Warm Sodium Battery

There is some amazing news in the world of high energy batteries. Coors Ceramics thinks they have a way to make Sodium-Sulfur batteries that can operate at 90° C ( 194° F which is below the boiling point of water)and charge-discharge once a day for ten years.

The battery breakthrough comes from a Salt Lake company called Ceramatec, the R&D arm of CoorsTek, a world leader in advanced materials and electrochemical devices. It promises to reduce dependence on the dinosaur by hooking up with the latest generation of personalized power plants that draw from the sun.

Solar energy has been around, of course, but it's been prohibitively expensive. Now the cost is tumbling, driven by new thin-film chemistry and manufacturing techniques. Leaders in the field include companies like Arizona-based First Solar, which can paint solar cells onto glass; and Konarka, an upstart that purchased a defunct Polaroid film factory in New Bedford, Mass., and now plans to print cells onto rolls of flexible plastic.

The convergence of these two key technologies -- solar power and deep-storage batteries -- has profound implications for oil-strapped America.

"These batteries switch the whole dialogue to renewables," said Daniel Nocera, a noted chemist and professor of energy at the Massachusetts Institute of Technology who sits on Ceramatec's science advisory board. "They will turn us away from dumb technology, circa 1900 -- a 110-year-old approach -- and turn us forward."

One small quibble. Unless this technology can be used to make liquid fuels at a lower cost than oil, its uses in transportation will be limited. One drawback is that it needs to be kept around 90C for the battery to deliver juice. It will be hard to maintain that temperature with low losses in a Chicago winter.

Enough of the caveats. How about some more techno porn.

Inside Ceramatec's wonder battery is a chunk of solid sodium metal mated to a sulphur compound by an extraordinary, paper-thin ceramic membrane. The membrane conducts ions -- electrically charged particles -- back and forth to generate a current. The company calculates that the battery will cram 20 to 40 kilowatt hours of energy into a package about the size of a refrigerator, and operate below 90 degrees C.

This may not startle you, but it should. It's amazing. The most energy-dense batteries available today are huge bottles of super-hot molten sodium, swirling around at 600 degrees or so. At that temperature the material is highly conductive of electricity but it's both toxic and corrosive. You wouldn't want your kids around one of these.

The essence of Ceramatec's breakthrough is that high energy density (a lot of juice) can be achieved safely at normal temperatures and with solid components, not hot liquid.

Ceramatec says its new generation of battery would deliver a continuous flow of 5 kilowatts of electricity over four hours, with 3,650 daily discharge/recharge cycles over 10 years. With the batteries expected to sell in the neighborhood of $2,000, that translates to less than 3 cents per kilowatt hour over the battery's life. Conventional power from the grid typically costs in the neighborhood of 8 cents per kilowatt hour.

Re-read that last paragraph and let the information really sink in. Five kilowatts over four hours -- how much is that? Imagine your trash compactor, food processor, vacuum cleaner, stereo, sewing machine, one surface unit of an electric range and thirty-three 60-watt light bulbs all running nonstop for four hours each day before the house battery runs out. That's a pretty exciting place to live.

And then you recharge. With a projected 3,650 discharge/recharge cycles -- one per day for a decade -- you leave the next-best battery in the dust. Deep-cycling lead/acid batteries like the ones used in RVs are only good for a few hundred cycles, so they're kaput in a year or so.

My favorite caveat in projects like these is logistics. Or in layman's terms "how soon can they ramp up production once they have a working battery.

Grover's brother, John K. Coors, is CEO of CoorsTek, the manufacturing company that applies what the scientists at Ceramatec dream up. Their nephew, Doug Coors, oversees R&D.

With some 21 plants producing advanced ceramic products worldwide, the expectation is that full-scale production of ceramic sheets for the new batteries could be tooled up in short order. In fact, only a handful of CoorsTek facilities would likely be employed.

The order of magnitude pencils out along these lines: a target of 20 gigawatt hours of storage in 20 kilowatt-hour battery increments equals 1 million batteries. Or using a different metric, 1 million square meters of thin ceramic electrolyte would yield 20 gigawatt hours of batteries, equal to California's entire spinning reserve.

Nobody at CoorsTek even blinks at such figures. The company already produces 3 million pounds of ceramic material per month. "Once we have a working prototype battery with all the standards and cost requirements met, it will come up quickly," said Grover Coors. "It would scare people to know how quickly we can bring this up."

They're about about six months away from initial scale-up toward a commercial product, he said.

Lots of sodium will be needed to make the new batteries, and Ceramatec proposes a symbiotic relationship with the federal government to get it. Enormous quantities of sodium metals, the byproducts of nuclear weapons manufacturing, just happen be available for cleanup at Hanford nuclear reservation near Richland, Wash. It's a ready-made source of material that CoorsTek can recycle.

Of course once that source is gone they will have to pay full price for their sodium. Fortunately neither Sodium nor Sulfur are too hard to come by.

And what does all that talk about time to scale up mean? Here are my guesses. About a year and a half to pilot plant production. A year for battery testing and scale up. Another year to get a full production plant operating. So optimistically about 3 and 1/2 years. Realistically 5 years. Pessimistically 7 years. And very pessimistically never.

What would this technology mean? For one thing, besides its uses for wind and solar, it would be very handy for shaving peak loads. It costs the utilities a lot less to deliver steady power than to deliver power that varies a lot over the course of a day. Think of it as having a peaking plant and some backup power (for the refrigerator and furnace) in every home.

Of course superflywheels [pdf] might be a competitive technology capable of even more charge discharge cycles at roughly equivalent energy density.

H/T R. Dave Talk Polywell

Cross Posted at Classical Values