Controlling Electric Car Fires Using Containers

Controlling Electric Car Fires

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Controlling electric car fires is one of the biggest challenges facing the fire and rescue service globally.

Whilst EVs are inherently safe and their catching fire is a relatively rare occurrence, the number of EVs on the roads is rising exponentially and so too will the number of electric vehicle fire incidents.

Neil Pedersen served in the fire and rescue service for 30 years before his retirement in 2019.

During his tenure he became passionate about rescue and so set up a rescue with a colleague called International Road Rescue and Trauma Consultancy.

Since its launch, the consultancy has become one of the leading providers in the UK for delivering instruction on road traffic collision, heavy vehicle rescue and trench rescue, with around 70% of the UK fire services training under its instructors.

During spring 2022, Neil became interested in the dangers of electric vehicles and the thermal runaway problem.

Since then, he’s worked to develop the recently unveiled Electric Vehicle Containment Unit (EVCU).

Why are EV Fires a Problem?

Firefighters Controlling Car Fire
Firefighters Controlling Car Fires. Image credit: Unsplash

Electric cars are inherently safe.

The problem is that when they are involved in a fire or an accident, it’s extremely difficult for the fire service to deal with them as they are dealt with completely differently to a standard car fire.

The problem with EVs is when batteries go into thermal runaway.

When a battery goes into thermal runaway it is not just a fire – it’s a chemical reaction!

Even if you submerge it in water it will continue to burn.

The fire service are wasting time trying to put it out at the roadside.

All they can do is contain flames coming out of the battery compartment, but even when it appears to have stopped, half an hour later it can start again.

How Did the EVCU Come About?

We saw the early submersion tank solutions coming out of Germany and Belgium and realised there was an opportunity.

Basically, they’re a big container of water into which a car is dropped.

We thought there’s got to be a better solution than that!

We got together with a couple of professional colleagues, one of who is a design engineer with 50 years experience, and another with 40 years of experience in the recovery industry.

With our combined expertise, we came up with the first version of what has become the EVCU.

How Does the EVCU Work?

Electric Car Fire Container
EVCU’s offer a safe and effective way of controlling electric car fires.

The EVCU is designed to be carried on a vehicle, such as a flatbed vehicle.

The flatbed lowers down to the ground, the back of the EVCU opens down to the floor, and then using the winch cable you can winch the vehicle into the container.

Once inside the container, if the vehicle hasn’t gone into thermal runaway, we try to cool the battery compartment to such an extent that it doesn’t go into thermal runaway.

There is a false floor in the bottom area of the EVCU.

Either side of the sump pump there are sprinkler bars running left and right and providing water underneath the vehicle where the battery compartment is.

When activated, this sprays water mist to the underside of the vehicle to cool it.

If the vehicle goes into thermal runaway, its battery pack will produce flames.

The EVCU’s misting system rapidly cools any flames that are coming out of the battery compartment.

We use misting rather than water droplets because the more that you atomise water, the greater cooling effect it has because it increases the surface area.

There are removable plates at either end of the unit which are sump pumps: any water that is not used goes back down into the sump.

It’s then filtered at either end so if there is a slight incline or decline the water will reach a pump that will then pump the water, after it is filtered, to the external water tank.

The header tank then sends the water back down into the belly tanks, creating an ongoing process.

All the water is used and recycled.

There are sprinkler bars along the top so if the fire spreads inside the car and the car’s glazing fails to contain the fire, these sprinklers will spray water mist directly into the car to suppress the fire development inside the vehicle.

It’s a 360-degree cooling and fire suppression system.

There are also smoke and head detectors so if a vehicle is loaded and the sprinklers have not been turned on manually if it goes into thermal runaway whilst in transit the detectors will pick this up and the system will kick in.

We advise that you activate the bottom sprinklers automatically when a vehicle is loaded even if there’s no sign of fire as this will cool the battery compartment underneath the car to prevent it going into thermal runaway.

How Does This Improve in Submersion Unit Solutions?

In 2022 after a hurricane in Florida there was an issue where electric vehicles which had been submerged during the storm were, weeks later, experiencing thermal runaway.

Following this, manufacturers said that their cars should not be submerged.

Another problem with submersion units is they don’t carry water.

If a submersion unit arrives on the scene, it’s reliant on the fire service filling it with water.

A submersion unit needs around 20,000 litres to put out an EV fire, which is likely going to involve a water shuttle service.

Then, when the vehicle submerged not only is it too heavy to move it is also surrounded by contaminated water which needs to be disposed of properly by a water treatment works.

By comparison, the EVCU only uses 1,700 litres of water, all of which is stored in water tanks on the unit.

The last thing you want to do is to submerge and flood that vehicle, which might not go into thermal runaway, because you’ve ruined the car.

With EVCU, you’re just putting water sprays underneath the vehicle to keep it cool.

You’re not damaging the car further, it’s just like driving down the road on a rainy day with water spraying under the car.

How Long Does It Take Controlling Electric Car Fires?

It’s not neutralised until an engineer disconnects the batteries.

There are lots of documented incidents where a vehicle has been taken to a scrap yard and reignited hours, days or even weeks later.

Until it can be disconnected a recovery operator ideally needs to separate it with a 15-metre gap on all sides from any other combustible substance – which in most cases is not realistic.

A better option is making concrete bays to store the vehicles in, which saves space and means that if it reignites it won’t spread to anything combustible.

What Future Plans Are There for the EVCU?

We recently hosted a launch event for the EVCU where we invited delegates from nine UK fire services to see the EVCU.

I did a presentation on it and there was a demonstration of the electric car being winched into the back of the unit to show how it all works.

There was a lot of interest there.

It’s a completely new concept – everyone out there has the problem and they’re all looking for a solution.

We’ve provided them with a potential solution to their problem.

The plan is essentially to provide people with solutions to meet the need of this growing problem put them out into the market place.

There has been a lot of interest from America, Canada, Australia and Europe looking to be our distributor.

Its early days, we’re in our infancy, but the idea is to assist numerous agencies in dealing with electric vehicle incidents.

The key thing is that there is no other recirculating units out there. It’s a turnkey solution. For more information visit the Fire Containers website.

About the Author

Neil Pedersen, is the Chief Executive Officer at Fire Containers Ltd.

He was a fully operational member of the British Fire Service for 30 years, specialising in Training and Development and Overseas project design.

Following retirement from the UK Fire Service, he now works full time assisting multiple organisations globally to help them save lives following road traffic collisions and traumatic injuries.

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