A review of thermal management systems of lithium-ion batteries used in electric vehicles

The increasing adoption of electric vehicles (EVs) has made the safe, efficient, and long-lasting operation of lithium-ion batteries a critical area of research. During operation, batteries are exposed to elevated temperatures, which can lead to performance degradation, capacity fade, and potential safety hazards, such as thermal runaway. Consequently, battery thermal management systems (BTMS) play a vital role in maintaining battery temperature within the optimal operating range (typically between 20 °C and 40 °C), thus ensuring reliable and safe operation. This study provides a comprehensive review of prevalent thermal management methods employed in EVs, including air cooling, liquid cooling, heat pipe-based cooling, and phase change material (PCM)-based cooling. The advantages, limitations, and application areas of each method are critically compared, and their effectiveness in thermal regulation is evaluated. Air cooling systems offer cost-effectiveness and design simplicity; however, their heat dissipation capacity is limited, particularly under high heat load conditions. Liquid cooling methods provide higher cooling efficiency but necessitate more complex designs and introduce potential leakage risks. Heat pipe-based cooling presents an effective solution due to its high heat transfer capability, contributing to improved battery temperature uniformity. PCMs offer passive cooling and potential energy savings; however, their inherently low thermal conductivity often necessitates integration with other active cooling techniques. The findings indicate that hybrid cooling systems, combining multiple methods, can achieve superior thermal management and a more uniform temperature distribution within the battery pack. Future research directions should focus on the development of advanced materials, such as novel PCMs with enhanced thermal conductivity, and optimized system designs, including microchannel cooling and advanced control algorithms, to further enhance BTMS efficiency and reliability in EVs, ultimately contributing to the wider adoption of sustainable transportation. • Various battery thermal management systems for electric vehicles are reviewed. • Air cooling, liquid cooling, heat pipe-based cooling, and phase change material-based cooling methods are analyzed. • Battery thermal management systems are compared in terms of efficiency, safety, and cost. • Hybrid cooling approaches are evaluated for enhanced battery performance. • Future research directions for improving BTMS efficiency are discussed