megatrends

Power cut: EV makers focus on
post-crash performance
What are the fundamental differences
between electric vehicle (EV) and
internal combustion engine (ICE) car
safety?
The core difference between EV and ICE safety
is that we have familiarity with ICE technology
developed over many years, yet for many, EV is
new and unfamiliar. The vehicle manufacturers
and the other technology providers are
naturally striving to develop the most efficient
EV that today’s technology constraints will
allow; yet as soon as that vehicle is launched, it
is released on consumers, service and repair
industries, and emergency services largely
unfamiliar with it. EVs were keenly promoted
in the early 20th century, but in reality, since
marketing of the Mitsubishi i-MiEV and the
Nissan Leaf began, Thatcham has managed a
surge of concern from many sectors within
and outside of the industry.
How do the safety requirements differ
between different forms of electrified
powertrain, for example, between
battery electric vehicles (BEVs), hybrid
EVs (HEVs), plug-in hybrid EVs (PHEVs)
and fuel cell EVs (FCEVs)?
With HEVs and PHEVs, the lack of
knowledge is compounded, because to the
untrained it appears to be an ICE vehicle.
OEMs have done well with the safety
protocols for EVs with automatic cut-out of
the high voltage system governed by the SRS
[safety restraint system]. Yet this does not
account for every emergency scenario. We
know from our collaboration with the
emergency services regarding casualty
extraction that they often require the
electrical system to be active for moving
electric seats to a position where a driver
with spinal injuries can be safely extracted.
With an ICE vehicle, the fuel cut-out reduces
the risk from fuel system fire, but leaves the
electrical system operating. With an EV, there
are a number of components that still
present a risk, even after the high voltage
system which powers the engine has been
‘locked out’. Capacitors still hold charge, the
magnets in the motor rotor mean it can
Megatrends
Despite the slow start that many high profile battery electric vehicles have made in terms of sales,
there is widespread agreement that new cars will increasingly use some form of powertrain
electrification. Bringing live electricity into a vehicle, be it battery electric, plug-in hybrid or fuel cell, adds
complexity to the safety features designed and developed for that vehicle. Nevertheless, in late 2012,
the Volvo V60 Plug-in Hybrid scored five stars in its Euro NCAP test; in the US, the 2013 Ford Focus
Electric recently scored five stars in its NHTSA NCAP test.
In 2012, Thatcham research in the UK became the eighth Euro NCAP-accredited test lab.
Megatrends spoke to Andrew Hooker, Future Vehicles Engineer at Thatcham Research, about the
safety aspects of electric vehicles
Martin Kahl
move and align itself, and the battery itself
remains susceptible to temperature.
Should EVs undergo different safety
tests from ICEs?
No, at Thatcham we do not as yet believe this
is necessary. We have the very successful Euro
NCAP programme that is far more than just a
test of the vehicle structure, with aspects such
as pedestrian safety and ADAS [advanced
driver assistance systems] technologies being
assessed. A well known incident in the US, in
which NHTSA crash tested an EV which
subsequently caught fire, did exactly what it
should have done: it identified an issue, albeit
in less than ideal circumstances.
Q1 2013 Automotive World Megatrends magazine | www.automotiveworld.com
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