Lab 360 Solar Pty Ltd (Lab360) develops commercial daytime photoluminescence (DPL) systems and services.
Luminescence imaging has become a global standard for the characterisation and inspection of silicon ingots, wafers, solar cells and modules, used routinely in R&D and in high volume manufacturing of solar cells and modules. Photoluminescence (PL) imaging was first proposed and demonstrated for silicon wafers and solar cells by our team at the University of New South Wales, Australia (UNSW). At Lab360 we develop DPL imaging solutions for field inspection of solar modules in full daylight, using the sun itself as the excitation source.
High quality DPL image acquisition is enabled by switching the operating point of modules optically. The single module optical switching technique enables DPL image acquisition on individual modules. The string switching technique can be used in utility scale solar farms, enabling DPL image acquisition of entire strings or of individual modules.
DPL image of a string of modules acquired using optical switching, showing DPL intensity variations between cells (indicative of degradation) and the presence of one module containing an open circuited sub string (yellow arrow). Red arrow indicate gaps between modules.
DPL image acquisition using optical string switching at an Australia solar farm, the camera mounted on a mobile tripod.
DPL image of a module showing the presence of several cell cracks. The image also contains several examples of the so-called Yin Yang defect.
Distortion corrected DPL image (left) in comparison with an EL image measured under controlled laboratory conditions. Both images were converted into voltage loss images (scale is in mV).
High quality DPL image acquisition is enabled by switching the operating point of modules via the system inverter. DPL images can be acquired on individual modules, on groups of modules or on all modules connected to the same inverter. Image acquisition can be from a ground-based tripod, telescopic pole or from aerial drones. In utility scale solar farms this allows the acquisition of DPL images containing several hundreds to thousands of modules in a single image.
DPL image acquired on a residential rooftop system, using inverter switching, showing half of one module, exhibiting a several centimetre long microcrack.
DPL image acquired on a residential rooftop system, using inverter switching, showing half of one module, exhibiting several examples of the so-called Yin Yang defect.
DPL image acquired on a residential rooftop system, using inverter switching, with image acquisition from a telescopic pole.
Aerial drone-based DPL image acquisition at an Australian solar farm
DPL image acquired in an Australian solar farm using inverter switching, showing substantial quality variations between modules
Left: High level DPL image acquired from an aerial drone in an Australian solar farm using inverter switching. Right: Close up DPL image of modules highlighted in the high-level image.
A unique solution for DPL image acquisition is based on the use of a so-called ultranarrow bandpass filter. It enables DPL image acquisition with a single shot, akin to taking photographs with a conventional point and shoot camera.
DPL image acquired using the single image technique of a module following a severe hailstorm, exhibiting several cell cracks
DPL image acquired using the single image technique of a section of a solar farm exhibiting significant DPL intensity contrast between modules, indicative of severe module quality variations, resulting from degradation.