Optimization of Multi-Layer Metallization Design for Large-Area Back-Contact Back-Junction Solar Cells

Abstract

In this study, a multi-layer metallization concept for high-efficient large-area silicon back-contact back-junction solar cells is investigated. The metallization approach represents an industrial alternative to the well-known edge-to-edge cell interconnection technology, allowing for a decoupling of the cell metallization from the external contact structure by inserting an intermediate insulation layer. A first proof of principle is shown for an n type back-contact back-junction solar cell with an edge length of 156 mm and evaporated aluminum grid fingers. Furthermore, we present a tool that allows for the design optimization of the contact layout by combining detailed cost of ownership calculations with analytical solar cell simulations. Two back-end process sequences are compared and for both approaches the most cost-effective metallization layout is determined on cell level. Finally, a sensitivity analysis is carried out, revealing the high potential of the investigated back-contact back junction solar cell structures.