Lifetime Prediction Based on the Load Profile of Lithium Ion Batteries

Different operation conditions of lithium ion batteries like the temperature, the applied current and the state of charge of the electrodes determine the kinetics of the elementary reaction steps and therefore determine which reaction (reversible or irreversible) take place. The different reaction kinetics lead to different fatigue processes. During fatigue of lithium ion batteries material changes occur as well as changes in the cell balancing. Both have consequences for the redox reactions within the system and have to be considered for lifetime prediction. We investigated analytically kinetic laws of the reversible (charge and discharge processes) and irreversible (fatigue processes) reactions. With Kinetic Monte Carlo simulations the elementary steps were upscaled. Due to this it is possible to predict quantitatively the changes of the materials as well as changes in the cell balancing during operation of a battery. This provides information to design better materials for lithium ion batteries as well as it helps to select materials for each application specifically.