Automotive Engineering - March 2022 - 8

TECHNOLOGY REPORT
ELECTRIFICATION
Purdue prototypes new EV fast-charge cable
Acquiring e-Traction has accelerated Saietta's
development of truck and bus electric axles.
Outboard marine drive
Saietta launched the latest application
for its AFT at the Marine Equipment
Trade Show (METS) in Amsterdam in
November 2021. The company launched
a new division devoted to marine propulsion
with two new designs under the
brand name Propel. The first is an outboard
motor and the second a replacement
for light marine diesel engines
used in leisure craft and work boats,
both powered by Saietta AFT motors.
The D1 inboard engine range uses lowvoltage
motors and does not need a
gearbox. Included in the package are a
sunlight-readable 5-inch (12.7-cm) display
and a side-mounted " throttle " lever,
as well as a DC inverter to power onboard
12-V devices. For the Propel S1
outboard motor, Saietta has drawn on
existing designs for the shaft leg and also
designed and produced a closed-loop
cooling system filled with glycol, so the
motor could be left in place through the
winter. It also removes the need for a
cooling-water intake below the waterline.
The motor and control electronics all
are housed above the waterline. Saietta
claims a 10-kW continuous power output
from a 48-V battery. Using Saietta's
own four-bladed propeller, this should
produce 3.75 kW of propulsive power.
" You can optimize your propeller because
you don't need an exhaust in the
middle of that prop, so that helps a lot, "
Kist said. " Then, it's just a shaft that
goes up with an internal spline in our
motor, with integrated inverter and it
just goes on top. "
John Kendall
8 March 2022
Purdue Ph.D. candidate V.S. Devahdhanush monitors system pressure within the charging cable and
the flow rate of a dielectric heat transfer fluid via a Rotameter flow meter.
A new charging station cable designed
by a Purdue University research team
could enable an electric vehicle (EV)
battery to be recharged in under five
minutes, comparable to filling an average
passenger vehicle's fuel tank at a
gas station. The patent-pending technology
" addresses a better thermal
management scheme for EV charging
cables based on the principles of subcooled
flow boiling. This would enable
ultra-fast charging of EVs by the safe
passage of much higher electrical currents
through the cable, " said V.S.
Devahdhanush, a Purdue University
Ph.D. candidate and research project
team member.
The Purdue team's prototype charging
station cable is designed to dissipate
heat as electrical current flows
through the cable. In comparison to the
cable used by Tesla on its Supercharger
V3 - currently considered the fastest
charger in the U.S. market - the prototype
cable delivers 4.68 times the current,
according to Devahdhanush. The
Tesla V3 supercharging architecture
supports peak charging rates up to 250
kW per car.
To achieve a faster charge rate, a
cable needs to enable higher electrical
current flow. " We've been able to demonstrate
experimentally the safe,
steady passage of 2,438-amp current
through a 0.25-in wire, " Devahdhanush
said, noting higher values are theoretically
possible. With a 10-foot long (3m)
cable containing two high-direct
current wires, equivalent to a single
20-foot wire, 24.22 kW of heat is removed
via the cooler cable providing
2,438-A current.
Most of today's charging stations can
deliver current up to approximately 520
A. However, DC fast chargers typically
deliver less than 150 A. Charging times
vary from approximately 20 minutes to
several hours, depending on whether a
AUTOMOTIVE ENGINEERING
FROM LEFT: SAIETTA; JARED PIKE

Automotive Engineering - March 2022

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