Patel, Sana2026-06-172026-06-172026-05-19Patel, S. 2026. Multi-scale electrochemical-thermal modelling of a sodium-ion battery cell using the SPMe with a lumped thermal model. . .https://univendspace.univen.ac.za/handle/11602/3195M.Sc. in PhysicsThe escalating global demand for energy has raised questions regarding the sustainability, availability, and viability of energy sources. Consequently, renewable energy resources have gained significant attention owing to their environmental safety and abundant availability. However, owing to seasonal fluctuations in renewable sources, it is necessary to integrate efficient energy storage systems that can store energy during peak production hours and supply it when needed. For several decades, lithium-ion batteries have served as the primary energy storage technology for portable electronic devices and electric vehicles (EVs). However, their economic cost and geographical concentration have intensified interest in sodium-ion batteries (SiBs). Among various SiB chemistries, the Na3V2(PO4)2F3 (NVPF) cathode paired with a hard carbon (HC) anode is a promising electrode pair owing to its structural stability and high operating voltage, making it suitable for EV applications. This study investigated the electrochemical-thermal behavior of an NVPF/HC sodium-ion cell using a multiscale modelling framework based on the Single Particle Model with electrolyte (SPMe) coupled with a lumped thermal model and implemented in PyBaMM. The simulations were conducted across C-rates, ranging from C/15 to 3C and temperatures from -20 °C to 55 °C, to analyze voltage profiles, capacity retention, thermal response, and volumetric energy-power trade-offs. The model predicted a maximum discharge capacity of ~2.75 mAh at the lowest rate of C/15 across most operating temperatures. Capacity loss increased with increasing C-rate, delivering ~ 2.11 mAh at 1C, ~1.374 mAh at 2C, and ~0.94 mAh at 3C. At 55 °C ,the cell retained ~76 % of its capacity at 1C, ~51 % at 2C, and only ~42 % at 3C. The thermal effects were minimal at low C-rates but became significant at high rates, resulting in an increased overpotential. The volumetric Ragone plot showed energy and power densities at both low and high rates, and an optimal balance was observed at moderate discharge rates (i.e., C/2 to 1C). The electrode potential profiles indicated that the NVPF cathode dominated the initial discharge voltage, whereas at high currents, the potential rise of the HC anode limited the performance of the sodium-ion cell in EVs. This study provides guidance for battery engineers to understand the influence of the C-rate and temperature on sodium-ion batteries.enSodium-ion batteriesUCTDElectrochemical-thermal performanceDischarging rateThesisPatel S. Multi-scale electrochemical-thermal modelling of a sodium-ion battery cell using the SPMe with a lumped thermal model. []. , 2026 [cited yyyy month dd]. Available from:Patel, S. (2026). <i>Multi-scale electrochemical-thermal modelling of a sodium-ion battery cell using the SPMe with a lumped thermal model</i>. (). . Retrieved fromPatel, Sana. <i>"Multi-scale electrochemical-thermal modelling of a sodium-ion battery cell using the SPMe with a lumped thermal model."</i> ., , 2026.TY - Thesis AU - Patel, Sana AB - The escalating global demand for energy has raised questions regarding the sustainability, availability, and viability of energy sources. Consequently, renewable energy resources have gained significant attention owing to their environmental safety and abundant availability. However, owing to seasonal fluctuations in renewable sources, it is necessary to integrate efficient energy storage systems that can store energy during peak production hours and supply it when needed. For several decades, lithium-ion batteries have served as the primary energy storage technology for portable electronic devices and electric vehicles (EVs). However, their economic cost and geographical concentration have intensified interest in sodium-ion batteries (SiBs). Among various SiB chemistries, the Na3V2(PO4)2F3 (NVPF) cathode paired with a hard carbon (HC) anode is a promising electrode pair owing to its structural stability and high operating voltage, making it suitable for EV applications. This study investigated the electrochemical-thermal behavior of an NVPF/HC sodium-ion cell using a multiscale modelling framework based on the Single Particle Model with electrolyte (SPMe) coupled with a lumped thermal model and implemented in PyBaMM. The simulations were conducted across C-rates, ranging from C/15 to 3C and temperatures from -20 °C to 55 °C, to analyze voltage profiles, capacity retention, thermal response, and volumetric energy-power trade-offs. The model predicted a maximum discharge capacity of ~2.75 mAh at the lowest rate of C/15 across most operating temperatures. Capacity loss increased with increasing C-rate, delivering ~ 2.11 mAh at 1C, ~1.374 mAh at 2C, and ~0.94 mAh at 3C. At 55 °C ,the cell retained ~76 % of its capacity at 1C, ~51 % at 2C, and only ~42 % at 3C. The thermal effects were minimal at low C-rates but became significant at high rates, resulting in an increased overpotential. The volumetric Ragone plot showed energy and power densities at both low and high rates, and an optimal balance was observed at moderate discharge rates (i.e., C/2 to 1C). The electrode potential profiles indicated that the NVPF cathode dominated the initial discharge voltage, whereas at high currents, the potential rise of the HC anode limited the performance of the sodium-ion cell in EVs. This study provides guidance for battery engineers to understand the influence of the C-rate and temperature on sodium-ion batteries. DA - 2026-05-19 DB - ResearchSpace DP - Univen KW - Sodium-ion batteries KW - Electrochemical-thermal performance KW - Discharging rate LK - https://univendspace.univen.ac.za PY - 2026 T1 - Multi-scale electrochemical-thermal modelling of a sodium-ion battery cell using the SPMe with a lumped thermal model TI - Multi-scale electrochemical-thermal modelling of a sodium-ion battery cell using the SPMe with a lumped thermal model UR - ER -