Analysis and Optimization of Fatigue Caused by Vibrations in the Quick-Replacement Battery Box for Electric Vehicles

Abstract

Quick-replacement battery technology has the advantages of eliminating mileage issues, extending battery life and reducing cost. The battery box plays an important role in carrying and protecting the on-board battery pack. However, fatigue life has not been well-established in changeable operating environments and driving conditions; hence, this knowledge gap is the focus of this paper. Here, SolidWorks (SolidWorks, Waltham, MA, USA) was used to establish a three-dimensional model of a quick-replacement battery box for electric vehicles, OptiStruct software (Altair, Detroit, MI, USA) was used for sweep frequency and random vibration analyses, and random vibration fatigue analysis was carried out using Ncode software (ANSYS, Pittsburgh, PA, USA). The quick-replacement battery box structure was then optimized according to the analysis results and lightweight targets. The results of sweep frequency and random vibration analyses showed that the maximum stress of a quick-replacement battery box is 39.058 Mpa. Compared with the allowable stress of the DC01 material at 150 Mpa, a significant margin is still present. The results of random vibration fatigue analysis showed that the minimum service life of a quick-replacement battery box is 5.740 × 1010, which meets the design requirements. Following optimization design, the maximum stress of a quick-replacement battery box was 71.197 Mpa, still meeting the allowable stress of the DC01 material at 150 Mpa and effectively alleviating the stress concentration. Furthermore, the optimized quick-replacement battery box was approximately 4 kg lighter. Therefore, optimization of the quick-replacement battery box is feasible and necessary. The results provide great theoretical and engineering significance for the design and optimization of quick-replacement battery boxes for electric vehicles.