Detecting Photovoltaic Defects with Precision: Tianyi's EL Detector

After long-term use, photovoltaic modules are prone to various defects. Issues such as microcracks and degradation can seriously affect power generation efficiency and the lifespan of the system. This is where the EL detector, a photovoltaic operation and maintenance device, comes into play. It is a common tool in the industry for detecting module defects and has an obvious effect.

The working principle of the EL detector is based on the electroluminescence effect of semiconductors. When a photovoltaic module is supplied with current under a forward bias voltage, electrons and holes in the semiconductor material recombine, releasing energy in the form of photons and generating invisible near-infrared light to the naked eye. The tester's high-sensitivity camera and infrared lens can accurately capture this light signal, and then through the image processing system, convert the internal electrical performance of the module into a grayscale image for display. Relying on this principle, it can identify various module defects.

Microcracks are a common defect in photovoltaic modules, mostly caused by mechanical stress during production, transportation collisions, or improper installation. These tiny cracks are hard to find with the naked eye but can lead to uneven current distribution, significantly reducing power generation efficiency. With the EL detector, the tiny cracks on the cell can be clearly displayed, facilitating timely handling by staff to prevent the problem from worsening.

Another common defect is cell fragmentation. It can cause local short circuits of the cells and affect the overall performance of the module. In the images generated by the EL tester, fragments appear as irregular dark blocks, allowing a direct view of the location and extent of the fragments, helping maintenance personnel quickly find and solve the problem.

The EL tester can also detect the problem of cell grid breakage. Grid breakage will increase the internal resistance of the cell and reduce the output power, which is manifested as missing grid lines or discontinuous dark lines in the EL image. In addition, poor sintering of the cell, that is, the increased contact resistance between the cell electrode and the silicon wafer, will show an abnormally dark area in the corresponding area of the EL image, which can be clearly displayed by the tester. It can also accurately inspect internal welding defects of the module, such as false welding and desoldering of the cell interconnectors, avoiding power loss due to connection problems.

Now, Tianyi has launched an EL detector for the photovoltaic market. This detector is equipped with a 24-megapixel high-sensitivity infrared camera, enabling clearer image analysis; the full-time dark light auto-focus module ensures good focusing effect during night tests; it supports networked wireless control of device detection and viewing and downloading of detection data; the program-controlled constant current power supply can realize 24-hour uninterrupted on-site testing; the tablet computer can be used to wirelessly control device operations and view detection results; the large-capacity energy storage power supply allows on-site detection without complicated preparations; the equipped 3-meter carbon fiber tripod, after installation, facilitates multi-angle testing of modules; the whole machine supports wireless remote operation testing, allowing one person to complete the entire project, and it uses a three-proof drawbar box for convenient and safe carrying and transportation.