This might help. The Airbus website for the project:
Airbus Group - E-Fan electric aircraft
BTW, in automotive terms the four seater would be called a series hybrid because it derives fan power only from the batteries, while the engine drives a generator for recharging inflight.
An exiting aspect of this is the effort to deploy superconductive cabling from a Russian company.
More on suppliers here:
E-Fan Electric Aircraft - Aerospace Technology
The batteries are supplied by CleanCarb, which produces the KOKAM brand. The company is German with technological roots from several European academics. An interesting aspect of this, not mentioned in the Arbus information, is that CleanCarb is deeply involved with ultracapacitor research also.
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An acquaintance of mine tells me that the hope is to integrate SOA cells with superconductors, soa ducted fans and ultracapacitors to reduce the wasted energy and weight of cabling/power transmission (can reach >6% of total weight in large traditional commercial aircraft) while using sao avionics and other systems to reduce weight and improve performance.
A more traditional approach has been used by Embraer, which has a flying demonstrator now:
First flight | Revista Pesquisa FAPESP
This one was developed from the Sora, a Brazilian entry in the Light Sport Aircraft category. It uses currently available technology and suppliers, so does not test the technological boundaries as does the Airbus project, but it does prove that the concept works in a reasonably practical way.
The most interesting part of all this beyond the future possibilities is the question of the impact these might have on flight training. if a pilot has initial training on the Airbus, for example, while the pilot have a multi-engine rating since there are two motors and fans? of course it has no engines: does that mean it will be a new category? Will a private pilot earning that license in an Airbus be considered qualifies to fly an ICE equivalent? The entire light aircraft licensing process in the US (Part 23 of the Federal Aviation Regulations) is now being rewritten. These developments will give the regulators headaches just as did the B787 before it. One hopes Airbus has learned from the Boeing debacle.
FWIW, the NTSB hearings on Li-ion in transportation included testimony from Tesla engineers who described the Tesla approach to quality control, well in excess to any other in use at the time including that of the US Navy in nuclear submarines.