Experimental technology developed to cool NASA equipment in space also has a ground-based benefit: reducing EV charging times to five minutes or less.
Using a technique known as “supercooled flow boiling,” this technology could increase the amount of electrical power today’s EV chargers can deliver to cars by improving heat transfer from the charging cables, the US space agency said on Tuesday. That would drastically reduce the time it takes to charge a vehicle.
NASA estimates that a current of at least 1,400 amps would be enough to charge a car in five minutes. To put this in context, modern chargers available to science and industry today only deliver currents up to 520 amps, while most chargers on the consumer market “support currents less than 150 amps”.
A team at Purdue University led by mechanical engineering professor Issam Mudawar and sponsored by NASA’s Department of Biological and Physical Sciences said it achieved 2,400 amperes along a subcooled flow-boil cable, far more than what would be required to produce one Charge electric vehicle in five minutes or less. Note that this was a lab experiment with just the cable: a real world vehicle would need a suitably rated battery and power supply and a cooled cable to achieve this charge in under 5 minutes.
The scientists’ cable design, we were told, could be used “to deliver 4.6 times the current of the fastest available EV chargers on the market today, while removing up to 24.22 kilowatts of heat.” That number of 4.6 comes from taking 2,400 amps and dividing it by the 520 amps of an advanced charger.
Purdue Visiting Assistant Professor of Mechanical Engineering VS Devahdhanush, who worked with Mudawar on the project, said the Purdue team has worked with NASA for more than a decade, during which Mudawar and his group have studied various two-phase fluid flow and heat transfer models , including subcooled flow boiling.
“During that time, we learned a lot about these physical phenomena,” said Devahdhanush The registry.
NASA is certainly interested in the tinkerers’ subcooled flow boiling and applied the technique in their Flow Boiling and Condensation Experiment (FBCE), which ran on the International Space Station last August and was designed to test the technology in a microgravity environment.
In NASA’s FBCE experiments, a series of devices are used to direct non-conductive dielectric fluid into a channel in which superheated devices are mounted. As the devices generate heat, the liquid in the channel heats up and eventually begins to boil. As the liquid boils, bubbles form on the walls and shoot off at high frequency, moving liquid from the cooler side to the hotter side.
A failure of the space station’s FBCE experimental equipment… Images: NASA
“This process efficiently transfers heat by taking advantage of both the liquid’s lower temperature and the resulting liquid-to-vapor phase change,” NASA said, noting that it works even better when the dielectric liquid is cooled well below its boiling point becomes.
How cold liquid can charge electric vehicles quickly
One of the biggest downsides of current EV technology is charging speed: a long drive can add hours while the car is charging – if and when chargers can be found.
The Purdue team proposed adding subcooled flow-through cooking technology to the EV fast-charge cables — not an entirely new design, as liquid-cooled EV charging cables already exist but are limited in their capabilities, NASA said.
“Charging cables for traditional 350-amp fast-charging systems require significant conductors, making the charging cable quite heavy and inconvenient for customers to maneuver,” NASA said. In addition, these chargers can only deliver a fraction of the energy needed to charge an electric vehicle in the same time it takes to fill up the tank.
In 2017, the Purdue team also began working with Ford Motor Company, eventually developing a cable design that premiered late last year that included subcooled flow boiling.
“NASA-FBCE experiments and results have inspired some aspects of our EV cable cooling experiments, particularly by adding to our engineering expertise in this physics,” said Devahdhanush.
Devahdhanush said this fast-charging technology is not yet ready for market launch, and the exact time to market of supercooled flow boiler cables depends on support from government agencies and industry partners willing to invest in the technology.
While Devahdhanush is still in the research phase, Devahdhanush said, “We are currently working with several automotive component manufacturers to further improve and implement this technology.”
Devahdhanush is now Associate Director at Purdue University’s Research Center for Electric Vehicle Charging and Thermal Management, where he, Professor Mudawar and a team are “conducting research and are currently in discussion with multiple entities to complete R&D efforts on multiple components of the EV -Charging process and the EVs themselves.” ®
https://www.theregister.com/2022/10/05/nasa_battery_charging/ EV charging may be possible in under 5 minutes using NASA cooling • The Register