关键词: 动力电池包；横梁-边框连接可靠性；多轴振动疲劳；焊接热影响区；计算机辅助工 程分析

Abstract: A standard pack of a light truck is failed after strength design verification (DV) test, with cracks of welds and profile base metal is found at the connection between the beam of internal module installation and the frame. Due to the limited internal space, the positions of the module and the battery management system (BMS) cannot be moved, and this problem needs to be solved under the current layout. This study experimentally investigates the impact of densely distributed welds on vibration-induced failures. Through a multi-scheme comparative analysis integrated with finite element simulation, three connection reconfiguration approaches are evaluated: scheme A: bracket-free, scheme B: welded-bolted hybrid, and scheme C, full bolted connection. The results demonstrate that replacing welds with bolted connections significantly mitigates stress concentration effects. The optimized design is rigorously validated via triaxial vibration bench testing, successfully passing vibration tests at twice the national standard requirements. It provides a solution for the compact structure design of high energy density battery pack.

Key words: power battery pack; beam-frame connection reliability; multi-axis vibration fatigue; weld heat-affected zone; computer aided engineering analysis