Patent ID: 7038426

Claim:
A method for reconditioning a lithium ion battery having reduced capacity, comprising the steps of: providing a lithium ion battery from a lithium battery family, the battery including a negative electrode, a positive electrode, a nonconductive separator disposed between the negative electrode and the positive electrode, and a source of lithium and an electrolytic solution hermetically sealed in a container, and further including a negative terminal connected to the negative electrode and a positive terminal connected to the positive electrode extending through a face of the container to provide external connections; determining the voltage discharge profile for the lithium battery family to determine a characteristic voltage below a normal discharge voltage for which operation will result in a gradual loss of battery cell capacity leading to an inoperative cell, and selecting a voltage below the normal discharge voltage and above the characteristic voltage, wherein the selected voltage is sufficiently high so as not to damage a battery cell of the battery; slowly discharging the lithium ion battery to the selected voltage at a discharge rate sufficiently low to redistribute lithium ions in the negative electrode while substantially completely discharging the battery; providing a power source; connecting the power source to the negative terminal and the positive terminal of the battery; providing power to the battery from the power source to recharge the lithium ion battery so as to substantially uniformly redistribute the lithium ions in the positive electrode; wherein the capacity of the battery is substantially restored.