The self-healing zinc-air deep cycle battery

www.energymatters.com.au
5 Jan 2012

A US company states it has developed a self-healing rechargeable zinc-air battery system capable of 10,000 cycles-a 30 year working life. With applications including utility-scale energy storage; the argument regarding wind and solar power's intermittency will continue to weaken if the technology delivers.

Created by Eos Energy Storage, the Aurora Energy zinc-air battery is based on similar chemistry used in alkaline batteries that contain zinc and manganese dioxide; but in the Aurora Energy, the manganese dioxide has been replaced with a "thin air electrode". Oxygen from ambient air is utilized as a cathode reactant the company says, saving space and cost. Eos Energy Storage states the technology and components used in the Aurora Energy are safe, stable and recyclable. Zinc is also a plentiful metal and Australia is one of the world's top zinc producers.

The concept of a zinc-air battery isn't new, they are already in use as non-rechargeable batteries for appliances such as hearing aids and watches. However, many challenges have prevented the technology from being used in deep cycle energy storage applications. One of the issues has been electrolyte drying out over time as oxygen enters the battery. Eos Energy Storage says it has developed an electrolyte management and self-filling/healing system operation to address the issue.

Testing to date by the company has seen the Aurora Energy rechargeable zinc-air battery cycled over 2,000 times with no physical degradation observed. Eos Energy Storage says it is currently scaling up prototypes of its Eos Energy Storage Aurora Energy 1000 | 6000 Battery for initial manufacturing this year and delivery of MW scale systems in 2013. The Eos Energy Storage Aurora Energy will initially cost $1000/ kW/$160/ kW. For renewable energy integration and load shifting applications, Eos Energy Storage says the levelized energy cost will be among the lowest; comparable to pumped hydropower and combined cycle gas turbines.

Eos Energy Storage is also developing developing a zinc-air flow battery for use in electric vehicles, which combined with a lead acid battery system also created by the company will extend EV range to over 500 km and can be recharged for less than 2¢ per km.