International audienceSafety issues pertaining to Li-ion batteries justify intensive testing all along their value chain. However, progress in scientific knowledge regarding lithium based battery failure modes, as well as remarkable technologic breakthroughs in computing science, now allow for development and use of prediction tools to assist designers in developing safer batteries. Subsequently, this paper offers a review of significant modeling works performed in the area with a focus on the characterization of the thermal runaway hazard and their relating triggering events. Progress made in models aiming at integrating battery ageing effect and related physics is also discussed, as well as the strong interaction with modeling-focused use of testing, and the main achievements obtained towards marketing safer systems. Current limitations and new challenges or opportunities that are expected to shape future modeling activity are also put in perspective. According to market trends, it is anticipated that safety may still act as a restraint in the search for acceptable compromise with overall performance and cost of lithium-ion based and post lithium-ion rechargeable batteries of the future. In that context, high-throughput prediction tools capable of screening adequate new components properties allowing access to both functional and safety related aspects are highly desirable

International audienceThe use of the high energy Li-ion battery technology for emerging markets like electromobility requires precise appraisal of their safety levels in abuse conditions. Combustion tests were performed on commercial pouch cells by means of the Fire Propagation Apparatus also called Tewarson calorimeter in the EU, so far used to study flammability parameters of polymers and chemicals. Well-controlled conditions for cell combustion are created in such an apparatus with the opportunity to analyse standard decomposition/combustion gases and therefore to quantify thermal and toxic threat parameters governing the fire risk namely the rate of heat release and the effective heat of combustion as well as the toxic product releases. Using the method of O2 consumption, total combustion heats and its kinetic of production were determined as a function of the cell state of charge unveiling an explosion risk in the case of a charged cell. The resulting combustion heat is revealed to be consistent with cumulated contribution values pertaining to each organic part of the cell (polymers and electrolytes) as calculated from thermodynamic data. The first order evaluation of the dangerousness of toxic gases resulting from fire induced combustion such as HF, CO, NO, SO2 and HCl was undertaken and stressed the fact that HF is the most critical gas originating from F-containing cell components in our test conditions

Biobased production of furfural has been known for decades. Nevertheless, bioeconomy and circular economy concepts is much more recent and has motivated a regain of interest of dedicated research to improve production modes and expand potential uses. Accordingly, this review paper aims essentially at outlining recent breakthroughs obtained in the field of furfural production from sugars and polysaccharides feedstocks. The review discusses advances obtained in major production pathways recently explored splitting in the following categories: (i) non-catalytic routes like use of critical solvents or hot water pretreatment, (ii) use of various homogeneous catalysts like mineral or organic acids, metal salts or ionic liquids, (iii) feedstock dehydration making use of various solid acid catalysts; (iv) feedstock dehydration making use of supported catalysts, (v) other heterogeneous catalytic routes. The paper also briefly overviews current understanding of furfural chemical synthesis and its underpinning mechanism as well as safety issues pertaining to the substance. Eventually, some remaining research topics are put in perspective for further optimization of biobased furfural production.

International audienceTo better rule out the complex fire risk related to large format lithium ion cells, a detailed and systematic evaluation, both at component and cell levels, could be an invaluable milestone. Therefore, combustion analysis was conducted for major single organic solvents and their mixtures used in lithium ion battery technology, both in oxygen rich and lean environments using a Tewarson calorimeter. Well controlled test conditions have enabled the determination of key parameters governing the fire induced hazards such as flash point, ease of ignition, heat release rate, effective heat of combustion, specific mass loss rate, as well as the assessment of fire induced toxicity. Moreover, a rule of thumb for the screening of new solvents including the safety perspective such as the Boie correlation and N-factor were introduced for predicting the heat of combustion and combustion kinetics, respectively, prior to conducting any experimental work. Fire induced toxicity of single solvents and their mixtures was also briefly examined by performing toxic gas measurements

Li-ion secondary rechargeable batteries are becoming the preferred solution to store energy on board of new generation electric and hybrid vehicles or manage renewable energy in stationary applications. However, Li-ion batteries (LIBs) are still suffering limited lifetime, high cost and significant safety issues increasing their time to mass market. Thermal runaway is still nowadays considered as a major hazard of LIBs. This multiscale and multistep phenomenon originating at the microscale level potentially leads to uncontrolled fire and explosion of the battery. This work is focused on the development and validation of a 3D physical model of the LIB electro-thermal behavior nearby thermal runaway conditions. A combined modeling and experimental investigation provides a better understanding of the mechanisms leading to thermal runaway of LIBs, and of the ageing influence on this process. One major outcome of this work is also the proven fact that calendar ageing leads to a delayed onset of the cell self-heating temperature with a thermal runaway starting at a lower temperature. This is supported by computer simulations showing that the thickening of the solid electrolyte interface (SEI) hinders the diffusion of Li ions, which delays the degradation of the negative electrode and the occurrence of thermal runaway. HIGHLIGHTS  Development of an original 3D thermal runaway model including calendar ageing.  Model includes 3D thermal, 3D chemical reaction, and 0D calendar ageing sub-models. Calibration of the model for cylindrical 26650 LFP/C cells using a BTC. Validation of the model for fresh as well as 10% and 30% aged cells in oven tests.  Fresh and aged cells are compared in terms of critical temperatures under overheating 2