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This paper mainly uses laser technology to study the back slotting of PERC (Passivated Emitter and Rear Cell) solar cells. The high-speed laser scanning device based on the polygon mirror can effectively improve the slotting efficiency of PERC solar cells in current industrial processing. The rotating speed of the polygon mirror is 11400 rpm. The focus lens adopts a long focal length of 420 mm, so the maximum scanning speed can be 1000 m/s, the laser power is 500 W, the pulse repetition rate is 500 kHz, the wavelength is 1064 nm, the pulse width is 120 ns, and the size is 100 mm × 100 mm solar cell is scanned and processed 12 times, the scanning speed is 500 m/s, the surface treatment is about 10201 micro-holes the hole depth is 130 nm, and it only takes 0.8 seconds. The theoretical and experimental research shows that this technology will significantly improve the industrial slotting efficiency of the solar cell. In addition, the passivation layer of PERC solar cells mainly adopt slotting and perforating in industry. The former technology is relatively mature but will lose much passivation film area to increase the carrier recombination rate, and the latter industrial processing efficiency is low. While sintering the back electrode, it is easy to produce a "hole" in the back electrode to increase the series resistance of the solar cell, thus affecting the conversion efficiency of the solar cell itself. In this paper, we use the polygon mirror laser scanning device to slot the back surface of the solar cell. At the same time, we also designed a "back dotted line" slotting of the solar cell. Compared with the straight-line slot, the dotted line slotting increases the solar cell's short circuit current and open circuit voltage. It ultimately improves the photoelectric conversion efficiency by 0.04%.
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