Battery lithium deposition detection method, device, electronic equipment and storage medium

Abstract

The present application discloses a method, device, electronic device and storage medium for detecting lithium deposition of a battery. The method for detecting lithium deposition of a battery comprises: obtaining voltage variation data that changes with time during a static period after the battery to be tested is charged at a preset rate; performing first-order differential processing on the voltage variation data to obtain a voltage differential curve of the battery to be tested; and obtaining the amount of irreversible lithium deposition that characterizes the battery to be tested at the target time point according to the target time point corresponding to the characteristic peak in the voltage differential curve and the capacity difference between the charging capacity corresponding to the current charging of the battery to be tested and the initial charging capacity of the battery to be tested. The method for detecting lithium deposition of a battery provided in the embodiment of the present application can quantitatively analyze the degree of lithium deposition of a battery.

Description

Technical Field

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

[0002] The lithium deposition problem of batteries is a common abnormality during the use of lithium-ion batteries. For the detection of lithium deposition of batteries, the voltage relaxation method can be used in related technologies to determine whether the battery has lithium deposition. However, this lithium deposition detection method can only perform a qualitative analysis of the lithium deposition of the battery, and cannot determine the degree of lithium deposition of the battery, resulting in an inability to accurately judge the risk of battery use. Summary of the invention

[0003] In view of the above problems, the present application provides a battery lithium plating detection method, device, electronic device and storage medium, which can quantitatively analyze the degree of lithium plating of the battery.

[0004] In a first aspect, the present application provides a method for detecting lithium plating of a battery, the method comprising: obtaining voltage change data that changes with time during a static period of time after the battery to be tested is charged at a preset rate; performing first-order differential processing on the voltage change data to obtain a voltage differential curve of the battery to be tested; and obtaining an amount of irreversible lithium plating that characterizes the battery to be tested at the target time point based on a target time point corresponding to a characteristic peak in the voltage differential curve and a capacity difference between a charging capacity corresponding to the current charging of the battery to be tested and an initial charging capacity of the battery to be tested.

[0005] In the technical scheme of the embodiment of the present application, by obtaining the voltage change data of the battery to be tested during the static period after the current charging is completed at a preset rate, the voltage change data is subjected to first-order differential processing to obtain the voltage differential curve of the battery to be tested, and according to the target time point corresponding to the characteristic peak in the voltage differential curve, and the capacity difference between the charging capacity corresponding to the current charging of the battery to be tested and the initial charging capacity of the battery to be tested, the irreversible lithium precipitation amount of the battery to be tested at the target time point is obtained. Since the voltage of the battery to be tested has the highest voltage value at the end of charging, with the beginning of static, the movement speed of the lithium ions in the battery to be tested will gradually decrease, and then the voltage of the battery will slowly decrease. If the battery to be tested has lithium precipitation, part of the lithium crystals precipitated on the surface of the anode will be re-embedded into the anode, delaying the decline in voltage, and the corresponding first-order differential curve will have a characteristic peak at this time, and the target time point corresponding to the characteristic peak can represent the time point when the lithium crystal ends the back embedding, so the irreversible lithium precipitation amount of the battery to be tested at the target time point can be determined by using the charging capacity corresponding to the current charging of the battery to be tested and the capacity difference between the initial charging capacity of the battery to be tested. This enables quantitative analysis of the degree of lithium plating in the battery, and thus accurately determines the risk of battery use.

[0006] In some embodiments, the method further includes: controlling the battery to be tested to be charged at a preset rate every preset number of cycles; wherein the preset number of cycles includes the number of cycles of charge and discharge cycles of the battery to be tested at a charging rate greater than the preset rate. This can reduce invalid detection of the battery to be tested and improve the efficiency of lithium plating detection of the battery to be tested.

[0007] In some embodiments, the method further includes: determining the initial number of cycles corresponding to the battery type according to the battery type of the battery to be tested; adjusting the initial number of cycles according to the comparison result of the irreversible lithium capacity measured by the battery sample with the same battery type as the battery to be tested when charging is completed at the preset rate after the initial number of cycles, and obtaining the preset number of cycles; wherein, if it is determined that the irreversible lithium capacity measured by the battery sample when charging is completed at the preset rate after the initial number of cycles is greater than the preset lithium capacity, the initial number of cycles is reduced; or, if it is determined that the irreversible lithium capacity measured by the battery sample when charging is completed at the preset rate after the initial number of cycles is less than the preset lithium capacity, the initial number of cycles is increased. Thus, the preset number of cycles is closer to the actual number of charge and discharge cycles when lithium deposition occurs in the battery to be tested, so that lithium deposition detection can be performed on the battery to be tested more timely.

[0008] In some embodiments, the method further includes: updating the preset number of cycles according to the number of times the battery to be tested is charged at the preset rate; wherein the number of times is negatively correlated with the preset number of cycles. Thus, according to the attenuation law of the battery to be tested, the period of charging the battery to be tested at the preset rate can be shortened, that is, the period of lithium plating detection of the battery to be tested can be shortened, thereby improving the timeliness of lithium plating detection of the battery to be tested.

[0009] In some embodiments, the amount of irreversible lithium deposition characterizing the battery under test at the target time point is obtained according to the target time point corresponding to the characteristic peak in the voltage differential curve, and the capacity difference between the charging capacity corresponding to the current charging of the battery under test and the initial charging capacity of the battery under test, including: when it is determined that the battery under test has lithium deposition according to the voltage change data, the amount of irreversible lithium deposition characterizing the battery under test at the target time point is obtained according to the target time point corresponding to the characteristic peak in the voltage differential curve and the capacity difference. Thus, when it is determined that the battery under test has lithium deposition according to the voltage change data, the amount of irreversible lithium deposition of the battery under test at the target time point corresponding to the characteristic peak in the voltage differential curve is detected again, so as to reduce the number of invalid detections of the amount of lithium deposition of the battery under test, thereby improving the detection efficiency of the amount of lithium deposition of the battery under test.

[0010] In some embodiments, when it is determined that the battery to be tested has lithium deposition according to the voltage differential curve, the irreversible lithium deposition amount of the battery to be tested at the target time point is obtained according to the target time point corresponding to the characteristic peak in the voltage differential curve and the capacity difference. Since the voltage differential curve obtained by performing a first-order differential process on the voltage change data can be used to reflect the rate of change of the voltage change data, by detecting the voltage differential curve obtained by performing a first-order differential process on the voltage change data, it is possible to better judge whether the voltage change data has fluctuations, thereby being able to more accurately determine whether the battery to be tested has lithium deposition.

[0011] In some embodiments, obtaining the lithium deposition detection result of the battery to be tested according to the voltage change data includes: performing high-order differential processing on the voltage change data to obtain the differential processing result corresponding to the voltage change data. When it is determined that the battery to be tested has lithium deposition according to the differential processing result, the irreversible lithium deposition amount of the battery to be tested at the target time point is obtained according to the target time point corresponding to the characteristic peak in the voltage differential curve and the capacity difference. Thereby, it can be effectively determined whether the battery to be tested has lithium deposition.

[0012] In some embodiments, according to the target time point corresponding to the characteristic peak in the voltage differential curve, and the capacity difference between the charging capacity corresponding to the current charging of the battery to be tested and the initial charging capacity of the battery to be tested, the amount of irreversible lithium deposition characterizing the battery to be tested at the target time point is obtained, including: performing high-order differential processing on the voltage differential curve to determine each inflection point in the voltage differential curve; determining the characteristic peak in the voltage differential curve according to the differential value corresponding to each inflection point in the voltage differential curve; according to the target time point corresponding to the characteristic peak in the voltage differential curve and the capacity difference, obtaining the amount of irreversible lithium deposition characterizing the battery to be tested at the target time point.

[0013] In a second aspect, the present application provides a battery lithium deposition detection device, comprising: a voltage data acquisition module, used to obtain voltage change data that changes with time during a static period of the battery to be tested after the current charging is completed at a preset rate; a voltage data processing module, used to perform first-order differential processing on the voltage change data to obtain a voltage differential curve of the battery to be tested; a battery lithium deposition detection module, used to obtain a characterization of the irreversible lithium deposition amount of the battery to be tested at the target time point based on a target time point corresponding to a characteristic peak in the voltage differential curve and a capacity difference between the charging capacity corresponding to the current charging of the battery to be tested and the initial charging capacity of the battery to be tested.

[0014] In the technical solution of the embodiment of the present application, the solution obtains the voltage change data of the battery to be tested during the static period after the battery to be tested is charged at a preset rate, and performs first-order differential processing on the voltage change data to obtain the voltage differential curve of the battery to be tested, and obtains the irreversible lithium precipitation amount of the battery to be tested at the target time point according to the target time point corresponding to the characteristic peak in the voltage differential curve, and the capacity difference between the charging capacity corresponding to the current charging of the battery to be tested and the initial charging capacity of the battery to be tested. Thereby, the quantitative analysis of the degree of lithium precipitation of the battery can be realized, and the use risk of the battery can be accurately judged.

[0015] In some embodiments, the voltage data acquisition module is also used to: control the battery to be tested to be charged at the preset rate every preset number of cycles; wherein the preset number of cycles includes the number of charge and discharge cycles of the battery to be tested using a charging rate greater than the preset rate.

[0016] In some embodiments, the voltage data acquisition module is further used to: determine the initial number of cycles corresponding to the battery type according to the battery type of the battery to be tested; and adjust the initial number of cycles to obtain the preset number of cycles by comparing the irreversible lithium capacity measured when charging is completed at the preset rate at intervals of the initial number of cycles with the battery sample having the same battery type as the battery to be tested and the preset lithium capacity;

[0017] Among them, it is determined that the irreversible lithium capacity of the battery sample measured when charging is completed at the preset rate after an interval of the initial number of cycles is greater than the preset lithium capacity, and the initial number of cycles is reduced; or it is determined that the irreversible lithium capacity of the battery sample measured when charging is completed at the preset rate after an interval of the initial number of cycles is less than the preset lithium capacity, and the initial number of cycles is increased.

[0018] In some embodiments, the voltage data acquisition module is further used to: update the preset number of cycles according to the number of times the battery to be tested is charged using the preset rate; wherein the number of times of charging is negatively correlated with the preset number of cycles.

[0019] In some embodiments, the battery lithium deposition detection module is specifically used to: when it is determined that lithium deposition exists in the battery to be tested according to the voltage change data, obtain the amount of irreversible lithium deposition that characterizes the battery to be tested at the target time point according to the target time point corresponding to the characteristic peak in the voltage differential curve and the capacity difference.

[0020] In some embodiments, the battery lithium deposition detection module is specifically used to: when it is determined that lithium deposition occurs in the battery to be tested according to the voltage differential curve, obtain the amount of irreversible lithium deposition that characterizes the battery to be tested at the target time point according to the target time point corresponding to the characteristic peak in the voltage differential curve and the capacity difference.

[0021] In some embodiments, the battery lithium deposition detection module is specifically used to: perform high-order differential processing on the voltage change data to obtain a differential processing result corresponding to the voltage change data; when it is determined that lithium deposition exists in the battery to be tested according to the differential processing result, obtain the amount of irreversible lithium deposition that characterizes the battery to be tested at the target time point according to the target time point corresponding to the characteristic peak in the voltage differential curve and the capacity difference.

[0022] In some embodiments, the battery lithium deposition detection module is specifically used to: perform high-order differential processing on the voltage differential curve to determine each inflection point in the voltage differential curve; determine a characteristic peak in the voltage differential curve according to the differential value corresponding to each inflection point in the voltage differential curve; and obtain the amount of irreversible lithium deposition that characterizes the battery to be tested at the target time point according to the target time point corresponding to the characteristic peak in the voltage differential curve and the capacity difference.

[0023] In a third aspect, the present application provides an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor executes the method in the implementation of the first aspect when executing the computer program.

[0024] In a fourth aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, performs the method in the implementation of the first aspect.

[0025] In a fifth aspect, the present application provides a computer program product, which, when running on a computer, enables the computer to execute the method in the first aspect or any optional implementation manner of the first aspect.

[0026] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0028] Figure 1 A first flow chart of a method for detecting lithium deposition in a battery according to some embodiments of the present application;

[0029] Figure 2 A schematic diagram of a voltage differential curve of some embodiments of the present application;

[0030] Figure 3 A schematic diagram of a charging capacity variation curve of some embodiments of the present application;

[0031] Figure 4 A schematic diagram of a battery capacity loss curve of some embodiments of the present application;

[0032] Figure 5 A second flow chart of a method for detecting lithium deposition in a battery according to some embodiments of the present application;

[0033] Figure 6 A schematic diagram of the structure of a battery lithium deposition detection device according to some embodiments of the present application;

[0034] Figure 7 This is a schematic diagram of the structure of an electronic device according to some embodiments of the present application.

[0035] The reference numerals in the specific implementation manner are as follows:

[0036] 300 - voltage data acquisition module; 301 - voltage data processing module; 302 - battery lithium deposition detection module; 400 - electronic device; 401 - processor; 402 - memory; 403 - communication bus. DETAILED DESCRIPTION

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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).

[0043] The lithium plating problem of batteries is a common anomaly during the use of lithium-ion batteries. If lithium plating occurs in the battery, it will cause the battery capacity to decay, accelerate battery aging, and affect the use of the battery. Therefore, it is usually necessary to perform lithium plating detection on the battery to detect batteries with the risk of lithium plating. At present, for the lithium plating detection of batteries, it is usually carried out by disassembling the battery and observing it to determine whether lithium plating occurs. However, this method has problems such as damage to the battery, poor safety, and the inability to quantify the degree of lithium plating through visual inspection.

[0044] To this end, in the related art, the voltage relaxation method can be used to determine whether the battery has lithium deposition. For example, after the battery is charged and discharged for a cycle, the change in the open circuit voltage of the battery within a set time is measured to determine whether the battery has lithium deposition. However, this battery lithium deposition detection method can only perform a qualitative analysis of the battery's lithium deposition, and cannot determine the degree of lithium deposition of the battery, resulting in an inability to accurately determine the risk of battery use.

[0045] In response to the above technical problems, an embodiment of the present application provides a method for detecting lithium deposition of a battery, which obtains the voltage change data of the battery to be tested during the static period after the battery to be tested is charged at a preset rate, performs first-order differential processing on the voltage change data, obtains the voltage differential curve of the battery to be tested, and obtains the irreversible lithium deposition amount of the battery to be tested at the target time point according to the target time point corresponding to the characteristic peak in the voltage differential curve, and the capacity difference between the charging capacity corresponding to the current charging of the battery to be tested and the initial charging capacity of the battery to be tested. Since the voltage of the battery to be tested has the highest voltage value at the end of charging, with the beginning of static, the movement speed of lithium ions in the battery to be tested will gradually decrease, and then the voltage of the battery will slowly decrease. If the battery to be tested has lithium deposition, some lithium crystals deposited on the anode surface will be re-embedded into the anode, delaying the voltage drop. At this time, the corresponding first-order differential curve will have a characteristic peak, and the target time point corresponding to the characteristic peak can indicate the time point when the lithium crystals end their re-embedding. Therefore, the capacity difference between the charging capacity corresponding to the current charging of the battery to be tested and the initial charging capacity of the battery to be tested can be used to determine the amount of irreversible lithium deposition of the battery to be tested at the target time point. This can achieve quantitative analysis of the degree of lithium deposition in the battery, and can accurately determine the risk of battery use.

[0046] The battery lithium deposition detection method, device, electronic device and storage medium disclosed in the embodiments of the present application can be applied to a terminal device to detect the amount of lithium deposition of the battery to be tested. The terminal device can be any terminal device such as a mobile terminal, a desktop terminal, a vehicle-mounted terminal or a server. The server can be an independent server or a server cluster composed of multiple servers, and can also be a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, CDN, and big data and artificial intelligence sampling point devices.

[0047] According to some embodiments of the present application, a method for detecting lithium deposition in a battery according to one embodiment of the present application can be applied to the aforementioned terminal device. Figure 1 As shown, the lithium plating detection method of the battery includes:

[0048] S101, obtaining voltage change data of the battery under test that changes with time during a static period after the battery is charged at a preset rate;

[0049] S102, performing first-order differential processing on the voltage change data to obtain a voltage differential curve of the battery to be tested;

[0050] S103, obtaining an irreversible lithium deposition amount characterizing the battery under test at the target time point according to the target time point corresponding to the characteristic peak in the voltage differential curve and the capacity difference between the charging capacity corresponding to the current charging of the battery under test and the initial charging capacity of the battery under test.

[0051] In some embodiments, the battery to be tested may include a lithium-ion battery, such as a lithium iron phosphate, lithium iron manganese phosphate or lithium manganate battery. The battery to be tested may include a single battery cell or multiple battery cells, and each battery cell may be connected in series, in parallel or in a mixed manner to form the battery to be tested.

[0052] The terminal device can be connected to a power supply for charging the battery to be tested to control the power supply to charge the battery to be tested. When the battery needs to be tested for lithium deposition, the terminal device can control the power supply to charge the battery to be tested at a preset rate, such as controlling the power supply to charge the battery to be tested at a preset rate for constant current. The preset rate is a small rate that makes the loss of the battery to be tested less than the preset loss. For example, when the preset rate can be less than or equal to the battery to be tested is charged to a cut-off voltage, the charging rate when the cut-off voltage is used to charge the battery to be tested at a constant voltage. Exemplarily, the preset charging rate may be less than or equal to 0.05C.

[0053] After the preset rate is used to complete the current charging of the battery to be tested, the charging is terminated, and the battery to be tested is placed in a static state. The static state may refer to that the battery to be tested is neither charged nor discharged, and is in a non-working state. Since the voltage of the battery is unstable for a certain period of time when the charging of the battery has just ended, there will be a more obvious drop. Therefore, during the static period when the battery to be tested is in a static state, the open circuit voltage of the battery to be tested may be detected to obtain voltage change data of the battery to be tested that changes with time during the static period, such as a time-open circuit voltage curve. The duration of the static period may be set according to actual conditions, such as being determined according to the voltage relaxation time of the battery to be tested after charging is completed. Exemplarily, the duration of the static period may be greater than or equal to 1 hour.

[0054] After obtaining the voltage change data of the battery to be tested, the voltage change data can be subjected to first-order differential processing, that is, the voltage change data is subjected to first-order derivative calculation to obtain a voltage differential curve of the battery to be tested that changes with time, such as a -dV / dT curve.

[0055] Since the voltage of the battery under test is the highest at the end of charging, the movement speed of lithium ions in the battery under test will gradually decrease as it begins to rest, and the battery voltage will slowly drop. If lithium deposition occurs in the battery under test, some lithium crystals deposited on the anode surface will be re-embedded into the anode, delaying the voltage drop, causing the voltage change data of the battery under test to rebound during the resting process, and return to the normal downward trend after the lithium ions are re-embedded. At this time, a characteristic peak will appear in the voltage differential curve corresponding to the voltage change data, such as Figure 2 As shown in FIG. 1 , the fluctuation peak value of the voltage differential curve, that is, the time point t corresponding to the characteristic peak A, can represent the time point when the lithium ions are completely reinserted, that is, the target time point. At this time, the amount of lithium precipitation at the target time point is the irreversible amount of lithium precipitation, that is, the amount of dead lithium.

[0056] Therefore, after obtaining the voltage differential curve of the battery to be tested, the voltage differential curve can be detected from small to large along the time axis to obtain each inflection point in the voltage differential curve. Among them, for the detection of any inflection point in the voltage differential curve, it can be to derive each data point in the voltage differential curve except the endpoint, and obtain the data point in the voltage differential curve where the second-order derivative is 0, which is the inflection point in the voltage differential curve. Alternatively, other conventional inflection point detection methods can be used to determine the inflection points in the voltage differential curve. After determining each inflection point in the voltage differential curve, the characteristic peak of the voltage differential curve can be obtained according to the -dV / dT value corresponding to each inflection point.

[0057] After obtaining the characteristic peak of the voltage differential curve, the time point corresponding to the characteristic peak, that is, the target time point, can be determined according to the voltage differential curve, and the charging capacity C1 corresponding to the current charging of the battery to be tested is obtained. After obtaining the initial charging capacity C0 of the battery to be tested, the difference Cir between the initial charging capacity C0 and the charging capacity C1 is obtained to obtain the irreversible lithium capacity of the battery to be tested at the target time point, so as to characterize the irreversible lithium deposition amount of the battery to be tested at the target time point.

[0058] The initial charging capacity of the battery to be tested may be obtained by charging the battery to be tested for the first time at a preset rate, and determining the charging capacity of the battery to be tested measured after the first charging is completed as the initial charging capacity of the battery to be tested.

[0059] The above-designed battery lithium deposition detection method obtains the voltage change data that changes with time during the static period after the battery to be tested is charged at a preset rate, performs first-order differential processing on the voltage change data, obtains the voltage differential curve of the battery to be tested, and obtains the irreversible lithium deposition amount of the battery to be tested at the target time point according to the target time point corresponding to the characteristic peak in the voltage differential curve, and the capacity difference between the charging capacity corresponding to the current charging of the battery to be tested and the initial charging capacity of the battery to be tested. Since the voltage of the battery to be tested has the highest voltage value at the end of charging, with the beginning of static, the movement speed of lithium ions in the battery to be tested will gradually decrease, and then the voltage of the battery will slowly decrease. If the battery to be tested has lithium deposition, part of the lithium crystals deposited on the surface of the anode will be re-embedded into the anode, delaying the drop in voltage, and the corresponding first-order differential curve will have a characteristic peak at this time, and the target time point corresponding to the characteristic peak can represent the time point when the lithium crystals end to be re-embedded, so the irreversible lithium deposition amount of the battery to be tested at the target time point can be determined by using the charging capacity corresponding to the current charging of the battery to be tested and the capacity difference between the initial charging capacity of the battery to be tested. This enables quantitative analysis of the degree of lithium plating in the battery, and thus accurately determines the risk of battery use.

[0060] Taking into account that the amount of lithium deposition of a battery will only show obvious changes after multiple charge and discharge cycles, in order to reduce invalid detection of the battery to be tested and improve the lithium deposition detection efficiency of the battery to be tested, in some embodiments, the method also includes: controlling the battery to be tested to be charged at a preset rate every preset number of cycles; wherein the preset number of cycles includes the number of charge and discharge cycles of the battery to be tested using a charging rate greater than the preset rate.

[0061] The preset number of cycles can be set according to actual conditions. For example, a battery sample of the same type as the battery to be tested can be subjected to multiple charge and discharge cycles, i.e., multiple charge and discharge cycles, using a conventional charge and discharge rate greater than a preset rate, such as a 1C charge rate. The battery type includes the type and model of the battery. For example, the battery type may include lithium iron phosphate battery, ternary lithium battery, lithium iron manganese phosphate battery, or lithium manganate battery.

[0062] After each charge and discharge cycle, the charge capacity of the battery sample is recorded. If after this charge and discharge cycle, the charge capacity of the battery sample is significantly reduced compared with the charge capacity measured in the previous charge and discharge cycle, the number of cycles corresponding to this charge and discharge cycle can be determined as the preset number of cycles. If it is assumed that after each charge and discharge cycle, the charge capacity of the battery sample measured is Figure 3 As shown, the irreversible lithium capacity loss of the battery samples is as follows Figure 4As shown, it can be determined that when the cycle reaches 300-350 cycles, the charging capacity of the battery sample decreases significantly and the battery capacity loss increases sharply. It can be determined that the battery sample is likely to have lithium plating when the charge and discharge cycle number is 300-350 cycles. Therefore, the preset cycle number can be set to any number between 300-350 cycles.

[0063] After determining the preset number of cycles, the battery to be tested can be controlled to charge at a preset rate every preset number of cycles. For example, the battery to be tested can be controlled to use a charging rate greater than the preset rate, such as a charging rate of 1C for 350 charge and discharge cycles, and the next charge is performed at the preset rate to perform a lithium deposition test on the battery. Exemplarily, assuming that the battery to be tested has reached the warranty period and needs to be tested for lithium deposition, and the preset number of cycles is 350 charge and discharge cycles, the power supply can be controlled to use a charging rate greater than the preset rate, such as a charging rate of 1C, to perform a charge and discharge cycle on the battery to be tested, until the number of charge and discharge cycles of the battery to be tested using the charging rate reaches 350, then the power supply is controlled to reduce the charging rate to the preset rate, and the battery to be tested is charged once using the preset rate, so as to obtain the voltage change data of the battery to be tested during the static period after the charging is completed using the preset rate, which changes with time, to perform a lithium deposition test on the battery.

[0064] Alternatively, assuming that the battery to be tested is a normally used battery, the number of charge and discharge cycles of the battery to be tested using a charging rate greater than a preset rate can be recorded, and the recorded number of cycles can be detected. If it is detected that the recorded number of cycles reaches the preset number of cycles, such as 350 cycles, then when the battery to be tested is charged for the next time, the battery to be tested is charged once at the preset rate to obtain the voltage change data of the battery to be tested that changes with time during the static period after the battery to be tested is charged at the preset rate, so as to perform a lithium plating test on the battery. After the battery to be tested is charged once at the preset rate, the recorded number of cycles is cleared, and the number of charge and discharge cycles of the battery to be tested using a charging rate greater than the preset rate is re-recorded.

[0065] By controlling the battery to be tested to charge at a preset rate with a smaller charging rate every preset number of cycles, the voltage change data of the battery to be tested that changes with time during the static period after the charging is completed at the preset rate is obtained, and lithium plating detection is performed, thereby reducing invalid detection of the battery to be tested and improving the lithium plating detection efficiency of the battery to be tested.

[0066] When the battery to be tested is controlled to charge at a preset rate every preset number of cycles, it is possible that lithium deposition has occurred in the battery to be tested in a certain charge and discharge cycle, but the number of charge and discharge cycles of the battery to be tested has not reached the preset number of cycles, resulting in a significant delay in the lithium deposition detection of the battery to be tested. For example, if the preset number of cycles is set to 350, and lithium deposition has occurred in the battery to be tested when the charge and discharge cycle reaches 300, the lithium deposition detection of the battery to be tested will be delayed.

[0067] To this end, in some embodiments, the method further includes: determining an initial number of cycles corresponding to the battery type according to the battery type of the battery to be tested; adjusting the initial number of cycles to obtain the preset number of cycles according to a comparison result of the irreversible lithium capacity measured by a battery sample of the same battery type as the battery to be tested when charging is completed at the preset rate after the initial number of cycles, and obtaining the preset number of cycles; wherein, if it is determined that the irreversible lithium capacity measured by the battery sample when charging is completed at the preset rate after the initial number of cycles is greater than the preset lithium capacity, the initial number of cycles is reduced; or, if it is determined that the irreversible lithium capacity measured by the battery sample when charging is completed at the preset rate after the initial number of cycles is less than the preset lithium capacity, the initial number of cycles is increased.

[0068] In some embodiments, since batteries of different battery types have different attenuation efficiencies, corresponding numbers of cycles can be set for batteries of different battery types, and the correspondence between the battery type and the number of cycles can be recorded to form a mapping table recording the correspondence between the battery type and the number of cycles. The number of cycles is the number of charge and discharge cycles of the battery using a charging rate greater than a preset rate. For example, for batteries with slower attenuation, such as lithium iron phosphate batteries, a larger number of cycles, such as 350, can be set, while for batteries with faster attenuation, such as lithium manganese oxide batteries, a smaller number of cycles, such as 300, can be set.

[0069] After setting the number of cycles corresponding to different battery types, for a battery sample of any battery type, the battery sample can be charged and discharged using the corresponding number of cycles, and then the battery sample can be charged at a small rate using a preset rate, so that the amount of lithium deposition measured by the battery sample after this charging can be used as the irreversible lithium capacity measured by the battery sample when the battery sample is charged at the preset rate after the number of cycles. Exemplarily, the battery sample can be charged at a small rate using a preset rate, and its initial charging capacity C0' can be measured and recorded, and then the battery sample can be charged and discharged using the corresponding number of cycles, and then the battery sample can be charged at a small rate using a preset rate, and its charging capacity C1' after this charging is completed can be measured, so as to obtain the irreversible lithium capacity Cir'=C0'-C1' measured by the battery sample when the number of cycles is separated and the charging is completed using the preset rate, based on the initial charging capacity C0' and the charging capacity C1'.

[0070] After the irreversible lithium capacity is obtained, the irreversible lithium capacity and the number of cycles can be mapped and recorded in a mapping table, thereby obtaining a mapping table recording the correspondence between the battery type, the number of cycles and the irreversible lithium capacity.

[0071] For the battery to be tested, the number of cycles corresponding to the battery type of the battery to be tested can be obtained from the mapping table according to its battery type as the initial number of cycles, and the irreversible lithium capacity corresponding to the initial number of cycles in the mapping table is detected to be greater than or equal to the preset lithium capacity. Among them, the preset lithium capacity can be set according to the actual situation, such as the critical value of the irreversible lithium capacity measured when the battery has lithium deposition. That is, when lithium deposition occurs in the battery, the measured irreversible lithium capacity is greater than or equal to the preset lithium capacity; when lithium deposition does not occur in the battery, the measured irreversible lithium capacity is less than the preset lithium capacity. The preset lithium capacity corresponding to different battery types is different, which can be determined based on a large number of lithium deposition tests.

[0072] If the irreversible lithium capacity corresponding to the initial cycle number in the mapping table is greater than the preset lithium capacity, it means that the battery of the same type as the battery to be tested has lithium plating before the number of charge and discharge cycles reaches the initial cycle number. At this time, the initial cycle number can be reduced to obtain the preset cycle number, so as to control the battery to be tested to be charged at the preset rate every preset cycle number. If the irreversible lithium capacity corresponding to the initial cycle number in the mapping table is less than the preset lithium capacity, it means that the battery of the same type as the battery to be tested has lithium plating before the number of charge and discharge cycles reaches the initial cycle number. Lithium deposition will occur only after the initial number of cycles. At this time, the initial number of cycles can be increased to obtain the preset number of cycles, so as to control the battery to be tested to be charged at the preset rate every preset number of cycles; if the irreversible lithium capacity corresponding to the initial number of cycles in the mapping table is equal to the preset lithium capacity, it means that the battery of the same battery type as the battery to be tested will have lithium deposition when the number of charge and discharge cycles reaches the initial number of cycles. At this time, the initial number of cycles can be determined as the preset number of cycles, so as to control the battery to be tested to be charged at the preset rate every preset number of cycles. Thereby, the preset number of cycles is closer to the actual number of charge and discharge cycles when lithium deposition occurs in the battery to be tested, so that the battery to be tested can be tested for lithium deposition in a more timely manner.

[0073] In order to further improve the timeliness of lithium plating detection on the battery to be tested, in some embodiments, the method further includes: updating the preset number of cycles according to the number of times the battery to be tested is charged using the preset rate; wherein the number of charging times is negatively correlated with the preset number of cycles.

[0074] Considering that the attenuation rate will increase with the increase of the number of charge and discharge cycles of the battery, the number of times the battery to be tested is charged at a preset rate can be detected, that is, the number of times the battery to be tested is tested for lithium deposition. If the number of charging times is larger, it means that the number of charge and discharge cycles of the battery to be tested is also larger, and the possibility of early lithium deposition is greater. At this time, the preset number of cycles is reduced. That is, the preset number of cycles decreases as the number of times the battery to be tested is tested for lithium deposition increases.

[0075] Exemplarily, assuming that the preset number of cycles is initially set to 300, and the number of times the battery to be tested is charged at the preset rate except for the first charge is zero, it means that the battery to be tested has not been subjected to lithium plating detection. At this time, the battery to be tested can be controlled to be charged once at the preset rate when the number of charge and discharge cycles reaches the preset number of cycles initially set, that is, 300 cycles. At the same time, according to the preset number of cycles ratio, the preset number of cycles is reduced to use the reduced preset number of cycles as the new preset number of cycles, such as reducing the preset number of cycles from 300 to 150, and using the 150 cycles as the new preset number of cycles, so as to control the battery to be tested to be charged once at the preset rate when the number of charge and discharge cycles reaches the new preset number of cycles, that is, 150, and so on. Until the updated preset number of cycles reaches the target number of cycles, such as 20 or 10, the preset number of cycles can no longer be updated. Therefore, according to the attenuation law of the battery to be tested, the charging cycle of the battery to be tested at a preset rate can be shortened, that is, the lithium plating detection cycle of the battery to be tested can be shortened, thereby improving the timeliness of the lithium plating detection of the battery to be tested.

[0076] In order to reduce invalid detection of the amount of lithium deposition of the battery to be tested, in some embodiments, according to the target time point corresponding to the characteristic peak in the voltage differential curve, and the capacity difference between the charging capacity corresponding to the current charging of the battery to be tested and the initial charging capacity of the battery to be tested, the amount of irreversible lithium deposition characterizing the battery to be tested at the target time point is obtained, including: when it is determined that lithium deposition exists in the battery to be tested according to the voltage change data, according to the target time point corresponding to the characteristic peak in the voltage differential curve and the capacity difference, the amount of irreversible lithium deposition characterizing the battery to be tested at the target time point is obtained.

[0077] As a possible implementation method, during the static period when the battery to be tested is charged at a preset rate, as the static period begins, the movement speed of lithium ions in the battery to be tested will gradually decrease, and then the voltage of the battery will slowly decrease. If the battery to be tested has lithium deposition, some lithium crystals deposited on the surface of the anode will be re-embedded in the anode, delaying the voltage drop, so that the voltage change data of the battery to be tested appears in a platform interval or a rebound interval, which is different from the voltage change data of a normal battery. Among them, a normal battery refers to a battery of the same battery type as the battery to be tested. Therefore, the voltage change data of a normal battery without lithium deposition during the static period after charging at a preset rate can be obtained first, and the voltage change data of the normal battery over time can be compared with the voltage change data of the battery to be tested over time to determine whether the battery to be tested has lithium deposition. If the voltage change data of the battery to be tested matches the voltage change data of the normal battery, such as the similarity reaches 90%, it can be determined that the battery to be tested is a normal battery and there is no lithium deposition; otherwise, it can be determined that the battery to be tested is an abnormal battery and there is lithium deposition.

[0078] After determining whether the battery to be tested has lithium deposition, if there is no lithium deposition, the detection of the amount of lithium deposition of the battery to be tested can be stopped. If there is lithium deposition, then the irreversible lithium deposition amount of the battery to be tested at the target time point is obtained based on the target time point corresponding to the characteristic peak in the voltage differential curve, and the capacity difference between the charging capacity corresponding to the current charging of the battery to be tested and the initial charging capacity of the battery to be tested. Thus, when it is determined that the battery to be tested has lithium deposition according to the voltage change data, the amount of irreversible lithium deposition of the battery to be tested at the target time point corresponding to the characteristic peak in the voltage differential curve is detected, thereby reducing the number of invalid detections of the amount of lithium deposition of the battery to be tested, and thereby improving the detection efficiency of the amount of lithium deposition of the battery to be tested.

[0079] Considering that a certain degree of depolarization will occur during the static process of the battery to be tested, this depolarization will have a certain impact on the voltage of the battery. Therefore, when the platform interval or rebound interval of the voltage change data is not obvious, due to the influence of depolarization, the platform interval or rebound interval of the voltage change data may disappear or be indistinguishable, so that if the voltage change data is directly used to detect whether the battery has lithium deposition, the lithium deposition phenomenon may not be accurately detected. To this end, in some embodiments, according to the target time point corresponding to the characteristic peak in the voltage differential curve, and the capacity difference between the charging capacity corresponding to the current charging of the battery to be tested and the initial charging capacity of the battery to be tested, the irreversible lithium deposition amount of the battery to be tested at the target time point is obtained, including: when it is determined that the battery to be tested has lithium deposition according to the voltage differential curve, according to the target time point corresponding to the characteristic peak in the voltage differential curve and the capacity difference, the irreversible lithium deposition amount of the battery to be tested at the target time point is obtained.

[0080] As a possible implementation, if lithium deposition exists in the battery to be tested, a characteristic peak will appear in the voltage differential curve obtained by first-order differentiation of the voltage change data, which is different from the voltage differential curve of a normal battery without lithium deposition. Therefore, the voltage change data of a normal battery without lithium deposition that changes with time during the static period after charging at a preset rate can be obtained first, and the voltage change data can be processed by first-order differentiation to obtain the voltage differential curve of the normal battery. Then, the voltage differential curve of the battery to be tested is compared with the voltage differential curve of the normal battery to determine whether lithium deposition exists in the battery to be tested. If the voltage differential curve of the battery to be tested is consistent with the voltage differential curve of the normal battery, it can be determined that the battery to be tested is a normal battery, and its lithium deposition detection result is that there is no lithium deposition; otherwise, it can be determined that the battery to be tested is abnormal, and its lithium deposition detection result is that there is lithium deposition.

[0081] As another possible implementation, if there is no lithium deposition in the battery to be tested, the voltage differential curve obtained after the first-order differentiation of its voltage change data is usually a monotonic curve, and the dV / dt value corresponding to each time point t is different. If there is lithium deposition in the battery to be tested, its voltage differential curve will fluctuate, resulting in a dV / dt value rebound in the voltage differential curve of the battery to be tested, that is, there are two different time points t corresponding to the same dV / dt value. Therefore, it is possible to detect whether there are two identical dV / dt values ​​in the voltage differential curve of the battery to be tested, that is, to determine whether f(t)=dI / dt=f(t+n). If not, it means that the voltage differential curve is a monotonic curve. At this time, it can be determined that the battery to be tested is a normal battery, and its lithium deposition detection result is that there is no lithium deposition phenomenon; otherwise, it can be determined that the battery to be tested is abnormal, and its lithium deposition detection result is that there is lithium deposition phenomenon.

[0082] After determining whether the battery to be tested has lithium deposition, if there is no lithium deposition, the detection of the amount of lithium deposition of the battery to be tested can be stopped. If there is lithium deposition, the irreversible lithium deposition amount of the battery to be tested at the target time point is obtained based on the target time point corresponding to the characteristic peak in the voltage differential curve and the capacity difference between the charging capacity corresponding to the current charging of the battery to be tested and the initial charging capacity of the battery to be tested.

[0083] Since the voltage differential curve obtained by performing the first-order differential processing on the voltage change data can be used to reflect the change rate of the voltage change data, by detecting the voltage differential curve obtained by performing the first-order differential processing on the voltage change data, it is possible to better judge whether there is fluctuation in the voltage change data, thereby being able to more accurately determine whether there is lithium deposition in the battery to be tested. When it is determined that lithium deposition exists in the battery to be tested according to the voltage differential curve, the amount of irreversible lithium deposition of the battery to be tested at a target time point corresponding to a characteristic peak in the voltage differential curve is detected, thereby reducing the number of invalid detections of the lithium deposition amount of the battery to be tested, thereby improving the detection efficiency of the lithium deposition amount detection of the battery to be tested.

[0084] In order to more effectively determine the lithium deposition test result of the battery to be tested, in some embodiments, according to the target time point corresponding to the characteristic peak in the voltage differential curve, and the capacity difference between the charging capacity corresponding to the current charging of the battery to be tested and the initial charging capacity of the battery to be tested, the irreversible lithium deposition amount characterizing the battery to be tested at the target time point is obtained, including:

[0085] Performing high-order differential processing on the voltage change data to obtain a differential processing result corresponding to the voltage change data;

[0086] When it is determined that lithium deposition occurs in the battery under test according to the differential processing result, the irreversible lithium deposition amount of the battery under test at the target time point is obtained according to the target time point corresponding to the characteristic peak in the voltage differential curve and the capacity difference.

[0087] As a possible implementation method, the voltage change data can be subjected to second-order differential processing to obtain the differential processing result corresponding to the voltage change data. Since if there is no lithium deposition in the battery to be tested, there is no fluctuation in the voltage change data that changes with time, and its second-order differentials are all greater than or equal to zero or are all less than or equal to zero. On the contrary, if there is lithium deposition in the battery to be tested, the voltage change data will fluctuate, and at this time there may be data points with second-order differentials greater than zero and data points with second-order differentials less than zero in the voltage change data. Therefore, after obtaining the voltage change data of the battery to be tested, the voltage change data can be subjected to second-order differential processing to obtain the differential processing result corresponding to the voltage change data. If the differential processing result is that each data point of the voltage change data is greater than or equal to zero or is less than or equal to zero, it means that there is no fluctuation in the voltage change data, and at this time, it can be determined that the lithium deposition detection result of the battery to be tested is that there is no lithium deposition phenomenon; on the contrary, it can be determined that the lithium deposition detection result of the battery to be tested is that there is lithium deposition phenomenon in the battery to be tested.

[0088] As another possible implementation, the voltage change data can be subjected to a third-order differential process to obtain a differential processing result corresponding to the voltage change data. Specifically, the voltage change data is first subjected to a first-order differential process to obtain a voltage differential curve, and then the voltage differential curve is subjected to a second-order differential process to obtain a differential processing result corresponding to the voltage change data. Since if the battery to be tested does not have a lithium deposition phenomenon, the voltage change data that changes with time does not fluctuate, and the voltage differential curve obtained after the first-order differential process does not fluctuate, which is manifested as the voltage differential curve does not have an inflection point, and the second-order differentials of each data point in the voltage differential curve are greater than or equal to zero or less than or equal to zero. On the contrary, if the battery to be tested has a lithium deposition phenomenon, the voltage differential curve will fluctuate, and at this time, the voltage differential curve has multiple data points that are inflection points, and accordingly, there may be data points with a second-order differential greater than zero and data points with a second-order differential less than zero in the voltage differential curve. Therefore, after obtaining the voltage change data of the battery to be tested, the voltage change data can be subjected to a third-order differential process to obtain a differential processing result corresponding to the voltage change data. If the differential processing result is that all data points of the voltage change data are greater than or equal to zero or less than or equal to zero, it means that there is no fluctuation in the voltage change data. At this time, it can be determined that there is no lithium deposition phenomenon in the battery to be tested; otherwise, it can be determined that the lithium deposition test result of the battery to be tested is that there is lithium deposition phenomenon in the battery to be tested.

[0089] After determining whether the battery to be tested has lithium deposition, if there is no lithium deposition, the detection of the amount of lithium deposition of the battery to be tested can be stopped. If there is lithium deposition, the irreversible lithium deposition amount of the battery to be tested at the target time point is obtained based on the target time point corresponding to the characteristic peak in the voltage differential curve and the capacity difference between the charging capacity corresponding to the current charging of the battery to be tested and the initial charging capacity of the battery to be tested.

[0090] In this way, by performing high-order differential processing on the voltage change data, it is possible to quickly determine whether the voltage change data has voltage fluctuations caused by lithium deposition, thereby being able to effectively determine whether the battery to be tested has lithium deposition. When it is determined that the battery to be tested has lithium deposition, the voltage differential curve can be used to detect the amount of irreversible lithium deposition in the battery to be tested, thereby improving the detection efficiency of the irreversible lithium deposition amount of the battery to be tested.

[0091] When the lithium deposition detection result of the battery to be tested is determined to be the presence of lithium deposition, the target time point corresponding to the characteristic peak in the voltage differential curve can be determined according to the voltage differential curve obtained after the voltage change data is subjected to the first-order differential processing, so as to obtain the irreversible lithium deposition amount of the battery to be tested at the target time point according to the time point and the capacity difference between the charging capacity corresponding to the current charging of the battery to be tested and the initial charging capacity of the battery to be tested. To further improve the accuracy of the lithium deposition amount detection, in some embodiments, according to the target time point corresponding to the characteristic peak in the voltage differential curve and the capacity difference between the charging capacity corresponding to the current charging of the battery to be tested and the initial charging capacity of the battery to be tested, the irreversible lithium deposition amount characterizing the battery to be tested at the target time point is obtained, including: performing high-order differential processing on the voltage differential curve to determine each inflection point in the voltage differential curve; determining the characteristic peak in the voltage differential curve according to the differential value corresponding to each inflection point in the voltage differential curve; obtaining the irreversible lithium deposition amount characterizing the battery to be tested at the target time point according to the target time point corresponding to the characteristic peak in the voltage differential curve and the capacity difference.

[0092] In some embodiments, in order to accurately determine the time point corresponding to the characteristic peak in the voltage differential curve, the voltage differential curve may be first subjected to second-order differential processing, and after obtaining the second-order derivative of each data point in the voltage differential curve, the second-order derivative of each data point may be detected. If the second-order differential processing result of the data point is zero, and the second-order derivatives of the data points on both sides of the data point are of different signs, such as the second-order derivative of the data point adjacent to the left of the data point is greater than zero, and the second-order derivative of the data point adjacent to the left of the data point is less than zero, then the data point may be determined to be an inflection point in the voltage differential curve.

[0093] After obtaining each inflection point, the differential value corresponding to each inflection point in the voltage differential curve, that is, the dV / dt value, can be obtained for comparison, so as to determine the inflection point with the smallest corresponding differential value as the characteristic peak of the voltage differential curve.

[0094] After determining the characteristic peak of the voltage differential curve, the irreversible lithium deposition amount of the battery to be tested at the target time point can be obtained based on the target time point corresponding to the characteristic peak in the voltage differential curve, the charging capacity corresponding to the current charging of the battery to be tested, and the initial charging capacity of the battery to be tested.

[0095] In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution in the present application will be described clearly and completely below. In some embodiments, Figure 5 As shown, the lithium plating detection method of the battery includes:

[0096] S201, according to the battery type of the battery to be tested, determine the initial cycle number corresponding to the battery type, wherein the initial cycle number is the number of charge and discharge cycles of the battery to be tested using a charge rate greater than a preset rate.

[0097] S202, according to the battery sample of the same battery type as the battery to be tested, the irreversible lithium capacity measured when the battery sample is charged at a preset rate after the initial number of cycles is separated, and the comparison result with the preset lithium capacity, the initial number of cycles is adjusted to obtain the preset number of cycles. Wherein, if it is determined that the irreversible lithium capacity measured when the battery sample is charged at a preset rate after the initial number of cycles is separated, is greater than the preset lithium capacity, the initial number of cycles is reduced; or, if it is determined that the irreversible lithium capacity measured when the battery sample is charged at a preset rate after the initial number of cycles is separated, is less than the preset lithium capacity, the initial number of cycles is increased.

[0098] S203, controlling the battery to be tested to charge at a preset rate every preset number of cycles.

[0099] S204, updating the preset number of cycles according to the number of times the battery to be tested is charged at the preset rate, and returning to S203, wherein the number of times of charging is negatively correlated with the preset number of cycles.

[0100] S205, obtaining voltage variation data of the battery to be tested that varies with time during a static period after the battery is charged at a preset rate.

[0101] S206, performing differential processing on the voltage change data to obtain a differential processing result corresponding to the voltage change data, so as to obtain a lithium deposition detection result of the battery to be tested according to the differential processing result. The differential processing includes first-order differential processing or high-order differential processing, and the high-order differential processing includes second-order differential processing or third-order differential processing.

[0102] S207, determining whether the lithium deposition test result of the battery to be tested contains lithium deposition, if so, executing S208, otherwise, ending the test.

[0103] S208, performing high-order differential processing on the current change curve obtained by performing first-order differential processing on the current change data, and determining each inflection point in the voltage differential curve.

[0104] S209, determining a characteristic peak in the voltage differential curve according to the differential value corresponding to each inflection point in the voltage differential curve.

[0105] S210, obtaining the irreversible lithium deposition amount representing the battery under test at the target time point according to the target time point corresponding to the characteristic peak in the voltage differential curve and the capacity difference between the charging capacity corresponding to the current charging of the battery under test and the initial charging capacity of the battery under test.

[0106] Figure 6 The present application provides a schematic diagram of the structure of a battery lithium deposition detection device. It should be understood that the device is Figure 1 and 5 The method embodiment executed in corresponds to the method embodiment, and the steps involved in the aforementioned method can be executed. The specific functions of the device can be referred to the description above. To avoid repetition, detailed description is appropriately omitted here. The device includes at least one software function module that can be stored in a memory in the form of software or firmware or solidified in the operating system (OS) of the device. Specifically, the device includes: a voltage data acquisition module 300, which is used to obtain the voltage change data of the battery to be tested during the static period after the battery to be tested is charged at a preset rate, which changes with time; a voltage data processing module 301, which is used to perform first-order differential processing on the voltage change data to obtain the voltage differential curve of the battery to be tested; a battery lithium deposition detection module 302, which is used to obtain the irreversible lithium deposition amount of the battery to be tested at the target time point according to the target time point corresponding to the characteristic peak in the voltage differential curve, and the capacity difference between the charging capacity corresponding to the current charging of the battery to be tested and the initial charging capacity of the battery to be tested.

[0107] In the technical scheme of the embodiment of the present application, by obtaining the voltage change data of the battery to be tested during the static period after the current charging is completed at a preset rate, the voltage change data is subjected to first-order differential processing to obtain the voltage differential curve of the battery to be tested, and according to the target time point corresponding to the characteristic peak in the voltage differential curve, and the capacity difference between the charging capacity corresponding to the current charging of the battery to be tested and the initial charging capacity of the battery to be tested, the irreversible lithium precipitation amount of the battery to be tested at the target time point is obtained. Since the voltage of the battery to be tested has the highest voltage value at the end of charging, with the beginning of static, the movement speed of the lithium ions in the battery to be tested will gradually decrease, and then the voltage of the battery will slowly decrease. If the battery to be tested has lithium precipitation, part of the lithium crystals precipitated on the surface of the anode will be re-embedded into the anode, delaying the decline in voltage, and the corresponding first-order differential curve will have a characteristic peak at this time, and the target time point corresponding to the characteristic peak can represent the time point when the lithium crystal ends the back embedding, so the irreversible lithium precipitation amount of the battery to be tested at the target time point can be determined by using the charging capacity corresponding to the current charging of the battery to be tested and the capacity difference between the initial charging capacity of the battery to be tested. This enables quantitative analysis of the degree of lithium plating in the battery, and thus accurately determines the risk of battery use.

[0108] According to some embodiments of the present application, the voltage data acquisition module 300 is also used to: control the battery to be tested to be charged at the preset rate every preset number of cycles; wherein the preset number of cycles includes the number of charge and discharge cycles in which the battery to be tested is charged and discharged at a charging rate greater than the preset rate.

[0109] According to some embodiments of the present application, the voltage data acquisition module 300 is further used to: determine the initial number of cycles corresponding to the battery type according to the battery type of the battery to be tested; and adjust the initial number of cycles to obtain the preset number of cycles by comparing the irreversible lithium capacity measured when charging is completed at the preset rate at intervals of the initial number of cycles with the battery sample having the same battery type as the battery to be tested and the preset lithium capacity;

[0110] Among them, it is determined that the irreversible lithium capacity of the battery sample measured when charging is completed at the preset rate after an interval of the initial number of cycles is greater than the preset lithium capacity, and the initial number of cycles is reduced; or it is determined that the irreversible lithium capacity of the battery sample measured when charging is completed at the preset rate after an interval of the initial number of cycles is less than the preset lithium capacity, and the initial number of cycles is increased.

[0111] According to some embodiments of the present application, the voltage data acquisition module 300 is further used to: update the preset number of cycles according to the number of times the battery under test is charged using the preset rate; wherein the number of times of charging is negatively correlated with the preset number of cycles.

[0112] According to some embodiments of the present application, the battery lithium deposition detection module 302 is specifically used to: when it is determined that lithium deposition exists in the battery to be tested according to the voltage change data, obtain the amount of irreversible lithium deposition that characterizes the battery to be tested at the target time point according to the target time point corresponding to the characteristic peak in the voltage differential curve and the capacity difference.

[0113] According to some embodiments of the present application, the battery lithium deposition detection module 302 is specifically used to: when it is determined that lithium deposition exists in the battery to be tested according to the voltage differential curve, obtain the amount of irreversible lithium deposition that characterizes the battery to be tested at the target time point according to the target time point corresponding to the characteristic peak in the voltage differential curve and the capacity difference.

[0114] According to some embodiments of the present application, the battery lithium deposition detection module 302 is specifically used to: perform high-order differential processing on the voltage change data to obtain a differential processing result corresponding to the voltage change data; when it is determined that lithium deposition exists in the battery to be tested according to the differential processing result, obtain the amount of irreversible lithium deposition that characterizes the battery to be tested at the target time point according to the target time point corresponding to the characteristic peak in the voltage differential curve and the capacity difference.

[0115] According to some embodiments of the present application, the battery lithium deposition detection module 302 is specifically used to: perform high-order differential processing on the voltage differential curve to determine each inflection point in the voltage differential curve; determine a characteristic peak in the voltage differential curve according to the differential value corresponding to each inflection point in the voltage differential curve; and obtain the amount of irreversible lithium deposition that characterizes the battery to be tested at the target time point according to the target time point corresponding to the characteristic peak in the voltage differential curve and the capacity difference.

[0116] According to some embodiments of the present application, Figure 7 As shown, the present application provides an electronic device 400, including: a processor 401 and a memory 402, the processor 401 and the memory 402 are interconnected and communicate with each other through a communication bus 403 and / or other forms of connection mechanisms (not marked), the memory 402 stores a computer program executable by the processor 401, and when the computing device is running, the processor 401 executes the computer program to execute a method executed by an external terminal in any optional implementation method, for example: obtaining voltage change data that changes with time during a static period after the battery to be tested is charged at a preset rate; performing first-order differential processing on the voltage change data to obtain a voltage differential curve of the battery to be tested; according to the target time point corresponding to the characteristic peak in the voltage differential curve, and the capacity difference between the charging capacity corresponding to the current charging of the battery to be tested and the initial charging capacity of the battery to be tested, obtaining the irreversible lithium deposition amount characterizing the battery to be tested at the target time point.

[0117] The present application provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the method in any of the aforementioned optional implementations is executed.

[0118] Among them, the storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable red-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk or optical disk.

[0119] The present application provides a computer program product. When the computer program product is run on a computer, the computer is enabled to execute the method in any optional implementation manner.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A method for detecting lithium deposition in a battery, characterized in that: The method comprises: Obtaining voltage change data of the battery under test that changes with time during a static period after the battery is charged at a preset rate; Performing first-order differential processing on the voltage change data to obtain a voltage differential curve of the battery to be tested; According to the characteristic peak in the voltage differential curve, a target time point corresponding to the characteristic peak is determined, so as to obtain the irreversible lithium deposition amount of the battery to be tested at the target time point according to the target time point and the capacity difference between the charging capacity corresponding to the current charging of the battery to be tested and the initial charging capacity of the battery to be tested; Wherein, the irreversible lithium deposition amount is the capacity difference.

2. The method according to claim 1, characterized in that The method further comprises: Controlling the battery to be tested to be charged at the preset rate every preset number of cycles; The preset number of cycles includes the number of charge and discharge cycles of the battery to be tested using a charge rate greater than the preset rate.

3. The method according to claim 2, characterized in that The method further comprises: According to the battery type of the battery to be tested, determining the initial number of cycles corresponding to the battery type; According to a battery sample of the same battery type as the battery to be tested, the irreversible lithium capacity measured when charging is completed at the preset rate at intervals of the initial number of cycles, and the comparison result with the preset lithium capacity, the initial number of cycles is adjusted to obtain the preset number of cycles; Among them, it is determined that the irreversible lithium capacity of the battery sample measured when charging is completed at the preset rate after an interval of the initial number of cycles is greater than the preset lithium capacity, and the initial number of cycles is reduced; or it is determined that the irreversible lithium capacity of the battery sample measured when charging is completed at the preset rate after an interval of the initial number of cycles is less than the preset lithium capacity, and the initial number of cycles is increased.

4. The method according to claim 2, characterized in that: The method further comprises: According to the number of times the battery to be tested is charged using the preset rate, updating the preset number of cycles; The charging times are negatively correlated with the preset number of cycles.

5. The method according to claim 1, characterized in that According to the characteristic peak in the voltage differential curve, a target time point corresponding to the characteristic peak is determined, so as to obtain the irreversible lithium deposition amount of the battery to be tested at the target time point according to the target time point and the capacity difference between the charging capacity corresponding to the current charging of the battery to be tested and the initial charging capacity of the battery to be tested, including: When it is determined that lithium deposition occurs in the battery under test according to the voltage variation data, the irreversible lithium deposition amount of the battery under test at the target time point is obtained according to the target time point corresponding to the characteristic peak in the voltage differential curve and the capacity difference.

6. The method according to claim 1, characterized in that According to the characteristic peak in the voltage differential curve, a target time point corresponding to the characteristic peak is determined, so as to obtain the irreversible lithium deposition amount of the battery to be tested at the target time point according to the target time point and the capacity difference between the charging capacity corresponding to the current charging of the battery to be tested and the initial charging capacity of the battery to be tested, including: When it is determined that the battery to be tested has lithium deposition according to the voltage differential curve, the irreversible lithium deposition amount of the battery to be tested at the target time point is obtained according to the target time point corresponding to the characteristic peak in the voltage differential curve and the capacity difference.

7. The method according to claim 1, characterized in that According to the characteristic peak in the voltage differential curve, a target time point corresponding to the characteristic peak is determined, so as to obtain the irreversible lithium deposition amount of the battery to be tested at the target time point according to the target time point and the capacity difference between the charging capacity corresponding to the current charging of the battery to be tested and the initial charging capacity of the battery to be tested, including: Performing high-order differential processing on the voltage change data to obtain a differential processing result corresponding to the voltage change data; When it is determined that lithium deposition occurs in the battery under test according to the differential processing result, the irreversible lithium deposition amount of the battery under test at the target time point is obtained according to the target time point corresponding to the characteristic peak in the voltage differential curve and the capacity difference.

8. The method according to any one of claims 1 to 7, characterized in that: According to the characteristic peak in the voltage differential curve, a target time point corresponding to the characteristic peak is determined, so as to obtain the irreversible lithium deposition amount of the battery to be tested at the target time point according to the target time point and the capacity difference between the charging capacity corresponding to the current charging of the battery to be tested and the initial charging capacity of the battery to be tested, including: Performing high-order differential processing on the voltage differential curve to determine each inflection point in the voltage differential curve; Determining a characteristic peak in the voltage differential curve according to a differential value corresponding to each inflection point in the voltage differential curve; According to the target time point corresponding to the characteristic peak in the voltage differential curve and the capacity difference, the irreversible lithium deposition amount of the battery to be tested at the target time point is obtained.

9. A battery lithium deposition detection device, characterized in that: The device comprises: A voltage data acquisition module is used to obtain voltage change data of the battery under test that changes with time during a static period after the battery is charged at a preset rate. A voltage data processing module, used for performing first-order differential processing on the voltage change data to obtain a voltage differential curve of the battery to be tested; A battery lithium deposition detection module is used to determine a target time point corresponding to the characteristic peak in the voltage differential curve, so as to obtain an irreversible lithium deposition amount characterizing the battery under test at the target time point according to the target time point and the capacity difference between the charging capacity corresponding to the current charging of the battery under test and the initial charging capacity of the battery under test; Wherein, the irreversible lithium deposition amount is the capacity difference.

10. An electronic device comprising a processor and a memory storing a computer program, characterized in that: When the processor executes the computer program, the method according to any one of claims 1 to 8 is implemented.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 8 is implemented.

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