A Distributed Electrical Network to Model the Local Shunting in Multicrystalline Silicon Solar Cells

In this paper we propose a three-dimensional (3-D) distributed electrical network for the modelling of solar cells. The developed tool is based on a network of repetitive elementary cells, each modeled by a two-diode electrical circuit and allows to account for the transport through the emitter, the fingers and the busbars. Moreover, the tool is able to account for the non-uniformity in the solar cell. In order to validate our tool, we calibrate the electrical parameters according to experimental measurements on multicrystalline-silicon (mc-Si) solar cells. By using the thermographic analysis, we detect hot spot regions inside the mc-Si devices and we model them by means of local shunting in our tool. The presence of local shunting, due to localized crystal defects, results in a degradation of the open-circuit voltage, of the fill factor and then of the overall power conversion efficiency.