If you have flicked through any social media recently you cannot have failed to see the concerns surrounding lithium-ion batteries and electric vehicles.
In the instances of fires caused by e-bikes, e-scooters and disposable vapes the concerns regarding lithium-ion battery safety are well founded. There is not a day that seems to go past without a fire, resulting in severe damage to property, personal injury or tragically death.
For e-bike and e- scooters the guidance is clear, do not leave them to charge unsupervised, do not charge overnight and if possible do not charge indoors. If there is no alternative to indoor charging, ensure the equipment being charged is not blocking a safe exit route.
However, for electric vehicles the situation is more complicated, and the available data is harder to accurately assess and analyse. As a result of this society seems to have polarized itself into taking extreme views reading the safety of EV and ICE’s. The extreme pro EV camp believes an EV can do no wrong and poses minimal risks when compared to and ICE vehicle. The extreme anti EV camp believe lithium-ion battery vehicles are mobile time bombs waiting to explode at any minute.
For the purpose of this article, I would like to focus on the sensible “middle ground” on which we should base any risk assessments and also to dispel some of the common myths regarding both EV’s and ICE vehicles as both for and against camps try to play one vehicle type off against the other.
Setting the scene
When we look at the nature of ALL vehicle fires, we have to understand that in the last 20 years car design and the materials used for car construction have changed significantly regardless of whether they are EV’s or ICE’s. ALL vehicles now contain far more electronic components and volatile synthetic materials than ever before.
The use of these materials means that ALL cars will burn more fiercely than they ever did before in the event of a fire. The intensity of a modern-day car fire means that any vehicle fire will spread more quickly either from vehicle to vehicle, or to surrounding infrastructure. The use of more volatile materials will also mean that ALL modern cars will give off more toxic fumes and result in the creation of highly polluted fire water run-off.
These facts are confirmed from feedback from firefighters and first responders tackling car fires globally. ALL modern cars now take longer to extinguish and require more water than they ever did before.
At EV-EXBOX we look at the typical risks associated with both EV and ICE vehicles, and we find that in many respects they are pretty similar.
A petrol car has the inherent risk of fire, a release of explosive fuel vapour, emitting toxic fumes and creating a serious pollution event. Likewise, an EV car can catch on fire due to thermal runway, emit explosive and flammable vapour in the form of electrolyte gasses, emit toxic fumes and result in a pollution event. With this in mind we struggle to understand why the design of EV charger locations are not as onerous or well defined as those for petrol filling stations when the risks attributed to both EV’s, and ICE’s is comparable.
Myth 1 - EV’s catch fire less than ICE’s
To begin with we need to understand that the frequency of EV fires compared to ICE fires is very difficult to record with any degree of accuracy on a global basis. To date I have seen figure published that state, “You are 24 times more likely to been involved in an ICE fire than an EV fire” or, “0.3% for EVs cars caught fire globally compared to 1.05% for ICE cars”.
The problem we face as an industry going through a huge transition is we still do not have enough data to make a true statistical comparison that is meaningful to identify the differences between the fire frequency of EV’s and ICE’s.
The challenge with the current data is the huge disbalance in the numbers of EV’s vs ICE’s. Just reporting the numbers is not enough. For a truly accurate analysis we must consider vehicle age profiles vehicle type, vehicle use, vehicle power, vehicle mileage, vehicle usage, frequency of servicing, previous crash history etc…. with regards to both the EV and ICE vehicles in the data set.
Thankfully there is some great work currently being undertaken by, EV Fire Safe in Australia and the Dutch Institute for Safety, (NIPV), and with time, (probably at least another 10 years), we could have enough data to compare EV fire frequency with ICE vehicle fire frequencies using truly comparable data sets.
However, maybe we should even challenge the relevance of the EV vs. ICE comparison, especially when a lot of new ICE vehicle manufacture stops 2030-5. At some point we will reach a tipping point in the balance between EV’s and ICE vehicles and in another 20 years, we may only have EV fires to worry about.
As we clearly understand the fire risks of ICE cars surely it is better to just focus our attention to EV and hybrid data to assess where, when, and how they catch fire. If you believe the current data that EV’s catch fire less, then let’s understand why they burn at all and, try to eliminate this through design of both vehicles and charging infrastructure. If we can do this, we achieved something meaningful through the data analysis for the future safety of EV’s.
Myth verdict – stop comparing EV and ICE fire frequency it will be an ever-moving target. What is inevitable with any mechanical device is the risks of failure resulting in fire increases with usage and time. If we add to this our demand for more powerful batteries and faster charging the problem will grow but hopefully be balanced by some advances in battery technology. As we move to battery storage systems within charging poles, we must now also consider not just the EV’s but also the charging infrastructure supporting them.
EV fires are more difficult to extinguish than ICE fires
With the true unknown probability of an EV or ICE fire set to one side we should perhaps focus on what happens when we do have a vehicle fire, (already knowing that all car fires are harder to deal with than they were 20 years ago). For ICE cars the emergency services have had over 100 years of practice in extinguishing fires, so the risks are known, the training is in place and the equipment carried is fit for purpose.
For EV’s there is more of a challenge as the emergency services and the entire fire industry is still innovating to try and make lithium-ion battery fire suppression in vehicles more effective. The biggest challenge still sits with the car design itself where the battery packs are very inaccessible and, by design, waterproof. The secondary challenge is that the exothermic reaction that is,” thermal runaway,” does not behave like a traditional ICE fire.
A lithium-ion battery in thermal runaway emits highly flammable and explosive gas. When the gas ignites there can be a vapour cloud explosion or the violent burning off of the electrolyte gas as it is released from the battery pack. But is that not the same as petrol vapour which can explode and burn as well?
In some ways the answer is YES, however, with a petrol fire once you starve the fire of oxygen or remove the vapour you have effectively controlled the fire. With a lithium-ion battery fire starving the fire of oxygen can be challenging as the battery creates its own oxygen during thermal runaway. What you may do during an EV fire is extinguish the flames that were the result of all the burning volatile organic materials, plastics, rubber etc…. but the thermal runaway in the battery will continue. As long as the thermal runaway continues the battery will continue to emit flammable and explosive gas and so we enter the cycle of EV fire re-ignition, which can persist for days.
Myth verdict – Yes in today's world an EV presents a bigger challenge to firefighters than an ICE vehicle due to the nature of a lithium-ion battery fire. Aside of the battery the burn characteristics of an EV and ICE are pretty much the same.
An EV fire creates a bigger environmental incident than an ICE fire
What you will often hear regarding an EV fire was the fact that tens of thousands of litres of water had to be used. This is often the case and sometimes the EV can end up in a total submersion container. When we look at the volumes of water used, we should ask ourselves how much of this water was used effectively?
All cars will create highly toxic fire water pollution; however, an EV vehicle fire will create a harder fire water pollution event to control if we put excessive amounts of water on it. The release of pollutants from an EV becomes worse than an ICE car if the battery pack splits and is flushed as part of the firefighting process.
When we look at innovation the key to controlling an EV fire is around cooling the battery as this slows down and eventually stops thermal runaway. Simply turning a fire hose onto the battery and using water alone may not be the best use of such a large volume of water. New equipment on the market allows the battery to be punctured or cut into allowing the battery compartment to be flooded with water. The difficulties with this arise with locating the best place to create a successful battery penetration. We have to consider all the various differences between the makes and models of EV’s. In terms of personal safety directly trying to access the battery pack puts the emergency services closer to the burning vehicle. If battery penetration can be successfully achieved then yet less water will be used, however, as we mentioned before if the battery pack is flushed then this will result in the highest release of toxins into the firewater.
The biggest challenge with any EV fire on a forecourt of EV hub is very little thought has been given to controlling the firewater itself. As EV charging is sited as far away as possible from hazardous refeulling zones it gets pushed to the boundary of the site where all the run off typical goes straight to surface water and storm drains and therefore straight into the environment.
Having reviewed a number of high-profile ship fires recently, (and let’s not debate if it was EV or ICE until the investigations are completed), it seems innovation is now looking at water misting as a more effective cooling solution than water drenching. Water misting using an added encapsulation agent to promote rapid cooling may take us even a step further in the effective suppression of a thermal runaway event using less water.
Myth verdict – all modern cars create more toxic firewater and smoke than they ever did before which has been overlooked in terms of pollution control mechanisms where any cars park or are charged. The EV has the potential to release more heavy metals and PFA chemicals if the battery pack is flushed. The use of excessive amounts of water used to combat EV fires will make the EV firewater run off harder to contain. The installation of fire water pollution valves at the final point of discharge for forecourts, EV hubs and carparks could be the best way of protecting our already seriously polluted rivers and waterways.
There are fire extinguishers for lithium-ion battery fires
When we consider risk assessment, we cannot ignore the behaviours of the public and how they interact with our safety systems. For a petrol spill they may grab a sand bucket and happily throw its contents over a spill. In a fire they might grab a fire extinguisher as they are typically located next to the pumps, and we are happy for them to do that. So, what does a customer or site operator do in the event of an EV fire?
On the marketplace today there is an array of fire extinguishers that are suitable for some lithium-ion battery fires, but not all of them. A typical fire extinguisher may contain between 9 – 50 litres of firefighting medium. This may be enough for laptops, phones, e-bikes, or mobility scooters but it will have no effect on an EV battery fire. There is simply not enough medium to cool the battery and probably not even enough to extinguish all the synthetic materials once they are fully alight. It is important to remember a lot of EV charging is unmanned and unsupervised so a fire may be well established before any alarm is raised and action taken.
Myth verdict – there is no fire extinguisher suitable for an EV battery fire. The desire of an EV driver to save his own vehicle should not be encouraged through the use of fire extinguishers, leave it to the professionals.
A fire blanket will put out an EV fire
If we look at fire blankets then the application of these is really a job for between 2-4 people, not an individual.
Once of the key challenges in deploying a blanket is you need to get close to the vehicle and the EV can jet out flames from the battery pack up to 2-3m. If the fire is within a hybrid or petrol car there is the risk of explosion fuel vapour as well.
If a fire blanket is successfully deployed it can extinguish the flames associated with the synthetic material components of the car through oxygen starvation. However, as discussed before, the battery can generate its own oxygen and if not cooled it will continue to emit highly flammable electrolyte gas. To smother a fire the fire blanket must be impermeable so therefore you can run the risk of allowing the explosive electrolyte gas and toxins such as hydrogen cyanide and hydrogen fluoride to build up under the blanket.
Myth verdict – At EV-EXBOX we have seen fire blankets deployed at EV charging hubs and in car show rooms which makes us very nervous. What we know about EV fires is they should only be tackled by the emergency services who will be fully trained and wearing breathing apparatus and fire-retardant clothing. The desire of an EV driver to save his own vehicle should not be encouraged through the use of fire blankets. Fire blankets do have a role to play in vehicle firefighting but please leave this to the professionals.
EV’s are heavier than ICE’s creating a problem for the future
For now, let’s forget the EV vs ICE debate and just focus on cars in general. ALL cars are getting heavier for two main reasons. First, people want a much higher equipment specification, more luxurious seating and bigger interiors for more space and comfort. There is also the perception that bigger is safer although ironically heavier means harder to stop and slower to escape from a potential accident scenario.
The rise of the SUV and uptake of 4x4’s in urban areas means average car weights have been increasing for some time, with or without the uptake of EV’s. Yes, an EV battery can weigh over 500kgs but most EV’s are weight comparable to most small non-EV SUV’s. The real weight factor only really comes into play when you put massive batteries into massive cars which tends to be at the more luxurious end of the car market and therefore, they are typically less common.
Myth verdict - Our obsession with owning bigger vehicles in general is the issue. Heavier cars could pose a problem for some very old structures as time goes on, but this is not uniquely an EV issue. If we think there is unfair wear and tear on roads then use weight as an additional taxation metric, let’s face it the vehicle taxation metrics have changed at least twice in my lifetime which means they are not fixed.
Conclusion
In a world where we are still struggling to understand the long terms risks of EV’s we must firstly acknowledge the fact that EV’s and modern ICE’s have both brought new challenges to public, fire and environmental safety management and risk assessment. Much of our infrastructure today has not taken into account how these risks have changed over the last 20 years. If we look at a petrol filling station with EV charging the risk profile is still really focused on the hydrocarbons and not the EV facility. If we look at an EV only charging facility the design typically ignores all of the common risks shared by both EV’s and ICE’s namely fire, risk of explosion and an increased toxicity of firewater run-off.
In this article we have covered some of the most common challenges, but the list goes on and gets infinitely more complicated in locations such as below ground and multi-story carparks. Additional considerations must also be given to public safety as EV chargers are now located in areas where there can be a high concentration of people such as shopping centre carparks. As EV charging is pushed to the boundaries of petrol filling stations then boundary risk assessments should consider the risk of adjacent material flammability such as cladding and the risk of fire spreading through wooden fencing or landscaped areas.
Having watched the electric vehicle and clean energy transition for many years EV-EXBOX have devised a range of sensible and cost-effective risk assessment services, fire suppression and firewater pollution control measures to mitigate risk across a wide range of premises.
We are ALL on a learning curve when it comes to understanding the risks differences between ICE’s and EV’s as the clean energy transition gathers pace. Do not be afraid of the risks but equally do not be complacent or ignore the risks either. Our industry has been at the forefront of designing out risks and it all starts with sensible risk assessment. If safety itself starts with a conversation please reach out to the EV-EXBOX Team to discuss how we can help you to mitigate the risks of fire, public safety and environmental pollution for the future on any EV charging facility or location.
Email info@ev-exbox.com www.ev-exbox.com
Commenti