Portable EL Detector: Working Principle, Operation Process and Application in Photovoltaic Cell Detection

The Portable EL Detector is a professional device that provides detailed inspection reports for photovoltaic cells, helping industry practitioners accurately grasp the condition of the cells.

Its working principle is based on the electroluminescence effect of semiconductor materials. When a forward bias voltage is applied to a photovoltaic cell, electrons and holes inside the cell will recombine, and photons will be released during this process. If there are defects in the photovoltaic cell such as hidden cracks, broken grids, or impurities, the carrier recombination efficiency in these defective areas will decrease, presenting dark areas or abnormally bright spots in the infrared imaging of electroluminescence. Normal areas and defective areas will show different luminescent characteristics under electroluminescence, which can be captured by the detection equipment.

When using an EL camera detector to inspect photovoltaic cells, first, the detector must be correctly connected to the photovoltaic cell to ensure that an appropriate forward bias voltage can be applied. After that, the high-resolution camera inside the detector starts working, and it will accurately capture the weak light emitted by the photovoltaic cell during the electroluminescence process. These light rays contain information about the inside of the cell, and the differences in luminous intensity and characteristics in different areas reflect whether there are defects in the cell as well as the type and location of the defects.

After capturing the light signal, the camera converts it into image information and transmits it to the detector's software system. The software analyzes the image through a series of image processing algorithms. It can identify areas in the image that show dark areas or abnormally bright spots, which are the possible defect areas. For example, hidden cracks may appear as irregular dark lines, and broken grids may appear as slender dark strips. The software can not only identify defects but also classify and quantitatively evaluate them. For instance, it can determine the length of hidden cracks, the number of broken grids, etc., and generate a detailed inspection report based on these data.

For photovoltaic cell manufacturers, using EL camera detectors on the production line can conduct quality inspections on each photovoltaic cell before leaving the factory, timely detect and eliminate products with serious defects, and ensure product quality. After the completion of power station construction, by inspecting the photovoltaic cell modules, potential cell damages caused during transportation and installation, such as hidden cracks, can be found in time. In the operation and maintenance of power stations, regular inspection of photovoltaic cells with the Portable EL Detector can timely detect the performance degradation and potential defects of the cells, so that maintenance measures can be taken in advance to ensure the stable power generation efficiency of the power station and reduce economic losses caused by cell failures.