"What people have tended to do so far is make the sill strong and stiff, and then just put all the battery cells in the middle," McNamara says. "What we're saying is don't make the sill quite as strong, allow some of the load to come into the cells, and allow each module to take some of the stress. And by bolting all those modules down, we get a lot of torsional and bending stiffness through the platform. We're not having to handle all the stiffness through the sill."

This strategy also allows the FW-EXV to cleverly use the platform sills as cooling elements for the battery pack. Air enters two narrow tubes at the front of the vehicle and is channeled through the sills, the inside of which are filled with cooling fins, exiting at a low pressure area under the floor at the rear of the platform that helps draw the air through the system. The system is augmented by a refrigerated cold plate underneath the batteries that helps keep them under 40 degrees Celsius.

The benefit of the system, says McNamara, is it eliminates the need for conventional cooling radiators at the front of the car, and the need to pipe coolant around the battery pack, therefore reducing weight and complexity, and improving the vehicle's drag co-efficient.

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As displayed, the FW-EXV platform could underpin a sedan the size of a BMW 3 Series. McNamara says Williams Advanced Engineering has also designed a version for a sporty, low-slung coup that features reduce height battery modules to get the seats lower, with additional batteries located in a tunnel running down the center of the platform to increase range and performance.

Williams Advanced Engineering managing director Craig Wilson freely admits most mainstream automakers have viable BEV platforms of their own already under development. He says the FW-EXV, which uses off-the-shelf e-motors and electronic control systems, is designed for use by low-volume performance vehicle manufacturers.