Backsheet Metallization of IBC Silicon Solar Cells

A simplified interconnection/metallization method for interdigitated back-contact (IBC) silicon solar cells is reported. A patterned PEDOT:PSS seed layer was inkjet printed on the backsheet. After curing, the seed layer pattern was electroplated first with Cu and then with eutectic Sn-Bi. During lamination at 150 degrees C, the eutectic Sn-Bi alloy melts and provides good ohmic contact between the IBC solar cells and the electroplated Cu on the backsheet, thus simultaneously achieving metallization and interconnection. The method eliminates the need to form thick metal conductors on the IBC cells. Furthermore, the moderate conductivity of the PEDOT:PSS seed layer lines results in tapered Cu conductors with the finger height reducing as a function of distance from the contacted busbar. This tapered metal grid can reduce the mass of Cu required for a 1% resistive power loss by 24%.