E-Mobility Engineering 017 l ECE Doosan electric excavators dossier l In Conversation: Matt Faulks l Battery testing focus l Battery Show North America 2022 report l Ariel Hipercar digest l Cathode materials insight l Thermal management focus

cell. This stack was prepared in a controlled environment and filled with the electrolyte before sealing in a four-layer pouch foil of PET, oriented nylon, aluminium and polypropylene housing. The cells were produced in three batches at different times, with an average weight of 11 g, a theoretical capacity of 670 mAh and an estimated gravimetric energy density of 225 Wh/ kg. The structured methodology tested and validated the parameters that can be used to detect degradation in LMBs, and which should be non-invasive and can trigger self-healing mechanisms by a battery management system. Electron microscopes An electron microscope can also be used to monitor the workings of a battery cell. To that end, Researchers have built a lithium-air nanobattery inside the measurement column of a transmission electron microscope that allowed them to watch the battery charging and discharging. This showed a grey bubble developing on the battery’s flat surface that grew bigger. Later, the bubble deflated, the top turning in on itself until only a crumpled shell was left behind. techniques is based on parameters that track the evolution of cell ageing and a detection algorithm, validating the algorithm in its capability to detect failure. Dendrites form from inhomogeneities of the solid electrolyte interphase (SEI) that represents a highly conductive pathway for lithium ions. The concentrated ions are reduced, causing fractures in the SEI layer owing to volumetric expansion. The fractures represent suitable sites for deposition of lithium metal that forms dendrites. During an LMB’s cell’s early cycles, dendritic deposition is ‘mossy’ and then progresses in a fractal configuration when the lithium ion concentration reaches zero value at the interface between the anode and the electrolyte. High current density leads to a fast-growing fractal dendrite structure that can penetrate the separator and may cause hazardous internal short-circuits. The LMB cells used for the evaluation consist of lithium nickel manganese cobalt oxide as the active cathode, coated on top of a 15 µm- thick aluminium current collector, and a copper foil double-coated with lithium metal mixed with a small amount of aluminium as an anode material (99.7% lithium and 0.3% aluminium) and a monolayer polypropylene separator of 20-40 µm thickness. In the investigation a total of five cathode foils and six anode foils alternated with 12 separator layers were stacked into a pouch Some suppliers of thermal management equipment Complete systems Alvatek +44 800 566 8228 www.alvatek.co.uk Arbin Instruments +1 979 690 2751 www.arbin.com AVL +1 800 352 4343 www.avl.com Chroma ATE +1 949 421 0355 www.chromaate.com ITech ATE www.itech.sh Keysight Technologies +1 800 829 4444 www.keysight.com Maccor +1 918 446 1874 www.maccor.com Megger +44 1304 502100 www.uk.megger.com National Instruments +44 1635 523 545 www.ni.com Neware Battery +86 189 2840 4004 www.en.neware.com.cn PEC +32 16 39 83 39 www.peccorp.com Proventia Test Solutions +358 20 7810 200 www.proventia.com X-ray systems 3DX-ray +44 1509 817 400 www.3dx-ray.com Excillum +46 8 750 96 60 www.excillum.com Hamamatsu Photonics +44 1707 294 888 www.hamamatsu.com Hitachi High Tech +81 3 3504 7951 www.hitachi-hightech.com Kratos Analytics +44 1618 884 400 www.kratos.com Linev Group +1 936 588 2064 www.linevgroup.com MTIxtl +1 510 525 3070 www.mtixtl.com Nordson +1 877 667 3782 www.nordson.com North Star Imaging +1 763 312 8836 www.4nsi.com Uni ray +91 70453 01109 www.uniraymedical.com Using electron microscopy to examine bubble formation in lithium-air cells (Courtesy of PNNL) 38 January/February 2023 | E-Mobility Engineering