Characterization and experimental investigation of silicon nitride-based composite phase change materials for battery thermal management

In this study, different mass fractions of silicon nitride (Si3N4) were added to paraffin (PA)/expanded graphite (EG) to prepare a novel composite phase change material(CPCM). Thermal and chemical characterization of the CPCMs were conducted to assess their properties. The results indicated that adding 1 wt% Si3N4 was an optimal strategy, whose leakage rate at 40 degrees C and phase change starting temperature was lower and higher than that of PA/EG, respectively. Then, the cooling performance of the Si3N4/PA/EG CPCM with 1 wt% Si3N4 (denoted as CPCM1) was compared to PA/EG CPCM (denoted as CPCM0) and air cooling with a acrylic box. CPCM1 had heat dissipation and temperature uniformity property very close to CPCM0, but could obtain lower maximum temperature (Tmax) and better temperature uniformity than the air cooling with a acrylic box. For air cooling with a acrylic box, the Tmax and the maximum temperature difference (Delta Tmax) inside the battery at a discharge rate of 2C under 35 degrees C was 49 degrees C and 3.78 degrees C, respectively. However, the Tmax and Delta Tmax for CPCM1 cooling was only 40.7 degrees C and 1.37 degrees C, respectively, which was reduced by 16.9 % and 63.7 %, respectively. Thus, we could draw a conclusion that the Si3N4/PA/EG CPCM exhibited excellent ability to control maximum temperature and maximum temperature difference for the battery.