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.   

Accurate measurement of the heat release from a battery fire is vital for risk management, product development and construction of accurate models. Oxygen consumption calorimetry is the most common method for heat release measurements in experimental fire tests. The strength of the method is that it can be applied to unknown compositions of fuel with sufficient accuracy. Despite that this method is used to estimate heat release from battery fires, the method is subject to discussion. In this work, the method is studied in-depth, and potential errors are structured and quantified. Uncertainties associated with self-generated oxygen and internal heat generation, total gas release from the battery and impact on the heat release calculations, as well as the assumed E-factor (i.e., heat release per unit mass of oxygen consumed), are thoroughly discussed. For a Li-ion battery fire, it is concluded that oxygen consumption calorimetry will exclude internal heat generation and underestimate the total heat released from the external flaming fire by up to 10 %. In addition, high rate of combustion reactions can result in that the measured peak heat release rate is underestimated much more, up to 100 %. 

In the IEA Global EV Outlook 2022, Norway, Iceland, and Sweden were reported to have the highest electric car shares of the new car market: 86%, 72% and 43%, respectively. Electrification of the transport sector has multiple benefits but has also raised some concerns. Fires in electric vehicles are reported almost daily in the media and social media channels. However, fires starting in an electric vehicle traction battery (i.e., lithium-ion battery) are rare. If the traction battery catches fire, it can be difficult to extinguish since the battery pack in an electric vehicle is generally well protected and difficult to reach. To cool the battery cells, firefighters must prolong the application duration of suppression agent. This results in the use of large amounts of water, that potentially could carry pollutants into the environment. In this work, the analysis of extinguishing water from passenger vehicle fires are reported. Three large-scale vehicle fire tests were performed, the vehicles used were both conventional petrol fuelled and battery electric. Tests were performed indoors at RISE, Borås and the test setup allowed analysis of both combustion gases and extinguishing water. Results show that all analysed extinguishing water was highly contaminated. Additionally, the ecotoxicity analysis of the extinguishing water showed that the extinguishing water was highly toxic towards the tested aquatic species, independent of the traction energy of the vehicle.

Fires involving electric vehicles have attracted considerable attention in the media. In particular, the toxic gases released upon combustion of electric vehicles and lithium-ion batteries has been a major concern. In this study, the results of six large-scale vehicle fire tests are presented including three electric vehicles, two internal combustion engine vehicles, and one electric vehicle with the battery pack removed. Additionally, separate battery component tests were performed. In two of the vehicle fire tests a sprinkler system was used to assess the effect of water application on the combustion gases. Furthermore, calculations of the heat release rate, peak heat release rate and total heat release were performed, as well as chemical analysis of gas and soot. Peak heat release rate and total heat release were affected by the fire scenario and vehicle model, but not significantly by the type of powertrain. Regarding the combustion gases, hydrogen fluoride represented the largest difference between electric vehicles and internal combustion engine vehicles. Additionally, battery specific metals such as manganese, nickel, cobalt and lithium were found in higher concentrations in the electric vehicle tests than in the internal combustion vehicle tests, in which larger quantities of lead were found.

The project "Battery Fire Safety Ventilation for Fully Electrical Vessel" is a follow-up project to the previous project "Electric Light", both carried out within the Swedish Transport Administration’s industry program Sustainable Shipping. The objective of the project is to develop ventilation concepts and post-fire strategies for fully electric Ro-Pax ships (roll-on/roll-off passenger ships) for international voyages. The project aims to develop design guidelines for ventilation system concepts, considering the management of thermal runaway scenarios. It also seeks to initiate a strategy for changing ventilation rates based on different fire suppression and ventilation concepts. Additionally, the project aims to develop strategy for purging battery rooms that may contain flammable gases and for removing damaged batteries from the battery room in the ship's bottom deck. The project acknowledges that regulations regarding battery installations and safety on board vessels are still developing. Classification societies such as DNV, Bureau Veritas, and Lloyd's Register are working on rules and recommendations, but they are currently vastly subjective and qualitative in nature. This project aims to improve quantitative definitions, requirements, and procedures to further enhance existing and future regulations. The project methodology involves close cooperation with industry partners, regulatory bodies, and experts in battery safety, electrical engineering, fire safety, and ship design. Workshops, focus discussions, and regular meetings have been conducted to gather input, discuss ventilation design concepts, and address regulatory aspects. The project has also considered different battery chemistries and their safety aspects. The project outcomes revealed deficiencies in battery room ventilation design, regulation, and operation. The general concept emphasized the importance of off-gas ducts and propagation safety within battery modules for optimal ventilation design. Overall, the project aimed to address these issues and provide ventilation solutions for different scenarios to ensure safety in a fully electric Ro-Pax ship.

Electrified transport has multiple benefits but has also raised some concerns, for example, the flammable formulations used in lithium-ion batteries. Fires in traction batteries can be difficult to extinguish because the battery cells are well protected and hard to reach. To control the fire, firefighters must prolong the application of extinguishing media. In this work, extinguishing water from three vehicles and one battery pack fire test were analyzed for inorganic and organic pollutants, including particle-bound polycyclic aromatic hydrocarbons and soot content. Additionally, the acute toxicity of the collected extinguishing water on three aquatic species was determined. The vehicles used in the fire tests were both conventional petrol-fueled and battery electric. For all of the tests, the analysis of the extinguishing water showed high toxicity toward the tested aquatic species. Several metals and ions were found in concentrations above the corresponding surface water guideline values. Per- and polyfluoroalkyl substances were detected in concentrations ranging between 200 and 1400 ng L^–1. Flushing the battery increased the concentration of per- and polyfluoroalkyl substances to 4700 ng L^–1. Extinguishing water from the battery electric vehicle and the battery pack contained a higher concentration of nickel, cobalt, lithium, manganese, and fluoride compared with the water samples analyzed from the conventional vehicle.

This study was performed by RISE Research Institutes of Sweden on behalf of Volvo Trucks. RISE Research Institutes of Sweden was requested to conduct a study regarding the differences between fires in conventional internal combustion engine (ICE) trucks and electric trucks. A set of guiding questions (see section Aim) were given by Volvo Trucks and in this report these questions have been answered. The questions have been answered by performing literature searches and through previous knowledge of RISE. However, for some questions, due to scarcity of data on electric truck fires, knowledge regarding electric passenger cars has been used. In addition, contact has been made with fire and rescue services around the world (Australia, UK, USA, Sweden and Finland) to collect their views on management of fires in electric vehicles (EVs). The main conclusions are: • Data on electric truck fires are scarce due to the low number of vehicles as well as the low number of fire incidents. Available data show that battery electric passenger vehicle fires are less common than ICE vehicle fires, but that the risks are different. The main differences are that battery fires tends to be harder to extinguish than fires in ICE vehicles and that there is a risk of accumulation of flammable gases, especially in enclosed spaces, upon thermal runaway. • Lithium iron phosphate (LFP) type cells, in comparison with nickel-based type cells (such as lithium nickel manganese cobalt oxide (NMC) and lithium nickel cobalt aluminium oxide (NCA)), have a higher thermal runaway onset temperature, a slower temperature increase rate, a lower maximum temperature as well as a lower gas production in total amount. However, the specific total gas production (L Ah-1) can sometimes be higher for LFP-type cells and depends on the state of charge and on the amount of electrolyte in the cell. However, the safety of a battery pack in a vehicle is determined by several factors such as preventive measures aimed at reducing the occurrence of fires (safe design). For example, by early detection and pro-active mitigation using the battery management system and thermal management system and by limiting the thermal propagation in the battery pack, reducing the extent of damage. • Fires in enclosed spaces, such as in underground parking garages and tunnels, generally imply a higher risk for firefighters due to the trapped smoke, decreased visibility and longer access routes than in open structures. Risk reduction measures for battery fires should focus on early detection of harmful events, reducing thermal propagation in the battery pack and on limiting the extent of fire spread. The severity of the consequences of vehicle fires (no matter if is an EV or an ICEV) in enclosed spaces could be reduced using suppression systems, such as a water sprinkler system, to hinder fire spread between vehicles.

Energy storage is essential for enhancing the stability, efficiency and sustainability of the modern energy supply chain. It can help reduce the dependency on fossil fuels and increase the use and market penetration of renewable energy sources such as wind and solar power, which are intermittent and variable. The most common technology for short storage times (minutes to days) is electrochemical energy storage, and more specifically lithium-ion battery energy storage systems (BESS). In line with the EU ambition for more sustainable electric vehicle batteries, it is likely that second life applications and repurposing of electric vehicle batteries will increase. One of the main challenges for the deployment of BESS is the fire safety of lithium-ion batteries. Today, there is a lack of national guidelines in Sweden for how to design a BESS in terms of fire safety, which causes uncertainty. Without national guidelines, each municipality and local fire and rescue service must develop their own advice, which may result in inconsistent and costly solutions with a varying degree of fire protection. The aim of this study was to produce national guidelines for the fire protection of BESS. The guidelines were produced by literature searches, review of relevant laws, regulations and standards, review of international guidelines, workshops, information retrieval from project partners and through studying lessons learnt from previous incidents. The produced guidelines (found in Appendix C, in Swedish) are formed around three application categories, based on the type of application and user, which reflect the size of the BESS. For the first category, BESS for single-family home use, guidance is given for separated placement of BESS, remote fire alarm, and separated ventilation. For the second category, BESS for multi-dwelling blocks or businesses, recommendations regarding placement, detection and ventilation are increased. It is also advised to have an installation that allows the fire and rescue services to ventilate fire gases without opening doors and that emergency response plans are produced. For the third category, BESS for large-scale commercial applications and mobile BESS, some further requirements are introduced. They include risk analysis, separate building and fire cell demands, as well as recommendations for CCTV and gas monitoring as well as fire hose connection. The guidelines assume that current national laws and building regulations are complied with. Additionally, insurance companies may have their own guidance which should be checked before installation. The guidelines produced in this project should thus be used as a supporting tool or when an increased level of protection is sought. The guidelines only address BESS with lithium-ion batteries. It was not included in the work to evaluate whether special requirements should apply for reused or remanufactured batteries (second-life).

The increasing use of lithium-ion batteries requires further efforts in safety testing and evaluation. It is of utmost importance that the effects of different test conditions are understood, particularly for validation of computer models. While plenty of data from thermal runaway tests are available in literature, few are from large test series. The missing systematic approach to evaluate the impact of different test conditions implies uncertainty when comparing test results. In addition, the fast pace in cell development, including an increasing utilization of larger cells, necessitate the validation of previously published results. This work presents thermal runaway data from 37 tests on one type of large format prismatic lithium-ion cell (157 Ah). The tests are conducted in a closed pressure vessel with inert atmosphere as well as in an open setup below an exhaust collector hood. Further, six different thermal runaway trigger methods are employed as well as four different states of charge. Emphasis is put on the gases produced, a key aspect for safety evaluation. The results are compared with literature data and a new modified method is proposed for calculating the characteristic venting rate in a closed pressure vessel. It is concluded that the trigger method affects the gas production rate, mass loss, and maximum temperature of the cell as much as its state of charge. The large cell format potentially impacts the specific total gas production and enhances the effects of different trigger methods, but has a small impact on other evaluation parameters. No significant differences were observed in the test results due to the different test setups, apart from differences due to potential combustion of the released gases in ambient atmosphere.