Pilot-line processing of Cz-Si MWT solar cells with an efficiency gain of 0,3%

The main objective of Bosch Solar Energy AG is the reduction of the production cost of PV modules. One approach is the development of high efficiency back contact solar cells. The Metal Wrap Through (MWT) solar cell concept is considered by Bosch Solar Energy AG to be a first and, in terms of additionally required process steps, least complex cell to realize the well known advantages of the back contact concepts. The primary advantages of the MWT concept are the current gain due to less metallization on the front side as well as an efficiency increase caused by the MWT module technology. Our intent is the transfer of the MWT concept to Cz- Silicon which is to our knowledge done for the first time on an industrial scale. In addition to solar cell and module results of MWT produced on Cz-Silicon, high cell efficiencies of mc-Si MWT, based on the same layout, are shown for comparison. With respect to conventional reference cells an efficiency gain of 0.3 % for Cz-Silicon MWT and of 0.5 % for mc-Si MWT with remarkable 16.8 % for the best mc-Si MWT cell could be shown.