Phosphorus-nitrogen based flame retardant polyurethane composite phase change materials for battery thermal safety system

Thermal energy storage with phase change materials (PCMs) plays an important role in thermal utilization and energy management. However, the low thermal stability and easy flammable of CPCMs are great challenges for accelerating PCM-based battery thermal management system. Herein, an innovative high flame-retardant and form stable Polyethylene glycol (PEG)/ Expanded graphite (EG) and Diphenylmethane diisocyanate (MDI) and Melamine (MA) with 9,10-dihydro-9-oxa-10-phospha-phenanthrene-10-oxide (DOPO) (PMDM) has been successfully prepared and utilized in square battery module. The PMDM2containing DOPO and MA with the ratio of 1:2can maintain superior stable shape without leakage after heating 5 h at 80 °C. Besides, the total heat release (THR) and peak heat release rate (PHRR) of PMDM2 are decreased to 322.8 kW/m 2 and 94.3 MJ/m 2 , respectively. Comparing with the PM-Module and PEA-Module, at 2C discharge rate after ten cycles, the maximum temperature and temperature differences of the battery module with PMDM2can be maintained below 55 °C and 5.5 °C, respectively. This research reveals that flame retardant CPCM with polyurethane structured can improve the fireproof and anti-leakage properties, which will offer an effective thermal safety solution for energy storage and other fields. The battery module with this designed CPCM can provide an effective approach of passive heat management system with these notable performances.