Battery charging control method and device and battery management system

Abstract

The invention provides a battery charging control method and device and a battery management system.The method comprises the steps that in the charging test process of a battery, whether lithium precipitation happens to the battery or not is determined according to the anode potential of the battery, battery state parameters when lithium precipitation happens to the battery are obtained, and a charging strategy is generated according to the battery state parameters; therefore, adjustment guidance is provided for the charging rate of the battery in the actual charging process. Therefore, the charging strategy is formulated according to the battery state parameters when the battery sends lithium precipitation, so that the lithium precipitation risk can be effectively reduced in the actual charging process based on the guidance of the charging strategy, and the safety of battery charging is improved.

Description

Technical Field

[0001] The present application relates to the technical field of battery charging, and in particular to a battery charging control method, device and battery management system. Background Art

[0002] During the charging process of lithium-ion batteries, lithium ions will be deintercalated from the positive electrode and embedded in the negative electrode. However, when some abnormal conditions occur and the lithium ions deintercalated from the positive electrode cannot be embedded in the negative electrode, the lithium ions will precipitate on the surface of the negative electrode, forming a layer of gray material, which is called lithium deposition. Lithium deposition in the battery cell will not only cause the loss of active lithium and capacity of the battery cell, but in severe cases it will also cause the battery cell to short-circuit and cause safety problems. Therefore, how to improve the safety of batteries during charging is an urgent problem to be solved in the market. Summary of the invention

[0003] In view of the above problems, the present application provides a battery charging control method, device and battery management system, which can improve the safety of the battery during the charging process.

[0004] In a first aspect, the present application provides a battery charging control method, comprising: during a battery charging test process, determining whether lithium deposition occurs in the battery according to the anode potential of the battery, and obtaining battery status parameters when lithium deposition occurs in the battery; generating a charging strategy according to the battery status parameters, and the charging strategy is used to adjust the charging rate of the battery during the actual charging process.

[0005] In the above implementation process, during the battery charging test, it is determined whether the battery has lithium deposition according to the anode potential of the battery, and the battery state parameters when lithium deposition occurs are obtained, and a charging strategy is generated according to the battery state parameters, thereby providing adjustment guidance for the charging rate of the battery during the actual charging process. In this way, since the charging strategy is formulated according to the battery state parameters when the battery deposits lithium, the actual charging process guided by the charging strategy can effectively reduce the risk of lithium deposition and improve the safety of battery charging.

[0006] In some embodiments, determining whether lithium deposition occurs in the battery based on the anode potential of the battery includes: monitoring the anode potential of the battery cell and generating an anode potential curve based on the monitoring result; the anode potential curve is a curve characterizing the change of the anode potential over time; and determining whether lithium deposition occurs in the battery based on whether the slope of the anode potential curve is zero.

[0007] In the above implementation process, the slope of the anode potential curve is zero as the criterion for lithium deposition. Instead of relying on a fixed threshold, whether lithium deposition occurs is determined based on actual working conditions. This is consistent with the thermodynamic explanation of the lithium deposition process, making lithium deposition prediction more accurate.

[0008] In some embodiments, the battery cell includes a three-electrode battery cell; the monitoring of the anode potential of the battery cell includes: monitoring the real-time potential of the negative electrode of the battery cell and the real-time potential of a reference electrode; determining the anode potential based on the real-time potential of the negative electrode and the real-time potential of the reference electrode.

[0009] In the above implementation process, a specific method for monitoring the anode potential of the battery cell is provided.

[0010] In some embodiments, determining whether lithium deposition occurs in the battery based on whether the slope of the anode potential curve is zero includes: determining the slope of the anode potential curve at various time points, and determining the time point when the slope is zero as the lithium deposition time point; and determining that lithium deposition occurs in the battery when the battery reaches the lithium deposition time point.

[0011] In the above implementation process, a specific method for determining whether lithium deposition occurs in a battery is provided.

[0012] In some embodiments, determining the slope of the anode potential curve at each time point includes: obtaining a derivative function corresponding to a function of the anode potential curve; and obtaining the slope of the anode potential curve at each time point according to the derivative function.

[0013] In the above implementation process, a specific method for obtaining the slope of the anode potential curve at each time point is provided.

[0014] Further, in some embodiments, determining the time point when the slope is zero as the lithium deposition time point includes: determining whether the slopes corresponding to the Nth time point before the time point when the slope is zero and the Nth time point after the time point have the same sign; if the judgment result is no, determining the time point when the slope is zero as the lithium deposition time point.

[0015] In the above implementation process, by comparing the signs of the slopes corresponding to the Nth time point before and the Nth time point after the time point when the slope is zero, further confirmation is made as to whether the time point when the slope is zero is the lithium deposition time point. In this way, accidental errors can be effectively reduced and the accuracy of lithium deposition prediction can be improved.

[0016] Furthermore, in some embodiments, the battery status parameters include state of charge, battery cell temperature and charge rate.

[0017] In the above implementation process, optional types of battery status parameters obtained when lithium plating occurs in the battery are provided, laying a good data foundation for formulating a reasonable charging strategy.

[0018] Furthermore, in some embodiments, during the charging test, the initial charging rate of the battery is a first charging rate; after recording the charge state, temperature and charging rate of the battery at the lithium deposition time point, the method further includes: if the charge state of the battery at the lithium deposition time point is not 100%, continuing to perform a charging test on the battery at a second charging rate; the second charging rate is less than the first charging rate.

[0019] In the above implementation process, the charging test is performed at the initial charging rate, and the state of charge, temperature and charging rate are recorded after reaching the lowest point of the slope. At this time, if the state of charge of the battery has not reached 100%, a charging current less than the original charging rate is used to continue charging, and the previous steps are repeated until the battery cell reaches a fully charged state. In this way, the testing cost is effectively saved.

[0020] Furthermore, in some embodiments, the charging strategy includes state of charge safety margins and / or temperature safety margins corresponding to different charging rates.

[0021] In the above implementation process, the charging of the battery cell is controlled according to the two factors of SOC and temperature corresponding to the specific rate measured by the experimental group, and a charging strategy is formulated according to the charging SOC or charging temperature not higher than the measured one to reduce the risk of lithium plating in the battery cell.

[0022] Furthermore, in some embodiments, it also includes: during the actual charging process, if the state of charge of the battery reaches a state of charge safety boundary corresponding to the current charging rate, or the temperature of the battery reaches a temperature safety boundary corresponding to the current charging rate, reducing the current charging rate.

[0023] In the above implementation process, a specific method for adjusting the charging rate of the battery during the actual charging process based on the charging strategy is provided.

[0024] In a second aspect, the present application provides a battery charging control device, comprising: an acquisition module, used to determine whether lithium deposition occurs in the battery according to the anode potential of the battery during a battery charging test, and to obtain battery status parameters when lithium deposition occurs in the battery; a generation module, used to generate a charging strategy according to the battery status parameters, and the charging strategy is used to adjust the charging rate of the battery during the actual charging process.

[0025] In a third aspect, the present application provides a battery management system, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the method described in any one of the first aspects are implemented.

[0026] In a fourth aspect, the present application provides a computer-readable storage medium having instructions stored thereon. When the instructions are executed on a computer, the computer is caused to execute the method as described in any one of the first aspects.

[0027] In a fifth aspect, the present application provides a computer program product, which, when executed on a computer, enables the computer to execute the method as described in any one of the first aspects.

[0028] Other features and advantages disclosed in the present application will be described in the following description, or some features and advantages can be inferred or determined without doubt from the description, or can be learned by implementing the above-mentioned technology disclosed in the present application.

[0029] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 A flowchart of a battery charging control method provided in some embodiments of the present application;

[0032] Figure 2 A schematic diagram of a change in the anode potential of a battery cell during a battery charging test provided by some embodiments of the present application, wherein the horizontal axis is the test time in seconds (s), and the vertical axis is the anode potential of the battery cell in volts (V);

[0033] Figure 3 A block diagram of a battery charging control device provided in some embodiments of the present application;

[0034] Figure 4 A structural block diagram of a battery management system provided for some embodiments of the present application. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0036] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0037] Currently, lithium-ion batteries are widely used as power batteries for electric vehicles. Since the negative electrode materials of lithium-ion batteries are mostly carbon materials mainly composed of graphite, which have a low potential for lithium, lithium-ion batteries are prone to precipitating metallic lithium at the negative electrode during charging. Lithium precipitation in the battery cell will not only cause loss of active lithium and capacity of the battery cell, but in severe cases will also cause short circuit of the battery cell, causing safety problems. Therefore, how to improve the safety of batteries during charging is an urgent problem to be solved in the market.

[0038] In response to the above technical problems, an embodiment of the present application provides a battery charging control method. During the battery charging test process, the anode potential of the battery is used as the basis for judging lithium plating, and the battery state parameters when lithium plating occurs are obtained. A charging strategy is formulated based on this, and guidance is provided for adjusting the charging rate of the battery during the actual charging process, so that the battery cell reduces the risk of lithium plating and improves charging safety.

[0039] Next, the embodiments of the present application are introduced:

[0040] like Figure 1 As shown, Figure 1 It is a flow chart of a battery charging control method provided in an embodiment of the present application, and the method can be applied to a battery management system (BMS).

[0041] The method comprises:

[0042] Step 101: during a battery charging test, determining whether lithium deposition occurs in the battery according to the anode potential of the battery, and obtaining battery state parameters when lithium deposition occurs in the battery;

[0043] The battery mentioned in this step can be any lithium-ion battery. During the charging process, when the anode potential of the battery is reduced to the lithium precipitation potential, lithium ions are deposited on the anode surface in the form of metallic lithium. Based on this, in the test phase, the present embodiment performs constant current charging on the battery and monitors the anode potential of the battery to determine whether lithium deposition occurs in the battery. When it is determined that lithium deposition occurs in the battery, the corresponding battery status parameters are obtained to lay a good data foundation for the subsequent formulation of a reasonable charging strategy.

[0044] When determining whether lithium deposition occurs in a battery according to the anode potential, 0mV (millivolt) can be used as the threshold value for lithium deposition, that is, when the anode potential is 0mV, it is determined that lithium deposition occurs in the battery. The applicant has experimentally found that during the battery charging process, the anode potential gradually decreases as the lithium ion embedding potential reaches 0mV. Since lithium deposition occurs when lithium ions are reduced to lithium atoms on the graphite surface, lithium atoms can further grow to form lithium dendrites after diffusion and aggregation and nucleation, and a certain nucleation barrier needs to be overcome during nucleation. Therefore, when lithium deposition occurs, the anode potential needs to be reduced to a lower value, that is, a certain overpotential is required for actual lithium deposition, so the anode potential will be further reduced. Once the nucleation stage is passed, lithium ions will rapidly grow and extend on the surface of the lithium nucleus and enter a stable growth stage. The corresponding growth overpotential is smaller than the nucleation overpotential, so after nucleation is completed, the anode potential will increase as charging proceeds, and the corresponding anode potential is the lowest during nucleation. Therefore, based on this discovery, in order to improve the accuracy of lithium deposition prediction, in some embodiments, determining whether lithium deposition occurs in the battery according to the anode potential of the battery mentioned in this step may include: monitoring the anode potential of the battery cell, and generating an anode potential curve based on the monitoring result; the anode potential curve is a curve that characterizes the change of the anode potential over time; and determining whether lithium deposition occurs in the battery according to whether the slope of the anode potential curve is zero. In other words, the slope of the anode potential curve is zero as the criterion for lithium deposition, and it is no longer based on a fixed threshold, but is judged based on the actual working conditions to determine whether lithium deposition occurs. In this way, it conforms to the thermodynamic explanation of the lithium deposition process, making the lithium deposition prediction more accurate.

[0045] refer to Figure 2 , Figure 2 This is a schematic diagram of the change of the anode potential of a battery cell during a battery charging test provided in an embodiment of the present application. The horizontal axis of the schematic diagram is the test time, in seconds (s), and the vertical axis is the anode potential of the battery cell, in volts (V). In implementation, the battery is charged with a constant current at a charging rate of 2C, and the anode potential of the battery cell is monitored. By curve fitting, a curve characterizing the change of the anode potential of the battery cell over time, i.e., the anode potential curve, is obtained. Then, the time point corresponding to the slope of the anode potential curve being zero is obtained. Figure 2 In the graph, point A is the time point when the anode potential of the battery cell is 0V, and point B is the time point when the slope of the anode potential curve is 0. Point A to point B is the nucleation stage, and point B to point C is the growth stage. Therefore, point B is the time point when lithium deposition actually occurs in the battery cell. Therefore, recording the battery state parameters at this time point can lay a good data foundation for the subsequent formulation of a reasonable charging strategy.

[0046] Specifically, in some embodiments, the battery cell mentioned in this step may include a three-electrode battery cell. That is, the battery cell may include a positive electrode, a negative electrode, and a reference electrode. When implemented, an actual hard shell battery cell may be implanted with three electrodes to detect the anode potential to avoid temperature differences in small stacks. At this time, the aforementioned monitoring of the anode potential of the battery cell may include: monitoring the real-time potential of the negative electrode of the battery cell and the real-time potential of the reference electrode; determining the anode potential according to the real-time potential of the negative electrode and the real-time potential of the reference electrode. That is to say, during the battery charging test process, the real-time potential of the negative electrode and the real-time potential of the reference potential can be obtained periodically or in real time, and the difference between the real-time potential of the negative electrode and the real-time potential of the reference potential is determined as the anode potential, so as to achieve monitoring of the anode potential of the battery cell.

[0047] In some embodiments, the aforementioned determination of whether lithium deposition occurs in the battery according to whether the slope of the anode potential curve is zero may include: determining the slope of the anode potential curve at each time point, determining the time point with the slope of zero as the lithium deposition time point; and determining that lithium deposition occurs in the battery when the battery reaches the lithium deposition time point. That is, after establishing the anode potential curve according to the monitored data, the battery management system may determine the slope of the anode potential curve at each time point, and determine the time point with the slope of zero as the lithium deposition time point, that is, the time point when lithium deposition occurs in the battery. Optionally, the determination of the slope of the anode potential curve at each time point may include: obtaining the derivative function corresponding to the function of the anode potential curve; and obtaining the slope of the anode potential curve at each time point according to the derivative function. That is, after establishing the anode potential curve according to the monitored data, the function of the anode potential curve may be obtained, and then the derivative function of the function may be solved. After that, each time point may be substituted into the derivative function to obtain the slope of the anode potential curve at each time point.

[0048] Moreover, considering that in some special cases, the anode potential detected by the three electrodes remains unchanged for a short time and then continues to decrease, therefore, determining the time point with a slope of zero as the lithium precipitation time point here may include: judging whether the slopes corresponding to the Nth time point before the time point with a slope of zero and the Nth time point after the time point with a slope of zero have the same sign; if the judgment result is no, determining the time point with a slope of zero as the lithium precipitation time point. That is to say, in the case of determining that there is a time point with a slope of zero, if the time point is a lithium precipitation time point, since the time point before the lithium precipitation time point is the nucleation stage, the anode potential is on a downward trend, so the slope of the first N time points should be negative, and after the nucleation is completed, the anode potential is on an upward trend, so the slope of the N time points thereafter should be positive, that is, the slope signs corresponding to the Nth time point before it and the Nth time point after it are inconsistent. On the contrary, if the slope corresponding to a time point is zero, but the slope signs corresponding to the Nth time point before the time point and the Nth time point after the time point are consistent, it indicates that the time point is not a lithium precipitation time point. In this way, accidental errors can be effectively reduced and the accuracy of lithium precipitation prediction can be further improved.

[0049] Also, in some embodiments, the battery state parameters mentioned in this step may include state of charge, cell temperature and charge rate. That is to say, when it is determined that lithium deposition occurs in the battery, the battery management system can record the state of charge, cell temperature and charge rate of the battery at the time of lithium deposition, so as to formulate a charging strategy that can effectively reduce the risk of lithium deposition in the battery. Among them, the state of charge of the battery at the time of lithium deposition can be obtained based on the ratio between the capacity corresponding to the cell at the time of lithium deposition and the standard capacity of the cell. For example, if the standard capacity of the cell is C0, and the capacity of the cell is C1 when the slope of the anode potential curve is 0, then the state of charge SOC of the battery at the time of lithium deposition = C1 / C0*100%. Of course, in other embodiments, the battery management system can also obtain other state parameters of the battery at the time of lithium deposition, such as internal resistance, charging time, etc., according to the needs of specific scenarios.

[0050] Further, in some embodiments, during the aforementioned charging test, the initial charging rate of the battery is the first charging rate; after obtaining the battery state parameters when lithium deposition occurs in the battery, it may include: if the state of charge of the battery at the lithium deposition time point is not 100%, the battery is continued to be charged at the second charging rate; the second charging rate is less than the first charging rate. That is to say, the charging test is performed at the initial charging rate, and the state of charge, temperature and charging rate are recorded after reaching the lowest point of the slope. At this time, if the state of charge of the battery does not reach 100%, then the charging current is switched to a charging current less than the original charging rate to continue charging, and the previous steps are repeated until the battery reaches a fully charged state. For example, the battery is first charged with a constant current at a 2C charging rate, and the state of charge of the battery at the lithium deposition time point is 70%, then the charging current is switched to 1C to continue charging, and if the battery still does not reach a 100% fully charged state when the slope of the anode potential curve is 0, then the charging current is switched to 0.5C to continue charging. In this way, the testing cost is effectively saved.

[0051] Step 102: Generate a charging strategy according to the battery status parameter, wherein the charging strategy is used to adjust the charging rate of the battery during an actual charging process.

[0052] The battery management system can, according to the preset strategy, determine the vehicle's charging process at the designated charging station as the charging test process, and determine the charging process at the remaining charging stations as the actual charging process. In this way, the battery management system can obtain the battery status parameters of the battery at the lithium plating time point during the battery charging test process, thereby generating a charging strategy and applying it to the actual charging process of the battery, that is, adjusting the charging rate according to the real-time state of charge and real-time temperature of the battery, thereby reducing the risk of lithium plating of the battery cell and improving the charging efficiency of the battery.

[0053] In some embodiments, the charging strategy may include a state of charge safety boundary and / or a temperature safety boundary corresponding to different charging rates. The state of charge safety boundary here may refer to the upper limit of the state of charge when the battery is charged, and accordingly, the temperature safety boundary may refer to the upper limit of the temperature when the battery is charged. That is to say, the charging of the battery cell is controlled according to the two elements of SOC and temperature corresponding to the specific rate measured by the experimental group, and a charging strategy is formulated according to the charging SOC or charging temperature not higher than the measured charging SOC to ensure that the battery cell will not precipitate lithium. For example, at 25°C, the battery is charged and tested with a charging current of 2C, and the state of charge of the battery at the time of lithium precipitation is recorded to be 70% and the temperature is 40°C. Then, a charging strategy generated based on this information can be a battery state of charge safety boundary of 70% and a temperature safety boundary of 40°C at a 2C charging rate, that is, the battery charging SOC is not higher than 70%, and the charging temperature is not higher than 40°C. In this way, the risk of lithium precipitation is effectively reduced and the safety of battery charging is improved.

[0054] Furthermore, in some embodiments, the method may further include: during the actual charging process, if the state of charge of the battery reaches the state of charge safety boundary corresponding to the current charging rate, or the temperature of the battery reaches the temperature safety boundary corresponding to the current charging rate, reducing the current charging rate. That is, during the actual charging process of the battery, the battery management system may adjust the charging rate of the battery based on the charging strategy. Using the previous example, one of the charging strategies stored in the battery management system is that the battery's state of charge safety boundary is 70% and the temperature safety boundary is 40°C at a 2C charging rate. In the actual charging process, the battery management system can first adjust the starting charging rate to 2C. When the battery's state of charge increases to 68%, it is considered to have reached the corresponding state of charge safety boundary at the current charging rate, or when the battery's temperature increases to 38°C, it is considered to have reached the corresponding temperature safety boundary at the current charging rate. At this time, the battery management system can adjust the charging rate to 1C to continue charging, and control it according to the corresponding charging strategy at the 1C charging rate. If the battery's state of charge reaches the corresponding state of charge safety boundary at the 1C charging rate, or the battery's temperature reaches the corresponding temperature safety boundary at the 1C charging rate, the battery management system will adjust the charging rate to 0.5C again to continue charging until the battery reaches a full charge state. In this way, a smaller rate is used in turn to perform step charging to different depths of SOC states, forming a complete charging process, maintaining the battery's charging efficiency while improving charging safety.

[0055] In the embodiment of the present application, during the battery charging test process, it is determined whether the battery has lithium deposition according to the anode potential of the battery, and the battery state parameters when lithium deposition occurs are obtained, and a charging strategy is generated according to the battery state parameters, thereby providing adjustment guidance for the charging rate of the battery during the actual charging process. In this way, since the charging strategy is formulated according to the battery state parameters when the battery deposits lithium, the actual charging process guided by the charging strategy can effectively reduce the risk of lithium deposition and improve the safety of battery charging.

[0056] The following is a charging test process provided in an embodiment of the present application, which may include the following steps:

[0057] A1. Prepare reference electrode: select copper wire with a diameter of about 6μm, soak the copper wire in concentrated sulfuric acid for 50min to remove the surface oxide layer, then rinse it with deionized water three times, rinse it with ethanol three times, dry it, and observe whether the surface oxide layer of the copper wire is completely removed under CCD. If not, repeat the above steps to remove the oxide layer until the surface oxide layer is completely removed;

[0058] A2. Prepare positive electrode sheets: stir and mix positive electrode materials such as NCM811, conductive agents (such as carbon black), binders (such as polyvinylidene fluoride), and N-methylpyrrolidone (NMP) in a weight ratio of 67.34:3.0:2.7:25 to obtain positive electrode slurry, and then evenly coat the positive electrode slurry on the positive electrode collector, and then dry, cold press, and cut to obtain positive electrode sheets;

[0059] A3. Preparation of negative electrode sheets: dissolving active material artificial graphite, conductive agent (such as carbon black), and binder (such as polyvinylidene fluoride) in a solvent (such as deionized water) at a weight ratio of 96.0:2.0:2.0, and preparing negative electrode slurry after evenly mixing. Then, evenly coating the negative electrode slurry on the negative electrode collector copper foil once or multiple times, and then drying, cold pressing, and cutting to obtain negative electrode sheets. Among them, the capacity of the prepared negative electrode graphite is lower than the capacity of the positive electrode, creating conditions for lithium precipitation of the overcharged negative electrode;

[0060] A4. Prepare electrolyte: In an argon atmosphere glove box (H2O<0.1ppm, O2<0.1ppm), mix organic solvent ethylene carbonate (EC) / ethyl methyl carbonate (EMC) in a volume ratio of 3 / 7, add 12.5% ​​LiPF6 lithium salt and dissolve it in the organic solvent, stir evenly, and obtain electrolyte;

[0061] A5. Choose the isolation film: Use polypropylene film as the isolation film;

[0062] A6. Prepare three electrodes: Assemble the above materials into a laminated battery in the following order: positive electrode sheet, separator, negative electrode sheet, separator, reference electrode, separator, positive electrode sheet;

[0063] A7. Lithium plating of reference electrode: connect the positive electrode of the battery to the reference electrode, charge it with a current of 10μA for two hours, and plate lithium on the side of the reference electrode close to the positive electrode. Similarly, connect the negative electrode of the battery to the reference electrode, charge it with a current of 10μA for two hours, and plate lithium on the side of the reference electrode close to the negative electrode.

[0064] A8. Check the three electrodes: Use a multimeter to detect the positive and negative voltages V1, and the positive and reference voltages V2, and the reference and negative voltages V3. If V1 = V2 + V3, the three electrodes are normal, and continue to the next step of the test. Otherwise, prepare the three electrodes again.

[0065] A9. Test: During the battery charging and discharging process, monitor the reference / negative electrode potential. At 25°C, charge the three-electrode cell at a constant current of 2C. Record the charge state and temperature of the three-electrode cell when the slope of the anode potential curve is 0. At this time, the negative electrode potential change process of the three-electrode cell is as follows: Figure 2As shown; when the recorded state of charge is not 100%, reduce the charging rate to 1C and repeat the test steps until the SOC is 100%, that is, fully charged.

[0066] Corresponding to the embodiments of the aforementioned method, the present application also provides embodiments of a battery charging control device and a terminal using the same:

[0067] like Figure 3 As shown, Figure 3 is a block diagram of a battery charging control device provided in an embodiment of the present application, the device comprising:

[0068] An acquisition module 31 is used to determine whether lithium deposition occurs in the battery according to the anode potential of the battery during a battery charging test, and to acquire a battery state parameter when lithium deposition occurs in the battery;

[0069] The generating module 32 is used to generate a charging strategy according to the battery status parameter, wherein the charging strategy is used to adjust the charging rate of the battery during the actual charging process.

[0070] The implementation process of the functions and effects of each module in the above-mentioned device is specifically described in the implementation process of the corresponding steps in the above-mentioned method, which will not be repeated here.

[0071] This application also provides a battery management system, see Figure 4 , Figure 4 A structural block diagram of a battery management system provided in an embodiment of the present application. The battery management system may include a processor 410, a communication interface 420, a memory 430, and at least one communication bus 440. Among them, the communication bus 440 is used to realize the direct connection and communication of these components. Among them, the communication interface 420 of the battery management system in the embodiment of the present application is used to communicate signaling or data with other node devices. The processor 410 can be an integrated circuit chip with signal processing capabilities.

[0072] The processor 410 may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it may also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components. The methods, steps and logic block diagrams disclosed in the embodiments of the present application may be implemented or executed. The processor 410 may be a microprocessor, or the processor 410 may be any conventional processor, etc.

[0073] The memory 430 may be, but is not limited to, a random access memory (RAM), a read only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electric erasable programmable read-only memory (EEPROM), etc. The memory 430 stores computer-readable instructions. When the computer-readable instructions are executed by the processor 410, the battery management system may execute the above-mentioned Figure 1 The method embodiment involves various steps.

[0074] Optionally, the battery management system may further include a storage controller and an input-output unit.

[0075] The memory 430, storage controller, processor 410, peripheral interface, input and output unit components are directly or indirectly electrically connected to each other to achieve data transmission or interaction. For example, these components can be electrically connected to each other via one or more communication buses 440. The processor 410 is used to execute executable modules stored in the memory 430, such as software function modules or computer programs included in the battery management system.

[0076] The input and output unit is used to provide users with the task creation and to create a start optional time period or preset execution time for the task to realize the interaction between the user and the server. The input and output unit can be, but is not limited to, a mouse and a keyboard.

[0077] Understandably, Figure 4 The structure shown is for illustration only. The battery management system may also include Figure 4 More or fewer components as shown, or with Figure 4 Different configurations are shown. Figure 4 Each component shown in the figure can be implemented by hardware, software or a combination thereof.

[0078] An embodiment of the present application further provides a storage medium having instructions stored thereon. When the instructions are run on a computer, the computer program is executed by a processor to implement the method described in the method embodiment. To avoid repetition, the method will not be described here.

[0079] The present application also provides a computer program product, which, when executed on a computer, enables the computer to execute the method described in the method embodiment.

[0080] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the devices, methods and computer program products according to multiple embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, a program segment or a part of a code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0081] In addition, the functional modules in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

[0082] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium, including several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0083] The above description is only an embodiment of the present application and is not intended to limit the scope of protection of the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0084] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0085] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

Claims

1. A battery charging control method, characterized in that: include: During the battery charging test, determining whether lithium deposition occurs in the battery according to the anode potential of the battery, and obtaining the battery state parameters when lithium deposition occurs in the battery; A charging strategy is generated according to the battery status parameter, and the charging strategy is used to adjust the charging rate of the battery during an actual charging process.

2. The battery charging control method according to claim 1, characterized in that: The step of determining whether lithium deposition occurs in the battery according to the anode potential of the battery comprises: Monitoring the anode potential of the battery cell of the battery, and generating an anode potential curve based on the monitoring result; the anode potential curve is a curve representing the change of the anode potential over time; Whether lithium deposition occurs in the battery is determined according to whether the slope of the anode potential curve is zero.

3. The battery charging control method according to claim 2, characterized in that: The battery cell comprises a three-electrode battery cell; the step of monitoring the anode potential of the battery cell comprises: Monitoring the real-time potential of the negative electrode of the battery cell and the real-time potential of the reference electrode; The anode potential is determined according to the real-time potential of the negative electrode and the real-time potential of the reference electrode.

4. The battery charging control method according to claim 2 or 3, characterized in that: The step of determining whether lithium deposition occurs in the battery according to whether the slope of the anode potential curve is zero comprises: Determine the slope of the anode potential curve at each time point, and determine the time point when the slope is zero as the lithium deposition time point; When the battery reaches the lithium deposition time point, it is determined that lithium deposition occurs in the battery.

5. The battery charging control method according to claim 4, characterized in that: Determining the slope of the anode potential curve at each time point includes: Obtaining a derivative function corresponding to the function of the anode potential curve; The slope of the anode potential curve at each time point is obtained according to the derivative function.

6. The battery charging control method according to claim 4, characterized in that: Determining the time point at which the slope is zero as the lithium deposition time point comprises: Determine whether the slopes corresponding to the Nth time point before the time point at which the slope is zero and the Nth time point after the time point have the same sign; If the judgment result is no, the time point when the slope is zero is determined to be the lithium deposition time point.

7. The battery charging control method according to any one of claims 1 to 6, characterized in that: The battery status parameters include state of charge, battery cell temperature and charge rate.

8. The battery charging control method according to any one of claims 1 to 7, characterized in that: During the charging test, the initial charging rate of the battery is a first charging rate; after obtaining the battery state parameter when lithium deposition occurs in the battery, the method includes: If the state of charge of the battery at the lithium deposition time point is not 100%, the battery is continuously charged and tested using a second charging rate; the second charging rate is less than the first charging rate.

9. The battery charging control method according to claim 7, characterized in that: The charging strategy includes a state of charge safety margin and / or a temperature safety margin corresponding to different charging rates.

10. The battery charging control method according to claim 9, characterized in that: Also includes: During the actual charging process, if the state of charge of the battery reaches the state of charge safety boundary corresponding to the current charging rate, or the temperature of the battery reaches the temperature safety boundary corresponding to the current charging rate, the current charging rate is reduced.

11. A battery charging control device, characterized in that: The device comprises: An acquisition module, used to determine whether lithium deposition occurs in the battery according to the anode potential of the battery during a battery charging test, and to acquire battery state parameters when lithium deposition occurs in the battery; A generating module is used to generate a charging strategy according to the battery status parameters, wherein the charging strategy is used to adjust the charging rate of the battery during an actual charging process.

12. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed by a processor, the method according to any one of claims 1 to 10 is implemented.

13. A battery management system, characterized in that: The method comprises a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the method according to any one of claims 1 to 10 is implemented.

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