1 Series EV concept revealed

An electric vehicle concept based on the BMW 1 Series coupe will be the basis for a fleet of test vehicles to evaluate the car's viability in the field. Named the Concept ActiveE, the BMW will go on display to the public at the North American International Auto Show in Detroit next month.

BMW intends for the vehicle to go into series production, provided the fleet testing concludes successfully. As with the conventional 1 Series Coupe, the Concept ActiveE -- who makes up these names? -- will seat four.

The 125kW electric motor that powers the vehicle is mounted in the rear, driving to the rear axle and producing peak torque of 250Nm. Specifically developed for automotive applications by BMW and its partner SB LiMotive, the battery pack for the motor is supplied by a liquid-cooled lithium-ion pack. The pack occupies space reserved for the engine, fuel tank and driveshaft in a conventional car with an internal-combustion engine. All-up weight of the Concept ActiveE is 1800kg.

According to BMW, the Concept ActiveE can reach 100km/h from a standing start in under nine seconds, but the vehicle can cover a range of 160km between recharges. Based on a 240V domestic power supply, the recharge time from zilch to fully charged would be about three hours.

BMW settled on the 1 Series coupe as the donor for the Concept ActiveE, for reasons of its compact dimensions and light weight -- optimising the car's range -- but also because of the car's dynamic driving traits; something the company claims is largely retained in the Concept ActiveE.

Fitted with a synchronous electric motor, the Concept ActiveE offers power and torque output at higher motor speeds not dissimilar to the characteristics of a petrol engine. In other words, performance doesn't fall off to the same degrees as in asynchronous electric motors. BMW does limit the car's top speed to 145km/h.

The motor is integrated with the car's differential and thus occupies very little space. As with other electric vehicles, battery power can be recovered by the motor, acting as a generator on the overrun. Testing by BMW has revealed that the Concept ActiveE's range can be extended by as much as 20 per cent.

Addressing a concern expressed in the past that EV deceleration may pose a risk to drivers behind, BMW has equipped the Concept ActiveE with brake lights that operate when the vehicle is slowing, even if the driver doesn't apply the brakes.