High rate comparison of lithium-ion, valve regulated lead acid, and nickel metal hydride batteries for use in pulsed power applications

Abstract

Electrochemical energy storage (EES) devices are steadily becoming more power and energy dense, bringing about the opportunity to more widely deploy them in high rate civilian and military applications. They are of special interest for use aboard future naval vessels on which high rate pulsed power loads will be fielded. EES devices traditionally operate at low voltages and modest current levels. Operating them at higher voltages and/or higher power rates often requires multiple cells to be interconnected in a series and/or parallel manner. The most common battery chemistries being considered for use in future pulsed power applications are valve regulated lead acid (VRLA), nickel metal hydride (NiMH), and lithium-ion (LI). At the University of Texas at Arlington's (UTAs) Pulsed Power and Energy Laboratory (PPEL), each of these chemistries has been evaluated at the cell or low voltage module level under a 5 second on/ 5 second off pulsed profile, as they may be used to drive future pulsed power applications. Metrics evaluated and presented here include power density, energy density, usable capacity, rate of capacity fade, and thermal evolution when operated at these high rates typically required of a directed energy system's prime power supply. Conclusions will be drawn to provide the reader with a better understanding of the role of each of these technologies in future pulsed power systems as well as design practices which can be followed based upon the lessons learned here.