Review on Metallization Approaches for High-Efficiency Silicon Heterojunction Solar Cells

Abstract

Crystalline silicon (c-Si) heterojunction (HJT) solar cells are one of the promising technologies for next-generation industrial high-efficiency silicon solar cells, and many efforts in transferring this technology to high-volume manufacturing in the photovoltaic (PV) industry are currently ongoing. Metallization is of vital importance to the PV performance and long-term reliability of HJT solar cells. In this review, we summarize the development status of metallization approaches for high-efficiency HJT solar cells. For conventional screen printing technology, to avoid the degradation of the passivation properties of the amorphous silicon layer, a low-temperature-cured (< 250 ℃) paste and process are needed. This process, in turn, leads to high line/contact resistances and high paste costs. To improve the conductivity of electrodes and reduce the metallization cost, multi-busbar, fine-line printing, and low-temperature-cured silver-coated copper pastes have been developed. In addition, several potential metallization technologies for HJT solar cells, such as the Smart Wire Contacting Technology, pattern transfer printing, inkjet/FlexTrailprinting, and copper electroplating, are discussed in detail. Based on the summary, the potential and challenges of these metallization technologies for HJT solar cells are analyzed.