| Daihatsu is developing an alternative
fuel cell technology. It runs on hydrazine hydrate – a constituent
of rocket fuel – instead of hydrogen.
The chemistry eliminates the need for expensive platinum electrodes. Proton
exchange membrane (PEM) fuel cells used by OEMs such as GM and Daimler
feature acid electrolytes that need precious metal electrodes. Daihatsu’s
design has an anion exchange membrane and an alkaline electrolyte so cheaper
cobalt/nickel electrodes are possible.
Whereas PEM fuel cells combine hydrogen and oxygen to generate electric
current and emit only water, Daihatsu uses hydrazine hydrate and oxygen,
emitting water and nitrogen. But the hydrazine hydrate fuel is highly
toxic, especially in aquatic environments, and explosive when dry.
The firm says its design is low cost and offers similar power density
to hydrogen fuel cells. It is looking for further partners to help with
R&D on durability, performance, the storage polymer and infrastructure.
Daihatsu combines the liquid hydrazine with a polymer held in the fuel
tank, creating solid hydrazone. Circulating warm water through the tank
releases hydrazine, which then flows into the fuel cell on demand.
Safe storage of hydrogen in liquid, gas or solid states is also the subject
of intense R&D.
© Automotive Engineer, 2007
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