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Conformable Polymeric Foams for On-Board Hydrogen Storage

Banyay_df_2_model
Pore structure of elastomeric polyurethane foam (27µm slice thickness)—one of the materials under investigation. Click to enlarge. Source: Ohio University MicroCT Facility.

Researchers from Ohio University, Inergy and DaimlerChrysler are exploring the use of conformable microstructures of polymeric foams for on-board hydrogen storage.

The Hydrostatic Pressure Retainment Microstructure stores the gas in small bubbles of a foam matrix, thereby forming a series of small, spherical pressure vessels. The resulting stress in the material between the bubbles is in a hydrostatic state of tri-axial tension.

The HPR approach has three main advantages:

  • Hpr
    Conformability. The conformable foam allows the tank to fit the frame.

  • Safety. In the case of an accident, only the gas contained in the adjacent cells to the fracture location would dispel at once.

  • Weight Savings. In theory, because the matrix material is in a state of hydrostatic tension, the material is being utilized 100% in all 3 cartesian directions, thus requiring less material.

However, neither of the two polymeric foams studied met the 2007 FreedomCAR goal for volumetric density of 0.036 kg H2/liter. One foam (DF-630A) delivered 0.0104 kg/L, the other (H130) only 0.0056 kg/L.

Looked at another way, while the target is for 8.18 kg of hydrogen in a 60-liter tank, DF-630A can hold 2.5 kg in the same volume, and H130 can hold 1.2 kg of hydrogen in the same volume.

The work is still in a relatively early stage. The team has developed an efficient method for examining polymeric foam for HPR applications, and note that composite foams could be used, which could greatly increase tank performance.

Next steps would be pursuing a composite foam, expanding the work beyond static structural analysis to consider thermal loads, potential chemical reactions, permeability and sorption rates, tank refuelability and cost—and then moving on to experimental tests of an actual hydrogen-pressurized tank.

Resources:

Comments

John Baldwin

What is the point of this?Does not seem to store much gas at all.

Brad

It's still in it's early stages, i'd imagine that later on they plan on making it able to store much more hydrogen.

Cervus

I think the issue at hand here is being able to more safely store enough hydrogen for a decent range (with either ICE or fuel cell) without needing to resort to 5000psi tankage that would explode violently in a collision.

SJC

I wonder how aerogels would work for this.
They are being used for hydrolysis.

"The carbon aerogel nanostructure provides a hydrogen/oxygen collection area that is 60,000 times the surface area of the aerogel"

http://www.greencarcongress.com/2006/09/llnl_licenses_c.html

Matt

Or, you could just use an electric car.

pizmo

Or, you could just use an electric car.

Do you have one?

Rafael Seidl

One of the problems with developing hydrogen tanks is that carmakers are not prepared to engage in enough lateral thinking. If you change the entire propulsion system of a car, you need to also redefine your concept of how the chassis should be organized. With a fuel cell, you don't have to deal with a hot exhaust system incl. aftertreatment and mufflers. Based on the volumetric density specified, you'd need a DF-630A tank with 787 liters capacity to meet the DOE target. That's 3.50m * 1.80m * 12.5cm, so in theory you could fit it inside a double floor underneath a raised passenger compartment + trunk. This sandwich construction would be load bearing (a potential crash safety issue) and provide acoustic as well as thermal insulation. People like to sit high anyhow (cp. SUVs), since it makes getting in and out of the car easier.

Mind you, I'm not advocating hydrogen in vehicles because it's just way too expensive to produce and distribute. Matt's quite right, if you're going to do drastic things, BEVs are more promising. All I wanted to point out is that on-board storage of hydrogen would be feasible if you were willing to change the rules.

Cervus

Article over at Slate on a Tesla test drive:

Eberhard says traditional carmakers have failed with electrics for two reasons. First, they market them as "penalty boxes" for environmental do-gooders and gas-mileage-obsessed penny-pinchers. Second, they just don't understand batteries. The Tesla's giant lithium-ion battery pack gives it the power to hit 60 in four seconds, to run 250 miles without a recharge, and to charge rapidly at its home charging base (a one-hour charge will take you 80 miles; it takes a 3.5-hour charge to go 250 miles). You can even plug into a wall socket at a roadside stop in a pinch. That makes the Roadster a viable commuter car and weekend day-tripper.

Moving in the right direction here. Their next model under development is a high-end sedan that will compete with a BMW 5-series. I imagine that they'll be able to do down market as their technology improved and costs drop.

pizmo

I'll be happy when Tesla moves out of the PR hype phase and actually has to deal with on-the-road realities.

Mark A

I agree with pizmo. Matt and Cervus, where is this electric car you are touting, or rather, this practical electric car. Give us an electric car with at least a 300 mile range, that can be recharged in the time it takes to fuel a gasoline car. It must have heat for the Alaskan winters, and A/C for the Arizona summers. Have at least a 3 year warranty, and be able to be financed for 5-7 years, with factory support. Seat four adults, and their luggage, in comfort. Oh, and the initial price must compete with similar sized gasoline cars. Until then, cars like the Tesla will be just toys for the Jay Lenos and George Clooneys of the world, to show off in, or, to gloat in.

Hydrogen storage technology is in its infancy, and has much room to develop. Much like the gas powered cars of the early twentieth century. Battery storage appears to be hitting a wall in regards to power, range and price. I hope I am wrong. I would love to have a battery powered lightweight two seat commuter type car the size of a Cobra, with no frills other than window defrost and light AC. Simple, easy to service, and inexpensive.

Neil

"Battery storage appears to be hitting a wall in regards to power, range and price."

Wall ... what wall? I've only been coming to this site for a year and I've seen significant progress in only that much time. More progress than I've seen in hydrogen storage.

If you're driving anywhere close to 300 miles a day burn bio fuel (or rethink your life).

The only big limitation on batteries right now is the price. The economics of the car depend on the price/availability of gas and how much CO2 you're willing to put into the air.

pizmo

The only big limitation on batteries right now is the price.

And recharge times. And range. And longevity. And cold weather performance.

Wall ... what wall? I've only been coming to this site for a year and I've seen significant progress in only that much time. More progress than I've seen in hydrogen storage.

They mentioned power, range, and price. Certainly price has dropped considerably for hydrogen (at least in the lab), and fuel cells have come down considerably as well. Storage of hydrogen per se is already at a point of acceptable range, per this article, and since quick fueling isn't a problem with this technology, it's mostly just economics at this point - which is obviously crucial.

Not sure how cold weather performance is coming along, though.

pizmo

correction: "... per the prior article [on the 350 mile range Explorer]..."

Neil

recharge times - overnight will work for 90% of the population .. I'm looking at puting some ultacaps in my e-cycle (200 km range) that will charge to 80% in 5 minutes. Altair batteries have similar recharge capabilities. I spend a lot less time charging my bike (all I have to do is plug it in) than I used to spend driving to a gas station. My house plug is always open.

range - if you drive more than 200km a day you should burn biofuel or take a serious look at your lifestyle (move closer to work). As the price of batteries comes down so the range of the cars will go up.

longevity - there are multiple batteries/ultracaps now being tested that have lifetimes longer than the car (firefly,altair,eestore).

Cold weather - I used to live in Yellowknife where it hovered arround -40 for long periods of time ... we used battery blankets. (actually we walked most of the time)

fuel cell prices are still stratespheric.

pizmo

recharge times - overnight will work for 90% of the population

Sure, and thermal solar has a relatively quick payback period. Never bank on Americans increasing their marginal effort.

range - if you drive more than 200km a day you should burn biofuel or take a serious look at your lifestyle (move closer to work). As the price of batteries comes down so the range of the cars will go up.

You're framing this in the form of lecturing to an individual, when what we're discussing is generalized behavior. People aren't going to take a serious look at their lifestyles, nor are they going to go out and get one biofuel vehicle and one electric vehicle.

longevity - there are multiple batteries/ultracaps now being tested that have lifetimes longer than the car (firefly,altair,eestore

All vaporware. Tesla estimate 125,000 miles on their battery pack.

Cold weather - I used to live in Yellowknife where it hovered arround -40 for long periods of time ... we used battery blankets. (actually we walked most of the time)

Now you've got people huddled around their home outlets (and making sure they don't draw down too much power while driving, just in case), moving their homes, buying biofuel vehicles as a backup, and putting blankets on batteries. Are we living in the same country?

fuel cell prices are still stratespheric.

Yep. Almost everything besides HEVs are either purely speculative technologies, or limited to marginal enthusiast tinkering.

mario

making the hydrogen in a efficient and clean manner is a larger problem than storage in my opinion.

Neil

Actually piz, I doubt very much we live in the same country (look up Yellowknife). Your right in that both BEVs and FCVs are only arround in limited numbers and not yet available to the general public. But lets look at who makes the BEVs and FCVs. The only FCVs out there are built by big companies with huge budgets. BEVs can be built in anyones garage. That tells me that what we have here is a race between the relatively easy to do vs. the massively funded. Only time will tell which one prevails. I'll be happy if either one can replace the fossil fuel ICE.

pizmo

Actually piz, I doubt very much we live in the same country (look up Yellowknife).

OK, same continent, Mr. Picky. ;) Still the same difference -- car-dependent, overconsuming, developed economies.

But lets look at who makes the BEVs and FCVs. The only FCVs out there are built by big companies with huge budgets. BEVs can be built in anyones garage.

That's sort of true. What's making the difference for Tesla is how well they're capitalized. Aside from the aesthetics (which are important, granted) they're not really doing too much different than the Tango in terms of price and performance. Crash testing costs alone make "garage project bootstrapping" essentially impossible. Many have tried that route and all have failed.

That tells me that what we have here is a race between the relatively easy to do vs. the massively funded. Only time will tell which one prevails. I'll be happy if either one can replace the fossil fuel ICE.

Seems to me that it's not going to be either/or. In the nearer term, HEVs are going to increase their battery capacity, which will bump their fuel mileage. Companies like Tesla are going to come in from the top end of the market and try to push down to more mass market vehicles. Diesels will start showing up with the BLUETEC vehicles and the new Honda technology, and if baseline oil prices stay high, some form of standardized biodiesel's going to take hold. Ethanol will continue to expand, especially in the Corn Belt, as long as it continues to get favorable CAFE rating treatment.

Meanwhile, there will be a whole host of non-automotive alternatives building up (some as demand-side reductions, others as technological alternatives like automated transit).

Hydrogen itself also has to be viewed in the context of how we get to a point of eventually relying solely on renewable energy. To get past the point of being a marginal, supplemental energy source, the mass storage problem is going to need to be solved (to deal with direct production fluctuations that occur because of wind, solar, and hydro variations - especially as the climate makes relatively rapid shifts that are difficult to predict).

It's all a fascinating process unfolding.

Rafael Seidl

Mark A -

given that many US families own more than one vehicle, I'm not sure it's necessarily true that a BEV must deliver the same performance specs as one powered by an ICE. There are plenty of people living in areas that rarely if ever experience severe winters but that do have severe air quality problems (SoCal for example). There are also plenty of people who need that second car only to commute to work and to run errands, typically averaging less than 30 miles a day.

In those cases, a small two-seater with a top speed of 85mph and 50mi range (down to 40% charge) that you hook up to an outlet in your garage overnight, or else to one provided at your place of work.

If the seats were behind one another (cp. the old Messerschmidt Kabinenroller, VW's One-Liter or Volvo's Tandem concept cars), the reduce aerodynamic drag to extend the feasible range. Note that the VW design was designed to meet modern European crash safety standards. The smart fortwo's tridion safety cell is another concept that could be adapted.

http://www.microcarmuseum.com/tour/messerschmittkr201.html
http://www.greatchange.org/footnotes-1-liter-car.html
http://www.autonet.ca/Spotlight/Concepts/story.cfm?story=/Spotlight/Concepts/2004/07/30/563484.html

Another concept that looks like a lot of fun and could work as a BEV is the leaning trike:

http://www.brinkdynamics.nl/
http://www.leftlanenews.com/2006/04/23/bmws-clever-concept-completed/

Note: all of these examples rely on ICEs. All I'm saying is they *could* be all-electric.

Neil

Speaking of different seating configuration the 2+1 Volvo electric concept car was pretty cool.

Piz ... I'll actually have to agree with your last post (most of it anyway)

SJC

"some as demand-side reductions, others as technological alternatives"

One demand side reduction I have favored is teleconferencing. A lot of the "knowledge workers" in our information age could work at least one week a day from their office at home. That could cut oil consumption right away.

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