Damage Analysis of Prismatic Battery Pack with Polyurea-Coated Carbon Fiber Reinforced Plastic Bottom Plate Due to Ground Impact

A polyurea coated CFRP laminated structure is designed to enhance the impact resistance of lithium-ion batteries due to ground impact. This paper documents numerical simulation to investigate the influence of polyurea coated CFRP battery pack bottom plate on mitigating battery damage under ground impact conditions. A novel three-dimensional polyurea coated CFRP finite element model including the hyper-viscoelastic model and orthotropic model is established for the analysis of impact response and damage behaviour in polyurea coated CFRP laminates. The impact peak force, energy absorption, and maximum crack length in the results of simulating polyurea coated CFRP laminated structure are within 5% of the experimental results. Based on the established three-dimensional polyurea coated CFRP finite element model, a new battery pack simulation model is developed. The battery module models innovatively adopts hybrid the homogenized battery module models and the detailed battery module models in this model. It enables accurate simulation of localized cells damage and failure during collisions while significantly improving computational efficiency. The punching process after the polyurea coated CFRP laminated structure perforation, the ensuing crack propagation of the plate as well as the local deformation modes of individual cells are clearly predicted by the global modelling. The battery shortening is recorded, which is an important indicator of electric short circuit of a battery cell and possible thermal runaway. A parametric study is carried out, and a few underlying rules are revealed, the front coating method lead 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 providing important clues on the design of protective structure of battery packs against ground impact.