This chapter addresses the modeling of shipboard lithium-ion battery (LiB) energy storage systems tailored to the extreme marine environments, which are characterized by shipboard swaying, high humidity/salt spray, and temperature fluctuations—factors that induce distinct LiB degradation behaviors relative to terrestrial scenarios. A lab-scale marine environment test platform was constructed in compliance with the China Classification Society’s type approval standards, where macroscopic and microscopic cyclic aging tests were conducted on NCR 18650GA LiBs to capture capacity decay, impedance evolution, and electrode microstructural changes. A swaying-coupled LiB model was proposed, incorporating particle-level degradation mechanisms (SEI layer growth, lithium plating, and active particle cracking) and a physics-informed data-driven aging model (PIBM). This PIBM integrates electrochemical physical constraints with a neural network; compared with conventional hybrid models, it achieves a 25.48% reduction in computational time and a maximum 28.3% decrease in state-of-health (SOH) estimation error, with robust generalization performance under static conditions. Additionally, a temperature-coupled electrochemistry-thermal model was further developed, which identifies 45  \(^{\circ} \) C as the optimal operating temperature for the tested LiBs and quantifies the synergistic degradation effects of extreme temperatures, overload operation, and high depth of discharge (DoD). The established environment-adaptive LiB models accurately characterize the coupled electrochemical-mechanical-thermal degradation mechanisms of shipboard LiBs, providing a theoretical and experimental foundation for the dynamic management of marine battery energy storage systems, while also highlighting the need for lightweight models to enable real-time onboard applications.