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So Where Are The Fuel Cells?
prostoalex writes: "While fuel cells have been touted as a revolutionary innovation for the electronics industry, they have not hit the market yet. This article in eWeek talks about the current problems with fuel cells, and claims that 'these devices, designed to last as much as 10 times longer than a standard lithium-ion battery, should hit the market by 2004.'" There are a few fuel-cell devices on the market, but this article points out a few reasons they're not yet more widespread.
You're probably thinking mainly of the Hindenburg disaster when talking about something with hydrogen in it exploding. The problem with that is, A) the Hindenburg didn't explode, and B) it is highly unlikely that the fire that did consume the craft was caused by hydrogen being ignited by a spark. I got this from my dad and then later saw a report on it on PBS. Through a quick search on Google, I found the most relevant page I could, here.
The gist of it is that the skin of the Hindenburg was made of fabric and coated with laquers and metal based paints, and the material itself was highly flammable. (The guy on the PBS documentary had a piece of the original fabric and showed how nicely it burned.) That's why the entire surface of the dirigible burned within seconds and it crashed to the ground, and that's also why it burned with a bright orange flame. A hydrogen flame is nearly invisible in daylight; in darkness it's a pale blue. Hydrogen is lighter than air, thus always burns upwards, not in all directions. The long and short of it is that there were many indicators that a few thousand observant engineers and scientists over the decades should have picked up on, that should have told them their assumptions about hydrogen's involvment in that disaster were wrong. But to this day, the Hindenburg "explosion" is used in books and courses to show how "dangerous" hydrogen is. Just goes to show that just because something has been "known" a for a long time, doesn't mean it's correct.
While we were talking about this (dad and I), he also told me about some experiments he'd seen and/or done many years ago with hydrogen. For example, if you have a tank filled with hydrogen and poke a hole in the side, and light the stream of hydrogen that's coming out with a match, guess what happens? No, it doesn't explode. If it's dark, you'll see a blue flame right at the edge of the hole. You'll see it until there isn't any gas left in the bottle. The pressure of the escaping gas is always just enough to keep it from burning back into the bottle. But there's also another reason it doesn't burn back into the bottle and blow up. Say you stick that match into the hole, guess what happens? The hydrogen will put it out. Poof. Not enough oxygen. See, hydrogen is only flammable in the presence of oxygen. And it's only explosive in tightly confined spaces. So inside you're battery's fuel cell, you'd first have to mix it with a certain percentage of oxygen, while it's still sealed, and then somehow introduce a spark, inside the case, aslo while it's still sealed. Good luck.
Anyway, I just wanted to spread some updated information on the Hindenburg, and I've always thought that whole pure-hydrogen-puts-out-a-match thing really interesting.