Assessment of Solar Cell Parameters Extraction Methods through Temperature Dependent Current-Voltage Measurements

The cell parameters corresponding to the classical DC single diode model with series and shunt resistances are extracted thanks to current versus voltage characteristics analysis. We have implemented with Matlab two different methods recently proposed in the literature. The first method, which is exact, is based on the use of the Lambert function to solve analytically the non-explicit equation describing the electrical equivalent circuit . The second method, which is an approximate one, consists in separating the I-V characteristics into two parts, a linear and an exponential one to derive the parameters which are the most significant for each zone. A third method has also been used with a variational least squares minimisation over all data points. We have applied these extraction methods to I (V, T) measurements performed at different temperatures and we have analyzed the temperature evolution of the 4 extracted parameters of a crystalline silicon solar cell under dark conditions (series and parallel resistance, saturation current density and ideality factor of the diode). This gives us insight on the electronic transport in the solar cell. We discuss the validity range of a single diode model and we establish the complementarity of these methods over a range of temperatures.