Comprehensive Empirical Model for Evaluation of the Series Resistance of a Solar Cell

This paper reports on the empirical model for series resistance (R-s) of a screen-printed silicon solar cell with segmented metal grids. Due to the quasi-Gaussian shape of grid line cross section, a mathematical expression of the practical cross section of grid line was implemented instead of the simple rectangular shape. And segmentations of gridlines and busbars were introduced to assess the impact on series resistance and solar cell performance. The advantage of this evaluation can be taken to determine the optimal metal grid design in terms of grid geometries and distributions of metal electrodes. It was found that for an industrial size monocrystalline silicon solar cell with 3 busbars having a width of 1.5 mm, and 92 gridlines of similar to 50 mu m width, the optimal segmentation for grid lines should be similar to 0.67 mm, and for busbars should be the line spacing. A further study reveals that the segmentations in busbars has much larger impact on efficiency than gridlines.