26 September/October 2023 | E-Mobility Engineering can easily tailor the power delivery via the motor control software if needed.” CALLUM and Nyobolt anticipate that the EV will begin testing in November this year to prove out the long-term charging and life cycle capabilities of the car in real-world conditions. Battery materials Given the work involved in creating its anode material, Nyobolt declines to reveal its exact formula. However, it has provided a demonstration of its modules’ ability to charge in 6 minutes at a rate of 12C using COTS recharging and monitoring equipment. The company has also been granted a patent for an electrode with a niobiumcontaining metal oxide surface. It says it has considerable capabilities in high C-rate charging and discharging across a wide range of temperatures, as well as optimal capacity retention during intensive cycling at temperature extremes, particularly when compared with lithium-ion cells with graphite electrodes (although that does not refer to the specifics of the anode). However, Dr Shivareddy cautions against placing too much emphasis on a ‘secret sauce’. “Looking at one battery material – be it an anode, a cathode or any other component of a chemistry – never gives you the full picture. There are so many nuances in each component, so knowing all about one part doesn’t help you in knowing what’s possible at the system level. “Certainly, over the past 6-7 years we have focused more on the anode material side, but there also has to be an interplay with cathode materials, the electrode winding, the electrolyte separator and other structures. Together they need to optimise how much energy you can store and how quickly you can move it in and out of the cell via lithium ions.” That has entailed close consultation with cathode materials companies, metals suppliers and mining companies exploring new sources of graphite and other carbon-based anode materials outside China. The aim is to examine the scientific, cost and sustainability issues of different material combinations in different cell designs. Dr Shivareddy is reluctant to think of Nyobolt’s proprietary anode as a miracle invention, instead emphasising that the paradigm of ‘energy density above all else’ has simply held such sway for so long in attempts at battery commercialisation that efforts to prioritise power density instead have been stymied through a lack of impetus or support. “Requirements define constraints, and for a long time maximising mAh/g was the most important requirement,” Dr Shivareddy says. “Throughout that time, going for power density wasn’t always possible, especially as the consumer space was rife with USBtype connectors that had limitations on power throughput, or they used really big chargers to provide compatible current levels and so didn’t need cells capable of high C-rates. “Factors like that really influence and limit the range of research into alternative battery chemistries. We were effectively the first to spend so many years putting the scale of resources we did into maximising the rate capability and charge-discharge capability within a cost constraint that would keep the price acceptable to the market. In fact, the only other space we’ve ever seen where power density was made so important has been in motorsport, particularly Formula One.” The kinetic energy recovery system came into effect in Formula One around 2007-8, and this required that batteries in the racecars could accept extremely high inputs of power from regenerative braking. That in turn spurred significant research into battery material combinations that could achieve new heights in power density, but without skimping on energy density. “Of course, those batteries only needed to last one season, so you could push the limits and have cycle lifespans of just 100-200 cycles, and they didn’t need to be designed for bulk manufacture in a way that would bring their prices down,” Dr Shivareddy says. “Nor did they emphasise researching their charging capabilities as much as their discharging, and there’s a lot of Dossier | Nyobolt EV Nyobolt has used mainly COTS equipment for testing, simulation, analysis and data recording (Courtesy of Elan PR)
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