| With the continuous rise of the national economy consumption index,the occupancy rate of residential vehicles continues to increase,the domestic automobile industry gradually develops and expands,and the energy issue and environmental protection issue become the focus of the whole society.The energy consumption and exhaust emissions of traditional cars aggravate the shortage of resources and the destruction of the environment.Therefore,new energy electric vehicles with energy-saving and environmental protection highlights have become an important development direction in the current automotive field.In order to improve the range of new energy electric vehicles,it is necessary to reduce the weight of vehicles through structural design and application of new lightweight materials.Fiber reinforced resin matrix composites as a lightweight material with good mechanical properties and remarkable effect of lightweight,has been widely used in auto industry at present,the battery pack as a key part of the protection battery components,for its lightweight and raising the electric vehicle battery life,reduce energy consumption,one of the important ways to improve the energy density.Based on the above background,this paper takes the composite car battery pack cover as the research object,the research content mainly includes:(1)based on the structure and mechanics of the LFT-D battery pack cover,the PCM process and structure reconstruction,the establishment of the numerical analysis model of the battery pack cover,the state of the bump,brake and sharp turn three road conditions to simulate,verify that the structure strength and stiffness meet the requirements.(2)Based on the structure and material of the product,the PCM process molding scheme is formulated and the corresponding parameter values are selected,the mold structure and the paving process scheme are designed,and the paving defects are optimized by opening the cut.(3)Based on the defects in the initial commissioning of the product,through 19 orthogonal tests and 24 sets of single-factor experiments to optimize the combination of process parameters,to detect whether the product’s air tightness,fire resistance and flame retardant compliance.The research results are as follows:(1)The PCM process plan is as follows: Cut cloth-lay-into the mold-molding-demoulding.By comparing the material properties,it can be concluded that: The thickness of the cover of the battery pack made by PCM process is only 1.2mm,and the overall weight is only 4.7kg.Compared with the LFT-D product,the weight of the cover of the battery pack is reduced by about 50%,and the tensile strength is increased by 9.8 times.(2)Through static and dynamic simulation under three different working conditions,it is concluded that the deformation of the structure is not more than 1mm when the battery cover is accelerated by 1g;Under the acceleration of3.5g,it does not exceed 3.5mm;The natural frequencies of the first ten order constrained modes are all greater than 27.78 Hz,and the structure design can meet the strength and stiffness requirements of the battery pack.(3)It can be seen from the simulation of layup that defects such as bridging,twisting and folding will occur in the fiber lay-up,and the lay-up optimization is completed by opening the shear opening for material lap to eliminate the defects.(4)After orthogonal experiment and single factor experiment optimization,the final process parameter combination applied to actual production is:mold temperature 155℃,mold pressing pressure 400 T,preheating time 30 s,pressure holding time 600 s,operation time 60 s,mold closing speed 25mm/s,which can realize mass production and the average pass rate is 96%.The study of this scheme has a certain reference value for the manufacture of similar products. |
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