Effect Analysis on Thermal Management of Power Batteries Utilizing a Form-Stable Silicone Grease/Composite Phase Change Material

Battery thermal management technology based on a phase change material (PCM) demonstrates outstanding performance. However, the low thermal conductivity and leakage of the PCM limit the application for battery thermal management. This paper proposes a polyethylene glycol/boron nitride/expanded graphite composite phase change material (CPCM). In view of the large contact resistance caused by the uneven surface of the CPCM, silicone grease was applied to the CPCM to prepare a silicone grease/composite phase change material (SCPCM). The SCPCM exhibits high shape stability and low contact thermal resistance in comparison with the CPCM. Furthermore, an active PCM thermal management system was designed to optimize the thermal management performance of the battery module. The experiment results indicated that the SCPCM thermal management showed a good thermal management performance at low discharge rates (1C and 2C), and the maximum temperature and temperature difference in the module were kept within 50 and 5 °C, respectively. However, at a discharge rate of 3C, the heat storage capacity of the SCPCM reaches saturation, and the heat dissipation capacity decreases. In addition, the water cooling coupled with PCM cooling (W-PCM) battery module always showed the best thermal performance. The W-PCM thermal management method can still effectively improve the thermal saturation problem of the PCM thermal management system after 10 charge and discharge cycles at 4C discharge rates.