Automotive Engineering - March 2021 - 28

NAWA aims for 5-minute EV charge

NAWA regards its nanostructured electrode
as heralding an EV battery step change.

A new nano-based carbon electrode is key to reducing electric-vehicle charging time.

'Highest' ionic conductivity
A major limitation of incumbent lithium-based battery performance is
the design and material used for the electrode, Boulanger explained.
28 March 2021

Existing powder electrodes have low electrical and thermal conductivity, along with poor mechanical behavior
when discharged and recharged, and can suffer from
safety and life-cycle issues. He said the micro-structures
in today's electrode material make it difficult for ions to
move around, resulting in low ionic conductivity. The
UFCE's patented VACNT design, he claims, combines
the " highest " ionic conductivity, thanks to its 3D fully
accessible nanostructure, with continuous conductors
(the nanotubes) that exhibit optimum electrical and
thermal conductivity. These characteristics eliminate
thermal runaway issues, Boulanger said.
Mechanically, the VACNT serves as a cage, reducing
volume expansion of the electrode and allowing it to
operate under less " stress " than powder electrodes:
" 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. "
This " radically " boosts the battery's ability to deliver
fast charge and discharge rates, he said. NAWA previously demonstrated this in its next-generation ultracapacitors (known as the Ultra-Fast Carbon Battery),
claimed to have " the lowest electrical serial resistance
AUTOMOTIVE ENGINEERING

NAWA

French nanomaterials company has developed a technology
that it claims can significantly increase the storage efficiency
of electric vehicle batteries. NAWA Technologies' Ultra-Fast
Carbon Electrode (UFCE) is a key to bringing EV batterycharging time into parity with gasoline-refueling time, while improving battery life-cycle performance by a factor of up to five, according
to company founder and CTO, Pascal Boulanger.
In an interview with SAE's Automotive Engineering, Pascal
Boulanger said the UFCE technology can help deliver 1,000-km
(620-mi) operating range for mass-market EVs, with a time of five
minutes for an 80% charge. " The uniqueness of the technology is its
3D structure and use of vertically aligned carbon nanotubes
[VACNT], " he noted. Each nanotube is formed from a graphene sheet
that is rolled in a cylindrical shape. The tubes have " 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! " The UFCE technology is compatible with any advanced
battery-cell chemistry, he said.

by Stuart Birch

Automotive Engineering - March 2021

Table of Contents for the Digital Edition of Automotive Engineering - March 2021