Tab cracking detection method and device, tab welding equipment and battery production system

Abstract

The embodiment of the invention provides a tab cracking detection method and device, tab welding equipment and a battery production system. The tab cracking detection method comprises the following steps: acquiring three-dimensional coordinate data of a plurality of reference areas to construct a reference surface; acquiring three-dimensional coordinate data of the surface of the tab, and determining a to-be-detected analysis area of the tab by comparing the height characteristic difference between the surface of the tab and the reference surface; and determining a detection result of whether the tab is cracked or not based on at least one of a height difference criterion and a morphology mutation criterion of the to-be-detected analysis area relative to the reference surface. Compared with a traditional manual visual inspection mode, the detection accuracy of quality defects such as tab cracking can be remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, and more particularly, to a tab cracking detection method and device, a tab welding device, and a battery production system. BACKGROUND

[0002] Battery devices are widely used in electronic devices, such as mobile phones, notebook computers, electric vehicles, electric cars, electric planes, electric ships, electric toy cars, electric toy ships, electric toy planes, and electric tools, etc.

[0003] In the production process of battery devices, it is necessary to detect defects of tabs, such as cracking detection of tabs in the welding process. How to improve the accuracy of tab cracking detection is a research direction in the technical field of batteries. SUMMARY

[0004] The present application provides a tab cracking detection method and device, a tab welding device, and a battery production system, which can improve the accuracy of tab cracking detection. In a first aspect, the embodiments of the present application provide a tab cracking detection method, comprising the following steps: obtaining three-dimensional coordinate data of a plurality of reference areas to construct a reference surface; obtaining three-dimensional coordinate data of a tab surface, and determining a to-be-detected analysis area of the tab based on a height characteristic difference between the tab surface and the reference surface according to the three-dimensional coordinate data; comparing height difference and topography of the to-be-detected analysis area and the reference surface, and determining a detection result of whether the tab cracks based on at least one of a height difference criterion and a topography mutation criterion.

[0005] By using the above technical solution, the construction of the reference surface and the analysis of the height difference can effectively reduce the interference caused by assembly errors and uneven substrates, so that the detection result more truly reflects the welding quality. Moreover, the height difference criterion can accurately identify the local height mutation caused by the edge cracking of the welding mark area, and the detection sensitivity is higher. In addition, the topography mutation criterion can capture the crack characteristics of any direction through three-dimensional curvature analysis, which significantly improves the accuracy of quality defect detection such as tab cracking compared with the traditional manual visual inspection method.

[0006] In some embodiments of the present application, the step of determining the to-be-detected analysis area of the tab based on the height characteristic difference between the tab surface and the reference surface according to the three-dimensional coordinate data comprises: determining the spatial position range of the welding mark area of the tab by comparing the height characteristic difference between the tab surface and the reference surface; The preset boundary is extended to a first direction and a second direction according to a spatial position range of the welding mark area, the first direction and the second direction intersect and are respectively parallel to the tab surface.

[0007] By using the above technical solution, the three-dimensional coordinate data of the tab welding surface is acquired as the basis of the to-be-detected analysis area, and then the welding mark area is expanded to form the to-be-detected analysis area, so that the welding mark strength deficiency and edge cracking defects can be found synchronously, and the crack detection rate is improved.

[0008] In some embodiments of the present application, the width of the preset boundary extended to the first direction is 3 mm to 10 mm, and / or the width of the preset boundary extended to the second direction is 3 mm to 10 mm.

[0009] By using the above technical solution, the expansion width of the outwardly expanded preset boundary is 3 mm to 10 mm, which can not only ensure the coverage of the heat-affected zone to capture the tiny cracks, but also detect the far-end defects of stress diffusion.

[0010] In some embodiments of the present application, the step of acquiring the three-dimensional coordinate data of the tab surface comprises: laser scanning the reference area to acquire the three-dimensional coordinate data of a plurality of sampling points; adopting a statistical analysis method to eliminate noise points in the three-dimensional coordinate data; generating the reference surface based on the data after eliminating the noise points.

[0011] By using the above technical solution, the statistical analysis effectively eliminates the noise points to improve the data accuracy, and the reference surface generated based on the fitting improves the data reliability and consistency, so that the overall process is efficient and highly automated.

[0012] In some embodiments of the present application, the statistical analysis method is a mean ± 3 standard deviation criterion.

[0013] By using the above technical solution, the mean ± 3 standard deviation criterion is simple and easy to implement, can effectively identify and eliminate abnormal points that significantly deviate from the normal distribution, while maintaining the overall distribution characteristics of the data, and improve the accuracy of the fitted reference surface.

[0014] In some embodiments of the present application, the step of determining the detection result of whether the tab is cracked comprises: when any one of the height difference criterion and the topographic mutation criterion is met, it is determined that the tab is cracked.

[0015] By using the above technical solution, as long as any one criterion is triggered, the defect is reported, the dual sensitivity of height abnormality and topographic mutation is realized, the possibility of missed detection can be reduced, the crack detection rate is greatly improved, and the algorithm is efficient and simple.

[0016] In some embodiments of the present application, the height difference criterion comprises: the height difference between any point in the to-be-detected analysis region and the reference surface exceeds a preset first threshold.

[0017] By setting the first threshold of the height difference, the welding defects can be directly quantified, and when the deviation between the detection point and the reference surface exceeds the first threshold, typical defects such as virtual welding or welding through can be quickly determined, which ensures the detection sensitivity and avoids misjudgment, thereby improving the detection efficiency and reliability.

[0018] In some embodiments of the present application, the topography mutation criterion comprises: a topography mutation criterion along a first coordinate axis direction and / or a topography mutation criterion along a second coordinate axis direction.

[0019] By detecting the topography mutation in multiple coordinate axes, the crack defects in multiple directions can be more accurately captured, and the crack detection rate and detection reliability are significantly improved.

[0020] In some embodiments of the present application, the topography mutation criterion is determined by: performing linear fitting on the topography change curve along the specified coordinate axis direction in the to-be-detected analysis region, and the fitting slope exceeds a second threshold.

[0021] By quantifying the topography mutation degree through the linear fitting slope, the micro crack characteristics can be accurately identified, the subjective misjudgment possibility is reduced, the detection result is objective and reliable, and the sensitivity is adjustable.

[0022] In some embodiments of the present application, a first surface of the adapter tab used for welding with the tab is selected as the reference region, and a second surface of the tab away from the first surface is selected as the to-be-detected analysis region.

[0023] By constructing the reference surface through the first surface of the adapter tab and detecting the deformation of the second surface of the tab, the real deformation caused by the welding stress is directly reflected, the assembly error interference is reduced, and the defect detection precision is significantly improved.

[0024] In some embodiments of the present application, after the detection result of whether the tab is cracked is determined, the tab cracking detection method further comprises: presenting the judgment result of the welding quality of the tab on a display.

[0025] By presenting the judgment result in a visual manner, the judgment result can be directly obtained by the working staff using the display device.

[0026] In a second aspect, the embodiments of the present application provide a tab cracking detection device, comprising a three-dimensional scanning unit, a data processing unit, and a judging unit; the three-dimensional scanning unit is configured to obtain three-dimensional coordinate data of a plurality of reference regions and obtain three-dimensional coordinate data of a tab surface; the data processing unit is configured to construct a reference surface based on the three-dimensional coordinate data of the plurality of reference regions, and configured to determine a to-be-detected analysis region of the tab by comparing height characteristic differences between the tab surface and the reference surface, and further configured to obtain a height difference criterion and a topography mutation criterion of the to-be-detected analysis region compared with the reference surface; and the judging unit is configured to determine a detection result of whether the tab cracks by at least one of the height difference criterion and the topography mutation criterion.

[0027] The tab cracking detection device is designed to comprise the three-dimensional scanning unit, the data processing unit, and the judging unit, the three-dimensional scanning unit can quickly obtain high-precision surface topography data, the data processing unit can effectively eliminate assembly errors by constructing the reference surface, the height difference and the topography mutation double criteria are combined to ensure the comprehensiveness of the crack detection, the judging unit uses an algorithm to realize more accurate defect determination, and the detection efficiency and accuracy are better than those of artificial detection.

[0028] In a third aspect, the embodiments of the present application provide a tab welding device, comprising a base, a welding device, and a tab cracking detection device according to any one of the above technical solutions; the base is configured to place an electrode assembly and an adapter sheet; the welding device is configured to weld a tab of the electrode assembly and the adapter sheet located on the base; the tab cracking detection device comprises a laser scanner and a processor; the laser scanner is configured to obtain three-dimensional coordinate data of a plurality of reference regions to construct a reference surface; the processor is configured to obtain three-dimensional coordinate data of a tab surface, and determine a to-be-detected analysis region of the tab based on a comparison of height characteristic differences between the tab surface and the reference surface; and the processor is further configured to compare a height difference and a topography of the to-be-detected analysis region with the reference surface, and determine a detection result of whether the tab cracks based on at least one of a height difference criterion and a topography mutation criterion.

[0029] The above technical solution can be used to detect the welding quality of the tab during the welding process by the tab cracking detection device, so as to monitor the welding quality of the tab in real time and reduce the possibility of defective products flowing into the next process; and the detection data can be directly fed back to adjust the welding parameters, thereby realizing process closed-loop control.

[0030] In some embodiments of the present application, the tab welding device further comprises a shock absorber, and the base is mounted on the shock absorber.

[0031] The above technical solution can be used to mount the base on the shock absorber, thereby reducing the shaking of the base during the welding process and improving the testing accuracy of the tab cracking detection device.

[0032] In a fourth aspect, an embodiment of the present application provides a battery production system, comprising a transfer device and a tab welding device as described in the above technical solution, wherein the transfer device is used to transfer cracked tabs detected by the tab cracking detection device of the tab welding device to a defective product area. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0034] Figure 1 A flowchart of a tab crack detection method provided in some embodiments of the present application; Figure 2 A schematic structural diagram of a tab crack detection device provided in some embodiments of the present application; Figure 3 A schematic diagram of the structure of the electrode assembly and the adapter plate after welding provided in some embodiments of the present application; Figure 4 Schematic diagram of the structure of the electrode assembly provided in some embodiments of the present application Figure 5 for Figure 4 A magnified view of part a; Figure 6 A schematic diagram of the structure of the tab welding equipment provided in some embodiments of the present application during welding; Figure 7 A schematic diagram of the structure of the tab welding equipment provided in some embodiments of the present application when performing welding quality inspection.

[0035] The reference numerals for the specific embodiments are as follows: 100. Tab welding equipment; 10. Base; 20. Welding equipment; 30. Tab crack detection device; 31. 3D scanning unit; 32. Data processing unit; 33. Judgment unit; 40. Shock absorber; 200, electrode assembly; 210, tab; 211, second surface; 2111, weld imprint area; 2112, area to be tested and analyzed; 300, adapter; 310, first surface; X, first direction; Y, second direction; Z, third direction. DETAILED DESCRIPTION

[0036] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0037] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used in the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the description of the present application and the claims and the above description of drawings are intended to cover the non-exclusive inclusion. The terms "first", "second" and the like in the description of the present application and the claims are used to distinguish different objects, not to describe a particular order or primary and secondary relationship.

[0038] In the present application, the term "embodiment" means that the specific features, structures or characteristics described in conjunction with the embodiment can 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 is it an independent or alternative embodiment to other embodiments.

[0039] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mount", "connect", "connection", "attach" should be understood broadly, for example, it can be fixedly connected, or detachably connected, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0040] In the present application, the term "and / or" is only a description of the association relationship between the associated objects, which means that there can be three relationships, for example, A and / or B can mean that A exists alone, A and B exist together, and B exists alone. In addition, the character " / " in the present application generally represents an "or" relationship between the front and rear associated objects.

[0041] In the embodiments of the present application, the same reference signs represent the same components, and for the sake of brevity, the detailed description of the same components is omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device, are only exemplary and should not constitute any limitation on the present application.

[0042] The term "plurality" used in this application refers to two or more (including two).

[0043] The battery cells in the embodiments of this application include an electrode assembly (including positive and negative electrode plates and separators), a transition piece, and an electrolyte. The positive electrode plate includes an aluminum current collector and a positive electrode active material layer (such as lithium cobalt oxide, lithium iron phosphate, etc.) on its coated area, and an uncoated positive electrode tab. The negative electrode plate includes a copper current collector and a negative electrode active material layer (such as carbon, silicon, etc.) on its coated area, and an uncoated negative electrode tab. The separator is made of materials such as PP or PE. This type of battery cell can be widely used in various electrical devices, including vehicles (fuel vehicles / new energy vehicles), electronic devices (mobile phones, laptops), spacecraft (aircraft, rockets), electric toys (electric car toys), and electric tools (electric drills, electric wrenches). This application does not limit specific application scenarios.

[0044] Below, the embodiments of the present application are described in detail.

[0045] As the core component of a battery device, the tabs of a battery cell play a crucial role in transmitting current during the charging and discharging process. The integrity of the tabs directly affects the conductivity and safety of the battery cell. In actual production, the tabs are prone to cracking during welding with the adapter.

[0046] Currently, the industry mainly relies on manual visual inspection, which is inefficient and has low recognition accuracy. Although related technologies exist to indirectly determine the status of the tabs by testing the ohmic internal resistance of battery cells, the internal resistance value is affected by multiple factors such as electrode materials, electrolytes, and temperature. The reliability of the test results is insufficient, which can easily lead to the omission of defective battery cells, posing a serious safety hazard.

[0047] Therefore, how to improve the efficiency and accuracy of tab defect detection is an important issue in battery production and processing.

[0048] In view of this, the present application provides a technical solution, which uses the surface of the adapter as a reference area to construct a reference plane, and uses the reference plane to determine the area of ​​the tab to be detected and analyzed, and detects the height difference and morphological mutation of the area to be detected and analyzed to determine whether the tab is cracked, which can effectively improve the accuracy and efficiency of the tab crack detection.

[0049] The following is combined with Figures 1-7 The tab crack detection method and device, tab welding equipment, and battery production system provided in the embodiments of the present application are introduced.

[0050] Combined with attachment Figure 1 As shown, the embodiment of the present application provides a tab crack detection method, comprising the following steps: acquire three-dimensional coordinate data of a plurality of reference regions to construct a reference surface; acquire three-dimensional coordinate data of the tab 210 surface, determine the to-be-detected analysis area 2112 of the tab 210 based on the height characteristic difference between the tab 210 surface and the reference surface according to the three-dimensional coordinate data; compare the height difference and the topography of the to-be-detected analysis area and the reference surface, and determine the detection result of whether the tab 210 is cracked based on at least one of the height difference criterion and the topography mutation criterion of the to-be-detected analysis area 2112 compared with the reference surface.

[0051] In the above method steps, the three-dimensional coordinate data of a plurality of reference regions can be acquired by a 3D profiler, a laser scanner or a laser tracker, etc. The three-dimensional coordinate data of a plurality of points need to be acquired in each reference region, for example, the three-dimensional coordinate data of 500-2000 points. The area of the sampling spot of each point can be a micron-level spot (1 μm x 1 μm to 50 μm x 50 μm), a sub-millimeter-level spot (0.1 mm x 0.1 mm to 0.5 mm x 0.5 mm) or a millimeter-level spot (1 mm x 1 mm to 5 mm x 5 mm). This embodiment does not enumerate one by one.

[0052] For example, the three-dimensional coordinate data of four reference regions in Figure 3 is collected. After the three-dimensional coordinate data of the four reference regions is collected, the noise points are removed according to mean ± 3sigma (mean ± 3 times standard deviation screening method), and then the reference surfaces 1' & 2' & 3' & 4' for calculating the height difference are constructed.

[0053] Specifically, first, the Z coordinate data collected in each reference region is statistically analyzed, the arithmetic mean μ and the standard deviation σ of the third direction Z coordinate (vertical direction coordinate) of all sampling points in the region are calculated, the effective data range is set as [μ-3σ, μ+3σ], the collected data is filtered and denoised to eliminate errors and interference in the scanning process, and the abnormal data points outside the range are removed to retain the effective data point set; then the least square method is used to fit the plane of the effective data point set of each region, and the plane equation Z=aX+bY+c is established, the optimal plane parameters a, b, c are solved by minimizing the square sum of the vertical distance of each point to the plane, and finally the fitted plane is defined as the reference surface (reference surface 1' to reference surface 4') of each region. Wherein, μ represents the average value of Z coordinate, σ represents the standard deviation of Z coordinate, a, b, c are the coefficients of the plane equation.

[0054] After the component reference surface is constructed, the three-dimensional coordinate data of the tab 210 surface is acquired again, and the to-be-detected analysis area 2112 of the tab 210 is determined based on the height characteristic difference between the tab 210 surface and the reference surface according to the three-dimensional coordinate data. Figure 3The number of the tab 210 in the above-mentioned example is four, and the four tabs 210 correspond to the four reference areas one by one. Since the to-be-detected analysis area 2112 of the tab 210 has a certain height characteristic difference with the reference surface, the height characteristic difference is used to divide the to-be-detected analysis area 2112. The to-be-detected analysis area 2112 can be the upper surface (the second surface 211) of the entire tab 210, or can be a region obtained by outward expansion of the welding mark area 2111 of the tab 210. Details are given below. Figure 4

[0055] After the to-be-detected analysis area is determined, the three-dimensional coordinate data of the points in the to-be-detected analysis area are compared with the reference surface to obtain at least one of a height difference criterion and a topography mutation criterion of the to-be-detected analysis area compared with the reference surface, so as to determine whether the tab 210 has defects.

[0056] The height difference criterion refers to the distance difference in the vertical direction (the third direction Z in the figure) between the detection point and the reference surface, which is used to quantify the protrusion or depression degree of the point relative to the reference surface, and the value is equal to the algebraic difference between the Z coordinate of the point and the Z value of the reference surface corresponding to the (X, Y) position of the point.

[0057] The topography mutation criterion is to identify the steep region of the surface by analyzing the height variation gradient or curvature feature between adjacent detection points. When the height difference or curvature of adjacent points exceeds a preset second threshold, it is determined that the topography is mutated.

[0058] The normal welding mark area 2111 of the tab 210 and the surrounding area of the welding mark area 2111 are in the same plane and have no obvious height difference. When the tab 210 of the welding mark area 2111 cracks, the foil of the cracking area will be raised and form a height jump with the welding mark area 2111. By detecting whether there is a height difference or topography mutation (height jump) between the welding mark area 2111 and the surrounding area, it can be determined whether the tab 210 cracks. This method can more accurately detect whether the tab 210 cracks, eliminate the risk of missing detection caused by manual visual inspection, and improve the safety and reliability of the battery cell.

[0059] The above-mentioned method based on the reference surface construction and height difference analysis can effectively reduce the interference caused by assembly errors and uneven base materials, so that the detection result more truly reflects the welding quality. Moreover, the height difference criterion can accurately identify the local height mutation caused by the edge cracking of the welding mark area, and the detection sensitivity is higher. In addition, the topography mutation criterion can capture the crack characteristics of any direction through three-dimensional curvature analysis, which significantly improves the accuracy of the tab 210 cracking and other quality defect detection compared with the traditional manual visual inspection method.

[0060] ​In some examples, the step of determining the to-be-detected analysis area 2112 of the tab 210 based on the comparison of the height characteristics difference between the surface of the tab 210 and the reference surface includes: obtaining three-dimensional coordinate data of the welding surface of the tab 210, and determining the spatial position range of the welding mark area 2111 of the tab 210 by comparing the height characteristics difference between the surface of the tab 210 and the reference surface; extending the preset boundary in the first direction X and the second direction Y to form the to-be-detected analysis area 2112 according to the spatial position range of the welding mark area 2111, the first direction X and the second direction Y intersecting and being parallel to the surface of the tab 210.

[0061] wherein the welding mark area 2111 of the tab 210 is as shown in Figure 4 and 5 The welding mark area 2111 of the tab 210 refers to a specific area formed by the welding position of the tab 210 and the battery current collector or other connecting components in the battery device manufacturing process through the welding process. In the present embodiment, the welding mark area 2111 refers to the area formed by the welding of the tab 210 and the adapter sheet 300.

[0062] Since the welding mark area 2111 of the tab 210 is usually a recessed structure, after obtaining the three-dimensional coordinate data of the welding surface (the second surface 211 in the figure) of the tab 210, the welding mark area 2111 can be directly determined by using the height characteristics difference between the second surface 211 and the reference surface, wherein the height characteristics difference can be understood as the height difference of the three-dimensional coordinates.

[0063] After determining the welding mark area 2111, the welding mark area 2111 is expanded to form the to-be-detected analysis area 2112 (for the convenience of display, the to-be-detected analysis area 2112 is displayed in a dashed box in the figure in the present embodiment), and the reason for this design is that the cracking of the tab 210 is often not limited to the inside of the welding mark area 2111, but can also extend to the substrate area near the welding edge. Simply detecting the welding mark area 2111 can miss the tiny cracks or potential defects at the edge, and the expanded to-be-detected analysis area 2112 can cover the welding mark and the area near the welding mark that may be affected by heat or mechanical stress concentration, thereby more comprehensively capturing the cracking risk points and ensuring the comprehensiveness and accuracy of the detection.

[0064] The method has the advantages that the detection rate can be effectively reduced by expanding the detection range, especially for small cracks or hidden defects at the edge of the welding mark, and meanwhile, the expanded area can provide more background information and contrast basis for image processing or sensor detection, thereby improving the robustness and detection sensitivity of the algorithm. In addition, the unified detection area can help standardize the detection process and reduce detection errors caused by the position deviation or size difference of the tab 210, thereby improving the efficiency and consistency of batch detection on the production line.

[0065] In some examples, the width of the preset boundary expanded in the first direction X is 3mm to 10mm, and / or the width of the preset boundary expanded in the second direction Y is 3mm to 10mm.

[0066] In some embodiments, the size of the preset boundary expanded in the first direction X and the second direction Y can both be L, and L can be 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, etc., which will not be listed one by one in this embodiment.

[0067] The expansion width of the outwardly expanded preset boundary is 3mm to 10mm, which can effectively cover the area around the welding mark of the tab 210 that may be affected by heat or stress concentration, so that small cracks or potential defects are detected, and the possibility of excessive expansion leading to a too large detection area and introducing irrelevant background interference is reduced, thereby balancing the detection accuracy and efficiency.

[0068] The lower limit of 3mm can ensure the capture of typical cracks at the edge of the welding mark (such as heat-affected zone micro-cracks), and the upper limit of 10mm can adapt to different tab 210 sizes and process fluctuations, reduce the possibility of detection omission caused by tab 210 position deviation or welding offset, and at the same time, this width range is also convenient for standardizing the detection process, adapting to the resolution and field of view range of common industrial vision detection systems, reducing the algorithm calculation burden, and improving the detection speed and stability.

[0069] In some examples, the step of obtaining the three-dimensional coordinate data of the surface of the tab 210 includes: Performing laser scanning on the reference area to obtain three-dimensional coordinate data of a plurality of sampling points; Using a statistical analysis method to eliminate noise points in the three-dimensional coordinate data; Generating a reference surface based on the data after eliminating noise points.

[0070] By using the above technical solutions, the statistical analysis effectively eliminates noise points to improve data accuracy, and the reference surface generated based on the fitting improves data reliability and consistency, and the overall process is efficient and highly automated.

[0071] In some examples, optionally, the statistical analysis method is a mean ± 3 times standard deviation criterion.

[0072] The mean ± 3 times standard deviation criterion is simple to calculate and easy to implement, can effectively identify and eliminate abnormal points that significantly deviate from the normal distribution, while maintaining the overall distribution characteristics of the data and improving the accuracy of the fitting reference surface.

[0073] In some examples, optionally, the step of determining the detection result of whether the tab 210 is cracked includes: when any one of the height difference criterion and the topography mutation criterion is satisfied, it is determined that the tab 210 is cracked.

[0074] In the above method, when the height difference between any measurement point in the to-be-detected analysis area and the reference surface exceeds a preset first threshold value (for example, in the range of 0.05-0.3 mm), the height difference criterion is triggered; or when the fitting slope of the topography change curve along the specified coordinate axis direction exceeds a second threshold value (for example, in the range of 10-100 dimensionless), the topography mutation criterion is triggered.

[0075] The two criteria respectively capture different defect characteristics from two physical dimensions of vertical displacement and surface continuity. As long as any one criterion is satisfied, the system determines that the tab 210 has a cracking defect.

[0076] The design advantage is that as long as any one criterion is triggered, a defect is reported, achieving double sensitivity to height abnormalities and topography mutations, which can reduce the possibility of missed detection, greatly improve the crack detection rate, and at the same time maintain the high efficiency and simplicity of the algorithm.

[0077] In some examples, optionally, the height difference criterion includes: the height difference between any point in the to-be-detected analysis area and the reference surface exceeds a preset first threshold value.

[0078] In the above detection method, the "height difference criterion" is used to determine whether there is a cracking defect in the to-be-detected analysis area, and is specifically defined as: the vertical distance (i.e., the height difference) between the surface height data of any point in the to-be-detected analysis area 2112 and the pre-set reference surface exceeds a preset first threshold value, then it is determined that the point is abnormal, and the tab 210 has a cracking, warping or other deformation defect.

[0079] The first threshold value is determined based on the characteristics of the tab 210 material, process tolerance and safety margin, for example, by statistically setting a reasonable upper limit value after experimentally determining the height fluctuation range of the normal tab 210. In some embodiments, the first threshold value can be 0.05 mm-0.3 mm.

[0080] The advantage of this criterion is that it can quantitatively evaluate the degree of local deformation of the tab 210 surface, which is sensitive to small cracks that may affect safety, and at the same time realizes automatic judgment through threshold comparison, avoiding subjective errors.

[0081] During implementation, surface height data can be obtained through three-dimensional laser scanning, structured light imaging or confocal sensors, and then compared with the reference surface through an algorithm to make point-by-point judgments. Finally, the distribution, number or area ratio of the exceeding points and other characteristics are summarized to further assist in determining the severity of the cracking.

[0082] The above-mentioned method can directly quantify welding defects by setting the first threshold of the height difference. When the deviation between the detection point and the reference plane exceeds the first threshold, typical defects such as cold welding or weld penetration can be quickly determined, which ensures detection sensitivity and avoids misjudgment, thereby improving detection efficiency and reliability.

[0083] In some examples, optionally, the morphology mutation criterion includes: a morphology mutation criterion along the first coordinate axis and / or a morphology mutation criterion along the second coordinate axis.

[0084] The first coordinate axis can be understood as the first direction X in the figure, and the second coordinate axis can be understood as the second direction Y in the figure, and the first direction X and the second direction Y intersect.

[0085] In some embodiments, the first direction X and the second direction Y may be horizontal directions perpendicular to each other, and the first direction X and the second direction Y are respectively perpendicular to the third direction Z.

[0086] The above method can more accurately capture crack defects in multiple directions through multi-coordinate axial morphology mutation detection, significantly improving the crack detection rate and detection reliability.

[0087] In some examples, optionally, the morphology mutation criterion is determined by: A linear fitting is performed on the morphology change curve along the specified coordinate axis in the detection and analysis area, and the fitting slope exceeds a second threshold.

[0088] The "morphological mutation criterion" is used to identify local morphological discontinuities caused by cracks within the area to be inspected and analyzed. This criterion is implemented by first selecting a coordinate axis direction associated with the geometric characteristics of the weld print area for morphological analysis. Specifically, when inspecting the short edges of the weld print area (usually corresponding to the two edges opposite each other in the first direction X), the curve f(X)=Z showing the variation of the Z coordinate value in the third direction with the X coordinate value in the first direction is analyzed and linearly fitted. Similarly, when inspecting the long edges of the weld print area (usually corresponding to the two edges opposite each other in the second direction Y), the curve f(Y)=Z showing the variation of the Z coordinate value in the third direction with the Y coordinate value in the second direction is analyzed.

[0089] When the tab 210 cracks, the surface morphology will have a step jump due to material fracture, at this time the fitting curve slope of the corresponding direction will increase significantly, theoretically close to infinity. In practical application, a reasonable second threshold value (which can be determined by experimental statistics according to actual process parameters) is set to determine whether the slope is out of limit, so as to determine whether there is a cracking defect.

[0090] The advantage of this criterion is that it can detect the cracking characteristics of different edge directions (short side / long side) of the welding mark area in a targeted manner. By reasonably selecting the coordinate axis direction, the morphology mutation caused by cracking can be effectively captured, improving the pertinence and accuracy of detection. In specific implementation, three-dimensional morphology measurement data can be combined for multi-directional scanning analysis along the X, Y and second directions. By comparing the abnormal conditions of the fitting slopes in each direction, comprehensive detection of different cracking defects can be achieved. In some embodiments, the second threshold value can be 10-100.

[0091] The above method quantifies the morphology mutation degree by linear fitting slope, which can accurately identify the characteristics of micro cracks, reduce the possibility of subjective misjudgment, and obtain objective and reliable detection results with adjustable sensitivity.

[0092] In combination with the accompanying Figure 3 In some examples, the first surface 310 of the adapter piece 300 selected for welding with the tab 210 is selected as the reference area, and the second surface 211 of the tab 210 facing away from the first surface 310 is selected as the detection analysis area 2112.

[0093] In some embodiments, the first surface 310 is the upper surface of the adapter piece 300, and the second surface 211 is the upper surface of the tab 210.

[0094] When the number of adapter pieces 300 and tabs 210 is multiple (for example, four tabs 210 and two adapter pieces 300, each adapter piece 300 has two convex structures, and each convex structure has one first surface 310), the number of first surfaces 310 and second surfaces 211 is multiple, and the number of first surfaces 310 is equal to the number of second surfaces 211.

[0095] In this embodiment, the reference area and the detection analysis area 2112 are designed separately. First, the reference surface is established on the welded first surface 310 (stress input side) of the adapter piece 300, and the detection area is set on the second surface 211 (stress output side) of the tab 210, which can accurately capture the real deformation of the tab 210 in the thickness direction caused by welding thermal stress, establish a direct correspondence between "stress source-deformation surface", and make the detection result directly reflect the mechanical influence of the welding process on the tab 210 body, avoiding the interference of composite deformation factors.

[0096] Secondly, the design in which the reference surface and the detection surface belong to different components effectively isolates the interference of the assembly tolerance of the adapter 300 (such as parallelism / gap) on the detection results. Even if there is an assembly deviation, the reference surface can still accurately represent the welding stress action benchmark, ensuring that the deformation detection data only contains the actual deformation of the tab 210 body.

[0097] In addition, the second surface 211 as a free end surface has a deformation amplification effect. Experimental data show that this design can increase the amplitude of the detection signal of micron-level cracking / warping by 40-60%, significantly improving the detection rate of early defects.

[0098] Of course, the reference area can also be other surfaces, such as the upper surface of the base 10. As long as it is a relatively fixed plane that can be captured by the three-dimensional scanning unit, it can be used as the reference area.

[0099] In some examples, optionally, after determining the welding quality of the tab, the tab crack detection method further includes: presenting the determination result of the welding quality of the tab on a display.

[0100] Presenting the judgment result of the welding quality of the tab on the display is to present the judgment result in a visual manner. The judgment result of cracking or not cracking can be directly displayed on a display device (not shown in the figure) electrically connected to the tab crack detection device 30 described below, or the defect position can be marked on the three-dimensional model of the tab using the display device.

[0101] The judgment results of the welding quality of the tab are presented in a visual manner, making it convenient for staff to directly obtain the judgment results using a display device.

[0102] Combined with attachment Figure 2 As shown, the embodiment of the present application also provides a tab crack detection device 30, including a three-dimensional scanning unit 31, a data processing unit 32 and a judgment unit 33: the three-dimensional scanning unit 31 is used to obtain three-dimensional coordinate data of multiple reference areas and obtain three-dimensional coordinate data of the surface of the tab 210; the data processing unit 32 is used to construct a reference plane through the three-dimensional coordinate data of multiple reference areas, and is used to compare the height characteristic difference between the surface of the tab 210 and the reference plane to determine the analysis area 2112 to be detected of the tab 210, and is also used to obtain the height difference criterion and morphology mutation criterion of the analysis area to be detected compared with the reference plane; the judgment unit 33 is used to determine the detection result of whether the tab 210 is cracked through at least one of the height difference criterion and the morphology mutation criterion.

[0103] The three-dimensional scanning unit 31 can be an optical measurement module in a 3D profiler, a laser scanner, or a laser tracker. For example, the optical measurement module in the 3D profiler can include a structured light projector (generating a fringe grating pattern), a high-resolution CCD camera group, and a precision moving guide rail (achieving XYZ three-axis scanning positioning), etc. The unit collects three-dimensional point cloud data of the first surface 310 (reference area) of the adapter piece 300 and the second surface 211 of the tab 210 through phase shift method or laser triangulation principle.

[0104] The data processing unit 32 can be a built-in processor in the 3D profiler, or can be jointly constituted by the built-in processor (such as Intel Xeon embedded industrial computer) in the 3D profiler and the MES system (such as Siemens SIMATIC IT).

[0105] The entity of the judgment unit 33 can be a quality judgment server (such as Dell PowerEdge R740xd) of the MES system, which includes a rule engine, a real-time database, and a visualization interface. The unit receives the height difference (ΔZ) and topography slope (K) data stream output by the data processing unit 32, executes the preset judgment logic (IF-THEN rule), and sends the qualified / unqualified signal to the production line PLC through the PROFINET interface.

[0106] The above structure designs the tab cracking detection device 30 to include the three-dimensional scanning unit 31, the data processing unit 32, and the judgment unit 33. The three-dimensional scanning unit 31 can quickly obtain high-precision surface topography data. The data processing unit 32 effectively eliminates assembly errors by constructing a reference surface, and ensures the comprehensiveness of crack detection by combining the height difference and topography mutation double criteria. The judgment unit 33 uses algorithms to achieve more accurate defect judgment, and has better detection efficiency and accuracy compared with manual detection.

[0107] The above, the accompanying drawings and the Figure 6 and the accompanying drawings and the Figure 7As shown, the embodiment of the present application also provides a tab welding device 100, including a base 10, a welding device 20 and a tab crack detection device 30 as described above, wherein the base 10 is used to place the electrode assembly 200 and the adapter 300; the welding device 20 is used to weld the tab 210 and the adapter 300 located on the base 10; the tab crack detection device 30 includes a laser scanner and a processor, the laser scanner is used to obtain three-dimensional coordinate data of multiple reference areas to construct a reference plane, the processor is used to obtain three-dimensional coordinate data of the surface of the tab 210, and based on the three-dimensional coordinate data, compare the height characteristic difference between the surface of the tab 210 and the reference plane to determine the analysis area 2112 to be detected of the tab 210, the processor is also used to compare the height difference and morphology of the analysis area 2112 to be detected and the reference plane, and determine the detection result of whether the tab 210 is cracked based on at least one of the height difference criterion and the morphology mutation criterion.

[0108] The laser scanning device includes the above-mentioned three-dimensional scanning unit 31 , and the processor may include the above-mentioned data processing unit 32 and judgment unit 33 .

[0109] The base 10 is used to provide a welding working surface and a welding quality inspection working surface for the tab 210. The structural form of the base 10 is not limited as long as it has a welding working surface and a welding quality inspection working surface.

[0110] like Figure 6 As shown, during welding, the welding device 20 welds the tab 210 and the adapter 300. After welding, the welding device 20 can be transferred to a position away from the tab 210 by a structure such as a robotic arm. Figure 7 The 3D profilometer of the tab crack detection device 30 is moved above the tab 210 to perform welding quality inspection.

[0111] By using the tab crack detection device 30 to detect the welding quality of the tab 210 during the welding process, the welding quality of the tab 210 can be monitored in real time, reducing the possibility of defective products flowing into the next process; and the detection data can be directly fed back to adjust the welding parameters to achieve process closed-loop control.

[0112] In some examples, optionally, the tab welding device 100 further includes a vibration absorber 40 , and the base 10 is mounted on the vibration absorber 40 .

[0113] The shock absorber 40 may be a spring shock absorber, or a rubber shock absorber, an air spring shock absorber, a hydraulic shock absorber, a magnetorheological shock absorber, a wire rope shock absorber, etc., which are not listed in detail in this embodiment.

[0114] The base 10 is mounted on the vibration absorber 40 to reduce vibration of the base 10 during welding, thereby improving the testing accuracy of the tab crack detection device 30 .

[0115] In addition, the embodiment of the present application provides a battery production system, which comprises a transfer device (not shown in the figure) and the tab welding device 100 of the above technical solution, and the transfer device is used for transferring the cracked tab 210 detected by the tab cracking detection device 30 of the tab welding device 100 to a defective product area (not shown in the figure).

[0116] The transfer device can be a carrying robot or other structures capable of transporting electrode assemblies.

[0117] The above description is only a summary of the technical solutions of the present application, in order to more clearly understand the technical means of the present application, the content of the specification can be implemented, and in order to make the above and other purposes, characteristics and advantages of the present application more obvious and easy to understand, the following specific embodiments of the present application are described.

[0118] Please refer to the accompanying drawings Figure 1As shown, the electrode tab 210 cracking detection method provided by the embodiments of the present application includes the following steps: obtaining three-dimensional coordinate data of a plurality of reference areas to construct a reference surface; obtaining three-dimensional coordinate data of the surface of the electrode tab 210, determining the to-be-detected analysis area 2112 of the electrode tab 210 based on the height characteristic difference between the surface of the electrode tab 210 and the reference surface, and comparing the height difference and the topography of the to-be-detected analysis area 2112 and the reference surface, and determining the detection result of whether the electrode tab 210 cracks based on at least one of the height difference criterion and the topography mutation criterion. The step of determining the to-be-detected analysis area 2112 of the electrode tab 210 based on the height characteristic difference between the surface of the electrode tab 210 and the reference surface includes: determining the spatial position range of the welding mark area 2111 of the electrode tab 210 by comparing the height characteristic difference between the surface of the electrode tab 210 and the reference surface; and extending a preset boundary in the first direction X and the second direction Y according to the spatial position range of the welding mark area 2111 to form the to-be-detected analysis area 2112, the first direction X and the second direction Y intersecting and being parallel to the surface of the electrode tab 210. The width of the preset boundary extended in the first direction X is 3mm to 10mm, and / or the width of the preset boundary extended in the second direction Y is 3mm to 10mm. The step of obtaining the three-dimensional coordinate data of the surface of the electrode tab 210 includes: performing laser scanning on the reference area to obtain three-dimensional coordinate data of a plurality of sampling points; using a statistical analysis method to remove noise points in the three-dimensional coordinate data; and generating the reference surface based on the data after removing the noise points. The statistical analysis method is the mean ± 3 standard deviation criterion. The step of determining the detection result of whether the electrode tab 210 cracks includes: determining that the electrode tab 210 cracks when any one of the height difference criterion and the topography mutation criterion is met. The height difference criterion includes: the height difference between any point in the to-be-detected analysis area 2112 and the reference surface exceeds a preset first threshold. The topography mutation criterion includes a topography mutation criterion along the first coordinate axis direction and / or a topography mutation criterion along the second coordinate axis direction. The topography mutation criterion is determined by: performing linear fitting on the topography change curve along the specified coordinate axis direction in the to-be-detected analysis area 2112, and the slope of the fitting exceeds a second threshold. The first surface 310 of the adapter piece 300 used for welding with the electrode tab 210 is selected as the reference area, and the second surface 211 of the electrode tab 210 away from the first surface 310 is selected as the to-be-detected analysis area 2112. After determining the detection result of whether the electrode tab 210 cracks, the electrode tab 210 cracking detection method further includes: presenting the judgment result of the welding quality of the electrode tab 210 on the display.

[0119] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0120] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not intended to limit the same; although the present application has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacements for some of the technical features, but these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for detecting tab cracking, characterized in that: The following steps are involved: Acquiring three-dimensional coordinate data of a plurality of reference areas to construct a reference surface; Acquiring three-dimensional coordinate data of the tab surface, and determining a to-be-detected analysis area of ​​the tab by comparing a height characteristic difference between the tab surface and the reference plane based on the three-dimensional coordinate data; The height difference and morphology of the to-be-detected analysis area and the reference surface are compared, and a detection result of whether the tab is cracked is determined based on at least one of a height difference criterion and a morphology mutation criterion.

2. The tab crack detection method according to claim 1, characterized in that: The step of determining the to-be-detected analysis area of ​​the tab by comparing the height characteristic difference between the tab surface and the reference plane based on the three-dimensional coordinate data comprises: Determining the spatial position range of the welding mark area of ​​the tab by comparing the height feature difference between the tab surface and the reference plane; The analysis area to be detected is formed by extending the preset boundaries in a first direction and a second direction according to the spatial position range of the weld mark area, and the first direction and the second direction intersect and are respectively parallel to the surface of the tab.

3. The tab crack detection method according to claim 2, characterized in that: The width of the preset boundary is extended in the first direction by 3 mm to 10 mm, and / or the width of the preset boundary is extended in the second direction by 3 mm to 10 mm.

4. The tab crack detection method according to claim 1, characterized in that: The step of obtaining three-dimensional coordinate data of the tab surface comprises: Performing laser scanning on the reference area to obtain the three-dimensional coordinate data of a plurality of sampling points; Using statistical analysis methods to eliminate noise points in the three-dimensional coordinate data; The reference surface is generated by fitting based on the data after noise points are eliminated.

5. The tab crack detection method according to claim 4, characterized in that: The statistical analysis method was the mean ± 3 times the standard deviation criterion.

6. The tab crack detection method according to claim 1, characterized in that: The step of determining the detection result of whether the tab is cracked comprises: When any one of the height difference criterion and the shape mutation criterion is satisfied, it is determined that the tab is cracked.

7. The tab crack detection method according to claim 6, characterized in that: The height difference criterion includes: the height difference between any point in the to-be-detected analysis area and the reference plane exceeds a preset first threshold.

8. The tab crack detection method according to claim 6, characterized in that: The morphology mutation criterion includes a morphology mutation criterion along the first coordinate axis and / or a morphology mutation criterion along the second coordinate axis.

9. The tab crack detection method according to claim 8, characterized in that: The morphology mutation criterion is determined by performing a linear fit on the morphology change curve along the specified coordinate axis in the to-be-detected analysis area, and the slope of the fit exceeds a second threshold.

10. The tab crack detection method according to any one of claims 1 to 9, characterized in that: The first surface of the adapter plate used for welding with the tab is selected as the reference area, and the second surface of the tab away from the first surface is selected as the to-be-detected analysis area.

11. The tab crack detection method according to any one of claims 1 to 9, characterized in that: After determining the detection result of whether the tab is cracked, the tab crack detection method further includes: presenting the judgment result of the welding quality of the tab on a display.

12. A tab crack detection device, characterized in that: include: A three-dimensional scanning unit, used to obtain three-dimensional coordinate data of multiple reference areas and obtain three-dimensional coordinate data of the tab surface; a data processing unit, configured to construct a reference plane using three-dimensional coordinate data of a plurality of reference areas, and to determine a to-be-detected and analyzed area of ​​the tab by comparing the height characteristic difference between the tab surface and the reference plane, and to obtain a height difference criterion and a morphology mutation criterion for the to-be-detected and analyzed area compared to the reference plane; as well as A judgment unit is used to determine a detection result of whether the tab is cracked based on at least one of the height difference criterion and the shape mutation criterion.

13. A tab welding device, characterized in that: include: A base for placing the electrode assembly and adapter; A welding device for welding the tab connected to the electrode assembly and the adapter plate on the base; as well as A tab crack detection device includes a laser scanner and a processor. The laser scanner is used to obtain three-dimensional coordinate data of multiple reference areas to construct a reference plane. The processor is used to obtain three-dimensional coordinate data of the tab surface and determine the tab's to-be-detected analysis area by comparing the height characteristic difference between the tab surface and the reference plane based on the three-dimensional coordinate data. The processor is also used to compare the height difference and morphology between the to-be-detected analysis area and the reference plane, and determine a detection result of whether the tab is cracked based on at least one of a height difference criterion and a morphology mutation criterion.

14. The tab welding equipment according to claim 13, characterized in that: The tab welding equipment further includes a vibration damper, and the base is mounted on the vibration damper.

15. A battery production system, characterized in that: The method comprises a transfer device and the tab welding device according to claim 13 or 14, wherein the transfer device is used to transfer the cracked tabs detected by the tab crack detection device of the tab welding device to a defective product area.

Images