Spouted bed processing for structuring of conductive battery hetero-aggregates

在本项目中，将建立一种新的喷动床干法涂层工艺，该工艺能够制备出适合于全固态电池使用的三种材料组成的异质聚集体。这些一次颗粒尺寸从40纳米到约1微米的材料将由布伦斯韦格的夸德教授的工作组在SPP内提供，类似于生产高性能电池的候选材料。由于内聚力的作用，复合材料将在喷动床内通过混合材料和产生集合体来形成。这种新方法的主要优点是避免了危害健康的溶剂，在喷动床过程中作用的作用力很大，同时具有放大潜力。为了能够同时处理喷动床中的三股固体气流，将评估两种关于固体喷射的新的、不同的方法：中心喷嘴状喷射和与流态化气体一起喷射。因此，将对现有的小型喷动床装置进行改造，然后生产第一批复合材料，并对其机械性能和组成进行评估。尤其是聚集体的稳定性以及不同材料在聚集体内部的分布是决定其在固体电池中应用的关键因素。复合材料的电化学性质，特别是电导率和离子导电性以及化学稳定性将在布伦斯韦格进行研究。通过接收我们合作伙伴的反馈，将改变工艺参数(例如固体质量流量、气体速度和床层质量)，以实现对工艺参数和聚集体结构之间关系的基本了解，并生产出性能最佳的聚集体，用于全固态电池。这项工作的基础将是评估和扩展现有的干涂覆过程中作用于特殊作用力的理论模型。通过实验和模拟的方法，对喷动床过程中作用在颗粒上的力(凝聚力、破碎力、压缩力)进行了实验和模拟分析。工厂内的气流将由CFD模拟，以确定颗粒轨迹的速度，这表明作用在颗粒上的最高应力。有了这些知识，就有可能在DEM中模拟特定的相互作用。这项工作的目标是能够通过数值描述微过程来预测干燥涂层喷射过程中的行为。之后，将有可能通过人口平衡来描述这一过程，这将被用来创建用于流程图模拟(Dyssol)的理论模型，并为计划在第二个资助期对该过程进行进一步的CFD-DEM模拟奠定基础。

In this project, a novel spouted bed dry coating process will be established, which is able to fabricate hetero aggregates consisting of three materials, that are suitable for the use in all-solid-state-batteries. The materials, with primary particle sizes ranging from 40 nm to around 1 µm, will be provided within the SPP by the working group of Prof. Kwade in Braunschweig and resemble candidates for the production of high-performance batteries. The composites will be formed inside the spouted bed by mixing the materials and creating aggregates due to the cohesive forces. The main advantage of this novel method are the avoidance of dangerous-to-health solvents, high forces acting in spouted bed processes and at the same time a scale-up potential. To be able to handle three solid streams in the spouted bed simultaneously, two new, different approaches regarding the injection of solids will be evaluated: a central nozzle-like injection and an injection together with the fluidization gas. Therefore, an existing miniaturized spouted bed plant will be reconstructed and afterwards the first composites will be produced, which will be evaluated regarding their mechanical properties and their composition. Especially the stability of the aggregates as well as the distribution of the different materials inside the aggregate are key factors, which determine the later application in solid-state batteries. The electro-chemical properties of the composites, especially the electric and ionic conductivity as well as the chemical stability will be investigated in Braunschweig. By receiving feedback from our partners, the process parameters (e.g. solids mass flows, gas velocities and bed mass) will be changed, to achieve a fundamental understanding of the relationship between process parameters and aggregate structure and produce aggregates with the best properties for the use in all-solid-state batteries. The foundation of this work will be the evaluation and expansion of existing theoretical models for interparticular forces acting during dry coating processes. By using experimental as well simulative methods, the forces (cohesion, breakage, compression) acting on particles during a spouted bed process will be analysed experimentally as well as by simulation. The gas flow inside the plant will be modelled by CFD to determine the velocities of the trajectories of the particles, which indicate the highest stresses acting on the particles. With this knowledge it is possible to simulate the particular interactions in DEM. Goal of this work is the ability to predict the behaviour during a dry coating spouted process by describing the microprocesses numerically. Afterwards, it will be possible to describe the process by population balances, which in turn will be used to create a theoretical model for the use in flowsheet simulations (Dyssol) and lay the foundation for further coupled CFD-DEM simulations of the process, which are planned for the second funding period.