Zinc Air, the Lithium Alternative?

February 24, 2009 – Vol.13 No.49

ZINC AIR, THE LITHIUM ALTERNATIVE?
by Bruce Mulliken, Green Energy News

Energizer, recognized by its energetic electromechanical stuffed Bunny that keeps going and going, has a new energy storage device it’s just beginning to market: the Prismatic Zinc Air battery. Prismatic means that it’s not coin shaped or cylindrical like many small batteries, it’s rectangular and squarish.

It’s a little thing, offered currently in three sizes all not much bigger in area than a postage stamp. All are 5 millimeters thick, less than a quarter of an inch. It’s a larger sibling to Energizer’s zinc air hearing aid batteries. The battery maker is hoping electronics developers will use it to power small hand held electronics like cell phones or calculators.

Prismatic Zinc Air is not rechargeable. But it should have a really long run time, perhaps three times that of lithium. Given the history of its own zinc-air hearing aid cells as well as other uses of zinc air chemistry, the company isn’t bragging about its performance.

The company says the technology has the highest energy density of any consumer portable power solution, either disposable or rechargeable.

Energizer has said nothing about the use of its zinc air cells to power cars. That’s the kind of thing that I dream about. There’s nothing new about zinc air chemistry vehicle applications. It’s been done in the past with excellent results. It’s rumored that Toyota is experimenting with the technology for hybrids or electric vehicles.

The electrochemistry of zinc air is very similar to that of standard alkaline chemistry as found in flashlight batteries. In the related chemistries, zinc in an oxygen-rich electrolyte corrodes inside the devices, and as it does, an electric current is available for use. With zinc air chemistry, atmospheric air, with its oxygen component, is allowed to bubble into the electrolyte thus more zinc corrosion, and more electric current is available for use. The electrolyte in Zinc air can be as simple as sea water. The reaction between the metal in the electrolyte and another metal that won’t corrode away is the galvanic reaction, the basic electrochemical reaction for all storage batteries.

The reason I’m focusing on this particular battery from Energizer is a deep concern that batteries with lithium as a major component will never be cheap enough to be viable for cars. Many electric car developers are banking on lithium (and don’t get me wrong lithium makes for some great batteries), but if lithium fails to come through and prices don’t drop (like about 90 percent) then electric car development could come to screeching halt.

For electric vehicles to be feasible the batteries need long run times (which zinc air offers) and be cheap (which zinc air offers, but right now lithium doesn’t.)

There are some teasers that Energizer throws in when describing the new battery that may hint that they’re actually thinking about these things for cars. Energizer says the batteries need to be valved and throttled. Valving, a way to shut off the air supply to the battery, will be able to stop the reaction in the cell. In essence, turn it off. Throttling describes how the power output of the cell can be changed by controlling how much air is allowed in.

Both words, valve and throttle, sound more like car components than battery functions.

Since no device has yet been developed that will accept the batteries, the company is holding design seminars to encourage product engineers and designers to develop products that would employ the batteries. Those electronics would have to utilize throttles and valving to make the batteries work optimally.

Since the batteries are for one time use, electric vehicles would not be recharged but have batteries swapped on the fly, like a portion of the Better Place business model for electric cars. Zinc oxide within the batteries could be recycled. Zinc is plentiful on the planet. Lithium is not.

To get original equipment manufacturers (OEM) interested in the Zinc Air Prismatic products Energizer is holding a series of design seminars. The seminars will be held the week of March 16 in Silicon Valley, California, Newport Beach, California, Chicago, Illinois and New York City. Seminars will focus on providing device designers with the knowledge they need to utilize Zinc Air Prismatic in their new products. Specifically, the seminars will feature an overview of the product technology, a description of the types of air management needed to allow the battery to perform at its best, an in-depth look at the battery compartment design, and a window dedicated to questions and answers. OEM designers interested in attending a seminar should contact Stevie Lewis at 314-552-6713.

Energizer is not alone in pursuing zinc air technology for personal electronics. ReVolt of Switzerland is working on rechargeable zinc air chemistry that will also have an energy density three times that of lithium.

Lithium batteries began life as power for small electronics. Maybe zinc air is just getting started.

Links:

Energizer Holdings
http://www.energizer.com

Energizer Zinc Air Prismatic Technical Product Information
http://data.energizer.com

Better Place
http://www.betterplace.com

ReVolt
http://www.revolttechnology.com

--- Energizer Introduces Zinc Air Prismatic Battery for Consumer Electronics.

--- ReVolt Technology, Ltd Receives Additional 10 Million Euro ($13 Million) B Round Investment.

--- Better Place Joins Subaru, Other Carmakers, in Japanese Electric Vehicle Demonstration Project.