From Wafer to Module: Cost-Effective High-Efficiency Silicon Technologies

In the WaMTec project, an ingot/wafer and a module manufacturer, as well as equipment manufacturers and research institutes are joining forces to reduce the manufacturing costs of solar cells with Tunnel Oxide Passivating Contact (TOPCon). The goal is to increase the technology maturity of TOPCon Rear Emitter (TOPCoRE) technology in order to exploit the cost reduction potential of lower cost materials such as p-type wafers and a Cu-based metallization. Processes for the production of low-cost Ga-doped Czochralski (Cz)-Si ingots and wafers are to be developed, which exhibit high charge carrier lifetimes of 10 ms. TOPCoRE cells, which feature plated Cu contacts, will be manufactured from these wafers. A key process for the TOPCoRE cell is the one-sided removal of the backside TOPCon emitter, for which a cost-effective climate-friendly dry etching process will be used. Industrial TOPCoRE solar cells with peak efficiencies of 25.5% will be manufactured and integrated into modules with high-transparency materials and advanced bifacial structuring. They will be subjected to outdoor testing in Turkey and Germany. The developments are accompanied by techno-economic evaluations and life cycle assessments. A major goal is to reduce the cell manufacturing costs (including the wafer) by 10% compared to state-of-the-art TOPCon cells, leading to ~4% lower levelized costs of electricity (LCOE). The aim of the exploitation is the technology transfer to European production sites.