Structural Design Of Battery Pack For Electric Vehicle

As the number of electric vehicles in the world increases year by year,countries have issued corresponding regulations and standards to test the collision safety of electric vehicles.The battery pack,which is the main source of power for electric vehicles,is crucial in the study of collision safety.In terms of crash safety research,electric vehicles are more different from traditional fuel vehicles.During the collision,electric vehicles must not only meet the occupant collision safety standards,but also meet the unique standards of electric vehicles.For example,the battery pack cannot invade the occupant’s driving area during collision,and battery,leakage,fire,explosion,etc.cannot occur after the collision.Therefore,in order to improve the crash safety of electric vehicles.it is of great significance to study the crash safety of electric vehicle battery packs.In this paper,the battery pack structure is designed to deal with the problem of battery pack collision and fire in electric vehicle collision conditions.Using UG,ANSA,ANSYS,Hyperview and other software,based on the finite element collision theory and the 2018 version of C-NCAP regulations,a battery pack collision finite element model was constructed,and the designed battery pack was verified and optimized through two ways.First,a side impact simulation test was conducted on an independent battery pack that was not installed on the vehicle,and structural strength simulation was performed to determine the battery pack structure with better safety.Based on the simulation,according to the specific structure of the bottom of the vehicle model.the geometric model of the square battery pack structure was established using the three-dimensional software UG.Then,import the geometric model into ANSA software to pre-process the battery pack to establish the battery pack finite element model.Finally,Hypermesh/OptiStruct is used to perform a modal analysis on the designed battery pack to verify that the battery pack structure meets the vibration strength requirements.One is the 100%frontal and side impact simulation test of installing the battery pack on the car.According to the frontal collision requirements in the 2018 version of C-NCAP regulations,a 100%frontal collision simulation finite element model of electric vehicles was established,and the results of the simulation collision were analyzed through the comparison of energy,mass increase and real vehicle data verification.The analysis results show that the stress of the ears of the battery pack is concentrated,the collision acceleration is too large,and the cabinet is basically not deformed.By studying the influence of materials,thickness,materials,etc.on the lifting lugs,the optimal plan is determined.The comparison between before and after optimization shows that the stress of the lifting lug has been reduced,the acceleration is too large,and the optimization effect is not good.On the basis of the frontal collision simulation finite element model,combined with regulatory requirements,a side collision finite element model is established.By analyzing the state of the collision vehicle,the intrusion acceleration and intrusion speed during the battery pack collision,the deformation,stress,and suction of the battery pack To study the crash safety of battery packs.From the analysis results,it can be seen that the outer box of the automobile battery pack is deformed greatly during side collision,the stress is large,and the safety is poor,which does not meet the design requirements.Through the analysis of the material and thickness of the outer box of the battery pack,the optimization plan of the outer box of the battery pack is obtained.The optimization results show that the deformation of the external box of the battery pack is significantly improved,and all other items are in line with the requirements,and the optimization effect is good.Finally,according to the simulation and analysis of frontal collision and side collision,the simulation test is designed,and the optimal solution of the battery pack is obtained through the comprehensive analysis of TOPSIS.On the basis of the optimal solution,the parameters are reset,and the frontal and side impact simulations are performed again.From the simulation comparison,it can be concluded that during a frontal collision,the battery pack acceleration is reduced,the stress on the battery is greatly reduced,and the stress on the lifting ear is too large.The stress concentration has been significantly improved;during a side collision,all safety indicators of the battery pack meet the requirements,and the optimization effect is good.