Prevent deflagration and explosion risk by gas ignition under EV fire blankets: Fire Isolator potassium nitrate Aerosol Units
During the deployment of our Fire Isolator concept, including our EV fire blankets, we have never observed a gas ignition or explosion. After more than 15 live tests, you could call that ‘luck’ — but in reality, it’s a result of the Fire Isolator concept, which goes beyond using just a blanket. A blanket alone cannot stop thermal runaway.
Removing oxygen alone will also not stop thermal runaway — something we’ve seen firsthand. As we sometimes say within the Fire Isolator team: If a blanket alone could completely extinguish the fire, you probably didn’t even need one in the first place.
Reducing the risk of deflagration is part of our concept
From the very beginning of our journey — 4.5 years ago — we’ve been searching for a way to combat the flames underneath the blanket (yes, the flames are still there, the blanket simply contains them) and to neutralize the released gases. These gases can escape through the open structure of our blankets, but you don’t want them entering the air, especially indoors — nor do you want to risk ignition or even explosion.
That’s when we arrived at the handheld potassium nitrate aerosol units we use today. Below, we explain in 6 key points why we chose this solution and how it plays a crucial role in the Fire Isolator concept to prevent gases and vapors from becoming a danger.
Before we dive in, just a quick thing: 2 of these handheld units managed to stop the thermal runaway in 2 NMC lithium-ion batteries during a live test (video of that is available).
6 ways our aerosol units work during EV fires / thermal runaway
Our Fire Isolator Potassium nitrate (KNO₃) aerosol units are designed to enhance fire suppression effectiveness, particularly in challenging scenarios like electric vehicle (EV) fires, where lithium-ion batteries can enter thermal runaway. Here’s a technical breakdown of how these units can mitigate the risks of deflagration (a rapid but subsonic explosion) in these situations:
- Chemical Composition: Potassium nitrate is an oxidizing agent that, when aerosolized, can produce fine particles that effectively disperse in the air. This property allows for a rapid and significant increase in the available oxygen in the vicinity of the fire, which can sometimes help with suppression by enhancing the efficacy of the suppressed materials.
- Cooling Effect: The aerosolization process allows for the potassium nitrate particles to be distributed over a wide area, coming into contact with the flames and hot gases emanating from the burning materials. The aerosol acts to cool the combustion zone by absorbing heat, which helps lower the temperature of the flames and surrounding gases. In cases where battery materials are combusting and generating hot gases, cooling can prevent those gases from reaching deflagration temperatures.
- Displacement of Flammable Gases: The aerosol cloud created by potassium nitrate can effectively displace flammable gases around the combustion area, reducing the concentration of combustible gases in the environment. By inhibiting the buildup of flammable vapors and gases, the risk of deflagration is reduced, thus making it safer to handle fires involving lithium-ion batteries.
- Inhibition of Reactions: Potassium nitrate can also disrupt combustion reaction pathways. When the fine aerosol particles interact with the hot combustion products, they may help in quenching radical species that are integral to sustaining combustion. This interference can further decelerate or inhibit the reactions that would typically lead to explosive deflagration.
- Thermal Stability and Interaction with Battery Chemicals: In battery fires, especially during thermal runaway, the decomposition of battery components can release highly flammable gases. The introduction of potassium nitrate can potentially alter the decomposition chemistry of these materials, delaying or preventing rapid thermal reactions that would contribute to deflagration events.
- Application together with Fire Blankets: As the blanket suppresses the immediate flames and serves as a thermal barrier, the aerosol is placed under the blanket, as close to the battery as possible (safety first) and can penetrate underneath, providing an additional cooling and displacing effect to prevent the ignition of any flammable gases trapped underneath.
In summary, potassium nitrate aerosol units facilitate a multifaceted approach to fire suppression of EV car fires with the battery in thermal runaway. By cooling the environment, displacing flammable gases, and inhibiting combustion reactions, they significantly reduce the likelihood of deflagration during a car fire, particularly when dealing with electric vehicle batteries in thermal runaway scenarios. However, it’s crucial to note that while potassium nitrate can be beneficial, comprehensive safety measures and protocols need to be in place when dealing with electric vehicle fires, as they can still present significant risks.
Can we guarantee success and full extinguishment of the fire, including stopping the Thermal Runaway?
After 15+ live tests, it is clear that the combination of our blanket, the potassum nitrate aerosol units, water mist, and eventual penetration of the battery with our EV fire gun, can bring a lot more control than just the water hose can.
First responders deploying our concept need to wear PPE and SCBA when performing all these actions and need to be trained to deploy it.
Want to know more? Please feel free to contact us!