The problem has been a tendency of some lithium chemistries to heat up and burn. The Sandia National Laboratory has been using its expertise to test the various types to ascertain which will perform to standards required for use in plug-in vehicles. The Department of Energy is funding the FreedomCAR program to put the batteries, supplied by manufacturers, through the paces. Nails are driven through the batteries, and they are overcharged and subjected to extreme heat.
As reported at Azonano.com, the results have been extremely positive. "Lithium-ion batteries, generally found in laptop computers and power tools, have greatly improved over the past few years," says Peter Roth, lead researcher for Sandia's FreedomCAR battery efforts. "In fact, they have improved so much that we expect to see them in hybrids later this year and possibly even in short-range plug-in hybrids within two years."
With Tesla Motors poised to begin delivering its fully certified lithium-powered Roadster by the dozens within a month or so, it looks like Sandia's expectations are to be exceeded.