Homogeneous constitutive relationship of cylindrical lithium-ion batteries under quasi-static compressive loading

Abstract

In engineering applications such as electric vehicles and energy storage systems, the structural safety of cylindrical lithium-ion batteries is crucial, especially under external impact or compressive loads that may induce deformation or damage, affecting overall safety performance. However, certain difficulties exist in extracting the homogenization model due to its asymmetric positive and negative electrode structure. The existing homogenization models are usually obtained by certain assumptions and fitting of the load-displacement-deformation experiment data, which has deviation with the experimental results and lacks some universality. In this study, we design a loading apparatus capable of precisely measuring the relationship between the loading distance and the contact area between the battery and the support platform under quasi-static compression conditions. Thus, the construction of an improved constitutive model can be achieved based on the obtained experimental data. The reliability of this model is validated through finite element simulation, demonstrating high consistency between experimental and simulation results. This research proposes a novel experimental methodology and a theoretical model for evaluating the mechanical performance of cylindrical lithium-ion batteries under compressive loading, which provides a more accurate reference model for structural safety assessments and future model verification.