Thermal Behavior of Lithium- and Sodium-Ion Batteries: A Review on Heat Generation, Battery Degradation, Thermal Runway – Perspective and Future Directions

Safety is a major challenge plaguing the use of Li-ion batteries (LIBs) in electric vehicle (EV) applications. A wide range of operating conditions with varying temperatures and drive cycles can lead to battery abuse. A dangerous consequence of these abuses is thermal runaway (TR), an exponential increase in temperature inside the battery caused by the exothermic decomposition of the cell materials that leads to fire and explosion. It is imperative to develop methodologies to accurately predict and mitigate thermal runway. Sodium-ion batteries (SIBs) are inherently safer than LIBs. In addition to offering better safety, SIBs are gaining momentum due to the abundance and low cost of their raw materials compared to the limited lithium resources and high cost of elements such as cobalt, copper, and nickel used in LIBs. However, the challenge of low energy density impedes the maturation of sodium-ion technology to the same level as lithium-ion technology. There are additional challenges to the acceptability of sodium-ion batteries due to the poor sodium kinetics during insertion reactions, leading to rapid material degradation. Additionally, the higher solubility of the solid electrolyte interface (SEI) observed in the case of SIBs may lead to undesired side reactions, causing increased heat generation. This paper presents a comprehensive review of the heat-release mechanisms, their differences, and prediction methodologies for the two battery chemistries. Various experimental and modeling approaches for TR detection from the literature are reviewed. Future research directions toward the development of a battery management system (BMS) with the capability to identify the precursors to thermal runaway and implement mitigation strategies are also discussed.