FOILMET®-Interconnect-Shingling: A silver-, copper-, lead-, solder- and adhesive-free cell interconnection technology for crystalline silicon PV based on laser-joined pure aluminum foil

Abstract

FOILMET®-Interconnect-Shingling (FIS) is a crystalline silicon PV cell interconnection technology that eliminates silver busbars, copper ribbons, tin-lead solder, and electrically conductive adhesive by joining a 9 µm pure aluminum foil via laser scanning. Laser Metal Bonding (LMB) on TOPCon yields a higher adhesion with lower passivation impact compared to application on PERC. Scaled to M10 1/6 production geometry, the estimated i V OC drop is 1.4 mV ± 0.9 mV at a baseline i V OC of 740 mV (0.2 % relative). A second-generation process decouples laser joining from cell positioning into tabbing and stringing steps, achieving a Foil Overlap of 200 µm at scan speeds up to 10 m/s. Mechanical registration yields string length tolerances within ± 300 µm independent of string length. The process is validated in M10 format and is compatible with bifacial cell architectures; assembly of an ∼ 2 m 2 module confirms scalability. Cell to Module (CTM) simulations confirm that FIS uniquely combines the high CTM efficiency of shingled interconnection – minimal inactive module area – with the high CTM power of ribbon interconnection – minimal cell area lost to overlap.