Lithium-ion batteries (LIBs) have played an increasingly dominant role in the current mobile society. Due to the risky safety testing procedure, ultra-rigorous demands of the testing facility, and complicated multiphysics nature of the safety issues, lack of high-fidelity models to describe the safety behaviors of lithium-ion batteries upon abusive loading has significantly deferred the further application of LIBs. Herein, firstly, mechanical behaviors of the battery component materials are characterized by both in-situ and post-mortem experiments. Then, we reveal the formation process of various internal short circuit (ISC) modes inside batteries upon different abusive loadings with the aid of ex-situ observation using the X-ray Computed Tomography scanning technique and post-mortem characterization of the battery samples. To quantify the stress-driven ISC mode and failure behavior of the component material, numerical models for all component materials are established and applied in a cell model which can reveal the deformation-material failure-material contact-different ISC mode formation process. To further quantify the relationship between electrothermal response and mechanical response of battery, we develop a 2D detailed model with fully coupling of electrochemo-thermal-mechanics governing laws consisting of a 2D mechanical model, 2D ISC model, 2D heat model and Thermal Runaway model. The multiphysics model demonstrates a promising generalization in various SOC and loading situations. Results highlight the power of computational modeling to understand the underlying mechanism of safety issues in energy storage systems in a broader context.