The successful utilization of innovative sulfide-based solid-state batteries in energy storage hinges on developing scalable technologies and machinery for upscaling their production. While multiple Gigafactories for lithium-ion batteries are already operational worldwide, the upscaling of solid-state batteries exhibiting their full potential remains to be seen in the near future. In this study, the conventional production of lithium-ion batteries is reconsidered, and the feasibility of seamlessly integrating sulfide-based solid-state batteries into the existing process chains is discussed. Scalable technologies and key challenges along the process chain of sulfide-based solid-state batteries are accordingly addressed. Experimental investigations yield crucial insights into enabling large-scale production of sulfide-based battery components while highlighting remaining challenges from a production perspective. An overview of the roll-to-roll machinery housed in microenvironments under an inert atmosphere in the "Sulfidic Cell Production Advancement Center" at the Institute for Machine Tools and Industrial Management at the Technical University of Munich is given. Solid-State Battery Production: The current solid-state battery research is focusing materials rather than the battery's production making the scale-up from lab to fab a largely unknown field. This publication highlights the challenges and opportunities of sulfide-based solid-state battery manufacturing giving insights into experimental production research on roll-to-roll manufacturing comparing it to conventional lithium-ion battery production. image

All-solid-state batteries are a promising future cell concept to enhance energy densities and create an advantage in safety aspects in comparison to conventional lithium-ion batteries. They consist of solid components, including a composite cathode, a solid electrolyte separator and a lithium metal anode. To guarantee the functionality and high performance of the cells, a pronounced interfacial contact between those components in addition to a homogenous microstructure is essential to reduce ionic resistances and enhance mechanical stability. To produce sheets on a large scale, established processes such as mixing, coating, drying and calendering can be applied. The drying process is the most energy-consuming, space-occupying and cost-intensive process with major influence on the component’s microstructure and mechanical properties. As the latter is of particular importance for industry-relevant manufacturing, this research study focuses on the influence of process and product parameters on prevailing microstructural phenomena. Herein, composite cathodes and separators treated with different drying temperatures are analyzed by quantifying their adhesion strength and evaluating their particle distribution. Results show that the microstructure is changed at temperatures above 50 °C, leading to a significant loss of adhesion strength.

Sulfide-based all-solid-state batteries are one of the most promising next-generation energy storage systems. Especially the chlorine-rich argyrodite Li6PS5Cl (LPSCl) and the ceramic sulfide Li7P3S11 (LPS) are attractive solid electrolyte materials due to their high ionic conductivity. To date, research has focused primarily on material chemistry and cell design on a laboratory scale. From a production science point of view, process parameter studies and process engineering are rarely addressed. To fabricate a thin-film separator or composite cathode sheet, wet coating techniques from conventional lithium-ion battery production can be adapted. Therefore, this process study presents interdependencies for the upscaling of thin-film and large-scale sheets. LPSCl and LPS separators with thicknesses down to 40 mu m as well as composite cathodes containing the sulfidic solid electrolyte are coated and analyzed. In addition, relevant parameters such as viscosities and coating velocities are varied to quantify interdependencies. The results show, that depending on the solid electrolyte, slurry properties can be adapted and qualified for the wet coating process via doctor blade approaching the way for the industrial roll-to -roll coating process.

Energy storage systems play an important role in future applications for storing renewable electric energy with respect to slowing down climate change. In this context, the sulfide-based all-solid-state battery (ASSB) addresses the need for next-generation battery storage aiming at higher energy densities and increased safety. As known from current research, sulfide-based solid electrolytes show multiple electrochemical advantages, but the upscaling of suitable process technologies to fabricate large-scale components is still omitted. Adapting already known machinery from conventional lithium-ion battery (LIB) cell production might be possible, but most of the process and material parameters during manufacturing are unknown. However, a wet coating procedure might be applicable, but evokes the application of a downstream drying step. The drying process is the most energy- and cost-intensive step, where currently either water or N-methyl-2-pyrrolidone is evaporated from the LIB electrode slurry resulting in a dried thin-film sheet. For ASSBs, no analysis regarding drying rates, an important parameter in this process, is published so far. This study gives an overview of theoretical and experimental investigations on the drying behavior of composite cathodes and solid separators with sulfide-based electrolytes. These results enable the derivation of implications for the industrial drying process for all-solid-state battery components.

Researchers have been working for many years to find new material and cell systems that can be used as potential post-lithium-ion batteries. Among these, the all-solid-state battery is considered a promising candidate, with sulfide-based materials having essential advantages over other solid electrolyte materials, particularly in terms of their high ionic conductivity. A great challenge, however, is their high reactivity in contact with water, where harmful hydrogen sulfide (H2S) is formed. Since H2S formation has implications for both worker safety and material quality, it is important to quantify its impact. For this reason, this paper examines the relationship between the product properties and the H2S formation as well as influences resulting from the production environment. Exemplary material states along the process chain of a wet coating process route are analyzed for the steps of storage, mixing, coating, drying, and densifying with Li6PS5Cl (LPSCl) as a solid electrolyte material. By determining the H2S formation rate for sulfide-based separator sheets, it is shown that the water content in the surrounding atmosphere has the highest impact, while other investigated parameters are negligibly small in comparison. Among the product properties, the geometric surface and pore surface have a great influence. These results demonstrate the need for a controlled atmosphere in the production facilities at dew points of -40 to -50 °C. At those moisture levels, occupational safety and product quality are ensured for the investigated solid electrolyte sheets of LPSCl. This study is the first to provide quantitative data from the point of view of the production environment on the formation of H2S gas when using solid sulfide electrolytes and can therefore serve as a guideline for equipment, material, and cell manufacturers.

The all‐solid‐state battery (ASSB) based on a solid ionic conductor is a significant future concept for energy storage. In respect of the growing global demand for batteries, a systematic study on processing thin‐layer and large‐area ASSBs is addressed herein. As ASSB cells are mainly produced on a laboratory scale, an introduction to industrial production is needed. Therefore, the formation, ranking, and selection of technology chains are presented concerning the strategic orientation of cell manufacturing companies. A system model consisting of five sub‐models is created, which connects technologies with production‐relevant parameters. The results are used for a tool that automatically generates and evaluates technology chains in dependence of the ASSB cell design. Starting from the layer fabrication technologies further up‐ and downstream processes are defined. For sulfidic solid electrolytes, e.g., a ball milling followed by the aerosol deposition method, hot pressing, and laser cutting are favorable in terms of high‐quality layers and low production volume, whereas planetary mixing, tape casting, calendering, and die cutting are the choice for a high‐throughput production. Based on these findings, processing routes for every cell design and solid electrolyte material can be generated concerning company‐specific criteria, thus enabling the industrial application.

Sulfide-based all-solid-state batteries could enable applications with higher demands for safety and energy density. To support their market entry, the upscaling of current laboratory fabrication to industrial high-throughput production is necessary. This paper introduces a concept for an industrial coating process facing the sulfides’ main challenge – their reactivity with water in ambient air and the emerging toxic H2S. To produce cells cost-effectively and safely, different housings and atmospheres for the plant technology are evaluated. Adequate sensors, which measure the critical H2S content with regard to occupational safety during production, are addressed.

This manuscript analyzes different scenarios to estimate the manufacturing cost for small-scale and mass production of all-solid-state batteries.