Automotive Engineering - August 2022 - 10

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Cadillac Lyriq spearheads GM's EV assault
to reduce mass, however. At 5610 lb.
(2545 kg) and a 121.8-in. (3024-mm)
wheelbase and 196.7-in. (4996-mm)
overall-length footprint, the base RWD
Lyriq is no featherweight, although like
many EVs, the grunt of electric propulsion
often masks plump curb weight.
If you're looking for the much-coveted
The 2023 Lyriq has low-roofed wagon cues and a unique silhouette, but there's no " frunk " under
the broad hood.
The 2023 Cadillac Lyriq isn't the first of
GM's new-age EVs to use the company's
all-encompassing Ultium lithiumion
battery " system " and all-new family
of traction motors. That distinction goes
to the GMC unit's Hummer EV, but the
Cadillac's first-ever EV arguably is
more important than the outsized and
outlandish Hummer. Lyriq is vital to
demonstrating GM's vision for scaling
EV batteries and modular vehicle architecture
for a wide range of models,
from mainstream to luxury.
There's another angle to Lyriq's impact
in the market, though. Cadillac itself
needs to prove it's got the goods to take
on the rapidly expanding universe of luxury
EVs, led, of course, by Tesla. For now,
better judge the Lyriq strictly on its competitive
merits, however: Cadillac refuses
to discuss production volumes from its
Spring Hill, Tenn., assembly plant.
Although executives said 2023 models
are sold out and 2024 ordering was
opened in late June, LMC Automotive
reportedly projects a total run for both
model years of just 22,000 units.
All chips wagered on Ultium
Jamie Brewer, Lyriq's executive chief
engineer, said the 2023 Lyriq boasts a
near 50/50 front/rear weight distribution.
The body and chassis structures
are integrated with the battery. The solidity
of this unified approach, which
10 August 2022
also leverages a variety of mixed materials,
she added, " Goes right into precision
handling. "
Brewer told SAE Media that in the
course of hundreds, if not thousands, of
CAD-based simulations of the body
over the course of the car's four-year
development, the body structure was
almost completely done before any
physical parts were created. All avenues
of lightweighting were explored, including
strategic use of so-called " quiet
steel " (a specialty material developed
and branded by MSC) and " the mostadvanced
acoustic materials. " Program
engineers did not sacrifice driving feel
or structural performance in their drive
EV " frunk, " there isn't one. Brewer said
when initially laying out the Lyriq's modular
architecture, the choice came to a limited-area
frunk and tighter dimensions for
the rear cargo area - or a roomier traditional
rear cargo area with no frunk.
Tim Grewe, GM's director of electrification
and strategy, said the Ultium battery
chemistry of nickel-cobalt-manganesealuminum
(NCMA) relies on aluminum in
the cathode to help reduce the loading
of rare-earth materials such as cobalt;
the anodes are blended graphite. Grewe
reminded that Ultium cuts cobalt content
by some 70% compared to current
batteries used by GM. The flat, pouchshaped
Ultium form factor incorporates
the battery electronics in the cell modules,
which engineers said eliminates
nearly 90% of battery pack wiring.
As recently as 2016, " we couldn't imagine
this cell, " said Grewe. He reiterated that
the Ultium design is " prepared for upgrades "
as chemistry or hardware and
software improvements invariably happen.
The Lyriq's twelve modules, each
containing 24 of the pouch-type cells,
Charting Cadillac's approach
for the EV era, designers
insisted the Lyriq cabin feature
no corporate parts-bin pieces.
AUTOMOTIVE ENGINEERING
BOTH IMAGES: GM

Automotive Engineering - August 2022

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