Study on Springback Testing of Ultra-Thin Titanium Bipolar Plates in Stamping Forming Based on Micro/Mesoscopic Scale Effects

Abstract Hydrogen fuel cells are widely regarded as promising for applications in automotive and unmanned aerial vehicle industries due to their high efficiency, lightweight, and low pollution. As a core component of fuel cells, the manufacturing precision of bipolar plates directly impacts battery performance. Metallic bipolar plates, particularly those made of pure titanium, have become a research focus owing to their excellent electrical conductivity, corrosion resistance, and high strength-to-weight ratio. However, pure titanium sheets are prone to springback during stamping, which affects forming accuracy. In this study, the effects of grain size, orientation, and forming angle on the micro-bending springback behavior of pure titanium sheets were systematically investigated through a combination of experiments and numerical simulations. Experimental results indicate that the springback angle initially decreases and then increases with increasing grain size, with significant differences observed among samples of different orientations. A numerical model based on the crystal plasticity finite element method successfully predicted the springback behavior, with simulation results deviating from experimental data by less than 8%. This study provides theoretical insights for optimizing the precision forming process of pure titanium bipolar plates and offers practical references for their application in hydrogen fuel cells.