Modeling of an hybrid solar car with a lithium-ion battery

“Sunracers”, special solar cars using exclusively the electricity drawn from their embedded photovoltaic generator and designed to compete in solar races can be considered as special hybrid vehicles. This paper deals with the evolution of the serial hybrid architecture of the sunracer “Solelhada”. This new architecture, decoupling the bus voltage from the battery state of charge by means of an inserted reversible chopper between the battery and the DC bus, is designed to improve the energy management. Simultaneously, a new design of the battery is proposed, based on lithium-ion technology and meeting vehicle constraints and several races requirements. With the aim of predicting the vehicle behavior with its new battery, an original Bond Graph model of the whole vehicle system is proposed. Based on Bond Graph modeling, it includes an advanced battery model which is detailed in the paper. A special bench has also been performed in order to emulate the whole vehicle behavior during different races, taking into account the new architecture.