NASA Research Points To Drastically Reduced EV Charging Times

[advrider]

Two of the biggest challenges facing widespread electric vehicle adoption are range, and the time it takes to recharge. In order for the general public to embrace using electrons instead of fossil fuels, EVs will need to match the range and quick fill-up times of internal combustion engine vehicles. While the range of some of the more expensive EVs have begun to match those of ICE vehicles, the charging times still leave something to be desired.

However, NASA has recently seen breakthroughs in their research that may give EVs the ability to charge in five minutes or less, rather than the 20 to 40 minutes that the faster charging models currently on the market require.

The key to the fast-charging equation is cooling – in order to flow lots of amps to charge a battery in a very short time, a significant amount of heat must be dissipated, especially from the charging cables. NASA-funded research at Purdue University that will aid in future space missions may also be the answer to keeping EV charging systems cool enough to deliver the five-minute charge consumers want. Up until now, the equipment required to achieve the level of cooling necessary would render the charging cable too heavy, bulky, and inconvenient for consumers to use.

Image: NASA Glenn Research Center

The Flow Boiling and Condensation Experiment (FBCE) was created to validate a model for something called flow boiling critical heat flux (CHF), which will allow for the development of an “integrated two-phase flow boiling and condensation facility” for the International Space Station. Experiments conducted using the facility in microgravity will support the development of boilers and heat exchangers for use in microgravity and partial gravity that are significantly smaller and lighter, and the technology can also apply to earth-bound cooling systems.

The concept, in a nutshell, consists of a flow channel full of liquid coolant. As the channel is heated, the liquid next to the walls of the channel boils, creating small bubbles. The bubbles leave the walls of the channel at a high frequency, drawing liquid from the middle of the channel to the walls, which transfers heat both because the liquid from the middle of the channel is cooler, and also because of the change in phase from liquid to gas (the boiling). Heat transfer performance is increased further by “subcooling” (cooling it well below the boiling point) the liquid before it enters the channel. Called “subcooled flow boiling”, the process is said to transfer heat considerably better than current techniques.

Image: Purdue University/Jared Pike

With this technology in place, Purdue produced a charging cable that is constructed compact and light enough for consumer use, and can deliver up to 2,400 amperes, while removing up to 24.22 kilowatts of heat. The power that Purdue’s cable provided is well above the 1,400 amperes required for five minute charging.

With technology such as this on the horizon, one more hurdle to getting more EVs on the road may be solved. There are still many to go, such as cost, implementing the infrastructure on a widespread scale, ensuring electricity can be provided in a consistent and environmentally friendly manner, not to mention the issues regarding battery manufacture and disposal, but it can only be a matter of time before science and engineering leap those hurdles as well.

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