Server

Brief description

The planned “Server” research project aims to optimize cell finalization through an innovative system design on the one hand, and through innovative process adjustments aimed at reducing process costs and energy consumption on the other. Furthermore, the adapted forming process is intended to improve the resulting energy efficiency and service life of the battery cells, thereby enhancing the sustainability of the produced battery cells throughout their entire life cycle. As an innovative plant concept, the serial connection of battery cells during formation is to be developed. This allows multiple cells to be charged simultaneously, rather than individually as has been the norm to date. This method promises significant cost reductions and increased energy efficiency through fewer power electronics, power lines, and conversion losses. However, there are technical challenges, such as ensuring uniform state of charge and establishing electrical connections between the series-connected battery cells, which this project aims to address. As part of the project, a demonstrator for this innovative system concept for cell finalization is to be built at the Fraunhofer Institute for Battery Cell Research and Production (FFB) in Münster to demonstrate the feasibility and superiority of this system concept. A Technology Readiness Level of 6 to 7 is targeted.

As an innovative process adaptation, the cell finalization process (in particular formation and quality testing) is to be optimized in order to reduce process time and energy consumption on the one hand, and to improve cell quality in terms of energy efficiency and longevity on the other. This is to be achieved using model-based methods. To this end, simulations and predictions based on artificial intelligence are carried out for process optimization. This is coupled with innovative measurement techniques such as rapid electrochemical impedance spectroscopy (rapidEIS). The model-based simulation of the formation process enables a targeted improvement in the Solid Electrolyte Interface (SEI) quality. Through mathematical optimizations in the simulation environment, the SEI layer thickness can be minimized, for example, to achieve better energy efficiency and longevity of the battery cell. rapidEIS enables a rapid and detailed quality assessment of the formed battery cells. This allows conventional, time-consuming, and energy-intensive testing procedures for determining cell quality to be replaced, saving both process time and energy. Overall, the project makes an important contribution to increasing energy efficiency and sustainability in battery cell manufacturing. Additionally, production costs can be reduced.

The entire project is divided into a total of five work packages:

WP1 Project Management and Coordination: WP1 involves the active coordination of collaboration among the project partners by the project coordinator. This includes organizing the project structure and steering project activities. Continuous project monitoring ensures that deadlines and milestones are met. In addition, the project coordinator is responsible for organizing reporting and publication planning.

WP2 Battery Cell Manufacturing and Testing: This work package involves the manufacturing and testing of battery cells. To this end, large-format pouch cells are manufactured at Fraunhofer FFB on an industrial scale. In addition, small-format cells in a 3-electrode configuration are manufactured and tested, which are necessary for model parameterization for process optimization (WP4). At the outset, the reference process for cell finalization is established as a benchmark for the project. To this end, measurements are conducted to determine the actual energy requirements. Furthermore, material procurement and production planning take place within this WP. The manufactured battery cells are then tested for performance and service life using various test procedures.

WP3 Development of the serial connection for cell finalization: At the start of the project, market, literature, and patent searches regarding the serial connection of battery cells will be conducted, and the requirements for a demonstrator at Fraunhofer FFB will be defined. Building on this, concepts for cell finalization, charging and measurement technology, as well as a specification sheet, will be developed, with the partners FFT, INGUN, and Safion involved. A forming tray for 6–10 cells with adjustable pressure, active thermal management, and a balancing system for automated state-of-charge adjustment will be developed, and the associated hardware will be implemented. To ensure low-loss current delivery and precise voltage and temperature monitoring, novel contact solutions and sensor technology will be developed and integrated into the demonstrator system. In parallel, the rapidEIS measurement technology will be optimized for signal excitation, single-cell voltage measurement, and system integration to ensure efficient and interference-free monitoring of the series-connected cells.

AP4 Optimization of the cell finalization process: At the start of the project, research will be conducted on modeling and measurement methods for the finalization of battery cells to reduce process time and energy consumption and improve cell quality. This involves the use of physicochemical, electrothermal, and AI-based models, which are parameterized, trained, and used for simulation studies to optimize SEI quality, longevity, and energy efficiency. Based on rapidEIS data, critical process parameters are identified, KPIs are derived, and automated evaluation algorithms as well as software tools for visualization, monitoring, and dynamic feedback are developed. Various optimization approaches are first tested on test cells using reference electrodes and then transferred to large-format pouch cells to implement practical improvements in the formation process.

WP5 Demonstration and Validation: In this work package, the demonstrator for serial interconnection in cell finalization will be constructed at Fraunhofer FFB and integrated into the existing production line. After adapting the test chamber and integrating the previously developed components, functionality will be verified and the system commissioned.

Subsequently, the optimization approaches from WP 4 will be transferred to the demonstrator, process adjustments resulting from serial interconnection will be investigated, energy consumption will be measured, and potential savings as well as improvements in cell quality will be validated. Finally, a techno-economic-ecological assessment (TÖÖB) will be conducted, including technology screening, cost analysis, and life-cycle assessment.