Screen pattern simulation for an improved front‐side Ag‐electrode metallization of Si‐solar cells. (13th July 2020)

• Record Type: Journal Article
• Authors: Tepner, Sebastian; Ney, Linda; Linse, Michael; Lorenz, Andreas; Pospischil, Maximilian; Masuri, Kenji; Clement, Florian
• Is Part Of: Progress in photovoltaics. Volume 28:Number 10(2020)
• Page Start: 1054
• Page End: 1062
• Publication Date: 2020-07-13
• Subjects: screen printing -- knotless screens -- Si‐solar cells -- metallization -- screen simulation; Solar cells -- Periodicals; Photovoltaic cells -- Periodicals; Solar power plants -- Periodicals; 621.31245
• DOI: 10.1002/pip.3313
• Languages: English
• ISSNs: 1062-7995

Abstract

Abstract: Flatbed screen printing proves to be the dominant metallization approach for mass production of silicon (Si)‐solar cells because of its robust and cost‐effective production capability. However, the ongoing demand of the PV industry to further decrease the width of printed Ag‐electrodes (contact fingers) requires new optimizations. This study presents the latest results on Si‐solar cell metallization using fine‐line screens down to screen opening widths of w n = 15 μm. The best experimental group achieved a record finger geometry with a mean finger width of w f = 19 μm and a mean finger height of h f = 18 μm. Furthermore, solar cell performance using a front‐side grid with a screen opening width of w n = 24 μm is investigated, reporting cell efficiencies up to 22.1% for Passivated Emitter and Rear Contact (PERC) solar cells. Finally, a novel screen pattern simulation is presented, revealing a correlation between the measured lateral finger resistance and the novel dimensionless parameter screen utility index (SUI). It describes the ratio between the average size of individual openings defined by the screen mesh angle and the chosen underlying mesh type. For SUI < 1, the printing result will strongly depend on the screen configuration, whereas for values of SUI > 1, the impact of the screen on the overall printability diminishes. Abstract : This work presents a novel screen pattern simulation to further improve screen printed metallization of solar cells. Simulation results suggest that the screen angle has a significant influence on the expected printing result. It was possible to achieve a finger width of 19 μm at a height of 18 μm with an average lateral finger resistance of 270 Ω /m. Further, PERC front‐side metallization using a 440/0.013 knotless screen resulted in a cell efficiency of up to 22.1%.