»FoilMet« process for 30 percent silver savings in module production

A research group at the Fraunhofer Institute for Solar Energy Systems ISE in Freiburg, Germany has developed a laser welding process called »FoilMet« that can interconnect solar cells in PERC or TopCon technology without the usual busbars. Instead, a thin aluminum strip placed on the silicon nitride surface in the area between the contact fingers is being used to interconnect the cells.
According to ISE, up to 30 percent of silver can be saved in the production of solar modules, »depending on the electrode layout«, because the cells do not need busbars in this process. In addition, the comparatively inexpensive aluminum replaces the soldered joints or adhesives that would otherwise be required. The former require copper and leaded solder, the latter also silver.
Moreover, the FoilMet process is characterized by high mechanical strength. It can therefore be used both for conventional module layouts with cells placed next to each other – at very close distances – and for »shingled« modules with overlapping (half) cells. A curved design of the cell strings, for example for integration in uneven surfaces, is also possible.
© PHOTON