How to Simulate Battery Degradation

The tutorial “How to Simulate Battery Degradation” offers a practical insight into the simulation of mechanical degradation of battery electrodes using BatteryDict Degradation. Using a digital battery cell, it demonstrates how to investigate the volume changes in active materials caused by lithium intercalation and their effects on the microstructure. The starting point consists of previously generated bimodal anode and cathode structures, which are assembled into a complete digital battery cell.

The focus is on the workflow from defining the mechanical material properties through electrochemical charging simulation to the subsequent degradation simulation. Stresses, strains, and deformations within the electrodes are calculated and evaluated in three dimensions. Using a graphite anode as an example, the relationship between local lithium concentration and mechanical stress is also illustrated. The tutorial is intended for users who investigate electrochemical-mechanical interactions in battery microstructures and wish to better understand their influence on mechanical degradation.

• Fundamentals of electrochemical-mechanical battery simulation: Understanding the volume changes in active materials caused by lithium intercalation and their impact on the microstructure, mechanical stress, and degradation of battery electrodes.
• Design of a digital battery cell: Creation of a complete 3D battery structure consisting of bimodal anode and cathode structures, as well as a separator and current collectors.
• Materials and Mechanical Properties: Defining suitable materials and material constitutive laws for active materials, binders, separators, and current collectors, while accounting for elasticity and lithium-induced expansion.
• Charging and Degradation Simulation: Performing an electrochemical charging simulation and using the calculated lithium concentrations as the basis for the subsequent mechanical degradation simulation.
• Analysis of stresses and strains: Calculation and 3D visualization of deformations, von Mises stresses, and strains, as well as investigation of the relationship between local lithium concentration and mechanical loading.
• Practical application of the workflows in GeoDict with BatteryDict Degradation.