Progress on the reduction of silver consumption in metallization of silicon heterojunction solar cells

In this work, we have demonstrated the possibility to reduce silver consumption for highly efficient SHJ cells by fine-line screen printing using low temperature paste with a variety of screens with different meshes and openings. The achieved grid fingers were characterized for the line resistance and the printed width. Extremely narrow grid fingers with 13 mu m width were realized on the 520-mesh. Compared to a standard 380-mesh, finer 520-mesh produced fingers that are on average 4 mu m narrower and 8% less resistive, leading to a 0.08%abs. higher efficiency whilst reducing the overall silver consumption by 15%. Complementary simulations have shown that module wire configuration is an important driver to reduce silver consumption. Integration of test samples in modules showed that 1.6 mg/W frontside paste laydown resulted in marginally lower performance than reference samples with laydown of 4-6 mg/W.