Battery charging method, system, vehicle and medium based on lithium deposition detection

Abstract

A battery charging method, system, vehicle, and medium based on lithium deposition detection, which relate to the technical field of battery charging, are provided. The method includes the steps of: obtaining a battery charging policy table after receiving a battery charging command (S10); charging the battery based on a charging current in the battery charging policy table, and performing charging lithium deposition detection on the battery at least once during the battery charging process to obtain a first lithium deposition detection result (S20); if the first lithium deposition detection result indicates no lithium deposition has occurred, continuing to charge the battery based on the charging current and continue to perform charging lithium deposition detection on the battery until the first lithium deposition detection result indicates lithium deposition has occurred or until charging of the battery is completed (S30); and if the first lithium deposition detection result indicates lithium deposition has occurred, updating the charging current in the battery charging policy table based on a predetermined first current reduction policy, and continuing to charge the battery based on the updated charging current until charging is completed (S40).

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This disclosure claims priority to a Chinese patent application filed on September 27, 2020, bearing application number 202011032994.7 and entitled "Battery Charging Method, System, Vehicle and Medium Based on Lithium Deposition Detection," the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to the technical field of battery charging, and in particular to a battery charging method, system, vehicle and medium based on lithium deposition detection. [Background technology]

[0003] With the development of science and technology, the development of new energy vehicles is becoming more and more rapid. Because the battery is an important component of new energy vehicles, users have higher and higher requirements for the battery charging time of their vehicles. Further shortening the battery charging time can effectively improve the user's usage experience.

[0004] In the related art, the charging waveform is mainly optimized and the model combination control method is used to realize the rapid charging of the battery. The charging waveform optimization control method includes the optimization of the constant current constant voltage charging method, the stepwise charging method, the pulse charging method, and the AC charging method, but this method is an offline method for a new battery immediately after shipment, and does not fully consider the actual changes in the actual use process of the battery, which causes the safety of the battery to be deteriorated. The model combination control method includes the equivalent circuit model combination, the thermal model combination, the electrochemical model combination, and the combination model combination of the above models, and realizes the rapid charging of the battery by the above models, but this method has the disadvantage that the aging difference in the battery use process is large, it is difficult to accurately use a unified model to rapidly charge the battery, and the cost of using the model method is high. Summary of the Invention [Problem to be solved by the invention]

[0005] The embodiments of the present disclosure provide a battery charging method, system, vehicle, and medium based on lithium precipitation detection that realizes rapid charging of a battery and improves charging safety. [Means for solving the problem]

[0006] In a first aspect, a method for charging a battery based on lithium precipitation detection according to the present disclosure includes: obtaining a battery charging policy table after receiving a battery charging command; Charging the battery according to the charging current in the battery charging policy table, and during the charging process of the battery, performing charging lithium deposition detection on the battery at least once to obtain a first lithium deposition detection result; When the first lithium deposition detection result indicates that lithium deposition has not occurred, continuing to charge the battery based on the charging current and continuing to perform charging lithium deposition detection on the battery during the charging process of the battery, and stopping charging lithium deposition detection on the battery until the first lithium deposition detection result indicates that lithium deposition has occurred or until charging of the battery is completed; When the first lithium deposition detection result indicates that a lithium deposition phenomenon is occurring, the charging current in the battery charging policy table is updated based on a predetermined first current reduction policy, and the battery is continued to be charged based on the updated charging current until charging of the battery is completed.

[0007] In a second aspect, a battery charging system based on lithium deposition detection according to the present disclosure includes: a charging policy table acquisition module for acquiring a battery charging policy table after receiving a battery charging command; a charging lithium deposition detection module for charging a battery according to a charging current in the battery charging policy table, and performing charging lithium deposition detection on the battery at least once during the charging process of the battery to obtain a first lithium deposition detection result; a first charging module that, when the first lithium deposition detection result indicates that no lithium deposition phenomenon has occurred, continues to charge the battery based on the charging current until charging of the battery is completed, and continues to perform charging lithium deposition detection on the battery during the charging process of the battery; and a second charging module that, when the first lithium deposition detection result indicates that a lithium deposition phenomenon is occurring, updates the charging current in the battery charging policy table based on a predetermined first current reduction policy, and continues charging the battery based on the updated charging current until charging of the battery is completed.

[0008] In a third aspect, a vehicle according to the present disclosure includes a battery charging system based on lithium deposition detection as described above.

[0009] In a fourth aspect, a computer-readable storage medium according to the present disclosure stores a computer program that, when executed by a processor, realizes the battery charging method based on lithium deposition detection described above.

[0010] In the above-mentioned battery charging method, system, and automobile based on lithium deposition detection, the method includes the steps of: after receiving a battery charging command, obtaining a battery charging policy table; charging the battery based on the charging current in the battery charging policy table, and performing charging lithium deposition detection on the battery at least once during the charging process of the battery to obtain a first lithium deposition detection result; if the first lithium deposition detection result indicates that lithium deposition has not occurred, continuing to charge the battery based on the charging current, and continuing to perform charging lithium deposition detection on the battery during the charging process of the battery, and stopping charging lithium deposition detection on the battery until the first lithium deposition detection result indicates that lithium deposition has occurred or until charging of the battery is completed; if the first lithium deposition detection result indicates that lithium deposition has occurred, updating the charging current in the battery charging policy table based on a predetermined first current reduction policy, and continuing to charge the battery based on the updated charging current until charging of the battery is completed. Effect of the Invention

[0011] The present disclosure detects whether lithium deposition occurs in a battery during the charging process of the battery, and reduces the current charging current of the battery according to a first predetermined current reduction policy when lithium deposition occurs in the battery, thereby improving the safety during the charging process of the battery and fully ensuring the fast charging characteristics of the battery. The method in this embodiment can be applied to different types of batteries, and only needs to adjust the charging current in the battery charging policy table of the different types of batteries according to the first lithium deposition detection result, and the calculation amount related to the method is small, which reduces the calculation complexity of the system and improves the execution speed of the system. [Brief description of the drawings]

[0012] In order to more clearly describe the technical means of the embodiments of the present disclosure, the drawings necessary for describing the embodiments of the present disclosure will be briefly described below. Obviously, the drawings described below are only some embodiments of the present disclosure, and those skilled in the art can obtain other drawings based on these drawings without any creative work.

[0013] [Figure 1] 1 is a flowchart of a battery charging method based on lithium deposition detection in one embodiment of the present disclosure. [Diagram 2] 4 is another flowchart of a battery charging method based on lithium deposition detection in one embodiment of the present disclosure. [Diagram 3] FIG. 2 is a schematic diagram of a voltage-time coordinate system of a battery charging method based on lithium deposition detection in one embodiment of the present disclosure. [Figure 4] 1 is a flowchart of step S20 of a battery charging method based on lithium precipitation detection in one embodiment of the present disclosure. [Diagram 5] FIG. 1 is a block diagram showing the principle of a battery charging system based on lithium precipitation detection in one embodiment of the present disclosure. [Figure 6] FIG. 2 is another principle block diagram of a battery charging system based on lithium deposition detection in one embodiment of the present disclosure. [Figure 7] FIG. 1 is a schematic diagram of a computing device according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, the technical means in the embodiments of the present disclosure will be described clearly and completely with reference to the drawings in the embodiments of the present disclosure, and it is obvious that the described embodiments are only a part of the embodiments of the present disclosure, and are not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present disclosure without creative labor are all within the scope of protection of the present disclosure.

[0015] As shown in FIG. 1, a battery charging method based on lithium precipitation detection according to one embodiment includes the following steps S10 to S40.

[0016] In S10, after receiving a battery charging command, the battery charging policy table is obtained.

[0017] The battery charging command instructs to start charging the power battery pack at this time, for example, a user finds that the current SOC (State Of Charge) value of the power battery pack is too low, and charges the vehicle at a charging station at this time, and a battery charging command is generated at the time of starting charging. The battery charging policy table includes data related to battery charging, such as charging current, charging voltage, etc., and the battery charging policy table is obtained according to a quick charging policy created when the battery is shipped, and it can be understood that the charging current in the battery charging policy table may be updated and adjusted according to whether or not lithium deposition occurs in the battery during the charging process and / or after charging is completed. The lithium deposition phenomenon refers to the deposition of metallic lithium on the negative electrode of the battery.

[0018] In S20, the battery is charged based on the charging current in the battery charging policy table, and during the charging process of the battery, charging lithium deposition detection is performed on the battery at least once to obtain a first lithium deposition detection result.

[0019] The charging lithium deposition detection refers to a process of detecting the lithium deposition phenomenon in a battery during the charging process of the battery, and the charging lithium deposition detection includes, but is not limited to, a three-electrode direct measurement method, a Coulombic efficiency measurement method, and an electrochemical impedance measurement method. The first lithium deposition detection result is obtained after the charging lithium deposition detection is performed on the battery during the charging process of the battery, and the first lithium deposition detection result includes a result in which the lithium deposition phenomenon occurs in the battery and a result in which the lithium deposition phenomenon does not occur in the battery.

[0020] Specifically, after receiving a battery charging command, obtain a battery charging policy table, charge the battery according to the charging current in the battery charging policy table, and perform charging lithium deposition detection on the battery at least once during the charging process of the battery to obtain a first lithium deposition detection result to determine whether lithium deposition exists in the battery during the charging process. When lithium deposition occurs in the battery during the charging process, the charging current of the battery in the current charging process should be reduced to suppress lithium deposition and reduce the lithium deposition characteristic amount in the subsequent charging process. If lithium deposition does not occur in the battery during the charging process, continue to charge the battery with the charging current in the current charging process, and continue to perform charging lithium deposition detection on the battery in the subsequent charging process until the charging of the battery is completed.

[0021] In S30, if the first lithium deposition detection result indicates that lithium deposition has not occurred, the battery is continuously charged based on the charging current, and during the charging process of the battery, charging lithium deposition detection is continuously performed on the battery, and the first lithium deposition detection result indicates that lithium deposition has occurred. When it becomes Or, charging of the battery is completed. When Then, the detection of lithium deposition during charging of the battery is stopped.

[0022] Specifically, after charging the battery based on the charging current in the battery charging policy table, and performing charging lithium deposition detection on the battery during the charging process of the battery to obtain a first lithium deposition detection result, if the first lithium deposition detection result indicates that lithium deposition has not occurred, continue charging the battery based on the charging current in the battery charging policy table, and continue performing charging lithium deposition detection on the battery during the charging process of the battery. If the first lithium deposition detection result obtained at any subsequent time indicates that lithium deposition has occurred, stop charging lithium deposition detection on the battery, update the charging current in the battery charging policy table based on a predetermined first current reduction policy, and continue charging the battery based on the updated charging current until charging of the battery is completed. If the first lithium deposition detection result obtained by performing charging lithium deposition detection on the battery subsequently indicates that lithium deposition has not occurred, declare that there is no need to update the charging current in the battery charging policy table, and stop charging lithium deposition detection on the battery after charging of the battery is completed.

[0023] In S40, if the first lithium deposition detection result indicates that lithium deposition has occurred, the charging current in the battery charging policy table is updated based on a predetermined first current reduction policy, and the battery continues to be charged based on the updated charging current until charging of the battery is completed.

[0024] The predetermined first current reduction policy refers to a policy that reduces the current charging current at a predetermined rate, and for example, the first current reduction policy may be to reduce the charging current of the battery in the current charging process at a predetermined rate, and the predetermined rate may be 0.1% to 1% of the current charging current, for example, 0.5% of the current charging current, and thus, when the charging current is 1 A, the charging current can be reduced by 0.5%, that is, the charging current can be reduced to 0.995 A. As can be seen, whether the charging of the battery is completed can be determined according to the situation, for example, when the current SOC value of the battery reaches a predetermined SOC value, it can be determined that the charging of the battery is completed, and in other cases, the power off process can be performed ahead of schedule, for example, when the battery cannot continue to be charged due to a sudden power outage or charging is terminated ahead of schedule due to an artificial operation (for example, unplugging the charging plug from the charging station), it can be considered that the charging of the battery is already completed at this time.

[0025] Specifically, the battery is charged based on the charging current in the battery charging policy table, and during the charging process of the battery, a charging lithium deposition detection is performed on the battery to obtain a first lithium deposition detection result. If the first lithium deposition detection result indicates that a lithium deposition phenomenon has occurred, the charging current of the battery in the current charging process is reduced based on a predetermined first current reduction policy (when a lithium deposition phenomenon occurs in the battery, the lithium potential of the negative electrode of the battery drops to or below 0V, and if the battery is still charged with the current charging current, the lithium potential of the negative electrode of the battery will become smaller due to the polarization phenomenon during the charging process). The battery charging policy table is updated with the reduced charging current, and the battery is continuously charged until charging is completed based on the charging current in the updated battery charging policy table (i.e., the reduced charging current), thereby reducing the probability that the lithium deposition characteristic value of the battery will increase in the subsequent charging process, and further ensuring the safety of the battery charging process, i.e., if it is detected that the lithium deposition phenomenon has occurred once in the battery during the charging process, it is indicated that there is no need to continue to perform charging lithium deposition detection on the battery.

[0026] In this embodiment, whether lithium deposition occurs in the battery during the charging process of the battery is detected, and when lithium deposition occurs in the battery, the current charging current of the battery is reduced according to a predetermined first current reduction policy, thereby improving the safety of the battery during the charging process and ensuring that the battery exhibits fast charging characteristics under the premise of safety. In addition, the method in this embodiment can be applied to different types of lithium batteries, and only needs to adjust the charging current in the battery charging policy table of different types of batteries according to the first lithium deposition detection result, and the calculation amount related to this method is small, which reduces the calculation complexity of the system and improves the execution speed of the system.

[0027] In one embodiment, after step S30 or S40, as shown in FIG. 2, the method includes steps S50 to S60 after charging the battery is completed.

[0028] In S50, after charging of the battery is completed and the battery is placed in a stationary state, stationary lithium deposition detection is performed on the battery to obtain a second lithium deposition detection result.

[0029] The stationary state refers to a state in which no other operations (e.g., discharge, charge, etc.) are performed on the battery. The stationary lithium precipitation detection refers to a method of performing lithium precipitation detection on the battery after charging of the battery is completed, and the stationary lithium precipitation detection includes, but is not limited to, a voltage stationary method, a nonlinear frequency response method, and a voltage relaxation method. The second lithium precipitation detection result is obtained after performing stationary lithium precipitation detection on the battery after charging of the battery is completed, and the second lithium precipitation detection result includes a result in which lithium precipitation phenomenon occurs in the battery and a result in which lithium precipitation phenomenon does not occur in the battery, and when the second lithium precipitation detection result is a result in which lithium precipitation phenomenon occurs in the battery, it can represent a lithium precipitation characteristic amount of the battery.

[0030] Specifically, the battery continues to be charged based on the updated charging current until charging of the battery is completed, and charging lithium deposition detection continues to be performed on the battery during the charging process of the battery, and then the fully charged battery is placed in a stationary state and stationary lithium deposition detection is performed on the battery to obtain a second lithium deposition detection result.

[0031] In one specific embodiment, step S50, i.e., after charging of the battery is completed and the battery is in a stationary state, performing stationary lithium deposition detection on the battery to obtain a second lithium deposition detection result, includes the following steps:

[0032] After charging of the battery is completed and the battery is left in a stationary state, the voltage of the battery is collected at regular intervals based on a predetermined time interval, and the collected voltages are associated with the times at which these voltages were collected and stored as voltage data.

[0033] The battery in this step refers to a battery that is waiting for detection of lithium deposition after charging is completed. The occurrence of lithium deposition in the battery during charging refers to the deposition of some lithium metal on the negative electrode of the battery during charging. The predetermined time interval may be determined based on the actual detection requirements (such as the type of battery to be detected), and may be, for example, 5s or 10s. The collection time refers to the time point corresponding to the voltage of the battery collected based on the predetermined time interval. The voltage data includes each set of voltage and its corresponding collection time.

[0034] Based on the voltage data, a time difference voltage curve is generated in a voltage-time coordinate system.

[0035] The time difference voltage curve represents a curve in which the first differential relationship of the battery changes according to the voltage, and the first differential relationship is calculated based on the collection time and the voltage. The voltage-time coordinate system is the coordinate system shown in FIG. 3, in which the horizontal axis represents the voltage of the battery to be collected, and the vertical axis represents the time corresponding to the voltage of the battery to be collected. L1 represents the time difference voltage curve, and L2 represents the curve in which the voltage of the battery to be collected changes according to the collection time. Specifically, the voltage of the battery is collected at a fixed time based on a predetermined time interval, and the collected voltages are associated with the collection times of these voltages and stored as voltage data, and then the first differential relationship corresponding to the voltage data is obtained by the time difference voltage based on the voltage data, and then the time difference voltage curve is determined.

[0036] Preferably, in this step, determining a time difference voltage curve based on the voltage data includes generating the time difference voltage curve based on the voltage data and a predetermined first derivative relationship, the predetermined first derivative relationship being calculated based on the voltages of the collected cells and the collection times for each set, the predetermined first derivative relationship being dt / dU.

[0037] Specifically, the voltages of the battery are collected at regular intervals based on a predetermined time interval, the collected voltages are associated with the collection times of these voltages and stored as voltage data, and then a predetermined first-order differential relationship is obtained based on each set of voltages and the corresponding collection times in the voltage data, and each collected voltage has a corresponding first-order differential relationship value, so that a time difference voltage curve is determined.

[0038] A second lithium deposition detection result is obtained based on the time difference voltage curve and a predetermined peak detection and identification algorithm.

[0039] A predetermined peak detection and identification algorithm is used to find a characteristic peak voltage corresponding to a characteristic peak when the characteristic peak appears in the time difference voltage curve, and the characteristic peak voltage indicates that lithium deposition occurs in the battery during charging. In this embodiment, the peak detection and identification algorithm can set a search area (e.g., bounded by time) in the voltage-time coordinate system, and when a maximum value is searched for in the area (i.e., as shown in FIG. 3, when a point appears in the time difference voltage curve L1 where the curve first rises and then falls, the characteristic peak phenomenon occurs), the point corresponding to the maximum value is determined as the characteristic peak point.

[0040] Specifically, a time difference voltage curve is created in a voltage-time coordinate system based on the above voltage data, and then a predetermined peak detection and identification algorithm is used to search for whether or not a characteristic peak voltage exists in the time difference voltage curve. If a characteristic peak voltage is found in the time difference voltage curve, the second lithium deposition detection result indicates that lithium deposition has occurred after charging of the battery is completed. If no characteristic peak voltage is found in the time difference voltage curve, the second lithium deposition detection result indicates that lithium deposition has not occurred after charging of the battery is completed.

[0041] In S60, if the second lithium deposition detection result indicates that a lithium deposition phenomenon has occurred, the charging current in the battery charging policy table is updated based on a predetermined second current reduction policy.

[0042] The second current reduction policy refers to determining a reduction ratio for reducing the charging current according to the lithium deposition characteristic amount after the charging of the battery is completed and the lithium deposition criterion corresponding to the battery, and then updating and reducing the charging current in the battery charging policy table according to the reduction ratio. For example, the reduction ratio is 1% of the current charging current, and thus, when the charging current in the battery charging policy table is 1A, the charging current can be reduced by 1%, that is, the charging current can be reduced to 0.99A. As can be understood, in the present disclosure, the predetermined ratio in the first current reduction policy and the reduction ratio in the second current reduction policy can be the same or different.

[0043] Specifically, after performing static lithium deposition detection on the battery and obtaining a second lithium deposition detection result, if the second lithium deposition detection result indicates that lithium deposition has occurred, the lithium deposition characteristic amount of the battery is further checked to obtain a lithium deposition characteristic amount corresponding to the case where lithium deposition has occurred after charging of the battery is completed, and further, the charging current in the battery charging policy table is updated based on the lithium deposition characteristic amount and a predetermined second current reduction policy.

[0044] Preferably, step S60, i.e., if the second lithium deposition detection result indicates that a lithium deposition phenomenon occurs, updating the charging current in the battery charging policy table based on a predetermined second current reduction policy, includes the following steps:

[0045] Identifying a characteristic peak voltage in the time difference voltage curve through the predetermined peak detection and identification algorithm, and recording a corresponding stable voltage in the time difference voltage curve when a predetermined stability criterion is satisfied after determining the characteristic peak voltage.

[0046] The predetermined stability criterion means that the curve value of the time difference voltage curve meets the requirement that it approaches a stable and unchanging state in the range of -100 to -∞. In this embodiment, when the change according to the voltage of the time difference voltage curve is very small over a long period of time (the curve approaches a straight line, and at this time, the curve value of the time difference voltage curve approaches a stable and unchanging state), the voltage value corresponding to the time difference voltage curve at the start of the state is recorded as a stable voltage.

[0047] Specifically, after determining a time difference voltage curve based on the voltage data, a characteristic peak voltage in the time difference voltage curve is identified by a peak detection and identification algorithm to indicate that lithium deposition occurs in the battery during charging, i.e., it is determined that a lithium deposition state exists in the battery during charging. At this time, after determining the characteristic peak voltage, it is necessary to record the stable voltage in the time difference voltage curve that corresponds to when a predetermined stability criterion is met.

[0048] A first area and a second area are determined in the voltage-time coordinate system based on the characteristic peak voltage, the stable voltage and the time difference voltage curve.

[0049] Specifically, a characteristic peak voltage in the time difference voltage curve is identified by a peak detection and identification algorithm, and a stable voltage corresponding to when a predetermined stability criterion is satisfied in the time difference voltage curve after the characteristic peak voltage appears is recorded; then, a charging voltage at the end of charging the battery is obtained; a starting point of the time difference voltage curve corresponds to the charging voltage; a reference horizontal axis and a first reference vertical axis are determined, the reference horizontal axis refers to the horizontal axis corresponding to the starting point in the voltage-time coordinate system, and the first reference vertical axis refers to the vertical axis corresponding to the characteristic peak voltage in the voltage-time coordinate system; and a first area corresponding to an area surrounded by the reference horizontal axis, the first reference vertical axis and the time difference voltage curve is calculated. In the voltage-time coordinate system shown in FIG. 3, U1 is the starting point on the time difference voltage curve corresponding to the charging voltage, U2 is the point on the time difference voltage curve corresponding to the characteristic peak voltage, U3 is the point on the time difference voltage curve corresponding to the stable voltage, L3 is the reference horizontal axis, L4 is the first reference vertical axis, and L5 is the second reference vertical axis.

[0050] A second reference vertical axis, which is the vertical axis corresponding to the stable voltage in the voltage-time coordinate system, is determined, and a second area corresponding to the area surrounded by the reference horizontal axis, the first reference vertical axis, the second reference vertical axis, and the time difference voltage curve is calculated.

[0051] A lithium deposition characteristic amount of the battery is determined based on the first region area and the second region area, and the charging current in the battery charging policy table is updated based on the lithium deposition characteristic amount and a predetermined battery lithium deposition standard.

[0052] The lithium deposition characteristic quantity represents the degree of lithium deposition during the charging process of the battery. The predetermined battery lithium deposition standard refers to a lithium deposition standard obtained by detecting the battery before shipping the battery, that is, each battery has a corresponding predetermined battery lithium deposition standard.

[0053] Specifically, a first region area is obtained based on the characteristic peak voltage and the time difference voltage curve, a second region area is obtained based on the characteristic peak voltage, the stable voltage and the time difference voltage curve, and then a lithium deposition characteristic amount of the battery is determined based on the first region area and the second region area. Further, a degree of lithium deposition occurring in the battery during this charging process is determined based on a lithium deposition standard in the shipping specification of the battery (i.e., a predetermined battery lithium deposition standard). If the lithium deposition characteristic amount exceeds the corresponding lithium deposition standard of the battery, the current charging current in the battery charging policy table needs to be reduced according to a second current reduction policy. That is, a reduction ratio by which the charging current should be reduced is determined based on a difference between the lithium deposition characteristic amount after charging of the battery is completed and the lithium deposition standard. Further, the charging current in the battery charging policy table is updated and reduced based on the reduction ratio. For example, if the lithium deposition characteristic amount after the battery is charged is greater than the lithium deposition standard, the reduction ratio is preset to 1% of the current charging current, and the charging current in the battery charging policy table is 1A, the charging current can be reduced by 1%, i.e., reduced to 0.99A, so that the next time the battery is charged, the battery is charged with the reduced charging current, thereby reducing the lithium deposition characteristic amount of the battery and further achieving the effect of protecting the battery. It can be understood that if the lithium deposition characteristic amount significantly exceeds the corresponding lithium deposition standard of the battery (for example, the excess amount is equal to or greater than a predetermined percentage of the lithium deposition standard, and the predetermined percentage may be 40%, but may be set to other percentages other than 40% as necessary, it can be understood that if the excess amount is less than the predetermined percentage, the current charging current in the battery charging policy table can be reduced according to the second current reduction policy), it indicates that the battery should be returned and inspected, so as to avoid the lithium deposition characteristic amount of the battery being too large and causing a safety accident.

[0054] The time when the characteristic peak voltage appears on the time difference voltage curve is the time when the activated lithium is completely inserted into the graphite, that is, the physical meaning of the first area refers to the time required for the "activated lithium" precipitated from the battery during charging to be inserted from the outside to the inside of the graphite. The second area, which corresponds to the area from the characteristic peak voltage to the stable voltage, represents the lithium ion concentration basically reaching equilibrium from the separator to the copper foil. Therefore, the lithium ions tend to diffuse from the outside of the graphite particles to the inside of the particles, so the distribution of lithium ions is uniform throughout the graphite particles.

[0055] Specifically, the physical meaning of the first region area refers to the time required for the "activated lithium" precipitated from the battery during charging to be inserted from the outside to the inside of the graphite. The first region area alone cannot accurately represent the total lithium precipitation characteristic of the battery, because the elapsed time is related to the lithium precipitation characteristic and the lithium insertion rate into the graphite, and the lithium insertion rate into the graphite is related to the temperature, so the lithium precipitation characteristic can only be represented by the time at the same temperature.

[0056] Therefore, the present disclosure expresses the lithium deposition rate of the battery as the reciprocal of the second area. However, during the collection time of the first area, some of the "activated lithium" that entered the negative electrode is in equilibrium in the process of other "activated lithium" being inserted into the negative electrode, so the time when some of the "activated lithium" enters the equilibrium state in the negative electrode overlaps with the collection time of the first area. However, before the characteristic peak voltage is reached, mainly the "activated lithium" enters the negative electrode, and after the characteristic peak voltage is reached, the concentration difference of lithium ions in the graphite particles of the negative electrode is at its maximum, and the lithium insertion rate of graphite (i.e., lithium deposition rate) is expressed by calculating the reciprocal of the time (i.e., the second area) from when all the "activated lithium" is completely inserted into the negative electrode to when the graphite particles of the negative electrode reach their final equilibrium state.

[0057] As pointed out in the above explanation, the area of ​​the first region is recorded as the lithium deposition time of the battery, the reciprocal of the area of ​​the second region is recorded as the lithium deposition rate of the battery, and the product of the reciprocal of the area of ​​the second region and the area of ​​the first region is recorded as the lithium deposition characteristic of the battery, i.e., the product of the lithium deposition time and the lithium deposition rate can be recorded as the lithium deposition characteristic of the battery.

[0058] In another specific embodiment, after performing static lithium precipitation detection on the battery to obtain a second lithium precipitation detection result, If the second lithium deposition detection result is that no lithium deposition phenomenon occurs, that is, no lithium deposition phenomenon occurs after the battery is charged, the method further includes the step of charging the battery with the current charging current in the battery charging policy table in the next battery charging process, and not updating the charging current in the battery charging policy table, to indicate that the lithium deposition characteristic amount of the battery is not increased. Preferably, if the characteristic peak voltage in the time difference voltage curve is not identified by the predetermined peak detection and identification algorithm, it indicates that no lithium deposition occurs in the battery during the charging process. Specifically, since the characteristic peak voltage in the present disclosure indicates that lithium deposition occurs in the battery during the charging process in a physical sense, after determining the time difference voltage curve based on the voltage data, if the characteristic peak voltage in the time difference voltage curve is not identified by the peak detection and identification algorithm, it indicates that no lithium deposition occurs in the battery during the charging process.

[0059] In this embodiment, after the charging of the battery is completed, a static lithium deposition detection is performed on the battery to determine whether lithium deposition occurs in the battery after charging is completed; when lithium deposition occurs in the battery, the current charging current of the battery is reduced based on a predetermined second current reduction policy, thereby improving the safety of the battery charging process; and when a charging command is received next time, the battery is charged with the updated charging current in the battery charging policy table, thereby avoiding the occurrence of lithium deposition and further improving the safety of the battery.

[0060] In one embodiment, step S20, ie, a step of performing charging lithium deposition detection on the battery at least once to obtain a first lithium deposition detection result during the charging process of the battery, includes steps S201 to S202 as shown in FIG.

[0061] In S201, a first electrochemical impedance and a second electrochemical impedance of the battery at a predetermined frequency are obtained based on a predetermined SOC change amount, the predetermined SOC change amount is equal to a difference between a second SOC value and the first SOC value, the first SOC value corresponds to the first electrochemical impedance, the second SOC value corresponds to the second electrochemical impedance, and both the first SOC value and the second SOC value are greater than a predetermined SOC threshold value.

[0062] In the detection of lithium deposition during one charge, the first SOC value refers to the ratio between the current remaining capacity of the battery before the detection of lithium deposition during charging and the capacity of the battery in a fully charged state, and the second SOC value refers to the ratio between the current remaining capacity of the battery after the detection of lithium deposition during charging and the capacity of the battery in a fully charged state. Preferably, the predetermined SOC threshold may be determined based on the type of the battery and the charging demand, and for example, the predetermined SOC threshold may be 70%, 75%, etc. The electrochemical impedance refers to the ratio between the AC voltage and the current signal of the battery during the charging process, and the electrochemical impedance corresponds to the SOC value of the battery and a predetermined frequency (for example, the first electrochemical impedance corresponds to the first SOC value and a predetermined frequency, and the second electrochemical impedance corresponds to the second SOC value and a predetermined frequency). For example, the predetermined frequency may be any value selected from a frequency range of 0.01 Hz to 10 Hz, and the predetermined frequency may be determined based on the type of battery, that is, the predetermined frequency corresponding to different types of batteries (e.g., power battery, 3C battery) is also different.

[0063] Preferably, the predetermined SOC change amount may be set as needed, for example, 5%, 10%, etc., and assuming that the predetermined SOC change amount is 5% and the predetermined SOC threshold is 70%, the first SOC value is 75% and the second SOC value is 80%.

[0064] Specifically, in this embodiment, an electrochemical impedance measurement method is used to detect lithium deposition during charging of the battery, and after charging the battery based on the charging current in the battery charging policy table, the first electrochemical impedance and the second electrochemical impedance of the battery at a predetermined frequency are obtained based on a predetermined SOC change amount.

[0065] In one specific embodiment, only one lithium deposition detection is performed on the battery during charging. Assuming that the first lithium deposition detection result indicates that lithium deposition has occurred in the battery during charging, there is only one set of corresponding first and second electrochemical impedances in this lithium deposition detection, that is, the first lithium deposition detection result determined based on the set of first and second electrochemical impedances indicates that lithium deposition has occurred in the battery during charging.

[0066] In another specific embodiment, assume that the battery is subjected to multiple lithium deposition detections during charging, and the last lithium deposition detection result is that the battery has lithium deposition during charging. At this time, there are multiple sets of corresponding first and second electrochemical impedances in the lithium deposition detection. If the first lithium deposition detection result is that the battery has no lithium deposition during charging, the second electrochemical impedance at this time can be used as the new first electrochemical impedance in the next lithium deposition detection, and the corresponding new second electrochemical impedance is obtained according to a predetermined SOC change amount, and the new first lithium deposition detection result is determined according to the new first electrochemical impedance and the new second electrochemical impedance. The difference between the corresponding second SOC value and the first SOC value of each set is equal to the predetermined SOC change amount.

[0067] In S202, a first lithium deposition detection result at the second detection time of the battery is determined based on the first electrochemical impedance and the second electrochemical impedance.

[0068] Specifically, after obtaining a second electrochemical impedance of the battery at a predetermined frequency at the second detection time, the first electrochemical impedance is compared with the second electrochemical impedance to determine a first lithium deposition detection result of the battery at the second detection time based on the result obtained by the comparison.

[0069] After comparing the first electrochemical impedance with the second electrochemical impedance, if the first electrochemical impedance is greater than the second electrochemical impedance, it is determined that the first lithium deposition detection result at the second detection time indicates that a lithium deposition phenomenon is occurring.

[0070] After comparing the first electrochemical impedance with the second electrochemical impedance, if the first electrochemical impedance is equal to or less than the second electrochemical impedance, it is determined that the first lithium deposition detection result at the second detection time is not a lithium deposition phenomenon.

[0071] It should be understood that the magnitude of the numbers of each step in the above embodiments does not mean the order of execution, and the execution order of each process should be determined according to the function and internal logic of the process, and should not be construed as any limitation on the implementation process of the embodiments of the present disclosure.

[0072] As shown in FIG. 5, a battery charging system based on lithium precipitation detection according to an embodiment includes: a charging policy table acquisition module 10 for acquiring a battery charging policy table after receiving a battery charging command; A charging lithium deposition detection module 20 charges the battery according to the charging current in the battery charging policy table, and performs charging lithium deposition detection on the battery at least once during the charging process of the battery to obtain a first lithium deposition detection result; If the first lithium deposition detection result indicates that lithium deposition has not occurred, continue charging the battery based on the charging current, and continue to perform charging lithium deposition detection on the battery during the charging process of the battery, and if the first lithium deposition detection result indicates that lithium deposition has occurred, When it becomes Or, charging of the battery is completed. When a first charging module 30 for stopping charging lithium deposition detection for the battery; and a second charging module 40 that, when the first lithium deposition detection result indicates that a lithium deposition phenomenon has occurred, updates the charging current in the battery charging policy table based on a predetermined first current reduction policy, and continues charging the battery based on the updated charging current until charging of the battery is completed.

[0073] Preferably, as shown in FIG. 6, the lithium deposition detection based battery charging system comprises: a stationary lithium deposition detection module 50 that performs stationary lithium deposition detection on the battery after charging of the battery is completed and the battery is in a stationary state, and obtains a second lithium deposition detection result; and a charging current update module 60 for updating the charging current in the battery charging policy table according to a second predetermined current reduction policy when the second lithium deposition detection result indicates that a lithium deposition phenomenon occurs.

[0074] Preferably, the static lithium deposition detection module 50 comprises: a voltage collecting unit that collects the voltage of the battery at a predetermined time interval after the charging of the battery is completed and the battery is in a stationary state, and stores the collected voltages as voltage data in association with the collection times of the voltages; a curve creation unit for creating a time difference voltage curve in a voltage-time coordinate system based on the voltage data; and a peak detection and identification unit for obtaining a second lithium precipitation detection result according to the time difference voltage curve and a predetermined peak detection and identification algorithm.

[0075] Preferably, the charging current update module 60 comprises: a voltage recording unit for identifying a characteristic peak voltage in the time difference voltage curve through the predetermined peak detection and identification algorithm, and recording a corresponding stable voltage in the time difference voltage curve when a predetermined stability criterion is satisfied after determining the characteristic peak voltage; an area determining unit for determining a first area and a second area in the voltage-time coordinate system according to the characteristic peak voltage, the stable voltage and the time difference voltage curve; a lithium precipitation feature amount determining unit for determining a lithium precipitation feature amount of the battery based on the first region area and the second region area; and a current update unit for updating the charging current in the battery charging policy table based on the lithium deposition characteristic and a predetermined battery lithium deposition criterion.

[0076] Preferably, the charging lithium deposition detection module 20 includes: an electrochemical impedance acquisition unit that acquires a first electrochemical impedance and a second electrochemical impedance of the battery at a predetermined frequency based on a predetermined SOC change amount, wherein the first SOC value corresponding to the first electrochemical impedance and the second SOC value corresponding to the second electrochemical impedance are both greater than a predetermined SOC threshold, and a difference between the second SOC value and the first SOC value is equal to the predetermined SOC change amount; and a lithium deposition detection result acquisition unit for acquiring the first lithium deposition detection result based on the first electrochemical impedance and the second electrochemical impedance.

[0077] Preferably, the lithium deposition detection result acquisition unit includes: a first impedance comparing unit for determining that the first lithium deposition detection result indicates that a lithium deposition phenomenon occurs when the first electrochemical impedance is greater than the second electrochemical impedance; and a second impedance comparing unit for determining that the first lithium deposition detection result does not indicate that a lithium deposition phenomenon occurs if the first electrochemical impedance is equal to or less than the second electrochemical impedance.

[0078] An automobile according to one embodiment includes a battery charging system based on lithium deposition detection as described above.

[0079] The computer device according to an embodiment may be a server, and its internal configuration diagram is shown in FIG. 7. The computer device includes a processor, a memory, a network interface, and a database, which are connected via a system bus. The processor of the computer device provides calculation and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the execution of the operating system and the computer program in the non-volatile storage medium. The network interface of the computer device connects and communicates with an external terminal via a network. When the computer program is executed by the processor, it realizes a battery charging method based on lithium deposition detection.

[0080] A computing device according to one embodiment includes a memory, a processor, and a computer program stored in the memory and executable on the processor, which, when executed by the processor, realizes the battery charging method based on lithium deposition detection according to the above embodiment.

[0081] A computer-readable storage medium according to an embodiment stores a computer program that, when executed by a processor, realizes a battery charging method based on lithium deposition detection according to an embodiment.

[0082] As can be understood by those skilled in the art, the implementation of all or part of the flow in the method of the above embodiments can be completed by instructing related hardware by a computer program, and the above computer program can be stored in a non-volatile computer-readable storage medium, and when the computer program is executed, it may include the flow of each of the above method embodiments. Any reference to memory, storage, database, or other medium used in each embodiment of the present application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of example and not limitation, RAM is available in a variety of forms, such as Static RAM (SRAM), Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), Double Data Rate SDRAM (DDRSDRAM), Enhanced SDRAM (ESDRAM), Synchronous Link DRAM (SLDRAM), Rambus Direct RAM (RDRAM), Direct Rambus Dynamic RAM (DRDRAM), and Rambus Dynamic RAM (RDRAM).

[0083] In order to make it clear to those skilled in the art, the above functional units and modules have been described as examples for ease and conciseness of explanation. In actual application, however, the above functions can be allocated and completed by different functional units and modules as needed, that is, the internal structure of the above device can be divided into different functional units or modules to complete all or part of the functions described above.

[0084] The above embodiments are merely for illustrating the technical means of the present disclosure, and are not limiting. The present disclosure has been described in detail with reference to the above embodiments. However, it should be understood by those skilled in the art that the technical means described in each of the above embodiments can still be modified or some of the technical features can be equivalently replaced, and these modifications or replacements do not deviate the essence of the corresponding technical means from the spirit and scope of the technical means of each of the embodiments of the present disclosure, and all of them should be included in the protection scope of the present disclosure.

Claims

1. obtaining a battery charging policy table after receiving a battery charging command; Charging the battery according to the charging current in the battery charging policy table, and during the charging process of the battery, performing charging lithium deposition detection on the battery at least once to obtain a first lithium deposition detection result; When the first lithium deposition detection result indicates that lithium deposition has not occurred, continuing to charge the battery based on the charging current, and continuing to perform charging lithium deposition detection on the battery during the charging process of the battery, and when the first lithium deposition detection result indicates that lithium deposition has occurred or when charging of the battery is completed, stopping charging lithium deposition detection on the battery; updating the charging current in the battery charging policy table based on a predetermined first current reduction policy when the first lithium deposition detection result indicates that a lithium deposition phenomenon has occurred, and continuing to charge the battery based on the updated charging current until charging of the battery is completed; Furthermore, after charging of the battery is completed, After charging of the battery is completed and the battery is in a stationary state, performing stationary lithium deposition detection on the battery to obtain a second lithium deposition detection result; and updating the charging current in the battery charging policy table based on a predetermined second current reduction policy when the second lithium deposition detection result indicates that a lithium deposition phenomenon is occurring.

2. a step of performing stationary lithium deposition detection on the battery after charging of the battery is completed and the battery is in a stationary state, and obtaining a second lithium deposition detection result, After charging of the battery is completed and the battery is in a stationary state, collecting voltages of the battery at regular intervals based on a predetermined time interval, and storing the collected voltages as voltage data in association with the collection times of the voltages; generating a time difference voltage curve in a voltage-time coordinate system based on the voltage data; and obtaining a second lithium precipitation detection result based on the time difference voltage curve and a predetermined peak detection and identification algorithm.

3. updating the charging current in the battery charging policy table based on a second predetermined current decay policy; identifying a characteristic peak voltage in the time difference voltage curve using the predetermined peak detection and identification algorithm, and after determining the characteristic peak voltage, recording a stable voltage in the time difference voltage curve corresponding to when a predetermined stability criterion is satisfied; determining a first area and a second area in the voltage-time coordinate system based on the characteristic peak voltage, the stable voltage and the time difference voltage curve; determining a lithium precipitation characteristic of the battery based on the first area and the second area; and updating the charging current in the battery charging policy table based on the lithium deposition feature and a predetermined battery lithium deposition criterion.

4. After receiving a battery charging command, obtaining a battery charging policy table; Charging the battery according to the charging current in the battery charging policy table, and during the charging process of the battery, performing charging lithium deposition detection on the battery at least once to obtain a first lithium deposition detection result; When the first lithium deposition detection result indicates that lithium deposition has not occurred, continuing to charge the battery based on the charging current, and continuing to perform charging lithium deposition detection on the battery during the charging process of the battery, and when the first lithium deposition detection result indicates that lithium deposition has occurred or when charging of the battery is completed, stopping charging lithium deposition detection on the battery; updating the charging current in the battery charging policy table based on a predetermined first current reduction policy when the first lithium deposition detection result indicates that a lithium deposition phenomenon has occurred, and continuing to charge the battery based on the updated charging current until charging of the battery is completed; In the charging process of the battery, the step of performing charging lithium deposition detection on the battery at least once to obtain a first lithium deposition detection result includes: obtaining a first electrochemical impedance and a second electrochemical impedance of the battery at a predetermined frequency based on a predetermined SOC change amount, wherein the predetermined SOC change amount is equal to a difference between a second SOC value and a first SOC value, the first SOC value corresponds to the first electrochemical impedance, the second SOC value corresponds to the second electrochemical impedance, and both the first SOC value and the second SOC value are greater than a predetermined SOC threshold value; and acquiring the first lithium precipitation detection result based on the first electrochemical impedance and the second electrochemical impedance.

5. The step of obtaining a first lithium deposition detection result of the battery based on the first electrochemical impedance and the second electrochemical impedance includes: determining that the first lithium deposition detection result indicates that a lithium deposition phenomenon occurs when the first electrochemical impedance is greater than the second electrochemical impedance; 5. The battery charging method based on lithium precipitation detection according to claim 4, further comprising: determining that the first lithium precipitation detection result indicates that a lithium precipitation phenomenon does not occur when the first electrochemical impedance is equal to or less than the second electrochemical impedance.

6. a charging policy table acquisition module for acquiring a battery charging policy table after receiving a battery charging command; a charging lithium deposition detection module for charging a battery according to a charging current in the battery charging policy table, and performing charging lithium deposition detection on the battery at least once during the charging process of the battery to obtain a first lithium deposition detection result; a first charging module that, when the first lithium deposition detection result indicates that lithium deposition has not occurred, continues to charge the battery based on the charging current and continues to perform charging lithium deposition detection on the battery during the charging process of the battery, and stops charging lithium deposition detection on the battery when the first lithium deposition detection result indicates that lithium deposition has occurred or when charging of the battery is completed; a second charging module that, when the first lithium deposition detection result indicates that a lithium deposition phenomenon is occurring, updates the charging current in the battery charging policy table based on a predetermined first current reduction policy, and continues to charge the battery based on the updated charging current until charging of the battery is completed; a stationary lithium deposition detection module that performs lithium deposition detection on the battery after charging of the battery is completed and the battery is in a stationary state, and obtains a second lithium deposition detection result; a charging current update module that updates the charging current in the battery charging policy table based on a predetermined second current reduction policy when the second lithium deposition detection result indicates that a lithium deposition phenomenon is occurring.

7. 7. A vehicle comprising a lithium deposition detection based battery charging system according to claim 6.

8. A computer-readable storage medium having a computer program stored thereon, the computer program being characterized in that, when executed by a processor, the computer program realizes the battery charging method based on lithium precipitation detection according to any one of claims 1 to 5. The computer-readable storage medium.

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