Modeling the Performance of Lithium-Ion Batteries for Fuel Cell Vehicles

This study involves the battery requirements for a fuel cell-powered hybrid electric vehicle. The performances of the vehicle [a 3200-lb (1455-kg) sedan], the fuel cell, and the battery were evaluated in a vehicle simulation. Most of the attention was given to the design and performance of the battery, a lithium-ion, manganese spinel-graphite system of 75-kW power to be used with a 50-kW fuel cell. The total power performance of the system was excellent at the full operating temperatures of the fuel cell and battery. The battery cycling duty is very moderate, as regenerative braking for the Federal Urban Driving Schedule and the Highway Fuel Economy Test cycles can do all charging of the battery. Cold start-up at 20°C is straightforward, with full power available immediately. Cold start-up at -20°C is more difficult, but can be accomplished by the use of thermal storage in the form of 10 L of transformer heat-transfer fluid heated to 180°C, which can warm the battery to 10°C and restore the battery to full power within two minutes.