I came across this the other day. Not suited for vehicles, but an attempt to store excess grid energy in huge quantities using batteries made from relatively common materials (not the rare earths that have been discussed.)
Without doing a calculation, energy density seems to be quite high. The interesting thing however is the pursuit of what looks to be a very innovative and promising idea.
Donald Sadoway – TED talk on liquid metal batteries. Approx 14 mins long.
Cool tech. How is it better than just pumping water uphill as an energy storage?
Molten salt batteries have already been used to power cars.
http://en.wikipedia.org/wiki/Molten_salt_battery#Vehicles
http://en.wikipedia.org/wiki/Think_City
I’m not sure if this failed because of a problem with the basic concept or a failure to scale up production quickly enough.
I’m intrigued with a hybrid car where the batteries are charged with a micro gas turbine running a generator. This would be much more efficient with natural gas than a piston engine. The gas turbine can charge the batteries quickly or run the electricity to the motors directly.
It might not be.
It is still in the developmental stage. I don’t know what the losses are in charging / discharging. I would imagine that there is significant energy loss as heat due to the elevated temperatures. you would probably want to thermally insulate the crap out of that thing if it was in a 40 foot container as they have suggested.
whether those losses would be greater than the losses experienced when pumping water to a height for later hydroelectric generation – I don’t know. I would imagine that the response time of a battery would be significantly quicker than hydro storage, and the ability to employ this technology at a more local level may be an advantage.
Added to this, I am not sure how available antimony is. I envisage some problems in obtaining the many tonnes needed to roll out this tech on a significant commercial scale.
I just admire someone who goes out on a limb, and this tech does show some promise. If you had a bank of these batteries parked on the outskirts of a small town and had all the farms in the area plant a few wind turbines, you might have a serious level of independence from the grid.
Or because, you know, “ohmigod I’m covered in molten salt!!!11!!111”
Actually, current research is working on a sort of capacitor/battery hybrid. That is, they are capacitors, but have electrochemical processes to help store charge. They don’t discharge quite as fast as a plate capacitor, but that’s not their intended purpose.
The biggest problem that I see is that they need to be kept hot or they won’t work (it sounds like they aren’t damaged if they cool, but it can take a while to reheat them). On the other hand, they could be much cheaper to make because they can use widely available materials, and good insulation can reduce heat loss. Also, not all molten salt batteries need to operate at such high temperatures; the Wikipedia link says they can operate at temperatures as low as 135°F, still hot enough to burn flesh (but not instantly) but not “sets everything it touches on fire” hot (NaCl melts at 1474°F).
That is what I read also. It makes more sense in a vertical application, like a delivery vehicle or a taxi, where there can keep it garaged and keep it plugged into the heater when it isn’t in use, so the battery stays molten.
With our current technology, battery powered cars are a tough sell. They would be better as a 2nd car that is a dedicated commuter vehicle that is light weight and designed for one or two passengers and cheaper than a conventional vehicle.
Has Battery Capacity Reached It’s Maximum?
The one in my cell phone just did.