“Lithium batteries scare me more than hydrogen fuel cells.”
Seen here are a plates from a hydrogen fuel cell fabricated at the U.S. Naval Research Lab. The quote above is from NRL researcher Karen Swider-Lyons who spoke at an Xponential technical session on power sources for UAVs. She was referring to the hazards of high-energy lithium batteries versus the difficulties of storing hydrogen under pressure as a fuel source for fuel cells.
NRL has several efforts aimed at creating practical H2 fuel cells, both as alternatives to lithium batteries and eventually as replacements for internal combustion engines. Swider-Lyons expects the cost of H2 cells to drop partly because automakers are perfecting fuel cell technology for mass production. Some NRL fuel cells, for example, now use the same proton-exchange membrane material found in the hydrogen-powered Toyota Mirai.
Another NRL project aims at creating a stackless fuel cell: The skin of the aircraft forms part of a fuel cell. Rather than pumping air and hydrogen through channels in a fuel cell stack, airflow over the wing provides oxygen and removes water by evaporation. Low-pressure hydrogen sits in the wing on the other side of a membrane electrode assembly on the wing surface. The resulting structure isn’t as efficient as a conventional stacked fuel cell, but it potentiall brings a dramatic reduction in weight.
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