Influence of the temperature on the intrinsic parameters of thin-film modules

The electrical parameters, the ideality diode factor and the parasitic resistances of a photovoltaic module can be estimated from its current-voltage (I-V) curve. However, there are only very few studies focused on thin-film devices, that could have a thermal behavior different from crystalline silicon technologies. This study analyzes the variation of these parameters from a set of current-voltage curves of several commercial modules from different technologies: single-crystalline silicon (sc-Si), multi-crystalline silicon (mc-Si), amorphous silicon (a-Si), tandem of micro-crystalline silicon and amorphous silicon (a-Si/mu c-Si), tandem of cadmium selenide and cadmium telluride (CdS/CdTe), and copper indium selenide (CIS). Most of the modules present a positive value for the current thermal coefficient (a), but the voltage and power temperature coefficients (/I and y ) are negative in all the cases. With respect the series resistance (RS), it is significantly higher for the thin-film modules than for the crystalline silicon ones. Moreover, the thermal coefficient of the series resistance (x) varies depending on the technology. Regarding the shunt resistance (RSh), it seems to be insensitive with respect the temperature fora small range. Finally, the diode ideality factor (m) seems to be constant for crystalline silicon whereas it depends on the temperature for thin-film.