Electrode sheet test method and system

Abstract

The embodiments of the present disclosure provide an electrode sheet test method and system, applicable to a camera system. The method comprises: before an electrode sheet is wound, obtaining a first image of a first surface of the electrode sheet and a second image of a second surface of the electrode sheet, the first image and the second image being acquired by an image acquisition element; on the basis of the first image, determining a size parameter of a test target on the first surface in the electrode sheet, and, on the basis of the second image, determining a size parameter of the test target on the second surface in the electrode sheet, the test target comprising at least a calibration block corresponding to the electrode sheet, and the calibration block being used for determining whether the image acquisition element has been offset; and, on the basis of the size parameter on the first surface and the size parameter on the second surface, determining a test result for the electrode sheet.

Description

Pole piece detection method and system

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure is based on the Chinese patent application with application number 202311484017.4, application date November 9, 2023, and invention name “Pole piece detection method and system”, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby introduced into this disclosure as a reference. Technical Field

[0003] The embodiments of the present disclosure relate to the technical field of battery detection, and are related to, but not limited to, a pole piece detection method and system. Background Art

[0004] New energy batteries are being used more and more widely in life and industry. For example, new energy vehicles equipped with batteries have been widely used. In addition, batteries are also being increasingly used in energy storage fields.

[0005] When detecting the alignment of the battery cell electrodes, the related technology uses a charge coupled device (CCD) camera to obtain the relative positions of the positive and negative electrode film areas before winding, thereby ensuring that the edges of the positive and negative electrodes are effectively aligned when the electrodes are wound.

[0006] However, since the edges of the positive electrode sheets have inorganic insulating materials, there is a certain degree of misalignment in the active areas on the front and back sides of the positive electrode sheets. The relevant technology only aligns the edges of the positive and negative electrode sheets, and cannot ensure that the active areas of the positive and negative electrode sheets are aligned.

[0007] Summary of the Invention

[0008] In order to solve the problems existing in the related technology, the embodiments of the present disclosure provide a pole piece detection method and system, which can effectively ensure that the negative pole piece covers the active area of ​​the positive pole piece, and reduce the problem of battery cells being unusable due to the alignment of the active area.

[0009] In a first aspect, the present disclosure provides a pole piece detection method, which is applied to a camera system, and the pole piece detection method includes: before the pole piece is wound, obtaining a first image of the first surface of the pole piece and a second image of the second surface of the pole piece captured by an image acquisition element; determining the size parameters of the detection target in the pole piece on the first surface based on the first image, and determining the size parameters of the detection target in the pole piece on the second surface based on the second image; the detection target includes at least a calibration block corresponding to the pole piece, and the calibration block is used to determine whether the image acquisition element is offset; based on the size parameters of the first surface and the size parameters of the second surface, determining the detection result of the pole piece.

[0010] In the above embodiment, by acquiring images of the first and second sides of the electrode, the size parameters of the detection target on the first and second sides of the electrode are determined, and based on the size parameters of the detection target on the first and second sides, the consistency of the detection targets on the front and back sides of the electrode is monitored, thereby reducing the problem of misalignment of the detection targets on the front and back sides of the electrode. In this way, on the basis of the alignment of the edges of the positive and negative electrodes, the alignment of the detection targets on the front and back sides of the electrode is guaranteed, so that when the electrode is wound, the negative electrode can cover the active area of ​​the positive electrode, thereby reducing the situation where the battery cell cannot be used due to the misalignment of the positive and negative detection targets, and more accurately monitoring the alignment of the positive and negative electrodes during winding, thereby ensuring the yield and safety of the battery cell.

[0011] In some embodiments, the detection target also includes the coating of the pole piece; the determining the size parameters of the detection target in the pole piece on the first surface according to the first image, and the determining the size parameters of the detection target in the pole piece on the second surface according to the second image, include: determining the coating width of the coating on the first surface according to the first image; determining the coating width of the coating on the second surface based on the second image; correspondingly, determining the detection result of the pole piece based on the size parameters of the first surface and the size parameters of the second surface, include: determining the coating width difference of the coating between the first surface and the second surface based on the coating width of the first surface and the coating width of the second surface; comparing the coating width difference with the target difference threshold to obtain the alignment result of the coating on the first surface and the second surface.

[0012] In some embodiments, the coating width difference is compared with a target difference threshold to obtain an alignment result of the coating on the first surface and the second surface, including: in response to the coating width difference being greater than or equal to the target difference threshold, generating a first alignment result indicating that the pole piece does not meet the alignment condition; in response to the coating width difference being less than the target difference threshold, generating a second alignment result indicating that the pole piece meets the alignment condition.

[0013] In the above embodiment, the detection targets of the front and back edges of the electrode are monitored for consistency, which reduces the problem of misalignment of the active areas on both sides of the electrode, thereby effectively ensuring that the negative electrode can cover the active area of ​​the positive electrode during the winding process, and reducing the yield problem of the battery cell caused by misalignment of the active areas.

[0014] In some embodiments, the image acquisition element includes a first image acquisition element for acquiring the first image and a second image acquisition element for acquiring the second image; determining the size parameters of the detection target in the pole piece on the first surface according to the first image, and determining the size parameters of the detection target in the pole piece on the second surface according to the second image, includes: determining the calibration width of the calibration block on the first surface according to the first image, and determining the calibration width of the calibration block on the second surface according to the second image; correspondingly, the method also includes: respectively determining the difference between the calibration width of the first surface, the calibration width of the second surface and the standard width of the calibration block to obtain a first calibration difference and a second calibration difference; respectively comparing the first calibration difference and the second calibration difference with the calibration difference threshold to obtain the offset result of the first image acquisition element and the offset result of the second image acquisition element.

[0015] In the above embodiment, before the electrode is inspected, the position of the image acquisition element in the camera system is corrected so that when the electrode is inspected, there will be no detection error due to the offset of the image acquisition element, resulting in inaccurate detection results, making it impossible for the electrode to be wound to enter the winding process, resulting in a low yield of the battery cell after winding, thereby improving the yield of the battery cell.

[0016] In some embodiments, determining the size parameters of the detection target in the pole piece on the first surface based on the first image, and determining the size parameters of the detection target in the pole piece on the second surface based on the second image, includes: determining the first defect on the first surface, the second defect on the second surface, the area of ​​the first defect, and the area of ​​the second defect based on the first image and the second image; correspondingly, determining the detection result of the pole piece based on the size parameters of the first surface and the size parameters of the second surface, includes: in response to the area of ​​the first defect and / or the area of ​​the second defect being greater than a defect area threshold, generating a detection result that the pole piece has a defect; in response to the area of ​​the first defect and the area of ​​the second defect being less than or equal to a defect area threshold, generating a detection result that the pole piece can be wound.

[0017] In the above embodiment, defects on both sides of the electrode are detected, which reduces the number of defective electrode sheets entering the winding process, ensures that the battery cells are produced from qualified materials, and improves the yield of the battery cells.

[0018] In some embodiments, the method further includes: determining the vertical distance between the pole piece boundary and the reference point based on the first image or the second image; and generating a pole piece offset result of the pole piece offset in the pole piece transmission direction in response to the difference between the vertical distance and the standard distance being greater than a distance threshold.

[0019] In the above embodiment, before the electrode enters the winding process, not only the alignment of the active areas on both sides of the electrode is detected, but also the moving direction of the electrode is detected, which reduces the problem of unqualified alignment of the positive and negative electrode sheets due to lateral displacement of the electrode during transmission, and improves the yield of the battery cell winding.

[0020] In some embodiments, the acquiring of the first image of the first surface of the pole piece and the second image of the second surface of the pole piece acquired by the image acquisition element includes: in response to a trigger signal sent by a controller, acquiring the first image of the first surface of the pole piece and the second image of the second surface of the pole piece acquired by the image acquisition element; the pole piece detection method also includes: sending the detection result of the pole piece to the controller.

[0021] In a second aspect, the present disclosure provides a pole piece detection system, which includes at least a camera system, and the camera system includes: an image acquisition element, which is used to capture a first image of the first surface of the pole piece and a second image of the second surface of the pole piece before the pole piece is wound; a processor, connected to the image acquisition element, and the processor is used to determine the size parameters of the detection target in the pole piece on the first surface based on the first image, and to determine the size parameters of the detection target in the pole piece on the second surface based on the second image; the detection target includes at least a calibration block corresponding to the pole piece, and the calibration block is used to determine whether the image acquisition element is offset; based on the size parameters of the first surface and the size parameters of the second surface, the detection result of the pole piece is determined.

[0022] In the above embodiment, the electrode detection system determines the size parameters of the detection target on the first and second sides of the electrode by acquiring images of the first and second sides of the electrode, and monitors the consistency of the detection targets on the front and back sides of the electrode based on the size parameters of the detection targets on the first and second sides, thereby reducing the problem of misalignment of the detection targets on the front and back sides of the electrode. In this way, on the basis of the alignment of the edges of the positive and negative electrodes, the alignment of the detection targets on the front and back sides of the electrode is guaranteed, so that when the electrode is wound, the situation where the battery cell cannot be used due to the misalignment of the positive and negative detection targets is reduced, and the alignment of the positive and negative electrodes during winding is monitored more accurately, thereby ensuring the yield and safety of the battery cell.

[0023] In some embodiments, the pole piece detection system further includes: a mounting frame for mounting a first image acquisition element and a second image acquisition element; in a transmission direction perpendicular to the pole piece, the first image acquisition element and the second image acquisition element are respectively arranged on both sides of the pole piece; a first light source and a second light source provide illumination for the pole piece; a first bracket is arranged between the first image acquisition element and the first surface; a second bracket is arranged between the second image acquisition element and the second surface; the field of view hole of the first bracket corresponds to the field of view hole on the second bracket, and the first image acquisition element and the second image acquisition element acquire the first image and the second image of the pole piece through the field of view hole.

[0024] In the above embodiment, light sources are respectively provided at the two image acquisition elements to illuminate the pole piece field of view in the field of view hole, thereby ensuring uniform brightness of the camera imaging, improving the imaging quality, and reducing false detection and missed detection.

[0025] In some embodiments, the pole piece detection system further includes: calibration blocks respectively provided on the first bracket and the second bracket.

[0026] In the above embodiment, the processor can determine the size parameters of the detection target and the size of the defect on the pole piece based on the calibration block, thereby improving the detection accuracy.

[0027] In some embodiments, the pole piece detection system also includes: a controller, which is electrically connected to the processor and is used to send a trigger signal to the camera system in response to the pole piece winding machine starting to work; receive the pole piece detection results sent by the camera system, and send the pole piece detection results to the pole piece winding machine; the pole piece winding machine is electrically connected to the controller and is used to perform one of the following processing on the pole piece in response to the detection results: winding, re-inspection and scrapping.

[0028] The above description is only an overview of the technical solution of the present disclosure. In order to more clearly understand the technical means of the present disclosure, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present disclosure more obvious and easy to understand, the specific implementation methods of the present disclosure are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG1 is a schematic diagram of an optional flow chart of a pole piece detection method provided in an embodiment of the present disclosure;

[0030] FIG2 is a schematic diagram of a pole piece moving process provided by an embodiment of the present disclosure;

[0031] FIG3 is a first structural diagram of a pole piece detection system provided by an embodiment of the present disclosure;

[0032] FIG4 is a second structural diagram of a pole piece detection system provided by an embodiment of the present disclosure;

[0033] FIG5 is a third structural diagram of a pole piece detection system provided by an embodiment of the present disclosure;

[0034] FIG6 is a schematic diagram of the edge detection principle provided by an embodiment of the present disclosure;

[0035] FIG7 is a schematic flow chart of a method for detecting an edge of a pole piece according to an embodiment of the present disclosure;

[0036] FIG8 is a flow chart of a camera detection method provided in an embodiment of the present disclosure.

[0037] Explanation of the accompanying reference numerals: 201-pole to be detected; 2011-target to be detected; L-width of the detection target; 301-camera system; 3011-image acquisition element; 3012-processor; 302-pole; 3021-detection target; 401-mounting frame; 402-first light source; 403-second light source; 404-first bracket; 405-second bracket; 406-first image acquisition element; 407-second image acquisition element; 408-field of view; 409-calibration block; 501-L-shaped bracket; 502-camera; 503-calibration block structure; 504-light source; 505-hard reference bracket; 506-bracket field of view hole; 601-positive electrode; 6011-inorganic insulating layer; 602-acquisition camera; 603-algorithm frame capture. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the present disclosure clearer, the present disclosure will be further described in detail below with reference to the accompanying drawings. The described embodiments should not be regarded as limiting the present disclosure. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present disclosure.

[0039] In the following description, references to "some embodiments" describe a subset of all possible embodiments, but it is understood that "some embodiments" can be the same subset or different subsets of all possible embodiments, and can be combined with each other without conflict. Unless otherwise defined, all technical and scientific terms used in the embodiments of the present disclosure have the same meaning as commonly understood by those skilled in the art to which the embodiments of the present disclosure belong. The terms used in the embodiments of the present disclosure are only for the purpose of describing the embodiments of the present disclosure and are not intended to limit the present disclosure.

[0040] Currently, new energy batteries are increasingly being used in everyday life and industry. They are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric cars, as well as in a variety of fields such as aerospace. As the application of power batteries continues to expand, market demand is also growing.

[0041] In the embodiments of the present disclosure, the battery may be a battery cell (sometimes also referred to as a battery cell), or a battery module or battery pack comprising a plurality of battery cells. A battery cell refers to a basic unit that can realize the mutual conversion of chemical energy and electrical energy, and can be used to make a battery module or battery pack, thereby being used to supply power to electrical devices. A battery cell may be a secondary battery, which refers to a battery cell that can be activated by charging the active material after the battery cell is discharged and can continue to be used. The battery cell may be a lithium-ion battery, a sodium-ion battery, a sodium-lithium-ion battery, a lithium metal battery, a sodium metal battery, a lithium-sulfur battery, a magnesium-ion battery, a nickel-hydrogen battery, a nickel-cadmium battery, a lead-acid battery, etc., and the embodiments of the present disclosure are not limited thereto.

[0042] During the wound battery production process, the laser-cut electrode sheets are rolled into a core-like structure using a winding needle. Typically, the layers are stacked in the order of separator, positive electrode, separator, and negative electrode, forming a wound cell. The separator and electrode sheets are wound together to form the battery cell. The separator separates the positive and negative electrodes, preventing internal short circuits in the battery while allowing the free passage of electrolyte ions, completing the electrochemical charge and discharge process.

[0043] In order to form a qualified battery cell during winding, the active areas of the positive and negative electrodes need to be aligned before winding to form a qualified battery cell. The related technology only uses a CCD camera to obtain the relative position of the positive and negative electrode film areas, so as to ensure that the edges of the positive and negative electrodes are effectively aligned when the electrodes are wound. However, since metal burrs are prone to appear on the edges of the positive electrode sheets of lithium batteries after die-cutting, when the burrs pierce the diaphragm, they will directly conduct with the negative electrode sheet, which may cause the risk of lithium battery fire and explosion. Therefore, in order to reduce such problems, a layer of 1 to 3 mm (mm) wide inorganic insulating material will be coated on the edge of the positive electrode sheet. Due to errors in the coating process, there may be a certain degree of misalignment in the active areas on the front and back of the positive electrode sheet, resulting in unqualified alignment of the front and back active areas of the positive and negative electrode sheets, and thus the failure to produce qualified battery cells.

[0044] In order to solve the problem of unqualified alignment of the front and back active areas of the positive and negative electrode sheets during the winding process, the present inventors conducted in-depth research and found that the active areas on both sides of the positive electrode sheet can be monitored before winding. If the active areas on both sides of the positive electrode sheet are misaligned, the sheet is processed and the sheet with the misalignment problem is not entered into the winding process, so as to reduce the problem of insufficient performance of the battery cell after winding.

[0045] Based on the above considerations, an embodiment of the present disclosure provides a pole piece detection method, which obtains images of the first side and the second side of the pole piece captured by the image acquisition element, determines the size parameters of the detection target of the pole piece on the first side and the second side, and monitors the consistency of the detection targets on the front and back sides of the pole piece based on the size parameters of the detection targets on the first side and the second side, thereby reducing the problem of misalignment of the detection targets on the front and back sides of the pole piece. In this way, on the basis of the alignment of the edges of the positive and negative pole pieces, the alignment of the detection targets on the front and back sides of the pole piece is guaranteed, so that when the pole piece is wound, the situation where the battery cell cannot be used due to the misalignment of the positive and negative detection targets is reduced, and the alignment of the positive and negative pole pieces during winding is monitored more accurately, thereby ensuring the yield and safety of the battery cell.

[0046] The electrode detection method provided in the embodiment of the present disclosure is applied before the positive and negative electrode sheets are wound to form a battery cell. The electrode detection method is implemented by a electrode detection system that includes at least a camera system. The electrode detection method provided in the embodiment of the present disclosure is implemented with the camera system in the electrode detection system as the execution subject.

[0047] FIG1 is an optional flow chart of a pole piece detection method provided by an embodiment of the present disclosure. As shown in FIG1 , the pole piece detection method provided by an embodiment of the present disclosure can be implemented through steps S101 to S103:

[0048] Step S101: Before the pole piece is wound, a first image of the first surface of the pole piece and a second image of the second surface of the pole piece are acquired by an image acquisition component.

[0049] The pole piece detection method provided in the embodiment of the present disclosure is applied to the traveling pole piece before the pole piece is wound, that is, before the pole piece enters the winding station. The embodiment of the present disclosure implements the pole piece detection method through a camera system in the pole piece detection system. The camera system includes at least an image acquisition element and a processor. The image acquisition element may be a CCD camera. The processor is connected to the image acquisition element. The image acquisition element is used to capture images of the first side and the second side of the pole piece. The processor stores a memory of processor-executable instructions. When the instructions are executed by the processor, the pole piece detection method provided in the embodiment of the present disclosure is implemented.

[0050] In some embodiments, the pole piece detection system further includes a controller connected to the camera system. The controller can be a programmable logic controller (PLC), an intermediate computer, a host computer, and a single-chip microcomputer. In response to a pole piece detection operation on the controller, the camera system uses an image acquisition element to capture images of the first surface and the second surface of the pole piece to obtain a first image and a second image.

[0051] In some embodiments, the image acquisition element may acquire images of the first and second surfaces of the pole piece in real time, or may acquire images once at intervals, for example, the first image and the second image may be acquired once every 5 seconds, so as to obtain multiple first images and multiple second images of the pole piece as it moves.

[0052] In some embodiments, the electrode may refer to the positive electrode and the negative electrode of the battery, wherein the edge of the positive electrode has an insulating coating. Pole piece inspection on both sides of the positive electrode can determine whether there is misalignment in the active areas on both sides of the positive electrode, and pole piece inspection on both sides of the negative electrode can determine whether the negative electrode has defects.

[0053] Step S102: determining the size parameters of the detection target in the pole piece on the first surface based on the first image, and determining the size parameters of the detection target in the pole piece on the second surface based on the second image; the detection target includes at least a calibration block corresponding to the pole piece, and the calibration block is used to determine whether the image acquisition element is offset.

[0054] In some embodiments, the detection target includes at least a coating on the first and second surfaces of the electrode, and the coating may refer to an insulating area on the edges of the first and second surfaces of the electrode. Determining the size parameters of the detection target may refer to detecting the width of the insulating area. The width direction of the insulating area is perpendicular to the moving direction of the electrode. Figure 2 is a schematic diagram of the electrode moving process provided by an embodiment of the present disclosure. As shown in Figure 2, the figure shows an image of one of the surfaces of the electrode to be detected. The electrode to be detected 201 moves along the direction A. The electrode to be detected 201 has a target to be detected 2011 on it. Based on the image, the size parameters of the target to be detected 2011, that is, the width L of the detection target, can be determined.

[0055] In some embodiments, the detection target may also be a defect on the pole piece, and the size parameters of the defect on the pole piece are determined through the image to determine whether the pole piece can be wound.

[0056] Here, determining the size parameters of the detection target based on the image may be implemented by a processor of the camera system, where the processor recognizes the first image and the second image and determines the size parameters of the detection target on the first surface and the second surface respectively.

[0057] In some embodiments, the first surface and the second surface of the pole piece can respectively correspond to a fixed calibration block, and the calibration blocks on the two surfaces are the same size. When the image acquisition element acquires images of the first surface and the second surface, it can determine whether the image acquisition element has been offset based on whether the calibration blocks in the two images are deformed, so as to ensure the accuracy of the image acquisition element in acquiring the image and improve the detection accuracy.

[0058] Step S103: Determine a detection result of the pole piece based on the size parameters of the first surface and the size parameters of the second surface.

[0059] In some embodiments, when the detection target is the width of the insulating coating, the detection result of the electrode can be determined based on the comparison of the widths of the coating on the two surfaces. For example, if the difference between the width of the coating on the first surface and the width of the coating on the second surface is large, it means that the misalignment of the active areas on the two surfaces of the electrode is large. When the electrode enters the winding, the active areas of the positive and negative electrodes cannot be aligned. Therefore, the detection result is that the electrode does not meet the alignment conditions; if the difference between the width of the coating on the first surface and the width of the coating on the second surface is small, it means that the misalignment of the active areas on the two surfaces of the electrode is within the error range. When the electrode enters the winding, the active areas of the positive and negative electrodes will not be unable to be aligned. Therefore, the detection result is that the electrode meets the alignment conditions.

[0060] In some embodiments, when the detection target is a defect on a pole piece, whether the pole piece can be wound is determined based on the size parameters of the defect. For example, when the size of the defect on the pole piece is smaller than a defect threshold size, the detection result is that the pole piece can be wound; when the size of the defect on the pole piece is larger than the defect threshold size, the detection result is that the pole piece cannot be wound.

[0061] The disclosed embodiment provides a pole piece detection method, which obtains images of the first side and the second side of the pole piece, determines the size parameters of the detection target of the pole piece on the first side and the second side, and monitors the consistency of the detection targets on the front and back sides of the pole piece based on the size parameters of the detection targets on the first side and the second side, thereby reducing the problem of misalignment of the detection targets on the front and back sides of the pole piece. In this way, on the basis of the alignment of the edges of the positive and negative pole pieces, the alignment of the detection targets on the front and back sides of the pole piece is guaranteed, so that when the pole piece is wound, the negative pole piece can cover the active area of ​​the positive pole piece, thereby reducing the situation where the battery cell cannot be used due to the misalignment of the positive and negative detection targets, and more accurately monitors the alignment of the positive and negative pole pieces during winding, thereby ensuring the yield and safety of the battery cell.

[0062] In some embodiments, the detection target also includes the coating on the first and second surfaces of the electrode. The coating can refer to the insulating area on the edges of the first and second surfaces of the electrode, that is, the insulating area is detected. If the widths of the insulating areas on both sides are the same, the electrode can enter the winding process. The coating can also refer to the active area on the first and second surfaces of the electrode. If the widths of the active areas are the same and the distances between the active areas on both sides and the edges are the same, the electrode can enter the winding process. Based on the above embodiment, step S102 can be implemented through steps S1021 to S1022:

[0063] Step S1021: Determine the coating width of the coating on the first surface according to the first image.

[0064] Step S1022: Determine the coating width of the coating on the second surface based on the second image.

[0065] In the embodiment of the present disclosure, the processor may determine the coating width on the first side and the second side by identifying the first image and the second image.

[0066] Correspondingly, step S103 can be implemented through steps S1031 to S1032:

[0067] Step S1031 : determining a coating width difference between the first surface and the second surface based on the coating width on the first surface and the coating width on the second surface.

[0068] In some implementations, the coating width difference refers to the difference in coating widths on the two surfaces of the electrode, which is used to indicate whether the coatings on the two surfaces are misaligned, and further to indicate whether the active areas on the two surfaces of the electrode are misaligned.

[0069] Step S1032: Compare the coating width difference with a target difference threshold to obtain alignment results of the coating on the first surface and the second surface.

[0070] In some embodiments, the target difference threshold can be set by a technician and can be 0.2 millimeters (mm). In response to the coating width difference being greater than or equal to the target difference threshold, a first alignment result is generated indicating that the electrode piece does not meet the alignment condition, wherein the alignment condition is that the coating width difference is less than the target difference threshold; when the coating width difference is less than the target difference threshold, a second alignment result is generated indicating that the electrode piece meets the alignment condition.

[0071] The disclosed embodiment monitors the consistency of detection targets at the front and back edges of the electrode sheet, reducing the problem of misalignment of active areas on both sides of the electrode sheet, thereby effectively ensuring that the negative electrode sheet can cover the active area of ​​the positive electrode sheet during the winding process, and reducing the yield problem of the battery cell caused by misalignment of the active areas.

[0072] In some embodiments, the image acquisition element in the camera system includes a first image acquisition element for acquiring images of the first surface of the electrode piece and a second image acquisition element for acquiring images of the second surface of the electrode piece. The first surface and the second surface of the electrode piece respectively correspond to a fixed calibration block, and the calibration blocks on the two surfaces are the same size. The calibration blocks are used to calculate the coating width on the first surface and the second surface of the electrode piece. Based on the above embodiment, step S102 can also be implemented by step S1:

[0073] Step S1: determining a calibration width of the calibration block on a first surface according to the first image, and determining a calibration width of the calibration block on a second surface according to the second image.

[0074] In some embodiments, the electrode detection system further includes a mounting frame for mounting image acquisition components, the image acquisition components including a first image acquisition component for capturing images of the first surface and a second image acquisition component for capturing images of the second surface. The mounting frame is provided with a first bracket and a second bracket, the first bracket being provided between the first image acquisition component and the first surface, and the second bracket being provided between the second image acquisition component and the second surface. Identical calibration blocks are provided on the first bracket and the second bracket, the calibration blocks being respectively located between the brackets and the image acquisition components. The calibration blocks may be cubes with a length, width, and height of 1 mm each, and may be used to calibrate whether the first image acquisition component and the second image acquisition component are offset on the mounting frame.

[0075] In the disclosed embodiment, the direction of the calibrated width may also be perpendicular to the direction of travel of the pole piece. When acquiring the first image and the second image, the image containing the calibration block is acquired, and the processor recognizes the first image and the second image respectively to obtain the calibrated width of the calibration block on the first image and the calibrated width of the calibration block on the second image.

[0076] Correspondingly, since the calibration blocks corresponding to the two sides of the electrode are the same, before detecting the coating widths on both sides of the electrode, it is possible to determine whether the two image acquisition components are offset by measuring the calibration widths of the calibration blocks in the first image and the second image captured by the two image acquisition components. The electrode detection method provided in the embodiment of the present disclosure also includes steps S2 and S3:

[0077] Step S2: respectively determining the differences between the calibrated width of the first surface, the calibrated width of the second surface, and the standard width of the calibration block to obtain a first calibration difference and a second calibration difference.

[0078] In some embodiments, the standard width of the calibration block is fixed, for example, 1 mm. After determining the calibrated width of the calibration block on the first side and the calibrated width of the second side, a first calibrated difference between the calibrated width of the first side and the standard width and a second calibrated difference between the calibrated width of the second side and the standard width can be determined.

[0079] Step S3: Compare the first calibration difference value, the second calibration difference value and a calibration difference threshold value respectively to obtain an offset result of the first image acquisition component and an offset result of the second image acquisition component.

[0080] In some embodiments, the calibration difference threshold can also be set by a technician, for example, 0.1 mm. The first calibration difference is compared with the calibration difference threshold. If the first calibration difference is less than the calibration difference threshold, it indicates that the offset of the first image acquisition element is within the error range. This offset will not cause a large error when identifying the size parameters of the detection target, resulting in an offset result that the first image acquisition element meets the offset condition. If the first calibration difference is greater than or equal to the calibration difference threshold, it indicates that the offset of the first image acquisition element is large. This offset will cause a large error when identifying the size parameters of the detection target, resulting in an offset result that the first image acquisition element does not meet the offset condition. At this time, the camera system will issue a prompt, prompting the engineer to correct the position of the first image acquisition element until the first calibration difference is less than the calibration difference threshold.

[0081] In some embodiments, the offset result of determining the second image acquisition element is the same as that of the first image acquisition element, and is not described again here.

[0082] The disclosed embodiment corrects the position of the image acquisition element in the camera system before inspecting the electrode, so that when inspecting the electrode, there will be no detection error due to the offset of the image acquisition element, which will lead to inaccurate detection results, making it impossible for the electrode to enter the winding process, resulting in a low yield of the battery cell after winding, thereby improving the yield of the battery cell.

[0083] In some embodiments, it is also possible to determine whether there are defects such as wrinkles or damage on the electrode piece through the collected first image and the second image, and determine whether the electrode piece can be wound based on the detection result. Based on the above embodiment, step S102 can also be implemented through step S4:

[0084] Step S4: Determine a first defect on the first surface of the electrode, a second defect on the second surface of the electrode, an area of ​​the first defect, and an area of ​​the second defect based on the first image and the second image.

[0085] In some embodiments, the processor identifies the first image and the second image to determine the defects and the area of ​​the defects on the first and second surfaces of the pole piece. The area can be determined by the pixel points of the defects on the image.

[0086] Correspondingly, step S103 can also be implemented through steps S5 and S6:

[0087] Step S5: In response to the area of ​​the first defect and / or the area of ​​the second defect being greater than a defect area threshold, generating a detection result indicating that the pole piece has a defect.

[0088] Step S6: In response to the fact that the area of ​​the first defect and the area of ​​the second defect are both smaller than or equal to a defect area threshold, generating a detection result indicating that the pole piece can be wound.

[0089] In the embodiment of the present disclosure, the defect area threshold can be set by a technician, for example, the defect area threshold is 1 square millimeter. Each surface of the electrode may include at least one defect. If the area of ​​at least one of the first defect on the first surface of the electrode or the second defect on the second surface is greater than the defect area threshold, it indicates that the electrode has a defect, and the processor generates a detection result that the electrode has a defect. If the area of ​​the first defect on the first surface of the electrode and the area of ​​the second defect on the second surface are both less than or equal to the defect area threshold, it indicates that the defect on the electrode is within the error range, and the electrode can be used in the battery cell after winding. At this time, the processor generates a detection result that the electrode can be wound.

[0090] The disclosed embodiment detects defects on both sides of the electrode, reduces defective electrodes from entering the winding process, ensures that the battery cells are produced from qualified materials, and improves the yield of the battery cells.

[0091] In some embodiments, the first image and the second image collected can also be used to determine whether the pole piece has shifted during the process of traveling. If the offset exceeds the offset threshold, the positive and negative pole pieces cannot be aligned during winding, and the shifted pole piece needs to be processed. Based on the above embodiment, the pole piece detection method provided in the embodiment of the present disclosure also includes steps S7 and S8:

[0092] Step S7: Determine the vertical distance between the pole piece boundary and the reference point according to the first image or the second image.

[0093] In some embodiments, the reference point can be a fixed point on the mounting frame, and the reference point is used to measure whether the pole piece has undergone lateral displacement during its movement. If the distance between the boundary of the pole piece and the reference point does not change during its movement, it indicates that the pole piece has not undergone lateral displacement during its movement.

[0094] The first image or the second image acquired by the processor has the reference point, and the vertical distance can be obtained by the processor by identifying one of the first image or the second image.

[0095] Step S8: In response to the difference between the vertical distance and the standard distance being greater than a distance threshold, a pole piece offset result of the pole piece offset in the pole piece transmission direction is generated.

[0096] Here, the standard distance may refer to the vertical distance between the pole piece boundary and the reference point when the pole piece is not offset. Since the first image or the second image is acquired by the image acquisition element in real time or at intervals, the processor determines the vertical distance between the pole piece boundary and the reference point in real time or at intervals, and determines the lateral offset value of the pole piece during its movement based on the vertical distance and the standard distance, that is, the difference between the vertical distance and the standard distance, and compares the difference with a preset distance threshold to determine the pole piece offset result in the pole piece transmission direction (that is, the pole piece movement direction).

[0097] In some embodiments, the pre-set distance threshold can be 0.5mm. When the difference is less than 0.5mm, it means that the lateral offset of the pole piece is within the error range; when the difference is greater than or equal to 0.5mm, it means that the lateral offset of the pole piece is large. At this time, the equipment needs to be debugged to adjust the direction of movement of the pole piece.

[0098] Before the electrode enters the winding process, the embodiment of the present disclosure not only detects the alignment of the active areas on both sides of the electrode, but also detects the moving direction of the electrode, thereby reducing the problem of unqualified alignment of the positive and negative electrode sheets due to lateral offset of the electrode during transmission, and improving the yield rate of battery cell winding.

[0099] In some embodiments, the camera system captures images of both sides of the electrode based on a trigger signal from a controller in the electrode detection system. After inspecting the electrode using the electrode inspection method provided in the embodiments of the present disclosure, the camera system sends the inspection results to the controller. The controller herein may be a PLC, an intermediate computer, a host computer, or a single-chip microcomputer.

[0100] Next, the present disclosure provides a pole piece detection system for executing the above-mentioned pole piece detection method. FIG3 is a schematic structural diagram of the pole piece detection system provided by an embodiment of the present disclosure. As shown in FIG3 , the pole piece detection system includes at least a camera system 301. The camera system 301 includes an image acquisition element 3011 and a processor 3012. The image acquisition element 3011 is used to capture a first image of the first surface of the pole piece 302 and a second image of the second surface of the pole piece 302 before the pole piece 302 is wound; the processor 3012 is connected to the image acquisition element 3011, and the processor 3012 is used to obtain the first image of the first surface and the second image of the second surface of the pole piece 302, determine the size parameters of the detection target 3021 in the pole piece 302 on the first surface according to the first image, and determine the size parameters of the detection target 3021 in the pole piece 302 on the second surface according to the second image; and determine the detection result of the pole piece 302 based on the size parameters of the first surface and the size parameters of the second surface.

[0101] In the embodiment of the present disclosure, the image acquisition element may be a CCD camera.

[0102] Based on the aforementioned embodiment, FIG4 is a schematic structural diagram of a pole piece detection system provided by an embodiment of the present disclosure. As shown in FIG4 , the pole piece detection system further includes a mounting frame 401, a first light source 402, a second light source 403, a first bracket 404, and a second bracket 405. The image acquisition component is divided into a first image acquisition component 406 and a second image acquisition component 407.

[0103] Mounting frame 401 is used to mount a first image acquisition component 406 and a second image acquisition component 407. In a transmission direction B perpendicular to pole piece 302, first image acquisition component 406 and second image acquisition component 407 are respectively disposed on either side of pole piece 302 to capture a first image of the first surface and a second image of the second surface of pole piece 302, respectively.

[0104] The first light source 402 and the second light source 403 are arranged on the mounting frame 401. The first light source 402 is arranged on one side of the first image acquisition component 406 on the mounting frame 401 to provide light for the acquisition electrode 302 of the first image acquisition component 406; the second light source 403 is arranged on one side of the second image acquisition component 407 on the mounting frame 401 to provide light for the acquisition electrode 302 of the second image acquisition component 407.

[0105] A first bracket 404 is disposed between the first image acquisition element 406 and the first surface of the pole piece 302; a second bracket 405 is disposed between the second image acquisition element 407 and the second surface of the pole piece 302. The first bracket 404 and the second bracket 405 each have a viewing aperture 408. The viewing aperture 408 of the first bracket 404 corresponds to the viewing aperture 408 of the second bracket 405, meaning that the projections of the two viewing apertures 408 overlap in a direction perpendicular to the pole piece 302.

[0106] In the embodiment of the present disclosure, the first image acquisition element 406 and the second image acquisition element 407 acquire the first image and the second image by acquiring the image of the pole piece 302 through the field of view hole 408 .

[0107] 4 , the pole piece inspection system further includes a calibration block 409, which is disposed on the first bracket 404 and the second bracket 405. The calibration block 409 is used to provide a standard distance so that the processor can determine the size parameters of the inspection target and the size of the defect on the pole piece based on the calibration block 409.

[0108] In some embodiments, the pole piece detection system further includes a controller and a pole piece winding machine.

[0109] The controller is electrically connected to the processor and is configured to send a trigger signal to the camera system in response to the pole piece winding machine starting to work, so that the camera system executes the pole piece detection method and obtains a detection result; the controller is also configured to receive the pole piece detection result sent by the camera system, and send the pole piece detection result to the pole piece winding machine;

[0110] The pole piece winding machine is electrically connected to the controller and is used to perform one of the following operations on the pole piece in response to the test results: winding, re-inspection, and scrapping. Here, if the test result of the pole piece meets the winding conditions, the pole piece winding machine will wind the pole piece; if the test result shows that the pole piece needs to be re-inspected, the pole piece winding machine will send the pole piece to the X-ray equipment for re-inspection; if the test result shows that the pole piece has a large defect and does not meet the winding conditions and does not need to be re-inspected, the pole piece winding machine will scrap the pole piece.

[0111] The electrode inspection system provided by the disclosed embodiments can, firstly, monitor inspection targets on both sides of the electrode, significantly eliminating interference from the inorganic insulating layer at the electrode edge, more accurately monitoring the alignment of the positive and negative electrode sheets and ensuring battery cell safety. Secondly, the calibration block monitors camera accuracy, ensuring the normal operation of equipment during production and effectively reducing false detections and missed detections by the electrode inspection system.

[0112] The following describes an exemplary application of the embodiments of the present disclosure in a practical application scenario.

[0113] The electrode alignment detection method based on related technologies only obtains the relative position of the positive and negative electrode film areas before the electrode is wound, thereby ensuring the effective alignment of the positive and negative electrodes. However, due to the 1 to 3 mm wide inorganic isolation material at the edge of the positive electrode, there is a certain degree of misalignment in the active areas on the front and back of the electrode, resulting in unqualified (Not Good, NG) alignment of the positive and negative active areas. In addition, the electrode winding machine has been in production for a long time, and due to loose screws or accidental contact by personnel, the camera becomes loose, resulting in detection distortion, false detection and missed detection.

[0114] An embodiment of the present disclosure provides a detection system. Figure 5 is a structural schematic diagram of the pole piece detection system provided by an embodiment of the present disclosure. As shown in Figure 5, the detection system includes at least an L-shaped bracket 501, a camera 502, a calibration block structure 503, a light source 504, a hard reference bracket 505 and a bracket field of view hole 506.

[0115] Among them, the L-shaped bracket 501 is fixed on the pole piece transport station before the pole piece winding machine station. The camera 502, the calibration block structure 503 and the light source 504 are fixed on the L-shaped bracket 501, and the camera 502 is fixed at a position 70 mm away from the pole piece. On the L-shaped bracket 501, a camera 502 is installed on the front and back sides of the pole piece respectively to take images of the positive pole piece side. A hard reference bracket 505 is installed between the camera 502 and the pole piece, and the lens collects the pole piece image through the bracket field hole 506 on the hard reference bracket 505. The bracket field hole 506 is provided with a calibration block structure 503. The two light sources 504 are respectively located behind the camera 502, respectively illuminating the pole piece field of view in the bracket field hole 506, to ensure that the imaging brightness of the camera 502 is uniform and consistent, and to reduce false detection and missed detection.

[0116] The embodiment of the present disclosure provides a method for detecting a pole piece, in which the inorganic insulating layer (i.e., the detection target) at the edge of the positive pole piece is photographed by the front and back cameras of the pole piece detection system to ensure that the dislocation of the film area on the front and back of the pole piece is within the qualified range. Figure 6 is a schematic diagram of the edge detection principle provided by the embodiment of the present disclosure. As shown in Figure 6, during the winding process of the battery cell, the alignment information of the inorganic insulating layer 6011 on the front and back of the edge of the positive pole piece 601 is captured in real time by the acquisition camera 602, and the distance L (width) between the boundary edge and the outer edge of the inorganic insulating layer 6011 and the film area is calculated by the algorithm capture frame 603. Comparing the width difference |Δ1︱ of the inorganic insulating layer 6011 on the front and back of the positive pole piece 601, when |Δ1︱<0.2mm, the pole piece enters the pole piece winding machine for production normally; when |Δ1︱≥0.2mm, it is regarded as a pole piece NG. When the electrode meets the alignment specifications, it enters the electrode winding machine and the wound battery cell flows out normally. If it does not meet the alignment specifications, it will be scrapped or marked and sent to X-Ray (i.e. X-ray equipment) for re-inspection.

[0117] FIG7 is a flow chart of a method for detecting an edge of a pole piece provided by an embodiment of the present disclosure. As shown in FIG7 , the method for detecting an edge of a pole piece is implemented through steps S701 to S704:

[0118] Step S701: The camera captures images of the front and back of the electrode.

[0119] After the camera captures the front and back images of the electrode piece, the width of the inorganic insulating layer on the front and back images of the electrode piece is identified to obtain the width difference of the inorganic insulating layer on the front and back sides.

[0120] Step S702: Determine whether the width difference is less than a difference threshold.

[0121] In the embodiment of the present disclosure, if the width difference is less than or equal to the difference threshold, step S703 is executed; if the width difference is greater than the difference threshold, step S704 is executed.

[0122] Step S703: The electrode enters the electrode winding machine and is pulled normally.

[0123] In the embodiment of the present disclosure, if the width difference is less than or equal to the difference threshold, the pole piece enters the pole piece winding machine and is pulled normally.

[0124] Step S704: The electrode is scrapped.

[0125] In the embodiment of the present disclosure, if the width difference is greater than the difference threshold, the pole piece is scrapped.

[0126] In the embodiment of the present disclosure, when the production winding needle of the machine rotates, a pulse signal is sent through the PLC to trigger the camera to take pictures, ensuring that the camera works in real time to collect pictures during the movement of the positive electrode. The picture is passed through the region of interest (ROI) frame edge capture algorithm to calculate and determine whether the width difference between the front and back sides of the inorganic insulating layer |Δ1︱ is less than the difference threshold, and the electrode is divided into OK or NG, and the information is transmitted to the electrode winding machine through the PLC to execute product scrapping and re-inspection.

[0127] In the embodiment of the present disclosure, referring to FIG5 , a standard part with a standard width of 1 mm (i.e., calibration block structure 503) is added in the center of the field of view. The calibration block structure 503 serves as a real-time monitor of the accuracy (precision) of the camera. When the difference between the width of the calibration block in the image and 1 mm |Δ2︱≤0.1 mm, the pole piece enters the pole piece winding machine for production normally; when |Δ2︱>0.1 mm, the equipment alarm is shut down, prompting the engineer to maintain the camera.

[0128] FIG8 is a flow chart of a camera detection method provided by an embodiment of the present disclosure. As shown in FIG8 , the camera detection method is implemented through steps S801 to S805:

[0129] Step S801: The camera captures an image with a calibration block structure.

[0130] In response to the camera detection operation of the controller, the camera acquires an image having a calibration block structure.

[0131] Step S802: Determine whether the difference between the width of the calibration block structure in the image and the standard width is less than a calibration threshold.

[0132] In an embodiment of the present disclosure, if the difference between the width of the calibration block structure in the image and the standard width is less than or equal to the calibration threshold, step S803 is executed; if the difference between the width of the calibration block structure in the image and the standard width is greater than the calibration threshold, step S804 is executed.

[0133] Step S803: normal production.

[0134] In an embodiment of the present disclosure, if the difference between the width of the calibration block structure in the image and the standard width is less than or equal to the calibration threshold, the camera is not adjusted.

[0135] Step S804: The pole piece winding machine alarms and shuts down.

[0136] If the difference between the width of the calibration block structure in the image and the standard width is greater than the calibration threshold, the pole piece winding machine will alarm and stop, and prompt the engineer to maintain the camera.

[0137] Step S805: prompt the engineer to perform maintenance on the camera.

[0138] The disclosed embodiment uses the ROI frame edge capture algorithm to calculate and determine whether the difference |Δ2| between the real-time value of the calibration block structure width and the actual value 1mm is less than the calibration threshold. Based on the result, the camera is classified as OK or NG, and the information is transmitted to the pole piece winding machine through the PLC to execute shutdown and prompt the engineer to perform equipment maintenance.

[0139] In some embodiments, after the device is repaired, step S801 is continued.

[0140] The disclosed embodiment can also use an area array camera to take continuous photos. In visual imaging, in addition to monitoring the consistency of the width of the inorganic matter at the edge of the positive electrode plate, the lateral offset |Δ3︱ of the plate during movement can also be synchronously monitored. When |Δ3︱≤0.5mm, normal production is carried out. When |Δ3︱>0.5mm, the machine is shut down for maintenance.

[0141] The embodiment of the present disclosure can introduce artificial intelligence (AI) monitoring into the real-time image acquisition system of the camera. When defects such as wrinkles or damage appear on the front and back of the positive electrode, AI can be used to determine and intercept the electrode to ensure that the battery cells are produced from normal and defect-free materials.

[0142] On the one hand, the embodiment of the present disclosure monitors the consistency of the front and back sides of the electrode edge, which is more accurate than the traditional alignment detection system's method of monitoring the electrode edge. The embodiment of the present disclosure greatly eliminates interference from the inorganic insulating layer area and more accurately monitors the alignment of the positive and negative electrode sheets, thereby effectively ensuring that the negative electrode sheet covers the active area of ​​the positive electrode sheet, reducing battery cell problems caused by alignment, and ensuring battery cell safety. On the other hand, the introduction of a calibration block structure to monitor camera accuracy can effectively monitor distortion of electrode alignment detection caused by algorithm anomalies, resolution anomalies, and loose camera hardware, ensuring the normal operation of equipment during the production process and effectively reducing false detections and missed detections of the detection system.

[0143] The embodiment of the present disclosure also uses a CCD camera to monitor whether the edge of the pole piece is offset relative to the initial position. Compared with the detection method in the related art that uses a sensor to determine whether the initial position is offset, the method provided by the present disclosure improves the detection accuracy from 1.5mm to 0.5mm, thereby improving the detection accuracy and reducing false detections and missed detections.

[0144] In addition to meeting the functions of detecting the edge consistency and position stability of the electrode, the embodiment of the present disclosure can also add an appearance defect detection algorithm to the camera to perform appearance inspection on the insulating layer and active area at the edge of the positive electrode, further ensuring the quality and safety of the battery cell.

[0145] It should be noted that the description of the system embodiment of the present disclosure is similar to the description of the above-mentioned method embodiment and has similar beneficial effects as the method embodiment, so it will not be repeated. For technical details not disclosed in the system embodiment, please refer to the description of the method embodiment of the present disclosure for understanding.

[0146] The above description is merely an embodiment of the present disclosure and is not intended to limit the scope of protection of the present disclosure. Any modifications, equivalent replacements, and improvements made within the spirit and scope of the present disclosure are included in the scope of protection of the present disclosure. Industrial Applicability

[0147] The disclosed embodiment obtains images of the first and second sides of the electrode to determine the size parameters of the detection target of the electrode on the first and second sides, and monitors the consistency of the detection targets on the front and back sides of the electrode based on the size parameters of the detection targets on the first and second sides, thereby reducing the problem of misalignment of the detection targets on the front and back sides of the electrode. In this way, on the basis of the alignment of the edges of the positive and negative electrodes, the alignment of the detection targets on the front and back sides of the electrode is guaranteed, so that when the electrode is wound, the negative electrode can cover the active area of ​​the positive electrode, thereby reducing the situation where the battery cell cannot be used due to the misalignment of the positive and negative detection targets, and more accurately monitoring the alignment of the positive and negative electrodes during winding, thereby ensuring the yield and safety of the battery cell.

Claims

1. A pole piece detection method, applied to a camera system, the pole piece detection method comprising: Before the pole piece is wound, a first image of a first surface of the pole piece and a second image of a second surface of the pole piece captured by an image acquisition element are acquired; Determine the size parameters of the detection target in the pole piece on the first surface according to the first image, and determine the size parameters of the detection target in the pole piece on the second surface according to the second image; the detection target at least includes a calibration block corresponding to the pole piece, and the calibration block is used to determine whether the image acquisition element is offset; Based on the size parameters of the first surface and the size parameters of the second surface, a detection result of the pole piece is determined.

2. The pole piece detection method according to claim 1, wherein: The detection target also includes the coating of the pole piece; The step of determining the size parameter of the detection target in the pole piece on the first surface according to the first image, and determining the size parameter of the detection target in the pole piece on the second surface according to the second image, comprises: determining a coating width of the coating on the first surface according to the first image; determining a coating width of the coating on the second surface based on the second image; Correspondingly, determining the detection result of the pole piece based on the size parameter of the first surface and the size parameter of the second surface includes: Determining a coating width difference between the first surface and the second surface of the coating based on the coating width of the first surface and the coating width of the second surface; The coating width difference is compared with a target difference threshold to obtain alignment results of the coating on the first surface and the second surface.

3. The pole piece detection method according to claim 2, wherein: The comparing the coating width difference with a target difference threshold to obtain the alignment result of the coating on the first surface and the second surface includes: In response to the coating width difference being greater than or equal to the target difference threshold, generating a first alignment result indicating that the pole piece does not meet an alignment condition; In response to the coating width difference being less than the target difference threshold, a second alignment result is generated indicating that the pole piece satisfies the alignment condition.

4. The pole piece detection method according to any one of claims 1 to 3, wherein: The image acquisition element comprises a first image acquisition element for acquiring the first image and a second image acquisition element for acquiring the second image; The step of determining the size parameter of the detection target in the pole piece on the first surface according to the first image, and determining the size parameter of the detection target in the pole piece on the second surface according to the second image, comprises: Determining a calibration width of the calibration block on the first surface according to the first image, and determining a calibration width of the calibration block on the second surface according to the second image; Correspondingly, the method further includes: Respectively determining the differences between the calibrated width of the first surface, the calibrated width of the second surface and the standard width of the calibration block to obtain a first calibration difference and a second calibration difference; The first calibration difference value, the second calibration difference value and the calibration difference value threshold value are compared respectively to obtain the offset result of the first image acquisition element and the offset result of the second image acquisition element.

5. The pole piece detection method according to any one of claims 1 to 4, wherein: The step of determining the size parameter of the detection target in the pole piece on the first surface according to the first image, and determining the size parameter of the detection target in the pole piece on the second surface according to the second image, comprises: determining, according to the first image and the second image, a first defect on the first surface, a second defect on the second surface, an area of ​​the first defect, and an area of ​​the second defect; Correspondingly, the pole piece is determined based on the size parameters of the first surface and the size parameters of the second surface. The test results include: In response to the area of ​​the first defect and / or the area of ​​the second defect being greater than a defect area threshold, generating a detection result indicating that the pole piece has a defect; In response to the area of ​​the first defect and the area of ​​the second defect being both smaller than or equal to the defect area threshold, a detection result indicating that the pole piece can be wound is generated.

6. The pole piece detection method according to any one of claims 1 to 5, wherein: The pole piece detection method also includes: Determine a vertical distance between a pole piece boundary and a reference point according to the first image or the second image; In response to the difference between the vertical distance and the standard distance being greater than a distance threshold, a pole piece offset result of the pole piece offset in the pole piece transmission direction is generated.

7. The pole piece detection method according to any one of claims 1 to 6, wherein: The acquiring of a first image of the first surface of the pole piece and a second image of the second surface of the pole piece acquired by the image acquisition element comprises: In response to a trigger signal sent by a controller, acquiring a first image of a first surface of the pole piece and a second image of a second surface of the pole piece acquired by an image acquisition element; The pole piece detection method also includes: The detection result of the pole piece is sent to the controller.

8. A pole piece detection system, the pole piece detection system at least comprising a camera system, the camera system comprising: An image acquisition element, used for acquiring a first image of a first surface of the pole piece and a second image of a second surface of the pole piece before the pole piece is wound; A processor connected to the image acquisition element, the processor is used to determine the size parameters of the detection target in the pole piece on the first surface according to the first image, and to determine the size parameters of the detection target in the pole piece on the second surface according to the second image; the detection target at least includes a calibration block corresponding to the pole piece, and the calibration block is used to determine whether the image acquisition element is offset; Based on the size parameters of the first surface and the size parameters of the second surface, a detection result of the pole piece is determined.

9. The pole piece detection system according to claim 8, wherein: The pole piece detection system also includes: A mounting frame, used for mounting a first image acquisition element and a second image acquisition element; in a transmission direction perpendicular to the pole piece, the first image acquisition element and the second image acquisition element are respectively arranged on both sides of the pole piece; A first light source and a second light source provide illumination for the pole piece; A first bracket is disposed between the first image acquisition element and the first surface; a second bracket is disposed between the second image acquisition element and the second surface; The viewing hole of the first bracket corresponds to the viewing hole on the second bracket, and the first image acquisition element and the second image acquisition element acquire the first image and the second image by acquiring the image of the pole piece through the viewing hole.

10. The pole piece detection system according to claim 9, wherein: The pole piece detection system also includes: Calibration blocks are respectively arranged on the first bracket and the second bracket.

11. The pole piece detection system according to any one of claims 8 to 10, wherein: The pole piece detection system also includes: A controller, the controller being electrically connected to the processor, and configured to send a trigger signal to the camera system in response to the pole piece winding machine starting to work; receive a detection result of the pole piece sent by the camera system, and send the detection result of the pole piece to the pole piece winding machine; The pole piece winding machine is electrically connected to the controller, and is used to perform one of the following processes on the pole piece in response to the detection result: winding, re-inspection and scrapping.

Images