The shipping industry is facing increasing pressure to cut emissions. Diesel-electric hybrid or fully electrical propulsion systems can offer significant savings in fuel consumption and reduce emissions. However, the use of energy storage battery systems on board vessels is introducing new fire hazards and advice on suitable fire extinguishing systems and agents is desired. In a series of tests, both total compartment application water spray and water mist systems and direct injection (using several different agents) into the module were evaluated in fire tests conducted to compare different fire extinguishing approaches for a fire in a battery cell. A test compartment was constructed to simulate a battery room and a commercially available lithium-ion (Li-ion) battery cell was positioned inside a cubic box that mimicked a battery module. By heating the battery cell, combustible gases were generated, and these gases were ignited by a pilot flame inside the simulated battery module. The tests indicated that fire extinguishment of a battery cell fire inside a battery module is unlikely when using total compartment water spray or water mist fire protection systems. The water droplets are simply not able to penetrate the battery module and reach to the seat of the fire. Direct injection of the fire extinguishing agent inside the battery module is necessary. The tests also showed that agents such as water and low-expansion foam, with a high heat capacity, provide rapid cooling and fire extinguishment. The reduced water surface tension associated with low-expansion foam may improve the possibilities for water penetration whilst agents with a high viscosity may not be able to spread to the seat of the fire. Agents with less heat capacity, such as high-expansion foam and nitrogen gas, provide less cooling but fire extinguishment can still be achieved if designed correctly.

Batteries, in particular lithium-ion (Li-ion) batteries, are seen as an alternative to fossil fuels in the automotive sector. Li-ion batteries, however, have some safety issues including possible emissions of toxic fluorine-containing compounds during fire and other abuse situations. This paper demonstrates the possibilities to use the Fourier transform infrared technique to assess some of the most important compounds, including hydrogen fluoride and the far less often measured POF₃ and PF₅. The study is conducted in the cone calorimeter with different solvents used in Li-ion batteries. The measurements show that, in addition to hydrogen fluoride, with a known high toxicity, POF₃ is emitted and can be quantified using Fourier transform infrared.

Electric propulsion using batteries as energy storage has the potential to significantly reduce emissions from shipping and thus the environmental impact. The battery type that is currently on the top of the agenda to be used for ship propulsion applications is Li-ion batteries. Li-ion batteries pose different safety issues than e.g. other propulsion technologies and other batteries such as lead-acid batteries. It is essential that the safety level on board, including fire safety, is maintained, when introducing electric propulsion with energy storage in batteries. This report discusses the different regulations and guidelines available today for fire safety of batteries on board in relation to current knowledge about Li-ion batteries. Also fire safety measures available on board ships today and their applicability for Li-ion batteries is discussed, as well as the different test methods available and their applicability. A workshop gathering different stakeholders from Sweden, Norway and Finland identified fire safety as the main challenge for the introduction of battery propulsion at sea. The workshop concluded that future work is desired in order to increase knowledge and to develop publicly available strategies, training and designs.

In the last few years the use of Li-ion batteries has increased rapidly, powering small as well as large applications, from electronic devices to power storage facilities. The Li-ion battery has, however, several safety issues regarding occasional overheating and subsequent thermal runaway. During such episodes, gas emissions from the electrolyte are of special concern because of their toxicity, flammability and the risk for gas explosion. In this work, the emissions from heated typical electrolyte components as well as from commonly used electrolytes are characterized using FT-IR spectroscopy and FT-IR coupled with thermogravimetric (TG) analysis, when heating up to 650 °C. The study includes the solvents EC, PC, DEC, DMC and EA in various single, binary and ternary mixtures with and without the LiPF6 salt, a commercially available electrolyte, (LP71), containing EC, DEC, DMC and LiPF6 as well as extracted electrolyte from a commercial 6.8 Ah Li-ion cell. Upon thermal heating, emissions of organic compounds and of the toxic decomposition products hydrogen fluoride (HF) and phosphoryl fluoride (POF3) were detected. The electrolyte and its components have also been extensively analyzed by means of infrared spectroscopy for identification purposes.

Lithium-ion (Li-ion) batteries offer great energy and power densities accompanied with long battery life time. However, if a mechanical fault occurs or the batteries over-heat, the flammable electrolyte of the Li-ion battery may pose a  risk. For Eurotransport, colleagues  from  the SP Technical Research Institute of Sweden (SP) and Chalmers University of Technology explore further, identifying the risks involved with electric buses.

A model is presented for predicting the cell-to-cell propagation of a thermal runaway/fire in a lithium-ion battery cell to neighboring cells by simulating the temperature development in neighboring cells. The modelling work comprises of two major steps; setting up a model of the cells including the thermal properties of the cells, and then validating the model through experiments where the boundary conditions in the validation test must be determined carefully. The model is developed to allow a fast evaluation of several different preventive means of thermal insulation, it is not modelling the pack and cells to a great detail. Still the experimental validation indicates that the model is good enough to fulfil its purpose of the model. A feasibility study using the model is conducted assessing two different types of fire walls between battery modules of 10 cells. The results show that there is a substantial risk for a cascading of thermal events in a battery pack, although cooling systems and fire walls may mitigate these risks

Commercial lithium-ion battery cells are exposed to a controlled propane fire in order to evaluate heat release rate (HRR), emission of toxic gases as well as cell temperature and voltage under this type of abuse. The study includes six abuse tests on cells having lithium-iron phosphate (LFP) cathodes and, as a comparison, one test on conventional laptop battery packs with cobalt based cathode. The influence of different state of charge (SOC) is investigated and a limited study of the effect of water mist application is also performed. The total heat release (THR) per battery energy capacity are determined to be 28-75 kJ Wh-1 and the maximum HRR values to 110-490 W Wh -1. Hydrogen fluoride (HF) is found in the released gases for all tests but no traceable amounts of phosphorous oxyfluoride (POF3) or phosphorus pentafluoride (PF5) are detected. An extrapolation of expected HF emissions for a typical automotive 10 kWh battery pack exposed to fire gives a release of 400-1200 g HF. If released in a confined environment such emissions of HF may results in unacceptable exposure levels.

Lithium-ion battery fires generate intense heat and considerable amounts of gas and smoke. Although the emission of toxic gases can be a larger threat than the heat, the knowledge of such emissions is limited. This paper presents quantitative measurements of heat release and fluoride gas emissions during battery fires for seven different types of commercial lithium-ion batteries. The results have been validated using two independent measurement techniques and show that large amounts of hydrogen fluoride (HF) may be generated, ranging between 20 and 200 mg/Wh of nominal battery energy capacity. In addition, 15-22 mg/Wh of another potentially toxic gas, phosphoryl fluoride (POF3), was measured in some of the fire tests. Gas emissions when using water mist as extinguishing agent were also investigated. Fluoride gas emission can pose a serious toxic threat and the results are crucial findings for risk assessment and management, especially for large Li-ion battery packs.

Safety issues concerning the use of large lithium-ion (Li-ion) batteries in electrified vehicles are discussed based on the abuse test results of Li-ion cells together with safety devices for cells. The presented abuse tests are: overcharge, short circuit, propane fire test and external heating test (oven). It was found that in a fire, cells with higher state of charge (SOC) gave a higher heat release rate (HRR), while the total heat release (THR) had a lower correlation with SOC. One fire test resulted in a hazardous projectile from a cylindrical cell. In the fire tests, toxic gas emissions of hydrogen fluoride (HF) were measured for 100%, 50% and 0% SOC.

Commercial 6.8 Ah lithium-ion cells with different ageing/status have been abused by external heating in an oven. Prior to the abuse test, selected cells were aged either by C/2 cycling up to 300 cycles or stored at 60 °C. Gas emissions were measured by FTIR and three separate vents were identified, two well before the thermal runaway while the third occurred simultaneously with the thermal runaway releasing heavy smoke and gas. Emissions of toxic carbon monoxide (CO), hydrogen fluoride (HF) and phosphorous oxyfluoride (POF3) were detected in the third vent, regardless if there was a fire or not. All abused cells went into thermal runaway and emitted smoke and gas, the working cells also released flames as well as sparks. The dead cells were however less reactive but still underwent thermal runaway. For about half of the working cells, for all levels of cycle ageing, ignition of the accumulated battery released gases occurred about 15 s after the thermal runaway resulting in a gas explosion. The thermal runaway temperature, about 190 °C, varied somewhat for the different cell ageing/status where a weak local minimum was found for cells cycled between 100 and 200 times.

Lithium-ion batteries offer great energy and power densities but the thermal stability is an issue of concern compared to other battery technologies. In this study different types of abuse testing have been performed in order to compare the battery safety for different types of commercial lithium-ion battery cells. The results show large differences in abuse response for different cells. Exposed to external heating laptop cells with cobalt based cathode developed a thermal runaway resulting in pressure release, fire and temperatures over 700°C. Lithium iron phosphate (LFP) is known to be a very thermally stable cathode material and LFP-cells showed a significantly lower thermal response, a thermal runaway could, however, be detected for some of the cells in the external heating test. The overcharge tests of LFP-cells were in most cases uneventful but in one case the test resulted in a violent fire. The short circuit tests showed modest temperature increases of the cells in spite of high currents peaking at around 1000 A. Although the development of safer lithium-ion battery cells has been successful thermal runaway events may still occur under extreme conditions.

This report presents a general and broad risk assessment and construction guidelines for lithium-ion battery systems used in electrified vehicles, from the perspectives of fire and gas release. General types of Li-ion battery systems and electrified vehicles, ranging from light to heavy-duty vehicles, are included. The findings in the report are based on results obtained in the project “Safer battery systems in electrified vehicles – develop knowledge, design and requirements to secure a broad introduction of electrified vehicles”, conducted between the years 2012-2017 and lead by RISE Research Institutes of Sweden. The guidelines focus on both how to design the battery system and on how to integrate and place the battery in the vehicle in order to increase the safety in terms or fire and gas release.

Overcurrent abuse has been performed on commercial 48 Ah primary prismatic zinc (Zn)–Air battery cells with full air supply as well as with shut-off air supply. Compared to other battery technologies, e.g., lithium-ion batteries, metal–air batteries offer the possibility to physically stop the battery operation by stopping its air supply, thus offering an additional protection against severe battery damage in the case of, e.g., an accidental short circuit. This method may also reduce the electrical hazard in a larger battery system since, by stopping the air supply, the voltage can be brought to zero while maintaining the energy capacity of the battery. Measurements of Overdischarge currents and current cut-off by suffocation have been performed to assess the safety of this type of Zn–air battery. The time to get to zero battery voltage is shown to mainly be determined by the volume of air trapped in the cell.

System level simulators allow computer architects and system software designers to recreate an accurate and complete replica of the program behavior of a target system, regardless of the availability, existence, or instrumentation support of such a system. Applications include evaluation of architectural design alternatives as well as software engineering tasks such as traditional debugging and performance tuning. We present an implementation of a simulator acting as a virtual workstation fully compatible with the sun4m architecture from Sun Microsystems. Built using the system-level SPARC V8 simulator SimICS, SimICS/sun4m models one or more SPARC V8 processors, supports user-developed modules for data cache and instruction cache simulation and execution profiling of all code, and provides a symbolic and performance debugging environment for operating systems. SimICS/sun4m can boot unmodified operating systems, including Linux 2.0.30 and Solaris 2.6, directly from snapshots of disk partitions. To support essentially arbitrary code, we implemented binary-compatible simulators for several devices, including SCSI, console, interrupt, timers, EEPROM, and Ethernet. The Ethernet simulation hooks into the host and allows the virtual workstation to appear on the local network with full services available (NFS, NIS, rsh, etc). Ethernet and console traffic can be recorded for future playback. The performance of SimICS/sun4m is sufficient to run realistic workloads, such as the database benchmark TPC-D, scaling factor 1/100, or an interactive network application such as Mozilla. The slowdown in relation to native hardware is in the range of 25 to 75 (measured using SPECint95). We also demonstrate some applications, including modeling an 8-processor sun4m version (which does not exist), modeling future memory hierarchies, and debugging an operating system.