Low-temperature energy-saving charging method, system, and medium based on lithium plating start and end points

Abstract

This invention relates to the field of battery charging control technology, and particularly to a low-temperature energy-saving charging method, system, and medium based on lithium plating start and end points. The method includes: performing segmented charging tests on a ternary lithium battery under preset low-temperature charging conditions to obtain impedance characteristic parameters; determining the lithium plating start point and lithium plating end point based on the differences in impedance characteristic parameters with changes in state of charge; establishing a correspondence between charging conditions and lithium plating boundary parameters; after connecting to a charging device, acquiring the current temperature, current voltage, current state of charge, and charging rate; matching the lithium plating start and end points corresponding to the current conditions; switching to constant voltage charging when the lithium plating start point is reached, and exiting and resuming the original charging mode when the lithium plating end point is reached. This invention effectively solves the problem that existing low-temperature charging methods for ternary lithium batteries struggle to simultaneously achieve safe lithium plating control and energy-efficient charging.

Description

Technical Field

[0001] This invention relates to the field of battery charging control technology, and in particular to a low-temperature energy-saving charging method, system, and medium based on the start and end points of lithium plating. Background Technology

[0002] Ternary lithium batteries are widely used in new energy vehicles, electric bicycles, and energy storage systems due to their high energy density and good range. During charging, the current, voltage, and state of charge (SOC) of ternary lithium batteries require control to ensure they operate within safe limits. Especially at low temperatures, the battery's internal ion transport capacity decreases, electrode reaction kinetics weaken, polarization intensifies, and lithium metal deposition (lithium plating) easily occurs at the negative electrode. Lithium plating leads to capacity decay, reduced lifespan, and in severe cases, may increase the risk of internal short circuits and thermal runaway. Therefore, low-temperature charging safety control is a crucial issue in the management of ternary lithium batteries.

[0003] Existing low-temperature charging technologies typically employ thermal management heating, self-heating, or limiting charging current and state of charge to mitigate lithium plating risks. Some technologies also identify lithium plating boundaries and adjust charging parameters through electrochemical detection or battery state monitoring. While these methods improve low-temperature charging safety, heating methods incur additional energy consumption, conservative current limiting reduces charging efficiency, and existing lithium plating boundary identification focuses primarily on the risk of lithium plating initiation, failing to fully utilize the state change characteristics between the initiation and termination points of lithium plating. This makes it difficult for charging strategies to accurately avoid the lithium plating risk zone. Therefore, existing low-temperature charging technologies for ternary lithium batteries still face the challenge of balancing lithium plating safety control with energy-efficient charging.

[0004] The information disclosed in this background section is intended only to enhance the understanding of the general background of this disclosure and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] This invention provides a low-temperature energy-saving charging method, system, and medium based on the lithium plating start and end points, which can effectively solve the problems in the background art.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A low-temperature energy-saving charging method based on the lithium plating start and end points, the method comprising: A segmented charging test was conducted on a ternary lithium battery under a preset low-temperature charging condition, and impedance characteristic parameters characterizing the lithium plating state change of the ternary lithium battery were obtained during the segmented charging test. Based on the difference in impedance characteristic parameters with state of charge, the lithium plating start point and lithium plating termination point of the ternary lithium battery under the preset low temperature charging condition are determined. Based on the lithium plating start point and lithium plating end point determined under different preset low-temperature charging conditions, a correspondence between charging conditions and lithium plating boundary parameters is established. After the ternary lithium battery is connected to the charging device, the current temperature, current voltage, current state of charge of the ternary lithium battery and the charging rate corresponding to the charging device are obtained. Based on the current temperature and the charging rate, determine the lithium plating start point and the lithium plating end point corresponding to the current charging condition in the correspondence relationship; When the current voltage or the current state of charge reaches the lithium plating start point, the charging mode of the ternary lithium battery is switched to constant voltage charging at the voltage corresponding to the lithium plating start point. When the current state of charge reaches the state of charge corresponding to the lithium plating termination point, the ternary lithium battery exits the constant voltage charging and resumes the original charging mode.

[0007] Furthermore, segmented charging tests were conducted, including: The ternary lithium battery is placed in a low-temperature environment under the preset low-temperature charging condition. The ternary lithium battery is charged at a constant current rate under the preset low-temperature charging condition until the terminal voltage of the ternary lithium battery reaches the charging cutoff voltage. After the terminal voltage reaches the charging cutoff voltage, the ternary lithium battery is charged under constant voltage until the charging current drops to the preset cutoff current. During the constant current charging and constant voltage charging processes, charging is stopped at each fixed state of charge interval, and the electrochemical impedance spectroscopy is tested at a preset relaxation time after charging is stopped.

[0008] Furthermore, the segmented charging test also includes: The charging cutoff voltage is determined based on the material system and rated parameters of the ternary lithium battery. The preset cutoff current is determined based on the capacity parameters and charging safety requirements of the ternary lithium battery; The preset state of charge interval is determined based on the state of charge change characteristics of the ternary lithium battery during low-temperature charging. The test frequency range of the electrochemical impedance spectrum is determined based on the impedance response characteristics of the ternary lithium battery, and the test frequency range covers the mid-frequency charge transfer impedance and the low-frequency diffusion impedance.

[0009] Further, obtaining the impedance characteristic parameters includes: At least two different preset relaxation times are set, and the electrochemical impedance spectra under different preset relaxation time conditions are obtained respectively; The junction impedance point between the mid-frequency charge transfer semicircular arc and the low-frequency diffusion region is determined from the Nyquist plot of the electrochemical impedance spectrum. The real part of the junction impedance point is taken as the impedance characteristic parameter, and the impedance characteristic parameter is defined as the resistance Rd at the mid-to-low frequency switching point; Plot the curves of the resistance Rd at the low-frequency switching point as a function of the state of charge under different preset relaxation time conditions.

[0010] Further, determining the lithium plating start point and the lithium plating end point includes: When the difference between the resistance Rd at the mid-to-low frequency switching point under different preset relaxation time conditions is within a preset difference range, it is determined that the ternary lithium battery has not undergone lithium plating. When the resistance Rd at the mid-to-low frequency switching point under the first preset relaxation time condition is less than the resistance Rd at the mid-to-low frequency switching point under the second preset relaxation time condition and exceeds the preset difference range, it is determined that the ternary lithium battery has undergone lithium plating, wherein the second preset relaxation time is greater than the first preset relaxation time. The state of charge at which the lithium plating state changes from a state without lithium plating to a state with lithium plating is defined as the lithium plating initiation state of charge, and the voltage at the same moment is defined as the lithium plating initiation voltage. The lithium plating initiation point is constituted by the lithium plating initiation state and the lithium plating initiation voltage; The state of charge corresponding to the transition from the lithium plating state to the non-lithiation state is defined as the lithium plating termination state of charge, and the voltage at the same moment is defined as the lithium plating termination voltage. The lithium plating termination point is constituted by the lithium plating termination state and the lithium plating termination voltage.

[0011] Furthermore, the correspondence between charging conditions and lithium plating boundary parameters is established, including: The segmented charging test and the process of determining the lithium plating start point and the lithium plating end point are repeatedly performed under different low temperatures and different typical charging rates to obtain the lithium plating start point and the lithium plating end point under different preset low temperature charging conditions. Based on the lithium plating initiation points corresponding to different low-temperature temperatures under the same typical charging rate, determine the lithium plating initiation temperature corresponding to the typical charging rate; The lithium plating initiation temperature, the lithium plating initiation point, and the lithium plating termination point are established as a corresponding relationship according to the typical charging rate and the low temperature. Based on experimental data from multiple ternary lithium batteries in the same batch, a safety margin is set for the correspondence. The battery charging rate corresponding to the maximum charging power of different types of charging devices is used as the typical charging rate. The battery charging rates corresponding to slow charging devices, fast charging devices, and ultra-fast charging devices are included in the typical charging rate.

[0012] Further, determining the charging status of the ternary lithium battery after it is connected to the charging equipment includes: When the ternary lithium battery is connected to the charging device, the current temperature, the current voltage, and the current state of charge are obtained through the battery management system; The maximum charging rate of the charging device is obtained through the battery management system, and the maximum charging rate is used as the charging rate. The lithium plating initiation temperature is found in the corresponding relationship based on the charging rate; When the current temperature is not lower than the lithium plating initiation temperature, the ternary lithium battery is charged according to the original charging method.

[0013] Furthermore, the low-temperature energy-saving charging process of the ternary lithium battery includes: When the current temperature is lower than the lithium plating initiation temperature, the corresponding lithium plating initiation point and lithium plating termination point are found in the correspondence according to the charging rate and the current temperature; Under the original charging method, the current state of charge and the current voltage are continuously collected; When the current state of charge reaches the state of charge corresponding to the lithium plating start point or the current voltage reaches the voltage corresponding to the lithium plating start point, the original charging method is switched to constant voltage charging. During the constant voltage charging process, the voltage corresponding to the lithium plating initiation point is used as the constant voltage, and the charging current is reduced as the current state of charge increases. When the current state of charge reaches the state of charge corresponding to the lithium plating termination point, the constant voltage charging will be switched back to the original charging mode. Battery heating is not activated during the low-temperature charging control process of the ternary lithium battery. The low-temperature charging control method for ternary lithium batteries is applied to the low-temperature charging optimization of vehicles or energy storage systems powered by the ternary lithium batteries.

[0014] A low-temperature energy-saving charging system based on the lithium plating start and end points, the system comprising: The segmented impedance acquisition module performs segmented charging tests on ternary lithium batteries under preset low-temperature charging conditions, and acquires impedance characteristic parameters that characterize the changes in the lithium plating state of ternary lithium batteries during the segmented charging test. The lithium plating boundary determination module determines the lithium plating start point and lithium plating termination point of the ternary lithium battery under a preset low-temperature charging condition based on the difference in impedance characteristic parameters with the state of charge. The boundary relationship establishment module establishes the correspondence between the charging conditions and the lithium plating boundary parameters based on the lithium plating start point and lithium plating end point determined under different preset low temperature charging conditions. The charging status acquisition module acquires the current temperature, current voltage, current state of charge of the ternary lithium battery and the charging rate corresponding to the charging equipment after the ternary lithium battery is connected to the charging equipment. The current boundary matching module determines the lithium plating start point and lithium plating end point corresponding to the current charging condition in the corresponding relationship based on the current temperature and charging rate. The constant voltage switching control module switches the charging mode of the ternary lithium battery to constant voltage charging based on the voltage corresponding to the lithium plating start point when the current voltage or the current state of charge reaches the lithium plating start point. The charging recovery control module, when the current state of charge reaches the state of charge corresponding to the lithium plating termination point, causes the ternary lithium battery to exit constant voltage charging and resume the original charging mode.

[0015] A computer-readable storage medium storing a computer program, the computer program including program instructions that, when executed by a processor, can implement the aforementioned low-temperature energy-saving charging method based on lithium plating start and end points.

[0016] An electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the low-temperature energy-saving charging method based on the lithium plating start and end points.

[0017] The technical solution of this invention can achieve the following technical effects: By obtaining impedance characteristic parameters of ternary lithium batteries through low-temperature segmented charging tests and calibrating the lithium plating start and end points, a correspondence between charging conditions and lithium plating boundary parameters is established. Then, during actual charging, the lithium plating boundary is matched according to the current temperature, state of charge, voltage, and charging rate. In the lithium plating risk range, constant voltage charging is switched, and the original charging mode is restored after the range is crossed. This effectively solves the problem that existing low-temperature charging strategies for ternary lithium batteries rely on heating or conservative current limiting because they cannot accurately utilize the lithium plating start and end boundaries, resulting in a difficulty in achieving both low-temperature safe charging and energy-efficient charging.

[0018] 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 and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of a low-temperature energy-saving charging method based on the start and end points of lithium plating. Figure 2 A schematic diagram of the low-frequency switching point resistance Rd versus SOC curve in the electrochemical impedance spectroscopy of a ternary lithium battery during constant current and constant voltage charging at 5% SOC intervals. Figure 3 A schematic diagram of the voltage curve of a ternary lithium battery charged with constant current and constant voltage at 5% SOC intervals. Figure labels: Rd, resistance at the low-to-medium frequency transition point; SOC, state of charge; Figure 2 The orange curve represents the resistance change at the mid-to-low frequency switching point after 0.5 hours of relaxation, while the blue curve represents the resistance change at the mid-to-low frequency switching point after 1 hour of relaxation. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0023] Example 1; like Figure 1 As shown, this application provides a low-temperature energy-saving charging method based on the lithium plating start and end points, the method including: S10: Perform segmented charging tests on ternary lithium batteries under preset low-temperature charging conditions, and obtain impedance characteristic parameters characterizing the lithium plating state changes of ternary lithium batteries during the segmented charging test. S20: Based on the difference in impedance characteristic parameters with the state of charge, determine the lithium plating start point and lithium plating termination point of the ternary lithium battery under the preset low temperature charging condition. S30: Based on the lithium plating start point and lithium plating end point determined under different preset low temperature charging conditions, establish the correspondence between charging conditions and lithium plating boundary parameters. S40: After the ternary lithium battery is connected to the charging equipment, obtain the current temperature, current voltage, current state of charge of the ternary lithium battery and the charging rate corresponding to the charging equipment. S50: Based on the current temperature and charging rate, determine the lithium plating start point and lithium plating end point corresponding to the current charging condition in the corresponding relationship; S60: When the current voltage or current state of charge reaches the lithium plating start point, switch the charging mode of the ternary lithium battery to constant voltage charging at the voltage corresponding to the lithium plating start point. S70: When the current state of charge reaches the state of charge corresponding to the lithium plating termination point, the ternary lithium battery exits constant voltage charging and resumes the original charging mode.

[0024] Specifically, this embodiment provides a low-temperature charging control method for ternary lithium batteries. This method is applicable to vehicles, electric bicycles, or energy storage systems that use ternary lithium batteries as power sources or energy storage units. The method includes an offline lithium plating boundary calibration process and an online low-temperature charging control process. The offline lithium plating boundary calibration process is used to obtain the lithium plating start point and lithium plating end point of the ternary lithium battery under different low-temperature charging conditions. The online low-temperature charging control process is used to select the appropriate charging control mode according to the current operating conditions after the ternary lithium battery is actually connected to the charging equipment. In the offline lithium plating boundary calibration process, the ternary lithium battery under test is placed in a preset low temperature environment and segmented charging test is performed according to a preset charging rate. Specifically, the ternary lithium battery is first charged with constant current. When the terminal voltage of the ternary lithium battery reaches the charging cutoff voltage, it is switched to constant voltage charging. During the charging process, charging is paused at preset state of charge intervals to allow the ternary lithium battery to enter the relaxation state. Subsequently, electrochemical impedance spectroscopy tests are performed on the ternary lithium battery at different relaxation times to obtain impedance characteristic parameters that can characterize the lithium plating state changes of the ternary lithium battery. After obtaining the electrochemical impedance spectroscopy, the resistance at the low-to-mid frequency transition point was extracted as the impedance characteristic parameter, and the curve of the impedance characteristic parameter changing with the state of charge was plotted. Since the impedance characteristic parameter measured at different relaxation times is relatively small when lithium plating has not occurred, while the impedance characteristic parameter measured at a shorter relaxation time will show a significant change compared with the impedance characteristic parameter measured at a longer relaxation time when lithium plating has occurred, the difference in impedance characteristic parameter changing with the state of charge can be used to determine whether lithium plating has occurred in the ternary lithium battery. When a ternary lithium battery changes from a state without lithium plating to a state with lithium plating, the state of charge and voltage corresponding to the change position are determined as the lithium plating start point; when a ternary lithium battery changes from a state with lithium plating to a state without lithium plating, the state of charge and voltage corresponding to the change position are determined as the lithium plating end point; thus, the corresponding lithium plating start point and lithium plating end point can be obtained under a preset low-temperature charging condition. Furthermore, the above-mentioned segmented charging test and impedance characteristic parameter analysis process were repeated at different low temperatures and different charging rates to determine the lithium plating start point and lithium plating end point under different preset low temperature charging conditions. Based on the lithium plating start point and lithium plating end point under different preset low temperature charging conditions, a correspondence between charging conditions and lithium plating boundary parameters was established. The correspondence can be stored in the battery management system or the control unit that communicates with the battery management system for use when the ternary lithium battery is actually charged. During the online low-temperature charging control process, when the ternary lithium battery is connected to the charging equipment, the battery management system obtains the current temperature, current voltage, current state of charge of the ternary lithium battery and the charging rate corresponding to the charging equipment. Based on the current temperature and charging rate, it finds the lithium plating start point and lithium plating end point corresponding to the current charging condition in the correspondence. In the initial stage of charging, if there is no risk of lithium plating under the current charging conditions corresponding to the current temperature, or if the lithium plating initiation point has not been reached, the ternary lithium battery will be charged according to the original charging method. As the charging process progresses, the battery management system continuously collects the current voltage and the current state of charge, and compares the current voltage and the current state of charge with the lithium plating initiation point respectively. When the current voltage reaches the voltage corresponding to the lithium plating initiation point, or the current state of charge reaches the state of charge corresponding to the lithium plating initiation point, it is determined that the ternary lithium battery is about to enter the lithium plating risk zone, and the charging method of the ternary lithium battery is switched from the original charging method to constant voltage charging based on the voltage corresponding to the lithium plating initiation point. During constant voltage charging, the charging current of the ternary lithium battery gradually decreases as the state of charge increases, thereby reducing the risk of lithium plating on the negative electrode in low-temperature environments. The battery management system continues to monitor the current state of charge. When the current state of charge reaches the state of charge corresponding to the lithium plating termination point, it determines that the ternary lithium battery has left the lithium plating risk range and causes the ternary lithium battery to exit constant voltage charging. Then, it continues the original charging method to complete the subsequent charging process.

[0025] The technical solution of this invention obtains the impedance characteristic parameters of ternary lithium batteries through low-temperature segmented charging tests and calibrates the lithium plating start point and lithium plating end point, establishing a correspondence between charging conditions and lithium plating boundary parameters. Then, during actual charging, the lithium plating boundary is matched according to the current temperature, state of charge, voltage, and charging rate. In the lithium plating risk range, constant voltage charging is switched, and the original charging mode is restored after the range is crossed. This effectively solves the problem that existing low-temperature charging strategies for ternary lithium batteries rely on heating or conservative current limiting because it is difficult to accurately utilize the lithium plating start and end boundaries, resulting in a difficulty in achieving both low-temperature safe charging and energy-efficient charging.

[0026] Furthermore, segmented charging tests were conducted, including: Place the ternary lithium battery in a low-temperature environment under the preset low-temperature charging conditions. The ternary lithium battery is charged at a constant current rate under a preset low-temperature charging condition until the terminal voltage of the ternary lithium battery reaches the charging cutoff voltage. After the terminal voltage reaches the charging cutoff voltage, the ternary lithium battery is charged under constant voltage until the charging current drops to the preset cutoff current. During constant current charging and constant voltage charging, charging is stopped at each fixed state of charge interval, and electrochemical impedance spectroscopy is measured at a preset relaxation time after charging is stopped.

[0027] Furthermore, conducting segmented charging tests also includes: The charging cutoff voltage is determined based on the material system and rated parameters of the ternary lithium battery. The preset cutoff current is determined based on the capacity parameters and charging safety requirements of the ternary lithium battery. The preset state of charge interval is determined based on the characteristics of the state of charge change of ternary lithium batteries during low-temperature charging. The test frequency range of the electrochemical impedance spectroscopy is determined based on the impedance response characteristics of ternary lithium batteries, and the test frequency range covers the mid-frequency charge transfer impedance and the low-frequency diffusion impedance.

[0028] As a preferred embodiment of the above, the segmented charging test is used to obtain impedance change information of the ternary lithium battery during low-temperature charging. First, the ternary lithium battery is placed in a preset low-temperature environment, and the test begins after the battery temperature reaches a stable state. Then, the ternary lithium battery is charged with constant current according to the charging rate corresponding to the preset low-temperature charging condition. The charging rate can be determined according to the type of charging equipment. For example, electric bicycle charging equipment can use 0.125C or 0.2C, and new energy vehicle charging equipment can use 0.125C, 0.2C, 0.5C, 1C, 2C, or 3C. During constant current charging, the terminal voltage and state of charge are collected in real time. When the terminal voltage reaches the charging cutoff voltage, it switches to constant voltage charging and continues to collect charging current, terminal voltage, and state of charge. For ternary lithium batteries, the charging cutoff voltage can be 4.2V, and constant voltage charging can continue until the charging current drops to 0.05C. During constant current charging and constant voltage charging, charging is paused whenever the state of charge reaches a fixed interval, allowing the ternary lithium battery to enter a relaxation state. As one implementation method, segmented charging at 5% SOC intervals can be used to ensure consistent state of charge changes between different test points. During relaxation, electrochemical impedance spectroscopy (EIS) tests are performed on the ternary lithium battery after a preset relaxation time has elapsed. For example, EIS tests can be performed at 0.5h and 1h of relaxation, respectively. Through the above segmented charging, relaxation, and impedance testing, impedance data at different states of charge can be obtained, providing a data basis for subsequent determination of the lithium plating start and end points. In this embodiment, the parameters in the segmented charging test are determined based on the characteristics of the ternary lithium battery itself and the purpose of the low-temperature charging test; the charging cut-off voltage can be determined based on the ternary lithium battery material system, rated voltage platform and safety charging requirements, specifically using 4.2V, which is commonly used in ternary lithium batteries, as the charging cut-off voltage; the preset cut-off current can be determined based on the ternary lithium battery capacity parameters and constant voltage charging termination conditions, specifically using 0.05C as the judgment condition for the end of constant voltage charging. The preset state of charge interval can be determined based on the accuracy of identifying changes in the lithium plating state during low-temperature charging. Specifically, 5% SOC can be used as the state of charge interval between adjacent test points. The test frequency range of the electrochemical impedance spectroscopy can be determined based on the impedance response characteristics of the ternary lithium battery. Specifically, a test frequency range of 10kHz to 0.01Hz can be used, and this test frequency range should cover the mid-frequency charge transfer impedance and part of the low-frequency impedance, so as to facilitate the extraction of the mid-to-low frequency transition point resistance between the mid-frequency charge transfer semi-circular arc and the low-frequency diffusion region in the Nyquist plot.

[0029] Furthermore, obtaining impedance characteristic parameters includes: Set at least two different preset relaxation times and obtain electrochemical impedance spectroscopy under different preset relaxation time conditions; The junction impedance point between the mid-frequency charge transfer semicircular arc and the low-frequency diffusion region is determined from the Nyquist plot of the electrochemical impedance spectroscopy. The real part of the junction impedance point is taken as the impedance characteristic parameter, and the impedance characteristic parameter is defined as the resistance Rd at the mid-to-low frequency transition point; Plot the curves of the resistance Rd at the mid-to-low frequency switching point as a function of the state of charge under different preset relaxation time conditions.

[0030] As a preferred embodiment of the above, the impedance characteristic parameters are obtained by extracting the electrochemical impedance spectra of the ternary lithium battery at different relaxation times; during the segmented charging test, after each pause in charging, the ternary lithium battery is allowed to enter a relaxation state, and electrochemical impedance spectra are tested at at least two different relaxation times; as a specific implementation, the electrochemical impedance spectra can be tested at 0.5h and 1h relaxation times respectively to obtain impedance response data corresponding to different relaxation times under the same charge state. After obtaining the electrochemical impedance spectroscopy, the mid-frequency charge transfer semicircular arc and the low-frequency diffusion region are identified based on the Nyquist plot of the electrochemical impedance spectroscopy, and the junction impedance point between the mid-frequency charge transfer semicircular arc and the low-frequency diffusion region is determined. This junction impedance point can reflect the impedance change characteristics between the charge transfer process and the diffusion process of the ternary lithium battery under the corresponding state of charge. Furthermore, the real part of the junction impedance point in the Nyquist plot is taken as the impedance characteristic parameter, and this impedance characteristic parameter is defined as the resistance Rd at the mid-to-low frequency transition point. For each state of charge point after segmented charging, the resistance Rd at the mid-to-low frequency transition point under relaxation conditions of 0.5h and 1h can be extracted respectively. Subsequently, using the state of charge (SOC) as the abscissa and the resistance Rd at the mid-to-low frequency transition point as the ordinate, curves showing the variation of Rd with SOC under different relaxation times were plotted. As a specific implementation, curves showing the variation of Rd with SOC under relaxation times of 0.5h and 1h can be plotted on the same graph to compare the differences in impedance characteristic parameters under different relaxation times, providing a basis for subsequently determining the lithium plating initiation and termination points. Figure 2 The figure shows an example of the Rd versus SOC curves obtained by testing a ternary lithium battery at low temperature and a specific rate, based on the interval state of charge charging, after relaxation for 0.5h and 1h respectively.

[0031] Furthermore, determining the lithium plating start point and lithium plating end point includes: When the difference between the resistance Rd at the mid-to-low frequency switching point under different preset relaxation time conditions is within the preset difference range, it is determined that the ternary lithium battery has not undergone lithium plating. When the resistance Rd at the mid-to-low frequency conversion point under the first preset relaxation time condition is less than the resistance Rd at the mid-to-low frequency conversion point under the second preset relaxation time condition and exceeds the preset difference range, it is determined that lithium plating has occurred in the ternary lithium battery, wherein the second preset relaxation time is greater than the first preset relaxation time. The state of charge at which the lithium plating state changes from a state without lithium plating to a state with lithium plating is defined as the lithium plating initiation state of charge, and the voltage at the same moment is defined as the lithium plating initiation voltage. The lithium plating initiation point is determined by the lithium plating initiation state of charge and the lithium plating initiation voltage. The state of charge corresponding to the transition from the lithium plating state to the non-lithiation state is defined as the lithium plating termination state of charge, and the voltage at the same moment is defined as the lithium plating termination voltage. The lithium plating termination point is constituted by the lithium plating termination state of charge and the lithium plating termination voltage.

[0032] As a preferred embodiment of the above, the lithium plating start point and lithium plating end point are determined based on the difference in the change of the resistance Rd at the mid-to-low frequency switching point with the state of charge under different relaxation times; specifically, after completing the segmented charging and electrochemical impedance spectroscopy test, the curves of Rd with the state of charge under shorter relaxation time and longer relaxation time conditions are obtained respectively, and the two curves are compared. When the Rd values ​​under different relaxation times are basically the same under the same state of charge, it indicates that the ternary lithium battery has not undergone significant lithium plating near that state of charge. When the Rd value under a shorter relaxation time is significantly smaller than the Rd value under a longer relaxation time, it indicates that the ternary lithium battery has undergone lithium plating near that state of charge. The reason for this is that the impedance change of the battery after relaxation is small in the non-lithium-plated state, while the lithium metal stripping and re-intercalation reaction has not been fully completed in the lithium-plated state, resulting in significant differences in the impedance characteristic parameters obtained under different relaxation times. In the judgment process, the state of charge corresponding to the transition of the ternary lithium battery from a non-lithium-plated state to a lithium-plated state is determined as the lithium plating initiation state of charge, and the voltage corresponding at the same moment is determined as the lithium plating initiation voltage. The lithium plating initiation state of charge and the lithium plating initiation voltage constitute the lithium plating initiation point. The state of charge corresponding to the transition of the ternary lithium battery from a lithium-plated state to a non-lithium-plated state is determined as the lithium plating termination state of charge, and the voltage corresponding at the same moment is determined as the lithium plating termination voltage. The lithium plating termination state of charge and the lithium plating termination voltage constitute the lithium plating termination point. As a specific embodiment, it can be combined with Figure 2 and Figure 3 Provide an explanation; Figure 2 The curves of Rd versus SOC corresponding to different relaxation times of a certain ternary lithium battery under low temperature, specific rate and interval state of charge charging conditions are given; Figure 3 The voltage curves for the same charging process are given; based on Figure 2The differences in the Rd curve indicate that the ternary lithium battery did not undergo lithium plating during the low state of charge stage, but did undergo lithium plating in the intermediate state of charge range, and returned to a non-lithium-plating state after entering constant voltage charging and the current decreased; further combined with Figure 3 The voltage curves show that the lithium plating start point is 29.1% SOC, 4.18V, and the lithium plating end point is 59.4% SOC, 4.2V.

[0033] Furthermore, establishing the correspondence between charging conditions and lithium plating boundary parameters includes: The process of repeatedly performing segmented charging tests and determining the lithium plating start point and lithium plating end point under different low temperature and different typical charging rates was carried out to obtain the lithium plating start point and lithium plating end point under different preset low temperature charging conditions. Based on the lithium plating initiation point corresponding to different low temperatures under the same typical charging rate, determine the lithium plating initiation temperature corresponding to the typical charging rate. The lithium plating initiation temperature, lithium plating initiation point, and lithium plating termination point are established as corresponding relationships based on typical charging rates and low-temperature temperatures. Based on experimental data from multiple ternary lithium batteries in the same batch, a safety margin was set for the corresponding relationships; The battery charging rate corresponding to the maximum charging power of different types of charging devices is used as the typical charging rate. The battery charging rates corresponding to slow charging devices, fast charging devices, and ultra-fast charging devices are included in the typical charging rate.

[0034] As a preferred embodiment of the above, the correspondence is used to characterize the mapping relationship between different low-temperature charging conditions and lithium plating boundary parameters, so that the ternary lithium battery can quickly match the lithium plating start point and lithium plating end point under the current conditions after being actually connected to the charging equipment. Specifically, after identifying the lithium plating initiation point and lithium plating termination point under a single low temperature and a single charging rate, the low temperature and typical charging rate are changed, and the segmented charging test, electrochemical impedance spectroscopy test and lithium plating boundary identification process are repeated to obtain the lithium plating initiation state of charge, lithium plating initiation voltage, lithium plating termination state of charge and lithium plating termination voltage under multiple low temperature charging conditions. Under the same typical charging rate, the lithium plating initiation points corresponding to different low temperatures are compared to determine the lithium plating initiation temperature corresponding to that typical charging rate. The lithium plating initiation temperature indicates that under that charging rate, when the battery temperature is greater than or equal to that temperature, no lithium plating initiation point occurs; when the battery temperature is lower than that temperature, a lithium plating initiation point occurs. Subsequently, the low temperature, typical charging rate, lithium plating initiation temperature, lithium plating initiation state of charge, lithium plating initiation voltage, lithium plating termination state of charge, and lithium plating termination voltage are associated and stored to form a correspondence between charging conditions and lithium plating boundary parameters. This correspondence can be stored in the battery management system or vehicle control unit in the form of a data table, mapping model, or lookup table, and can be used to call the corresponding lithium plating boundary parameters according to the current temperature and charging rate during actual charging. As a specific implementation method, the typical charging rate can be calculated based on the maximum charging power of different charging devices. For example, 0.125C and 0.2C can be selected as typical charging rates for electric bicycle charging devices, and 0.125C, 0.2C, 0.5C, 1C, 2C, and 3C can be selected as typical charging rates for new energy vehicle charging devices. For each typical charging rate, repeated testing can be conducted at multiple low-temperature temperatures to establish the corresponding relationship of lithium plating boundary parameters covering slow charging, fast charging, and supercharging scenarios. Furthermore, to improve safety in practical applications, a safety margin can be set for the corresponding relationship based on experimental data from multiple ternary lithium batteries in the same batch. For example, the lithium plating start point can be corrected to a more conservative state of charge or voltage direction, or the lithium plating termination point can be corrected to a safer state of charge direction, so as to reduce the impact of cell consistency differences, aging state differences or test errors on the low-temperature charging control results.

[0035] Furthermore, determining the charging status of a ternary lithium battery after it is connected to a charging device includes: When a ternary lithium battery is connected to a charging device, the current temperature, current voltage, and current state of charge are obtained through the battery management system. The maximum charging rate of the charging device is obtained through the battery management system, and the maximum charging rate is used as the charging rate. Find the lithium plating initiation temperature in the corresponding relationship based on the charging rate; When the current temperature is not lower than the lithium plating initiation temperature, the ternary lithium battery is charged according to the original charging method.

[0036] As a preferred embodiment of the above, after the ternary lithium battery is connected to the charging equipment, the battery management system performs the charging condition judgment. The battery management system first collects the current temperature, current voltage and current state of charge of the ternary lithium battery. The current temperature is used to determine whether there is a risk of lithium plating in a low-temperature environment, and the current voltage and current state of charge are used for subsequent comparison with the lithium plating boundary parameters. At the same time, the battery management system obtains the maximum charging rate corresponding to the charging equipment and uses the maximum charging rate as the current charging rate. The maximum charging rate can be determined by the output capacity of the charging equipment, the rated capacity of the battery pack, or charging communication information. For example, after the vehicle is connected to the charging pile, the battery management system can calculate the corresponding charging rate based on the allowable output power of the charging pile. Subsequently, the battery management system searches for the lithium plating initiation temperature corresponding to the current charging rate in the pre-established correspondence between charging conditions and lithium plating boundary parameters. The lithium plating initiation temperature is used to distinguish whether the current charging condition has entered the low-temperature lithium plating risk range. When the current temperature is not lower than the lithium plating initiation temperature, it means that the ternary lithium battery is not likely to have a lithium plating initiation point under the current charging rate, and the battery management system controls the ternary lithium battery to be charged according to the original charging method. As one specific implementation method, after a new energy vehicle is connected to a charging pile, the battery management system obtains the current temperature, current voltage, and current state of charge of the battery, and determines the current charging rate based on the maximum output capacity of the charging pile. If the lithium plating initiation temperature corresponding to the current charging rate is already stored in the corresponding relationship, the lithium plating initiation temperature is directly called and compared with the current temperature. If the current temperature is higher than or equal to the lithium plating initiation temperature, there is no need to switch to the low-temperature energy-saving charging strategy, and the original constant current and constant voltage charging method is continued to complete the charging.

[0037] Furthermore, the low-temperature energy-saving charging process of ternary lithium batteries includes: When the current temperature is lower than the lithium plating initiation temperature, the corresponding lithium plating initiation and termination points are found in the corresponding relationship based on the charging rate and the current temperature. Under the original charging method, continuously collect the current state of charge and current voltage; When the current state of charge reaches the state of charge corresponding to the lithium plating start point or the current voltage reaches the voltage corresponding to the lithium plating start point, the original charging method will be switched to constant voltage charging. During constant voltage charging, the voltage corresponding to the lithium plating initiation point is used as the constant voltage, and the charging current is reduced as the current state of charge increases. When the current state of charge reaches the state of charge corresponding to the lithium plating termination point, the constant voltage charging will be switched back to the original charging mode. Battery heating is not activated during the low-temperature charging control process of ternary lithium batteries. The low-temperature charging control method for ternary lithium batteries is applied to the low-temperature charging optimization of vehicles or energy storage systems powered by ternary lithium batteries.

[0038] As a preferred embodiment of the above, when the ternary lithium battery is connected to the charging equipment, the battery management system first determines whether to enter the low-temperature energy-saving charging process based on the current temperature and the current charging rate; if the current temperature is lower than the lithium plating start temperature corresponding to the current charging rate, it indicates that there is a risk of lithium plating under this condition. The battery management system searches for the matching lithium plating start point and lithium plating end point in the pre-established correspondence based on the current temperature and the current charging rate. During the charging process, the battery management system continuously collects the current state of charge and current voltage of the ternary lithium battery, and compares the current state of charge and current voltage with the state of charge and voltage corresponding to the lithium plating initiation point, respectively. When the current state of charge reaches the state of charge corresponding to the lithium plating initiation point, or the current voltage reaches the voltage corresponding to the lithium plating initiation point, the battery management system determines that the ternary lithium battery is about to enter the lithium plating risk zone and switches the original charging mode to constant voltage charging. During constant voltage charging, the voltage corresponding to the lithium plating start point is used as the constant voltage for charging, so that the charging current naturally decreases as the state of charge increases, thereby reducing the risk of lithium plating on the negative electrode under low temperature conditions. The battery management system continues to monitor the current state of charge. When the current state of charge reaches the state of charge corresponding to the lithium plating termination point, it is determined that the ternary lithium battery has left the lithium plating risk range, and the ternary lithium battery is controlled to exit constant voltage charging, and then the original charging method is continued to complete the subsequent charging. In one specific implementation, under low temperature and a specific magnification condition, it can be based on Figure 2 The curve of the resistance Rd at the mid-to-low frequency switching point as a function of SOC and Figure 3 The charging voltage curve was used to determine the starting point of lithium plating as 29.1% SOC and 4.18V, and the ending point as 59.4% SOC and 4.2V. During actual charging, when the ternary lithium battery reaches 29.1% SOC or 4.18V, the charging mode is switched to constant voltage charging at 4.18V. When the state of charge reaches 59.4% SOC, constant voltage charging is stopped and the original charging mode is restored.

[0039] Example 2; Based on the same inventive concept as the low-temperature energy-saving charging method based on the lithium plating start and end points in the foregoing embodiments, the present invention also provides a low-temperature energy-saving charging system based on the lithium plating start and end points, the system comprising: The segmented impedance acquisition module performs segmented charging tests on ternary lithium batteries under preset low-temperature charging conditions, and acquires impedance characteristic parameters that characterize the changes in the lithium plating state of ternary lithium batteries during the segmented charging test. The lithium plating boundary determination module determines the lithium plating start point and lithium plating termination point of the ternary lithium battery under a preset low-temperature charging condition based on the difference in impedance characteristic parameters with the state of charge. The boundary relationship establishment module establishes the correspondence between the charging conditions and the lithium plating boundary parameters based on the lithium plating start point and lithium plating end point determined under different preset low temperature charging conditions. The charging status acquisition module acquires the current temperature, current voltage, current state of charge of the ternary lithium battery and the charging rate corresponding to the charging equipment after the ternary lithium battery is connected to the charging equipment. The current boundary matching module determines the lithium plating start point and lithium plating end point corresponding to the current charging condition in the corresponding relationship based on the current temperature and charging rate. The constant voltage switching control module switches the charging mode of the ternary lithium battery to constant voltage charging based on the voltage corresponding to the lithium plating start point when the current voltage or the current state of charge reaches the lithium plating start point. The charging recovery control module, when the current state of charge reaches the state of charge corresponding to the lithium plating termination point, causes the ternary lithium battery to exit constant voltage charging and resume the original charging mode.

[0040] The adjustment system described above in this invention can effectively realize the low-temperature energy-saving charging method based on the lithium plating start and end points, and the technical effects it can achieve are as described in the above embodiments, and will not be repeated here.

[0041] Example 3; Based on the same inventive concept as the low-temperature energy-saving charging method based on the lithium plating start and end points in the foregoing embodiments, the present invention also provides a computer-readable storage medium storing a computer program, the computer program including program instructions, which, when executed by a processor, can implement the low-temperature energy-saving charging method based on the lithium plating start and end points.

[0042] Example 4; Based on the same inventive concept as the low-temperature energy-saving charging method based on the lithium plating start and end points in the foregoing embodiments, the present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the low-temperature energy-saving charging method based on the lithium plating start and end points.

[0043] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the spirit and scope of this application. Accordingly, this specification and drawings are merely exemplary illustrations of the application as defined herein, and are to be considered as covering any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from its scope. Thus, if such modifications and modifications fall within the scope of this application and its equivalents, this application intends to include such modifications and modifications.

Claims

1. A low-temperature energy-saving charging method based on the start and end points of lithium plating, characterized in that, The method includes: A segmented charging test was conducted on a ternary lithium battery under a preset low-temperature charging condition, and impedance characteristic parameters characterizing the lithium plating state change of the ternary lithium battery were obtained during the segmented charging test. Based on the difference in impedance characteristic parameters with state of charge, the lithium plating start point and lithium plating termination point of the ternary lithium battery under the preset low temperature charging condition are determined. Based on the lithium plating start point and lithium plating end point determined under different preset low-temperature charging conditions, a correspondence between charging conditions and lithium plating boundary parameters is established. After the ternary lithium battery is connected to the charging device, the current temperature, current voltage, current state of charge of the ternary lithium battery and the charging rate corresponding to the charging device are obtained. Based on the current temperature and the charging rate, determine the lithium plating start point and the lithium plating end point corresponding to the current charging condition in the correspondence relationship; When the current voltage or the current state of charge reaches the lithium plating start point, the charging mode of the ternary lithium battery is switched to constant voltage charging at the voltage corresponding to the lithium plating start point. When the current state of charge reaches the state of charge corresponding to the lithium plating termination point, the ternary lithium battery exits the constant voltage charging and resumes the original charging mode.

2. The low-temperature energy-saving charging method based on the lithium plating start and end points according to claim 1, characterized in that, Segmented charging tests were conducted, including: The ternary lithium battery is placed in a low-temperature environment under the preset low-temperature charging condition. The ternary lithium battery is charged at a constant current rate under the preset low-temperature charging condition until the terminal voltage of the ternary lithium battery reaches the charging cutoff voltage. After the terminal voltage reaches the charging cutoff voltage, the ternary lithium battery is charged under constant voltage until the charging current drops to the preset cutoff current. During the constant current charging and constant voltage charging processes, charging is stopped at each fixed state of charge interval, and the electrochemical impedance spectroscopy is tested at a preset relaxation time after charging is stopped.

3. The low-temperature energy-saving charging method based on the lithium plating start and end points according to claim 2, characterized in that, The segmented charging test also includes: The charging cutoff voltage is determined based on the material system and rated parameters of the ternary lithium battery. The preset cutoff current is determined based on the capacity parameters and charging safety requirements of the ternary lithium battery; The preset state of charge interval is determined based on the state of charge change characteristics of the ternary lithium battery during low-temperature charging. The test frequency range of the electrochemical impedance spectrum is determined based on the impedance response characteristics of the ternary lithium battery, and the test frequency range covers the mid-frequency charge transfer impedance and the low-frequency diffusion impedance.

4. The low-temperature energy-saving charging method based on the lithium plating start and end points according to claim 2, characterized in that, Obtaining the impedance characteristic parameters includes: At least two different preset relaxation times are set, and the electrochemical impedance spectra under different preset relaxation time conditions are obtained respectively; The junction impedance point between the mid-frequency charge transfer semicircular arc and the low-frequency diffusion region is determined from the Nyquist plot of the electrochemical impedance spectrum. The real part of the junction impedance point is taken as the impedance characteristic parameter, and the impedance characteristic parameter is defined as the resistance Rd at the mid-to-low frequency switching point; Plot the curves of the resistance Rd at the mid-to-low frequency switching point as a function of the state of charge under different preset relaxation time conditions.

5. The low-temperature energy-saving charging method based on the lithium plating start and end points according to claim 4, characterized in that, Determining the lithium plating start point and the lithium plating end point includes: When the difference between the resistance Rd at the mid-to-low frequency switching point under different preset relaxation time conditions is within a preset difference range, it is determined that the ternary lithium battery has not undergone lithium plating. When the resistance Rd at the mid-to-low frequency switching point under the first preset relaxation time condition is less than the resistance Rd at the mid-to-low frequency switching point under the second preset relaxation time condition and exceeds the preset difference range, it is determined that the ternary lithium battery has undergone lithium plating, wherein the second preset relaxation time is greater than the first preset relaxation time. The state of charge at which the lithium plating state changes from a state without lithium plating to a state with lithium plating is defined as the lithium plating initiation state of charge, and the voltage at the same moment is defined as the lithium plating initiation voltage. The lithium plating initiation point is constituted by the lithium plating initiation state and the lithium plating initiation voltage; The state of charge corresponding to the transition from the lithium plating state to the non-lithiation state is defined as the lithium plating termination state of charge, and the voltage at the same moment is defined as the lithium plating termination voltage. The lithium plating termination point is constituted by the lithium plating termination state and the lithium plating termination voltage.

6. The low-temperature energy-saving charging method based on the lithium plating start and end points according to claim 1, characterized in that, Establish the correspondence between charging conditions and lithium plating boundary parameters, including: The segmented charging test and the process of determining the lithium plating start point and the lithium plating end point are repeatedly performed under different low temperatures and different typical charging rates to obtain the lithium plating start point and the lithium plating end point under different preset low temperature charging conditions. Based on the lithium plating initiation points corresponding to different low-temperature temperatures under the same typical charging rate, determine the lithium plating initiation temperature corresponding to the typical charging rate; The lithium plating initiation temperature, the lithium plating initiation point, and the lithium plating termination point are established as a corresponding relationship according to the typical charging rate and the low temperature. Based on experimental data from multiple ternary lithium batteries in the same batch, a safety margin is set for the correspondence. The battery charging rate corresponding to the maximum charging power of different types of charging devices is used as the typical charging rate. The battery charging rates corresponding to slow charging devices, fast charging devices, and ultra-fast charging devices are included in the typical charging rate.

7. The low-temperature energy-saving charging method based on the lithium plating start and end points according to claim 6, characterized in that, Determining the charging status of the ternary lithium battery after it is connected to the charging equipment includes: When the ternary lithium battery is connected to the charging device, the current temperature, the current voltage, and the current state of charge are obtained through the battery management system; The maximum charging rate of the charging device is obtained through the battery management system, and the maximum charging rate is used as the charging rate. The lithium plating initiation temperature is found in the corresponding relationship based on the charging rate; When the current temperature is not lower than the lithium plating initiation temperature, the ternary lithium battery is charged according to the original charging method.

8. The low-temperature energy-saving charging method based on the lithium plating start and end points according to claim 7, characterized in that, The low-temperature energy-saving charging process of the ternary lithium battery includes: When the current temperature is lower than the lithium plating initiation temperature, the corresponding lithium plating initiation point and lithium plating termination point are found in the correspondence according to the charging rate and the current temperature; Under the original charging method, the current state of charge and the current voltage are continuously collected; When the current state of charge reaches the state of charge corresponding to the lithium plating start point or the current voltage reaches the voltage corresponding to the lithium plating start point, the original charging method is switched to constant voltage charging. During the constant voltage charging process, the voltage corresponding to the lithium plating initiation point is used as the constant voltage, and the charging current is reduced as the current state of charge increases. When the current state of charge reaches the state of charge corresponding to the lithium plating termination point, the constant voltage charging will be switched back to the original charging mode. Battery heating is not activated during the low-temperature charging control process of the ternary lithium battery. The low-temperature charging control method for ternary lithium batteries is applied to the low-temperature charging optimization of vehicles or energy storage systems powered by the ternary lithium batteries.

9. A low-temperature energy-saving charging system based on the lithium plating start and end points, characterized in that, The system includes: The segmented impedance acquisition module performs segmented charging tests on ternary lithium batteries under preset low-temperature charging conditions and acquires impedance characteristic parameters that characterize the changes in the lithium plating state of ternary lithium batteries during the segmented charging test. The lithium plating boundary determination module determines the lithium plating start point and lithium plating termination point of the ternary lithium battery under a preset low-temperature charging condition based on the difference in impedance characteristic parameters with the state of charge. The boundary relationship establishment module establishes the correspondence between the charging conditions and the lithium plating boundary parameters based on the lithium plating start point and lithium plating end point determined under different preset low temperature charging conditions. The charging status acquisition module acquires the current temperature, current voltage, current state of charge of the ternary lithium battery and the charging rate corresponding to the charging equipment after the ternary lithium battery is connected to the charging equipment. The current boundary matching module determines the lithium plating start point and lithium plating end point corresponding to the current charging condition in the corresponding relationship based on the current temperature and charging rate. The constant voltage switching control module switches the charging mode of the ternary lithium battery to constant voltage charging based on the voltage corresponding to the lithium plating start point when the current voltage or the current state of charge reaches the lithium plating start point. The charging recovery control module, when the current state of charge reaches the state of charge corresponding to the lithium plating termination point, causes the ternary lithium battery to exit constant voltage charging and resume the original charging mode.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, the computer program including program instructions, which, when executed by a processor, can implement the low-temperature energy-saving charging method based on the lithium plating start and end points as described in any one of claims 1-8.

11. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the low-temperature energy-saving charging method based on the lithium plating start and end points as described in any one of claims 1-8.

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