Innovative pure-electric testbed is basis for i3 production car
By Will Dron on October 30, 2011 9:51 AM
BMW has seen the future of motoring and it places plug-in vehicles front and centre. The company launched its 'BMW i' programme in July this year with a focus on sustainability, taking “a holistic approach with purpose-built vehicle concepts for electric mobility.” Basically, the idea is to be greener at every stage of the vehicle’s life, from design via production to dismantling and recycling, but not to lose a premium feel and driving pleasure. Sounds good to us.
In 2013 we will see the first production pure-electric car from the BMW i programme, the i3 hatchback. That will be followed in 2013 by the beautiful plug-in hybrid i8 sportscar. With a combined 350bhp at its disposal from the petrol and electric motors, drive to all four wheels and lightweight carbon fibre construction, the i8 should be as good to drive as it is to look at.
Why carbon fibre?
Carbon fibre is the key to BMW’s electric strategy. Electric cars are heavy, because batteries are heavy. Removing the big iron block and pistons that sits under the bonnet of a ‘traditional’ car as well as the fuel tank takes a chunk of weight away, but adding an electric drivetrain adds decidedly more heft. A Ford Focus Electric, for example, weighs in at 1,674kg, some 400kg heavier than the base petrol model.
The BMW i3's carbon fibre shell undergoing testing
By replacing much of the i3 and i8’s metal construction with carbon fibre (the entire passenger compartment, which sits on top of the flat chassis), BMW is compensating for the battery’s extra weight.
So why hasn’t anyone done this before? Well, cost is the main barrier – carbon fibre has until now been a very expensive material to work with. It’s used extensively in the aeronautical industry, and Formula One cars employ large quantities of the stuff, but at very great expense.
BMW’s solution is bold but not revolutionary – simply churn the stuff out in your own plant in massive quantities, thereby achieving economies of scale. The company’s first carbon fibre plant, built in conjunction with SGL Automotive Carbon Fibres, now produces its own carbon fibre sheets at Moses Lake, USA.
Paving the way
The i3 and i8 are being preceded by two slightly less groundbreaking vehicles - the MINI E (MINI being owned by BMW) and the BMW ActiveE are adapted from the current MINI Cooper and BMW 1 Series respectively. Both have racked up a great many miles of real-world experience in trials, with many more still to go; no other car company is running electric vehicle tests on this scale right now.
"No other car company is running electric vehicle tests on this scale right now"
Due to the fact that most of the electric innards of the MINI E are purchased off-the-peg by BMW from external suppliers, the MINI’s field trials have been mainly focused on how people use electric cars (where they charge, when the charge, how far they drive, etc. – you can read about the results of the UK trial here).
The BMW ActiveE, however, is a whole different kettle of electric eels. Every component is BMW designed and built, with the exception of the battery cells, and so the focus of the trials is very much on technical learnings about the drivetrain, with the results being fed directly into the development of the i3. In that regard, the ActiveE is even more important than the MINI E, and an invitation to join BMW in its hometown of Munich to try out the car was something we weren’t going to miss.
The car packs a liquid-cooled 32kWh lithium ion battery (8kWh larger than the Nissan LEAF) split into three parts that allow a 50:50 front-rear weight distribution. Charging takes up to 12 hours from the UK domestic socket, but that’s reduced to four or five hours on a 32A fast charge. Range is a claimed 100 miles.
Under the skin of the BMW ActiveE
With the ActiveE, weight saving and driving dynamics are not the order of the day; it’s the robustness, performance and efficiency of the motor, battery and electronic control unit that the company is focussed on. To illustrate this point, the ActiveE weighs in at a hefty 1,815kg while the carbon-fibre i3 Concept car tips the scales at a much more acceptable 1,250kg.
So a test drive of the ActiveE is a curious thing – matters that are usually of key importance such as handling, acceleration and braking are largely irrelevant, as is the quality of the interior and available luggage space as the ActiveE itself will never be made available to the general public.
The view from behind the wheel
While we’re no stranger to electric cars at TheChargingPoint.com, the site of a barn-sized room full of experimental ActiveEs is exciting. It drives home the scale of BMW’s ambitions.
We’re handed the key to one of the cars, given a quick overview from an engineer, although driving an electric car is seriously uncomplicated – switch on, put in ‘drive’, take off handbrake, push down on right-hand pedal and we’re off.
The ActiveE's iDrive system
The BMW ActiveE uses the same iDrive system, which controls the onboard computer, as the 1 Series. We have satellite navigation and most of the usual displays, plus three extras – energy consumption history, energy flow around the car and current battery state. Directly in front you get two large dials rather than the digital displays common in electric vehicles, which we at TheChargingPoint.com prefer – analogue dials are simple to read and fuss free. On the ActiveE you’re shown speed and ‘eDrive’ state (if you’re accelerating the needle moves to the right, decelerating and it moves to the left, indicating regen - that is to say, ‘regenerative braking’ or the way the car recaptures energy and funnels it back into the battery while slowing down). At the bottom of the right-hand dial is the battery level gauge – simple.
Inside the ActiveE you'll find BMW's not dropped its standards just because this is a testbed vehicle
Our route takes us on a 35km route through Munich, with a mix of A-roads and inner-city driving. Of course, the quality of the 1 Series chassis means the ActiveE is supremely quiet and refined, but the most apparent trait of the car is the strength of its regen; lifting off the accelerator gives an extreme amount of regenerative braking, much more noticeable than almost any other electric vehicle out there (other than, perhaps, the MINI E). It’s quite possible to control the speed of the BMW with the accelerator pedal alone, even bringing it to a complete stop at lights – the brake pedal is rendered virtually redundant. The effect is so strong that we were concerned following motorists might run into the back of our car, but we were later reassured that the brake lights do illuminate when lifting off. The system is designed to recover as much energy as possible, and after a few minutes you quickly get a feel for efficient driving technique, delicately accelerating and gently lifting off.
"The quality of the 1 Series chassis means the ActiveE is supremely quiet and refined, but the most apparent trait of the car is the strength of its regen"
Of course, we sampled the car’s performance, too, and the power on offer is impressive. The ActiveE’s claimed sprint to 62mph time is nine seconds and a quick punch from 25mph to 62mph is impressive, the 127kW (170bhp) electric motor delivering maximum torque throughout the rev range.
Unfortunately the fun didn’t last on our outing. Halfway round the test route a warning message flashed up on screen saying there was a drivetrain malfunction and that we should pull over and stop safely. Within a few seconds there was no drive power at all, and the car ground to a halt. BMW technicians were quickly on the scene to investigate, later reporting back that there was an AC/DC inverter glitch causing the 12-volt battery not to charge, leading to a system shutdown. According to BMW this was the first time they had seen this fault but engineers said it can be corrected with a software update.
A BMW ActiveE on the move, which is a normal state of affairs
To be completely fair and above board, a red battery symbol was displayed on the dash from as early on the drive as we can remember – almost certainly from the off – so it was interpreted as a normal symbol differentiating the ActiveE from the standard 1 Series. Apparently not. It should also be noted that none of the other 30 or so ActiveEs being driven that day developed a fault.
Just 1,100 examples will be produced at BMW’s Leipzig plant for trials in the USA, Europe and China. Of those 1,100 vehicles, 160 will be shipped to the United Kingdom, but they have a special assignment – they will form part of BMW’s official 2012 London Olympic Games fleet along with the 40 MINI Es (now all held by EDF Energy) in a total fleet of 4,000 BMW vehicles (including petrol and diesel). The chance to get Usain Bolt in a BMW electric vehicle is a real coup, and the profile of EVs during the Games will undoubtedly receive a much-needed boost.
Aside from helping to make the 2012 London Games the most sustainable of all time, the use of electric vehicles at the Olympics is of particular relevance to BMW; the company’s first ever pure-electric vehicle – the 1602e – was created specifically for the 1972 Munich Games. “Back in 1972, it joined the marathon runners at the Olympic Games in Munich,” BMW Chairman Dr. Norbert Reithofer said recently. “Sustainable mobility is a marathon as well. However, we are in the race — and clearly focused on the road ahead.”