Truck & Off-Highway Engineering - October 2023 - 21

Battery chemistries for
CONSTRUCTION
Large excavators with operating weights of more than 6-tonne
are a segment OEMs are looking to electrify further. Komatsu's
18-tonne PC210LCE electric excavator features Proterra lithiumion
battery technology with 451 kWh of capacity.
ELECTRIFICATION FEATURE
EVs
NMC and LFP lithium-ion batteries find favor in different regions as OEMs move
to electrify larger excavators and loaders.
by Dr. James Jeffs
T
he success of electric vehicles in the construction industry
will largely be determined by battery prices being low
enough that the total cost of ownership is cheaper than diesel
alternatives. IDTechEx's new report, " Electric Vehicles in
Construction 2023-2043, " shows that there is a battery price tipping
point, under which it will be cheaper over the vehicle lifetime to operate
an EV. Selecting the right chemistry will be imperative for getting
a low enough vehicle price. So why is a clear dichotomy seen
between the batteries being deployed in China compared to Europe?
Electric vehicles in construction are an emerging market. IDTechEx has
built a database of more than 100 example makes and models across
seven different construction-vehicle categories: mini excavators, excavators
(>6 tonne), compact loaders, backhoe loaders, wheel loaders, telehandlers
and mobile cranes. However, with lots of vehicles yet to be released,
only 49 database entries have confirmed chemistry information.
Europe and China have more established markets for electric construction
vehicles, which makes it possible to draw some conclusions
about battery-chemistry trends from OEMs in these regions. What is
obvious at this early stage is that Europe heavily favors NMC (nickel
manganese cobalt) lithium-ion batteries, while China has chiefly chosen
LFP (lithium iron phosphate) batteries.
Battery requirements in construction vehicles
So, why would one select NMC, LFP or even lead acid? A battery that
electrifies construction equipment needs to have huge capacity and
low cost. Some of these machines are extremely large and usually
require concrete counterbalances to handle the massive loads they
encounter. What this means for electrification is that battery weight
isn't much of an issue.
Power density also is not a priority. Unlike electric cars, construction
TRUCK & OFF-HIGHWAY ENGINEERING
vehicles do not tend to have large power-demand spikes
and are more likely to operate at a steady rate for a long
time. As an example, some early Tesla Model S EVs had
a 60-kWh battery and a 210-kW motor power, meaning
its battery must be able to deliver a peak of 3.5C (power
divided by capacity), typical for road cars and why they
tend to favor power-dense chemistries like NMC.
By contrast, the Volvo L25 electric compact loader has a
battery capacity of 40 kWh and a maximum motor power
of 36 kW, so the battery is only required to discharge
at a maximum of 0.9C, well below road-car expectations.
The same is true when considering the larger machines.
The XCMG XE270E is a 27-tonne excavator
with a battery capacity of 525 kWh, but its motor is a
paltry 140 kW (~0.27C). In fact, research in the
IDTechEx report shows that the vast majority of electric
construction vehicles have a peak discharge requirement
of less than 1C, with one-quarter of vehicles
requiring less than 0.5C peak discharge.
A low peak discharge requirement can be fulfilled by
lead-acid batteries, which is likely why it was explored
in the early days of construction electrification. The
European examples that used lead acid were mainly
from the mid-2010s, when lithium-ion technologies
were still scaling and were much more expensive than
lead acid. However, these vehicles were seriously limited,
with low endurance and slow recharge times. Lead
acid was replaced with lithium-ion once the newer technology
became more financially viable.
Both NMC and LFP offer the required performance
for construction, coping with the peak discharge
October 2023 21
KOMATSU
Truck & Off-Highway Engineering - October 2023

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