Experimental investigation of flow and segregation behaviour of bulk solids in silos under high gravity conditions

Many researchers have investigated the flow and segregation behaviour in model scale experimental silos at normal gravity conditions. However it is known that the stresses experienced by the bulk solid in industrial silos are high when compared to model silos. Therefore it is important to understand the effect of stress level on flow and segregation behaviour and establish the scaling laws governing this behaviour. The objective of this paper is to understand the effect of gravity on the flow and segregation behaviour of bulk solids in a silo centrifuge model. The materials used were two mixtures composed of Polyamide and glass beads. The discharge of two bi-disperse bulk solids in a silo centrifuge model were recorded under accelerations ranging from 1g to 15g. The velocity distribution during discharge was evaluated using Particle Image Velocimetry (PIV) techniques and the concentration distribution of large and small particles were obtained by imaging processing techniques. The flow and segregation behaviour at high gravities were then quantified and compared with the empirical equations available in the literature

Material characterisation for discrete element modelling calibration

The accurate determination of the microparameters needed in a Discrete Element Method (DEM) simulation is essential to obtain reliable results. In this work the DEM model parameters sensitivity in three different laboratory tests (single particle drop test, uniaxial particle compression and rotating drum) are investigated with respect to parameter value changes. The DEM parameters are varied by ± 25% from standard values. Materials used are 3.0 mm soda lime glass spheres and 3.0 mm polyamide spheres. Drop test simulations were sensitive only to change in coefficient of restitution parameter. The single particle compression test indicates that mainly the elasticity parameters influence the numerical response, Young’s modulus and Poisson’s ratio respectively. The sensitivity analysis indicates that the dynamic angle of repose in simulations depends on static as well as rolling friction coefficients

Digitalization Platform for Mechanistic Modeling of Battery Cell Production

he application of batteries in electric vehicles and stationary energy-storage systems is widely seen as a promising enabler for a sustainable mobility and for the energy sector. Although significant improvements have been achieved in the last decade in terms of higher battery performance and lower production costs, there remains high potential to be tapped, especially along the battery production chain. However, the battery production process is highly complex due to numerous process–structure and structure–performance relationships along the process chain, many of which are not yet fully understood. In order to move away from expensive trial-and-error operations of production lines, a methodology is needed to provide knowledge-based decision support to improve the quality and throughput of battery production. In the present work, a framework is presented that combines a process chain model and a battery cell model to quantitatively predict the impact of processes on the final battery cell performance. The framework enables coupling of diverse mechanistic models for the individual processes and the battery cell in a generic container platform, ultimately providing a digital representation of a battery electrode and cell production line that allows optimal production settings to be identified in silico. The framework can be implemented as part of a cyber-physical production system to provide decision support and ultimately control of the production line, thus increasing the efficiency of the entire battery cell production process

Optimizing Current Collector Interfaces for Efficient “Anode-Free” Lithium Metal Batteries

Current lithium (Li)-metal anodes are not sustainable for the mass production of future energy storage devices because they are inherently unsafe, expensive, and environmentally unfriendly. The anode-free concept, in which a current collector (CC) is directly used as the host to plate Li-metal, by using only the Li content coming from the positive electrode, could unlock the development of highly energy-dense and low-cost rechargeable batteries. Unfortunately, dead Li-metal forms during cycling, leading to a progressive and fast capacity loss. Therefore, the optimization of the CC/electrolyte interface and modifications of CC designs are key to producing highly efficient anode-free batteries with liquid and solid-state electrolytes. Lithiophilicity and electronic conductivity must be tuned to optimize the plating process of Li-metal. This review summarizes the recent progress and key findings in the CC design (e.g. 3D structures) and its interaction with electrolytes

Production of Nickel‐Rich Cathodes for Lithium‐Ion Batteries from Lab to Pilot Scale under Investigation of the Process Atmosphere

The selection of an appropriate cathode active material is important for operation performance and production of high-performance lithium-ion batteries. Promising candidates are nickel-rich layered oxides like LiNi$_x$Co$_y$Mn$_z$O$_2$ (NCM, x+y+z=1) with nickel contents of ‘x’ ≥ 0.8, characterized by high electrode potential and specific capacity. However, these materials are associated with capacity fading due to their high sensitivity to moisture. Herein, two different polycrystalline NCM materials with nickel contents of 0.81 ≤ ‘x’ ≤ 0.83 and protective surface coatings are processed in dry-room atmosphere (dew point of supply air T$_D$ ≈ −65 °C) at lab scale including the slurry preparation and coating procedure. In comparison, cathodes are produced in ambient atmosphere and both variants are tested in coin cells. Moreover, processing at pilot scale in ambient atmosphere is realized successfully by continuous coating and drying of the cathodes. Relevant electrode properties such as adhesion strength, specific electrical resistance, and pore-size distribution for the individual process steps are determined, as well as the moisture uptake during calendering. Furthermore, rate capability and cycling stability are investigated in pouch cells, wherein initial specific discharge capacities of up to 190 mAh g$^{−1}$ (with regard to the cathode material mass) are achieved at 0.2C

Impact of transport electrification on critical metal sustainability with a focus on the heavy-duty segment

The majority of transport electrification studies, examining the demand and sustainability of critical metals, have focused on light-duty vehicles. Heavy-duty vehicles have often been excluded from the research scope due to their smaller vehicle stock and slower pace of electrification. This study fills this research gap by evaluating the lithium resource impacts from electrification of the heavy-duty segment at the global level. Our results show that a mass electrification of the heavy-duty segment on top of the light-duty segment would substantially increase the lithium demand and impose further strain on the global lithium supply. The significant impact is attributed to the large single-vehicle battery capacity required by heavy-duty vehicles and the expected battery replacement needed within the lifetime of heavy-duty vehicles. We suggest that the ambition of mass electrification in the heavy-duty segment should be treated with cautions for both policy makers and entrepreneurs