Crash Simulation And Safety Analysis Of Vehicle Power Battery Pack

With the emergence of energy shortage and environmental pollution in various countries,new energy vehicles are gradually entering the mainstream market and are loved by the general public.Unlike fuel vehicles,the battery packs of new energy vehicles are more susceptible to the risk of fire and explosion when impacted by external forces than fuel tanks.As the number of new energy vehicles increases year by year,people are more and more concerned about their safety performance,and how to improve the safety performance of the battery pack of new energy vehicles after a collision is a topic worth studying.As a weak area of the vehicle,the side surrounds of the body are more concentrated and the collision area is more deformed in the side pillar collision condition,which is mainly investigated the safety of the bottom battery pack.At the same time,there is less research on the safety of the bottom battery pack in frontal 40% offset collision,more scholars focus on frontal 100% collision,but in frontal 40% offset collision condition,the excessive intrusion of the collision side usually threatens the safety of the battery pack.The test method for the forward scraped bottom collision was released in December 2021,so less research has been conducted on the safety of battery packs in this condition,but in this condition,the battery pack is in direct contact with the barrier,which has a large impact on the battery pack and is more likely to investigate the collision safety of the battery pack.The three conditions selected for this paper include frontal,side and bottom collisions,and the threat to the battery pack is high,which is very representative.In order to better fit the real-life crash form,the power pack is considered in the whole vehicle rather than just one battery pack alone.The finite element model of the whole vehicle for these three conditions is built by HyperMesh in conjunction with LS-DYNA,and the structural weaknesses are improved based on the simulation results and real vehicle tests.The main research elements of the thesis include:(1)Firstly,a brief overview of the regulations and theories involved in the paper is given.As the core component of a new energy vehicle,the battery pack layout is briefly discussed.(2)In order to improve the safety of the frontal 40% offset collision of this new energy vehicle,a finite element model for this condition was built in HyperMesh and LS-DYNA was used to explore the safety of the offset collision of the new energy vehicle,but after the real vehicle test,it was found that there were welding joint failures in many parts of the body,resulting in the overall stiffness and strength of the vehicle being reduced,and the battery pack shell was therefore hit by the left front wheel swing arm of the vehicle,In order to avoid this phenomenon,the finite element model was aligned with the test results to optimise the credibility of the model,and local strengthening was carried out to address the weak points,and then a real-world test was conducted to verify the feasibility of the solution.Risk of secondary accidents in the driver’s compartment.(3)As countries are paying more and more attention to the safety of the battery pack in the side impact condition of new energy vehicles,this paper also takes into account the harshness of this condition and strengthens the key components of the vehicle at the early stage of design.The results of simulation analysis and real-world tests show that the battery pack shell is slightly deformed in this condition,but it does not affect the safety of the internal battery module,and one side door can be opened smoothly after the test.(4)Considering that the battery pack is arranged at the bottom of the vehicle,the risk of fire caused by the collision of foreign objects on the road with the bottom of the battery pack,a bottom protection rod is designed to be arranged at the front of the battery pack,and a finite element model is established for the positive bottom scraping condition of the vehicle with reference to T/CASE 244-2021 standard.The simulation analysis shows that the Z-directional intrusion of the battery pack shell is less than the safety threshold,and the test results show that the structure can provide good frontal impact protection for the battery pack in the forward scraping condition.In this paper,the front,side and bottom collisions of the vehicle are selected as three conditions that pose great threats to the safety of the battery pack.The overall thinking of placing the battery pack in the vehicle is adopted.Based on collision regulations,the research method combining simulation and test is adopted to analyze the safety of the battery pack at the bottom,which has certain innovative and practical significance.It also plays an important reference role in the improvement design of other new energy models in these three working conditions.