Development of Copper Electroplating Technique for Silicon Heterojunction Solar Cells with Efficiency over 23.1%

29th European Photovoltaic Solar Energy Conference and Exhibition; 1352-1354
A conversion efficiency of 22.75 % for silicon heterojunction (SHJ) solar cells using standard 40 um finger width of copper electroplating process has been successfully achieved in our RD line at AU Optronics (AUO). However, 40 um finger width of copper (Cu) electroplating (EP) technique has encountered difficulties for further efficiency improvements. Our power loss simulation reveals efficiency gains from fine fingers. AUO solar RD team has been developing a new manufacturing technology by employing 20 um finger width of Cu EP to improve shortcircuit current. Both the experimental result and theoretical calculation show that the total power loss of 20 um finger width and optimum TCO film resistance of Cu EP cells is much smaller than the power loss from the state of 40 um finger width technique. According to the simulation result, an efficiency of more than 23.1% is achievable by our unique metallization technique.