A123Systems Begins Taking Consumer Orders for its Hymotion™ L5 Plug-in Conversion Modules

Watertown, Mass. – April 28, 2008 – A123Systems, developer and producer of Nanophosphate™ lithium ion batteries, today announced the launch of its Hymotion product line’s new Web site, www.hymotion.com, designed to provide information and take orders from individuals interested in purchasing the L5 Plug-in Conversion Module (PCM) for the Toyota Prius. A123Systems also continues to sell Hymotion Plug-in Conversion Modules to fleet and government buyers, with more than 50 vehicles currently on the road in corporate and government demonstration programs.

A123Systems’ Hymotion product line is the only fully tested PCM that meets or exceeds federal requirements for crash-worthiness and emissions. Based on independent testing performed at Argonne National Labs as well as Idaho National Labs, the L5 PCM will enable a Toyota Prius to obtain fuel economies of more than 100 miles per gallon.

A123Systems is in the process of developing and certifying a nationwide dealer network for the Hymotion product line, beginning with Hymotion dealerships in Seattle, San Francisco, Los Angeles, Minneapolis, Boston and Washington, D.C. In an important step for broad acceptance, A123 has been working with the California Air Resources Board (CARB) and has outlined a path for conditional approval from CARB to sell up to 500 conversion modules in the state of California to begin its consumer launch.

“This long-anticipated announcement is celebrated not only by us as the culmination of years of hard work, but by many who are eager to dramatically lower emissions and free themselves from dependence on petroleum,” said Dave Vieau, CEO of A123Systems. “Today, we begin a process that could conceivably change the environmental, economic and political implications of driving a car for the better.”

According to the Electric Power Research Institute (EPRI), half of the cars in the U.S. are driven just 25 miles a day or less. With an average electrically assisted driving range of 30-40 miles, a Toyota Prius equipped with a Hymotion L5 module charged overnight via a standard 120 volt outlet will, for most drivers, significantly reduce the amount of petroleum consumed and CO2 emitted. An L5 charged from the average national blend of electricity results in a 50 percent or greater reduction in overall “well-to-wheel” CO2 emissions compared to a traditional gas-powered vehicle. The L5 module is also environmentally friendly and fully recyclable, containing no heavy metals or toxic chemicals.

Plug-in Conversion Modules will be available for owners of Toyota Priuses, model year 2004 to 2008. At an installed cost of $9995 plus shipping, buyers can choose a certified Hymotion dealer for conversion of their hybrid vehicles. Installations for consumers are expected to begin in July,2008.

About A123Systems

A123Systems is one of the world’s leading suppliers of high-power lithium ion batteries. The company’s patent pending Nanophosphate™ technology enables its batteries to deliver a previously unavailable combination of power, safety and life. Applicable to a wide range of industries, A123Systems’ products remove many traditional technology constraints to provide OEMs expanded flexibility in system design. With world-class expertise and management, global manufacturing operations and one of the largest automotive lithium ion R&D teams, A123Systems’ and its Automotive Class Lithium Ion™ products are helping to accelerate platform electrification. Founded in 2001 and headquartered in Massachusetts, A123Systems’ proprietary nanoscale electrode technology is built on initial developments from the Massachusetts Institute of Technology. A123Systems' Advanced Research & Government Solutions Division in Ann Arbor, Michigan is nationally recognized for new materials development and cutting-edge research. For additional information please visit www.a123systems.com.

About our Hymotion™ Product Line

A123Systems’ Hymotion product line bridges the current HEV-PHEV gap by enabling thousands of existing hybrids on the road to reach their full green potential through conversion to plug-in hybrids. Our Hymotion product line was developed by automotive industry veterans who set out to design advanced green transportation systems that improve upon existing vehicles and can be used by consumers today.