The lithium-ion charge is on

Multiple engineering trade-offs define the capabilities and limitations of the latest lithium-ion batteries for next-generation hybrid, plug-in, and pure-electric vehicles.

Even though the internal-combustion engine will for the foreseeable future remain the principal powerplant for car and truck propulsion, in the long term electric-drive technology is the key to environmentally sustainable road transportation. Electric power means batteries, of course, and as anyone who uses a mobile phone or laptop computer knows, current electrochemical energy-storage systems often leave much to be desired in terms of energy density and capacity. The limitations of large-format, high-power batteries for vehicles are even more severe.

Such is the case because functional batteries are “boxes of technical trade-offs and compromises,” as one noted battery expert puts it. Maximization of nearly any important performance characteristic or feature nearly always results in the diminution of another. Right now, scientists and engineers are wrestling with the many interrelated technical factors that determine battery performance to produce “Goldilocks” systems with properties optimized to be “just right” for powering the hybrid-electric (HEV), plug-in hybrid electric (PHEV) and, eventually, pure-electric (EV) vehicles. The quest for truly effective energy storage for electric-drive technology, though promising, will have to continue for many years to come.