On the way to higher efficiencies, back contact solar cells seem to be very promising. Especially, the metal wrap through (MWT) solar cell concept, with only three additional process steps when compared to conventionally processed cells, is appropriate for a fast transfer to industry. Hence, a pilot-line process based on a modified via-metallization step was set up. Therefore, a newly developed short suction step directly after the screen-printing process was established and characterized. Using this new via-metallization technique, cell efficiencies over 16% are reached on a multi-crystalline silicon (mc-Si) material. Compared with conventionally processed cells, an efficiency gain of 0.5% absolute is observed.

On the way to higher efficiencies, back contact solar cells seem to be a promising alternative to the conventional screen-printed solar cells. Especially, the metal wrap through (MWT) solar cell concept with only two additional process steps is appropriate for a fast transfer to industry. Hence, an industrially feasible process based on a new contact design was developed and tested at the pilot-line of the Photovoltaic Technology Evaluations Center (PV-TEC). A maximum cell efficiency of 16% is achieved. Compared with conventionally processed cells made of the same mc Si-block, an efficiency gain of 0.5% absolute is observed. Due to a cell interconnection on the back the serial resistance losses in the tabs decrease. Therefore, a fill factor of almost 77% and an efficiency of 15% for a MWT module prototype (16MWT cells) is reached.

On the way to higher efficiencies, back contact solar cells seem to be a promising alternative to conventional screen-printed solar cells. Especially, the MWT (metal wrap through) solar cell concept with only two additional process steps compared with the conventional cell process is appropriate for a fast transfer to industry. Hence, a pilot-line process based on a new contact design was developed and tested. Several batches of about 1000 mc-Si MWT solar cells were successfully produced at ISE's PV-TEC pilot-line. Cell efficiencies up to 16.2% are achieved with an emitter sheet resistance of 65 Ω/sq. Compared with conventionally processed cells made of the same mc Si-block, an efficiency gain up to 0.5% is observed. The main reason for the high efficiency is a high short circuit current due to the absence of the bus bars on the front. Furthermore, a cell interconnection only on the back is possible and thus less serial resistance losses in the tabs. Therefore, an additional efficiency gain of about 0.2%abs. compared with standard module technology is achieved using the new MWT tabbing technology.