Optimized Interconnection of Passivated Emitter and Rear Cells by Experimentally Verified Modeling

Recent reports about new cell efficiency records are highlighting the continuing development of passivated emitter and rear cells (PERC). Additionally, volume production has started, forming the basis for cutting edge solar modules. However, transferring the high efficiency of the cells into a module requires an adaptation of the conventional front metallization and of the cell interconnection design. This paper studies and compares the module output of various cell interconnection technologies, including conventional cell interconnection ribbons and wires. We fabricate solar cells and characterize their electrical and optical properties. From the cells, we build experimental modules with various cell interconnection technologies. We determine the optical and electrical characteristics of the experimental modules. Based on our experimental results, we develop an analytical model that reproduces the power output of the experimental modules within the measurement uncertainty. The analytical model is then applied to simulate various cell interconnection technologies employing halved cells, optical enhanced cell interconnectors, and multiwires. We also consider the effect of enhancing the cell-to-cell spacing. Based on the experimentally verified simulations, we propose an optimized cell interconnection for a 60-PERC module that achieves a power output of 323 W. Our simulations reveal that wires combined with halved cells show the best module performance. However, applying light-harvesting structures to the cell interconnection ribbons is an attractive alternative for upgrading existing production lines.