A comparative experimental study on front and back laser cutting technology for mass separation of N-TOPCon crystal silicon solar cells

Generally, the Thermal Laser Separation (TLS) technology is used to pre-groove from the back of the cell, which is the first process of half-cell module preparation. However, this benchmark practice may result in forming new leakage points in the grooves at both ends of the cell. Hence, we investigate the mechanism behind the formation of leakage points after grooving and the impact on N-TOPCon's cell efficiency and module power. It is discovered that the diffusion of P element is the main reason for the increase in the proportion of leakage points. The front cutting is accordingly proposed to alleviate problem. A comprehensive experimental study on its feasibility has been conducted. It has been confirmed that the leakage current under the reverse bias voltage is smaller, the data convergence is better, and the breakdown performance is more stable for N-TOPCon. Furthermore, the module power is higher.