Toyota Dumps Lithium-Ion Batteries for Prius

Bloomberg has a nice little scoop here. After three years of secretly testing lithium-ion packs, Toyota has decided to stick with nickel-metal hydride batteries for the Prius. Just to explain the difference between the two types of battery. NiMH can’t store as much energy as Li-Ion, and Li-Ion is lighter, making it, according to many, the battery of the future for the auto industry.

But for now, Toyota is sticking with proven NiMH tech. Why? Cost is evidently the main factor. Li-Ion is more expensive than NiMH. But Toyota and its main battery partner, Panasonic, seem to have been struggling with advanced Li-Ion designs for a while. Back in 2007, Toyota indicated that new Priuses would continue to use NiMH, because the Li-Pack it was working with were raising safety concerns. They were catching on fire, for example. Not something you want in a vehicle that’s also carrying around a dozen gallons of highly flammable fuel.

Elsewhere, Li-Ion is moving forward briskly in automotive applications. Tesla, for example, has been successful at getting 200-plus-mile range out of an elaborate, 6,000-plus cell Li-Ion pack, of not at reducing its cost or weight. And General Motors (MTLQQ) is working with Korean supplier LG Chem to get Li-Ion cells for the forthcoming Chevy Volt, an extended-range electric car that’s supposed to be priced between $30,000-$40,000. (GM will be assembling the battery packs itself.)

It’s fruitless to puzzle excessively over why Toyota is getting off the industry-wide Li-Ion bandwagon. But it’s possible that there’s an element of technological self-preservation at play. Toyota has sold a lot of NiMH Priuses. The company owns the hybrid mindshare. Delaying Li-Ion could be a strategic decision, to avoid lending credence to a technology that would, in all-electric cars, end up going head-to-head for future Prius customers.