Study of the Localized Heating of Si Solar Cells by Thermal Imaging and Scanning Electron Microscopy

The aim of this study was to investigate the localized solar cells heating by thermal imaging, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The electrical measurements and thermal infrared measurements were done on the commercial crystalline Si cells (10 cm x 10 cm). SEM was used for the observation of the localized heating. The I-V characteristics of all cells were quite similar with a small spread in the electrical parameters, while the IR images were different: some cells had quite uniform temperature profiles distribution and other ones showed the localized heating. The energy dispersive spectroscopy (EDS) analysis showed that some hot spots have high metal impurity contamination. The microstructure investigation of hot spots revealed the micro-cracks presence. Our study found direct correlation between areas of high impurity contamination, micro cracks and hot-spot heating.