Finite Element Analysis And Structural Optimization Design Of Battery Pack Enclosure

Battery pack as the core component of new energy vehicles has become a key factor affecting the performance and market competitiveness of new energy vehicles.From the past to the present,in the field of automotive product design has been focusing on high stiffness,light weight of the lightweight design of the route,resulting in lower manufacturing costs,low fuel consumption and other significant economic benefits and competitiveness.Similarly,now the battery pack pack design in the face of the national guidance and subsidy policy stimulus,is in urgent need of the monomer mass energy density to work harder,continuous technological innovation,to maintain their market competitiveness.Follow the development path of light weight and high energy density.At present,it is urgent to find a solution for the battery pack with high light weight and high energy density.The synthesis of new materials,new technology and CAE simulation optimization technology is precisely the three swords to overcome this problem.In the new materials and new technology filed,the battery pack enclosure made of carbon fiber composite material for manufacturing the battery pack,focusing on carbon fiber layer thickness and shape,set reasonable stacking sequence,the requirements for strength and modal to match the existing metal box in a variety of typical static and dynamic conditions,and strive to a substantial reduction of the total weight of the pack enclosure.In the optimization design of the battery pack enclosure,we should also pay attention to the application of traditional design experience and technology.The upper box cover as a package of battery case,its characteristic is not load.bearing,in addition to its own gravity,rarely by external force,there is no need to use complex and the relatively high cost of carbon fiber composite material.The basic design requirements of the system only need to meet the low order mode can avoid the road roughness generated by the excitation frequency can be.Therefore,the optimization of the upper cover of the box body is focused on the research,on the basis of not changing the material on the sheet metal stamping process mature,reasonable layoutand cover on the surface of the emboss structure for local processing,strengthen,improvement and cover the overall stiffness and low order modes,avoid the road surface excitation frequency.In the aspect of static stiffness,the original design of the battery pack box on the cover of the poor performance of the bumps and other typical working conditions,the maximum deformation of more than 20 mm,the large deformation caused by the upper cover collide with the battery module,there is a big security risk;in the static strength,the poor performance of the battery pack box under the original floor in the design,such as bumps in the typical working conditions,the maximum equivalent stress reaches 455.67 MPa,beyond the yield limit and strength limit of the material,prone to damage,causes the case to crack or tear;the dynamic stiffness,the original design of the battery pack box on the cover of the poor performance of the first order frequency is 13.657 Hz,resonance before the ten order occurred on the box cover,the upper cover of the box body show that the local stiffness is seriously insufficient,should be strengthened,proposed to strengthen the box cover,the first resonance frequency should be higher than 27.7 8Hz.Finally,the optimized battery pack enclosure deformation in the most extreme conditions is only 4.05 mm,the maximum equivalent stress is 136.9MPa,the first natural frequency is 32.5Hz,the static stiffness,dynamic stiffness and static strength performance is excellent,and the weight loss ratio reaches 66.61%,which is effective lightweight.