Method for manufacturing a photovoltaic module, photovoltaic module

Abstract

The application relates to the photovoltaic technical field and discloses a preparation method of a photovoltaic module and the photovoltaic module. The preparation method of the photovoltaic module comprises the following steps: obtaining first compensation data of a first cell piece in the process that a manipulator grabs the first cell piece from a first conveying device and places the first cell piece on a second conveying device; the first compensation data represents a position deviation of the first cell piece on the first conveying device; obtaining second compensation data of the first cell piece; the second compensation data represents a position deviation of the first cell piece and the second conveying device in the case that the first cell piece reaches a target range of the second conveying device and is not placed on the second conveying device; obtaining target compensation data according to the first compensation data and the second compensation data, so as to control the manipulator to adjust a position of the first cell piece placed on the second conveying device based on the target compensation data; and thus, the deviation of the cell piece in the negative interval series welding process is reduced, and the yield of the photovoltaic module is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photovoltaic, in particular to a preparation method of photovoltaic module and photovoltaic module. BACKGROUND

[0002] In the preparation process of photovoltaic module, cell string welding plays a decisive role in improving the power and mechanical reliability of photovoltaic module. In order to improve the power of photovoltaic module, the negative interval string welding has become the main development trend of cell string welding at present, and the negative interval string welding is to physically overlap the front main grid area of the next cell with the back electrode area of the previous cell, so as to form a negative cell interval.

[0003] However, the current cell has a large error in the process of negative interval string welding, which leads to a low yield of photovoltaic module and cannot meet the design requirements of photovoltaic module. SUMMARY

[0004] The purpose of the embodiments of the present application is to provide a preparation method of photovoltaic module and photovoltaic module, so as to reduce the deviation of the cell in the process of negative interval string welding and improve the yield of photovoltaic module.

[0005] To solve the above technical problems, the embodiments of the present application provide a preparation method of photovoltaic module, comprising: obtaining first compensation data of a first cell in the process that a manipulator grabs the first cell from a first conveying device and places the first cell on a second conveying device; the first compensation data representing the position deviation of the first cell on the first conveying device; obtaining second compensation data of the first cell; the second compensation data representing the position deviation of the first cell and the second conveying device in the case that the first cell reaches the target range of the second conveying device and is not placed on the second conveying device; obtaining target compensation data according to the first compensation data and the second compensation data, so as to control the manipulator to adjust the position of the first cell placed on the second conveying device based on the target compensation data.

[0006] The embodiments of the present application also provide a photovoltaic module, which is prepared by the preparation method of photovoltaic module as described above.

[0007] In some embodiments, the first compensation data of the first cell piece is obtained by: obtaining first image data of the first cell piece on the first conveying device; the first image data is obtained by a CCD camera using a ring-shaped polarized light source; a first outline image of the first cell piece is extracted in the first image data using a Canny edge detection algorithm; a maximum connected domain is extracted in the first outline image, and a center position data of the first cell piece is determined in the maximum connected domain; the first compensation data is obtained according to a deviation of the center position data from a target center position in the first conveying device; wherein the first compensation data includes a first compensation amount in a first direction, a second compensation amount in a second direction, and a compensation angle; the first direction is the moving direction of the first conveying device, and the second direction is perpendicular to the first direction and parallel to the surface of the first conveying device on which the first cell piece is placed.

[0008] In some embodiments, the second compensation data of the first cell piece is obtained by: when the first cell piece is within a target range of the second conveying device and is not placed on the second conveying device, obtaining first edge feature data of the first cell piece and obtaining second edge feature data of a second cell piece placed on the second conveying device; when the first cell piece is placed on the second conveying device, the first cell piece is adjacent to the second cell piece; an optimal offset amount between the first cell piece and the second cell piece is obtained according to the first edge feature data and the second edge feature data; the second compensation data is obtained according to the first edge feature data, a target position on the second conveying device, and the optimal offset amount.

[0009] In some embodiments, the first edge feature data of the first cell piece is obtained by: obtaining first point cloud data by synchronously scanning the first cell piece by at least one laser sensor; the laser sensor is arranged on the second conveying device; the first edge feature data is obtained by edge extraction on the first point cloud data; the second edge feature data of the second cell piece placed on the second conveying device is obtained by: obtaining second point cloud data by synchronously scanning the second cell piece by at least one laser sensor; the second edge feature data is obtained by edge extraction on the second point cloud data.

[0010] In some embodiments, obtaining the optimal offset between the first battery cell and the second battery cell based on the first edge feature data and the second edge feature data includes: obtaining a first edge curvature of the first battery cell based on the first edge feature data; obtaining a second edge curvature of the second battery cell based on the second edge feature data; and obtaining the optimal offset between the first edge curvature and the second edge curvature using a curvature matching algorithm.

[0011] In some embodiments, obtaining the second compensation data based on the first edge feature data, the target position on the second transmission device, and the optimal offset includes: extracting first position information of any target edge point from the first edge feature data; extracting second position information corresponding to the target edge point from the target position on the second transmission device; and obtaining the second compensation data based on the first position information, the second position information, the optimal offset, and the compensation angle; wherein the second compensation data includes a third compensation amount in a third direction and a fourth compensation amount in a fourth direction; the third direction is the movement direction of the second transmission device, and the fourth direction is perpendicular to the third direction and parallel to the surface on which the second battery cell is placed on the second transmission device.

[0012] In some embodiments, obtaining target compensation data based on the first compensation data and the second compensation data includes: determining a first weight of the first compensation data and a second weight of the second compensation data according to an exponential decay weight; the first weight is directly proportional to the exponential decay weight, and the second weight is inversely proportional to the exponential decay weight; obtaining the target compensation data based on the first compensation data, the second compensation data, the first weight, and the second weight.

[0013] In some embodiments, the method further includes: acquiring third compensation data for the first battery cell; the third compensation data includes at least one of the following compensations: thermal expansion compensation, vibration compensation, and belt slippage compensation; the step of acquiring target compensation data based on the first compensation data and the second compensation data includes: acquiring target compensation data based on the first compensation data, the second compensation data, and the third compensation data.

[0014] In some embodiments, obtaining target compensation data based on the first compensation data, the second compensation data, and the third compensation data includes: obtaining fourth compensation data based on the second compensation data and the third compensation data; determining a third weight of the first compensation data and a fourth weight of the fourth compensation data according to an exponential decay weight; wherein the third weight is directly proportional to the exponential decay weight and the fourth weight is inversely proportional to the exponential decay weight; and obtaining the target compensation data based on the first compensation data, the fourth compensation data, the third weight, and the fourth weight.

[0015] The technical solution provided in this application has at least the following advantages:

[0016] This application acquires first compensation data of the first solar cell on the first transmission device and second compensation data of the first solar cell reaching the target range of the second transmission device but not placed on the second transmission device. Based on the first and second compensation data, target compensation data is obtained. This data is then used to control the robotic arm to adjust the position of the first solar cell on the second transmission device. As the robotic arm picks up the first solar cell from the first transmission device and places it on the second transmission device, the placement position of the robotic arm end is detected in real time and adjusted accordingly. This reduces the deviation of the solar cells during the negative-pitch stringing process, eliminates the influence of the accuracy deviation of the stringing equipment's cell placement system and the cell tolerance on the stringing deviation, and improves the yield of photovoltaic modules. Attached Figure Description

[0017] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0018] Figure 1 This is a schematic diagram of the structure of a laser dynamic polarization correction system according to an embodiment of this application;

[0019] Figure 2 This is a schematic flowchart of a method for manufacturing a photovoltaic module according to an embodiment of this application;

[0020] Figure 3 This is a flowchart illustrating the various sub-steps of step 101 according to an embodiment of this application;

[0021] Figure 4 This is a flowchart illustrating the various sub-steps of step 102 according to an embodiment of this application;

[0022] Figure 5 This is a flowchart illustrating the various sub-steps of step 1022 according to an embodiment of this application;

[0023] Figure 6 This is a flowchart illustrating the various sub-steps of step 1023 according to an embodiment of this application;

[0024] Figure 7 This is a flowchart illustrating the various sub-steps of step 103 according to an embodiment of this application;

[0025] Figure 8 This is another schematic flowchart of a method for preparing a photovoltaic module according to an embodiment of this application. Detailed Implementation

[0026] As can be seen from the background technology, the current process of negative-pitch stringing of solar cells has a large error, which cannot meet the design requirements of photovoltaic modules.

[0027] Analysis revealed that the large error in the current negative-pitch stringing process of solar cells is due to the following: the current photovoltaic module stacking process requires a negative pitch of approximately -0.4mm, with an allowable deviation of ±0.1mm. However, the current stringing equipment's cell placement system has a deviation of ±0.3mm (±0.15mm for CCD positioning, ±0.05mm for the handling robot, and ±0.1mm for belt conveyor), and a cell tolerance of ±0.2mm (including a cell tolerance of ±0.1mm and a dicing accuracy of ±0.1mm). When these two are combined in the same direction, the maximum deviation is ±0.5mm, far exceeding the product design requirement of -0.4mm ±0.1mm. Furthermore, analysis of the defect rate using Monte Carlo simulation data revealed that, under the maximum deviation of ±0.5mm, the probability of the final product having a cell spacing greater than the designed cell spacing of -0.4mm ±0.1mm exceeds 18%. This results in significant errors during the negative-pitch stringing process, posing a risk of light leakage from the visible cells in the photovoltaic module, leading to poor power output and mechanical reliability, and failing to meet the design requirements. The table below shows the error sources and values ​​at each stage of the existing negative-pitch stringing process.

[0028]

[0029] Furthermore, existing stringing systems suffer from static compensation failure during the production of FP (Full Plate) shingled modules, meaning dynamic misalignment cannot be suppressed. Existing systems rely on a regularized CCD (Charge-Coupled Device Camera) for position compensation before wafer placement, but this cannot address dynamic disturbances during the placement process. Vibration of the conveyor belt can cause cell slippage, and thermal stretching of the belt can also increase the cumulative error. The robotic arm has inertia, and overshoot occurs during sudden stops, which can easily cause microcracks in thin-cell scenarios. Currently, stringing systems only support adjustment in the X direction, while the Y direction relies on initial CCD compensation, which can easily lead to misalignment accumulation, reducing the overlap area of ​​the stacked cells and causing light leakage. In addition, the Y-direction of the handling arm is rigidly fixed and cannot respond to belt misalignment (a common deviation angle of 0.5° can cause an end offset of 0.3mm). However, the current system lacks real-time detection after wafer unpacking, and defects are usually discovered after the module is packaged. Furthermore, the response delay of EL (Electroluminescence) detection is relatively long, resulting in the generation of defective products in batches and a low yield of photovoltaic modules.

[0030] To address the aforementioned technical problems, this application provides a method for manufacturing a photovoltaic module, comprising: acquiring first compensation data of the first solar cell during the process of a robotic arm picking up a first solar cell from a first transmission device and placing it on a second transmission device; the first compensation data representing the positional deviation of the first solar cell on the first transmission device; acquiring second compensation data of the first solar cell; the second compensation data representing the positional deviation between the first solar cell and the second transmission device when the first solar cell reaches the target range of the second transmission device but is not placed on the second transmission device; and acquiring target compensation data based on the first compensation data and the second compensation data to control the robotic arm to adjust the position of the first solar cell placed on the second transmission device based on the target compensation data.

[0031] This application acquires first compensation data of the first solar cell on the first transmission device and second compensation data of the first solar cell reaching the target range of the second transmission device but not placed on the second transmission device. Based on the first and second compensation data, target compensation data is obtained. This data is then used to control the robotic arm to adjust the position of the first solar cell on the second transmission device. As the robotic arm picks up the first solar cell from the first transmission device and places it on the second transmission device, the placement position of the robotic arm end is detected in real time and adjusted accordingly. This reduces the deviation of the solar cells during the negative-pitch stringing process, eliminates the influence of the accuracy deviation of the stringing equipment's cell placement system and the cell tolerance on the stringing deviation, and improves the yield of photovoltaic modules.

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the various embodiments of this application will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the various embodiments of this application to help readers better understand this application. However, the technical solutions claimed in this application can be implemented even without these technical details and various changes and modifications based on the following embodiments. The division of the various embodiments below is for the convenience of description and should not constitute any limitation on the specific implementation of this application. The various embodiments can be combined with and referenced by each other without contradiction.

[0033] One embodiment of this application relates to a method for fabricating a photovoltaic module. This method utilizes a laser dynamic polarization correction system, such as... Figure 1 The diagram shows the structure of the laser dynamic correction system in this embodiment, including a first transmission device, a second transmission device, and a robotic arm. The first transmission device is a feeding belt equipped with a CCD camera. The second transmission device is a welding belt equipped with laser sensors. There can be three laser sensors: one located in the belt transmission direction and two located on the upper and lower sides of the belt, respectively. The robotic arm is equipped with a welding fixture and a feeding suction cup. The robotic arm is used to pick up the first battery cell from the first transmission device and place it in the second transmission device using the feeding suction cup. Then, the second transmission device, i.e., the welding belt, fixes multiple battery cells using vacuum adsorption or mechanical clamps to prevent them from moving during the welding process, ensuring that the welding fixture, such as a laser welding head or an arc welding gun, can weld in precise positions to form a battery string.

[0034] In this embodiment, the robotic arm is controlled by a piezoelectric controller in a piezoelectric micro-motion platform. During the process of the robotic arm picking up the first solar cell from the first transmission device and placing it on the second transmission device, the controller acquires first compensation data of the first solar cell on the first transmission device via a CCD camera. It also acquires second compensation data of the first solar cell relative to the second transmission device when the first solar cell reaches the target range of the second transmission device but is not yet placed on it, via a laser sensor. Based on the first and second compensation data, target compensation data is obtained to control the robotic arm to adjust the position of the first solar cell on the second transmission device. This allows for real-time detection and adjustment of the placement position of the robotic arm's end effector during the process of picking up and placing the first solar cell from the first transmission device and placing it on the second transmission device, reducing deviations in the negative-pitch stringing process and improving the yield of photovoltaic modules.

[0035] like Figure 2The diagram shown is a flowchart illustrating the photovoltaic module fabrication method of this embodiment. This method is applied in the process of a robotic arm picking up a first solar cell from a first transfer device and placing it into a second transfer device. The photovoltaic module fabrication method includes the following steps:

[0036] Step 101: Obtain the first compensation data for the first battery cell.

[0037] Specifically, the first compensation data represents the positional deviation of the first battery cell on the first transmission device.

[0038] The execution entity in this embodiment is the piezoelectric controller in the piezoelectric micro-motion platform. The piezoelectric controller is used to control the movement of the piezoelectric micro-motion platform in real time, to achieve high-precision positioning and trajectory tracking, and to process signals from other modules, such as position signals and force sensor signals, to achieve closed-loop control.

[0039] refer to Figure 1 When the first battery cell is located on the first conveyor belt, the piezoelectric controller acquires its position information via a CCD camera. Under normal conditions, the first battery cell coincides with the target center of the first conveyor belt. If there is a deviation, the first battery cell will be offset from the target center on the first conveyor belt, including offset in the X direction (movement direction of the first conveyor belt), offset in the Y direction (perpendicular to and parallel to the movement direction of the first conveyor belt), and offset angle. In this embodiment, the position information of the first battery cell on the first conveyor belt is acquired via a CCD camera to determine the positional deviation of the first battery cell on the first conveyor belt, i.e., the first compensation data.

[0040] In some embodiments, first compensation data is acquired in real time. After acquiring the first compensation data once, the position of the first solar cell on the first transmission device can be adjusted. By acquiring the first compensation data in real time, the positional deviation of the first solar cell on the first transmission device can be eliminated as much as possible. However, this deviation cannot be completely eliminated. Therefore, when the robot arm picks up the first solar cell, the first compensation data of the first solar cell at this time is acquired, thereby providing deviation data for subsequent adjustment of the robot arm's placement of the first solar cell on the second transmission device, improving the accuracy of deviation adjustment, reducing the error of the solar cell in the negative pitch string welding process, and improving the yield of photovoltaic modules.

[0041] Specifically, the CCD camera uses a ring-polarized light source and sub-pixel edge detection to improve the accuracy of the deviation adjustment, i.e., static compensation, of the first transmission device to ±0.05mm. The CCD camera obtains the offset angle based on the principal component analysis rotational deviation calculation method (Python), with an angle resolution of 0.05°.

[0042] likeFigure 3 As shown, it is a schematic flowchart of each sub-step of step 101 of this embodiment. Step 101 is to obtain the first compensation data of the first battery cell, including the following sub-steps:

[0043] Step 1011, obtain the first image data of the first battery cell on the first transfer device.

[0044] Specifically, the first image data is obtained by a CCD camera using a circularly polarized light source. In this embodiment, circularly polarized light is used as active illumination, and the emitted light is polarized light with a single polarization direction. A rotatable analyzer is set in front of the CCD camera, and the analyzer is rotated to be orthogonal to the polarization direction of the circularly polarized light; by a trigger signal, the circularly polarized light is instantaneously lit within 500 µs, and the CCD camera is exposed for 500 µs in the same frame. By exposing once or multiple times and recording the grayscale at different polarization angles, the first image data with anti-reflection can be obtained.

[0045] Step 1012, use the Canny edge detection algorithm to extract the first contour image of the first battery cell from the first image data.

[0046] Specifically, the Canny edge detection algorithm sequentially completes the extraction of the first contour image of the first battery cell through steps such as noise suppression (Gaussian filtering), gradient calculation (amplitude + direction), non-maximum suppression (Non-Maximum Suppression, NMS), double threshold + hysteresis threshold (Hysteresis), etc. Among them, the purpose of noise suppression is to weaken high-frequency noise and prevent misjudging noise as edges; gradient calculation (amplitude + angle) calculates the gradients Gx and Gy in the X and Y directions using a Sobel kernel, the amplitude M(x,y)= , the angle θ(x,y)=arctan(Gy / Gx), and the angle θ(x,y) is quantized into four direction bins of 0°, 45°, 90°, and 135°; non-maximum suppression compares the amplitude M of each pixel with the amplitudes of its two adjacent pixels along the angle θ(x,y) direction. If the amplitude M of this pixel is not the local maximum, this pixel is set to 0 (trimmed); double threshold + hysteresis threshold sets a high threshold Th and a low threshold Tl (for example, Tl = 50, Th = 150). If M corresponding to the pixel ≥ Th, the pixel is a strong edge and this pixel is retained; if M corresponding to the pixel satisfies: Tl ≤ M < Th, the pixel is a weak edge, and it is only retained when the pixel is connected to a strong edge. When the pixel is not connected to a strong edge, it needs to be suppressed. If M corresponding to the pixel < Tl, this pixel needs to be suppressed. The first contour image of the first battery cell extracted by the Canny edge detection algorithm is edges = cv2.Canny(image,Tl = 50,Th = 150), representing all the edges of the image (represented as a pile of lines).

[0047] Step 1013: Extract the largest connected component from the first contour image and determine the center position data of the first battery cell from the largest connected component.

[0048] Specifically, the maximum connected component is extracted from the first contour image. That is, in the above set of lines, all connected white pixels (contours) are found, and then the one with the largest area is selected as the final output. The extracted maximum connected component is contour = find_max_contour(edges).

[0049] In this embodiment, after extracting the largest connected component, the outline of the first battery cell is obtained. Then, the center position data of the first battery cell is determined in the largest connected component, thereby obtaining the deviation between the center position data and the target center position in the first transmission device, and obtaining the first compensation data.

[0050] Step 1014: Obtain first compensation data based on the deviation between the center position data and the target center position in the first transmission device.

[0051] The first compensation data includes a first compensation amount in the first direction (i.e., the X direction), a second compensation amount in the second direction (i.e., the Y direction), and a compensation angle; the first direction is the moving direction of the first transmission device, and the second direction is perpendicular to the first direction and parallel to the surface on which the first battery cell is placed.

[0052] For example, taking a 156mm battery cell as an example, the theoretical target position, i.e., the target center position in the first transmission device, is target_pos=(belt_x0+15.6,belt_y0), where (belt_x0,belt_y0) represent a reference point in the first transmission device. Then, the first compensation amount ΔX0 in the X direction and the second compensation amount ΔY0 in the Y direction are calculated. ΔX0 and ΔY0 are calculated as follows: (ΔX0, ΔY0)=calculate_offset(contour.center,target_pos), where contour.center is the center position data of the largest connected component, including the position data in the X and Y directions. If the center position data contour.center is (100,200) and the target center position target_pos is (150,250), the center position data needs to be moved 50 units to the right in the X direction and 50 units upward in the Y direction to reach the target center position. The compensation angle is Δθ = pca_orientation(contour) - belt_angle, where contour is the largest connected region and belt_angle is the direction of the conveyor belt, i.e. the direction of movement of the first conveyor device. The compensation angle Δθ is calculated by Principal Component Analysis (PCA) to determine the principal direction of the contour in the largest connected region and the angle difference between the principal direction of the contour and the direction of the conveyor belt.

[0053] Specifically, the robotic arm grasps the first battery cell on the first transmission device based on the first compensation data. The position grasped by the robotic arm is robot.move_to(belt_x0+ΔX0, belt_y0+ΔY0, Z=5mm, θ=Δθ), which means that it hovers for 5mm on the Z-axis (the direction perpendicular to the first transmission device).

[0054] Step 102: Obtain the second compensation data for the first battery cell.

[0055] Specifically, the second compensation data represents the positional deviation between the first battery cell and the second transmission device when the first battery cell reaches the target range of the second transmission device but is not placed on the second transmission device.

[0056] refer to Figure 1When the first solar cell is located on the second transmission device, i.e., the welding belt, a laser sensor acquires its position information on the second transmission device. In this embodiment, multiple laser scanners can be set, such as three or four. These multiple laser scanners simultaneously receive trigger signals, ensuring that the information acquired by the multiple laser scanners represents multiple perspectives from the same cross-section in physical space. After the robotic arm grasps the first solar cell, it moves it above the second transmission device, i.e., to the target range of the second transmission device. However, at this point, the first solar cell is not yet placed on the second transmission device. Second compensation data detected by the laser sensor is used to adjust the position of the first solar cell on the second transmission device in real time, thereby reducing welding deviations and improving the yield of photovoltaic modules.

[0057] like Figure 4 The diagram shown is a flowchart of each sub-step of step 102 in this embodiment. Step 102, which involves obtaining the second compensation data of the first battery cell, includes the following sub-steps:

[0058] Step 1021: If the first battery cell reaches the target range of the second transmission device but is not placed on the second transmission device, acquire the first edge feature data of the first battery cell and acquire the second edge feature data of the second battery cell located on the second transmission device.

[0059] When the first battery cell is placed on the second transmission device, the first battery cell is adjacent to the second battery cell.

[0060] Specifically, the first edge feature data of the first battery cell is obtained by the following method: the first battery cell is scanned synchronously by at least one laser sensor to obtain the first point cloud data; the laser sensor is set on the second transmission device; and the first edge feature data is obtained by edge extraction of the first point cloud data.

[0061] Specifically, the second edge feature data of the second battery cell located on the second transmission device is obtained by the following method: the second point cloud data is obtained by synchronously scanning the second battery cell with at least one laser sensor; the second edge feature data is obtained by edge extraction of the second point cloud data.

[0062] This embodiment can set up multiple laser scanners, such as 3 or 4. Multiple laser scanners receive trigger signals at the same time, ensuring that the information acquired by multiple laser scanners is multiple perspectives of the same cross section in physical space. Specifically, the first and second point cloud data can be obtained as follows: Each laser scanner samples at a frequency of, for example, 5 kHz, meaning it can output 5 contour points every 1 ms trigger cycle; then, Savitzky-Golay filtering is performed, mainly to suppress laser speckle and CMOS (Complementary Metal-Oxide-Semiconductor) quantization noise, while retaining sub-pixel level steps. Savitzky-Golay filtering avoids over-smoothing small defects and amplifies high-frequency noise; next, calibration matrix transformation is performed to obtain, for example, a 4×4 homogeneous matrix, uniformly transforming the local coordinates of each laser sensor to world coordinates; finally, multiple aligned contours are stitched together to form a complete cross section, and then nearest neighbor averaging or ICP (Iterative Closest Point) fine-tuning based on KD-Tree (k-dimensional Tree) is performed to eliminate residual extrinsic errors, thus obtaining the first and second point cloud data.

[0063] In this embodiment, after acquiring the first point cloud data and the second point cloud data, edge features are extracted from the first point cloud data to obtain first edge feature data, and edge features are extracted from the second point cloud data to obtain second edge feature data. Both the first and second edge feature data in this embodiment can be upper edge point sets.

[0064] Step 1022: Obtain the optimal offset between the first battery cell and the second battery cell based on the first edge feature data and the second edge feature data.

[0065] like Figure 5 The diagram shown is a flowchart illustrating the various sub-steps of step 1022 in this embodiment. Step 1022 involves obtaining the optimal offset between the first and second battery cells based on the first edge feature data and the second edge feature data, and includes the following sub-steps:

[0066] Step 10221: Obtain the first edge curvature of the first battery cell based on the first edge feature data.

[0067] Step 10222: Obtain the second edge curvature of the second battery cell based on the second edge feature data.

[0068] Step 10223: Use the curvature matching algorithm to obtain the optimal offset between the first edge curvature and the second edge curvature.

[0069] The first edge feature data is set as upper_edge = extract_edge(point_cloud, direction='top'), where upper_edge is a two-dimensional point set representing the contour points of the upper edge of the first battery cell. Then, the edge curvature κ_curr of the first battery cell, i.e., the upper edge curvature, is calculated, for example, κ_curr = compute_curvature(upper_edge). The edge curvature of the first battery cell needs to be acquired in real time. The edge curvature of the second battery cell is also acquired in the same way, but the timing of acquiring the edge curvature of the second battery cell is different. In this embodiment, the second edge feature data of the second battery cell can be acquired in advance when the second battery cell is placed on the second transmission device. The edge curvature of the second battery cell is obtained based on the second edge feature data and stored in advance. When the edge curvature of the first battery cell is acquired later, the edge curvature κ_prev of the second battery cell in the historical record is directly loaded from the file or database, for example, κ_prev = load_prev_battery_curvature().

[0070] Then, the optimal offset Δd=curvature_matching(κ_curr,κ_prev) between the edge curvature of the first battery cell and the edge curvature of the second battery cell is calculated based on the curvature matching algorithm. The curvature matching algorithm usually determines the alignment position of the two battery cells based on the similarity of curvature.

[0071] Step 1023: Obtain second compensation data based on the first edge feature data, the target position on the second transmission device, and the optimal offset.

[0072] The second compensation data includes a third compensation amount in the third direction (X direction of the second transmission device) and a fourth compensation amount in the fourth direction (Y direction of the second transmission device); the third direction is the movement direction of the second transmission device, and the fourth direction is perpendicular to the third direction and parallel to the surface of the second transmission device on which the second battery cell is placed.

[0073] like Figure 6 The diagram shown is a flowchart illustrating the various sub-steps of step 1023 in this embodiment. Step 1023 involves obtaining the second compensation data based on the first edge feature data, the target position on the second transmission device, and the optimal offset. This includes the following sub-steps:

[0074] Step 10231: Extract the first position information of any target edge point from the first edge feature data.

[0075] Step 10232: Extract the second position information corresponding to the target edge point at the target position on the second transmission device.

[0076] Step 10233: Obtain the second compensation data based on the first position information, the second position information, the optimal offset, and the compensation angle.

[0077] In this embodiment, during the process of obtaining the second compensation data based on the first edge feature data, the target position on the second transmission device, and the optimal offset, the first position information (edge_position[0], edge_position[1]) of any target edge point is extracted from the first edge feature data, and the second position information (reference_position[0], reference_position[1]) corresponding to the target edge point is extracted from the target position on the second transmission device. Then, the second compensation data return Vector(ΔX,ΔY) is obtained based on the first position information, the second position information, the optimal offset, and the compensation angle. Among them, the third compensation amount ΔX in the third direction is edge_position[0]-reference_position[0]+Δd×cos(θ), and the fourth compensation amount ΔY in the fourth direction is edge_position[1]-reference_position[1]+Δd×sin(θ), where θ is the offset angle in the first compensation data.

[0078] Step 103: Obtain target compensation data based on the first compensation data and the second compensation data, so as to control the robot arm to adjust the position of the first battery cell placed on the second transmission device based on the target compensation data.

[0079] like Figure 7 The diagram shown is a flowchart illustrating the various sub-steps of step 103 in this embodiment. Step 103 involves obtaining the target compensation data based on the first compensation data and the second compensation data, and includes the following sub-steps:

[0080] Step 1031: Determine the first weight of the first compensation data and the second weight of the second compensation data according to the exponential decay weight.

[0081] Among them, the first weight is directly proportional to the exponentially decaying weight, and the second weight is inversely proportional to the exponentially decaying weight.

[0082] Step 1032: Obtain the target compensation data based on the first compensation data, the second compensation data, the first weight, and the second weight.

[0083] The first compensation data in this embodiment is static compensation, which applies to the entire process of the robot arm handling the first battery cell. When the robot arm grabs the first battery cell on the first transmission device, the robot arm performs static compensation based on the first compensation data. The second compensation data is dynamic compensation, which is activated only at the end of the cell placement (for example, at a height of 5mm from the welding belt). That is, when the first battery cell reaches the target range of the second transmission device but is not placed on the second transmission device, the second compensation data is obtained.

[0084] This embodiment employs a dynamic coordination strategy at the end of the robot's wafer placement process. It spatially fuses the first and second compensation data, obtaining the first weight of the first compensation data and the second weight of the second compensation data. The first and second compensation data are then used to calculate the robot's target compensation data according to their respective weights. The target compensation data are ΔXfinal and ΔYfinal, where ΔXfinal = α × ΔX0 + (1-α) × ΔX and ΔYfinal = α × ΔY0 + (1-α) × ΔY, where α is the first weight, 1-α is the second weight, and α = e (-t / τ) τ is the exponentially decaying weight, for example, τ=0.1s.

[0085] In some embodiments, when the deviation between the first compensation data and the second compensation data is greater than a preset threshold, it indicates that the difference in compensation deviation obtained by the robot arm is large, and an emergency hovering is triggered for manual review; for example, when the difference between ΔX0 in the first compensation data and ΔX in the second compensation data satisfies |ΔX-ΔX0|>0.2mm, an emergency hovering is triggered for manual review.

[0086] This embodiment reduces deviations during negative-pitch stringing of solar cells and improves the yield of photovoltaic modules by real-time detection and adjustment of the robot's end-effector position until the robot places the first solar cell onto the second transfer device. After placing the first solar cell onto the second transfer device, the robot continues to pick up the next solar cell from the first transfer device, repeating the above steps.

[0087] like Figure 8 The diagram shown is another flowchart illustrating the photovoltaic module fabrication method of this embodiment. The photovoltaic module fabrication method of this embodiment includes the following steps:

[0088] Step 201: Obtain the first compensation data of the first battery cell.

[0089] Step 202: Obtain the second compensation data for the first battery cell.

[0090] Step 203: Obtain the third compensation data of the first battery cell.

[0091] This embodiment also obtains third compensation data, which includes at least one of the following compensations: thermal expansion compensation, vibration compensation, and belt slippage compensation.

[0092] Specifically, thermal expansion compensation Δ_thermal = (16.5e-6) × L0 × (Tsensor-T0), where 16.5e-6 is the coefficient of thermal expansion of the material, representing the relative elongation of the belt material per degree Celsius of temperature change, L0 is the initial length of the belt, Tsensor is the temperature measured by the current sensor, and T0 is the reference temperature, which is generally the temperature at which the belt is calibrated or initially operated.

[0093] Vibration compensation is calculated using jerk, which is measured by a MEMS (Micro-Electro-Mechanical Systems) accelerometer. The vibration compensation is calculated as Δ_vibration = 0.003 × jerk, where 0.003 is the vibration compensation coefficient and jerk is the jerk, representing the rate of change of acceleration.

[0094] Belt slippage compensation is calculated based on the speed difference fed back by the encoder. The belt slippage compensation is Δ_belt, where Δ_belt = 0.015 × (v encoder -v setpoint ), 0.015 is the belt slippage compensation coefficient, v encoder v is the actual speed measured by the encoder. setpoint The target speed is set.

[0095] Finally, the obtained third compensation data is Δcomp = Δ_thermal + Δ_vibration + Δ_belt.

[0096] Step 204: Obtain target compensation data based on the first compensation data, the second compensation data, and the third compensation data, so as to control the robot arm to adjust the position of the first battery cell placed on the second transmission device based on the target compensation data.

[0097] Steps 201 and 202 are largely the same as steps 101 and 102 above, and will not be repeated here to avoid repetition.

[0098] This embodiment employs a dynamic coordination strategy at the end of the robot's placement process. It spatially fuses the first, second, and third compensation data to obtain the first weight of the first compensation data. The second and third compensation data are added together to form a single compensation data, and the second weight of this sum is obtained. The target compensation data ΔXfinal and ΔYfinal of the robot are then calculated according to their respective weights. The calculation methods for ΔXfinal and ΔYfinal are: ΔXfinal = α × ΔX0 + (1 - α) × (ΔX + Δcomp), ΔYfinal = α × ΔY0 + (1 - α) × (ΔY + Δcomp), where α is the first weight, 1 - α is the second weight, and α = e (-t / τ) τ is the exponentially decaying weight, for example, τ=0.1s.

[0099] The table below shows the technical parameters of the core modules in the laser dynamic correction system in this embodiment, including: laser sensor, piezoelectric micro-motion platform, piezoelectric controller, temperature sensor, and vibration sensor.

[0100]

[0101] This embodiment employs laser dynamic positioning technology and a common-path laser triangulation method at the end of the robotic arm placement to eliminate vibration interference, achieving a resolution of ±0.01mm, which is 10 times that of traditional visual inspection. This embodiment also provides collaborative compensation for multiple sources of errors during wafer placement, including equipment baseline, cutting tolerance, thermal deformation, vibration, material creep, conveyor belt fluctuations, and residual installation stress, thus eliminating the impact of various errors on placement accuracy. Furthermore, this embodiment achieves millimeter-level real-time position correction at the end of the wafer placement process (e.g., at a height of 0.5mm from the welding belt) through dynamic closed-loop correction, overcoming the limitations of existing open-loop control. Real-time response is achieved through a piezoelectric micro-motion platform, with a closed-loop control bandwidth of >500Hz based on the inverse piezoelectric effect, exceeding that of mechanical actuators by 20 times. Additionally, this embodiment provides the handling arm with fine-tuning capabilities in the Y direction through the piezoelectric micro-motion platform, overcoming existing equipment hardware limitations. Finally, this embodiment also fuses multi-sensor data, integrating laser contour data and belt encoder signals to compensate for transmission vibration, thereby reducing deviations in the negative-pitch string welding process of solar cells and improving the yield of photovoltaic modules.

[0102] The table below shows a comparison of the errors of this embodiment and existing solutions with multiple error sources.

[0103]

[0104] As can be seen, compared with the existing solution, this embodiment reduces the errors of multiple error sources, thereby reducing the overall comprehensive error. The comprehensive error is reduced from the original ±0.5mm to ±0.038mm, which meets the product design requirements of -0.4mm ±0.1mm for the stacking spacing, and improves the yield of photovoltaic modules.

[0105] The table below shows a comparison of the technical effects of this embodiment with existing solutions.

[0106]

[0107] As can be seen, compared with the existing CCD wafer loading system technology, this embodiment reduces the wafer spacing accuracy from ±0.28mm to approximately ±0.038mm, reduces the wafer light leakage defect rate from 62.5% to approximately 0%, and reduces the temperature slip effect from 0.2mm / 10℃ to 0.015mm / 10℃. In addition, the equipment cycle delay of this embodiment is less than 10ms, which can be ignored.

[0108] One embodiment of this application also relates to a photovoltaic module, which is prepared by the photovoltaic module preparation method described above.

[0109] The photovoltaic module of this embodiment is prepared by the above-described photovoltaic module preparation method, thereby reducing the deviation of the cells during the negative pitch stringing process and improving the yield of the photovoltaic module.

[0110] Those skilled in the art will understand that the above embodiments are specific embodiments for implementing this application, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of this application.

Claims

1. A method for preparing a photovoltaic module, characterized in that, include: During the process of the robotic arm picking up the first battery cell from the first transmission device and placing it into the second transmission device, the first compensation data of the first battery cell is acquired. The first compensation data represents the positional deviation of the first battery cell on the first transmission device; Acquire second compensation data for the first battery cell; the second compensation data represents the positional deviation between the first battery cell and the second transmission device when the first battery cell reaches the target range of the second transmission device but is not placed on the second transmission device. Target compensation data is obtained based on the first compensation data and the second compensation data, so as to control the robot arm to adjust the position of the first battery cell placed on the second transmission device based on the target compensation data; The step of obtaining the first compensation data for the first battery cell includes: Acquire first image data of the first battery cell on the first transmission device; Extract the first contour image of the first battery cell from the first image data; Extract the largest connected component from the first contour image, and determine the center position data of the first battery cell from the largest connected component; The first compensation data is obtained based on the deviation between the center position data and the target center position in the first transmission device; wherein, the first compensation data includes a first compensation amount in a first direction, a second compensation amount in a second direction, and a compensation angle; the first direction is the moving direction of the first transmission device, and the second direction is perpendicular to the first direction and parallel to the surface of the first transmission device on which the first battery cell is placed.

2. The method for preparing a photovoltaic module according to claim 1, characterized in that, The first image data was acquired by a CCD camera using a ring-polarized light source; Extracting the first contour image of the first battery cell from the first image data includes: The first contour image of the first battery cell is extracted from the first image data using the Canny edge detection algorithm.

3. The method for preparing a photovoltaic module according to claim 2, characterized in that, The step of obtaining the second compensation data for the first battery cell includes: When the first battery cell reaches the target range of the second transmission device but is not placed on the second transmission device, the first edge feature data of the first battery cell is acquired, and the second edge feature data of the second battery cell located on the second transmission device is acquired; when the first battery cell is placed on the second transmission device, the first battery cell and the second battery cell are adjacent. The optimal offset between the first battery cell and the second battery cell is obtained based on the first edge feature data and the second edge feature data. The second compensation data is obtained based on the first edge feature data, the target position on the second transmission device, and the optimal offset.

4. The method for preparing a photovoltaic module according to claim 3, characterized in that, The step of obtaining the first edge feature data of the first battery cell includes: First point cloud data is obtained by synchronously scanning the first battery cell using at least one laser sensor; the laser sensor is mounted on the second transmission device. The first edge feature data is obtained by edge extraction of the first point cloud data; The acquisition of the second edge feature data of the second battery cell located on the second transmission device includes: Second point cloud data is obtained by synchronously scanning the second battery cell using at least one of the laser sensors; The second edge feature data is obtained by performing edge extraction on the second point cloud data.

5. The method for preparing a photovoltaic module according to claim 3, characterized in that, The step of obtaining the optimal offset between the first battery cell and the second battery cell based on the first edge feature data and the second edge feature data includes: The first edge curvature of the first battery cell is obtained based on the first edge feature data; The second edge curvature of the second battery cell is obtained based on the second edge feature data; The optimal offset between the first edge curvature and the second edge curvature is obtained by using a curvature matching algorithm.

6. The method for preparing a photovoltaic module according to claim 3, characterized in that, The step of obtaining the second compensation data based on the first edge feature data, the target position on the second transmission device, and the optimal offset includes: Extract the first location information of any target edge point from the first edge feature data; Extract the second location information corresponding to the target edge point at the target location on the second transmission device; The second compensation data is obtained based on the first position information, the second position information, the optimal offset, and the compensation angle; wherein, the second compensation data includes a third compensation amount in a third direction and a fourth compensation amount in a fourth direction; the third direction is the moving direction of the second transmission device, and the fourth direction is perpendicular to the third direction and parallel to the surface of the second transmission device on which the second battery cell is placed.

7. The method for preparing a photovoltaic module according to claim 1, characterized in that, The step of obtaining the target compensation data based on the first compensation data and the second compensation data includes: The first weight of the first compensation data and the second weight of the second compensation data are determined according to the exponential decay weight; the first weight is directly proportional to the exponential decay weight, and the second weight is inversely proportional to the exponential decay weight. The target compensation data is obtained based on the first compensation data, the second compensation data, the first weight, and the second weight.

8. The method for preparing a photovoltaic module according to claim 1, characterized in that, The method further includes: Obtain the third compensation data of the first battery cell; the third compensation data includes at least one of the following compensations: thermal expansion compensation, vibration compensation, and belt slippage compensation; The step of obtaining the target compensation data based on the first compensation data and the second compensation data includes: Target compensation data is obtained based on the first compensation data, the second compensation data, and the third compensation data.

9. The method for preparing a photovoltaic module according to claim 8, characterized in that, The step of obtaining target compensation data based on the first compensation data, the second compensation data, and the third compensation data includes: The fourth compensation data is obtained based on the second compensation data and the third compensation data; The third weight of the first compensation data and the fourth weight of the fourth compensation data are determined according to the exponential decay weight; the third weight is directly proportional to the exponential decay weight, and the fourth weight is inversely proportional to the exponential decay weight. The target compensation data is obtained based on the first compensation data, the fourth compensation data, the third weight, and the fourth weight.

10. A photovoltaic module, characterized in that, The photovoltaic module is prepared by the photovoltaic module preparation method as described in any one of claims 1 to 9.

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