Energy Storage; Is a Fuel Cell a Battery?

The key things in self-propelled vehicle design are:

• Power-to-weight ratio, which determines performance, and
• Energy-to-weight ratio, which determines range, and
• Aerodynamic profile, which also determines range.

It doesn't matter if it's a fuel cell, a tank of dinojuice or porage oats that supplies the power, frankly.

Excellent answer PW.

I think the Original question was really "can you run the fuel cell backwards? (energy receptor~ storage battery.)"

OR not. I could be wrong.

Your energy to weight answer covered it implicitly, I would state explicitly that the key with FUEL is energy density. That is why we will not see commercially viable Hydrogen cars in North America. Hydrogen contains about 1/24th of the miles per volume of Gasoline.

1/24th.

that means 24 tank trucks delivering fuel to your local "filling station" to give consumers the same number of miles as 1 tanker of gasoline.

Milo

And if Milo's supposition is correct, that the question is if a fuel cell can run backwards, the answer is no.

Thank you all, the answer is then no, a fuel cell is not a battery?

Your hydrogen storage reply is in direct proportion to to storage pressure, is it not? So you can store twice as much hydrogen in one cubic meter at 10,000 psi as at 5000 psi?

Finally, I am not talking about energy density alone, because on board generation can alleviate storage requirements. My question revolves around maximizing generation efficiency, or production density, if you will, along with energy storage density.

on board generation? Sorry, won't be going with you on this trip. The energy needed for onboard generation would be much more efficiently used to drive the wheels directly without losses by transforming. You are dangerously close to perpetual motion with the snippets of your concept revealed here. Milo

Great graphics... I am still laughing.

Fuel is not a power storage device. It is chemical reaction chamber in which hydrogen and oxygen reacts giving electron and water as by product. This electron generated is transported to storage facility which is battery or capacitor or at use facility which is cell phone, computer or camera for example.

The advantage I see from hydrogen fuel cells is the pristine waste products produced and that the energy released is electricity itself. If electricity is the energy form one is looking to get then not having to go through another energy transmutation can make this worthwhile. But as you mention later, a fuel cell is not capable of reversing the energy exchange. The concept of on board hydrogen generation from hydrocarbons does address the density storage problem of using gaseous or liquid hydrogen. However, one must now deal with the other carbon waste molecules generated by removing the hydrogen atoms from the hydrocarbon.

But I diverge from your point that I agree with. The primary advantage I see that electric vehicles can implement is the possibility of storing mechanical energy by dynamic braking instead of just throwing away the mechanical energy one has in the moving vehicle itself. So if one includes some super capacitors to store energy combined with a fuel cell to transmute chemical to electric energy to both top off the capacitors and to fight drag then there may one day be a more efficient electric vehicle than an ICE vehicle. Unfortunately the details on how one does this is far from being realized in a mass market design.

Palladium metal is good tank for storage of hydrogen safely. If super capacitor-and SOFC based fuel cell linked together then we get optimized MPG from any fuel we need and waste will be mainly water and carbon dioxide

" Palladium metal is a good tank for storage of Hydriogen safely."

At over $700 per troy ounce for PALLADIUM metal , even a teeny tiny tank better hold a whole crapload of hydrogen to be cost effective?

Milo

Used to be $230 per T.O. Think of this I would have made more than double of my money if I had this storage facility. joke!!

There are other metals and ceramics will also do but not as efficient as Palladium is but is good candidate

I hear you friend!

Yesterday almost always seems to have been the best tiime to buy.

How come we never recognize that today is yesterday for tomorrow?

Milo

The problem is not that today is tomorrows yesterday. The problem is should one buy or sell today.

_{Once again stating the obvious.}

Er, no it isn't.... it is HIGHLY permeable to Hydrogen because it catalyticlly breaks down H2 into atomic H which then passes through the membrane.

I see that palladium is capable of absorbing a large amount of hydrogen. I saw at Wikipedia and other cites that it can absorb a quantity 500 times its volume with only a slight increase in its volume. I'm not sure what that phrase means though because nothing was mentioned about a pressure for the hydrogen. I also do not see how one releases the hydrogen. I did find that this is "on going research" because there is still debate over where the hydrogen goes. Some think a hydrate gets formed but that implies water, others that mild changes happen to the crystal lattice that traps the hydrogen without any chemical bonds happening.

Regardless, this certainly is promising research but it is not ready for mass production.

My understanding of the process is that the hydrogen atoms settle into the interstitial spaces in the crystal lattice structure of the palladium. In order to release the hydrogen it has to be heated, and I'm not sure how fast or efficient the release of the hydrogen is. I suspect that a certain amount of hydrogen will remain in the lattice and not come out. I also suspect what is released is H, not H2, which is very difficult beast to contain.

Palladium membranes are used as filters to separate Tritium from He-3 (which is a decay product). Tritium will pass through and be absorbed, He won't.

Hi redfred. That 500 times number gives us something to work with.

How about a very crude back of the envelope approximation of the costs using that number?

Let's Assume 1 oz of $700 palladium can hold 500 times its weight (I'm thinking Volume is even worse!) in Hydrogen. And that gasoline mpg is 40. (just for the sake of discussion.)

We know that hydrogen is 1/24th the mpg of Gasoline.

so 1 oz of Palladium times 500 =500 oz of hydrogen held; 500/24= 21 ounces of "gasoline equivalent"

21 oz/128 oz/gal=0.16gal ; 0.16 gal times 40 mpg=6.56 miles

So that one $700 piece of palldium will hold the equivalent mileage in Hydrogen of 6.5 miles of travel.

Assuming 40 miles per gallon benchmark for gasoline, we get to pay $700 for just the capacity to hold less than 10 miles worth of driving.

100 mile range = 100 miles / 6.56 miles per oz = 15.24 * $700 per ounce =$10670 Just to hold the hydrogen fuel.

Nothing about Balance of Plant-Pumps, compressors, valves and regulating equipment, tubing, fittings, just palladium at todays prices. No inflator for price increase based on mass market demand...

PASS.

BTW, I know I am playing fast and loose with "ounces" here, but for a crude approximation, it serves its purpose. And I used weight, I'm guessing that Volume would make an even sorrier prospectus. I'll leave that for someone else to do. Back to my Charting!

Milo

It is done based on thermal metering technology. This is still work in progress and I am not involved in this. I know from my days of making resistor inks of silver palladium and palladium ink for thick film hybrid high reliability mother board use and one time had need to fire in formic gas atmosphere and end up other end palladium full of hydrogen and that time on started preaching this and now is the technology going in hydrogen storage.

Let's look at the pristine waste of hydrogen cars, i.e. water. Hot water. Imagine millions of cars sitting in traffic putting out water as steam or liquid. Now we have permanent rain in our cities, or at the very least permanently wet roads. In the north, we get millions of traffic accidents from black ice caused by hydrogen cars. But not for long. The dirty little secret is that the #1 greenhouse gas by far is water vapor. (They just shrug it off saying it isn't "resident" in the atmosphere, much like my tires don't matter because they aren't "resident" on the road.) So if humans are causing any global warming, the adoption of hydrogen cars will accelerate it. If nothing else, city dwellers can kiss the sun goodbye a la Blade Runner.

Although I do believe you are on the right track, ie noxious emissions versus energy expense/fear argument for improving transportation, this is like blaming the sport of baseball for your broken window.

That is a very obtuse argument with no basis in fact. On a comparative basis, if all of the cars on the globe were converted, the amount of water or steam they generate would be an almost unmeasurable percentage of the total standing water. As an additional observation, since we are debating the absurd, is that there would be no exhaust heat induced evaporation of existing water, so it may reduce water vapor concentrations. Any supporters?

have to say one of the answers that is a myth that is believed by most of the general public and scientific communities alike and shown here several times is the danger of on board production.

!) firstly Milo is correct energy to produce the hydrogen is equal to the energy produced at burn to drive the wheels the energy(batteries) would have driven anyway though there is a torque argument that is correct, the hydrogen will create more instant power and greater thrust but for a shorter length of time.

2) there is no need to pressurise on board production, you simply build the system with power to production required at the accelerator - increase electric input - increase H output, why would anyone even waste the space? no point.

hydrogen is best served as an inline production with the engine, no batteries required, and cut your fuel by about 50 percent. HHO is safe cheaper, than Icecream to have installed and is best because there is no tax or supplier control so the price can't go up for installs or fuel cells etc. there are basic systems already for sale that work to around 30 percent at the moment. Why wait having conversations about wishing - just do it and upgrade as better models become available.