Feasibility and effectiveness of battery thermal management system based on melting temperature-gradient phase change material design for improved temperature adaptability

Practical application of a traditional battery thermal management system (BTMS) with only one kind of phase change material (PCM) is severely limited by its poor temperature adaptability, since latent heat of PCM only takes effect in the narrow melting range. In this work, a BTMS based on melting temperature-gradient PCM design is proposed to address temperature adaptability issues and realize effective heat dissipation over a wide ambient temperature range. A systematic numerical study is conducted to validate the feasibility and effectiveness of the novel fin-enhanced BTMS based on melting temperature-gradient PCMs composed of RT28HC, RT35HC, and RT44HC. In-depth investigations are made to analyze the mechanisms behind its unique thermal characteristics. Among all PCM combinations tested, the 28HC-35HC-44HC case demonstrated the best temperature adaptability across the 25–40 °C range. This is because its different phase-change materials activate sequentially as the ambient temperature changes, ensuring consistent performance. Extended research is carried out to examine the influences of fin number and PCM thickness, with the optimal values determined to be 12 and 6 mm, respectively.