Development of the Mercedes-Benz B-Class Electric Drive is moving along smartly since we first saw the thing in shimmering-blue-concept form at the 2012 Paris Motor Show. Now running about in prototype form, the B-Class ED is having some valuable cold-weather testing done in Sweden, as this box-fresh set of spy shots reveals.

If the concept car is a good indicator (it probably is) this prototype B-Class is likely making use of a Tesla-sourced lithium-ion battery pack, powering a 100-kilowatt electric motor. Initial estimates say that the B-Class ED should have a range of more than 120 miles, with a top speed in excess of 90 miles per hour.

The all-electric B-Class is expected to offer functionality along the lines of Toyota's large-hatchback Prius V, albeit with the loads of luxury features that befit any vehicle wearing the three-pointed star. The Electric Drive B-Class may be the only version of the vehicle that Mercedes-Benz offers for sale in the US – likely sometime late in 2013, as a 2014 model.