Lithium-ion batteries (Li-ion batteries) have become indispensable power sources in numerous applications, from portable electronics to electric vehicles and renewable energy storage systems. Their popularity stems from their high energy density, long cycle life, and relatively lightweight. However, one critical aspect that significantly impacts their performance, safety, and lifespan is their thermal behavior. The efficient operation of Li-ion batteries is closely tied to maintaining an optimal temperature range during charging, discharging, and storage. This essay delves into the intricate thermal behavior of lithium-ion batteries, exploring the factors affecting their temperature, the potential consequences of thermal imbalances, and the strategies to manage their thermal characteristics effectively.

Recently, Professor Md. Arafat Rahman (Department of Mechanical Engineering, Chittagong University of Engineering and Technology, Chittagong, Bangladesh) and his team published a paper titled “Comparative analysis of electrochemical behaviors of lithium-ion batteries using the dual potential MSMD battery models: case studies on various thermal conditions” in Future Energy Journal.

The study focuses on two electro-chemical models (Equivalent Circuit Model and NTGK) of a dual potential Multi-Scale-Multi-Domain Model (MSMD) Lithium-ion Battery and examines their behavior under different heat transfer methods and various charge rates (C-rates). The investigation aims to determine the maximum temperatures reached by these models under varying ambient temperatures and C-rates. The findings show that the maximum temperature rise due to natural convection is greater than that due to radiation in the Equivalent Circuit Model. However, the NTGK model exhibits a different trend, with radiation causing a higher temperature rise than convection in certain scenarios. The study concludes that the NTGK model generally performs better with radiation as the mode of heat transfer at ambient temperature (to read more, download this open-access paper).

The thermal behavior of Li-ion batteries is affected by various intrinsic and extrinsic factors. Intrinsic factors include the battery’s chemistry, design, electrode materials, electrolyte composition, and internal resistance. These factors influence heat generation during charging and discharging processes, as well as the battery’s overall thermal stability. Extrinsic factors encompass ambient temperature, cooling systems, heat dissipation mechanisms, and charging/discharging rates. The combination of these factors can lead to significant temperature variations, affecting battery performance and safety.

Temperature fluctuations beyond the ideal operating range can have severe consequences for Li-ion batteries. High temperatures can accelerate chemical reactions within the battery, leading to thermal runaway, degradation of electrode materials, and ultimately reduced cycle life. On the other hand, low temperatures can increase internal resistance, limiting the battery’s power output and efficiency. Thermal imbalances may also trigger electrolyte decomposition and the formation of solid-electrolyte interface (SEI) layers, which affect overall battery performance. As the demand for Li-ion batteries continues to rise, a deeper understanding of their thermal behavior remains essential for unlocking their full potential while maintaining safety and longevity.