Use an F500 fire extinguisher or a similar lithium-ion capable extinguisher. Once a thermal runaway begins, the best option is to submerge the battery in water and contain it.
How do you extinguish a high-voltage battery fire?
For fire extinguishment, responders should wear full PPE and use water or other standard agents. It is important to use a large volume of water to extinguish high-voltage battery fires and monitor the battery for reignition using thermal imaging while ensuring a safe storage distance from structures or other vehicles.
With the arrival of electric vehicles (EVs) comes many different products to “solve” the problem of extinguishing a fire in an EV's high-voltage battery. While there may be a few benefits to some of these products, overall, most fail to address the problem associated with a thermal runaway event in a large lithium-ion battery.
Are lithium ion battery cells a fire extinguisher?
While they are called lithium-ion battery cells, the cells do not contain solid lithium metal, making the extinguisher ineffective. There is also no easy way to get the powder from the extinguisher directly to the cells on fire due to the construction of the box and the speed at which the battery cells fail.
The group's report, “ Best Practices for Emergency Response to Incidents Involving Electric Vehicle Battery Hazards: A Report on Full-Scale Testing Results,” which is available at nfpa.org, includes many lessons learned, such as the need for copious amounts of water to extinguish a burning li-ion battery fire.
Firefighting foam, Class D extinguishers, pancake nozzles, fire blankets, and piercing nozzles all have their limitations and may not be effective in stopping a thermal runaway event due to the design of the battery box, the speed at which battery cells fail, and the fact that lithium-ion batteries do not require external oxygen to burn.
To address this challenge, one fire department's tactic is to lift or tilt the EV enough so that cooling water can be concentrated on one area of the battery then moved to another area as the battery and the errant cells that are inside of it cool down. Battery box piercing.