Design, construction and testing of an I-V tester for thin-film solar cells and mini-modules

Abstract

In this project, a cost-effective but highly versatile and powerful current-voltage (I-V) tester for thin-film solar cells and modules was designed, constructed, and thoroughly tested. The I-V tester is able to measure thin-film modules with a size of up to 30 cm x 40 cm. The I-V tester uses steady-state illumination from a high-powered xenon lamp and is able to measure I-V curves at light intensities in the 0.001 to 1.2 suns range. The tester is also able to measure short-circuit current density vs. open-circuit voltage (Jsc-Voc) curves and dark I-V curves. Using water cooling technology, the solar cell or module temperature is kept constant at a user-defined value in the range of 20-60 ?C. The measured curves are analyzed by a computer program built into the tester, yielding important device parameters such as the solar cell/module photovoltaic efficiency, fill factor, series and shunt resistances, and the voltage dependent diode ideality factor.