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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 (GM) 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 a 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 (below) incorporates the NHTSA recommendations into a more user-friendly, fire service-oriented format that can be modified to suit the format used by your dept.
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.
Ron Moore will present “The Challenges Of Extrication Involving Vehicles With Advanced Steel” and “Hybrid & Electric Plug-In Vehicle Fire & Rescue Procedures” at Firehouse Expo 2012, July 17-21 in Baltimore, MD.