A Simplified Methodology to Quickly Build a Degradation Prediction Model for Lithium-Ion Batteries

Abstract:
In this paper, a new simplified modeling methodology based on empirical research results for the capacity degradation of lithium-ion batteries is presented, which produces first simulation results within few days and using one cell aging test. Conventional methods need several months to parameterize a suitable model. Based on that, a calendar and cycle aging model considers graphite as the anode material is implemented in MATLAB® and Simulink® environment. For model parameterization, datasheet and pseudo-OCV curve of the considered cell as well as a short-term aging test are needed. The simulation model requires as input parameters current, voltage, and temperature over time. The validation of the developed model is based on a test data of an 18650 lithium-ion cell. In the performed simulations, a coefficient of determination R² from 0.88 to 0.991 could be achieved in the investigated test. Based on these results, statements for capacity degradation and lifetime expectations can be given.