Technology to Improve the Performance of Lithium-Ion Cells at Low Temperatures

Hybrid electric vehicles (HEVs), plug-in hybrid-electric vehicles (PHEVs), and electric vehicles (EVs) are key technologies for reducing the nation¿s dependence on imported petroleum, reducing greenhouse-gas emissions and air pollution, and conserving petrochemical feedstocks. Because lithium-ion batteries have a higher energy density relative to the presently-used nickel-metal hydride batteries, lithium-ion batteries have the potential to extend the range of these vehicles, while also reducing battery mass and size. In particular, lithium iron phosphate ¿ which offers much higher safety, higher abuse tolerance, longer cycle life, and lower cost ¿ presents an opportunity to accelerate the introduction of lithium-ion batteries for automotive applications. However, the low-temperature performance of present lithium iron phosphate materials does not meet the targets of the U.S. Advanced Battery Consortium. This project will conduct a study to improve the low-temperature performance of lithium iron phosphate. Phase I targeted the activation energy for transport processes, as a potential pathway for improving the low-temperature performance of lithium iron phosphate. Phase II will continue the strategies identified in Phase I and develop a material that meets the requirements for automotive batteries at low temperature. Commercial Applications and other Benefits as described by the awardee: Because of its great advantages in cost and safety relative to presently-used, metal-oxide cathode materials, an improved lithium-iron-phosphate cathode would accelerate the introduction of lithium-ion batteries for hybrid electric vehicle applications. In a field currently dominated by a few Asia-based companies, this technology may allow the U.S. to reclaim large parts of the lithium-ion battery market