TY - JOUR A1 - Kusche, Christian A1 - Knaust, Christian A1 - Hahn, S.-K. A1 - Krause, U. T1 - Experimental investigations of the combustion efficiency for fire load calculations T1 - Experimetelle Untersuchungen der Verbrennungseffektivität für Brandlastberechnungen N2 - The amount of heat, which is released by fire loads during the combustion process, depends on the material characteristics, the ventilation conditions, the storage density and the distribution. To evaluate the structural stability of buildings in case of fire, the fire load has to be quantified. In Germany, the fire load is quantified by using the combustion factor m, while internationally the combustion efficiency χ is applied. Both factors assess the burning behavior of materials, but the determination is carried out in different ways. Since the testing facility was abolished fifteen years ago, it is not possible to determine the combustion factor m anymore. So, it should be found out, if the combustion efficiency χ is a convenient method to quantify the fire load under the consideration of the German standards. As a part of the research, combustion efficiencies χ were determined for eight materials in the cone calorimeter and the single burning item test at different heat fluxes. The values of the combustion efficiencies χ as well as the corresponding combustion factors m were discussed and compared to the values of the literature. The results show an influence of the testing facility on the combustion efficiency. The values of the combustion efficiency determined in the single burning item test were higher than the values from the cone calorimeter. N2 - Die Wärmefreisetzung einer Brandlast im Brandfall hängt von den Materialeigenschaften, den Ventilationsbedingungen, der Lagerungsdichte und der Verteilung im Brandraum ab. Die Festlegung der erforderlichen Feuerwiderstandsdauer in industriellen Gebäuden erfolgt auf Basis der Brandlast. In Deutschland dient der Abbrandfaktor m (m-Faktor) zur Berechnung der Brandlast, wohingegen international die Verbrennungseffektivität χ zur Berechnung verwendet wird. Zwar charakterisieren beide Faktoren das Abbrandverhalten von Stoffen, jedoch sind ihre Bestimmungsmethoden unterschiedlich. Seit der Abschaffung des letzten m-Faktor-Ofens vor mehr als 15 Jahren, ist die Bestimmung von m-Faktoren nicht mehr möglich. Daher soll untersucht werden, ob die Verbrennungseffektivität χ an Stelle des m-Faktors zur Berechnung der Brandlast im Rahmen deutscher Normen verwendet werden kann. Für diese Untersuchungen wurde die Verbrennungseffektivität χ von acht Stoffen im Cone Calorimeter und im Single Burning Item Test bei unterschiedlichen Wärmestromdichten bestimmt. Die ermittelten Werte der Verbrennungseffektivität χ wurden den bestehenden m-Faktoren gegenübergestellt und mit Werten aus der Literatur verglichen. Die Untersuchungen haben ergeben, dass die Prüfapparaturen zu unterschiedlichen Verbrennungseffektivitäten führen. Die Werte aus der Messung des SBI waren höher als die des Cone Calorimeters KW - Combustion efficiency KW - Combustion factor KW - Fire load density KW - Cone calorimeter KW - Single burning item test PY - 2015 DO - https://doi.org/10.3139/120.110795 SN - 0025-5300 VL - 57 IS - 10 SP - 843 EP - 849 PB - Carl Hanser Verlag CY - München AN - OPUS4-38738 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hahn, S.-K. A1 - Rost, M. A1 - Kusche, Christian A1 - Knaust, Christian A1 - Krause, U. T1 - Dokumentation der Entwicklung des m-Faktors und neuer Aspekt der Verbrennungseffizienz T1 - Structural fire protection in industrial buildings - development of the m-factor and new aspect of the combustion efficiency N2 - Vor dem Hintergrund der Zurückziehung der DIN 18230 Teil 2 zur Bestimmung des m-Faktors von Materialien für die Brandlastbewertung im Industriebau müssen neue Wege gefunden werden, wie das Abbrandverhalten alternativ quantifiziert werden kann. Der Beitrag fasst die Entstehung und die Entwicklung der Bestimmungsweise von Abbrandfaktoren zusammen und gibt Ausblick auf eine neue Möglichkeit zur Bewertung von Brandlasten, die Verbrennungseffizienz. KW - Abbrandfaktor KW - DIN 18230 KW - Indrustriebau KW - Brandschutz im Brandlast KW - Verbrennungseffizienz PY - 2017 DO - https://doi.org/10.1002/bate.201700020 SN - 0932-8351 SN - 1437-0999 VL - 94 IS - 6 SP - 337 EP - 343 PB - Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG CY - Berlin AN - OPUS4-40962 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tschirschwitz, Rico A1 - Bernardy, Christopher A1 - Wagner, Patrick A1 - Rappsilber, Tim A1 - Liebner, Christian A1 - Hahn, S.-K. A1 - Krause, U. T1 - Harmful effects of lithium-ion battery thermal runaway: scale-up tests from cell to second-life modules N2 - For a comprehensive safety assessment of stationary lithium-ion-battery applications, it is necessary to better understand the consequences of thermal runaway (TR). In this study, experimental tests comprising twelve TR experiments including four single-cell tests, two cell stack tests and six second-life module tests (2.65 kW h and 6.85 kW h) with an NMC-cathode under similar initial conditions were conducted. The temperature (direct at cells/modules and in near field), mass loss, cell/module voltage, and qualitative vent gas composition (Fourier transform infrared (FTIR) and diode laser spectroscopy (DLS) for HF) were measured. The results of the tests showed that the battery TR is accompanied by severe and in some cases violent chemical reactions. In most cases, TR was not accompanied by pregassing of the modules. Jet flames up to a length of 5 m and fragment throwing to distances to more than 30 m were detected. The TR of the tested modules was accompanied by significant mass loss of up to 82%. The maximum HF concentration measured was 76 ppm, whereby the measured HF concentrations in the module tests were not necessarily higher than that in the cell stack tests. Subsequently, an explosion of the released vent gas occurred in one of the tests, resulting in the intensification of the negative consequences. According to the evaluation of the gas measurements with regard to toxicity base on the “Acute Exposure Guideline Levels” (AEGL), there is some concern with regards to CO, which may be equally as important to consider as the release of HF. KW - Large-scale tests KW - Lithium-ion battery KW - Gas emission KW - Thermal runaway KW - Consequences PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579054 DO - https://doi.org/10.1039/D3RA02881J SN - 2046-2069 VL - 13 IS - 30 SP - 20761 EP - 20779 PB - Royal Society of Chemistry (RSC) CY - Cambridge, UK AN - OPUS4-57905 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Amano, K. O. A. A1 - Hahn, S.-K. A1 - Butt, N. A1 - Vorwerk, P. A1 - Gimadieva, E. A1 - Tschirschwitz, Rico A1 - Rappsilber, Tim A1 - Krause, U. T1 - Composition and Explosibility of Gas Emissions from Lithium-Ion Batteries Undergoing Thermal Runaway N2 - Lithium-based batteries have the potential to undergo thermal runaway (TR), during which mixtures of gases are released. The purpose of this study was to assess the explosibility of the gaseous emission from LIBs of an NMC-based cathode during thermal runaway. In the current project, a series of pouch lithium-based battery cells was exposed to abuse conditions (thermal) to study the total amount of gases released and the composition of the gas mixture. First, the battery cells were placed in a closed vessel, and the pressure and temperature rise inside the vessel were measured. In a second step, the composition of gases was analysed using a Fourier transform Infrared (FTIR) spectrometer. We found that the amount of released gases was up to 102 ± 4 L, with a clear dependence on the battery capacity. This study showed that the concentration of gaseous emissions such as carbon monoxide (CO), methane (CH4), ethylene (C2H4), ethane (C2H6), and hydrogen cyanide (HCN) increased with higher cell capacity. Of the five studied flammable gases, the maximum concentrations of carbon monoxide (16.85 vol%), methane (7.6 vol%), and ethylene (7.86 vol%) were identified to be within their explosible range. Applying Le Chatelier’s law, a calculated lower explosion limit (LEL) of 7% in volume fraction was obtained for the gas mixture. The upper explosion limit (UEL) of the gas mixture was also found to be 31% in volume. A filter comprising pyrobubbles was used for the removal of the studied gas components released during the thermal abuse. The investigation revealed that the pyrobubbles filter was highly effect in the removal of HCN (up to 94% removal) and CO2 (up to 100% removal). Herein, we report the dependency of the method of thermal runaway trigger on the measured maximum temperature. KW - Lithium-ion battery KW - Thermal runaway KW - Smoke gas emission KW - Gas explosion KW - Explosion limit PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576477 DO - https://doi.org/10.3390/batteries9060300 VL - 9 IS - 6 SP - 1 EP - 19 PB - MDPI CY - Basel, Switzerland AN - OPUS4-57647 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Amano, K.O.A. A1 - Hahn, S.-K. A1 - Tschirschwitz, Rico A1 - Rappsilber, Tim A1 - Krause, U. T1 - Experimental Investigation on Explosion Pressure Characteristics of Lithium-based (NMC) Pouch Batteries during Thermal Runaway N2 - Lithium ion batteries (LIBs) are prone to spontaneous and subsequent fire or explosion resulting from thermal runaway. The vented gases are not only toxic and flammable, their emission can also raise the surrounding pressure rapidly. In this study, characteristic variations of explosion pressure rise, rate of explosion pressure rise and 𝐾(sT)-value have been evaluated. The characteristic 𝐾(𝑠𝑇)-values were determined to evaluate the explosive behavior of LIBs during thermal runaway. The estimated values were compared to that of other explosive substances. T2 - Batterieforum Deutschland 2021 CY - Online meeting DA - 20.01.2021 KW - Pressure KW - Lithium KW - Thermal Runaway KW - Battery KW - Pouch PY - 2021 AN - OPUS4-52033 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yildirim, Arda A1 - Bühlmeyer, A. A1 - Hayash, S A1 - Haenle, J. C. A1 - Sentker, K. A1 - Krause, Christina A1 - Huber, Patrick A1 - Laschat, Sabine A1 - Schönhals, Andreas T1 - Multiple glassy dynamics in dipole functionalized triphenylene-based discotic liquid crystals revealed by broadband dielectric spectroscopy and advanced calorimetry – assessment of the molecular origin N2 - A selected series of dipole functionalized triphenylene-based discotic liquid crystals (DLCs) was synthesized and investigated in a systematic way to reveal the phase behavior and molecular dynamics. The later point is of particular importance to understand the charge transport in such systems which is the key property for their applications such as organic field-effect transistors, solar cells or as nanowires in molecular electronics, and also to tune the properties of DLCs. The mesomorphic properties were studied by polarizing optical microscopy, X-ray diffraction, and differential scanning calorimetry, which were compared to the corresponding unfunctionalized DLC. The molecular dynamics were investigated by a combination of state-of-the-art broadband dielectric spectroscopy (BDS) and advanced calorimetry such as fast scanning calorimetry (FSC) and specific heat spectroscopy (SHS). Besides localized fluctuations, surprisingly multiple glassy dynamics were detected for all materials for the first time. Glassy dynamics were proven for both processes unambiguously due to the extraordinary broad frequency range covered. The a1-process is attributed to fluctuations of the alky chains in the intercolumnar space because a polyethylene-like glassy dynamics is observed. This corresponds to a glass transition in a confined three-dimensional space. The a2-process found at temperatures lower than a1-process, is assigned to small scale rotational and/or translational in plane fluctuations of the triphenylene core inside distorted columns. This can be considered as a glass transition in a one-dimensional fluid. Therefore, obtained results are of general importance to understand the glass transition, which is an unsolved problem of condensed matter science. KW - Discotic Liquid Crystals KW - Broadband dielectric spectroscopy KW - Flash DSC KW - Specific heat spectroscopy PY - 2019 DO - https://doi.org/10.1039/c9cp03499d SN - 1463-9076 VL - 21 IS - 33 SP - 18265 EP - 18277 PB - RSC AN - OPUS4-48739 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -