Airbus is flying toward the future of aviation with its innovative electric and hybrid aircraft research. Join the company on this journey: this section provides regular updates for an in-depth look at the disruptive technologies and concepts that are supporting its ambitious e-aircraft goals.
Fuel Cells: a groundbreaking idea for electric propulsion
Imagine a short-range commercial aircraft that is powered by hydrogen fuel, and emits no harmful gases into the Earth’s atmosphere. That’s the potential of fuel cells.
This exciting concept for electric propulsion is one of the many promising ideas that could play a huge role in helping the aviation industry reach its ambitious environmental targets.
“Fuel cells are far out, but maybe not too far away,” explained Christian Wolff, Head of the Electrochemical Systems Team – as part of the Airbus’s research and technology network, which is leading the E-Fan programme and the company’s electric-airplane initiatives.
Fuel cells: How they work
For aviation applications, hydrogen/air fuel cells could produce electric power in the 15-MW range that is necessary for commercial aircraft jet engines.
In these low temperature proton exchange membrane (PEM) fuel cells, hydrogen fuel is supplied to the fuel cell’s anode. In the anode, an electro-chemical reaction separates the hydrogen into negatively-charged electrons and positively-charged protons.
The electrons create an electrical current that is distributed through a circuit, while the protons travel through a substance called a proton exchange membrane (PEM), which blocks all electrons.
The future vision: Bringing fuel cells to aviation
Airbus researchers are exploring the application of fuel cells integrated directly into the aircraft electric engine.
For this configuration fuel cells are arranged as multiple “stacks” directly alongside an electric engine. They are positioned around the inner fixed structure that encases the engine’s fan blades, along with magnets on the rotor and coils on the stator.
The revolutionary idea is that the fuel cells’ direct current output is transferred directly to the motor coils thus driving the fan blades directly without heavy wiring, bus bars, converters, or batteries.
Fuel cells generate electrical current by converting chemical energy to electrical energy, and – unlike batteries, which have a fixed supply of energy – can continuously provide energy as long as fuel is supplied. The only by-products of the chemical reaction are water and heat.
On the other side of the cell’s PEM is its cathode, where oxygen (air) is supplied to the system. The protons – arriving through the PEM – and electrons, returning from the electrical circuit, bond with the oxygen to form the cell’s two waste products: water (H2O) and heat. In aircraft, the fuel cells would be cooled by airflow through the electric engines.
“Exploring fuel cells deeper is important as we study technologies and concepts that could bring about a new generation of electric aircraft. A breakthrough in fuels cells for aviation could be game-changer!”
“Fuel cells are part of the wide range of long-term concepts under consideration by the Group for electric and hybrid aircraft,” Wolff said. “We know the basic elements exist and are exploring how to optimize them for a new-generation of more electric aircraft.”
A platform for electric aircraft development
As a demonstrator aircraft, the all-electric E-Fan is serving as a platform for Airbus Innovations and its partners to evaluate breakthrough technologies for electric and hybrid aircraft. The E-Fan team has continuously worked to enhance this innovative electric plane since its introduction, providing significant performance improvements and also gaining expertise that potentially could be applied to Airbus’s other products.
The E-Fan’s two electric motors deliver a combined power of 60 kW, each driving an aft-mounted ducted, variable pitch fan. Electrical energy for these motors comes from the aircraft’s battery system, for which capacity has been increased by 60 percent since its first flight in 2014.
In its original configuration, E-Fan utilized a series of lithium-polymer batteries located inside the wings, where fuel tanks would be on a traditional aircraft. The E-Fan team has since changed to a more powerful lithium-ion battery system, which was a key upgrade that enabled the technology demonstrator aircraft’s historic flight across the English Channel in July 2015. Comprising 2,982 cells with a capacity of 2.8 amperes per hour each, the lithium-ion battery system retains the same location as the previous lithium-polymer cells with E-Fan’s wings.
Just as a traditional aircraft need to be fueled after flight, E-Fan is ‘topped off’ through the recharging of its batteries. A mobile cart that plugs into any industrial-type electrical outlet is used for the recharging process, thereby managing the most efficient power-up cycle.
An optimised electrical energy management system proven on E-Fan – called E-Fadec – automatically handles all electrical features, will be evolved for its use on the production E-Fan versions. This system reduces the workload, increasing safety by enabling pilots to focus their attention on flying the aircraft.
Another innovation originally applied to E-Fan is its landing gear, which consists of two wheels positioned fore and aft under the fuselage, plus two small wheels under the wings. In E-Fan’s initial configuration, the aft main wheel was driven by a six-kilowatt electric motor, providing power for taxiing and acceleration up to 60 km/h during takeoff, reducing overall electrical power consumption in day-to-day operation. As part of the updates applied to E-Fan to help extend flight duration for its historic cross-Channel flight, this motor was removed.
The “buzz” on Airbus’ e-aircraft development
Stay up-to-date with tutorials on the advanced technologies and concepts that are making electric aviation a reality for the Airbus: