Patent ID: 8373419
Filing Date: 2013-02-12
Classification: G01R,H01M,Y02E

Abstract:
1. A method of estimating a lifetime of a rechargeable lithium battery, the rechargeable lithium battery comprising: a positive electrode having a positive active material capable of absorbing and releasing lithium ions; a negative electrode having a negative active material containing at least one of silicon and tin; and an electrolyte having lithium-ion conductivity and disposed between the positive electrode and the negative electrode, the method comprising: A) detecting an open circuit voltage of the discharged rechargeable lithium battery at least two times while the rechargeable lithium battery undergoes charge/discharge cycles; B) on a two-dimensional graph defined by the open circuit voltage and the charge/discharge cycle, plotting the detected at least two voltage values as a function of ordinal numbers of charge/discharge cycles at which the at least two voltage values are detected; C) drawing a circular arc on the graph such that the circular arc passes through the plotted at least two voltage values; and D) estimating the lifetime of the rechargeable lithium battery on the graph based on an ordinal number of a charge/discharge cycle at which the drawn circular arc is expected to come close to the open circuit voltage equal to or lower than a discharge end voltage.