Fuel Cell as a Battery

[peebee]

OK, so I'm pretty much of the opinion that if a hydrogen-based fuel cell serves any purpose whatsoever, it's pretty much as a replacement for lead-acid batteries. So my question is, how good a battery is a fuel cell? In terms of:

1. cost - my guess is batteries win, otherwise NASA wouldn't be about the only ones using fuel cells (based solely on practical justifications).

2. weight - no idea. My guess is lead batteries are heavier, otherwise NASA would be using batteries.

3. size - no idea. My guess is batteries have the advantage.

4. environmental considerations - Original energy source is not an issue UNLESS one technology is more efficient (and therefore requires less input energy for the same output). Assume hydrogen explosions are not a problem. We should account for nasty solar cell manufacturing processes, platinum membranes, etc, on the fuel cell side as well as discarded lead and acid on the battery side.

5. lifespan - batteries are typically replaced every 5-20 years depending on the battery, some are rated for 90. How long will a fuel cell last?

6. maintenance - there's 5 to 10-year maintenance free batteries, and 20-year high-maintenance batteries (check water & ph). What's the required maintenance on a fuel cell?

7. reliability - I'd assume a 10 year battery would last about 8 years. I'd assume a fuel-cell would be about as reliable as a battery for 80% of its life too. Any thoughts?

Any thoughts on which one looks like the best choice for stationary vs. mobile applications? Any other considerations I've missed? Anyone feel like defending the flywheel (or the "flux capacitor") instead as the energy storage device of the future?

 

[peebee]

PS -- we should also assume a "reasonable" density of hydrogen compression, whatever that is. . . perhaps a high-pressure gas? And that a "magic beer keg" has been invented to store the hydrogen, something that won't blow up but doesn't weigh a ton either. . . .

 

[peebee]

Oh yeah, one more criteria:

8. energy loss - batteries lose charge over time. Is hydrogen loss an issue, or will the fuel cell "retain its charge" indefinitely?

 

[EdStainless]

Like this?

http://www.pcworld.com/news/article/0,aid,118198,00.asp

= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.

http://www.trenttube.com/Trent/tech_form.htm

 

[peebee]

Sort of -- althought I was thinking more in terms of kWh than mWh batteries when I posted this. . . .

For mWh batteries, it seems like the only question is can they provide a higher power density than batteries, safely, with relatively good reliability and all at a reasonable cost. Any environmental benefit there over batteries would be incidental (with respect to market acceptance) -- if people can run their laptops and cellphones for two weeks straight off a fuel cell the size & weight of a battery, someone will buy it for nearly any price.