Spouted bed processing for structuring of conductive battery hetero-aggregates

Project Leader :

Prof. Dr.-Ing. habil.Stefan Heinrich
Hamburg University of Technology

In this project, a new type of spouted bed system is being optimised for the production of hetero-aggregate composites. The composites, which consist of three materials, should be suitable for use in solid-state batteries. The materials, whose primary particle sizes are between 40 nm and 10 µm, are provided within the SPP by Prof.Kwade's working group in Braunschweig and are candidates for the production of high-performance batteries. The composites are formed in the spouted and fluidised bed by mixing the individual components and by aggregation using interparticle adhesion forces. The main advantage of the method lies in the solvent-free and scalable process control. Initially, high-performance materials with a high energy density are coated with solid electrolyte in order to avoid side reactions in the battery.

Two new approaches are available: Firstly, the introduction of an aerosol in a spouted bed. And secondly, processing in a fluidised bed. In these systems, the coated composites are pre-processed and then analysed for their mechanical properties and characteristics. In particular, the stability of the aggregates and the distribution of the individual substances within the composites are decisive factors for later use in solid-state batteries. The coated particles are then processed into composites in the facilities and analysed for their properties and performance.

The electrochemical properties, in particular the ionic and electrical conductivity, are analysed in Giessen by Prof.Janek. The process parameters, such as solid mass flows, gas velocities, bed masses and other process parameters are varied through the exchange between the working groups within the framework of the SPP and the influence on the aggregate structure is thus analysed. This will determine the optimum conditions for producing high-performance composites for use in solid-state batteries. The basis of the project is the evaluation and extension of existing theoretical models for interparticle forces during dry coating.

Experimental and simulative investigations will be used to analyse and quantify the forces, such as cohesion, fracture and compression, that act on the particles during the processes. The flow in the system is calculated using a CFD simulation in order to determine the velocity trajectories of the individual particles. Using these values, the individual particle interactions can be simulated by DEM.
The aim of this work is to predict the behaviour during the dry coating and mixing process in a spouted bed using numerical models for the microprocesses. This can then be used for balancing the process using population balances, which in turn are required for implementing a model in the Dyssol flow sheet simulation software.