Aston Martin first hinted that the company was heading down electric avenue in 2015 with the RapidE concept, and subsequently confirmed plans for a limited run all-electric Rapide last year. Few details escaped from Gaydon in Warwickshire back then, but that's now been rectified with the release of some tasty tech specs.
Aston's first battery electric is to be known as the Rapide E, and is being developed in close partnership with Williams Advanced Engineering. As stated in June 2017, production will be limited to just 155 vehicles, all built at a dedicated facility at the company's St. Athan site.
The vehicle will sport two rear-mounted electric motors producing more than 610 PS (640 horses) and 950 Nm (700 lb-ft) of torque. Top speed is projected to be 155 mph (250 km/h), standstill to 60 mph (96.5 km/h) will be under the four second mark and 50 to 70 mph (60 - 112 km/h) will take 1.5 seconds – whether the batteries are at full capacity or not. On-demand battery performance "includes the ability to drive a full lap of the Nürburgring with absolutely no derating of the battery and the ability to cope with the daily demands of repeated hard acceleration and braking."
The Rapide E's 800 V battery system is made up of 5,600 Li-ion 18650 format cylindrical cells with a total capacity of 65 kWh and mounted where the gearbox and fuel tank of the original Rapide were located. Range per charge is expected to be over 200 miles (320 km) to WLTP standards – Aston is promising 185 miles worth of charge for every hour hooked up to a 400 V/50 kWh charger, but fast charging is also possible.
The exterior and underbody have been aero-optimized for the electric version of the 6-liter V12 Rapide, and the car has been treated to a fresh set of aerodynamic wheels wrapped in Pirelli P-Zero low rolling-resistance tires (which feature noise-canceling foam). Aston says that it will be using lightweight alloys and carbon composites to stay within strict weight targets and is also tweaking and tuning the powertrain, chassis and software to retain the feel of the original V12-powered Rapide, combining a Limited-Slip Differential with revised spring and damper rates to match the handling characteristics of the Rapide S.
First deliveries are scheduled for Q4 2019 but we'll doubtless see much more of the Rapire E before then. Interested buyers are now being invited to express an interest, with pricing revealed on application. And Aston closes this specs reveal by saying that comments and driving experiences from owners will be taken on board to shape the development of future Aston Martin electric vehicles, confirming that we can expect more EVs from the company in years to come.
Source: Aston Martin
I've driven an EV for over four years, and this is the first time I've ever heard anyone suggest that use of the battery might cause any kind of degradation of performance. EVs aren't some sort of inverse of ICE, in which the decreasing weight of fuel in an emptying tank allows greater acceleration.
The only degradation I know of that's ever associated with EV technology is a gradual reduction in the full-charge battery capacity of some of the early (and current low-cost) models. Well designed battery systems like that in the Tesla and, I'm happy to report, my Fiat 500e show virtually no such degradation, even after years and tens of thousands of miles of use.
A motor for each wheel would make a differential redundant.
Cars have a differential because they have one power source, internal combustion engine or electric motor, driving two wheels. During cornering, all four wheels of a car rotate at different speeds, so there is a differential in the speeds of the two wheels driven by the engine. Without differential gears the two driven wheels would be rigidly connected together, so if the car is steered the two driven wheels would have to skid against each other, making steering difficult. The forces between the two wheels oppose the steering input, causing understeer even at walking speed. Think of rolling a log. The two ends of the log are rigidly connected to each other, so the log (or Flintstones car) can only be steered by skidding it around, left or right.
If you put a car on a hoist, handbrake off, and rotate a driving wheel by hand, the wheel on the opposite side of the car will rotate in the opposite direction, due to the differential gears. The differential gears are usually four “spider” bevel gears in the centre of the final-drive unit. A standard “open” differential has the disadvantage that if one wheel loses traction, only limited power can be applied to the wheel that still has traction, as the same torque is applied to both. A limited-slip differential has a traction advantage as it limits the “slip”, or difference in speed, between the two wheels, and can therefore apply more power to the wheel that still has traction than is the case with an open differential. Off-road vehicles can lock their differentials to improve traction on loose surfaces.
This electric car does not require a differential, as the two rear wheels are not connected mechanically. The two motors will simply run at different speeds while cornering. Similarly, a motorcycle does not require a differential, because it has one engine, driving one wheel. There are no speed differentials to take care of. A Segway or tracked vehicle (bulldozer or army tank) steers by controlling the difference in speeds between its two wheels.
You may be reporting on the latest electric car developments, but you should not be ignorant of century-old mechanical bits that are still relevant. They may be applied differently in electric cars, because internal-combustion engine cars ordinarily have only one engine.
So please stop confusing final drives with differentials.