This work aimed to analyze the behavior of the rear structure region of an electric bus in a rear collision situation and to create mechanisms capable of absorbing the energy generated by the impact, to guarantee the integrity of the batteries. These, when damaged in a collision, can release different types of flammable electrolytes, and even start a fire, creating a great risk to passengers and other people near to the vehicle. For this purpose, an impact absorber was developed to protect the batteries. Studies were carried out on rectangular cross-section profiles for programmed deformation, known as crash boxes (which aim to convert kinetic energy into deformation energy). Proposals were created based on concepts obtained in the literature and numerically evaluated through explicit numerical simulations based on other similar articles. From these studies it was possible to obtain higher values of energy absorption when compared to a square tube of the same cross-section. After the individual simulations of each crash box, the most effective proposal was applied to the structure together with the other components of the vehicle’s rear structure, these with the function of directing the residual energy to more rigid regions of the vehicle, such as the chassis stringers and its crossbeams, regions connected to the bus body structure. The complete impact absorber validation methodologies were developed specifically for this work based on CONTRAN Resolution No. 629 - Appendix II, which refers to the pendulum test, due to the fact that there are no standards for buses regarding safety of batteries in case of collision. The crash boxes applied to the structure reached an efficiency of approximately 45% of the kinetic energy that was imposed on the impact cell converted into strain energy. In addition, the vehicle was able to meet the proposed approval criteria for the absence of contact between the structure components and the batteries. The methodology was considered efficient in order to represent a collision of a small vehicle in the back of the bus.
Design and Analysis of an Impact Absorber for Battery Pack Protection in Electric Buses using Numerical Simulation
Sae Technical Papers
12th SAE BRASIL Colloquium on Suspensions and Road Implements & Engineering Exhibition ; 2023
2023-07-25
Conference paper
English
British Library Conference Proceedings | 2023
|Battery powered electric buses
Taylor & Francis Verlag | 1989
|Battery pack protection device and electric vehicle with battery pack protection device
European Patent Office | 2015
|