Fire experiment to examine the use of ultra high pressure extinguishing systems for fires in batteries of electric vehicles | Nederlands Instituut Publieke Veiligheid (NIPV) 26 November 2024
Abstract
The number of electric vehicles in the Netherlands has grown rapidly in recent years and continues to increase. When the battery pack of these vehicles is involved in a fire or something goes wrong internally, the battery pack can go into a ‘thermal runaway’. Fighting a thermal runaway is complex and, in addition, current deployment techniques are not always optimal. The aim of this research is to use fire experiments to determine whether an ultra high pressure (UHP) extinguishing system can be used safely and effectively, and is suitable for practical application, by the Dutch fire service in order to fight battery fires in electric vehicles. Nine questions were formulated for this research. They were answered through a preliminary study, consisting of a working visit, a literature review, and interviews.
Additionally, two almost identical experiments were conducted, in which the battery pack of an electric car was put into thermal runaway.
It was found that it is practically feasible to deploy a UHP extinguishing system safely and effectively in the Netherlands to control or extinguish an unstable or burning battery pack in an electric vehicle, provided a number of specific safety measures are taken for this purpose.
These safety measures are:
- Deploying low-pressure jets to suppress any jet fires from the battery pack, and to shield the UHP operator to protect them from exposure to any (unexpected) jet fires.
- Determining that no flammable gases have accumulated in or around the vehicle. Busting the windows with the UHP extinguishing system, possibly supported by the use of fans, can help vent flammable gases.
- Positioning the UHP operator and other fire personnel as far away as possible from the (toxic) smoke and flames.
- Use of the long lance or extension of the UHP extinguishing system.
During the experiment, an effective deployment procedure was confirmed. This procedure consisted of identifying hot spots with a Thermal Imaging Camera, and then penetrating the battery pack and using the UHP extinguishing system to introduce water to these hot spots. Here, steam formation is an indicator that cooling is effective, and the transition from steamy to leaking water is an indicator that the deployment has been effective and can be terminated. After this, a period of visual monitoring is necessary to ensure that the situation has stabilised and there is no re-ignition. Participating fire personnel indicated that this deployment gave them a positive feeling and was relatively easy to carry out.
In conclusion, the results of the fire experiments provide sufficient confidence to have (specialised) UHP units within the Dutch fire service deploy UHP extinguishing systems in case of fires in the battery packs of electric vehicles.
Visit NIPV's website for mor information
This page provides more detailed and updated information from NIPV about their tests and reports on using ultra-high-pressure systems to extinguish electric vehicle battery fires.
