Toyota is secretly developing an auto powered by solar cells mounted on the vehicle’s roof, according to a related report says recently. The report said the automaker hopes the vehicle will eventually be totally powered by the solar cells—but that would take many years. Prior to that time, energy from the sun could provide only some of the power for the vehicle’s batteries and other electric accessories.

In fact, Toyota will debut a small battery-electric concept auto at the 2009 North American International Auto show. “This is a pure electric vehicle,” said Toyota spokeswoman Jana Hartline. “It’s a concept we are bringing to the show basically to confirm our interest in electric vehicles.”

Toyota’s plans to harness power from the sun could get a boost when Panasonic Corp., Toyota's partner in advanced battery production, completes its planned takeover of Sanyo Electric Co., a leader in solar technology. Toyota uses solar panels at its Tsutsumi plant in central Japan to produce some of its own electricity—roughly enough to power 500 homes.