Car batteries with tiny heaters could charge in just 11 minutes

A self-heating lithium-ion battery can charge to 70 per cent in just 11 minutes. The design could allow electric cars to be “refuelled” nearly as fast as petrol ones.

We already knew that heating lithium-ion batteries enables them to be charged faster, but it can cause damage and even fires.

Now, Brian McCarthy at US firm EC Power Group and his colleagues have come up with a design that heats up safely, so an electric car could be charged enough in just 11 minutes to travel about 320 kilometres (200 miles) – something that would take around 45 minutes using existing fast-charging technology.

Fast-charging generally involves thinner or less-dense cathodes and anodes – the positive and negative electrodes of the battery – because it is easier to push lithium ions across a shorter distance during charging, but this limits the battery’s capacity.

McCarthy’s team instead used stacks of anodes and cathodes, interspersed with heaters around a tenth of the thickness of a sheet of paper, to enable a higher energy density as well as fast charging.

In tests, the researchers heated and charged a 265 watt-hour battery to 70 per cent in 11 minutes at 65°C (149°F), and showed that it could accept the equivalent of about 320 kilometres of range – for a higher capacity version of the battery suitable for a car – for more than 2900 charges. 

It is recommended that electric car batteries are charged to no more than 80 per cent for general use to extend their life.

McCarthy says the battery design could help make electric cars more affordable and practical.

“If you could produce battery packs that were faster-charging, and so let you do long-distance trips in comparable time to having one giant battery, you could imagine auto-makers making maybe three or two battery packs with the same amount of materials,” he says. “So then you get more electric vehicles into the system sooner.”