As lithium-ion battery use increases, so do the concerns related to the fire-safety hazards of these devices. Through a series of research efforts and partnerships, NFPA is analyzing storage and safety issues surrounding the power source fueling hundreds of millions of devices — from iPhones to electric vehicles — worldwide.
NFPA Journal®, March/April 2012
By Fred Durso, Jr.
On a November evening in 2009, residents of Trail, British Columbia, were jolted by explosions that some people thought were part of a fireworks display. The bursts were actually the result of a fire at nearby Toxco Inc., a battery recycling facility that houses used lithium-ion batteries that previously powered an array of cell phones, laptops, and electric vehicles.
The explosions intensified as the fire ripped through the battery discharge building, and flaming projectiles from a bunker filled with batteries caused the fire to spread to the adjoining district recycling facility. The Canadian Broadcasting Corporation reported that the fire was so intense that firefighters could only attempt to contain the blaze for several hours before letting it burn out. Since lithium is highly reactive to water, it was feared that attempts to douse the flames might have intensified the blaze. While there were no injuries or deaths, the fire destroyed the battery discharge building. A cause was never identified, but officials speculated that the fire was caused by an internal short in one of the stored batteries.
Incidents like the Toxco fire have underscored the flammability and combustibility hazards associated with lithium-ion batteries. Concerns related to the protection of large quantities of batteries in storage settings against potential fires are expected to rise as more technologies embrace this popular power source. Market projections indicate that lithium-ion battery use is growing at about 20 percent per year, replacing other battery chemistries due to the superior makeup and power provided by lithium-ion batteries. Cabot, a global performance materials company, reports that battery makers sold about $8 billion of lithium-ion batteries globally last year. By 2020, Cabot says, that number is expected to increase to more than $18 billion.
Among the many industries looking to this emerging source of power is the auto industry, which has incorporated lithium-ion technology into its latest crop of electric vehicles (EVs). President Barack Obama has pledged to have a million EVs on U.S. roadways by 2015, a goal supported by U.S. Department of Energy Secretary Steven Chu, who recently said the country has a “good shot” of attaining this target. But the battery technology used in these vehicles recently came under scrutiny when a Chevrolet Volt caught fire weeks after a crash test performed as part of a new-vehicle evaluation by the National Highway Traffic Safety Administration (NHTSA). The incident prompted an NHTSA investigation as well as a congressional hearing, where politicians grilled NHTSA and General Motors officials on the vehicle’s safety, as well as on the timing of the NHTSA study. (For more on the NHTSA study, see “Crash + Burn.”)
As dialogue on battery safety continues, NFPA is working with government agencies, insurers, and car manufacturers to address a national issue of emergency responder and consumer safety, and is offering its input and expertise to address the potential risks. The Fire Protection Research Foundation has initiated a study to identify the hazards, research gaps, and best suppression methods for batteries in storage settings. NFPA’s Electric Vehicle Safety Training Project continues to educate the emergency responder and law enforcement communities on the safe handling of these batteries. Staff members have worked with NHTSA to develop guidelines for emergency responders on handling fires involving EVs and hybrid-electric vehicles.
“NFPA is uniquely situated to assist NHTSA and America’s responders in looking at the challenges posed by the next generation of vehicles,” says Ken Willette, NFPA division manager of Public Fire Protection. “We can draw from our technical expertise to provide best practices when responding to incidents involving these cars. If you add the Foundation’s efforts in examining lithium-ion battery storage practices and extinguishing fires involving these battery packs, NFPA was the right choice to support NHTSA’s work.”
The storage challenge
Lithium-ion batteries pack more energy per volume than other rechargeable battery chemistries — such as the notoriously weighty lead-acid batteries traditionally used in certain cars — and have resulted in lighter and sleeker designs for consumer electronics. (See “Staying Energized” for a primer on the science of lithium-ion batteries.) The appeal of this battery type extends beyond its size and power, since these power sources are able to maintain the bulk of their charge for months at a time when not in use and typically require minimal maintenance.
But the technology also comes with its own hazards. Late last year, retailer Best Buy and the Consumer Product Safety Commission recalled battery cases made for specific Apple iPhones following incidents of battery overheating that burned more than a dozen users. Tests on the battery packs in the Chevrolet Volt, General Motors’ EV that also relies on a gasoline generator for power once the lithium-ion battery pack is discharged, also prompted fires, though no incidents of Volt fires on roadways have been documented.
Addressing the potential fire hazards related to this technology, the Fire Protection Research Foundation’s Property Insurance Research Group (PIRG) initiated the Lithium-Ion Battery Storage Protection Project last year to address potential fire risks involving these batteries in bulk storage and distribution settings. “What we’re seeing is an emerging issue,” says Richard Gallagher, line of business director–property for Zurich Services Corporation Risk Engineering and a PIRG member. “We realized that we’re going to see warehouses filled with these batteries, but we really don’t know how to protect them. Nowhere is there guidance whatsoever to direct a building owner on how to protect this commodity.”
The project’s first phase was a literature review commissioned last year by the Foundation that identified these gaps in fire protection and assessed battery hazards. Among the hazard issues addressed in the final report, Lithium-Ion Batteries Hazard and Use Assessment, was the battery’s makeup, particularly its high energy density and flammable solvent that aids ion movement in battery cells during charging. The report also identified the rare, yet potentially dangerous, circumstances leading to battery failure, including poor cell design or defects leading to short circuits, cell manufacturing flaws, external abuse of cells, and charging inadequacies. The rapid self-heating of a cell, known as “thermal runaway,” is what the report terms an “energetic failure” that may cause the electrolyte to combust, potentially leading to a fire spreading to other battery cells or venting of potentially flammable vapors.
While there have been numerous studies conducted on small quantities of cells and small battery packs, little is known about the fire hazards of thermal runaway reactions, how these batteries burn in large quantities, or what suppression tactics are most effective. “This is a commodity that’s become ubiquitous, and the fact that it’s become ubiquitous before we’ve resolved these kinds of issues tell how well [lithium-ion batteries] work,” says Celina Mikolajczak, senior managing engineer with Exponent, the engineering and scientific consulting firm that developed the research report for the Foundation. “They have been in the marketplace for about 20 years, originally in small volumes. As more cells are being shipped and more people use them, we certainly want to be aware of the associated risks, especially as bigger batteries are developed and we contemplate greener technologies.”
PIRG met last August at the Foundation’s Lithium-Ion Battery Storage Hazard Assessment Workshop in Baltimore to discuss findings from the Foundation’s report and remaining gaps in fire hazard and suppression research. The workshop’s “general battery storage” subgroup agreed that full-scale fire tests in these settings would determine the appropriate containment methods.
Heeding this advice, PIRG will begin testing this year as part of the second phase of its research project, which also includes determining the appropriate fire protection commodity classification for lithium-ion batteries. Exponent has already identified various commodity types and their challenges relative to bulk storage protection. PIRG has condensed its research list to two particular commodity types: small-format battery packs, and cells packed in large modules that when combined form EV batteries. PIRG will share the commodity classifications and testing results with NFPA 13, Installation of Sprinkler Systems, technical committees in order to aid the development of provisions related to lithium-ion battery storage. “Once the nature of the commodity is understood, the next step is to identify compatible fire extinguishing agents and design guidelines that the NFPA 13 committees can use to fill the current voids,” says Gallagher.
The EV challenge
Lithium-ion car batteries received their fair share of attention over the past year. NHTSA, which occasionally assesses vehicles that incorporate new technology, initiated a series of tests on EVs last year. According to the agency’s Chevrolet Volt Battery Incident Overview Report published in January, a crash test in May involving the Volt resulted in the leakage of battery coolant, damage to some of the battery’s cells, and an electric short that precipitated a fire three weeks after the crash.
During another round of tests in November, batteries began to smoke and emit sparks, while another caught fire a week after the tests. Though NHTSA isn’t aware of any roadway crashes resulting in EV battery fires, it opened a defect investigation on the Volt on November 25 to further analyze the findings. A month later, GM proposed several modifications to the Volt, including the strengthening of the car’s structure to further protect the battery pack during a collision and the addition of a sensor to monitor coolant levels. The upgrades will be applied to vehicles in production, as well as to the more than 8,000 Volts already on the road.
Also in November, NHTSA contacted NFPA to help assemble a series of interim guidelines for emergency responders, tow truck operators, consumers, and storage facilities to consider in the event of an EV or hybrid-electric vehicle fire. Staff members and consultants with NFPA’s Electric Vehicle Safety Training Project and Public Fire Protection Division, who are well versed on handling various hazardous materials and response procedures, collaborated for the new project. NFPA is incorporating the interim guidelines into its EV training project, which instructs emergency responders on the growing fleet of EVs and related hazards through a series of online and classroom trainings.
“I’d compare NFPA’s role in developing the interim guidelines to a fire ground commander calling in a specialty team to assist with a challenging situation,” says NFPA’s Willette. “NHSTA called us to provide technical guidance and insight into the development of the interim guidelines. The NFPA team responded, with all members focusing on their tasks until the mission was accomplished.” With that input, Willette says, NHSTA was able to draft the interim guidelines.
Following the creation of the guidelines and structural safeguards for the Volt, NHTSA concluded its investigation in January. “NHTSA does not believe that the Chevy Volt or other electric vehicles pose a greater risk of fire than gasoline-powered vehicles,” the agency said in a statement. (NFPA statistics indicate that in 2010 there were roughly 184,000 highway vehicle fires, nearly all of them in gasoline-powered vehicles, that resulted in 285 deaths.) “The agency expects this guidance will help inform the ongoing work by NFPA, the Department of Energy, and vehicle manufacturers to educate the emergency response community, law enforcement officers, and others about electric vehicles.”
The manner in which NHTSA responded to the series of fires involving the Volt perplexed some politicians. A subcommittee of the House Oversight and Government Reform Committee held a hearing in January with NHTSA Administrator David Strickland, along with Dan Akerson, General Motor’s chairman and chief executive officer, to question NHTSA on why it waited six months after the initial battery fire to launch an official investigation. The proceedings were at times acrimonious. “Your agency dropped the ball on this,” U.S. Rep. Mike Kelly, a Pennsylvania Republican and committee member, said to Strickland at the hearing, according to the Grand Rapids Press. “For me, it comes down to taxpayer dollars being used to subsidize a product that this administration wants to go forward.”
Strickland acknowledged the safety of the Volt and pointed out that there had been no on-the-road incidences of battery fires. He also testified that engineers used that time to meticulously analyze the cause of the fires. Had there been a public safety concern, Strickland said, NHTSA would have brought the issue to light sooner.
Gregory Cade, NFPA division director of Government Affairs, attended the hearing and noted that both Strickland and Akerson complimented NFPA for its involvement in developing the interim guidelines and on its collaboration with GM on aspects of NFPA’s Electric Vehicle Safety Training Project. “The dilemma is that GM is only one carmaker using one battery technology,” says Cade. “We’ve got to continue to reach out to other car and battery manufacturers. They’re not all using the same technology.”
NFPA has also continued expanding its EV training to other interested parties. The Department of Energy, which had initially awarded NFPA a $4.4 million grant in 2010 for its EV training project, recently extended participation to EMS and law enforcement officials. More than 15,000 people have already registered for an online training course featuring electrical and safety information on the Volt. The course complements the project’s “train the trainer” classroom courses attended by about 800 fire service professionals in 20 states. Anticipated for release this year is a reference guide that instructs emergency responders on identifying all makes and models of hybrid cars and EVs as well as how to safely respond to the vehicles in an emergency.
The training developments underscore NFPA’s role as the authority on EV battery safety, says Andrew Klock, senior project manager for the EV Safety Training Project. “The training is exceeding our expectations,” he says. “The attendance across the country has been much better than we anticipated. We thought we would have 45 fire service trainers in each state taking the course. In many states, we’re pushing over 100. The EV Safety Training Project website is also becoming the place where the emergency responder community is getting their hybrid and EV safety information.”
Looking ahead, the Foundation is partnering with the automotive industry and the Department of Energy (DOE) this year to develop best practices for the safe handling and disposal of damaged automotive batteries by emergency responders. The project is yet another aspect of the larger effort to assess and address the fire protection strategies of this rapidly emerging technology.
“EV battery safety represents a special challenge as this technology is in a rapid state of evolution,” says Kathleen Almand, the Foundation’s executive director. “Both NFPA and the Foundation have been proactively addressing many new energy-related technologies, from solar panels, to biofuel safety, to electric safety aspects of plug-in EVs to ensure that NFPA standards are appropriately addressing all of these emerging issues.”
Fred Durso, Jr. is staff writer for NFPA Journal.