The ProFeLi project, carried out from 1 February 2019 to 31 July 2022, aimed to bridge the gap between laboratory‑scale solid‑state batteries (SSBs) and industrial production. Solid‑state batteries that use a solid electrolyte and a lithium‑metal anode promise up to 70 % higher energy density than conventional lithium‑ion cells while eliminating the flammable liquid electrolyte that poses safety risks. Despite encouraging laboratory results, commercial availability remained limited because of a lack of scalable manufacturing knowledge and suitable production routes for the new cell components.
To address these challenges, ProFeLi focused on the entire value chain, from raw material handling to final cell packaging. The project developed robust handling procedures for lithium‑metal foil, including controlled atmosphere processes and laser‑cutting techniques that preserve foil integrity while enabling precise patterning. A key outcome was a production route for thin, pore‑free solid‑electrolyte separators that can be integrated into cathodes without relying on solvent‑based coatings, thereby improving packing density and reducing manufacturing complexity. The team also devised new manufacturing steps for embedding solid electrolytes into cathode layers, ensuring uniform contact and mechanical stability.
Cell assembly presented additional hurdles because the mechanical properties of lithium‑metal anodes and solid electrolytes differ markedly from those of conventional cells. ProFeLi introduced novel stacking concepts and packaging strategies that accommodate the higher reactivity and ductility of lithium while maintaining structural integrity. Functional demonstrators were built to validate the full cell architecture, including the new separator and cathode integration methods. These demonstrators confirmed that the proposed manufacturing steps could be scaled to pilot‑plant levels without compromising cell performance or safety.
The project’s scientific results also included detailed characterisation of the electrochemical behaviour of the new cell design. While the report does not provide specific capacity or cycle‑life figures for the pilot cells, the work demonstrates that the solid‑state architecture can achieve the targeted energy‑density gains and that the manufacturing process is compatible with existing industrial equipment. The safety assessment confirmed that the elimination of liquid electrolyte reduces the risk of thermal runaway, a critical requirement for automotive and stationary energy‑storage applications.
Collaboration was central to ProFeLi’s success. The core partners were the Technical University of Munich (TUM), represented by the School of Engineering and Design and the Department of Energy and Process Engineering, and the Institute for Machine Tools and Operations Science. The project was led by Professors Rüdiger Daub and Andreas Jossen. Initially, the German company Manz was responsible for coordinating the project and for several work packages, including the construction of functional demonstrators. When Manz withdrew at the project’s midpoint, TUM assumed full coordination and redistributed the remaining tasks among the remaining partners, including GS Glovebox, without incurring additional costs. The project was funded by the German Federal Ministry of Education and Research under the “Battery 2020” programme, part of the national “From Material to Innovation” framework, and was overseen by the project carrier Jülich.
The COVID‑19 pandemic caused experimental delays, leading to a six‑month extension of the project timeline. Despite these setbacks, ProFeLi delivered a comprehensive set of production technologies and process guidelines that bring solid‑state batteries with lithium‑metal anodes closer to commercial viability. The findings are expected to inform future industrial roll‑outs and to support the broader transition to safer, higher‑energy battery systems.