The global shift toward electric vehicles (EVs) is critical for combating climate change. According to the Environmental Protection Agency, if every household switched one of their main vehicles to an EV, they could collectively save $72 billion in annual fuel costs and reduce greenhouse gases up to 320 million metric tons per year. However, safety concerns that some drivers have are slowing the transition to EVs, particularly related to electric vehicle fires.
It is important to understand contributing factors to EV fires such as overcharging, flooding, manufacturing defects, and high-impact accidents, and explore the features designed to prevent electric cars from catching fire. These considerations help explain how much of a fire risk EVs actually pose compared to gas cars and the unique dangers of EV battery fires, especially in states like Florida with a notable history of electric cars catching on fire.
Additionally, we will go over expert recommendations for preventing electric car fires, the current state of EV fire emergency response, and how EV owners, governments, and automakers can mitigate fire risks with safer battery technology.
How Do Electric Vehicle Fires Occur?
Overcharging
Overcharging is a significant but easily preventable factor contributing to EV battery fires. Excess electrical current flowing into an EV battery can cause it to overheat and enter thermal runaway, a chain reaction that accelerates the release of heat and flammable gases. Battery management systems (BMS) are designed to prevent overcharging, but failures in the BMS can still lead to electric car fires exploding or catching fire.
Flooding
During storm surges and hurricanes, water can infiltrate an electric vehicle’s battery pack, electrical connections, and control systems, causing short circuits and electrical malfunctions that may spark an electric car fire. Additionally, water can corrode connectors and lithium ion (Li-ion) battery components, compromising their integrity and contributing to long-term fire risks.
Manufacturing defects
Manufacturing errors in EV batteries contribute to electric vehicle fires by creating structural weaknesses, poor insulation between cells, or faulty electrical connections within the battery pack. These defects can compromise the safety and performance of the battery, making it more susceptible to thermal runaway. A prime example is the massive recall of the Chevy Bolt in 2020, in which two simultenous manufacturing defects at the battery cell level were linked to fire incidents, forcing General Motors to recall nearly 51,000 cars.
High-impact accidents
Despite having higher crash safety ratings than ICE vehicles, the force of a collision can damage an EV battery, causing highly flammable electrolytes to leak out. Damage to control systems during an accident tends to generate heat and sparks, increasing the risk of an electric car battery fire.[RM2] Accidents can also disrupt the sensitive nature of lithium-ion battery operation, causing a fire to break out days or even weeks later.
EV Battery Fire Prevention Features
Thermal management systems
These use liquid cooling or air cooling to regulate battery temperature, keeping batteries within a safe operating range to prevent EV car fires related to thermal runaway.
Battery management systems (BMS)
These systems monitor and manage individual cells in a battery pack. If any abnormalities in cell voltage, temperature, or state of charge are detected, the BMS can reduce charging or discharging rates to prevent an EV battery from exploding or catching fire.
Fire-resistant materials and design
Several EV battery components are now being made with fire-resistant materials, such as aerogels and coatings, to minimize the chance of fire spreading within a battery pack. Most EVs also have fire-resistant battery compartments, which help contain and isolate any potential EV battery fires.
Emergency disconnect systems
In case of an accident or other emergency situations, these systems allow first responders to safely disconnect EV batteries, potentially preventing combustion and electrocution.
Electric Car Fire Statistics
How many electric cars catch fire every year?
Experts agree it is unclear how many electric cars catch fire every year globally due to incomplete data. In the United States, for example, fire departments reporting vehicle fires to the National Fire Incident Reporting System do not separate electric vehicle fire statistics and gasoline car fire statistics. EV fires are still considered rare events, since EVs only make up about 1–2% of vehicles on the road.
Are electric cars more likely to catch fire than gas cars?
Although electric car fires are a growing concern, EVs are still less likely to catch fire than gas cars. One study shows electric vehicles have just a 0.03% chance of igniting, compared to the 1.5% chance for internal combustion engine vehicles. Hybrid electrics, which have both a high voltage battery and an internal combustion engine, have a 3.4% likelihood of vehicle fires.
Many news stories about battery fires are actually about smaller e-mobility devices, such as motorized scooters and bikes. The risk, however, is that higher energy batteries with more cells are at greater risk of failing. EV and plug-in hybrid vehicles have about 1,000 times more cells than an e-bike.
Are EV fires more dangerous than ICE fires?
Electric cars catching on fire can be more dangerous than gas car fires if drivers do not understand the unique risks and characteristics of a Li-ion battery fire. EV fires differ from other fires in many ways, including:
- Pack design: As the individual lithium-ion cells experiencing thermal runaway are contained within several layers of metal casings, it can be almost impossible to aim water directly onto the source of the fire (EV FireSafe).
- Thermal runaway: When a Li-ion battery is damaged, a chemical reaction known as thermal runaway can start inside the battery cells. EV batteries then heat up uncontrollably and can be prone to igniting or off-gassing, which can lead to an electric car exploding.
- Toxicity: EV fires produce toxic gases such as phosphoryl fluoride (Scientific Reports), hydrogen fluoride, and hydrogen chloride (EV FireSafe).
- Heat: According to the U.S. Fire Administration, electric vehicle fires can reach temperatures of thousands of degrees. Applying water or foam may cause a violent flare-up as the water molecules separate into explosive hydrogen and oxygen gases.
- Duration: Even after an electric car on fire is extinguished, there is a chance the battery is still in thermal runaway and will reignite hours or even days later. This makes Li-ion battery fires more dangerous than conventional fires.
What Research Shows about EV Fires
Li-ion battery fires spread fast and can reignite later
In one study, when an electric car caught fire, it caused an explosion powerful enough to engulf not only the initial electric vehicle but also the EV next to it. Meanwhile, research by EV FireSafe, a private company sponsored by the Australian government, shows 13% of vehicles studied caught fire following initial suppression, sometimes reigniting multiple times over a period of several hours.
Prolonged charging increases the risk of plug-in electric vehicle fire incidents
Of all electric passenger vehicle battery fire incidents studied, approximately a third went into thermal runaway while connected to AC or DC EV charging, or within an hour of being disconnected from AC or DC EV charging (EV FireSafe).
Auto manufacturers must provide more information in their emergency response guides
A report by the National Transportation Safety Board (NTSB) found that auto manufacturers’ emergency response guides have insufficient vehicle-specific information on how to minimize risks to firefighters and tow operators during high-voltage lithium-ion battery fires.
Government agencies need more safety standards and research on EV fires
NTSB’s report also identified a lack of education and research on stranded energy in EVs and the risk for reignition in high-severity crashes that damage high-voltage lithium-ion batteries.
Electric Car Fires in Florida
In recent years, news outlets have often reported on electric vehicles catching fire in Florida. The comparative frequency of electric vehicles exploding in Florida compared to other states can be traced to the frequency of hurricanes and flooding. For example, there were at least 21 incidents related to EVs catching fire in Florida after Hurricane Ian in September 2022.
What conditions contribute to electric cars exploding in a flood? When EVs batteries are submerged in saltwater, salt bridges can form within the battery pack and provide a path for short-circuit and self-heating. After saltwater flooding from hurricanes, EV owners may think their car is undamaged when the battery has actually corroded. This causes EV fires to erupt days or even weeks after the storm.
Guidance for EV owners in Florida
With evidence of electric cars exploding in Florida following flooding, car owners should follow the U.S. Fire Administration’s recommendation and keep EVs at least 50 feet from any structures, other vehicles, or combustibles if flood water breached the body of the vehicle The Florida Department of Highway Safety and Motor Vehicles requires that vehicle titles disclose when a car has been flood-damaged, mitigating car owners’ risk when buying an EV.
Expert Recommendations for EV Fire Prevention
More organizations are offering online resources about proper firefighting techniques for EV fires. The U.S. Fire Administration outlines best practices for first responders in case an electric car catches fire, while the National Fire Protection Association (NFPA) offers training courses for firefighters.
The NFPA also maintains a collection of emergency response guides from alternative-fuel vehicle manufacturers. These guides include information on how to fight EV fires and hybrid fires for specific car models.
The Future of EV Safety and Fire Prevention
Despite the chances of EVs catching fire, electric vehicles can be safer than gas cars if EV owners, governments, and automakers take necessary precautions. EV owners should avoid overcharging and, if living in a flood-prone area, follow public safety guidelines for keeping EV batteries safe from water damage.
Governments need to provide first responders with training and resources as well as develop standards for EV-specific firefighting methods. Importantly, government funding should also support new technologies that move beyond Li-ion batteries and their flammable components.
Auto manufacturers should continue to improve EV safety technology like battery management and thermal management systems. Ultimately, the best way to avoid electric vehicle fires is to adopt a safer alternative to Li-ion batteries. Learn more about how Alsym’s revolutionary technology can steer our world toward safer electric vehicles.
