Lithium-ion batteries have become a key technology in our everyday lives, and great interest has grown during the past decade towards new materials and new configurations of the cells. Solid state lithium batteries (SSBs) allow having higher energy density without compromising power and capacity, while assuring high safety at variable temperatures and good cycle stability. However, during the charge and discharge of these batteries there are significant volume changes in the electrodes that produce stress and strain effects on the solid materials. These effects can make layers separate and cracks to form in the battery materials, which reduces the potentially improved performance of these batteries. The present study investigates the causes of the mechanical degradation and aging in Solid State Batteries using tool that allows to determine under which operation conditions a SSB can operate without suffering these undesirable effects. This tool consists on a physics-based FEM model of a complete thin-film battery that would simulate volume expansion of the positive electrode material during cycling of the batteries and predict local stress/strain failure as a function of the state of charge of the cell. The model follows a built-in approach in which the interface geometry increases in complexity gradually starting with a planar thin film, and it is validated experimentally at each step. Planar thin films (Li metal / LiPON / LMO) are constructed in collaboration with IMEC Research Center. Electrochemical characterization of these planar thin films is performed using the in-house developed Odd Random Phase Electrochemical Impedance Spectroscopy setup (ORP-EIS) in order to define the model input parameters. Further dilatation measurements are performed on the planar thin films in order to quantify volume changes in the cells during charge and discharge and validate the model results.
|Published - 7 Oct 2019
|12th International Conference on Advanced Lithium Batteries for Automobile Applications - Maritim Hotel Ulm Basteistraße 40 89073 Ulm, Ulm, Germany
Duration: 6 Oct 2019 → 9 Oct 2019
|12th International Conference on Advanced Lithium Batteries for Automobile Applications
|6/10/19 → 9/10/19