HANDLING FIRES INVOLVING EV TRACTION BATTERIES

In collaboration with several other companies and organisations, Cold Cut Systems has investigated whether Cobra can be used to stop thermal propagation in lithium-ion traction battery packs in electric vehicles.

After years of systematic testing and knowledge acquisition, Cold Cut Systems is delighted to finally be able to pass on our knowledge and experience to others. The test results have been very positive, showing that stopping thermal propagation in tested electric vehicle (EV) lithium-ion traction battery packs is possible.

Fully developed propagations in EV lithium-ion battery packs are very rare. But when they occur, Fire and Rescue Services lack a practical method to interrupt thermal propagation within the battery pack. Until today, the methods available mainly comprise different ways of limiting fire spread and/or cooling the propagating battery pack externally with large amounts of water. In addition, there is a risk of re-ignition when handling affected lithium-ion batteries.

Based on the findings, we can present a manageable solution to one of the Fire and Rescue Services biggest challenges. The test results show that there is a method for stopping propagation in tested EV lithium-ion traction battery packs.

Tested & Proven

We received early indications that Cobra could be a suitable tool for this type of fire. However, one of the cornerstones of Cold Cut Systems’ philosophy is that what we say about Cobra and its effects must be properly tested and evaluated. We, therefore, started a pre-study in 2021 to investigate Cobra’s effect when used on fires in EVs with lithium-ion battery pack.

The findings from the pre-study showed promising results for further studies and tests. In 2022 we therefore, joined a collaborative project. This new project was a joint effort between automotive industry stakeholders and equipment manufacturers, with the Swedish Civil Contingencies Agency (MSB) as project leader.

Several controlled tests on propagating lithium-ion battery packs have been made within the project. In the initial tests, different tools, including Cobra, were used to demonstrate the efficiency of stopping propagation by establishing an internal water flow as close as possible to the affected and surrounding battery modules, thus cooling the module and stopping propagation. In the final full vehicle test, only Cobra was used.

Overall, the project showed that it is possible to stop propagation in a battery pack by means of internal cooling with water. The ultra-high pressure water mist and capability to pierce through any known construction material makes Cobra a very well-suited tool for this purpose.

Importantly, Cobra has demonstrated the ability to stop propagation in tested EV traction battery packs while remaining a versatile firefighting tool that can be used in a wide range of firefighting scenarios.

Norwegian firefighters successfully put out burning EV

About the Project

The objective was to study the potential of improving interventions and reduce the amount of extinguishing water necessary to stabilise thermally-damaged lithium-ion traction battery packs. In addition, the demonstrated method was intended to enable safer handling after incidents involving electric vehicles with lithium-ion traction battery packs.

The overall aim of the demonstration was to contribute with experimental experience to the methodology of flooding lithium-ion battery packs with water in the event of fire where the traction battery is involved and to show that it can contribute to faster and more efficient extinguishing, provided that it is possible to access the battery pack in a safe way. The method aimed to stop thermal propagation in the lithium-ion traction battery pack.

Successful Results

The results of the project are considered to be successful; the propagation was stopped and thermal runaway was interrupted. All tests within the project have been completed, and a report with the findings and results is now published. The conclusion is that the project demonstrated that propagation in tested EV lithium-ion traction battery packs can be stopped through internal cooling with water. In addition to demonstrating the response methodology, the project also addresses the causes of propagation and handling of incidents involving EV lithium-ion traction battery packs.

How do you manage an EV fire involving the traction battery?

Research, testing and documented operational experience indicate an effective method for using Cobra to manage electric vehicle fires where the lithium-ion traction battery pack is involved. Cobra interrupts an ongoing propagation by internally flooding the battery with water, which cools it and prevents further propagation in unaffected battery modules. Cobra’s ultra high pressure cutting capability enables rapid access to the battery enclosure and helps establish an internal water flow that cools the battery modules. Here is a concise summary of the method:

To efficiently manage an electric vehicle fire involving the traction battery, begin with a thorough risk assessment to ensure the situation is safe, and ensure you are wearing appropriate protective gear. Extinguish the car fire according to your organisation’s standard procedure. Use a Thermal Imaging Camera (TIC) to locate hot spots. Position the Cobra lance as close to the hot spot as possible and cut through the vehicle’s structure to access the traction battery pack. Establish an internal water flow and flood the battery pack to cool it and stop the propagation. Continue flooding until the battery pack’s temperature has dropped and reached a stable level.

We recommend that you take our Cobra & EV battery fire course to become fully prepared to deal with EV fires.

How Do You Put Out a Lithium-Ion Battery Fire?

“Demonstration of an extinguishing method for lithium-ion batteries”*

The report can be found on the Swedish Civil Contingencies Agency (MSB) website, www.msb.se (currently in Swedish only)

*Freely translated from the original title: “Demonstration av släckmetodför litiumjonbatterier. Metodtillämpning på olika aggregationsnivåer – modul, sub-batteri, elbilspack och fordonsnivå”

Please note

In the event of an electric vehicle accident, it is important that the vehicle’s rescue data sheet is used and that other safety routines are followed. The temperature of the battery pack should be monitored continuously with a thermal imaging camera.

Full EV test images

The images on the full car fire tests on this page visualizes the tests on the full Electric Vehicle and is not from the actual test as those images cannot be published due to legal reasons.