Investigation of battery technologies for the army's hybrid vehicle application

A theoretical electrochemical cell is designed for the highest practical energy density. The materials are selected on the basis of bonding energies of the elements in the periodic table. It is shown that the physical limit to energy density of batteries is about 10-13 times larger than in the present lead-acid batteries, and an optimistic practical limit is approximately 450 Wh/kg. Based on the basic energy and power requirements of military vehicles and supposing that 25% is the maximum acceptable value of battery weight ratio to vehicle total weight, it is found that the proposed high energy density battery can support the vehicle highway driving at speeds of 70 mph for over 250 miles, and 15 miles at hill climbing at speeds of 6 mph. It is also found that with the best currently available batteries, the highway driving range is only about 105 miles, and hill climbing for about 6.4 miles. The study also shows that power capacities of batteries at present can meet the power requirement of the vehicle, even in hard acceleration.