Abstract: A testing platform of single cell lifespan was set up, which is able to simulate the operating temperature and cycle life of battery. The lithium manganese LiMn₂O₄ 90 Ah battery used in pure electric bus was taken as the research objective to simulate the lifetime test under the operation condition at 10 ℃, 25 ℃ and 40 ℃, and to analyze the influences of temperature and operating range of State of Charge (SOC) on the battery cycle life. The results show that, Arrhenius equation can be used to analyze the effect of temperature on the battery impedance and capacity in different aging states. 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 lifespans under different accelerating stresses, an optimized control method is proposed, which can provide the basis for battery type selection and performance estimation in large scale application and prolonging the battery cycle life.

Key words: electrical engineering, lithium manganese battery, lifespan test, Arrhenius equation, accelerated stress, electrochemical impedance spectra