An anonymous reader writes "Tesla finally delivered its first production model of the all-electric Roadster this month. Coinciding with that, researchers from the big automakers and their outsourced startup labs are hitting stride in the development of cheap, high-powered lithium-ion batteries. These may actually end up in our garages. Toyota, in fact, says it's got enough of the chemistry down to roll out a test fleet for the plug-in Prius before the end of 2009. It's mass production of battery tech that's the holdup — which might mean Mercedes' electric hybrids beat the Prius to market en masse by 2010 or 2011."