Switching to an electric vehicle requires is adapting to longer ‘refuelling’ times. Besides the fact that places to recharge are not as common as petrol stations, the process to recharge a battery pack is significantly longer than pumping in liquid fuel.
So apart from extending the range that can be obtained from a fully charged battery pack (which can now go beyond 1,000 kms), shortening the time spent at the charging station is also something which battery and EV makers are working hard on.
Recently, Polestar and fast-charging battery pioneer StoreDot successfully demonstrated the implementation of StoreDot’s Extreme Fast Charging (XFC) technology for the first time, recharging a specially commissioned 77 kWh the battery pack in a Polestar 5 prototype from 10% – 80% in just 10 minutes. This could add 320 kms of range to a mid-sized EV. An EV driver could therefore stop for just 5 minutes at 50% and continue their journey with over 80%.
This world-first demonstration was done using silicon-dominant cells in a driveable vehicle – rather than individual cells in a laboratory environment. Conducted by Polestar and StoreDot battery engineers, the recharge test was designed to demonstrate proof-of-concept for XFC battery technology that could be applied to future Polestar vehicles.
It should, however, be noted that the speed was also related to using a very high DC power supply. The charging rate started at 310 kW and rose to a peak in excess of 370 kW at the end of charging. Being compatible with such a high charging rate is currently not common in EVs and while there are charging stations with up to 350 kW, they are not necessarily common yet.
StoreDot’s revolutionary XFC technology utilises silicon-dominant cells with an energy density on par with state-of-the-art NMC (lithium-ion Nickel Manganese Cobalt) cells.
The experimental XFC battery’s modules have a structural function which improves mechanical properties and cooling ability while maintaining or reducing weight levels, with high recyclability and serviceability also paramount in the design of the pack. Therefore it also does not require specialist cooling systems in the vehicle.
In today’s commercial EV batteries, fast charging rates can vary greatly depending on the battery’s state of charge (SOC), sometimes dropping significantly as SOC increases. During this test, Polestar saw charging speed rise from 310 kW at 10% SOC to over 370 kW at 80% SOC, proving the technology’s steady charging rate with no significant change in charging speed or efficiency whenever a driver decides to stop within this wide state-of-charge range.
“Time is one of life’s greatest luxuries, and as a manufacturer of luxury electric performance cars, we need to take the next step to address one of the biggest barriers to EV ownership – charging anxiety. With this new technology, on longer journeys when drivers do stop, they’ll be able to spend less time charging and be back on the road faster than before. In fact, that stop time will be more akin to what they experience with a petrol car today,” said Thomas Ingenlath, Polestar CEO.