Zinc Air Batteries
State of Zinc Air battery technology
Zinc air batteries were first deployed in 2011 by a company called Fluidic. The company is now called NantEnergy. These batteries are tricky to make work – other companies have tried, but failed, to make them. They have been used to provide battery backup for telecoms towers, or alongside PV arrays in national parks in the USA. A lot of them have been sold to provide battery backup of PV or mains power in remote areas where mains electricity is unreliable.
In a zinc-air battery, ordinary fresh air is blown onto the device and can percolate through a waterproof but breathable layer of material at the cathode. The oxygen in the air reacts at the cathode to form hydroxyl ions, which travel through an electrolyte inside the battery to a zinc anode, where they form zincate ions. That process releases electrons that flow through the wires to the circuit.
Charging the battery regenerates zinc at the anode and reverses the chemical process at the cathode. The energy storage potential can be increased by increasing the zinc in the battery. The maximum power can be increased by increasing the area of the cathode.
As a form of energy backup they are massively better than using diesel generators, which is what is often used in places where mains electricity is absent or unreliable.
Zinc – air compared with flow batteries:
- Both have the ability to decouple the maximum energy storage and the maximum power by physical system design
- Both enjoy a lack of flammability
- Zinc-air batteries have no internal moving parts so are very low maintenance
- Zinc-air batteries contain low-cost materials, so there is very little risk of them being damaged by people trying to steal anything from them, even if they are in remote environments.