Cycle Life Study of Li-Ion Batteries With an Aging-Level-Based Charging Method

This study presents a preliminary investigation report on an aging-level-based (ALB) charging strategy that is possible to extend the battery lifespan by varying the charge current according to the state of health of a cell as opposed to the standard constant-current constant-voltage (CC-CV) and a four-stage constant current (4SCC) methods. Experimental tests have been carried out, which employed Sanyo UR14500P lithium-ion batteries in the cylindrical shape with a nominal voltage of 3.7 V and a rated capacity of 840 mAh. The results demonstrate that the ALB charging strategy with a CC charge profile is able to slow down the cell capacity fade by 3.84% compared with the standard CC charging method after 120 cycles, which increases the lifetime of 40 cycles to 50 cycles. Besides, the ALB charging strategy with a 4SCC charge profile is able to slow down the cell capacity fade by 2.55% compared with the standard 4SCC charging method after 100 cycles, which prolongs the lifetime of 30 cycles to 40 cycles. Nevertheless, the ALB charging strategy with both the CC and 4SCC charge profiles has much longer charging time than those with the standard charging method, and the charging time increases by 22.5% and 10.71%, respectively.