The aim of the GridBatt project is to work out the special requirements when using a battery storage system to ensure stable grid operation, in order to adapt the storage system to the requirements already during the design stage (selection of cell chemistry, technology, geometry, environmental conditions, etc.), to optimally dimension and design the storage system on this basis, and to optimize its operational management. Only a holistic view covering the cell chemistry, the interface to the system (usually the inverter), the system requirements and the respective feedbacks allow to exploit the full potential of storage technologies. A comparison of the special requirements, which typically demand high performance with small energy throughput and high fluctuation, with the existing currently economically viable storage technologies shows that there is a deficit of technical solutions here.
The aluminum-ion battery (AIB) approaches using aluminum and graphite as electrode materials are promising with energy densities in the range of 50-60 Wh/kg. Furthermore, a cycle stability of 500,000 cycles was achieved at a charge rate of 100C.
After categorizing the requirements of a battery storage system in the electrical grid (IESY), these are transformed into loads for the battery by a transfer function consisting of grid, power electronic actuator and controller (IESY and EST). Based on these requirements, different storage technologies for dynamic operation are investigated and characterized. The goal here is a standardized test specification for storage for grid stabilization, such as providing instantaneous reserve (EST). A more extensive gap analysis will demonstrate that aluminum-ion cells can close the existing gap (IISB). Consequently, aluminum-ion chemistry will be studied in more detail and verified for suitability to provide system services (IISB and EST).
After the suitability verification, the transfer of the preparation parameters to commercial cell systems and their fabrication will follow. The functional model of a pouch cell for use in storage systems for grid stabilization will be developed and tested in a functional demonstrator (IISB and EST).
In a final overall simulation, the behavior of a highly scaled aluminum-ion battery in the electrical grid is investigated for a specific application scenario and, in particular, the feedback effects from the grid to the battery and vice versa are evaluated. In particular, conclusions can be drawn from this regarding the material properties of the battery that need to be improved or the operating parameters of the converter that need to be adapted.