Pseudo-2D Aging Model for Energy Density, Lifetime, Fast-Charge, and Cost Tradeoffs in Li-Ion Batteries

Abstract

With continual technology advances, Li-ion batteries are poised to electrify diverse commercial applications ranging from data centers to heavy-duty vehicles to aircraft. Physics-based models are needed to optimize battery-design tradeoffs in energy density, fast charge capability, cost, and lifetime. This paper extends conventional pseudo-2D (P2D) Li-ion models by incorporating electro-chemo-thermo-mechanical aging mechanisms: 1) growth of solid-electrolyte interphase, 2) reversible and irreversible lithium plating, 3) pore closure and electrolyte displacement, and 4) particle fracture resulting in loss of active material. A parametric study is used to quantify overall degradation as well as underlying causes of cell failure across multiple electrode loadings with varying energy densities, operating conditions, and fast-charge protocols. Incorporating aging mechanisms necessitates challenging parameter estimation and model validation across diverse cell designs and cycling conditions. The P2D model is calibrated across three electrode loadings at beginning of life and one loading aged to 800 cycles using rate capability/voltage and differential capacity data. The calibrated model is then used to explore several life-extending techniques proposed in the literature including varying the charging temperature and adjusting the full-cell voltage windows. With continued validation, the proposed framework has potential to enhance the feedback loop between initial cell design, performance, and long-term resilience.