With Australia and New Zealand plans to accelerate the sales of electric vehicles (EV) over the next decade, emergency services are steeling themselves to fight a completely new set of fire risks that will emerge as EVs become more popular.
How big is the possible EV fire issue?
Sales of electric and plug-in hybrid vehicles surged in Australia over the first half of 2021. Their combined market share about doubled compared with last year’s tally.
Some 7,248 electric vehicles (EV) were sold in Australia between January and June, according to the latest Electric Vehicle Council market report, in addition to 1,440 plug-in hybrids (PHEV).
These combined 8,688 sales equalled 1.57% market share, up from 0.78% share in 2020. Strip out light commercials and it’s 2.0%. More EVs were sold in the first half of 2021 than all of 2020.
The demand for electric and hybrid vehicles is looking to increase significantly in 2022 and beyond with all major car makers having Electric and Hybrid cars in their range. With the change of government policies and tax incentives the ‘green’ vehicle market will be seen to grow exponentially.
With this growth Emergency Services will have a completely new set of fire risks to deal with as EVs and plug-in hybrids (PHEV) become more popular.
What is different about EV fires?
Lithium-ion batteries are a popular technology for electric vehicles because they store a huge amount of energy in a very small space. The individual cells in a lithium-ion battery can be damaged in the event of a traffic accident especially from a side impact or if there is a fire in the car. If the battery is exposed to excessive heat, or there is a penetration in the battery case, then an internal short circuit causes heat that triggers a chemical reaction and a process called thermal runway, which can lead to ignition. Such incidents can be extremely dangerous and produce intense fires, which burn even without oxygen and cannot be quenched by a traditional fire extinguisher, often requiring many thousands of litres of water to just contain the fire. If an Internal Combustion Engine (ICE) vehicle catches fire after an accident, it usually happens quickly and is very evident.
These increased risks now pose a huge challenge to the Fire and Rescue Services and first responders when attending any vehicle fire, and new robust procedures are now required when dealing with any incident. Fire and Rescue services across the world are working hard to improve their knowledge and understanding of lithium-ion battery fires and reviewing their current procedures to see if they are adequate to deal with the risks as the number of EVs on the roads continues to grow.
The issue
Although these fires remain rare, when they do occur, they can be extremely dangerous. During an electric vehicle fire some incredibly toxic gases such as carbon monoxide and hydrogen cyanide – both of which are fatal to humans – are created. For the fire and rescue services this means that responders must wear full PPE with respiratory equipment when dealing with any sort of vehicle fire. Putting out an EV fire demands around 1,125 litres of water a minute. Independent research and information for first responders produced by Tesla warn that a battery fire in an electric vehicle can take up to 60,000 litres of water and up to 24 hours to fully suppress. Water also can become contaminated with soot and chemicals and run-off into public drainage systems.
Three key safety risks with lithium-ion batteries
Thermal runaway
Each cell in a lithium-ion battery contains a flammable liquid electrolyte. If the cell short-circuits, the electrolyte can combust; pressure in the cell then rapidly climbs until the cell bursts and vents the flammable electrolyte. Temperatures of the ruptured cell can increase to above 1,000°C. The rapid and extreme rise in temperature (thermal runaway) can easily pass to nearby cells in a domino effect that is called thermal runaway. Thermal runaway generates smoke, fire and explosions.
Battery re-ignition
Re-ignition of a damaged battery pack can occur at any time, post-fire damaged cells can heat up once again if cooling has not been sufficient. Also when moving a vehicle damaged cells can move and short-circuit and reignite the battery pack. This may not necessarily lead to problems if the fire service is present, but it is a great risk to car-towing companies or storage yards. There have been incidents when a battery pack has reignited during towing and after having been stored at a workshop/scrapyard.
Stranded energy
Stranded energy is defined as the energy remaining as stored energy in a damaged lithium-ion battery. The stranded DC energy within the damaged lithium-ion batteries is a significant fire and shock hazard to emergency responders. This is an unresolved issue as there are no procedures to remove the hazard of stranded energy and safely neutralize the batteries.
Extinguishing EV fires
Fire and rescue services basically have two main options, let the fire burn out (Defensive) or extinguish it (Offensive). The obvious choice seems to be to extinguish the fire, but many EV manufacturers actually advise a controlled burn.
Defensive firefighting
This is where the fire and rescue services allow the vehicle to burn out while they focus on protecting the surrounding area. Letting a fire burn out is not an ideal solution as it can impact on the surrounding environment, property and people. A battery fire may continue for several hours and may result in multiple flare-up events due to the way thermal runaway propagates throughout the battery. It also can mean closing a road for many hours, significantly disrupting communities and businesses, which may rule it out as an option.
The potential difficulty is having and applying a sufficient amount of extinguishing agent to a burning high-voltage battery, and the incident commander may allow the vehicle to burn itself out.
Offensive firefighting
If the Electric Vehicle battery is involved in the fire, an offensive attack may be recommended if there are exposures (other vehicles, buildings, etc.). Large amounts of water are required, and the water does not supress the thermal-runaway reactions within the battery pack but cools the cells and controls the spread of fire. A battery fire may continue for several hours and it may take 24 hours or longer for the battery pack to cool after it has been fully consumed by a thermal-runaway event.
Removing the vehicle
A battery fire may continue for several hours causing the closure of major roads and motorways. To minimise these major road closures it might be decided to remove the vehicle. This is why some brigades in Europe have developed a storage container to remove the vehicle from the incident.
The container is constructed in such a way that you lift or tow the vehicle into it, place the container on the bed of a tow truck and remove the vehicle. The container is sealed and filled with water to extinguish any flames and cool the battery. The vehicle is then left in the container until the risk of it flaring up has subsided. This was seen at the time to be the most favourable and safest option to deal with lithium-ion battery fires but is very costly to implement.
Guidance
The latest National Fire Protection Association (NFPA) electric vehicle emergency field guide sets out how to handle vehicle fire incidents involving mainstream hybrid and electric vehicles of different brands. It looks at methods to identify, immobilise and disable the vehicle, as well as fire suppression strategy. By summarising different codes of practice in different countries, the recommended EV firefighting process is detailed as:
- Identify the vehicle – by using tools such as the Moditech Crash Recovery System (CRS) accurately identify the correct rescue datasheet. In some instances, the fire rescue centres can request information based on a vehicle’s licence plate to enable firefighters to accurately identify the correct rescue datasheet.
- Determine the firefighting plan based on the situation
- Protect the people first
- Control or extinguish the fire, and if the car is charging, switch off the charging infrastructure, if possible
- Vehicle should not be moved immediately, after the fire is extinguished, certain disposal procedures are also recommended; that is, the EV should be parked in an outdoor place after the accident because of the re-ignition ability of the battery
A new solution to tackle EV fires
The Bridgehill Car Fire Blanket keeps smoke, toxic fumes and flames underneath the blanket away from fire crews and first responders and isolates the car fire. The blanket is deployed over the burning vehicle so the fire can be contained or extinguished. The car fire blanket preventing toxins from escaping into the environment and in many cases, firefighters can avoid using water, which leads to hazardous substances seeping into the groundwater.
The fire blanket is highly effective for both internal combustion engine (ICE) vehicles and Electric Vehicles (EVs). You can gain control of the situation quickly and extinguish an ICE vehicle fire in minutes due to lack of oxygen and contain toxic gases and smoke which are stifled immediately. The same immediate result is achieved in EVs whose batteries have not been affected by the fire.
If on an EV the batteries have been compromised and thermal runaway is occurring, the lithium batteries will continue to burn even without oxygen and will not respond to traditional fire extinguishers. The heat and fire is contained by the blanket for many hours or days until the batteries have extinguished themselves. The car fire blanket is the only proven method of dealing effectively with EV fires and can be used without water. The blanket can also be left in situ on the vehicle whilst being moved or disposed as lithium-ion batteries have been known to reignite many days after being involved in a fire. It is now recommended that an EV vehicle damaged in an accident, even with no fire present, should be stored in the open and away from other vehicles for over 48 hours.
The blanket comes in two versions. The professional Pro X version is a multiple-use blanket for Fire and Rescue services and similar organisations. The standard version is a single-use blanket for locations with a high concentration of cars, such as car dealerships, service centres, parking garages, passenger car ferries and car repair shops.
The Bridgehill Car Fire Blanket (Pro X)
The Car Fire Blanket (Pro X) is reusable for up to 20+ car fires. It is suitable for professional firefighters and other organizations that may have to deal with multiple fires. After use, simply rinse the blanket with water and store it in its smart bag. The Car Fire Blanket (Pro X) is made from a heat-resistant fabric called BridgeTech, using technology pioneered by NASA in the space shuttle programme. It measures 6m x 8m and can withstand temperatures of 1,500˚C for 48 hours. If kept in its purpose-built smart bag or storage cabinet, it carries a lifetime warranty.
Bridgehill also makes a range of smaller blankets designed for distribution centres, workshops and shopping malls specifically for electrical fires in forklifts, open battery packs and small electrical goods powered by lithium-ion batteries.
The Bridgehill Car Fire Blanket (Standard)
The Bridgehill Car Fire Blanket (Standard) is a single-use blanket Ideal for spaces with a high concentration of cars, such as car dealerships, service centres, parking garages, passenger car ferries and car repair shops.
Where to use the Bridgehill Car Fire Blanket
There are many places where a Bridgehill fire blanket should be located in the event of an EV Fire such as parking lots, EV charging stations, passenger car ferries, road tunnels, car dealerships and service centres, car repair shops and car recovery services.
PT Rescue are pleased to announce that they have secured the agency for Bridgehill Fire Blankets who are at the forefront of technology with solutions for lithium-ion battery fires. This product has created great interest across the world with many Fire and Rescue Services using this new car fire blanket with over 5,000 Car Pro X blankets being purchased since 2019.
For more information, email rescue@pthydraulics.com.au
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