Machine-vision technology is currently being employed in several stages of photovoltaic production to supervise and management producing processes. “In edge isolation systems, wafer classification, and solar module inspection, machine vision is being employed to each check the standard of individual method steps and supply feedback to raised perceive and management producing processes themselves,” φωτοβολταικα συστηματα head of the Intralogistics and Image Processing Division at Eckelmann a developer of management systems for industrial automation.

Integrated machine-vision systems are needed for the positioning and measurement of geometric properties like edge and chamfer lengths of solar wafers. These φωτοβολταικα should additionally establish material faults like microcracks or chips and guide laser-based systems to produce laser edge isolation.

Edge isolation provides electrical separation between the active front facet of a solar cell and therefore the rear facet,” says Stelter. “In the sting isolation method, a laser cuts atiny low groove along the cell edges, the depth of the groove looking on the width of the doped emitter layer of the cell. the issue lies in positioning the groove as shut as doable to the outer contour of the cell to maximise the active surface and so the potency of the solar cell.” etching system (see figure). Edge harm is detected and, if the harm is inside tolerance levels, the system proceeds with the cutting method.

As the solar panel is moved across the camera’s field of read, pictures are digitized into a computer using an X64 Xcelera-CL, additionally from DALSA, and edge detection image analysis is performed. because the laser engraves the sting isolation grid into the solar cell, grid distances are measured by the camera and any variations during this price and therefore the expected price are used to make amends for nonlinear errors that will occur.

Image acquisition and analysis occur in 800 ms,” says Stelter. The resolution of the system makes it doable to make sure that laser edge isolation are often performed but a hundred µm from the sting of the wafer. Because the laser and camera system are automatically calibrated by the machine-vision system, recalibration are often automatically performed once any maintenance work. The system calculates a compensation map that’s used for error correction within the management system of the laser deflection unit. Errors within the transport system of the machine are often even be diagnosed using the image-processing system, so granting remedial action to be taken.