Research On Thermal Management Of Phase Change Cooling For Power Battery Based On Data Fusion

With the rapid development of electric vehicles,the frequent occurrence of electric vehicle fire accidents has caused people to question the safety of electric vehicles.And the development and research of power battery thermal management systems have gradually been paid attention by researchers.In this paper,18650 lithium-ion battery is selected as the research object,and the thermal management of phase change cooling for vehicle power lithium-ion battery is studied by the combination of simulation calculation method based on data fusion technology and experimental verification.Firstly,the working principle of lithium battery was analyzed and the thermal model of the battery was established.The temperature rise experiment of the single cell was carried out to get the temperature rise law in the discharge process of the single cell.Secondly,the battery parameters were identified through HPPC experiments,and the Extended Kalman Filter algorithm was used to establish the 18650 battery cell internal resistance-SOC fitting model to obtain the battery internal resistance-SOC relationship based on the data fusion theory.And UDF battery heat source program was written,which was imported into CFD software for simulation,to verify the feasibility of the simulation,and lay the foundation for thermal management simulation of composite phase change material battery.Finally,the composite graphite paraffin phase change materials were prepared,and the effects of different nano particles on the thermophysical properties of the phase change materials were compared.The effects of composite phase change materials on battery thermal management were studied by combining experiments and simulation calculation methods.The effects of composite phase change materials on the physical properties of the composite phase change materials and battery layout on battery cooling were compared.And the thermal management scheme of phase change cooling for power battery was proposedThe results show that the thermal conductivity and latent heat of the composite phase change material can be improved by adding a certain amount of nano particles into the graphite paraffin,which is helpful to enhance effect of the composite phase change material on the battery thermal management.The 18650 battery used in this project had a 6 mm cell spacing in the composite phase change material,which was best arranged in a sequential manner.Compared with the heat management scheme of air cooling and phase change cooling combined with air cooling,the fin phase change cooling structure designed in this project did not need to be equipped with air cooling device,and can still carry out good heat management when the battery pack discharged at 3C constant current multiple rate in 40?high temperature environment,and can obtain good temperature equalization effect,which can avoid the heat runaway caused by the high internal temperature of the battery cell.