Rotary Screen Printed Metallization of Heterojunction Solar Cells: Toward High-Throughput Production with Very Low Silver Laydown

Within this work, first bifacial silicon heterojunction solar cells with rotary screen printed front- and rear-side metallization are demonstrated. The high-throughput metallization process is carried out using an innovative rotary printing demonstrator machine with short process cycle times down to 0.65 s cell(-1). Furthermore, a very low total silver consumption of only 6-9 mg W-p (-1) for the fully metallized bifacial silicon heterojunction solar cells is demonstrated. Using a newly developed screen simulation approach, the utilized fine line rotary and flatbed screens are analyzed regarding their suitability for fine line metallization and verified using in-depth analysis of the geometrical and electrical properties of printed and cured metallization. The best group of fully rotary screen printed cells obtains a mean conversion efficiency of eta (RSP,avg) = 21.7% which is close to the flatbed screen printed reference group with eta (FSP,avg) = 22.1%. Using a hybrid approach with a rotary screen printed grid on the rear side and flatbed screen printed grid on the front side, a mean conversion efficiency of eta (hyb,avg) = 22.0% is obtained with a very low total silver consumption of only 9 mg W-p.