A method and device for detecting lithium plating in a lithium battery

Abstract

The present invention provides a method and a device for detecting lithium plating of a lithium battery. The method includes: determining a target SOC corresponding to lithium plating of a battery cell to be tested; determining a target charge amount to be charged into the battery cell to be tested according to the target SOC; adjusting the state of the battery cell to be tested to an initial state based on the target charge amount; detecting the battery cell to be tested in the initial state based on a detection strategy, where the detection strategy is determined based on the target SOC. Thus, since lithium plating of the battery mainly occurs in the high SOC region, the present application first determines the target SOC corresponding to lithium plating of the battery cell to be tested. In this way, when detecting lithium plating in the range from the target SOC region to 100% SOC, the influence of the self-temperature rise of the battery cell on the detection can be reduced, and the lithium plating phenomenon of the battery cell can be detected more accurately.

Description

Technical Field

[0001] This application relates to the technical field of battery detection, and particularly to a method and device for detecting lithium plating in a lithium battery. Background Art

[0002] Due to advantages such as high energy, long life, and low pollution, lithium-ion batteries have become the mainstream power supply system for new energy electric vehicles.

[0003] During the charging process of a battery, lithium ions are deintercalated from the positive electrode and intercalated into the negative electrode. If the lithium ions cannot be normally intercalated into the negative electrode, they will combine with the electrons shuttling from the negative electrode and deposit on the surface of the negative electrode, that is, lithium plating occurs. Lithium plating will cause irreversible loss of lithium ions and affect the life of the lithium battery. In addition, lithium dendrites formed by lithium plating on the uneven surface of the negative electrode may pierce the separator, causing the lithium battery to catch fire and explode.

[0004] Therefore, before the lithium battery is put into use, how to effectively determine whether there is lithium plating in the lithium battery and then optimize the cell design process is an urgent problem to be solved. Summary of the Invention

[0005] In view of the problems existing in the prior art, embodiments of the present invention provide a method and device for detecting lithium plating in a lithium battery, which are used to solve the technical problems that in the prior art, it is impossible to effectively detect whether there is lithium plating in the battery, and thus it is impossible to accurately analyze the cause of lithium plating in the battery, resulting in the inability to effectively improve the cell design process.

[0006] In the first aspect of the present invention, a method for detecting lithium plating in a lithium battery is provided. The method includes:

[0007] Determine the target state of charge (SOC) corresponding to when the lithium plating occurs in the battery under test;

[0008] Determine the target charge amount to be charged into the battery under test according to the target SOC;

[0009] Based on the target charge amount, adjust the state of the battery under test to the initial state;

[0010] Detect the battery under test in the initial state based on a detection strategy, and the detection strategy is determined based on the target SOC.

[0011] In the above solution, the determination of the target SOC corresponding to when the lithium plating occurs in the battery under test includes:

[0012] When charging the battery under test to the full charge state at a preset battery under test rate, collect the temperature and the corresponding SOC of the battery under test at a preset collection period;

[0013] Determine the T-SOC curve based on the temperature and the corresponding SOC of the battery cell to be tested; T is the temperature;

[0014] Perform piecewise fitting on the T-SOC curve to obtain multiple T-SOC straight lines;

[0015] Take the maximum SOC corresponding to the T-SOC straight line with the largest slope as the target SOC.

[0016] In the above solution, before charging the battery cell to be tested at a preset battery cell rate until it is fully charged, the method further includes:

[0017] After discharging the battery cell to be tested at room temperature, place the battery cell to be tested in a preset test temperature until the internal temperature of the battery cell to be tested is consistent with the test temperature.

[0018] In the above solution, determining the target charge amount to be charged into the battery cell to be tested according to the target SOC includes:

[0019] Determine the product value between the target SOC and the rated capacity of the battery cell to be tested, and the product value is the target charge amount.

[0020] In the above solution, adjusting the state of the battery cell to be tested to the initial state based on the target charge amount includes:

[0021] Discharge the battery cell to be tested at room temperature, and after standing for a preset period of time, charge the battery cell to be tested with the target charge amount at the battery cell rate to be tested;

[0022] Place the battery cell to be tested charged with the target charge amount in a preset test temperature until the internal temperature of the battery cell to be tested is consistent with the test temperature.

[0023] In the above solution, detecting the battery cell to be tested in the initial state based on the detection strategy includes:

[0024] Based on a preset number of cyclic detections, charge the battery cell to be tested at the battery cell rate to be tested until the charge cut-off condition is reached;

[0025] After the battery cell to be tested stands for a preset period of time, discharge the battery cell to be tested until the charge amount of the battery cell to be tested reaches the target charge amount, and then stand for a preset period of time;

[0026] After the cycle is completed, charge the battery cell to be tested at room temperature until it is fully charged;

[0027] Analyze the battery cell to be tested to obtain the negative electrode interface image of the battery cell to be tested;

[0028] It is determined that lithium plating exists in the battery cell to be tested according to the negative electrode interface image.

[0029] In the above solution, determining that lithium plating exists in the battery cell to be tested according to the negative electrode interface image includes:

[0030] If it is determined that there is grayish-white metal in the negative electrode interface, it is determined that lithium plating exists in the battery cell to be tested.

[0031] In the second aspect of the present invention, a device for detecting lithium plating in a lithium battery is provided. The device includes:

[0032] A determination unit, configured to determine the target SOC corresponding to lithium plating in the battery cell to be tested; determine the target charge amount to be charged into the battery cell to be tested according to the target SOC;

[0033] An adjustment unit, configured to adjust the state of the battery cell to be tested to the initial state based on the target charge amount;

[0034] A detection unit, configured to detect the battery cell to be tested in the initial state based on a detection strategy, where the detection strategy is determined based on the target SOC.

[0035] In the above solution, the determination unit is specifically configured to:

[0036] When charging the battery cell to be tested to the full charge state at a preset battery cell rate, collect the temperature and the corresponding SOC of the battery cell to be tested at a preset collection period;

[0037] Determine the T-SOC curve based on the temperature and the corresponding SOC of the battery cell to be tested; T is the temperature;

[0038] Perform piecewise fitting on the T-SOC curve to obtain multiple T-SOC straight lines;

[0039] Use the maximum SOC corresponding to the T-SOC straight line with the largest slope as the target SOC.

[0040] In the above solution, the adjustment unit is configured to:

[0041] After discharging the battery cell to be tested to zero at room temperature, place the battery cell to be tested in a preset test temperature until the internal temperature of the battery cell to be tested is consistent with the test temperature.

[0042] In the above solution, the determination unit is specifically configured to:

[0043] Determine the product value of the target SOC and the rated capacity of the battery cell to be tested, and the product value is the target charge amount.

[0044] In the above solution, the determination unit is specifically configured to:

[0045] Determine the product value between the target SOC and the rated capacity of the battery cell under test, and the product value is the target power.

[0046] In the above solution, the adjustment unit is specifically used for:

[0047] Discharge the battery cell under test at room temperature, and after standing for a preset period of time, charge the target power into the battery cell under test at the rate of the battery cell under test.

[0048] Place the battery cell under test charged with the target power in a preset test temperature until the internal temperature of the battery cell under test is consistent with the test temperature.

[0049] In the above solution, the detection unit is specifically used for:

[0050] Based on a preset number of cyclic detections, charge the battery cell under test at the rate of the battery cell under test until the charging cut-off condition is reached.

[0051] After the battery cell under test stands for a preset period of time, discharge the battery cell under test until the power of the battery cell under test reaches the target power, and then stand for a preset period of time.

[0052] After the cycle is completed, charge the battery cell under test at room temperature until it is fully charged.

[0053] Analyze the battery cell under test to obtain the negative electrode interface image of the battery cell under test.

[0054] Determine that the battery cell under test has lithium plating according to the negative electrode interface image.

[0055] In the above solution, the detection unit is specifically used for:

[0056] If it is determined that there is grayish-white metal in the negative electrode interface, it is determined that the battery cell under test has lithium plating.

[0057] The present invention provides a method and device for detecting lithium plating of a lithium battery. The method includes: determining a target SOC corresponding to lithium plating of a battery cell under test; determining a target power to be charged into the battery cell under test according to the target SOC; adjusting the state of the battery cell under test to an initial state based on the target power; detecting the battery cell under test in the initial state based on a detection strategy, and the detection strategy is determined based on the target SOC. Thus, since battery lithium plating mainly occurs in the high SOC region, the present application first determines the target SOC corresponding to lithium plating of the battery cell under test. In this way, when detecting lithium plating in the range of the target SOC region to 100% SOC, the influence of the self-temperature rise of the battery cell on the detection can be reduced, and the lithium plating phenomenon of the battery cell can be detected more accurately. Description of the Drawings

[0058] Upon reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention. Moreover, throughout the drawings, the same reference numerals are used to represent the same components.

[0059] In the drawings:

[0060] Figure 1 A schematic flow chart of a method for detecting lithium plating in a battery according to an embodiment of the present invention is shown;

[0061] Figure 2 A schematic structural diagram of a device for detecting lithium plating in a battery according to an embodiment of the present invention is shown. Detailed Embodiments

[0062] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be fully conveyed to those skilled in the art.

[0063] An embodiment of the present invention provides a method for detecting lithium plating in a lithium battery, as Figure 1 shown, the method mainly includes the following steps:

[0064] Step S110, determining the target SOC corresponding to the lithium plating of the battery cell to be tested.

[0065] In this embodiment, the environment of -20 to 15 °C is called a low-temperature environment. If lithium plating occurs in the battery in a low-temperature environment, it generally occurs in the high-SOC region of the battery. In order to accurately and quickly detect whether lithium plating occurs in the battery cell to be tested, it is necessary to determine the target SOC corresponding to the lithium plating of the battery cell to be tested. Then, subsequent lithium plating detection can be performed on the battery cell to be tested in the range of the target SOC to 100% SOC.

[0066] In one embodiment, determining the target SOC corresponding to the lithium plating of the battery cell to be tested includes:

[0067] Charging the battery cell to be tested to a full charge state at a preset battery cell rate of the battery to be tested, and collecting the temperature and the corresponding SOC of the battery cell to be tested at a preset acquisition period.

[0068] Determining a T-SOC curve based on the temperature and the corresponding SOC of the battery cell to be tested; T is the temperature.

[0069] Segmentally fitting the T-SOC curve to obtain a plurality of T-SOC straight lines.

[0070] Take the maximum SOC corresponding to the T-SOC line with the maximum slope as the target SOC.

[0071] In one embodiment, before charging the battery cell to be tested at a preset battery rate until it reaches a fully charged state, the method further includes:

[0072] After discharging the battery cell to be tested at room temperature, place the battery cell to be tested in a preset test temperature until the internal temperature of the battery cell to be tested is consistent with the test temperature.

[0073] Specifically, room temperature generally refers to 25°C. Discharge the battery cell to be tested at 25°C, and then place the battery cell to be tested in a test environment with a test temperature of -20 to 15°C until the internal temperature of the battery cell to be tested is consistent with the test temperature.

[0074] It should be noted that the test temperature can take multiple different temperature values. To improve the accuracy of detection, detection can be performed based on each test temperature.

[0075] Then, charge the battery cell to be tested at the battery rate to be tested until it reaches 100% SOC. During the charging process of the battery cell to be tested, collect the temperature and the corresponding SOC of the battery cell to be tested at a preset collection period (such as every 1 s). A T-SOC curve can be drawn based on the temperature and the corresponding SOC of the battery cell to be tested. In the T-SOC curve, use the least squares method to segment and fit the T-SOC curve to obtain multiple T-SOC lines. The slope of each line is different. Take the maximum SOC corresponding to the T-SOC line with the maximum slope as the target SOC.

[0076] The target SOC determined in this way can reflect the lithium plating phenomenon to the greatest extent, so as to improve the accuracy of subsequent detection.

[0077] Step S111, determine the target charge amount to be charged into the battery cell to be tested according to the target SOC.

[0078] After the target SOC is determined, the target charge amount to be charged into the battery cell to be tested can be determined according to the target SOC. Specifically, it includes:

[0079] Determine the product value between the target SOC and the rated capacity of the battery cell to be tested, and the product value is the target charge amount.

[0080] That is, the target charge amount C2 can be determined by the formula C2 = C1 * X%. Where C1 is the rated capacity and X% is the target SOC.

[0081] Step S112, adjust the state of the battery cell to be tested to the initial state based on the target charge amount.

[0082] After the target power is determined, the power of the battery cell to be tested is discharged at room temperature. After standing for a preset period, the target power is charged into the battery cell to be tested at the rate of the battery cell to be tested. The preset period can be 1 h or determined based on the actual detection situation, and no limitation is made here.

[0083] Place the battery cell to be tested charged with the target power in a preset test temperature until the internal temperature of the battery cell to be tested is consistent with the test temperature.

[0084] In this way, the state of the battery cell to be tested is adjusted to the initial state, preparing for subsequent detection.

[0085] Step S113: Detect the battery cell to be tested in the initial state based on a detection strategy, where the detection strategy is determined based on the target SOC.

[0086] In one implementation, detecting the battery cell to be tested in the initial state based on a detection strategy includes:

[0087] Based on a preset number of cyclic detections, charge the battery cell to be tested at the rate of the battery cell to be tested until the charging cut-off condition is reached.

[0088] After the battery cell to be tested stands for a preset period, discharge the battery cell to be tested until the power of the battery cell to be tested reaches the target power.

[0089] After the cycle is completed, charge the battery cell to be tested at room temperature until it is fully charged.

[0090] Analyze the battery cell to be tested to obtain the negative electrode interface image of the battery cell to be tested.

[0091] Determine that lithium plating exists in the battery cell to be tested according to the negative electrode interface image.

[0092] In one implementation, the determining that lithium plating exists in the battery cell to be tested according to the negative electrode interface image includes:

[0093] If it is determined that there is grayish-white metal in the negative electrode interface, it is determined that lithium plating exists in the battery cell to be tested. Among them, the negative electrode interface is a golden yellow interface.

[0094] Specifically, when detecting the battery cell to be tested, two steps need to be executed:

[0095] First, charge the battery cell to be tested at the rate of the battery cell to be tested until the charging cut-off condition is reached.

[0096] Second, after the battery cell to be tested stands for 1 h, discharge the battery cell to be tested until the power of the battery cell to be tested reaches the target power, and then stand for a preset period (such as 1 h).

[0097] Repeat the above two steps for a preset number of detection times (e.g., 10 times), and finally charge the battery cell to be tested to 100% SOC at room temperature.

[0098] When analyzing the battery cell to be tested, use a dissection device to cut open the battery cell to be tested to obtain an image of the negative electrode interface of the battery cell to be tested. Determine that lithium plating exists in the battery cell to be tested based on the image of the negative electrode interface.

[0099] In this embodiment, it is possible to determine whether lithium plating exists by observing the image of the negative electrode interface manually, or to analyze the image of the negative electrode interface through an image processing device to determine whether lithium plating exists.

[0100] When observing manually, since the negative electrode interface is golden yellow, if there is grayish-white metal (lithium is grayish-white) in the golden yellow interface, it is determined that lithium plating exists in the battery cell to be tested.

[0101] When analyzing the image of the negative electrode interface through an image processing device, the image of the negative electrode interface can be subjected to grayscale processing. Divide the grayscale-processed image of the negative electrode interface into blocks to obtain a plurality of blocks (the more the number of blocks, the better). Obtain the pixel average value of each pixel point in each block, and determine whether lithium plating exists based on the pixel average value.

[0102] Since the normal image of the negative electrode interface is golden yellow and there will be grayish-white during lithium plating, if the pixel average value of a block is inconsistent with the pixel average value of the normal image of the negative electrode interface, it indicates that lithium plating exists.

[0103] In this embodiment, after determining that lithium plating exists in the battery cell to be tested, the battery cell process can also be analyzed and improved based on the lithium plating characteristics. For example, if the lithium plating is overall interface lithium plating, it indicates that there is a problem with the battery cell design, and the NP ratio of the positive and negative electrodes of the battery cell is too low, and it can be adjusted subsequently. If local dot-like or block-like lithium plating appears, it indicates that there may be a problem with the battery cell process, which may be due to uneven coating of the positive and negative electrodes of the battery cell, wrinkles in the battery cell during assembly, or foreign matters such as dust mixed in during the production process.

[0104] Based on the same inventive concept as the foregoing embodiment, this embodiment also provides a device for detecting lithium plating in a lithium battery, as Figure 2 shown, the device includes:

[0105] A determination unit 21, configured to determine the target SOC corresponding to lithium plating in the battery cell to be tested; determine the target charge amount to be charged into the battery cell to be tested according to the target SOC;

[0106] An adjustment unit 22, configured to adjust the state of the battery cell to be tested to an initial state based on the target charge amount;

[0107] A detection unit 23, configured to detect the battery cell to be tested in the initial state based on a detection strategy, where the detection strategy is determined based on the target SOC.

[0108] In one embodiment, the determining unit 21 is specifically configured to:

[0109] When the battery cell to be tested is charged to a full-charge state at a preset battery rate, the temperature and corresponding SOC of the battery cell to be tested are collected at a preset collection period;

[0110] Determine a T-SOC curve based on the temperature of the battery cell to be tested and the corresponding SOC, wherein T is the temperature;

[0111] Performing segmented fitting on the T-SOC curve to obtain multiple T-SOC straight lines;

[0112] The maximum SOC corresponding to the T-SOC straight line with the largest slope is used as the target SOC.

[0113] The determining unit 21 is specifically configured to:

[0114] Determine a product value between the target SOC and the rated capacity of the battery cell to be tested, where the product value is the target power.

[0115] Since the device described in the embodiment of the present invention is a device used to implement the method for detecting lithium deposition in a lithium battery according to the embodiment of the present invention, those skilled in the art will be able to understand the specific structure and variations of the device based on the method described in the embodiment of the present invention, and therefore, no further description will be given here. All devices used in the method according to the embodiment of the present invention fall within the scope of protection of the present invention.

[0116] Through one or more embodiments of the present invention, the present invention has the following beneficial effects or advantages:

[0117] The present invention provides a method and device for detecting lithium deposition in a lithium battery, the method comprising: determining a target SOC corresponding to when a cell to be tested deposits lithium; determining a target amount of electricity to be charged into the cell to be tested based on the target SOC; adjusting the state of the cell to be tested to an initial state based on the target amount of electricity; detecting the cell to be tested in the initial state based on a detection strategy, wherein the detection strategy is determined based on the target SOC; thus, since lithium deposition in a battery mainly occurs in a high SOC region, the present application first determines a target SOC corresponding to when lithium deposition occurs in the cell to be tested, so that when lithium deposition detection is performed within a range from the target SOC region to 100% SOC, the influence of the cell's own temperature rise on the detection can be reduced, and the lithium deposition phenomenon of the cell can be detected more accurately; and the cell process can be targetedly optimized based on the lithium deposition characteristics, thereby further improving the quality of the cell.

[0118] The algorithms and displays provided herein are not inherently related to any particular computer, virtual system, or other apparatus. Various general-purpose systems may also be used in conjunction with the teachings based hereon. The structure required to construct such systems will be apparent from the above description. In addition, the present invention is not directed to any particular programming language. It should be appreciated that the present invention as described herein may be implemented using various programming languages, and the description of specific languages above is for the purpose of disclosing the best mode of the present invention.

[0119] In the specification provided herein, numerous specific details are set forth. However, it can be understood that embodiments of the present invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0120] Similarly, it should be understood that in order to streamline this disclosure and assist in understanding one or more of the various inventive aspects, in the above description of the exemplary embodiments of the present invention, various features of the present invention are sometimes grouped together in a single embodiment, figure, or description thereof. However, the disclosed method should not be construed as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected in the following claims, the inventive aspects lie in less than all the features of the single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of the present invention.

[0121] Those skilled in the art will appreciate that the modules in the devices in the embodiments can be adaptively changed and disposed in one or more devices different from the embodiments. The modules or units or components in the embodiments can be combined into one module or unit or component, and in addition, they can be divided into multiple sub-modules or sub-units or sub-components. Except that at least some of such features and / or processes or units are mutually exclusive, any combination can be used to combine all the features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all the processes or units of any method or device so disclosed. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) can be replaced by an alternative feature that provides the same, equivalent, or similar purpose.

[0122] In addition, those skilled in the art can understand that although some embodiments herein include certain features included in other embodiments rather than other features, the combination of features of different embodiments means that it is within the scope of the present invention and forms different embodiments. For example, in the following claims, any one of the claimed embodiments can be used in any combination.

[0123] Each component embodiment of the present invention can be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. Those skilled in the art should understand that a microprocessor or a digital signal processor (DSP) can be used in practice to implement some or all of the functions of some or all of the components of the gateway, proxy server, and system according to the embodiments of the present invention. The present invention can also be implemented as a device or apparatus program (such as a computer program and a computer program product) for executing part or all of the methods described herein. Such a program for implementing the present invention can be stored on a computer-readable medium, or can be in the form of one or more signals. Such signals can be downloaded from an Internet website, or provided on a carrier signal, or provided in any other form.

[0124] It should be noted that the above embodiments illustrate the present invention rather than limit the present invention, and those skilled in the art can design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The present invention can be implemented by means of hardware including several different elements and by means of a suitably programmed computer. In a unit claim listing several devices, several of these devices can be embodied by the same item of hardware. The use of the words first, second, and third, etc. does not denote any order. These words can be interpreted as names.

[0125] Although the preferred embodiments of the present application have been described, those skilled in the art can make additional changes and modifications once they learn the basic creative concept. Therefore, the appended claims are intended to be construed as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0126] The above is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for detecting lithium deposition in a lithium battery, characterized in that, The method includes: Determining a target SOC corresponding to lithium deposition in the battery cell under test; Determining a target charge amount to be charged into the battery cell under test according to the target SOC; Adjusting the state of the battery cell under test to an initial state based on the target charge amount; Detecting the battery cell under test in the initial state based on a detection strategy, where the detection strategy is determined based on the target SOC; wherein, detecting the battery cell under test is to perform lithium deposition detection within the range of the target SOC region to 100% SOC; The determining of the target SOC corresponding to lithium deposition in the battery cell under test includes: When charging the battery cell under test at a preset battery cell rate until it reaches a fully charged state, collecting the temperature and corresponding SOC of the battery cell under test at a preset collection period; Determining a T-SOC curve based on the temperature and corresponding SOC of the battery cell under test; T is the temperature; Segmentally fitting the T-SOC curve to obtain multiple T-SOC straight lines; Taking the maximum SOC corresponding to the T-SOC straight line with the largest slope as the target SOC.

2. The method according to claim 1, characterized in that, Before charging the battery cell under test at a preset battery cell rate until it reaches a fully charged state, the method further includes: After discharging the battery cell under test to zero at room temperature, placing the battery cell under test in a preset test temperature until the internal temperature of the battery cell under test is consistent with the test temperature.

3. The method according to claim 1, characterized in that, The determining of the target charge amount to be charged into the battery cell under test according to the target SOC includes: Determining the product value between the target SOC and the rated capacity of the battery cell under test, and the product value is the target charge amount.

4. The method according to claim 1, wherein The adjusting of the state of the battery cell under test to an initial state based on the target charge amount includes: Discharging the battery cell under test to zero at room temperature, standing for a preset period, and then charging the battery cell under test at the battery cell rate with the target charge amount; Placing the battery cell under test charged with the target charge amount in a preset test temperature until the internal temperature of the battery cell under test is consistent with the test temperature.

5. The method according to claim 1, characterized in that The detecting of the battery cell under test in the initial state based on the detection strategy includes: Based on a preset number of cyclic detections, charging the battery cell under test at the battery cell rate until a charging cut-off condition is reached; After standing the battery cell under test for a preset period, discharging the battery cell under test until the charge amount of the battery cell under test reaches the target charge amount, and then standing for a preset period; After the cycle is completed, charging the battery cell under test at room temperature until it reaches a fully charged state; Analyzing the battery cell under test to obtain an image of the negative electrode interface of the battery cell under test; Determining that lithium deposition exists in the battery cell under test according to the negative electrode interface image; 6. The method according to claim 5, characterized in that, The determining that lithium deposition exists in the battery cell under test according to the negative electrode interface image includes: If it is determined that there is grayish-white metal in the negative electrode interface, it is determined that lithium deposition exists in the battery cell under test.

7. A device for detecting lithium deposition in a lithium battery, characterized in that, The device includes: A determining unit, configured to determine a target SOC corresponding to lithium deposition in the battery cell under test; and determine a target charge amount to be charged into the battery cell under test according to the target SOC; An adjusting unit, configured to adjust the state of the battery cell under test to an initial state based on the target charge amount; The detection unit is used to detect the battery cell to be tested in the initial state based on a detection strategy, and the detection strategy is determined based on the target SOC; wherein, the detection of the battery cell to be tested is to perform lithium deposition detection within the range of the target SOC region to 100% SOC; The determination unit is specifically used for: When charging the battery cell to be tested to the full charge state at a preset battery cell rate of the battery to be tested, collecting the temperature and the corresponding SOC of the battery cell to be tested at a preset acquisition period; Determining a T-SOC curve based on the temperature and the corresponding SOC of the battery cell to be tested; T is the temperature; Performing piecewise fitting on the T-SOC curve to obtain a plurality of T-SOC straight lines; Taking the maximum SOC corresponding to the T-SOC straight line with the largest slope as the target SOC.

8. The device according to claim 7, characterized in that The determination unit is specifically used for: Determining the product value between the target SOC and the rated capacity of the battery cell to be tested, and the product value is the target power.

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