Validation of analytic modelling of local rear contacts in PERC/PERL solar cells
This work focuses on the comparison of analytical modelling of local rear contacts with two- and three-dimensional (2D and 3D) numerical simulation. The analytical models were developed to calculate the effective surface recombination velocity (Seff) of the rear surface and the bulk contribution to the series resistance (RS_rear). These parameters represent an effective rear surface and when combined to a one-dimensional (1D) simulation can be used to model the current-voltage characteristics of the solar cell. The first achievement of this paper is a solid comparison of the analytical model and the numerical simulation. The deviation is found to be lower than 20% for more than 95% of the data reported. However the model of Seff is found to be limited to open circuit (OC) condition. Therefore a correction, which extended the validity range of the Seff calculation to maximum power point (MPP) condition, is proposed without loss of accuracy. The last achievement is the comparison of the efficiencies obtained using the 1D simulation with the ones obtained using the 2D and 3D numerical simulation. This method ensures with 95% confidence that the deviation in efficiency will not exceed ± 0.18%abs for point contact and ± 0.28%abs for line contacts.