Investigation of laser pattern for high efficiency PERC mono silicon solar cells

In this work, we proposed the impact of the rear laser process design applied to screen-printed passivated emitter and rear cell (PERC) structure. We compared different laser pattern design 1) line (reference), 2) Dash (2∶1), and 3) Dash (5∶1) on a high-efficiency level using 156 mm × 156 mm p-type Cz mono silicon wafer. It can be found that employing the laser pattern of dash 2:1 outperforms all other laser pattern due to its excellent aluminum back surface field. The average open-circuit voltage of the laser pattern of Dash 2∶1 PERC solar cells is also larger than all other opening ratio solar cells. Besides, by using the laser pattern of Dash 2∶1 PERC solar cells, the conversion efficiencies of 20.6% for the best PERC solar cell and 20.4% for the average of PERC solar cells are measured. Besides, the PERC solar cells also passed the PID test which condition was indicated to be 85 degree Celsius and 85% RH in climatic chamber for 96 hours. Observed the power loss < 3% and no EL darkened area were found after PID test for the PERC solar cells.