Use of Cu ribbons and Cu-Ag HJT cell metallization on ECA based interconnection for PV modules

The availability of Silver is probably the main concern for PV cell's metallization and interconnection. It is then a critical element in most scenarios at the terawatt scale, reducing its usage is hence of prime interest. As a low temperature method, Electrically Conductive Adhesives (ECA) curing process has proved its worth in recent years. This interconnection technology shows also the advantage of high mechanical performances. This paper highlights the latest results obtained on the interconnection of HJT solar cells with ECA bonding material, focusing on the silver consumption reduction by the use of the latest generation of low-silver ECAs. In this study, three different ECA formulations were compared and investigated, ensuring their compatibility with ribbon coated by different conductive materials (Ag, SnAg and bare Cu). Finally, the introduction of Cu-Ag pastes for cell metallization was evaluated. We show that the new low-silver ECAs can even outperform previous-generation ECAs demonstrating higher performance and reliability. We also show a slight drop in performance of these new ECAs in combination with Sn/Cu ribbons, maintaining the reliability. Combining low-Ag ECAs with Sn ribbons can result in a silver content reduction of 6 mg/Wp, and even up to 8 mg/Wp with bare Cu ribbons to reach 14mg/Wp total consumption in the module. • PV module with less than 14 mg/Wp silver • Improved reliability with degradation in climatic chamber below 2 % after 2000h Damp Heat and 400 Thermal cycling • Lead and Bismuth free PV cell interconnection technology • Low temperature process adapted to HJT and Tandem cells