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Hmm, what about lithium air batteries, and fuel cells, and all the other things that we hear about having 10x the energy density?
by tocomment 14y ago
Hmm, what about lithium air batteries, and fuel cells, and all the other things that we hear about having 10x the energy density?
- runeks 14y agoHaven't heard about "lithium air batteries" but I'd say fuel cells aren't batteries since they basically just oxidize methanol (which is what an engine does with gasoline). But the lines might be more blurred than my thinking indicates.
- ars 14y ago> I'd say fuel cells aren't batteries since they basically just oxidize Many batteries also use oxidation reactions. That's not how you define a battery. I think the main difference is batteries release all the energy as electricity without associated heat, but fuel cells are partially electricity, partially heat.
- frankus 14y agoFuel cells are just "open" batteries, where the reactants are continuously fed into the battery and the products are removed (whereas in a battery the reactants and products occupy the same physical volume).
- ars 14y agoThen what distinguishes a fuel cell from a http://en.wikipedia.org/wiki/Flow_battery http://en.wikipedia.org/wiki/Flow_battery ?
- kylebrown 14y agoI'm pretty sure you're mistaken. The battery you describe violates the Second Law of Thermodynamics (no system can ever be 100% efficient). Both batteries and fuel cells (and any other open physical system) will lose some energy as waste heat in doing their work (producing electricity).