Automotive Engineering - December 2022 - BET5

Graphite
Chemical
Reaction
Atomic Ratio
Cravimetric
Capacity
Volumetric
Capacity
Swelling
During Charge
Silicon
C6 <> LiC6
Si4 <> Li15Si4
1:6
372
mAh/g
~700
mAh/cc
7%
3.75:1
(23x better)
3,579
mAh/g
~2,100
mAh/cc
300%
Comparison of key properties of graphite
and silicon as they relate to use in batteries.
(Image: Sila Nanotechnologies)
From there, the focus will be on scaling
for high volume. " Large-scale manufacturing
is to be able to process tens of
thousands of tons, so that the [Sinanode]
material can be used in a million, 2 million,
3 million EVs. Now, what is totally
unique about our relationship with GM
and our business model is that the largescale
manufacturing is not going to be
built by OneD, " Pluvinage said. Instead, he
added, OneD will license its process to be
incorporated into existing battery manufacturers'
production process and facility
footprint. All with comparatively low-cost
and high-throughput equipment, he said,
including machines already in use to fabricate
solar cells.
" If you go for example, to China to a
company like Longi, which is the largest
supplier of solar cell in the world, you
see hundreds and hundreds of those
machines. There are suppliers in United
States - we use a supplier in New York
called CVD Equipment Corporation. It is
so efficient that instead of putting the
wafers to make solar cells inside the
machine, in the tube that comprises
those machines, we put the reactor that
we designed, which is the graphite in
which we are going to grow the silicon
nanowires. A single machine, which
costs a few million dollars, can produce
enough anode material for two gigawatt-hours
of anode. "
The Sinanode anode-coating process, says OneD, leverages readily available, cost-efficient
processing machinery. (Image: OneD)
Energy Density, ChargingTime
Upgrades
Although EV consumers will directly
benefit from the reduced cost structure
silicon-infused battery anode material
is claimed to provide, they may be as
pleased with the added EV performance
it promises. OneD and other silicon-anode
developers expect new silicon-intensive
Li-ion batteries to address anxiety
about driving range and also cut
recharging times - both significant
barriers to consumer acceptance.
Israel-based StoreDot,
for example,
said in 2021 in a release that it intends
to have its patented " silicon-dominant
anode " Extreme Fast Charge (XFC) Liion
battery in production " via traditional
certified lithium-ion battery
manufacturing lines in 2024. " StoreDot
also said it reached a framework agreement
with China-based Eve Energy Co.
Ltd. to produce engineering samples of
the XFC battery and to create a venture
for mass production of the XFC.
OneD's Pluvinage said the company
expects its silicon nanowire-infused
graphite anode technology to provide
significant gains over current Li-ion batteries.
" If you look at the mobility of
electrons along nanowires, " he said, " it's
even faster than in graphite. The lithium
ions [the battery's electricity carrier] can
get in and out very easily, because there
is nothing in their way and the radius is
so thin and so small that they get in and
Battery & Electrification Technology, December 2022
out of the silicone very quickly. " The 20
percent silicon and its presence in the
unique structure of nanowires allows a
tripling of the anode's energy density,
Pluvinage said. Increases in charging
speeds and driving range - or reduction
in size of an EV's battery pack - will
depend on an individual battery manufacturer
or automaker's deployment of
the technology, but for recharging times,
StoreDot claims its battery technologies
" will deliver 100 miles in 5 minutes by
2024, 100 miles in 3 [minutes] by 2028
and 100 [miles] in 2 [minutes] within a
decade. "
" If you look at the total market between
now and 2030, we need to reach
for example 40 percent, 50 percent [EV]
market penetration. That means that the
vast majority of the market cannot afford
an EV today, " Pluvinage said. " What
the world needs is an EV that can sell for
less than $30,000, has a range of more
than 300 miles, and can charge from
10 percent to 80 percent in less than
30 minutes. Nobody makes that. That's
why we like GM. Because as [GM CEO]
Mary Barra said, 'Our goal is to make EVs
affordable, and we want to produce millions
of them.' So that's a perfect match
between their goals and our goal. "
This article was written by Bill Visnic,
Editorial Director,
Mobility
For more information,
Media.
visit www.
mobilityengineeringtech.com. 
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