The Audi Environmental Foundation is supporting Prodip Chatterjee’s Nunam project, which is giving a new life to discarded phone and laptop batteries.

18 December, 2020

Prodip Chatterjee is visiting his grandparents in India. While he’s there, he learns that many families in the neighbouring villages are still forced to live with frequent power outages, or even without daily access to electricity. 

“I’m disappointed every time to see that the poor living conditions hardly change,” explains Chatterjee, who is a German citizen of Indian heritage. But it’s precisely the electricity supply that is so essential to addressing the problem and improving the overall standard of living.

Three years ago, a brilliant idea occurred to Prodip while he was at work: “Many companies replace their employees’ laptops every three years. I thought that there must be some way to do something useful with the retired laptops. The batteries are there, and they still work – we just need to do something with them.” The idea that would later lead to the startup Nunam (Sanskrit for ‘for the future’) is born. 

Together with co-founder Darshan Virupaksha and other kindred spirits, he has been working on the creation of a renewable energy storage system since 2017. They carried out the initial experiments with old phone batteries and since 2019, they have been working on systems using retired laptop batteries, which are converted into new, mobile energy storage and charging stations. 

“In our pilot project, vegetable vendors use the mobile energy storage systems so they can light their stands after dark,” says Prodip, “which allows them to stay open for business. Aside from that, they can also charge their phones.” 

“We envision the second use case for users in their homes. In India, there are three devices that are especially important – smartphones, lamps, and fans. And our renewable energy storage unit can power an LED light, for example, for six hours,” he says. 

The used batteries are sourced from local scrap dealers and as a rule, can still have as much as two-thirds of their original storage potential still available.

We remove the cells from the old batteries and test them. The average remaining battery capacity is about two-thirds of the original capacity. It’s really crazy to think about how much potential just lands in the trash.”

“In addition to that, we also look at parameters such as heat development, internal resistance, and more. If — and only if — the batteries meet the necessary criteria, we install them in the new energy storage units.”

The issue of what to do with the storage units when, inevitably they do lose all of their charge is still one that is being addressed.
We have developed a few different approaches to solving that problem, says Prodip. 

“First of all, each cell has its own ID with a QR code so we always know where the energy storage unit with that particular cell is and what condition the cell is in. We developed an app and an online dashboard to track them. This allows us to use the usage data to predict how long the storage unit will remain usable. When the capacity begins to decline, we write to the buyer and arrange an exchange. Staying in close contact with the customer will be the critical factor in preventing the storage units from landing in the trash. 

“Secondly, we’ve considered offering a rental model in addition to the sales model. That means that the energy storage units have to be returned after a certain period of time.”

Like so many ideas, it is a simply one that has wide reaching benefits not only for those using the power units, but for the environment in general.