Truck & Off-Highway Engineering - April 2022 - 8

TECHNICAL INNOVATIONS
" This cable would be useful for all EVs, including light-duty passenger vehicles,
Class 8 trucks and other commercial vehicles. "
charge time would require that the
power ratings and charging cable be
rated at 2,500 A.
Commercially available charging station
cables are liquid cooled, using the
principle of forced convection heat
transfer, noted Devahdhanush. In this
conventional cooling technique, fluid
absorbs heat from the cable. After the
heat is dissipated to the external surroundings,
the fluid temperature falls
and the cooling cycle continues.
The Purdue cable design incorporates
a liquid-to-vapor cooling process. A
dielectric heat transfer fluid flows within
the cable conduit that surrounds the
wires. When the wires' surface temperature
becomes greater than the fluid's
boiling point, the liquid starts boiling at
the wire surface and small vapor bubbles
are produced.
" These vapor bubbles slowly condense
back to liquid after departing the surface
because the bulk liquid temperature is so
low, " Devahdhanush explained. " Any remaining
vapor at the exit of the cable is
condensed back to liquid, and the overall
coolant temperature is lowered in a condenser
at the charging station. "
A cool cable is required at charge stations
for safety reasons. An overheated
cable isn't safe for humans to handle,
and at highly elevated temperatures " the
wires would burn out and cause a fire, "
Devahdhanush said.
Purdue University's charging station
cable R&D team, led by mechanical
engineering professor Dr. Issam
Mudawar, regularly communicates with
a team of Ford Motor Co. researchers
to review findings and provide feedback
on various focus areas. Michael
Degner, senior technical leader at Ford
Research and Advanced Engineering,
noted that this research alliance has
the potential to make EV and commercial
fleet ownership considerably more
appealing and accessible.
The next steps in the project include
testing the innovative charging station
cable on EVs. " We are now negotiating
8 April 2022
Purdue Ph.D.
candidate V.S.
Devahdhanush
monitors system
pressure within the
cable (using an analog
pressure gauge, which
he is touching) and the
flow rate of a dielectric
heat transfer fluid via a
Rotameter flow meter.
Professor Issam
Mudawar (center)
leads a Purdue
University team
working to develop a
new charging station
cable inside the Boiling
and Two-Phase Flow
Laboratory at Purdue's
School of Mechanical
Engineering.
with several cable, coupler, pump, and
heat exchanger vendors as part of our
just-announced Research Center for
Electric Vehicle Charging and Thermal
Management to determine how to commence
such testing, " Devahdhanush said.
2022 will see more battery-electric
vehicle introductions, including the Ford
F-150 Lightning Pro truck that targets
commercial fleet customers. " This cable
would be useful for all EVs, including
light-duty passenger vehicles, Class 8
trucks and other commercial vehicles, "
said Devahdhanush. He believes that a
commercialized version of the prototype
charging station cable would be
especially relevant to Class 8 and other
heavy-duty trucks. " Those vehicles are
equipped with large high-capacity battery
packs that need enormous electrical
power to get fully charged, " he said.
Kami Buchholz
TRUCK & OFF-HIGHWAY ENGINEERING
BOTH IMAGES: JARED PIKE
Truck & Off-Highway Engineering - April 2022

Table of Contents for the Digital Edition of Truck & Off-Highway Engineering - April 2022
