How does Exponent Energy's 15-minute rapid battery charging work?

Energy tech startup Exponent Energy today showcased its proprietary energy stack - battery pack (e^pack), charging station (e^pump) and charging connector (e^plug) that together unlock a 15-minute rapid charge and long battery life (3000 cycle life warranty 3 times the industry standard) – all done on regular LFP cells for which it says the first time in history.

The startup said this two-sided approach, electric vehicles will be 30% more affordable and reduce EV charging costs by 33%.

"Our energy stack addresses two key problems that, for decades, prevented rapid charging on LFP cells – Lithium plating and Extreme heat. Tackling Lithium plating to prevent significant cell degradation When charging a cell, Li-ions flow from the cathode to the anode and get absorbed. The faster you charge, the more ions flow, leading to crowding around the anode. If left unchecked, this crowding leads to lithium plating, resulting in significant cell degradation. Exponent solves this through a combination of their Battery Management System (10 times more accurate than industry standard), Virtual Cell Model and Dynamic Charging Algorithms," the startup said in a statement.

Exponent Energy further said that this allows them to proactively sense Lithium crowding in real-time and ensure each cell is rapid charged without significant degradation and was validated by an independent testing laboratory - TUV India (TUV Nord Group, Germany) that found only 13% degradation after 3000 charging cycles of 15-minute rapid charging. Off-board thermal management for rapid charging in any ambient temperature 15-minute rapid charging generates a ton of heat. 256 times more than the industry average of 4 hour charging. If this heat isn’t extracted, the battery pack would overheat and switch off. 

In response to the challenges of rapid charging in high-temperature climates, Exponent Energy has developed an off-boarded HVAC system, which uses the e^pump to transfer refrigerated water through the e^plug, ensuring that each Li-ion cell in the e^pack stays below 35°C during rapid charging.

The ambient temperature in India can reach 40°C or higher, far above the preferred 25-35°C range for Li-ion cells. By moving the typically bulky and expensive cooling system outside of the vehicle, Exponent claimed that its solution allows for more affordable and lightweight electric vehicles (EVs). 

Speaking on the occasion, Arun Vinayak, CEO and Co-founder of Exponent Energy, said, “At Exponent, we’re building the future of energy that combines cutting-edge engineering with real-world economics, and our off-board thermal management system is a testament to that belief. For everyone to go electric, consumers need EVs that charge faster, last longer, and cost lesser. Our unique two-sided approach to 15-minute rapid charging makes EVs last 3 times longer and cost 30% less than conventional EVs. We’re excited to scale this across India, starting with Delhi-NCR, Mumbai, Hyderabad, Chennai and Ahmedabad!”

In the last 3 months, Exponent claimed to have completed over 25,000 rapid charging sessions, covering over 10,00,000 kms with 200+ EVs powered by the exponent on the road in Bengaluru.

The company is looking to expand its operations in five more cities - Delhi NCR, Mumbai, Hyderabad, Chennai and Ahmedabad by the end of FY24 and is targeting to deploy 1,000 e^pumps and 25,000 EVs powered by Exponent by 2025. 

Also Read:

• SBICAP Ventures-backed Neev II Fund invests in agritech startup Nutrifresh