RENA’s ‘InCellPlate Cu’ inline equipment for direct plating of a Ni/Cu/Ag stack on silicon, when combined with laser ablation of the silicon nitride layer and subsequent inline anneal, is said to provide complete front-side metallization for solar cell manufacturing. Compared with screen-printing, the technology allows cutting the cell production cost by US$0.06 (cents) and at the same time offers potential for cell efficiency improvement.
Conventional screen printing of the front contacts remains among the most costly processes in solar cell manufacturing and at the same time limits the achievable finger width and emitter sheet resistance and so limits the overall cell performance.
Direct plating on silicon with RENA’s InCellPlate Cu makes the use of screen-print paste on the front side obsolete. It further replaces most of the silver with cheaper copper as a conductive metal, which is claimed to reduce costs per cell by US$0.06 (cents). Furthermore, the technology allows the formation of thinner fingers (≤30 μm) and contact formation to emitters with higher sheet resistance (≥120 Ohmsq.), thus enabling higher currents and voltages while keeping the fill factor high. RENA has already successfully demonstrated the technology, reaching 20.8% efficiency on Cz-PERC cells (verified by ISE Cal-Lab). Modules made with this technology successfully passed more than three times the IEC61215 test procedures and the soldered strings showed outstanding adhesion properties(>1N/mm), according to the company.
Solar cell processing, front side contact formation.
The InCellPlate Cu is based on RENA’s proven NIAK inline platform for up to 3600w/h throughput. RENA’s patented technology allows single side plating of the cell’s sunny side while keeping the rear-side dry. This reduces the drag-out of electrolyte and associated production costs, avoids undesired plating of the contacts and excludes the risk of degradation of the aluminum paste by contact with the electrolyte.