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In this paper, we analyze the effect of local shunts in photovoltaic (PV) solar cells by experimental characterization and distributed electrical simulations. To this purpose, we developed a quasi-3-D distributed electrical network that is based on two-diode circuit elementary units. It allows accounting for resistive losses as- sociated to the transport through the emitter, the fingers and the busbars, and to local defects in the semiconductor. The electrical parameters of the equivalent circuit units are calibrated according to experiments performed on multicrystalline (mc-Si) silicon solar cells, including samples that feature local shunts due to localized defects, which lead to nonuniform distribution of electrical and optical properties. The distributed electrical simulations account for the degradation of fill factor and power conversion efficiency in case of local shunting. Moreover, by combining the proposed tool with a RC thermal network it is possible to estimate the tempera- ture distribution in a shunted solar cell. Our analysis shows how a shunted cell that operates under hot-spot conditions is subject to significant local overheating, which possibly lead to permanent PV cell damages

In this paper, we model a large-area high-efficiency interdigitated back-contact (IBC) solar cell by means of a distributed electrical network. The simulation tool allows accounting for the distributed resistive effects in diffusions and metallization. The model also considers the electrical shading effect and resistive losses due to both back-surface field (BSF) and emitter busbars. A calibrated model is used to investigate the case of a large-area (15.6 × 15.6 cm2) IBC cell, in which we investigate the influence of key busbar parameters: number of busbars, busbar width, soldering pitch (for module connection), and metal sheet resistance. The predictive simulations allow finding out the optimum number of busbars, arising from a tradeoff between the electrical shading effect due to the BSF busbars and resistive losses due to the emitter busbars and the fingers. Moreover, we show how the distance between soldering points on the metal busbars influences the choice of the busbar width. We found out that if an adequate number (>7) of soldering points is adopted, the busbar width should be kept lower than 0.5 mm. On the other hand, the adoption of a thick Cu-plating (15 μm) leads to an increase of efficiency of 0.2%abs with respect to the case of sputtered Al metal (3 μm thick)