A pseudo three-dimensional electrochemical–thermal model of a prismatic LiFePO4 battery during discharge process. (1st February 2015) - Xu, Meng
Abstract: A lithium ion battery consists of numerous electrochemical cell units. Thermal and electrical behaviors of these local cell units have great influence on the battery's performance and safety. To study the relationship between the cell units and the battery cell, a pseudo 3D (three-dimensional) model was developed for a prismatic LiFePO4 battery by coupling the mass, charge, and energy conservations, as well as the cell electrochemical kinetics. The model treated the battery with current collecting tabs as 3D and the local cell units as 1D. Both electrochemical and thermal characteristics of the battery were studied by using this simplified model during the discharge process. A uniformity index characterizing the SOC (state of charge) distributions among 1D cell units was also introduced. This index was used to investigate the effects of the tab placement on the uniformity of the battery cell. The placement of the positive and negative current collecting tabs on the prismatic battery was found to have a significant effect on the distributions of its potential and local reaction rates, which therefore affect the heat generation rate, and thus the temperature distribution within the battery. Highlights: We develop a 3D electrochemical–thermal model for a prismatic LiFePO4 battery. Reaction rate distribution is not in a uniform mode due to electrical gradient. The higher reaction rate, the more quickly the heat generated in local regions. The temperature is higher in the region close to the tabs than other regions. Tabs placed on opposite sides will improve the uniformity of thermal distribution.