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Power trip

Rechargion’s sodium-ion batteries — safer, greener and longer lasting than their alternatives — could be a boon for rural India

In March 2022, a ship carrying a fleet of luxury cars from Germany to the United States, caught fire in the Atlantic Ocean and sank, taking with it millions of dollars’ worth of precious cargo. The cause of the fire was said to be the overheating of a lithium-ion (Li-ion) battery in one of the electric cars being transported. After burning for days off the Portugal coast, the ship finally went down.

Manjusha Shelke, founder director of the startup Rechargion Energy, wants to help make sure accidents of this kind never happen. “We have instances of electric two-wheelers in India catching fire, even mobile phones,” says Ms Shelke. “That’s because people do not know the inherent issues with Li-ion batteries. They are volatile and, if not protected by proper thermal management systems, can burst into flames for several reasons.”

Rechargion Energy, which has been funded and backed by Social Alpha, an organisation supported by the Tata Trusts, is trying to find an alternative to Li-ion. Years of research later, the company has found a relatively stable substitute in sodium-ion batteries (SIBs), which are safer and greener.

Ms Shelke and her team are working to set up a battery manufacturing pilot plant, with funding from Social Alpha and the central government’s Ministry of Heavy Industries, and they expect the first lot of SIBs to be manufactured by early next year.

The farm equipment space would benefit from Rechargion’s sodium-ion batteries
The farm equipment space would benefit from Rechargion’s sodium-ion batteries

Longer the better

The Rechargion team wants to make the batteries last longer, so that they may be used in a variety of applications in agriculture and as storage units for power generated through wind and solar energy. That would be a boon for rural India. SIBs would also make electric vehicles safer and, in time, cheaper.

“We need more stable batteries in the push for e-mobility in India,” says Ms Shelke. “In the same way, if we stress the need for more clean energy from solar or wind, we must have storage devices that can capture and preserve the intermittent energy generated by these sources.”

Li-ion batteries, which can power multiple devices, are seen as somewhat unpredictable. But, according to Ms Shelke, there are few alternatives available in the country. There being no operational Li-ion battery manufacturing factory in India yet, the batteries are imported from China, which has a comparatively larger amount of lithium resources.

Recent reports that lithium has been located in Kashmir and Rajasthan are intriguing, Ms Shelke says, adding that it would still be a finite amount, and may not be enough to fuel the country’s energy storage needs sustainably.

“Right now we are dependent on the Gulf countries and Russia for oil and fossil fuels,” says Ms Shelke, “and we are dependent on China for Li-ion batteries. It’s not a good situation for us.” Self-reliance and independence from imports is a big part of finding an alternative.

Rechargion’s research and work have shown that SIBs fit the bill. The main component, sodium, is easily available, says Ms Shelke, and the rest of the materials used in the battery are mostly surface elements, so no elaborate mining is required.

In terms of its chemistry, sodium ion is the closest to lithium ion, and both can be fabricated in the same factories. Also, while Li-ion batteries need to have some charge before being reused (an electric vehicle battery cannot be allowed to run out completely), SIBs can be discharged completely before storing and shipping, which makes them safer. SIBs can, additionally, be recharged much faster than Li-ion batteries (depending on grade, they get to full power in about 15 minutes).

“Technically, SIBs can replace Li-ion batteries in any application,” adds Ms Shelke, “and the lifecycle of SIBs is longer.” Where Li-ion batteries last for 2,000 to 3,000 cycles of use, sodium batteries run for as many as 5,000. Depending on use, they could stretch for up to 15 years.

Such longevity would be useful in a farm setting. More important, says Ms Shelke, is the safety factor. People in rural India use lead-acid batteries in their equipment and as remote storage. These batteries, which are prone to leaks and melting, are extremely harmful to both humans and the environment.

Cheaper option

Farmers in India use a lot of diesel-powered equipment: tractors, generators, cutters and such. SIBs could, in the circumstances, replace diesel as a cheaper option. “We can potentially replace Li-ion batteries in any kind of farm vehicle or equipment,” says Ms Shelke.

Perhaps the best use of SIBs are as power-capture units. Wind and solar energy can be channelled into these and preserved for later use. ldquo;That’s one of the biggest markets for these batteries, as a ‘grid storage’ for renewable energy,” says Ms Shelke.

In remote primary healthcare centres with erratic power supply, they could save lives by enabling medical equipment or cold storage units to work continuously. In homes in both rural and urban areas, SIB packs can be used to decentralise energy, which means taking energy from the grid and storing it in a hub.

Says Ms Shelke: “Our SIBs would be particularly useful in rural India, where people are unwittingly using electric scooters powered by lead-acid batteries, not even Li-ion.” The next possibility is home-based power storage solutions and, of course, farm equipment.

Ms Shelke estimates Rechargion’s SIBs will cost 33% less than Li-ion batteries. “Lithium iron phosphate-based batteries are the cheapest in the Li-ion category, and their cost is about $150 per kilowatt hour (kwH). We estimate that SIBs would be around $100 per kwH.” With a lab prototype ready, Rechargion plans to roll out its product on track.

Social Alpha has stepped up, as it does for all its partners, with part-funding of the battery plant and helping the Rechargion team put their backend efforts, such as financials, in place.

“We are scientists and we don’t know much about running a company,” says Ms Shelke. “Social Alpha came in and put it all together for us. It is an amazing experience to be associated with them. We trust them blindly.” Much in the way Rechargion hopes customers will view its SIBs.