Minimizing the optical cell-to-module losses for MWT-modules

Minimizing the optical and electrical losses from cell to module is essential for highly efficient PV modules. We use metal wrap through (MWT) solar cells with passivated rear surface to integrate them into a PV-module and minimize the cell to module losses. For this purpose, we analyze the optical properties of different encapsulation materials with respect to this specific cell type, i.e. the absorption losses in the encapsulants and coupling gains from refractive index. The best performing encapsulant shows a cell-to-module power loss of 0% for a 16-cell MWT module. The fill factor loss is 1.4% absolute. We reach a module efficiency of 17.4% on the aperture area implying a CTM-loss in efficiency of only 0.5% absolute.