Insights into dry battery electrode manufacturing: Unveiling the patent landscape

The advent of lithium-ion batteries (LIBs) has resulted in increased requirements and demands, which has in turn led to the upscaling of manufacturing to gigafactory scale. At this scale, energy consumption and production costs represent crucial targets for innovations. Both targets are simultaneously addressed by dry battery electrode (DBE) manufacturing, through the elimination of toxic solvents and the subsequent omission of the energy-intensive drying procedure. Additionally, it has the potential of improved performance and compatibility towards the production of all-solid-state batteries (ASSBs) compared to solvent-based coating. Prior research either focuses on laboratory-scale applications or summarizing research advancements. Consequently, a gap regarding the application of data science analysis in the field of dry coating remains in literature. To fill this gap, a dataset comprising the four primary DBE manufacturing technologies, devices and materials is subjected to an in-depth analysis. This analysis addresses the historic evolution of each technology and the underlying processes, thereby identifying the calendering mechanisms that employ binder fibrillation as the major fields of interest, offering the biggest revenue. The breakdown by region and assignee identified the United States, particularly Tesla and Maxwell, as the pioneering actor in free-standing calendering of DBEs, both in terms of total number and impact of the portfolio. However, the recent expiration of the initially patented free-standing calendering technology by Maxwell has paved the way for several other companies to innovate and extend the approach, with LG Chem currently leading the way with 74 applications. The examination of the chemistries and binders indicated a growing interest in ASSBs and binder systems without per- and polyfluoroalkyl substances (PFAS), suggesting that both fields demonstrate the greatest innovation potential in conjunction with the successful implementation of the DBE calendering technologies.