Predicting materials’ performance

Abstract

One of the most vital challenges in lithium-ion battery engineering and manufacturing is related to the accurate prediction of cell’s performance in various conditions (operating and storage temperature range, cycling rates, prolonged cycling, etc.). Macro-kinetic modeling of the processes occurring in the cell made tremendous progress during recent years. At the same time, substantial lack of data on intrinsic kinetic parameters, such as diffusion coefficients, exchange current, and their dependence upon lithium content in the solid materials restrains implementation of modeling. A practical approach to determining the proper form of the kinetic equations is presented in this chapter. This approach is based on interpretation of electrochemical measurements with respect to the structure of the electrode materials, and establishing the kinetic parameters, taking into account the connection between thermodynamic functions and kinetic parameters. The methodology refuses employing the concept of thermodynamic activity, but intensively uses empirical data of open circuit potentials (OCP) of the battery electrodes at varying degree of charge (DoC) measured at various temperatures. These data can also be useful for better understanding and prediction of most favorable voltage range for prolonged battery cycling life, and decrease the risk of catastrophic failures related to overtaxing the battery’s active materials. Several examples of practical accomplishments of this approach are included in this chapter.