Energy Storage for Hybrid Military Vehicles

The Challenge

Several types of batteries are being considered to meet the above described technical challenges in a vehicle energy storage system. The favored set of battery chemistries in the United States, in the order of decreasing interest, consists of rechargeable lithium, nickel-zinc, nickel metal-hydride, and lead acid. Other types of batteries are also being studied as future candidates. Programs are currently underway addressing investigations into failure modes, increasing energy density, reducing cost, and improving reliability.

For every problem arising from the battery management there are solutions. However, at the system level, a particular solution sometimes uncovers new problems or becomes the cause of other issues that need to be subsequently addressed. These unintended consequences are to be expected when dealing with the integration of complex systems.

Another consideration that will eventually have to be addressed is the operation and maintenance cost connected with hybrid electric power sources. Battery pack maintenance must be performed at the proper level of competence in the field. Maintenance procedures for dealing with battery pack replacement, cell replacement, and refurbishment still need to be worked out.

Future combat vehicles in the United States and other nations are expected to include hybrid electric platforms not because of single, well-identified benefits, but because of a combination of payoffs that has the potential to provide the soldier with expanded capabilities in both peace time and war time scenarios. The application of hybrid electric vehicles, and particularly AECVs, requires complex systems among which the energy storage system is quite challenging. Although the development and demonstration of advanced battery chemistry has been successfully demonstrated in the lab and on commercial vehicles, the demand of the power and energy for military missions and the integration of a functional, reliable, affordable, and safe system within an integrated power pack require intensive investigation and maturation before successful fielding of AECV.

This article was written by Ghassan Y. Khalil of the U.S. Army Research Development and Engineering Command in Warren, MI. Click here for more information.