Intense Pulsed Light Sintering of Screen-Printed Paste Electrode on Silicon Solar Cell for High Throughput and Cost-Effective Low Temperature Metallization

The silver (Ag) coated copper (Cu) paste were printed and sintered on silicon (Si) heterojunction solar cell via continuous intense pulsed light (IPL) as an electrode. The temperature of the electrode was monitored by thermocouple and infrared (IR) camera during IPL sintering process. To grasp more accurate temperature profile, a heat transfer simulation was also conducted by finite difference method. The line resistivity and contact resistivity of Ag coated Cu electrodes were evaluated with respect to light energy and the optimal IPL process parameter were chosen as light energy of 6 J/cm(2) and 5 cm/s conveyor belt speed. I-V curve of the Si solar cell was measured and there was only 0.2% reduction in efficiency compared to conventional Ag thermal cured electrodes. The efficiency was decreased slightly due to the decrease in the short circuit current (Jsc). It is noteworthy that the open circuit voltage (Voc) of the Si solar cell with IPL sintered Ag coated Cu paste, increased by 2 mV because the surface passivation was improved by light exposure. In addition, it was confirmed that there is no Cu diffusion problem by measuring the pseudo fill factor (pFF) for 6 months to secure the reliability of the solar cell.

Automated summary

Silver-coated copper paste sintered on silicon heterojunction solar cells via intense pulsed light (IPL) can improve electrode efficiency, increase open circuit voltage, and has been confirmed to be reliable through long-term testing.