How do Fuel Cells Work?

An easy-to-understand but thorough explanation of the chemistry of fuel cells.

Category:

Education

Tags:

• chemistry
• physics
• renewable
• energy
• global
• warming
• hydrogen

[kasperzwemmen]

is hydrogen an energy carrier or a energy source?

[tdewitt451]

@kasperzwemmen it's an energy carrier, because it's not naturally occurring.

[cjforse22]

Great explanation. I have a few questions though:

Are fuel cells perfectly efficient at creating this reaction that only produces water? If not, how efficient are they and wouldn't the excess H2 be a volatile emission? Where do you get the pure hydrogen for the fuel cell process? Isn't it dangerous to transport pressurized H2? Does a fuel cell run hot enough to prevent water emissions from freezing in cold weather?

[tdewitt451]

@cjforse22 those are really good questions. efficiency of a fuel cell can vary widely; 50% efficiency is reasonable. however, that doesn't mean that 50% of the H2 is released as emissions; that means that only 50% of the fuel goes to make the electric current, and the rest goes to make excess heat (just like a normal gasoline engine does), which doesn't do anybody any good. But, that would explain why you don't have to worry about the water emissions freezing up.

[tdewitt451]

@cjforse22 But you really hit on the big question here: where do you get the hydrogen in the first place? Well, water is composed and hydrogen and oxygen, so you usually get H2 by splitting water in big H2 generation factories, using lots of electricity. But this presents a problem. Fuel cell VEHICLES don't make any harmful emissions. But in order to get the H2 in the first place, you have to use lots of electricity, and powerplants make lots of pollution. So fuel cells aren't perfect.

[tdewitt451]

@cjforse22 and finally, yeah it is dangerous to transport pressurized H2. (Just think about what happened to the Hindenberg, that famous airship that was filled Hydrogen and blew up.) however, engineers are getting pretty good at making hydrogen storage tanks safer and safer, even if you get into a big car accident.

[YoTeVeo5]

When you split the H2 into two positive atoms and two e-'s, where did the negative electrons some from?

[renegade3355]

@SuperKenny720

go retake Chemistry

[fhghfgjh]

hello I have a good question looks! I have problem with the part of the cell that separates the hydrogen from the material Eletron With what I can do that cell?

[DrTurf83]

@tdewitt451 Really nice video and explanation. You could also do steam reformating coupled with the water gas shift reaction to generate hydrogen on demand, or internally if your cell is of the SOFC type. Also, waste heat is not necessarily useless as you mention. If used in cogeneration the overall efficiency can reach ca. 85%, which is a significant improvement for typical values of 55-60% for SOFCs.

[mitchahbw]

@303KickAss -->wikipedia{dot}org/wiki/Prot­on_exchange_membrane_fuel_cell

[mitchahbw]

@303KickAss The barrier can be a number of things, but is the key to the principle. in this case he describes a PEM -->>

[rijumonsjb]

it was really amazing video. but dear I have 1 doubt, what material must be used fom the barrier which u used to separate H2 and O2 from each other? is it must me semi permiable? is it a metal plate? Please reply dear. I am confused about it.

Thanking u

[r1raceguy]

If some of the electrons are used to produce light or transformed into kinetic energy as would be done in use with a car, aren't some of the hydrogen molecules left without electrons to join up with? What happens to those H+ molecules? Can they merge with oxygen?

[casalejuan]

Hello, Do you know how can I make a solid electrolite?

[Tors1607]

very useful video, was struggling getting my head around fuel cells, I have a much better understanding now

[303KickAss]

Thanks you for this video. One question:

What is the "barrier" that only lets hydrogen though made of?