Traditional silicon solar panels with a hard glass coating have long followed the familiar standard of massiveness and durability. While the flexibility and lightness of roll-to-roll manufacturing have usually been associated with promising but still developing perovskite technologies, Italian researchers have proven that conventional silicon also has a future in flexible form. A team from the University of Padua and the Institute of Materials for Electronics and Magnetism of the Italian National Research Council (IMEM-CNR) has demonstrated a new process for manufacturing flexible silicon modules using hot plastic lamination.
The idea behind the development was to protect fragile silicon cells by multilayer polymer structures instead of massive and fragile glass sheets. For this purpose, the scientists used standard commercial silicon cells of the IBC (interdigitated back contact) type with a thickness of about 150 microns. The traditional glass was replaced with polyethylene terephthalate (PET), which serves both as mechanical protection and drastically lightens the entire module. The production process is fully adapted to the technology of continuous roller lamination (“roll-to-roll“), which promises a significant reduction in final production costs.
During the laboratory tests, the prototypes were assembled by hot rolling at a sealing temperature of about 390°C, heating the rollers to 130°C and a speed of passage of 9 millimeters per second. The results show that the drop in efficiency after lamination is only 4.4% compared to the initial value. Engineers determined that this minimal loss was not due to damage in the silicon itself, but to optical reflections in the boundary layer between the air and the PET coating - a problem that will be easily eliminated with the application of anti-reflective additives in the next phase of the project.
Mechanical resistance tests in a semi-bent state also confirmed the reliability of the technology. A single module withstood bending up to a radius of 95.4 millimeters without the appearance of new microcracks. A larger module of four elements (2x2 configuration) retained nearly 93% of its original power at a bending radius of 155 millimeters. In a 28-day outdoor test (total of 672 hours of exposure to weathering in a bent state), the prototype retained 96.12% of its efficiency, which is a clear proof of its structural strength.
The Italian research team is now in the final stages of optimizing the process. It is planned to replace the traditional soldering of the connecting wires with soldering technologies using special pastes, which are more suitable for roll production and do not create unnecessary mechanical stress at the contact points. The new technology has huge potential for implementation in building-integrated photovoltaics (BIPV), automotive, wearable electronics and the transportation sector, where conventional heavy glass panels are not applicable.