3D-Micromac, from Chemnitz in Germany, has developed a new laser system for opening PERC photovoltaic cells for further processing during manufacture.
The company has developed a new way of opening rear-side-passivated cells (PERC, passivated emitter rear contact). This is a type of photovoltaic cell made of crystalline silicon that has special, optimised rear-side passivation, whereby the 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 the rear sides of the cells.
3D-Micromac's innovative on-the-fly technology makes it possible to achieve an impressive cost-benefit ratio. The system is modular, combinable with different laser-source technologies, and achieves a typical efficiency increase up to one percentage point.
Elaborate handling and individual positioning procedures of the cells are eliminated. The cells are now 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. The system is being initially offered as a stand-alone variant; however it can also be completely integrated into existing production automation.