Patent ID: 8188715
Filing Date: 2012-05-29
Classification: H01M,Y02E

Abstract:
1. A method of determining extent and type of capacity fade of an electrochemical cell comprising: identifying a first volume fraction of a first active material in a first electrode at a first time; discharging the electrochemical cell from the first time to a second time; identifying a first capacity of the first electrode at the second time; identifying a second volume fraction of the first active material using a first dimensionless factor (θ), the first dimensionless factor (θ) having a difference between an aged capacity of the electrochemical cell and the first capacity as a numerator and a change in capacity of the first electrode to the first capacity as a divisor; identifying a first amount of the first active material lost from the first electrode from the first time to the second time based upon the first volume fraction and the second volume fraction; identifying a third volume fraction of a second active material in a second electrode at about the first time; identifying a second capacity of the second electrode at about the second time; identifying a fourth volume fraction of the second active material based upon the second capacity; and identifying a second amount of the second active material lost from the second electrode from about the first time to about the second time based upon the third volume fraction and the fourth volume fraction.