Auto covers traditionally keep cars dust-free and dry, when standing outside or in storage. Their manufacturers thoughtfully add breather pockets to prevent the accumulation of any heat. However, scientists at Shanghai Jiao Tong University, China turned this theory on its head on July 11, 2023. That was when they proposed passive electric car covers to keep electric car batteries warmer in winter, and cooler in summer.
Potential Benefits of Passive Electric Car Covers
By now we know that lithium-ion batteries perform best within a range of temperatures that suit humans most. Do you suppose this is to be expected, as humans invented them? Answers on a virtual postcard please. Setting that aside, here are the main benefits of the passive electric car covers the scientists from Shanghai Jiao Tong University, China claim, and we quote:
- Scalable, passive, all-season temperature regulation through photon recycling.
- Daytime sub-ambient passive cooling by 8.0°C in summer.
- Nighttime supra-ambient passive warming by 6.8°C in winter.
- Fire retardant, reliable in-thermal, cryogenic, vibration, and corrosive environments.
As the researchers explain in their report we link to below, thermal management is essential for many devices we use outdoors. Here we think of vehicles, energy storage stations, and spacecraft for that matter. However, dynamic thermal management of temperature may consume a heavy energy load.
These Thermal Car Covers Consume No Dynamic Energy!
The term ‘passive cloak’ is the key to this breakthrough. These particular passive electric car covers comprise two layers of different material:
- The outer layer is a silica product enhanced with flakes of boron nitride to reflect solar energy away.
- While the inner layer comprises an aluminum alloy sheet that prevents the batteries cooling.
“The cloak works basically the same way the earth cools down, through radiative cooling” the researchers told Eurek Alert. “The earth is covered by the atmosphere, and the atmosphere is transparent to a certain range of electromagnetic energy we radiate.
“While this process is desirable in the summer, it would make the car colder during winter months. You have to develop something that can turn on and off by itself, without external energy input, and that’s the challenge …”
More Information
Wider Temperature Range for Lithium Sulfur
Lithium Battery Sub-Zero Temperature Tweak
Preview Image: Earth’s Energy Budget
