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Author: KIT
During the third semester, researchers from KIT further studied and improved the conditions for the mechanochemical transformation of black mass (BM) into metallic black mass (MBM). Since BM supplied by ACC is already in a reduced state, they focused on reducing BM supplied by TES. This BM consists mostly of NMC (lithium nickel manganese cobalt oxides) cathode material and graphite, which was found to slow down the reaction kinetics. The reduction of the cathode active material by the metallic reducing agent result in the formation of the transition metals along with lithium oxide (Li2O) and the oxide of the respective reducing agent, which can be monitored by X-ray diffraction.
In contrast to the previous two semesters, researchers switched from shaker mills to planetary mills, which enable control of the rotation speed and larger volumes that can be processed. Various parameters such as ball-to-sample ratio (BSR), ball size, total load and rotation speed were investigated to optimise for a short reaction time.
Main take-aways
In general, the higher the BSR, the more mechanical energy can be transferred per gram of powder which results in a more intense milling and a faster reaction; however, this limits the throughput. Larger balls, on the one hand, lead to higher kinetic energies. On the other hand, fewer balls are used to keep the BSR constant resulting in a lower collision frequency. The maximum rotation speed is lower to prevent damage to the grinding media.
With Calcium as the reducing agent, no reaction was achieved at all. An unfavorable combination of ductility and size of the calcium pieces seems to resist further size reduction, which is required for the reaction.
Aluminium has the advantage of being used as a current collector and is already present in the black mass. However, during the reaction, LiAlO2 is formed, which is limiting the subsequent Li extraction efficiency in WP5. This problem can be avoided when magnesium is used as the reducing agent, which proved to be more reactive than aluminium but doesn’t form other lithium compounds than Li2O.
Compared to the shaker mill, a higher reaction rate was observed in the planetary mill. Researcher from KIT achieved a complete conversion of the lithium transition metal oxide in the planetary mill within 3 h using Mg as the reducing agent. In a larger version of the mill, the required milling time increases to 8 hours. Here, further investigations are planned for the next months.
Read previous article on the pre-treatment operations: Pre-treatment operations: Reactive milling for the production of metallic black mass
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Benefits of “offline programming”
Simulation environments have been widely used in robotics for demonstration and planning purposes. This typically takes place within a simulation software or any other platform that can replicate the robot’s dynamics, workspace and surrounding environment, and enable robotic programming. This replication system has proved to be cost- and time-efficient due to a series of advantages: no risk of disrupting the production by removing the robot from the production line, high flexibility allowing infinite number of configurations on a virtual model of the robot, reduced risk of equipment damage due to high predictability of malfunctions. For instance, operational industrial robots can be tested in a simulation environment before deployment. This process is often referred to as “offline programming”.
Researchers at Department of Engineering Sciences, University of Agder have been designing a simulator within a virtual environment to visualise and test various demanufacturing approaches for battery packs, allowing them to collect necessary data such as process duration, disassembly tools – all without the need of physical experiments. This innovative exploration not only streamlines data gathering but can also help identify and remove unforeseen bottlenecks in the disassembly process.
Environment configuration and use case application for battery pack demanufacturing
Using a simulation environment, known for its high-fidelity graphical capabilities, researchers at UiA were able to create a controlled virtual space ideal for visualising complex robotic processes and interactions related to demanufacturing electric vehicle (EV) batteries. The robotic cell design is decomposed across all the subtasks/segments of the disassembly process, with specific consideration to safety aspects and optimised efficiency and accessibility of robotic manipulators.
In order to study in depth and to demonstrate the efficacy of a proposed fully automated demanufacturing line, researchers at UiA meticulously recreated a virtual environment where they simulated the disassembly of a an EV battery pack. This simulation encompasses the entire process from automated discharging to the disassembly of packs into modules, subsequent characterisation, sorting, and finally, the disassembly of modules into individual cells. All elements of the simulation are animated using the simulation platform and a robotic operating system code, providing a holistic view of the potential automation within the demanufacturing process.
For this particular use case, researchers at UiA have calculated the time individually for each disassembly operation, reaching roughly between 12 and 14 minutes for the entire process.
The findings of this research that replicated the complete demanufacturing of EV LiB pack in a virtual, yet realistic industrial setting, illustrate the leverage of automated processes over conventional approaches conventionally relying on manual techniques. The simulation provides estimates for operation time for a given disassembly procedure (disassembly sequence and disassembly process). Upcoming steps will involve AI to generate and optimise the procedures. Additionally, the simulation can identify solutions to minimise human exposure to potential hazards associated with battery disassembly processes. Future in depth and multidisciplinary research is required to optimise the disassembly sequences and process in the simulated environment by training reinforcement learning agents and including a collision avoidance system, to name a few.
Ultimately, the aim of this research is to anticipate the increasing number of EV batteries that will be decommissioned soon, and to ensure a proper management of waste, while recovering all the resources available in clean mobility technologies.
Discover UiA’s previous activities
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Despite a different objective, the RHINOCEROS project partners have shown growing interest in the Digital Battery Passport, an initiative of FREE4LIB, a sister project from the Cluster Hub “Production of raw materials for batteries from European resources”. This collaboration shows our commitment to contributing to the European battery community through the exchange of knowledge and experience.
The FREE4LIB workshop had a three-fold objective, including a brief presentation of the preliminary results of the battery passport concept development, the outline of the implementation challenges and potential follow-ups of industrial scale-up, and the clear differentiation between battery second use (B2U) versus recycling. The event drew approximately 50 participants from various segments of the battery value chain, which ensured a comprehensive and multifaceted perspective of the subject matter.
The introductive session presented the FREE4LIB project, briefly highlighting past achievements and focusing mainly on the remaining activities outlined in the workplan. The following session was led by Julius Ott (industrial engineer with expertise in circular economy at Karl-Franzens-Universität Graz). During the past year, researchers at Univ. of Graz worked on finalising data collection and processing related to the development of a data model of the digital passport platform which aims to close the information gap between beginning-of-life (BoL) and end-of-life (EoL) battery lifetime. This interactive session turned out to be an appropriate opportunity for researchers at Univ. of Graz to present the outcomes of their data collection and handling, and to evaluate their relevance within the reality portrayed by the workshop attendees.
Participants, predominantly familiarised with the EU-funded battery projects, confirmed the findings reported by Univ. of Graz. However, they also raised concerns about data sharing. The outcomes of the interactive session, complementing prior research, will serve as valuable guidance for the FREE4LIB project in implementing the battery passport within their project.
For additional background information on the digital passport developed by FREE4LIB, please refer to previous articles.
