How to achieve 17% cell efficiencies on large back-contacted mc-Si solar cells

It is demonstrated that back-contacted PUM modules made with industrially applicable processes will result in at least 0.8% absolute higher efficiencies than modules manufactured with conventional H-pattern cells. At the cell level, this advantage is about 0.3% absolute, which is almost entirely related to the 2% larger short-circuit current of PUM cells due to less front-side metallization coverage. After interconnection and lamination, at least an additional 0.5% absolute efficiency gain for PUM was obtained because of the lower series resistance losses in the PUM concept. The more efficient current collection over the cell area and the possibility of using wider interconnection material at the rear are the reasons for the lower resistance losses. The stability of the in-line PUM process using simple belt furnaces was demonstrated on a batch of more than 350 cells. The average efficiency for PUM cells is 15.8% with a top efficiency of 16.7%