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Thread: OT: New battery technology: fiberglass matrix + metallic sodium

  1. #11
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    I don;t suppose anyone suggests the sodium metal and water are in the cell.

    But "no danger" due to no water inside is not quite true. A substantial amount of sodium metal if submerged and there is a battery leak, that might just be a pretty serious danger, depending on how much there is, and what happened to the battery (and car) just before it went in the drink.

    You might find it rather easy to exit the sinking car.... if you were still conscious after the fire and explosion.

    Extreme? Sure.

    And it is inevitable that energy density going up means the device becomes closer and closer to being a bomb. It is simple physics. You have energy storage by preventing substances which release energy when they react, from reacting. To release energy you allow them to react at a controlled rate.

    If you LOSE control of the rate, a lot of the materials may react at once. That usually raises the temperature, since heat cannot get away fast enough, and temperature may increase the speed of reaction, ending up with a "boom".


    Quote Originally Posted by tlfamm View Post
    Regarding the safety of a sodium-based battery, I don't have free access to the Goodenough research paper, but found another discussing sodium-based liquid anode batteries:
    ....
    As the battery in the O.P.'s link is described as "all solid state", that would seem to indicate something other than a liquid in it. There is reference to plating the metal on the glass "electrolyte".

    No doubt there will be more details later, but certainly glass electrolyte, plated-on metals, and "all solid state battery" do not seem to describe a battery composed of liquid.

    Mind, I think a liquid electrode battery is a Very Good Thing with regard to the potential for a fast recharge. Drain and replace would be the method. But the meager data provided do not seem to be indicating a liquid system so far.
    Last edited by J Tiers; 03-20-2017 at 06:59 PM.
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  2. #12
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    Apparently sodium power cables are (or were, at least) a real thing:

    http://dx.doi.org/10.2172/5949513

    Ed
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  3. #13
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    They seem to be practical, even if only in buried and duct installations. Not in wider use because the savings were not enough over aluminum.
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  4. #14
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    Lithium reacts with water. Worse is sodium. Then potassium will be the next magic step in batteries.

  5. #15
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    Sodium also melts at a low temp, 208F. When the wires melt, their resistivity goes up, so once they melt, you have to reduce power so that they will solidify again. Wild.....

    The spectacular stuff only happens with a good deal of free water present. If it is just seeping into the cable, it corrodes the sodium, which eventually is reduced enough that it melts and probably breaks the circuit.

    The battery into the lake problem remains, though, if water gets into the battery in quantity, there could be stuff going on that you would not want to be sitting on top of. Lithium seems to be a bit tamer.
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  6. #16
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    It's easy enough to package batteries such that they are 100% waterproof. We do those things all the time. So I'm not as worried about foreseeable hazards when used as planned.

    I'm more worried about the guy who decides to "erase" his cell phone by smashing it with a hammer, then tries to throw water on it when it starts to smoke.

    It will be nice if they make a battery with 3 times the charge cycles and 3 times the energy density at the same price or lower.
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  7. #17
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    When you talk about safety in vehicles one needs to compare it to a tank full of gasoline.

    Also, the term "glass" can mean many things, such as "glassy iron".
    Last edited by Evan; 03-20-2017 at 11:21 PM.
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  8. #18
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    Quote Originally Posted by Evan View Post
    When you talk about safety in vehicles one needs to compare it to a tank full of gasoline.
    ...
    True enough. I guess I was thinking of the "safer than a lithium ion" comment. It's not like it is without hazards.

    Also see earlier comments about the similarities between ANY concentrated energy storage and a bomb. They are different hazards, but in the end, just about any uncontrolled release of energy is either in the form of heat, or an explosion, or both.

    Water and sodium is just ONE way that battery can cause a fire. There are other ways that are actually hotter than a gasoline fire, so you want to be father away.

    Gasoline burns and may explode. The hydrogen from the sodium reaction with water burns, and may explode. The lithium ion batteries can burn, and might even explode. Lead acid batteries burn, but may also explode. ANY battery can have a serious arcing failure with temperatures at and above welding arcs. The list goes on.
    Last edited by J Tiers; 03-21-2017 at 01:18 AM.
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  9. #19
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    Quote Originally Posted by Lew Hartswick View Post
    I dont see how a "glass" an be called an electrolyte. What is the definition of "electrolyte" ?? Look it up .
    ...lew...
    It's any substance that can make an electrically conductive solution. There are four different kinds, solid being one of them.
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  10. #20
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