Preparation Of IGBT Module Substrate Material For High Speed Train And Finite Element Analysis Of Its Thermal Conductivity

With the rapid development of high-speed railway,the requirement of power system is higher and higher.IGBT is known as the “heart” of high-speed train,which controls the power system of locomotive,so it has a very high requirement for heat dissipation.The heat dissipation of IGBT module has always been a difficult problem.At present,people have made in-depth research on the structure of radiator,refrigerant and other aspects.In addition,the research on high thermal conductivity materials has always been an important part of scientific research.As a kind of heat dissipating material,high thermal conductivity material plays a key role in the conduction of resistance heat.Especially for high-power electronic devices,the importance of high thermal conductivity materials is particularly prominent.Graphene has an ultra-high thermal conductivity(TC)along its basin plane.However,the TC of graphene/metal composites was still far below the expectation due primarily to the lack of sufficient graphene alignment in the metal matrix.Herein,we reported an efficient route to prepare the graphene nano-platelet(GNP)/Cu composites with highly aligned GNPs by a vacuum filtration method followed by spark plasma sintering.Impressively,when the GNP fraction reached 35 vol%,a long-range and highly aligned GNP network was established within the Cu matrix,leading to a surprisingly high in-plane TC of 525 W/mK,which was 50% higher than that of Cu matrix and among the highest value ever reported for bulk graphene/metal composites.At the same time,we characterized the samples,including scanning electron microscopy,transmission electron microscopy,Raman spectroscopy and so on.Through SEM observation,it was found that GNPs shows a good dispersion state in copper matrix,and its surface orientation was highly consistent.The interface between GNP and copper was well bonded as observed by the TEM.It was found by Raman spectrum that the defects of graphene in the samples were very few.These results demonstrated that our strategy to construct a highly aligned graphene network could indeed achieve the remarkable in-plane TC enhancement in graphene/metal composites,and resulting composites may find application in electronic packaging that requires efficient directional heat transfer.For the purpose of verifying the difference of thermal conductivity between the composite and oxygen-free copper in the IGBT substrate,the thermal conductivity of the composite was simulated after the preparation of the material.The substrate was modeled by SolidWorks,and then simulated in ANSYS Workbench with material properties.In this paper,the finite element analysis was carried out on the substrate of oxygen-free copper material and composite material,and then the calculation results were compared.Firstly,the finite element analysis of the sample show that the thermal conductivity of the composite sample was better than that of the oxygen free copper sample.Then we simulated the substrate again.By comparing the temperature nephogram and the data,the composite material show obvious anisotropy in heat conduction.Next,we added heat conducting sheet and radiator on the substrate,and then we cut the substrate.We gave the composite material and oxygen-free copper material to the thermal conductivity slice and the substrate,and simulated and compared them.After calculation,it was found that the temperature of the chip has been significantly reduced.