You could say that this battery-powered R8 lookalike cost €36 million (R404 million) and took three years to build - or you could say that is the tangible result of a three-year collaborative research project by Audi, Bosch and several faculties at Aachen University.
Either way, the aim was to develop a scalable systems architecture for electric, a flexible technology platform, including a plug-in hybrid drive, suitable for anything from a sports car to a sedan to a city car.
The project leaders broke the huge body of research required down to a dozen work packages, from the energy storage system to the control concept to dynamic stability control.
In the initial phases, the groups worked mostly with computer simulations, then the sub-modules and finally, when each module had been tested and proven, a drivable car, the F12, which represents the “e Sport” model within the modular system platform.
HIGH-VOLTAGE BATTERIES
One of the key focuses of the project was the high-voltage battery. The final version in the F12 has two separate blocks, each made up of 2000 lithium-ion cells, with a combined capacity of more than 38 kWh.
Beveled walls allow the cells to shift relative to each other for additional safety in a crash, while cast-aluminium sections in the battery mountings absorb most of the crash energy.
The research car has three electric motors, each separately controlled. In slow driving around town, only the synchronous motor on the front axle is active but, at higher speeds, two asynchronous motors on the rear axle chime in to create a fully-electric quattro with (a mere) 150kW and 550Nm on tap.
DIFFERENT VOLTAGES
What makes the two batteries special is that they operate at different voltages - 144V on one side and 216V on the other, regulated by a DC/DC converter. Under part load, the voltage is about 200V to maximize efficiency but with increasing power demand and speed this increases to as much as 440V.
The driver controls the basic drive functions - Park, Reverse, Neutral and Drive - by pressing buttons on the centre tunnel; everything else is controlled from a removable tablet in the centre stack.
SPIN-OFF RESEARCH
From the start, everybody used digital cameras to document each design step, and post the results on a server accessible to everybody in the group.
And it's not over yet. Sure, the €36 million car is finished and (if anybody is brave enough) driveable, but the first spin-off research projects have already started, focusing on particular areas, such as thermal management and the carbon-fibre housing for the rear battery - which shows good prospects for later production use.