Review on the numerical modeling of fracture in active materials for lithium ion batteries

Lithium ion batteries are one of the most widespread energy storage systems, but they still suffer some weak points, such as safety, limited energy density, and cycle life. The latter is caused by electrochemical and mechanical damaging mechanisms. The mechanical damaging mechanisms and their interplay with electrochemistry are reviewed in this paper. Lithium ions are inserted and extracted in the active materials of electrodes during battery operation, causing the deformation of the electrode microstructure. The deformation causes stresses and fractures ultimately, inducing electrochemical reactions on the crack surfaces, which lead to performance decay, such as loss of capacity and power. Then, proper mechanical models are needed to evaluate stress and crack propagation during battery operation. This review aims to give a comprehensive explanation of the following subjects: (a) The most general electrochemical–mechanical and transport models for intercalation materials; (b) Fundamentals of fracture mechanics; (c) Numerical implementation of fracture mechanics models applied to lithium ion batteries, covering the different approaches used in literature to estimate fracture in static and dynamic conditions; (d) Summary of the results of fracture mechanics models for lithium ion batteries; (e) Degradation models based on fracture mechanics.