Pattern of Partial Rear Contacts for Silicon Solar Cells

Partial rear contacts solar cells, which are passivated and locally contacted on their rear side, are widely used for their higher performances, especially in open-circuit voltage. If the distance in between two contacts has been optimized, the best geometry of a contact lattice remains unclear. So far, the most widely explored geometry is the square lattice. This work aims to explore, by the mean of numerical simulations on both PERL and PERT architectures, the consequences of different lattice geometries, and more specifically triangular and hexagonal patterns. This study was extended to the variation of a set of material and process parameters in order to observe the consequences on conversion efficiency for each contact pattern. Once the simulations performed, it has been demonstrated that even though these three geometries show the same optimal efficiency when varying the distance in between two contacts, the triangular contact pattern is clearly more robust with the variation of this distance, which makes it a good candidate for fully optimized solar cells. Moreover, the variation of material and process parameters shows the interest of the triangular contact pattern in case of degraded parameters.