Tab detection system and method

Abstract

Disclosed in the present application are a tab detection system and method. The tab detection system comprises: an upper computer, which is electrically connected to a camera provided with a liquid lens, wherein the upper computer is used for outputting multiple voltage signals to the liquid lens and sending an image collection signal to the camera when a battery cell assembly reaches a tab detection station, and the liquid lens is used for adjusting the focal length of the liquid lens on the basis of each voltage signal; and the camera, which is used for collecting, on the basis of the image collection signal and by means of the liquid lens, a first image of a tab of the battery cell assembly after the focal length of the liquid lens is adjusted each time, so as to obtain multiple first images, and sending the multiple first images to the upper computer, wherein the upper computer is further used for fusing the multiple first images into a second image, and performing appearance defect detection on the tab on the basis of the second image to obtain a detection result. Thus, the appearance defect detection of the tab can be realized.

Description

Tab detection system and method

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202410146116.X, filed on February 1, 2024, entitled “Tap Detection System and Method,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the field of visual inspection, and in particular to a tab inspection system and method. Background Art

[0004] During battery production, the cathode, anode, and separator are wound together to form a bare cell. This process can produce bare cells with defects such as folded, misaligned, missing, or cracked tabs, which can have a negative impact on battery safety.

[0005] Therefore, a solution for detecting tab appearance defects is needed. Summary of the Invention

[0006] The present application provides a tab detection system and method, which can detect tab appearance defects.

[0007] In the first aspect, the present application provides a tab detection system, comprising: a host computer, electrically connected to a camera provided with a liquid lens, the host computer being used to output multiple voltage signals to the liquid lens and send an image acquisition signal to the camera when the battery cell assembly arrives at the tab detection station; the liquid lens being used to adjust its own focal length based on each voltage signal; the camera being used to capture a first image of the tab of the battery cell assembly through the liquid lens after each adjustment of the focal length of the liquid lens based on the image acquisition signal, to obtain multiple first images, and to send the multiple first images to the host computer; the host computer is also used to fuse the multiple first images into a second image, perform appearance defect detection on the tab based on the second image, and obtain a detection result.

[0008] Thus, when the battery cell assembly arrives at the tab inspection station, the host computer can output multiple voltage signals to the liquid lens and send an image acquisition signal to the camera. The liquid lens can adjust its focal length based on each voltage signal. The camera can capture a first image of the tab of the battery cell assembly through the liquid lens after each focal length adjustment based on the image acquisition signal, obtaining multiple first images. The multiple first images are sent to the host computer, which can then fuse the multiple first images into a second image and perform appearance defect detection on the tab based on the second image to obtain a detection result. In this way, the appearance defects of the tab can be detected.

[0009] In some embodiments, the focal length of the liquid lens has a linear relationship with the voltage signal. The liquid lens is used to determine the focal length based on each voltage signal and the linear relationship, obtain multiple target focal lengths, and adjust its own focal length based on each target focal length.

[0010] In this way, by using a liquid lens in which the focal length has a linear relationship with the voltage signal, the zoom of the liquid lens can be controlled more conveniently and accurately.

[0011] In some embodiments, the system also includes: a prism electrically connected to a host computer for imaging the tab; the host computer is also used to control the prism to move to the tab area of ​​the battery cell assembly when the battery cell assembly arrives at the inspection station; the camera is used to capture the image of the tab in the prism through the liquid lens after each focal length adjustment of the liquid lens to obtain multiple first images.

[0012] In this way, the image of the tab can be obtained by collecting the image of the tab in the prism without directly photographing the tab, which can save space and solve the problem that the camera cannot enter a narrow space to collect images.

[0013] In some embodiments, the system further includes: a light source module electrically connected to a host computer; the host computer is further configured to control the light source module to light up when the battery cell assembly arrives at the inspection station; and a camera configured to capture the image of the tab in the prism through a liquid lens when the tab is illuminated by the light source module.

[0014] In this way, by illuminating the tab with the light source module, a clearer image of the tab can be captured.

[0015] In some embodiments, the prism includes a reflective area, and the reflective area is used to reflect the first light reflected by the tab to the camera.

[0016] In this way, the prism can form an image of the tab, and the camera can capture the image of the tab in the prism to obtain the tab image.

[0017] In some embodiments, the second light emitted by the light source module is projected onto the tab; the camera is used to capture the position of the tab illuminated by the second light to obtain a first image.

[0018] In this way, the second light emitted by the light source module is projected onto the tab, and the tab can be illuminated by the second light. The camera can capture the position of the tab illuminated by the second light to obtain a clear image of the tab.

[0019] In some embodiments, the host computer includes: a liquid transformer focusing module, electrically connected to the liquid lens, for outputting multiple voltage signals to the liquid lens; an image acquisition control module, electrically connected to the camera, for sending image acquisition signals to the camera; an image fusion module, for fusing multiple first images into a second image; an algorithm processing module, for performing appearance defect detection on the tab based on the second image to obtain a detection result; and a result output module, for outputting the detection result.

[0020] In this way, accurate detection results can be output through the cooperation of the liquid variable pressure focusing module, image acquisition control module, image fusion module, algorithm processing module and result output module.

[0021] In some embodiments, the zoom range of the liquid lens is greater than a preset maximum misalignment of the tabs.

[0022] In this way, it can be applied to image acquisition scenarios with various different tab misalignment amounts, thereby improving the compatibility of the tab detection system.

[0023] In some embodiments, the depth of field of the liquid lens is determined based on a preset maximum misalignment of the tabs and a preset required number of first images.

[0024] In this way, in the case of image acquisition scenarios applicable to different tab misalignments, the depth of field of the liquid lens can be reasonably determined according to the number of images required, so as to select a suitable liquid lens.

[0025] In some embodiments, the depth of field of the liquid lens is greater than a ratio of a preset maximum misalignment of the tabs to a preset required number of the first image.

[0026] In this way, the depth of field of the liquid lens can be accurately determined based on the ratio of the preset maximum misalignment of the tabs to the preset required number of the first image, so as to select a suitable liquid lens.

[0027] In some embodiments, the optical magnification of the liquid lens is determined based on the depth of field and a preset aperture.

[0028] In this way, the optical magnification of the liquid lens can be accurately determined based on the depth of field and the preset aperture, so that a suitable liquid lens can be selected.

[0029] In a second aspect, the present application provides a tab detection method, comprising: when a battery cell assembly arrives at a detection station, outputting multiple voltage signals to a liquid lens through a host computer, so that the liquid lens adjusts its own focal length based on each voltage signal; sending an image acquisition signal to a camera through the host computer, so that the camera collects a first image of the tab of the battery cell assembly through the liquid lens after each adjustment of the focal length of the liquid lens based on the image acquisition signal, thereby obtaining multiple first images; fusing the multiple first images into a second image through the host computer, and performing appearance defect detection on the tab based on the second image to obtain a detection result.

[0030] Thus, when the battery cell assembly arrives at the tab inspection station, the host computer can output multiple voltage signals to the liquid lens and send an image acquisition signal to the camera. The liquid lens can adjust its focal length based on each voltage signal. The camera can capture a first image of the tab of the battery cell assembly through the liquid lens after each focal length adjustment based on the image acquisition signal, obtaining multiple first images. The multiple first images are sent to the host computer, which can then fuse the multiple first images into a second image and perform appearance defect detection on the tab based on the second image to obtain a detection result. In this way, the appearance defects of the tab can be detected.

[0031] In some embodiments, the focal length of the liquid lens has a linear relationship with the voltage signal. The liquid lens is used to determine the focal length based on each voltage signal and the linear relationship, obtain multiple target focal lengths, and adjust its own focal length based on each target focal length.

[0032] In this way, by using a liquid lens in which the focal length has a linear relationship with the voltage signal, the zoom of the liquid lens can be controlled more conveniently and accurately.

[0033] In some embodiments, before sending an image acquisition signal to the camera through the host computer, the method also includes: controlling the prism to move to the tab area of ​​the battery cell assembly through the host computer when the battery cell assembly arrives at the inspection station; using the prism to image the tab; and using the camera to capture the image of the tab in the prism through the liquid lens after each adjustment of the focal length of the liquid lens to obtain a first image.

[0034] In this way, the image of the tab can be obtained by collecting the image of the tab in the prism without directly photographing the tab, which can save space and solve the problem that the camera cannot enter a narrow space to collect images.

[0035] In some embodiments, before sending an image acquisition signal to the camera through the host computer, the method also includes: controlling the light source module to light up through the host computer when the battery cell assembly arrives at the inspection station; using the light source module to illuminate the tab; and using the camera to capture the image of the tab in the prism through the liquid lens when the tab is illuminated by the light source module.

[0036] In this way, by illuminating the tab through the light source module, a clearer image of the tab can be captured.

[0037] In some embodiments, a host computer fuses multiple first images into a second image, including: dividing the multiple first images into regions according to a preset method by the host computer to obtain multiple regions corresponding to each first image; executing, for each of the multiple regions, the following separately by the host computer: determining the clarity of the region in each first image; determining the target region corresponding to the highest clarity from the regions corresponding to the multiple first images; and fusing the target region corresponding to each of the multiple regions into a second image by the host computer.

[0038] In this way, multiple images with unclear areas can be fused into a clear image, and tab detection can be performed more accurately based on the clear image.

[0039] In some embodiments, the zoom range of the liquid lens is greater than a preset maximum misalignment of the tabs.

[0040] In this way, it can be applied to image acquisition scenarios with various different tab misalignment amounts, thereby improving the compatibility of the tab detection system.

[0041] In some embodiments, the depth of field of the liquid lens is determined based on a preset maximum misalignment of the tabs and a preset required number of first images.

[0042] In this way, in the case of image acquisition scenarios applicable to different tab misalignments, the depth of field of the liquid lens can be reasonably determined according to the number of images required, so as to select a suitable liquid lens.

[0043] In some embodiments, the depth of field of the liquid lens is greater than a ratio of a preset maximum misalignment of the tabs to a preset required number of the first image.

[0044] In this way, the depth of field of the liquid lens can be accurately determined based on the ratio of the preset maximum misalignment of the tabs to the preset required number of the first image, so as to select a suitable liquid lens.

[0045] In some embodiments, the optical magnification of the liquid lens is determined based on the depth of field and a preset aperture.

[0046] In this way, the optical magnification of the liquid lens can be accurately determined based on the depth of field and the preset aperture, so that a suitable liquid lens can be selected.

[0047] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, 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 application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0049] FIG1 is a schematic diagram of a battery cell provided in some embodiments of the present application;

[0050] FIG2 is a schematic diagram of a conventional image acquisition device provided in some embodiments of the present application;

[0051] FIG3 is a second schematic diagram of a conventional image acquisition device provided in some embodiments of the present application;

[0052] FIG4 is a schematic diagram of pixel shifting provided by some embodiments of the present application;

[0053] FIG5 is a schematic diagram of an image of a tab provided in some embodiments of the present application;

[0054] FIG6 is a schematic diagram of a tab detection system according to some embodiments of the present application;

[0055] FIG7 is a schematic diagram of a zoom principle of a liquid lens provided in some embodiments of the present application;

[0056] FIG8 is a second schematic diagram of a tab detection system provided by some embodiments of the present application;

[0057] FIG9 is a flowchart of a tab detection method according to some embodiments of the present application;

[0058] FIG10 is a second flowchart of a tab detection method provided in some embodiments of the present application.

[0059] In the accompanying drawings, the drawings are not necessarily drawn to scale. DETAILED DESCRIPTION

[0060] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0061] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0062] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0063] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0064] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0065] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0066] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0067] As mentioned in the background, during the post-production process of prismatic battery cells, the cathode, anode, and separator are first wound together to form a bare cell. Bare cells produced in this process may exhibit defects such as tab folding, tab misalignment, tab missing, and tab cracking, which can have a certain impact on the safety of prismatic batteries. Therefore, tab inspection for visual defects is necessary.

[0068] Tab defect detection first requires ensuring a clear image of the tab edge. After winding, the edges of the different tabs in the bare cell are often not in the same focal plane, making it difficult to determine whether the tab is defective. A widely used method currently uses a motor module to capture images using zoom. The motor drives the camera to capture multiple images at different object distances. These images are then fused to produce a clear image even if the tab is misaligned. Algorithms are then used to analyze and process the image for defects, and the detection results are output to the equipment for classification. This method is applicable to most product inspections.

[0069] Exemplarily, a device for capturing images by moving and zooming a motor module may include: a linear motion module, a high-brightness stroboscopic light source, a prism, a prism moving cylinder, an oil pressure buffer, a 12-megapixel charge coupled device (CCD), a camera pad, a motor, a lens fixing ring, and a module pad.

[0070] To meet the demands of high-speed prismatic battery production, the most widely used solution currently in the market is module mobile zoom. This uses motor movement to dynamically capture the state of the electrode at different object distances, and then uses an algorithm to fuse the images to generate a clear image of the tab. A battery cell can be shown in Figure 1. As shown in Figure 2, each battery cell 210 requires multiple mobile modules 220 to capture different positions of the tab.

[0071] In the actual process of collecting images through the movement and zoom of the motor module, the fused image is often unclear, and the algorithm will judge it as poor, resulting in an increase in the production overkill rate and reduced production efficiency.

[0072] There are two main reasons for this problem: first, motor movement introduces vibration, which causes image shift during image fusion. Second, mechanical installation makes it difficult to ensure that the camera lens's central axis is perfectly aligned with the direction of motion. If there is an angle, positional shift will occur depending on the camera's position. Image fusion requires that the deviation cannot exceed the image resolution at the edge of a tab.

[0073] As shown in Figure 3, during the actual process of capturing the tab image, the angle α between the prism 310 and the battery cell must be greater than 45°, and there will be an angle between the optical axis e of the camera lens and the movement axis f. When the camera moves along the movement axis f, the tab in the camera's field of view will be offset, which may cause ghosting and other effects when the final image is fused.

[0074] As shown in Figure 4, third image 410 is captured before a camera movement, and fourth image 420 is captured after the camera movement. "A" represents the central feature pixel in the image. Because the camera lens's optical axis is at an angle to the axis of movement, the position of A shifts before and after the camera movement.

[0075] Pixel offset will cause the fused image to be unclear. The fused image can be shown in Figure 5, where one tab forms two or more ghost images in the fused image.

[0076] In summary, the following methods exist for detecting tab defects by capturing images through motor module motion zoom: Technical issues:

[0077] 1. During the movement of the motor module, there will be an angle between the optical axis of the camera lens and the motion axis, resulting in frequent pixel offset and unclear fused images. Therefore, high consistency requirements are placed on mechanical installation and debugging.

[0078] 2. Mechanical vibration is unavoidable during motor movement, such as screw lubrication, mechanical wear, servo parameters, assembly level, etc., which can cause image jitter and unclear fused images.

[0079] 3. The space of the tab inspection station is generally small, there are many motors and sensors in the module, it is difficult to separate the strong and weak cables, and maintenance is also inconvenient.

[0080] In response to the above technical problems, the present application provides a tab detection system and method. When a battery cell assembly arrives at the tab detection station, the host computer can output multiple voltage signals to the liquid lens and send an image acquisition signal to the camera. The liquid lens can adjust its focal length based on each voltage signal. The camera can capture a first image of the tab of the battery cell assembly through the liquid lens after each focal length adjustment based on the image acquisition signal, obtaining multiple first images. The multiple first images are sent to the host computer. The host computer can then fuse the multiple first images into a second image and perform appearance defect detection on the tab based on the second image to obtain a detection result. In this way, the appearance defects of the tab can be detected.

[0081] A liquid lens is used in the embodiment of the present application. The liquid lens can adjust its own focal length based on a voltage signal. The camera can capture the image of the tab through the liquid lens each time the focal length of the liquid lens is adjusted without using a motor or moving the camera. Therefore, there will be no pixel offset and no image jitter due to mechanical vibration during the movement of the motor. In addition, there are no large number of motors, sensors and cables, making maintenance easy.

[0082] The tab detection system and method provided in the embodiments of the present application are introduced in detail below.

[0083] FIG6 is a top view of a tab detection system provided in some embodiments of the present application.

[0084] As shown in FIG. 6 , the tab detection system may include: a host computer 610 and a camera 620 .

[0085] The host computer 610 can be electrically connected to a camera 620 provided with a liquid lens 621. The host computer 610 can be used to output multiple voltage signals to the liquid lens 621 and send image acquisition signals to the camera 620 when the battery cell assembly reaches the tab detection station.

[0086] The liquid lens 621 can be used to adjust its focal length based on each voltage signal;

[0087] The camera 620 may be configured to capture a first image of the tab of the battery cell assembly through the liquid lens 621 based on the image acquisition signal after each focal length adjustment of the liquid lens 621, thereby obtaining a plurality of first images, and sending the plurality of first images to the host computer 610;

[0088] The host computer 610 can also be used to fuse multiple first images into a second image, and perform appearance defect detection on the tab based on the second image to obtain a detection result.

[0089] Here, the tabs may include aluminum inner tabs, aluminum outer tabs, copper inner tabs, and copper outer tabs.

[0090] In some embodiments, the host computer 610 may include a liquid voltage-variable focusing module, an image acquisition control module, an image fusion module, an algorithm processing module, and a result output module. The liquid voltage-variable focusing module may be electrically connected to the liquid lens 621 and configured to output multiple voltage signals to the liquid lens 621; the image acquisition control module may be electrically connected to the camera 620 and configured to send image acquisition signals to the camera 620; the image fusion module may be configured to fuse multiple first images into a second image; the algorithm processing module may be configured to perform appearance defect detection on the tab based on the second image to obtain a detection result; and the result output module may be configured to output the detection result.

[0091] In this way, accurate detection results can be output through the cooperation of the liquid variable pressure focusing module, image acquisition control module, image fusion module, algorithm processing module and result output module.

[0092] Specifically, when the battery cell assembly arrives at the tab detection station, the host computer 610 can receive a product arrival signal, and then the host computer 610 can output multiple voltage signals to the liquid lens 621 and send an image acquisition signal to the camera 620. The liquid lens 621 can adjust its own focal length based on each voltage signal. The camera 620 can collect the first image of the tab of the battery cell assembly through the liquid lens 621 based on the image acquisition signal after each adjustment of the focal length of the liquid lens 621, obtain multiple first images, and send the multiple first images to the host computer 610. Then the host computer 610 can fuse the multiple first images into a second image, and perform appearance defect detection on the tab based on the second image to obtain a detection result.

[0093] The zoom principle of a liquid lens is to change the curvature of the liquid within the lens using a voltage signal, thereby achieving zoom. The curvature of the liquid within the liquid lens is inversely correlated with the focal length of the liquid lens. As shown in Figure 7, the greater the curvature of the liquid within the liquid lens, the shorter the focal length of the liquid lens. Curvature 1 < curvature 2 < curvature 3, f1 > f2 > f3.

[0094] Liquid lenses adjust their focus along their optical axis, eliminating pixel offset. Liquid lenses adjust their focal length based on voltage signals, effectively preventing mechanical vibration. Liquid lens solutions eliminate the need for motors and module-related components, making installation relatively simple and facilitating on-site maintenance and adjustment. They also eliminate the need for multiple servo motors and sensors, facilitating cable routing in confined spaces.

[0095] Thus, when the battery cell assembly arrives at the tab inspection station, the host computer can output multiple voltage signals to the liquid lens and send an image acquisition signal to the camera. The liquid lens can adjust its focal length based on each voltage signal. The camera can capture a first image of the tab of the battery cell assembly through the liquid lens after each focal length adjustment based on the image acquisition signal, obtaining multiple first images. The multiple first images are sent to the host computer, which can then fuse the multiple first images into a second image and perform appearance defect detection on the tab based on the second image to obtain a detection result. In this way, the appearance defects of the tab can be detected.

[0096] In some embodiments of the present application, the focal length of the liquid lens may have a linear relationship with the voltage signal. The liquid lens may be used to determine the focal length based on each voltage signal and the linear relationship, obtain multiple target focal lengths, and adjust its own focal length based on each target focal length.

[0097] In this way, by using a liquid lens in which the focal length has a linear relationship with the voltage signal, the zoom of the liquid lens can be controlled more conveniently and accurately.

[0098] Currently, there is no liquid lens suitable for high-speed wire drawing. In order to customize a liquid lens suitable for high-speed wire drawing of square shell batteries, various parameters can be determined according to needs, and the liquid lens can be selected or customized according to the parameters.

[0099] Specifically, the parameters of the liquid lens may include: zoom range, depth of field, and optical magnification.

[0100] Among them, the zoom range can be determined based on the maximum misalignment of the tab. The misalignment of the tab will cause the width of the tab to increase. The greater the misalignment of the tab, the wider the tab will be. If the zoom range is not large enough, it may not be possible to capture a complete image of the tab with a larger width. Therefore, it is necessary to make the zoom range of the liquid lens able to capture a complete image of the tab even when the misalignment of the tab is the maximum. Therefore, the zoom range of the liquid lens can be greater than the preset maximum misalignment of the tab, and the preset maximum misalignment of the tab can be set according to actual conditions. For example, the maximum misalignment of the tab is usually 40mm, and the preset maximum misalignment of the tab can be 40mm, so the zoom range of the liquid lens can be greater than 40mm. In this way, it can be applied to image acquisition scenarios with various different tab misalignments, thereby improving the compatibility of the tab detection system.

[0101] In some embodiments of the present application, the depth of field of the liquid lens may be determined based on a preset maximum misalignment of the tabs and a preset required number of first images.

[0102] Here, the preset required number of first images may be used as the number of times the camera captures images.

[0103] In this way, in the case of image acquisition scenarios applicable to different tab misalignments, the depth of field of the liquid lens can be reasonably determined according to the number of images required, so as to select a suitable liquid lens.

[0104] In some embodiments of the present application, the depth of field of the liquid lens may be greater than a ratio of a preset maximum misalignment of the tabs to a preset required number of the first image.

[0105] Specifically, depth of field is a key parameter in determining the suitability of liquid lenses for high-speed wire drawing production. Within the object space, centered around the working distance at which the lens achieves optimal focus, there exists a range within which the lens can capture a clear image. This range is the depth of field. The depth of field is the quotient of the zoom range and the number of image acquisitions. A larger depth of field reduces the number of image acquisitions required. For example, if the production line requires a 24 PPM production speed, the cycle time is approximately 2.5 seconds. The time required for the cell assembly to move to the inspection station is 1 second, the time required for the prism to move to the tab area is 0.35 seconds, the time required for the camera to acquire the image is 0.8 seconds, and the time required for the prism to retract is 0.35 seconds. If the camera used is a 1200w U-mount monochrome camera with a frame rate of approximately 28 frames, since the image acquisition time is 0.8 seconds, considering acquisition stability, the number of valid acquisitions that can be made is approximately 20, meaning the preset number of first images is 20. If the zoom range is 40mm, the depth of field is 2mm. Since the zoom range needs to be greater than 40mm, the depth of field needs to be greater than 2mm. Considering the stability of the liquid lens voltage zoom, a liquid lens with a depth of field of 3mm can be selected.

[0106] In this way, the depth of field of the liquid lens can be accurately determined based on the ratio of the preset maximum misalignment of the tabs to the preset required number of the first image, so as to select a suitable liquid lens.

[0107] In some embodiments of the present application, the optical magnification of the liquid lens may be determined based on the depth of field and a preset aperture.

[0108] The optical magnification can be calculated using the following formula:

[0109] Depth of field = 2 x Permissible COC x Effective F-number / Optical magnification 2

[0110] Among them, Permissible COC is the permissible circle of confusion diameter, which is usually 0.04mm.

[0111] By calculating with the above formula and taking into account the detection range of the tab and the camera resolution, it can be determined that the optical magnification is between 0.3 and 0.35.

[0112] In summary, you can choose a liquid lens with an optical magnification between 0.3 and 0.35, a depth of field of 3mm, and a zoom range greater than 40mm.

[0113] In this way, the optical magnification of the liquid lens can be accurately determined based on the depth of field and the preset aperture, so that a suitable liquid lens can be selected.

[0114] In some embodiments of the present application, the tab detection system may further include: a prism.

[0115] The prism can be electrically connected to the host computer and can be used to image the tab;

[0116] The host computer can also be used to control the prism to move to the tab area of ​​the battery cell assembly when the battery cell assembly arrives at the inspection station;

[0117] The camera can be used to collect images of the tabs in the prism through the liquid lens after the liquid lens adjusts its focus each time, thereby obtaining a plurality of first images.

[0118] Specifically, the prism may include a driving part and a reflecting area. The driving part is mechanically connected to the reflecting area, and the driving part is electrically connected to the host computer. When the battery cell assembly arrives at the inspection station, the host computer can control the driving part of the prism to move the reflecting area to the pole ear area of ​​the battery cell assembly. The reflecting area can image the pole ear, and then the camera can collect the image of the pole ear in the reflecting area through the liquid lens after each adjustment of the focal length of the liquid lens to obtain multiple first images.

[0119] For example, as shown in FIG8 , when the battery cell assembly arrives at the inspection station, the host computer can control the prism 630 to move to the tab area of ​​the battery cell assembly, and the prism 630 can then image the tab. The liquid lens 621 can zoom in the direction of arrow h, and the camera 620 can collect the image of the tab in the prism 630 through the liquid lens 621 after each adjustment of the focal length of the liquid lens 621 to obtain multiple first images.

[0120] In this way, the image of the tab can be obtained by collecting the image of the tab in the prism without directly photographing the tab, which can save space and solve the problem that the camera cannot enter a narrow space to collect images.

[0121] In some embodiments of the present application, the prism may include a reflective area, and the reflective area may be used to reflect the first light reflected by the tab to the camera.

[0122] In this way, the prism can form an image of the tab, and the camera can capture the image of the tab in the prism to obtain the tab image.

[0123] In some embodiments of the present application, the tab detection system may further include: a light source module.

[0124] Among them, the light source module can be electrically connected to the host computer;

[0125] The host computer can also be used to control the light source module to light up when the battery cell assembly arrives at the inspection station;

[0126] The camera can be used to capture the image of the tab in the prism through the liquid lens when the tab is illuminated by the light source module.

[0127] Here, the host computer may further include a light source control module, which may be used to control the lighting of the light source module.

[0128] Specifically, when the battery cell assembly arrives at the inspection station, the host computer can control the light source module to light up, and after the light source module is lit, it can illuminate the tab. When the tab is illuminated by the light source module, the camera can capture the image of the tab in the prism through the liquid lens.

[0129] In this way, by illuminating the tab with the light source module, a clearer image of the tab can be captured.

[0130] In some embodiments of the present application, the second light emitted by the light source module can be projected onto the tab;

[0131] The camera can be used to capture the position where the tab is illuminated by the second light to obtain a first image.

[0132] In this way, the second light emitted by the light source module is projected onto the tab, and the tab can be illuminated by the second light. The camera can capture the position of the tab illuminated by the second light to obtain a clear image of the tab.

[0133] An embodiment of the present application further provides a tab detection method, which may be executed by a tab detection system. The tab detection method provided in the embodiment of the present application is introduced below.

[0134] FIG9 is a flow chart of a tab detection method provided in some embodiments of the present application.

[0135] As shown in FIG9 , the tab detection method may include the following steps:

[0136] S910, when the battery cell assembly arrives at the inspection station, outputting multiple voltage signals to the liquid lens through the host computer, so that the liquid lens adjusts its focal length based on each voltage signal;

[0137] S920, sending an image acquisition signal to the camera through the host computer, so that the camera acquires a first image of the tab of the battery cell assembly through the liquid lens after each focal length adjustment of the liquid lens based on the image acquisition signal, to obtain multiple first images;

[0138] S930: The host computer fuses the multiple first images into a second image, and performs appearance defect detection on the tab based on the second image to obtain a detection result.

[0139] The specific process of S910-S930 can be found in the above embodiment and will not be repeated here.

[0140] Thus, when the battery cell assembly arrives at the tab inspection station, the host computer can output multiple voltage signals to the liquid lens and send an image acquisition signal to the camera. The liquid lens can adjust its focal length based on each voltage signal. The camera can capture a first image of the tab of the battery cell assembly through the liquid lens after each focal length adjustment based on the image acquisition signal, obtaining multiple first images. The multiple first images are sent to the host computer, which can then fuse the multiple first images into a second image and perform appearance defect detection on the tab based on the second image to obtain a detection result. In this way, the appearance defects of the tab can be detected.

[0141] In some embodiments of the present application, before S920, the method may further include:

[0142] When the battery cell assembly arrives at the inspection station, the host computer controls the prism to move to the tab area of ​​the battery cell assembly;

[0143] Use a prism to image the tab;

[0144] After the liquid lens adjusts its focal length each time, the camera collects the image of the tab in the prism through the liquid lens to obtain multiple first images.

[0145] The specific process can be found in the above embodiment and will not be described again here.

[0146] In this way, the image of the tab can be obtained by collecting the image of the tab in the prism without directly photographing the tab, which can save space and solve the problem that the camera cannot enter a narrow space to collect images.

[0147] In some embodiments of the present application, before S920, the method may further include:

[0148] When the battery cell assembly reaches the inspection station, the host computer controls the light source module to light up;

[0149] Use the light source module to illuminate the tabs;

[0150] When the tab is illuminated by the light source module, the camera captures the image of the tab in the prism through the liquid lens.

[0151] The specific process can be found in the above embodiment and will not be described again here.

[0152] In this way, by illuminating the tab through the light source module, a clearer image of the tab can be captured.

[0153] In some embodiments of the present application, the above-mentioned fusing of the multiple first images into the second image by the host computer may include:

[0154] Dividing the plurality of first images into regions according to a preset method by a host computer to obtain a plurality of regions corresponding to each first image;

[0155] The host computer performs, for each of the multiple regions, the following steps: determining the clarity of the region in each first image; and determining a target region corresponding to the highest clarity from the regions corresponding to the multiple first images.

[0156] The target area corresponding to each area in the plurality of areas is fused into a second image through the host computer.

[0157] Here, the clarity of the same area in multiple first images may be different. For each area, the image with the highest clarity among the multiple images may be selected as the target area. After determining the target area of ​​each area, the multiple target areas may be fused into the second image.

[0158] In this way, multiple images with unclear areas can be fused into a clear image, and tab detection can be performed more accurately based on the clear image.

[0159] In some embodiments of the present application, the focal length of the liquid lens can have a linear relationship with the voltage signal. The liquid lens can be used to determine the focal length based on each voltage signal and the linear relationship, obtain multiple target focal lengths, and adjust its own focal length based on each target focal length.

[0160] In this way, by using a liquid lens in which the focal length has a linear relationship with the voltage signal, the zoom of the liquid lens can be controlled more conveniently and accurately.

[0161] In some embodiments of the present application, the zoom range of the liquid lens may be greater than a preset maximum misalignment of the tabs.

[0162] In this way, it can be applied to image acquisition scenarios with various different tab misalignment amounts, thereby improving the compatibility of the tab detection system.

[0163] In some embodiments of the present application, the depth of field of the liquid lens may be determined based on a preset maximum misalignment of the tabs and a preset required number of first images.

[0164] In this way, in the case of image acquisition scenarios applicable to different tab misalignments, the depth of field of the liquid lens can be reasonably determined according to the number of images required, so as to select a suitable liquid lens.

[0165] In some embodiments of the present application, the depth of field of the liquid lens may be greater than a ratio of a preset maximum misalignment of the tabs to a preset required number of the first image.

[0166] In this way, the depth of field of the liquid lens can be accurately determined based on the ratio of the preset maximum misalignment of the tabs to the preset required number of the first image, so as to select a suitable liquid lens.

[0167] In some embodiments of the present application, the optical magnification of the liquid lens may be determined based on the depth of field and a preset aperture.

[0168] In this way, the optical magnification of the liquid lens can be accurately determined based on the depth of field and the preset aperture, so that a suitable liquid lens can be selected.

[0169] In order to better describe the entire solution, based on the above embodiments, a specific example is given, as shown in FIG10 , the tab detection method may include S1001 - S1010 , which is explained in detail below.

[0170] S1001: When the battery cell assembly arrives at the inspection station, the host computer controls the prism to extend to the tab area.

[0171] S1002, the host computer controls the light source module to light up.

[0172] S1003 , the host computer controls the liquid lens to zoom multiple times, and controls the camera to capture multiple first images.

[0173] S1004: The host computer fuses the multiple first images into a second image.

[0174] S1005: The host computer performs appearance defect detection on the tab based on the second image to obtain a detection result.

[0175] S1006, the host computer outputs the detection result.

[0176] S1007, the host computer controls the liquid lens to reset.

[0177] S1008: The host computer controls the light source module to turn off.

[0178] S1009, the host computer controls the prism to retract.

[0179] S1010, the battery cell assembly leaves the inspection station.

[0180] The specific process of S1001-S1010 can be found in the above embodiment and will not be repeated here.

[0181] Thus, when the battery cell assembly arrives at the tab inspection station, the host computer can output multiple voltage signals to the liquid lens and send an image acquisition signal to the camera. The liquid lens can adjust its focal length based on each voltage signal. The camera can capture a first image of the tab of the battery cell assembly through the liquid lens after each focal length adjustment based on the image acquisition signal, obtaining multiple first images. The multiple first images are sent to the host computer, which can then fuse the multiple first images into a second image and perform appearance defect detection on the tab based on the second image to obtain a detection result. In this way, the appearance defects of the tab can be detected.

[0182] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and components may be replaced with equivalents without departing from the scope of the present application. In particular, the various technical features described in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions within the scope of the claims.

Claims

1. A tab detection system, comprising: A host computer is electrically connected to a camera provided with a liquid lens, and the host computer is used to output multiple voltage signals to the liquid lens and send an image acquisition signal to the camera when the battery cell assembly reaches the tab detection station; The liquid lens is used to adjust its focal length based on each voltage signal; The camera is configured to capture a first image of the tab of the battery cell assembly through the liquid lens based on the image acquisition signal after each focal length adjustment of the liquid lens, to obtain a plurality of first images, and to send the plurality of first images to the host computer; The host computer is further configured to fuse the plurality of first images into a second image, and perform appearance defect detection on the tab based on the second image to obtain a detection result.

2. The system according to claim 1, wherein: The focal length of the liquid lens has a linear relationship with the voltage signal. The liquid lens is used to determine the focal length based on each voltage signal and the linear relationship to obtain multiple target focal lengths, and adjust its own focal length based on each target focal length.

3. The system according to claim 1 or 2, further comprising: A prism, electrically connected to the host computer, for imaging the tab; The host computer is further configured to control the prism to move to the tab area of the battery cell assembly when the battery cell assembly arrives at the inspection station; The camera is used to collect images of the tabs in the prism through the liquid lens after the liquid lens adjusts its focal length each time, so as to obtain the multiple first images.

4. The system according to claim 3, further comprising: A light source module is electrically connected to the host computer; The host computer is further configured to control the light source module to light up when the battery cell assembly reaches the detection station; The camera is used to collect the image of the tab in the prism through the liquid lens when the tab is illuminated by the light source module.

5. The system according to claim 3 or 4, wherein: The prism includes a reflective area, and the reflective area is used to reflect the first light reflected by the tab to the camera.

6. The system according to claim 4, wherein: The second light emitted by the light source module is projected onto the tab; The camera is used to capture the position of the tab illuminated by the second light to obtain the first image.

7. The system according to any one of claims 1 to 6, wherein: The host computer includes: a liquid variable voltage focusing module, electrically connected to the liquid lens, and configured to output the multiple voltage signals to the liquid lens; an image acquisition control module, electrically connected to the camera, and configured to send the image acquisition signal to the camera; an image fusion module, configured to fuse the plurality of first images into the second image; an algorithm processing module, configured to perform appearance defect detection on the tab based on the second image to obtain the detection result; The result output module is used to output the detection result.

8. The system according to any one of claims 1 to 7, wherein: The zoom range of the liquid lens is greater than the preset maximum misalignment of the tab.

9. The system according to claim 8, wherein: The depth of field of the liquid lens is determined based on the preset maximum misalignment of the tabs and a preset required number of the first images.

10. The system according to claim 9, wherein: The depth of field of the liquid lens is greater than the ratio of the preset maximum misalignment of the tab to the preset required number of the first image.

11. The system according to claim 9 or 10, wherein: The optical magnification of the liquid lens is determined based on the depth of field and a preset aperture.

12. A tab detection method comprising: When the battery cell assembly arrives at the inspection station, a plurality of voltage signals are output to the liquid lens through the host computer, so that the liquid lens adjusts its focal length based on each of the voltage signals; Sending an image acquisition signal to a camera through the host computer, so that the camera acquires a first image of the tab of the battery cell assembly through the liquid lens after the liquid lens adjusts its focal length each time based on the image acquisition signal, thereby obtaining a plurality of first images; The host computer fuses the multiple first images into a second image, and performs appearance defect detection on the tab based on the second image to obtain a detection result.

13. The method according to claim 12, wherein: The focal length of the liquid lens has a linear relationship with the voltage signal. The liquid lens is used to determine the focal length based on each voltage signal and the linear relationship to obtain multiple target focal lengths, and adjust its own focal length based on each target focal length.

14. The method according to claim 12 or 13, before the host computer sends the image acquisition signal to the camera, the method further comprises: When the battery cell assembly arrives at the inspection station, the host computer controls the prism to move to the tab area of the battery cell assembly; Imaging the tab using the prism; The camera is used to collect images of the tabs in the prism through the liquid lens after the focal length of the liquid lens is adjusted each time, so as to obtain the multiple first images.

15. The method according to claim 14, before sending the image acquisition signal to the camera through the host computer, the method further comprises: When the battery cell assembly reaches the detection station, the host computer controls the light source module to light up; Using the light source module to illuminate the tab; When the tab is illuminated by the light source module, the camera collects the image of the tab in the prism through the liquid lens.

16. The method according to any one of claims 12 to 15, wherein: The fusing of the plurality of first images into a second image by the host computer includes: Dividing the plurality of first images into regions by the host computer according to a preset method to obtain a plurality of regions corresponding to each first image; The host computer performs, for each of the plurality of regions, respectively: determining the clarity of the region in each of the first images; and determining a target region corresponding to the highest clarity from the regions respectively corresponding to the plurality of first images; The host computer fuses the target area corresponding to each area in the multiple areas into the second image.

17. The method according to any one of claims 12 to 16, wherein: The zoom range of the liquid lens is greater than the preset maximum misalignment of the tab.

18. The method according to claim 17, wherein: The depth of field of the liquid lens is determined based on the preset maximum misalignment of the tabs and a preset required number of the first images.

19. The method according to claim 18, wherein The depth of field of the liquid lens is greater than the ratio of the preset maximum misalignment of the tab to the preset required number of the first image.

20. The method according to claim 18 or 19, wherein The optical magnification of the liquid lens is determined based on the depth of field and a preset aperture.

Images