Measurement of Photovoltaic Cell Crack Characteristics in Modules Using Digital Image Correlation

DuraMAT is using digital image correlation (DIC) to measure photovoltaic (PV) cell crack apertures as a function of mechanical and thermal stress. DIC is a technique that compares sequential images to identify fine-scale displacements and distortions in a sample. 

While much effort has been made to identify the presence and length of PV cell cracks in laminated modules using electroluminescence (EL) and ultraviolet fluorescence (UVF) imaging techniques, little is known about the distribution of crack apertures or gaps and how they change with changing temperature and mechanical stress. The major reason for this lack of understanding is that it is very difficult to accurately measure crack apertures in full-sized modules with existing optical methods (e.g., microscopy, optical profilometry, etc.).