Hitachi has just announced a new generation of its lithium ion batteries with significantly more specific power than current cells. The new cells have 70 percent more power than current cells and 50 percent more than the next-generation cells that go into production in 2010. The new cells are claimed to produce 4,500 W/kg along with 20 percent longer life than existing units. Hitachi expects to start producing the new cells sometime in the middle of the next decade.
In the meantime, Hitachi will be supplying lithium ion batteries to General Motors
in 2010 for the next generation of the automaker's mild hybrid
system. The nickel metal hydride battery pack in the current mild hybrids will be replaced by a smaller lighter lithium unit along with a significantly more powerful motor/generator.
[Source: Green Car Congress