Automotive Engineering - March 2022 - 21

PROPULSION FEATURE
developing motors capable of higher
rpm typically enables more power output.
" If you can go for more rpm, you
basically can get more output from the
motor, " Curran explained. " You have a
constant torque phase, and then you
get a constant power phase. That power
phase comes in after you're through
that constant torque speed. As the
speed keeps going - obviously power is
speed-based - you can get more and
more power as you go along. "
Lucid already has won acclaim for its Air
motors' combination of monstrous power
- ranging from 480 hp to 670 hp, depending
on trim and battery-pack configuration
- and industry-leading driving range. To
get there, chief engineer Bach said the
company's engineering teams focused on
efficiencies - chiefly windings and thermal
management, but even gear-tooth design
- for its highly power-dense yet ultra-compact
PM motor. (The company claims the
entire drive module can fit in an airline
roller bag and weighs just 163 lb [74 kg]).
The Air platform's system architecture also
operates at 900V, which also has a significant
impact on power potential.
The Lucid drive motor has carefully
calculated windings the company dubs
" continuous-wave " because of the way in
which the rectangular copper is precision
laser-welded, rather than the typical
" hairpin " copper windings pressed into
slots. " The winding pattern has been developed
in house to achieve a fundamentally
efficient and torque-dense electromagnetic
layout, " explained Bach. " The
electromagnetic simulations, the flux simulations,
the thermal simulations - that's
all done in house. And then we've developed
the winding not just to be great
from a performance perspective, but so
that it's really easy to manufacture. " Bach
also claims the Lucid design uses " about
half as much copper as the competition. "
He added that a clever augmentation
to the motor's powerful cooling of its
windings comes easily - and at almost
zero cost. As the stator stack's laminated
layers are stamped, the dies are indexed
to punch a portion of the winding cooling
channels into each layer. " We punch that
entire lamination stack with the cooling
channels included for free. "
AUTOMOTIVE ENGINEERING
We were too.
That's why we invented
the wave spring.
* Optimize Application Space & Weight
* Industry-Specialized Design Support
* Large Selection from Stock
* Easy to Customize
As scrutiny mounts about electrification's
impact on scarce and expensive
minerals, engineers are focused on reducing
rare-earth content in motors.
Renault and Valeo are developing rareearth-free
motors, in which windings
replace the permanent magnets.
Production is aimed at 2027.
" There are lots of reasons not to
want to put a bunch of rare earth in
there, " asserted GM's Curran. " It's not
just from where it comes from, but it's
AE Smalley Steel Ring Ad 0322.qxp_1/2 Page Island 2/10/22 11:29 AM Page 1
Crest-to-Crest® Wave Springs
Request Free Samples at 847-719-5900 or smalley.com
Free Info at http://info.hotims.com/82330-709
March 2022 21
SICK OF
COIL SPRINGS?
http://info.hotims.com/82330-709
Automotive Engineering - March 2022

Table of Contents for the Digital Edition of Automotive Engineering - March 2022
