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A HEADLINE CAUGHT my eye: “Aiming for the 5-minute EV Recharge,” in SAE Automotive Engineering, April 2021.
The Technology Report by Stuart Birch describes nanotech advances from NAWA Technologies, headquartered in Rousset, France, about 25 miles northeast of Marseille. Company founder and Chief Technical Officer Pascal Boulanger told Birch that its Ultra-Fast Carbon Electrode could “help deliver 1000-km (620-mile) operating range for mass-market EVs, with a time of five minutes for an 80-percent charge.”
Both range and especially replenishment time have been limiting factors with EVs, which thus far occupy something like a meager 2 percent of the new-car sales in the U.S. This is despite environmental goals—and political targets—of widespread electrification of transportation in the relatively short term.
Nanotubes to the Rescue. With perhaps a surfeit of initializations, a key to NAWA’s UFCE is the technology of VACNT, Vertically Aligned Carbon Nanotubes. These 3D structures of incredibly tiny diameter are formed from graphene sheets rolled into a cylindrical shape.
Boulanger describes the tubes having “the same aspect ratio [between diameter and length] as a kilometer-long piece of spaghetti, with the electrode being made of a hundred trillion of these tubes.”
What’s more, he said UFCE VACNT is compatible with any advanced battery-cell chemistry.
Electrode Material Limitation. Birch writes, “A major limitation of incumbent lithium-based battery performance is the design and materials used for the electrode.” In a sense, the microstructure of today’s electrode makes it difficult for ions to move around.
VACNT Benefit. Boulanger said, “Put simply, this means the distance an ion needs to move is just a few nanometers through the cell material, instead of micrometers with a plain electrode.”
Birch writes, “Applying NAWA’s technologies to lithium-based cells would improve battery power by a factor of 10 and energy storage by a factor of up to three, Boulanger stated, with battery life cycle enhanced by up to five—and and charging time reduced to minutes instead of hours.”
All around, an EV win-win.
An EV Contrast. Birch notes an inherent contrast between EV and gasoline-fueled vehicles: “EV owners have learned that the more you drive, the faster you discharge the battery. Unlike a tank of gasoline, EV energy consumption is not linear.” However, benefits offered by technologies such as NAWA’s mitigate this inherent EV characteristic.
Fuel-Cell Benefits Too. Birch observes, “Potential applications of NAWA’s UFCE technology extend to hydrogen fuel cell systems. One uses NAWA Cap ultra-capacitors to harvest energy that would otherwise be lost. The UFCE also can serve as an electrode for the fuel cell membrane ‘because VACNT are known to be able to reduce the loading of platinum,’ thus saving cost, Boulanger said.” Platinum requirements have been one of the cost challenges of fuel-cell technology.
“And,” Birch continues, “materials developments by another NAWA Group unit can reduce the weight and improve the strength of the hydrogen carbon-composite storage tank.”
How Soon? Boulanger told Birch “There are various ways of introducing our concept of 3D-electrode to the market.” The easiest would be to grow a very thin layer of VACNT on a copper substrate, rather than carbon-coated copper substrates now used in the battery industry.
This would be superior to today’s technology and could be ready in small volume production in 2021. Full exploitation of 3D electrodes could be in low volumes by early 2023 and reach mass production by 2025.
Just in time to meet economists’ (i.e., non-engineers’) 2019 predictions of “EVs accounting for approximately 10-15 percent of sales in 2025.” ds
© Dennis Simanaitis, SimanaitisSays.com, 2021