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IPFS News Link • Transportation

Microwave Energy Could Fix The Biggest Problem Facing EVs

•, By Alex Kimani

The frigid weather had another unintended consequence: it exposed just how vulnerable electric vehicles are to low temperatures with many EV drivers being left stranded after their vehicles prematurely run out of juice.

According to the American Automobile Association (AAA), an EV can lose as much as 12% of its range when temperatures drop to 20 degrees, and as much as 41% if you turn on the cabin heater. In other words, for every 100 miles of combined urban/highway driving at 20°F temperatures, the range of an EV drops to 59 miles. Range loss due to low temperatures varies according to the EV model, with a BMW 13s averaging 20.4% reduction in range at 21 F in combined HVAC on/off scenarios; Tesla Model S 75D loses 11.3% while a Volkswagen 3-golf sees a 6.9% deterioration. EV batteries work less efficiently in cold conditions while charging times can double or even triple for older EVs. 

Luckily, a handy solution could be around the corner: Researchers from the University of Birmingham are working on an energy storage system that combines microwave energy and a chemical heat pump to produce heating or cooling on demand. 

Dubbed e-Thermal bank, the system is designed as a secondary energy source for EVs that can harness electricity to drive a high-density (1600Wh/Kg) thermochemical-based system. The thermal bank is  'charged' at the EV charging station by using microwave energy to dissociate a solid-vapor working pair.

During discharging, the process is reversed by feeding the vapor into a reactor to generate heat, while the opposite phase uses an evaporator to generate cooling simultaneously. In effect, this charging process stores microwave energy inside the car, in the e-Thermal bank.

"We aimed to offload these thermal management tasks to a microwave driven process. Microwave is a fast heating method, because microwaves penetrate uniformly through materials and so deliver energy evenly into the body of the material," Professor Yongliang Li, who is chair in Thermal Energy Engineering in Birmingham's School of Chemical Engineering, said, as reported by