ZeroAvia high temperature fuel cell testing shows potential for hydrogen-electric propulsion

ZeroAvia claims it has achieved record-break­ing per­for­mance in test­ing its 20kW high tem­per­a­ture pro­ton exchange mem­brane (HTPEM) stack pow­er mod­ule, ear­ly test­ing of which demon­strat­ed a record 2.5 kW/kg spe­cif­ic pow­er at the cell lev­el at the company’s UK R&D loca­tion, paving the way for more than 3 kW/kg sys­tem lev­el den­si­ties in the next 24 months.

Devel­op­ing fuel cell tech­nol­o­gy for avi­a­tion is crit­i­cal to enable true zero-emis­sion com­mer­cial flight, and for ener­gy inten­sive appli­ca­tions like large fixed wing air­craft and rotor­craft, it is nec­es­sary to increase the tem­per­a­ture and pres­sure with­in fuel cell stacks in order to have a com­mer­cial­ly viable prod­uct.

Increased tem­per­a­ture and pres­sure allows for air cool­ing, reduces cool­ing drag, sim­pli­fies the sys­tem, and ulti­mate­ly enables much more demand­ing appli­ca­tions.

ZeroAvia’s team has made unprece­dent­ed deep tech break­throughs by deliv­er­ing a pres­sur­ized HTPEM sys­tem, inno­v­a­tive con­duc­tive coat­ings enabling the use of alu­minum bipo­lar plates in high­ly aggres­sive HTPEM envi­ron­ments, and a nov­el approach to advanced mem­brane elec­trode assem­bly.

HTPEM will sup­port ZeroAvia’s ZA2000 pow­er­train for 40–80 seat air­craft, as well as a range of rotor­craft and eVTOL appli­ca­tions. These fuel cells may also enable elec­tric propul­sion sys­tems for 100+ seat sin­gle-aisle tur­bo­fan air­craft such as the Boe­ing 737 and Air­bus A320.

The com­po­nents used in the ZeroAvia sys­tem have already been val­i­dat­ed through third-par­ty inde­pen­dent test­ing at sev­er­al inde­pen­dent labs, includ­ing a lead­ing U.S. Depart­ment of Ener­gy nation­al lab.

ZeroAvia’s recent break­through first flight of a 19-seat air­craft employed low tem­per­a­ture PEM fuel cell sys­tems for the sub-megawatt scale of small­er air­craft, but the low­er stack core tem­per­a­tures make it hard­er to remove heat from the larg­er sys­tems.

HTPEM tech­nol­o­gy elim­i­nates a num­ber of com­po­nents from the fuel cell sys­tem and reduces cool­ing drag, there­by enabling com­mer­cial pay­load and range with greater dura­bil­i­ty.

ZeroAvia CEO Val Mif­takhov said: “The com­pa­nies and geo­gra­phies that seize the lead in high fuel cell tem­per­a­tures and pres­sures will lead the indus­try, sim­i­lar to the sto­ry of tur­bine engines, where increas­ing tem­per­a­ture and pres­sure drove high­er per­for­mance.

“Hydro­gen fuel cell propul­sion is the most envi­ron­men­tal and eco­nom­i­cal alter­na­tive to exist­ing engines, and HTPEM is the most promis­ing route to deliv­er­ing these ben­e­fits into large air­craft cat­e­gories.”

Hydro­gen com­bus­tion engines remove car­bon emis­sions from flight, but face a steep envi­ron­men­tal penal­ty in main­tain­ing or increas­ing non-CO2 emis­sions, which are thought to have twice the cli­mate impact of car­bon emis­sions alone, accord­ing to a report from EASA.

Addi­tion­al­ly, a non-com­bus­tion, hydro­gen-elec­tric approach elim­i­nates extreme mate­r­i­al stress­es inher­ent in mod­ern com­bus­tion engines, which dra­mat­i­cal­ly reduces main­te­nance costs.

ZeroAvia’s devel­op­ment of the HTPEM sys­tems is in part sup­port­ed by the HyFly­er II project, backed by the UK Gov­ern­ment via the Aero­space Tech­nol­o­gy Insti­tute (ATI).

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Jason Pritchard

Jason Pritchard is the Editor of eVTOL Insights. He holds a BA from Leicester's De Montfort University and has worked in Journalism and Public Relations for more than a decade. Outside of work, Jason enjoys playing and watching football and golf. He also has a keen interest in Ancient Egypt.

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