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The effect of charge rate was determined using constant-current (CC) and the USABC Fast-Charge (FC) tests on commercial lithium-ion cells. Charging at high rates caused performance decline in the cells. Representing the resistance data as ΔR vs. Rn-1 plots was shown to be a viable method to remove the ambiguity inherent in the time-based analyses of the data. Comparing the ΔR vs. Rn-1 results, the change in resistance was proportional to charge rate in both the CC and FC cell data, with the FC cells displaying a greater rate of change. Changes, such as delamination, at the anode were seen in both CC and FC cells. The amount of delamination was proportional to charge rate in the CC cells. No analogous trend was seen in the FC cells; extensive delamination was seen in all cases. These changes may be due to the interaction of processes, such as lithium plating and i2R heating.

Novel testing procedures and analytical methodologies to assess the performance of hybrid electric vehicle batteries have been developed. Tests include both characterization and cycle life and/or calendar life, and have been designed for both Power Assist and Dual Mode applications. Analytical procedures include a battery scaling methodology, the calculation of pulse resistance, pulse power, available energy, and differential capacity, and the modeling of calendar- and cycle-life data. Representative performance data and examples of the application of the analytical methodologies including resistance growth, power fade, and cycle- and calendar-life modeling for hybrid electric vehicle batteries are presented.

The successful commercialization of Electric Vehicles (EVs) and Hybrid Electric Vehicles (HEVs) can provide significant benefits by reducing the United States' growing dependence on petroleum fuels for transportation; decreasing polluting and greenhouse gas emissions; and facilitating a long-term transition to sustainable renewable energy sources. Recognizing these benefits, the U.S. Department of Energy (DOE) supports an active program of long-range R&D to develop electric vehicle (EV) and hybrid electric vehicle (HEV) technologies and to accelerate their commercialization. The DOE Office of Advanced Automotive Technologies (OAAT) supports several innovative R&D programs, conducted in partnership with DOE's national laboratories, industry, other government agencies, universities, and small businesses. The Office has two key R&D cooperative agreements with the U.S. Advanced Battery Consortium (USABC) to develop high-energy batteries for EVs and high-power batteries for HEVs.

Two recent workshops sponsored by the US Department of Energy are reviewed. The first focused on phenomena that limit performance of batteries, on understanding interfacial phenomena, on how to make stable interfaces, and on the role nanomaterials can play in batteries. The second provided a critical review of the current status of vehicle simulation models, battery performance models, and models that describe fundamental process occurring in batteries. The paper includes synopses of the papers presented as well as discussion of the conclusions and recommendations from the workshops.

This paper presents a summary of a recent conference entitled Advanced Lithium Solid State Batteries Workshop that was held on July 13–15, 1999. The conference was sponsored by the Department of Energy's Office of Advanced Automotive Technologies, and the Office of Basic Energy Sciences' (BES) Division of Chemical Sciences. This paper presents a summary of the results and recommendations from the conference, including: A review of current research on solid state electrolytes and their interfaces with an emphasis on both applied and basic studies. The research includes theoretical studies of solid polymer electrolytes (SPEs), lithium ion transport in SPEs, and simulations of the electrolyte–cathode interface. Experimental results are presented on ion transport phenomena in SPEs (NMR and X–ray) and mechanical stresses on electrodes, among other topics.

The United States supports an active research and development (R&D) program to develop electric and hybrid vehicle technologies and accelerate their commercialization. The U.S. Department of Energy (DOE), through its Office of Advanced Automotive Technologies (OAAT), supports the development of advanced energy storage and power electronics technologies, fuel cells, advanced direct-injection engines, vehicle systems, lightweight materials, and fuels. Much of this R&D directly supports the Partnership for a New Generation of Vehicles (PNGV), a landmark partnership between the U.S. Federal Government and automakers with the goal of developing a six-passenger family sedan with up to 80 miles per gallon (mpg) fuel economy by 2004. In these efforts, the DOE is working closely with its national laboratories, the auto industry and its suppliers, other government agencies, universities, and innovative small businesses. The Department continues to collaborate closely with the U.S.