HELENE – High-efficiency and low-cost PERx solar cells as precursors for an economic feasible realization of storage-supported PV systems

Using industry-relevant process technologies, HELENE aims to increase the efficiency of industrially fabricated silicon solar cells to 22.5%. To this end, PERC (Passivated Emitter and Rear Cell) solar cells will be developed to replace the established Al-BSF (Aluminum Back Surface Field) technology. The aims of ISFH’s subproject are:

• Further development of simulation models and characterization methods to analyze the impact of recombination on the fill factor and the open-circuit voltage of PERC solar cells.
• Investigation of the impact of BO, Fe, and Cu on the minority-carrier lifetime and long-term stability of the efficiency of PERC solar cells.
• Development of Ag front grids that are compatible with the MultiWire interconnection technique.
• Thorough characterization of the formation of local aluminum contacts and development of a fundamental model thereof. Optimization of laser contact openings and Al screen-printing for PERC and PERC+ solar cells.
• Optimization of a wet chemistry polishing process to smooth the rear side of PERC solar cells and subsequent cleaning steps.

At the end of the project, the research and development results of all HELENE partners will be combined at the site of the project coordinator SolarWorld Innovations to enable the fabrication of a 22.5% PERC solar cell.