Battery Life Estimation Model and Analysis for Electronic Buses with Auxiliary Energy Storage Systems

Battery range and life are two critical performance parameters for managing the operating life of electric buses. While battery range can be estimated, battery life estimation is complex. Additionally, physical battery lifetime testing is both costly and time prohibitive. This is due to the random nature of both transient and peak current loads that the electric buses experience in typical urban operations. A methodology for predicting battery life in electric buses that utilize supercapacitor modules in the auxiliary energy storage system will provide a valuable way to compare various energy storage systems with different converter topologies. The model is validated with field data from electric buses with a 400V lithium-ion battery configuration. The effectiveness of the model is demonstrated by predicting the battery life for a 530V Lithium-ion battery configuration with a supercapacitor module as an auxiliary energy storage system.