Mitsubishi Chooses Toshiba SCiB Battery for i-MiEVBy Scott Doggett June 22, 2011
Toshiba Corp. today announced that its SCiB lithium-titanate oxide battery pack has been selected by Mitsubishi Motors Corp. to power two battery-electric vehicles (BEVs), the i-MiEV (to be known as Mitsubishi i in North America when it goes on sale here early next year) and its taxi variant, the Minicab-MiEV. Despite reports by various blogs that the decision means Mitsubishi Motors has abandoned the BEV battery pack it has developed with joint-venture partners GS Yuasa Corp. and Mitsubishi Corp., a Mitsubishi Motors spokesman told AutoObserver that the automaker intends to employ both battery packs in its BEVs "at least for the near term."
"No one has made a decision to discontinue" use or development of the lithium-ion batteries produced by the joint venture, Maurice Durand said in an interview today. The joint venture was formed in 2008 to develop and manufacture large-capacity, high-performance lithium-ion batteries for use in BEVs and plug-in hybrids. Mitsubishi Motors decided to use Toshiba's SCiB (Super Charge Ion Battery) packs to supplement those of the joint venture to ensure the automaker's ability to meet anticipated demand for the BEVs it brings to market during the next few years.
Mitsubishi's decision to use Toshiba's SCiB packs can be seen as another endorsement of the lithium-titanate battery. Altairnano produces lithium-titanate batteries under the Nanosafe line for numerous planned BEVs, and SCiB batteries are used in Schwinn's Tailwind electric bike. The SCiB employs lithium-titanate oxide in the anode, which Toshiba claims offers a high level of operating safety, a long life and rapid charging. The use of lithium-titanate oxide also significantly reduces the possibility of a puncture in the separator between the anode and cathode, minimizing the risk of them coming into contact and short circuiting, Toshiba says. The company also claims the lithium-titanate oxide maintains battery performance levels in severe operating conditions, including very low temperatures.
More Powerful, Faster Charge Time
Toshiba says the SCiB pushes the life of the lithium-ion battery to a new level by supporting two-and-a-half times more charge/discharge cycles than a typical lithium-ion battery. Recharging is also notably better. Charged with the highest current available with the so-called CHAdeMO charging technology, which is widely seen as the emerging standard for fast charging electric vehicles, an SCiB reaches about 80 percent of full capacity in some 15 minutes, about 50 percent in 10 minutes and about 25 percent in 5 minutes. All times are for a battery with a capacity 10 kilowatt-hours. A Nissan Leaf, for example, uses a 24-kWh battery and can travel approximately 100 miles between charges. By comparison, the SCiB requires half the charge time of a typical lithium-ion battery charged under the same conditions. The SCiB also generates little heat while recharging, eliminating the need for power to cool the battery module.
Most important of all for real-world application, Toshiba claims, the SCiB delivers high level performance. The SCiB offers a higher effective capacity than a typical lithium-ion battery, in that more of the stored charge can be used safely before recharging the battery. This, combined with highly efficient regenerative charging during braking or coasting downhill, allows the SCiB to deliver a claimed 70 percent more driving distance per level of charge of a typical lithium-ion battery. This will allow for installation of smaller battery modules in vehicles and contribute to lower electric-vehicle prices, Toshiba says. The SCiB also offers high level performance in a wide range of temperatures, and continues to support rapid charging and excellent power output at temperatures as low as -30 degrees Celsius (-22 degrees Fahrenheit).
The SCiB for Mitsubishi's BEVs will be manufactured at Toshiba's Kashiwazaki Operations in Niigata prefecture, northwest Japan. It is a new facility dedicated to production of the SCiB, which came on line in February of this year. Toshiba said it will seek to establish a plant operating structure able to respond quickly to market growth as the basis for expanding the SCiB business for electric vehicles, including hybrid and plug-in hybrid EVs.