Automotive Engineering - March 2024 - 34

Q&
A
Axial flux e-motor maker progresses toward
mobility, alters cooling design
SAE Media first introduced readers to Infinitum in a 2023
roundup of e-motor developments. The company claims it
made a 50% smaller and lighter axial-flux motor by replacing
all the copper in the stator with printed circuit boards that
have etched copper conductors. The result is higher efficiency
due to the elimination of core losses from eddy current, stator
hysteresis and more.
Senior editor Chris Clonts stopped by Infinitum's booth at the
Consumer Electronics Show in Las Vegas to see how the company
has fared recently. Its strategy was to
start building industrial motors to meet the
world's biggest e-motor market before
moving on to eventually building mobility
solutions. We asked Chief Strategy Officer
Bhavnesh Patel about that and more.
How is the plan going?
We have maxed out our production capacity
on industrial and commercial motors.
We're selling into a lot of data-center
cooling applications, as the data centers
generate a lot of heat [and are under
increasing pressure to be more efficient].
We are also seeing a lot of pump applications
and the investment from Rockwell
Automation is helping us take this into
material handling such as conveyors and
luggage handling. And we're making
progress on power-takeoff applications.
Still working toward mobility, though?
Yes. We have a number of partners that
we are working with on a hybrid marine
application and a truck application as
well. We've come a long way in a year.
Mobility suppliers are starting to explore PCB stators as well.
Are you concerned they'll capture that market before you can?
We're not too concerned on that front. For us, as a startup, we
raised $185 million a couple of months ago [the company's
Series E funding]. We must be able to turn that cash into actual
progress and milestones.
With the PCB stator, I should also mention that there have
been different ways of making this. Our approach is that there
are multiple layers on the stator because every layer has a single
phase or power - phase A, phase B,
phase C - and layering those on top of
each other. Previous approaches that I'm
aware of have had those all on a single
layer. And so, one of the challenges of that
is you have to connect phase A on the first
layer to phase A on the second layer to
phase A on the third layer. Those interconnections,
called vias, are the most unreliable
and the most costly. By eliminating or
reducing significantly the number of interconnects
we have on ours, it makes it a lot
more feasible to scale-up the technology
to make it more commercially viable for
various applications.
Bhavnesh Patel, Infinitum's chief strategy
officer, said the company modified its cooling
tactics after seeing friction losses created by
spraying coolant directly onto the stator.
A rendering of Infinitum's Aircore Mobility Motor,
which the company says is good for mobility,
marine, construction and agricultural uses due to
its efficiency and modular design.
34 March 2024
" By eliminating or
reducing significantly
the number of
interconnects we have,
it makes it a lot more
feasible to scale-up the
technology to make
it more commercially
viable for various
applications. "
Since last year, has anything changed with
your approach to this kind of e-motor?
In our first approach with the EV motor,
we had a hollow shaft and we sprayed
the stator directly to cool it. We have a
fairly wide air gap between the rotor and
the stator. We didn't expect the fluid to
create frictional losses. In testing, it did
result in some, so we've come up with
other ways of reducing or removing that
heat. Now we rely more on the cooling
jacket, and we've also created fins on the
inside that move air, which we're able to
push over the stator and get the heat
absorbed into the housing.
Are there any other improvements on
the horizon?
We're talking to a lot of the automotive
companies. One of the concerns with all
motors is supply-chain risks. Something
like 70% of motor magnets come from
the same place. So, we've developed an
approach that dramatically reduces the
amount of rare earth magnets. We're not
public with those details yet.
AUTOMOTIVE ENGINEERING
FROM TOP: SAE/CHRIS CLONTS; INFINITUM
Automotive Engineering - March 2024

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