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Experimental Testing and Numerical Modelling of Thermal Runaway in 18650 Lithium-Ion Batteries
Thesis (MEng)--Stellenbosch University, 2026.
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| Format: | Thesis |
| Language: | English |
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Stellenbosch : Stellenbosch University
2026
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| _version_ | 1867614112413908992 |
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| access_status_str | Open Access |
| author | Pretorius, Lourens Badenhorst |
| author2 | Walls, Richard Shaun |
| author_browse | Pretorius, Lourens Badenhorst Walls, Richard Shaun |
| author_facet | Walls, Richard Shaun Pretorius, Lourens Badenhorst |
| author_sort | Pretorius, Lourens Badenhorst |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MEng)--Stellenbosch University, 2026. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/135925 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:46:51.765Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/135925 Experimental Testing and Numerical Modelling of Thermal Runaway in 18650 Lithium-Ion Batteries Pretorius, Lourens Badenhorst Walls, Richard Shaun Devine, Courtney Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering. Thesis (MEng)--Stellenbosch University, 2026. Pretorius, L. B. 2026. Experimental Testing and Numerical Modelling of Thermal Runaway in 18650 Lithium-Ion Batteries. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/e8fdb3b1-0a9a-4f82-b9f1-5504b2dd11d0 Lithium-ion batteries (LIBs) are essential for commercial energy storage due to their high energy density and efficiency, supporting the global shift toward greener energy. However, damaged or abused LIBs can undergo thermal runaway (TR), a rapid exothermic process causing high temperatures in seconds, and often resistant to conventional fire suppression systems. A deeper understanding of TR is vital for developing effective mitigation strategies. This research investigates TR behaviour in commercially available 18650 cylindrical LIBs and develops numerical models using ANSYS Fluent, validated through experimental data. As the first step in such testing in South Africa, this study establishes a foundation for local LIB research. Preliminary experiments tested six LIBs from two brands (LASA and Samsung) at varying capacities, with three at 50 % state of charge (SOC) and three at 100 % SOC per brand. Results revealed manufacturer influence on failure modes: LASA cells typically vented jet flames through positive cap safety vents, while Samsung cells ruptured, ejecting the combined internal layers and electrolyte (often referred to as the “jelly roll”). Capacity differences showed no clear impact. SOC affected TR intensity, referring to nature and fire behaviour of the LIB, with 100% SOC cells causing more structural damage than 50 % SOC. The sporadic nature of TR highlighted challenges in obtaining repeatable data. Refined tests, using improved methods and Samsung LIBs at 100 % SOC, included three cell-level and five pack-level (4x3 arrangement) experiments. Cell-level results showed maximum temperatures of 787 to 847 °C, ignition temperatures of 209 to 240 °C, and ignition times of 296 to 394 seconds, providing sufficient results for calibration of the numerical models. Pack-level tests indicated a 20 % propagation probability, with unmitigated TR likely consuming the entire pack. Numerical 2D modelling achieved comparable agreement with experimental data, serving as an initial tool for surface temperature prediction and risk assessment, while laying groundwork for 3D propagation models. Combined experimental and numerical insights provide a calibrated framework for characterising TR at cell and pack levels, reducing testing costs and risks, and advancing safer energy storage systems. Masters 2026-04-15T10:04:41Z 2026-04-15T10:04:41Z 2026-03 Thesis https://scholar.sun.ac.za/handle/10019.1/135925 en Stellenbosch University 132 pages application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Pretorius, Lourens Badenhorst Experimental Testing and Numerical Modelling of Thermal Runaway in 18650 Lithium-Ion Batteries |
| title | Experimental Testing and Numerical Modelling of Thermal Runaway in 18650 Lithium-Ion Batteries |
| title_full | Experimental Testing and Numerical Modelling of Thermal Runaway in 18650 Lithium-Ion Batteries |
| title_fullStr | Experimental Testing and Numerical Modelling of Thermal Runaway in 18650 Lithium-Ion Batteries |
| title_full_unstemmed | Experimental Testing and Numerical Modelling of Thermal Runaway in 18650 Lithium-Ion Batteries |
| title_short | Experimental Testing and Numerical Modelling of Thermal Runaway in 18650 Lithium-Ion Batteries |
| title_sort | experimental testing and numerical modelling of thermal runaway in 18650 lithium ion batteries |
| url | https://scholar.sun.ac.za/handle/10019.1/135925 |
| work_keys_str_mv | AT pretoriuslourensbadenhorst experimentaltestingandnumericalmodellingofthermalrunawayin18650lithiumionbatteries |