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Hydrogen goes further
Range anxiety – where
drivers worry that their
battery will run out of power before
they reach their destination – is still
preventing the widespread uptake of
electric vehicles (EVs). For the carbuying
public it represents a serious
issue, and for commercial users it
is absolutely critical, with jobs and
businesses being directly a ected.
The average trip in an electric car
is just 10 miles, but commercial vans
and buses have to run all day long.
Starting, stopping and accelerating
all impact the performance of the
EV’s battery pack, and range can
also decline as the battery pack
starts to age.
By way of an example, the latest
88-passenger electric bus being
developed by Daimler has a massive
243kWh Li-ion battery resource to
power its motors. However, even
this is not enough to handle all the
routes that buses will normally have
to travel, powering only about 80%
of the journeys. This leaves bus
operators with a headache – electric
versions are applicable for some
routes and diesel-powered versions
are still needed for others.
Meanwhile, van operators
face a di erent challenge. The
more batteries the van needs for
its rounds, the fewer packages it
can deliver, because the batteries
take up valuable space.
These and other kinds of
commercial enterprises want
to adopt electric power to lower
their running costs and tackle the
growing emissions problem, but
they must ensure their vehicles
return at the end of each day
for recharging. While research
into increasing battery capacity
continues, a practical solution
is needed today.
By having a charged battery
working in tandem with a hydrogen
gas reserve, the EV range can be
extended substantially. Hydrogen is
combined with oxygen in a fuel cell
to generate electricity for driving the
motors directly or, more often, to
keep batteries topped up. This has
the added benefit of avoiding too
much current drain on the batteries,
which can reduce their lifespan.
A hydrogen range extender can
be located on an EV’s roof, thereby
avoiding taking up valuable cargo/
passenger space. This also means
that flammable hydrogen is kept
well away from Li-ion battery packs,
which can potentially overheat.
The fuel cell employed in this
arrangement comprises a stack
of proton exchange membranes
that can handle the combination
of hydrogen and oxygen. Because
the only by-product from the fuel
cell is water, the vehicle maintains
a very low overall carbon footprint,
especially if an electrolysis process
powered by renewable energy
produces the hydrogen.
152 // January 2020 // www.electrichybridvehicletechnology.com
This all sounds very appealing,
and fleets of vans employing this
technology are already starting to hit
UK roads, but there are still certain
technical di iculties to consider. The
hydrogen is stored at 300bar in the
vehicle, which requires a robust tank
with reliable pressure valves – and
these have associated engineering
costs. Then there is the matter of
hydrogen refueling, because there is
very little supporting infrastructure
currently in place.
To address this, many companies
are now installing electrolyzers to
produce hydrogen on site. These are
built-in 40-foot containers, making
them easy to manage. It should be
noted, though, that the hydrogen
changes temperature as it moves
from the electrolyzer storage into
the range extender, so cooling
is required.
Hydrogen can also be distributed
by specialty chemical suppliers in
canisters. These can boost the
range of smaller vans without
having to worry about refueling
infrastructure. There are also
moves in the UK to utilize part of
the already-established natural
gas delivery network to transport
hydrogen for this purpose.
Battery power, along with
fuel cell range extension, o ers an
added dimension to commercial
fleet operators’ e-mobility strategies.
Whereas pure-play EVs struggle
with a full day’s usage, range
extenders can provide that
necessary extra capacity, and
the technology also helps
protect the battery.
While battery packs and fuel cells
both have to be replaced around
every 20,000 miles, by working
together they can keep commercial
vehicles running much longer.
How hydrogen fuel cells can set minds at
rest by extending the range of electric vehicles
Fuel cell hybrid electric buses have a much greater range and longer battery life than regular EVs
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