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Upp Fuel cell USB charger
Fraser:
As Mike and others have said. This is really strange product in that it cannot compete with current Lithium battery technology on price, size and performance. I like high tech gadgets but this product seems pointless and I wouldn't want one at any price. What were the development team thinking ? and why did no one in the companies that make these realise it was a pointless product. As I said, a classic case of a solution looking for a problem.
Fraser
mux:
First of all: best video ever. I'm pretty invested in the whole hydrogen fuel cell thing, so I watched with wide open eyes through the entire video. I'm the perfect audience for this video :P. Also, I've done a giant blog series on why fuel cells don't make sense for vehicles, but at least that's still a 100x better idea than this.
By the way, this fuel cell is an earlier model of one that was very recently in the news: http://www.intelligent-energy.com/news-and-events/company-news/2015/12/15/intelligent-energy-hydrogen-fuel-cells-significantly-extend-drone-flight-time/
This is a platinum nanoparticle dry PEM fuel cell. I.e. those layers in between the electrodes are: the oxidizer, a PEM (proton exchange membrane) and the reducer. The oxidizing and reducing films are gas-permeable and contain about 10-30g/kW of platinum, i.e. given that this unit seems to be 5Wp rated it's going to contain about 100mg of platinum total - a few bucks worth. Water is produced at the oxygen side, but there is so little hydrogen consumed that it's most likely just carried along the gas flow.
This fuel cell is going to be monstrously inefficient. The reaction potential (i.e. the voltage you expect when reacting hydrogen and oxygen) is 1.23V. This looks like 5 cells in series, i.e. at maximum efficiency (which is 83% theoretically) it would produce 6.15V. In the video, at no load it produces about 4.1V, i.e. it's about 55% efficient. At 100mA it drops to 3V, so roughly 40%, then 2A at 2V which is about 27% efficient. At that point just in the fuel cell itself, you're burning about 15W worth of hydrogen to produce 4W of electrical power, the other 11W is dissipated as heat. And then of that 4W, you need about 1W to power the fans and other electronics, and you lose another 10-20%ish in the power converter to 5V. Total system efficiency is going to be in the low double digits for this thing - at full load at least.
These cells have another issue; in order to get maximum power output, enough hydrogen needs to be pumped into the stack to make it all the way over the entire surface area of the PEM. This usually means they scale the fuel cell and pressure regulator such that there is about 10-15% overfeed of hydrogen. In larger scale fuel cell systems, the excess hydrogen is purged from the exhaust and reintroduced into the inlet (usually with a simple centrifugal separator + millipore filter), but in this design it's just exhausted. So you're probably also losing some hydrogen out the exhaust just to get the power spec.
This is not actually a good example of a fuel cell, though. Dry PEM cells are not made for efficiency or performance. The carrier mobility is at least an order of magnitude lower than wet cells, plus you're using it at a lower temperature than you'd ideally want (about 60-70C). The reason for dry cells is obviously one of practicality; you don't want to make some kind of miniaturized water pump system and all the issues that brings with it (hydrogen attacking your bearings, needing to have regulators and purgers to deal with the production and loss of water, etc.) just for a little bit extra efficiency. It'd be even heavier, bigger and more expensive.
So taking all of this into account, I'm extremely unconvinced that Intelligent Energy somehow produced a hydrogen fuel cell that can deliver enough power, do it reliably, cheaply and stay in business for long enough to support their drone fuel cell. The drone fuel cell is based on this exact same technolgy (dry PEM), they haven't invented something significantly different.
tszaboo:
For the price of that refuel, you get something like 6 AA lithium primary cell, or 15 Ah @ 3,6V . Lasts forever, almost no discharge, and you can make the power bank with a buck converter.
But if you absolutely need something for a flight, just use aluminium air batteries. Maybe even a potato battery makes more sense.
That is, the technology needs more development, because it is promising.
Synthetase:
Thanks for another great video, Mike.
I really don't understand the attraction of hydrogen as an (oxidation/reduction) energy source at all. I'm all for renewable energy, but hydrogen is so incredibly pointless. You lose so much energy in all the conversion steps between electrical power, to gas back to electricity. As you say, a modern battery pack has better storage capacity per unit mass over the fuel cell, you can charge it anywhere and you can run things from it directly without losing much energy to heat in the power source itself.
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