Nondestructive testing method and system for abnormal lithium precipitation of battery, electronic equipment and storage medium

Abstract

The invention provides a nondestructive testing method and system for abnormal lithium precipitation of a battery, electronic equipment and a storage medium, and relates to the technical field of battery detection.The method comprises the steps that two-stage charging is executed on a target battery, in the first charging stage, the target battery is charged to a charging cut-off voltage, and after a preset standing duration, the target battery enters the second charging stage, in the second charging stage, the target battery is recharged to the charging cut-off voltage with the target charging current, and the minimum charging current in the first charging stage is larger than the target charging current; acquiring a voltage change curve of each battery cell in the target battery in the charging process of the second charging stage; according to the voltage change curve, calculating the voltage change rate of the voltage of each battery cell along with the time, and obtaining a voltage change rate curve; and determining the abnormal lithium precipitation battery cell according to the outlier change of the voltage change rate curve of each battery cell. According to the invention, real-time on-line, low-cost and high-robustness lithium precipitation risk early warning can be realized.

Description

Technical Field

[0001] This application relates to the field of battery testing technology, specifically to a non-destructive testing method, system, electronic device, and storage medium for abnormal lithium plating in batteries. Background Technology

[0002] With the popularization of new energy vehicles, the market demand for lithium-ion batteries continues to rise. However, lithium plating is an unavoidable evolutionary process during the use of lithium-ion batteries, which may lead to safety hazards such as thermal runaway in severe cases. Therefore, monitoring and early warning of abnormal lithium plating during the use of lithium batteries is extremely important.

[0003] Traditional lithium plating detection methods typically require destructive testing by disassembling the battery. This approach is not only inefficient but also struggles to provide timely feedback on anomalies. While current detection methods based on expansion force trends, ultrasound, and impedance are suitable for cell testing and verification in laboratory environments, they still cannot achieve rapid response to lithium plating anomalies in real-world applications. Therefore, how to efficiently and conveniently monitor lithium plating in lithium-ion batteries in practical applications is a pressing issue that needs to be addressed. Summary of the Invention

[0004] In view of the above-mentioned shortcomings of the prior art, this application provides a non-destructive testing method, system, electronic device and storage medium for abnormal lithium plating in batteries, which effectively solves the problem of not being able to efficiently and conveniently monitor lithium plating in lithium-ion batteries in practical application scenarios.

[0005] In a first aspect, this application provides a non-destructive testing method for abnormal lithium plating in batteries, the method comprising: The target battery is charged in two stages. In the first charging stage, the target battery is charged to the charging cutoff voltage. After a preset resting time, the second charging stage begins. In the second charging stage, the target battery is recharged to the charging cutoff voltage with the target charging current. The minimum charging current in the first charging stage is greater than the target charging current. Obtain the voltage change curves of each cell in the target battery during the second charging stage; Calculate the rate of change of voltage of each cell over time based on the voltage change curve to obtain the rate of change of voltage curve; Abnormal lithium plating cells are identified based on outliers in the voltage change rate curves of each cell.

[0006] In an optional implementation, the step of identifying abnormal lithium-plating cells based on outlier variations in the voltage change rate curves of each cell includes: Calculate the target confidence interval for the voltage change rate of all cells at each voltage value based on the voltage change rate curve; The lower limit of the target confidence interval is used as the outlier threshold of the voltage change rate; If the voltage change rate of a target cell is consistently less than the outlier threshold within a continuous voltage range, then the target cell is identified as an abnormal lithium plating cell.

[0007] In an optional implementation, the length of the continuous voltage range is greater than or equal to 10mV, and the target confidence interval is a 95% confidence interval.

[0008] In an optional implementation, the step of identifying abnormal lithium-plating cells based on outlier variations in the voltage change rate curves of each cell includes: Calculate the average voltage change rate of all cells at each voltage value based on the voltage change rate curve. The outlier threshold of the voltage change rate is determined based on the average value; If the voltage change rate of a target cell is consistently less than the outlier threshold within a continuous voltage range, then the target cell is identified as an abnormal lithium plating cell.

[0009] In an optional implementation, the length of the continuous voltage range is greater than or equal to 10mV, and the outlier threshold is 75% of the average value.

[0010] In an optional implementation, obtaining the voltage change curves of each cell in the target battery during the second charging stage includes: The cell voltage of each cell in the target battery is collected at preset time intervals during the second charging stage. The voltage change curves of each cell are constructed based on the preset time interval and the cell voltage.

[0011] In an optional implementation, the target charging current is less than or equal to 0.1C, and the preset resting time is less than or equal to 30 minutes.

[0012] Secondly, this application provides a non-destructive testing system for abnormal lithium plating in batteries, the system comprising: The charging execution module is used to perform two-stage charging on the target battery. In the first charging stage, the target battery is charged to the charging cutoff voltage. After a preset resting time, the second charging stage is entered. In the second charging stage, the target battery is recharged to the charging cutoff voltage with a target charging current. The minimum charging current in the first charging stage is greater than the target charging current. The parameter acquisition module is used to acquire the voltage change curves of each cell in the target battery during the second charging stage; The parameter calculation module is used to calculate the rate of change of voltage of each cell over time based on the voltage change curve, and obtain the rate of change of voltage curve. The lithium plating detection module is used to identify abnormal lithium plating cells based on outlier changes in the voltage change rate curves of each cell.

[0013] Thirdly, this application provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the non-destructive testing method for abnormal lithium plating in batteries as described in the first aspect of this application.

[0014] Fourthly, this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the non-destructive testing method for abnormal lithium plating in batteries as described in the first aspect of this application.

[0015] The battery abnormal lithium plating non-destructive testing method, system, electronic device, and storage medium provided in this application utilize the voltage response characteristics of the charging process itself. Through a staged charging strategy, the battery enters a near-quasi-static state, effectively reducing polarization interference and highlighting the abnormal voltage plateau caused by lithium plating. This is manifested as a continuous interval with a significantly reduced local slope on the voltage change curve. Furthermore, a dynamic judgment mechanism based on cell group statistics is introduced. By analyzing the distribution characteristics of the voltage change rate over time, outlier behaviors deviating from the normal range are identified, avoiding the impact of individual differences on the reliability of the judgment. The entire detection process requires no additional hardware, does not damage the battery structure, and does not rely on lag stages such as resting or discharging. It achieves truly real-time, online, low-cost, and highly robust early warning of lithium plating risks, significantly improving the safety management level of secondary use and the entire life cycle of automotive batteries. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic flowchart of the non-destructive testing method for abnormal lithium plating in batteries provided in the embodiments of this application; Figure 2 This is a first schematic diagram of the voltage change curves of each cell in a target battery in an embodiment of this application; Figure 3 This is a second schematic diagram of the voltage change curves of each cell in a target battery in an embodiment of this application; Figure 4This is a first schematic diagram of the voltage change rate curves of each cell in a target battery in an embodiment of this application; Figure 5 This is a second schematic diagram of the voltage change rate curves of each cell in a target battery in an embodiment of this application; Figure 6 This is a comparative schematic diagram of the negative electrode interface after disassembly of a target battery in an embodiment of this application; Figure 7 This is a schematic diagram of the non-destructive testing system for abnormal lithium plating in batteries provided in this application embodiment; Figure 8 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application.

[0018] Explanation of key component symbols: 200. Battery abnormal lithium plating non-destructive testing system; 210. Charging execution module; 220. Parameter acquisition module; 230. Parameter calculation module; 240. Lithium plating detection module; 300. Electronic equipment; 310. Processor; 320. Communication interface; 330. Memory; 340. Communication bus. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be further described clearly and completely below with reference to the accompanying drawings of the embodiments. It should be noted that the described embodiments are merely some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0022] Currently, retired power battery packs for new energy vehicles exhibit varying degrees of cell aging. Even when the overall state of health (SOH) of the battery pack reaches the retirement standard of 80%, a significant number of cells still possess SOH values ​​approaching 85% or even 90%. These cells, in the later stages of their lifespan, carry a relatively increased risk of lithium plating when entering the secondary utilization stage. Therefore, the safety monitoring of lithium plating in these cells is particularly crucial.

[0023] Traditional lithium plating detection methods typically require battery disassembly for testing. This method is not only destructive but also inefficient and lacks timely feedback on anomalies. Methods based on expansion force change trend analysis, ultrasonic testing, and online impedance monitoring are generally only suitable for single-cell testing in laboratory environments. In practical applications, battery modules or packs often lack corresponding monitoring devices, making real-time response to anomalies impossible. Currently, the industry commonly uses methods to determine lithium plating by analyzing the battery's resting curve after charging and the current state during the constant voltage process at high cutoff voltage. However, these methods have significant time lag, requiring the charging process or even the resting phase to complete before lithium plating can be assessed. Given the potential risks of thermal runaway accidents, how to efficiently and conveniently monitor lithium plating in lithium-ion batteries in practical applications is an urgent problem to be solved.

[0024] Example 1 This application provides a non-destructive testing method for abnormal lithium plating in batteries, effectively solving the problem of inefficient and convenient monitoring of lithium plating in lithium-ion batteries in practical application scenarios. Figure 1 This is a schematic flowchart of the non-destructive testing method for abnormal lithium plating in batteries provided in the embodiments of this application, as shown below. Figure 1 As shown, the method includes the following steps: S100. Perform two-stage charging on the target battery. In the first charging stage, the target battery is charged to the charging cutoff voltage. After a preset resting time, the second charging stage begins. In the second charging stage, the target battery is recharged to the charging cutoff voltage using the target charging current. The minimum charging current in the first charging stage is greater than the target charging current.

[0025] In this embodiment, the target battery can be a vehicle-mounted battery pack. Since current vehicle-mounted or charging station charging strategies primarily employ fast charging, the polarization within the battery cells is high under the large current of fast charging, resulting in a rapid voltage response and rise. Therefore, abnormal lithium plating signals within the cells are easily masked by the polarization voltage under high-current charging, making them difficult to detect in external voltage characteristics. However, in the low-current charging stage, cell polarization is significantly reduced, similar to a quasi-static charging process. During this process, the voltage plateau caused by lithium plating becomes more clearly apparent. The lithium plating process involves lithium ions forming lithium dendrites at the negative electrode, resulting in a new phase reaction within the battery. This manifests as a new voltage plateau in a voltage range that previously lacked one on the voltage curve. Therefore, this embodiment performs a two-stage charging process on the target battery. The first charging stage is a normal charging stage, and the second charging stage uses a low-current charging method. The minimum charging current in the first charging stage is greater than the target charging current in the second charging stage.

[0026] The first charging stage charges the target battery to the charging cutoff voltage, and after a preset resting time, it enters the second charging stage.

[0027] Understandably, in practical applications, each vehicle-side battery pack has a fixed voltage operating range, and the upper limit of this fixed voltage operating range is the charging cut-off voltage.

[0028] In this embodiment, the preset resting time is less than or equal to 30 minutes. During high-current charging, lithium deposits accumulate in the cell, forming lithium dendrites, which pose a certain safety risk to the target battery. If the resting time is too long, the risk of thermal runaway increases if abnormal lithium deposits occur in the target battery, and prolonged resting poses a certain safety risk to the target battery. Simultaneously, during the resting process, there is a lithium concentration difference between the lithium deposit site and its adjacent location within the cell. Due to concentration diffusion during resting, the lithium deposited in the cell will, to some extent, be re-intercalated into the negative electrode. The longer the resting time, the more the concentration diffusion effect continues, resulting in more re-intercalated lithium, thus increasing the detection limit in the second charging stage and hindering the early detection and handling of safety risks. Therefore, setting the preset resting time to within 30 minutes balances safety and detection sensitivity, avoiding the risk of thermal runaway exacerbated by prolonged resting while suppressing lithium re-intercalation caused by concentration diffusion in the lithium dendrite neighborhood. This ensures that the lithium deposit platform signal is not weakened during low-current charging in the second charging stage, improving the early anomaly identification rate.

[0029] As an optional implementation of this application, the first charging stage can be either a stepped charging mode to charge to the charging cutoff voltage or a constant current charging mode to charge to the charging cutoff voltage.

[0030] In the embodiments of this application, the second charging stage recharges the target battery to the charging cutoff voltage with a target charging current. The second charging stage uses the smallest possible target charging current to ensure that the battery charging process is similar to a quasi-static process, which can more clearly highlight the voltage plateau signal generated by abnormal lithium plating.

[0031] As an optional implementation of this application, the target charging current can be set to be less than or equal to 0.1C according to the standard charging current in the cell specification sheet. In this application embodiment, the target charging current can be set to 0.05C.

[0032] Based on this, a two-stage charging design is adopted to balance engineering feasibility and detection effectiveness. The first charging stage adapts to the existing fast charging strategy to ensure charging efficiency, while the second charging stage switches to low-current charging to significantly suppress polarization. This allows the thermodynamic voltage plateau caused by lithium plating to be clearly highlighted on the subsequent voltage change curve, breaking through the technical bottleneck that the voltage signal is masked under high-current charging. This enables non-destructive, online, and high signal-to-noise ratio abnormal lithium plating identification.

[0033] S200: Obtain the voltage change curves of each cell in the target battery during the second charging stage.

[0034] In this embodiment, based on the high-precision single-cell voltage acquisition channel of the vehicle-side battery management system (BMS), the voltage data of each cell of the target battery is synchronously recorded during the low-current charging process in the second charging stage. U With time data t The sampling time interval is set to continuously record the entire process from the start to the end of the second charging stage. The sampling time interval can be any time between 5 seconds and 1 minute, and can be selected based on the total charging time and actual application scenario to balance detail and smoothness. The voltage values ​​of each cell ID are arranged in chronological order, and the voltage is plotted. U -time t The curve is the voltage change curve of each cell in the target battery.

[0035] For example, Figure 2 This is a first schematic diagram of the voltage change curves of each cell in a target battery in an embodiment of this application, as shown below. Figure 2 The figure shows the voltage data of each cell when the sampling time interval is 5 seconds. U Data over time t The changes. Figure 3 This is a second schematic diagram of the voltage change curves of each cell in a target battery in an embodiment of this application, as shown in the figure. Figure 3 As shown, this reflects a sampling time interval of 1. min At that time, the voltage data of each cell U Data over time tThe changes.

[0036] S300. Calculate the rate of change of voltage of each cell over time based on the voltage change curve, and obtain the rate of change of voltage curve.

[0037] As an optional implementation of this application, the original voltage data in the voltage change curve can first be preprocessed. Moving average or low-pass filtering can be used to remove high-frequency noise and ensure uniform sampling time intervals. Then, the time derivative is calculated on the smoothed voltage data sequence. This can be achieved by using the central difference method or Savitzky-Golay convolution filtering to integrate smoothing and differentiation, obtaining the rate of change of voltage for each cell over time. dU / dt Finally, the voltage data of each cell was... U The horizontal axis represents the rate of change of voltage at any given time. dU / dt Plot a curve on the vertical axis, generating a coordinate point at each sampling time. U , dU / dt By connecting them in chronological order, the voltage change rate curve can be obtained. Each curve can clearly reflect the change in polarization degree of each cell during the charging process.

[0038] For example, Figure 4 This is a first schematic diagram of the voltage change rate curves of each cell in a target battery in an embodiment of this application, as shown below. Figure 4 As shown, the sampling time interval is 5s. Due to the high time resolution, it can capture the instantaneous voltage fluctuations and subtle changes at the inflection point from constant current to constant voltage, resulting in rich curve details. Figure 5 This is a second schematic diagram showing the voltage change rate curves of each cell in a target battery in an embodiment of this application, as shown below. Figure 5 As shown, the sampling time interval is 1 minute, which has a large time span, smoothing out short-term fluctuations and making the curve smoother.

[0039] S400. Identify abnormal lithium-plating cells based on outlier changes in the voltage change rate curves of each cell.

[0040] In this embodiment, when abnormal lithium plating occurs at the negative electrode of the battery cell, some lithium ions no longer embed in the graphite layer but are reduced to metallic lithium on the surface, leading to a new phase equilibrium reaction and generating a new voltage plateau. This is manifested as the voltage hardly increasing with time within a specific voltage range, i.e., the voltage change rate is... dU / dt Abnormally low. In a normal battery cell, the active material continues to de-intercalate and re-intercalate lithium across the entire voltage range, resulting in a low voltage change rate. dU / dt Maintaining the population mean level. Therefore, due to the dominance of the new phase reaction and the shunting of the Faraday current, lithium-plated cells exhibit a new voltage plateau. Thus, outlier lithium-plated cells can be identified based on the outlier changes in the voltage change rate curve. Optionally, confidence intervals can be used to characterize outlier changes, as follows: S410. Calculate the target confidence interval for the rate of change of voltage of all cells at each voltage value based on the rate of change of voltage curve.

[0041] As an optional implementation of this application, the target confidence interval can be set to a 95% confidence interval. The voltage change rate of each cell at each voltage value can be obtained from the voltage change rate curve. The voltage change rate of each cell is based on a normal distribution or... t The distribution calculation method can obtain the 95% confidence interval for each voltage value.

[0042] S420. Use the lower limit of the target confidence interval as the outlier threshold for the voltage change rate.

[0043] In this embodiment, the lower limit of the 95% confidence interval is used as the outlier threshold of the voltage change rate, which can avoid interference from individual parameter drift and enhance robustness.

[0044] S430. If the voltage change rate of a target cell is consistently less than the outlier threshold within a continuous voltage range, the target cell is identified as an abnormal lithium plating cell.

[0045] Furthermore, if a target cell consistently exhibits a voltage change rate less than the outlier threshold (i.e., the lower limit of the 95% confidence interval) over a continuous voltage range, then it indicates that the voltage change rate of that target cell is... dU / dt The value is abnormally low, therefore the target cell is identified as an abnormal lithium plating cell, a battery lithium plating warning is issued and the target cell number is fed back.

[0046] In this embodiment of the application, the length of the continuous voltage interval is greater than or equal to 10. mV This process eliminates noise and jitter, ensuring the voltage platform exhibits thermodynamic and kinetic consistency, thereby enabling high-confidence identification of early, non-destructive, and online lithium plating states. This continuous voltage range can be set according to actual conditions. For example, in practical vehicle applications, considering insufficient actual cell sampling frequency (e.g., acquiring one frame of voltage data every 30 seconds or 1 minute), voltage counting may be affected. mV The intervals are above the specified range, so it is advisable to broaden the judgment range for continuous voltage intervals.

[0047] As another optional implementation of this application, the mean can be used to characterize outlier changes, and the steps are as follows: S440. Calculate the average voltage change rate of all cells at each voltage value based on the voltage change rate curve.

[0048] In this embodiment of the application, the voltage change rate of each cell at each voltage value can be obtained from the voltage change rate curve, and the average value of the voltage change rate at each voltage value is obtained by calculating the average value of the voltage change rate of each cell.

[0049] S450. Determine the outlier threshold for the rate of change of voltage based on the average value.

[0050] Optionally, 75% of the average rate of change of voltage at each voltage value can be used as the outlier threshold.

[0051] S460. If the voltage change rate of a target cell is consistently less than the outlier threshold within a continuous voltage range, the target cell is identified as an abnormal lithium plating cell.

[0052] Furthermore, in this embodiment, the length of the continuous voltage range is greater than or equal to 10mV. If the voltage change rate of a target cell in the continuous voltage range is consistently less than the outlier threshold, i.e., 75% of the average value, then it indicates that the voltage change rate of the target cell is... dU / dt The value is abnormally low, therefore the target cell is identified as an abnormal lithium plating cell, a battery lithium plating warning is issued and the target cell number is fed back.

[0053] To verify the effectiveness of the non-destructive testing method for abnormal lithium plating in batteries provided in this application, a target battery was processed using the above steps S100-S400, and the voltage change rate at the same voltage was obtained at sampling time intervals of 5s and 10s, respectively. dU / dt、 Data including 95% confidence intervals and average values, etc. Table 1 shows the data results for the same voltage value at different sampling time intervals. As shown in Table 1, the voltage change rate of cells with cell serial numbers 7 and 8 at 3.436V and 3.52V at different sampling time intervals. dU / dt All are less than the lower limit of the 95% confidence interval and 75% of the average value, and the rate of change of voltage within the continuous voltage range of 3.42V-3.52V is... dU / dt Since the values ​​are consistently less than the lower limit of the 95% confidence interval and 75% of the average, cells with serial numbers 7 and 8 are considered abnormal cells, while cells with serial numbers 1-6 are considered normal cells. Figure 6 This is a comparative schematic diagram of the negative electrode interface after disassembling a target battery in an embodiment of this application, such as... Figure 6 As shown, compared with normal cells, cells with serial numbers 7 and 8 both exhibit severe lithium plating.

[0054] Table 1. Schematic diagram of data results for the same voltage value at different sampling time intervals.

[0055] The battery abnormal lithium plating non-destructive testing method, system, electronic device, and storage medium provided in this application utilize the voltage response characteristics of the charging process itself. Through a staged charging strategy, the battery enters a near-quasi-static state, effectively reducing polarization interference and highlighting the abnormal voltage plateau caused by lithium plating. This is manifested as a continuous interval with a significantly reduced local slope on the voltage change curve. Furthermore, a dynamic judgment mechanism based on cell group statistics is introduced. By analyzing the distribution characteristics of the voltage change rate over time, outlier behaviors deviating from the normal range are identified, avoiding the impact of individual differences on the reliability of the judgment.

[0056] Example 2 Based on the same technical concept as Embodiment 1 above, this application provides a non-destructive testing system for abnormal lithium plating in batteries. Figure 7 This is a schematic diagram of the non-destructive testing system for abnormal lithium plating in batteries provided in this application embodiment, as shown below. Figure 7 As shown, the battery abnormal lithium plating non-destructive testing system 200 includes: The charging execution module 210 is used to perform two-stage charging on the target battery. In the first charging stage, the target battery is charged to the charging cutoff voltage. After a preset resting time, the second charging stage begins. In the second charging stage, the target battery is recharged to the charging cutoff voltage with the target charging current. The minimum charging current in the first charging stage is greater than the target charging current.

[0057] The parameter acquisition module 220 is used to acquire the voltage change curves of each cell in the target battery during the second charging stage.

[0058] The parameter calculation module 230 is used to calculate the rate of change of voltage of each cell over time based on the voltage change curve, and obtain the rate of change of voltage curve.

[0059] The lithium plating detection module 240 is used to identify abnormal lithium plating cells based on outlier changes in the voltage change rate curves of each cell.

[0060] The battery abnormal lithium plating non-destructive testing system provided in this application embodiment requires no additional hardware, does not damage the battery structure, and does not rely on delayed steps such as resting or discharging during the entire testing process. It achieves true real-time online, low-cost, and highly robust early warning of lithium plating risks, significantly improving the safety management level of secondary utilization and the entire life cycle of automotive batteries.

[0061] It is understood that the implementation method of the non-destructive testing method for abnormal lithium plating in battery in Embodiment 1 above is also applicable to this embodiment and can achieve the same technical effect, so it will not be described again here.

[0062] Example 3 Based on the same concept, this application also provides an electronic device. Figure 8This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application, such as... Figure 8 As shown, the electronic device 300 may include: a processor 310, a communication interface 320, a memory 330, and a communication bus 340, wherein the processor 310, the communication interface 320, and the memory 330 communicate with each other via the communication bus 340. The processor 310 can call logical instructions in the memory 330 to execute the steps of the non-destructive testing method for abnormal lithium plating in batteries as described in the above embodiments. For example, this includes: S100. Perform two-stage charging on the target battery. In the first charging stage, the target battery is charged to the charging cutoff voltage. After a preset resting time, the second charging stage begins. In the second charging stage, the target battery is recharged to the charging cutoff voltage with the target charging current. The minimum charging current in the first charging stage is greater than the target charging current. S200: Obtain the voltage change curves of each cell in the target battery during the second charging stage. S300. Calculate the rate of change of voltage of each cell over time based on the voltage change curve, and obtain the rate of change of voltage curve. S400. Identify abnormal lithium-plating cells based on outlier changes in the voltage change rate curves of each cell.

[0063] The processor 310 can be a central processing unit (CPU). The processor can also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or combinations of the above types of chips.

[0064] Furthermore, the logical instructions in the aforementioned memory 330 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0065] The memory 330 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created by the processor, etc. Furthermore, the memory may include high-speed random access memory and non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory may optionally include memory remotely located relative to the processor, which can be connected to the processor via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0066] Example 4 Based on the same concept, embodiments of this application also provide a computer-readable storage medium storing a computer program containing at least one piece of code executable by a master control device to control the master control device to implement the steps of the non-destructive testing method for abnormal lithium plating in batteries as described in the above embodiments. For example, it includes: S100. Perform two-stage charging on the target battery. In the first charging stage, the target battery is charged to the charging cutoff voltage. After a preset resting time, the second charging stage begins. In the second charging stage, the target battery is recharged to the charging cutoff voltage with the target charging current. The minimum charging current in the first charging stage is greater than the target charging current. S200: Obtain the voltage change curves of each cell in the target battery during the second charging stage. S300. Calculate the rate of change of voltage of each cell over time based on the voltage change curve, and obtain the rate of change of voltage curve. S400. Identify abnormal lithium-plating cells based on outlier changes in the voltage change rate curves of each cell.

[0067] Based on the same technical concept, this application also provides a computer program, which, when executed by a main control device, is used to implement the above-described method embodiments.

[0068] The computer program may be stored, in whole or in part, on a computer-readable storage medium packaged with the processor, or in part or in whole on a memory not packaged with the processor.

[0069] Based on the same technical concept, this application also provides a processor for implementing the above-described method embodiments. The processor can be a chip.

[0070] In summary, the non-destructive testing method, system, electronic device, and storage medium for abnormal lithium plating in batteries provided in this application utilize the voltage response characteristics of the charging process itself. Through a staged charging strategy, the battery enters a near-quasi-static state, effectively reducing polarization interference and highlighting the abnormal voltage plateau caused by lithium plating. This is manifested as a continuous interval with a significantly reduced local slope on the voltage change curve. Furthermore, a dynamic judgment mechanism based on cell group statistics is introduced. By analyzing the distribution characteristics of the voltage change rate over time, outlier behaviors deviating from the normal range are identified, avoiding the impact of individual differences on the reliability of the judgment. The entire detection process requires no additional hardware, does not damage the battery structure, and does not rely on lag stages such as resting or discharging. It achieves truly real-time, low-cost, and highly robust early warning of lithium plating risks, significantly improving the safety management level of secondary use and the entire life cycle of automotive batteries.

[0071] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0072] The embodiments described above are merely examples of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A non-destructive testing method for abnormal lithium plating in batteries, characterized in that, The method includes: The target battery is charged in two stages. In the first charging stage, the target battery is charged to the charging cutoff voltage. After a preset resting time, the second charging stage begins. In the second charging stage, the target battery is recharged to the charging cutoff voltage with the target charging current. The minimum charging current in the first charging stage is greater than the target charging current. Obtain the voltage change curves of each cell in the target battery during the second charging stage; Calculate the rate of change of voltage of each cell over time based on the voltage change curve to obtain the rate of change of voltage curve; Abnormal lithium plating cells are identified based on outliers in the voltage change rate curves of each cell.

2. The non-destructive testing method for abnormal lithium plating in batteries according to claim 1, characterized in that, The step of identifying abnormal lithium-plating cells based on outlier variations in the voltage change rate curves of each cell includes: Calculate the target confidence interval for the voltage change rate of all cells at each voltage value based on the voltage change rate curve; The lower limit of the target confidence interval is used as the outlier threshold of the voltage change rate; If the voltage change rate of a target cell is consistently less than the outlier threshold within a continuous voltage range, then the target cell is identified as an abnormal lithium plating cell.

3. The non-destructive testing method for abnormal lithium plating in batteries according to claim 2, characterized in that, The length of the continuous voltage interval is greater than or equal to 10. mV The target confidence interval is a 95% confidence interval.

4. The non-destructive testing method for abnormal lithium plating in batteries according to claim 1, characterized in that, The step of identifying abnormal lithium-plating cells based on outlier variations in the voltage change rate curves of each cell includes: Calculate the average voltage change rate of all cells at each voltage value based on the voltage change rate curve. The outlier threshold of the voltage change rate is determined based on the average value; If the voltage change rate of a target cell is consistently less than the outlier threshold within a continuous voltage range, then the target cell is identified as an abnormal lithium plating cell.

5. The non-destructive testing method for abnormal lithium plating in batteries according to claim 4, characterized in that, The length of the continuous voltage interval is greater than or equal to 10. mV The outlier threshold is 75% of the average value.

6. The non-destructive testing method for abnormal lithium plating in batteries according to claim 1, characterized in that, The step of obtaining the voltage change curves of each cell in the target battery during the second charging stage includes: The cell voltage of each cell in the target battery is collected at preset time intervals during the second charging stage. The voltage change curves of each cell are constructed based on the preset time interval and the cell voltage.

7. The non-destructive testing method for abnormal lithium plating in batteries according to claim 1, characterized in that, The target charging current is less than or equal to 0.1C, and the preset resting time is less than or equal to 30 minutes.

8. A non-destructive testing system for abnormal lithium plating in batteries, characterized in that, The system includes: The charging execution module is used to perform two-stage charging on the target battery. In the first charging stage, the target battery is charged to the charging cutoff voltage. After a preset resting time, the second charging stage is entered. In the second charging stage, the target battery is recharged to the charging cutoff voltage with a target charging current. The minimum charging current in the first charging stage is greater than the target charging current. The parameter acquisition module is used to acquire the voltage change curves of each cell in the target battery during the second charging stage; The parameter calculation module is used to calculate the rate of change of voltage of each cell over time based on the voltage change curve, and obtain the rate of change of voltage curve. The lithium plating detection module is used to identify abnormal lithium plating cells based on outlier changes in the voltage change rate curves of each cell.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, The processor executes the computer program to implement the non-destructive testing method for abnormal lithium plating in batteries as described in any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the non-destructive testing method for abnormal lithium plating in batteries as described in any one of claims 1-7.

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