Breakthrough could slash R&D time for next generation of hydrogen fuel cells

Apr 04, 2012 By Marcia Goodrich
With PhD student Ezequiel Medici, Jeffrey Allen, right, has created a mathematical model that can predict the flow of water inside a hydrogen fuel cell.

(PhysOrg.com) -- It took Thomas Edison two years and over 3,000 experiments to develop a marketable light bulb. It has taken 10 times that long and who-knows-how-many experiments to develop a system that is far more complicated: the inner workings of a reliable, marketable hydrogen fuel cell.

Now a research team led by Jeffrey Allen of Michigan Technological University is nearing development of a that will slash that R&D time and effort. It focuses on , a fuel cell’s worst enemy.

Water vapor is the only emission coming out of the tailpipe of a cell-powered vehicle, a big reason why fuel cells are so attractive. But moving that water out of the fuel cell can be a soggy problem. Just a teaspoon can kill the reaction that drives powered vehicles. And, considering that it can take a stack of dozens of fuel cells to power a car, and a single flooded cell can take down the entire stack, water management becomes a looming issue.

Most of that watery action happens in the fuel cell’s porous transport layer, or PTL, which is not much thicker than a coffee filter. That’s where all the byproducts of the fuel cell’s power-generating reaction meet up with a catalyst and react to form water vapor.

It’s not easy to find out exactly what’s happening in the PTL. “Everything is compressed like crazy,” says Allen, the John F. and Joan M. Calder Associate Professor in Mechanical Engineering. “You have to get the gases—hydrogen and air—to the catalyst, and you have to get the water away. Figuring out how to do this has largely been a matter of trial and error.”

The latest generation of hydrogen fuel-cell engines does an excellent job of managing water, but as new materials and designs enter the arena, the industry is again faced with a long, costly experimental process to determine the best configuration.

“There’s a whole new class of catalysts coming out, and we want to make sure it doesn’t take another 20 years to optimize the materials set,” says Allen.

Optimizing those up-and-coming materials to get rid of water is especially difficult, because the movement of water in the PTL appears to be random. “But that’s what we’re trying to predict,” he says.

At high flow rates, water spreads out evenly. But when the flow rate is low, as it is in an operating fuel cell, it spreads out in irregular shapes like an amoeba, a process called “fingering.” Other factors come into play as well, including how saturated the PTL is.

Allen’s team incorporated those variables into a mathematical model with the aim of forecasting the movement of water. Then they tested it using four different types of PTL and found that they could predict how water would behave with a high degree of accuracy.

“We were really excited,” Allen says. “This is the first time anyone has validated a model in a real sample. We’re at the point where, by adjusting just one parameter, we are able to duplicate experimental results exactly.”

Now, the group has incorporated temperature and evaporation into their model to make it an even better tool for designers.

Allen and Ezequiel Medici, a Michigan Tech PhD graduate and postdoctoral research fellow, have published an article on their work, “Scaling Percolation in Thin Porous Layers,” in the journal Physics of Fluids, which was published online Dec. 23, 2011. Allen presented a paper on their most recent work, “Pore-Level Simulation of Multiphase Water and Thermal Transport in Low Temperature Fuel Cells,” at the Paul Scherrer Institute, in Switzerland.

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User comments : 13

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AWaB
5 / 5 (2) Apr 04, 2012
That's excellent if they can actually make a useful model that others can use.
bbdk
5 / 5 (3) Apr 04, 2012
It's all very well, but I must admit I am getting a little tired of could, should, may and perhaps when it comes to future energy technologies.
I could be on my way to becoming a grumpy old man, but please just do already.
Modernmystic
2.3 / 5 (6) Apr 04, 2012
It's all very well, but I must admit I am getting a little tired of could, should, may and perhaps when it comes to future energy technologies.
I could be on my way to becoming a grumpy old man, but please just do already.


^What he said.

It reminds me of my kids when they were young adults detailing an overly intricate plan about how they were going to get all their homework and chores done with sufficient time to play Xbox or get on facebook....finally one just has to say quit telling me and just do it...
djr
4.6 / 5 (5) Apr 04, 2012
I could be on my way to becoming a grumpy old man, but please just do already. Are you asleep from the neck up? Are you not aware of the Volt, the Leaf, the Bloom box, Ballard powered buses? - etc. etc. Mercedes is rushing a fuel cell to market for 2014 - http://www.inside...014.html the price will probably be outrageous becuz the technology is still expensive - which is why we need the innovation of this kind of project. Am I the only one who appreciates how much innovation we are seeing in such a short period of time? So many negative posts - sigh!
NotParker
1.5 / 5 (8) Apr 04, 2012
So many negative posts


You hate cheap clean shale gas. You and the STD's are depressing as you lie about shale gas and try and get companies to shift their jobs to China so more goods can be manufactured with coal power.
Manitou
5 / 5 (1) Apr 04, 2012
It's good to see Rowan Atkinson and Sean Connery working together on fuel cells.
djr
5 / 5 (2) Apr 04, 2012
"You hate cheap clean shale gas." Please show me anything I have said that indicates hating cheap gas. I think the price will go up soon - but that's just based on what I have read from Chesapeak. I like progress - I think that is the main factor distinguishing you and me. Bring on the fuel cells, PV panels - LENR, OTEC, wind turbines, wave generators, new nukes, thorium, geo thermal. The more and the faster - the better. We will go ahead and populate the universe with our intelligence - and I guess you will be left sitting in your puddle of oil - still making up shit - keeping the human race back in the fossil fuel era.
NotParker
1.6 / 5 (7) Apr 04, 2012
We will go ahead and populate the universe with our intelligence


If I could make you people pay for your own energy I would, but you parasites want renewables subsidized.

Cheap energy for 1000 years with gas and methane hydrates.

or

Poverty and doom and China/India owning the world is the future you want.
Estevan57
1.9 / 5 (26) Apr 05, 2012
NotParker, that doesn't relate to the article at all. What do you think about the article?
Why are you telling us what we want? Do you know us?

If you don't like what we say, go away. You don't have to stay and start another 12 page argument over renewable energy again.

I like your attitude djr. Nice post.
djr
5 / 5 (2) Apr 05, 2012
Poverty and doom and China/India owning the world is the future you want. How little you know. I want prosperity and abundance - for all 9 billion of us (or however many it gets up to). I see the infinite reserve of energy accessible as renewable energy sources as the best way to ensure that everyone has access to an equally high quality of life, and we don't destroy the planet in the process. Yes - I have a political agenda - I want everyone on the planet to have a high quality of life - that is also sustainable. I think it is possible - and coming in to being as we type. Leaving fossil fuel behind is necessary in my view. China and India are the 2 largest countries on the planet - so I do not begrudge them their opportunity to enjoy progress and prosperity - do you?
CardacianNeverid
5 / 5 (1) Apr 05, 2012
I am getting a little tired of could, should, may and perhaps when it comes to future energy technologies -bbdk

Unless you have crystal balls, you can't make definitive statements about the future.
bluehigh
2.3 / 5 (3) Apr 05, 2012
I can and do make highly accurate assessments of the future every moment of everyday. Perhaps due to information acquisition errors or faulty reasoning they are not always definitive. You could not even walk without highly probable assessments of the future. A crystal ball is not needed, only sufficient information appropriately applied.

bluehigh
Apr 05, 2012
This comment has been removed by a moderator.
Cynical1
not rated yet Apr 05, 2012
Blue, your last comment brought to mind a joke that wouldn't be appropriate to use here - but funny....:-)