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

Abstract

The invention 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 to-be-tested battery in a relaxation period after each time of charging in a charge-discharge cycle process; the relaxation period refers to a time period from charging completion to steady state recovery of the to-be-tested battery; the voltage difference in the relaxation period is the difference value between the voltage corresponding to the completion of charging of the battery to be tested and the voltage recovered to a steady state; and performing lithium precipitation detection on the to-be-detected battery based on the voltage differences in the relaxation periods corresponding to the multiple charging and discharging cycles. According to the embodiment of the invention, the voltages of the two point positions in the relaxation period after each charging is completed are collected, the voltage difference is calculated through the voltages of the two point positions, lithium precipitation detection is carried out on the to-be-detected battery according to the change condition of the voltage difference in the multiple charging and discharging cycle processes, the collected data amount is small, and the calculated amount is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of battery detection, and in particular to a method, device, electronic device and storage medium for detecting lithium deposition in a battery. Background Art

[0002] Lithium deposition in lithium batteries refers to the deposition and detachment of lithium ions on the electrodes during the charge and discharge process of lithium batteries. During this process, metallic lithium deposits, also known as "lithium dendrites," may form, which can lead to a decrease in battery performance and increase safety risks.

[0003] At present, the voltage relaxation method is mostly used for lithium plating detection of lithium batteries. That is, by charging and discharging the lithium battery, the voltage of the lithium battery during the relaxation process after each charge is completed is recorded to obtain the voltage-time curve, and the voltage-time curve is differentiated to obtain the U' time curve. If there is an inflection point in the U' time curve, it indicates that lithium plating occurs when the battery is charged to the set SOC under specific conditions. This method needs to collect multiple voltage values ​​for a single charge and discharge, and analyze the voltage changes to determine whether lithium plating occurs. Therefore, the amount of calculation is large. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a method, device, electronic device and storage medium for detecting lithium deposition of a battery, so as to reduce the amount of calculation on the basis of realizing lithium deposition detection of the battery.

[0005] In a first aspect, an embodiment of the present application provides a method for detecting lithium deposition of a battery, comprising: Obtain the voltage difference during the relaxation period after each charge is completed during the charge and discharge cycle of the battery to be tested; the relaxation period refers to the time period from the completion of charging to the recovery of the battery to be tested to a steady state; the voltage difference during the relaxation period is the difference between the voltage corresponding to the completion of charging of the battery to be tested and the voltage restored to a steady state; The battery under test is tested for lithium plating based on the voltage difference during the relaxation period corresponding to multiple charge and discharge cycles.

[0006] The embodiment of the present application collects the voltages of two points during the relaxation period after each charging is completed, obtains the voltage difference through the voltage calculation of the two points, and then performs lithium plating detection on the battery to be tested according to the change of the voltage difference during multiple charge and discharge cycles. The amount of data collected is small, thereby reducing the amount of calculation.

[0007] In any embodiment, the lithium deposition detection is performed on the battery to be tested based on the voltage difference during the relaxation period corresponding to multiple charge and discharge cycles, including: Generate a curve of voltage difference versus cycle number based on the voltage difference corresponding to multiple charge and discharge cycles; When the change in the voltage difference is greater than or equal to a preset threshold, it is determined that lithium deposition occurs in the battery to be tested, and the number of cycles corresponding to the occurrence of lithium deposition is recorded.

[0008] In the embodiment of the present application, since the battery is in different lithium deposition stages, it will be reflected in the voltage change curve. Therefore, the degree of lithium deposition and the corresponding number of charge and discharge cycles can be intuitively determined through the voltage change curve.

[0009] In any embodiment, the preset threshold includes a first preset threshold and a second preset threshold, the first preset threshold being less than the second preset threshold; When the change in the voltage difference is greater than or equal to a first preset threshold, determining that the amount of lithium deposition of the battery to be tested is a first lithium deposition degree; When the change in the voltage difference is greater than or equal to a second preset threshold, determining that the amount of lithium deposition of the battery to be tested is a second lithium deposition degree; Among them, the first lithium precipitation degree is less than the second lithium precipitation degree.

[0010] In the embodiment of the present application, since a large amount of lithium deposition occurs in the battery, the corresponding lithium stripping and lithium reinsertion reactions reach equilibrium, and the voltage difference is a mixed voltage of the two reactions, the voltage difference will increase significantly, and the degree of lithium deposition will continue to increase with the increase of the voltage difference. Therefore, by judging whether the change in the voltage difference is greater than the preset threshold, the accuracy of detecting whether a large amount of lithium deposition occurs can be improved.

[0011] In any embodiment, the change in the voltage difference is determined to be greater than a preset threshold by at least one of the following: The difference between the voltage differences corresponding to two adjacent charge and discharge cycles is greater than a preset difference; Generating a voltage difference curve based on the voltage differences corresponding to the multiple charge and discharge cycles, wherein the slope of the voltage difference curve is greater than a preset slope; A differential calculation is performed based on the voltage differences corresponding to the multiple charge and discharge cycles, and the obtained differential value is greater than the preset differential value.

[0012] The embodiment of the present application can improve the accuracy of detecting whether a large amount of lithium deposition occurs by judging whether the change in the voltage difference is greater than a preset threshold.

[0013] In any embodiment, obtaining the voltage difference during the relaxation period after each charge is completed during the charge and discharge cycle of the battery to be tested includes: Charging the battery to be tested so that the state of charge of the battery to be tested after charging reaches a preset state of charge, and recording a first voltage of the battery to be tested after charging is completed; The charged battery to be tested is left to stand for a preset time, and a second voltage of the battery to be tested is recorded after the battery is left to stand; The voltage difference during relaxation is determined based on the voltage difference between the first voltage and the second voltage.

[0014] In the embodiment of the present application, the voltage difference between the two points after each charging is completed is calculated, and the lithium plating detection of the battery to be tested is performed through the change of the voltage difference corresponding to multiple charge and discharge cycles. Therefore, the amount of data collected is small, thereby reducing the amount of calculation.

[0015] In any embodiment, charging the battery to be tested so that the state of charge of the battery to be tested reaches a preset state of charge includes: Performing constant current charging on the battery to be tested, so that the voltage of the battery to be tested after constant current charging reaches the charging cut-off voltage; The battery to be tested after constant current charging is charged at a constant voltage, so that the charge state of the battery to be tested after constant voltage charging reaches a preset charge state.

[0016] The embodiment of the present application reduces the influence of internal polarization of the battery by first charging at a constant current to a cut-off voltage and then charging at a constant voltage, so that the actual charge state of the battery to be tested reaches a preset charge state, thereby improving the accuracy of lithium plating detection of the battery to be tested.

[0017] In any embodiment, the preset duration ranges from [10 minutes to 60 minutes].

[0018] In the embodiment of the present application, if the resting time is too short, the battery to be tested will not reach a steady state, affecting the accuracy of lithium deposition detection; if the resting time is too long, the battery to be tested will be stored at a high SOC, resulting in performance deterioration. Therefore, the present application presets a reasonable resting time, on the one hand, to improve the accuracy of lithium deposition detection, on the other hand, to reduce the damage to the battery to be tested.

[0019] In any embodiment, the method further comprises: After determining that the lithium deposition amount of the battery to be tested is the first lithium deposition level, a water diving warning signal is output.

[0020] The embodiment of the present application outputs a diving warning signal after determining that the lithium deposition amount of the battery to be tested has reached a first lithium deposition level. Since the lithium deposition amount reaches the first lithium deposition level, it indicates that the battery is in a state of large-scale lithium deposition. If the battery continues to be used, it may cause danger. Therefore, by outputting the diving warning signal, a warning effect is played, and the timing of the warning is relatively reasonable.

[0021] In any embodiment, the method further comprises: Collect the charge and discharge parameters of the battery to be tested; the charge and discharge parameters include the charge and discharge rate, the rest time and the SOC corresponding to the completion of charge and discharge respectively; Inputting the charge and discharge parameters into the lithium deposition prediction model, and obtaining the number of charge and discharge cycles at which the first lithium deposition level of the battery to be tested occurs, output by the lithium deposition prediction model; Among them, the lithium precipitation prediction model is obtained by training through the following method: The test battery is charged and discharged using a variety of different charge and discharge parameters, and the training voltage difference during the relaxation period after each charge is completed is obtained; Determine the number of charge and discharge cycles corresponding to the lithium deposition amount of the test battery reaching a first lithium deposition level based on the training voltage difference; The charge and discharge parameters are used as model input, and the number of charge and discharge cycles is used as a label for model training to obtain a lithium precipitation prediction model.

[0022] The embodiment of the present application analyzes the charge and discharge parameters through a lithium precipitation prediction model, introduces an artificial intelligence model, and improves the accuracy and efficiency of lithium precipitation prediction.

[0023] In any embodiment, the method further comprises: Obtain the battery temperature and internal pressure information of the battery during the relaxation period after each charge is completed during the charge and discharge cycle of the battery under test; Based on the voltage difference during the relaxation period corresponding to multiple charge and discharge cycles, the battery under test is tested for lithium deposition, including: Comparing the voltage difference with a first voltage threshold to obtain a first comparison result; Comparing the battery temperature with a temperature threshold to obtain a second comparison result; Comparing the internal pressure information of the battery with the pressure threshold to obtain a third comparison result; It is determined whether the amount of lithium deposition of the battery to be tested reaches a first lithium deposition level according to the first comparison result, the second comparison result and the third comparison result.

[0024] The embodiment of the present application determines whether the amount of lithium deposition of the battery to be tested reaches the first lithium deposition level by combining the voltage difference, the battery temperature and the internal pressure of the battery, thereby improving the accuracy of lithium deposition level detection.

[0025] In a second aspect, an embodiment of the present application provides a battery lithium deposition detection device, comprising: The voltage difference acquisition module is used to obtain the voltage difference during the relaxation period after each charging is completed during the charge and discharge cycle of the battery to be tested; the relaxation period refers to the time period from the completion of charging to the recovery of the battery to be tested to a steady state; the voltage difference during the relaxation period is the difference between the voltage corresponding to the completion of charging of the battery to be tested and the voltage restored to a steady state; The detection module is used to perform lithium deposition detection on the battery to be tested based on the voltage difference during the relaxation period corresponding to multiple charge and discharge cycles.

[0026] In a third aspect, an embodiment of the present application provides an electronic device, including: a processor, a memory, and a bus, wherein: The processor and memory communicate with each other through the bus; The memory stores program instructions that can be executed by the processor, and the processor calls the program instructions to execute the method of the first aspect.

[0027] In a fourth aspect, an embodiment of the present application provides a non-transitory computer-readable storage medium, including: The non-transitory computer-readable storage medium stores computer instructions, which cause a computer to execute the method of the first aspect.

[0028] In a fifth aspect, an embodiment of the present application provides a computer program product, comprising computer program instructions, which, when read and executed by a processor, execute the method of the first aspect.

[0029] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by practicing the embodiments of the present application. The purpose and other advantages of the present application can be realized and obtained by the structures specifically pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 A schematic diagram of a battery lithium plating detection method provided in an embodiment of the present application; Figure 2 A capacity retention rate curve diagram provided in an embodiment of the present application; Figure 3 A voltage difference curve diagram provided in an embodiment of the present application; Figure 4 A schematic diagram of the structure of a battery lithium deposition detection device provided in an embodiment of the present application; Figure 5 A schematic diagram of the physical structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0032] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0034] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0035] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0036] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0037] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0038] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0039] As a green energy source, lithium-ion batteries have the advantages of high voltage, high energy density and no memory effect. They have developed rapidly in recent years and have been widely used in many fields.

[0040] Lithium plating is an abnormal phenomenon that is prone to occur during the charging process of lithium-ion batteries, especially in the case of fast charging or low-temperature charging. When the battery potential of graphite is lower than the electrode potential of lithium, lithium ions gather on the graphite surface and have no time to embed, resulting in lithium plating. Lithium plating will not only accelerate capacity decay and shorten service life, but the precipitated lithium may also pierce the battery separator, causing a short circuit in the battery and causing safety problems. The above situations will accelerate the aging of lithium-ion batteries, resulting in reduced battery performance and even more serious consequences. Therefore, in order to ensure the normal use of the battery and reduce risks, it is necessary to detect the lithium plating phenomenon of the battery in a timely manner and issue an early warning for potential aging.

[0041] In the current related technology, the voltage relaxation method is used to detect lithium deposition in batteries. This method requires collecting more voltage data during the relaxation process after each charge and discharge, and then differentiating the collected voltage data to determine whether lithium deposition has occurred. This method requires collecting a lot of data for each cycle, which increases the amount of calculation.

[0042] In order to solve the above technical problems, the embodiments of the present application provide a method, device, electronic device and storage medium for detecting lithium deposition of a battery. The lithium deposition detection method detects the lithium deposition of the battery to be tested based on the voltage difference corresponding to multiple charge and discharge cycles by acquiring the voltage difference during the relaxation period after each charging is completed. Therefore, the present application can collect the voltage of two points during the relaxation period, which greatly reduces the number and amount of calculation of voltage data collection.

[0043] It should be noted that the embodiments of the present application can perform lithium plating detection on lithium-ion cells or batteries containing lithium-ion cells. For ease of description, the embodiments of the present application collectively refer to cells and batteries containing cells as batteries to be tested.

[0044] It can be understood that the battery lithium plating detection method provided in the embodiment of the present application can be applied to electronic devices, which include a terminal and a server; wherein the terminal can specifically be a smart phone, a tablet computer, a computer, a personal digital assistant (PDA), etc.; the server can specifically be an application server or a Web server.

[0045] Figure 1 A schematic flow chart of a method for detecting lithium deposition in a battery provided in an embodiment of the present application is shown in FIG. Figure 1 As shown, the method includes: Step 101: obtaining a voltage difference during a relaxation period after each charge is completed during the charge and discharge cycle of the battery to be tested; the relaxation period refers to the time period from when the battery to be tested is charged to when it is restored to a steady state; the voltage difference during the relaxation period is the difference between the voltage corresponding to when the battery to be tested is charged and the voltage when it is restored to a steady state; Step 102: Perform lithium deposition detection on the battery to be tested based on the voltage difference during relaxation periods corresponding to multiple charge and discharge cycles.

[0046] In the specific implementation process, the battery to be tested can be a battery that has just left the factory and has not been used, a battery that has been used for a period of time, or a retired battery. In the process of lithium plating detection of the battery to be tested, a charging and discharging device can be used to perform a charge and discharge cycle on the battery to be tested. The charging and discharging device can be an electrochemical workstation, etc.

[0047] Since the lithium plating phenomenon generally occurs during the charging process of the battery, after the battery to be tested is charged once, a voltage acquisition device can be used to collect the voltage difference during the relaxation period after the battery is charged. It should be noted that after the battery to be tested is charged, there is polarization inside it, which is referred to as the polar state in the embodiment of the present application. By standing still, the internal polarization of the battery to be tested can be reduced so that the battery to be tested reaches a steady state or an approximate steady state. Therefore, the time corresponding to the battery to be tested from the polar state to the steady state or the approximate steady state is called the relaxation period. Therefore, the voltage difference during the relaxation period can be the difference between the voltage of the battery to be tested after charging is completed and the voltage restored to the steady state.

[0048] During the charge and discharge cycle of the battery to be tested, the voltage difference can be obtained by the above method after each charge is completed, or the voltage difference can be obtained discontinuously, that is, the voltage difference can be obtained once after multiple charge and discharge cycles. Therefore, multiple voltage differences can be obtained, and then the battery to be tested is tested for lithium deposition based on the changes in the multiple voltage differences. The lithium deposition degree of the battery to be tested and the corresponding number of charge and discharge cycles can be determined through lithium deposition detection.

[0049] The embodiment of the present application collects the voltages of two points during the relaxation period after each charging is completed, obtains the voltage difference through the voltage calculation of the two points, and then performs lithium plating detection on the battery to be tested according to the change of the voltage difference during multiple charge and discharge cycles. The amount of data collected is small, thereby reducing the amount of calculation.

[0050] On the basis of the above embodiment, the lithium deposition detection is performed on the battery to be tested based on the voltage difference during the relaxation period corresponding to multiple charge and discharge cycles, including: Generate a curve of voltage difference versus cycle number based on the voltage difference corresponding to multiple charge and discharge cycles; When the change in the voltage difference is greater than or equal to a preset threshold, it is determined that lithium deposition occurs in the battery to be tested, and the number of cycles corresponding to the occurrence of lithium deposition is recorded.

[0051] In the specific implementation process, during the relaxation period after the battery to be tested is charged, the battery to be tested recovers from the extreme state to the steady state. During the relaxation period, the lithium ions in the battery to be tested are embedded in the graphite layers to form LixC6 or lithium is precipitated 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 part of the lithium to discharge into lithium ions, and the lithium ions are back-intercalated into the graphite. Therefore, the lithium deposition phenomenon of the battery to be tested can be analyzed in three stages with multiple charge and discharge cycles: 1. No lithium deposition or a small amount of lithium deposition: If the amount of lithium deposition is small, the lithium stripping current is lower than the lithium re-embedding current in graphite, and lithium ions are mainly embedded in the graphite interlayer. 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 deposition, a large amount of lithium deposition: Because the lithium stripping and lithium re-embedding reactions reach equilibrium, the relaxation voltage is expressed as a mixed voltage of the two reactions, indicating that lithium deposition and LixC6 coexist. At this time, the voltage change during relaxation increases, that is, the voltage difference suddenly increases; 3. Severe lithium deposition: The relaxation voltage is dominated by the open circuit voltage of lithium metal, and the voltage difference during relaxation reaches the maximum value. Therefore, in different lithium deposition stages, the voltage difference of the battery to be tested during relaxation is expressed in different forms.

[0052] In order to verify the above analysis, the present application embodiment is tested with a comparative example and an embodiment, wherein: Comparative example: After charging to the charge cut-off voltage under constant current (CC) charging with a current of 1C, constant voltage charging is performed to 100% SOC, and the actual voltage ① is recorded. After standing for 10 minutes, the actual voltage ② is recorded. After discharging to the discharge cut-off voltage under a current of 1C (constant current discharge), the battery is allowed to stand for relaxation for 10 minutes. This process is the charge and discharge process for each cycle.

[0053] Example: Except that the charge and discharge rate is 2C, other conditions are the same as those of the comparative example.

[0054] The comparative example and the embodiment are charged and discharged in the above manner, and the capacity retention rate corresponding to each charge and discharge cycle is recorded. A capacity retention rate change curve is generated according to the capacity retention rate and the corresponding number of cycles, such as Figure 2 As shown, since the charge and discharge rate of the embodiment is greater than that of the comparative example, the capacity retention rate of the embodiment suddenly decreases after about 600 cycles, which indicates that the capacity of the battery corresponding to the embodiment has dropped.

[0055] During the charge and discharge cycle of the comparative example and the embodiment, the voltage difference during the relaxation period after each charge and discharge is completed can be recorded respectively, and the recorded voltage difference and the corresponding cycle number are used to generate a voltage change curve, such as Figure 3 As shown in FIG. 1 , the lithium deposition condition of the battery to be tested can be determined based on the voltage variation curve. Figure 3 It can be seen that the voltage difference of the batteries under test corresponding to the comparative example and the embodiment respectively increases suddenly around the 600th charge and discharge cycle. Therefore, it can be determined that a large amount of lithium deposition occurs in the two batteries under test around the 600th charge and discharge cycle. Figure 3 and Figure 2 The experimental results are corresponding.

[0056] In addition, the degree of lithium deposition may include not only a large amount of lithium deposition, but also severe lithium deposition. Severe lithium deposition may be determined by the voltage difference reaching a maximum value.

[0057] In the embodiment of the present application, since the battery is in different lithium deposition stages, it will be reflected in the voltage change curve. Therefore, the degree of lithium deposition and the corresponding number of charge and discharge cycles can be intuitively determined through the voltage change curve.

[0058] There are many non-destructive testing methods that can determine the starting point of lithium deposition in the battery to be tested, but the impact of a small amount of lithium deposition on battery performance cannot be directly determined and may have a small impact. If the performance deterioration is warned by the starting point of lithium deposition, there may be a problem of excessive warning. In the actual use of the battery, when lithium deposition continues to accumulate to form lithium dendrites and then puncture the isolation membrane, it may lead to a safety accident. Before this, it is more valuable to warn the battery.

[0059] Therefore, when the embodiment of the present application performs lithium deposition detection on the battery, its preset threshold value may include a first preset threshold value and a second preset threshold value, wherein the first preset threshold value is less than the second preset threshold value; when the change in the voltage difference is greater than or equal to the first preset threshold value, the lithium deposition amount of the battery to be tested is determined to be a first lithium deposition degree; when the change in the voltage difference is greater than or equal to the second preset threshold value, the lithium deposition amount of the battery to be tested is determined to be a second lithium deposition degree; wherein the first lithium deposition degree is less than the second lithium deposition degree.

[0060] In a specific implementation process, when judging the degree of lithium deposition, the voltage difference can be compared with a preset threshold value. If the voltage difference is greater than or equal to the first preset threshold value, it is determined that the amount of lithium deposition of the battery to be tested has reached the first lithium deposition degree. The first lithium deposition degree is used to characterize a large amount of lithium deposition, that is, the amount of lithium deposition of the battery to be tested has accumulated into lithium dendrites. If it continues to be used, there is a risk of piercing the isolation membrane. Therefore, in actual applications, if it is detected that the degree of lithium deposition of the battery to be tested reaches the first lithium deposition degree, an alarm prompt can be issued.

[0061] If the voltage difference is greater than or equal to the second preset threshold, it is determined that the amount of lithium deposition of the battery to be tested has reached the second lithium deposition level. The second lithium deposition level is used to characterize severe lithium deposition, which is greater than the amount of lithium deposition of the first lithium deposition level, that is, the amount of lithium deposition of the battery to be tested has reached the limit value of piercing the isolation membrane, and the isolation membrane is about to be pierced.

[0062] The embodiments of the present application can determine the points where a large amount of lithium deposition and severe lithium deposition occur in the battery to be tested. Therefore, in order to improve the safety of the battery, the detection of the degree of lithium deposition of the battery to be tested provides a basis for more timely alarm.

[0063] 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 judged whether the change in the voltage difference is greater than the preset threshold. If it is greater than the preset threshold, it means that the voltage difference suddenly increases, and then it can be determined that the battery to be tested has a lithium plating phenomenon of the first degree.

[0064] When the voltage difference reaches the maximum value, it means that the relaxation voltage is dominated by the open circuit voltage of lithium metal. At this time, the battery under test is seriously lithium-deposited, that is, the second degree of lithium-deposit phenomenon.

[0065] In the embodiment of the present application, since a large amount of lithium deposition occurs in the battery, the corresponding lithium stripping and lithium re-insertion reactions reach equilibrium, and the voltage difference manifests itself as a mixed voltage of the two reactions. Therefore, the voltage difference will increase significantly. Therefore, by judging whether the change in the voltage difference is greater than a preset threshold, the accuracy of detecting whether a large amount of lithium deposition occurs can be improved.

[0066] Based on the above embodiment, it can be determined that the change in the voltage difference is greater than the preset threshold by at least one of the following: 1. The difference between the voltage differences corresponding to two adjacent charge and discharge times is greater than the preset difference; 2. generating a voltage difference curve based on the voltage differences corresponding to the multiple charge and discharge cycles, wherein the slope of the voltage difference curve is greater than a preset slope; 3. Perform differential calculation based on the voltage differences corresponding to multiple charge and discharge cycles, and the obtained differential value is greater than the preset differential value.

[0067] In a specific implementation process, each charge and discharge cycle corresponds to a voltage difference, and the voltage difference corresponding to each charge and discharge cycle and the corresponding number of cycles can be used to generate a voltage change curve, such as Figure 3 As shown, based on the voltage change curve, the voltage difference corresponding to the current charge and discharge can be compared with the voltage difference corresponding to the previous charge and discharge to obtain the difference. If the difference is greater than the preset difference, it indicates that the voltage difference suddenly increases, and it is determined that a large amount of lithium deposition occurs in the battery to be tested. It should be noted that the minimum number of cycles corresponding to the sudden increase in the voltage difference is the starting point for a large amount of lithium deposition in the battery to be tested. Thereafter, as the battery to be tested continues to be charged and discharged, the amount of lithium deposition gradually increases. In addition, when the electronic device obtains the voltage difference during the relaxation period after the charging is completed, it can be obtained at intervals, and the number of intervals can be 1, 2, 5, 10... The smaller the number of intervals, the more accurate the lithium deposition detection of the battery to be tested, and accordingly, the amount of calculation is also large; the larger the number of intervals, the smaller the amount of calculation, and the accuracy of the lithium deposition detection of the battery to be tested will be reduced accordingly. The specific value of the number of intervals is not infinite, and an upper limit value can be given based on the actual situation, such as a maximum value of 50 or 100. Taking the interval number of 10 as an example, the electronic device can obtain the voltage difference corresponding to the 10th, 20th, 30th, ... charge and discharge cycles, where the difference between the voltage difference corresponding to the 10th charge and discharge cycle and the voltage difference corresponding to the 20th charge and discharge cycle is called the difference between the voltage differences corresponding to two adjacent charge and discharge cycles. The difference between the voltage difference corresponding to the 20th charge and discharge cycle and the voltage difference corresponding to the 30th charge and discharge cycle is called the difference between the voltage differences corresponding to two adjacent charge and discharge cycles.

[0068] After obtaining the voltage differences corresponding to multiple charge and discharge cycles, the electronic device generates a voltage difference curve based on the 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 the preset slope is the starting point for a large amount of lithium deposition in the battery to be tested. Thereafter, as the battery to be tested continues to be charged and discharged, the amount of lithium deposition gradually increases.

[0069] It is also possible to perform differential calculations based on the voltage differences corresponding to the charge and discharge cycles, obtain differential values ​​corresponding to the respective number of cycles, and use the minimum number of cycles with a differential value greater than a preset differential value as the starting point for a large amount of lithium deposition in the battery to be tested. Subsequently, as the battery to be tested continues to be charged and discharged, the amount of lithium deposition gradually increases.

[0070] The embodiment of the present application can improve the accuracy of detecting whether a large amount of lithium deposition occurs by judging whether the change in the voltage difference is greater than a preset threshold.

[0071] On the basis of the above embodiment, obtaining the voltage difference during the relaxation period after each charging is completed during the charge and discharge cycle of the battery to be tested includes: Charging the battery to be tested so that the state of charge of the battery to be tested after charging reaches a preset state of charge, and recording a first voltage of the battery to be tested after charging is completed; The charged battery to be tested is left to stand for a preset time, and a second voltage of the battery to be tested is recorded after the battery is left to stand; The voltage difference of the battery under test during the relaxation period is determined according to the voltage difference between the first voltage and the second voltage.

[0072] In a specific implementation process, a charging and discharging device is used to charge the battery to be tested so that the state of charge of the battery to be tested reaches a preset state of charge, wherein the value range of the preset state of charge can be (0, 100%], preferably, its value range can be [50%, 100%]. In the embodiment of the present application, the preset state of charge is 100% as an example. When the battery to be tested is charged to 100% SOC, charging is stopped, and the first voltage of the battery to be tested at the current time is recorded. Then, the battery to be tested is allowed to stand for a preset time, and after the preset time is stood, the second voltage of the battery to be tested is recorded. The value range of the preset time can be [10 minutes, 60 minutes], preferably, the value range of the preset time can be [10 minutes, 30 minutes] . In the embodiment of the present application, the period when the battery to be tested is at rest is called the relaxation period. During this period, the battery recovers from the extreme state to a steady state or an approximate steady state. It should be noted that the preset time length should not be selected to be too small or too large. If the preset time length is too small, the battery to be tested cannot reach a steady state or an approximate steady state, which will cause the second voltage detection to be inaccurate and affect the subsequent lithium plating detection. If the preset time length is too large, the battery to be tested will be stored at a high SOC for a long time, causing the battery performance to deteriorate. In addition, after the battery to be tested is charged, the time required to reach a steady state is affected by factors such as the charging rate, temperature, and degree of battery aging. For example, the greater the charging rate, the longer it takes for the battery to be tested to recover to a steady state. Therefore, when determining the preset time length, it can be determined based on factors such as the charging rate, temperature, and degree of battery aging of the battery to be tested.

[0073] 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 to be tested during the relaxation period.

[0074] The embodiment of the present application calculates the voltage difference between two points after each charging is completed, and performs lithium plating detection on the battery to be tested through the change of the voltage difference corresponding to multiple charge and discharge cycles. Therefore, the amount of data collected is small, thereby reducing the amount of calculation.

[0075] On the basis of the above embodiment, charging the battery to be tested so that the state of charge of the battery to be tested reaches a preset state of charge includes: Performing constant current charging on the battery to be tested, so that the voltage of the battery to be tested after constant current charging reaches the cut-off voltage; The battery to be tested after constant current charging is charged at a constant voltage, so that the charge state of the battery to be tested after constant voltage charging reaches a preset charge state.

[0076] In the specific implementation process, when charging the battery to be tested, it can be first charged with a constant current. For example, the battery to be tested can be charged with a constant current with a charging rate of 1C, so that the voltage of the battery to be tested reaches the cut-off voltage. It can be understood that the cut-off voltage refers to the voltage corresponding to the preset state of charge that the battery to be tested is to reach. After the battery to be tested reaches the cut-off voltage after constant current charging, due to the internal polarization of the battery, its actual voltage is less than the cut-off voltage, indicating that the actual state of charge of the battery to be tested after charging has not reached the preset state of charge. Therefore, the battery after constant current charging can be charged with a constant voltage so that the state of charge of the battery to be tested after charging reaches the preset state of charge.

[0077] In addition, the battery to be tested can be charged with a small constant current so that the state of charge of the battery to be tested reaches a preset state of charge. Due to the small current charging, the polarization reaction inside the battery to be tested is small and can be ignored. When charging the battery to be tested, constant voltage charging can also be used so that the state of charge of the battery to be tested reaches a preset state of charge.

[0078] The embodiment of the present application reduces the influence of internal polarization of the battery by first charging at a constant current to a cut-off voltage and then charging at a constant voltage, so that the actual charge state of the battery to be tested reaches a preset charge state, thereby improving the accuracy of lithium plating detection of the battery to be tested.

[0079] Based on the above embodiment, the method further includes: Collect the charge and discharge parameters of the battery to be tested; the charge and discharge parameters include the charge and discharge rate, the rest time and the SOC corresponding to the completion of charge and discharge respectively; The charge and discharge parameters are input into the lithium deposition prediction model to obtain the number of charge and discharge cycles at which the first lithium deposition level of the battery to be tested occurs, which is output by the lithium deposition prediction model.

[0080] In the specific implementation process, the lithium precipitation prediction model is obtained by pre-training, and the training method is as follows: A plurality of different charge and discharge parameters are used to charge and discharge the test battery, and the training voltage difference during the relaxation period after each charge is completed is obtained; wherein the charge and discharge parameters may include the charge rate, the discharge rate, the rest time after each charge is completed, and the SOC corresponding to each charge completion. It should be noted that the training voltage difference is similar to the voltage difference in the above embodiment, but the corresponding battery is different, which will not be repeated here.

[0081] The number of charge and discharge cycles corresponding to the amount of lithium deposition of the test battery reaching the first lithium deposition level is determined based on the training voltage difference; it should be noted that the method for determining whether the amount of lithium deposition has reached the first lithium deposition level based on the training voltage difference can be referred to in the above embodiment, and the method for judging whether the amount of lithium deposition has reached the first lithium deposition level based on the voltage difference will not be repeated here.

[0082] The charge and discharge parameters are used as model input, and the number of charge and discharge cycles is used as a label for model training to obtain a lithium precipitation prediction model.

[0083] After obtaining the lithium deposition prediction model, for the battery to be tested, the charge and discharge parameters of the battery to be tested can be collected, and then the charge and discharge parameters can be input into the trained lithium deposition prediction model to obtain the number of charge and discharge cycles for the battery to be tested to produce the first degree of lithium deposition, as output by the lithium deposition prediction model.

[0084] The embodiment of the present application analyzes the charge and discharge parameters through a lithium precipitation prediction model, introduces an artificial intelligence model, and improves the accuracy and efficiency of lithium precipitation prediction.

[0085] Based on the above embodiment, the method further includes: Obtain the battery temperature and internal pressure information of the battery during the relaxation period after each charge is completed during the charge and discharge cycle of the battery under test; Based on the voltage difference during the relaxation period corresponding to multiple charge and discharge cycles, the battery under test is tested for lithium deposition, including: Comparing the voltage difference with a first voltage threshold to obtain a first comparison result; Comparing the battery temperature with a temperature threshold to obtain a second comparison result; Comparing the internal pressure information of the battery with the pressure threshold to obtain a third comparison result; It is determined whether the amount of lithium deposition of the battery to be tested reaches a first lithium deposition level according to the first comparison result, the second comparison result and the third comparison result.

[0086] In the specific implementation process, in addition to judging the lithium deposition of the battery based on the voltage difference during the relaxation period after each charge is completed, the battery temperature and the internal pressure information of the battery can also be used to characterize the lithium deposition of the battery. Specifically: the battery temperature and the internal pressure information of the battery during the relaxation period after each charge is completed during the charge and discharge cycle of the battery to be tested can be obtained. It can be understood that the battery temperature can be the average temperature of the battery during the relaxation period, the maximum temperature, or the middle value of the temperature. The internal pressure information of the battery can be the average pressure of the battery during the relaxation period, the maximum pressure or the middle value of the pressure.

[0087] The corresponding thresholds are used for comparison of the voltage difference, battery temperature and internal battery pressure, that is, the voltage difference is compared with the first voltage threshold to obtain a first comparison result; if the voltage difference is greater than the first voltage threshold, it can be preliminarily considered that the battery to be tested has undergone a first lithium deposition amount. The battery temperature is compared with the temperature threshold to obtain a second comparison result; if the battery temperature is greater than the temperature threshold, it can be preliminarily considered that the battery to be tested has undergone a first lithium deposition amount. The internal battery pressure information is compared with the pressure threshold to obtain a third comparison result. If the internal battery pressure information is greater than the pressure threshold, it can be preliminarily considered that the battery to be tested has undergone a first lithium deposition amount. Among them, the first voltage threshold, the temperature threshold and the pressure threshold can all be set according to actual conditions.

[0088] After obtaining the first comparison result, the second comparison result, and the third comparison result, if two or more comparison results indicate that the battery to be tested has a first lithium deposition level of lithium deposition, it can be finally determined that the battery to be tested has a first lithium deposition level of lithium deposition. Otherwise, it means that the battery to be tested has not reached the first lithium deposition level of lithium deposition. Alternatively, a weighted average can be performed based on the first comparison result, the second comparison result, and the third comparison result to obtain a score for the amount of lithium deposition of the battery to be tested that reaches the first lithium deposition level. If the score is higher than the preset score, it is determined that the battery to be tested has reached the first lithium deposition level of lithium deposition. Among them, the weights corresponding to each comparison result can be set according to actual conditions.

[0089] The embodiment of the present application determines whether the amount of lithium deposition of the battery to be tested reaches the first lithium deposition level by combining the voltage difference, the battery temperature and the internal pressure of the battery, thereby improving the accuracy of lithium deposition level detection.

[0090] The present application embodiment provides a comparative example and six embodiments of the lithium plating detection process, wherein: Comparative example: After charging to the charge cut-off voltage under constant current (CC) charging with a current of 1C, constant voltage charging is performed to 100% SOC, and the actual voltage ① is recorded. After standing for 10 minutes, the actual voltage ② is recorded. After discharging to the discharge cut-off voltage under a current of 1C (constant current discharge), the battery is allowed to stand for relaxation for 10 minutes. This process is the charge and discharge process for each cycle.

[0091] Example 1: Except that the charge and discharge rate is 2C, other conditions are the same as those of the comparative example.

[0092] Example 2: Except that the charge and discharge rate is 0.5C, other conditions are the same as those of the comparative example.

[0093] Example 3: Except that the standing time is 60 min, other conditions are the same as those of the comparative example.

[0094] Example 4: Except that the standing time is 120 min, other conditions are the same as those of the comparative example.

[0095] Example 5: Except for charging to 80% SOC, other conditions are the same as in Example 5.

[0096] Example 6: Except for charging to 50% SOC, other conditions are the same as in Example 6.

[0097] After charging and discharging the comparative example and the embodiment in the above manner, the following results can be obtained:

[0098] From the above table we can conclude that: By comparing Example 1 and Example 2 with the comparative example, the greater the charging rate, the faster the battery ages (see the cycle corresponding to the cycle to 85% SOH). In Example 1, a large amount of lithium deposition occurs around 600 cycles, and the battery dive occurs at this time, indicating that the voltage change suddenly increases during the charging process. The cycle can realize the dive warning.

[0099] By comparing Example 3 and Example 4 with the comparative example, the effect of the standing time on the charge-discharge cycle is explained, that is, too long a standing time will lead to a decrease in battery performance.

[0100] By comparing Example 5 and Example 6 with the comparative example, it is shown that when charging to different SOCs, the voltage change during the charging process can still be used to achieve a diving warning. Therefore, the embodiment of the present application is suitable for lithium plating detection of batteries charged to (0, 100% SOC]. In addition to charging the battery to be tested to 50% SOC and 100% SOC, the embodiment of the present application also tests the battery to be tested by charging it to 10% SOC, 30% SOC, and 75% SOC, respectively, which can achieve the purpose of lithium plating detection of the battery to be tested.

[0101] Figure 4 This is a schematic diagram of the structure of a battery lithium deposition detection device provided in an embodiment of the present application. The device can be a module, program segment or code on an electronic device. It should be understood that the device is similar to the above-mentioned Figure 1 The method embodiment corresponds to 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 above description. To avoid repetition, detailed description is appropriately omitted here. The device includes: a voltage difference acquisition module 401 and a detection module 402, wherein: The voltage difference acquisition module 401 is used to obtain the voltage difference during the relaxation period after each charging is completed during the charge and discharge cycle of the battery to be tested; the relaxation period refers to the time period corresponding to the completion of charging of the battery to be tested to the recovery to the steady state; the voltage difference during the relaxation period is the difference between the voltage corresponding to the completion of charging of the battery to be tested and the voltage restored to the steady state; The detection module 402 is used to perform lithium deposition detection on the battery to be tested based on the voltage difference during the relaxation periods corresponding to multiple charge and discharge cycles.

[0102] Based on the above embodiment, the detection module 402 is specifically used for: Generate a curve of voltage difference versus cycle number based on the voltage difference corresponding to multiple charge and discharge cycles; When the change in the voltage difference is greater than or equal to a preset threshold, it is determined that lithium deposition occurs in the battery to be tested, and the number of cycles corresponding to the occurrence of lithium deposition is recorded.

[0103] On the basis of the above embodiment, the preset threshold includes a first preset threshold and a second preset threshold, and the first preset threshold is less than the second preset threshold; the detection module 402 is specifically used for: When the change in the voltage difference is greater than or equal to a first preset threshold, determining that the amount of lithium deposition of the battery to be tested is a first lithium deposition degree; When the change in the voltage difference is greater than or equal to a second preset threshold, determining that the amount of lithium deposition of the battery to be tested is a second lithium deposition degree; Among them, the first lithium precipitation degree is less than the second lithium precipitation degree.

[0104] Based on the above embodiment, it is determined that the change in the voltage difference is greater than the preset threshold value by at least one of the following: The difference between the voltage differences corresponding to two adjacent charge and discharge cycles is greater than a preset difference; Generating a voltage difference curve based on voltage differences corresponding to a plurality of charge and discharge cycles, wherein a slope of the voltage difference curve is greater than a preset slope; A differential calculation is performed based on the voltage differences corresponding to the multiple charge and discharge cycles, and the obtained differential value is greater than the preset differential value.

[0105] Based on the above embodiment, the voltage difference acquisition module 401 is specifically used for: Charging the battery to be tested so that the state of charge of the battery to be tested after charging reaches a preset state of charge, and recording a first voltage of the battery to be tested after charging is completed; The charged battery to be tested is left to stand for a preset time, and a second voltage of the battery to be tested is recorded after the battery is left to stand; The voltage difference during relaxation is determined based on the voltage difference between the first voltage and the second voltage.

[0106] Based on the above embodiment, the voltage difference acquisition module 401 is specifically used for: Performing constant current charging on the battery to be tested, so that the voltage of the battery to be tested after constant current charging reaches the charging cut-off voltage; The battery to be tested after constant current charging is charged at a constant voltage, so that the charge state of the battery to be tested after constant voltage charging reaches a preset charge state.

[0107] Based on the above embodiment, the value range of the preset duration is [10 minutes, 60 minutes].

[0108] Based on the above embodiment, the device further includes an early warning module, which is used to: After determining that the lithium deposition amount of the battery to be tested is the first lithium deposition level, a water diving warning signal is output.

[0109] Based on the above embodiment, the device further includes a model analysis module, which is used to: Collecting the charge and discharge parameters of the battery to be tested; the charge and discharge parameters include the charge and discharge rate, the rest time and the SOC corresponding to the completion of charge and discharge respectively; Inputting the charge and discharge parameters into the lithium deposition prediction model, and obtaining the number of charge and discharge cycles at which the first lithium deposition level of the battery to be tested occurs, output by the lithium deposition prediction model; Among them, the lithium precipitation prediction model is obtained by training through the following method: The test battery is charged and discharged using a variety of different charge and discharge parameters, and the training voltage difference during the relaxation period after each charge is completed is obtained; Determine the number of charge and discharge cycles corresponding to the lithium deposition amount of the test battery reaching a first lithium deposition level based on the training voltage difference; The charge and discharge parameters are used as model input, and the number of charge and discharge cycles is used as a label for model training to obtain a lithium precipitation prediction model.

[0110] Based on the above embodiment, the detection module 402 is further used for: Obtain the battery temperature and internal pressure information of the battery during the relaxation period after each charge is completed during the charge and discharge cycle of the battery under test; Based on the voltage difference during the relaxation period corresponding to multiple charge and discharge cycles, the battery under test is tested for lithium deposition, including: Comparing the voltage difference with a first voltage threshold to obtain a first comparison result; Comparing the battery temperature with a temperature threshold to obtain a second comparison result; Comparing the internal pressure information of the battery with the pressure threshold to obtain a third comparison result; It is determined whether the amount of lithium deposition of the battery to be tested reaches a first lithium deposition level according to the first comparison result, the second comparison result and the third comparison result.

[0111] Figure 5 A schematic diagram of the physical structure of an electronic device provided in an embodiment of the present application, such as Figure 5 As shown, the electronic device includes: a processor (processor) 501, a memory (memory) 502 and a bus 503; wherein, The processor 501 and the memory 502 communicate with each other via the bus 503; The processor 501 is used to call the program instructions in the memory 502 to execute the methods provided by the above-mentioned method embodiments, for example, including: obtaining the voltage difference during the relaxation period after each charging is completed during the charge and discharge cycle of the battery to be tested; the relaxation period refers to the time period from the completion of charging to the recovery of the battery to be tested to a steady state; the voltage difference during the relaxation period is the difference between the voltage corresponding to the completion of charging of the battery to be tested and the voltage restored to a steady state; based on the voltage difference during the relaxation period corresponding to multiple charge and discharge cycles, the battery to be tested is subjected to lithium plating detection.

[0112] The processor 501 may be an integrated circuit chip with signal processing capability. The processor 501 may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it may 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 gates or transistor logic devices, discrete hardware components. It may implement or execute various methods, steps and logic block diagrams disclosed in the embodiments of the present application. A general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0113] 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.

[0114] The present embodiment discloses a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium, and the computer program includes program instructions. When the program instructions are executed by a computer, the computer can execute the methods provided by the above-mentioned method embodiments, for example, including: obtaining the voltage difference during the relaxation period of the battery to be tested after each charging is completed during the charge and discharge cycle; the relaxation period refers to the time period from the completion of charging to the recovery of the battery to be tested to a steady state; the voltage difference during the relaxation period is the difference between the voltage corresponding to the completion of charging of the battery to be tested and the voltage restored to a steady state; and performing lithium plating detection on the battery to be tested based on the voltage difference during the relaxation period corresponding to multiple charge and discharge cycles.

[0115] The present embodiment provides a non-transitory computer-readable storage medium, which stores computer instructions, and the computer instructions enable the computer to execute the methods provided by the above-mentioned method embodiments, for example, including: obtaining the voltage difference during the relaxation period of the battery to be tested after each charging is completed during the charge and discharge cycle; the relaxation period refers to the time period from the completion of charging to the recovery of the battery to be tested to a steady state; the voltage difference during the relaxation period is the difference between the voltage corresponding to the completion of charging of the battery to be tested and the voltage restored to a steady state; based on the voltage difference during the relaxation period corresponding to multiple charge and discharge cycles, the battery to be tested is subjected to lithium plating detection.

[0116] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, and the indirect coupling or communication connection of the devices or units can be electrical, mechanical or other forms.

[0117] In addition, the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0118] Furthermore, the functional modules in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

[0119] In this document, relational terms such as first and second, etc. are used merely to distinguish one entity or operation from another entity or operation, but do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0120] The above description is only an embodiment of the present application and is not intended to limit the protection scope of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for detecting lithium deposition in a battery, characterized in that: include: Obtaining the voltage difference during the relaxation period after each charging is completed during the charge and discharge cycle of the battery to be tested; the relaxation period refers to the time period from the completion of charging to the recovery of the battery to be tested to a steady state; the voltage difference during the relaxation period is the difference between the voltage corresponding to the completion of charging of the battery to be tested and the voltage restored to a steady state; The battery to be tested is subjected to lithium plating detection based on the voltage difference during the relaxation period corresponding to multiple charge and discharge cycles.

2. The method according to claim 1, characterized in that The method of performing lithium deposition detection on the battery to be tested based on the voltage difference during the relaxation period corresponding to multiple charge and discharge cycles includes: Generating a curve of the change of the voltage difference with the number of cycles based on the voltage difference corresponding to multiple charge and discharge cycles; When the change in the voltage difference is greater than or equal to a preset threshold, it is determined that lithium deposition occurs in the battery to be tested, and the number of cycles corresponding to the occurrence of lithium deposition is recorded.

3. The method according to claim 2, characterized in that The preset threshold includes a first preset threshold and a second preset threshold, and the first preset threshold is smaller than the second preset threshold; When the change in the voltage difference is greater than or equal to the first preset threshold, determining that the amount of lithium deposition of the battery to be tested is a first lithium deposition degree; When the change in the voltage difference is greater than or equal to the second preset threshold, determining that the amount of lithium deposition of the battery to be tested is a second lithium deposition degree; Among them, the first lithium precipitation degree is less than the second lithium precipitation degree.

4. The method according to claim 3, characterized in that The voltage difference change is determined to be greater than a preset threshold by at least one of the following: The difference between the voltage differences corresponding to two adjacent charge and discharge cycles is greater than a preset difference; Generating a voltage difference curve based on the voltage difference corresponding to multiple charge and discharge cycles, wherein the slope of the voltage difference curve is greater than a preset slope; A differential calculation is performed based on the voltage difference corresponding to multiple charge and discharge cycles, and the obtained differential value is greater than a preset differential value.

5. The method according to claim 1, characterized in that The step of obtaining the voltage difference during the relaxation period after each charge is completed during the charge and discharge cycle of the battery to be tested comprises: Charging the battery to be tested so that the state of charge of the battery to be tested after charging reaches a preset state of charge, and recording a first voltage of the battery to be tested after charging is completed; The charged battery to be tested is left to stand for a preset time, and a second voltage of the battery to be tested is recorded after the battery is left to stand; A voltage difference during the relaxation period is determined based on a voltage difference between the first voltage and the second voltage.

6. The method according to claim 5, characterized in that The step of charging the battery to be tested so that the state of charge of the battery to be tested reaches a preset state of charge includes: Performing constant current charging on the battery to be tested, so that the voltage of the battery to be tested after constant current charging reaches a charging cut-off voltage; The battery to be tested after constant current charging is charged at a constant voltage, so that the charge state of the battery to be tested after constant voltage charging reaches a preset charge state.

7. The method according to claim 5, characterized in that The value range of the preset duration is [10 minutes, 60 minutes].

8. The method according to claim 3, characterized in that The method further comprises: After determining that the lithium deposition amount of the battery to be tested is the first lithium deposition level, a water diving warning signal is output.

9. The method according to claim 1, characterized in that: The method further comprises: Collecting the charge and discharge parameters of the battery to be tested; the charge and discharge parameters include the charge and discharge rate, the rest time and the SOC corresponding to the completion of charge and discharge respectively; Inputting the charge and discharge parameters into a lithium deposition prediction model, and obtaining the number of charge and discharge cycles of the battery to be tested that causes a first lithium deposition degree to occur, output by the lithium deposition prediction model; The lithium precipitation prediction model is obtained by training using the following method: The test battery is charged and discharged using a variety of different charge and discharge parameters, and the training voltage difference during the relaxation period after each charge is completed is obtained; Determine, based on the training voltage difference, the number of charge and discharge cycles corresponding to the lithium deposition amount of the test battery reaching a first lithium deposition level; The charge and discharge parameters are used as model input, and the number of charge and discharge cycles is used as a label for model training to obtain a lithium precipitation prediction model.

10. The method according to any one of claims 1 to 9, characterized in that: The method further includes: obtaining the battery temperature and internal pressure information of the battery during the relaxation period after each charge is completed during the charge and discharge cycle of the battery to be tested; The method of performing lithium deposition detection on the battery to be tested based on the voltage difference during the relaxation period corresponding to multiple charge and discharge cycles includes: Comparing the voltage difference with a first voltage threshold to obtain a first comparison result; Comparing the battery temperature with a temperature threshold to obtain a second comparison result; Comparing the battery internal pressure information with a pressure threshold to obtain a third comparison result; Whether the lithium deposition amount of the battery to be tested reaches a first lithium deposition level is determined according to the first comparison result, the second comparison result and the third comparison result.

11. A battery lithium deposition detection device, characterized in that: include: A voltage difference acquisition module is used to obtain the voltage difference during the relaxation period after each charging of the battery under test during the charge and discharge cycle; the relaxation period refers to the time period from the completion of charging to the recovery of the battery under test to a steady state; the voltage difference during the relaxation period is the difference between the voltage corresponding to the completion of charging of the battery under test and the voltage restored to a steady state; The detection module is used to perform lithium deposition detection on the battery to be tested based on the voltage difference during the relaxation period corresponding to multiple charge and discharge cycles.

12. An electronic device, characterized in that: include: processor, memory and bus, wherein, 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 calls the program instructions to execute the method according to any one of claims 1 to 10.

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

14. A computer program product, characterized in that The method comprises computer program instructions, and when the computer program instructions are read and executed by a processor, the method according to any one of claims 1 to 10 is executed.

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