One of the many challenges facing electric vehicle engineers is the fact that temperature variations can have an impact on battery performance. A new “cloak” developed by researchers at the Shanghai Jiao Tong University seeks to help combat inefficiency by keeping parked EVs cooler in the summer and warmer in the winter.
The idea is basically the same as the battery preconditioning that many EVs already do. In these cases, they warm up the battery on cold days while the vehicle is still plugged in. But that takes energy and although it doesn’t affect range, it isn’t exactly free either.
On the other hand, the thermal cloak that was developed by the researchers is entirely passive, per Eurekalert. By simply placing it over a parked vehicle, it can help moderate its temperature, in effect pre-preconditioning the battery.
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“The thermal cloak is like clothes for vehicles, buildings, spacecrafts, or even extraterrestrial habitats to keep cool in summer and warm in winter,” said Kehang Cui, the project’s senior author.
However, what’s really exceptional about the cloak is that it doesn’t just keep the car warm, it also keeps it cool. In testing, the team found that, on a warm sunny day when the cabin of an uncovered vehicle was 122.9 °F (50.5 °C), the temperature of the cabin of a vehicle that used the thermal cloak was as low as 73 °F (22.8 °C). In winter testing, the product also kept a vehicle considerably warmer than the ambient temperature.
To do that, the cloak is made up of two materials: the outside layer is made of thin silica fibers coated in boron nitride that reflect sunlight, while the inside is made of aluminum alloy and traps heat inside.
The team deliberately designed the material to be scalable, and therefore useful in a commercial context. However, it told the Daily Mail that it’s still not clear how much it would cost to make one large enough to cover a car.
