TECH INSIDER | RIVIAN
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those for some time. We were also able to do
hot and cold tests.”
“The worst thing to do when you’re
developing a car for production is to have an
unreliable powertrain,” adds Mark Vinnels,
executive director of engineering and programs.
“It will delay the whole program, so we try to
keep everything that propels the vehicle at least
one phase ahead. That way, when we start
adding the bodies and interiors and we start
crashing these vehicles, we have something
reliable and robust.”
Battery options
Rivian will assemble its own battery packs. They
will be available in 105, 135 or 180kWh variants
and are comprised of off-the-shelf, 2170 Li-ion
cylindrical cells. No suppliers have been named.
“The 2170 cell is a really nice compromise,”
says Sanderson, “the best of the current
technologies. It provides robustness, the
chemistry is stable and there are different
manufacturers doing that size, so we could
have multiple suppliers if we wanted.”
He won’t rule out future upgrades if solidstate
or other new battery technologies were to
go mainstream, however.
“We are mindful of the fact that there are a lot
of technologies on the brink or trying to breach,
and we’re not excluding ourselves from
those,” Sanderson expands. “In the
current platform, cylindrical cells
provide the optimal volumetric
and gravimetric efficiency,
power and storage on the
vehicle today and will
do so for the majority of
its life. But the moment it looks like we can draw in new
technologies that will be better, we’ll start to bring them into
our platform. Luckily the skateboard design makes it quite
easy to adopt new technologies.
“Energy storage solutions are changing quickly,” he
continues. “I suspect that at some point in the future,
something like hydrogen might take over as the energy
storage solution, or at least part of it. We will follow that
and many other solutions that appear on the market.”
Pack development
Back in the present, the power bank and environmental
chamber at the battery and controls development center in
Irvine, California, where Sanderson is based, have enabled the
team to focus on pack health over time. Particular attention has
been paid to thermal management, with some IP-protected
heating and cooling technology to keep the pack within a 5°C
optimal operating range. The lab tests were then validated by
testing the pack on a vehicle in 43°C (110°F) heat.
“Turns out that we sized the cooling system pretty well
and not much had to be modified,” reports Sanderson, who,
like Vinnels, joined Rivian from McLaren.
The battery management system is one of nine key
platform ECUs that have been developed in-house at Rivian.
A Hardware-in-the-Loop environment in Irvine enables the
engineers to test the thermal management module, the
battery management system and the vehicle dynamics
module, all of which have very similar I/O requirements.
Protecting the pack in the event of an impact has been
another early development focus for the Rivian vehicles.
The crash safety demands of world markets play a role,
but so does the expectation that Rivians will be heavily
used off-road.
Extruded aluminum sections protect the pack from side
impacts and a ballistic shield protects the base of the pack
from impact intrusion from underneath the car. According
to Sanderson, “Ballistics experts helped us develop
a good solution that doesn’t weigh a ton or cost too
much. It’s a mixture of aramids and
carbon, a balance of weight,
cost and efficiency.”
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10 // July 2019 // www.electrichybridvehicletechnology.com
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1. The Rivian platform was
under development for 18
months before being
unveiled in LA last
December
2. Components are
rigorously tested in
a controlled environment
3. Rivian’s dedicated
battery packs will be
available in 105, 135 or
180kWh variants
4. Batteries are tested
and compared alongside
one another, using
a high-voltage battery
test system
5. Without the bodywork
it’s clear to see why the
Rivian platform has been
nicknamed the skateboard
/www.electrichybridvehicletechnology.com