Design rules for battery fire safety in dwellings

The report presents a review of current literature, testing and modelling in support of guidelines how to address current risks with batteries from e-bikes and e-scooters. It has been shown that a fire initiated in a battery module can have an exceedingly fast fire growth and may pose new risks that cannot be accommodated within the current design methodology. The data from measurements indicated that the fire growth in terms of heat release rates may be faster than the currently used models. The tests present typical heat release rates from open fire tests in combination with release of toxic and flammable gases from cells and modules. Using accelerating rate calorimetry, conditions when single cells enter a thermal runaway could be determined. Utilizing the information from the testing, simulations of a module were performed to investigate the effect of mass ejection from cells during the thermal runaway, complementing the knowledge how the thermal propagation was disrupted in the module. The information gathered from literature, testing and modelling was used to propose a design fire. Although, the fully developed fire is no more severe than a usual fire the very fast fire growth rate may cause deflagration type events that compromises the fire resistance properties. Note that while the proposals are general, they mainly influence possible future dwellings thus dissemination of current risks to the public is necessary. Some of the recommendations can be summarized as follows; Being mindful of batteries and where to charge battery modules; Keep a watch on the health of your batteries, which includes but are not limited to observing if they have been damaged in any way or become unusually hot during operation and perhaps most importantly do not charge batteries where escape routes can be compromised.