Experimental study on nano-encapsulated inorganic phase change material for lithium-ion battery thermal management and thermal runaway suppression

Although widely used in the thermal management of lithium-ion batteries, organic phase change material (PCM) with flammability has been reported to aggravate the fire risk and heat hazards of battery thermal runaway (TR). To reduce the fire risk of PCM during battery TR, an encapsulated inorganic PCM (EIPCM) was synthesized by a nano-encapsulation method of interfacial polymerization in this study. Na2HPO4·12H2O was used as the inorganic core material and silica was adopted as the encapsulated matrix to reduce the inherent defects. The synthesized EIPCM was characterized by a series of tests, demonstrating good phase change properties and thermal stability. The melting temperature of the EIPCM was measured as 51 °C associated with the latent heat of 111.69 kJ/kg. The thermal management effects of EIPCM were further investigated on battery modules at various discharge rates. The results show that EIPCM exhibited good cooling performance, leading to a 23.7% reduction of the peak battery temperature from 86.6 °C to 66.1 °C at a high discharge rate of 3C, and the temperature difference was kept within 3 °C. The TR behavior of batteries with IPCM was further explored, and the results indicate that EIPCM could delay the occurrence of TR by 495 s and decrease the peak surface temperature of the battery by 194 °C. With the nonflammable EIPCM, the fire of TR showed rapid extinction, protecting the batteries from heavier fire hazards. It is also found that EIPCM could inhibit the heat propagation of TR. The prepared EIPCM in this work with good thermal management effects and TR suppression performance has great prospects in practical battery applications, energy storage and other fields.