Preparation And Thermal Properties Of Paraffin-Graphene Aerogel Composite Phase Change Materials

With the clear proposal of the "3060" dual-carbon goal,my country has begun to develop towards a diversified energy structure,in which clean,green and environmentally friendly new energy plays an important role.In this context,organic phase change materials with high latent heat value,especially paraffin wax,which is widely available and inexpensive,have been widely used in the booming new energy field and other energy-related fields.However,the phase change material itself also has problems such as low thermal conductivity and easy leakage of the liquid phase generated during the phase change,and its application and development are also restricted to a certain extent.In order to solve such problems of phase change materials,the research contents of this paper mainly include the following aspects:1.In view of the low thermal conductivity of phase change materials and the easy leakage of liquid phase,this paper uses a directional temperature field to prepare anisotropic graphene aerogels,and then adsorbs the phase change materials by vacuum impregnation to enhance the phase change materials.Thermal conductivity,improve the leakage of composite materials during phase transition,and improve the structural strength of composite materials.Scanning electron microscope(SEM)images showed a highly anisotropic internal porous structure inside the aerogels and composites.Moreover,as a porous framework,aerogel can effectively encapsulate paraffin,and at the same time improve the mechanical strength of the composite phase change material during phase change.In addition,the latent heat of phase change of the composite phase change material has an increase of 6.23% to 9.99%.However,the density of the reduced graphene oxide aerogel is too small,the high thermal conductivity network inside the composite material is not dense enough,and the thermal conductivity is not significantly improved.2.In view of the problems of reduced graphene oxide aerosol and its composite materials,a hybrid graphene hybrid aerogel is proposed to optimize the thermal properties and structural strength of the aerogel and its composite materials.The high thermal conductivity nano graphene sheets are introduced into the graphene oxide dispersion,and the high thermal conductivity nano graphene sheets can be embedded in the graphene oxide aerogel after freeze-drying.After the reduction,the density of the aerogel is further improved,and its mechanical strength is also considerably enhanced.A denser network with high thermal conductivity is formed inside the composite material,and the thermal conductivity of the material increases significantly.The mass fraction of the internal hybrid graphene aerogel of the strengthened composite phase change material can reach up to 5.03%.Compared with pure paraffin,the latent heat of phase transition is only lost by less than 5%,and the thermal conductivity is increased to 1.7 times that of paraffin..3.The thermal management platform of power battery was built to verify the actual effect of composite material on battery thermal management under various working conditions.The power battery has serious heat under high rate discharge.The 18650 power battery was assembled with the composite material prepared by the experiment.Through the simulation of different discharge conditions of 18650 battery,the thermal management effect of composite material was comprehensively considered.The experimental results show that the peak temperature and the temperature difference between positive and negative electrodes of the battery can be reduced by 18.18% and66.1% under the discharge condition of 6C rate...