Electric Car - Comparison With Internal Combustion Engine Vehicles - Safety - Risk of Fire

Risk of Fire

In the United States, General Motors ran in several cities a training program for firefighters and first responders to demonstrate the sequence of tasks required to safely disable the Chevrolet Volt’s powertrain and its 12 volt electrical system, which controls its high-voltage components, and then proceed to extricate injured occupants. The Volt's high-voltage system is designed to shut down automatically in the event of an airbag deployment, and to detect a loss of communication from an airbag control module. GM also made available an Emergency Response Guide for the 2011 Volt for use by emergency responders. The guide also describes methods of disabling the high voltage system and identifies cut zone information. Nissan also published a guide for first responders that details procedures for handling a damaged 2011 Leaf at the scene of an accident, including a manual high-voltage system shutdown, rather than the automatic process built-in the car's safety systems. As of August 2012, no fires after a crash have been reported in the U.S. associated with the Volt, the Leaf or the Tesla Roadster.

Pole tested Chevrolet Volt after the fire at MGA reported on June 6, 2011 Arcing event during manual rollover of post crashed Volt's battery, November 24, 2011.

Chevrolet Volt

As a result of a crashed tested Chevolet Volt that caught fire in June 2011 three weeks after the testing, the National Highway Traffic Safety Administration ( NHTSA) issued a statement saying that the agency does not believe the Volt or other electric vehicles are at a greater risk of fire than gasoline-powered vehicles. "In fact, all vehicles – both electric and gasoline-powered – have some risk of fire in the event of a serious crash." The NHTSA announced in November 2011 that it was working with all automakers to develop postcrash procedures to keep occupants of electric vehicles and emergency personnel who respond to crash scenes safe. General Motors said the fire would have been avoided if GM's protocols for deactivating the battery after the crash had been followed, and also stated that they "are working with other vehicle manufacturers, first responders, tow truck operators, and salvage associations with the goal of implementing industrywide protocols."

In further testing of the Volt's batteries carried out by NHTSA in November 2011, two of the three tests resulted in thermal events, including fire. Therefore the NHTSA opened a formal safety defect investigation on November 25, 2011, to examine the potential risks involved from intrusion damage to the battery in the Chevrolet Volt. As opposed to the Volt’s battery, the Nissan Leaf's pack is shielded from damage by a layer of steel reinforcement. Also, Nissan clarified that the Nissan Leaf, unlike the Volt, has an air cooled battery pack that does not need to be disabled after a crash. The Leaf was designed with a battery safety system that is activated in a crash that involves the airbags. The airbag control unit sends a signal mechanically to the battery and disconnects the high voltage from the vehicle. Both the Tesla Roadster and the Ford Focus Electric have liquid-cooling systems, and the Focus battery is enclosed in a steel case. After the initial Volt fire, the NHTSA examined the Leaf and other electric vehicles and said its testing “has not raised safety concerns about vehicles other than the Chevy Volt.”

On January 5, 2012, General Motors announced that it would offer a customer satisfaction program to provide modifications to the Chevrolet Volt to reduce the chance that the battery pack could catch fire days or weeks after a severe accident. General Motors explained the modifications will enhance the vehicle structure that surround the battery and the battery coolant system to improve battery protection after a severe crash. The safety enhancements consist of strengthen an existing portion of the Volt’s vehicle safety structure to further protect the battery pack in a severe side collision; add a sensor in the reservoir of the battery coolant system to monitor coolant levels; and add a tamper-resistant bracket to the top of the battery coolant reservoir to help prevent potential coolant overfill. On January 20, 2012, the NHTSA closed the Volt's safety defect investigation related to post-crash fire risk. The agency concluded that "no discernible defect trend exists" and also found that the modifications recently developed by General Motors are sufficient to reduce the potential for battery intrusion resulting from side impacts. The NHTSA also said that "based on the available data, NHTSA does not believe that Chevy Volts or other electric vehicles pose a greater risk of fire than gasoline-powered vehicles." The agency also announced it has developed interim guidance to increase awareness and identify appropriate safety measures regarding electric vehicles for the emergency response community, law enforcement officers, tow truck operators, storage facilities and consumers.

All 12,400 Chevrolet Volts produced until December 2011, including all Amperas in stock at European dealerships, will receive the safety enhacements. Since production was halted during the holidays, the enhacements will be in place when production resumes in early 2012. Sales will continue and dealers will modified the Volts they have in stock, either before or after they are sold. General Motors sent a letter to Volt owners indicating that Chevrolet will contact them with more details about the service effort scheduled to begin in February 2012.

Fisker Karma

In December 2011, Fisker Automotive recalled the first 239 Karmas delivered to the U.S. due to a risk of battery fire caused by coolant leak. Of the 239 cars, less than fifty have been delivered to customers, the rest were in dealerships. In the report filed by Fisker Automotive with the NHTSA, the carmaker said some hose clamps were not properly positioned, which could allow a coolant leak and an electrical short could possibly occur if coolant enters the battery compartment, causing a thermal event within the battery, including a possible fire. In May 2012 a Fisker Karma was involved in a home fire that also burnt two other cars in Fort Bend County, Texas. The chief fire investigator said the Karma was the origin of the fire that spread to the house, but the exact cause is still unknown. The plug-in hybrid electric car was not plugged in at the time the fire started and it was reported that the Karma's battery was intact. The carmaker release a public statement saying that "...there are conflicting reports and uncertainty surrounding this particular incident. The cause of the fire is not yet known and is being investigated." Fisker Automotive also stated that the battery pack "does not appear to have been a contributing factor in this incident." The NHTSA is conducting a field inquiry of the incident, and is working with insurance adjusters and Fisker to determine the fire’s cause.

A second fire incident took place in August 2012 when a Karma caught fire while stopped at a parking lot in Woodside, California. According to Fisker engineers, the area of origin for the fire was determined to be outside the engine compartment, as the fire was located at the driver’s side front corner of the car. The evidence suggested that the ignition source was not the lithium-ion battery pack, new technology components or unique exhaust routing. The investigation conducted by Fisker engineers and an independent fire expert concluded that the cause of the fire was a low temperature cooling fan located at the left front of the Karma, forward of the wheel. An internal fault caused the fan to fail, overheat and started a slow-burning fire. Fisker announced a voluntary recall on all Karmas sold to replace the faulty fan and install an additional fuse.

BYD e6

In May 2012, after a high-speed car crashed into a BYD e6 taxi in Shenzhen, China, the electric car caught fire after hitting a tree and all three occupants died in the accident. The Chinese investigative team concluded that the cause of the fire were "electric arcs caused by the short-circuiting of high voltage lines of the high voltage distribution box ignited combustible material in the vehicle including the interior materials and part of the power batteries." The team also noted that the battery pack did not explode; 75% of the single cell batteries did not catch on fire; and no flaws in the safety design of the vehicle were identified.

Dodge Ram 1500 Plug-in Hybrid

In September 2012 Chrysler temporarily suspended a demonstration program that was conducting with 109 Dodge Ram 1500 Plug-in Hybrids and 23 Chrysler Town & Country plug-in hybrids. All units deployed in the program were recalled due to damage sustained by three separate pickup trucks when their 12.9 kWh battery packs overheated. The carmaker plans to upgrade the battery packs with cells that use a different lithium-ion chemistry before the vehicles go back on service. Chrysler explained that no one was injured from any of the incidents, and the vehicles were not occupied at the time, nor any of the minivans were involved in any incident, but they were withdrawn as a precaution. The carmaker reported that the demonstration fleet had collectively accumulated 1.3 million miles (2.1 million km) before the vehicles were recalled. The demonstration is a program jointly funded by Chrysler and the U.S. Department of Energy that includes the first-ever factory-produced vehicles capable of reverse power flow. The experimental system would allow fleet operators to use their plug-in hybrids to supply electricity for a building during a power outage, reduce power usage when electric rates are high or even sell electricity back to their utility company.

Fires related to Hurricane Sandy flood

In separate incidents during the storm and flooding caused by Hurricane Sandy on the night of October 29, 2012, one Toyota Prius Plug-in Hybrid and 16 Fisker Karmas caught fire while being parked at Port Newark-Elizabeth Marine Terminal. The vehicles were partially submerged by flash floods caused by the hurricane. In the case of the Toyota's incident, a Prius PHV burned and two other Prii, a conventional hybrid and a plug-in, just smoldered. A Toyota spokeswoman said the fire “likely started because saltwater got into the electrical system.” She also clarified that the incident affected only three cars out of the 4,000 Toyotas that were at the terminal during the storm, including more than 2,128 plug-in or hybrid models. Fisker Automotive spokesman said that the Karmas were not charging at the time of the fire and there were no injuries. After an investigation by Fisker engineers, witnessed by NHTSA representatives, the company said that the origin of the fire was "residual salt damage inside a Vehicle Control Unit submerged in seawater for several hours. Corrosion from the salt caused a short circuit in the unit, which led to a fire when the Karma's 12-Volt battery fed power into the circuit." The company explained that Sandy's heavy winds spread that fire to other Karmas parked nearby, and also ruled out the vehicles' lithium-ion battery packs as a cause of, or a contributing factor to, the fire.