bMW’s electric charge
BMW is not left behind in the race to develop an electric car for the masses.
WITH a little whir, the little model leapt forward like a race car the instant I floored the accelerator. The sudden burst of speed from the powerful torque nearly wrenched the steering wheel out of my grasp, causing the vehicle to swerve dangerously towards the opposite lane, and forcing me to grip the wheel tighter to bring it under control.
Fortunately, that was the only scare I had while testing the Mini E in Munich, Germany. Suffice it to say, I learnt my lesson after that – don’t underestimate the power of an electric car.
The Mini E is an electric car with no engine or gas tank. It runs solely on an electric powertrain and a battery. Fully charged, it can go up to 156km and achieve a top speed of 154km/h.
The Mini E is BMW Group’s first step towards their vision of producing a fully electric Megacity Vehicle by the year 2013. The megacity vehicle is BMW’s vision for the future – a future where most of the world’s population would be living in megacities and where automobiles run on electricity and have zero carbon emissions. It is a future where eco-friendly mobility solutions are imperative if we are to prevent the planet from deteriorating further, even if this means a wholesale reappraisal of automobile design as we know it.
During the BMW Innovation Days: Mobility Of The Future workshop in June at BMW Group’s headquarters in Munich, journalists were taken through a series of presentations that detailed exactly how BMW planned to go about reinventing the automobile.
In late 2007, the German automobile manufacturer launched Project I, an initiative to drive the company forward via fresh ideas and projects that achieve sustainability from the very first supplier, at the beginning of the production process, through to the recycling of components at the end of the vehicle’s life cycle.
Spearheaded by Project I head of development Peter Ratz, a think tank consisting of experts and “outside-the-box” thinkers from throughout the company was created, and they were allowed and encouraged to work along unconventional lines, transcending the company’s existing structures.
Project I’s ultimate objective is to create the megacity vehicle, an automobile that combines eco-friendliness (such as zeroemission operation) with modern urban mobility requirements.
“Half of the world’s population already lives in cities and the numbers are rising daily,” said Ratz. “Therefore, mobility for the future requires a new balance between global requirements and individual needs and above all, sustainable mobility in urban areas.”
From the outset, it was obvious that the megacity vehicle should be powered by electricity. After all, the benefitsof an e-vehicle are numerous, beginning from the elimination of fossil fuels to zero climate-harming emissions during the journey.
Unfortunately, there is one problem: an electric car needs to be powered by a battery and that battery has to be really big if it is to match the range of a conventional combustion engine.
Up to now, a battery is able to store only a limited amount of energy, resulting in a limited driving range. BMW reckons that research efforts over the next few years will improve the technology of batteries and enable greater ranges. However, rather than making the battery for its e-vehicle bigger and heavier to accommodate better range, BMW decided to extend the range through other measures, including radically altering the architecture of the car.
One of these innovations is the lightweight design of the vehicle’s main architecture. Called the LifeDrive concept, this new approach acombines the requirements of electrical mobility into an impact-resistant structure. LifeDrive consists of two independent modules. The Drive module – the chassis – forms the solid foundation of the vehicle and integrates the battery, drive system and structural and basic crash functions into a single construction. For instance, the battery is mounted in the under-body section of the car to give it the best possible protection since this is the area that suffers the least deformation in the event of a crash.
The Life module is a high-strength and extremely lightweight passenger cell made from carbon fibre-reinforced plastic (CFRP) which is a unique composite material that consists of a carbon fibre that is embedded in a plastic matrix (resin). Forecasted to replace the steel used in today’s cars, the use of CFRP on such a scale is unprecedented.
At first, it was hard to believe that the thread-like fibre we were shown could be moulded into a car frame strong enough to withstand a head-on collision but it all became clear when we learnt how this is accomplished. First, the fibre is manufactured into textiles which are then impregnated with resin and moulded into shape. With the fibre as the load carrier, and the resin supporting the matrix, the resultant structure is highstrength and lightweight at the same time. It is also 50% lighter than steel and is resistant to rust and fatigue.
The Mini E, BMW Group’s first ever 100% electric vehicle; 600 of these were produced and field tested by consumers all over the world to collect feedback on the requirements of a future Megacity Vehicle. A piece of textile made from carbon fibre, and ready to be made into carbon fibre-reinforced plastic (CFRP) that can be moulded into a car frame strong enough to withstand a head-on collision.
The material is safe too. While metal vehicle frames require large crumple zones, special deformation elements in the CFRP structure allow a maximum amount of energy to be absorbed within a minimum space, keeping it away from the passenger.
For further proof of the safe and light properties of CFRP, look no further than Formula One race cars, which use it for their racer cockpits. It is also being used in the aviation industry and has been incorporated into BMW vehicles. Another advantage of CFRP is that it can be tailored for different uses; this is more efficient than shaping an unformed material like steel. Cut-offs and leftovers are chipped and turned into fibre that can be refleeced into the textile again.
CFRP is not without disadvantages though. “The cost (of manufacturing) is one, as is the current complexity of the process. Also, we have yet to know exactly what kinds of loads it can withstand,” said Ratz.
Mobile and fun
With these basic concepts and processes in Engineers at BMW working on the LifeDrive concept passenger cell, which is made out of CFRP.
place, BMW revealed the Mini E as Project I’s first e-mobility-enabling project in 2008. Six hundred units of the car have been testdriven since mid-2009 in the United States, Britain and Germany. The little car has not only set new technical standards with an average driving range of 150km in everyday operation and maximum power of 204hp, but is also seen as a valuable first step towards emission-free automobiles.
The initial results of the trials have been encouraging. More than 90% of participants reckoned that the average 150km driving range did not restrict their routine mobility and they had no problems with the constant charging of the vehicle.
The data did show, however, that a successful megacity vehicle would need a slightly longer driving range and more space. This led to BMW producing its first all-electric vehicle in late 2009, the BMW ActiveE concept car.
Relying on feedback from the Mini E trials, it developed a new electric motor supported by a new lithium-ion battery which gives a