[Lezmaka]

Saw this story over at wired.com
http://www.wired.com/news/technology...,58436,00.html

I've been hearing more and more about how fuel cells are gonna replace batteries in mobile phones, pda's, laptops, etc.

People keep saying they're gonna be the next big thing since they can run the devices longer. There's one big problem though...

When the fuel cell is empty, you're screwed. You have to buy another cartridge or refill it somehow. You can't just plug into your cigarrette lighter or the nearest electrical outlet to recharge.

Unless something changes, it's gonna be like we're stuck with regular AA batteries again. Once they're dead, they're dead. You can't recharge em, you have to buy a new set.

Don't know how this would work, but a hybrid system would make more sense to me. The fuel cell charges a regular lithium ion battery (or some other rechargable battery). When the fuel cell is used up, you can just plug it into an electrical outlet, charge the battery and keep going.

[K.I.L.E.R]

Unless something changes, it's gonna be like we're stuck with regular AA batteries again.

Nicad batts are easily charged, I made a nicad charger. Still have it around, just never use it.

[Lezmaka]

Originally Posted by K.I.L.E.R

Nicad batts are easily charged, I made a nicad charger. Still have it around, just never use it.

That's because they are rechargeable. Old fashioned alkaline batteries aren't supposed to be recharged. Newer ones might be able to be recharged, but I seriously doubt they would perform like true rechargeable batteries (NiCd or NiMH).

[DemoCoder]

On the contrary, with fuel cells, presumably, after you use them, you are left with water. You empty the cell out, and refill it with fuel. Much faster than charging! Imagine refilling a fuel cell that lasts 8 hours in just 30 seconds. It is not the same as throwaway batteries. You don't throw away the battery, you just dump the water.

Think of it as charging your car. What's gonna be fasting? Filling it up with gas, or charging up an electric car?


If you're not near a refill station, presumably portable chargers will be able to produce the fuel on demand, perhaps through electrolysis. However, if fuel cells become widespread, and they are standardized like today's battery sizes, I'd imagine that you'd be able to get fuel anywhere, like from vending machines, stores, etc.

[Lezmaka]

I guess my point is that even if they do become as common as batteries sitting by every cash register, you'll still have to pay for them. With rechargeable batteries, you either use the outlet in a hotel (you really don't pay anything for that), in your car (like cell phones, pda's) or at home.

For a car, refilling a fuel cell doesn't really bother me, cuz you have to do it anyway with gas. I'm talking more about pda's, cell phones, laptops. I guess it depends on if you're willing to pay for the convience of not having to wait to recharge your cell phone, pda, etc.

[K.I.L.E.R]

Question: Are we talking about petrol as feul? If that's the case then forget it, feul cells won't take off that well.

[DemoCoder]

The fuel doesn't matter (could be pure hydrogen, could be a hydrocarbon). The point is, a battery is just a tank for energy, the only difference between your fuel tank in your car and your rechargable battery, is that you pour gas into one, and electrons into the other.

However, the other difference is, the energy density is alot higher in gas than in a rechargable battery, and "recharging" your car tanks only 1 minute, vs hours for a battery.


I don't want a rechargable battery that I have to plug into a electrical outlet and wait for *hours* to recharge so that I can have a few hours of usage.

I want to simply open up a hole in the battery, my cell phone, or my laptop, and pour in dozens of hours of usage.

I'm sure someone will build a fuel cell which can recharge by converting water back into hydrogen, but I don't want that, because it takes too long. I want to fill my laptop or cell phone up just like I fill my car.

As long as you can buy the fuel as easily as you can buy a can of coke today, or maybe it will be "on tap" everywhere like water, or generate the fuel yourself, I think I'd rather "fill er up" than "charge er up".

As for petrol as the fuel, it is more likely it will take off if it can be used in a fuel cell, since people can take advantage of the existing infrastructure for producing it.

Producing, containing, transporting, and manipulating pure hydrogen is a problem to be tackled, so in the interim, it is more than likely that some hydrocarbon extraction process will be used to get the hydrogen, rather than trying to get it out of water.

You are aware that when I say hydrocarbons in fuel cells, I am not talking about combustion, and emissions are next to non-existant from the hydrogen extraction process. In fact, you extract it from harmful "pollution" that gets emitted in the coal industry, therefore helping make existing energy production cleaner.

[Saem]

Producing, containing, transporting, and manipulating pure hydrogen is a problem to be tackled, so in the interim, it is more than likely that some hydrocarbon extraction process will be used to get the hydrogen, rather than trying to get it out of water.

Well gasoline isn't very stable, it has tendencies to burn when introduced to heat and so on. Hydrogen is a slightly tougher problem, but not by much.

[DemoCoder]

Building a reliable, lightweight, compact tank that can transport either gaseous or liquid hydrogen is "not harder than a petrol tank by much". It is much harder. I can store gas reliably in a thin aluminum can. Storing hydrogen, especially cryogenic hydrogen (which is needed to have sufficient energy density) requires much more sophiscated engineering. It is dangerous, and it is the number one reason we can't build an single-stage-to-orbit LOX rocket today, because a lightweight hydrogen tank is unreliable.

That's why people are trying to store hydrogen in metal hydrides or in hydrocarbons instead. Liquid hydrogen suffers from boil off (how do you like your car losing gas even when not running?), and it fatigues and corrodes tanks over time. You can store high pressure hydrogen, but then you have to build the tank even heavier.

Safe, reliable, hydrogen storage is nowhere near a solved problem.

[Mariner]

I vaguely remember reading an article about the use of carbon nanotubes to increase the amount of Hydrogen you could fit into a tank.

I think the gist of it was that by filling a tank with structures of carbon nano-tubes, you could increase the capacity for hydrogen gas manyfold. I don't believe they were talking about liquid hydrogen here, either. Sounds like an interesting option.

Not too sure of the details because I think it was probably the best part of a year ago when I read the article!

[PC-Engine]

Originally Posted by Mariner

I vaguely remember reading an article about the use of carbon nanotubes to increase the amount of Hydrogen you could fit into a tank.

I think the gist of it was that by filling a tank with structures of carbon nano-tubes, you could increase the capacity for hydrogen gas manyfold. I don't believe they were talking about liquid hydrogen here, either. Sounds like an interesting option.

Not too sure of the details because I think it was probably the best part of a year ago when I read the article!

Incidently NEC is using carbon nanotubes to build lithium ion batteries that last 10 X longer than today's offerings.