One of the industry’s top contenders in the race to manufacture more powerful next-generation batteries for the auto industry has integrated a lithium ion battery into a Toyota Prius. EnerDel, based in Indianapolis, Ind., exhibited the research vehicle with the new battery pack at the International Electric Vehicle Symposium (EVS-23) in Anaheim, California.

EnerDel’s demonstration vehicle is not a plug-in hybrid and does not replace the Prius’s existing control systems. Instead, it demonstrates how lithium ion batteries can double the amount of electric energy storage while taking exactly the same space as the Prius’s current hybrid batteries.

"We have made a major stride toward providing the power, safety, and affordability that the market has been waiting for," commented Ulrik Grape, Ener1 Executive Vice President for Global Sales and CEO of EnerDel. "We believe that ours is the safest high-power lithium ion battery available for hybrid electric vehicles."

The transition to lithium ion from the current nickel metal hydride battery technology found in today’s hybrids could allow gas-electric vehicles to stay in all-electric mode for greater distances—substantially increasing the fuel economy. The exact benefit of EnerDel’s Prius—in terms of mpg—will not be known until EnerDel releases third party testing in early 2008.

One More Step Toward Lithium—With or Without Plug

A number of battery companies, utilities, advocacy organizations and individuals have used lithium ion batteries to convert Priuses into plug-in hybrids. In fact, Toyota exhibited its own plug-in Prius research vehicle at EVS23. As with the independent plug-in conversions, Toyota’s plug-in Prius require space beyond the compartment found behind the back seat which houses the conventional Prius’s battery pack. The conversions usually usurp the space provided for the spare tire. Toyota opted for nickel metal hydride for its plug-in prototype to produce a vehicle that can travel further in all-electric range than conventional hybrids (approximately seven miles), but not as far as if lithium batteries were used. The company has not announced any plans to bring a plug-in Prius to market.

Many industry observers had expected the next generation plug-less Prius, due in 2009, to use lithium batteries. But Toyota announced in May 2007 that the company’s flagship hybrid would continue using nickel metal hydride batteries. The decision reflects Toyota’s strategy to protect its lead in the hybrid market, rather than taking chances with lithium batteries that carry greater cost and safety concerns.

EnerDel’s lithium-powered Prius is one more step in what many see as a likely transition of auto batteries to lithium technology—first in conventional hybrids and then in plug-in hybrids and electric vehicles.