University of Extrication: Thermal Events – Part 3

SUBJECT: High-Voltage Lithium-Ion Vehicle Batteries

TOPIC: Thermal Events

OBJECTIVE: Upon the conclusion of this series, the fire service responder will have a better understanding of the thermal events that can and have occurred involving liquid-cooled, high-voltage batteries at vehicle collision or fire-related incidents.

TASK: Upon the conclusion of this series, fire service responders shall be able to develop department guidelines for dealing with liquid-cooled, high-voltage batteries at a vehicle collision or fire-related incident.

In Part 1, we studied the design of the high-voltage, lithium-ion battery in the Chevrolet Volt. Part 2 reviewed several incidents where a fire-damaged or otherwise physically damaged high-voltage battery either shorted and created sparks or self-ignited. In Part 3 of this series, we review new recommendations from the National Highway Traffic Safety Administration (NHTSA) for responders when dealing with hybrid or electric-vehicle collisions or fires where the high-voltage battery may be physically damaged.

The reality is that during 2011, General Motors reported that Volt owners accumulated nearly 20 million miles of driving without any incident similar to the results in the NHTSA tests. In addition, there have been no vehicle fires as a result

of real-world crashes involving electric vehicles of any brand. NHTSA also reported that they do not believe that Chevrolet Volts or other electric vehicles pose a greater risk of fire than gasoline-powered vehicles. This is good news and represents the fact that automotive engineers are truly focused on making this emerging technology as efficient and safe as possible.

In every situation where the lithium-ion battery either shorted or self-ignited, the Volt battery had been physically damaged either by being in a structure fire or damaged during Federal government crash tests. NHTSA studied the fire incidents we reported on in Part 2, and after consulting with auto and battery manufacturers, investigators, subject matter experts, the U.S. Department of Energy, and the National Fire Protection Association, issued as set of recommendations for first responders in January 2012. Although there may be some further modifications as the research continues, the NHTSA recommendations are well-suited for the fire and rescue service to adopt, train on and put into practice immediately in situations where a hybrid or electric vehicle is encountered at a collision or fire incident. NHTSA also is offering recommendations for motorists, tow truck drivers and scrap yard operators as well. GM has its own protocol that states the batteries of its electric vehicles should be depowered after a significant crash, although at this stage NHTSA says this is a job best left to qualified Chevrolet service technicians.

This model Standard Operating Guideline incorporates the NHTSA recommendations into a more user-friendly, fire service-oriented format that can be modified to suit the format used by your department.

AnyTown FIRE DEPARTMENT

STANDARD OPERATING GUIDELINE

Guidance for Electric and Hybrid-Electric Vehicle Collision or Fire Incidents

PROCEDURE #          XXX.XX

EFFECTIVE DATE: ____________

Purpose

The purpose of this Guideline is to provide department members with direction for operating at vehicle collisions, injury crashes, extrications, fluid spills, dangerous conditions and vehicle fires involving a hybrid or electric plug-in vehicle. Adhering to these guidelines allows department members to be in compliance with the January 2012 recommendations issued by the National Highway Traffic Safety Administration(NHTSA) and appropriate Fire Department SOPs and SOGs.

Procedure

When the nature of any incident that the fire department responds to involves a hybrid or electric plug-in vehicle, the following guidelines are offered for field supervisors and line personnel:

NOTE: Members shall don appropriate PPE including Structural Fire Helmet with chin strap properly donned and ANSI 107-compliant, high-visibility, Class II vest anytime when working in or near moving traffic.

Identification of Vehicle

Once a vehicle is identified as a hybrid or electric plug-in vehicle with collision or fire damage,

•      assure that all emergency response personnel on-scene are aware of this fact

•      advise the Communications Center that a hybrid or electric plug-in vehicle is involved for documentation purposes

Responder Safety at Hybrid & Electric Plug-In Vehicle Incidents

All emergency services personnel on-scene are to consider the high-voltage battery and associated components as fully charged, fully energized, and a potential high-voltage shock hazard.

Stabilization of Vehicle

As a minimum, personnel shall:

•      chock a minimum of one front tire while avoiding a position in the vehicle’s forward path of travel

•      attempt to place the vehicle into Park

•      set the parking brake

•      turn the ignition OFF

•      fully stabilize the vehicle as per department SOP if injured occupants remain inside the collision-damaged vehicle

Electrical System Shutdown: 12 volts

AFTER the ignition is turned OFF,

•      12-volt battery should be located

•      consider operating electric door locks, windows, etc., by inside personnel prior to shutting down the 12-volt power

•      12-volt battery ground and positive battery cables should be disconnected or “double cut” as deemed appropriate per department SOP

Electrical System Shutdown: High voltage

If determined appropriate, based on existing levels of training, experience with hybrid and electric plug-in vehicles, and manufacturer’s recommendations, the Service Disconnect device can be located and operated to assure shutdown of high-voltage current flow.

Hybrid or Electric Plug-in Vehicle Size-up

Supervisory personnel shall assure that an assessment of a collision-damaged vehicle is made specifically to determine if the high-voltage battery is physically damaged, leaking fluids, sparks, smoke, flames, increased temperature, gurgling or bubbling sounds are emanating from the battery compartment. There is a potential for a delayed electrical event or battery fire if the high-voltage lithium-ion battery is physically damaged.

If personnel detect any unusual odors or experience eye, nose or throat irritation, implement recommendations for the high-voltage battery “event” listed below. Venting/off-gassing high-voltage battery vapors are potentially toxic and flammable. Leaking lithium-ion electrolyte typically has a sweet ether-type odor.

High-voltage battery “event” guidance

If a high-voltage battery event such as fire, electrical shorting, smoke/smoke odor, or sweet ether-type odor is present coming from the battery compartment:

•      assume there is a high-voltage battery fire

•      direct non fire suppression personnel to a safe location upwind and uphill from the vehicle; clear of moving traffic

•      operating personnel must wear full PPE and SCBA per department policy

•      ventilate the passenger area by rolling down or removing window glass and/or opening doors

•      apply water to extinguish the battery fire while continuing to adequately cool the high-voltage battery and its casing

•      do not penetrate or contact the high-voltage battery or its casing

•      be alert to delayed ignition or re-ignition of a lithium-ion battery fire even after extinguishment. This may remain an issue until the lithium-ion battery is properly discharged by a factory-trained service technician.

If the high-voltage battery is in fact smoldering or on fire and occupants are still inside the vehicle or are trapped;

•      operating fire, rescue, and EMS personnel must wear full PPE and SCBA per department policy

•      provide a protective hoseline until the occupants are removed

•      ventilate the passenger area by removing window glass and opening doors

•      consider rapid patient extrication

•      use sustained volumes of water for control and extinguishment

Post-incident

As an incident involving a hybrid or electric plug-in vehicle with damage to the high-voltage battery is terminated, Fire Department personnel should:

•  ensure that passenger and cargo compartments remain ventilated, i.e., open windows, doors or trunk

•  request Communication Center to notify an authorized service center or vehicle dealership as soon as possible as there may be additional steps they should take to secure and discharge the damaged high-voltage battery

Towing operator interaction

The fire department supervising officer shall document that the towing & recovery operator has been advised or and acknowledges the following:

•  a severely damaged vehicle with a lithium-ion battery should be stored 50+ feet from any structure or other vehicle

•  vehicle should be monitored for leaking fluids, sparks, smoke, flames, gurgling or bubbling sounds from the high-voltage battery

•  if detected, assume the battery is burning and immediately call the fire department to report the incident

•  physical damage to the vehicle or high-voltage battery may result in delayed release of toxic and/or flammable gases and fire

•  venting/off-gassing from of high-voltage battery vapors are potentially toxic and flammable

TASK: Upon the conclusion of this series, fire service responders shall now be able to develop department guidelines for dealing with high-voltage batteries at a vehicle collision or fire-related incident.