Appearance detection device and method for UV jet printing insulating layer of cylindrical cell

Abstract

The invention discloses a cylindrical cell UV jet printing insulation layer appearance detection device and method, and the device comprises a centering mechanism which is used for aligning the end surfaces of cylindrical cells in the same group; the end face appearance detection mechanism comprises a clamping jaw module, an end face image acquisition device and an acquisition transverse moving module used for driving the end face image acquisition device to move. The cylindrical surface appearance detection mechanism comprises a clamping and rotating module and cylindrical surface image acquisition equipment arranged above the clamping and rotating module, and the clamping and rotating module is used for clamping and rotating a cylindrical battery cell; and the controller is used for processing the end face image acquired by the end face image acquisition equipment and the cylindrical surface image acquired by the cylindrical surface image acquisition equipment, and obtaining an appearance detection result of the UV jet printing insulating layer of the cylindrical battery cell. According to the invention, the identification effect and the detection efficiency of the appearance detection of the UV jet printing insulating layer of the cylindrical cell are obviously improved, the leak detection rate and the false detection rate are reduced, and the requirements of large-scale automatic production can be met.

Description

Technical Field

[0001] This invention belongs to the field of battery manufacturing technology, specifically relating to a device and method for inspecting the appearance of UV-printed insulating layers in cylindrical battery cells. Background Technology

[0002] In the new energy field, the safety and performance of power batteries are of paramount importance, and the insulation coating technology of battery cells, as their core components, is constantly evolving. UV inkjet printing (UV inkjet printing) technology, as an emerging battery cell insulation coating technology, is attracting increasing attention from battery manufacturers. This technology achieves large-dose, highly precise coating coverage by precisely controlling the jetting of UV ink. Compared with the traditional PET blue film process, it has advantages such as lower material cost, higher quality, higher efficiency, and stronger insulation.

[0003] However, during the UV printing process of cylindrical battery cells, surface defects such as foreign objects, dirt, scratches, pinholes, exposed areas, orange peel texture, and ink buildup can occur. This is particularly true for UV printing applications on cylindrical batteries, where the cylindrical electrode surface has rounded corners, the explosion-proof valve surface has grooved sidewalls, and the circumference of the cell is curved. Cylindrical cells present a non-planar inspection environment, posing higher requirements for post-printing visual inspection. Currently, manual visual inspection suffers from low efficiency and high labor costs, and cannot meet the demands of large-scale automated production. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a device and method for inspecting the appearance of UV-printed insulation layers of cylindrical battery cells. This significantly improves the identification effect and detection efficiency of UV-printed insulation layer inspection of cylindrical battery cells, reduces the rate of missed detection and false detection, and can meet the needs of large-scale automated production.

[0005] This invention provides the following technical solution:

[0006] In a first aspect, a device for inspecting the appearance of UV-printed insulating layer of cylindrical battery cells is provided, comprising a controller and a centering mechanism, an end face appearance inspection mechanism and a cylindrical face appearance inspection mechanism arranged sequentially.

[0007] The centering mechanism is used to align the end faces of cylindrical cells within the same group.

[0008] The end face appearance inspection mechanism includes a gripper module, an end face image acquisition device corresponding to the gripper module, and an acquisition traverse module for driving the end face image acquisition device to move.

[0009] The cylindrical surface appearance inspection mechanism includes a clamping and rotating module and a cylindrical surface image acquisition device disposed above the clamping and rotating module. The clamping and rotating module is used to clamp and rotate the cylindrical battery cell.

[0010] The controller is connected to the end face appearance inspection mechanism and the cylindrical surface appearance inspection mechanism respectively, and is used to process the end face image acquired by the end face image acquisition device and the cylindrical surface image acquired by the cylindrical surface image acquisition device, and obtain the appearance inspection results of the UV inkjet printing insulation layer of the cylindrical battery cell.

[0011] In the above technical solution, after the centering mechanism aligns the end faces of the cylindrical cells in the same group, the cylindrical cells enter the end face appearance inspection mechanism. The end face image acquisition device acquires multi-light area end face images of each cylindrical cell, and then enters the cylindrical surface appearance inspection mechanism. The clamping and rotating module clamps and drives the cylindrical cells to rotate. The cylindrical surface image acquisition device acquires the entire cylindrical surface image of each cylindrical cell, thereby realizing the appearance defect detection of the end face, cylindrical surface and other aspects of the cylindrical cells. This solves the problems of low efficiency of manual inspection or single-point light source, unclear single-point detection imaging and incomplete defect detection. It significantly improves the recognition effect and detection efficiency of the appearance inspection of the UV inkjet printing insulation layer of cylindrical cells, and reduces the missed detection and false detection rate.

[0012] Furthermore, a magnetic levitation circulation line is provided between the centering mechanism and the end face appearance inspection mechanism, and a tray for carrying the cylindrical battery cell is provided on the magnetic levitation circulation line.

[0013] The centering mechanism includes support platforms on both sides of the magnetic levitation circulation line and a movable centering plate on the support platforms, with a centering groove formed between the centering plates that matches the size of the cylindrical battery cell.

[0014] In the above technical solution, the tray carrying the cylindrical battery cells moves between the centering mechanism and the end face appearance inspection mechanism via a magnetic levitation circulation line; when a group of cylindrical battery cells moves to the centering mechanism, the end faces of the cylindrical battery cells in the same group are aligned through the centering groove formed by the centering plate; furthermore, since the centering plate is movable, it can be applied to the end face alignment of cylindrical battery cells of different specifications.

[0015] Furthermore, the end face appearance inspection mechanism also includes a gantry frame, a gripper lateral movement module, and a gripper lifting module;

[0016] The gripper lifting module is connected to the gripper module and is used to drive the gripper module to lift and lower. The gripper lateral movement module is connected to the gripper lifting module and is used to drive the gripper lifting module to move laterally. The gripper lateral movement module is installed on the gantry.

[0017] In the above technical solution, the lateral movement module and the lifting module of the gripper can realize the lateral movement and lifting of the gripper module, which makes it easy for the gripper module to clamp a set of cylindrical cells.

[0018] Furthermore, the gripper module includes a support frame, a support plate connected to the support frame, and a plurality of contoured flexible grippers mounted on the support plate, the shape of which is adapted to the cylindrical battery cell.

[0019] In the above technical solution, multiple contoured flexible grippers can hold multiple cylindrical cells in the same group, which facilitates end face inspection and transfer of cylindrical cells between different mechanisms. The shape of the contoured flexible grippers is adapted to the cylindrical cells, and the flexible material design will not damage the printed appearance of the cylindrical surface of the battery.

[0020] Furthermore, the end-face image acquisition device includes an area scan camera and a zoned ring light source arranged opposite each other, and the area scan camera is connected to a fixed-focus lens.

[0021] In the above technical solution, the use of an area scan camera can improve the resolution of the captured images; the use of a zoned ring light source, which is divided into multiple independently controlled LED areas, each of the same size, allows for the sequential lighting of multiple zones, illuminating them from different angles and directions, thereby generating multiple multi-angle illuminated images of the cell end face, which facilitates comprehensive inspection of the appearance of the cylindrical cell end face.

[0022] Furthermore, the cylindrical surface appearance inspection mechanism also includes a camera longitudinal movement module and a camera lateral movement module. The camera lateral movement module is connected to the cylindrical surface image acquisition device and is used to drive the cylindrical surface image acquisition device to move laterally. The camera longitudinal movement module is connected to the camera lateral movement module and is used to drive the camera lateral movement module to move longitudinally.

[0023] In the above technical solution, the longitudinal and lateral movement of the cylindrical image acquisition device can be adjusted by the camera longitudinal movement module and the camera lateral movement module. On the one hand, this can avoid interference when the cylindrical image acquisition device is transporting cylindrical cells by the gripper module. On the other hand, it facilitates the cylindrical image acquisition device to perform individual cylindrical surface imaging and detection of cylindrical cells in a group.

[0024] Furthermore, the cylindrical surface image acquisition device includes a mounting bracket and a line scan camera and a phase linear array light source connected to the mounting bracket, wherein the line scan camera is connected to a line scan lens.

[0025] In the above technical solution, a phase linear array light source is used in conjunction with a line scan camera to image using phase deflection technology, which can highlight the details of different defects on the cylindrical surface and improve the accuracy of defect detection.

[0026] Furthermore, the cylindrical surface appearance inspection mechanism also includes a lifting platform, the upper surface of which is provided with multiple anti-fall brackets, and the lower surface of which is connected to a lifting device;

[0027] The clamping and rotating module includes a first end face fixing plate and a second end face fixing plate disposed opposite to each other on both sides of the lifting platform; a telescopic cylinder is connected to one side of the first end face fixing plate and a flexible clamping head is connected to the other side; a flexible limiting head is provided on one side of the second end face fixing plate and a rotary drive assembly for driving the flexible limiting head to rotate is provided on the other side.

[0028] In the above technical solution, the flexible clamping head is extended to clamp one end of the cylindrical battery cell by the telescopic cylinder, while the other end of the cylindrical battery cell is pressed against the flexible limiting head. The rotation drive component drives the flexible limiting head to rotate the cylindrical battery cell, thereby realizing the acquisition of cylindrical surface graphics by the cylindrical surface image acquisition device.

[0029] Secondly, a method for visual inspection of the UV-printed insulating layer of a cylindrical battery cell is provided, employing the apparatus described in any one of the first aspects, the method comprising the following steps:

[0030] The centering mechanism aligns the end faces of the cylindrical cells in the same group.

[0031] The end-face appearance inspection mechanism uses a gripper module to pick up a group of cylindrical battery cells, and a transverse module drives an end-face image acquisition device to acquire multi-light zone end-face images of each cylindrical battery cell.

[0032] After the end face image acquisition is completed, the gripper module transfers the cylindrical battery cell to the cylindrical surface appearance inspection mechanism. The clamping and rotating module clamps a group of cylindrical battery cells and drives the cylindrical battery cells to rotate. The cylindrical surface image acquisition device acquires cylindrical surface images of each cylindrical battery cell.

[0033] The controller acquires the end face image acquired by the end face image acquisition device and the cylindrical surface image acquired by the cylindrical surface image acquisition device, processes them, and obtains the appearance inspection results of the UV inkjet printing insulation layer of the cylindrical battery cell.

[0034] In the above technical solution, the various institutions work together to achieve the detection of appearance defects in various positions such as the end face and cylindrical surface of the cylindrical cell. This solves the problems of low efficiency of manual inspection or single-point light source, unclear single-point detection imaging, and incomplete defect detection. It significantly improves the recognition effect and detection efficiency of the appearance inspection of the UV-printed insulation layer of the cylindrical cell, and reduces the rate of missed detection and false detection.

[0035] Further processing of the end face image and the cylindrical surface image includes:

[0036] The end-face images of the multi-light-area region are fused to obtain the end-face standard image and the end-face texture image;

[0037] Preprocess the cylindrical surface image to obtain the orthographic reflection image and the shape image of the cylindrical surface;

[0038] Defect recognition algorithms were used to identify defect categories in the standard end face image and end face texture image, the orthographic reflection image of the cylindrical surface and the shape image of the cylindrical surface, respectively, to obtain end face recognition results and cylindrical surface recognition results.

[0039] By performing a logical AND operation between the end face recognition result and the cylindrical face recognition result, the appearance inspection result of the UV inkjet printing insulation layer of the cylindrical battery cell is obtained.

[0040] In the above technical solution, the non-contact appearance defect detection technology based on machine vision fuses multi-light area end-face images to obtain a standard end-face image and an end-face texture image. Preprocessing the cylindrical surface image yields a cylindrical surface orthographic reflection image and a cylindrical surface shape image. A defect recognition algorithm is then used to identify the defect categories in the standard end-face image, the end-face texture image, the cylindrical surface orthographic reflection image, and the cylindrical surface shape image, respectively, resulting in end-face recognition results and cylindrical surface recognition results. The recognition results are then subjected to a logical AND operation to obtain the appearance inspection results of the UV-printed insulation layer of the cylindrical battery cell. This method can meet the requirements for non-planar appearance inspection of cylindrical battery cells, such as R-angle curvature and grooves, and can efficiently identify appearance defects such as foreign objects, dirt, scratches, pinholes, exposed white areas, orange peel texture, and ink accumulation, with high recognition accuracy.

[0041] Compared with the prior art, the beneficial effects of the present invention are:

[0042] (1) The cylindrical battery cell UV inkjet printing insulation layer appearance inspection device provided by the present invention includes a centering mechanism, an end face appearance inspection mechanism and a cylindrical surface appearance inspection mechanism arranged in sequence. After the centering mechanism aligns the end faces of the cylindrical battery cells in the same group, the cylindrical battery cells enter the end face appearance inspection mechanism. The end face image acquisition device performs multi-light area end face image acquisition on each cylindrical battery cell, and then enters the cylindrical surface appearance inspection mechanism. The clamping and rotating module clamps and drives the cylindrical battery cells to rotate. The cylindrical surface image acquisition device performs full cylindrical surface image acquisition on each cylindrical battery cell, thereby realizing the appearance defect detection of the end face, cylindrical surface and other aspects of the cylindrical battery cells. It solves the problems of low efficiency of manual inspection or single point light source, single point detection imaging is not obvious, and defect detection is incomplete. It significantly improves the recognition effect and detection efficiency of the appearance inspection of the cylindrical battery cell UV inkjet printing insulation layer, reduces the missed detection and false detection rate, and can meet the needs of mass automated production.

[0043] (2) The appearance inspection method for UV-printed insulation layer of cylindrical battery cell provided by the present invention is based on non-contact appearance defect detection technology of machine vision. By fusing the multi-light area end face image, the standard end face image and the end face texture image are obtained. By preprocessing the cylindrical surface image, the cylindrical surface orthographic reflection image and the cylindrical surface shape image are obtained. The defect identification algorithm is used to identify the defect categories of the standard end face image and the end face texture image, the cylindrical surface orthographic reflection image and the cylindrical surface shape image, respectively, to obtain the end face identification result and the cylindrical surface identification result. The identification results are then subjected to logical AND operation to obtain the appearance inspection result of UV-printed insulation layer of cylindrical battery cell. This method can meet the non-planar appearance inspection of cylindrical battery cell R-angle curvature, grooves and other defects. It can efficiently identify appearance defects such as foreign objects, dirt, scratches, shrinkage cavities, exposed white, orange peel, ink accumulation and other defects. The identification accuracy is high and the detection efficiency is high. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the main structure of the cylindrical battery cell UV inkjet printing insulation layer appearance inspection device in an embodiment of the present invention;

[0045] Figure 2 This is a three-dimensional structural schematic diagram of the appearance inspection device for UV inkjet printing insulation layer of cylindrical battery cells in an embodiment of the present invention;

[0046] Figure 3 This is a schematic diagram of the centering mechanism in an embodiment of the present invention;

[0047] Figure 4 This is a schematic diagram of the end face appearance inspection mechanism in an embodiment of the present invention;

[0048] Figure 5 This is a schematic diagram of the contour-following flexible gripper in an embodiment of the present invention;

[0049] Figure 6 This is a schematic diagram of the cylindrical surface appearance inspection mechanism in an embodiment of the present invention;

[0050] Figure 7 This is a rear view structural schematic diagram of the cylindrical surface appearance inspection mechanism in an embodiment of the present invention;

[0051] Figure 8 This is a schematic diagram of the lifting device and the anti-fall bracket in an embodiment of the present invention;

[0052] Figure 9 This is a schematic diagram of the clamping and rotating mechanism in an embodiment of the present invention;

[0053] Figure 10 This is a flowchart illustrating the method for inspecting the appearance of the UV-printed insulating layer of a cylindrical battery cell in an embodiment of the present invention.

[0054] The diagram is labeled as follows: 100, Equipment platform; 200, Centering mechanism; 201, Magnetic levitation circulation line; 202, Tray; 203, Centering plate; 204, Support platform; 205, Adjustment hole; 206, Cutting; 300, Cylindrical battery cell; 400, End face appearance inspection mechanism; 401, Gantry frame; 402, Gripper lateral movement module; 403, Gripper lifting module; 404, Gripper module; 405, Acquisition lateral movement module; 406, Area scan camera; 407, Fixed-focus lens; 408, Zoned ring light source; 409, Contour-following flexible gripper. 500. Cylindrical surface appearance inspection mechanism; 501. Camera longitudinal movement module; 502. Camera lateral movement module; 503. Mounting bracket; 504. Lifting device; 505. Anti-fall bracket; 506. Clamping rotation module; 507. Line scan camera; 508. Line scan lens; 509. Phase linear array light source; 510. Lifting platform; 601. Telescopic cylinder; 602. First end face fixing plate; 603. Flexible clamping head; 604. Rotary motor; 605. Synchronous belt; 606. Synchronous pulley; 607. Second end face fixing plate. Detailed Implementation

[0055] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0056] It should be noted that in the description of this invention, the terms "front", "rear", "left", "right", "upper", "lower", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and do not require that this invention must be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0057] In the description of this invention, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0058] Example 1

[0059] like Figure 1 and Figure 2 As shown, this embodiment provides a cylindrical battery cell UV inkjet printing insulation layer appearance inspection device, including a device platform 100, a controller, and a centering mechanism 200, an end face appearance inspection mechanism 400, and a cylindrical face appearance inspection mechanism 500 sequentially arranged on the device platform 100.

[0060] The centering mechanism 200 is used to align the end faces of the cylindrical cells 300 in the same group;

[0061] The end face appearance inspection mechanism 400 includes a gripper module 404, an end face image acquisition device corresponding to the gripper module 404, and an acquisition traverse module 405 for driving the end face image acquisition device to move.

[0062] The cylindrical surface appearance inspection mechanism 500 includes a clamping and rotating module 506 and a cylindrical surface image acquisition device disposed above the clamping and rotating module 506. The clamping and rotating module 506 is used to clamp and rotate the cylindrical battery cell 300.

[0063] The controller is connected to the end face appearance inspection mechanism 400 and the cylindrical surface appearance inspection mechanism 500 respectively, and is used to process the end face image acquired by the end face image acquisition device and the cylindrical surface image acquired by the cylindrical surface image acquisition device, and obtain the appearance inspection result of the UV inkjet printing insulation layer of the cylindrical battery cell.

[0064] In this embodiment, after the centering mechanism 200 aligns the end faces of the cylindrical cells 300 in the same group, the cylindrical cells 300 enter the end face appearance inspection mechanism 400. The end face image acquisition device 400 performs multi-light area end face image acquisition on each cylindrical cell 300, and then enters the cylindrical surface appearance inspection mechanism 500. The clamping and rotating module 506 clamps and drives the cylindrical cells 300 to rotate. The cylindrical surface image acquisition device performs full cylindrical surface image acquisition on each cylindrical cell 300. The controller processes the end face image acquired by the end face image acquisition device and the cylindrical surface image acquired by the cylindrical surface image acquisition device, thereby realizing the appearance defect detection of the end face, cylindrical surface and other aspects of the cylindrical cells 300. This solves the problems of low efficiency of manual inspection or single-point light source, unclear single-point detection imaging and incomplete defect detection. It significantly improves the recognition effect and detection efficiency of the appearance inspection of the UV inkjet insulation layer of cylindrical cells, and reduces the missed detection and false detection rate.

[0065] Example 2

[0066] This embodiment provides a device for inspecting the appearance of the UV-printed insulation layer of a cylindrical battery cell. Based on Embodiment 1, the device further includes a magnetic levitation circulation line 201. The magnetic levitation circulation line 201 extends from the centering mechanism 200 to the end face appearance inspection mechanism 400. The magnetic levitation circulation line 201 is provided with a tray 202 for carrying the cylindrical battery cell 300. The tray 202 carrying the cylindrical battery cell 300 moves between the centering mechanism 200 and the end face appearance inspection mechanism 400 via the magnetic levitation circulation line 201.

[0067] The alignment mechanism 200 includes support platforms 204 located on both sides of the magnetic levitation circulation line 201 and alignment plates 203 movably mounted on the support platforms 204. Alignment slots matching the dimensions of the cylindrical battery cells 300 are formed between the alignment plates 203. When a group of cylindrical battery cells 300 moves to the alignment mechanism 200, the alignment slots formed by the alignment plates 203 align the end faces of the cylindrical battery cells 300 within the same group, ensuring consistency in the acquisition of battery cell end face images and improving the quality of battery cell end face image acquisition. The alignment plates 203 employ a flexible tooling design, preventing secondary damage to the appearance of the printed battery cells.

[0068] The support platform 204 is provided with adjustment holes 205 perpendicular to the extension direction of the magnetic levitation circulation line 201. The centering plate 203 is connected to the support platform 204 by bolts and matching nuts passing through the adjustment holes 205. The position of the centering plate 203 can be adjusted by adjusting the position of the bolts, thus making it suitable for aligning the end faces of cylindrical cells of different specifications. Furthermore, the centering plate 203 has a cutout 206 at the entrance, so that the entrance width of the centering groove gradually decreases, which facilitates the guidance of the cylindrical cell 300.

[0069] The end-face appearance inspection mechanism 400 also includes a gantry frame 401, a gripper lateral movement module 402, and a gripper lifting module 403. The gripper lifting module 403 is connected to the gripper module 404 and is used to drive the gripper module 404 to lift. The gripper lateral movement module 402 is connected to the gripper lifting module 403 and is used to drive the gripper lifting module 403 to move laterally. The gripper lateral movement module 402 is mounted on the gantry frame 401. The gripper module 404 includes a support frame, a support plate connected to the support frame, and multiple contoured flexible grippers 409 mounted on the support plate. The shape of the contoured flexible grippers 409 is adapted to the cylindrical battery cell 300, such as a semi-circular shape.

[0070] After the cylindrical battery cell 300 is aligned, the tray 202 is transferred to the end-face appearance inspection mechanism 400 via the magnetic levitation circulation line 201. The gripper module 404 can be moved laterally and vertically by the gripper lateral movement module 402 and the gripper lifting module 403, facilitating the smooth movement of the gripper module 404 to the cylindrical battery cell 300. Multiple contoured flexible grippers 409 can hold multiple cylindrical battery cells 300 in the same group, facilitating end-face inspection and transfer of cylindrical battery cells between different mechanisms. The shape of the contoured flexible grippers 409 is adapted to the cylindrical battery cell 300, and the flexible material design will not damage the printed appearance of the cylindrical surface. At the same time, there is a certain adjustable distance between each contoured flexible gripper 409 to meet the clamping of a group of cylindrical battery cells on the tray 202.

[0071] The end-face image acquisition device includes a phase array camera 406 and a zoned ring light source 408 arranged opposite to each other. The phase array camera 406 is connected to a fixed-focus lens 407. The end-face image acquisition device moves laterally through the acquisition lateral shift module 405, thereby realizing end-face image acquisition of each cylindrical cell 300 in the same group.

[0072] In this embodiment, in order to improve the quality of image acquisition and ensure the field of view and accuracy requirements of the battery cell end face, a high-resolution camera is selected, specifically a 2D area array camera with more than 20 million pixels. At the same time, since the UV inkjet printing insulation layer is blue and the surface of the cylindrical battery cell 300 is a nickel-plated steel shell, a color area array camera is selected to improve the contrast of defect images.

[0073] In scenarios involving non-planar cell end faces, defects such as the radius (R) of the electrode post and the sidewall of the explosion-proof valve groove are difficult to detect when using a single light source. This results in low signal-to-noise ratio and weak semantic information for defect features in two-dimensional images, hindering detection and classification. Furthermore, traditional lighting methods struggle to highlight the characteristics of micro-defects approaching image resolution limits, leading to insufficient detection effectiveness. This embodiment utilizes a four-zone ring light source. The ring light source is divided into four independently controlled LED regions, each of the same size. By controlling the sequential illumination of the four zones at 0°, 90°, 180°, and 270°, four multi-angle illuminated images of the cell end face are generated, facilitating comprehensive inspection of the cylindrical cell end face appearance.

[0074] The cylindrical surface appearance inspection mechanism 500 also includes a lifting platform 510. The upper surface of the lifting platform 510 is provided with multiple Y-shaped anti-fall brackets 505, and the lower surface of the lifting platform 510 is connected to a lifting device 504. The clamping and rotating module 506 includes a first end face fixing plate 602 and a second end face fixing plate 607 positioned opposite each other on both sides of the lifting platform 510. One side of the first end face fixing plate 602 is connected to a telescopic cylinder 601, and the other side is connected to a flexible clamping head 603. One side of the second end face fixing plate 607 is provided with a flexible limiting head, and the other side is provided with a rotary drive assembly for driving the flexible limiting head to rotate. Further, the rotary drive assembly includes a rotary motor 604, which is connected to multiple synchronous pulleys 606 via a synchronous belt 605. Each flexible limiting head is connected to a synchronous pulley 606 via a rotating shaft passing through the second end face fixing plate 607.

[0075] After the cylindrical battery cell 300 completes the end face appearance inspection, the gripper module 404 clamps a group of cylindrical battery cells and transfers them to the cylindrical surface appearance inspection mechanism 500. The cylindrical battery cells 300 are then placed on the anti-fall bracket 505. The anti-fall bracket 505 is made of flexible material, which has the characteristics of preventing battery cells from falling and preventing UV inkjet coating from scratching. Then, the lifting device 504 lifts the battery cell, and the flexible clamping head 603 is extended to clamp one end of the cylindrical battery cell 300 by the telescopic cylinder 601. At the same time, the other end of the cylindrical battery cell 300 is pressed against the flexible limiting head. The flexible clamping head 603 has a hollow center to avoid large-area contact with the UV inkjet coating. After the cylindrical battery cell 300 is clamped at both ends, the lifting device 504 retracts, and the rotary motor 604 rotates at a preset speed to ensure that the two ends of the battery cell are concentric, so that the cylindrical surface image acquisition device can acquire the cylindrical surface image.

[0076] The cylindrical surface appearance inspection mechanism 500 also includes a camera longitudinal movement module 501 and a camera lateral movement module 502. The camera lateral movement module 502 is connected to the cylindrical surface image acquisition device and is used to drive the cylindrical surface image acquisition device to move laterally. The camera longitudinal movement module 502 is connected to the camera lateral movement module 502 and is used to drive the camera lateral movement module 502 to move longitudinally. The camera longitudinal movement module 501 moves the cylindrical surface image acquisition device to a safe position to avoid interference when the cylindrical surface image acquisition device is transported by the gripper module 404. By driving the cylindrical surface image acquisition device to move laterally through the camera lateral movement module 502, the appearance defect inspection of the cylindrical surface UV inkjet printing of each cylindrical battery cell 300 is realized.

[0077] The cylindrical surface image acquisition device includes a mounting bracket 503 and a line scan camera 507 and a phase linear array light source 509 connected to the mounting bracket 503. The line scan camera 507 is connected to a line scan lens 508. In order to improve the quality of image acquisition and ensure the field of view and accuracy requirements of the cylindrical surface of the battery cell, this embodiment selects a high-resolution camera, specifically a line scan camera with a resolution of 4K or higher. At the same time, in order to highlight the details of different defects, the phase linear array light source 509 is selected to be used in conjunction with the line scan camera 507 to perform phase deflection imaging technology.

[0078] In this embodiment, the gripper lateral movement module 402, gripper lifting module 403, acquisition lateral movement module 405, camera longitudinal movement module 501, and camera lateral movement module 502 can all use existing devices that can achieve their functions, such as the cooperation structure of motors with lead screws, tracks, etc., which will not be described in detail here.

[0079] Example 3

[0080] This embodiment provides a method for visual inspection of the UV-printed insulation layer of cylindrical battery cells, using the apparatus described in Embodiment 2. The specific steps are as follows:

[0081] Step S1: After UV printing and LED curing, the cylindrical battery cell 300 reaches the centering and positioning mechanism 200 via the magnetic levitation circulation line 201, and is guided and aligned at the end by the centering groove between the two centering plates 203.

[0082] In step S2, after the cylindrical battery cell 300 is centered and positioned, the tray 202 is transferred to the end face appearance inspection mechanism 400 via the magnetic levitation circulation line 201. The gripper module 404 is moved to the cylindrical battery cell 300 by the gripper lateral movement module 402 and the gripper lifting module 403. Multiple cylindrical battery cells 300 in the same group are held by multiple contoured flexible grippers 409. The acquisition lateral movement module 405 drives the end face image acquisition device to move, so that the area scan camera 406 can take four multi-angle illuminated end face images of each cylindrical battery cell 300.

[0083] Step S3: After the end face image acquisition is completed, the gripper module 404 transfers the cylindrical battery cell 300 to the cylindrical surface appearance inspection mechanism 500 and places the cylindrical battery cell 300 on the anti-fall bracket 505. The lifting device 504 lifts it up. The flexible gripping head 603 is extended to grip one end of the cylindrical battery cell 300 by the telescopic cylinder 601, while the other end of the cylindrical battery cell 300 is pressed against the flexible limiting head. Then the lifting device 504 retracts, and the rotary motor 604 rotates at a preset speed to ensure that the two ends of the cylindrical battery cell are concentric. The cylindrical surface image acquisition device is driven to move by the camera longitudinal movement module 501 and the camera lateral movement module 502 to acquire images of the cylindrical surface of the cylindrical battery cell 300 one by one.

[0084] Step S4: The controller acquires the end face image acquired by the end face image acquisition device and the cylindrical surface image acquired by the cylindrical surface image acquisition device, and processes them to obtain the appearance inspection results of the UV inkjet printing insulation layer of the cylindrical battery cell.

[0085] Step S41: Perform fusion processing on the multi-light area end face image to obtain the end face standard image and end face texture image.

[0086] Specifically, this embodiment extracts different features by fusing four images of the battery cell's end face. Assuming... , , , Corresponding to , , , The four images of directional lighting are as follows:

[0087] ① By averaging the images from four directions, the effect of uniform illumination (all zones lit simultaneously) can be simulated, generating a standard image of uniform illumination. Since the original acquired image is a color image, it needs to be converted to grayscale first. : ;

[0088] ② Calculate the standard deviation of each pixel across the four images to obtain a standard deviation image. Since the standard deviation image reflects intensity changes, it is affected by both shape and texture. By applying Gaussian blur to the standard deviation image to smooth out the texture effects, a shape image can be obtained. : Where std(*) means to calculate the standard deviation, and axis=0 means to calculate along the first axis (the number of images), that is, for each pixel position, calculate the standard deviation of that position across all images;

[0089] ③ By compensating for illumination variations using a normalized version of the standard image U divided by the shape image S, a texture image can be obtained, where S is normalized to... Avoid dividing by zero in texture images. : Where C is a small constant, avoid dividing by zero;

[0090] Furthermore, by generating and separating different types of images, this invention provides a multi-dimensional analytical perspective for detecting defects in the appearance of battery cell end faces. By comparing the standard image, shape image, and texture image generated through the fusion processing of battery cell end face images, and in combination with the on-site timing requirements, this invention selects the standard image and texture image for subsequent algorithm processing.

[0091] Step S42: Preprocess the cylindrical surface image to obtain the cylindrical surface orthographic reflection image and the cylindrical surface shape image.

[0092] Specifically, the cylindrical image includes eight original phase images and six pre-processed images, including shape... Figure 1 ,shape Figure 2 The methods used include gloss ratio diagram, diffuse reflection diagram, shape diagram, and orthographic reflection diagram. This invention selects the orthographic reflection diagram and shape diagram for subsequent algorithmic processing.

[0093] Step S43: Use a defect recognition algorithm to identify the defect categories of the standard end face image and the end face texture image, the cylindrical surface orthographic reflection image and the cylindrical surface shape image respectively. Combine traditional image processing technology and deep learning algorithm to identify defects such as foreign objects, dirt, scratches, shrinkage holes, exposed white, orange peel, and ink accumulation, and obtain the end face recognition result and the cylindrical surface recognition result.

[0094] Step S44: Perform a logical AND operation between the end face recognition result and the cylindrical face recognition result to obtain the appearance inspection result of the UV inkjet printing insulation layer of the cylindrical battery cell.

[0095] Step S5: Based on the appearance inspection results of the UV inkjet printing insulation layer of the cylindrical battery cell, the unloading robot performs the OK or NG action for the UV inkjet printing coating of the cylindrical battery cell, transfers the battery cells with qualified appearance, and rejects the battery cells with appearance defects.

[0096] The appearance inspection method for UV-printed insulation layer of cylindrical battery cells provided in this embodiment is based on non-contact appearance defect detection technology using machine vision. It obtains a standard end-face image and an end-face texture image by fusing multi-light area end-face images. It also obtains a cylindrical surface orthographic image and a cylindrical surface shape image by preprocessing the cylindrical surface image. A defect recognition algorithm is then used to identify the defect categories of the standard end-face image, the end-face texture image, the cylindrical surface orthographic image, and the cylindrical surface shape image, respectively, yielding end-face recognition results and cylindrical surface recognition results. The recognition results are then subjected to a logical AND operation to obtain the appearance inspection result of the UV-printed insulation layer of the cylindrical battery cell. This method can meet the requirements for non-planar appearance inspection of cylindrical battery cells, such as R-angle curvature and grooves, and can efficiently identify appearance defects such as foreign objects, dirt, scratches, pinholes, exposed white areas, orange peel texture, and ink accumulation, with high recognition accuracy.

[0097] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A device for inspecting the appearance of UV-printed insulating layers in cylindrical battery cells, characterized in that, This includes a controller and a centering mechanism, an end face appearance inspection mechanism, and a cylindrical surface appearance inspection mechanism arranged in sequence. The centering mechanism is used to align the end faces of cylindrical cells within the same group. The end face appearance inspection mechanism includes a gripper module, an end face image acquisition device corresponding to the gripper module, and an acquisition traverse module for driving the end face image acquisition device to move. The cylindrical surface appearance inspection mechanism includes a clamping and rotating module and a cylindrical surface image acquisition device disposed above the clamping and rotating module. The clamping and rotating module is used to clamp and rotate the cylindrical battery cell. The controller is connected to the end face appearance inspection mechanism and the cylindrical surface appearance inspection mechanism respectively, and is used to process the end face image acquired by the end face image acquisition device and the cylindrical surface image acquired by the cylindrical surface image acquisition device, and obtain the appearance inspection results of the UV inkjet printing insulation layer of the cylindrical battery cell.

2. The cylindrical battery cell UV inkjet printing insulation layer appearance inspection device according to claim 1, characterized in that, A magnetic levitation circulation line is provided between the centering mechanism and the end face appearance inspection mechanism, and a tray for carrying cylindrical battery cells is provided on the magnetic levitation circulation line. The centering mechanism includes support platforms on both sides of the magnetic levitation circulation line and a movable centering plate on the support platforms, with a centering groove formed between the centering plates that matches the size of the cylindrical battery cell.

3. The cylindrical battery cell UV inkjet printing insulation layer appearance inspection device according to claim 1, characterized in that, The end face appearance inspection mechanism also includes a gantry frame, a gripper lateral movement module, and a gripper lifting module; The gripper lifting module is connected to the gripper module and is used to drive the gripper module to lift and lower. The gripper lateral movement module is connected to the gripper lifting module and is used to drive the gripper lifting module to move laterally. The gripper lateral movement module is installed on the gantry.

4. The cylindrical battery cell UV inkjet printing insulation layer appearance inspection device according to claim 1, characterized in that, The gripper module includes a support frame, a support plate connected to the support frame, and multiple contoured flexible grippers mounted on the support plate. The shape of the contoured flexible grippers is adapted to the cylindrical battery cell.

5. The cylindrical battery cell UV inkjet printing insulation layer appearance inspection device according to claim 1, characterized in that, The end-face image acquisition device includes a field scan camera and a zoned ring light source arranged opposite each other, and the field scan camera is connected to a fixed-focus lens.

6. The cylindrical battery cell UV inkjet printing insulation layer appearance inspection device according to claim 1, characterized in that, The cylindrical surface appearance inspection mechanism further includes a camera longitudinal movement module and a camera lateral movement module. The camera lateral movement module is connected to the cylindrical surface image acquisition device and is used to drive the cylindrical surface image acquisition device to move laterally. The camera longitudinal movement module is connected to the camera lateral movement module and is used to drive the camera lateral movement module to move longitudinally.

7. The cylindrical battery cell UV inkjet printing insulation layer appearance inspection device according to claim 1, characterized in that, The cylindrical surface image acquisition device includes a mounting bracket and a line scan camera and a phase line array light source connected to the mounting bracket. The line scan camera is connected to a line scan lens.

8. The cylindrical battery cell UV inkjet printing insulation layer appearance inspection device according to claim 1, characterized in that, The cylindrical surface appearance inspection mechanism also includes a lifting platform, the upper surface of which is provided with multiple anti-fall brackets, and the lower surface of which is connected to a lifting device; The clamping and rotating module includes a first end face fixing plate and a second end face fixing plate disposed opposite to each other on both sides of the lifting platform; a telescopic cylinder is connected to one side of the first end face fixing plate and a flexible clamping head is connected to the other side; a flexible limiting head is provided on one side of the second end face fixing plate and a rotary drive assembly for driving the flexible limiting head to rotate is provided on the other side.

9. A method for inspecting the appearance of UV-printed insulating layers in cylindrical battery cells, characterized in that, The method, employing the apparatus according to any one of claims 1 to 8, comprises the following steps: The centering mechanism aligns the end faces of the cylindrical cells in the same group. The end-face appearance inspection mechanism uses a gripper module to pick up a group of cylindrical battery cells, and a transverse module drives an end-face image acquisition device to acquire multi-light zone end-face images of each cylindrical battery cell. After the end face image acquisition is completed, the gripper module transfers the cylindrical battery cell to the cylindrical surface appearance inspection mechanism. The clamping and rotating module clamps a group of cylindrical battery cells and drives the cylindrical battery cells to rotate. The cylindrical surface image acquisition device acquires cylindrical surface images of each cylindrical battery cell. The controller acquires the end face image acquired by the end face image acquisition device and the cylindrical surface image acquired by the cylindrical surface image acquisition device, processes them, and obtains the appearance inspection results of the UV inkjet printing insulation layer of the cylindrical battery cell.

10. The method for inspecting the appearance of the UV-printed insulating layer of a cylindrical battery cell according to claim 9, characterized in that, Processing the end face image and the cylindrical surface image includes: The end-face images of the multi-light-area region are fused to obtain the end-face standard image and the end-face texture image; Preprocess the cylindrical surface image to obtain the orthographic reflection image and the shape image of the cylindrical surface; Defect recognition algorithms were used to identify defect categories in the standard end face image and end face texture image, the orthographic reflection image of the cylindrical surface and the shape image of the cylindrical surface, respectively, to obtain end face recognition results and cylindrical surface recognition results. By performing a logical AND operation between the end face recognition result and the cylindrical face recognition result, the appearance inspection result of the UV inkjet printing insulation layer of the cylindrical battery cell is obtained.

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