Most photovoltaic panels around us integrate crystalline Si solar cells, and this technology will continue to dominate the PV market for the foreseeable future. Increasing performance and production volumes are the main drivers of continued cost reduction in PV, and are indispensable for their broad deployment. Steady progress in crystalline silicon cell efficiencies pushed record values above 25%, however their performance is compromised upon their integration into module. Current module technology is based on stringing of cells for electrical interconnection, and their subsequent lamination for encapsulation between a glass plate and a backsheet. Untapped potential of advanced materials and novel low-stress interconnection technologies in module fabrication is key to continued performance improvement in PV panels. With these goals imec investigates a novel multi-wire approach for cell interconnection. Our approach replaces the three to five metal tabs by thin distributed network of metal wires in a woven fabric based on an imec patented technology. This technology not only enables increased performance but its low topography is crucial for introduction of sub 100 um thick cells in modules. The numerous interconnection points introduce redundancy, granting improved reliability. Last but not least, cost and aesthetics make this interconnection concept even more attractive for a wide variety of back contact and bifacial cell and module designs, and application such as Building Integrated PV.
This innovative approach has been recognized by both academic and industrial players in the field as one of the most innovative concepts of last years!
Challenges in this PhD will lie in the intersection of the cell and module design, hence a co-design in multiple aspects of the technology exploration will be the focus of this PhD. Co-design of the cell and module metallization will be indispensable to reach optimal performance at minimized material usage. At the same time to ensure long-term reliability of the cell interconnection, solder alloy and process selection in the co-design mindset will be crucial to avoid the formation of brittle intermetallic alloy. Therefore, close collaboration, and joint experiments with the reliability experts working on the same topic will be frequent. In parallel, the compatibility of the metallization with the polymeric encapsulant material and its impact on module reliability must be considered. Most experiments will demand combined electrical and material characterizations, and in certain cases development of tailored techniques. Additional critical constraints for material selection will arise from the demand of industrial weaving technology and module assembly. Finally, insight from imec’s bottom-up PV module energy yield simulation tool and field measurements could also provide critical guidelines for material and technological selection on the longer-term.
As illustrated by this description the challenges in this research project lie in the intertwined design, material and process selection requirements, and exploration/definition of these requirements. Therefore candidates fascinated by multi-disciplinary and hands-on research projects, and enjoying close collaboration with multiple experts are encouraged to apply.
You are curious, autonomous and dynamic. Enthusiastic to work in inter-disciplinary team. You are a team player with strong feeling for/experience in practical work.
Type of work:
15% literature study, 10% modeling, 75% experimental.
Daily advisor: Tom Borgers and Eszter Voroshazi
When you apply for this PhD project, mention the following reference code in the imec application form: ref. SE 1704-22.