22 highlights
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Exponent Energy—founded by Vinayak and Sanjay Byalal Jagannath, both former executives at electric scooter maker Ather—came out of stealth mode to publicly launch three weeks ago. Its pitch sparked attention almost immediately: charge an EV from 0% to 100% in 15 minutes flat.
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The other big one is range anxiety, or owners’ concern about how far they can go on a single charge, but manufacturers globally have largely solved the issue with advances in vehicle design and battery capacity.
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The one big downside, though, is that lithium-ion batteries wear out with every charge and discharge cycle. The lifetime of a lithium-ion battery is measured in terms of the number of cycles before it has lost enough of its capacity to be unreliable, in the order of 1,000 or 2,000 cycles.
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And with conventional methods of fast-charging these batteries, the result is that the battery wears out even faster.
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So if you are doing rapid charging, the degradation of batteries is higher. This is because whatever you do, there is thermal loss, so batteries heat up, they expand. It is compounded by the fact that in India the batteries are operating in higher temperature conditions.
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The impact of the occasional rapid charge on a passenger vehicle, those meant mainly for urban use at least, is small enough not to bother the manufacturer or the user.
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But for commercial vehicles specifically, there’s an added complication in the form of long operating cycles. Typically up to 14 hours every day. This means a lot of rapid charging cycles are needed to ensure that the vehicle is in continued operation.
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In this context, Exponent is promising a 15-minute charge to full regardless of the battery capacity, with a guaranteed lifetime of 3,000 cycles—which is actually higher than what most EV manufacturers cover—and the ability to operate and charge in this fashion even at 50 degrees Celsius.
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“In layman’s terms, the major issue is that batteries and chargers do not speak to each other—rather, they communicate only at a very superficial level,”
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The company’s tech revolves around carefully managing the impedance within the cells that form the battery—or what it refers to as “chaos” in its explanation for the layperson. Without getting deep into physics, impedance is mostly a characteristic of the internal resistance within a cell.
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One approach, used by Israel-based company StoreDot, is to experiment with and modify the chemistry of the cell—StoreDot does this with a mix of nanomaterials, polymers and additives to the electrolyte in its lithium-ion cells. The Israeli startup boasts that its batteries can charge to full in a mere 5 minutes.
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The system uses a technique known as pulse charging—as the impedance or internal resistance changes, it adjusts the current being delivered to a cell; by constantly modulating the current, the system manages to prevent impedance from building up, which means that it can charge up the battery faster.
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Different cells might be at different voltages or charge levels, which causes an imbalance while charging; Exponent’s BMS is what is known as a balancing BMS, where it adapts the power supply for individual cells while charging, making sure the load is distributed evenly throughout.
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While the company initially intended to source existing BMSes from suppliers and pair them with its algorithms, it found that none of the commercially available ones could deliver the kind of fine-grained sensors and monitoring needed.
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GBT is a charging standard adopted widely in China, and also used in India; apart from its proprietary connector, Exponent Energy’s charging stations will offer standard GBT and CCS connectors, or “guns”, to charge any EV that doesn’t have one of the company’s own battery packs.
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The commercial vehicles industry has much longer product cycles than in passenger vehicles; additionally, going electric has significant unsolved challenges in terms of technology, design and ecosystems when it comes to heavier trucks and lorries. At the higher end, the weight of the battery becomes a big drag on the carrying capacity of cargo vehicles, and while rapid charging could help with that, this would in turn require a pan-India network to be viable.
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The other big set of operational challenges will lie with maintaining the charger network.
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Getting the locations and the network right will also be vital, because (a) drivers can’t afford to go too much out of their way, and (b) the flow of traffic at a charging station could potentially affect downtime more than the actual charging time.
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The idea to start Exponent Energy, he adds, actually came while he was at Ather, sometime in 2018 or 2019, and other manufacturers would approach the company to see if they could license its charging technology. But since Ather, much like a Tesla in cars, had vertically integrated its entire technology stack, from vehicle design and battery to software and charging networks, it wasn’t flexible enough to be easily sold to other companies.
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Exponent Energy also plans to supply OEMs and end-users with apps and a platform that gives them a view of the charging network and helps automate route planning and management to minimize downtime.
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And here, Vinayak claims that the charging station has been carefully designed and built for Indian environments—read: large voltage and power fluctuations—a lesson from the founders’ Ather days, where the scooter maker found that standard parts from overseas suppliers made for chargers that died in India.
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Large corporations in the power industry are eyeing the sector, with Tata Power, for instance, offering a range of charging solutions.