A novel energy-free temperature control system is set to spark a new breed of ultra-efficient electric buses, cars, trucks and even ships.
Heat pipe technology is shown to improve a battery's performance, safety, life and charging times far better and more affordably than typical battery cooling. Developed by Brunel University London and Flint Engineering Limited, the system was tested on a hybrid diesel electric bus battery with Vantage Power Technology, which built the world's first retrofitted hybrid diesel electric buses. For more information see the IDTechEx report on Electric Vehicles 2020-2030.
Results in the International Journal of Thermofluids show the Iso Mat™ heat mat flat pipe technology overtakes conventional battery cooling in a string of tests. It signals a tipping point for electric vehicles.
"Intelligent thermal management means the battery performs better, you get more out of it, it extends the range and makes charging faster," said Brunel's Professor Hussam Jouhara. "It improves functioning throughout."
Found also in computers and mobile phones, rechargeable lithium-ion batteries are in almost every electric vehicle on the road. But if charged or discharged quickly, their inside temperature can get hotter than the makers specify and can lead to fire. But fast charging and discharging offers better performance and longer life, provided batteries are kept cooler and inside manufacturer's set temperatures,
Iso Mat™ technology shifts heat away from the battery, without having to pump fluid through the system to a condenser. This uses the evaporation/condensing cycle of traditional heat pipes but in a new isothermal way. Unlike fluid cooler systems, it keeps working the entire journey and has been tested at 90˚ angles, so very steep hills are no problem.
"What we propose is a system that absorbs the heat in an efficient, uniform way, to keep the battery pack running within the manufacturer-recommended temperature," said Professor Jouhara. "And that actually is lower than manufacturers thought possible using conventional methods. So the heat mat flat pipe system is more efficient, lighter and we can design it according to whatever space is available - to fit cars, buses, trucks and ships too."
With work underway to test a full-scale battery pack, the next step is to take the technology to manufacture. It may be only months until heat pipe cooled batteries are powering buses driving people to work.
"Manufacturing processes are being developed with the support of some of the UK's leading technical support organisations," said Stephen Lester of Flint Engineering. "We are designing the highest levels of reliability and durability into a product that will be supplied at a price that is considerably lower than existing cooling systems can achieve."
Find the full study, Investigation, development and experimental analyses of a heat pipe based battery thermal management system, in the International Journal of Thermofluids.
Source and top image: Brunel University London