Patent ID: 7576545

Claim:
A method for determining full capacity of a Li-ion battery comprising: depolarizing the battery until the battery is in a quiescent state; measuring a first open circuit voltage of the battery; determining a first state of charge value of the battery corresponding to the first open circuit voltage; partially charging the battery with a known state of charge by applying a constant current until the battery exhibits a measured second open circuit voltage of n*3.5 V, wherein n is equal to the number of cells of the battery; determining a second state of charge value of the battery corresponding to the second open circuit voltage measured after the step of partial charging; and correlating a charge energy with a change in the state of charge to determine a full capacity of the battery; wherein the charge energy is the energy required for charging at a constant current until the voltage across the battery reaches a predetermined value; and wherein the change in the state of the charge is the difference between the first state of charge value of the battery and the second state of charge value of the battery.