Microstructure-resolved degradation simulation of lithium-ion batteries in space applications

In-orbit satellite REIMEI, developed by the Japan Aerospace Exploration Agency, has been relying on off-the-shelf Li-ion batteries since its launch in 2005. The performance and durability of Li-ion batteries is impacted by various degradation mechanisms, one of which is the growth of the solid-electrolyte interphase (SEI). In this article, we analyse the REIMEI battery and parameterize a full-cell model with electrochemical cycling data, computer tomography images, and capacity fading experiments using image processing and surrogate optimi-zation. We integrate a recent model for SEI growth into a full-cell model and simulate the degradation of bat-teries during cycling. To validate our model, we use experimental and in-flight data of the satellite batteries. Our combination of SEI growth model and microstructure-resolved 3D simulation shows, for the first time, experi-mentally observed inhomogeneities in the SEI thickness throughout the negative electrode for the degraded cells.