The Grid 11 E-Mobility Engineering | May/June 2024 Electron beams offer faster, more precise welding Weight-saving composites for electric buses Cambridge Vacuum Engineering (CVE) is working with Ford on automating electron-beam welding, writes Nick Flaherty. The EB-eDrive project will examine how to scale up electron-beam welding for joining copper and aluminium components in electric motors. Ford Powertrain Manufacturing is working with CVE to find ways to reduce the time it takes to manufacture hairpin stators using electron-beam welding, which is faster and more precise than existing processes. Speeding up the welding of the stators could help increase the production of EVs. Electron-beam welding is significantly faster than conventional laser-welding techniques, and it is already used in wind turbines and nuclear reactor motors. The two companies have a scope of Exel Composites in Finland has developed a large-scale composite process for electric buses, writes Nick Flaherty. It has secured a project with Foton Bus and Coach in China to supply glassfibre composites, which will reduce the maintenance requirements and weight of the vehicles due to their corrosionresistant and lightweight properties. The geometric design flexibility of composites enables wider structural engineering possibilities than traditional metals, such as steel and aluminium. Exel Composites will produce a series of structural, composite profiles for many different bus models, including fibre-reinforced plastic (FRP) side panels, skirt panels and fake roofs. Pultrusion technology allows the continuous production of FRP structural shapes in an automated process by works, have drawn up preliminary designs and demonstrated some small samples of e-beam welding. “The potential benefits that electronbeam welding can bring to the production of motor stators is huge. As well as looking to reduce manufacturing times, pulling fibre glass through a resin bath or resin impregnator. The resin hardens from the heated steel pultrusion die, resulting in a strong, lightweight product that follows the shape of the die. This process offers greater tensile strength and durability, while reducing density we will be seeing what we can do to improve the quality of hairpin welds to reduce the risk of electrical shortcuts and the production of non-functioning stators,” said Bob Nicolson, CEO of Aquasium Technology, the parent company of CVE. Another CVE project, called EB-Bat, is a collaboration with Delta Cosworth and The Welding Institute (TWI) to design, build and test an electron-beam welding machine for battery busbar components. The CV EB welding equipment includes systems ranging from 50-200 kV with beam powers up to 100 kW. The current system developed by CVE can weld three strips of metal up to 250 mm long with a combined width of 3 mm. It has a 60 kV beam with a power of 10 kW, and it can weld the metal strips together in groups of 30. by 30% compared with traditional aluminium profiles. The weight savings provided by fibre glass, compared with aluminium, reduces the strain on the chassis and the battery. The composite panels do not rust and can last for decades. WELDING BUSES Composites for bus design (Image courtesy of Exel Composites) CVE and Ford are seeking to reduce the time it takes to make hairpin stators, the electromagnet system central to the smooth running of EV engines (Image courtesy of CVE)
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