Optimization and performance analysis of a battery thermal management system combining piped liquid cooling and phase change material

To address heat accumulation and uneven temperature distribution in battery packs, this study proposes a hybrid battery thermal management system (BTMS) integrating piped liquid cooling with phase change material (PCM) cooling. Structural parameters, PCM types and compatibility, liquid cooling inlet conditions, and performance under extreme operating conditions were systematically investigated using the finite element simulations. The results indicate that the staggered arrangement (SA) of the batteries reduces the maximum temperature ( T max ) by 1.38 % and 5.15 % at 1 C and 2 C discharge rates, respectively, compared to the regular arrangement (RA). Additionally, the maximum temperature difference ( △T max ) at 2 C discharge decreases by 14.46 %. The combined cooling effects of battery spacing ( L ) and pipe diameter ( D ) reveal that both T max and PCM liquid phase fraction ( f ) decrease as L (1–5 mm) and D (1–4 mm) increase. The variation of △T max with L and D exhibits distinct patterns at different f . RT35HC provides better temperature uniformity than n-Octadecane, although it results in a higher T max . Under ambient temperature, the SA-2&4 configuration with n-Octadecane achieves the highest BTMS effectiveness factor ( ξ ), with T max = 39.09 °C and △T max = 4.52 °C. Under extreme high and low temperature conditions, fluctuating inlet velocity and temperature result in T max values of 40.91 °C and 44.39 °C, and △T max values of 4.31 °C and 3.96 °C, respectively, indicating robust heat dissipation performance. This study integrates structural parameters, materials, and operating conditions into a unified framework, offering both theoretical insights and practical guidance for advancing multidimensional BTMS design. Notably, system performance was evaluated across a broad temperature range (−30 °C–45 °C), directly reflecting real-world electric vehicle operating conditions, which is often overlooked in previous research. • Hybrid BTMS combines piped liquid cooling and PCM for better LIBs thermal control. • BTMS SA improves temperature uniformity, lowering the max battery temperature. • Battery spacing and pipe diameter optimize cooling and latent heat efficiency. • n-Octadecane outperforms RT35HC, offering higher thermal efficiency in the system. • Fluctuating inlet conditions in extreme temperatures ensure stable battery operation.