Improvements over today's familiar nickel-metal-hydride batteries will enable new performance and economy gains for hybrid-electric vehicles, but Toyota Motor Corp.'s HEV guru cautions the new batteries are not imminent.

Dave Hermance, executive engineer-Advanced Technology Vehicles, Toyota Technical Center USA Inc., says lithium-ion batteries, much like those used in many of today's consumer-electronic devices, will produce new possibilities for HEV performance, but it likely will be two years before the first production HEV using Li-ion batteries hits the showroom.

Speaking at Convergence 2006, Hermance says the auto and battery industries are anxious to speed Li-ion development for HEVs not just for their expected performance boost, but also because the price of nickel has tripled in the last five years.

That makes today's NiMH batteries more expensive, despite the fact developers and suppliers have markedly enhanced their energy density (and thus reduced the amount of nickel needed for energy storage). Li-ion batteries for HEVs are “on the horizon,” Hermance says.

Li-ion development is crucial, he says, before there can be reasonable expectation for so-called “plug-in” HEVs, which allow consumers to plug into a standard electrical outlet to charge a vehicle's batteries.

When asked if PHEVs will be on the road by 2009, Hermance says an OEM-produced PHEV is unlikely by then because the batteries will not be ready. PHEVs “have to make the transition to Li-ion (batteries) to make it even remotely considerable,” Hermance says.