Characterization of the Laser Scribing Process of HIT Cells for a Photovoltaic Shingled Module

Shingled string technology can be used to maximize the output power of photovoltaic modules. The maximum power (P_max) of a shingled photovoltaic module can be increased by using a bifacial heterojunction with an intrinsic thin layer (HIT) of cells. To fabricate the shingled strings for a high power module, we first cut 6-inch solar cells by laser scribing while minimizing cutting loss. Unlike standard crystalline silicon (c-Si) solar cells, the structure of bifacial HIT solar cells is weak under thermal effect, so an optimal scribing condition had to be found. After laser scribing processes had been optimized, P_max was increased by 0.02W for each separated solar cells when we using an ultraviolet (UV) laser compared to the green laser, and a UV cut shingled string of HIT cell was demonstrated for the first time.