Effect of finger interruption mode on the performance of crystalline silicon solar cells

Abstract

Research on the finger interruptions in the front side metallization of solar cells can help characterize the impact of finger fractures on solar cell performances. In addition, these findings can also predict the life of the photovoltaic (PV) modules that are affected by finger cracks. In the present study, we first established a model that studied the effect of finger interruption on solar cell resistance, in which two finger fracture modes, namely, continuous fracture and discontinuous fracture, were quantitatively analyzed. In addition, a set of mini-modules with finger interruption defects were also prepared, after which the impact of finger fractures on the solar cell performance was comparatively analyzed. According to the research results, the finger fracture affected the series resistance of the solar cell and output power by simultaneously changing the spatial distance of the finger and the number of fingers. The calculations showed that, for the continuously fractured finger, the average fracture of a single finger increased the average series resistance by 7.59 × 10-5 Ω and exhibited an average power loss of 0.0044 W. For the discontinuously fractured finger, a single finger fracture resulted in a higher average resistance of up to 5.36 × 10-4 Ω as well as an average power drop of 0.0058 W. We adopted a finger fracture percentage method to overcome complications with random finger fractures in the solar cell, after which the random fracture of the finger was analyzed. The finger fractures accounted for 10% and 20% of the total finger average solar cell power drops to −0.99% and −2.19%, respectively. Finally, for a 600 W PV module with 72 cells, 10% of the finger rupture resulted in a power loss of 5.94 W, and 20% of the finger rupture caused a power loss of 13.14 W. These results may aid research and engineering applications.