Forecasting capacity degradation of lithium metal batteries using a data-driven approach

Conventionally, experiments that measure battery lifespan and SOH are adopted to evaluate performance, thereby assisting the development and evolution of novel battery systems. This kind of process, however, normally requires a long evaluation cycle, which inevitably hinders battery developers and users from efficient production, use, and optimization. On the other hand, informatics and have brought new opportunities to battery prognosis. These data-driven or machine-learning-based methods exhibit the great potential to unveil hidden information from the battery degradation data of early cycles and generate forecasts on future performance.

So far, most data-driven approaches for battery prognosis are focused on predicting the performance of commercial lithium ion batteries, which usually require large dataset consisting of high quality data. When exploring novel battery systems such as , however, these kinds of methods are less suitable as the dataset size as well as the data quality is rather limited. It is therefore extremely important to develop a generalizable battery prognosis method that is compatible with small datasets and can endure compromised quality data.

(a) The architecture of a LMB, consisting of a layered oxide cathode, e.g. LiNi0.5Co0.2M0.3O2 (NCM) or LiCoO2 (LCO), a lithium metal anode, and organic liquid electrolyte. The comparison of two NCM-based LMBs in terms of (b) cycling performance and (c) the discharge voltage curves. Credit: Science China Press

(a) Voltage curve-related features are extracted through STL decomposition. (b) Features are extrapolated to future cycles using its historical information. (c) Features are correlated with capacity decay through regression models. (d) The final estimation of capacity degradation trajectory. Credit: Science China Press

(a) The cycling performance of all batteries used in this work. (b) The forecasted and the actual capacity degradation trajectory of the example battery. (c) Parity plots between the actual and predicted end of life. The benchmark method as previously suggested by Severson et al. (Nat. Energy 2019, 4, 383) was adopted for comparison. (d) Histograms of MAEs and median errors of end of life predictions. Credit: Science China Press