Research on the temperature radius stratification model based on electrochemical-thermal-force coupling in Lithium-ion batteries

This study investigates aging mechanisms in lithium-ion batteries (LIBs) under high rate conditions using an electrochemical-thermal-mechanical (ETM) coupling model with temperature-radius stratification. Focusing on solid electrolyte interface (SEI) formation, thermal dynamics, and diffusion-induced stress (DIS), we reveal that increasing C-rates significantly elevate heat generation, reducing electrode thermal stability and accelerating positive electrode degradation. High-rate cycling intensifies SEI uneven distribution and concentration, hastening capacity loss. Prolonged cycling shows greater von Mises stress in positive electrodes (tensile deformation) versus negative electrodes (compressive deformation), with lower available lithium-ion concentration in positives. Cut-off voltage analysis demonstrates that reducing charging voltage or increasing discharging voltage mitigates capacity loss, with positive electrodes more sensitive to discharge voltage and negatives to charge voltage. Our temperature-radius stratified model provides precise analysis of fast-charging aging mechanisms, offering theoretical support for optimized battery design and operation strategies. Future work should address SEI film dynamics, lithium plating, and internal gas generation for comprehensive aging understanding. • Developed a novel temperature-radius stratified electrochemical-thermal-mechanical coupling model for precise analysis of aging in lithium-ion batteries under high-rate conditions. • Revealed that higher C-rates exacerbate SEI non-uniformity and accelerate capacity fade. • Demonstrated cathode-dominated mechanical degradation with severe tensile stress under prolonged cycling. • Proved that adjusting cut-off voltages effectively mitigates capacity loss, with cathode/anode showing distinct voltage sensitivities. • Validated model superiority over conventional methods, providing theoretical support for optimized battery design and charging strategies.

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