Modeling and experimental analysis of the thermal and electrochemical characteristics of lithium-ion cells with different electrode thickness

The transportation characteristics of Li+ in the active materials significantly affect the life and overall performance of lithium-ion cells. Analyzing the relationship between electrode thickness and heat/mass-related characteristics is thus very important for lithium-ion cells. The objective of this study was to investigate the effect of electrode thickness on the cell performance by developing a precise one-dimensional electrochemical–thermal coupled model with experimental validation. The thermal and heat-generation characteristics were investigated firstly. Then, the effects of the electrode thickness on the short-term and long-term electrochemical performance of lithium-ion cells were also explored experimentally and numerically from the perspectives of Li+ transport characteristics and discharging behaviors. The results indicated that the electrode thickness had a significant influence on the cell performance. Firstly, the cell with a thicker electrode showed a lower voltage plateau and an earlier stopping of the discharging process compared with the cell with a thinner electrode during a single discharging test; meanwhile, the cell with a thicker electrode presented a faster capacity degradation rate in the long-term cyclic tests. These influences were explained through the Li+ transportation mechanism and the electrochemical–thermal coupled effect.