A new 2.5D distributed spice model of solar cells

A general distributed circuit model of a solar cell has been developed for simulating a range of conditions. The model is based on standard equivalent circuits representing one- or two-diode models of a solar cell. In the new model, the full sized solar cell is modeled as a distributed, interconnected network of such equivalent circuits. Interconnecting resistors represent emitter series resistance, contact resistance, resistance in the metal grid and shunting resistance. This approach enables a realistic model of a solar cell with inhomogeneities as all resistor and diode parameters may be set separately for each element. As examples of usage three different cases were investigated. In one case the effect of uneven sheet resistivity is studied. The second case looks at the effect of broken metal fingers, and the third case looks at the effect of local shunts. Results using the model are obtained by SPICE simulations. This enables a fast calculation of current and potential distribution in the model circuit. Current and potential maps from a model solar cell consisting of several thousand elements may be calculated within seconds.