Modeling of the resistive losses due to the bus-bar and external connections in III-V high-concentrator solar cells

A model for the analysis of the resistive losses due to current flow through the bus-bar and external connections, mainly focused on III-V high-concentrator solar cells, is presented. Initially, a formulation that takes two-dimensional current flow into account in the bus-bar is proposed for calculating the bus-bar equivalent resistance. Next, a simplification assuming a one-dimensional (1-D) current flow is considered and a fully analytical model is obtained. Then, both models are compared and the applicability range of the 1-D approximation is established. The model is then applied to the analysis of the inverted square grid with several configurations for the external connections. Finally, the potential of the model is illustrated with a set of simulations carried out using a 1000× concentrator GaAs solar cell and a number of conclusions of practical and technological interest are extracted.