A Microstructural Resolved Model for the Stress Analysis of Lithium-Ion Batteries

The stress field in a lithium-ion (Li-ion) battery can have a significant impact on its performance. To better understand the stress distribution in a Li-ion battery cell, a 2D multiphysics microstructural resolved model (MRM) with realistic electrode geometries has been developed. This model considers the species transport, battery kinetics, and the deformations and stresses of the components caused by Li intercalation. The model was used to examine a LixC6|PP|LiyMn2O4 cell. The stress distributions and developments in the active particles and in the binder were discussed in detail. The results show that while the intercalation stress distributions in general agree with the description of the analytical solutions for spherical active particles, a higher tangential stress can arise at the particle surface at locations where the local curvature is concave or when the particle is next to a rigid current collector. The results also indicate that between the two binder systems investigated, the one with a lower modulus and larger elongation appears to be a better choice over the higher modulus, less ductile grade, provided that the two systems have the same ratio of the interfacial adhesion strength to the binder strength. This work demonstrates the potential of the MRM in improving our understanding on the stress and deformation in battery components and in the selection of battery materials.