Transition to 4 and 5 BB Designs for Ni/Cu/Ag Plated Cells

The aim of this work was to demonstrate the advantages of the Ni/Cu/Ag plating process when the number of busbars on the solar cell is increased. Cells with four and five busbars were processed and compared to those with three in respect of efficiency, finger and solder adhesion. It is shown that the efficiency can be increased by 0.15%, while the finger adhesion remains the same or improves and the solder adhesion remains mostly greater than 1 N/mm2, if the number of busbars is increased from 3 to 4 or 5. The mass of metal deposited can be reduced by up to 30% for 5 busbars compared to that required for 3 busbars. Furthermore, it is estimated that the cost of metallisation can be reduced from 9 €ct/wafer for three busbars to 8.6 €ct/wafer for five busbars.