The four-door luxury saloon employs a low-temperature proton exchange membrane (LT PEM) fuel cell stack and carbonfibre hydrogen tanks together with a plug-in lithium-ion battery and a pair of electric motors to achieve an overall zero-emission range of up to 311 miles.
Mounted up front in the space usually taken up by the A7’s more traditional combustion engines, the fuel cell employed by the A7 h-tron comprises over 300 cells, each of which is a polymer membrane separated by a platinum-based catalyst. It operates in a voltage range between 230 and 360 volts.
The fuel stack is supported by a plug-in 8.8kW/h lithium-ion battery mounted within the floor of the boot. It boasts a recharge time of two hours on a regular 240-volt mains and also stores recuperated kinetic energy, helping to extend the overall range up a claimed 31 miles. Refilling the hydrogen supply, meanwhile, takes two minutes.