TY - CONF A1 - Hahn, Sarah-K. A1 - Tschirschwitz, Rico A1 - Amano, Kofi Owusu Ansah A1 - Gimadieva, Elena A1 - Krause, Ulrich T1 - A Study on Thermal Runaway Propagation in Battery Modules Assembled from Pouch Cells N2 - Thermal runaway reactions were studied in arrangements from single battery cells with energy capacities of 2.5 Ah (9.25 Wh) to battery modules up to 6.85 kWh. All cells were pouch cells of the Li-ion NMC type and the modules were composed of such. Abuse was triggered either by overcharging or thermally by attaching a heat source (heating plate or glow plug) to the cells. Experiments with single cells or assemblies of two to four cells were undertaken in closed autoclaves. Samples of the gas released from the cells during the runaway were extracted and analysed using a Fourier-transformed infrared spectrometer (FTIR). In some experiments pressure peaks up to 7 bar (g) were observed which could not be explained by the gas release alone. Obviously, secondary explosions took place. Thermal runaway propagation was studied with and without an insulation layer between the battery cells. Several materials and combinations of them were tested as insulations: hollow glass spheres (Pyrobubbles®), phase change materials (PCM) and intumescent materials. Experiments showed that already layers of 10 to 20 mm of insulation effectively prevented the propagation of a thermal runaway. In addition to the experiments, a mathematical model was developed for studying numerically the heat transfer through arrangements of multiple battery cells and also the effect of insulation layers. This model was implemented into the commercial finite-element software package COMSOL Multiphysics®. The simulations confirmed the experimental findings that already quite thin insulation layers between cells or modules effectively delay or even suppress the propagation of the thermal runaway. T2 - EUSAS conference "Addressing the Fire Risks of Electromobility" CY - Frankfurt am Main, Germany DA - 10.05.2023 KW - Thermal Runaway KW - Consequences KW - Electrical Energy Storage KW - Gas release KW - Lithium-ion battery PY - 2024 UR - https://eusas.eu/publications/eusas-journals VL - 15 SP - 43 EP - 50 PB - EUSAS e.V. (European Society for Automatic Alarm Systems e.V.), Universität Duisburg-Essen, Dept. Nachrichtentechnische Systeme CY - Duisburg AN - OPUS4-61598 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Amano, Kofi Owusu Ansah A1 - Tschirschwitz, Rico A1 - Gimadieva, Elena A1 - Köhler, Florian A1 - Krause, Ulrich T1 - Thermal runaway and explosibility of the gas release from 18650 sodium-ion cells of NFM chemistry N2 - The present study investigates the thermal runaway behaviour and explosibility of the gas mixture released from sodium-ion batteries (SIBs). A total of 30 tests comprising two test series were performed using 18650 SIBs with a NaNi1/3Fe1/3Mn1/3O2 (NFM) chemistry. The cells of SOC level = 0 %, 25 %, 50 %, 75 % and 100 % were subjected to thermal abuse inside a 10 L pressurized reaction vessel. In test series 1, the tests were performed in an air atmosphere. In test series 2, an inert atmosphere was used. First, the total amount of gas released from the SIBs was calculated based on the temperature and pressure measured in the reaction vessel. Subsequently, a gas composition analysis was performed using a Fourier-transformed infrared (FTIR) spectrometer. This study revealed that the thermal runaway in SIBs could be categorized into four phases. At the onset of thermal runaway, the thermal runaway-induced explosion of the cells resulted in a rate of temperature rise ranging from 2 K/s to 70 K/s. The investigation further revealed a peak reaction temperature of 415 ◦C and a maximum pressure of 4 bar could be reached at thermal runaway in the 10 L vessel. The gas release of up to 5 ± 0.3 L (4 ± 0.2 L/Ah, 1.3 ± 0.1 L/Wh) from test series 1 and 2.4 ± 0.2 L (2 ± 0.1 L/Ah, 0.53 ± 0.04 L/Wh) from test series 2 showed a dependence on SOC and failure environment used. By applying Le Chatelier's mixing rule, the measured gas release from the air atmosphere showed a calculated lower explosion limit and upper explosion limit values of 4.8 % and 24 % in volume fraction, respectively. KW - Sodium-ion battery KW - Thermal runaway KW - Gas release KW - Gas explosion KW - Explosion limit PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631782 DO - https://doi.org/10.1016/j.est.2025.116614 SN - 2352-152X VL - 122 SP - 1 EP - 16 PB - Elsevier Ltd. AN - OPUS4-63178 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -