Experimental and numerical insights into quantifying temperature and heterogeneity impacts on lithium-ion battery performance: From cell to pack

Lithium-ion battery performance and degradation are critically constrained by temperature fluctuations and cell-to-cell heterogeneity during operation. This study employs coupled experiments and simulations to dissect the joint impacts of temperature, dynamic cycles, and inconsistency across scales, from single cell to pack. Cell-level testing across sub-zero temperatures reveals extreme thermal sensitivity: certain chemistries exhibit rapid capacity fade and impedance surge below −15 °C, while others show markedly lower degradation; achievable capacity significantly declines under extreme cold. Electrochemical-thermal modeling attributes these losses primarily to polarization and mass transfer limitations governed by sluggish kinetics and material parameter spread. Analysis of dynamic profiles demonstrates that charge/discharge variations can mitigate aging compared to sustained high-power discharge, with targeted pulse management offering efficiency benefits. Pack-level simulations of evolving inconsistencies identify temperature inhomogeneity as the dominant driver of performance decay, substantially exceeding the impact of aging parameter dispersion alone. Pre-assembly capacity screening fails to prevent divergence induced by inconsistent aging rates. Further, state-of-charge (SOC) homogeneity targeting paradoxically accelerates divergence in remaining available capacity. Crucially, mitigation strategies include leveraging low-temperature-tuned electrode chemistries to curb cold-climate fade, enforcing strict thermal-path uniformity at the pack level to counter accelerated ageing dispersion from thermal-parameter mismatch, and implementing residual available energy management instead of SOC-only balancing to break the self-reinforcing capacity drain loop. These integrated insights enable tighter electrochemical control, refined thermal architectures, and improved uniformity strategies for lifecycle efficiency management.