3D-Micromac has developed a novel, highly productive laser system for opening the rear sides of PERC cells. Innovative on-the-fly technology makes it possible to achieve an improved cost-benefit ratio. The system is modular, combinable with different laser-source technologies, and achieves a typical efficiency increase up to one percentage point.
PERC cells are photovoltaic cells made of crystalline silicon having special, optimized rear-side passivation. A PERC cell's rear side is completely coated with a non-conductive, dielectric SiOx/SiN or AIOx/Sin layer. The task is to open this layer with the aid of point or line patterns using lasers without damaging the underlying silicon in order to later apply a metal layer for contacting.
3D-Micromac relies on its ‘on-the-fly’ technology, which is claimed to offer the highest productivity with an excellent price-performance ratio, leading to an increase in cell efficiency by up to 1%. The productivity advantage is due to the handling and individual positioning procedures of the cells which are eliminated. The cells are instead transported under the laser source on a conveyor belt, which renders alignment stops superfluous. The integrated optics automatically compensates for the cells' relative motion and scribes exactly the desired pattern into the cell's sensitive rear side.
PERC cell passivation.
The system is being initially offered as a stand-alone variant; however it can also be completely integrated into existing production automation. The structuring platform from 3D-Micromac is also suitable for processing of selective-emitter, MWT, and EWT cells.
August 2013 onwards.