Positioning method, device and system for welding of lithium battery cover plate

Abstract

The invention discloses a lithium battery cover plate welding positioning method, device and system, and the method comprises the steps: obtaining an original collection image of a to-be-welded cover plate, and extracting an ROI region from the original collection image through an image processing algorithm, so as to obtain to-be-processed image data; a first to-be-welded edge and a second to-be-welded edge are extracted from the to-be-processed image data, the slope of the first to-be-welded edge and the slope of the second to-be-welded edge are calculated, and whether the splicing edge of the to-be-welded frame deviates or not is determined; an edge grabbing track blind area is eliminated; edge grabbing misjudgment fool-proofing is carried out; detecting skew deformation of the product; and interference characteristics are automatically compatible. According to the method, the welding quality problems such as edge grabbing misjudgment and welding line deflection can be completely solved, the welding air tightness of the battery cell is guaranteed, automatic compatibility of edge abnormal points can be achieved, the rejection rate of products is reduced, and the yield of the products is improved.

Description

Technical Field

[0001] The present invention relates to the field of lithium battery technology, and in particular to a positioning method, device and system for welding a lithium battery cover plate. Background Art

[0002] Lithium batteries are widely used in laptop computers, digital products, mobile communications, etc. due to their advantages such as high operating voltage, high energy density, long cycle life, and no memory effect.

[0003] With the rapid development of electronic devices, people have higher requirements for the safety and capacity of lithium batteries. In order to meet the requirements of improving battery capacity and battery safety, the batteries of 3C digital products have gradually developed from the original soft-pack structure to the steel shell structure. The steel shell battery mentioned in the present invention includes a bottom plate, a middle frame, a cover plate, a pole and a sealing nail structure, which can effectively improve the internal space utilization of the battery and increase the battery capacity. However, due to the thin thickness of the cover plate and the middle frame, deformation is easy to occur during the processing project. At present, the industry mostly uses mechanical positioning for the laser welding part of the cover plate, and a small number of leading companies also use visual positioning to guide welding, but there are problems such as poor consistency of weld trajectory, weld deviation out of the shell, weld cracking of the battery cell, poor anti-interference, etc., resulting in poor air tightness of the battery cell, easy to cause leakage, and seriously affect the performance of the battery cell. Specifically, firstly, the blind area of ​​the weld trajectory is too large, and the weld contour position cannot match the actual contour of the frame and cover; secondly, there is a lack of an anti-misjudgment mechanism for edge grabbing, and the edge grabbing fitting trajectory is skewed and no NG alarm is given, resulting in welding offset or welding on the fixture; finally, the robustness is poor, and the influence of edge burrs or foreign matter on the welding trajectory will not be automatically eliminated. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a positioning method, device and system for welding a lithium battery cover.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a positioning method for welding a lithium battery cover plate, obtaining an original captured image of the cover plate to be welded, and using an image processing algorithm to extract a ROI area from the original captured image to obtain image data to be processed; Extracting the first edge to be welded and the second edge to be welded from the image data to be processed, calculating the slopes of the first edge to be welded and the second edge to be welded, and determining whether the splicing edge of the frame to be welded is offset; Eliminate the blind spot of the edge grabbing track. If the edge grabbing track is a straight line area, establish a linear relationship between the number of edge grabbing points n1 and the length of the straight line area L1 of the edge grabbing, △L1=L1 / (n1-1), and △L1 is not greater than 3 to 5 times the single pixel accuracy, the single pixel accuracy is 0.006mm / pixel, △L≤0.03 mm, and eliminate the blind spot of the straight edge grabbing; If the edge grabbing track is an arc area, establish a linear relationship between the number of edge grabbing points n2 and the arc length L2, △L2=L2 / (n2-1), and △L2 is not greater than 3 to 5 times the single pixel accuracy, the single pixel accuracy is 0.006mm / pixel, △L≤0.03mm, to eliminate the arc edge grabbing blind spot; Prevent mistakes when grabbing the edge; Product skew and deformation detection; Interference features are automatically compatible.

[0006] Further, extracting the first edge to be welded and the second edge to be welded from the image data to be processed, calculating the slopes of the first edge to be welded and the second edge to be welded, and determining whether the splicing edge of the frame to be welded is offset, including: The edge of the metallic frame is extracted using an edge extraction algorithm, two lines set in the middle of the image are determined as the first edge to be welded and the second edge to be welded, and the difference in slope between the first edge to be welded and the second edge to be welded is calculated; If the absolute value of the difference is less than the predetermined threshold, it is confirmed that the welding of the cover plate to be welded has not been offset, the welding of the cover plate to be welded is qualified, and subsequent welding work can be performed; If the absolute value of the difference reaches the predetermined threshold, it is confirmed that the welding of the cover plate to be welded has been offset, and the welding of the cover plate to be welded is unqualified. An alarm can be given by means of text, sound, light, etc., or other robots can be instructed to move the cover plate to be welded to the rework or unqualified product station, and manual correction can be performed using a jig, and then the welding positioning work can be performed again after correction.

[0007] Furthermore, the edge grabbing misjudgment prevention method includes: If the edge grabbing trajectory is a straight line area, the angle difference between the welding center line fitted by the edge grabbing and the actual angle θ of the X-axis is used to determine whether there is a misjudgment of the edge grabbing. ≤ It is judged that there is no misjudgment, and the preferred If there is a misjudgment, an alarm or automatic compatibility mutation point is required; If the edge grabbing trajectory is an arc area, use the inner and outer wall center distance △R and the shell width W solved point by point to determine whether there is a misjudgment. If there is a misjudgment, an alarm prompt or automatic compatibility mutation point is required.

[0008] Furthermore, the product skew deformation detection includes: Grab the straight edges of the inner and outer walls, and then find the angles θ_inside and θ_outside where the two adjacent sides intersect to determine whether they meet the requirements of the preset threshold angle and whether the product is skewed or deformed.

[0009] Furthermore, the interference features are automatically compatible, including: If the edge grabbing trajectory is a straight line area, the straight line correlation algorithm is used to automatically fit the ideal welding points of burrs, interference features and other points; If the edge grabbing trajectory is an arc area, the arc fitting analytical algorithm is used to automatically fit the ideal welding points of burrs, interference features and other points.

[0010] In a second aspect, the present invention provides a positioning device for welding a lithium battery cover plate, comprising: A preprocessing unit is used to obtain image data to be processed of a cover plate to be welded, wherein the cover plate to be welded includes a first side to be welded and a second side to be welded; capture a first endpoint and a second endpoint of the first side to be welded from the image data to be processed, and capture a third endpoint and a fourth endpoint of the second side to be welded from the image data to be processed, wherein the first endpoint is adjacent to the third endpoint, and the second endpoint is adjacent to the fourth endpoint; determine the midpoint coordinates of the first endpoint and the third endpoint to obtain a first midpoint coordinate, and determine the midpoint coordinates of the second endpoint and the fourth endpoint to obtain a second midpoint coordinate; The trajectory positioning unit is used to determine the welding start coordinates and the welding end coordinates according to the first midpoint coordinates, the second midpoint coordinates and a preset welding offset.

[0011] In a third aspect, the present invention provides a computer-readable storage medium, The computer-readable storage medium stores at least one program, and the at least one program is loaded and executed by the processor to implement the positioning method for welding a lithium battery cover plate as described in any one of claims 1 to 6.

[0012] In a fourth aspect, the present invention provides a lithium battery cover plate welding positioning system, comprising: an image acquisition device, a welding device, and the welding positioning device as described above; The image acquisition device is used to acquire the original acquired image of the welding cover plate, and send the image of the cover plate to be welded to the welding cover plate positioning device; The welding positioning device is used to analyze and process the original collected image to obtain the welding start coordinates and the welding end coordinates, and provide the welding start coordinates and the welding end coordinates to the welding device; The welding device is used to weld the cover plate according to the welding start coordinates and the welding end coordinates.

[0013] In summary, the beneficial effects of the present invention are: It can completely solve welding quality problems such as misjudgment of edge grasping and skewed welds, ensure the welding airtightness of the battery cell, and can automatically compatibility with abnormal edge points, reduce product scrap rate and improve product yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A schematic diagram of the slope of the first side to be welded and the slope of the second side to be welded in one embodiment of the present invention; Figure 2 A schematic diagram of the slope of the first side to be welded and the slope of the second side to be welded in one embodiment of the present invention; Figure 3 A schematic diagram of eliminating the blind area of ​​the track by grasping the straight edge in one embodiment of the present invention; Figure 4 A schematic diagram of eliminating the blind area of ​​the trajectory by grasping the edge of an arc segment in one embodiment of the present invention; Figure 5 A schematic diagram of capturing the coordinates of the contour points of the inner and outer walls of a shell according to an embodiment of the present invention; Figure 6 A schematic diagram of fitting the shell centerline point coordinates as the basic coordinates of the welding trajectory in one embodiment of the present invention; Figure 7 A schematic diagram of realizing double weld seam trajectories or multiple weld seam trajectories according to welding trajectory basic coordinates in one embodiment of the present invention; Figure 8 It is a schematic diagram of judging whether the housing and the cover plate are misaligned in one embodiment of the present invention. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] See also Figure 1-Figure 4 In a first aspect, the present invention provides a positioning method for welding a lithium battery cover plate, comprising the following steps: Step 101, obtaining an original captured image of the cover plate to be welded, and extracting a ROI region from the original captured image using an image processing algorithm to obtain image data to be processed; Among them, the extraction of ROI (region of interest) area can be achieved by processing the original data acquisition image through a predetermined image input processing algorithm or training model. This application does not make specific limitations on this, so as to exclude other irrelevant features of the cover plate to be welded, such as the environment, fixtures, surrounding dirt, foreign matter, etc., to improve the efficiency and accuracy of subsequent image processing related to the cover plate to be welded, and reduce unnecessary calculations and interference problems caused by irrelevant features.

[0017] Step 102, extracting the first edge to be welded and the second edge to be welded from the image data to be processed, calculating the slopes of the first edge to be welded and the second edge to be welded, and determining whether the splicing edges of the frame to be welded are offset; Specifically, the edge extraction algorithm may be used to extract the edge of the metallic frame, and two lines disposed in the middle of the image may be determined as the first edge to be welded and the second edge to be welded.

[0018] In one example, the specific implementation of this step can be: calculating the difference in slope between the first edge to be welded and the second edge to be welded; if the absolute value of the difference is less than a predetermined threshold, it is confirmed that the welding of the cover plate to be welded has not shifted, indicating that the welding of the cover plate to be welded is qualified and subsequent welding work can be carried out, wherein the predetermined threshold can be set by the technician based on experience.

[0019] Furthermore, if the absolute value of the difference reaches a predetermined threshold, it is confirmed that the welding of the cover plate to be welded is offset, and the welding of the cover plate product to be welded is unqualified. An alarm can be given by means of text, sound, light, etc., or other robots can be instructed to move the cover plate to be welded to a work station for rework or unqualified products, and manual correction can be performed using a jig, and then the welding positioning work can be performed again after correction.

[0020] Furthermore, assuming that the slope of the first edge to be welded is K1 and the slope of the second edge to be welded is K2, if the absolute value of the difference reaches a predetermined threshold, the same x point at the welding point is used, and according to the equations of the straight lines on both sides y1=k1*x1+b1 and y2=k2*x2+b2, y1 and y2 are calculated to evaluate whether there is a step difference, and then determine whether the welding is offset.

[0021] Step 103, eliminating the blind area of ​​the edge grabbing track; Specifically, if the edge grabbing track is a straight line area, a linear relationship is established between the number of edge grabbing points n1 and the length of the edge grabbing straight line area L1, △L1=L1 / (n1-1), and △L1 is not greater than 3 to 5 times the single pixel accuracy, the single pixel accuracy is 0.006mm / pixel, △L≤0.03 mm, and the straight edge grabbing blind area is eliminated; If the edge grabbing track is an arc area, establish a linear relationship between the number of edge grabbing points n2 and the arc length L2, △L2=L2 / (n2-1), and △L2 is not greater than 3 to 5 times the single pixel accuracy, the single pixel accuracy is 0.006mm / pixel, △L≤0.03mm, to eliminate the arc edge grabbing blind spot; Step 104, preventing misjudgment of edge grabbing; Specifically, if the edge grabbing trajectory is a straight line area, the shell width W and the angles θ_outer and θ_inner formed by the outer wall and the inner wall are solved point by point using the corresponding points on the outer wall and the inner wall to determine whether there is a misjudgment in the edge grabbing. If there is a misjudgment, an alarm prompt or automatic compatibility mutation point is required; if the edge grabbing trajectory is an arc area, the inner and outer wall center distance △R and the shell width W solved point by point are used to determine whether there is a misjudgment. If there is a misjudgment, an alarm prompt or automatic compatibility mutation point is required; Step 105, product skew deformation detection; Specifically, the least square method is used to capture the straight edges of the inner and outer walls, and then the angles θ_inside and θ_outside where the two adjacent sides intersect are calculated to determine whether they meet the requirements of the preset threshold angle and whether the product is skewed or deformed; Step 106: The interference features are automatically compatible.

[0022] Specifically, if the edge grabbing trajectory is a straight line area, a straight line correlation algorithm is used to automatically fit the ideal welding points of burrs, interference features and other points; if the edge grabbing trajectory is an arc area, an arc fitting analytical algorithm is used to automatically fit the ideal welding points of burrs, interference features and other points.

[0023] It can be understood that, in one embodiment, a positioning method for welding a lithium battery cover is provided, comprising the following steps: The first step is to use the image processing algorithm to extract the ROI area of ​​the cover plate to be welded from the shell of the battery cell to increase the proportion of effective pixels; In the second step, in the ROI area, the three-segment slope algorithm is used to obtain the best straight line edges on both sides of the weld, and the corresponding best edge slopes k1 and k2 are obtained to determine whether the weld is skewed; if the difference between k1 and k2 meets the set slope threshold difference, the same x point at the weld is used, combined with the straight line equations y1=k1*x1+b1 and y2=k2*x2+b2 on both sides, to calculate y1 and y2, and evaluate whether there is a step difference (step difference ≤40um), to determine whether the weld is offset or the product is severely deformed, and if it is deformed, it is NG, such as Figure 1 , Figure 2 As shown; The third step is to extract the edge contour by using the least square method for the straight area part in the cover plate shell area to be welded, establish a linear relationship between the number of edge grabbing points n1 and the length of the straight area L, the point spacing △L=L / (n1-1), and △L is not greater than 3 to 5 times the single pixel accuracy, and eliminate the straight edge grabbing blind area; for the arc area, use the least square method to extract the edge contour, establish a linear relationship between the number of edge grabbing points n2 and the center angle θ of the arc, divide the center angle into n2-1 parts, and the angle distance between points △θ=θ / (n2-1) is not greater than 3 to 5 times the single pixel accuracy, and eliminate the arc grabbing blind area, such as Figure 3 As shown; The fourth step is to determine whether there is a misjudgment or foreign matter such as burrs in the edge grabbing at the current point by using the angle difference θ_outer and θ_inner between the corresponding points of the outer wall and the inner wall between the n1 points of the edge grabbing point by point to determine whether there is a misjudgment or foreign matter such as burrs in the edge grabbing at the current point. If so, an alarm is required or the mutation point is automatically compatible. In the arc area, the inner and outer wall center distance △R and the shell width W calculated point by point are used to determine whether there is a misjudgment. If so, an alarm is required or the mutation point is automatically compatible. Figure 4 As shown; Step 5: In the straight line area, use the least square method to capture the straight line edges of the inner and outer walls of the shell, and then calculate the angles θ_inside and θ_outside (normal angle range 90°±0.26°) where the two adjacent sides intersect to determine whether they meet the requirements of the preset threshold angle and whether the product is skewed or deformed; Step 6: For the abnormal points or misjudged points, there are two cases: ① In the straight line area, the straight line correlation algorithm is used to automatically fit the ideal welding points of burrs, interference features and other points; ② In the arc area, the arc fitting analysis algorithm is used to automatically fit the ideal welding points of burrs, interference features and other points; Step 7: Repeat steps 2 to 4 to capture the contour point coordinates of the inner and outer wall edges of the entire battery shell area by area, including 400 points in the straight area and 200 points in the arc area, for a total of 2,400 point coordinates. Figure 5 As shown; In the eighth step, according to the 2400 point coordinates of the outer contour of the battery shell and the 2400 point coordinates of the inner contour of the shell, use X_Middle=X_Out+X_In, Y_Middle=Y_Out+Y_In to fit the 2400 point coordinates of the shell centerline as the basic coordinates of the welding trajectory, such as Figure 6 shown.

[0024] In the ninth step, according to the basic coordinates of the welding trajectory of the center line of the shell, the basic coordinates of the welding trajectory are offset inward or outward by one or more offsets to obtain two or more sets of welding trajectory point coordinates, so as to realize the welding of double weld trajectories or multiple weld trajectories and ensure the air tightness of the product. Figure 7 As shown; The tenth step is to position the cover plate to the corresponding position of the steel shell battery cell shell by positioning and loading, and determine whether the cover plate is in place, specifically including: first, using the least squares method to obtain the shell edge L1 from the outside to the inside; secondly, using the least squares method at the same position to obtain the cover plate edge L2 from the inside to the outside; finally, using the line-to-line distance solution algorithm to calculate the distance Width between L1 and L2, compare the Width with the set distance threshold, and determine whether the shell and the cover plate are misaligned. If they are misaligned, they are not welded. Figure 8 shown.

[0025] In a second aspect, the present application also discloses a positioning device for welding a lithium battery cover plate, comprising: a preprocessing unit and a trajectory positioning unit.

[0026] a preprocessing unit, configured to obtain image data to be processed of a cover plate to be welded, the cover plate to be welded comprising a first side to be welded and a second side to be welded; capture a first endpoint and a second endpoint of the first side to be welded from the image data to be processed, and capture a third endpoint and a fourth endpoint of the second side to be welded from the image data to be processed, wherein the first endpoint is adjacent to the third endpoint, and the second endpoint is adjacent to the fourth endpoint; determine the midpoint coordinates of the first endpoint and the third endpoint to obtain a first midpoint coordinate, and determine the midpoint coordinates of the second endpoint and the fourth endpoint to obtain a second midpoint coordinate; The trajectory positioning unit is used to determine the welding start coordinates and the welding end coordinates according to the first midpoint coordinates, the second midpoint coordinates and the preset welding offset.

[0027] In a third aspect, the present application further discloses a computer-readable storage medium, in which at least one program is stored, and the at least one program is loaded and executed by a processor to implement the above-mentioned positioning method for lithium battery cover welding.

[0028] In a fourth aspect, the present application also discloses a positioning system for a lithium battery welding cover plate, comprising: an image acquisition device, a welding device and a welding positioning device; the image acquisition device is used to acquire the original acquired image of the welding cover plate, and send the cover plate image to the cover plate welding positioning device; the welding positioning device is used to analyze and process the original acquired image to obtain the welding start coordinates and the welding end coordinates, and provide the welding start coordinates and the welding end coordinates to the welding device; the welding device is used to weld the cover plate according to the welding start coordinates and the welding end coordinates.

[0029] The positioning method, device and system of the lithium battery cover welding of the present invention realizes automatic and precise laser online welding through image acquisition, image processing, least squares method, straight line correlation algorithm and arc fitting analytical algorithm, and effectively solves the technical problem of leakage caused by abnormal welding trajectory of the battery cover. The positioning method, device and system of the lithium battery cover welding of the present invention, on the one hand, by reducing the welding point coordinate spacing, the original straight edge point spacing of 9.8mm is reduced to 0.22mm, and the arc point spacing is reduced from 45° to 0.45°, eliminating the trajectory blind area; on the other hand, the straight edge evaluates whether the edge is misjudged by slope comparison, and the arc edge judges whether the edge is misjudged by the inner and outer center distances and the arc radius; on the other hand, the straight edge adds a straight line correlation algorithm to realize abnormal point judgment and automatically eliminate edge interference features, and the arc edge uses the arc fitting analytical method to judge and automatically eliminate the arc edge interference features, thereby improving the algorithm robustness and weld quality.

[0030] The positioning method, device and system for lithium battery cover welding of the present invention are suitable for steel shell battery cells of various shapes. The cover welding of the battery cell is automatically positioned by machine vision technology to avoid product airtightness problems caused by trajectory deviation. Moreover, before positioning, machine vision technology is used to determine whether there are steps or deformations in the battery cell shell. When it is determined that there is no deformation, the welding trajectory points are acquired, which can avoid welding in the case of abnormal shell that causes product scrapping, further improve the quality of the weld, and improve the technical problems of low positioning accuracy and poor weld quality in the welding trajectory in the prior art.

[0031] The positioning method, device and system for welding of lithium battery cover plates of the present invention include obtaining the original captured image of the cover plate to be welded, extracting the ROI area from the original captured image using an image processing algorithm to obtain the image data to be processed; extracting the first edge to be welded and the second edge to be welded from the image data to be processed, calculating the slope of the first edge to be welded and the second edge to be welded, and determining whether the splicing edge of the frame to be welded is offset; eliminating the blind area of ​​the edge grasping track; preventing misjudgment of edge grasping; detecting product skew and deformation; and automatically compatibility of interference features. The present invention can completely solve welding quality problems such as misjudgment of edge grasping and skewed welds, ensure the welding airtightness of the battery core, and can realize automatic compatibility of edge abnormal points, reduce the scrap rate of products, and improve the yield rate of products.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A positioning method for welding a lithium battery cover plate, characterized in that: The following steps are involved: Obtain the original acquired image of the cover plate to be welded, and use the image processing algorithm to extract the ROI area from the original acquired image to obtain the image data to be processed; Extracting the first edge to be welded and the second edge to be welded from the image data to be processed, calculating the slopes of the first edge to be welded and the second edge to be welded, and determining whether the splicing edge of the frame to be welded is offset; Eliminate the blind spot of the edge grabbing track. If the edge grabbing track is a straight line area, establish a linear relationship between the number of edge grabbing points n1 and the length of the straight line area L1 of the edge grabbing, △L1=L1 / (n1-1), and △L1 is not greater than 3 to 5 times the single pixel accuracy, the single pixel accuracy is 0.006mm / pixel, △L≤0.03 mm, and eliminate the blind spot of the straight edge grabbing; If the edge grabbing track is an arc area, establish a linear relationship between the number of edge grabbing points n2 and the arc length L2, △L2=L2 / (n2-1), and △L2 is not greater than 3 to 5 times the single pixel accuracy, the single pixel accuracy is 0.006mm / pixel, △L≤0.03 mm, to eliminate the arc edge grabbing blind spot; Prevent mistakes when grabbing the edge; Product skew and deformation detection; Interference features are automatically compatible.

2. The method according to claim 1, characterized in that Extracting a first edge to be welded and a second edge to be welded from the image data to be processed, calculating the slopes of the first edge to be welded and the second edge to be welded, and determining whether the splicing edge of the frame to be welded is offset, including: The edge of the metallic frame is extracted using an edge extraction algorithm, two lines set in the middle of the image are determined as the first edge to be welded and the second edge to be welded, and the difference in slope between the first edge to be welded and the second edge to be welded is calculated; If the absolute value of the difference is less than the predetermined threshold, it is confirmed that the welding of the cover plate to be welded has not been offset, the welding of the cover plate to be welded is qualified, and subsequent welding work can be performed; If the absolute value of the difference reaches the predetermined threshold, it is confirmed that the welding of the cover plate to be welded has been offset, and the welding of the cover plate to be welded is unqualified. An alarm can be given by means of text, sound, light, etc., or other robots can be instructed to move the cover plate to be welded to the rework or unqualified product station, and manual correction can be performed using a jig, and then the welding positioning work can be performed again after correction.

3. The method according to claim 1, characterized in that The edge grabbing misjudgment prevention method includes: If the edge grabbing trajectory is a straight line area, the angle difference between the welding center line fitted by the edge grabbing and the actual angle θ of the X-axis is used to determine whether there is a misjudgment of the edge grabbing. ≤ It is judged that there is no misjudgment, and the preferred If there is a misjudgment, an alarm or automatic compatibility mutation point is required; If the edge grabbing trajectory is an arc area, use the inner and outer wall center distance △R and the shell width W solved point by point to determine whether there is a misjudgment. If there is a misjudgment, an alarm prompt or automatic compatibility mutation point is required.

4. The method according to claim 1, characterized in that: The product skew deformation detection includes: Grab the straight edges of the inner and outer walls, and then find the angles θ_inside and θ_outside where the two adjacent sides intersect to determine whether they meet the requirements of the preset threshold angle and whether the product is skewed or deformed.

5. The method according to claim 1, characterized in that: The interference features are automatically compatible and include: If the edge grabbing trajectory is a straight line area, the straight line correlation algorithm is used to automatically fit the ideal welding points of burrs, interference features and other points; If the edge grabbing trajectory is an arc area, the arc fitting analytical algorithm is used to automatically fit the ideal welding points of burrs, interference features and other points.

6. A positioning device for welding a lithium battery cover, characterized in that: include: a preprocessing unit, configured to obtain image data to be processed of a cover plate to be welded, the cover plate to be welded comprising a first side to be welded and a second side to be welded; capture a first endpoint and a second endpoint of the first side to be welded from the image data to be processed, and capture a third endpoint and a fourth endpoint of the second side to be welded from the image data to be processed, wherein the first endpoint is adjacent to the third endpoint, and the second endpoint is adjacent to the fourth endpoint; determine the midpoint coordinates of the first endpoint and the third endpoint to obtain a first midpoint coordinate, and determine the midpoint coordinates of the second endpoint and the fourth endpoint to obtain a second midpoint coordinate; The trajectory positioning unit is used to determine the welding start coordinates and the welding end coordinates according to the first midpoint coordinates, the second midpoint coordinates and a preset welding offset.

7. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores at least one program, and the at least one program is loaded and executed by the processor to implement the positioning method for welding a lithium battery cover plate as described in any one of claims 1 to 5.

8. A positioning system for lithium battery cover welding, characterized in that: include: An image acquisition device, a welding device, and a welding positioning device as described in right 6; The image acquisition device is used to acquire the original acquired image of the welding cover plate, and send the image of the cover plate to be welded to the welding cover plate positioning device; The welding positioning device is used to analyze and process the original collected image to obtain the welding start coordinates and the welding end coordinates, and provide the welding start coordinates and the welding end coordinates to the welding device; The welding device is used to weld the cover plate according to the welding start coordinates and the welding end coordinates.

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