Innovative Front Grid Design, Four-Streets and Five-Busbars (4S-5BB), for High Efficiency Industrial Al-BSF Silicon Solar Cell

This letter reports on an innovative front grid design that is capable of: 1) decreasing the metal shading; 2) increasing the short-circuit current (JSC); 3) increasing the open-circuit voltage (VOC); 4) maintaining the fill factor; and 5) increasing the efficiency of an industrial Al back surface field (Al-BSF) solar cell. Because the design incorporates four-streets and five-busbars (4S-5BB), it uses less front silver metal (~73 mg) than the conventional 3BB (~129 mg), hence the cost reduction from 6.07 to 3.426 ⊄ per cell in metallization with no additional processing step. The 4S-5BB design has shown great potential for achieving >20% efficiency for the industrial size Al-BSF silicon solar cell. In this letter, the preliminary result for the 4S-5BB industrial Al-BSF cell having average efficiency of 19.66% compared with 19.3% 3BB counterpart is presented.