Lithium Air Batteries - Gaining Ground in Electric Vehicles and Grid Storage

The lithium air battery promises a lighter, longer-lasting, air-breathing power source for the next generation of vehicles and has grid potential.
Published: Tue 28 Jan 2014

The Electric Vehicle conversation has turned from ‘if’ to ‘when'. It is small wonder then that large motoring companies are showing a great deal of interest in the lithium air battery which could be powering BMW i3’s by 2017. Toyota Motor Corp and BMW have agreed to research the battery together.

Tesla has also been granted a patent for an electric vehicle powertrain which utilises the metal air battery to extend a vehicle’s range.

About the lithium air battery

The lithium-air battery has its anode filled with lithium, and cathode with air. The battery has the potential to store over 5,000 watt-hours per kilogram. (A123 M1 cells are around 120 wh/kg). That is over 40 times as much as today's high-performance lithium-ion batteries, and more than fuel cells.

The reduction in battery mass is achieved by eliminating the need for a second reactant inside the cell. Lithium metal batteries react with oxygen in the air which is pulled in through a 'breathing' casing, making them lightweight and compact.

Companies and researchers like the idea of an air battery because oxygen is abundant, free, and doesn’t need heavy casing to keep it inside a battery cell.

The idea is that the metal air battery for an Electric Vehicle will be ultra lightweight and possess a long-lasting lasting regenerative cathode.

Researchers, including IBM, are working to develop a lithium-air battery that will see electric vehicles run 800 kilometers on only one charge. Most fully charged lithium ion car batteries today will take an electric vehicle only 160 kilometers before petering out. (Nissan says its all-electric Leaf has a range of about 175 kilometers.) Plug-in electric vehicles such as the Chevy Volt have an even more limited range of up to 80 kilometers before its gas-powered motor must kick in.

Problems

As exciting as the technology is, metal air batteries are presenting a few problems:

 

  • The batteries could have a potentially poor cycle life - they can’t charge and discharge all that much

  • Safety issues in the lab

  • Poor energy efficiency

  • High costs

  • Difficult to recharge

A few companies and researchers are skeptical of metal air batteries. GM says that it won’t invest in this technology “as it does not provide a substantial benefit.”

Early Growth Stage

The global market for electric vehicle batteries is in the early growth stage and accounts for a large share of the vehicle’s total cost.

BMW board member Ian Robertson says that in the next three to four years there will be more progress in battery development than in the previous century. He predicts that electric cars will have batteries with twice the current power within four to five years, which will double the range. Tesla’s CTO JB Straubel says that battery innovation is improving around five percent to eight percent each year.

This means that core performance metrics will double every decade. This would be a major development for electric vehicles.

Electric Vehicle batteries transform the power grid?

Another exciting development, although still a long way off, is the use of these electric vehicle batteries as some sort of storage mechanism to help with stability and demand response.

Researchers in their development are also viewing electric vehicle batteries as a potential means of grid storage to extend their use cases which can only be a good thing for solving grid storage issues.

Startup, Eos Energy Storage, says that its zinc-air battery chemistry has the ability to provide grid-scale energy storage at very low costs. The company has just landed its first utility pilot partner to test it out.

Globally, the electricity capacity from vehicle to grid system is very small at less than 9 MW ( 2013,) according to Navigant Research data. However, it is expected to grow steadily over the next decade as car manufacturers begin to redefine their value, enter into earlier conversations with grid operators and experiment with various applications.