Crashworthiness Design for an Electric City Car against Side Pole Impact

Abstract

Abstract. Electric vehicles are increasingly popular as an alternative to fossil fuel vehicles. The presence of batteries and electric motors poses different risks in collision accidents. The deformation of the batteries could spark a fire or explosion that in turn could endanger the passengers. The prototype of an Indonesian electric city car is currently being developed, which includes a battery pack located underneath the passenger compartment and electric motors in the front compartment. A crashworthiness design against side pole impact, in accordance with the Euro NCAP standard, was simulated numerically. In order to reduce the risk of battery explosion, an impact energy absorbing structure is proposed for implementation at the sides of the batteries. The structure of the four-passenger hatchback electric city car was modeled using all-shell elements with material properties for common automotive application and analyzed using the finite element method with dynamic plasticity capability. For the preliminary design, the minimum deformation of the batteries that can cause battery explosion was used as the failure criteria. From a number of design alternatives, the use of aluminum foam as impact energy absorber produced sufficient protection for the battery pack against side pole impact, hence effectively reducing the risk to an acceptable limit.

Lessons from the Electric Vehicle Crashworthiness Leading to Battery Fire

“…Results found a significant reduction on occupant compartment acceleration when using battery packs as energy-absorption components. Setiawan and Salim [82] presented FEM model to examine the performance of energy absorbing materials for securing the battery pack against the oblique side pole crash at 32 km/h. The use of aluminum foam as a filler for the door sill structure, showed an adequate battery pack deformation of 9.4 mm compared to the 15.3 mm limit.…”

“…Zhang et al [83] adopted China NCAP (C NCAP) for full wrap frontal crash tests at a speed of 50 km/h. Euro NCAP side pole tests with a test speed of 29 km/h were adopted in FEM models of Roland et al [77] and Schäffer et al [80], while Setiawan and Salim [82] simulated an oblique side pole test at 32 km/h. Regarding the EVs' fire incidents reported in Table 3 and their discussion provided in paragraph 2 of Section 5, the frontal crash speeds are 71 km/h (Guangzhou, China), 97 km/h (South Jordan, USA), 120 km/h (Mountain View, California and Northern Greece), 137 km/h (Broward County, Florida), 160 km/h (West Hollywood), 177 km/h (Merida, Mexico), and 185 km/h (Fort Lauderdale, Florida).…”

Vehicle occupant safety development with finite element method

“…The area of the lower instrument panel shall provide for the possibility of parallel contact of the knees on the instrument panel in accordance with the front crash requirements. The center console also often requires modifications due to side accident regulations [4].…”

Influence of Geometry in the Behavior of Disc-Shaped Mechanical Energy Absorbers for Agricultural Tractors

“…In this context, the analysis of foams of different compositions have led to a productive research activity: aluminum foam to minimize damage to the batteries of an electric vehicle in case of collision has been applied [13], and the increase in the energy absorption capacity of Al-Cu-Mg open-cell foams by heat treatment has been studied [14]. Additionally, an open-cell nickel foam-natural rubber hybrid materials has been analyzed, and it was concluded that its compression energy absorption capacity was higher than that of open-cell nickel foam and natural rubber [15].…”

“…More applied solutions to improve the energy absorption of safety devices in vehicles can be found in Setiawan and Salim [13], who developed an impact energy absorber, based on aluminum foam to protect the batteries of an electric vehicle. An energy absorber, in the event of an impact, combined with a mechanical fuse was presented by Oyan [27].…”