BMW rolls out its first serial electrical vehicle

July 29, 2013 // By Christoph Hammerschmidt
Simultaneously in three different cities - London, New York and Shanghai - BMW today launched its first series production battery electric vehicle, the i3. With its lightweight design, relatively long driving range and its extensive selection of driver assistance systems raise the bar for the vendors to follow with electric car announcements this fall.

Due to its lightweight body, the four-seater offers a driving range of up to 160 km (100 miles) exclusively on battery. The optional range extender - a small two-cylinder four-stroke engine with a gasoline tank of just 9 litres - adds another 130 km to the range. Its 125 kW electric engine, powered through a 22kWh Li-ion battery accelerates the i3 to a maximum speed of 150 kmph. Within half an hour, it can be recharged to 80% of its capacity if a fast-charging device is used.

One of the reasons for its relatively long driving range is its lightweight construction: The passenger cell is made entirely of carbon which saves some 300 kg of weight compared to a car of the same size but with conventional steel body.


Fig. 1: With the electric motor (and the optional range extender) near the rear axle, and the battery in the bottom of the passenger cell, the BMW i3 achieves a weight ratio  of almost 1:1 between front and rear axle

To mute the range angst the vehicle comes with s Driving Range Assistant. It alerts the driver if the destination selected is beyond the vehicle's driving range. The assistant suggests switching to an "Eco Mode" (the i3 has two) which extends the range at the expense of temperament. It also suggests alternative, more economic routes. In case the battery has to be recharged en route, the system displays all available charging stations within reach. When computing the driving range, the system takes many parameters into account such as the driving style, the power consumption of in-car loads such as radio or lighting and even the topography of the route selected.

The i3 also is equipped with an adaptive cruise control which automatically supports stop-and-go traffic. A traffic jam assistant does not only keep the distance to the vehicle in front but also steers itself at low speeds. Other available options