Screen pattern simulation for an improved front‐side Ag‐electrode metallization of Si‐solar cells
Sebastian Tepner, Linda Ney, Michael Linse, Andreas Lorenz, Maximilian Pospischil, Kenji Masuri, Florian Clement
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.