As a relatively new battery technology, lithium-ion had not been considered a viable alternative for use in high power applications, including energy storage for Hybrid Electric Vehicles (HEV). In 1996, Saft undertook a Phase I Research and Development program, funded by the US Department of Energy, under the sponsorship of the Partnership for a New Generation of Vehicles (PNGV), to determine lithium-ion applicability for HEV energy storage. During this program Saft determined that properly designed lithium-ion cells could exhibit outstanding power handling characteristics, excellent cycle life and concurrently, relatively high capacity. Using portable size cell hardware, Saft was able to demonstrate power handling capability of over 1200 W/kg, over 120,000 cycles of 3% DOD increment, and energy densities of 65-85 Wh/kg. The results of the Phase I program which were published during the EVS-14 Conference1 have shown that lithium-ion technology has the potential to be used as the primary energy storage device for HEVs. Saft has since begun a Phase II PNGV program to scale-up technology into full size cells and modules and to demonstrate their resilience under abuse test conditions.