Evaluation of Rapid Charge Methodologies for Li-Ion Chemistry

Rapid charge comparison of pulse charge to conventional CC-CV charge was performed in this study using a three electrode Li-ion cell of 300 mAhr capacity and 18650 Li-ion cells of 2 Ahr initial capacity. Pulse current and pulse voltage charge up to 4.1 V were ineffective as a rapid charge technique. Beyond 4.1 V charge, 80% capacity gain was achieved with at T = 20oC. Lower temperature of 0oC results in 3 times capacity gain over CC-CV charge after 15 minutes. Cell polarization potential reached as high as 5.5V at 2.5C-rate, with anode potential as low as -0.6V vs Li reference electrode. Subsequent discharge indicated no lithium plating. Computed cell internal resistances and individual anode and cathode resistances during pulse charge suggest that charge rate capabilities are limited by the anode kinetics.