Reduce, Reuse, Repair, Refurbish, Remanufacture, Recycle: These are the six “R” strategies for a resource-efficient circular economy. Which of these approaches are suitable for electric drives, how can designs be optimized for this purpose, and what requirements must still be met to enable the reuse of valuable raw materials? At the upcoming VDI Congress DRITEV, Dr.-Ing. Daniel Heinrich of Schaeffler Automotive Buehl will provide insights into the current state and future prospects of the circular economy for electric motors. Ahead of the congress, he answered our questions.
In your opinion, which specific R strategies (Reduce, Reuse, Repair, Refurbish, Remanufacture, Recycle) are the most promising for high-voltage electric motors from both a technical and economic standpoint?
Daniel Heinrich: In our contribution to DRITEV, we focus on the question of how refurbishment and remanufacturing can be made possible. From both a technical and an environmental perspective, the goal is to preserve as much value as possible in an engine. This means that reuse, repair, and refurbishment are clearly preferable to recycling whenever possible. However: This must not lead to compromises in the quality of the motor. To put it bluntly: As little energy and material as possible, as much as necessary. This will always result in motors for which refurbishment is not a viable option and for which recycling is the best solution. The same applies: If we can restore a traction motor directly in the workshop using a repair kit, then this is clearly preferable to a refurbished or remanufactured component.
What economic thresholds must be met for remanufacturing processes for electric motors to become competitive with new production?
Daniel Heinrich: The goal is clear: remanufactured engines should have no disadvantages compared to new engines. Customers, whether on the OEM side or in the aftermarket, expect the same quality, durability, and performance as they do from new engines. In this article, we demonstrate that this goal is achievable by selecting the right approaches to engine design and qualification. From this point on, we can discuss economic aspects. These include not only the direct price but also sufficient availability of engines within a circular economy.
What measurement and diagnostic methods are necessary to reliably determine the degree of aging in windings, bearings, and magnets?
Daniel Heinrich: From a circular economy perspective, the ideal scenario would be to be able to assign a remaining service life to each component in a specific motor. In concrete terms, this would mean, for example, that the insulation still has 90 percent of its remaining service life available, but the bearings have already used up 60 percent of their remaining service life and are not suitable for a second service life. In this example, the bearings would then need to be replaced. However, precisely these measurement and diagnostic methods are not yet sufficiently robustly available. In practice, therefore, all we can say about the specific motor is that it has not yet failed. But that is not enough to make a reuse, repair, or remanufacture decision. We demonstrate that there is an alternative: We can qualify components in the electric motor in such a way that sufficient suitability for more than one vehicle life can be demonstrated, thereby eliminating the need to directly determine the state of aging for each individual motor.
What requirements does the circular economy already impose today on the configuration and, in particular, the design of new electric motors to facilitate disassembly, reuse, and recycling?
Daniel Heinrich: Our study shows that small changes to the design of electric motors can yield significant benefits in terms of their suitability for a circular economy. It is important to remember that motors manufactured today will still be eligible for material recovery in 20 years’ time – and with the current surge in production of traction motors, we have a very real opportunity to lay the groundwork for their future reuse within a circular economy.
Here, we distinguish between core motor components – which must be available for full circular economy – and interface components, which play a special role in disassembly and reassembly. Interestingly, we can easily distinguish between the two. Ironically, the components with the highest value, such as the rotor with its permanent magnets, are highly suitable for circular economy. Interfaces with other systems, such as a high-voltage terminal connecting to the power electronics, often have additional sealing requirements and are much more difficult to qualify for full reuse. However, replacing these components is well justified within the context of remanufacturing, resulting in a win-win situation for value recovery and sustainability.