The field tests with the MINI E as part of Project i in the US and Europe have already provided insights into the demands required of future production electric vehicles. As a second step, project i has begun development of a second trial fleet of electric vehicles based on the BMW Concept ActiveE. These vehicles are likewise intended for everyday use by private and select fleet customers as part of a large-scale field test.

The insights gathered in the process will be fed into the development of an electrically powered serial production vehicle which the BMW Group will put on the market under a sub-brand of BMW in the first half of the next decade.

The BMW Concept ActiveE has allowed BMW to explore new vehicle packaging solutions and components which will be crucial to the success of the Megacity Vehicle. The intelligent integration of drive components within the existing vehicle package of the BMW 1 Series Coupe offers the opportunity to provide four full-size seats and a luggage compartment with a capacity of 200 litres / 7 cu ft.

The BMW Concept ActiveE. Click to enlarge.

Motor. The motor, specially developed for the model and located in the rear axle, delivers 125 kW/170 hp and provides maximum torque of 250 N·m/ 184 lb-ft. It accelerates the vehicle in less than 9 seconds from zero to 100 km/h (0-60 mph in approx. 8.5 seconds).

Unlike asynchronous electric motors, the new power unit provides a relatively high level of torque even at higher engine speeds and road speeds; at increased load the torque is not reduced abruptly but decreases gradually. The torque curve at higher engine speeds is therefore much more similar to the pattern familiar from combustion engines.

The compact power package is fully integrated in the rear axle of the BMW Concept ActiveE. Here the drive system occupies the space required in conventional vehicles by the differential, whose function is integrated in the drive system.

The optimum positioning of the power electronics above the motor integrated in the rear axle, for reasons of safety and functionality, does result in a reduction of trunk capacity.

Battery pack. The electric drive system is equipped with an advanced liquid-cooled lithium-ion battery pack developed jointly by BMW and the co-operation partner SB LiMotive especially for the BMW Concept ActiveE. The pack enables a range of about 160 km / 100 miles on a single charge, depending on conditions (FTP72 cycle range is calculated to be 240 km / 150 miles in simulation).

The battery pack is located where a combustion engine and fuel tank would normally be located. The largest portion of the battery pack in the BMW Concept ActiveE is located where the conventional propshaft and fuel tank would be in the lower section of the vehicle. In addition, a portion of the battery pack is located where the combustion engine would normally reside. Using intelligent lightweight design and the efficient lithium-ion battery cells, vehicle curb weight is limited to about 1,800 kg / 3,900 lbs.

The positioning of the battery pack also shifts the vehicle’s center of gravity downwards. The battery cell layout within the vehicle preserves the near 50-50 weight distribution characteristic of BMW vehicles. In this respect, the BMW Concept ActiveE offers ideal conditions for driving experience characterized by a high level of agility.

An intelligent battery management system helps achieve this range largely independently of external climatic conditions. Additionally, the charging period required for the lithium-ion batteries is very short. On the European power grid, the battery pack can be fully charged in just 3 hours at a wall box with a current of 50 ampere at 230/240 volts. In North America, using a high-current (32 ampere continuous) residential wall box, the charge time is about 4.5 hours.

Braking. In the purely electric powered BMW, the driver may control deceleration as well as acceleration through the movement of the accelerator pedal. As soon as the driver’s foot is removed from the accelerator, the electric motor performs the function of a generator, converting the vehicle’s kinetic energy into electric power and storing it in the battery pack. Intensive use of this energy recuperation process by the motor increases the range by up to 20%.

At the same time, a brake torque is created which results in effective deceleration of the vehicle. This response enables a very comfortable driving style, especially at medium and constantly varying speeds. In urban traffic, some 75% of all deceleration manoeuvres are initiated without the need for the brake pedal. During Brake Energy Regeneration function, the vehicle’s brake lights are illuminated.

This brake effect acts on the rear wheels only. When the driver requires a higher level of deceleration, stepping on the brake pedal engages the conventional hydraulic braking system. If an emergency braking maneuver is required during braking, the Dynamic Stability Control (DSC) system applies selective braking and motor management measures to ensure that safe braking is always guaranteed.

The brake system is fitted with an electric vacuum pump which is activated on demand. Along with the Electric Power Steering (EPS) familiar from the production models of the BMW 1 Series, these features contribute to an increase in the overall efficiency of the vehicle.

HVAC. In conjunction with the battery technology, the concept of a purely electrically powered vehicle presents additional opportunities for the integration of innovative comfort features. For the BMW Concept ActiveE, a special heating and air conditioning system was developed which is supplied with energy from the high-voltage battery via the vehicle power network. The fact that the heating system and air conditioning compressor are electrically powered means that the desired temperature can be provided inside the vehicle even when it is stationary.

The driver can heat or cool the interior before a trip using the auxiliary heating or air conditioning system—an option which is available when the vehicle is connected to a charging station and the battery is fully charged. This ensures that the range is not reduced by the comfort function, but in fact increased. The reason for this is that the energy required for heating or cooling the vehicle with an existing connection to the power supply does not need to be drawn from the battery during travel.

The climate control systems developed for the BMW Concept ActiveE can also be activated via mobile phone. This option also includes a timer function so the driver can ensure that the vehicle is conveniently pre-cooled or pre-heated before getting into it in the morning, for example. Climatic pre-conditioning optimizes not only ride comfort but also the operating status of the energy storage system in the sense that it maximizes the range of the vehicle. The control of the heating and air conditioning system by mobile phone is made available through BMW ConnectedDrive.

Other ConnectedDrive Services. BMW ConnectedDrive offers additional services specially developed for the BMW Concept ActiveE. The main focus here is on the user-friendly and practically oriented relay of precise information on the condition of the vehicle. The driver can obtain details of the charge status of the lithium-ion battery and the range of travel this permits regardless of his or her distance from the vehicle. The remote control functions also provide support in searching for a nearby public charging station.

The configuration of the remote control functions is specifically oriented to use scenarios arising in everyday traffic. For example, the driver can go shopping or eat at a restaurant while the vehicle is supplied with electrical current at a charging station. Within a very short time the driver can obtain information on the current charge status of the batteries by mobile phone. The driver can also determine how much charging time is required for the batteries to achieve sufficient energy capacity for the trip home, thus allowing other activities to be planned. Providing sufficient charge is available, the driver can also activate the heating and air conditioning during an excursion when the battery is fully charged and the vehicle is connected to the power supply. In this way a pleasant temperature can be generated inside the car within just a few minutes and in good time before setting off.

Additional trips can also be conveniently prepared using the innovative remote control functions. For example, the driver can check the charge status of the vehicle batteries and the currently available travel range while at his or her workplace or sitting in a café. This makes it quick and convenient to find out whether an additional trip can be made before driving home before the energy supply runs out. The driver gains additional flexibility in being able to search for public charging stations in the vicinity of any given location. Based on the information relayed to the mobile phone, he or she can quickly determine whether a spontaneously planned stopover can be used to charge the vehicle batteries.

Project i. With project i, the BMW Group is carrying out a unique worldwide field test in the use of electrically-powered vehicles in everyday traffic. The MINI E, of which some 600 were produced, is currently being used by private customers in the states of California, New York and New Jersey as well as at several European locations. This pilot project aims to gather important insights into user behaviour, the requirements of the vehicle concept, its specifically electric components and the energy supply infrastructure. The BMW Concept ActiveE creates a basis for the expansion and intensification of this field testing on electro-mobility, oriented towards enabling large-scale production in the future. The aim is to produce a fleet to a scale which will exceed that of the MINI E.