Back-Contacted High-Efficiency Silicon Solar Cells - Opportunities For Low-Cost Metallization And Cell Interconnection

This paper presents ISFH's recent developments and advances in the field of back-contacted silicon solar cells. The efficiency potential of back-contacted solar cells is very high, nevertheless, in industrial production, back-contacted solar cells are decidedly the minority. In the field of back-contacted solar cells, ISFH has developed several cell concepts and new processing techniques, such as laser ablation for silicon structuring, contact opening through passivation layers, and hole drilling for emitter-wrap-through (EWT) solar cells. The latest results are presented regarding ISFH's work on back-junction back-contacted solar cells and EWT solar cells, as well as on back-contacted solar cells employing an amorphous/crystalline silicon heterojunction. Also discussed are the advances in high-throughput evaporation of aluminium as a low-cost option for the metellization of back-contacted solar cells. Finally, a novel, silver-free cell interconnection technique is presented, which is based on the direct laser welding of a highly conductive, low-cost AI foil, as a cell interconnect, onto the rear side of back-contracted solar cells.