Toyota Studies Magnesium Battery as Lithium Alternate

Toyota Motor Corp., the world’s largest seller of hybrid autos, said it’s developing a magnesium battery that holds twice the energy of lithium-ion cells as automakers seeks better ways to power electric cars.

The company’s technical center in Ann Arbor, Michigan, is working on the magnesium-sulfur battery, complementing development of other future electric-power chemistries at Toyota labs in Japan, Jeffrey Makarewicz, the engineer managing the U.S. project, said in an interview at the North American International Auto Show in Detroit.

“Going from nickel-metal hydride to lithium ion, you essentially double the energy capacity,” he said. “Lithium ion theoretically, under ideal conditions, has a capacity of about 2,000 w/kg. That’s still not enough to really make a very competitive battery that’s necessary for future plug-in, electric and hybrid-electric vehicles.”

Vehicles with magnesium batteries or alternative materials may be ready by about 2020, Makarewicz said. Toyota is working on such technologies as Nissan Motor Co. and General Motors Co. in the past month have released rechargeable models with lithium-ion packs that let drivers go extended distances on battery power alone.

Nissan wants its Leaf to be the world’s top-selling all- electric car, aiming for annual global sales of at least 500,000 battery-powered cars including Leaf and models from affiliate Renault SA within the next few years.

Toyota expects “much more modest” U.S. demand for battery-only vehicles during that period because of power-pack limitations, Bob Carter, the Toyota City, Japan-based company’s U.S. group vice president, said in an interview today in Detroit.

The automaker’s U.S. unit, based in Torrance, California, is also looking at aluminum and calcium as potential battery materials, Makarewicz said. In Japan, company engineers are researching “lithium air and metal air” batteries, he said, without elaborating.

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