E-Mobility Engineering 019 | In conversation: Stephen Lambert l WAE EVR l Battery case materials focus l Quality control insight l Clipper Automotive Clipper Cab digest l Optimising battery chemistries insight l Powertrain testing focus

mount, retool it, redesign it, put it back in, and then run an analysis to confirm that it works structurally,” McCaw says. “We’ve engaged with a Tier 1 supplier [their name withheld by an NDA] specifically for their skills in bonding multiple different carbon modules together. And in addition to considering the weave content of the carbon fibre and the lay-up analysis that goes with that, what’s becoming more prevalent is looking towards the end-of-life stage of the carbon fibre, and how we or our customers can make this a greener product beyond just electrification.” To that end, WAE is investigating opportunities for the use of natural fibre composites or recycled carbon fibre, and is eyeing the possibility of initially doing so in parts of the EVR (or other vehicles in the future) that are not structurally critical, for instance using chopped-strand SMC (sheet moulding compound) in some of the panel work. It is also researching the availability of more sustainable resins such as bio- resins, as well as easier recovery of the material’s fibre constituents by looking to use thermoplastic resins that can be melted or otherwise separated from the carbon fibres to enable them to be recollected at end of life. EVR rather than offering a hybrid- electric configuration as the baseline (although a hybrid powertrain can be designed and installed on request). As a result, the EVR has two seats with a low position, and 85 kWh of battery packs are installed behind the driver. Further back are the motors and inverters for driving the rear wheels in a single cylindrical housing. The Battista, C2 and Evija also provided benchmarks of the key performance parameters the EVR’s powertrain would need to have, particularly in terms of power output and acceleration. “Beyond that, we’ve made certain design considerations that allow us to either take the conventional approach of a solid steering column passing through the bulkhead, and a conventional brake booster with pushrod passing through, or to go with the by-wire approach,” McCaw says. “As we said earlier, drive-by-wire only started reaching production- level maturity in the past 2 years as far as we’ve seen, and some of our customers want to push the boundaries of technology and use innovative subsystems. But there are also others that want something more traditional; some have suggested they want hydraulic steering because they think the feel of that is above and beyond anything else that can be delivered right now. “So, we’ve made sure that either conventional or by-wire systems for steering and braking can be integrated into the EVR without having to redesign the whole front of the vehicle.” Carbon structure When it came to developing the structure of the EVR, WAE was initially tempted to build the skateboard around a carbon monocoque, as is typical for many of the aforementioned sports EVs. Depending on the model, they might also incorporate the suspension mounts and engine bay, for example. Instead, however, the EVR’s structure is typically composed of 12 pre-formed carbon fibre modules, which are then bonded together separately using proprietary adhesives to form the complete tub. “The advantage with that approach is that if a customer wants, say, a slightly different door seal design, maybe to suit their preferred egress route out of the vehicle, then rather than having to start again and redesign the tub, we can just take that one piece where the doors Dossier | WAE EVR The wheels are unlikely to be smaller than 19 in, as EVs built on the EVR are expected to feature CCM-R discs with six-pot calipers May/June 2023 | E-Mobility Engineering 25