Six-roll calender for dry coating

• Subject Area: Production Technology
• Term: Funded in 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 533952183

In the present application, a dry coating line for battery cell production is to be procured. Battery cell production can be divided into three areas, electrode production, cell assembly and cell finishing. The industry standardized process for battery electrode production is currently based on wet chemical coating processes, where the active material is applied in the form of a suspension onto a metal foil. The suspension is prepared by a prior mixing process of the active material with a solvent. This is applied to the metal foil via an application system. To ensure high quality of the electrodes produced, the removal of the solvents used, some of which are toxic, is of great importance. This results in high production, area and energy costs, which account for about 5% of the total cost of a battery cell. As an alternative for this very energy- and area-intensive process step, the dry coating process is currently being investigated in more detail and is becoming the focus of current research efforts due to its potential. Prior to the process, the dry active material, binders and additives are homogenized and preconditioned in a mixing process. In the actual dry coating process, this mixture is pressed by rollers to form 50-100 micrometers thin electrode films on a current collector as substrate. In operation, the dry mixture is fed into the system from both sides via a material feed to enable simultaneous double-sided coating. In addition to negative environmental influences, the evaporation of the solvent during the conventional drying process can also have a negative effect on the electrode structure and defects and lead to a reduction in cell quality. The dry coating process is not limited in terms of film thickness and allows processing of additives and active materials that are difficult to disperse. The technology has hardly been investigated, especially in research, so not all interactions between process and product as well as the optimal integration of the technology as a replacement for the conventional oven have been explored yet. In order to validate the listed assumptions about dry coating and to be able to design the technology including processes for large-scale production, scaling up from a pilot line is necessary. This results in a need for research that will increase continuously and extend to other and future cell technologies. The PEM would like to support these research activities and investigate the open questions regarding this technology in their own pilot production. For this reason, an application is being submitted for the procurement of a dry coating system via the large-scale equipment application.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Sechs-Walzen Kalander zur Trockenbeschichtung
• Instrumentation Group: 2290 Sonstige Bearbeitungsmaschinen für nichtmetallische Werkstoffe
• Applicant Institution: Rheinisch-Westfälische Technische Hochschule Aachen
• Leader: Professor Dr.-Ing. Achim Kampker