Fast-charging of electric vehicles is seen as key to their take-up, so motorists can stop at a service station and fully charge their car in the time it takes to get a coffee and use the toilet – taking no longer than a conventional break. But rapid charging of lithium-ion batteries can degrade the batteries, researchers at Penn State University in the US say. This is because the flow of lithium particles known as ions from one electrode to another to charge the unit and hold the energy ready for use does not happen smoothly with rapid charging at lower temperatures.
However, they have now found that if the batteries could heat to 60°C for just 10 minutes and then rapidly cool again to ambient temperatures, lithium spikes would not form and heat damage would be avoided. The battery design they have come up with is self-heating, using a thin nickel foil which creates an electrical circuit that heats in less than 30 seconds to warm the inside of the battery. The rapid cooling that would be needed after the battery is charged would be done using the cooling system designed into the car.
Their study, published in the journal Joule, showed they could fully charge an electrical vehicle in 10 minutes.