Damage Analysis of Prismatic Battery Pack with Polyurea-Coated Carbon Fiber Reinforced Plastic Bottom Plate Due to Ground Impact
Wenhong Ao, Luyang Wang, Chenghao Ma, Qing Zhou, Yong XiaA polyurea-coated carbon fiber reinforced plastic (CFRP) laminated structure is designed to enhance the impact resistance of lithium-ion batteries against ground impact. This paper presents a numerical simulation to investigate the influence of a polyurea-coated CFRP battery pack bottom plate on mitigating battery damage under ground impact conditions. A novel three-dimensional finite element model of the polyurea-coated CFRP laminate, incorporating a hyper-viscoelastic material model for the polyurea coating and an orthotropic model for the CFRP, is established to analyze the impact response and damage behavior of the laminate. The simulated impact peak force, energy absorption, and maximum crack length of the polyurea-coated CFRP laminate are all within 5% of the experimental results. Based on this validated three-dimensional model, a new battery pack simulation model is developed. The battery module model innovatively adopts a hybrid approach that combines homogenized battery module models and detailed battery module models, enabling accurate simulation of localized cell damage and failure during collisions while significantly improving computational efficiency. The punching process after perforation of the polyurea-coated CFRP laminate, the subsequent crack propagation of the plate, and the local deformation modes of individual cells are clearly predicted by the global model. Battery shortening is recorded as an important indicator of internal short circuits and potential thermal runaway. A parametric study is carried out, and several underlying rules are revealed: the front coating method leads to a greater reduction in battery damage, and the stiffness–toughness interplay between the polyurea coating and the carbon fiber composite is identified as a critical factor governing battery damage. This study provides important insights for the design of protective structures for battery packs against ground impact.