Toyota unveils plug-in hybrid, to test on roads

By Chang-Ran Kim, Asia auto correspondent

TOKYO (Reuters) - Toyota Motor Corp. (7203.T: Quote, Profile, Research) unveiled a "plug-in" hybrid car based on its popular Prius model on Wednesday, saying it would test the fuel-saving vehicle on public roads -- a first for the industry.

But the world's biggest automaker said the car, called the Toyota Plug-in HV, was not fit for commercialization since it uses low-energy nickel-metal hydride batteries instead of lithium-ion batteries believed to be a better fit for rechargeable plug-in cars.

Unlike earlier gasoline-electric hybrids, which run on a parallel system twinning battery power and a combustion engine, plug-in cars are designed to enable short trips powered entirely by the electric motor, using a battery that can be charged through an electric socket at home.

Many environmental advocates see them as the best available technology to reduce gasoline consumption and global-warming greenhouse gas emissions, but engineers say battery technology is still insufficient to store enough energy for long-distance travel.

"It's difficult to say when plug-in hybrids could be commercialized, since it would depend largely on advances in battery technology," said Executive Vice President Masatami Takimoto, in charge of Toyota's powertrain technology, told a news conference.

The Toyota Plug-in HV, which is due to be tested also in the United States and Europe, has a cruising range of just 13 km (8 miles) on one charge, even with its trunkful of batteries.

Detroit's General Motors Corp. (GM.N: Quote, Profile, Research) and Ford Motor Co. (F.N: Quote, Profile, Research) are also working on plug-in hybrids, with cooperation from battery makers such as Germany's Continental AG (CONG.DE: Quote, Profile, Research) and Korea's LG Chem (051910.KS: Quote, Profile, Research)

GM in January showed a concept version of the plug-in Chevrolet Volt that would be powered by a lithium-ion battery. It has set 2010 as a target for production.