In Situ Monitoring of Lithium-ion Battery Degradation Using An Electrochemical Model

Abstract

Lithium-ion batteries (LIBs) are increasingly popular for electric vehicle and grid storage applications but degradation mechanisms remain poorly understood and are difficult to characterize accurately. Here a new method for in situ monitoring of internal degradation in LIBs using an electrochemical model (ECM) is introduced. The main contributions of this work can be summarized as follows: (1) An ECM is developed based on a single particle model, the parameters of which are reorganized from the original physical property parameters for convenience of identification, with each new parameter assigned a specific physical meaning. (2)Identification methods for all parameters aredetermined through activation-and-response analysis,and a combined load profile for parameter identificationis developed. (3) Cyclic aging experiments are carriedout and the aforementioned model and parameteridentification methods are applied at appropriateintervals. The predicted trends of 7 of the 9 modelparameters show a strong correlation with theexperimentally observed degradation.