Research on the high thermal conductivity composite phase change materials with graphite nanosheets for battery thermal safety

Composite phase change material (CPCM) as an efficient battery thermal management strategy has been widely utilized owing to its promising performance, but its thermal conductivity and stability still need to be improved in battery module. Herein, three different kinds of CPCM have been successfully prepared and utilized in battery module, which are composite with PEG, epoxy resin (ER), silver nanoparticles (AgNP) modified with dopamine hydrochloride (PDA) self-assembled on the surface of graphite nanosheets (GNS), denoted as PEE (PEG/ER), PEG(PEG/ER/GNS), and PEGA (PEG/ER/GNS/Ag), respectively. Among them, the AgNP with super-high thermal conductivity has been distributed on the surface of GNS to form laminated nanostructures, promoting the construction of thermal conduction network. The thermal conductivity and latent heat of CPCM are 3.1 W∙m−1∙K−1 and 105.8 J∙g−1, respectively. Furthermore, even under 35 °C ambient temperature, the application of PEGA for battery module can effectively control the maximum temperature below 52 °C and maintained a temperature difference within 6 °C at a 3C discharge rate, which is better than those of battery modules with PEE and PEG. It reveals that the battery module with designed high thermal conductivity CPCM can provide insights into the passive thermal management and other energy storage fields.