Lithium-ion batteries are essential components of electrically and hybrid powered vehicles, stationary energy storage systems and portable electronics. When used in electric vehicles, the biggest challenge besides increasing the range is reducing battery costs. A reduction in battery costs can be achieved by using the same materials through more efficient production and improved battery quality. This is where the project “Roll-It” comes in. In this project, the process step of drying electrodes (anode, cathode) and separators directly before they are installed into battery cells is to be investigated.
This process step is necessary to reduce the water content of the battery cell to such an extent that neither the capacity nor the service life can be reduced due to undesired side reactions. Furthermore, drying is the most energy-intensive process step in battery cell production according to the current state of the art. Therefore there is enormous potential for saving energy and costs through improved process control while simultaneously increasing throughput. The basis for such a process improvement is a fundamental scientific understanding of the heat and mass transfer processes during drying.
The aim of “Roll-it” is to develop knowledge-based recommendations for the drying process, which can be used to improve existing processes in the industrial production of lithium-ion batteries while maintaining the same high cell quality and reducing waste, and to optimally design newly planned plants. In order to achieve the project goals, the relationship between cell properties and humidity is to be investigated and mapped using a suitable calculation model. Based on investigations on heat and mass transport, calculation models are developed with which the moisture can be described as a function of the type and intensity of heat input and drying conditions.