Automotive Engineering - September 2022 - 22

Chattanooga
COVER STORY
POWER HAUS
Battery standardization 'not quite yet'
Q&A with Dr. Wolfgang Demmelbauer-Ebner, VW chief engineering officer
EV battery technology still is in a state of flux, with competing chemistries,
form factors, etc. Does VW see a standardization coming?
Not quite yet. There is more to come in the chemistries, including solid-state
batteries within the next 5-10 years.
And the form factors will continue to
be fluid, as OEMs change them to meet
different vehicle applications - highfloor
cars, low-floor cars, wide and
narrow battery packs depending on
the vehicle architecture. We are a global
manufacturer and have to build vehicles
for different customers and regions,
so there will not be a single form
factor perhaps for quite a while.
Dr. Wolfgang
DemmelbaurEbner.
Do
you see the 12V lead-acid battery
being designed out of EVs to save
weight and complexity?
No, not any time soon. The 12V battery is inexpensive, reliable, recyclable
and has high energy density for a number of use cases.
What role will your R&D partners from Oak Ridge National Labs and
University of Tennessee be playing in VW's EV developments in
Chattanooga?
Many roles. They have huge expertise not only in batteries but also in other
areas of propulsion technology. We have a super-strong relationship with
them. They're a huge asset for us in identifying new technologies, and also a
good pool for new talent.
Lindsay Brooke
a ramp rate of 3 deg. C per minute. Keysight supplied
its pack-level Scienlab Battery Test System and its
Energy Storage Discovery software for this important
lab, which has 1,000V/900A/360kW battery-charging
capability.
Dust chamber: Supplied by Italy-based ACS
Angelantoni Test Systems, the BEL's sophisticated
dust chamber uses ISO-standardized dust particles,
fed at flow rates up to 2,600 cfm to replicate 70 mph
(113 km/h) road speed, to attack the test pack's seals.
The ISO-certified " Arizona " dust particulate measuring
1/70th of a human hair in diameter often is blended
with abrasive material. A typical dust test at BEL is 20
cycles at 20 minutes per cycle, over approximately
seven hours. This would be part of a sequence of battery-pack
tests that begin with a thermal cycle, then
the dust test, water-jet test at garden-hose pressures,
followed by a high-pressure steam test. The pack then
is completely disassembled and analyzed.
Water immersion and sodium chloride: Salt-bath
An example of the current ID.4 battery pack on display in the Chattanooga packassembly
plant. This 82 kWh pack uses LG-supplied NCM712 cells and weighs 493
lb. A new pack using SKI-supplied NCM811 cells recently entered production.
22 September 2022
tests that simulate up to one year of EV life in a hostile
winter environment (such as southeastern Michigan)
and a water-immersion test that simulates water ingress
after shocking the aluminum case structure, are
keystones in VW's pack development. The 2,100-gal.
(8 sq-m) water-immersion tank, supplied by Floridabased
Equilam NA, heats the pack structure to 140
deg. F (60 deg C) before dunking it into 40 deg. F
water (dyed a color, for easier leak identification) for
five minutes. Each immersion test cycle includes 20
tests that are like a Polar Bear Club outing, but for battery
cases.
AUTOMOTIVE ENGINEERING
The BEL's water
immersion test is a Polar
Bear Club for batteries.
ALL IMAGES: LINDSAY BROOKE
Automotive Engineering - September 2022

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