The performance of lithium-ion pouch cells is significantly affected by external mechanical loads in addition to electrochemical operating conditions. This study presents a simplified electrochemical-mechanical model to analyze the influence of compressive forces on a 19.6 Ah lithium-ion pouch cell. External loads are translated into strain using a stiffness-based formulation, which is further linked to porosity variation, capacity fade, and internal resistance rise. A voltage model incorporating open-circuit voltage and ohmic drops is used to simulate discharge characteristics under different charge/discharge rates (0.25C, 0.5C, and 1C) and mechanical loads (0–8 kg). Simulation results indicate that increasing load leads to reduced capacity and elevated resistance, with the effect becoming more pronounced at higher C-rates. Quasi-open circuit voltage (Quasi-OCV) comparisons further reveal measurable shifts in voltage–SOC profiles before and after loading. The proposed framework provides a computationally efficient and adaptable tool for exploring electrochemical–mechanical interactions, offering valuable insights for battery design, safety, and performance optimization.