Research progress on efficient battery thermal management system (BTMs) for electric vehicles using composite phase change materials with liquid cooling and nanoadditives

The increasing demand for electric vehicles (EVs) has brought new challenges in managing battery thermal conditions, particularly under high-power operations. This paper provides a comprehensive review of battery thermal management systems (BTMSs) for lithium-ion batteries, focusing on conventional and advanced cooling strategies. The primary objective of this study is to assess and compare the effectiveness of various cooling approaches, including air-based, liquid-based, phase change material (PCM)-based, and hybrid systems. This review paper reveals that while traditional air- and liquid-based systems offer certain benefits such as simplicity and cooling efficiency, they are constrained by limitations in thermal conductivity and energy consumption. In contrast, PCM-based systems, despite their poor thermal conductivity, provide stable temperature regulation without requiring additional energy input. To overcome these limitations, the integration of thermal conductivity enhancers (TCEs) like carbon fibers, expanded graphite, and metal foams into PCMs significantly improves their performance. For instance, composite PCM (CPCM) enhanced with expanded graphite shows a marked improvement in thermal conductivity, increasing from 0.2 Wm⁻¹ K⁻¹ to 16.6 Wm⁻¹ K⁻¹, resulting in battery temperature reductions by up to 28%. Additionally, hybrid systems that combine active cooling with CPCMs, particularly when using nanoenhanced PCM with additives like graphene and metallic nanoparticles, demonstrate superior cooling efficiency, with temperature reductions of up to 50% compared to traditional systems. The uniqueness of this paper lies in its detailed comparison of the various BTMS strategies, including a thorough evaluation of hybrid systems that merge passive and active cooling techniques. We also explore the potential of nanoenhanced PCMs and hybrid CPCM systems, which offer significant advantages for high-power battery applications by providing both efficient heat dissipation and improved battery longevity. By synthesizing recent advancements in this field, this review highlights the most promising thermal management strategies, paving the way for future innovation in BTMS design for electric vehicles.