Experimental investigation of the flame retardant and form-stable composite phase change materials for a power battery thermal management system

An efficient battery thermal management system (BTMS) will undoubtedly promote the performance and lifespan of battery packs. In this study, a novel flame-retarded composite PCMs composed by paraffin (PA), expanded graphite (EG), ammonium polyphosphate (APP), red phosphorus (RP) and epoxy resin (ER) has been proposed for battery module. The thermophysical and flame retardant properties are investigated at both macro and micro levels. The results show that the proposed composite PCMs with an APP/RP ratio of 23/10 exhibit the optimum flame retardant performance. Besides, the APP/RP-based composite PCMs for 18,650 ternary battery module has also been researched comparing with air cooled and PCM with pure PA modes. The experimental results indicated that the fire retardant PCMs shown significant cooling and temperature balancing advantages for battery module, leading to a 44.7% and 30.1% reduction rate of the peak temperature and the maintenance of the maximum temperature difference within 1.36 °C at a 3 C discharge rate for 25 °C. Even at 45 °C, the temperature uniformity can still be controlled within 5 °C. Thus, this research indicates the composite PCM had good flame retardant and form stable properties, it would be utilized in BTMS, energy storage and other fields. • A novel flame retardant form stable composite phase change materials is proposed. • Ammonium polyphosphate and red phosphorus are investigated as flame retardant. • Composite phase change materials with flame retardant additives have heat endurance. • The synergistic flame retardant effect can obviously enhance thermal properties. • Composite phase change materials exhibit a good battery thermal management effect.