Over-discharging is easier to occur at low temperatures. In this paper, the degradation characteristics were investigated by discharging to 2.75-0 V at 0°C and discharging at constant voltage for 0 and 2 hours, respectively. The results show that capacity fades linearly except for the 0 V-2 h cell that fades at an accelerated rate. The fade rates increase with decreasing discharging voltage. Besides, both the longer time of constant voltage and the lower discharging voltage contribute to loss of lithium inventory, loss of active materials, and internal resistance increase.
Keywords Lithium-ion battery, over-discharge, low temperature, degradation