Inhomogeneity of Plated Contacts for c-Si Solar Cells and Their Impact on Solar Cell Efficiency

Abstract

Plating is an emergent cost-effective metallization technology for depositing solar cell metal contacts. Plated contacts, however, typically plate in-homogeneously where fingers plate higher than busbars and solar cell edges plate particularly higher. The impact of these systematic inhomogeneities on solar cell efficiency and total plated mass is not yet well understood. To generate plating distributions, this work proposes a purely resistive plating simulation approach, employing the solar cell simulator Quokka3, which is validated by reproducing a variety of experimentally observed inhomogeneities. A simulation pipeline is then used to show the impact of initial grid and tool design on plated height distributions, as well as their impact on solar cell efficiency and total plated mass. As such, simulation shows that large-scale inhomogeneities, i.e., increased plating toward cell edges, can be avoided by adjusting the design of the anode and bath and/or reducing the cell-to-cell distance in an inline plating tool. Furthermore, results suggest that finger height inhomogeneity does not significantly reduce the maximum achievable cell efficiency, whereas it can significantly lower the plated mass required to reach that efficiency. This implies that systematic finger height inhomogeneities typical for plating could be acceptable if not beneficial for the dollar-per-watt tradeoff between cell efficiency and total deposited mass.