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Spotted: According to the International Energy Agency, EVs now represent around 18 per cent of total car sales, and this figure is set to see a 20 per cent year-on-year increase in 2024. However, there are still issues holding consumers back, including affordability and concerns over battery degradation and slow charge times.

Now, Indian energy tech startup Exponent Energy is working to advance rapid EV charging by developing a full ‘energy stack’ composed of the startup’s chargers, plugs, and battery packs. The battery pack, called the ‘epack’, integrates with a range of vehicles, and can be charged from 0 to 100 per cent in just 15 minutes when paired with the company’s own ‘epump’ chargers.

The company tackles two key challenges limiting the roll-out of rapid charging: extreme heat and lithium plating. Exponent highlights that 15-minute rapid charging generates 256 times more heat than 4-hour slow charging. If this heat is not managed effectively, it slows down charge times and quickly degrades batteries. The typical thermal management solution is to install bulky and expensive cooling systems on the vehicle. These are only needed during charging and add a lot of weight.

Exponent, however, takes a different approach. It deals with heat by ‘offboarding’ thermal management to the charger, meaning that vehicles powered by the epack are lighter. Under the startup’s system, the epump cools the epack by pumping refrigerated water through Exponent’s special connector, called the ‘eplug.’

The second issue Exponent’s technology tackles occurs when the lithium ions flowing from the cathode to the anode in the battery become ‘crowded’ at the anode. If this crowding becomes too much, the phenomenon of ‘lithium plating’ occurs, which leads to cell degradation. Through a combination of its battery management system, virtual cell modelling, and charging algorithms, Exponent can smartly manage crowding, dynamically altering the charging profile to prevent plating.

As a result of all these innovations, Exponent is able to provide a warranty for 3,000 charging cycles with 100 per cent rapid charging.

The 15-minute charge time can only be achieved when a vehicle equipped with the epack is charged at an epump. But vehicles powered by the company’s battery packs can also be charged at home or in one hour using any DC fast charging network.

At the end of 2023, Exponent has raised $26 million in a series B funding round. The startup is also working with a variety of partners, including Park+ to turn car parks into fast-charging hubs, as well as with companies like Fyn Mobility, Alt Mobility, and Montra Electric. And in April, Exponent also launched a fast-charging three-wheeler in collaboration with Omega Seiki Mobility.

Written By: Lisa Magloff and Matthew Hempstead