Proposing an electro-thermal SPICE model to investigate the effect of partial shading on CIGS PV modules

Abstract

Copper indium gallium (di)selenide (CIGS) photovoltaic (PV) modules are promising for building integrated PV (BIPV) applications because of their low weight to power production ratio. However, previous research shows that (partial) shading of a monolithically interconnected CIGS PV module can cause permanent damage to the shaded region of the module, even when the shading exposure time is very limited. [1, 2] This should be avoided in order to guarantee a 20 year life-span of the BIPV module. In this proceeding, we are investigating the impact of partial shading on CIGS PV modules. For this purpose, we are developing an electro-thermal SPICE model which maps the current density, voltage and temperature distribution of the CIGS PV module in case of shading. First simulations show a significant reverse bias over the partially shaded cell. Also interesting is the fact that the peak current density located in the non-shaded region of the partially shaded solar cell can be visualized. The model allows us to predict when a CIGS PV module may be permanently damaged in shading conditions and whether bypass diodes should be included or not.