Lithium ion charging control method and device, equipment, medium and product

Abstract

The invention relates to a lithium ion charging control method and device, equipment, a medium and a product. The method comprises the following steps: acquiring state information of a lithium ion battery to be charged; the state information comprises a negative electrode potential value and a battery temperature value of the lithium ion battery to be charged; determining at least one charging current threshold value in the charging process of the to-be-charged lithium ion battery based on the state information and a preset mapping relation; the preset mapping relation comprises a mapping relation among a battery temperature value, a battery cathode potential value and a charging current value; the preset mapping relation is obtained by performing a charging test on the to-be-tested lithium ion battery according to negative electrode potential boundary values of the to-be-tested lithium ion battery at different charging rates at different battery temperatures; and controlling the charging current of the lithium ion battery to be charged according to the at least one charging current threshold value. By adopting the method, the charging current threshold value can be dynamically adjusted according to the charging state of the lithium ion battery, so that the safety of the lithium ion battery during fast charging is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium ion batteries, in particular to a lithium ion charging control method, device, equipment, medium and product. BACKGROUND

[0002] Lithium ion batteries are widely used in electric vehicles, new energy storage systems, portable electronic products and many other fields. Currently, users have increasing demands for the fast charging capability of lithium ion batteries. However, as the charging of the lithium ion battery proceeds, when the charging current exceeds a certain current threshold, lithium ions will be deposited in the form of metallic lithium, and the generation of metallic lithium will induce safety risks of the battery. Therefore, it is necessary to limit the charging current below the current threshold during the entire charging process.

[0003] Therefore, it is necessary to ensure the current threshold for limiting the charging current of the lithium ion battery to ensure the safety of the fast charging of the lithium ion battery. SUMMARY

[0004] Therefore, it is necessary to ensure the current threshold for limiting the charging current of the lithium ion battery to ensure the safety of the fast charging of the lithium ion battery.

[0005] In a first aspect, the present application provides a lithium ion charging control method, which comprises:

[0006] obtaining state information of a lithium ion battery to be charged; the state information comprises a negative electrode potential value and a battery temperature value of the lithium ion battery to be charged;

[0007] determining at least one charging current threshold in the charging process of the lithium ion battery to be charged based on the state information and a preset mapping relationship; the preset mapping relationship comprises a mapping relationship between the battery temperature value, the negative electrode potential value of the battery and the charging current value; the preset mapping relationship is obtained by charging test of the lithium ion battery to be tested according to the negative electrode potential boundary value of the lithium ion battery to be tested at different charging rates under different battery temperatures;

[0008] controlling the charging current of the lithium ion battery to be charged according to the at least one charging current threshold.

[0009] In one embodiment, the determination method of the preset mapping relationship comprises:

[0010] obtaining the actual temperature value and the actual negative electrode potential value of the lithium ion battery to be tested when the lithium ion battery to be tested is charged according to the starting current under the preset charging condition;

[0011] According to the negative electrode potential boundary value, the actual temperature value and the actual negative electrode potential value of the lithium ion battery to be measured at different charging rates under different battery temperatures, the adjustment value of the starting current is determined, and the charging current value of the lithium ion battery to be measured in the charging process is obtained;

[0012] According to the actual temperature value, the actual negative electrode potential value and the charging current value of the lithium ion battery to be measured in the charging process, a preset mapping relationship is established.

[0013] In one embodiment, according to the negative electrode potential boundary value, the actual temperature value and the actual negative electrode potential value of the lithium ion battery to be measured at different charging rates under different battery temperatures, the adjustment value of the starting current is determined, including:

[0014] According to the negative electrode potential boundary value of the lithium ion battery to be measured at different charging rates under different battery temperatures, the target negative electrode potential boundary value corresponding to the actual temperature value is determined.

[0015] If the actual negative electrode potential value is not greater than the target negative electrode potential boundary value, the adjustment value of the starting current is determined as a first value;

[0016] If the actual negative electrode potential value is greater than the target negative electrode potential boundary value, the adjustment value of the starting current is determined as a second value; the second value is greater than the first value.

[0017] In one embodiment, the method further comprises:

[0018] Obtaining the corresponding relationship between different charging rates and lithium precipitation nucleation negative electrode potential of the lithium ion battery to be measured under different temperatures;

[0019] For each battery temperature, according to the preset voltage threshold and the corresponding relationship, the negative electrode potential boundary value of the lithium ion battery to be measured at different charging rates is determined, and the negative electrode potential boundary value of the lithium ion battery to be measured at different charging rates under different battery temperatures is obtained.

[0020] In one embodiment, obtaining the corresponding relationship between different charging rates and lithium precipitation nucleation negative electrode potential of the lithium ion battery to be measured under different temperatures comprises:

[0021] For each battery temperature value, the negative electrode potential and the charging capacity of the lithium ion battery to be measured at different charging rates are obtained in real time;

[0022] According to the negative electrode potential and the charging capacity, a functional relationship between the negative electrode potential and a preset ratio is established; the preset ratio is the ratio between the negative electrode potential change amount and the charging capacity change amount;

[0023] Based on the zero point of the functional relationship, the lithium precipitation nucleation negative electrode potential of the lithium ion battery to be measured at different charging rates is determined;

[0024] Determine the corresponding relationship based on the lithium precipitation nucleation anode potential of the lithium ion battery to be tested at different charging rates of each battery temperature value.

[0025] In one embodiment, the corresponding relationship is determined based on the lithium precipitation nucleation anode potential of the lithium ion battery to be tested at different charging rates of each battery temperature value, including:

[0026] Determine the corresponding relationship based on the preset fitting method and the lithium precipitation nucleation anode potential of the lithium ion battery to be tested at different charging rates of each battery temperature value.

[0027] In a second aspect, the present application also provides a charging control device, which comprises:

[0028] A battery state acquisition module is configured to acquire state information of a lithium ion battery to be charged; the state information includes an anode potential value and a battery temperature value of the lithium ion battery to be charged;

[0029] A charging current determination module is configured to determine at least one charging current threshold in the charging process of the lithium ion battery to be charged based on the state information and a preset mapping relationship; the preset mapping relationship includes a mapping relationship between the battery temperature value, the battery anode potential value, and the charging current value; the preset mapping relationship is obtained by charging test on the lithium ion battery to be tested according to the anode potential boundary value of the lithium ion battery to be tested at different charging rates under different battery temperatures;

[0030] A battery charging control module is configured to control the charging current of the lithium ion battery to be charged according to the at least one charging current threshold.

[0031] In a third aspect, the present application also provides a computer device, which comprises a memory and a processor; the memory stores a computer program; and the processor implements the following steps when executing the computer program:

[0032] Acquire state information of a lithium ion battery to be charged; the state information includes an anode potential value and a battery temperature value of the lithium ion battery to be charged;

[0033] Determine at least one charging current threshold in the charging process of the lithium ion battery to be charged based on the state information and a preset mapping relationship; the preset mapping relationship includes a mapping relationship between the battery temperature value, the battery anode potential value, and the charging current value; the preset mapping relationship is obtained by charging test on the lithium ion battery to be tested according to the anode potential boundary value of the lithium ion battery to be tested at different charging rates under different battery temperatures;

[0034] Control the charging current of the lithium ion battery to be charged according to the at least one charging current threshold.

[0035] In a fourth aspect, the present application also provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement the following steps:

[0036] Obtaining state information of the lithium ion battery to be charged; the state information comprises a negative electrode potential value and a battery temperature value of the lithium ion battery to be charged;

[0037] Determining at least one charging current threshold in the charging process of the lithium ion battery to be charged based on the state information and a preset mapping relationship; the preset mapping relationship comprises a mapping relationship among the battery temperature value, the negative electrode potential value and the charging current value; the preset mapping relationship is obtained by performing charging test on the lithium ion battery to be tested according to the negative electrode potential boundary value of the lithium ion battery to be tested at different charging rates under different battery temperatures;

[0038] Controlling the charging current of the lithium ion battery to be charged according to the at least one charging current threshold.

[0039] In a fifth aspect, the present application also provides a computer program product, which comprises a computer program, and the computer program is executed by a processor to implement the following steps:

[0040] Obtaining state information of the lithium ion battery to be charged; the state information comprises a negative electrode potential value and a battery temperature value of the lithium ion battery to be charged;

[0041] Determining at least one charging current threshold in the charging process of the lithium ion battery to be charged based on the state information and a preset mapping relationship; the preset mapping relationship comprises a mapping relationship among the battery temperature value, the negative electrode potential value and the charging current value; the preset mapping relationship is obtained by performing charging test on the lithium ion battery to be tested according to the negative electrode potential boundary value of the lithium ion battery to be tested at different charging rates under different battery temperatures;

[0042] Controlling the charging current of the lithium ion battery to be charged according to the at least one charging current threshold.

[0043] The charging control method, device, equipment, medium and product of lithium ions provided by the above embodiments first acquire state information of a lithium ion battery to be charged, the state information including a negative electrode potential value and a battery temperature value of the lithium ion battery to be charged; then, at least one charging current threshold in a charging process of the lithium ion battery to be charged is determined based on a preset mapping relationship and the state information, so as to adjust the charging current according to the actual state of the lithium ion battery to be charged, avoid the occurrence of side reactions such as lithium precipitation caused by an excessively large charging current, and also improve the charging speed as much as possible under the premise of ensuring the safety of the battery; finally, the charging current of the lithium ion battery to be charged is controlled according to the at least one charging current threshold; in this way, the entire charging process of the lithium ion battery to be charged can be ensured to be performed within a safe current range, thereby also improving the safety and service life of the lithium ion battery to be charged. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 A flowchart of a charging control method of lithium ions provided for some embodiments of the present application;

[0045] Figure 2 A flowchart of establishing a preset mapping relationship provided for some embodiments of the present application;

[0046] Figure 3 A flowchart of determining an adjustment value of a starting current provided for some embodiments of the present application;

[0047] Figure 4 A flowchart of determining a negative electrode potential boundary value provided for some embodiments of the present application;

[0048] Figure 5 A flowchart of determining a corresponding relationship provided for some embodiments of the present application;

[0049] Figure 6 A structural block diagram of a charging control device provided for some embodiments of the present application;

[0050] Figure 7 An internal structural diagram of a computer device provided for some embodiments of the present application. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0052] The lithium-ion charging control method provided in this application can be applied to electric devices that use lithium-ion batteries, such as electric vehicles and power tools. Taking electric vehicles as an example, electric vehicles are usually equipped with a battery management system. During the charging process of lithium-ion batteries, the battery management system can obtain the status information of lithium-ion batteries in real time according to the lithium-ion charging control method of this application. The status information includes the temperature value and negative electrode potential value of the lithium-ion batteries. Based on the status information and a preset mapping relationship, at least one charging current threshold of the lithium-ion batteries during the charging process is determined so as to control the charging current of the lithium-ion batteries according to at least one charging current threshold, so as to avoid lithium plating reaction of lithium-ion batteries and the resulting safety problems.

[0053] In one embodiment, such as Figure 1 As shown, the method is illustrated using an example of an electric device employing a lithium-ion battery. In this embodiment, the method includes the following steps:

[0054] Step 102: Obtain the status information of the lithium-ion battery to be charged.

[0055] The term "lithium-ion battery to be charged" refers to a lithium-ion battery that requires charging. It can be used in various applications, such as power batteries for electric vehicles, mobile phone batteries, and laptop batteries. Status information includes the negative electrode potential and battery temperature of the lithium-ion battery to be charged. The negative electrode potential refers to the potential difference between the negative electrode and the reference electrode. This potential can be measured by the reference electrode inside the battery; common reference electrodes include lithium metal reference electrodes, lithium iron phosphate reference electrodes, and lithium titanate reference electrodes. The battery temperature refers to the temperature inside or on the surface of the lithium-ion battery, which can be obtained through a temperature sensor in the battery management system. The temperature sensor can be installed inside or on the surface of the lithium-ion battery to be charged.

[0056] Optionally, during the charging process of the lithium-ion battery, the negative electrode potential value of the lithium-ion battery can be obtained in real time through the reference electrode inside the lithium-ion battery, and the temperature value of the lithium-ion battery can be obtained in real time through the temperature sensor.

[0057] Step 104: Based on the state information and the preset mapping relationship, determine at least one charging current threshold during the charging process of the lithium-ion battery to be charged.

[0058] The preset mapping relationship includes a mapping relationship between the battery temperature value, the negative electrode potential value of the battery, and the charging current value. The preset mapping relationship is used to determine a suitable charging current threshold according to the state information (the negative electrode potential value and the battery temperature value) of the lithium ion battery to be charged. Through the mapping relationship, the charging current can be dynamically adjusted according to the actual state of the battery during the charging process, so as to ensure that the battery is charged quickly under the premise of safety.

[0059] Since the state information (the negative electrode potential value and the battery temperature value) of the lithium ion battery to be charged changes constantly during the charging process, in order to adapt to the change, the charging current needs to be dynamically adjusted according to different state information. Therefore, it can be necessary to determine a plurality of different charging current thresholds to meet the charging requirements of the battery in different states. For example, in the initial stage of charging, the battery state is good, and a larger charging current can be used; as the charging proceeds, the negative electrode potential gradually decreases, and in order to avoid the occurrence of side reactions such as lithium precipitation, the charging current needs to be reduced.

[0060] In addition, the preset mapping relationship is obtained by charging test on the lithium ion battery to be tested according to the negative electrode potential boundary value of the lithium ion battery to be tested at different charging rates under different battery temperatures. The lithium ion battery to be tested is a test battery specially used for experimental research, which is composed of a negative electrode, an electrolyte, and metal lithium of the lithium ion battery to be charged. The test battery is generally close in size to a button cell, so in order to simulate the charging condition of the test battery under different temperature environments, an external temperature control device is also used to simulate different temperature environments of the test battery. By charging test on the lithium ion battery to be tested, the negative electrode potential boundary value at different charging rates under different battery temperatures can be obtained, and thus the preset mapping relationship is established.

[0061] Optionally, the negative electrode potential value and the battery temperature value of the lithium ion battery to be charged currently obtained can be substituted into the preset mapping relationship to find the charging current value corresponding to the current negative electrode potential value and the battery temperature value, and the charging current value is the charging current threshold under the current state. In this way, at least one charging current threshold can be obtained during the entire charging process of the lithium ion battery to be charged.

[0062] Step 106: controlling the charging current of the lithium ion battery to be charged according to the at least one charging current threshold.

[0063] Optionally, during the charging process of the lithium ion battery to be charged, the current charging current value of the lithium ion battery to be charged is obtained in real time, and the current charging current value is compared with the charging current threshold obtained in step 104. In the case that the current charging current value is different from the charging current threshold, the charging current of the lithium ion battery to be charged is adjusted so as to not exceed the charging current threshold under the current state.

[0064] The charging control method of lithium ions first acquires state information of a lithium ion battery to be charged, the state information including a negative electrode potential value and a battery temperature value of the lithium ion battery to be charged; then determines at least one charging current threshold in a charging process of the lithium ion battery to be charged based on a preset mapping relationship, so as to adjust the charging current according to the actual state of the lithium ion battery to be charged, avoid the occurrence of side reactions such as lithium precipitation caused by too large charging current, and also improve the charging speed as much as possible under the premise of ensuring the safety of the battery; finally, controls the charging current of the lithium ion battery to be charged according to the at least one charging current threshold; in this way, the entire charging process of the lithium ion battery to be charged can be ensured to be carried out within a safe current range, thereby the safety and service life of the lithium ion battery to be charged can also be improved.

[0065] In one embodiment, as shown in FIG. 2, the determination method of the preset mapping relationship includes: Figure 2

[0066] Step 202: Acquire the actual temperature value and the actual negative electrode potential value of the lithium ion battery to be measured when the lithium ion battery to be measured is charged under a preset charging condition according to a starting current.

[0067] The preset charging condition can be a preset test condition, and the preset charging condition can include key factors affecting the charging process of the battery, such as a starting current step, a state of charge (SOC) of the battery, and an environmental temperature. The starting current step defines the charging size and the charging mode at the beginning of charging, for example, 4C (i.e., 7A) constant current charging, which clearly indicates that the initial stage is charged with a constant 7A current. Different starting currents will have a significant impact on the charging speed, heating condition, and negative electrode potential change of the battery.

[0068] The actual temperature value refers to the actual temperature of the lithium ion battery to be measured during the charging process, which can reflect the heating condition of the battery during charging. The actual negative electrode potential value refers to the actual potential of the negative electrode of the lithium ion battery to be measured relative to a reference electrode, which is used to reflect the embedding and extraction of lithium ions in the negative electrode material, and can also be used to judge whether the battery has side reactions such as lithium precipitation.

[0069] Optionally, it is assumed that the preset charging condition can be to charge the lithium ion battery to be measured by using a 4C (i.e., 7A) constant current charging mode; the SOC of the lithium ion battery to be measured is 10% in the initial state; the environmental temperature is 25°C; under the preset charging condition, the actual temperature value of the lithium ion battery to be measured is acquired by a temperature sensor installed on the surface or inside of the lithium ion battery to be measured, and the actual negative electrode potential value of the lithium ion battery to be measured is acquired by a reference electrode (such as a lithium metal reference electrode) inside the lithium ion battery to be measured. ​

[0070] Step 204, according to the negative electrode potential boundary value of the lithium ion battery to be tested at different charging rates under different battery temperatures, the actual temperature value and the actual negative electrode potential value, the adjustment value of the starting current is determined, and the charging current value of the lithium ion battery to be tested in the charging process is obtained.

[0071] Wherein, the adjustment value of the starting current is the value of increasing or decreasing the starting current based on certain conditions during the charging process of the lithium ion battery to be tested. It is a change amount for correcting the starting current, so that the charging current is more in line with the safety and performance requirements of the battery under different conditions.

[0072] It can be understood that during charging, if the starting current is too large, it may cause the negative electrode potential of the battery to be too low, triggering side reactions such as lithium precipitation, affecting the safety and life of the battery; if the starting current is too small, it will make the charging time too long and reduce the charging efficiency. By determining the appropriate starting current adjustment value, the charging current can be dynamically adjusted to make the battery complete charging as quickly as possible under the premise of safety.

[0073] Optionally, when the actual negative electrode potential value approaches or reaches the negative electrode potential boundary value, it indicates that the battery has the possibility of lithium precipitation and other dangers, and the starting current needs to be reduced at this time. For example, if the negative electrode potential boundary value corresponding to different charging rates at a certain temperature is known, when the actual negative electrode potential value reaches the boundary value, the current can be reduced according to the preset rule, such as reducing 0.1A each time; if the actual negative electrode potential value is far from the boundary value and the battery state is good, the starting current can be appropriately increased, such as increasing 0.05A each time.

[0074] Further, since the battery is more likely to precipitate lithium in a low-temperature environment, it may be necessary to more strictly control the charging current; while in a high-temperature environment, although the risk of lithium precipitation is relatively low, but too high current will cause the battery to overheat, also need to adjust the charging current appropriately. Therefore, different current adjustment coefficients can also be set according to the change of temperature. For example, at low temperature, when the actual negative electrode potential value approaches the boundary value, the charging current is reduced by 0.2A; at high temperature, when the actual negative electrode potential value approaches the boundary value, the charging current is reduced by 0.1A.

[0075] Step 206, according to the actual temperature value, the actual negative electrode potential value and the charging current value in the charging process of the lithium ion battery to be tested, a preset mapping relationship is established.

[0076] The charging test of the lithium-ion battery under test includes at least one of the following cutoff conditions: State of Charge (SOC) cutoff condition, Charge Capacity Cutoff condition, Terminal Voltage Cutoff condition, Negative Electrode Potential Cutoff condition, Current Cutoff condition, and Temperature Cutoff condition. The SOC cutoff condition can be that the lithium-ion battery's charge is 100%. The Charge Capacity Cutoff condition can be that the battery's rated capacity is 60%. The Terminal Voltage Cutoff condition can be that the terminal voltage reaches 4.2V. The Negative Electrode Potential Cutoff condition can be that when the negative electrode potential reaches -0.03V, charging is immediately stopped or the charging current is reduced. The Current Cutoff condition can be that charging is stopped when the charging current drops to 0.5A~1A. The Temperature Cutoff condition can be that charging is stopped when the battery temperature reaches 50℃.

[0077] Optionally, the actual temperature, actual negative electrode potential, and charging current of the lithium-ion battery under test during charging can be recorded in a table. Rows represent different actual temperature values, columns represent different actual negative electrode potential values, and elements in the table represent the corresponding charging current values. This method visually demonstrates the mapping relationship between the three and facilitates quick retrieval of the corresponding charging current value from the table based on the battery's real-time temperature and negative electrode potential. Alternatively, linear regression, multinomial regression, and neural network models can be used to fit the relationship between the actual temperature, actual negative electrode potential, and charging current values. Another option is to create a three-dimensional graph, where two axes represent the actual temperature and actual negative electrode potential, and the third axis represents the charging current. The graph allows for a clear observation of the trends and relationships among the three. In practical applications, the graph can be used to estimate the charging current value at different temperatures and negative electrode potentials. The specific method for establishing the preset mapping relationship can be determined based on actual usage requirements.

[0078] In this embodiment, by establishing a preset mapping relationship, the charging current can be dynamically adjusted according to the actual temperature and negative electrode potential of the lithium-ion battery to be charged. During the charging process, the state of the lithium-ion battery to be charged is monitored in real time. When the actual state of the lithium-ion battery to be charged approaches the danger boundary (such as the negative electrode potential approaching the boundary value), the charging current is adjusted in time to avoid safety problems such as lithium plating and overheating caused by excessive charging current, thereby improving the safety of lithium-ion battery charging.

[0079] In one embodiment, such as Figure 3 As shown, based on the negative electrode potential boundary value, actual temperature value, and actual negative electrode potential value of the lithium-ion battery under test at different charging rates and at different battery temperatures, the adjustment value of the starting current is determined, including:

[0080] Step 302: Determine the target negative electrode potential boundary value corresponding to the actual temperature value based on the negative electrode potential boundary values ​​of the lithium-ion battery under test at different charging rates under different battery temperatures.

[0081] The target negative electrode potential boundary value is a critical value of the negative electrode potential of the lithium ion battery to be measured at different charging rates at the current actual temperature. When the current negative electrode potential of the lithium ion battery to be measured is lower than the critical value, the risk of side reactions such as lithium precipitation of the battery will significantly increase, which may affect the safety and service life of the battery.

[0082] Optionally, the negative electrode potential boundary value data of the lithium ion battery to be measured at different charging rates at different battery temperatures need to be obtained in advance through experiments. These data are usually stored in the form of tables, curves or databases. Then, the negative electrode potential boundary value corresponding to the measured actual temperature value is found in the existing data. If the actual temperature value is equal to a certain temperature value in the data, the negative electrode potential boundary value corresponding to the temperature is directly taken as the target negative electrode potential boundary value. If the actual temperature value is between two known temperature values, the linear interpolation method can be used to estimate the target negative electrode potential boundary value. For example, the negative electrode potential boundary value corresponding to the temperature T1 is V1, the negative electrode potential boundary value corresponding to the temperature T2 is V2, and the actual temperature T satisfies T1 < T < T2. The target negative electrode potential boundary value V can be calculated by the formula V = V1 + (T-T1)*(V2-V1) / (T2-T1).

[0083] In step 304, if the actual negative electrode potential value is not greater than the target negative electrode potential boundary value, the adjustment value of the starting current is determined as the first value.

[0084] The first value is the adjustment value of the starting current when the actual negative electrode potential value is not greater than the target negative electrode potential boundary value. Usually, the first value is a negative number, indicating that the starting current needs to be reduced.

[0085] Optionally, the first value can be -0.1 A, which means that the starting current needs to be reduced by 0.1 A. This is because when the actual negative electrode potential value is not greater than the target negative electrode potential boundary value, it indicates that the negative electrode potential of the battery has approached or reached the dangerous boundary, and at this time, the charging current needs to be reduced to avoid further increasing the risk of lithium precipitation.

[0086] In step 306, if the actual negative electrode potential value is greater than the target negative electrode potential boundary value, the adjustment value of the starting current is determined as the second value.

[0087] The second value is the adjustment value of the starting current when the actual negative electrode potential value is greater than the target negative electrode potential boundary value. The second value is greater than the first value, and usually the second value can be 0 A or a positive number.

[0088] For example, if the second value is 0A, it means maintaining the current starting current unchanged; if the second value is a positive number, such as 0.05A, it means increasing the starting current by 0.05A. When the actual negative electrode potential value is greater than the target negative electrode potential boundary value, the surface battery is in good condition, and the charging current can be adjusted or the current value can be appropriately increased to further improve the charging rate of the battery on the basis of ensuring the safety of the battery charging.

[0089] In this embodiment, by monitoring the actual negative electrode potential value of the battery in real time and comparing it with the target negative electrode potential boundary value, and dynamically adjusting the starting current according to the comparison result, the occurrence of lithium precipitation and other side reactions during the charging process of the battery can be effectively avoided, thereby improving the safety of the lithium ion battery charging.

[0090] In one embodiment, as shown in Figure 4 The method further comprises:

[0091] Step 402: Obtain the corresponding relationship between different temperatures, different charging rates and lithium precipitation nucleation negative electrode potential of the lithium ion battery to be tested.

[0092] Optionally, a series of different temperature points can be set first, for example, -10℃, 0℃, 10℃, 20℃, 30℃, 40℃, etc., to simulate the use of the battery under different environmental temperatures; then for each temperature point, different charging rates can be set, such as 0.1C, 0.2C, 0.5C, 1C, 2C, etc. (C is the rated charge and discharge rate of the battery); then the lithium ion battery to be tested is placed in a specific temperature environment and charged at a certain charging rate, while the negative electrode potential of the battery is monitored in real time. During the charging process, the change of the negative electrode potential is closely observed, and when lithium precipitation nucleation occurs (which can be detected by electrochemical impedance spectroscopy, scanning electron microscopy, etc.), the negative electrode potential at this time is recorded, which is the lithium precipitation nucleation negative electrode potential under the temperature and charging rate; and multiple experiments are performed for each combination of temperature point and charging rate to obtain accurate and reliable data.

[0093] The lithium precipitation nucleation negative electrode potential data obtained by experiments under different temperatures and different charging rates are sorted to form a data set; and the corresponding relationship between different temperatures, different charging rates and lithium precipitation nucleation negative electrode potential is established by drawing a chart (such as a three-dimensional graph, in which the x-axis is the charging rate, the y-axis is the temperature, and the z-axis is the lithium precipitation nucleation negative electrode potential) or constructing a mathematical model (such as polynomial fitting, neural network model, etc.).

[0094] At step 404, for each battery temperature, a preset voltage threshold and a corresponding relationship are used to determine the negative electrode potential boundary value of the lithium ion battery under different charging rates, to obtain the negative electrode potential boundary value of the lithium ion battery under different charging rates at different battery temperatures.

[0095] wherein the preset voltage threshold is a safety threshold (≥ 0V), and the specific value of the safety threshold can be determined according to the characteristics of the specific negative electrode material. The negative electrode potential boundary value refers to a critical value of the negative electrode potential of the battery under different battery temperatures and different charging rates. When the actual negative electrode potential of the battery is lower than the boundary value, the risk of side reactions such as lithium precipitation of the battery will significantly increase.

[0096] Optionally, the lithium precipitation nucleation negative electrode potential obtained at step 402 can be added to the preset voltage threshold to obtain the corresponding negative electrode potential boundary value. For example, if the lithium precipitation nucleation negative electrode potential is -0.05V and the preset voltage threshold is 0V, then the negative electrode potential boundary value corresponding to the lithium precipitation nucleation negative electrode potential is -0.05V.

[0097] In this embodiment, by accurately obtaining the lithium precipitation characteristics of the battery under different conditions and determining a reasonable negative electrode potential boundary value, the occurrence of lithium precipitation during battery charging can be effectively avoided, the safety risk of the battery can be reduced, and the safe operation of the battery can be ensured.

[0098] In one embodiment, as shown in FIG. 2, the corresponding relationship between the different charging rates and the lithium precipitation nucleation negative electrode potential of the lithium ion battery under different temperatures is obtained, including: Figure 5

[0099] At step 502, for each battery temperature value, the negative electrode potential and the charging capacity of the lithium ion battery under different charging rates are obtained in real time.

[0100] wherein the negative electrode potential refers to the potential difference of the negative electrode relative to the reference electrode during the charging process of the lithium ion battery, and the negative electrode potential can be obtained by the reference electrode in the lithium ion battery. The charging capacity refers to the amount of electric charge flowing into the battery during the charging process, which is usually expressed in coulombs (C) or ampere-hours (Ah), and the charging capacity reflects the energy stored by the battery at different charging stages. The charging capacity can be obtained by the electric quantity meter chip in the battery management system.

[0101] At step 504, a function relationship between the negative electrode potential and the preset ratio is established according to the negative electrode potential and the charging capacity.

[0102] wherein the preset ratio is the ratio between the negative electrode potential change amount and the charging capacity change amount.

[0103] ​Optionally, during the charging process, the negative electrode potential V and the charging capacity Q can be recorded simultaneously at a certain time interval (such as 1 s) to obtain a series of discrete data points (V i , Q i ), where i is a positive integer; then the negative electrode potential change ΔVi=V i+1 -V i and the charging capacity change ΔQ i =Q i+1 -Q i between adjacent data points are calculated; then the preset ratio (dV / dQ) i =ΔV / ΔQ i corresponding to each data point is calculated; then the function relationship between the negative electrode potential V and the preset ratio dV / dQ is obtained by function fitting or the like with the negative electrode potential as the independent variable and the preset ratio dV / dQ as the dependent variable.

[0104] In step 506, the lithium precipitation nucleation negative electrode potential of the lithium ion battery to be tested at different charging rates is determined based on the zero point of the function relationship.

[0105] Optionally, the negative electrode potential corresponding to the zero point of the function relationship curve between the negative electrode potential V and the preset ratio dV / dQ is determined as the lithium precipitation nucleation negative electrode potential.

[0106] Since the change relationship between the negative electrode potential and the charging capacity will change obviously during the lithium precipitation nucleation process, the zero point of the function relationship curve is a key turning point of the change, which can reflect the time when the lithium precipitation phenomenon begins to appear, so as to accurately determine the lithium precipitation nucleation negative electrode potential.

[0107] In step 508, the corresponding relationship is determined based on the lithium precipitation nucleation negative electrode potential of the lithium ion battery to be tested at different charging rates at each battery temperature value.

[0108] Optionally, the lithium precipitation nucleation negative electrode potential data corresponding to different charging rates at each battery temperature value can be sorted first to form a three-dimensional data set, in which the three dimensions are the battery temperature T, the charging rate C, and the lithium precipitation nucleation negative electrode potential V nuc ; then the sorted data is made into a table, in which the rows represent the battery temperature, the columns represent the charging rate, and the elements in the table are the corresponding lithium precipitation nucleation negative electrode potential, so that the corresponding relationship of the lithium precipitation nucleation negative electrode potential at different temperatures and charging rates can be intuitively displayed; then a suitable data model is selected to describe the corresponding relationship, for example, a multivariate linear regression model, a neural network model, or the like can be used for fitting, so as to establish a mathematical corresponding relationship between the battery temperature, the charging rate, and the lithium precipitation nucleation negative electrode potential.

[0109] In the embodiment, the function relationship between the negative electrode potential and the preset ratio is established according to the negative electrode potential and the charging capacity, the lithium precipitation nucleation negative electrode potential of the lithium ion battery to be measured under different charging rates is determined, and the corresponding relationship between the lithium precipitation nucleation negative electrode potential and the charging rate under different temperatures of the lithium ion battery to be measured is determined based on the lithium precipitation nucleation negative electrode potential of the lithium ion battery to be measured under different charging rates at each battery temperature value. This is helpful to the accuracy of subsequent determination of the negative electrode potential boundary value, thereby ensuring the accuracy and reliability of the finally determined charging current threshold.

[0110] In one embodiment, the corresponding relationship is determined based on the lithium precipitation nucleation negative electrode potential of the lithium ion battery to be measured under different charging rates at each battery temperature value, including: determining the corresponding relationship based on a preset fitting method and the lithium precipitation nucleation negative electrode potential of the lithium ion battery to be measured under different charging rates at each battery temperature value.

[0111] The preset fitting method can be an interpolation fitting method, a linear fitting method, a polynomial fitting method, an exponential fitting method, a nonlinear least squares fitting method, etc.

[0112] Optionally, the preset fitting method in the embodiment can be an interpolation fitting method, specifically, a Lagrange interpolation method. For example, assuming that there are three different charging rates and corresponding lithium precipitation nucleation negative electrode potential data under the environment of 25 DEG C, the potential is 2.2V when the charging rate is 0.3C, the potential is 2.7V when the charging rate is 0.8C, and the potential is 3.1V when the charging rate is 1.2C. Assuming that the lithium precipitation nucleation negative electrode potential under the charging rate of 1C is to be predicted, the Lagrange interpolation method can construct a smooth curve according to the three known data points, let the curve pass through the three points, and then find the corresponding position of the charging rate of 1C on the curve, thereby obtaining the corresponding lithium precipitation nucleation negative electrode potential, which is calculated to be about 2.9V.

[0113] In the embodiment, the corresponding relationship between the lithium precipitation nucleation negative electrode potential and the charging rate under different temperatures of the lithium ion battery to be measured is determined based on the preset fitting method and the lithium precipitation nucleation negative electrode potential of the lithium ion battery to be measured under different charging rates at each battery temperature value. This can accurately judge the possibility of lithium precipitation of the battery under different use conditions, thereby ensuring the safe and stable operation of the battery.

[0114] It should be understood that although the steps in the flowcharts involved in the embodiments described above are shown in sequence according to the arrows, the steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, the execution of the steps is not strictly limited in sequence, and the steps can be executed in other orders. Moreover, at least some of the steps in the flowcharts involved in the embodiments described above can include multiple steps or multiple stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution order of the steps or stages is not necessarily sequential, but can be alternately or alternately executed with at least part of other steps or steps or stages in other steps.

[0115] Based on the same inventive concept, the embodiments of the present application also provide a charging control device for implementing the above-mentioned charging control method of lithium ions. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme described in the above method, so the specific limitations in one or more charging control device embodiments provided below can refer to the limitations of the charging control method of lithium ions described above, which will not be repeated here.

[0116] In one embodiment, as shown in Figure 6 A charging control device is provided, comprising: a battery state acquisition module 602, a charging current determination module 604, and a battery charging control module 606, wherein:

[0117] The battery state acquisition module 602 is configured to acquire state information of a lithium ion battery to be charged; the state information includes a negative electrode potential value and a battery temperature value of the lithium ion battery to be charged;

[0118] The charging current determination module 604 is configured to determine at least one charging current threshold in a charging process of the lithium ion battery to be charged based on the state information and a preset mapping relationship; the preset mapping relationship includes a mapping relationship between the battery temperature value, the negative electrode potential value of the battery, and the charging current value; the preset mapping relationship is obtained by charging test of the lithium ion battery to be tested according to the negative electrode potential boundary value of the lithium ion battery to be tested at different charging rates under different battery temperatures;

[0119] The battery charging control module 606 is configured to control the charging current of the lithium ion battery to be charged according to the at least one charging current threshold.

[0120] In one embodiment, the charging current determination module 604 comprises an actual data acquisition submodule, a charging current value determination submodule, and a mapping relationship determination submodule. The actual data acquisition submodule is configured to acquire actual temperature values and actual negative electrode potential values of the lithium ion battery under test when the lithium ion battery under test is charged according to a starting current under preset charging conditions. The charging current value determination submodule is configured to determine an adjustment value of the starting current according to the actual temperature values, the actual negative electrode potential values, and the negative electrode potential boundary values of the lithium ion battery under test at different charging rates under different battery temperatures, to obtain a charging current value of the lithium ion battery under test during the charging process. The mapping relationship determination submodule is configured to establish a preset mapping relationship according to the actual temperature values, the actual negative electrode potential values, and the charging current value of the lithium ion battery under test during the charging process.

[0121] In one embodiment, the charging current value determination submodule comprises a negative electrode potential boundary value determination unit and an adjustment value determination unit. The negative electrode potential boundary value determination unit is configured to determine a target negative electrode potential boundary value corresponding to the actual temperature value according to the negative electrode potential boundary values of the lithium ion battery under test at different charging rates under different battery temperatures. The adjustment value determination unit is configured to determine the adjustment value of the starting current as a first value if the actual negative electrode potential value is not greater than the target negative electrode potential boundary value, and determine the adjustment value of the starting current as a second value if the actual negative electrode potential value is greater than the target negative electrode potential boundary value. The second value is greater than the first value.

[0122] In one embodiment, the charging current determination module 604 further comprises a corresponding relationship determination submodule and a potential boundary value determination submodule. The corresponding relationship determination submodule is configured to acquire a corresponding relationship between different charging rates and lithium precipitation nucleation negative electrode potentials of the lithium ion battery under test at different temperatures. The potential boundary value determination submodule is configured to determine the negative electrode potential boundary values of the lithium ion battery under test at different charging rates according to a preset voltage threshold and the corresponding relationship for each battery temperature, to obtain the negative electrode potential boundary values of the lithium ion battery under test at different charging rates under different battery temperatures.

[0123] In one embodiment, the correspondence determination submodule includes a charging data acquisition unit, a function relationship establishment unit, a lithium nucleation negative electrode potential determination unit, and a correspondence determination unit. The charging data acquisition unit is used to acquire the negative electrode potential and charging capacity of the lithium-ion battery under test at different charging rates in real time for each battery temperature value. The function relationship establishment unit is used to establish a function relationship between the negative electrode potential and a preset ratio based on the negative electrode potential and the charging capacity. The preset ratio is the ratio between the change in negative electrode potential and the change in charging capacity. The lithium nucleation negative electrode potential determination unit is used to determine the lithium nucleation negative electrode potential of the lithium-ion battery under test at different charging rates based on the zero point of the function relationship. The correspondence determination unit is used to determine the correspondence based on the lithium nucleation negative electrode potentials of the lithium-ion battery under test at different charging rates for each battery temperature value.

[0124] In one embodiment, the correspondence determination unit is further configured to determine the correspondence based on a preset fitting method and the lithium nucleation negative electrode potentials of the lithium-ion battery under test at different charging rates for each battery temperature value.

[0125] Each module in the aforementioned charging control device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of a computer device in hardware form or independent of it, or stored in the memory of a computer device in software form, so that the processor can call and execute the operations corresponding to each module.

[0126] In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 7 As shown, the computer device includes a processor, memory, communication interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, mobile cellular networks, NFC (Near Field Communication), or other technologies. When executed by the processor, the computer program implements a lithium-ion charging control method. The display screen can be an LCD screen or an e-ink display screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad mounted on the computer device casing, or an external keyboard, touchpad, or mouse.

[0127] Those skilled in the art will understand that Figure 7The structure shown in the figure is only a block diagram of part of the structure related to the scheme of the present application, and does not constitute a limitation on the computer device to which the scheme of the present application is applied. The specific computer device can include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0128] In an embodiment, a computer device is provided, including a memory and a processor, the memory storing a computer program, and the processor implementing the steps in the above method embodiments when executing the computer program.

[0129] In an embodiment, a computer readable storage medium is provided, storing a computer program, and the computer program implementing the steps in the above method embodiments when executed by a processor.

[0130] In an embodiment, a computer program product is provided, including a computer program, and the computer program implementing the steps in the above method embodiments when executed by a processor.

[0131] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in the present application are all information and data authorized by the user or authorized by all parties.

[0132] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer readable storage medium, and when the computer program is executed, the processes of the above-mentioned embodiments of the methods can be included. Any reference to memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical storage, high-density embedded non-volatile memory, resistive memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration but not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The database involved in the embodiments provided in the present application can include at least one of a relational database and a non-relational database. The non-relational database can include a distributed database based on a block chain, etc., without being limited thereto. The processor involved in the embodiments provided in the present application can be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., without being limited thereto.

[0133] Any combination of the technical features of the above embodiments can be made. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combination of the technical features does not exist, it should be considered as the scope of the present application.

[0134] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of protection of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A charge control method of lithium ions, characterized by, The method comprises: obtaining state information of a lithium ion battery to be charged; the state information comprises a negative electrode potential value and a battery temperature value of the lithium ion battery to be charged; determining at least one charging current threshold in a charging process of the lithium ion battery to be charged based on the state information and a preset mapping relationship; the preset mapping relationship comprises a mapping relationship among the battery temperature value, the negative electrode potential value and the charging current value; the preset mapping relationship is obtained by charging test of the lithium ion battery to be measured according to the negative electrode potential boundary value of the lithium ion battery to be measured at different charging rates under different battery temperatures; controlling a charging current of the lithium ion battery to be charged according to the at least one charging current threshold.

2. The method of claim 1, wherein, The method for determining the preset mapping relationship comprises: obtaining an actual temperature value and an actual negative electrode potential value of the lithium ion battery to be measured when the lithium ion battery to be measured is charged at a starting current under preset charging conditions; determining an adjustment value of the starting current according to the negative electrode potential boundary value of the lithium ion battery to be measured at different charging rates under different battery temperatures, the actual temperature value and the actual negative electrode potential value, to obtain a charging current value of the lithium ion battery to be measured in the charging process; establishing the preset mapping relationship according to the actual temperature value, the actual negative electrode potential value and the charging current value of the lithium ion battery to be measured in the charging process.

3. The method of claim 2, wherein, The method for determining the adjustment value of the starting current according to the negative electrode potential boundary value of the lithium ion battery to be measured at different charging rates under different battery temperatures, the actual temperature value and the actual negative electrode potential value comprises: determining a target negative electrode potential boundary value corresponding to the actual temperature value according to the negative electrode potential boundary value of the lithium ion battery to be measured at different charging rates under different battery temperatures; if the actual negative electrode potential value is not greater than the target negative electrode potential boundary value, determining the adjustment value of the starting current as a first value; if the actual negative electrode potential value is greater than the target negative electrode potential boundary value, determining the adjustment value of the starting current as a second value; the second value is greater than the first value.

4. The method of claim 2, wherein, The method further comprises: obtaining a corresponding relationship between different charging rates and lithium precipitation nucleation negative electrode potential of the lithium ion battery to be measured under different temperatures; for each battery temperature, determining the negative electrode potential boundary value of the lithium ion battery to be measured at different charging rates according to a preset voltage threshold and the corresponding relationship, to obtain the negative electrode potential boundary value of the lithium ion battery to be measured at different charging rates under different battery temperatures.

5. The method of claim 4, wherein, The method for obtaining the corresponding relationship between different charging rates and lithium precipitation nucleation negative electrode potential of the lithium ion battery to be measured under different temperatures comprises: for each battery temperature value, obtaining the negative electrode potential and the charging capacity of the lithium ion battery to be measured at different charging rates in real time; establishing a functional relationship between the negative electrode potential and a preset ratio according to the negative electrode potential and the charging capacity; the preset ratio is a ratio between a negative electrode potential change amount and a charging capacity change amount. Determine, based on the zero point of the function relationship, a lithium precipitation nucleation negative electrode potential of the to-be-tested lithium ion battery at different charging rates; Determine, based on the lithium precipitation nucleation negative electrode potential of the to-be-tested lithium ion battery at different charging rates at each battery temperature value, the corresponding relationship.

6. The method of claim 5, wherein, The determining, based on the lithium precipitation nucleation negative electrode potential of the to-be-tested lithium ion battery at different charging rates at each battery temperature value, the corresponding relationship comprises: The determining, based on the lithium precipitation nucleation negative electrode potential of the to-be-tested lithium ion battery at different charging rates at each battery temperature value, the corresponding relationship comprises:

7. A charge control device, characterized by comprising: The apparatus comprises: A battery state acquisition module configured to acquire state information of a to-be-charged lithium ion battery; the state information comprises a negative electrode potential value and a battery temperature value of the to-be-charged lithium ion battery; A charging current determination module configured to determine at least one charging current threshold in a charging process of the to-be-charged lithium ion battery based on the state information and a preset mapping relationship; the preset mapping relationship comprises a mapping relationship among a battery temperature value, a battery negative electrode potential value, and a charging current value; the preset mapping relationship is obtained by charging test on a to-be-tested lithium ion battery according to a negative electrode potential boundary value of the to-be-tested lithium ion battery at different charging rates at different battery temperatures; A battery charging control module configured to control a charging current of the to-be-charged lithium ion battery according to the at least one charging current threshold. 8.A computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the computer device is configured to perform the method according to any one of claims 1-7. The processor, when executing the computer program, implements the steps of the method in any one of claims 1 to 6.

9. A computer readable storage medium having stored thereon a computer program, characterized in that, The computer program, when executed by the processor, implements the steps of the method in any one of claims 1 to 6.

10. A computer program product comprising a computer program, characterized in that, The computer program, when executed by the processor, implements the steps of the method in any one of claims 1 to 6.

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