A new lithium-ion battery design created by a team of engineers at Penn State University in the US could revolutionise electric vehicle technology as it claims to dramatically cut down recharge times and increase battery life – both issues faced commonly by EV owners.
Although current fast-charge technology is known to speed up the process of degredation in lithium-ion battery cells, this new method is claimed by lead engineer Xiao-Guang Yang not to produce such damaging effects, despite its potential to deliver 200 miles (321km) of range in an astonishing 10 minutes.
With the new battery design having been tested extensively, the team of engineers appear confident that it can still hold 91.7 percent capacity after 2500 charging cycles – enough to see a single battery pack cover over 800,000km during its lifetime.
In the report, published by the science and technology journal Joule, Yang et al. describe the need for this technology to be developed further as “electric vehicles will only be truly competitive when they can be charged as fast as refilling a gas tank,” with the added context that the US Department of Energy is pushing for extreme fast charging (XFC) technology to be developed for this reason.
The Penn State team’s proposed and tested solution is an asymmetric temperature modulation (ATM) charging method that avoids lithium plating – the key barrier to improving charging times thus far, which is when metallic lithium forms around the anode and and damages the battery when high amounts of electricity are forced in. Cooling during battery charging is also noted as another key factor hampering charge rate increases.
The ATM charging method is claimed to work by charging lithium-ion cells at an increased temperature of 60°C to avoid lithium plating, but only needs to remain at this temperature for 10 minutes as any longer could cause severe solid-electrolyte-interphase growth.
Furthermore, the battery’s gradual, asymmetric discharge temperature is aimed at opening a new path to enhance kinetics and transport during charging, while also having the added benefit of increasing the battery’s lifespan.
It all sounds pretty good – especially when you consider for one, how long it takes to recharge an electric car even with current fast charging technology, and secondly, how rapidly current fast-charge methods degrade batteries – but the catch is that no production electric vehicle can currently withstand a 400kW charging rate despite the push from “governments and companies worldwide” to see such rapid charging stations installed.
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The main hurdles faced here, however, are that these increased temperatures could pose safety risks in hotter climates – potentially as dramatic as battery cells exploding under intense heat – or lithium plating still remaining an issue in colder climates if the batteries are unable to reach the full 60°C required to avoid this issue.
Furthermore, the need for car companies to produce battery packs capable of withstanding such extreme charging rates and increased charging temperatures means this is far from likely to happen overnight, but we wouldn’t be surprised to see the findings of Yang et al. used to further this critical technology to a point where it is as practical as refuelling a petrol car – something that seems to be less far off by the day.