Automotive

High-tech car cover could protect EVs from changes in temperature

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A Janus-cloak-covered EV (left) gets tested alongside an uncovered counterpart
Huaxu Qiao
A closer view of the "phononic metafabric" that makes up the cloak
Huaxu Qiao
A Janus-cloak-covered EV (left) gets tested alongside an uncovered counterpart
Huaxu Qiao

Large fluctuations in outdoor temperatures can shorten the lifespan of the batteries used in electric cars – if those cars are parked outside, that is. An experimental new car-cloak could help minimize such damage, by damping changes in temperature.

The Janus thermal cloak, which is used like a regular car cover, is being developed by a team at Shanghai Jiao Tong University.

It takes its name from the ancient Roman two-faced god Janus. The cloak's two "faces" consist of an outer layer that reflects solar heat back out into the atmosphere, along with an inner layer that reflects residual car-heat back into the vehicle.

The outer layer incorporates thin silica fibers coated in flakes of hexagonal boron nitride, which is a graphite-related ceramic that boosts solar reflectivity. Those fibers are braided and woven into a base fabric, which is bonded to the aluminum-alloy inner layer.

A closer view of the "phononic metafabric" that makes up the cloak
Huaxu Qiao

In outdoor tests conducted in Shanghai, a cloak-covered electric car stayed a total of 7.8 °C (14 ºF) cooler than the outdoor daytime temperature. At midnight, after the ambient temperature had dropped considerably, the covered car stayed 6.8 °C (12.2 ºF) warmer than the outdoor temperature.

The cloak was designed with commercial-scale production in mind, as all of the materials are claimed to be inexpensive, lightweight, durable and – as an added bonus – fire-retardant.

A paper on the research, which is being led by Prof. Kehang Cui, was recently published in the journal Device.

Source: Cell Press via EurekAlert

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5 comments
vince
Better to make car wraps double layered with sewn together in 6 inch strips. Then hooked to a high volume blower simikar to those used on bounce houses. Then if it hails you simply flip switch to blow up your car "matress" and hail bounces off without damaging car. Tried it and it works great even at softball sized haill.
P51d007
Unless it is 30 below zero (F), my gas powered car starts every time, doesn't need a blanket and bedtime story like an EV.
Wavmakr
Another reason not to go electric.............
Bob Flint
I like Vince's idea, double as a hail protector, now add some soft solar panels to capture the free energy, and cool/heat as needed.
A-A-Ron
If you cover a car in insulation, it insulates the car...shocking discovery. So if you drive your car to work during the day (as most do) then you have to bring this cover with you. Wonder where you fold it up and fit it in the teeny smart car pictured.