Greentech Media

Before A123Systems' launch in 2001, it was nearly impossible to get anyone to consider a battery company a "hot" investment. But A123 has done just that, putting batteries on par with wind turbines and solar panels in the consciousness of not only the greentech-focused investor, but the tech-savvy public at large.

A123Systems begins with a proprietary doped-nanophosphate technology, licensed from MIT, that greatly improves its lithium-ion battery's power density while reducing its risk of overheating or explosion. With this technology at its disposal, one might have expected A123 to immediately swing for the fences, building the next laptop or electric car battery. Yet it chose a pragmatic path that is clearly paying dividends. First stop: building-contractor-grade power tools, which are greatly enhanced if they can go cordless, but with typical batteries tend to go dead halfway through a carpenter's day. A123 scored a contract with Black & Decker for its 36-volt DeWalt power tools, proving the technology and building revenues and respect, while prepping the technology for the automotive market.

Right now, A123 is beyond hot. It has demonstrated its technology for plug-in hybrid electric vehicles, been awarded $15 million from the United States Advanced Battery Consortium and inked deals with GM and Saturn, BAE Systems and Cobasys (despite being embattled with a patent-infringement lawsuit). To make sure it is well-positioned for the coming plug-in hybrid market, the company recently acquired Hymotion. A123's chairman, Desh Deshpande, is legendary in Boston tech circles and has an uncanny ability to attract talent and capital to a startup - witness A123's recent $40 million round. Other battery companies in the greentech market warrant attention, but today A123 so completely owns the mindshare around advanced storage, and a substantial market lead, that we just had to award it our top spot on this inaugural list.