A linear time-invariant model for solid-phase diffusion in physics-based lithium ion cell models

► An LTI model, in the form of a state space model, is proposed for solid-phase diffusion in physics-based lithium ion cell models. ► The proposed model can be used for spherical and non-spherical particles. ► Impact of different particle shapes on electrochemical performances can be investigated. ► The model is much faster than solving the full model.