Formation and Orientational Distribution of Cracks Induced by Electromagnetic Induction Soldering in Crystalline Silicon Solar Cells

Soldering technology has major influence on the performance of crystalline silicon (c-Si) solar cells in the photovoltaic (PV) module. The mechanism of formation of cracks due to soldering is still highly debatable. In this paper, the formation and orientational distribution of cracks induced by electromagnetic induction soldering were investigated. For this purpose, the numbers of cracked cells and poorly soldered cells were counted, and different types of cracks and poor soldering were compared and analyzed. The results show that the diagonal crack is predominant in mono-c-Si cells, while the short crack perpendicular to bus-bar is the main type of crack in multi-c-Si cells. Moreover, the intersect crack is common in mono-and multi-c-Si cells. Thereafter, a model was put forward to explain the formation and propagation of cracks. Finally, the quality of electromagnetic induction soldering was investigated, which established that the defective cells, including cracks or poor soldering, constituted only about 0.4% of the total soldered cells.