Cerfacs Enter the world of high performance ...

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Abstract :

The development of more sustainable energy supply chains is accompanied by an evolution of the demand for safe and efficient storage solutions. Among them, Lithium-ion batteries benefit from the maturity of a technology developed and applied for more than three decades. However, when misused or in case of a manufacturing defects, Lithium-ion batteries may uncontrollably trigger decomposition reactions: the so-called Thermal Runaway process. The reactions produce heat and flammable gases, leading to fires when the battery vents out these gases. During a typical Thermal Runaway course, three main flow scenarios are identified: 1. Under-expanded jets at opening due to the high pressure inside the battery, 2. Jet fires in case of ignition, 3. Explosions in case of delayed ignition. Being able to simulate these events can help to target safer battery designs at a minimal prototyping cost. This study thus aims at proposing a methodology to simulate failing Lithium-ion batteries-related combustion scenarios, using 3D reactive Large Eddy Simulation. The setup of such a simulation framework begins with the identification of the vent gases, their source and the way they can be modeled efficiently. An Analytically Reduced Chemistry kinetic scheme is then proposed to ensure the representativeness of the combustion processes at optimal costs when targeting 3D scenarios. After a setup phase in 1D, the validation of the 3D Large Eddy Simulation framework is performed on dedicated experimental setups developed and operated at the P' institute for jets and fires and obtained from the literature concerning explosions. Once validated, applications help to evaluate the capability of the simulation setup to target a variety of problems related to Lithium-ion, including effects of simple design choices on each phase of the Thermal Runaway. This work identifies the difficulties encountered when simulating Lithium-ion related accidents. Propositions are made to alleviate them, helping to advocate for the use of simulations during prototyping phases, to assert venting, fires or explosions of batteries.

Jury :

Nicolas Noiray : ETH Zürich – Referee

Epaminondas Mastorakos : University de Cambridge – Referee

Ronan Vicquelin : CNRS-Centrale Supélec- University Paris-Saclay – Examiner

Frédéric Ravet : Renault Group – Examiner

Marc Bellenoue : CNRS-ENSMA – Poitiers – Examiner

Gizem Okyay : SAFT Batteries – Bordeaux -Co-advisor

Thierry Poinsot : IMFT – CERFACS – Co-advisor

Florent Duchaine : CERFACS – Advisor