Williams Debuts New Flexible Platform for BEVs and FCVs
The lightweight EVR can accommodate battery-electric and hydrogen fuel-cell propulsion.
Williams Advanced Engineering (WAE) has unveiled its latest product, the EVR electric vehicle platform. It has been designed to provide an accelerated start to a high-performance electric vehicle platform for OEMs.
As unveiled at the 2022 Low Carbon Vehicle Show at the Millbrook Proving Ground in the U.K., the EVR platform consists of a central carbon-fiber tub, supported on massive front and rear subframes. The tub is described as the core platform and has been designed so that it can be modified without needing new tooling.
The rear subframe carries the control systems, dual-motor drive system and suspension, while the front subframe carries the front suspension and steering hardware. A steer-by-wire system was fitted to the prototype; conventional steering also would be available. Steer-by-wire would enable either left or right-hand drive configurations without the need to modify the tub.
As displayed, the platform is equipped with twin-motor rear drive, but a single front-drive motor also is envisaged as an alternative. Regenerative braking will be a standard feature.
The platform has been designed to handle 1,650 kW (2,212 hp) of power, with around 680 Nm (502lb-ft) from the dual-motor platform. The prototype is fitted with an 85-kWh battery pack. Rapid charging using a 350-kW charger will provide an 80% charge in less than 20 minutes, the company claims.
The propulsion system is expected to deliver 0-60mph (0-97 km/h) acceleration in less than 1.9 seconds, with a projected top speed of around 350 km/h (217 mph). With a body fitted, the vehicle is expected to weigh around 1,800 kg (3,968 lb) in road trim – or in track specification with two-wheel-drive, around 1,650 kg (3638 lb). Williams has designed the platform to take either fixed-roof or open-top targa bodywork.
The battery is housed at the rear of the carbon-fiber tub where it forms part of the structure. The base of the battery is tied in with the rear subframe. The subframes are formed from both cast and extruded aluminum. The choice of horizontal suspension and damping hardware is to provide packaging space for drive components at the rear and space at the front for power electronics and front-drive motor when chosen. To date, testing has been virtual. Hardware testing is due before year’s end.
Fuel cell details
The project is the result of around 13 months’ work to date. While the prototype is a battery electric vehicle (BEV), WAE also is working on a hydrogen fuel cell (FCV) hybrid variant. The fuel cell would be intended as a lightweight, high-performance range extender. The battery pack would effectively be halved in size, to provide space for the fuel cell system and 100-L high-pressure hydrogen tank.
“When we have the hydrogen variant, we have a 40-kWh battery, as opposed to 85 kWh. Essentially, the way we’ve done this is by taking the same footprint-packaging model we’ve got for the BEV”, explained project engineer Sam Dew. “We’ve cut the battery in half, dropped it down and then we’ve dropped in the hydrogen fuel-cell unit and balancer plant around that package, just above where the battery currently is, where the battery would be in the EVR-H.”
This arrangement was chosen because it was the easiest place to accommodate it on this platform. The engineering team also considered packaging a fuel cell at the front of the vehicle, but found that they could not package enough capacity for the required power output. Accommodating the fuel-cell system at the rear also leaves space for a front drive motor for an all-wheel-drive variant.
“What we’ve done currently with the initial study on the hydrogen variant is that we’ve modelled it around a rear-wheel-drive-only variant and then we’ve packaged an additional hydrogen tank in the front, where on the other four-wheel-drive variants you would have a front EDU (electric drive unit),” Dew said., “So from a hydrogen tank point of view, we essentially package one tank at the front and two at the rear.”
While it is possible to get up to 200 to 250 kW by stacking fuel cells together, there wasn’t enough space to do that with the EVR platform. WAE opted for a 118-kW fuel cell stack, with an additional 400-450 kW coming from the battery electric drive system.
This should enable range to be extended to 500 to 600 km (310 to 373 miles). WAE expects the fuel-cell variant to reach the test rig stage by June 2023 and the end of 2023 before a prototype is ready.