Proceedings
of the
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27-28th August 2015
NUI Galway
LONG, MAHER AND BEATLEY: HEV Safety
FIRST RESPONDER HEALTH AND SAFETY FOR COLLISION
DAMAGED HYBRID ELECTRIC VEHICLES
Mr. James Long
Lecturer (Transport Technology)
Dublin Institute of Technology
Mr. Noel Maher
Managing Director
Automotive Technical Expert Consultant Engineers & Assessors (ATECEA) Ltd.
Mr. Clyde Beatley
Lecturer (Transport Technology)
Dublin Institute of Technology
Abstract
The scarcity of fossil fuels has led vehicle manufacturers to adopt new uses of alternative
energy for automobile propulsion. Consequently, First Responders (i.e. police, fire and
ambulance services) are facing unfamiliar challenges as the popularity of these alternatively
powered vehicles increase.
There are new challenges involving Hybrid Electric Vehicles in incidents such as: vehicle
crash, fire, crash and fire, submerged or partially submerged vehicle. This paper focuses on
these hazards and aims to create and awareness of same for First Responders.
Introduction
The Electric Vehicle (EV) is not a creation of modern times. Indeed, its origins can be traced
th
back to the latter part of the 19 century. In 1900, about 4,200 automobiles were sold [1]:
•
40% were steam powered,
•
38% were battery/electric powered, and
•
22% were petrol engine powered.
Early EVs used lead–acid batteries, a mechanical controller, and an electric traction motor to
rotate the drive wheels and propel vehicle. These EVs competed, more or less, on a par with
the internal combustion until the late 1920s when they went into decline due to their high
initial cost, low top speed, and limited driving range.
Ferdinand Porsche introduced the world’s first Hybrid Electric Vehicle (HEV) in 1901. His
Lohner-Porsche Mixte was a series hybrid that employed hub-mounted electric motors in
each wheel. It was powered by batteries and a petrol-engined generator.
The oil embargo of 1973 rekindled an interest in alternative energy sources for motor
vehicles. But it wasn’t until the late 1990s, that the HEV made its return with the release of
the Toyota Prius in 1997, followed by the Honda Insight in 1999.
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A study carried out in 1949, demonstrated a distinct correlation between motor vehicle
growth and the number of Road Traffic Accidents (RTA) [2]. As HEVs enter the marketplace
in progressively greater numbers, the probability of their kind becoming involved, more
frequently, in an RTA is greatly increasing.
First Responders have been dealing with conventional automotive vehicle electrical systems
for decades without fear of serious injury or electrocution. However, when working with
HEVs, this is no longer true. It is now possible to be seriously injured or electrocuted (killed)
if proper safety procedures are not followed.
Figure 1
The World’s First HEV, the Lohner-Porsche Mixte (Porsche AG)
General HEV Operational Considerations
As a HEV can be powered by the electric motor alone, the internal combustion engine may
be stopped whilst the vehicle is in motion [1]. So, it is important to note that a vehicle can
seem sedentary when stationary. However, if the vehicle’s ignition is left “ON”, a simple
action of depressing the accelerator may cause the vehicle to lurch violently, or for the
engine to re-start (idle/stop mode).
EVs and HEVs utilise high-voltage (HV) circuits that if touched with an unprotected hand
could cause burns, serious injuries or even death by electrocution [1].
High-voltage (HV) battery consists of a number of individual cells that are connected in
series to produce voltages typically in the range of 600 volts. Each cell contains materials
that are toxic and electrolyte that is highly corrosive [3]. The HV battery also contains high
energy, enabling high-voltage to arc into an unprotected person causing injury or death.
Accidental/unprotected contact with any “live” (electrically charged) high-voltage component
can cause serious injury or death. Contact with the battery module or other components
inside the battery box can occur only if the box is damaged and the contents are exposed, or
the box is opened without following proper precautions.
There is also a possibility for delayed ignition, or re-ignition, of a lithium-ion battery fire even
after it is believed to be extinguished. This may remain an issue until the lithium-ion battery is
properly handled/ managed/ conditioned by a qualified person. Re-ignition may appear even
after a few days of idleness [4].
Proceedings
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LONG, MAHER AND BEATLEY: HEV Safety
Figure 2
HEV
Instrument
Cluster – showing the vehicle in
park and the Rev Counter on
“EV” instead of 0 RPM. This
means
that
the
internal
combustion
engine
could
automatically restart at any time
depending on the state-of-charge
of the high-voltage batteries and
other factors (Pearson)
Hybrid Electric Vehicle Incidents
Incidents involving a hybrid electric vehicle (HEV) could include the following:
• Vehicle crash,
• Fire,
• Crash and fire, and/or
• Submerged or partially submerged vehicle [5].
First Responder Procedures
First Responders reacting to any incident concerning HEV, or alternative-fuel vehicle, should
rigorously observe Standard Operating Procedures (SOP) [5]. The following points offer the
reader some general guidance:
Step1: Identify (quick visual)
Vehicle manufacturers are extremely proud of the fact that they produce HEVs. To confirm
whether a vehicle is a hybrid, look for the word “HYBRID” on the rear of the vehicle, or for
special decals along its side [5]. Another quick way of identifying a HEV is to look for the
heavily insulated orange-coloured cables under the bonnet, as well as other markings on the
engine cover.
Figure 3
HEV Rapid Identifying Features
(Pearson)
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Step 2: Immobilise (the high-voltage circuit)
The high-voltage cables can be identified by their distinctive orange colour, and contact with
them should be avoided. High-voltage cables can also be identified by colour of their plastic
conduit:
• Blue or yellow. 42 volts (not a shock hazard but an arc will be maintained if a
circuit is opened), and
• Orange. 144 to 600 volts or higher
The HEV’s high-voltage power cables can usually be deactivated by turning “OFF” the
vehicle’s ignition. This removes the signal current to the System Main Relays (SMRs),
effectively de-powering the relays and isolating the high-voltage to the traction batteries [5].
Conversely, should the vehicle employ a push-button start, its key fob should be removed
and separated from the vehicle at a distance greater than five meters to prevent a surprise
power-up [1].
A further safeguard involves disconnecting the negative battery lead from the 12-volt
auxiliary battery. This removes the 12-volt power source to the HV controller, de-powering
the high-voltage system [1]. Should the collision prevent the auxiliary battery from being
accessed, removing the fuse, or relay, to the HV controller achieves the same result – but,
this requires special knowledge as to where to find same on the vehicle.
In the event of a vehicle collision, were the airbags have deployed, the Airbag Collision
Module (ACM) will automatically de-power the SMRs, preventing the HV electricity from
flowing in the vehicle’s circuits [1].
Note: Electrical power typically remains in the high-voltage electrical system for up to 10
minutes after the HV battery pack is shut off. Never handle, cut, or open any orange
high-voltage power cable or high-voltage component without confirming that the highvoltage has been completely discharged [1].
Step 3: Stabilise (the vehicle)
Permanent magnets are used in the construction of the motor/generators and it is possible
that a high-voltage arc could be produced as the road wheels revolve and produce voltage
[5]. Road wheels should therefore be chocked, and the hand brake firmly applied to prevent
the vehicle from moving.
Should the need arise to move a disabled HEV a short distance, say to the side of the road,
the easiest way is to shift the transmission into neutral and manually push the vehicle [1].
To transport a vehicle away from the crash scene, a flatbed truck should be used. If a flatbed
is not available, the vehicle should be towed by wheel-lift equipment with the front wheels off
the ground (FWD hybrid electric vehicles only). Do not use sling-type towing equipment. In
the case of 4WD HEVs such as the Toyota Highlander, only a flatbed vehicle should be used
[1].
Figure 4
HEV Recovery (Peugeot Ireland)
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LONG, MAHER AND BEATLEY: HEV Safety
When hoisting, or using a trolley jack, particular attention should be paid to the vehicle’s
lifting points. Do not place cribbing under the high-voltage power cables, exhaust system, or
fuel system. Orange cables run under the vehicle just inside the fame rails on most hybrids.
Caution must be exercised as, in some cases; the orange outer casings are not exposed
until a black plastic underfloor shield is first removed [1].
Figure 5
HV cables run in close proximity to a HEV’s jacking points (Pearson)
Thermal Events (Fire)
Continual evaluation is the foremost tactical safety factor for dealing with a vehicle fire.
Firefighters are brave and valuable people, their safety is of paramount importance when
determining how to attack a fire. The fire brigade’s Incident Commander will usually decide
whether to pursue an offensive or a defensive attack [1].
Offensive operations typically expose the firefighter to the heat and smoke of a burning
[vehicle] … extinguishing agent is applied directly where it is needed to overpower the fire.
When an offensive attack is successful, the fire can be controlled with the least amount of
property damage [6]. An offensive strategy is used where a fire is considered not to be too
large or dangerous.
A defensive strategy is used where a fire is too large to be controlled by an offensive attack
and in situations where the level of risk to firefighters conducting the attack would be
unacceptable. The primary objective in a defensive operation is to prevent the fire from
spreading [6]. Thus, extinguishing fluid is either directed onto the fire from a distance, or the
vehicle is left to burn in a controlled manner.
HEVs contain the same common automotive fluids used in conventional vehicles. These
fluids and chemicals may be considered hazardous materials (hazmat) [5] – e.g. burning air
conditioning refrigerant produces phosgene gas, which is a deadly nerve agent [7].
It is generally recommended that a standard offensive attack be performed on a HEV –
unless the high-voltage battery (Nickel Metal Hydride) is on fire. Should this be the case,
experience has shown it is better to let the battery burnout rather than attempt to extinguish it
[8]. There are two principal reasons for this:
1. The HV batteries are encased in a protective box, and it is next to impossible to
access them – except through a tiny vent hole, and
2. The fire typically consumes the hazardous electrolyte, negating the need to clean it up
afterwards.
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Submerged or Partially Submerged Vehicle
Manufacturers of HEVs generally recommend removing a vehicle from water using
standardised extraction methods. They report that there is no risk of electric shock from
touching the vehicle’s body work [8]. As with an out-of-water vehicle mentioned previously,
touching the high-voltage cables, or HV components, should be avoided [5].
Seawater ingress into a Traction Battery, however, can result in sudden electrolysing, which
can generate large volumes of highly flammable hydrogen gas [9].
Conclusion
From our dealings with Emergency Service personnel, it is clearly obvious to the authors that
existing procedures are totally inadequate when confronted with newer and more diverse
vehicle power systems.
In light of this fact, the authors strongly recommend collaborations between Emergency
Service Organisations, the Product Technical departments of HEV manufacturers, National
industrial training providers (SOLAS, Institutes of Technology, etc.), government bodies and
associated public interest groups to develop/deliver education and reference
material/infrastructure to help First Responders stay current with emerging vehicle
technology.
It goes without saying, that failure to follow correct Standard Operating Procedures can
result in serious injury such as an electric shock and chemical burns due to the high voltage
battery installed in Hybrid Electric Vehicles.
Finally, the authors would like to take a moment to remind our readers of the dangers
associated with high-voltage, high-energy electricity – see Figure 6, below:
Figure 6
Reminder of the Dangers of Electricity
Proceedings
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ITRN2015
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LONG, MAHER AND BEATLEY: HEV Safety
References
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[1]
Halderman, J. (2012) Automotive Technology: Principles, Diagnosis and Service. 4
Edition. New Jersey: Prentice Hall.
[2]
Smeed, R. (1949) Some Statistical Aspects of Road Safety Research. Journal of the
Royal Statistical Society, 1949, 112 (S e r i e s A):1– 3 4
[3]
Eaton Corporation (2011) Emergency Response Guide TRDR1100. Michigan: Eaton
Corporation
[4]
CTIF (2014) Information for First and second Responders Rescue and Training
Manual. Brussels: The European Association for Advanced Rechargeable Batteries.
[5]
Halderman, J. (2013) Hybrid and Alternative Fuel Vehicles. 3 Edition. New Jersey:
Prentice Hall.
[6]
Schottke, D. (2014) Fundamentals of Fire Fighter Skills. United States of America:
Jones & Bartlett Publishers.
[7]
ConGlobal (2012) R134a Refrigeration Technician Handbook. United States of
America: ConGlobal Industries.
[8]
Emery, J. (2008) Hybrid Vehicles: Separating Fact from Fiction. United States of
America: Emergency Training Solutions.
[9]
Spek, E. (2014) Seawater Immersion Testing of xEVs. Munich: TÜV SÜD AG
rd