DETROIT – 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 says it likely will be two years before the first production HEV using Li-ion batteries hits the showroom.

Speaking at the Convergence 2006 Transportation Electronics Conference here, 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 commensurately more expensive, despite the fact developers and suppliers have markedly reduced their energy density (and thus reduced the amount of nickel needed for a given amount of energy storage).

Li-ion batteries for HEVs are “on the horizon,” Hermance says, adding, “There is tons of money being spent on battery development.”

Hermance says Li-ion development is crucial 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.

The PHEV technology theoretically would enable greater fuel-economy benefits because the vehicle’s engine power would not have to be used as often to charge the batteries, but also because purpose-built PHEVs – with their more-powerful and higher-capacity batteries – would be able to run in a wider range of driving conditions solely on battery power.

When asked by a conference attendee if PHEVs will be on the road by 2009, Hermance says an OEM-produced PHEV is unlikely to be available 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.

Meanwhile, the rated fuel economy of HEVs and conventionally powered vehicles is due for a disappointing downgrade in 2008.

Hermance says that’s when the fallout will hit from new Environmental Protection Agency test procedures that result in the familiar city and highway mileage ratings on new-vehicle window stickers. Hermance says the EPA is expected to finalize the new tests by the end of the year, and all ’08 models sold in the U.S. will have to show fuel economy ratings derived from the new procedures.

Hermance says it is unfortunate the U.S. still expresses fuel economy on a miles-per-gallon basis, rather than the liters-per-100 km (62 miles) measure used in Europe.

“The Europeans got it right,” he says, noting that fuel used over a fixed distance is the better way to express fuel efficiency.

bvisnic@wardsauto.com