Printing technologies for silicon solar cell metallization: A comprehensive review

This paper presents a comprehensive overview on printing technologies for metallization of solar cells. Throughout the last 30 years, flatbed screen printing has established itself as the predominant metallization process for the mass production of Silicon solar cells. For this reason, we will provide a detailed review on its history, its evolution over time and how the continuous efforts of the scientific and industrial community for further improvements revolutionized the entire PV industry. Furthermore, we will guide the reader through the physics on Silicon solar cell metallization, the fundamentals on contact formation and what type of challenges and requirements these topics create for printing technologies. The main topic of this review addresses the flatbed screen printing process mechanics, it´s different process sequences, corresponding screen technology and the very important impact of paste rheology on the printing result. Finally, we will compare alternative upcoming printing approaches to flatbed screen printing and discuss how they might solve upcoming challenges in metallization in terms of increasing the throughput rates at an ever decreasing grid line width and reduced silver consumption.