12 September/October 2023 | E-Mobility Engineering The Grid AM advance in stator production Reliability boost for aluminium cells Researchers in the US and UK have used additive manufacturing (AM) to develop a 3D-printed motor with materials previously considered too brittle to use (writes Nick Flaherty). The researchers, at the University of Sheffield in the UK and the University of Wisconsin-Madison in the US, have developed a 10 kW prototype motor they are scaling up to 40 kW for e-mobility applications. The prototype uses a stator built from electrical steel with a higher percentage of silicon, 6.5%, rather than the 3% in today’s motors. This more brittle steel reduces energy losses but could not previously be reliably used for the laminations in the stator. Using AM also allowed the researchers to implement The stator has 30% less steel than other motors Researchers in the US have developed a high-power solidstate battery using aluminium that avoids previous reliability issues (writes Nick Flaherty). The team, from the Georgia Institute of Technology, worked with Novelis, which manufactures aluminium and is the world’s largest aluminium recycler. Despite an energy capacity of 990mAh/g without changing its volume, aluminium tends to fracture during charging and discharging, and so fails after a few cycles, so the researchers tested more than 100 versions with different materials added to the aluminium foils to understand their behaviour in a solid-state battery. The project combined non-pre-lithiated aluminium foil negative electrodes with microstructures of indium in a solidstate lithium-ion cell. The 30 µm-thick Al94.5In5.5 negative electrodes were a different stator design with more intricate geometric lines that further reduce energy loss. The design of the stator was developed at Sheffield using its AM systems and tested at UW-Madison. It showed an improvement in torque density of 22% by using 30% less steel. The printing process took 20 hours for a stator for the prototype. This could be scaled up to one suitable for a 40 kW motor using an industrial AM system. “When you have 30% lower mass, you would expect that your torque would also be lower, but that wasn’t the case,” said FNU Nishanth, post-doctoral research assistant at UW-Madison. “So this shows that you know you’re actually going to get a net torque density improvement in this machine, and if we can further improve combined with a Li6PS5Cl solid-state electrolyte and a LiNi0.6Mn0.2Co0.2O2based positive electrode in a cell that delivered hundreds of stable cycles with high current densities of 6.5 mA/cm2. The chosen microstructure enables improved charging and discharging within the aluminium matrix, opening up the use of aluminium batteries in EVs and aircraft, according to the team. this, making a more efficient motor would be a game-changer.” Alexander Goodall, a doctoral student in the Department of Materials Science and Engineering at Sheffield, said, “This project has shown the large potential that AM has for electrical machines, with lightweight, efficient structures that have never before been possible using any other manufacturing technique.” “We needed to incorporate a material that would address aluminium’s fundamental issues as a battery anode,” said Yuhgene Liu, a PhD student and researcher on the team. “Our new aluminium foil anode demonstrated markedly improved performance and stability when implemented in solid-state batteries, as opposed to conventional lithium-ion batteries.” MOTORS BATTERIES The solid-state cell could be used in EVs and aircraft
RkJQdWJsaXNoZXIy MjI2Mzk4