The Structur.E project, funded by the German Aerospace Center (DLR) under grant 03ETE018D, ran from 1 May 2019 to 30 April 2023 and focused on modelling and simulating cell degradation in lithium‑ion batteries. Its overarching goal was to resolve the trade‑off between driving range and fast‑charging capability by improving the rate performance of high‑energy anodes while reducing lithium‑plating‑induced degradation. The anode was chosen as the critical component for fast charging, and the project aimed to increase its high‑C‑rate capability and mitigate safety risks associated with metallic lithium deposition.
The technical work centred on developing physically based models for lithium‑plating and solid‑electrolyte‑interphase (SEI) growth, and integrating these into a comprehensive aging‑simulation framework. DLR’s modelling team produced detailed 3‑D microstructure‑resolved simulations that required high‑performance numerical methods. Microstructural data obtained from micro‑computed tomography (µCT) scans of silicon‑based composite electrodes were used to parameterise the models, ensuring that the simulations reflected realistic particle distributions, porosity, and tortuosity. The simulation framework was validated against experimental ageing data from the BEST‑Mikro/DLR cell‑testing platform, confirming its predictive capability for fast‑charging scenarios.
Key quantitative findings emerged from the simulations. High‑energy silicon‑composite anodes could deliver 1 800–2 200 Wh l⁻¹ at the electrode level under low‑C‑rate operation (≈ 0.1 C), but the energy density dropped to only about 35 % of this value when the cell was charged at 3 C, illustrating the severe impact of fast‑charging on capacity retention. The models also quantified the growth of the SEI layer and the extent of metallic lithium deposition over thousands of cycles, providing a mechanistic basis for designing safer, higher‑capacity cells.
In addition to modelling, the consortium explored advanced electrode manufacturing techniques. Laser structuring and mechanical grading were used to create electrodes with spatially varying silicon content, reducing local stress and suppressing lithium‑plating hotspots. These graded electrodes were fabricated into reference cells that served as testbeds for the ageing models. The project also produced a unified assessment matrix to evaluate candidate anode designs, a reference cell system, and a demonstrator that could be scaled for industrial use.
The Structur.E consortium included Forschungszentrum Jülich, the Helmholtz Institute Ulm, the Institute for Technical Materials Research (ITWM), the Fraunhofer Institute for Silicon Technology (ZSW), and the company M2M. DLR led the modelling and simulation effort, Jülich supplied experimental validation and post‑mortem analysis, ITWM provided µCT microstructure data, and M2M performed digital microstructure analysis. The collaboration built on earlier German Ministry of Education and Research (BMBF) programmes such as Multibat, LiECOSafe, and HighEnergy, where the same modelling approach had already proven successful.
By the end of the project, Structur.E had produced a validated simulation framework capable of predicting fast‑charging‑induced degradation, a set of manufacturing guidelines for graded, laser‑structured anodes, a reference cell system, and a demonstrator that could be transferred to industry. The short report summarises these achievements and outlines the next steps for scaling the technology to commercial battery production.