Electric motors and batteries in a circuit

Electric motors are key components of electromobility. Their inner workings consist to a large extent of sought-after metals such as copper and aluminum and rare earths such as neodymium. These are all materials whose recovery is becoming increasingly essential in view of the growing scarcity of resources and geopolitical dependencies. Over the past three and a half years, the Zirkel project, which is funded by the German Federal Ministry of Research, Technology and Space, has developed practical solutions for the automated dismantling and sophisticated recycling of highly integrated components from battery-powered electric vehicles. While part of the consortium concentrated on high-voltage battery storage systems, the Fraunhofer IWU focused on the electric motor and its material recycling.

Demonstrator for loosening screw connections

The screwdriving tool for loosening screw connections. © Fraunhofer IWU

How can bolted joints be loosened quickly and efficiently, even if the components are dirty or worn? In response to this key question, Fraunhofer IWU has developed an adaptive, robot-assisted demonstrator for the automated loosening of bolted joints. Instead of a classic industrial robot, a gantry robot is used. With the help of machine vision and AI algorithms, the system is able to recognize the position and condition of screw connections and loosen them in a targeted manner, which also works with heavily soiled or worn components.

The starting point was a multi-stage disassembly workshop at Fraunhofer IWU, in which rear-axle and front-axle engines from the Volkswagen Group were disassembled, analyzed and the process steps documented. This resulted in detailed disassembly instructions, which served as the basis for defining automated processes. The knowledge gained flowed directly into specific design recommendations for circuit-compatible constructions - for example to standardize screw connections or to improve the accessibility of connecting elements during disassembly.

Particular attention was paid to the magnets installed in the rotor, which contain the element neodymium, one of the most valuable raw materials for electromobility. Various remanufacturing processes were tested in the project, such as mechanical removal after prior separation of the laminated core or targeted removal using hydraulic presses. The result is a practical method for recovering and reusing the magnets with as little damage as possible.

The cycle only becomes economical with Design for Recycling

The aim of the project was to further develop disassembly and remanufacturing processes technologically so that even complex battery storage systems and electric motors can be largely automated and thus economically dismantled. Numerous processes and work steps now describe the path from CAD-supported dismantling planning to automated screw recognition and the experimental remanufacturing of magnetic materials.

The developed solution has the advantage of being adaptive, which significantly reduces set-up times. First of all, the system recognizes in a rough alignment that a component is in the disassembly cell. Subsequently (fine alignment), the system searches for joints that have already been taught in. Disassembly can now be carried out independently of the component; the only requirement is that the screw head has been trained once. Any number of screw heads can be trained. Standard stereo cameras are sufficient for the low-cost hardware solution developed. A key finding is that design for recycling must be an integral part of product development in order to close loops technologically and economically.

Fraunhofer-IWU, www.iwu.fraunhofer.de