Effects of lateral resistances in photovoltaic cells and full 2-D parameter extraction for the spatially-resolved models using electroluminescence images

This paper investigates the influences of the lateral resistances in photovoltaic (PV) devices, and proposes a method for extracting local electrical parameters of thin-film PV devices based on a 2-D spatially-resolved model utilising electroluminescence (EL) images and 2-D fittings. PV-oriented nodal analysis (PVONA) is used for studying the electrical properties of the devices and for simulations in iterative 2-D fitting processes. It is shown that the effects of the lateral resistances should not be simply replaced by lumped effective resistances. The proposed new method employs firstly the dark-I-V fitting for the junction parameters; and secondly 2-D fitting of EL images taken under varying bias levels, for the internal and lateral series resistances. The method is verified by a case study and demonstrates excellent agreements with measurement data.