Casting Defect Analysis And Improvement And Lightweight Design Of A New Energy Vehicle Battery Tray

In the context of "peak carbon dioxide emissions" and "carbon neutrality",the development of the new energy automobile industry is an effective way to alleviate the energy crisis,reduce greenhouse gas emissions,and reduce environmental pollution.It has become an important direction for the reform of the automobile industry.In order to improve the production qualification rate of a new energy vehicle battery tray,the paper used the method of combining software numerical simulation(by Anycasting)and casting experiment to study the types,distribution,causes,improvement plans of the defect of the battery trays produced by existing process,and to design a new low-pressure casting process for the battery tray,which obtained high-quality battery trays that could be continuously cast.At the same time,in order to reduce energy consumption and increase the cruising range of the new energy vehicle,the paper carried out a lightweight design for this type of new energy vehicle battery tray based on the TRIZ theory,and verified the rationality of the lightweight design through the ANSYS Workbench software mechanical simulation.The main conclusions are as follows:1)By counting the defect distribution of battery trays and observing the macro morphology and microstructure of the defect parts,it was concluded that the defect parts of the battery tray were mainly the threaded holes of the EDM frame,the threaded holes of the front beam,the side lifting lugs,the threaded holes of the rear beam,the front edge of the bottom surface,and the center beam threaded hole position.The types of defect were penetrating shrinkage cavity and shrinkage porosity,and the main cause of defect was the improper current low pressure casting process.The method of numerical simulation was used to compare the defect of the tray under different pouring temperatures,boost pressures,pouring runners,and cooling processes,and to propose an improvement plan of setting the pouring temperature to 710℃,widening the runners and adding a cooling system,which reduced the occurrence of defect effectively.2)To solve the problem of unstable production quality in the existing low-pressure casting process,through theoretical calculation,numerical simulation,and low-pressure casting production practice,the new low-pressure casting process research was carried out.It was concluded that under the "four-stage" filling,the pouring temperature of 710℃,the boost pressure of 60 k Pa,the holding time of 150 s,the three sets of cooling pipes,the external extrusion pin structure,the continuously casted tray had good mechanical properties,the X-ray inspection defect level did not exceed 3,and the porosity inspection met the D5/1.0 standard.3)In view of the problem that the large weight of the current battery tray affects the cruising range of the new energy vehicle,the weight of the middle beam,lifting lugs,stiffeners,flange edges,EDM frame and its explosion-proof valve,and bottom structure of the battery tray was reduced based on the TRIZ theory.The treatment reduced the weight by 15%.The mechanical analysis and verification of the weight-reduced battery were carried out by ANSYS Workbench,and it was concluded that the tray would not resonate with the new energy vehicle after assembly,and the maximum Von-Mises stresses of the tray under static force,random vibration and special working conditions were less than the allowable stresses.The structural strength of the lightweight tray is qualified.