Study on cell temperature rise characteristics and thermal effect analysis of battery packs for PEV

摘要

This paper studies the temperature rise, internal resistance and open-circuit-voltage (OCV) characteristics of 45Ah lithium iron phosphate cell at different charge-discharge rates, to guarantee the good thermal stability of power battery packs in pure electric vehicles (PEVs) under high-power output conditions. A thermal model of lithium-ion cell is established based on the heat transfer theory. Charge-discharge tests and numerical simulations on cell's thermal performance are performed. The proposed model is proved to be accurate by analyzing the results of simulations and experiments. Based on the cell model, a simulation model of battery pack is built in the software of Matlab/Simulink, and simulations under various working conditions are carried out, then dynamic performance and heat generation characteristics of the battery pack are obtained. Numerical simulation on thermal effect of battery pack is performed, and optimizations on structure are presented. Results indicate that both the heat dissipation ability and temperature field uniformity are improved obviously, which satisfies the application requirements in PEVs.