The Mercedes' motor, which was co-developed with Tesla, outputs 134bhp and 230lb ft of torque.
Power comes from a battery pack mounted under the floor, which is claimed to be rechargeable from flat in four hours.
Despite the motor's relatively high output the B-class is claimed to have a maximum range of 115 miles. Nissan's recently updated Leaf, however, offers a maximum range of 124 miles.
Mercedes states that a two-hour charge will grant the B-class a range of around 60 miles, useful for those who intend to use it regularly.
Inside, the B-class remains much unchanged - but drivers do benefit from additional readouts for the vehicle's power system. The Mercedes also gets a smartphone integration system that allows owners to control functions like preheating.
Mercedes sales boss, Joachim Schmidt, said that he was "Convinced more and more people see zero emissions cars as making sense"
He also commented that "electric vehicles will be a major part of sustainable motoring".
The new Mercedes-Benz B-class Electric Drive, which will be offered in the US initially, will be available to order in the autumn. Sales are expected to start in early 2014.
Thanks to: Autocar
