ENABLING REAR PASSIVATION FOR MASS PRODUCTION BY DEVELOPING SCREEN PRINTINGBASED REAR LINE CONTACT SOLAR CELLS

摘要

Over the last few years, large-area AlO_x/SiN_x stack rear passivated solar cells have been demonstratedin many R&D laboratories. The key point to achieve high-efficiency Passivated Emitter and Rear Contact (PERC)solar cells is to minimize the contact resistance while retaining the passivation performance at the rear surface. Thispaper reports on the development on the industrial scale of PERC cells based on laser ablation combined with screenprinting metallization technology. The impact of laser opening area to the passivation quality and contact resistance isinvestigated by changing the line width of laser openings. It is found that the effective lifetime increases withdecreasing the line width of laser ablation, while the series resistance stays constant in IV characteristics. Scanningelectron microscopy images also indicated that the local BSF is more homogenous with narrow line width. Theoptimum rear line contact scheme was achieved with a maximum cell efficiency of 19.6% for solar cells fabricated on156.5×156.5mm~2 p-type casting-mono silicon wafers, corresponding to an absolute gain of 1.0% compared to thereference cells with full area Al-BSF.