R&D pilot-line production of multi-crystalline Si solar cells with top efficiencies exceeding 19%

In this paper we report on latest results from our pilot production of multi-crystalline (mc) p-type Si cells in the Reiner-Lemoine Research Center at Q-Cells. The cells are double-side contacted and feature a lowly doped emitter, a fineline-printed Ag grid in combination with plating as front metallization and a dielectric passivated rear with local contacts. Using material based on Siemens and upgraded metallurgical grade (100% UMG) feedstock, we achieve stable median cell efficiencies of well above 18 % including the whole brick distribution. Top efficiencies exceeding 19 % (total area) are reached with a standard isotextured front and single anti-reflexion coating. In this work, we show the latest cell optimization progress corresponding to the front metallization process. Furthermore, we report on an independently confirmed cell efficiency of 19.5 % on a large-area multi-crystalline Si solar cell (243 cm2). This efficiency was achieved by implementing next generation process steps. To our knowledge, this result represents the highest energy conversion efficiencies on multi-crystalline Si material achieved so far.