Thermal Characterization of Junction in Solar Cell Packages

This is the first report on the direct measurement of the junction temperature and on the determination of thermal resistance of a commercial amorphous silicon (a-Si) solar cell package under real operating conditions. Thermal transient method was utilized for the thermal characterization. Irradiation of sunlight to the solar cell package was found to induce significant heat generation inside the solar cell package. It was shown that the driving of the solar cell package with a sun power of 1 sun (100 mW/cm² and 1.5 AM) resulted in a junction temperature of about 113°C. Surprisingly, the temperature difference between the junction and the case surface of the solar cell package was as high as 43°C. The efficiency drop was observed with the increase of junction temperature in the solar cell package. Thermal resistance was determined under various operating conditions.