A fast-charging pattern search for li-ion batteries with fuzzy-logic-based Taguchi method

This paper proposes a fuzzy-based Taguchi method (FBTM) to experimentally search an optimal fast-charge pattern of Li-ion batteries for maximizing the charging cost-effectiveness. The pattern of the adopted multistage constant current charging method is obtained through the consecutive orthogonal array (OA) experiments via systematically tuning the C rate of the multistage charging currents. The fuzzy logic is applied to convert the signal-to-noise (S/N) ratios of dominant quality characteristics, derived from the Taguchi method (TM), into a single fuzzy dual-response performance index (FDRPI) to maximize the charging cost-benefit function. The predicted best pattern is verified by conducting the confirmation tests. The confirmative examinations show that the obtained pattern is capable of charging the batteries to over 91% available capacity within 42 minutes. Comparing with the conventional constant current-constant voltage (CC-CV) method, the devised scheme has the performance enhancements of more than 81% charging time reduction, 30% more life cycles, and over 0.5% charging efficiency increase.