IDEEL project: Industry-relevant scaling of laser drying processes
for lithium-ion batteries is within reach
Innovative process technology enables energy-efficient drying of anodes andcathodes while at the same time reducing space requirements
As part of the IDEEL research project (Implementation of Laser Drying Processes for
Economical & Ecological Lithium-Ion Battery Production), project partners from industry andresearch are developing a laser drying process for the more climate-friendly and economical
serial production of lithium-ion batteries. Now, for the first time, the process has beensuccessfully scaled up to a coating and drying speed of 5 m/min in a continuous process,proving that industrial implementation is technically possible and economically viable.
Mülheim-Kärlich, 09.04.2024 – As part of the IDEEL research project, Fraunhofer ILT has
succeeded for the first time this year in scaling up the laser drying process in an R2R (roll-toroll) system from Coatema GmbH to a web speed of 5 m/min and demonstrating 2-stage
laser drying. This doubling of the web speed (compared to the previous year) was madepossible using laser beam sources and drying optics specially developed for therequirements of laser drying by Laserline. High-precision thermal cameras from Optris incombination with a laser power control system specially developed for this process ensure
homogeneous drying. In combination with the short response time of the laser beam sources
applied, this control concept enables highly dynamic process control. Furthermore, thethermographic images also enable reliable detection of defects in the electrodes - such as
variations in layer thickness or unwanted particles in the layers.
At the same time, the research and development team of the coating machinery companyCoatema optimized the drying and coating process using CFD (computational fluiddynamics) simulation to further improve the resulting electrode quality. The focus here wason improving the design of slot die geometry for the electrode coating process. In addition,
the prototype laser drying unit with optimized air flow was recently realized at Coatema inDormagen. This year, the laser optics developed by Laserline will be integrated into thesystem and the further upscaling of the drying process (up to 30 m/min) will be tested in theR&D Center of Coatema using high-power diode lasers.
Furthermore, the project partner PEM, Chair of Production Engineering of E-MobilityComponents at RWTH Aachen University, has succeeded in reducing the drying time for
LFP cathodes and graphite anodes by over 60 percent - and thus significantly reducing theenergy requirement and CO2 footprint as predicted. To further develop the process in termsof materials, the partners at MEET (Münster Electrochemical Energy Technology) Battery
Research Center at the University of Münster are currently working on new types of siliconcontaining anodes to increase the performance of the batteries. These new developments
are being tested for compatibility with the laser drying process in close collaboration withresearchers at PEM and the Fraunhofer Institute for Laser Technology ILT, and anynecessary adjustments are being made as required. Additional surveys conducted by theFraunhofer Research Institution for Battery Cell Production FFB among users from industry
and research also continuously provide new data on the current requirements for drying
processes. Thus, enabling application-oriented development work. This comprehensive
consideration of the overall system consisting of machinery technology, process and material
development not only allows the project participants to implement and demonstrate theprocess close to industry, but also makes it possible to drive forward the currently rapidlychanging battery production sector in Germany.

IDEEL Project:The IDEEL project (Implementation of Laser Drying Processes for Economical & Ecological LithiumIon Battery Production) is a research collaboration supported by the German Federal Ministry ofEducation and Research (BMBF) as part of the Battery 2020 funding program and led by Laserline
GmbH. The other project partners are Coatema Coating Machinery GmbH and Optris GmbH, aswell as the Fraunhofer Institute for Laser Technology (ILT), the Fraunhofer Research Institution forBattery Cell Production (FFB), the Münster Electrochemical Energy Technology (MEET) Battery
Research Center at the University of Münster and the Production Engineering of E-MobilityComponents (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 thatis 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) anda 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 toindustry-typical feed rates within a demonstrator (Coatema) and the physics-based model of thenew drying process subsequently validated (ILT, FFB).
The research results are to be incorporated into the FFB's processes in the future. The work of theFFB is considered one of the flagship projects of German battery research and is expected tobecome the principle development center of modern battery cell production for both Germany andEuropean 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 theMünster site, with the intention of providing support to companies and research institutions seeking
to test and optimize the series production of new battery designs.
Laser drying in the context of battery production:
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 isused 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 ofbattery production. The IDEEL project partners are therefore focusing on up-scaling a more energyefficient 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 formore flexible and precise process control compared to common convection technology, and wherethe 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 spacerequirements of the drying sections, which are typically more than 100 meters long – with asignificantly reduced spatial footprint for the production environment, the planning of new production
systems should enable faster and more energy-efficient process control.

Picture 1: 2-stage laser drying with a laser spot length of over 0.8m in the roll-to-roll battery drying
system. (Source: Fraunhofer ILT)

Picture 2: Electrode foil after laser drying (Source: PEM | RWTH Aachen University)