Patterning for Plated Heterojunction Cells

This paper describes a patterning and plated metallization process that can be used for bifacial heterojunction silicon solar cells. Patterning was achieved by inkjet printing a functional fluid onto a resist surface, the fluid being able to chemically inhibit resist cross-linking in a subsequent thermal process. Copper/tin plated fingers as narrow as 20 μm were achieved on both surfaces of the cell. The low temperature metallization process was demonstrated on 156 mm heterojunction cells where the finger metallization was interconnected using SmartWire Connection Technology resulting in mini modules with efficiencies as high as 18.8%.