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| Nanophosphate Engine Start Battery (12V): Click to enlarge. |
A123 Systems is targeting the emerging stop-start/microhybrid market with a 12V Li-ion battery solution based on its automotive class lithium ion AMP20 20 Ah prismatic pouch cells. The system comes equipped with battery management electronics for cell balancing and protection.
Compared to lead-acid AGM batteries used in such applications, the Li-ion batteries offer better charge acceptance, ultimately resulting in lower alternator loads on the engine and better fuel economy; lighter weight (about 60% less than comparable lead-acid batteries); and longer life, according to Jeff Kessen, A123’s VP of Automotive Marketing and Communication.
In addition to the two posts on the 12V package, the battery has a communication connector to the vehicle controller.
Our approach is a little bit different than the Gaia package that Porsche is using [earlier post]. In that application, they are constrained on the cold side…so for a mainline car manufacturer, that’s not really an option. Our package is still in the 60 Ah to 80 Ah range, depending on the specific design, because we have to have to cold starts. We are really going for direct replacement, not asking [OE’s] to compromise on the performance.
—Jeff Kessen
A123 has had a version of the system in a demanding bus application for almost three years, and is tracking to about 6 years of life, Kessen says. By contrast, AGM batteries in that type of application are lasting 18 months to two years. The additional lifetime of 2.5 to 3x will help offset the higher cost of the Li-ion solution, Kessen says.
The Amp20 cells were designed for plug-in hybrid and electric vehicle applications, and offers a power density of more than 2,400 W/kg and 4,500. Nominal voltage is 3.3V.
A123 Systems currently has production agreements with two automotive OEs. The first, a more conventional SLI application rather than a microhybrid, was what initially pulled A123 into the 12V space, Kessen said. Since then, the company has entered a production contract with a major yet-to-be-named OE on a stop-start system. A123 Systems says that it is also in development with four other vehicle manufacturers.