We present the integrated development of back-contacted solar cells and an adequate module interconnection for a high-efficiency photovoltaic module. We report on a large area (125 × 125) mm2 back-junction back-contact n-type solar cell metallized with aluminum having a total area conversion efficiency of 20.7%. To transfer the high conversion efficiency to the module, we use the laser welding process named aluminum-based mechanical and electrical laser interconnection for module integration of these back-contacted solar cells. We further analyze the impact of the busbars of our back-junction back-contact cells on the cell performance and report on optimization of the cell/module interface. The new cells have an adapted rear-side geometry by omitting the emitter busbar. A proof-of-concept module consisting of these cells is presented. Copyright © 2012 John Wiley & Sons, Ltd.