Research on the design and parameter optimization of hybrid thermal management system combing phase change material with liquid-cooling

Battery energy storage systems (BESS) are crucial to manage the variability of renewable energy. However, heat generated during battery charging and discharging can cause elevated temperatures, posing significant safety risks. Fortunately, Liquid-Cooling phase change material (PCM) hybrid thermal management system (TMS) can effectively reduce battery temperature and mitigate safety risks caused by heat generation. But the structure of the Liquid-Cooling system and the thermophysical properties of PCM affect the heat transfer of the hybrid TMS. In this study, a novel flexible composite PCM (ZES@PW) was developed, utilizing styrene-butadiene block copolymer (SEBS) as the structural scaffold, paraffin wax (PW) as the latent-storage medium, and a hybrid filler of ZIF-derived carbon/expanded graphite to synergistically boost thermal conductivity. ZES@PW demonstrates high heat storage efficiency (73.59%–78.98%), significantly enhanced thermal conductivity (107.55%–232.83%), excellent flexibility, and low contact thermal resistance. An experimental platform and model were established to optimize the temperature control performance of the liquid-cooled ZES@PW hybrid TMS in Li-ion soft packs. Results showed that for 1C/2C discharging conditions, the surface maximum temperature for battery with a decrease of 9.71K/23.63K. And three U-shaped bends structure was identified as the optimal design, three number of batteries in series was the optimal configuration, and the max liquid flow rate was 0.06/0.12 m/s for 1C/2C operating conditions. For ZES@PW, phase change temperature and enthalpy significantly affect the liquid phase rate and heat exchange. Thermal conductivity impacts the maximum temperature difference between the battery and ZES@PW. These findings can effectively guide the design of PCM-hybrid TMS.