Modeling analysis and optimization of performance decline and lifespan decay of ternary lithium-ion pouch cell at low temperature

Lithium-ion batteries (LIBs) experience significant performance degradation in low-temperature environments, resulting in reduced capacity retention and shortened lifespan. To address this issue, an electrochemical-thermalaging coupled model was developed and validated with experimental data, providing a comprehensive analysis of the material properties and kinetic characteristics affecting battery performance at low temperatures. The research investigates the impact of seven key factors on battery capacity and aging at low-temperature, including the properties of electrolyte and anode materials. The simulation results indicate that improving internal polarization and reducing ohmic impedance can substantially improve both capacity and lifespan. Notably, doubling the electrolyte conductivity increases battery capacity by 12.63 %, while the capacity retention rate remains stable. This improvement is attributed to reduced ohmic impedance, which expands the state of charge (SOC) window during operation. However, at high anode SOC, lithium-ion diffusion becomes restricted, promoting lithium deposition and causing a reduction in capacity, thereby explaining the unchanged capacity retention rate. Additionally, optimizing anode property parameters mitigates solid-phase diffusion polarization, extending lifespan by over 13.49 % and increasing discharge capacity by over 14.86 %. This study highlights the critical role of material optimization in enhancing LIB performance under low-temperature conditions.