Efficient Silver Usage in Screen-Printed SHJ Cells for the Terawatt Production Era

Enabling terawatt-scale silicon solar cell manufacturing requires a drastic reduction in silver usage without compromising performance. We demonstrate fine-line screen-printed silicon heterojunction (SHJ) cells using silver (Ag), silver-coated copper (AgCu), and copper (Cu) pastes on industrial precursors, delivering full-cell efficiencies around 23%, comparable to pure-Ag references. Specific Ag consumption drops to 2.1 mg/W_p (AgCu/AgCu) and 1.4 mg/W_p (AgCu/Cu). Fine AgCu grids printed with a nominal 17 μm screen opening on the wafer side achieve high effective Ag utilization of ∼25–30 cm²/Ω·mg. Cells with pure Cu paste metallization on both sides exhibited substantially lower J_SC and fill factor (FF). Cells were half-cut and integrated into modules via low-temperature, wire-based soldered interconnection; cutting and module-integration losses were assessed. Under accelerated thermal cycling of modules with cells based on Ag/Ag, AgCu/AgCu, as well as AgCu/Cu metallization, showed ≤2% relative efficiency loss, while Cu/Cu degraded by ∼7%. In module reliability testing, V_OC and J_SC remained stable, while the degradation was dominated by FF losses due to increased series resistance, partially explained by occasional wire detachment. These results show that SHJ cells with AgCu/AgCu or AgCu/Cu metallization can meet Terawatt (TW)-era Ag constraints and deliver SHJ modules with substantially lower Ag consumption compared to typical tunnel oxide passivated contact (TOPCon) cells and modules, which require ∼7 mg/W_p.