07 Fakultät Konstruktions-, Produktions- und Fahrzeugtechnik
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/8
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Item Open Access Enzyme-assisted circular additive manufacturing as an enabling technology for a circular bioeconomy : a conceptual review(2024) Protte-Freitag, Kristin; Gotzig, Sophia; Rothe, Hannah; Schwarz, Oliver; Silber, Nadine; Miehe, RobertAdditive manufacturing (AM) is a decisive element in the sustainable transformation of technologies. And yet its inherent potential has not been fully utilized. In particular, the use of biological materials represents a comparatively new dimension that is still in the early stages of deployment. In order to be considered sustainable and contribute to the circular economy, various challenges need to be overcome. Here, the literature focusing on sustainable, circular approaches is reviewed. It appears that existing processes are not yet capable of being used as circular economy technologies as they are neither able to process residual and waste materials, nor are the produced products easily biodegradable. Enzymatic approaches, however, appear promising. Based on this, a novel concept called enzyme-assisted circular additive manufacturing was developed. Various process combinations using enzymes along the process chain, starting with the preparation of side streams, through the functionalization of biopolymers to the actual printing process and post-processing, are outlined. Future aspects are discussed, stressing the necessity for AM processes to minimize or avoid the use of chemicals such as solvents or binding agents, the need to save energy through lower process temperatures and thereby reduce CO2 consumption, and the necessity for complete biodegradability of the materials used.Item Open Access Methodik zur Quantifizierung der nachhaltigen Wertschöpfung von Produktionssystemen an der ökonomisch-ökologischen Schnittstelle anhand ausgewählter Umweltprobleme(Stuttgart : Fraunhofer Verlag, 2018) Miehe, Robert; Bauernhansl, Thomas (Prof. Dr.)Nachhaltige Wertschöpfung ist das Diktum einer zukunftsfähigen Wirtschaftsform. Damit es gelingen kann, Produktionssysteme nach dieser Maßgabe zu konzipieren, ist eine quantitative Bezifferung von essentieller Bedeutung. Gründend auf den ethisch-normativen Lehren Immanuel Kants‘ und Hans Jonas‘, wird in der vorliegenden Arbeit nach einer kategorischen Objektivierung der Wertschöpfung an der ökonomisch-ökologischen Schnittstelle gesucht. Das hier vorgelegte Konzept erweitert die betriebliche Wertschöpfungsrechnung um die sozio-ökologischen Folgen produktionstechnischer Handlungen. Mit dem eco²-Value-Added wird ein rein pekuniärer Indikator präsentiert, der sowohl die betriebs- als auch die gesellschaftszweckdienlichen Effekte der Leistungserstellung zu inkludieren vermag. Einem produzierenden Unternehmen eröffnet das Konzept die Überprüfung der gesellschaftlichen Legitimation, die Antizipation von Unternehmensrisiken sowie eine zielorientierte Ausrichtung des soziotechnischen Systems im Hinblick auf die immanente Gerechtigkeitsherausforderung. Ebenso ist eine ordnungspolitische Verwendung des Ansatzes in Form gezielter Steuer- und Regelungsmechanismen möglich.Item Open Access Cradle-to-gate life cycle assessment of cylindrical sulfide-based solid-state batteries(2024) Rietdorf, Chantal; De la Rúa, Cristina; Kiemel, Steffen; Miehe, RobertPurposeSolid-state batteries (SSBs) are a current research hotspot, as they are safer and have a higher energy density than state-of-the-art lithium-ion batteries (LIBs). To date, their production only occurs on a laboratory scale, which provides a good opportunity to analyze the associated environmental impacts prior to industrialization. This paper investigates the environmental impacts of the production of cylindrical SSB, to identify environmental hotspots and optimization potentials.MethodsHere, an attributional cradle-to-gate life cycle assessment (LCA) is performed, focusing on SSBs that use a NMC811/lithium germanium phosphorous sulfide (LiGPS) composite cathode, a sulfide-based solid separator electrolyte, and a lithium metal anode. The life cycle impact assessment (LCIA) is performed in Umberto 11 using the Environmental Footprint 3.1 method with primary and literature data and the Evoinvent 3.9 database for background data.Results and discussionThe results show climate change impacts of 205.43 kg CO2 eq./kwh (for the base case), with hotspots primarily attributable to the electrolyte and cathode production, and more specifically to the LiPS and LiGPS synthesis as well as to the cathode active material. Additionally, the scenario analysis shows that an upscaling of the LiPS and LiGPS synthesis reduces environmental impacts across all assessed impact categories. In addition, it was shown that the use of an in situ anode further improves the overall environmental performance, while the use of alternative cathode active materials, such as NMC622 and LFP did not lead to any improvements, at least with reference to the storage capacity.ConclusionThe article highlights the environmental hotspots of sulfide-based SSB production, namely electrolyte and catholyte synthesis. The results show that upscaling the synthesis reduces the environmental impact and that cells with higher energy density show a favorable environmental performance. However, SSBs are still in the development stage and no final recommendation can be made at this time.