Abstract: The cycle life of lithium battery is restricted by various factors. A testing platform of single cell lifespan was set up, which is able to simulate the operating temperature and cycle life of the battery. This paper takes the lithium manganese (LiMn2O4, 90Ah) battery used in pure electric bus as the research objective for simulating lifetime test under the operation condition at 10, 25 and 40 degree, and analyzing the influence of different temperatures, rates and usage state of charge(SOC) range on battery cycle life. The result shows that: arrhenius equation can be utilized to analyze the temperature factor on impedance and capacity during battery ageing. The third order RC equivalent circuit and electrochemical impedance spectra are helpful to get the polarization states under different SOC ranges and analyze the mechanism of battery capacity retention. By comparing the different accelerated stress results of lifespan test, an optimized control method is proposed which provides basis for estimation of battery type and performance in large scale application and prolonging the battery cycle life.

Key words: Lithium manganese battery, Lifespan test, Arrhenius equation, Accelerated stress, Electrochemical impedance spectra