To develop better lithium-ion (Li-ion) batteries for plug-in electric vehicles, researchers must integrate the advances made in exploratory battery materials and applied battery research into full battery systems for vehicles. The Vehicle Technologies Office's (VTO) Advanced Battery Development, System Analysis, and Testing activity focuses on developing battery cells and modules that result in significantly lower battery cost, longer life, and better performance to meet the EV Everywhere Grand Challenge's goal. VTO coordinates activities with the U.S. Advanced Battery Consortium (USABC), a group run by the industry organization the United States Council for Automotive Research (USCAR). It also works directly with industry battery and material suppliers through competitive research and development awards. To understand how batteries work in general, see the Energy Basics page on Batteries. To learn how batteries are used in plug-in electric vehicles, visit the Alternative Fuels Data Center's page on batteries.
Through the USABC, VTO supports a variety of research, testing, and benchmarking. The group helped develop a number of test procedure manuals, which are available from the USCAR Electrochemical Energy Storage Tech Team Website. Repeatable test procedures allow researchers to consistently evaluate batteries on key characteristics such as cycle life and abuse tolerance. Benchmark testing for batteries sets a base level to which companies can reliably compare their improvements on a constant basis.
VTO has also supported work to develop models that help researchers design and calculate potential costs of batteries. One major model is the bottom-up Battery Performance and Cost Model (BatPaC) at Argonne National Laboratory, which includes cost assumptions for materials chemistry, design, and manufacturing process. The free, public domain model is designed for policy makers and researchers to estimate costs once Li-ion batteries have reached a mature state of development and manufacturers are producing them at high volume. BatPaC has more accurate predictions than previous models and allows vehicle manufacturers to choose the best and smallest battery for the application. Based on expert recommendations of this model, the U.S. Environmental Protection Agency used BatPaC to develop its most recent round of fuel economy standards. In addition, work at the National Renewable Energy Laboratory (NREL) led to a multi-scale multi-dimensional framework for battery design that uses computer-aided engineering tools.
Other research supported by VTO has helped develop battery cells and modules that help reduce battery cost, increase battery life, and improve performance. Research focuses on reducing the cost of systems that manage the temperature of battery systems, increasing batteries' tolerance to abusive conditions, developing computer-aided engineering tools to design batteries, and improving sensors to monitor battery systems.
Through its work with industry, VTO has supported a number of breakthroughs in battery technology. Research VTO supported helped reduce production costs of automotive lithium-ion batteries by more than 50% since 2008, bringing the cost down from $600/kwh to less than $400/kwh. Battery cell specific capacity has also increased from 150 Wh/L in 2008 to more than 350 Wh/L while achieving more than 5,000 PHEV cycles and 1,000 EV cycles.
VTO's long-time commitment towards improving Li-ion batteries has already yielded significant results. Hybrid electric vehicles from BMW and Mercedes are using Li-ion technology developed under VTO-supported projects with Johnson Controls-Saft. VTO's past research in this area also helped develop the lithium-ion battery technology used in the Chevrolet Volt, the first commercially available PHEV. This technology is now being used in a variety of hybrid and plug-in electric vehicles coming on the market now and in the next few years, including the Ford Focus EV.