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Prognosis of the end-of-life of lithium iron phosphate batteries with application in large-scale electric buses
Poonah, B. 2025. Prognosis of the End-of-Life of Lithium Iron Phosphate Batteries with application in Large-Scale Electric Buses. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/dfb789a0-cdce-49d7-8c4e-ec7d4c897bd6
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| Format: | Thesis |
| Language: | English |
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Stellenbosch : Stellenbosch University
2025
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| _version_ | 1867614099355992064 |
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| access_status_str | Open Access |
| author | Poonah, Brandon |
| author2 | Strauss, J. M. |
| author_browse | Poonah, Brandon Strauss, J. M. |
| author_facet | Strauss, J. M. Poonah, Brandon |
| author_sort | Poonah, Brandon |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Poonah, B. 2025. Prognosis of the End-of-Life of Lithium Iron Phosphate Batteries with application in Large-Scale Electric Buses. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/dfb789a0-cdce-49d7-8c4e-ec7d4c897bd6 |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/132498 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:46:39.009Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/132498 Prognosis of the end-of-life of lithium iron phosphate batteries with application in large-scale electric buses Poonah, Brandon Strauss, J. M. Mwaniki, F. M. Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. Electric vehicles -- Batteries Battery management systems Buses, Electric--Power supply UCTD Poonah, B. 2025. Prognosis of the End-of-Life of Lithium Iron Phosphate Batteries with application in Large-Scale Electric Buses. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/dfb789a0-cdce-49d7-8c4e-ec7d4c897bd6 Thesis (MEng)--Stellenbosch University, 2025. ENGLISH ABSTRACT: The electrification of public transport vehicles is rapidly advancing due to its considerable environmental benefits and alignment with global carbon neutrality goals. However, this shift presents significant challenges, such as the need for trip scheduling and substantial infrastructure investments. While these practicalities are critical, the focus of this thesis is on a pivotal yet frequently overlooked factor: the aging of Lithium-ion batteries, which serve as electric vehicles' (EVs) primary energy source. Lithium-ion battery capacity declines inevitably, further accelerated by environmental conditions and end-user behavior. This study, therefore, investigates the specific aging mechanisms of Lithium Iron Phosphate (LFP) batteries to pinpoint primary causes of aging under standard operating conditions, with the aim of mitigating long-term impacts. To enable state of health (SoH) and early lifetime estimations, various models are reviewed to assess their applicability and constraints, especially under data-limited scenarios. The semi-empirical and equivalent circuit models (ECM) are identified as the most suitable low-complexity approaches. Additionally, the recent developments in data-driven models are examined for their capacity to improve SoH estimation and predict remaining useful life (RUL) by incorporating external factors, including driver behavior and environmental conditions. Considering the importance of data variety and availability, publicly accessible battery datasets are reviewed for their potential in real-world applications, noting their limitations to laboratory-generated conditions and usefulness primarily in early-life predictions. Historical field battery data, sourced from the battery management systems (BMS) of forklifts and reach trucks, is analyzed to address these limitations. Key challenges arise due to the minimal utility of raw field battery data for aging prognostics, prompting the development of specific algorithms in Python in order to reconstruct missing information. Furthermore, a modified coulomb counting model is proposed to estimate SoH labels over the historical field battery dataset. Insights from the historical data then facilitate the calibration of a semi-empirical model that aligns with observed SoH trends over time. The resulting SoH labels are compared to the semi-empirical model to verify the calibration, and the model is subsequently extrapolated to the end-of-life (EoL) condition. The estimated RUL of the battery is projected to extend approximately 11 years and 6 months, assuming minimal deviations in future operating conditions. AFRIKAANSE OPSOMMING: Die elektrifisering van voertuie wat vir openbare vervoer gebruik word, neem vinnig toe as gevolg van die aansienlike omgewingsvoordele en die doelwit om wˆereldwyd koolstofneutraliteit te bereik. Hierdie skuif bring egter beduidende uitdagings mee, soos die behoefte aan ritbeplanning en groot infrastruktuurbeleggings. Terwyl hierdie praktiese uitdagings van groot belang is, fokus hierdie tesis op ’n sleutelaspek wat dikwels oor die hoof gesien word: die veroudering van Litium-ioon-batterye, wat die primˆere kragbron van elektriese voertuie (EVs) is. Litium-ioon-batterykapasiteit neem onvermydelik af, wat verder vererger word deur omgewingstoestande en eindgebruikersgedrag. Hierdie studie ondersoek dus die spesifieke verouderingsmeganismes van Litium-ysterfosfaat (LFP)-batterye om die primˆere oorsake van veroudering onder normale bedryfstoestande te identifiseer, met die doel om die langtermyn-impakte te versag. Om die bepaling van gesondheidstoestand (SoH) en vroe¨e lewensduur-skatting moontlik te maak, word verskeie modelle hersien om hul toepaslikheid en beperkings, veral in data-beperkte scenario’s, te assesseer. Die semi-empiriese en gelykstaande kringmodelle (ECM) word as die mees geskikte lae-kompleksiteit benaderings ge¨ıdentifiseer. Daarbenewens word die onlangse ontwikkelinge in data-gedrewe modelle ondersoek vir hul vermo¨e om die bepaling van SoH te verbeter en oorblywende bruikbare lewensduur (RUL) te voorspel deur eksterne faktore soos bestuurdersgedrag en omgewingstoestande in ag te neem. Aangesien die verskeidenheid en beskikbaarheid van data belangrik is, word publiek toeganklike battery-datastelle hersien vir hul potensiaal in werklike toepassings, met die opmerking dat hierdie datastelle beperk is tot data wat in laboratoriumtoestande gegenereer is en hoofsaaklik bruikbaar is vir vroe¨e-lewe-voorspellings. Historiese veldbattery-data, verkry vanaf die batterybestuurstelsels (BMS) van vurkhysers en bereik vragmotors, word ontleed om hierdie beperkings aan te spreek. Belangrike uitdagings ontstaan weens die beperkte nut van rou veldbattery-data vir verouderingsprognose, wat die ontwikkeling van spesifieke algoritmes in Python vereis om ontbrekende inligting te rekonstrueer. Verder word ’n aangepaste Coulomb-telmodel voorgestel om SoH-etikette oor die historiese veldbattery-dataset te skat. Inligting uit die historiese data fasiliteer dan die kalibrasie van ’n semi-empiriese model wat ooreenstem met waargenome SoH-neigings oor tyd. Die resulterende SoH-etikette word vergelyk met die semi-empiriese model om die kalibrasie te verifieer, en die model word daarna uitgebrei tot die eind-van-lewe (EoL) kondisie. Die geskatte RUL van die battery word op sowat 11 jaar en 6 maande beraam, met die aanname dat toekomstige bedryfstoestande min sal afwyk. Masters 2025-06-10T07:13:23Z 2025-06-10T07:13:23Z 2025-03 Thesis https://scholar.sun.ac.za/handle/10019.1/132498 en Stellenbosch University xiii, 109 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Electric vehicles -- Batteries Battery management systems Buses, Electric--Power supply UCTD Poonah, Brandon Prognosis of the end-of-life of lithium iron phosphate batteries with application in large-scale electric buses |
| title | Prognosis of the end-of-life of lithium iron phosphate batteries with application in large-scale electric buses |
| title_full | Prognosis of the end-of-life of lithium iron phosphate batteries with application in large-scale electric buses |
| title_fullStr | Prognosis of the end-of-life of lithium iron phosphate batteries with application in large-scale electric buses |
| title_full_unstemmed | Prognosis of the end-of-life of lithium iron phosphate batteries with application in large-scale electric buses |
| title_short | Prognosis of the end-of-life of lithium iron phosphate batteries with application in large-scale electric buses |
| title_sort | prognosis of the end of life of lithium iron phosphate batteries with application in large scale electric buses |
| topic | Electric vehicles -- Batteries Battery management systems Buses, Electric--Power supply UCTD |
| url | https://scholar.sun.ac.za/handle/10019.1/132498 |
| work_keys_str_mv | AT poonahbrandon prognosisoftheendoflifeoflithiumironphosphatebatterieswithapplicationinlargescaleelectricbuses |