A lithium battery coating process defect correction closed-loop method and system

Abstract

The application discloses a kind of lithium battery coating process defect correction closed loop method, industrial camera and linear light source are provided on coating back roll;The method comprises: obtaining the coating image of lithium battery coating photographed by the industrial camera;The coating image is carried out gray scale processing, and gray scale image is obtained;According to the preset gray scale threshold, the gray scale value of each pixel point in the gray scale image is binarized, and a binary image is obtained;The width of coating defect is obtained by processing the binary image;Based on the preset unit movement, the movement of coating die is determined according to the width of coating defect, and the movement of coating die is controlled according to the movement of coating die, coating defect is corrected, and the quality of lithium battery coating is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of lithium battery coating defect correction technology, and in particular to a closed-loop method and system for correcting defects in lithium battery coating processes. Background Technology

[0002] Lithium-ion batteries are a type of battery that uses lithium metal or lithium alloys as positive / negative electrode materials and a non-aqueous electrolyte solution. Lithium-ion batteries have advantages such as high operating voltage, high energy density (light weight), long cycle life, no memory effect, and no pollution. They are also safe, reliable, and can be charged and discharged quickly, making them the main power source for various electronic products. Therefore, as lithium-ion batteries are increasingly used in various industries, people have higher requirements for their performance. During the production process of lithium-ion batteries, the positive and negative electrode materials and separators require a slurry coating step, and the coating effect directly affects the battery's capacity, safety, and other performance characteristics.

[0003] In the coating process of the lithium battery industry, long strip-shaped defects, such as long scratches and vertical long foil leaks, often occur, causing a large number of defects on the coating surface and seriously affecting the coating quality. Therefore, there is an urgent need for a closed-loop method for correcting defects in the lithium battery coating process to achieve the correction of lithium battery coating defects. Summary of the Invention

[0004] The purpose of this invention is to provide a closed-loop method and system for correcting defects in lithium battery coating process, which solves the problem of long strip-shaped defects in lithium battery coating process, resulting in a large number of defects on the coating surface and seriously affecting the coating quality.

[0005] This invention provides a closed-loop method for correcting defects in lithium battery coating processes, wherein an industrial camera and a linear light source are installed on the coating back roller;

[0006] The method includes:

[0007] Acquire coating images of lithium battery coating captured by the industrial camera;

[0008] The coated image is converted to grayscale to obtain a grayscale image;

[0009] The gray values ​​of each pixel in the grayscale image are binarized according to a preset grayscale threshold to obtain a binarized image.

[0010] The width of the coating defect is obtained by processing the binarized image.

[0011] Based on a preset unit movement amount, the movement amount of the coating die head is determined according to the width of the coating defect, and the movement of the coating die head is controlled according to the movement amount of the coating die head to correct the coating defect.

[0012] In some embodiments of this application, the industrial camera is positioned above the coating back roller, the linear light source is positioned to the side of the coating back roller, and the illumination point of the linear light source is the acquisition point of the industrial camera.

[0013] In some embodiments of this application, the coating image is an image containing the left electrode and the right electrode of the lithium battery.

[0014] In some embodiments of this application, the grayscale values ​​of each pixel in the grayscale image are binarized according to a preset grayscale threshold, including:

[0015] Preset grayscale threshold g;

[0016] Determine the grayscale value G of each pixel in the grayscale image;

[0017] The grayscale threshold g is compared with the grayscale value G, and the binarized grayscale value G0 of each pixel in the grayscale image is determined according to the comparison result.

[0018] When the gray value G ≥ gray threshold g, the binarized gray value G0 is 255;

[0019] When the gray value G < gray threshold g, the binarized gray value G0 is 0.

[0020] In some embodiments of this application, the coating defects include intermediate foil leaks and long scratches.

[0021] In some embodiments of this application, the binarized image is processed to obtain the width of the coating defect, including:

[0022] The substrate region is determined based on the binarized grayscale values ​​of the pixels in the binarized image;

[0023] Obtain the width value of the substrate region, and determine the type of the substrate region based on the preset width value;

[0024] If the width of the substrate region is equal to the preset width value, then the substrate region is an electrode region;

[0025] If the width value of the substrate area is not equal to the preset width value, then the substrate area is a defective area;

[0026] The width of the coating defect is determined based on the width value of the defect area.

[0027] In some embodiments of this application, determining the substrate region based on the binarized grayscale values ​​of the pixels in the binarized image includes:

[0028] When the binarized gray value G0 of a pixel in the binarized image is 0, the pixel is defined as belonging to the substrate region.

[0029] When the binarized gray value G0 of a pixel in the binarized image is 255, the pixel is defined as belonging to the coating area.

[0030] In some embodiments of this application, before determining the movement amount of the coating die head based on the width of the coating defect according to a preset unit movement amount, the method further includes:

[0031] Obtain the historical movement of the coating die head and the corresponding change in coating width;

[0032] Determine the ratio between the historical movement amount and the change in coating width, and determine the unit movement amount based on the ratio.

[0033] In some embodiments of this application, the movement of the coating die head is determined based on a preset unit movement amount and the width of the coating defect, including:

[0034] Determine the preset unit movement amount 'a' and the width of the coating defect 'b';

[0035] Determine the product between the unit movement amount a and the width b of the coating defect, and determine the movement amount c of the coating die head based on the product;

[0036] The formula for calculating the movement amount c of the coating die head is: c = a * b.

[0037] This invention also provides a closed-loop system for correcting defects in lithium battery coating processes, comprising:

[0038] An industrial camera is positioned above the coating back roller and is used to capture coating images of lithium battery coating.

[0039] A linear light source is disposed on the side of the coating back roller, and the illumination point of the linear light source is the acquisition point of the industrial camera;

[0040] A correction closed-loop system, comprising an acquisition module, a processing module, and a control module;

[0041] The acquisition module is used to acquire coating images of lithium battery coating captured by the industrial camera;

[0042] The processing module is used to determine the amount of movement of the coating die head based on the coating image;

[0043] The control module is used to control the movement of the coating die head according to the amount of movement of the coating die head, so as to correct coating defects;

[0044] The processing module is used to perform grayscale processing on the coating image to obtain a grayscale image, perform binarization processing on the grayscale value of each pixel in the grayscale image according to a preset grayscale threshold to obtain a binarized image, process the binarized image to obtain the width of the coating defect, and determine the movement amount of the coating die head based on the width of the coating defect according to a preset unit movement amount.

[0045] This invention discloses a closed-loop method for correcting defects in lithium battery coating process. The method acquires coating images of lithium batteries taken by an industrial camera, performs grayscale and binarization processing on the coating images, determines the defect areas of lithium battery coating, obtains the width of the coating defects, and determines the movement amount of the coating die head based on the width of the coating defects.

[0046] This invention uses an industrial camera and a closed-loop correction system to detect defects on the coating surface of lithium batteries in real time. Then, it controls the coating die head to move, realizing automatic closed-loop correction of coating defects without manual operation. This improves defect detection efficiency, reduces detection costs, and ensures the quality of lithium battery coating.

[0047] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0048] Figure 1 This is a schematic flowchart of a closed-loop method for defect correction in lithium battery coating process according to the present invention.

[0049] Figure 2 The mounting positions of the industrial camera and linear light source in this embodiment of the invention are shown.

[0050] Figure 3 This is an example diagram of coating defects in an embodiment of the present invention;

[0051] Figure 4 This is a structural block diagram of the correction closed-loop system in an embodiment of the present invention.

[0052] Figure Labels

[0053] 1. Industrial camera; 2. Linear light source; 3. Coating back roller. Detailed Implementation

[0054] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0055] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0056] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments of the present invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof, without excluding other elements or objects. The terms "first," "second," and similar words used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "upper," "lower," "left," "right," "front," "rear," "vertical," "horizontal," "side," and "bottom," indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are merely relational terms determined for the convenience of describing the structural relationships of the various components or elements of the present invention, and do not specifically refer to any component or element in the invention, nor should they be construed as limiting the invention. Terms such as "fixed," "connected," and "linked," etc., should be interpreted broadly, indicating that it can be a fixed connection, an integral connection, or a detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. For researchers or technicians in the field, the specific meaning of the above terms in this invention can be determined according to the specific circumstances, and they should not be construed as limitations on this invention.

[0057] Example

[0058] In the coating process of the lithium battery industry, long strip-shaped defects, such as long scratches and vertical long foil leaks, often occur, causing a large number of defects on the coating surface and seriously affecting the coating quality. Therefore, there is an urgent need for a closed-loop method for correcting defects in lithium battery coating process to achieve the correction of lithium battery coating defects.

[0059] This invention provides a closed-loop method for correcting defects in lithium battery coating processes, wherein an industrial camera 1 and a linear light source 2 are mounted on the coating back roller 3; as shown... Figure 1 As shown, the method includes:

[0060] S1, acquire the coating image of the lithium battery coating captured by the industrial camera 1.

[0061] S2, perform grayscale processing on the coating image to obtain a grayscale image.

[0062] S3, perform binarization processing on the grayscale values ​​of each pixel in the grayscale image according to the preset grayscale threshold to obtain a binarized image.

[0063] S4, process the binarized image to obtain the width of the coating defect.

[0064] S5, based on a preset unit movement amount, determine the movement amount of the coating die head according to the width of the coating defect, and control the movement of the coating die head according to the movement amount of the coating die head to correct the coating defect.

[0065] In some embodiments of this application, such as Figure 2 As shown, the installation positions of the industrial camera 1 and the linear light source 2 have been improved to make the captured coating images clearer. The industrial camera 1 is positioned above the coating back roller 3, and the linear light source 2 is positioned to the side of the coating back roller 3. The illumination point of the linear light source 2 is the acquisition point of the industrial camera 1.

[0066] In this embodiment, the linear light source 2 is continuously turned on, and the industrial camera 1 captures the coating image, ensuring that the coating image includes the left electrode and the right electrode of the lithium battery.

[0067] In some embodiments of this application, the coating image has been improved to make subsequent analysis and processing more accurate. The coating image is an image containing the left electrode and the right electrode of the lithium battery.

[0068] In some embodiments of this application, a method for binarization processing is disclosed, which performs binarization processing on the grayscale values ​​of each pixel in the grayscale image according to a preset grayscale threshold, including:

[0069] Preset grayscale threshold g.

[0070] Determine the grayscale value G of each pixel in the grayscale image.

[0071] The grayscale threshold g is compared with the grayscale value G, and the binarized grayscale value G0 of each pixel in the grayscale image is determined based on the comparison result.

[0072] When the gray value G ≥ gray threshold g, the binarized gray value G0 is 255.

[0073] When the gray value G < gray threshold g, the binarized gray value G0 is 0.

[0074] In this embodiment, the substrate in the coating image is light-colored, while the slurry coating is dark-colored, and the grayscale values ​​of the two are quite different. Therefore, a grayscale threshold is set, and binarization processing is performed based on the grayscale threshold to determine the binarized grayscale value.

[0075] In some embodiments of this application, the types of coating defects are disclosed, including intermediate foil leakage and long scratches.

[0076] In some embodiments of this application, such as Figure 3As shown, a specific method for determining the width of a coating defect is disclosed, which involves processing the binarized image to obtain the width of the coating defect, including:

[0077] The substrate region is determined based on the binarized grayscale values ​​of the pixels in the binarized image.

[0078] Obtain the width value of the substrate area, and determine the type of the substrate area based on the preset width value.

[0079] If the width of the substrate region is equal to the preset width value, then the substrate region is an electrode region.

[0080] If the width value of the substrate area is not equal to the preset width value, then the substrate area is a defective area.

[0081] The width of the coating defect is determined based on the width value of the defect area.

[0082] In this embodiment, since the width of the electrode area is fixed, when the width of the substrate area is consistent with the preset width value, the substrate area is determined to be the electrode area; when the width of the substrate area is inconsistent with the preset width value, the substrate area is determined to be the defect area, and the width of the defect area is set to the width of the coating defect.

[0083] In this embodiment, the distance between adjacent electrode regions is obtained. If the distance is a known electrode distance, the electrode region is determined to be the left or right electrode of the lithium battery.

[0084] In some embodiments of this application, determining the substrate region based on the binarized grayscale values ​​of the pixels in the binarized image includes:

[0085] When the binarized grayscale value G0 of a pixel in the binarized image is 0, the pixel is defined as belonging to the substrate region.

[0086] When the binarized gray value G0 of a pixel in the binarized image is 255, the pixel is defined as belonging to the coating area.

[0087] In this embodiment, because the color depth difference between the substrate and the slurry coating is large, when the binarized gray value of a pixel in the processed binarized image is 0, the area to which the pixel belongs is the substrate area; when the binarized gray value is 255, the area to which the pixel belongs is the coating area.

[0088] In some embodiments of this application, before determining the movement amount of the coating die head based on the width of the coating defect according to a preset unit movement amount, the method further includes:

[0089] Obtain the historical movement of the coating die head and the corresponding change in coating width.

[0090] Determine the ratio between the historical movement amount and the change in coating width, and determine the unit movement amount based on the ratio.

[0091] In this embodiment, by controlling a certain amount of movement of the coating die head and measuring the change in coating width corresponding to the movement of the coating die head, the unit movement amount is determined based on the relationship between the movement amount of the coating die head and the change in coating width.

[0092] In some embodiments of this application, the movement of the coating die head is determined based on a preset unit movement amount and the width of the coating defect, including:

[0093] Determine the preset unit movement amount 'a' and the width of the coating defect 'b'.

[0094] Determine the product between the unit movement amount a and the width b of the coating defect, and determine the movement amount c of the coating die head based on the product.

[0095] The formula for calculating the movement amount c of the coating die head is: c = a * b.

[0096] This invention also provides a closed-loop system for correcting defects in lithium battery coating processes, such as... Figure 4 As shown, it includes:

[0097] An industrial camera 1 is positioned above the coating back roller 3 and is used to capture coating images of lithium battery coating.

[0098] Linear light source 2 is disposed on the side of the coating back roller 3, and the illumination point of the linear light source 2 is the acquisition point of the industrial camera 1.

[0099] A correction closed-loop system, comprising an acquisition module, a processing module, and a control module.

[0100] The acquisition module is used to acquire coating images of lithium battery coating taken by the industrial camera 1.

[0101] The processing module is used to determine the amount of movement of the coating die head based on the coating image.

[0102] The control module is used to control the movement of the coating die head according to the amount of movement of the coating die head, so as to correct coating defects.

[0103] The processing module is used to perform grayscale processing on the coating image to obtain a grayscale image, perform binarization processing on the grayscale value of each pixel in the grayscale image according to a preset grayscale threshold to obtain a binarized image, process the binarized image to obtain the width of the coating defect, and determine the movement amount of the coating die head based on the width of the coating defect according to a preset unit movement amount.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

[0105] The system provided in the above embodiments is only illustrated by the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the modules or steps in the embodiments of the present invention can be further decomposed or combined. For example, the modules in the above embodiments can be merged into one module, or further divided into multiple sub-modules to complete all or part of the functions described above. The names of the modules and steps involved in the embodiments of the present invention are only for distinguishing the various modules or steps and are not considered as an improper limitation of the present invention.

[0106] Those skilled in the art will recognize that the modules and method steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. The programs corresponding to the software modules and method steps can be placed in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disks, removable disks, CD-ROMs, or any other form of storage medium known in the art. To clearly illustrate the interchangeability of electronic hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in electronic hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the invention.

Claims

1. A closed-loop method for correcting defects in lithium battery coating processes, characterized in that, An industrial camera and a linear light source are installed on the coating back roller; The method includes: Acquire coating images of lithium battery coating captured by the industrial camera; The coated image is converted to grayscale to obtain a grayscale image; The gray values ​​of each pixel in the grayscale image are binarized according to a preset grayscale threshold to obtain a binarized image. The width of the coating defect is obtained by processing the binarized image. Based on a preset unit movement amount, the movement amount of the coating die head is determined according to the width of the coating defect, and the movement of the coating die head is controlled according to the movement amount of the coating die head to correct the coating defect. The binarized image is processed to obtain the width of the coating defect, including: The substrate region is determined based on the binarized grayscale values ​​of the pixels in the binarized image; Obtain the width value of the substrate region, and determine the type of the substrate region based on the preset width value; If the width of the substrate region is equal to the preset width value, then the substrate region is an electrode region; If the width value of the substrate area is not equal to the preset width value, then the substrate area is a defective area; The width of the coating defect is determined based on the width value of the defect area; Determining the substrate region based on the binarized grayscale values ​​of the pixels in the binarized image includes: When the binarized gray value G0 of a pixel in the binarized image is 0, the pixel is defined as belonging to the substrate region. When the binarized gray value G0 of a pixel in the binarized image is 255, the pixel is defined as belonging to the coating area.

2. The closed-loop method for defect correction in lithium battery coating process according to claim 1, characterized in that, The industrial camera is positioned above the coating back roller, and the linear light source is positioned to the side of the coating back roller. The illumination point of the linear light source is the acquisition point of the industrial camera.

3. The closed-loop method for defect correction in lithium battery coating process according to claim 1, characterized in that, The coating image is an image containing the left electrode and the right electrode of the lithium battery.

4. The closed-loop method for defect correction in lithium battery coating process according to claim 1, characterized in that, Binarization processing is performed on the grayscale values ​​of each pixel in the grayscale image according to a preset grayscale threshold, including: Preset grayscale threshold g; Determine the grayscale value G of each pixel in the grayscale image; The grayscale threshold g is compared with the grayscale value G, and the binarized grayscale value G0 of each pixel in the grayscale image is determined according to the comparison result. When the gray value G ≥ gray threshold g, the binarized gray value G0 is 255; When the gray value G < gray threshold g, the binarized gray value G0 is 0.

5. The closed-loop method for defect correction in lithium battery coating process according to claim 1, characterized in that, The coating defects include missing foil in the middle and long scratches.

6. The closed-loop method for defect correction in lithium battery coating process according to claim 1, characterized in that, Before determining the movement amount of the coating die head based on the width of the coating defect, based on a preset unit movement amount, the method further includes: Obtain the historical movement of the coating die head and the corresponding change in coating width; Determine the ratio between the historical movement amount and the change in coating width, and determine the unit movement amount based on the ratio.

7. The closed-loop method for defect correction in lithium battery coating process according to claim 1, characterized in that, Based on a preset unit movement amount, the movement amount of the coating die head is determined according to the width of the coating defect, including: Determine the preset unit movement amount 'a' and the width of the coating defect 'b'; Determine the product between the unit movement amount a and the width b of the coating defect, and determine the movement amount c of the coating die head based on the product; The formula for calculating the movement amount c of the coating die head is: c = a b.

8. A closed-loop system for correcting defects in lithium battery coating processes, characterized in that, include: An industrial camera is positioned above the coating back roller and is used to capture coating images of lithium battery coating. A linear light source is disposed on the side of the coating back roller, and the illumination point of the linear light source is the acquisition point of the industrial camera; A correction closed-loop system, comprising an acquisition module, a processing module, and a control module; The acquisition module is used to acquire coating images of lithium battery coating captured by the industrial camera; The processing module is used to determine the amount of movement of the coating die head based on the coating image; The control module is used to control the movement of the coating die head according to the amount of movement of the coating die head, so as to correct coating defects; The processing module is used to perform grayscale processing on the coating image to obtain a grayscale image, perform binarization processing on the grayscale value of each pixel in the grayscale image according to a preset grayscale threshold to obtain a binarized image, process the binarized image to obtain the width of the coating defect, and determine the movement amount of the coating die head based on the width of the coating defect according to a preset unit movement amount.

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