When the 2112 Ford Focus Electric debuts in late 2011, it and the Chevrolet Volt will have a common feature in addition to their LG Chem lithium polymer cells. Ford confirms that the Focus EV will employ a liquid-cooled battery pack with automatic thermal management, just like the Chevy.
Ford opted for active thermal management solution in order to help maximize the Focus EV's battery performance and lifespan. By protecting the battery from overheating, the system can help prevent the development of cracks in the electrodes. Those imperfections eventually reduce the pack's ability to hold a charge. Conversely, warming the cells when cold will improve the battery pack's winter performance. When the car is plugged in, the thermal management system will use grid power to precondition the battery before charging actually starts.
So far, Nissan and Mitsubishi are the only major EV manufacturers that are sticking with passive air cooling for plug-in vehicles. Nissan has committed to an eight-year warranty, but it remains unclear how well the battery will hold up over regular use in differing climates.