ISSUE 011 Autumn 2021 Candela C-7 hydrofoil speedboat dossier l In conversation: Robert Hoevers l Battery recycling focus l Vehicle dynamics insight l ZeroAvia hydrogen-electric aircraft digest l Motor materials

Nick Flaherty explains the various methods of recovering valuable battery materials, and why new processes look like becoming necessary Cell division R ecycling batteries from e-mobility platforms, particularly lithium-ion and lithium iron phosphate (LFP) cells, is an area of increasing focus for the e-mobility industry. Sourcing lithium, cobalt and manganese, even copper, for batteries from around the world leaves battery manufacturing companies vulnerable to geopolitical forces that can disrupt or limit the supply of these key materials, so battery makers are looking to recycle more of the existing batteries. There are a number of very different approaches for recycling, some depending on the type of battery and others independent of format or battery chemistry. The coming generation of solid-state batteries could also lead to new approaches for recycling. Before recovering the metals within them though, the packs can be re- used in a ‘second life’ application such as stationary power storage. When they are no longer reliable enough for vehicles they can be used to store power from wind turbines or solar farms, for example, or even in the home to store solar power. For these applications, the battery management system (BMS) is a key factor. Wireless BMS connections on each pack give battery suppliers more options to re-use the packs, and the BMS nodes can be connected to different management software with machine learning algorithms that are optimised for stationary storage. This can extend the life of an e-mobility battery pack from 5 years in a vehicle to 10 or even 15 years. Tesla for example re-uses the packs from its vehicles in its Powerwall system for home energy storage. Nissan will re-use the packs from its Leaf vehicles to store energy from solar farms and wind farms that power the battery plant alongside its car-making factory in Sunderland, UK. But even these packs will need to be recycled, and different approaches are being adopted for this, with a focus on the speed of recycling. This is leading to changes in the design of the cell depending on the recycling approach, but it means that creating a universal recycling process is difficult. The problem is exacerbated by the fact that there are different formats for lithium-ion cells. Pouch cells are easier to dismantle, as they have flat sheets of electrodes and separators, while cylindrical cells need to be opened up and unrolled, and prismatic cells A copper sheet released from a battery by ultrasonic delamination (Courtesy of University of Leicester/ University of Birmingham/Faraday Institute) 32 Autumn 2021 | E-Mobility Engineering