Work

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

Year: 2026

Type: article

Abstract: FOILMET®-Interconnect-Shingling (FIS) is a crystalline silicon PV cell interconnection technologythat eliminates silver busbars, copper ribbons, tin-lead solder, and electrically conductive adhesive byjoining a 9 μm pure aluminum foil via laser scanning.Laser Metal Bonding (LMB) on TOPCon yields a higher adhesion with lower passivation impactcompared to application on PERC. Scaled to M10 1/6 production geometry, the estimated 𝑖𝑉OC dropis 1.4mV ± 0.9mV at a baseline 𝑖𝑉OC of 740mV (0.2% relative).A second-generation process decouples laser joining from cell positioning into tabbing andstringing steps, achieving a Foil Overlap of 200 μm at scan speeds up to 10 m∕s. Mechanicalregistration yields string length tolerances within ±300 μm independent of string length. The processis validated in M10 format and is compatible with bifacial cell architectures; assembly of an ∼2m2module confirms scalability.Cell to Module (CTM) simulations confirm that FIS uniquely combines the high CTM efficiencyof shingled interconnection – minimal inactive module area – with the high CTM power of ribboninterconnection – minimal cell area lost to overlap.

Source: Solar Energy Materials and Solar Cells

DOI: 10.1016/j.solmat.2026.114635

Authors: Jan Frederik Nekarda, Oliver John, Gernot Emanuel, Sophie Schneider, Max Mittag, Ralf Preu

Institutions: Fraunhofer Institute for Solar Energy Systems, University of Freiburg

Language: English

Topic: Silicon and Solar Cell Technologies

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

SDGs: Affordable and clean energy, Industry, innovation and infrastructure

Open Access status: hybrid

Estimated APC paid: $4,340