E-Mobility Engineering 015 l EMotive Scarab off-road truck dossier l In Conversation: Giulio Ornella l Hall effect and magnetic sensors focus l Challenge of batteries for heavy-duty EVs l Alpha Motor Corporation digest l Automated charging insight l HVAC systems focus

Rory Jackson gathers expert opinions on the best approaches to satisfying the battery power demands of large commercial EVs Big business H igh-voltage batteries are indispensable for the electrification and decarbonisation of vehicles worldwide, but the specific energy and energy density limitations of current battery technology bring challenges to the forefront when optimising different kinds of EVs. Take heavy-duty commercial EVs, for example. Whether electrifying an 18-wheel truck, a coach, a city bus or some similar sort of long- endurance fleet vehicle, hundreds of kilowatt-hours of energy need to be stored onboard. The problem here is that commercially available lithium-ion cells typically contain only 0.015 kWh/kg; even the very best, from r&d labs, rarely hold more than 400 Wh/kg. Also, given the amount of weight to be carried and the levels of vibration and environmental harshness likely to be endured, the cells must be housed in packs large enough to house extensive protection systems to prevent any damage to them. That piles on the weight though, forcing EV engineers to add more and more packs to ensure their vehicles have enough onboard energy to satisfy their range conditions. It also implies that high-voltage buses must be installed in order to deliver enough power to physically move such hefty EVs without severe current losses. None of this is really feasible. To force a way to a high-energy target in this manner would add up to thousands of kilos’ worth of battery packs – potentially as much weight in the battery as in the EV and its payload combined. And finding certified components at the desired voltages presents supply chain issues that can make the endeavour cost-ineffective or downright impossible. To understand how these challenging trade-offs can be resolved, we interviewed battery manufacturers to understand what their vision of the perfect pack for heavy-duty commercial EV applications would look like. Pack design and speci ication The initial steps for battery pack development vary between suppliers. For some, setting maximum constraints on collective pack weight or dimensions, as well as minimum targets on collective battery energy, can be useful for optimising pack parameters around the end-user’s application. With high-level targets fixed in this way, engineers can be freed up to test and simulate ways to remove weight at Electrifying heavy-duty commercial vehicles risks encumbering them with excessive battery pack weight unless innovative design and scientific advances are leveraged (Courtesy of Webasto) Akasol recommends packs of around 500 kWh weighing 500-600 kg and measuring 2 m long for heavy-duty EV applications (Courtesy of Akasol) 44 Autumn 2022 | E-Mobility Engineering