When it comes to the BMW i3, disregard all that glass in the roof and the lower halves of the door, and you’ve got a pretty good idea of what the production variant of this two-box compact will look like. It’s sized like a Mini Countryman All4 with 10 inches cut off the nose, while a battery pack takes up much of the ground clearance and raises the floor a bit. The rear-hinged rear doors open after the front doors have opened. The construction concept BMW is calling LifeDrive can be considered the first production application of the skateboard chassis concept GM introduced as the AUTOnomy in 2002. It splits the car into a rolling aluminum chassis “Drive” module that bears all suspension and crash loading and carries the battery pack and the 168-hp/184-lb-ft rear-drive electric powertrain. The carbon-fiber-intensive passenger “Life” module attaches to this with four bolts and a lot of adhesive.
Extruded girders frame a large rectangular battery pack of 21-22-kW-hr capacity using an as yet undisclosed energy-biased lithium-ion chemistry which will likely be supplied by Saft. The suspension corners (strut front, multi-link rear) are supported by elaborate die-castings. BMW has developed its own AC permanent-magnet electric motor, which can vary its frequency to reduce the power loss typically experienced at higher rpm. The press kit amusingly refers to it as “permanently excited hybrid synchronous” (call your physician after four hours).
The carbon-fiber Life module monocoque is extremely light, and is comprised of body side apertures that look remarkably like those of a steel car. These assemblies are comprised of six or eight layers of uni-directional carbon fiber that are stacked in a heated female mold, then the heated male closes, resin is injected, and the part cures in a couple minutes. This process is quite similar to the one used to produce the Lamborghini Aventador passenger tub, but the cycle times are quicker (BMW is targeting annual production of 30,000 units). Crash repair is said to be a simple matter of sawing out the damaged section and gluing in a crash-repair section. Non-structural parts like the large single-piece roof panel are made using the short-fiber un-cured trimmings left over from the other operations, combed for some directional strength and cured to provide a class-A paintable finish. The unstressed outer body panels are thermoplastic, but because they’re mounted to a carbon-fiber structure with similar thermal expansion characteristics, the i3 should never suffer the wide panel gaps a steel-structured Saturn displays in the heat of summer.
Between the use of 50 percent recycled aluminum in the chassis and making interior panels and seats out of hemp fibers, recycled water bottles and the like, the lifetime global warming potential of the fully electric i3 is said to be a third less than that of a similar diesel 1-series hatch. That drops to half if recharged using renewable electricity. The Leipzig plant that will build the i3 will also consume 70 percent less water per vehicle and run on 100 percent renewable energy. But will the car be fun to drive?
BMW claims that in total, the i3’s electric powertrain weighs about 440 pounds more than a similar combustion setup, but its LifeDrive architecture trims 550 pounds, so when you floor the accelerator it will scoot to 62 mph in under 8 seconds. That sounds pretty fun as boxy hatchbacks go, especially since none of that drive will be muddying up the steering feel. Engage the ECO PRO mode (dulling throttle response and trimming output of all ancillary systems to their bare minimum) and you may coax 140 miles out of the battery. That’s the reported FTP72-cycle range, but BMW only claims 80-100 miles of realistic daily range. Not far enough? Opt for a range-extending two-cylinder motorcycle engine of about 600cc to maintain battery charge on longer excursions. BMW claims that drivers in the test fleet of Mini e electrics liked the heavy regenerative braking it provided when lifting off the throttle (I personally hated it), so that’s the way the i cars will be programmed as well. Hold steady or lift slightly and you’ll get coasting, lift a bit more and the anchor goes out, regen’ing more the more you lift.
Expect the i3 to go on sale in large metropolitan areas in 2013, and don’t expect it to be Leaf/Volt cheap. We’re guessing $45,000 at the minimum after government incentives.