HIF Projects in the GreenBattery Cluster of the Research Factory Battery
Sustainable support for battery research, establishment of battery cell production in Germany, faster transfer of research results to application: These are the goals of the German Federal Ministry of Education and Research (BMBF) concept "Battery Research Factory". The goals are being tackled in four new battery competence clusters, which the BMBF is funding with 100 million euros. The Helmholtz Institute Freiberg for Resource Technology (HIF) at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) is involved in the "Recycling & Green Battery" competence cluster with five projects.
Increasing and optimizing battery production is closely linked to the EU's climate targets (Green Deal), as batteries play a key role here. They are indispensable both as intermediate storage for the stabilization of decentralized power grids and for the implementation of electromobility. Due to their high energy density, lithium-ion batteries (LIBs) are currently the most important commercially available battery type for these applications. In order to reduce environmental impacts as much as possible, the useful life of the battery cells must be maximized and the material cycles of the raw materials must be closed. For this reason, the research projects are practice-oriented, so that promising solution approaches can be validated in the research production battery cell and transferred to industry.
Closing material cycles in the battery life cycle
The "Recycling & Green Battery" competence cluster, which is being funded with around 30 million euros, is laying the foundations for the sustainable recycling of battery raw materials and thus making an important contribution to closing material cycles. After all, the energy transition also includes the creation of a sustainable circular economy to reduce the consumption of natural resources. HIF is represented in this cluster in the BatMix project as coordinator and in the DIGISORT, ecoLiga, EarLiMet and HydroLiBRec projects as partner.
The concern of the BatMix project is to be able to quantitatively evaluate the future raw material mix for battery production. Currently, most of the raw materials used in LIBs (lithium, cobalt, nickel, graphite and manganese) are obtained by mining geogenic raw materials. In order to conserving natural resources and maximizing resource efficiency, it is essential to transition this as quickly as possible to a raw material mix of geogenic and recycling sources. However, the rapid growth in consumption currently places tight limits on recycling. The aim of the project is therefore to create statistically robust scenarios for the availability of the critical raw materials for battery production lithium, cobalt, nickel, manganese and graphite. Quantitative assessments will also be made for the CO₂ emissions and energy consumption that occur, and their expected development up to the year 2050. This allows the greatest efficiency potentials to be identified at the beginning of the supply chains. BatMix thus provides the most important approaches for future research projects to further optimize the "Green Battery".
On the way to a "green battery", a high recycling rate of recyclable materials is indispensable. This can be achieved through improved separation processes in the recycling stream. In the DIGISORT project, research is therefore being conducted into the digitization of mechanical separation processes in recycling using the example of wind sifting of shredded lithium-ion batteries. Wind sifting refers to a mechanical separation process in which particles are separated in a gas stream according to the laws of gravity and centrifugal force. The HIF contributes its expertise in characterizing material streams in the recycling process. In detail, the HIF will record on-line characteristic parameters of the recycling stream such as particle size, particle shape, material particle properties for input and product stream. For this purpose, crushed and non-crushed components of batteries will be detected and analyzed on a conveyor belt by a multi-sensor system (see figure). The development of these methods for a particle stream and the consolidation of the method-specific collected data in real time is a novel approach to digitalize the recycling chain. It also increases the sustainability of mechanical recycling processes. The development of the combined measurement technology with particle-discrete resolution aimed at here is an exemplary combination of application questioning and basic research, from which promising innovations can emerge. The measurement and control technology developed in DIGISORT can be used in the future along the entire recycling chain for quality monitoring and data acquisition. Moreover, the application is not limited to recycling processes of lithium-ion batteries, but can be adapted to a variety of other use cases.
The recycling and resynthesis of carbon materials from lithium batteries is the goal of the ecoLiga project. For this purpose, the sustainability with regard to manufacturing and recyclability of different carbon materials is balanced. This enables the recommendation of a suitable material and battery design to increase sustainability. In this way, battery manufacturing and recycling can be linked in terms of content and cooperation paths can be identified. Using lithium-sulfur batteries, it shall be shown that the active mass can be extracted using a suitable separation process. Graphite and carbon are recovered from the active mass by means of flotation treatment. The HIF is responsible for the processing of carbon particles by flotation. Furthermore, a holistic raw material recovery is carried out to maximize the recovery and finally the purification of the graphite and carbon material for resynthesis takes place. By combining these competences, an overall recycling concept can thus be pursued to maximize recovery and purity.
The EarLiMet project is pursuing a primarily hydrometallurgical approach for recycling lithium-ion batteries as completely as possible. It is expected that the hydrometallurgical process to be developed will enable significantly more raw materials to be recovered. Since lithium in particular is largely lost in conventional recycling processes, it is to be recovered from the so-called black mass right at the beginning of the process chain. This is done by enriching it with CO₂ to form lithium carbonate, which is subsequently dissolved out. In this way, 95% of the lithium is to be recovered in battery quality. Finally, a comprehensive material stream balancing is carried out by the HIF based in part on new analytical concepts. The analyses of battery recycling materials are indispensable to control and improve the recycling processes and to calculate the balances at the end. The HIF uses modern techniques such as electron microscopy and X-ray methods for raw material characterization. In addition, the HIF is responsible for the chemical characterization of the input material streams and coordinates the analytical quality assurance, because this is the only way to ensure the comparability and representativeness of the data generated by the partners in the project. The knowledge gained subsequently helps to select the appropriate processing methods. The project results and hydrometallurgical processes have enormous practical relevance for recycling companies, battery manufacturers and the environment.
The HydroLiBRec project links recycling and design with the aim of creating the technological prerequisites for effective, economically viable and environmentally friendly battery recycling. The project includes the disassembly of the battery pack, the function-preserving recovery of the active materials by chemical processing, the subsequent production of "recycled battery cells" and the creation of a digital twin of these and alternative process routes. The HIF will undertake the modeling of various processes and the creation of the digital twin, which will be used to evaluate and optimize the various process routes or derive design concepts for battery architecture. The generated process model should include not only all key battery raw materials, but also associated materials/components (enclosures; printed circuit boards); energy and water; products, residues, and emissions to evaluate the life cycle assessment and cost effectiveness of the different process routes. The concept for simulation-based, recycling-optimized design provides a universal tool that can be applied to other batteries of any type and size, enabling efficient resource use and cycling in a wide range of applications.