A method, device and medium for detecting negative electrode of lithium battery, and a detection system

Abstract

The embodiment of the present invention provides a method, device and medium for detecting the negative electrode of a lithium battery, and a detection system; the method comprises: obtaining at least one target sub-image collected for the negative electrode of a target lithium battery, each target sub-image comprising a lithium deposition area on the negative electrode of the target lithium battery; determining the target position to which each target sub-image belongs on the negative electrode of the target lithium battery; obtaining a weight preset for the target position, and determining the lithium deposition area of ​​the negative electrode of the target lithium battery according to the target sub-image and the corresponding weight; determining the lithium deposition situation of the negative electrode of the target lithium battery according to the lithium deposition area of ​​the negative electrode of the target lithium battery. Through the embodiment of the present invention, the lithium deposition situation of the negative electrode of the lithium battery is determined based on the difficulty of lithium deposition at different positions of the negative electrode of the lithium battery, thereby accurately measuring the lithium deposition situation of the entire negative electrode of the lithium battery.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium batteries, and in particular to a method, device and medium for detecting a negative electrode of a lithium battery, and a detection system. Background Art

[0002] In recent years, with the continuous development of lithium batteries, the application scenarios of lithium batteries are becoming more and more extensive; however, there are also many hidden dangers in the production and use of lithium batteries; for example: if lithium plating occurs during the production or use of lithium batteries, it may cause safety accidents of lithium batteries.

[0003] Therefore, how to accurately detect the lithium deposition of lithium batteries has become a technical problem that urgently needs to be solved. Summary of the invention

[0004] In view of the above problems, a method, device and medium for detecting a negative electrode of a lithium battery are proposed to overcome the above problems or at least partially solve the above problems, and a detection system is provided, comprising:

[0005] A method for detecting a negative electrode of a lithium battery, the method comprising:

[0006] Acquire at least one target sub-image collected for the negative electrode of the target lithium battery, each target sub-image including a lithium deposition area on the negative electrode of the target lithium battery;

[0007] Determine the target position of each target sub-image on the negative electrode of the target lithium battery;

[0008] Obtaining a preset weight for the target position, and determining the lithium deposition area of ​​the negative electrode of the target lithium battery according to the target sub-image and the corresponding weight;

[0009] According to the lithium deposition area of ​​the negative electrode of the target lithium battery, the lithium deposition situation of the negative electrode of the target lithium battery is determined.

[0010] Optionally, acquiring at least one target sub-image collected for the negative electrode of a target lithium battery includes:

[0011] Acquire a first target image including a negative electrode of a target lithium battery;

[0012] Extracting a second target image from the first target image according to a preset lithium deposition grayscale threshold;

[0013] According to the target division method preset for the target lithium battery negative electrode, the second target image is divided to obtain at least one target sub-image.

[0014] Optionally, the second target image is divided according to a target division method preset for the target lithium battery negative electrode to obtain at least one target sub-image, including:

[0015] Dividing the first target image according to the target division method to obtain at least one third target image;

[0016] At least one target sub-image is determined according to the intersection of the second target image and at least one third target image.

[0017] Optionally, extracting the second target image from the first target image according to a preset lithium deposition grayscale threshold comprises:

[0018] Determine the grayscale value of each pixel in the first target image, and determine at least one target pixel whose grayscale value is not less than a preset lithium deposition grayscale threshold;

[0019] A second target image is generated according to at least one target pixel point.

[0020] Optionally, determining the lithium deposition area of ​​the negative electrode of the target lithium battery according to the target sub-image and the corresponding weight includes:

[0021] Determine the area of ​​a target sub-image;

[0022] Determine the lithium deposition area of ​​a target sub-image according to the area of ​​the target sub-image and the weight corresponding to the target sub-image;

[0023] According to the lithium deposition areas of all target sub-images, the lithium deposition area of ​​the negative electrode of the target lithium battery is determined.

[0024] Optionally, determining the lithium deposition situation of the negative electrode of the target lithium battery according to the lithium deposition area of ​​the negative electrode of the target lithium battery includes:

[0025] Obtain the total area of ​​the negative electrode of the target lithium battery;

[0026] The lithium deposition situation of the negative electrode of the target lithium battery is determined according to the ratio of the lithium deposition area of ​​the negative electrode of the target lithium battery to the total area of ​​the negative electrode of the target lithium battery.

[0027] Optionally, the method further comprises:

[0028] Obtain target abnormal parameters corresponding to lithium batteries;

[0029] Establish the lithium plating situation of the target lithium battery negative electrode and the corresponding relationship with the target abnormal parameters.

[0030] The embodiment of the present invention further provides a detection system, in which the above-mentioned detection method for the negative electrode of a lithium battery is deployed.

[0031] The embodiment of the present invention further provides a detection device for a negative electrode of a lithium battery, the device comprising:

[0032] An acquisition module, used to acquire at least one target sub-image collected for the negative electrode of the target lithium battery, each target sub-image including a lithium deposition area on the negative electrode of the target lithium battery;

[0033] A position determination module, used to determine the target position of each target sub-image on the negative electrode of the target lithium battery;

[0034] An area determination module is used to obtain a preset weight for a target position and determine a lithium deposition area of ​​a negative electrode of a target lithium battery according to the target sub-image and the corresponding weight;

[0035] The lithium deposition determination module is used to determine the lithium deposition situation of the negative electrode of the target lithium battery according to the lithium deposition area of ​​the negative electrode of the target lithium battery.

[0036] Optionally, obtain a module, including:

[0037] A first target image acquisition submodule, used to acquire a first target image including a negative electrode of a target lithium battery;

[0038] A second target image extraction submodule, used to extract a second target image from the first target image according to a preset lithium precipitation grayscale threshold;

[0039] The target sub-image generation sub-module is used to divide the second target image according to the target division method preset for the target lithium battery negative electrode to obtain at least one target sub-image.

[0040] Optionally, the target sub-image generation submodule is used to divide the first target image according to the target division method to obtain at least one third target image; and determine at least one target sub-image according to the intersection of the second target image and the at least one third target image.

[0041] Optionally, the second target image extraction submodule is used to determine the grayscale value of each pixel in the first target image, and determine at least one target pixel whose grayscale value is not less than a preset lithium deposition grayscale threshold; and generate the second target image based on the at least one target pixel.

[0042] Optionally, the area determination module includes:

[0043] An actual area determination submodule, used to determine the area of ​​a target sub-image;

[0044] A lithium deposition area determination submodule is used to determine the lithium deposition area of ​​a target subimage according to the area of ​​a target subimage and the weight corresponding to the target subimage;

[0045] The total lithium deposition area determination submodule is used to determine the lithium deposition area of ​​the negative electrode of the target lithium battery according to the lithium deposition areas of all target sub-images.

[0046] Optionally, the lithium deposition determination module is used to obtain the total area of ​​the negative electrode of the target lithium battery; and determine the lithium deposition situation of the negative electrode of the target lithium battery according to the ratio of the lithium deposition area of ​​the negative electrode of the target lithium battery to the total area of ​​the negative electrode of the target lithium battery.

[0047] Optionally, the device further comprises:

[0048] The abnormal relationship determination submodule is used to obtain the target abnormal parameters corresponding to the lithium battery; establish the lithium plating situation of the negative electrode of the target lithium battery and the corresponding relationship with the target abnormal parameters.

[0049] An embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the above-mentioned method for detecting a negative electrode of a lithium battery is implemented.

[0050] The embodiments of the present invention have the following advantages:

[0051] In an embodiment of the present invention, at least one target sub-image collected for the negative electrode of a target lithium battery is obtained, and each target sub-image includes a lithium deposition area on the negative electrode of the target lithium battery; the target position to which each target sub-image belongs on the negative electrode of the target lithium battery is determined; the weight preset for the target position is obtained, and the lithium deposition area of ​​the negative electrode of the target lithium battery is determined according to the target sub-image and the corresponding weight; the lithium deposition situation of the negative electrode of the target lithium battery is determined according to the lithium deposition area of ​​the negative electrode of the target lithium battery. Through the embodiment of the present invention, the lithium deposition situation of the negative electrode of the lithium battery is determined based on the difficulty of lithium deposition at different positions of the negative electrode of the lithium battery, thereby accurately measuring the lithium deposition situation of the entire negative electrode of the lithium battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solution of the present invention, the accompanying drawings required for use in the description of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0053] Figure 1 is a flow chart of the steps of a method for detecting a negative electrode of a lithium battery according to an embodiment of the present invention;

[0054] Figure 2 is a flow chart of the steps of another method for detecting a negative electrode of a lithium battery according to an embodiment of the present invention;

[0055] Figure 3 is a schematic diagram of a division method of a negative electrode of a lithium battery according to an embodiment of the present invention;

[0056] Figure 4 is a schematic structural diagram of a detection system according to an embodiment of the present invention;

[0057] Figure 5 It is a schematic diagram of a process of detecting a negative electrode of a lithium battery according to an embodiment of the present invention;

[0058] Figure 6 It is a schematic diagram of another process of detecting a negative electrode of a lithium battery according to an embodiment of the present invention;

[0059] Figure 7 It is a structural block diagram of a lithium battery negative electrode detection device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0060] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0061] Reference Figure 1 , shows a flow chart of a method for detecting a negative electrode of a lithium battery according to an embodiment of the present invention, which may include the following steps:

[0062] Step 101, obtaining at least one target sub-image collected for the negative electrode of a target lithium battery, each target sub-image including a lithium deposition area on the negative electrode of the target lithium battery;

[0063] In practical applications, when it is necessary to detect the lithium deposition condition of the negative electrode of a lithium battery, the negative electrode of the lithium battery can be separated from the lithium battery first; then, image data can be collected for the separated target negative electrode of the lithium battery.

[0064] Specifically, image data may be collected for each lithium deposition area on the negative electrode of the target lithium battery to generate at least one target sub-image.

[0065] Step 102, determining the target position of each target sub-image on the negative electrode of the target lithium battery;

[0066] Due to differences in battery structure design, preparation process, operating conditions, etc., the difficulty of lithium deposition in different areas of the negative electrode of the lithium battery is not the same. For example, lithium deposition is easy at the corners of the wound structure battery, while lithium deposition is easy at the edges of the laminated battery. If only the lithium deposition area is used as a single measurement indicator, it cannot effectively measure the lithium deposition situation of the entire lithium battery negative electrode.

[0067] In order to more accurately measure the lithium deposition situation of the entire negative electrode of the lithium battery, after acquiring at least one target sub-image, the embodiment of the present invention can first determine the target position corresponding to each target sub-image on the target negative electrode of the lithium battery.

[0068] Step 103, obtaining a preset weight for the target position, and determining the lithium deposition area of ​​the negative electrode of the target lithium battery according to the target sub-image and the corresponding weight;

[0069] As an example, when setting weights for various positions on the negative electrode of a lithium battery, different weights can be assigned to each position according to the difficulty of lithium deposition; for example, the position on the negative electrode of a lithium battery where lithium deposition is most difficult can be assigned a value of ω max , assign ω to the position on the negative electrode of the lithium battery where lithium is most likely to be deposited min , specific max and ω min It can be set according to actual conditions, and the embodiment of the present invention does not limit this.

[0070] After setting weights for each position on a negative electrode of a lithium battery, a correspondence between the weight and the negative electrode of the lithium battery can be established; for example, the size of the negative electrode of the lithium battery, or the production batch number of the lithium battery equipped with the negative electrode of the lithium battery can be obtained; then a correspondence between the basic information of the negative electrode of the lithium battery and the weight can be established.

[0071] Therefore, after obtaining the target position, the basic information of the target lithium battery negative electrode can be determined first, for example: determining the size of the target lithium battery negative electrode, or determining the target lithium battery deployed with the target lithium battery negative electrode; and then determining the weight corresponding to the target lithium battery negative electrode based on the pre-established correspondence between the basic information and the weight.

[0072] Then, the weight corresponding to each target position can be determined from the weight corresponding to the negative electrode of the target lithium battery.

[0073] Then, the weight corresponding to the target position can be assigned to the corresponding target sub-image; thus, the lithium deposition area of ​​the negative electrode of the target lithium battery can be determined according to the area of ​​the target sub-image and the corresponding weight.

[0074] Step 104: Determine the lithium deposition situation of the negative electrode of the target lithium battery according to the lithium deposition area of ​​the negative electrode of the target lithium battery.

[0075] After the lithium deposition area of ​​the negative electrode of the target lithium battery is determined, the lithium deposition situation of the target lithium battery can be determined according to the lithium deposition area.

[0076] As an example, the determined lithium plating situation can be output so as to quantitatively analyze the failure of the lithium battery based on the lithium plating situation; at the same time, the design of the lithium battery can also be optimized based on the lithium plating situation, which is not limited in the embodiment of the present invention.

[0077] In an embodiment of the present invention, at least one target sub-image collected for the negative electrode of a target lithium battery is obtained, and each target sub-image includes a lithium deposition area on the negative electrode of the target lithium battery; the target position to which each target sub-image belongs on the negative electrode of the target lithium battery is determined; the weight preset for the target position is obtained, and the lithium deposition area of ​​the negative electrode of the target lithium battery is determined according to the target sub-image and the corresponding weight; the lithium deposition situation of the negative electrode of the target lithium battery is determined according to the lithium deposition area of ​​the negative electrode of the target lithium battery. Through the embodiment of the present invention, the lithium deposition situation of the negative electrode of the lithium battery is determined based on the difficulty of lithium deposition at different positions of the negative electrode of the lithium battery, thereby accurately measuring the lithium deposition situation of the entire negative electrode of the lithium battery.

[0078] Reference Figure 2 , shows a flow chart of another method for detecting a negative electrode of a lithium battery according to an embodiment of the present invention, which may include the following steps:

[0079] Step 201, acquiring a first target image including a negative electrode of a target lithium battery;

[0080] The first target image may include the front side of the target lithium battery negative electrode, the back side of the target lithium battery negative electrode, or both the front side and the back side of the target lithium battery negative electrode, which is not limited in the embodiment of the present invention.

[0081] In practical applications, when it is necessary to detect the lithium plating condition of the negative electrode of the target lithium battery, the negative electrode of the target lithium battery can be separated from the target lithium battery first; specifically, the target lithium battery can be adjusted to 100% SOC (state of charge) first, and then separated in a drying room (temperature of 25±2°C, relative humidity less than 5%), and the embodiments of the present invention are not limited to this.

[0082] Then, image data of the disassembled target lithium battery negative electrode may be collected to generate a first target image including the target lithium battery negative electrode.

[0083] As an example, in order to remove background images and electrode edge areas that are not related to detection, the image collected for the target lithium battery negative electrode can be positioned and segmented to obtain a first target image that only includes the target lithium battery negative electrode. This embodiment of the present invention is not limited to this.

[0084] In one embodiment of the present invention, a high-resolution industrial camera, a corresponding lens, a lighting method and a light source can be used to capture the first target image; the industrial camera can be deployed in the form of a slide rail or a fixed bracket, and the embodiment of the present invention does not limit this.

[0085] Among them, high-resolution industrial cameras can use CCD (charge coupled device) or CMOS (Complementary Metal Oxide Semiconductor) linear or area array cameras with more than 500W pixels, and be equipped with lenses adapted to the camera. The lighting can be front lighting, side lighting, etc., and the light source can be annular, coaxial, planar, etc. The camera accuracy depends on the camera's resolution and field of view. X-direction accuracy (X-direction pixel value) = field of view (X direction) ÷ number of imaging chip pixels (X direction), Y-direction accuracy (Y-direction pixel value) = field of view (Y direction) ÷ number of imaging chip pixels (Y direction).

[0086] The best field of view means that the area of ​​interest of the visual system is filled with the field of view as much as possible. Generally, the smaller the best field of view, the higher the camera accuracy. The higher the camera resolution, the higher the system accuracy. The area of ​​interest in the image is within a clear focus and the lens distortion position is avoided as much as possible to ensure that the high-precision measurement and detection requirements are met.

[0087] Taking a 6500W pixel color array camera as an example, the resolution is 9344×7000, the field of view is 325mm×250mm, and the single pixel accuracy can reach 250mm / 7000pixel=0.036mm / pixel. The actual detection accuracy is about 3 pixels, the actual physical detection accuracy is 0.108mm, and the area accuracy is 0.108×0.108mm2.

[0088] Step 202: extracting a second target image from the first target image according to a preset lithium deposition grayscale threshold;

[0089] The preset grayscale threshold for lithium deposition can be set according to actual conditions. For example, n images of negative electrodes of lithium batteries that have undergone lithium deposition can be collected in advance under the same image acquisition conditions; then the grayscale value corresponding to the lithium deposition area in each image is determined; and the average value of the grayscale value is used as the preset grayscale threshold for lithium deposition:

[0090]

[0091] Among them, T i represents the grayscale value corresponding to the negative electrode of the i-th lithium battery, and threshold represents the preset lithium plating grayscale threshold.

[0092] After acquiring the first target image, a second target image can be extracted from the first target image according to a preset lithium deposition grayscale threshold; the second target image can include all lithium deposition areas on the negative electrode of the target lithium battery.

[0093] In one embodiment of the present invention, the second target image may be generated by the following sub-steps:

[0094] Sub-step 11, determining the grayscale value of each pixel in the first target image, and determining at least one target pixel whose grayscale value is not less than a preset lithium deposition grayscale threshold;

[0095] First, the grayscale value of each pixel in the first target image may be determined; then, the relationship between the grayscale value of the pixel and the preset lithium deposition grayscale threshold value may be compared respectively.

[0096] If the grayscale value is less than the preset lithium deposition grayscale threshold, the corresponding pixel point can be deleted; if the grayscale value is not less than the preset lithium deposition grayscale threshold, the corresponding pixel point can be used as the target pixel point.

[0097] For example:

[0098]

[0099] Among them, gray_value represents the gray value of the pixel, threshold represents the preset lithium deposition gray threshold, and pixel_result represents whether the pixel is used as a target pixel; if pixel_result is 1, the pixel is used as a target pixel; if pixel_result is 0, the pixel is not used as a target pixel, and the embodiment of the present invention does not limit this.

[0100] Sub-step 12: generating a second target image according to at least one target pixel point.

[0101] After comparing all the pixels in the first target image, at least one target pixel having a grayscale value not less than a preset lithium deposition grayscale threshold can be obtained; then, a second target image can be composed based on all the obtained target pixels.

[0102] Step 203: Divide the second target image according to the target division method preset for the target lithium battery negative electrode to obtain at least one target sub-image;

[0103] In practical applications, different area division methods can be set for different lithium battery negative electrodes; specifically, the difficulty of lithium deposition in each area on the lithium battery negative electrode may be different; therefore, the division method can be set in advance according to the difficulty of lithium deposition in each area, so as to divide the areas with the same or similar difficulty of lithium deposition together, such as Figure 3 As shown, there are 9 areas including 1, 2, 3, 4, 5, 6, 7, 8 and 9.

[0104] Thus, when dividing the second target image, the target division method pre-set for the target lithium battery negative electrode can be obtained first; specifically, corresponding division methods can be set in advance for lithium batteries of different production batches, and corresponding division methods can also be set for lithium battery negative electrodes of different sizes, thereby establishing a corresponding relationship between the basic information of the above-mentioned lithium battery negative electrode and the division method.

[0105] Then, the target division method corresponding to the target lithium battery negative electrode can be determined according to the correspondence between the basic information of the lithium battery negative electrode and the division method.

[0106] Then, the second target image may be divided according to the acquired target division method to obtain at least one target sub-image.

[0107] In one embodiment of the present invention, at least one target sub-image may be determined by the following sub-steps:

[0108] Sub-step 21: dividing the first target image according to the target division method to obtain at least one third target image;

[0109] First, according to the target division method, the first target image including the negative electrode of the lithium battery can be divided first, so as to obtain at least one third target image; wherein, the third target image can include an area on the negative electrode of the lithium battery with the same or similar difficulty of lithium deposition, and the area can be a complete and continuous area, or it can be a plurality of discontinuous sub-areas, and the embodiment of the present invention is not limited to this.

[0110] Sub-step 22: determining at least one target sub-image according to the intersection of the second target image and at least one third target image;

[0111] Then, an intersection between the second target image and at least one third target image may be determined; and based on the intersection, at least one target sub-image may be determined.

[0112] For example: the second target image is U, and at least one third target image is R 1 , R 2 , R 3 ……R n , then we can use U∩(R 1 , R 2 , R 3 ……R n ) as the target sub-image.

[0113] For example, the second target image includes U 1 and U 2 , where U 1 Corresponding to the positive side of the negative electrode of the target lithium battery, U 2Corresponding to the reverse side of the negative electrode of the target lithium battery, at least one third target image is R ij (where i=1 represents the front side, i=2 represents the back side, j ranges from 1 to n, representing n third target images, R ij represents the jth third target image on the i-th surface), then M ij As the target sub-image, M ij =U i ∩R ij .

[0114] Where i=1 represents the front side, i=2 represents the back side, j ranges from 1 to n, representing n third target sub-images, U i represents the second target image corresponding to the i-th face, M ij Represents the second target image U of the i-th surface within the j-th third target image i The intersection of .

[0115] Step 204, determining the target position of each target sub-image on the negative electrode of the target lithium battery;

[0116] In order to more accurately measure the lithium deposition situation of the entire negative electrode of the lithium battery, after acquiring at least one target sub-image, the embodiment of the present invention can first determine the target position corresponding to each target sub-image on the target negative electrode of the lithium battery.

[0117] Step 205: Obtain a preset weight for the target position;

[0118] After the target position is obtained, the basic information of the negative electrode of the target lithium battery can be determined first; then, the weight corresponding to the negative electrode of the target lithium battery can be determined according to the pre-established correspondence between the basic information and the weight.

[0119] Then, the weight corresponding to each target position can be determined from the weight corresponding to the negative electrode of the target lithium battery. Then, the weight corresponding to the target position can be assigned to the corresponding target sub-image.

[0120] Step 206: determine the area of ​​a target sub-image;

[0121] When determining the lithium deposition area of ​​the target sub-image, the area of ​​the target sub-image may be determined first; the area of ​​the target sub-image may represent the actual area of ​​the target sub-image.

[0122] Step 207: Determine the lithium deposition area of ​​a target sub-image according to the area of ​​the target sub-image and the weight corresponding to the target sub-image;

[0123] In order to accurately measure the lithium deposition situation of the entire lithium battery negative electrode, when determining the lithium deposition area of ​​a target sub-image, the lithium deposition area of ​​the target sub-image can be determined according to the actual area of ​​the target sub-image and the corresponding weight.

[0124] Specifically, the product of the actual area of ​​the target sub-image and the corresponding weight can be used as the lithium deposition area of ​​the target sub-image.

[0125] For example: The actual area of ​​the target sub-image is S Mij , the corresponding weight is ω j ; Then the lithium deposition area of ​​the target sub-image is S Mij *ω j .

[0126] Among them, S Mij It can represent the corresponding position of the jth third target image on the i-th surface.

[0127] Step 208: Determine the lithium deposition area of ​​the negative electrode of the target lithium battery according to the lithium deposition areas of all target sub-images;

[0128] After the lithium deposition area of ​​one target sub-image is determined, the lithium deposition area of ​​the next target sub-image may be determined, until the lithium deposition areas of all target sub-images are determined.

[0129] After the lithium deposition areas of all target sub-images are determined, the sum of the lithium deposition areas of all target sub-images may be used as the lithium deposition area of ​​the negative electrode of the target lithium battery.

[0130] Continuing from the previous example, the lithium deposition area of ​​the target lithium battery negative electrode is

[0131] in,

[0132] Step 209, obtaining the total area of ​​the negative electrode of the target lithium battery;

[0133] Before determining the lithium deposition situation of the negative electrode of the target lithium battery, the total area of ​​the negative electrode of the target lithium battery can be determined first; the total area of ​​the target lithium battery can include the sum of the area of ​​the region where lithium deposition does not occur and the area of ​​the region where lithium deposition occurs on the target lithium battery.

[0134] Step 210: Determine the lithium deposition situation of the negative electrode of the target lithium battery according to the ratio of the lithium deposition area of ​​the negative electrode of the target lithium battery to the total area of ​​the negative electrode of the target lithium battery.

[0135] Then, the ratio of the lithium deposition area of ​​the negative electrode of the target lithium battery to the total area of ​​the negative electrode of the target lithium battery can be calculated, and then the lithium deposition situation of the negative electrode of the target lithium battery can be determined based on the ratio.

[0136] As an example, if the target lithium battery includes multiple negative electrodes, the sum of the lithium deposition areas of all the negative electrodes may be taken as the lithium deposition area of ​​the negative electrode of the target lithium battery.

[0137] Continuing from the previous example: S' k is the lithium deposition area on the front and back of the negative electrode of the target lithium battery, then the lithium deposition area of ​​the negative electrode of the target lithium battery

[0138] In one embodiment of the present invention, after determining the lithium deposition condition of the negative electrode of the target lithium battery, the following steps may also be included:

[0139] Obtain target abnormal parameters corresponding to the lithium battery; establish the lithium plating situation of the negative electrode of the target lithium battery and the corresponding relationship between the target abnormal parameters.

[0140] In practical applications, the abnormality of a lithium battery may be related to lithium plating; therefore, after determining the lithium plating situation of the negative electrode of the target lithium battery, the target abnormality parameters corresponding to the target lithium battery can also be obtained.

[0141] As an example, the target abnormal parameter may be obtained after testing the target lithium battery, such as a total thermal safety index.

[0142] After determining the lithium deposition situation of the target lithium battery negative electrode and the target abnormal parameters, a corresponding relationship between the lithium deposition situation of the target lithium battery negative electrode and the target abnormal parameters can be established so that the corresponding abnormal parameters of the lithium battery can be determined based on the lithium deposition situation.

[0143] For example, 2n lithium batteries may be taken to conduct n groups of experiments, and each group of samples may be numbered as X1, X2, X3, ..., Xn. The same test may be conducted on m lithium batteries in each group, and they may be numbered as (X11, X12, ..., X1m), (X21, X21, ..., X2m), ..., (Xn1, Xn2, ..., Xnm), so that each group of lithium batteries is in the same lithium deposition state, and each group is in a different lithium deposition state. The same group of lithium batteries may be divided into two groups as parallel groups, one of which may be subjected to a disassembly experiment, and the lithium deposition situation (e.g., lithium deposition percentage) may be determined through the above steps 201 to 210. The other group of lithium batteries may be subjected to an ARC (accelerating rate calorimeter) test to obtain a thermal safety comprehensive index K value, and the variation trend or correlation between the lithium deposition percentage and the K value may be analyzed through the experimental results.

[0144] Specifically, the ARC test can be used to obtain a temperature-time (Tt) curve showing the thermal characteristics of lithium batteries from self-heating to thermal runaway. Since the test is conducted in an adiabatic environment, the data reveals the inherent thermal characteristics of lithium batteries. When the battery temperature rise rate is continuously greater than 0.02°C / min, it is marked as T0 , whose corresponding time mark is t 1 When the battery temperature rise rate reaches 1°C / min, it can be considered the beginning of thermal runaway. The temperature at this time is called T c , time marked as t 2 .

[0145] Therefore, from the perspective of evaluating battery safety, the self-heating starting temperature T 0 , thermal runaway critical temperature T c , Thermal runaway brewing time (t 2 -t 1 ) are three very important parameters. Using these three parameters, the safety of the battery can be evaluated from the perspective of battery thermal stability, and the comprehensive index K value representing thermal safety can be formulated through mathematical formulas. According to experience, the K value is divided into three levels to represent the safety risk of the battery cell. The three levels are low risk, medium risk, and high risk. When K≥6, it is judged as low risk, when 4≤K≤6, it is judged as medium risk, and when K≤4, it is judged as high risk.

[0146] Therefore, the safety failure risk level can be determined by the lithium plating percentage P.

[0147] As shown in Table 1:

[0148]

[0149]

[0150] In an embodiment of the present invention, a first target image including a target lithium battery negative electrode is obtained; a second target image is extracted from the first target image according to a preset lithium deposition grayscale threshold; the second target image is divided according to a target division method preset for the target lithium battery negative electrode to obtain at least one target sub-image; the target position to which each target sub-image belongs on the target lithium battery negative electrode is determined; a weight preset for the target position is obtained; the area of ​​a target sub-image is determined; the lithium deposition area of ​​a target sub-image is determined according to the area of ​​a target sub-image and the weight corresponding to the target sub-image; the lithium deposition area of ​​the target lithium battery negative electrode is determined according to the lithium deposition areas of all target sub-images; the total area of ​​the target lithium battery negative electrode is obtained; the lithium deposition situation of the target lithium battery negative electrode is determined according to the ratio of the lithium deposition area of ​​the target lithium battery negative electrode to the total area of ​​the target lithium battery negative electrode. Through the embodiment of the present invention, the lithium deposition situation of the lithium battery negative electrode is determined based on the difficulty of lithium deposition at different positions of the lithium battery negative electrode, thereby accurately measuring the lithium deposition situation of the entire lithium battery negative electrode.

[0151] It should be noted that, for the sake of simplicity, the method embodiments are described as a series of action combinations, but those skilled in the art should be aware that the embodiments of the present invention are not limited by the order of the actions described, because according to the embodiments of the present invention, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions involved are not necessarily required by the embodiments of the present invention.

[0152] Reference Figure 4 , showing a schematic diagram of the structure of a detection system according to an embodiment of the present invention, the detection system can be deployed with the above-mentioned detection method for the negative electrode of a lithium battery.

[0153] Specifically, the detection system may include: an industrial camera 400 , a lens 401 , a light source 402 , a lithium battery negative electrode 403 , a pole piece fixture device 404 , a darkroom device for image acquisition 405 , an industrial computer 406 and a display 407 .

[0154] The pole piece fixture device 404 and the dark chamber device 405 for image acquisition can be deployed on the mechanical platform. The pole piece fixture device 404 can be used to fix the negative electrode 403 of the lithium battery; the dark chamber device 405 for image acquisition can refer to a dark chamber used to acquire image data of the negative electrode 403 of the lithium battery. The mechanical platform can also include: an image acquisition device fixing device and other supporting mechanical devices. The image acquisition device fixing device can refer to a device used to fix the image acquisition device.

[0155] The industrial camera 400, the lens 401, and the light source 402 can be deployed in an image acquisition system; the image acquisition system can also include a light source controller and an image acquisition card and other related image acquisition devices. The image acquisition card can receive analog signals or digital signals from the industrial camera 400 and convert the signals into digital images that can be processed by a PC (personal computer).

[0156] An image processing system and a database system may be deployed in the industrial computer 406. The image processing system may include: lithium analysis detection human-computer interaction software and image processing algorithm; the image processing algorithm may refer to the above-mentioned lithium battery negative electrode detection method. The database system may include: an image storage module, a lithium battery production batch number, a negative electrode size and other basic information and a corresponding series of test results and other information storage module, an operator and operation time storage module, and the database should be scalable.

[0157] More specifically, the image processing module may include four image processing units: pole piece detection area positioning, pole piece detection area division, pole piece lithium deposition area extraction, and lithium deposition area calculation.

[0158] Pole piece detection area positioning unit: The image processing algorithm locates and segments the effective detection area in the image collected for the negative electrode 403 of the lithium battery. The main purpose is to remove the background and pole piece edge area that are not related to the detection, and only select the effective detection area to obtain the first target image.

[0159] The pole piece detection area division unit is: based on the effective area, the effective area is further divided according to the acquired effective area positioning coordinate information, so as to obtain at least one third target image.

[0160] Pole lithium deposition area extraction unit: The image processing algorithm will extract the lithium deposition pixels within the effective detection area according to the preset lithium deposition grayscale threshold, thereby extracting the second target image from the first target image.

[0161] The lithium deposition area calculation unit determines at least one target sub-image according to the intersection of the second target image and at least one third target image; and determines the lithium deposition area of ​​the negative electrode 403 of the lithium battery according to the target sub-image and the corresponding weight.

[0162] In one embodiment of the present invention, the detection system may further include an electrical control system, an image processing system and a database system. The electrical control system may include: an equipment start / stop control unit, an alarm unit, a power supply unit, a circuit protection unit and other related electrical equipment.

[0163] like Figure 5 , S100, before formal image acquisition, it is necessary to input basic information such as operator, battery production batch number, size, etc. into the detection system in advance. The input information can accurately classify and mark the negative electrode of the lithium battery, which is convenient for storage and recording in the database and later retrieval;

[0164] S200, disassemble the battery and obtain n images; adjust the state of the samples to 100% SOC (state of charge) and disassemble them in a dry room (temperature 25±2°C, relative humidity ≤5%);

[0165] S300, flattening the negative electrodes disassembled from the lithium battery one by one and clamping them on the electrode clamp device, and then collecting and saving images of the front and back sides of each negative electrode;

[0166] S400, importing the images collected in step S300 into the image processing system, and the image processing algorithm will perform operations on each image according to the set procedures and parameters;

[0167] After the image processing in step S500 and step S400 is completed, the system will summarize the detection results of each image, and then accumulate the lithium deposition weighted area detected by each negative electrode of each lithium battery and divide it by the total effective detection area of ​​the negative electrode to obtain the percentage result of the lithium deposition area of ​​the lithium battery, and output the percentage result of the lithium deposition area of ​​the lithium battery;

[0168] S600, conduct ARC test on parallel samples of each lithium battery to obtain the K value, a comprehensive thermal safety index, and divide the battery risk level into three levels based on experience, i.e. low risk, medium risk, and high risk. Combined with the correlation between the battery lithium deposition area percentage result obtained in step S500 and the trend of the K value, the battery lithium deposition degree is determined as low, medium, or high risk level;

[0169] The further implementation description of the image acquisition system corresponding to S300 is as follows:

[0170] The communication between industrial cameras and industrial computers is achieved through image acquisition cards. When triggered, industrial cameras transmit analog or digital signals to the image acquisition card, which then converts the analog or digital signals into digital images that can be processed by the industrial computer. The choice of camera, lens, light source and lighting method determines the image quality and accuracy.

[0171] In order to more accurately detect the lithium deposition status of the electrode, the image acquisition system of this solution uses a high-resolution CCD area array color industrial camera with more than 500W pixels, and is equipped with a high-resolution 35mm focal length industrial lens adapted to the camera. The lighting method uses front lighting, and the light source uses a plane light source with a central opening. The embodiment uses a 6500W pixel color area array camera as an example. The resolution of the camera is 9344×7000, the field of view is 325mm×250mm, and the single pixel accuracy can reach:

[0172]

[0173] The actual detection accuracy is about 3 pixels, that is, the actual physical detection accuracy is 0.108mm, and the area accuracy is 0.108×0.108mm 2 .

[0174] like Figure 6 , a further detailed implementation description of the image processing system corresponding to S400 is given:

[0175] S401, positioning the effective detection area of ​​a single negative electrode image;

[0176] S402, fine segmentation of the effective detection area of ​​the single negative electrode image;

[0177] S403, extracting lithium deposition areas from a single negative electrode image;

[0178] S404, calculating the lithium deposition area of ​​a single negative electrode image;

[0179] S405. The lithium deposition area percentage of the negative electrode of the lithium battery is calculated by accumulating the lithium deposition area of ​​the 2n negative electrode images.

[0180] In an embodiment of the present invention, at least one target sub-image collected for the negative electrode of a target lithium battery is obtained, and each target sub-image includes a lithium deposition area on the negative electrode of the target lithium battery; the target position to which each target sub-image belongs on the negative electrode of the target lithium battery is determined; the weight preset for the target position is obtained, and the lithium deposition area of ​​the negative electrode of the target lithium battery is determined according to the target sub-image and the corresponding weight; the lithium deposition situation of the negative electrode of the target lithium battery is determined according to the lithium deposition area of ​​the negative electrode of the target lithium battery. Through the embodiment of the present invention, the lithium deposition situation of the negative electrode of the lithium battery is determined based on the difficulty of lithium deposition at different positions of the negative electrode of the lithium battery, thereby accurately measuring the lithium deposition situation of the entire negative electrode of the lithium battery.

[0181] Reference Figure 7 , shows a schematic structural diagram of a lithium battery negative electrode detection device according to an embodiment of the present invention, which may include the following modules:

[0182] An acquisition module 701 is used to acquire at least one target sub-image collected for the negative electrode of a target lithium battery, each target sub-image including a lithium deposition area on the negative electrode of the target lithium battery;

[0183] A position determination module 702 is used to determine the target position of each target sub-image on the negative electrode of the target lithium battery;

[0184] The area determination module 703 is used to obtain the weight preset for the target position, and determine the lithium deposition area of ​​the negative electrode of the target lithium battery according to the target sub-image and the corresponding weight;

[0185] The lithium deposition determining module 704 is used to determine the lithium deposition situation of the negative electrode of the target lithium battery according to the lithium deposition area of ​​the negative electrode of the target lithium battery.

[0186] In an optional embodiment of the present invention, the acquisition module 701 includes:

[0187] A first target image acquisition submodule, used to acquire a first target image including a negative electrode of a target lithium battery;

[0188] A second target image extraction submodule, used to extract a second target image from the first target image according to a preset lithium precipitation grayscale threshold;

[0189] The target sub-image generation sub-module is used to divide the second target image according to the target division method preset for the target lithium battery negative electrode to obtain at least one target sub-image.

[0190] In an optional embodiment of the present invention, the target sub-image generation submodule is used to divide the first target image according to the target division method to obtain at least one third target image; and determine at least one target sub-image according to the intersection of the second target image and at least one third target image.

[0191] In an optional embodiment of the present invention, the second target image extraction submodule is used to determine the grayscale value of each pixel in the first target image, and determine at least one target pixel whose grayscale value is not less than a preset lithium deposition grayscale threshold; and generate a second target image based on the at least one target pixel.

[0192] In an optional embodiment of the present invention, the area determination module 703 includes:

[0193] An actual area determination submodule, used to determine the area of ​​a target sub-image;

[0194] A lithium deposition area determination submodule is used to determine the lithium deposition area of ​​a target subimage according to the area of ​​a target subimage and the weight corresponding to the target subimage;

[0195] The total lithium deposition area determination submodule is used to determine the lithium deposition area of ​​the negative electrode of the target lithium battery according to the lithium deposition areas of all target sub-images.

[0196] In an optional embodiment of the present invention, the lithium deposition determination module 704 is used to obtain the total area of ​​the negative electrode of the target lithium battery; and determine the lithium deposition situation of the negative electrode of the target lithium battery based on the ratio of the lithium deposition area of ​​the negative electrode of the target lithium battery to the total area of ​​the negative electrode of the target lithium battery.

[0197] In an optional embodiment of the present invention, the device further comprises:

[0198] The abnormal relationship determination submodule is used to obtain the target abnormal parameters corresponding to the lithium battery; establish the lithium plating situation of the negative electrode of the target lithium battery and the corresponding relationship with the target abnormal parameters.

[0199] In an embodiment of the present invention, at least one target sub-image collected for the negative electrode of a target lithium battery is obtained, and each target sub-image includes a lithium deposition area on the negative electrode of the target lithium battery; the target position to which each target sub-image belongs on the negative electrode of the target lithium battery is determined; the weight preset for the target position is obtained, and the lithium deposition area of ​​the negative electrode of the target lithium battery is determined according to the target sub-image and the corresponding weight; the lithium deposition situation of the negative electrode of the target lithium battery is determined according to the lithium deposition area of ​​the negative electrode of the target lithium battery. Through the embodiment of the present invention, the lithium deposition situation of the negative electrode of the lithium battery is determined based on the difficulty of lithium deposition at different positions of the negative electrode of the lithium battery, thereby accurately measuring the lithium deposition situation of the entire negative electrode of the lithium battery.

[0200] An embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the above-mentioned method for detecting a negative electrode of a lithium battery is implemented.

[0201] As for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0202] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0203] Those skilled in the art will appreciate that the embodiments of the present invention may be provided as methods, devices, or computer program products. Therefore, the embodiments of the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the embodiments of the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0204] The embodiments of the present invention are described with reference to the flowcharts and / or block diagrams of the methods, terminal devices (systems), and computer program products according to the embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing terminal device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing terminal device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0205] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing terminal device to operate in a specific manner, so that the instructions stored in the computer readable memory produce a manufactured product including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0206] These computer program instructions can also be loaded onto a computer or other programmable data processing terminal device so that a series of operating steps are executed on the computer or other programmable terminal device to produce a computer-implemented process, thereby providing instructions for executing on the computer or other programmable terminal device to implement the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0207] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present invention.

[0208] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or terminal device including the elements.

[0209] The above provides a detailed introduction to a detection method, device and medium for the negative electrode of a lithium battery, and a detection system. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for a general technician in this field, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A method for detecting a negative electrode of a lithium battery, characterized in that: The method comprises: Acquire at least one target sub-image collected for the negative electrode of a target lithium battery, each target sub-image including a lithium deposition area on the negative electrode of the target lithium battery; Determine the target position of each target sub-image on the negative electrode of the target lithium battery; Obtaining a preset weight for the target position, and determining the lithium deposition area of ​​the negative electrode of the target lithium battery according to the target sub-image and the corresponding weight; wherein different weights are assigned to each position according to the difficulty of lithium deposition; Determining the lithium deposition situation of the negative electrode of the target lithium battery according to the lithium deposition area of ​​the negative electrode of the target lithium battery; The step of acquiring at least one target sub-image collected for the negative electrode of the target lithium battery includes: Acquire a first target image including the negative electrode of the target lithium battery; Extracting a second target image from the first target image according to a preset lithium deposition grayscale threshold; According to the target division method preset for the target lithium battery negative electrode, the first target image is divided to obtain at least one third target image; wherein the target division method is set in advance according to the difficulty of lithium deposition in each area; determining the at least one target sub-image according to an intersection of the second target image and the at least one third target image; The step of determining the lithium deposition area of ​​the negative electrode of the target lithium battery according to the target sub-image and the corresponding weight includes: Determine the area of ​​a target sub-image; Determining a lithium deposition area of ​​the target sub-image according to the area of ​​the target sub-image and a weight corresponding to the target sub-image; According to the lithium deposition areas of all target sub-images, the lithium deposition area of ​​the negative electrode of the target lithium battery is determined.

2. The method according to claim 1, characterized in that The step of extracting the second target image from the first target image according to a preset lithium deposition grayscale threshold comprises: Determine the grayscale value of each pixel in the first target image, and determine at least one target pixel whose grayscale value is not less than the preset lithium deposition grayscale threshold; The second target image is generated according to the at least one target pixel point.

3. The method according to claim 1, characterized in that The step of determining the lithium deposition situation of the negative electrode of the target lithium battery according to the lithium deposition area of ​​the negative electrode of the target lithium battery comprises: Obtaining the total area of ​​the negative electrode of the target lithium battery; The lithium deposition situation of the negative electrode of the target lithium battery is determined according to the ratio of the lithium deposition area of ​​the negative electrode of the target lithium battery to the total area of ​​the negative electrode of the target lithium battery.

4. The method according to any one of claims 1 to 3, characterized in that: The method further comprises: Obtain target abnormal parameters corresponding to lithium batteries; Establish the corresponding relationship between the lithium plating condition of the negative electrode of the target lithium battery and the target abnormal parameter.

5. A detection system, characterized in that: The detection system is equipped with a method for detecting a negative electrode of a lithium battery as described in any one of claims 1 to 4 above.

6. A detection device for a negative electrode of a lithium battery, characterized in that: The device comprises: An acquisition module, used to acquire at least one target sub-image collected for the negative electrode of a target lithium battery, each target sub-image including a lithium deposition area on the negative electrode of the target lithium battery; A position determination module, used to determine the target position of each target sub-image on the negative electrode of the target lithium battery; An area determination module is used to obtain a preset weight for the target position, and determine the lithium deposition area of ​​the negative electrode of the target lithium battery according to the target sub-image and the corresponding weight; wherein different weights are assigned to each position according to the difficulty of lithium deposition; A lithium deposition determination module, used to determine the lithium deposition situation of the negative electrode of the target lithium battery according to the lithium deposition area of ​​the negative electrode of the target lithium battery; The acquisition module is used to acquire a first target image including the target lithium battery negative electrode; extract a second target image from the first target image according to a preset lithium plating gray threshold; divide the first target image according to a target division method preset for the target lithium battery negative electrode to obtain at least one third target image; wherein the target division method is set in advance according to the difficulty of lithium plating in each area; and determine the at least one target sub-image according to the intersection of the second target image and the at least one third target image; The area determination module comprises: An actual area determination submodule, used to determine the area of ​​a target sub-image; A lithium deposition area determination submodule, used to determine the lithium deposition area of ​​the target subimage according to the area of ​​the target subimage and the weight corresponding to the target subimage; The total lithium deposition area determination submodule is used to determine the lithium deposition area of ​​the negative electrode of the target lithium battery according to the lithium deposition areas of all target sub-images.

7. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method for detecting a negative electrode of a lithium battery as claimed in any one of claims 1 to 4 is implemented.

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