Laser drying of electrode coating in lithium-ion batteries: IDEEL research project aims to scale up the process to industrial production speeds for the very first time

The research project “IDEEL” is funded as part of the BMBF program Batterie2020 by the Federal Ministry of Education and Research (BMBF) under the funding code 03XP0414A through the project management organisation Project Management Jülich (Forschungszentrum Jülich GmbH). The project partners are Laserline GmbH, Coatema Coating Machinery GmbH and Optris GmbH, as well as the Fraunhofer Institute for Laser Technology (ILT), the Fraunhofer Research Institution for Battery Cell Production (FFB), the Münster Electrochemical Energy Technology (MEET) Battery Research Center at the University of Münster and the Production Engineering of E-Mobility Components (PEM) at RWTH Aachen University. The aim of the three-year project is to develop an industry-relevant laser drying process that will enable series production of lithium-ion batteries that is both more climate-friendly and economical.

Initially, a new electrode paste optimized for laser use will be developed as a coating material (PEM, MEET), a highly efficient laser system with a large-area, homogeneous spot (Laserline) and a highly integrative thermographic camera for contactless process monitoring (Optris, Laserline, Fraunhofer ILT). Based on these contributions, the laser-based drying process will be scaled up to industry-typical feed rates within a demonstrator (Coatema) and the physics-based model of the new drying process subsequently validated (ILT, FFB).

The research results are to be incorporated into the FFB’s processes in the future. The work of the FFB is considered one of the flagship projects of German battery research and is expected to become the principle development center of modern battery cell production for both Germany and European partners, with the goal of reducing German and European manufacturing dependence on the world market. A complete production infrastructure is therefore currently being built at the Münster site, with the intention of providing support to companies and research institutions seeking to test and optimize the series production of new battery designs.

The drying process addressed by the IDEEL project is part of the electrode manufacturing process for high-power battery cells, such as those used in electric vehicles and home storage systems. It is used to dry an electrode paste (slurry), which consists of a specially adjusted, homogeneous active material mixture and is applied to the copper foil of the battery electrode. Up to now, convection dryers have been used to dry this electrode coating, but the thermal energy transfer is only indirect into the material and thus places a heavy burden on both the CO2 balance and the energy costs of battery production. The IDEEL project partners are therefore focusing on up-scaling a more energy-efficient drying process in which the coating is irradiated using high-power diode lasers. The process benefits from the strong absorption of infrared laser light in the coating material, allows for more flexible and precise process control compared to common convection technology, and where the IDEEL project ultimately aims to demonstrate web speeds of up to 30 meters per minute. The compact design and efficient energy transfer are expected to significantly ease the extensive space requirements of the drying sections, which are typically more than 100 meters long – with a significantly reduced spatial footprint for the production environment, the planning of new production systems should enable faster and more energy-efficient process control.