Several types of batteries have been investigated for use in EVs and HEVs, among them lithium-aluminum-iron-sulfide, nickel-metal hydride, lithium-ion, and lithium-polymer. Lithium-ion systems come closest to meeting all of the technical requirements, but they face four barriers: calendar life, low-temperature performance, abuse tolerance, and cost. This work has produced a number of documents for developers, which are available from the USCAR Electrochemical Energy Storage Tech Team Website.