磷酸铁锂电池正极压实密度的多维度作用及对循环老化的影响OA

Electrode compaction is a key factor influencing the aging of lithium-ion batteries;therefore,investigating the effect of electrode compaction on battery aging is crucial to extending the service life of such batteries.Based on the traditional electrochemical models and aging mechanisms of lithium-ion batteries,an electrochemical aging model was established,and the mechanism by which different cathode compaction densities affect battery aging behavior was explored via a simulation system.Numerical simulation results show that,under the condition of maintaining a constant designed capacity for prismatic aluminum-shell batteries,increasing the cathode compaction density can raise the proportion of free internal space in the electrode,thereby significantly slowing down the overall battery aging rate.The study further reveals that within a certain range of compaction,the gas evolution effect exhibits a negative correlation with thermodynamic capacity loss,and the increase in compaction density can mitigate the negative impact of gas evolution on battery capacity.Quantitative analysis demonstrates that when the cathode compaction density is 2.40 g/cm3,the cell achieves a capacity retention rate of 80％after 5 491 cycles.When the cathode compaction density is increased to 2.60 g/cm3,the cell still maintains a capacity retention rate of over 85％after 5 491 cycles.This research elucidates that a higher cathode compaction density can alleviate battery aging within a specific range,and this conclusion provides a theoretical basis for optimizing electrode structural parameters and inhibiting battery aging.