Researchers have found a way to slash recharge times – goodbye, splash and dash; hello zap and zip
Here’s a fun experiment. Put anything vaguely positive about electric cars on the internet, then wait. Sure as night follows day and Audi drivers follow too close on the motorway, someone will pipe up and say something along the lines of ‘When I can fill up in five minutes like I do currently, I’ll consider an electric car’.
But let’s assume for a moment that a five-minute fill-up is actually the point where the inevitable commenter will put their money where their mouth is. In that case, we have some good news – American researchers have worked out a way to charge a lithium-ion EV battery from nearly dead to 90 per cent in 10 minutes, without causing any of the damage that would usually occur during such an endeavour. And, crucially, without relying on future developments in battery technology, such as solid-state electrolytes.
Instead, researchers have used machine learning, training an AI to predict how and when EV batteries would eventually fail and then find the optimal way to rapidly charge without causing the damage that would lead to those failures. Needless to say, it required reams of data from various EVs – each company has its own way of doing things, after all – and the modern marvel that is artificial intelligence. But when the team tested its results on real batteries and charged a near-flat battery to 90 per cent in 10 minutes, we’d say the faff was worth it.
But why can’t we just up the power on a regular charger to get the same result? Well, buckle up, because this involves some science.
Charging an EV battery too quickly can result in lithium being electroplated onto the anode, rather than filing itself away in the graphite structure in a process known as intercalation. That intercalation bit is the key to lithium-ion batteries working at all, so any deviation from the norm is obviously going to have serious effects. Losing lithium ions to anode plating means losing battery capacity, while enough plated lithium can cause short circuits and complete battery failure.
That’s why we’ve seen companies like Porsche and Hyundai move to 800-volt architecture (more volts mean less current for a given wattage, which means less heat generated through resistance and less chance for damage), and why chargers have to slow down when the battery is close to fully charged – or discharged. But by optimising the way vehicles are charged on an individual basis – rather than the ‘better safe than sorry’ methods we currently use – a huge hurdle to EV ownership is effectively removed, without any change to the battery construction or chemistry.
At least, none yet. The researchers want to use what they (and the machine) have learned to design new batteries optimised for fast charging, as well as battery control units that can tell charging stations how to recharge as quickly as possible without damaging the battery. Obviously, there are one or two kinks to iron out – getting manufacturers on board with the idea, for one – but if nothing else, it’ll be a fun experiment.