SAE Update - November 2021 - 14

FOCUS:POWERTRAIN
AND PROPULSION
Electrification and
the other " E " - E-fuels
packs have high-voltage
connection between the pack
and the chassis. They have a
communication interface and
very often they have a cooling
interface. These interfaces
typically are not designed to be
made and broken once per day
for 5,000 cycles, so there's a
durability risk that would need to
be overcome.
" The other issue is what I like
to call the 'propane-bottle
exchange program.' If you have a
propane bottle on your grill at
home and it runs out, typically
you don't go and get it refilled,
you swap it. That's fine, because
you pay $25 and you don't care.
If you're driving your truck in,
swapping out your $12,000 or
$20,000 battery pack for one
whose lineage you're not familiar
with, you may find the next day
you go to drive your truck your
range has been reduced by 30%.
So, that limits it to maybe fleets
having their own [dedicated]
swapping systems.
" Swapping systems also take a
lot of space. You need robotic
systems to move these battery
packs, which are probably the
footprint of a ping-pong table
and a foot thick or more, in and
out of trucks. It turns out to be a
14
November 2021
" So, there's a lot of potential [for e-fuels] if the regulations allow that as an
energy transport mechanism in the futuren " said 22-year SAE member
Philip Stephenson in his COMVEC 2021 presentation.
lot of infrastructure, and there are alternatives like
fast-charging or hydrogen. "
Asked what the barriers are to hydrogen fuel-cell
use in the next decade, he said: " First of all,
infrastructure. Distribution of hydrogen will continue
to be an issue. Storage density of hydrogen on trucks
isn't great. If you look at the back of that Kenworth/
Toyota fuel-cell truck, to store 60 kg of hydrogen [six
tanks capable of operating at 700 bar], we have a
closet on the back that is three or four feet deep and
the full height of the tractor. That's not very good
energy density, so that's a concern as well. "
" And there's relatively high costs that go into a fuelcell
stack, " he added. " They contain precious metals,
very expensive to make, and that will need to improve
probably by an order of magnitude for them to get
competitive with battery systems. " n
UPDATE
Ryan Gehm/SAE International
SAE Update - November 2021

Table of Contents for the Digital Edition of SAE Update - November 2021
