Lithium-Polymer batteries are of great interest to the automotive industry due to their higher power and energy density, higher cell voltage, longer cycle life and lower self-discharge compared to other battery chemistries. Electrochemical impedance spectroscopy is a powerful tool employed to investigate the fundamental electrochemical reactions within a Li-ion battery cell, which relates to state of charge, internal temperature and state of health .It should be pointed out that three crucial factors could affect the ability of a li-poly batteries to achieve fast charging techniques, including the acceptability of the active materials, cell design and charging profile. Hence, it becomes necessary to identify the effects of using different fast charging profiles on battery performance and quantify the battery degradation mechanisms due to using these profiles. The rate and shape of the charging current indubitably affect the charging time and the ageing rate of a battery. Depending on the application requirements, it is possible to use high-charging current in order to decrease the charging time. However, the influence of fast-charging current profiles should be investigated to identify their impact on battery functionality over time. The effect fast-charging current profiles on the cycle life of commercial li-poly batteries under different state of charge (SOC) ranges was studied using two methods:(1) Constant Current (CC) Charging, (2) Multistage Constant Current (MCC) Charging. Using these methods, respectively, the cell was charged to 4.2V followed by a constant voltage (CV) charging until the current declined to 0.05 C. batteries cycled under three cycling ranges (0%-60%, 20%-80% and 40%-100% SOC). the results revealed that protocol fast-charging MCC-CV(in 0%-60%, 20%-80% SOC) has a more important role in decreasing the degradation rate compared with protocol fast-charging CC-CV. The batteries cycled at (0%-60% ) perform far better than the other batteries in terms of retaining the capacity.
