Effect of tab configuration on large-format battery performance based on three-dimensional electrochemical-thermal coupled model

Abstract Large-format prismatic lithium iron phosphate (LFP) batteries hold significant potential in energy storage systems. However, heat accumulates near the tabs when the LFP battery cell is operating, resulting in non-uniform temperature distribution within the cell. Optimizing the tab configuration is crucial for ensuring battery lifespan and preventing thermal runaway. Due to the complexity of the internal structure, existing research mainly focuses on the tab design of pouch cells, with limited studies on prismatic cells. In this work, a 3D electrochemical-3D thermal coupled model for 280 Ah prismatic LFP battery cell was developed and validated with experimental data. The effects of tab width and thicknesses on the thermal performance of the battery were investigated, and the optimal tab dimensions were determined. The results indicate that increasing the tab width from 3 cm to 7 cm significantly reduces the maximum temperature ( T max ) and temperature difference (Δ T max ) by 39.32% and 81.18%, respectively, with diminishing benefits at wider levels. Additionally, the regions of high current density are primarily concentrated near the positive tab. The augment of the tab thickness significantly enhances current uniformity and reduces Joule heating near the tabs, resulting in lower T max and Δ T max . However, the improvements diminish as thickness continues to increase. Furthermore, the optimized configuration, featuring a 7 cm tab width and tab thicknesses of 12 μm for negative and 16 μm for positive, achieved substantial reductions in T max and average temperature, along with a Δ T max of 4.1°C, effectively enhancing cell temperature uniformity compared to the original design. The proposed model and findings are expected to provide guidance for the design and optimization of large-format LFP batteries.