Solar Power Storage Solution: Liquid Batteries

[OKIsItJustMe]

http://www.fastcompany.com/blog/kit-eaton/technomix/liquid-batteries-tech-make-solar-power-even-better

Solar Power Storage Solution: Liquid Batteries

BY Kit EatonMon Mar 9, 2009 at 9:53 AM

One of the biggest hurdles to more widespread use of solar power is that there is no simple way to store the excess energy produced, and peak energy demand doesn't always dovetail with sunny days. The latest attempt to solve this problem comes from MIT, where a team has invented an all-liquid battery that is powerful enough to store solar-generated electricity.

The problem of storing large quantities of electricity generated by eco power stations is that conventional battery tech isn't quite up to the job. Batteries have solid components that degrade, they take a significant time to charge up, they can be expensive and have a limited lifespan.



Hence the research into liquid batteries by Donald Sadoway's team of chemists at MIT. In the experimental new design, the battery is composed of three liquids mixed together--since they have different densities they form distinct layers inside the battery housing. Two of the materials act as liquid electrodes--molten magnesium and antimony--while the third liquid is an electrolyte like sodium sulfide.

When charging the battery, electrons are picked up by magnesium ions in the liquid, forming liquid metal magnesium and rising to the top of the battery. Meanwhile antimony ions lose electrons, and sink to the bottom as a layer of metal. This continues until all the metal ions are "used up" so that the battery is fully charged and there's only a narrow strip of electrolyte. When it's being discharged, the chemical process inverts and pushes electrons out until the liquids are back in their initial ionic state.

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[NYC_SKP]

1. Of course this applies to wind power just as much, if not more.

Solar is active during peak demand, which is actually very helpful in reducing the need for storage.

Wind is 24/7 and thus often not usable absent some way to store it.

As you indicate, storage is a big hurdle to widespread use of renewables, and it's a fascinating topic on it's own.

:patriot:

[OKIsItJustMe]

2. This also makes a possible way to recharge an electric car

It's almost as easy as filling a fuel tank.

[phantom power]

3. The bit where it's composed of molten metals seems energy-expensive to me.

I'm a bit dubious of their claims that it would be "cheaper."

[Bread and Circus]

4. I was thinking the same thing. Also, the world supply of that stuff might be limited.

[OKIsItJustMe]

5. TR10: Liquid Battery

http://www.technologyreview.com/energy/22116/page2/

…

Since creating the initial prototypes, the researchers have switched the metals and salts used; it wasn't possible to dissolve magnesium antimonide in the electrolyte at high concentrations, so the first prototypes were too big to be practical. (Sadowa­y won't identify the new materials but says they work along the same principles.) The team hopes that a commercial version of the battery will be available in five years.

[OKIsItJustMe]

6. Watch video here

http://link.brightcove.com/services/link/bcpid1827871101/bctid10224990001

[phantom power]

7. It seems clever in several ways.

I'm just imagining what kind of parasitic load you'd have in keeping the fluid electrodes hot enough to stay fluid. Maybe if they use a nice cylinder whose diameter is equal to its height, for maximum volume/surface ratio, and keep it very well insulated.

I imagine sloshing would be right out.