Electric vehicle (EV) companies solved the mileage problem a few years ago, but are yet to figure how to recharge these vehicles as fast as we refuel petrol vehicles.
A Bengaluru-based startup, Exponent Energy, believes it has an answer to this problem. Exponent Energy claims its technology can charge any commercial EV battery from zero to 100 percent in a mere 5-15 minutes, making it similar to refueling a petrol vehicle.
According to the startup's co-founder, Arun Vinayak, who was the chief product officer at EV startup Ather Energy, the technology also does not require special batteries or battery chemistry, and is compatible with regular Lithium-Ion and other common battery types used today. Exponent will work with both EV makers and companies running charge point operators (CPOs) to deploy its solution all over India, says Vinayak, who was earlier the chief product officer (CPO) of EV startup Ather Energy.
Vinayak co-founded Exponent with the help of Sanjay Byalal Jagannath who was the Hardware Strategy Sourcing and Cell Strategy Lead at Ather.
“It’s fair to say that EVs are better vehicles, but they’ve broadly remained shackled because of the energy problem,” says Vinayak. According to him, delivery of power from the charger to a battery is a problem that no one’s focusing on.
“On the one side, you have charge point operators buying charging stations and putting it up on grids, while on the other you have OEMs who are focusing on building batteries and vehicles along with that. Which is why vehicles drive better and you have people setting up charging stations, but they don’t seem to work together. Which is why you see vehicles that take 8 hours (or more) to charge up, and batteries that last only 1000 cycles,” he explains.
To work around this issue, Exponent Energy has developed the so-called flexible energy stack, which is a combination of hardware and software meant to enhance charging speeds. The company has devised a proprietary battery management system (BMS), which is a common term for electronic systems used to monitor and manage power stored and supplied to an EV. Simply put, the BMS monitors how a battery pack is being charged, what the health of different cells in the pack are, etc.
According to Vinayak, almost 50% of Exponent’s technology is software, which controls how seamlessly and accurately energy flows from the grid to the charger and then the battery. “For us, a battery involves buying cells that are commercially available, slapping on our BMS, having the right thermal management for the vehicle, which lets us rapid-charge commercially available cells,” Vinayak explains.
He claims that Exponent’s BMS is 10 times more accurate than any BMS on the market today. An EV battery includes thousands of cells inside, which may be at different levels of charge when the vehicle is connected to the power source. Exponent’s BMS understands what state the entire battery is in, including its health. It also creates customized charging profiles for the batteries, which modulates the current flowing to it while charging.
The company will also provide a 3000-charge cycle warranty for batteries charged with its technology. Vinayak says his startup has tested a battery for 800 cycles, with each cycle being a 15-minute charge followed by a one-hour discharge and recorded less than 3.5% degradation in battery capacity. Lithium-Ion batteries lose some of their total capacity each time we charge it.
As an industry standard, the EV industry considers a battery a failure if there’s more than 20% degradation after 1000 cycles. One cycle, in general terms, is a battery being charged from zero to 100 percent.
“Fundamentally, rapid charging is not new. It has been around since 2008. But you had to use cell chemistries like Lithium Titanate Oxide (LTOs) batteries, which are three times heavier and five times more expensive, etc. Which makes it infeasible from a commercialisation point of view,” Vinayak points out. “We don’t think rapid charging is new, but the fact that people approach it only from a cell chemistry point of view limits how efficiently we can solve this problem,” he adds.
That said, the EV sector is experimenting with cheaper options too.
“I think the alternative to fast charging right now is battery swapping, which takes no time,” says Kavan Mukhtyar, Partner and Leader, Automotive, PwC India. “A lot of companies are trying that route, especially for two-wheelers, because in the Indian environment the perception is that a super or a rapid-charger will be a pretty high investment, while swapping may be a more economical option provided one can solve pilferage issues,” he said, talking about the current charging ecosystem in the country.
“There are others who are also trying rapid chargers and all, but the whole point is what’s the equation in terms of how many minutes it would take and what’s the investment. Currently, the investment tends to be on the higher side in most cases,” Mukhtyar says. “There are people who are trying it out for sure, but I don’t think there’s anything that has been successful at scale (so far),” he adds.
At the moment, any fast-charging technology, even in smartphones, requires an adapter that can charge batteries fast and a battery that can charge faster, or both. Exponent has two products, an e-pack and an e-pump, which are basically battery packs and charging stations built using Exponent’s technology. Companies can continue sourcing cells from their current suppliers and ask Exponent to add its own technology on top. Most OEMs today work with battery manufacturers who source cells from China and build battery packs.
Nevertheless, there are investors who believe in the Exponent model. The company has raised a pre-seed round of over Rs. 7 crore from investors like AdvantEdge, 3one4 Capital and YourNest. According to Vinayak, the company will be doing a seed round in the next couple of months to take the technology to market. He concludes that Exponent is focused on working with commercial EV companies right now and is working with some last mile cargo companies already.
