Polyimide Knotless Screen for High Efficiency Heterojunction Solar Cells Mass Production

Bianca Passarella1, Florent Pernoud2, Alfredo Di Matteo1, Alessandro Furnari1, Marcello Sciuto1, Renaud Varache2, Francesco Rametta1, Cosimo Gerardi1, Diego Di Girolamo1 13SUN S.r.l., Catania, --, Italy /2Univ. Grenoble Alpes, CEA, LITEN, INES, Le Bourget du Lac, --, France

Crystalline silicon (c-Si) heterojunction (HJT) solar cells are one of the most promising technologies for next-generation industrial high-efficiency silicon solar cells. Metallization plays an important role to the photovoltaic performance and manufacturing cost of HJT solar cells. In this work more uniform and narrower fingers’ profiles have been demonstrated using a combination of screen optimizations: knotless meshes, polyimide (PI) film instead of liquid emulsion, narrow mesh wire diameter and small screen opening. With these improvements, important gains have been obtained in terms of line resistance, fingers width, cell efficiency due to less shading and silver deposit. The results of this work have been then transferred to industrial level wafers and some major screen suppliers were tested to confirm the improvements demonstrated. Higher efficiency, good printability and deposit consumption as low as 14 mg have been demonstrated.