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Within this work, first bifacial silicon heterojunction solar cells with rotary screen printed front‐ and rear‐side metallization are demonstrated. The high‐throughput metallization process is carried out using an innovative rotary printing demonstrator machine with short process cycle times down to 0.65 s cell−1. Furthermore, a very low total silver consumption of only 6–9 mg Wp−1 for the fully metallized bifacial silicon heterojunction solar cells is demonstrated. Using a newly developed screen simulation approach, the utilized fine line rotary and flatbed screens are analyzed regarding their suitability for fine line metallization and verified using in‐depth analysis of the geometrical and electrical properties of printed and cured metallization. The best group of fully rotary screen printed cells obtains a mean conversion efficiency of ηRSP,avg = 21.7% which is close to the flatbed screen printed reference group with ηFSP,avg = 22.1%. Using a hybrid approach with a rotary screen printed grid on the rear side and flatbed screen printed grid on the front side, a mean conversion efficiency of ηhyb,avg = 22.0% is obtained with a very low total silver consumption of only 9 mg Wp. [ABSTRACT FROM AUTHOR]

Today's photovoltaic production chain is moving into a material crisis as the use of silver for front‐side metallization of passivated emitter and rear contact solar cells remains a crucial requirement. The shared effort of the scientific and industrial community to further reduce Ag‐consumption as much as possible without compromising cell efficiency has become more challenging in recent years. Further improvements require a deep understanding on the paste‐screen interaction at narrow line widths. This study presents the impact of Ag‐paste rheology on fine line screen printing for screen openings between 15 and 24 µm at industrial printing speeds of up to 600 mm s−1. A clear trade‐off is there between maintaining a sufficient reproducibility of the screen printing process and achieving an optimized printed Ag‐electrode geometry, thus optimal Ag‐consumption. Further, a correlation between the work of adhesion at the paste–wire interface and the resulting deviation of the printed electrode height is discovered, highlighting the importance of an advanced screen optimization for the future of fine line screen printing. Finally, an easy to use method for analyzing the reproducibility of printed Ag‐electrode geometries even for lab‐scale data sets is presented. [ABSTRACT FROM AUTHOR]

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 wn = 15 μm. The best experimental group achieved a record finger geometry with a mean finger width of wf = 19 μm and a mean finger height of hf = 18 μm. Furthermore, solar cell performance using a front‐side grid with a screen opening width of wn = 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 FROM AUTHOR]

This study presents a new developed, inline applicable dispensing platform that is equipped with an advanced version of previously introduced parallel dispensing print heads and works as drop-in-replacement in existing manufacturing lines. At process speeds of up to 700 mm•s-1 and a substantially improved process stability, the impact of the resulting contact geometries on optical and ohmic losses was analysed in detail. A reduced finger width as well as an effective width of just 48% after encapsulation of the finger width leads to nearly 50% reduction of shading losses compared to screen printed samples. A substantially improved finger homogeneity leads to similar grid resistances at 20% less silver consumption. Consequently, recent cell results on industrial emitters (R sh = 90 Ω/sq.) showed an efficiency increase of up to +0.4%abs. in comparison to standard single screen printing reaching top values of η = 20.5% on PERC structures. A key improvement of the technology is the new ability to process certain metal pastes originally designed for screen printing applications and thus keep in track with fast emerging paste development. Successfully evaluated screen printing pastes then can be rheologically adapted in order to reach ultrafine contact fingers at high aspect ratios and extract the whole advantage of this non-contacting printing technology. [ABSTRACT FROM AUTHOR]