What if you do not have to plug your electric vehicle (EV), which uses expensive and heavy Lithium ion batteries, into an electrical socket for charging? What if there was a way lighter, cheaper and greener battery that uses just air, water and therefore the metal aluminium to get electricity and does the work more efficiently by giving a golf range that’s quite double that a Li-ion battery offers, that too without the necessity for electricity to charge it?
This could become a reality within the country a year or two down the road because of state-run oil marketing giant Indian Oil Corporation (IOC) and Israeli clean energy startup Phinergy that are performing on commercialising Aluminium-Air (Al-Air) batteries for EVs in India. A prototype has been developed with 25 Al-Air cells stacked in a series and is being tested in electric cars of Tata Motors, in electric trucks and buses of Ashok Leyland and in electric three wheelers of Mahindra & Mahindra. The technology behind Al-Air batteries is straightforward . The oxygen that gets sucked into the AI-Air cell from the air reacts with water and aluminium to get electricity. The simplest part is that when the Aluminum has been fully eroded, the batteries are often reloaded with a replacement anode (aluminium plate) and fresh electrolyte. For the buyer it means just swapping the used battery for a replacement one.
“What makes Al-Air tech attractive is that it’s has among the best energy density (energy stored for a given mass/volume) of 8 kWh per kg as compared to 1-1.5 kWh per kg of Lithium and others. That’s why an EV using the foremost evolved Li-ion battery offers only a 100-150 km range per charge, while with Aluminium, even with half the energy density, you’ll still get a fourfold higher range,” said Dr SSV Ramakumar, director-R&D, IndianOil. So, what makes Al-Air technology eco-friendly, safe and ideal for India? For one, AI-Air batteries require no electricity as they don’t have to be charged. Secondly, the aluminum hydroxide solutions generated within the used battery are often sent to a recycling unit to urge 100% aluminium back, explained Dr Ramakumar.
Al-Air tech is safer because it uses only a water-based electrolyte that’s free from toxins and features a wide selection of temperature operability, unlike Li-ion technology which uses organic toxins-based electrolytes that are highly inflammable, he added. Aluminium is abundantly available locally, while all lithium reserves are located outside India. Also, Aluminium being a light-weight metal there’s no negative consumption of energy thanks to the battery’s weight unlike Li-ion batteries that are much heavier, he added.
The sole hitch today is that as Al-Air technology has low power density, a reduced size Li-ion battery would be required to reinforce it as peak load operations and starting of vehicles require higher power density. Aside from e-mobility, Ramakumar said Al-Air batteries also can cater to stationary applications like powering mobile towers that currently run on polluting diesel sets.