1000 Mile Battery....

The reaction between aluminum and air does not seem fast enough or energetic enough for this purpose.

And yet they seem to be doing it, albeit for this small test case.

You can actually build one and test it yourself....Supposedly another of Tesla's inventions....

"...You'll need aluminum foil, activated charcoal, salt, water, a bowl, paper towel, two clip leads and a DC motor.

Create a saturated salt solution by filling the bowl with water and then pouring in salt and stirring it. Once you cannot dissolve any more salt in the water, you are done. Spread out a piece of aluminum foil next to the bowl. Fold over a piece of paper towel and soak it in the bowl, then cover the aluminum foil with the towel. Cover the towel with activated charcoal. Place one lead on top of the charcoal and clip the other lead to the aluminum foil. Fold over the aluminum foil to create a package (a burrito if you will) and then attach the leads to the DC motor. Nothing will happen yet. Press down on the aluminum foil and the motor should spin. The harder you press the faster it will spin. When you release the pressure the motor will stop."

http://www.brighthub.com/environment/renewable-energy/articles/117074.aspx

1 lb of aluminum is said to contain ~8kwh of energy and takes ~7kwh to produce, and the aluminum oxide is recyclable.....aluminum quote .86 USD lb.....

The aluminum contains more energy than it takes to produce? Sounds like perpetual motion or better...

"This reaction also nets approximately half a volt of electrical current."

Current isn't measured in volts, but in Amps. Seriously, how can air be the cathode? What keeps the electrolyte from going through the air and spilling out on the ground? How can DC current flow through the air which has a very high resistance?

The cathode typically consists of a layer of porous carbon or nickel, on which a silver or platinum catalyst is deposited on the inside. The porosity of the electrode is such that O₂ molecules can pass through it from the outside, but the electrolyte does not escape from the inside. The carbon or nickel electrode is also the current collector. The current does not flow through the air!

The O2 (from air) passes through the porous cathode where it meets the aqueous KOH electrolyte and reacts accordingly:

O₂ + 2H₂O + 4e^- → 4OH^-

Thus the O₂ molecule picks up 4 electrons via the external circuit and reacts with water to form 4OH-, thus replenishing the OH- ions which are being consumed at the anode. It is the OH- ions that carry the current internally from cathode to anode. Electrons are produced at the anode ("oxidation"), pass through the external circuit and load and are consumed at the cathode ("reduction"). Every anode/cathode combination will have its own voltage (emf), typically 1 - 3.7 volts. How much current per given area is produced depends on all sorts of things. Suffice to say, some battery types are much better than others. Some batteries can have a very high energy density but poor power density. The reverse is also true. The lead/acid battery gives plenty of power but is very heavy - high power density/lower energy density.

Thanks for the explanation. I appreciate it. I knew the current couldn't flow through air, but that's what the diagram showed. This is exciting technology, one that has been needed for a long time for electric cars and such.

Your mention of Tesla being the inspiration, or originator of the idea of an aluminum-air battery got me to searching to see if it was a verbal reference (which happened with Tesla) or whether he might have discussed it in more detail in his writings.

I have read 2 biographies of Tesla and yet never really read any of his writings which are, with the Internet, readily available; this being one instance. The writing that came up as a link when searching for aluminum battery and Tesla, is one, which he wrote, entitled, "The Problem of Increasing Human Energy." It is difficult to read because of the page width vs. the font size, but the latter half, especially, where he discusses power transmission via the Earth and deriving it from energy between the ionosphere and "ground," interplanetary communication, etc., provides a fascinating look into the working of Tesla's fertile mind and imagination. I knew of the general idea from the biographies, but had never read his actual words about the subject. It is clear that he was convinced of the practicality of his ideas, borne out by experiments he had done. He was eventually dismissed as an aging dreamer who got carried away with his ideas. I wonder...

Also interesting was his mention of detecting an error/oversight in one of Hertz's experiments.

I got sidetracked enough by this one writing that I didn't have time to look further for any mention by Tesla of the aluminum-air battery concept. But he mentions aluminum as the "future" metal in this one writing at length. So, I would guess, it exists, because it is mentioned here, too. I just don't have the time right now to find it. Or it might be in the very document I read through and I missed it. But I did search the page for the word aluminum -- which Tesla spelled aluminium -- and didn't see it connected with discussion of batteries.

ronseto recently started a thread about Tesla vs. Edison and it didn't spark (good Tesla term) me to read any writings. Your mention of him being the seed of an aluminum-air battery, ultimately, provided the impetus. So I appreciate the off-hand reference, as it got me to read, what is probably, one of Tesla's more futuristic writings. So, I will, now, make a similar post over there. (I also note that if one does a search on CR4 for Tesla, one gets 47 pages of post links. I'm sure reading through these threads would lead to further interest and inquiry.)

check this fluidic Energy

Researchers have tried to produce an aluminum/air battery since at least the 1960's. When I worked on fuel cells in that period, Alcan were in hot pursuit of the Al/O2 battery, but eventually gave up after spending millions. Like the Zn/O2 battery, they cannot be recharged with electricity (the former forms dendrites which short out the cell), thus being relegated to "primary batteries" - the anodes have to be replaced after each discharge and the electrolyte changed after several discharges - a messy business. Also, both types suffered from self-discharge - in other words the metal anodes slowly reacted with the strongly alkaline electrolyte (KOH), limiting their shelf-life. Nevertheless the military (cost no object!) had strong interest because of their high energy density and have used them.

Now and then both types have a resurgence in interest, but none seems to have succeeded, despite very positive press. I don't know why a non-aqueous electrolyte cannot be used, as in Li cells - it must have been tried. Let's hope they eventually succeed. But they would have to be rechargable (secondary batteries), because, as you point out, the energy differences between producing aluminum and its energy content is quite small.

"...the energy differences between producing aluminum and its energy content is quite small."

I don't see a problem with the energy content even if it was at par....It is basically just a transfer of energy, from a clean source hopefully, electrical power stored in the form of aluminum is just the same as hydrogen being used in a fuel cell....Pulling into a gas station to have your plates topped off, if significantly cheaper than gas, would be superior to plug in hybrids for some, who have no access to a plug where they park....and a 1000 mile range and storage for another 1000 if needed, gives new meaning to that emergency reserve gallon of gas some carry....

Good point!

I prefer this.... the closest so far. http://www.google.com/url?sa=t&rct=j&q=u.s.%20patent%207037620%20b2&source=web&cd=2&sqi=2&ved=0CDQQFjAB&url=http%3A%2F%2Fwww.batterypoweronline.com%2Fimages%2FPDFs_articles_whitepaper_appros%2FAppllo.pdf&ei=NF9SUd7uNIeZ0QHoxIEo&usg=AFQjCNHM6yG_XeC4_dZ_BCLZmwiLw_tb8w&sig2=AwBNlPT4Z4BUI4hZ_-ZOKg&bvm=bv.44342787,d.dmQ

Yes the Tri-Polar lead cobalt batteries....Haven't heard much lately(last 30 years), do you have one of these systems? The technology certainly did sound promising, but never seemed to materialize....

http://www.apolloenergysystems.com/

I read the Apollo Energy site blurb. I can't see anything there that wasn't done 45 years ago. I have to wonder who (and why?) is paying for their efforts to re-invent old technologies.

This may shed some light....

http://www.youtube.com/watch?v=U0LLQCLpOug

http://www.youtube.com/watch?v=KubHtZl8u-Q

http://www.youtube.com/user/TheDreamFactoryInc?feature=watch

So I think I'm getting the picture now......

http://www.youtube.com/watch?v=ZgOa22ZkCxM

In a manner of speaking yes. I am a party to the work at hand and contribute where needed. This is painfully slow, detailed and expensive but I will certainly tolerate any future comment that lauds his work (simply because it is unknown until now) as 'an overnight success'.

Are they selling the units now or still in R&D phase? If selling, what does the setup go for?

Ready to produce immediately upon final investment. The initial market investor will determine what they want ie 8, 12, 24 volt, configuration and size. The 8 volt is forecast at about 65 pounds, about 370 amp and 85% charge acceptance in 45 minutes from full discharge, ball park numbers from me. That is the limit to my permission.

keep your aluminum, I'm betting on zinc

That is very interesting! I have no idea how they manage to let oxygen and water vapor in, while excluding carbon dioxide, although it might have to do with the greater molecular weight of the CO₂ and/or the polar properties of the H₂O molecule.

Since the aluminum is consumed in the process, it seems like this should be called a fuel cell, rather than a battery.

The true definition of a fuel cell is that the system should remain "invariant." That is to say that the composition of the electrodes and electrolyte remain constant. To do this means that the electrodes must not be consumed and the products of reaction must be removed at the same rate that they are being formed. In the case of cells such as Al/air and Zn/air, the metal anodes are consumed and their products remain in the cell. They are therefore primary batteries. The oxygen consuming cathode on the other hand does remain invariant, so is a fuel cell electrode. So these types of cell are in fact hybrids - primary battery/fuel cell.

The most obvious real fuel cell is the H2/O2 cell, in which H2 and O2 (as air) are fed in continuously and the product - water - is removed continuously, by evaporation from the cathode air stream. The composition of the cell therefore remains constant.

I'll accept that!

How do you get electricity to flow through air, which is an insulator?

ever see a Tesla coil???