Increasing electrification poses new challenges for the development of advanced lithium-ion batteries in terms of fast-charging capability, lifetime, safety, and manufacturing costs. The concept of a 3D-battery is an innovative approach that has the potential to greatly enhance the electrochemical performance of lithium-ion batteries beyond the current state-of-the-art. This is mainly due to the significantly shortened lithium-ion transport distances in 3D batteries and the strongly accelerated and overall homogenized electrolyte wetting and re-wetting of electrodes as a result of capillary effects. While the advantages of implementing laser-structured electrodes in coin cells, single-layer lab pouch cells, as well as in large-format multi-layered pouch cells in terms of increased cycle life and rate capability have been demonstrated, the demonstration in large-format cylindrical cells is still pending.
In the project “High-E-Life”, which is funded by the German Federal Ministry of Education and Research (BMBF, grant number 03XP0495), the project partners KIT, EAS Batteries GmbH, and EdgeWave GmbH are developing industrial reliable concepts for producing high power and high energy cylindrical cells by roll-to-roll ultrafast high-power laser structuring of electrodes. First results for the implementation of ultrafast laser structured thick-film electrodes (LFP/Graphite) in cylindrical battery cells will be presented. Suitable laser and process parameters like laser fluence and repetition rate were evaluated with regard to a possible thermally driven modification of LFP electrodes, and the generated 3D topographies were examined by scanning electron microscopy. Calculations for upscaling the laser structuring process to industrially relevant processing speeds are presented including advanced optical beam guidance concepts for high-throughput multi-beam materials processing. In addition, the appropriate choice of pattern type was analyzed according to cross-sections in terms of winding quality. It was demonstrated that the formation of cracks and delamination of thick film LFP electrodes can be prevented at small winding radii by applying an appropriate 3D structural design. Furthermore, comparative electrochemical analyses demonstrated that cells with structured electrodes outperform those with unstructured electrodes, especially in terms of high-rate capability.