage can be determined based on the charging rate corresponding to a SOC greater than or equal to 90% or less than or equal to 90%. The multiple SOC ranges can include: 90% SOC to 93% SOC range, 93% SOC to 95% SOC range, 95% SOC to 97% SOC range, 97% SOC to 99% SOC range, and 99% SOC to 100% SOC range.

[0059] For example, such as Figure 7 As shown, the voltage values ​​are 3.52V for the 90% to 93% SOC range, 3.54V for the 93% to 95% SOC range, 3.57V for the 95% to 97% SOC range, 3.60V for the 97% to 99% SOC range, and 3.65V for the 99% to 100% SOC range. If the battery's real-time voltage reaches 3.53V first, the charging rate jumps to 0.08C.

[0060] In an optional implementation, the voltage values ​​corresponding to each of the above-mentioned SOC intervals include a first voltage value, a second voltage value, a third voltage value, a fourth voltage value, and a fifth voltage value that increase sequentially. The BMS is further configured to: perform an SOC calibration operation when the battery voltage reaches the first voltage value, the second voltage value, and the third voltage value, respectively; keep the value after the SOC calibration operation unchanged when the battery voltage reaches the fourth voltage value; and set the value after the SOC calibration operation to a fully charged state when the battery voltage reaches the fifth voltage value.

[0061] In other words, when the battery voltage reaches the first, second, and third voltage values ​​respectively, the BMS performs a SOC calibration operation to correct the current SOC value and reduce drift errors caused by accumulated current calculation. When the battery voltage reaches the fourth voltage value, the BMS keeps the SOC value after the third calibration unchanged to avoid frequent modifications to the SOC value due to small voltage fluctuations or measurement noise during the near-full charge stage, thereby improving the stability of the final SOC. When the battery voltage reaches the fifth voltage value, the BMS directly sets the current SOC value to the full charge state (e.g., 100%).

[0062] Through the above optional implementation, the SOC value can be corrected in advance by sequentially performing calibration operations at multiple lower voltage nodes before the SOC full charge calibration, reducing drift accumulation in the high SOC stage. Furthermore, a hold node is set before full charge determination to fix the SOC value, avoiding insufficient SOC full charge calibration time during abnormal voltage jumps in the high SOC stage, thus preventing sudden changes in the SOC value. In addition, it ensures the stability of SOC near full charge, enhancing the consistency and reliability of the display device, improving the user's charging experience, and guaranteeing the accuracy and safety of the BMS in determining the full charge state.

[0063] Because lithium iron phosphate batteries have a long plateau period, such as Figures 8A-8D As shown, the voltage exhibits a linear growth trend at least above 90%. Considering that some charging piles in the market limit the charging capacity, such as only allowing charging to 95%, this application proposes to calibrate voltages at 93%, 95%, 97%, and 99% SOC. In an optional implementation, the voltage value of each SOC range can be calibrated as follows: For any second target SOC range among multiple SOC ranges, fast charging tests are conducted under different test conditions. The battery voltage values ​​corresponding to the second target SOC range are collected under different test conditions to obtain a corresponding voltage value set. These different test conditions include different temperature ranges and different fast charging starting SOC conditions. The voltage value set is grouped according to different temperature ranges to obtain a subset of voltage values ​​corresponding to each temperature range. The maximum voltage value in the subset of voltage values ​​is selected as the peak voltage of the corresponding temperature range. The peak voltage corresponding to the highest temperature range among the different temperature ranges is selected as the calibration voltage value of the second target SOC range.

[0064] For example, the fast charging tests shown in Tables 1 to 4 below include normal temperature zone, high temperature zone, low temperature zone, and ultra-low temperature zone, and the starting SOC for fast charging includes 10% SOC, 30% SOC, 50% SOC, 70% SOC, 80% SOC, and 90% SOC.

[0065] Table 1

[0066]

[0067] Table 2

[0068]

[0069] Table 3

[0070]

[0071] Table 4

[0072]

[0073] Based on the above tests, the measured values ​​of different SOC voltage calibrations are shown in Tables 5 to 8.

[0074] Table 5

[0075]

[0076] Table 6

[0077]

[0078] Table 7

[0079]

[0080] Table 8

[0081]

[0082] Through the aforementioned optional implementation methods, multi-dimensional operating condition testing under different temperature ranges and different fast-charging starting SOCs can comprehensively cover various working scenarios in the actual fast-charging process of vehicles. This effectively eliminates voltage data deviations caused by different charging paths and different ambient temperatures, improves the universality and adaptability of the calibration voltage across all operating conditions, and solves the technical problems of low calibration accuracy and limited adaptability under single operating conditions. In addition, using the peak voltage under high-temperature operating conditions as the judgment benchmark raises the threshold for switching voltage, matches it with the actual voltage boundary at high temperatures, avoids premature step switching under high-temperature operating conditions, maximizes the retention of the final fast-charging rate, and effectively shortens the battery full-charge time.

[0083] The following example illustrates the charging rate lookup strategy of the battery management system in this application.

[0084] Example 1

[0085] like Figure 9As shown, charging starts from 20%, requesting a 0.6C rate to charge to 25%; requesting a 0.5C rate to charge to 30%; requesting a 0.48C rate to charge to 35%; requesting a 0.45C rate, before charging to 40%, a 3.6V trigger (or the voltage corresponding to 99% SOC) is activated, then it jumps to the next smaller rate of 0.42C to charge to 40%; requesting a 0.40C rate to charge to 45%; requesting a 0.38C rate to charge to 50%; requesting a 0.32C rate to charge to 55%; requesting a 0.30C rate to charge to 60%; requesting a 0.2C rate... 5C, charge to 65%; Request rate 0.18C, before charging to 70%, trigger 3.6V (or the voltage corresponding to 99% SOC), then jump to the next smaller rate 0.16C (not the rate corresponding to 80% 0.18C, because 0.18C is not the next smaller rate), charge to 70%; Request rate 0.12C, charge to 75%; Request rate 0.11C, charge to 80%; Request rate 0.10C, charge to 85%; Request rate 0.09C, charge to 90%; Request rate 0.08C (minimum rate), charge to 100%. After 90% SOC, it jumps based on whichever comes first, SOC or voltage, and simultaneously triggers the SOC calibration strategy.

[0086] Example 2

[0087] like Figure 10 As shown, charging starts from 20%, requesting a 0.6C rate to charge to 25%; requesting a 0.5C rate to charge to 30%; requesting a 0.48C rate to charge to 35%; requesting a 0.45C rate, before charging to 40%, a 3.6V trigger (or the voltage corresponding to 99% SOC) is activated, reducing the rate to 0.9 times the current rate, charging to 40%; requesting a 0.42C rate... 0.9C, charging to 45%; request rate of increase 0.40. 0.9C, charging to 50%; requesting a rate of increase of 0.38. If, at 0.9C, before charging to 55%, a 3.6V trigger (or the voltage corresponding to 99% SOC) is applied, the charging rate will be reduced to 0.9^2 times the current rate to charge to 55%; a charging rate of 0.32 is requested. 0.9^2C, charging to 60%; request rate of increase 0.3. 0.9^2C, charging to 65%; request rate of increase 0.25. If a charge rate of 0.9^2C is triggered before reaching 70% charge, and a 3.6V threshold (or the voltage corresponding to 99% SOC) is applied, the rate multiplier will be reduced to 0.9^3 times the current rate to charge to 70%. A rate multiplier of 0.18 is requested. 0.9^3C, charging to 75%; request rate of increase 0.18. 0.9^3C, charging to 80%; request rate of increase 0.16. 0.9^3C, before charging to 85%, triggers 3.6V (the voltage corresponding to 99% SOC), no further backtracking; requesting a rate multiplier of 0.12. 0.9^3C, charging to 90%; request rate of increase 0.11. 0.9^3C, charging to 95%; request rate of increase 0.10. 0.9^3C, charging to 97%; request rate of increase 0.09. 0.9^3C, charging to 99%; request rate of increase 0.08. 0.9^3C, charging to 100%; after 90% SOC, it starts to jump to whichever comes first, SOC or voltage, and simultaneously triggers the SOC calibration strategy.

[0088] This application also provides an electric vehicle, including the aforementioned battery management system, battery, and display device; the battery management system is communicatively connected to the battery; when the electric vehicle is connected to the charging pile, the display device is used to display the calibrated SOC.

[0089] This application also provides a state-of-charge display method, applied to the aforementioned battery management system, such as... Figure 11 As shown, the method includes:

[0090] S1102, Obtain the target SOC after the SOC calibration operation;

[0091] S1104, a display command is sent to the display device connected to the battery management system to display the target SOC.

[0092] Through the above steps S1102~S1104, after the battery SOC is accurately calibrated, the high-precision target SOC obtained from the calibration is acquired and displayed in real time through a display device, which effectively makes up for the technical defects of traditional battery SOC display such as large deviation, data lag and inaccurate display.

[0093] Corresponding to the application scenarios of the state of charge display method provided in this application embodiment, this application embodiment also provides a state of charge display device, such as... Figure 12 The diagram shown is a structural block diagram of a state-of-charge display device according to an embodiment of this application, comprising:

[0094] The acquisition module 1202 is used to acquire the target SOC obtained after the SOC calibration operation;

[0095] Display module 1204 is used to send display instructions to a display device connected to the battery management system to display the target SOC.

[0096] pass Figure 12 The device shown acquires the high-precision target SOC after completing the precise calibration of the battery SOC, and displays it in real time through a display device, effectively making up for the technical defects of traditional battery SOC display such as large deviation, data lag, and inaccurate display.

[0097] This application also provides an electronic device, such as... Figure 13 As shown, the electronic device 130 includes a memory 1301 and a processor 1302. The memory 1301 stores a computer program that can run on the processor 1302. When the processor 1302 executes the computer program, it implements the method described in the above embodiments. The number of memories 1301 and processors 1302 can be one or more.

[0098] The electronic device also includes:

[0099] The communication interface 1303 is used to communicate with external devices and exchange and transmit data.

[0100] If the memory 1301, processor 1302, and communication interface 1303 are implemented independently, they can be interconnected via a bus to communicate with each other. This bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. This bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 13 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0101] Optionally, in a specific implementation, if the memory 1301, processor 1302, and communication interface 1303 are integrated on a single chip, then the memory 1301, processor 1302, and communication interface 1303 can communicate with each other through an internal interface.

[0102] This application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method provided in this application.

[0103] This application also provides a chip including a processor for calling and executing instructions stored in a memory, causing a communication device with the chip installed to perform the method provided in this application.

[0104] This application also provides a chip, including: an input interface, an output interface, a processor, and a memory. The input interface, output interface, processor, and memory are connected through an internal connection path. The processor is used to execute code in the memory. When the code is executed, the processor is used to execute the method provided in the application embodiment.

[0105] It should be understood that the aforementioned processor can be a Central Processing Unit (CPU), or other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. General-purpose processors can be microprocessors or any conventional processor. It is worth noting that the processor can be a processor supporting Advanced Reduced Instruction Set Machines (ARM) architecture.

[0106] Further, optionally, the aforementioned memory may include read-only memory and random access memory. The memory may be volatile memory or non-volatile memory, or may include both. Non-volatile memory may include read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory may include random access memory (RAM), which serves as an external cache. By way of example, but not limitation, many forms of RAM are available. Examples include Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), Synchronous DRAM (SDRAM), Double Data Rate SDRAM (DDR SDRAM), Enhanced Synchronous DRAM (ESDRAM), Sync Link DRAM (SLDRAM), and Direct Rambus RAM (DR RAM).

[0107] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. A computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions according to this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another.

[0108] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples.

[0109] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0110] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing a particular logical function or process. Furthermore, the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functionality involved.

[0111] The logic and / or steps described in the flowchart or otherwise herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus or device (such as a computer-based system, a processor-included system or other system that can fetch and execute instructions from, an instruction execution system, apparatus or device).

[0112] It should be understood that various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. All or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware, the program being stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiments.

[0113] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium. This storage medium can be a read-only memory, a disk, or an optical disk, etc.

[0114] The above description is merely an exemplary embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various variations or substitutions within the technical scope described in this application, and these should all be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A battery management system, characterized in that, The battery management system is communicatively connected to the battery, and the battery management system is configured to: In response to the detection that the battery voltage reaches the voltage protection threshold during the fast charging phase of the battery, the real-time SOC of the battery is obtained; The charging rate of the current SOC range corresponding to the real-time SOC is found in the preset rate table to obtain the first charging rate. The preset rate table stores at least the charging rates corresponding to different SOC ranges. Obtain a second charging rate that is less than the first charging rate and whose difference from the first charging rate is within a preset range, and control the charging pile to charge at the second charging rate until the real-time SOC jumps to an adjacent SOC range.

2. The battery management system according to claim 1, characterized in that, The step of obtaining a second charging rate that is less than the first charging rate and whose difference from the first charging rate is within a preset range includes: Based on the preset rate table, sequentially search for charging rates less than the first charging rate, and determine the charging rate corresponding to the Mth item. The difference between the charging rate corresponding to the Mth item and the first charging rate is within the preset range, and M is the cumulative number of times the battery voltage has reached the voltage protection threshold, M is greater than or equal to 1. Set the charging rate corresponding to the Mth item to the second charging rate.

3. The battery management system according to claim 2, characterized in that, The battery management system is also configured to: Determine all charging rates to be updated that are less than the second charging rate from the preset rate table; Sort all the charging rates to be updated in descending order to obtain all sorted charging rates; The charging rates of each subsequent SOC interval are replaced sequentially using all sorted charging rates to obtain an updated preset rate table.

4. The battery management system according to claim 1, wherein obtaining a second charging rate that is less than the first charging rate and whose difference from the first charging rate is within a preset range comprises: Calculate the product of the first charging rate and the Nth power of the preset attenuation coefficient, wherein the difference between the calculated product and the first charging rate is within the preset range, and N is the cumulative number of times the battery voltage has reached the voltage protection threshold, and N is greater than or equal to 1. Set the calculated product as the second charging rate.

5. The battery management system according to claim 4, characterized in that, The battery management system is also configured to: For the first type of SOC range or the first type of temperature condition, the coefficient that is less than the reference attenuation coefficient is set as the first target attenuation coefficient, and the first target attenuation coefficient is corrected based on the cumulative number of times the battery voltage reaches the voltage protection threshold to obtain the preset attenuation coefficient, wherein the SOC of the first type of SOC range is greater than the preset SOC threshold, and the temperature of the first type of temperature condition is greater than the preset temperature threshold. For the second type of SOC or the second type of temperature condition, a coefficient greater than the reference attenuation coefficient is set as the second target attenuation coefficient, and the second target attenuation coefficient is corrected based on the cumulative number of times the battery voltage reaches the voltage protection threshold to obtain the preset attenuation coefficient, wherein the SOC in the second type of SOC range is less than the preset SOC threshold, and the temperature of the second type of temperature condition is less than the preset temperature threshold.

6. The battery management system according to claim 4, characterized in that, The battery management system is also configured to: For any first target SOC interval after the current SOC interval, calculate the product of the charging rate corresponding to the first target SOC interval and the Nth power of the preset attenuation coefficient. Set the calculated product as the charging rate of the first target SOC range.

7. The battery management system according to claim 1, characterized in that, The battery management system is also configured to: The SOC range of the target charging stage is divided into multiple SOC ranges. The target charging stage is the charging stage that the battery enters after completing the fast charging stage. The difference between the two endpoints of each SOC range in the multiple SOC ranges is smaller than the difference between the two endpoints of the SOC range of the fast charging stage. Calibrate the voltage values ​​for each SOC range; The charging rate is determined based on the voltage value of each SOC range.

8. The battery management system according to claim 7, characterized in that, The voltage values ​​for each SOC range include a first voltage value, a second voltage value, a third voltage value, a fourth voltage value, and a fifth voltage value that increase sequentially. The battery management system is further configured to: When the battery voltage reaches the first voltage value, the second voltage value, and the third voltage value respectively, a SOC calibration operation is performed; When the battery voltage reaches the fourth voltage value, the value after the SOC calibration operation remains unchanged; When the battery voltage reaches the fifth voltage value, the value after the SOC calibration operation is set to the full charge state.

9. The battery management system according to claim 7, characterized in that, The calibration of the voltage values ​​for each SOC range includes: For any second target SOC interval among the multiple SOC intervals, fast charging tests are performed under different test conditions. The battery voltage values ​​corresponding to the second target SOC interval are collected under different test conditions to obtain the corresponding voltage value set. The different test conditions include different temperature ranges and different fast charging start SOC conditions. The voltage value set is grouped according to different temperature ranges to obtain a subset of voltage values ​​corresponding to each temperature range; The maximum voltage value in the subset of voltage values ​​is selected as the peak voltage for the corresponding temperature range; The peak voltage corresponding to the highest temperature range among the different temperature ranges is selected as the calibration voltage value of the second target SOC range.

10. An electric vehicle, characterized in that, Includes the battery management system, battery, and display device as described in any one of claims 1 to 9; The battery management system is communicatively connected to the battery; When the electric vehicle is connected to the charging station, the display device is used to display the calibrated SOC.

11. A method for displaying state of charge, characterized in that, The battery management system according to any one of claims 1 to 9 comprises: Obtain the target SOC after the SOC calibration operation; A display command is sent to a display device connected to the battery management system to display the target SOC.

12. An electronic device comprising a memory, a processor, and a computer program stored in the memory, wherein the processor, when executing the computer program, implements the method of claim 11.

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