"This automotive concept uses a new architecture which showcases all of its new possibilities and potential. It is the world's first premium electric vehicle." - Andreas Feist, Head of vehicle project BMW i3.
The Life module conjures up a feeling of space inside the car more generous than even the latest conversion vehicles can offer. Select materials lend the open and airy cabin a lounge-like character. The use of renewable raw materials is another defining characteristic of the interior, offering passengers a further means of "experiencing" the sustainability of the vehicle. Elements of the instrument panel and door panelling are visibly made from natural fibres, while the naturally tanned leather of the seats creates a lounge-style ambience. Together, these materials provide an appealing contrast to the clear, "floating" forms of the instrument panel and door elements, and lend the interior a strikingly modern feel. With the drive components located in the Drive module, there is no centre tunnel running through the passenger compartment. This allows the two front and two rear seats to be connected with each other by a continuous seat surface, which allows for ease of entry and exit via the front passenger side of the car and means you can park up close to walls, for example. With four seats, wide-opening opposing "coach" doors, boot capacity of around 200 litres and an additional functional compartment in the front, the BMW i3 Concept is neatly equipped for the demands of everyday use.
However, the electric motor developed by BMW and the optimised lightweight design of the LifeDrive architecture cannot take all the credit for imbuing the car with such efficiency and enabling it to travel such long distances on each charge. Indeed, the ability of the car to recoup energy while on the move and special range-extending functions, such as ECO PRO mode, also add miles to the clock. With ECO PRO mode activated, all the vehicle functions operate with maximum efficiency. For example, the accelerator mapping is tweaked to limit the output summoned when the driver flexes his right foot, and the climate control functions also use as little energy as possible. Added to which, sophisticated aerodynamics and slim, low rolling resistance wheels minimise resistance to the car's forward progress and maximise its range.
Innovative connectivity functions create a seamless connection between the BMW i3 Concept and its customers' lives outside the car. Remote functions accessible via a smartphone enable owners to find their vehicles, flag up nearby charging stations, allow battery charging and preconditioning at the touch of a button and supply information on the current status of the vehicle. Meanwhile, intelligent assistance systems ease the stress on drivers in monotonous city driving situations and allow them to arrive at their destination more safely and in a more relaxed state of mind.
The LifeDrive architecture
Both the BMW i3 Concept and the BMW i8 Concept have been designed around the innovative LifeDrive architecture. However, the geometric implementation of the concept differs in the two models, having been adapted to suit their different usages. The BMW i3 Concept features a horizontal-split variant of the LifeDrive concept optimised to accommodate the car's electric drive system. Here, the Drive module provides the solid foundations for the Life cell, which is simply mounted on top. The driving element of the Drive module's functional design is the battery, which is made as large as possible to give the car better range. Bearing in mind the size of the BMW i3 Concept's battery, the most space-efficient place to store it was in the car's underfloor section. There, it occupies the whole of the module's central section, giving the car optimum weight distribution and a low centre of gravity and therefore enhancing its dynamics. The battery is penned in by aluminium profiles, which protect it from external impacts. Crash-active structures in front and behind it provide the necessary energy absorption in the event of a front- or rear-end collision. The electric drive system is, as a whole, much more compact than a comparable combustion engine, cleverly accommodating the electric motor, gear assembly and drive electronics - in space-saving fashion - within a small area over the driven rear axle. The BMW i3 Concept therefore features the optimum LifeDrive architecture configuration for a purely electric vehicle.
The chassis of the BMW i3 Concept is also ideal for city driving. Its enviably small turning circle and direct steering responses are a recipe for outstanding agility, notably at low speeds. Rear-wheel drive allows the front axle to remain free from drive forces and therefore to carry out its steering function to optimum effect. These elements team up with the electric motor - whose impressive torque from a standstill provides exceptional traction - to produce extremely dynamic handling characteristics.
The spacious Life module of the BMW i3 Concept allows the vehicle's interior to boast a totally new design. The integration of all the drive components within the Drive module removes the need for a centre tunnel bisecting the interior, through which power would previously have been transferred to the rear wheels. The BMW i3 Concept therefore offers significantly more interior space than other vehicles with the same wheelbase and - through solutions such as a full-width seat bench - also allows the interior to be adapted extremely effectively to the needs of urban mobility. Added to which, a pair of opposing doors and the omission of B-pillars provide a large entry area for passengers - and a generous view into the cutting-edge interior for admiring eyes. The BMW i3 Concept offers comfortable accommodation for four passengers and, with around 200 litres of boot space, room for their luggage as well. Up front, underneath what would normally be the bonnet, the Life module gives the BMW i3 Concept a separate luggage area with space for the charging cable and other items passengers would rather not carry in the passenger compartment.
The electric motor of the BMW i3 Concept is designed primarily for operation in an urban environment. Already tested in a pre-production version in the BMW ActiveE, the version of this permanently excited hybrid synchronous motor which will be used in the BMW i3 Concept has undergone further optimisation in terms of weight and driveability. It develops 125 kW/170 hp, with peak torque of 250 Nm (184 lb-ft). Typically of an electric motor, maximum torque is developed from standstill, in contrast to an internal combustion engine where torque increases with engine rpm. This makes the BMW i3 Concept highly agile and provides impressive acceleration. The BMW i3 Concept accomplishes 0-60 km/h (37 mph) in under four seconds and 0-100 km/h (62 mph) in under eight seconds.
At the same time the abundant torque is delivered over a very large rpm range, resulting in very smooth power delivery. The single-speed gearbox provides optimal power transmission to the rear wheels and accelerates the BMW i3 Concept to an electronically governed 150 km/h (93 mph) without the loss of power typically associated with having to shift gears. The speed governor cuts in at this point in the interests of efficiency: going even faster would result in very high energy consumption, which would unnecessarily restrict the driving range. The motor is located directly above the drive axle, for optimal and typical BMW rear-wheel-drive handling characteristics.
But impressive, instantaneous, response is not the only distinctive aspect about the driving experience in the BMW i3 Concept. Another is the dual accelerator/decelerator function of the accelerator pedal. After the driver eases up on the accelerator, the electric motor acts as a generator, converting the kinetic energy into electricity which is then fed back into the battery. Energy recuperation generates a braking effect which makes a significant contribution to vehicle deceleration. Around town, approximately 75 per cent of all braking operations can be performed in this way, i.e. without using the brake pedal at all. Intensive use of this energy recuperation function of the electric motor can increase the driving range by up to 20 per cent. Only when the driver's braking request exceeds a given level is the conventional brake system of the BMW i3 Concept engaged as well.
A coasting facility makes this unique "single-pedal control" of acceleration and braking using just the accelerator even more user-friendly. The BMW i3 Concept features a distinct "neutral" position of the accelerator pedal, i.e. rather than switching straight to recuperation when the driver eases off the pedal, the electric motor's zero torque control keeps the drive train disconnected as long as the pedal is in this position. The vehicle now coasts without consuming power, driven by its own kinetic energy. Used as part of a proactive driving style, this coasting mode is a very user-friendly way of increasing the driving range even further.
Compact and powerful - the electric motor
The electric motor of the BMW i3 Concept not only offers attractive driveability, it also has a very high power-to-size ratio. This is partly explained by the fact that electric motors typically achieve over 90 per cent energy efficiency. This means that a smaller electric motor can produce the same power output as a larger internal combustion engine. Due to its compact size, the electric motor used in the BMW i3 Concept can be optimally integrated into the vehicle architecture. The permanently excited hybrid synchronous electric motor and the power electronics of the BMW i3 Concept were developed entirely in-house, and boast very high efficiency, optimised power delivery and compact design. As mentioned, the innovative nature of the electric motor is particularly evident in the favourable power-to-size ratio. As a result of continuous development and refinement, the space requirements of the electric motor used in the BMW i3 Concept have been reduced by 40 per cent compared with the motor used in the MINI E. This compact drive unit is mounted over the rear axle, together with the power electronics, transmission and differential, causing no loss of interior space.
The power needed to drive the vehicle and to operate all other vehicle functions is supplied by specially developed lithium-ion battery cells. The BMW i3 Concept's battery system has undergone detailed optimisation which significantly reduces the extent to which external factors can influence the vehicle's power and driving range. An integrated liquid cooling system keeps the battery at its optimal operating temperature at all times, which helps to significantly boost the performance and life expectancy of the cells. The climate/heating system cools the fluid circulating in the battery housing via a heat exchanger.
If necessary, in winter, this fluid can also be heated in order to bring the battery up to its optimal operating temperature of around 20 degrees Celsius. These precautions ensure that power and torque remain constant throughout most of the battery's charge range and make the system significantly less sensitive to extreme external temperatures. The battery can be fully recharged in six hours at a standard power socket. If a high-speed charger is used, an 80 per cent charge can be achieved in just one hour.
Range Extender increases the driving range
As the MINI E field tests showed, a driving range of 120 to 150 kilometres (74 to 93 miles) was sufficient to meet 90 per cent of the mobility requirements of the pilot users. However, some customers want a longer driving range, or want their vehicle to be as flexible as possible. The BMW i3 Concept therefore offers an optional Range Extender, the REx, which allows the electric driving range to be increased. REx, a small, very smooth-running and quiet petrol engine, drives a generator which maintains the battery charge level and therefore extends the range of the electric motor. As soon as the battery charge reaches a critical level, REx supplies the necessary energy to get the driver the rest of the way to his destination. In a sense, therefore, the Range Extender is like having a reserve fuel can on board.
The very compact size of the electric motor used in the BMW i3 Concept means there is room left over to accommodate REx and its attached generator over the rear axle, alongside the drive components. The petrol engine complies with the SULEV standard, currently the strictest emissions standard for internal combustion engines. To reduce fuel consumption to a minimum, REx also features such functions as Automatic Start-Stop and other intelligent operating strategies.
BMW i3 Concept - compact, agile, sustainable
The design of the BMW i3 Concept reveals the car's qualities the first time you set eyes on it. The BMW i3 Concept represents the dynamic interpretation of an impressively practical vehicle.
The proportions - dynamic, compact
Agile and compact proportions showcase the agility of the BMW i3 Concept and the dynamic prowess of its electric drive system. The stylistic lines within the car's proportions provide additional emphasis here. From the side view, a number of elements combine to create a dynamic wedge shape, giving the car the feeling of pushing forward before it even turns a wheel. The generously-sized greenhouse tapers towards the rear and, together with the rearwards-rising door sills, emphasises the car's dynamic inclinations. Above the greenhouse, the "stream flow" - a dynamic stroke descending from the roof into the C-pillar - adds further urgency to the forward-surging stance. From the outside, a flowing silhouette and long wheelbase hint at the extraordinarily generous levels of space on offer in the interior, while short front and rear overhangs make parking in tight spaces that much easier. Practicality gets another boost from the "coach doors", whose opposing construction creates a fresh new way of accessing the wide-open spaces of the interior.
"The design reveals the driving pleasure on offer with electromobility. And you can add to that a large and practical interior." - Benoit Jacob, Head of BMW i Design Team
Extensive glass surfaces and black elements like the window surrounds and door sills give the vehicle a feeling of lightness and, together with the exposed carbon structures, draw attention to its low weight. At the same time, the lack of B-pillars ensures a seamless transition between the two doors. The result is a large, homogeneous glass surface, which gives the car's flanks a very transparent look. Large, narrow 19-inch wheels add further impact to the dynamic side profile of the BMW i3 Concept. Their slim construction allows them to reduce the car's drag and rolling resistance, and to avoid encroaching into the interior. And that means more space for the passengers.
- Length: 3845 mm
- Height: 1537 mm
- Width: 2011 mm
- Wheelbase: 2570 mm
- No. of seats: 4
- Kerb weight: 1250 kg
- Output: 125 kW (250 Nm)
- Top speed: 150 km/h (93 mph)
- 0-60 km/h (0-37 mph): 3.9 s
- 0-100 km/h (0-62 mph): 7.9 s
- 80-120 km/h (50-75 mph): 6.0 s
- Electric range
- Everyday range: 130-160 km (80-100 miles)
- FTP72 cycle: 225 km (140 miles)
- Battery charge time
- Standard: 6 h for 100% charge
- Optional: 1 h for 80% charge