Eight German industrial and scientific units have come together to pursue two key innovations in lithium-ion battery technology: the replacement of metal foils with a metallized fabric structure and the use of silicon as anode material.
One part of the project focuses on new electrodes with lightweight fabric-based current collectors for LiBs using resource-saving technology. This technology requires less use of primary raw materials such as copper and aluminum while allowing for higher energy density, which means additional material savings from the cell to the system level. Another area of development focuses on the use of pure silicon as anode material together with the light fabric structure of the electrodes.
The project is funded by the German Federal Ministry for Economic Affairs and Climate, and the work is divided into corresponding sub-projects that will be implemented by the individual partners over the next three years.
Porcher Industries Germany GmbH develops ultra-light glass fabrics as the basis for electricity collectors. At the same time, Dresden University of Technology, Institute of Textile Machinery and High Performance Material Technology (ITM) is developing ultralight carbon fabrics based on carbon spreading technology.
In the next step, elfolion GmbH metallizes the developed carbon and glass fabrics with vacuum processes for use as current collectors. elfolion focuses on the development of the cathode, which consists of porous fractal structures, which are the active component of the electrode. The open mesh and light structure of the fabrics and the porous coating significantly reduce material usage and larger active surfaces, which in turn significantly increases the energy density of the battery cells in terms of both mass and volume.
RWTH Aachen University, Chair of E-Mobility Components (PEM) Production Technology, is developing processes for coating fabric-based current collectors with slurry-based electrode materials. In addition, it investigates the design and production of battery cells based on components supplied by project partners.
Fraunhofer FEP’s goal in the revoLect project is to develop a process for layering silicon on fabric structures.
“We have to match the silicon layer and the fabric structures together in such a way as to achieve the optimum in terms of the gravimetric energy density of the anode,” said Fraunhofer FEP researcher Claus Luber.
One of the research partners, Customcells, coats the new substrates with electrode paste under industry standard conditions. The performance of the batteries is then tested with electrochemical measurements.
The Institute of Experimental Physics of the Freiberg University of Technology is involved in the characterization of the treated individual components as well as the button and pouch cells. From this, microstructure-property correlations as well as design proposals and processing parameters are derived for the partners.
Romonta GmbH connects the manufactured cells to the battery systems and performs the final practical application tests. In the evaluation, cell parameters such as aging and current/voltage resistance must be analyzed and transferred to the mobile application. This is expected to ensure efficient performance of LiB.