Study of Polarization-Induced Strain Distribution and Mechanical Damage in Lithium-Ion Batteries

Strain is one of the main reasons for the LIB performance degradation, and it has become a research hotspot as the battery energy and power density increase. In the study, battery polarization is investigated using strain gauges. The battery temperature and distance between the jelly roll and steel case are determined to ensure the accuracy of the measurements. Polarization-induced strain is distributed along the axial direction, while it responds faster than temperature and slower than voltage. Through multiphysics simulation, it can be found that the collector potential difference is greater than the electrode, and the cathode collector potential difference is greater than the anode collector. The polarization ultimately leads to an uneven total elastic strain energy density distribution in the direction of length and depth. Energy-type batteries have higher elastic strain energy than power-type batteries due to greater polarization, and the elastic strain energy provides the driving force for particle rupture, leading to more particle fragmentation and separation. Preliminary results indicate that strain sensitivity and response speed outperform the temperature sensitivity. This complex coupling of lithium diffusion from macroscopic polarization to the atomic scale down to the particle level ultimately manifests as macroscopic performance differences between the two types of battery. Therefore, synergistically mitigating mechanical and electrochemical degradation through strain management emerges as a core strategy for enhancing the durability of energy storage batteries.