The demand for lithium-ion batteries is increasing due to the on-going shift to a more sustainable society. One of the major reasons for the increasing demand is the increase in electrical vehicles. During the lifetime of a vehicle, the battery is cycled many times, which degrades the battery due to both mechanical and chemical factors. In this project we are interested in coupling the mechanical and electrochemical mechanisms of lithium-ion batteries in numerical simulations to increase our understanding of how this coupling affects the aging of lithium-ion batteries. Increasing our understanding of the aging phenomena will aid in battery design so that the aging mechanisms can be mitigated in better way. The main objective of this study is to elucidate how the micromechanical behaviour of the battery cell electrode influences the full cell-scale behaviour in terms of battery degradation. This includes understanding how the stiffness, porosity, and permeability changes because of state-of-charge (SoC) and mechanical load. To investigate this behaviour, we have developed a Multiphysics FEM model for COMSOL. This model incorporates solid mechanics, electrochemistry and fluid dynamics to accurately predict the homogenized behaviour of the battery electrodes. The geometry is based on CT-scanned microstructures of real battery electrodes. The results from the model will then be transferred and simplified models will be developed that can consider the complexity of the microscale without less computational cost. These simplified models will be used to aid battery design in an efficient way where different parameters can be varied and studied, without the need to run heavy microscale simulations.