Lithium precipitation detection method and device of battery, electronic equipment and storage medium

Abstract

The application provides a lithium precipitation detection method and device of a battery, electronic equipment and a storage medium. The method comprises the following steps: acquiring a voltage difference of a battery to be detected during a relaxation period after each charging in a charging and discharging cycle; the relaxation period refers to a time period from the completion of charging to the recovery of the battery to be detected to a steady state; the voltage difference during the relaxation period is a difference between a voltage corresponding to the completion of charging of the battery to be detected and a voltage of the recovery of the battery to be detected to the steady state; and lithium precipitation detection is performed on the battery to be detected based on the voltage difference during the relaxation period corresponding to multiple charging and discharging cycles. According to the application, the voltage of two points during the relaxation period after the completion of each charging is collected, the voltage difference is calculated based on the voltage of the two points, and then lithium precipitation detection is performed on the battery to be detected according to the change of the voltage difference in the multiple charging and discharging cycles. The amount of data collected is small, and thus the calculation amount is reduced.

Description

Technical Field

[0001] This application relates to the field of battery testing technology, and more specifically, to a method, apparatus, electronic device, and storage medium for detecting lithium plating in batteries. Background Technology

[0002] Lithium plating in lithium batteries refers to the deposition and detachment of lithium ions on the electrodes during the charging and discharging process. This process may result in the formation of metallic lithium deposits, also known as "lithium dendrites," which can lead to a decrease in battery performance and increase safety risks.

[0003] Currently, the detection of lithium plating in lithium batteries mostly employs the voltage relaxation method. This involves cycling the lithium battery through charge and discharge cycles, recording the voltage during the relaxation process after each charge cycle, and obtaining a voltage-time curve. Differentiating this voltage-time curve yields the U'-time curve. If an inflection point exists in the U'-time curve, it indicates that lithium plating occurred when the battery was charged to a set state of charge (SOC) under specific conditions. This method requires collecting multiple voltage values ​​for a single charge-discharge cycle and analyzing voltage changes to determine whether lithium plating has occurred; therefore, it involves a significant computational load. Summary of the Invention

[0004] The purpose of this application is to provide a method, apparatus, electronic device, and storage medium for detecting lithium plating in batteries, thereby reducing the computational load while achieving lithium plating detection in batteries.

[0005] In a first aspect, embodiments of this application provide a method for detecting lithium plating in a battery, comprising:

[0006] The voltage difference during the relaxation period after each charge is completed in the charge-discharge cycle of the battery under test is obtained. The relaxation period refers to the time from the completion of charging to the recovery to steady state of the battery under test. The voltage difference during the relaxation period is the difference between the voltage at the completion of charging and the voltage at the recovery to steady state of the battery under test.

[0007] Lithium plating detection is performed on the battery under test based on the voltage difference during the relaxation period corresponding to multiple charge-discharge cycles.

[0008] This application embodiment collects the voltage at two points during the relaxation period after each charge is completed, calculates the voltage difference between the two points, and then performs lithium plating detection on the battery under test based on the change of the voltage difference during multiple charge-discharge cycles. The amount of data collected is relatively small, thereby reducing the amount of calculation.

[0009] In any embodiment, lithium plating detection is performed on the battery under test based on the voltage difference during the relaxation period corresponding to multiple charge-discharge cycles, including:

[0010] Based on the voltage difference corresponding to multiple charge-discharge cycles, a curve showing the change of voltage difference with the number of cycles is generated.

[0011] When the change in voltage difference is greater than or equal to a preset threshold, it is determined that lithium plating has occurred in the battery under test, and the number of cycles corresponding to the occurrence of lithium plating is recorded.

[0012] In this embodiment, since the battery is in different lithium plating stages, it will be reflected on the voltage change curve. Therefore, the degree of lithium plating and the corresponding charge-discharge cycle number can be intuitively determined through the voltage change curve.

[0013] In any embodiment, the preset threshold includes a first preset threshold and a second preset threshold, wherein the first preset threshold is less than the second preset threshold;

[0014] When the change in voltage difference is greater than or equal to the first preset threshold, the amount of lithium plating in the battery under test is determined to be the first degree of lithium plating.

[0015] When the change in voltage difference is greater than or equal to the second preset threshold, the amount of lithium plating in the battery under test is determined to be the second degree of lithium plating.

[0016] The degree of lithium plating in the first stage is less than that in the second stage.

[0017] In this embodiment, because the battery undergoes significant lithium plating, the corresponding lithium stripping and reintercalation reactions reach equilibrium. The voltage difference represents a mixture of the two reactions, thus significantly increasing the voltage difference. Furthermore, the degree of lithium plating also increases with the increase in voltage difference. Therefore, by determining whether the change in voltage difference exceeds a preset threshold, the accuracy of detecting significant lithium plating can be improved.

[0018] In any embodiment, the change in voltage difference is determined to be greater than a preset threshold by at least one of the following:

[0019] The voltage difference between two consecutive charge-discharge cycles is greater than a preset difference.

[0020] A voltage difference curve is generated based on the voltage difference corresponding to multiple charge-discharge cycles, and the slope of the voltage difference curve is greater than a preset slope.

[0021] The differential calculation is performed based on the voltage difference corresponding to multiple charge-discharge cycles, and the obtained differential value is greater than the preset differential value.

[0022] The embodiments of this application can improve the accuracy of detecting whether a large amount of lithium plating has occurred by judging whether the change in voltage difference is greater than a preset threshold.

[0023] In any embodiment, obtaining the voltage difference during the relaxation period after each charge completion in the battery under test during a charge-discharge cycle includes:

[0024] Charge the battery under test until the state of charge of the battery under test reaches the preset state of charge, and record the first voltage of the battery under test after charging is completed.

[0025] After the battery under test is fully charged, let it rest for a preset time and record the second voltage of the battery under test after resting.

[0026] The voltage difference during relaxation is determined based on the voltage difference between the first voltage and the second voltage.

[0027] In this embodiment, the voltage difference between two points is calculated after each charging cycle. The lithium plating detection of the battery under test is performed by analyzing the changes in the voltage difference corresponding to multiple charge-discharge cycles. Therefore, the amount of data collected is small, thereby reducing the computational load.

[0028] In any embodiment, charging the battery under test so that the state of charge of the charged battery reaches a preset state of charge includes:

[0029] The battery under test is charged with constant current until the voltage of the battery under test reaches the charging cutoff voltage after constant current charging.

[0030] The battery under test is charged with constant current and then charged with constant voltage to achieve a preset state of charge.

[0031] This application embodiment reduces the influence of internal battery polarization by first charging to the cutoff voltage with constant current and then charging with constant voltage, thereby enabling the battery under test to reach the preset state of charge and improving the accuracy of lithium plating detection.

[0032] In any embodiment, the preset duration ranges from [10 minutes, 60 minutes].

[0033] In this embodiment, if the resting time is too short, the battery under test will not reach a steady state, affecting the accuracy of lithium plating detection; if the resting time is too long, the battery under test will be stored at a high SOC, leading to performance degradation. Therefore, this application improves the accuracy of lithium plating detection and reduces damage to the battery under test by presetting a reasonable resting time.

[0034] In any embodiment, the method further includes:

[0035] After determining that the lithium plating level of the battery under test is the first degree of lithium plating, a water drop warning signal is output.

[0036] In this embodiment, after determining that the lithium plating amount of the battery under test has reached the first lithium plating level, a water drop warning signal is output. Since reaching the first lithium plating level indicates that the battery is in a state of large-scale lithium plating, continued use of the battery may lead to danger. Therefore, outputting a water drop warning signal serves as a warning, and the timing of the warning is quite reasonable.

[0037] In any embodiment, the method further includes:

[0038] Collect the charge and discharge parameters of the battery under test; the charge and discharge parameters include charge and discharge rate, rest time and SOC corresponding to the completion of charge and discharge;

[0039] Input the charge and discharge parameters into the lithium plating prediction model to obtain the number of charge and discharge cycles at which the battery under test exhibits the first degree of lithium plating, as output by the lithium plating prediction model.

[0040] The lithium plating prediction model was trained using the following method:

[0041] The test battery was charged and discharged using various different charging and discharging parameters, and the training voltage difference during the relaxation period after each charge was completed was obtained.

[0042] The number of charge-discharge cycles corresponding to the first degree of lithium plating in the test battery is determined based on the training voltage difference.

[0043] The model is trained by using charge and discharge parameters as input and the number of charge and discharge cycles as labels to obtain a lithium plating prediction model.

[0044] This application embodiment analyzes charge and discharge parameters through a lithium plating prediction model, and introduces an artificial intelligence model to improve the accuracy and efficiency of lithium plating prediction.

[0045] In any embodiment, the method further includes:

[0046] Acquire information on battery temperature and internal pressure during the relaxation period after each charge cycle of the battery under test.

[0047] Lithium plating detection of the battery under test is performed based on the voltage difference during the relaxation period corresponding to multiple charge-discharge cycles, including:

[0048] The voltage difference is compared with a first voltage threshold to obtain a first comparison result;

[0049] The battery temperature is compared with a temperature threshold to obtain a second comparison result;

[0050] The internal pressure information of the battery is compared with the pressure threshold to obtain a third comparison result;

[0051] The lithium deposition amount is determined based on the first comparison result, the second comparison result, and the third comparison result to determine whether the battery under test has reached the first degree of lithium deposition.

[0052] This application's embodiments improve the accuracy of lithium plating level detection by combining voltage difference, battery temperature, and internal battery pressure to determine whether the lithium plating level of the battery under test has reached the first lithium plating level.

[0053] Secondly, embodiments of this application provide a lithium plating detection device for batteries, comprising:

[0054] The voltage difference acquisition module is used to acquire the voltage difference of the battery under test during the relaxation period after each charge is completed during the charge and discharge cycle. The relaxation period refers to the time period from the completion of charging to the recovery to steady state of the battery under test. The voltage difference during the relaxation period is the difference between the voltage corresponding to the completion of charging and the voltage at which the battery under test recovers to steady state.

[0055] The detection module is used to detect lithium plating in the battery under test based on the voltage difference during the relaxation period corresponding to multiple charge-discharge cycles.

[0056] Thirdly, embodiments of this application provide an electronic device, including: a processor, a memory, and a bus, wherein,

[0057] The processor and memory communicate with each other via a bus;

[0058] The memory stores program instructions that can be executed by the processor, and the processor can execute the method of the first aspect by calling the program instructions.

[0059] Fourthly, embodiments of this application provide a non-transitory computer-readable storage medium, comprising:

[0060] A non-transitory computer-readable storage medium stores computer instructions that cause the computer to perform the method of the first aspect.

[0061] Fifthly, embodiments of this application provide a computer program product, including computer program instructions, which, when read and executed by a processor, perform the method of the first aspect.

[0062] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing embodiments of this application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings. Attached Figure Description

[0063] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application 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.

[0064] Figure 1 A schematic flowchart of a lithium plating detection method for batteries provided in this application embodiment;

[0065] Figure 2 A capacity retention curve is provided for an embodiment of this application;

[0066] Figure 3 A voltage difference curve is provided for an embodiment of this application;

[0067] Figure 4 A schematic diagram of a lithium plating detection device for a battery provided in an embodiment of this application;

[0068] Figure 5 This is a schematic diagram of the physical structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0069] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0070] 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 pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0071] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0072] 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.

[0073] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0074] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0075] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0076] Lithium-ion batteries, as a green energy source, have advantages such as high voltage, high energy density, and no memory effect. They have developed rapidly in recent years and have been widely used in many fields.

[0077] Lithium plating is an abnormal phenomenon that easily occurs in lithium-ion batteries during charging, especially under fast charging or low-temperature charging conditions. When the battery potential of graphite is lower than the electrode potential of lithium, lithium ions accumulate on the graphite surface and cannot intercalate in time, resulting in lithium plating. Lithium plating not only accelerates capacity decay and shortens battery life, but the deposited lithium may also puncture the battery separator, causing a short circuit and leading to safety issues. All of these factors accelerate the aging of lithium-ion batteries, leading to reduced battery performance and even more serious consequences. Therefore, to ensure normal battery use and reduce risks, it is necessary to detect lithium plating in batteries in a timely manner and provide early warnings of potential aging.

[0078] Currently, the voltage relaxation method is used to detect lithium plating in batteries. This method requires collecting a large amount of voltage data during the relaxation process after each charge and discharge cycle, and then differentiating the collected voltage data to determine whether lithium plating has occurred. This method requires collecting a lot of data for each cycle, increasing the computational load.

[0079] To address the aforementioned technical problems, embodiments of this application provide a method, apparatus, electronic device, and storage medium for detecting lithium plating in batteries. This lithium plating detection method acquires the voltage difference during the relaxation period after each charge cycle and detects the lithium plating status of the battery under test based on the voltage differences corresponding to multiple charge-discharge cycles. Therefore, this application only requires collecting the voltage at two points during the relaxation period, significantly reducing the amount of voltage data collected and the computational load.

[0080] It should be noted that the embodiments of this application can perform lithium plating detection on lithium-ion cells or batteries containing lithium-ion cells. For ease of description, the embodiments of this application refer to cells and batteries containing cells collectively as batteries under test.

[0081] It is understood that the lithium plating detection method for batteries provided in this application embodiment can be applied to electronic devices, which include terminals and servers; wherein the terminal can specifically be a smartphone, tablet computer, computer, personal digital assistant (PDA), etc.; the server can specifically be an application server or a web server.

[0082] Figure 1 This is a schematic flowchart of a lithium plating detection method for batteries provided in an embodiment of this application, as shown below. Figure 1 As shown, the method includes:

[0083] Step 101: Obtain the voltage difference during the relaxation period after each charge is completed in the charge-discharge cycle of the battery under test; the relaxation period refers to the time period from the completion of charging to the recovery to steady state of the battery under test; the voltage difference during the relaxation period is the difference between the voltage corresponding to the completion of charging and the voltage at which the battery under test recovers to steady state.

[0084] Step 102: Lithium plating detection is performed on the battery under test based on the voltage difference during the relaxation period corresponding to multiple charge-discharge cycles.

[0085] In the specific implementation process, the battery under test can be a brand-new battery that has not yet been used, a battery that has been used for a period of time, or a retired battery, etc. During the lithium plating detection of the battery under test, a charge-discharge device can be used to perform charge-discharge cycles on the battery. This charge-discharge device can be an electrochemical workstation, etc.

[0086] Since lithium plating typically occurs during battery charging, a voltage acquisition device can be used to collect the voltage difference during the relaxation period after the battery under test has completed one charge. It should be noted that the battery under test exhibits internal polarization after charging, referred to as the polar state in this embodiment. By allowing the battery to rest, this internal polarization can be reduced, allowing the battery to reach a steady state or near-steady state. Therefore, the time it takes for the battery under test to transition from the polar state to the steady state or near-steady state is called the relaxation period. Thus, the voltage difference during the relaxation period can be the difference between the voltage of the battery under test after charging and the voltage at which it recovers to its steady state.

[0087] During the charge-discharge cycle of the battery under test, the voltage difference can be obtained using the method described above after each charge. Alternatively, the voltage difference can be obtained discontinuously, meaning that the voltage difference can be obtained once every few charge-discharge cycles. Therefore, multiple voltage differences can be obtained. Subsequently, lithium plating detection is performed on the battery under test based on the changes in these multiple voltage differences. The degree of lithium plating and the corresponding number of charge-discharge cycles can be determined through lithium plating detection.

[0088] This application embodiment collects the voltage at two points during the relaxation period after each charge is completed, calculates the voltage difference between the two points, and then performs lithium plating detection on the battery under test based on the change of the voltage difference during multiple charge-discharge cycles. The amount of data collected is relatively small, thereby reducing the amount of calculation.

[0089] Based on the above embodiments, lithium plating detection is performed on the battery under test based on the voltage difference during the relaxation period corresponding to multiple charge-discharge cycles, including:

[0090] Based on the voltage difference corresponding to multiple charge-discharge cycles, a curve showing the change of voltage difference with the number of cycles is generated.

[0091] When the change in voltage difference is greater than or equal to a preset threshold, it is determined that lithium plating has occurred in the battery under test, and the number of cycles corresponding to the occurrence of lithium plating is recorded.

[0092] In the specific implementation process, during the relaxation period after the battery under test completes charging, the battery under test recovers from the polar state to the steady state. During the relaxation period, lithium ions in the battery under test are embedded in the graphite interlayer to form LixC6 or lithium is deposited to form lithium metal. The open circuit voltage of LixC6 is 93mV and the open circuit voltage of lithium metal is 7.7mV. The potential difference between LixC6 and lithium metal causes some lithium to discharge and become lithium ions, which are then re-embedded in the graphite. Therefore, the lithium plating phenomenon of the battery under test can be analyzed in three stages after multiple charge-discharge cycles: 1. No or little lithium plating: If the amount of lithium plating is small, the lithium stripping current is lower than the lithium reintercalation current in graphite, and lithium ion intercalation is the main process. The relaxation voltage is dominated by the open-circuit voltage of LixC6. At this time, the voltage change during relaxation is small, that is, the voltage difference is small; 2. Accumulated lithium plating, large amount of lithium plating: As the lithium stripping and lithium reintercalation reactions reach equilibrium, the relaxation voltage shows a mixed voltage of the two reactions, indicating that lithium plating and LixC6 coexist. At this time, the voltage change during relaxation increases, that is, the voltage difference suddenly increases; 3. Severe lithium plating: The relaxation voltage is dominated by the open-circuit voltage of lithium metal. At this time, the voltage difference during relaxation reaches its maximum value. Therefore, the voltage difference of the battery under test during relaxation varies in different stages of lithium plating.

[0093] To verify the above analysis, this application provides an experiment with a comparative example and an embodiment, wherein:

[0094] Comparative Example: After charging to the charging cutoff voltage under constant current (CC) charging at 1C, constant voltage charging is performed to 100% SOC, and the actual voltage ① is recorded. After resting for 10 minutes, the actual voltage ② is recorded. Then, discharge to the discharge cutoff voltage under 1C current (constant current discharge), and rest for 10 minutes to relax. This process is the charge-discharge procedure for each cycle.

[0095] Example: Except for the charge / discharge rate of 2C, the other conditions are the same as the comparative example.

[0096] The comparative examples and embodiments were charged and discharged in the manner described above, and the capacity retention rate corresponding to each charge-discharge cycle was recorded. A capacity retention rate change curve was generated based on the capacity retention rate and the corresponding number of cycles, as shown below. Figure 2 As shown, since the charge / discharge rate of the embodiment is larger than that of the comparative example, the embodiment experienced a sudden drop in capacity retention rate after about 600 cycles, indicating that the battery corresponding to the embodiment experienced a capacity drop.

[0097] During the charge-discharge cycle of the comparative examples and embodiments, the voltage difference during the relaxation period after each charge-discharge cycle can be recorded, and the recorded voltage difference and the corresponding number of cycles can be used to generate a voltage change curve, such as... Figure 3 As shown, the lithium plating status of the battery under test can be determined based on the voltage change curve. From Figure 3It can be seen that the test batteries corresponding to the comparative example and the embodiment both exhibited a sudden increase in voltage difference around 600 charge-discharge cycles. Therefore, it can be determined that a large amount of lithium plating occurred in both types of test batteries around 600 charge-discharge cycles. Figure 3 and Figure 2 The experimental results are corresponding.

[0098] In addition to cases of significant lithium plating, the degree of lithium plating can also include cases of severe lithium plating. Severe lithium plating can be determined by the maximum voltage difference.

[0099] In this embodiment, since the battery is in different lithium plating stages, it will be reflected on the voltage change curve. Therefore, the degree of lithium plating and the corresponding charge-discharge cycle number can be intuitively determined through the voltage change curve.

[0100] Many non-destructive testing methods can determine the lithium plating initiation point of a battery under test. However, the impact of a small amount of lithium plating on battery performance cannot be directly determined and may be minor. Using the lithium plating initiation point to warn of performance deterioration may lead to over-warning. In actual battery use, a safety accident may only occur when lithium plating accumulates and forms lithium dendrites, eventually piercing the separator. Therefore, providing early warnings before this point is far more valuable.

[0101] Therefore, when performing lithium plating detection on a battery in this embodiment of the application, the preset threshold may include a first preset threshold and a second preset threshold, wherein the first preset threshold is less than the second preset threshold; when the change in voltage difference is greater than or equal to the first preset threshold, the amount of lithium plating on the battery under test is determined to be the first degree of lithium plating; when the change in voltage difference is greater than or equal to the second preset threshold, the amount of lithium plating on the battery under test is determined to be the second degree of lithium plating; wherein the first degree of lithium plating is less than the second degree of lithium plating.

[0102] In practical implementation, when judging the degree of lithium plating, the voltage difference can be compared with a preset threshold. If the voltage difference is greater than or equal to the first preset threshold, it is determined that the lithium plating of the battery under test has reached the first degree of lithium plating. The first degree of lithium plating is used to characterize a large amount of lithium plating, that is, the lithium plating of the battery under test has accumulated into lithium dendrites. If it continues to be used, there is a risk of puncturing the separator. Therefore, in practical applications, if the lithium plating degree of the battery under test is detected to have reached the first degree of lithium plating, an alarm can be issued.

[0103] If the voltage difference is greater than or equal to the second preset threshold, the lithium plating amount of the battery under test is determined to have reached the second degree of lithium plating. The second degree of lithium plating is used to characterize severe lithium plating and is greater than the first degree of lithium plating, meaning that the lithium plating amount of the battery under test has reached the limit value for puncturing the separator and is about to puncture the separator.

[0104] The embodiments of this application can identify the locations where a large amount of lithium plating and severe lithium plating occur in the battery under test. Therefore, in order to improve battery safety, the detection of the degree of lithium plating in the battery under test provides a basis for more timely alarms.

[0105] like Figure 3 As shown, based on the voltage change curve, the point where the voltage difference suddenly increases can be determined. Specifically, it can be determined whether the change in voltage difference is greater than a preset threshold. If it is greater than the preset threshold, it indicates that the voltage difference has suddenly increased, and thus it can be determined that the battery under test has undergone the first degree of lithium plating.

[0106] When the voltage difference reaches its maximum value, it indicates that the relaxation voltage is dominated by the open-circuit voltage of lithium metal. At this time, the battery under test is in a state of severe lithium plating, namely the second degree of lithium plating.

[0107] In this embodiment of the application, since a large amount of lithium plating occurs in the battery, the corresponding lithium stripping and lithium reintercalation reactions reach equilibrium, and the voltage difference is a mixed voltage of the two reactions. Therefore, the voltage difference will increase significantly. Thus, by judging whether the change in voltage difference is greater than a preset threshold, the accuracy of detecting whether a large amount of lithium plating has occurred can be improved.

[0108] Based on the above embodiments, at least one of the following methods can be used to determine that the change in voltage difference is greater than a preset threshold:

[0109] 1. The voltage difference between two consecutive charge and discharge cycles is greater than the preset difference.

[0110] 2. A voltage difference curve is generated based on the voltage difference corresponding to multiple charge-discharge cycles, and the slope of the voltage difference curve is greater than a preset slope.

[0111] 3. The differential calculation is performed based on the voltage difference corresponding to multiple charge and discharge cycles, and the obtained differential value is greater than the preset differential value.

[0112] In the specific implementation process, each charge-discharge cycle corresponds to a voltage difference. A voltage change curve can be generated by combining the voltage difference corresponding to each charge-discharge cycle with the corresponding number of cycles, such as... Figure 3As shown, based on this voltage change curve, the voltage difference corresponding to the current charge / discharge cycle can be compared with the voltage difference corresponding to the previous charge / discharge cycle to obtain the difference value. If this difference value is greater than a preset difference value, it indicates that the voltage difference has suddenly increased, confirming that the battery under test has experienced a large amount of lithium plating. It should be noted that the minimum number of cycles corresponding to the sudden increase in voltage difference is the starting point for a large amount of lithium plating in the battery under test. Subsequently, as the battery under test continues to charge and discharge, the amount of lithium plating gradually increases. In addition, when the electronic device acquires the voltage difference during the relaxation period after charging is completed, it can acquire it at intervals. The interval number can be 1, 2, 5, 10, etc. The smaller the interval number, the more accurate the lithium plating detection of the battery under test, but the larger the computational load is; the larger the interval number, the smaller the computational load, but the lower the accuracy of lithium plating detection. The specific value of the interval number is not infinitely large; an upper limit can be given based on the actual situation, such as a maximum value of 50 or 100. Taking an interval of 10 as an example, the electronic device can obtain the voltage difference corresponding to the 10th, 20th, 30th, and so on charge-discharge cycles. The difference between the voltage difference corresponding to the 10th and 20th charge-discharge cycles is called the voltage difference between two adjacent charge-discharge cycles. Similarly, the difference between the voltage difference corresponding to the 20th and 30th charge-discharge cycles is called the voltage difference between two adjacent charge-discharge cycles.

[0113] After acquiring the voltage differences corresponding to multiple charge-discharge cycles, the electronic device generates a voltage difference curve based on multiple voltage differences and the number of cycles, such as... Figure 3 As shown, the slope of any point on the curve can be calculated. The minimum number of cycles corresponding to a slope greater than a preset slope is the starting point where a large amount of lithium plating occurs in the battery under test. Subsequently, as the battery continues to charge and discharge, the amount of lithium plating gradually increases.

[0114] Alternatively, differential calculations can be performed based on the voltage differences corresponding to each charge-discharge cycle to obtain the differential value corresponding to each cycle number. The minimum cycle number where the differential value is greater than a preset differential value is taken as the starting point for a large amount of lithium plating in the battery under test. Subsequently, as the battery under test continues to charge and discharge, the amount of lithium plating gradually increases.

[0115] The embodiments of this application can improve the accuracy of detecting whether a large amount of lithium plating has occurred by judging whether the change in voltage difference is greater than a preset threshold.

[0116] Based on the above embodiments, the voltage difference during the relaxation period after each charge is completed in the battery under test during the charge-discharge cycle is obtained, including:

[0117] Charge the battery under test until the state of charge of the battery under test reaches the preset state of charge, and record the first voltage of the battery under test after charging is completed.

[0118] After the battery under test is fully charged, let it rest for a preset time and record the second voltage of the battery under test after resting.

[0119] The voltage difference of the battery under test during relaxation is determined based on the voltage difference between the first voltage and the second voltage.

[0120] In the specific implementation process, the battery under test is charged using a charging and discharging device until the battery's state of charge (SOC) reaches a preset SOC. The preset SOC ranges from 0% to 100%, preferably from 50% to 100%. This embodiment uses a preset SOC of 100% as an example. After charging the battery to 100% SOC, charging is stopped, and the first voltage of the battery at that time is recorded. Then, the battery is allowed to rest for a preset time. After the preset time, the second voltage of the battery is recorded. The preset time ranges from 10 minutes to 60 minutes, preferably from 10 minutes to 30 minutes. In this application embodiment, the period during which the battery under test is placed in a resting state is referred to as the relaxation period. During this period, the battery recovers from its polar state to a steady state or near-steady state. It should be noted that the preset duration should not be too short or too long. If the preset duration is too short, the battery under test will not reach a steady state or near-steady state, resulting in inaccurate second voltage detection and affecting subsequent lithium plating detection. If the preset duration is too long, the battery under test will be stored at a high SOC for a long time, causing battery performance to deteriorate. In addition, the time required for the battery under test to reach a steady state after charging is completed is affected by factors such as charging rate, temperature, and battery aging degree. For example, the higher the charging rate, the longer it takes for the battery under test to recover to a steady state. Therefore, the preset duration can be determined based on factors such as the charging rate, temperature, and battery aging degree of the battery under test.

[0121] After obtaining the first voltage and the second voltage, the voltage difference between the first voltage and the second voltage is calculated, and the calculated voltage difference is used as the voltage difference of the battery under test during the relaxation period.

[0122] This application embodiment calculates the voltage difference between two points after each charging cycle and detects lithium plating in the battery under test by analyzing the changes in the voltage difference across multiple charge-discharge cycles. Therefore, the amount of data collected is relatively small, thereby reducing the computational load.

[0123] Based on the above embodiments, the battery under test is charged so that the state of charge of the charged battery reaches a preset state of charge, including:

[0124] The battery under test is charged with constant current until the voltage of the battery under test reaches the cutoff voltage after constant current charging.

[0125] The battery under test is charged with constant current and then charged with constant voltage to achieve a preset state of charge.

[0126] In practical implementation, when charging the battery under test, constant current charging can be performed first. For example, a constant current charging rate of 1C can be used to charge the battery under test until its voltage reaches the cutoff voltage. It can be understood that the cutoff voltage refers to the voltage corresponding to the preset state of charge (SOC) that the battery under test should achieve. After the battery under test reaches the cutoff voltage during constant current charging, its actual voltage is lower than the cutoff voltage due to internal polarization, indicating that the actual SOC of the charged battery has not reached the preset SOC. Therefore, constant voltage charging can be performed on the battery after constant current charging to bring the SOC of the charged battery to the preset SOC.

[0127] Alternatively, the battery under test can be charged with a small, constant current to bring it to a preset state of charge (SOC). Because of the small current, the internal polarization reaction of the battery is minimal and can be ignored. Constant voltage charging can also be used to achieve the same preset SOC.

[0128] This application embodiment reduces the influence of internal battery polarization by first charging to the cutoff voltage with constant current and then charging with constant voltage, thereby enabling the battery under test to reach the preset state of charge and improving the accuracy of lithium plating detection.

[0129] Based on the above embodiments, the method further includes:

[0130] Collect the charge and discharge parameters of the battery under test; the charge and discharge parameters include charge and discharge rate, rest time and SOC corresponding to the completion of charge and discharge;

[0131] Input the charge and discharge parameters into the lithium plating prediction model to obtain the number of charge and discharge cycles at which the battery under test exhibits the first degree of lithium plating, as output by the lithium plating prediction model.

[0132] In the specific implementation process, the lithium plating prediction model is pre-trained, and its training method is as follows:

[0133] The test battery was charged and discharged using various different charging and discharging parameters, and the training voltage difference during the relaxation period after each charge was obtained. These charging and discharging parameters may include the charging rate, discharging rate, rest time after each charge, and the state of charge (SOC) corresponding to each charge completion. It should be noted that the training voltage difference is similar to the voltage difference in the above embodiments, only the corresponding battery is different; this will not be elaborated further here.

[0134] The number of charge-discharge cycles corresponding to the first degree of lithium plating in the test battery is determined based on the training voltage difference. It should be noted that the method for determining whether the lithium plating has reached the first degree of lithium plating based on the training voltage difference can be found in the above embodiment, which is a method for determining whether the lithium plating has reached the first degree of lithium plating based on the voltage difference, and will not be repeated here.

[0135] The model is trained by using charge and discharge parameters as input and the number of charge and discharge cycles as labels to obtain a lithium plating prediction model.

[0136] After obtaining the lithium plating prediction model, for the battery under test, charge and discharge parameters of the battery under test can be collected, and then the charge and discharge parameters can be input into the trained lithium plating prediction model to obtain the number of charge and discharge cycles at which the battery under test exhibits the first degree of lithium plating, as output by the lithium plating prediction model.

[0137] This application embodiment analyzes charge and discharge parameters through a lithium plating prediction model, and introduces an artificial intelligence model to improve the accuracy and efficiency of lithium plating prediction.

[0138] Based on the above embodiments, the method further includes:

[0139] Acquire information on battery temperature and internal pressure during the relaxation period after each charge cycle of the battery under test.

[0140] Lithium plating detection of the battery under test is performed based on the voltage difference during the relaxation period corresponding to multiple charge-discharge cycles, including:

[0141] The voltage difference is compared with a first voltage threshold to obtain a first comparison result;

[0142] The battery temperature is compared with a temperature threshold to obtain a second comparison result;

[0143] The internal pressure information of the battery is compared with the pressure threshold to obtain a third comparison result;

[0144] The lithium deposition amount is determined based on the first comparison result, the second comparison result, and the third comparison result to determine whether the battery under test has reached the first degree of lithium deposition.

[0145] In practical implementation, lithium plating in batteries can be determined not only by the voltage difference during the relaxation period after each charge, but also by the battery's temperature and internal pressure. Specifically, the battery temperature and internal pressure information can be obtained during the relaxation period after each charge cycle. The battery temperature can be the average temperature, the maximum temperature, or an intermediate value during the relaxation period. The internal pressure information can be the average pressure, the maximum pressure, or an intermediate value during the relaxation period.

[0146] For voltage difference, battery temperature, and internal battery pressure, corresponding thresholds are used for comparison. Specifically, the voltage difference is compared to a first voltage threshold to obtain a first comparison result; if the voltage difference is greater than the first voltage threshold, the battery under test can be preliminarily considered to have exhibited a first degree of lithium plating. The battery temperature is compared to a temperature threshold to obtain a second comparison result; if the battery temperature is greater than the temperature threshold, the battery under test can be preliminarily considered to have exhibited a first degree of lithium plating. The internal battery pressure information is compared to a pressure threshold to obtain a third comparison result; if the internal battery pressure information is greater than the pressure threshold, the battery under test can be preliminarily considered to have exhibited a first degree of lithium plating. The first voltage threshold, temperature threshold, and pressure threshold can all be set according to actual conditions.

[0147] After obtaining the first, second, and third comparison results, if two or more comparison results indicate that the tested battery has reached the first level of lithium plating, then it can be finally determined that the tested battery has reached the first level of lithium plating. Otherwise, it indicates that the tested battery has not reached the first level of lithium plating. Alternatively, a weighted average can be calculated based on the first, second, and third comparison results to obtain a score indicating that the tested battery has reached the first level of lithium plating. If the score is higher than a preset score, then it is determined that the tested battery has reached the first level of lithium plating. The weights corresponding to each comparison result can be set according to the actual situation.

[0148] This application's embodiments improve the accuracy of lithium plating level detection by combining voltage difference, battery temperature, and internal battery pressure to determine whether the lithium plating level of the battery under test has reached the first lithium plating level.

[0149] This application provides a comparative example and six embodiments of a lithium plating detection process, wherein:

[0150] Comparative Example: After charging to the charging cutoff voltage under constant current (CC) charging at 1C, constant voltage charging is performed to 100% SOC, and the actual voltage ① is recorded. After resting for 10 minutes, the actual voltage ② is recorded. Then, discharge to the discharge cutoff voltage under 1C current (constant current discharge), and rest for 10 minutes to relax. This process is the charge-discharge procedure for each cycle.

[0151] Example 1: Except for the charge / discharge rate of 2C, the other conditions are the same as those in the comparative example.

[0152] Example 2: Except for the charge / discharge rate of 0.5C, the other conditions are the same as those in the comparative example.

[0153] Example 3: Except for the settling time of 60 minutes, the other conditions were the same as those of the comparative example.

[0154] Example 4: Except for the settling time of 120 minutes, the other conditions were the same as those of the comparative example.

[0155] Example 5: Except for charging to 80% SOC, the other conditions are the same as in Example 1.

[0156] Example 6: Except for charging to 50% SOC, the other conditions are the same as in Example 1.

[0157] After charging and discharging the comparative example and the embodiment using the above method, the following results can be obtained:

[0158]

[0159] From the table above, we can conclude that:

[0160] By comparing Examples 1 and 2 with the comparative example, it is found that the higher the charging rate, the faster the battery ages (see the cycle corresponding to 85% SOH). In Example 1, a large amount of lithium plating occurred after about 600 cycles, and the battery experienced a drop in voltage at this time, indicating that the sudden increase in voltage during charging can provide a voltage drop warning.

[0161] By comparing Examples 3 and 4 with the comparative examples, the effect of resting time on charge-discharge cycles is illustrated. That is, excessive resting time will lead to a decrease in battery performance.

[0162] By comparing Examples 5 and 6 with the comparative examples, it is demonstrated that even at different SOC levels, a sudden increase in cycle energy during charging can still be used to achieve a low-voltage warning. Therefore, the embodiments of this application are applicable to lithium plating detection of batteries charged to (0, 100% SOC). In addition to charging the battery under test to 50% SOC and 100% SOC, the embodiments of this application also tested the battery under test at 10% SOC, 30% SOC, and 75% SOC, all of which achieved the purpose of lithium plating detection.

[0163] Figure 4 This is a schematic diagram of a lithium plating detection device for batteries provided in an embodiment of this application. This device can be a module, program segment, or code on an electronic device. It should be understood that this device is similar to the one described above. Figure 1 The method implementation corresponds to this and can be executed. Figure 1 The various steps involved in the method embodiment, and the specific functions of the device, can be found in the description above. To avoid repetition, detailed descriptions are appropriately omitted here. The device includes: a voltage difference acquisition module 401 and a detection module 402, wherein:

[0164] The voltage difference acquisition module 401 is used to acquire the voltage difference of the battery under test during the relaxation period after each charge is completed during the charge and discharge cycle. The relaxation period refers to the time period from the completion of charging to the recovery to steady state of the battery under test. The voltage difference during the relaxation period is the difference between the voltage corresponding to the completion of charging and the voltage at which the battery under test recovers to steady state.

[0165] The detection module 402 is used to detect lithium plating in the battery under test based on the voltage difference during the relaxation period corresponding to multiple charge-discharge cycles.

[0166] Based on the above embodiments, the detection module 402 is specifically used for:

[0167] Based on the voltage difference corresponding to multiple charge-discharge cycles, a curve showing the change of voltage difference with the number of cycles is generated.

[0168] When the change in voltage difference is greater than or equal to a preset threshold, it is determined that lithium plating has occurred in the battery under test, and the number of cycles corresponding to the occurrence of lithium plating is recorded.

[0169] Based on the above embodiments, the preset threshold includes a first preset threshold and a second preset threshold, wherein the first preset threshold is less than the second preset threshold; the detection module 402 is specifically used for:

[0170] When the change in voltage difference is greater than or equal to the first preset threshold, the amount of lithium plating in the battery under test is determined to be the first degree of lithium plating.

[0171] When the change in voltage difference is greater than or equal to the second preset threshold, the amount of lithium plating in the battery under test is determined to be the second degree of lithium plating.

[0172] The degree of lithium plating in the first stage is less than that in the second stage.

[0173] Based on the above embodiments, the change in voltage difference is determined to be greater than a preset threshold by at least one of the following:

[0174] The voltage difference between two consecutive charge-discharge cycles is greater than a preset difference.

[0175] A voltage difference curve is generated based on the voltage difference corresponding to multiple charge-discharge cycles, and the slope of the voltage difference curve is greater than the preset slope.

[0176] The differential calculation is performed based on the voltage difference corresponding to multiple charge-discharge cycles, and the obtained differential value is greater than the preset differential value.

[0177] Based on the above embodiments, the voltage difference acquisition module 401 is specifically used for:

[0178] Charge the battery under test until the state of charge of the battery under test reaches the preset state of charge, and record the first voltage of the battery under test after charging is completed.

[0179] After the battery under test is fully charged, let it rest for a preset time and record the second voltage of the battery under test after resting.

[0180] The voltage difference during relaxation is determined based on the voltage difference between the first voltage and the second voltage.

[0181] Based on the above embodiments, the voltage difference acquisition module 401 is specifically used for:

[0182] The battery under test is charged with constant current until the voltage of the battery under test reaches the charging cutoff voltage after constant current charging.

[0183] The battery under test is charged with constant current and then charged with constant voltage to achieve a preset state of charge.

[0184] Based on the above embodiments, the preset duration range is [10 minutes, 60 minutes].

[0185] Based on the above embodiments, the device further includes a warning module for:

[0186] After determining that the lithium plating level of the battery under test is the first degree of lithium plating, a water drop warning signal is output.

[0187] Based on the above embodiments, the device further includes a model analysis module, used for:

[0188] Collect the charging and discharging parameters of the battery under test; the charging and discharging parameters include the charging and discharging rate, resting time, and the SOC corresponding to the completion of charging and discharging respectively;

[0189] Input the charge and discharge parameters into the lithium plating prediction model to obtain the number of charge and discharge cycles at which the battery under test exhibits the first degree of lithium plating, as output by the lithium plating prediction model.

[0190] The lithium plating prediction model was trained using the following method:

[0191] The test battery was charged and discharged using various different charging and discharging parameters, and the training voltage difference during the relaxation period after each charge was completed was obtained.

[0192] The number of charge-discharge cycles corresponding to the first degree of lithium plating in the test battery is determined based on the training voltage difference.

[0193] The model is trained by using charge and discharge parameters as input and the number of charge and discharge cycles as labels to obtain a lithium plating prediction model.

[0194] Based on the above embodiments, the detection module 402 is further configured to:

[0195] Acquire information on battery temperature and internal pressure during the relaxation period after each charge cycle of the battery under test.

[0196] Lithium plating detection of the battery under test is performed based on the voltage difference during the relaxation period corresponding to multiple charge-discharge cycles, including:

[0197] The voltage difference is compared with a first voltage threshold to obtain a first comparison result;

[0198] The battery temperature is compared with a temperature threshold to obtain a second comparison result;

[0199] The internal pressure information of the battery is compared with the pressure threshold to obtain a third comparison result;

[0200] The lithium deposition amount is determined based on the first comparison result, the second comparison result, and the third comparison result to determine whether the battery under test has reached the first degree of lithium deposition.

[0201] Figure 5 This is a schematic diagram of the physical structure of the electronic device provided in the embodiments of this application, such as... Figure 5 As shown, the electronic device includes: a processor 501, a memory 502, and a bus 503; wherein,

[0202] The processor 501 and the memory 502 communicate with each other through the bus 503;

[0203] The processor 501 is used to call program instructions in the memory 502 to execute the methods provided in the above-described method embodiments, such as: obtaining the voltage difference during the relaxation period after each charge is completed in the charge-discharge cycle of the battery under test; the relaxation period refers to the time period from the completion of charging to the recovery to a steady state of the battery under test; the voltage difference during the relaxation period is the difference between the voltage corresponding to the completion of charging and the voltage after recovery to a steady state of the battery under test; and performing lithium plating detection on the battery under test based on the voltage difference during the relaxation period corresponding to multiple charge-discharge cycles.

[0204] Processor 501 can be an integrated circuit chip with signal processing capabilities. The processor 501 can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor.

[0205] The memory 502 may include, but is not limited to, random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), etc.

[0206] This embodiment discloses a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium. The computer program includes program instructions, and when the program instructions are executed by the computer, the computer can execute the methods provided in the above-described method embodiments, such as: acquiring the voltage difference during the relaxation period after each charge is completed in the charge-discharge cycle of the battery under test; the relaxation period refers to the time period from the completion of charging to the recovery to a steady state of the battery under test; the voltage difference during the relaxation period is the difference between the voltage corresponding to the completion of charging and the voltage after recovery to a steady state of the battery under test; and performing lithium plating detection on the battery under test based on the voltage difference during the relaxation period corresponding to multiple charge-discharge cycles.

[0207] This embodiment provides a non-transitory computer-readable storage medium storing computer instructions that cause the computer to execute the methods provided in the above-described method embodiments. For example, the instructions include: acquiring the voltage difference during the relaxation period after each charge cycle of the battery under test; the relaxation period refers to the time interval from the completion of charging to the recovery to a steady state of the battery under test; the voltage difference during the relaxation period is the difference between the voltage corresponding to the completion of charging and the voltage at which the battery recovers to a steady state; and performing lithium plating detection on the battery under test based on the voltage differences during the relaxation periods corresponding to multiple charge-discharge cycles.

[0208] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the displayed or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0209] Furthermore, the units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0210] Furthermore, the functional modules in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0211] In this document, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, without necessarily requiring or implying any such actual relationship or order between these entities or operations.

[0212] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for detecting lithium plating in batteries, characterized in that, include: The voltage difference during the relaxation period after each charge is completed in the charge-discharge cycle of the battery under test is obtained; the relaxation period refers to the time period from the completion of charging to the recovery to steady state of the battery under test; the voltage difference during the relaxation period is the difference between the voltage corresponding to the completion of charging and the voltage at which the battery under test recovers to steady state. Lithium plating detection is performed on the battery under test based on the voltage difference during the relaxation period corresponding to multiple charge-discharge cycles. The lithium plating detection of the battery under test based on the voltage difference during the relaxation period corresponding to multiple charge-discharge cycles includes: A curve showing the change of voltage difference with the number of cycles is generated based on the voltage difference corresponding to multiple charge-discharge cycles. When the change in voltage difference is greater than or equal to a preset threshold, it is determined that the battery under test has lithium plating, and the number of cycles corresponding to the occurrence of lithium plating is recorded. The preset threshold includes a first preset threshold and a second preset threshold, wherein the first preset threshold is less than the second preset threshold; When the change in voltage difference is greater than or equal to the first preset threshold, the amount of lithium plating in the battery under test is determined to be the first degree of lithium plating. When the change in voltage difference is greater than or equal to the second preset threshold, the amount of lithium plating in the battery under test is determined to be the second degree of lithium plating. Wherein, the degree of lithium plating in the first case is less than the degree of lithium plating in the second case; The change in voltage difference is determined to be greater than a preset threshold by at least one of the following: The voltage difference between two adjacent charge-discharge cycles is greater than a preset difference. A voltage difference curve is generated based on the voltage difference corresponding to multiple charge-discharge cycles, and the slope of the voltage difference curve is greater than a preset slope. The differential calculation is performed based on the voltage difference corresponding to multiple charge-discharge cycles, and the obtained differential value is greater than the preset differential value.

2. The method according to claim 1, characterized in that, The acquisition of the voltage difference during the relaxation period after each charge cycle of the battery under test includes: The battery under test is charged until the state of charge of the battery under test reaches a preset state of charge, and the first voltage of the battery under test after charging is recorded. After the battery under test is fully charged, let it rest for a preset time and record the second voltage of the battery under test after resting. The voltage difference during the relaxation period is determined based on the voltage difference between the first voltage and the second voltage.

3. The method according to claim 2, characterized in that, The step of charging the battery under test so that the state of charge of the charged battery reaches a preset state of charge includes: The battery under test is charged with constant current until the voltage of the battery under test after constant current charging reaches the charging cutoff voltage. The battery under test is charged with constant current and then charged with constant voltage to achieve a preset state of charge.

4. The method according to claim 2, characterized in that, The preset duration ranges from [10 minutes to 60 minutes].

5. The method according to claim 1, characterized in that, The method further includes: After determining that the lithium plating level of the battery under test is the first degree of lithium plating, a water drop warning signal is output.

6. The method according to claim 1, characterized in that, The method further includes: Collect the charging and discharging parameters of the battery under test; the charging and discharging parameters include the charging and discharging rate, resting time, and the state of charge (SOC) corresponding to the completion of charging and discharging. The charge and discharge parameters are input into the lithium plating prediction model to obtain the number of charge and discharge cycles at which the battery under test exhibits the first degree of lithium plating, as output by the lithium plating prediction model. The lithium plating prediction model is obtained by training using the following method: The test battery was charged and discharged using various different charging and discharging parameters, and the training voltage difference during the relaxation period after each charge was completed was obtained. The number of charge-discharge cycles corresponding to the first degree of lithium plating in the test battery is determined based on the training voltage difference. The charging and discharging parameters are used as model inputs, and the number of charging and discharging cycles is used as labels for model training to obtain a lithium plating prediction model.

7. The method according to any one of claims 1-6, characterized in that, The method further includes: acquiring battery temperature and internal pressure information of the battery under test during the relaxation period after each charge is completed during the charge-discharge cycle; The lithium plating detection of the battery under test based on the voltage difference during the relaxation period corresponding to multiple charge-discharge cycles includes: The voltage difference is compared with a first voltage threshold to obtain a first comparison result; The battery temperature is compared with a temperature threshold to obtain a second comparison result; The internal pressure information of the battery is compared with a pressure threshold to obtain a third comparison result; Based on the first comparison result, the second comparison result, and the third comparison result, it is determined whether the lithium plating amount of the battery under test has reached the first degree of lithium plating.

8. A lithium plating detection device for batteries, characterized in that, include: The voltage difference acquisition module is used to acquire the voltage difference during the relaxation period after each charge is completed in the charge-discharge cycle of the battery under test; the relaxation period refers to the time period from the completion of charging to the recovery to steady state of the battery under test; the voltage difference during the relaxation period is the difference between the voltage corresponding to the completion of charging and the voltage at which the battery under test recovers to steady state. The detection module is used to detect lithium plating in the battery under test based on the voltage difference during the relaxation period corresponding to multiple charge-discharge cycles. The detection module is specifically used for: A curve showing the change of voltage difference with the number of cycles is generated based on the voltage difference corresponding to multiple charge-discharge cycles. When the change in voltage difference is greater than or equal to a preset threshold, it is determined that the battery under test has lithium plating, and the number of cycles corresponding to the occurrence of lithium plating is recorded. The preset threshold includes a first preset threshold and a second preset threshold, wherein the first preset threshold is less than the second preset threshold; When the change in voltage difference is greater than or equal to the first preset threshold, the amount of lithium plating in the battery under test is determined to be the first degree of lithium plating. When the change in voltage difference is greater than or equal to the second preset threshold, the amount of lithium plating in the battery under test is determined to be the second degree of lithium plating. Wherein, the degree of lithium plating in the first case is less than the degree of lithium plating in the second case; The change in voltage difference is determined to be greater than a preset threshold by at least one of the following: The voltage difference between two adjacent charge-discharge cycles is greater than a preset difference. A voltage difference curve is generated based on the voltage difference corresponding to multiple charge-discharge cycles, and the slope of the voltage difference curve is greater than a preset slope. The differential calculation is performed based on the voltage difference corresponding to multiple charge-discharge cycles, and the obtained differential value is greater than the preset differential value.

9. An electronic device, characterized in that, include: Processor, memory, and bus, among which, The processor and the memory communicate with each other via the bus; The memory stores program instructions that can be executed by the processor, and the processor can execute the method as described in any one of claims 1-7 by calling the program instructions.

10. A non-transitory computer-readable storage medium, characterized in that, The non-transitory computer-readable storage medium stores computer instructions that, when executed by a computer, cause the computer to perform the method as described in any one of claims 1-7.

11. A computer program product, characterized in that, It includes computer program instructions, which, when read and executed by a processor, perform the method as described in any one of claims 1-7.

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