There has been a steady rise in Lithium-ion battery fires in recent years, as the number of devices containing these kinds of batteries increases. Lithium-ion battery fires have unique characteristics and are different from other types of fire. Understanding how to tackle these fires is critical if the worst were to happen.
Here at Firechief®, we provide a range of lithium-ion battery fire extinguishers, specifically designed to tackle this risk using a vermiculite-based solution. We often get asked about the role that fire extinguishers play in managing and mitigating Lithium-ion battery fires, and especially what makes our Lith-Ex fire extinguishers the best solution for lithium-ion battery fires.
What is vermiculite & aqueous vermiculite dispersion (AVD)?
Vermiculite is a naturally occurring mineral that becomes a very thin platelet structure (about 180 microns) when it is broken down. Vermiculite is environmentally friendly as it is a completely natural product and is REACH-compliant.
In Lith-Ex extinguishers, vermiculite is used as a suspension, known as Aqueous Vermiculite Dispersion (AVD). AVD has a consistency similar to double cream when you hold it in your hands (the viscosity is 3000 cPs). Because AVD is a suspension, it doesn’t come as a concentrate that needs to be handled in any way. It remains in its suspended form within the extinguisher for the full lifetime of the product.
How does AVD tackle a lithium-ion battery fire?
To understand how AVD tackles a lithium-ion battery, it’s important to understand what’s inside a Lith-Ex fire extinguisher. The basic makeup of the extinguishant is 83% water, and 17% is AVD.
When a Lith-Ex extinguisher is deployed, the water provides quick cooling while the vermiculite suppresses and isolates the fuel source. The vermiculite then acts as a fire-blocking barrier between the cell(s) already in a state of thermal runaway, and other cells with the battery unit. This prevents further propagation of the fire. It also provides a barrier over the top of the battery, cutting off any additional oxygen source and limiting the emission of toxic fumes. Although lithium-ion battery fires are self-oxygenating, limiting access to additional oxygen helps to control and suppress the fire. The vermiculite will then start to dry and form a crust encapsulating the battery and the device the battery is associated with.
Why is AVD more effective than other extinguishants?
It’s important to understand that conventional extinguishing agents vary in their ability to deal with a lithium-ion battery fire. Their different properties mean that while some might have a level of suppression, they’re not going to be able to make the fire safe. The only way to do this is by reducing, slowing and stopping thermal runaway.
Lith-Ex
Firechief® Lith-Ex extinguishers are 83% water-based because water is the most effective method of cooling a fire. The remaining 17% is AVD which encapsulates to cut the cell off, thereby cutting the reaction down. You need to cool, create a firebreak, and stop the reaction, so the quicker you can do that, the quicker you can make the battery safe. This is where the water and vermiculite combined make Lith-Ex extinguishers the most effective fire extinguisher solution available for Lithium-ion battery fires.
Water
Simply using a water extinguisher on a Lithium-ion battery fire will cool it but it won’t encapsulate it to form a thermal barrier around the cell. This thermal barrier is a key requirement to prevent thermal runaway from propagating to the other cells in the battery. Once the water extinguisher is empty, the thermal runaway reaction will start all over again. So although, in effect, water will cool a lithium-ion battery, huge volumes of water will be required to keep the battery cool. Additionally, you will still need a barrier between the cells to stop the propagation.
Foam
Foam extinguishers are even less effective than water-based agents. The foam doesn’t perform to meet the high-temperature characteristics of a lithium-ion battery fire, so it simply isn’t effective.
Powder
Powder extinguishers are completely ineffective on a lithium-ion battery fire as the powder has no cooling effect and won’t encapsulate the cells either, as it does not adhere to vertical surfaces.
Is there a standard for lithium-ion battery fire extinguishers?
At the moment of writing, there is no Lithium-ion battery fire standard, but the internal EN NTA 8133 Dutch standard is becoming the most globally recognised standard and is being adopted by BSI as their test standard for Lithium-ion battery fires.
We hope this will be adopted as quickly as possible and in the meantime we are working with other standards agencies to certify and verify our products as much as possible. That’s why the Lith-Ex fire extinguishers already hold the Marine Directive, UKCA, UL Independent Test, and BSI Kitemark (for Class A fire rating). In effect, the Lith-Ex fire extinguishers hold as many relevant standards as are currently available.
Download the full set of FAQ’s to learn more about AVD and understand why it’s the most effective fire extinguisher solution for lithium-ion battery fires.
Disclaimer
The Firechief® range includes high-performance fire extinguishers, fire blankets, first aid kits, lithium-ion fire extinguishers and the Kitchen Stove Guard. For more information, call us on +44 (0)330 999 0019 or email sales@firechiefglobal.com.
The information contained within this blog is provided solely for general informational and educational purposes and is not intended as a substitute for professional advice. Before taking any actions based upon this information, we advise the reader to consult any and all relevant statutory or regulatory guidance and where felt necessary to consult a qualified fire or industry regulation professional. The use or reliance on any information contained herein is solely at the reader's risk.