A generalized electric model for mono and polycrystalline silicon in the presence of cracks and random defects

Damage, micro-cracks, grain boundaries and other defects in solar cells are impacting on the electric power-loss of photovoltaic modules, their actual solar conversion efficiency and also their lifetime. In the present contribution, a one-dimensional model for simulating the electric current distribution in solar cells accounting for a distributed series resistance is generalized to the presence of partially conductive cracks. The proposed model is used to perform a quantitative analysis of electroluminescence (EL) images of cracked monocrystalline silicon solar cells. A further generalization in a stochastic direction is also proposed in order to take into account randomly distributed defects typical of polycrystalline silicon.