Electric vehicle battery that charges in 10 minutes could end range anxiety
An electric vehicle battery that can give drivers 200 to 300 miles of range from just a 10-minute charge has been developed by engineers at Penn State University in the United States.
The battery could help to alleviate 'range anxiety', the fear that many electric-car drivers have on longer journeys that they will run out of power before reaching their destination, therefore requiring a protracted charging stop.
“We demonstrated that we can charge an electrical vehicle in ten minutes for a 200 to 300 mile range,” said Chao-Yang Wang, who worked on the battery. “And we can do this maintaining 2,500 charging cycles, or the equivalent of half a million miles of travel. Fast charging is the key to enabling widespread introduction of electric vehicles,”
Tesla superchargers can currently charge compatible models to about 50 per cent after 20 minutes, giving drivers about 150 miles of range.
Lithium-ion batteries typically degrade when rapidly charged at ambient temperatures under 10°C due to an interaction between the lithium ions and the carbon anodes known as lithium spikes. This can reduce cell capacity and even cause electrical spikes and unsafe battery conditions.
The researchers had previously developed their battery to charge at 10°C in 15 minutes. Charging at higher temperatures would be more efficient, but long periods of high heat also degrade the batteries.
Wang and his team realised that if the batteries could heat up to 60°C for only 10 minutes and then rapidly cool to ambient temperatures, lithium spikes would not form and heat degradation of the battery would also not occur.
“Taking this battery to the extreme of 60°C is forbidden in the battery arena,” said Wang. “It is too high and considered a danger to the materials and would shorten battery life drastically.”
The rapid cooling of the battery can be accomplished using the cooling system that already exists in the car.
“The 10-minute trend is for the future and is essential for adoption of electric vehicles because it solves the range anxiety problem,” said Wang.
To further help with this, around 2,800 charging stations are due to be built across the US funded by the more than $2bn penalty paid by Volkswagen after admitting to diesel emissions cheating. These charging stations will be in 500 locations.
The self-heating battery uses a thin nickel foil with one end attached to the negative terminal and the other extending outside the cell to create a third terminal. A temperature sensor attached to a switch causes electrons to flow through the nickel foil to complete the circuit. This rapidly heats up the nickel foil through resistance heating and warms the inside of the battery.
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