Battery charging methods, electronic devices and electrical equipment

Abstract

Embodiments of the present invention provide a battery charging method, electronic equipment, and electrical equipment. The charging method provided by the present invention, by alternating between high-current and low-current charge / discharge cycles during a rapid charging cycle, eliminates polarization caused by rapid charging at high currents, improves lithium deposition at the interface, prevents abnormal voltage drops in cells, and homogenizes local differences in interface SOC caused by rapid charging. On the other hand, low-current charging reduces variations in cell temperature rise, suppresses localized overcharging and over-discharging phenomena, and improves lithium deposition while simultaneously extending the effective life of the battery. Thus, it solves the problem that conventional charging methods cannot improve lithium deposition on the battery anode while guaranteeing rapid charging performance.

Description

[Technical Field]

[0001] This application relates to the field of battery control technology, and more particularly to battery charging methods, electronic devices, and electrical equipment. [Background technology]

[0002] Currently, the need for fast charging of electric vehicles is increasing to improve the user experience of driving, and battery charging rates continue to rise.

[0003] Conventional methods for improving rapid charging include pulse charging, variable current charging, and variable voltage charging, which can shorten the effective rapid charging time to 10-30 minutes, greatly satisfying users' rapid charging needs.

[0004] However, the rapid charging method described above causes significant polarization in lithium batteries, and prolonged use can easily lead to lithium deposition on the negative electrode of the lithium battery, affecting its lifespan. [Overview of the project] [Problems that the invention aims to solve]

[0005] The technical problem that this application aims to solve is that conventional charging methods cannot improve lithium deposition on the battery anode while guaranteeing rapid charging performance, and therefore, this invention provides a battery charging method, electronic equipment, and electrical equipment. [Means for solving the problem]

[0006] To solve the above problem, this invention is implemented by the following technical means.

[0007] This invention proposes a method for charging a battery, and this charging method is This includes charging the battery in fast charge cycle mode. The aforementioned rapid charging cycle mode includes steps S111 to S114, In S111, the battery is pre-charged at a first current value for a first time length T1, where 0s ≦ T1 ≦ 5s, and the first current value is 0.1C to 0.5C. In S112, after the battery is pre-charged, the battery is formally charged at a second current value for a second time length T2, where 0s < T2 ≦ 120s, and the second current value is 1C to 5C. In S113, after the battery is formally charged, the battery is pre-discharged at a third current value for a third time length T3, where 3s ≦ T3 ≦ 10s, and the third current value is 0.01C to 0.1C. In S114, after the battery is pre-discharged, if the voltage of the battery is lower than a predetermined end voltage for charging, steps S111 - S113 are continuously executed until the voltage of the battery reaches the predetermined end voltage for charging.

[0008] Furthermore, in the charging method, before pre-charging the battery at a first current value for a first time length T1, the charging method includes When the number of rapid charging cycles n for charging the battery in the rapid charging cycle mode is greater than the rapid charging cycle threshold N, a step of determining the lithium precipitation risk situation of the battery, When there is no lithium precipitation risk in the battery, a step of continuously executing the step of charging the battery in the rapid charging cycle mode, When there is a lithium precipitation risk in the battery, a step of switching to the low-speed charging cycle mode and charging the battery.

[0009] Furthermore, in the charging method, the step of determining the lithium precipitation risk situation of the battery includes When n - N is an integer multiple of m, a step of determining the lithium precipitation risk situation of the battery according to the historical discharge capacity of the battery is included, where m is the number of rapid charging cycles for determining the lithium precipitation risk situation of the battery adjacent twice, and here n > m.

[0010] Furthermore, in the charging method, the step of determining the lithium precipitation risk situation of the battery according to the historical discharge capacity of the battery includes According to the hysteretic discharge capacity of the aforementioned battery, the discharge capacity C after rapid charging in the nth nm cycle is determined. n-m and discharge capacity C after n cycles of rapid charging n The steps to determine, (C n-m -C n The steps include: calculating and obtaining the current capacity cycle rate K1 of the battery according to ) / m, The step of defining the current capacity cycle rate K1 of the battery as the reference capacity cycle rate K2 when it first becomes greater than 0, according to the hysteretic discharge capacity of the battery, The step includes determining the lithium deposition risk status of the battery according to the current capacity cycle rate K1 and the reference capacity cycle rate K2.

[0011] Furthermore, in the charging method, the step of determining the lithium deposition risk status of the battery according to the current capacity cycle change rate K1 and the reference capacity cycle change rate K2 is: When K1 > x * K2, it is determined that there is a risk of lithium deposition in the battery, where x = 1.01 to 1.05.

[0012] Furthermore, before charging the battery in rapid charging cycle mode, The process further includes updating the initial value of the second current value according to the current capacity cycle rate change K1 and the reference capacity cycle rate change K2, and updating it in one of the following ways: Method 1: In the case where K1 ≤ K2, the second current value Ib n =Ib n-m Update it like this, Method 2: In the case of K2 ≤ K1 ≤ xK2, the second current value Ib n Update it as =(1-K1)*Ib, Method 3: In the case where K1 ≥ xK2, the second current value Ib n Update it as =(1-K1)*Ib*γ, Here, Ib = α * C, K1 represents the current capacity cycle change rate, K2 represents the reference capacity cycle change rate, C represents the rated capacity, α represents the non-lithium precipitation coefficient, n represents the number of rapid charge cycles, and γ represents the attenuation coefficient.

[0013] Furthermore, in the charging method, the step of determining the lithium precipitation risk situation of the battery is as follows: After charging the battery in the low-speed charge cycle mode, when the next charge is required, it is further determined that there is no lithium precipitation risk in the battery by charging the battery in the rapid charge cycle mode.

[0014] Furthermore, the step of charging the battery in the low-speed charge cycle mode includes: the step of obtaining the state of charge value, attenuation coefficient, and rated capacity of the battery; the step of determining a low-speed charging current according to the state of charge value, the attenuation coefficient, and the rated capacity; and the step of charging the battery with the low-speed charging current.

[0015] Furthermore, the step of determining a low-speed charging current according to the state of charge value, the attenuation coefficient, and the rated capacity includes: the step of determining the actual charge interval to which the state of charge value belongs; the step of determining an actual low-speed charging coefficient corresponding to the actual charge interval according to a preset correspondence between the charge interval and the low-speed charging coefficient, where in the preset correspondence, the upper limit value of each charge interval has a negative correlation with the low-speed charging coefficient; and the step of determining the low-speed charging current according to the product of the actual low-speed charging coefficient, the attenuation coefficient, and the rated capacity.

[0016] Furthermore, when there is a lithium precipitation risk in the battery, the step of switching to the low-speed charge cycle mode and charging the battery includes: If the battery has a lithium deposition risk, the process includes updating the number of slow charging cycles M = M + a, and charging the battery M consecutive times in slow charging cycle mode, where a is the increase in the number of slow charging cycles after determining the lithium deposition risk status of the battery two adjacent times.

[0017] Furthermore, in the charging method, the rapid charging cycle mode is The step of reducing the second current value is further included before repeating the step of pre-charging the battery with a first current value for a first time length T1. Furthermore, the step of reducing the second current value includes a step of reducing the second current value by a range of 2 to 5%.

[0018] Furthermore, in the charging method, before pre-charging the battery with a first current value, The method further includes determining the first time length according to the charge state value of the battery, the step of determining the first time length includes determining that the first time length is greater than 0 when the charge state value is less than the charge state threshold, and determining that the first time length is 0 when the charge state value is greater than the charge state threshold.

[0019] Furthermore, before charging the battery in a fast-charging cycle mode, the method further includes the steps of obtaining a target fast-charging time length, determining the first current value and the second time length according to the target fast-charging time length, wherein both the first current value and the second time length are negatively correlated with the target fast-charging time length.

[0020] The present invention further proposes an electronic device comprising a processor, a communication interface, memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other via the communication bus, the memory is used to store a computer program, and when the computer program is executed by the processor, the electronic device performs the method of any one of the above.

[0021] The present invention further proposes an electrical device comprising a battery and a battery management system, wherein the battery management system is used to charge the battery in accordance with any one of the methods described in the above-mentioned paragraph.

[0022] In this invention, according to the battery charging method provided, when charging a battery in a rapid charging cycle mode, the battery is pre-charged at 0.1C to 0.5C for 0 to 5 seconds until the battery voltage reaches a predetermined termination voltage of charging, then formally charged at a second current value of 1C to 5C for 120 seconds or less, and then pre-discharged at a third current value of 0.01C to 0.1C for 3 to 10 seconds, alternating between these steps. By alternating between high-current and low-current charge / discharge cycles during a rapid charging cycle, the charging time is only slightly extended. This eliminates polarization caused by rapid charging at high currents, improves lithium deposition at the interface, prevents abnormal voltage drops in cells, and equalizes local differences in interface SOC caused by rapid charging. Meanwhile, low-current charging reduces variations in cell temperature rise, suppresses localized overcharging and over-discharging phenomena, and improves lithium deposition while simultaneously extending the effective life of the battery. Thus, this solves the problem that conventional charging methods could not solve while guaranteeing rapid charging performance and improving lithium deposition at the negative electrode of lithium batteries.

[0023] The above description is merely an overview of the technical means of the present application. To better understand the technical means of the present application, specific embodiments of the present application are described below, which can be implemented based on the specifications and which can be made clearer and easier to understand the above and other purposes, features, and advantages of the present application. [Brief explanation of the drawing]

[0024] To more clearly describe the embodiments of the present application or the technical means in the prior art, the drawings that may be used in the description of the embodiments or the prior art are briefly described below. Naturally, the drawings described below are some embodiments of the present application, and those skilled in the art will be able to conceive of other drawings based on these without requiring any creative effort. [Figure 1] This is a flowchart of the battery charging method provided in the embodiment of the present invention. [Figure 2] This is a block diagram of the electronic device provided in the embodiment of the present application. [Modes for carrying out the invention]

[0025] To clarify the purpose, technical means, and advantages of the embodiments of this application, the technical means will be described clearly and completely below with reference to the drawings relating to the embodiments of this application. Naturally, the embodiments described are only a part of the embodiments of this application, not all of them. All other embodiments obtained by a person skilled in the art without creative work based on the embodiments of this application are all within the scope of the protection of the present invention.

[0026] To make the above-mentioned objectives, features, and advantages of this application clearer and easier to understand, this application will be described in more detail with reference to the drawings and specific embodiments.

[0027] The applicant for this patent has discovered that while conventional rapid charging methods such as pulse charging, variable current charging, and variable voltage charging can significantly improve the battery charging rate and achieve a rapid charging effect, these charging methods, although they can shorten the rapid charging time, tend to cause large polarization phenomena and easily lead to lithium deposition at the interface, thus affecting the battery's cycle life.

[0028] In order to solve the above problems, embodiments of the present application provide a method for charging a battery. The battery is charged in a rapid charging cycle mode. As shown in FIG. 1, the rapid charging cycle mode includes steps S111 to step S114.

[0029] In step S111, the battery is pre-charged at a first current value for a first time length T1, where 0s ≦ T1 ≦ 5s, and the first current value is 0.1C to 0.5C.

[0030] In step S111 above, when starting and executing the rapid charging cycle mode, first, the battery is charged at a current value of 0.1C to 0.5C for 0 to 5s to complete one pre-charging process. The small current charging at 0.1C to 0.5C for 0 to 5s can reduce the variation of the cell temperature rise, suppress local overcharging and over-discharging phenomena while suppressing the increase in charging time, improve lithium precipitation, and at the same time improve the effective life of the battery. Here, C represents the rated capacity.

[0031] Optionally, in some embodiments, T1 may be in the range of 1s, 2s, 3s, 4s, 5s or any range between any two of these values.

[0032] Optionally, in some embodiments, the first current value may be in the range of 0.1C, 0.2C, 0.3C, 0.4C, 0.5C or any range between any two of these values.

[0033] In step S112, after the battery is pre-charged, the battery is formally charged at a second current value for a second time length T2, where 0s < T2 ≦ 120s, and the second current value is 1C to 5C.

[0034] In step S112 above, after the pre-charging is completed, the battery is formally charged at a current value of 1C to 5C for 120s or less to complete one formal charging process.

[0035] Here, the second time length is greater than the first time length. Optionally, in some embodiments, T2 may be in the range of 10s, 20s, 30s, 40s, 50s, 60s, 70s, 80s, 90s, 100s, 110s, 120s, or any two of these values.

[0036] Selectively, in some embodiments, the second current value may be in the range of 1C, 2C, 3C, 4C, 5C, or any two of these values.

[0037] In step S113, after the battery has been fully charged, the battery is pre-discharged for a third time period T3 at a third current value, where 3s ≤ T3 ≤ 10s, and the third current value is between 0.01C and 0.1C.

[0038] In step S113 described above, after completing one full charge cycle, the battery is pre-discharged at a current value of 0.01C to 0.1C for 3 to 10 seconds to complete one pre-discharge process, thereby eliminating polarization caused by rapid charging at high currents and improving the lithium deposition phenomenon at the interface.

[0039] Selectively, in some embodiments, T3 may be in the range between 3s, 4s, 5s, 6s, 7s, 8s, 9s, 10s or any two of these values.

[0040] Selectively, in some embodiments, the third current value may be in the range of 0.01C, 0.02C, 0.03C, 0.04C, 0.05C, 0.06C, 0.07C, 0.08C, 0.09C, 0.1C, or any two of these values.

[0041] In step S114, after pre-discharging the battery, if the battery voltage is lower than a predetermined termination voltage for charging, steps S111-S113 are continued until the battery voltage reaches the predetermined termination voltage for charging.

[0042] In step S114 described above, if the battery voltage is lower than a predetermined termination voltage for charging, it indicates that the battery is not yet fully charged and further charging is required. Therefore, the step of pre-charging the battery with a first current value for a first time length T1 is performed, i.e., steps S111 to S113 are continued until the battery voltage reaches a predetermined termination voltage for charging. This indicates that the battery is fully charged, and charging is stopped.

[0043] In the charging method provided in the embodiment of the present application, by alternating between high-current and low-current charge-discharge cycles during a rapid charging cycle, the charging time is only slightly extended to eliminate polarization caused by rapid charging at high current, improve lithium deposition at the interface, prevent abnormal voltage drops in the cell, and equalize local differences in interface SOC due to rapid charging. On the other hand, low-current charging reduces variations in cell temperature rise, suppresses localized overcharging and over-discharging phenomena, and improves lithium deposition while simultaneously extending the effective life of the battery. Thus, the conventional charging method has solved the problem of not being able to improve lithium deposition at the negative electrode of lithium batteries while guaranteeing rapid charging performance.

[0044] Furthermore, the charging method provided in the embodiment of this application controls the battery to be charged with the optimal time and charging current value, thereby guaranteeing the cycle performance of the cells, resulting in simpler operation and reduced optimization costs.

[0045] Selectively, in one embodiment, the charging method provided in the embodiment of the present application further includes steps S101 to S102 before charging the battery in a rapid charging cycle mode.

[0046] In step S101, the target fast charging time length is obtained.

[0047] In this step, the target rapid charging time is the charging time to fully charge the battery selected by the user using an external charging device. When the charging gun is inserted into the vehicle's charging port, the vehicle's battery management system becomes communicatively connected to the external charging device, allowing the target charging time to be obtained.

[0048] In step S102, the first current value and the second time length are determined according to the target rapid charging time length, where both the first current value and the second time length are negatively correlated with the target rapid charging time length.

[0049] In this step, the longer the target rapid charging time, the less energy needs to be charged into the battery per unit time, and the shorter the target rapid charging time, the more energy needs to be charged into the battery per unit time. Therefore, both the first current value and the second time length are set to have a negative correlation with the target rapid charging time. In other words, when the target rapid charging time is short, the battery is pre-charged with a larger current value, and when the target rapid charging time is long, the battery is pre-charged with a smaller current value. This allows for adapting to the user's rapid charging needs while minimizing the lithium deposition problem.

[0050] For example, if the target rapid charging times are 10, 20, 30, and 40 minutes, the first current value Ia can be set to 0.5C, 0.4C, 0.3C, and 0.2C to correspond to these values.

[0051] Selectively, in one embodiment, the rapid charging cycle mode provided in the embodiment of the present application is The step S115 further includes reducing the second current value before repeating the step of pre-charging the battery with a first current value for a first time length T1.

[0052] In this embodiment, the second current value in formal charging is reduced once each time a rapid charging cycle is performed, thereby adapting to the gradually increasing charge state value and more effectively mitigating the risk of lithium deposition.

[0053] Selectively, in one particular embodiment, the step of reducing the second current value specifically includes reducing the second current value by a range of 2 to 5%.

[0054] In this particular embodiment, the second current value in formal charging is reduced by a range of 2-5% each time a rapid charging cycle is performed.

[0055] Selectively, the drop in the second current value can be determined according to the target fast charging time, where the drop is negatively correlated with the target fast charging time. That is, when the target fast charging time is short, the second current value can be reduced by a larger drop, and when the target fast charging time is long, the second current value can be reduced by a smaller drop, thereby adapting to the user's fast charging needs while minimizing the lithium deposition problem.

[0056] For example, if the target rapid charging times are 10, 20, 30, and 40 minutes, the drop in the second current value can be set to 5%, 4%, 3%, and 2% to correspond to these values.

[0057] Selectively, in one embodiment, the rapid charging cycle mode provided in the embodiment of the present application pre-charges the battery with a first current value, The process further includes step S103, which determines the first time length according to the charge state value of the battery.

[0058] In this step, since the battery exhibits different charge rate performance at different charge states, a pre-charge time length that matches the actual charge performance of the battery can be set each time a rapid charging cycle is performed in order to equalize the charge rate performance at each charge state, i.e., the first time length can be determined.

[0059] In actual applications, the higher the charge state value, the smaller the current the battery can withstand without lithium deposition, meaning its rate performance decreases. The smaller the second current value, the smaller the difference between the first and second current values, and the less significant the effect of low-current charging in improving lithium deposition becomes. Therefore, the first time length can be set to have a negative correlation with the battery's charge state value, meaning that the higher the battery's charge state value, the shorter the first time length becomes.

[0060] Optionally, in one particular embodiment, step S103 includes the steps of determining that the first time length is greater than 0 if the charge state value is less than the charge state threshold, and determining that the first time length is 0 if the charge state value is greater than the charge state threshold.

[0061] In the specific embodiment described above, the charge state threshold is a charge state value that is likely to cause lithium deposition in the battery, requiring current-limited charging, and the charge state threshold must be set according to the actual performance of the battery, for example, 80%, 85%, or 90%.

[0062] In the specific embodiment described above, when the battery's charge state value is smaller than the charge state threshold, the second current value during formal charging is relatively large, so in order to more effectively mitigate the polarization phenomenon, it is necessary to pre-charge the battery first, i.e., to set the first time length to be greater than 0. When the battery's charge state value is greater than or equal to the charge state threshold, the second current value during formal charging is relatively small, so the polarization phenomenon due to formal charging is weakened, and it becomes unnecessary to pre-charge the battery further, i.e., the first time length can be set to 0, thereby improving the charging efficiency.

[0063] Exemplarily, when the state-of-charge value of the battery is 80% or less, it is set such that 0s < T2 ≤ 90s and 1s ≤ T1 ≤ 5s, and when the state-of-charge value of the battery becomes greater than 80%, it is set such that 90s < T2 ≤ 120s and T1 = 0s.

[0064] Optionally, in one embodiment, according to the charging method provided by the embodiments of the present application, before pre-charging the battery with a first current value, the method further includes steps S104 to step S106.

[0065] In step S104, when the number of rapid charge cycles n for charging the battery in the rapid charge cycle mode is greater than the rapid charge cycle threshold value N, the lithium precipitation risk situation of the battery is determined.

[0066] In this step, a rapid charge cycle threshold value N is set in advance. The rapid charge cycle threshold value is the number of rapid charge cycles that triggers the determination of the lithium precipitation risk situation of the battery. The rapid charge cycle threshold value N can be set according to the actual performance of the battery. For example, it can be set to 10 times. That is, when the number of times of charging the battery using the rapid charge cycle mode in the charging method provided by the embodiments of the present application reaches 10 times, it triggers the determination of the lithium precipitation risk situation of the battery. When the number of times of charging the battery using the rapid charge cycle mode in the charging method provided by the embodiments of the present application is less than 10 times, the step of determining the lithium precipitation risk situation of the battery is not executed.

[0067] In step S105, when there is no lithium precipitation risk in the battery, the step of charging the battery in the rapid charge cycle mode is continuously executed.

[0068] In this step, when it is determined that there is currently no lithium precipitation risk in the battery, it indicates that the battery state is good and rapid charging can be continued. Therefore, in order to meet the user's rapid charging needs, the step of charging the battery in the rapid charge cycle mode is continuously executed.

[0069] In step S106, if there is a risk of lithium deposition in the battery, the battery is charged by switching to a slow charging cycle mode.

[0070] In this step, if it is determined that the battery currently has a risk of lithium deposition, it indicates that the battery condition is poor and rapid charging cannot be continued. Therefore, in order to address the lithium deposition problem in the battery, the step of switching to a slow charging cycle mode and charging the battery is performed.

[0071] In the above embodiment, the determination of the lithium deposition risk status of the battery is triggered only when the number of times the battery is charged in the rapid charging cycle mode reaches the rapid charging cycle threshold N. If there is no lithium deposition risk in the battery, the battery continues to be charged in the rapid charging cycle mode; otherwise, the battery is set to be charged in the slow charging cycle mode. This allows for rapid mitigation of the battery's polarization state and improvement of the lithium deposition problem.

[0072] Selectively, in one embodiment, step S104 is specifically: If nN is an integer multiple of m, the procedure includes the step of determining the lithium deposition risk status of the battery according to the hysteretic discharge capacity of the battery, where m is the number of rapid charging cycles for which the lithium deposition risk status of the battery is determined two adjacent times, and where n > m.

[0073] In this embodiment, the hierarchical discharge capacity is the output capacity value after the battery has reached a fully charged state before the current charging begins. Here, since the hierarchical discharge capacity reflects the battery's capacity retention status and change trend, the lithium deposition risk status of the battery can be determined based on this hierarchical discharge capacity.

[0074] In this embodiment, after the number of times the battery has been charged in rapid charging cycle mode reaches N, and then when the number of times the battery has been charged in rapid charging cycle mode reaches m, a determination is made as to whether or not there is a risk of lithium deposition in the battery. This allows for the rapid elimination of the risk of lithium deposition if it exists in the battery.

[0075] Alternatively, in one specific embodiment, m can be set to 10 so as to reduce the number of determinations as much as possible while ensuring timely determination of the lithium precipitation risk and reducing the computational load.

[0076] Alternatively, in one specific embodiment, step S104 includes steps S1041 to S1045.

[0077] In S1041, according to the historical discharge capacity of the battery, the discharge capacity C n-m after rapid charging in the (n - m)th cycle and the discharge capacity C n after rapid charging in the nth cycle are determined.

[0078] In this step, since each output capacity value after the battery is fully charged according to the historical discharge capacity is recorded, before performing this charge, based on the historical discharge capacity, the discharge capacity C n after full charge in the most recent first (i.e., the previous) rapid charging mode and the discharge capacity C n-m after full charge in the most recent mth rapid charging mode can be obtained.

[0079] In S1042, the current capacity cycle change rate K1 of the battery is calculated and obtained according to (C n-m - C n ) / m.

[0080] In this step, the difference in the discharge capacity of the battery after two rapid chargings with m rapid chargings in between is divided by m to obtain the current capacity cycle change rate of the battery.

[0081] In S1043, according to the historical discharge capacity of the battery, when the current capacity cycle change rate K1 of the battery first becomes greater than 0, the capacity cycle change rate is defined as the reference capacity cycle change rate K2.

[0082] In S1044, the lithium deposition risk status of the battery is determined according to the current capacity cycle rate K1 and the reference capacity cycle rate K2.

[0083] In this step, the reference capacity cycle rate reflects the capacity change when the battery is charged in rapid charging cycle mode in its initial state, and the current capacity cycle rate reflects the capacity change when the battery is charged in rapid charging cycle mode in its current state. By comparing the reference capacity cycle rate with the current capacity cycle rate, it is possible to determine whether there is an abnormality in the battery's current capacity cycle rate, i.e., whether there is a risk of lithium deposition.

[0084] Selectively, in one particular embodiment, step S1045 above is specifically: In the case where K1 > x * K2, the step includes determining that there is a risk of lithium deposition in the battery, where x = 1.01 to 1.05.

[0085] In this particular embodiment, x is a determination coefficient, and its value is set within the range of 1.01 to 1.05 depending on the battery system and materials. Here, if K1 > x * K2, it indicates that the rate of change in capacity is increasing rapidly, and there is a high possibility that the battery has a high risk of lithium deposition, so it is determined that the battery has a risk of lithium deposition. If K1 ≤ x * K2, it indicates that the change in the rate of change in capacity is not significant, and the risk of lithium deposition in the battery is not clear, so it can be determined that the battery does not have a risk of lithium deposition.

[0086] Selectively, in one embodiment, step S104 is, The process further includes step S1046, which determines that there is no risk of lithium deposition in the battery, so that after charging the battery in a slow charging cycle mode, the next time charging is required, the battery will be charged in a fast charging cycle mode.

[0087] In this embodiment, charging the battery in a slow charging cycle mode effectively mitigates the polarization phenomenon of the battery and improves the risk of lithium deposition. Theoretically, after charging the battery in a slow charging cycle mode, the battery can withstand the polarization effect of the fast charging cycle mode. Therefore, when charging is needed again, it is determined that there is no risk of lithium deposition in the battery, and the battery should be charged in a fast charging cycle mode.

[0088] Selectively, in one embodiment, the step of charging the battery in a slow charging cycle mode includes steps S1061 to S1063.

[0089] In S1061, the charge state value, attenuation coefficient, and rated capacity of the battery are obtained.

[0090] In this step, the charge state value refers to the charge state value of the battery before charging in a slow charging cycle mode, which can be obtained directly from the battery management system, while the attenuation coefficient and rated capacity are fixed performance parameters of the battery and are related to the battery's structure and materials.

[0091] In S1062, the slow charging current is determined according to the charge state value, the attenuation coefficient, and the rated capacity.

[0092] In this step, since the charging current that can mitigate the polarization effect of the battery and improve the risk of lithium deposition is related to the battery's charge state value, decay coefficient, and rated capacity, a suitable slow charging current can be determined based on the battery's actual charge state value, decay coefficient, and rated capacity.

[0093] In step S1063, the battery is charged with the low-speed charging current.

[0094] In this step, the battery is charged with the low-speed charging current determined in step S1062 above.

[0095] In the above embodiment, if it is determined that there is a risk of lithium deposition in the battery, a suitable slow charging current is determined based on the battery's charge state value, decay coefficient, and rated capacity, and the battery is charged with this slow charging current until the voltage reaches a predetermined termination voltage for charging, thereby better mitigating polarization and improving the lithium deposition problem.

[0096] Selectively, in one particular embodiment, step S1062 includes steps S10621 to S10623.

[0097] In step S10621, the actual charge interval to which the charge state value belongs is determined.

[0098] In this step, the charge state values ​​of the battery are divided into multiple non-overlapping charge intervals in advance. After the actual charge state value of the battery is determined, the charge interval to which the charge state value belongs, i.e., the actual charge interval, can be determined according to the relationship between the charge state value and the upper and lower limits of each charge interval.

[0099] In step S10622, the actual slow charging coefficient corresponding to the actual charging section is determined according to a predetermined correspondence between the charging section and the slow charging coefficient, where, in the predetermined correspondence, the upper limit of each charging section is negatively correlated with the slow charging coefficient.

[0100] In this step, a suitable slow charging coefficient is set for each charging interval according to the specific performance of the battery. This slow charging coefficient is greater than 0 but less than or equal to 1. Here, as the battery's charge level increases, the lithium deposition current it can withstand decreases. Therefore, as the charge level approaches saturation, the charging current must be gradually reduced. In other words, the upper limit of each charging interval is set to have a negative correlation with the slow charging coefficient.

[0101] In step S10623, the slow charging current is determined according to the product of the actual slow charging coefficient, the attenuation coefficient, and the rated capacity.

[0102] In this step, the actual slow charging coefficient is multiplied by the attenuation coefficient and the rated capacity to calculate and obtain a suitable slow charging current value.

[0103] Illustratively, step S1062 specifically includes the steps of: determining the slow charging current to γC when the charge state value is in the range of 5% to 50%; determining the slow charging current to 0.5γC when the charge state value is in the range of 50% to 85%; and determining the slow charging current to 0.2γC when the charge state value is in the range of 85% to 97%, where γ = C n / C1, where C represents the rated capacity and γ represents the damping coefficient. n This represents the discharge capacity after the last full charge in rapid charging mode. In other words, when the battery is charged by triggering the slow charging cycle mode, it is charged with a current of γC when the battery's charge level is in the range of 5% to 50%, with a current of 0.5γC when the battery's charge level is in the range of 50% to 85%, and with a current of 0.2γC when the battery's charge level is in the range of 85% to 97%.

[0104] In the above embodiment, if it is determined that there is a risk of lithium deposition in the battery, an appropriate actual slow charging coefficient is determined based on the battery's charge state value. Then, an appropriate slow charging current is determined based on the actual slow charging coefficient, decay coefficient, and rated capacity. The battery is then charged with this slow charging current until the voltage reaches a predetermined termination voltage for charging. This better mitigates polarization and improves the lithium deposition problem.

[0105] Selectively, in one particular embodiment, step S106 specifically includes the step of charging the battery M consecutive times in slow charging cycle mode, updating the number of slow charging cycles M = M + a if there is a lithium deposition risk in the battery, where a is the increase in the number of slow charging cycles after two consecutive determinations of the lithium deposition risk status of the battery. In this particular embodiment, the initial value of M is 0, and the continuous occurrence of lithium deposition risk indicates that the health of the lithium battery is continuously deteriorating. By setting the number of slow charging cycle modes performed after it is determined that the battery is at risk of lithium deposition to gradually increase in step a, the lithium deposition risk that gradually deteriorates due to rapid charging can be effectively addressed. Here, a may be 1, 2, or 3, etc.

[0106] Selectively, the M value is set to 10 or less. Here, because the need for slow charging is decreasing during actual application, the number of slow charging cycles in each cycle is controlled to be within 10 cycles, that is, alternating between performing one slow charging cycle every 10 fast charging cycles, and so on, until alternating between performing 10 slow charging cycles every 10 fast charging cycles.

[0107] Selectively, in one embodiment, the charging method provided by the embodiment of the present application, before charging the battery in a rapid charging cycle mode, The step S107 further includes updating the initial value of the second current value according to the current capacity cycle rate change K1 and the reference capacity cycle rate change K2.

[0108] In this step, before starting to charge the battery in rapid charging cycle mode, first, based on the current capacity cycle rate and reference capacity cycle rate of the battery, the initial formal charging current, i.e., the initial value of the second current value described above, which is suitable for the current lithium deposition state of the battery, is determined.

[0109] Selectively, in one particular embodiment, step S107 above is updated in one of the following ways: Method 1: In the case where K1 ≤ K2, the second current value Ib n =Ib n-m Update it like this, Method 2: In the case of K2 ≤ K1 ≤ xK2, the second current value Ib n Update it as =(1-K1)*Ib, Method 3: In the case where K1 ≥ xK2, the second current value Ib n Update it as =(1-K1)*Ib*γ, Here, Ib = α * C, where K1 represents the current capacity cycle rate, K2 represents the reference capacity cycle rate, C represents the rated capacity, α represents the non-lithium deposition coefficient, n represents the number of fast-charging cycles, γ represents the decay coefficient, and x = 1.01 to 1.05.

[0110] In the specific embodiment described above, Ib ≤ Imax, where Imax is the maximum non-lithium deposition current of the battery cell in a particular charging interval, and the non-lithium deposition coefficient α is obtained by Imax / C.

[0111] Embodiments of the present invention further provide an electrical device comprising a battery and a battery management system, wherein the battery management system is used to charge the battery in accordance with the method described above.

[0112] Since the above embodiment of the electrical device is almost the same as the embodiment of the battery charging method, the relevant parts should be referred to in the description of the embodiment of the method.

[0113] The present application will be described in detail below using examples.

[0114] Example 1

[0115] (1) Manufacturing of positive electrode plates Li(Ni0.8Mn0.1Co0.1)O2(NMC811), a positive electrode active material, acetylene black (Super P), a conductive agent, and polyvinylidene fluoride (PVDF), a binder, were uniformly mixed in a mass ratio of 94:3:3. A uniform black slurry was then uniformly dispersed in 1-methyl-2-pyrrolidone (NMP). The prepared slurry was applied to both sides of an aluminum foil, and then fired, rolled, and cut to obtain a positive electrode plate.

[0116] (2) Manufacturing of the negative electrode plate A uniform black slurry is prepared by uniformly mixing artificial graphite (Ag), silicon monoxide (SiO), a negative electrode active material, acetylene black (Super P), a conductive agent, and SBR, a binder, in a mass ratio of 84.6:9.4:3:3, and then uniformly dispersing them in deionized water. The prepared slurry is then applied to both sides of aluminum foil, followed by firing, rolling, and cutting to achieve a surface density of 7 mg / cm². 2 A negative electrode plate was obtained.

[0117] (3) Manufacturing of electrolyte Ethylene carbonate (EC), methyl ethyl carbonate (EMC), and diethyl carbonate (DEC) are uniformly mixed in a mass ratio of 30:30:40 to obtain a mixed solvent. Next, lithium salt LiPF6, or lithium salt LiPF6 and an additive, is dissolved in the obtained mixed solvent and uniformly mixed to obtain an electrolyte. In this electrolyte, the LiPF6 concentration is 1 mol / L, and the LiODFB mass percentage content is 0.3%.

[0118] (4) Manufacturing of secondary batteries The manufactured positive electrode plate, separator, and negative electrode plate are stacked in order, with the separator placed between the positive and negative electrode plates. A jelly roll structure is obtained through winding, hot-press molding, and tab welding. The jelly roll structure is then sealed in an outer aluminum plastic film and dried for 24 hours in a drying oven at 85±10℃. The prepared electrolyte is injected into the dried battery, and after standing, chemical conversion, and capacity sorting, the manufacturing of the lithium-ion soft pack battery is completed.

[0119] Charge the battery at 25℃ by following these steps: (1) The charge is performed with a constant current Ia = 0.3C, and the charging time is 1 s. (2) The charge is performed with a constant current Ib = 1C, and the charging time is 10s. (3) Discharge at a constant current of 0.01C, with a discharge time of 3s. (4) Repeat steps (1) to (3) until the battery voltage reaches the upper limit of the termination voltage and complete the cycle.

[0120] For other examples and comparative examples, please refer to Example 1, and the differences are shown in Table 1. The secondary batteries manufactured in the examples and comparative examples were tested using the Shin'i Battery Test System, and the lowest lithium deposition potential of the negative electrode under different test conditions for the same battery was obtained and recorded in Table 1. The secondary batteries manufactured in the examples and comparative examples were tested using the Shin'ei Battery Test System, and the battery cycle retention rate after 500 cycles of the same battery was obtained and recorded in Table 1.

[0121] [Table 1]

[0122] From the test results in Table 1, it can be seen that Comparative Example 1 had the best retention rate after 500 cycles and the lithium deposition potential of the negative electrode was optimal, but the overall cycle period was long, making it unsuitable for application. Comparative Examples 2, 3, and 4 had low lithium deposition potentials on the negative electrode and poor battery retention rates after 500 cycles, indicating poor performance of the rapid charging process during cycles. In the other examples, the cycle retention rate was higher than that of the comparative examples, indicating that the rapid charging method, which alternates between low and high current charging and discharging, significantly improved cycle performance and achieved a high cycle retention rate.

[0123] Embodiments of the present invention further provide an electronic device, as shown in Figure 2, comprising a processor 201, a communication interface 202, a memory 203, and a communication bus 204, wherein the processor 201, the communication interface 202, and the memory 203 communicate with each other via the communication bus 204. Memory 203 is used to store computer programs. When processor 201 executes a program stored in memory 203, It is used to implement the step of charging the battery in fast charge cycle mode. The aforementioned rapid charging cycle mode is: A step of pre-charging the battery at a first current value for a first time length T1, where 0s ≦ T1 ≦ 5s and the first current value is 0.1C to 0.5C, and After pre-charging the battery, a step of formally charging the battery at a second current value for a second time length T2, where 0s < T2 ≦ 120s and the second current value is 1C to 5C, and After formally charging the battery, a step of pre-discharging the battery at a third current value for a third time length T3, where 3s ≦ T3 ≦ 10s and the third current value is 0.01C to 0.1C, and After pre-discharging the battery, if the voltage of the battery is lower than a predetermined end voltage for charging, a step of continuously executing the step of pre-charging the battery at the first current value for the first time length T1. It includes

[0124] Here, the processor 201 can also implement other steps in the above battery charging method, which will not be repeatedly described here.

[0125] Examples of the communication bus mentioned with respect to the above electronic device include a Peripheral Component Interconnect (PCI for short) bus or an Extended Industry Standard Architecture (EISA for short) bus. The communication bus can be classified into an address bus, a data bus, a control bus, etc. For ease of illustration, it is represented by a single thick line in the drawings, but it does not mean that there is only one bus or one type of bus.

[0126] The communication interface is used for communication between the above electronic device and other devices.

[0127] Memory may include random access memory (RAM), and may also include non-volatile memory, such as at least one disk memory. Optionally, memory may also be at least one storage device located away from the aforementioned processor.

[0128] The above-mentioned processor may be a general-purpose processor including a Central Processing Unit (CPU), a Network Processor (NP), or it may be a Digital Signal Processing (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA), or other programmable logic device, discrete gate or transistor logic device, or discrete hardware component.

[0129] In another embodiment provided herein, a computer-readable storage medium is further provided. Instructions are stored in the computer-readable storage medium, and when executed on a computer, the instructions cause the computer to perform the battery charging method described in the embodiment.

[0130] In another embodiment provided herein, a computer program product including instructions is further provided, which, when executed on a computer, causes the computer to perform the battery charging method described in the embodiment.

[0131] Another embodiment provided in the present application further provides an electrical device comprising a battery and a battery management system, wherein the battery management system comprises the electronic device described in the above embodiment.

[0132] In the embodiments described above, all or part of the embodiments may be implemented by software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the flow or functionality described in the embodiments of the present application is generated. The computer may be a general-purpose computer, a dedicated computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer instructions may be transferred from one website, computer, server, or data center to another website, computer, server, or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, radio, microwave, etc.). The computer-readable storage medium may be any available medium accessible to the computer, or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid state disks (SSDs)).

[0133] In this specification, relational terms such as "First," "Second," etc., are used merely to distinguish one entity or operation from another entity or operation, and do not require or suggest that such an actual relationship or order exists between these entities or operations. Furthermore, "includes," "contains," or variations thereof are intended to be non-exclusive, meaning that a process, method, article, or apparatus containing a set of elements includes not only those elements but also other elements not explicitly listed, or elements specific to that process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "includes one..." does not preclude the existence of another identical element in a process, method, article, or apparatus containing that element.

[0134] Each embodiment in this specification is described in relation to others, and parts that are identical or similar between embodiments should be cross-referenced. Each embodiment focuses on the differences from the other embodiments. Embodiments of electrical equipment, electronic equipment, computer-readable storage media, and computer program products including instructions are basically similar to the embodiments of the methods, and therefore the descriptions are relatively simplified; relevant parts should be referred to the descriptions of the embodiments of the methods.

[0135] The foregoing describes only preferred embodiments of the present application and does not limit the scope of protection. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present application shall be included within the scope of protection.

[0136] As described above, in this embodiment, by alternating between high-current and low-current charge / discharge cycles during a rapid charging cycle, polarization caused by rapid charging at high currents can be eliminated, lithium deposition at the interface can be improved, abnormal voltage drops in the cell can be prevented, and local differences in interface SOC due to rapid charging can be made uniform. On the other hand, low-current charging reduces variations in cell temperature rise, suppresses localized overcharging and over-discharging phenomena, and improves lithium deposition while simultaneously improving the effective life of the battery. Thus, this solves the problem that conventional charging methods could not improve lithium deposition at the negative electrode of lithium batteries while guaranteeing rapid charging performance.

[0137] While preferred embodiments of the embodiments of this application have been described, those skilled in the art, knowing the basic creative concepts, can make other changes and modifications to these embodiments. Accordingly, the claims described herein are construed to include all changes and modifications that fall within the scope of the preferred embodiments and embodiments of this application.

[0138] The above has provided a detailed description of the battery charging method and electrical equipment provided in this application. While this specification has used specific examples to illustrate the principles and embodiments of this application, the above description of embodiments is intended to aid in understanding the method and core concept of this application. At the same time, those skilled in the art can modify the specific embodiments and scope of application based on the concept of this application. Therefore, the contents of this specification should not be construed as limitations on this application. [Cross-reference of related applications]

[0139] This application claims priority to the patent application filed with the China National Patent Office on July 21, 2023, with application number 202310911922.7, and the title of the invention being "Method for charging a battery and electrical apparatus," the entire contents of which are incorporated into this application by reference.

Claims

1. The method for charging batteries, This includes a step of charging the battery in fast charge cycle mode, The aforementioned rapid charging cycle mode includes the following steps S111 to S114: In S111, the battery is pre-charged with a first current value for a first time period T1, where 0s ≤ T1 ≤ 5s, and the first current value is between 0.1C and 0.5C. In S112, after pre-charging the battery, the battery is formally charged with a second current value for a second time period T2, where 0s < T2 ≤ 120s, and the second current value is between 1C and 5C. In S113, after the battery has been fully charged, the battery is pre-discharged for a third time period T3 at a third current value, where 3s ≤ T3 ≤ 10s, and the third current value is between 0.01C and 0.1C. In step S114, if the battery has been pre-discharged and the voltage of the battery is lower than a predetermined termination voltage for charging, steps S111 to S113 are continued until the voltage of the battery reaches the predetermined termination voltage for charging.

2. Before pre-charging the battery with a first current value for a first time length T1, the method is as follows: If the number of rapid charging cycles n for the battery is greater than the rapid charging cycle threshold N, the lithium deposition risk status of the battery is determined: If there is no risk of lithium deposition in the battery, the step of continuing to charge the battery in rapid charging cycle mode is performed. The charging method according to claim 1, further comprising the step of switching to a slow charging cycle mode to charge the battery if there is a risk of lithium deposition in the battery.

3. The step of determining the lithium deposition risk status of the aforementioned battery is: The charging method according to claim 2, wherein n - N is an integer multiple of m, and includes the step of determining the lithium deposition risk status of the battery according to the hysteretic discharge capacity of the battery, where m is the number of rapid charging cycles for which the lithium deposition risk status of the battery is determined two adjacent times, and where n > m.

4. The step of determining the lithium deposition risk status of the battery according to the hysteretic discharge capacity of the battery is: According to the hysteretic discharge capacity of the aforementioned battery, the discharge capacity C after rapid charging in the n-m cycle is determined. ｎ－ｍ and discharge capacity C after n cycles of rapid charging ｎ The steps to determine, (C ｎ－ｍ -C ｎ The steps include: calculating and obtaining the current capacity cycle rate K1 of the battery according to ) / m, The step of defining the current capacity cycle rate K1 of the battery as the reference capacity cycle rate K2 when it first becomes greater than 0 according to the hysteretic discharge capacity of the battery, The charging method according to claim 3, comprising the step of determining the lithium deposition risk status of the battery according to the current capacity cycle rate K1 and the reference capacity cycle rate K2.

5. The step of determining the lithium deposition risk status of the battery according to the current capacity cycle rate K1 and the reference capacity cycle rate K2 is as follows: The charging method according to claim 4, which includes the step of determining that there is a risk of lithium deposition in the battery when K1 > x * K2, where x = 1.01 to 1.

05.

6. Before charging the aforementioned battery in rapid charging cycle mode, The process further includes updating the initial value of the second current value according to the current capacity cycle rate change K1 and the reference capacity cycle rate change K2, and updating it in one of the following ways: Method 1: When K1 ≤ K2, the second current value Ib ｎ = Ib ｎ－ｍ Update it like this, Method 2: In the case where K2 ≤ K1 ≤ x K2, the second current value Ib ｎ Update it as = (1 - K1) * Ib, Method 3: When K1 ≥ xK2, the second current value Ib ｎ The update is as follows: = (1-K1)*Ib*γ The charging method according to claim 5, where Ib = α * C, K1 represents the current capacity cycle rate change, K2 represents the reference capacity cycle rate change, C represents the rated capacity, α represents the non-lithium deposition coefficient, n represents the number of rapid charging cycles, and γ represents the decay coefficient.

7. The step of determining the lithium deposition risk status of the aforementioned battery is: The charging method according to claim 3, further comprising determining that there is no risk of lithium deposition in the battery, such that after charging the battery in a slow charging cycle mode, the battery is charged in a fast charging cycle mode the next time charging is required.

8. The step of charging the aforementioned battery in a slow charging cycle mode is: The steps include obtaining the charge state value, attenuation coefficient, and rated capacity of the aforementioned battery, The steps include determining a slow charging current according to the charge state value, the decay coefficient, and the rated capacity, The charging method according to claim 2, comprising the step of charging the battery with the low-speed charging current.

9. The step of determining the slow charging current according to the charge state value, the decay coefficient, and the rated capacity is: The steps include determining the actual charge interval to which the aforementioned charge state value belongs, A step of determining the actual slow charging coefficient corresponding to the actual charging section according to a predetermined correspondence between the charging section and the slow charging coefficient, wherein, in the predetermined correspondence, the upper limit of each charging section is negatively correlated with the slow charging coefficient. The charging method according to claim 8, comprising the step of determining the slow charging current according to the product of the actual slow charging coefficient, the decay coefficient, and the rated capacity.

10. If the battery has a risk of lithium deposition, the step of switching to a slow charging cycle mode to charge the battery is: The charging method according to claim 2, wherein if the battery has a lithium deposition risk, the charging method includes the step of updating the number of slow charging cycles M = M + a and charging the battery M consecutive times in slow charging cycle mode, where a is the increase in the number of slow charging cycles after determining the lithium deposition risk status of the battery two adjacent times.

11. The aforementioned rapid charging cycle mode is: The charging method according to claim 1, further comprising the step of reducing the second current value before repeating the step of pre-charging the battery with a first current value for a first time length T1.

12. The charging method according to claim 11, wherein the step of reducing the second current value includes reducing the second current value by a range of 2 to 5%.

13. Before pre-charging the aforementioned battery with a first current value, The process further includes the step of determining the first time length according to the charge state value of the battery, The step of determining the first time length is: The step of determining that the first hour length is greater than 0 when the charge state value is less than the charge state threshold, A charging method according to claim 1, comprising the step of determining that the first time length is 0 when the charge state value is greater than the charge state threshold.

14. Before charging the battery in fast charge cycle mode, Steps to obtain the target fast charging time length, The charging method according to claim 1, further comprising the step of determining the first current value and the second time length according to the target rapid charging time length, wherein both the first current value and the second time length are negatively correlated with the target rapid charging time length.

15. An electronic device comprising a processor, a communication interface, memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other via the communication bus. The aforementioned memory is used to store computer programs. When the computer program is executed by the processor, the electronic device performs the method according to any one of claims 1 to 14.

16. An electrical device comprising a battery and a battery management system, wherein the battery management system is used to charge the battery according to the method described in any one of claims 1 to 14.

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