Putting Out Fires in Electric Cars

Time and again you hear in the news about burning electric cars, especially the models of a well-known American manufacturer that have made headlines several times. The burning car carrier "Fremantle Highway" in the North Sea off the Dutch islands in mid-2023 also demonstrated once again how dangerous a fire in an electric car can be. This is less about the frequency of fires in electric cars (numerous studies show that E-cars do not catch fire more often than petrol cars) and more about the particular challenges that a burning electric car, in particular the lithium-ion battery contained inside it, poses to firefighters and other first responders, and how extinguishing often proves extremely challenging.

Putting out electric cars – the most important information in brief

The batteries in modern electric cars can store enormous amounts of energy and the fires that occur there must be fought differently than those of conventional internal combustion engines. Special extinguishing measures are required; currently, large quantities of water are often used, but for efficiency and lower effort, for example the use of fire blankets for electric cars is more effective. Fire blankets can also be used where large amounts of water are not available or would cause damage to the surroundings (such as underground garages, parking garages). Special caution is required with the subsequent disposal of the electric passenger cars. A similar issue – though due to the much smaller batteries – also affects plug-in hybrids and hydrogen-powered cars, which are also equipped with Li-ion batteries.

Here you can go directly to the most important extinguishing agents for electric cars:

=> To the fire blankets / fire containment blankets for electric cars

Detailed information on extinguishing electric cars can be found in the sections below.

• Lithium-ion batteries in EVs are the greatest fire hazard
• How to recognize a possible fire in an electric car?
• Extinguishing burning electric cars
• Special case: Extinguishing EV fires in parking garages and underground garages
• After the fire is out: disposal of Li-ion batteries
• How to extinguish plug-in hybrid and hydrogen cars?
• Electric cars with novel LFP batteries - less prone to fire

Batteries in EVs are the greatest fire hazard

Unlike a traditional petrol engine, pure electric cars do not carry fuel in the form of gasoline or diesel (plug-in hybrids / PHEV do, in contrast), so in the event of an accident the fuel cannot ignite in an EV. The danger in an electric car comes from the high-performance battery installed, which in newer models can store large amounts of energy to enable the desired range for customers.

Initial note: Electric cars are not more dangerous than conventional combustion engines

It is important to note here that the aim is not to convey the impression that electric cars are more dangerous than conventional cars. With the increasing spread of alternative drives, the requirements for efficient extinguishing management simply change, especially for fire brigades. With the necessary preparation and consideration of the new framework conditions when extinguishing electric cars, the fire department and also private individuals are just as well prepared for this new situation as for possible fires of classic passenger cars and trucks.

Li-ion batteries are fundamentally well protected

The Li-ion batteries used in electric cars are typically integrated very well into the bodywork by manufacturers and enclosed, so the individual cells are encapsulated to provide a good base protection for the batteries in the cars. Nevertheless, in accidents there can be such strong forces that individual cells or the entire battery area may be damaged, leading to different consequences, up to the fire of the electric car.

How to recognize a possible fire in the electric car?

Unlike a classic car fire, a burning battery in an electric car typically does not show flames leaping up immediately, but begins with a thermal reaction in the battery cells. The temperature inside individual cells rises, spreading to other cells and slowly increasing temperatures, leading to the feared thermal runaway in which many (or all) battery cells react thermally and can catch fire. Early signs of a developing fire in an electric car are:

• Gas leakage from the battery block, often accompanied by hissing, whistling, etc.
• Smoke development near the battery block
• Individual flash flames or sparks, often combined with a corresponding odor
• Rising temperature over a longer period after the accident

Difficulty with time distance to the accident

A difficulty in battery fires in electric cars can be the time distance to the actual accident. Even if the initial fire is extinguished by the fire brigade, a defective battery can pose danger much longer; sometimes even for days.. In individual cases burning EVs must even be submerged in water-filled containers to control the long-lasting thermal reaction of Li-ion batteries.

Extinguishing burning electric cars

Conventional extinguishing agents or ordinary car extinguishers are only marginally suitable for extinguishing electric cars. If there is a fire in electric cars or trucks, the operation of the fire brigade is unavoidable, because the electrical systems and the batteries pose significant hazards to life and limb.

Professional firefighting essential

Special battery fire extinguishers are mainly to be viewed as a supportive measure, whose effect for EVs, battery forklifts, etc. is rather limited and therefore their use is not recommended - professional help is essential here, just like when extinguishing PV storage / battery storage fires. Accordingly, extinguishing electric cars focuses on two areas: containing the fires and protecting the surroundings by cooling the battery. While for extinguishing fires a blanket is used by more and more fire departments for EVs, the efficient and primarily long-term cooling of the EV battery remains a major challenge. Finally, the defective batteries or the entire EVs must be transported from the scene for disposal - another difficulty for many professional firefighters.

Real "extinguishing" of electric cars not possible

A peculiarity of lithium-ion batteries and thus of electric cars is that you do not extinguish the fire in the conventional sense (as with a regular fire), but due to the construction of the batteries the fire can flare up again for a long time (therefore EVs are also submerged in containers after extinguishing, so the battery can "cool down" for a long time). Accordingly, firefighting for electric cars mainly involves containing the flames, and the blankets are not fire blankets in the strict sense, but fire containment blankets. Nevertheless, colloquially this is also referred to as "extinguishing."

Measures for extinguishing electric cars

The following sections explain, with which measures professional firefighters extinguish electric cars and what post-extinguishing measures are necessary:

• Current extinguishing method for EV fires: a lot of water
• Fires of electric cars with fire blankets / fire containment blankets
• Battery fire extinguishers as a first measure
• After extinguishing: removal and cooling of the electric car

Currently commonly used by fire departments: a lot of water

Currently the fire brigade often uses a familiar and proven method: water. On site, however, they extinguish not only the acute fire, but due to the special properties of a battery the extinguishing/cooling must be ongoing, so several ten thousand liters of water may be required for a single electric passenger car.

Difficulty: limited onboard water supplies of fire engines

Here a problem arises: since the rescue vehicles carry only limited amounts of water, supply from a hydrant is necessary. Even large rescue vehicles typically have no more than 1,500 liters of extinguishing water or extinguishing foam on board. If a hydrant is not immediately available nearby, extinguishing an EV can become a logistical challenge. For example, extinguishing an EV on a highway, where hydrants are often unavailable or rare, can be a logistical challenge.

Special extinguishing lances to make extinguishing more efficient

To make extinguishing electric cars even more efficient, various providers are developing systems designed to reduce the required water. With specially developed lances for battery fires or complete extinguishing systems, one aims to quickly and efficiently tackle the fires. However, these extinguishing systems are often costly and tied to a specific vehicle technology, which is not available on every response vehicle.

“Cooling basins” for electric cars – water-filled containers provide long-term safety

What was previously known only from nuclear energy contexts, the so-called cooling basin, in which residual heat can be released over a long time, is also often used for sustainable extinguishing of EVs. Specially prepared containers are filled with water and cars are submerged there to deprive the battery of any chance to develop another fire. As an alternative to the water-filled extinguishing containers, there is another system, such as a configurable Recover-E-Bag storage system, which is much more mobile and easier to use.

Conclusion: Conventional measures for burning electric cars are only partially sensible/available

As the above explanations show, classic methods of firefighting reach their limits with high-energy batteries, so at least for initial actions, alternatives should be considered. More and more fire departments are turning to special fire blankets for EVs, with which battery fires can be contained very efficiently without huge amounts of water, gaining valuable time to initiate further measures and minimize acute environmental hazards.

Fires of electric cars with fire blankets / fire containment blankets

Fire blankets for electric cars are an effective way to contain burning lithium-ion batteries and minimize the hazards from a burning lithium battery. The method is simple and ingenious: by spreading the blankets over the burning or fire-hazard EV, the fire-suppressing material of the blanket prevents the battery fire from spreading to the surroundings. Accordingly, the blanket does not extinguish the battery fire in the literal sense, but prevents the spread of the fire and prevents larger damage. Manufacturers such as JUTEC, VLITEX and BRIDGEHILL offer a range of fire blankets / fire containment blankets for these applications.

• To the JUTEC fire blankets for electric cars
• To the VLITEX fire blankets for electric cars

Flare-ups and spread to the surroundings are prevented

The cause of the fire, often a so-called thermal runaway in the defective Li-ion battery of the EV, cannot be extinguished by the blanket, but using a fire blanket prevents open flare-ups and simultaneously minimizes damage to the surroundings. At the same time, the blanket deprives the fire of oxygen, which further has a firefighting effect.

Fire blankets buy time for further countermeasures

In principle, the blanket provides a "safe" environment where the battery fire cannot cause further environmental damage, giving enough time to initiate additional countermeasures. For EVs this can also mean storing them in extinguishing containers until the Li-ion battery-generated danger is fully contained.

Securing removal with a fire blanket

Fire blankets are used not only for active firefighting but also as a sensible safety measure when transporting a damaged EV—even if there is no active fire. If there is a risk that the car battery may ignite, a fire blanket can be used preventively during transport of the damaged EV.

Fire blankets as quarantine measure for damaged EVs

After an EV accident, these cars are usually stored at the mishap site of a towing company or workshop to minimize the risk of later battery fire. Fire blankets can also be used as a quarantine measure to store EVs securely for longer periods. The advantage over water-filled containers is, on one hand, the lower price, and more importantly, the EV is not damaged under the blanket.

Fire blankets versus fire containment blankets?

Colloquially, blankets used to contain / limit fires are usually referred to as fire blankets. Strictly speaking, the blankets presented here do not extinguish EV fires but contain them or prevent further spread. Therefore, fire blankets are officially called fire containment blankets rather than extinguishing blankets. For easier understanding, both terms are used interchangeably here.

Possible first measure for private individuals

Fire blankets, as described above, are well suited to contain an EV fire. In an early phase, they can even be a possible first measure for private individuals. If there is suspicion that the car battery poses a danger, you can drape a fire blanket over the car and call the fire brigade, who will take over professional suppression. For operators of underground garages and parking garages, such a blanket can prevent damage to the building/structure if available on site, because the new generation of fire blankets is not only relatively light but can also be pulled over the fire source by laypeople after a brief briefing. Always keep in mind never to put yourself in unnecessary danger.

Fire extinguishers not suitable for extinguishing electric cars

Contrary to some circulating information, in our view battery fire extinguishers are not suitable for extinguishing electric cars. The extinguishing agent contained in the extinguishers has no effect due to its small volume. Moreover, the battery in an EV cannot be reached from outside. Also, people put themselves at great risk due to heat, smoke development, and the potential for a deflagration. If an EV catches fire, you should revert to fire containment blankets etc. or - for private individuals often the best option - call professional help and leave firefighting to the fire department, which usually has the appropriate equipment and training.

After extinguishing: safe removal of the EV and cooling of the battery

Extinguishing the EV does not completely eliminate the danger, because a high-performance battery can flare up again later. Therefore, special safety measures also apply to removal. Many fire departments or specialized service providers use the containers described above to submerge the EV. VLITEX now offers with the Car Service Set an option to transport accidented EVs on conventional tow trucks by completely wrapping them in an appropriate fire blanket.

Long-term cooling of Li-ion batteries during extinguishing and afterwards

Due to the enormous thermal energy in the lithium batteries, long-lasting cooling of the cells is the top priority during extinguishing—naturally after all safety distances and necessary precautions regarding electrical systems are observed. If the EV caught fire while charging—the charging of batteries is always a critical moment when hazards can arise—of course the charging cable must be removed beforehand to avoid adding more electrical energy to the system.

Storage of defective EVs in water-filled containers

What may sound odd at first, is practiced frequently: after initial extinguishing and acute firefighting, EVs are stored in specially prepared containers in a water bath for several days. There the thermal reaction of the battery can be completely stopped.

Sonderfall: EV fires in underground garages or parking houses extinguished

With the increasing spread of electric cars and plug-in hybrids, a whole new problem arises: if the fire brigade cannot approach the burning EV directly, mobile extinguishing aids such as fire blankets become increasingly important. In more and more parking garages or underground garages it is therefore no longer allowed to charge or even park electric cars.

Special fire blankets for electric cars in fires in underground garages and parking houses

The mobile fire blankets for EVs offer an optimal way to contain the fire in otherwise difficult-to-extinguish EV fires in garages and parking houses. Normal fire engines cannot drive to the fire source in these situations, but the fire blanket can be carried by two firefighters to the electric car and pulled over the fire source. Immediately, further spread is prevented and the greatest danger is contained, and the building material is not endangered by the EV fire.

When the fire is out: disposal of defective Li-ion batteries

After extinguishing the fire, the lithium battery still needs to be disposed of properly. For transport to the disposal company, appropriate battery transport containers are required. Due to the size of the batteries and their condition (the batteries are considered defective and are sent for recycling or disposal), only packaging group 1 transport containers can be used for this purpose.

How to extinguish plug-in hybrid vehicles and hydrogen cars?

As mentioned above, the capacity of a built-in battery is directly related to the potential danger, because the larger the energy stored in a battery, the greater the possible consequences in a thermal runaway or battery fire. This does not mean that plug-in hybrids (PHEVs) or hydrogen-powered vehicles are not affected by this issue.

Extinguishing plug-in hybrid vehicles - a combination of fuel and battery fires is possible

If a PHEV catches fire, you are likely dealing with two different fire causes: on the one hand the fuel can burn (gasoline/diesel), so you can apply the traditional extinguishing measures. Often, the battery is also affected, so after extinguishing the conventional fire you should switch to battery-fire extinguishing measures – possibly even preventively to rule out the possibility of a battery fire from the outset. Although Li-ion batteries in PHEVs are much smaller and less powerful than those in full-electric cars, they still have enough capacity to cause significant damage. From the firefighters’ point of view, PHEVs are therefore actually more problematic than pure electric cars due to the combination of fuel and battery fires.

Hydrogen-powered vehicles – only relatively small buffer battery on board

Unlike the electric car or PHEV, vehicles with hydrogen propulsion have only a relatively small battery on board, which is used only to temporarily store electrical energy. The actual energy carrier is hydrogen, which is converted to electrical power in the fuel cell during operation and then provides propulsion in the electric motor. With this comparatively small buffer battery, hydrogen cars pose only a minor danger. The carried hydrogen also presents only minimal danger due to the high-security tanks used; even in extreme situations, crash tests have shown that hydrogen does not escape uncontrollably and does not ignite. From the fire department’s perspective, hydrogen-powered drives are therefore the easiest cars to extinguish.

Electric cars with novel LFP batteries – less prone to fire

Lithium iron phosphate batteries (LFP batteries) have gained popularity in recent years, especially due to their safety features. One main reason why LFP batteries are considered safer, particularly regarding fire risk, lies in their chemical composition and thermal stability. Accordingly, they are increasingly used in EVs, so that the fire hazard from batteries of these models is lower.

What is the difference between LFP and lithium-ion batteries?

LFP batteries use lithium iron phosphate (LiFePO4) as the cathode material. This chemical is thermally more stable than the materials used in conventional lithium-ion batteries, such as lithium cobalt oxide (LiCoO2). This higher thermal stability means that LFP batteries are less susceptible to overheating and have a lower likelihood of undergoing thermal runaway – a state in which battery cells generate heat uncontrollably and pose a fire risk.

Lower energy density – advantage for safety, disadvantage for range

Moreover, LFP batteries have a lower energy density than conventional lithium-ion batteries. This may initially seem like a disadvantage, especially in EVs, but it actually contributes to safety. The lower energy density means less energy is released in the event of damage or malfunction, reducing the risk of rapid ignition or explosion.

Longer lifespan and many charge cycles

Additionally, LFP batteries are characterized by a higher number of charge cycles and longer life, making them more economical in the long term. They are more environmentally friendly as they do not contain cobalt, a metal often mined under problematic conditions.

Increasing use in electric cars

Lithium iron phosphate batteries (LFP batteries) are also used in electric cars. In recent years they have gained in popularity in the electric vehicle industry, mainly due to their safety advantages, longevity, and also due to their lower cost. Many EV manufacturers see the benefits of LFP batteries and increasingly integrate them into their vehicle models, especially for models designed for efficiency and safety.