All-Electric Mini to be Unveiled at Los Angeles Show

The November edition of Tyres & Accessories contains this year’s batteries feature, traditionally coverage of an important yet all too often overlooked automotive component. Yet in recent times the humble battery has stepped out of the shadows, gaining recognition as more than a means of powering up a car’s accessories. The clean, green battery is again being taken seriously as a provider of motive power, and major manufacturers are taking a keen interest in its potential. The latest to do so is the BMW Group, which in late November is revealing its new electrically powered Mini.

The Mini with the batteries in place of a fuel tank will be presented to global media for the first time at the Los Angeles Auto Show on November 19. Following its debut, 500 Mini E vehicles will then be shipped to the US states of California, New York and New Jersey for testing with private and corporate customers. The cars will be delivered to customers on a one-year lease with an extension option. Monthly lease instalments will cover any required technical service including all necessary maintenance and the replacement of wearing parts. At the end of the lease, all of the automobiles belonging to the project will be returned to the BMW Group’s engineering fleet where they will be subjected to comparative tests.

The development of the Mini E, says the BMW Group, underlines its commitment to reducing fuel consumption and CO2 emissions in road traffic without compromising the driving experience. The 500 cars bound for North America will offer BMW Group the opportunity to evaluate ownership potential for vehicles supplied with an electric power supply. The group says it aims to begin series production of all-electric vehicles in the medium term as part of the company’s ‘Number ONE’ strategy.

The Mini E’s electric drive train produces a peak torque of 220 Nm, and power is delivered to the front wheels via a single-stage helical gearbox. This unique engine and transmission arrangement powers the Mini E seamlessly to 62 mph in 8.5 seconds and on to an electronically-limited top speed of 95 mph. Based on the current Mini Hatch, the car will initially be available as a two-seater. The space normally inhabited by rear passengers is reserved for the all-important lithium-ion battery.

When in use in the zero-emissions Mini, the battery unit combines high output with ample storage capacity and remarkable power output. The lithium-ion storage unit will have a maximum capacity of 35 kilowatt hours and transmit energy to the electric motor as direct current at a nominal 380 volts. The rechargeable battery is made up of 5,088 cells grouped into 48 modules. These modules are packaged into three battery elements that are compactly arranged inside the Mini E.

The energy storage unit’s basic components are based on technologies proven in power supply units for mobile phones and portable computers. The Mini E’s lithium-ion battery can be plugged into all standard power outlets. Its charge time is strongly dependent on the voltage and amperage of the electricity flowing through the grid. In the USA, users can recharge a battery that has been completely drained within a very short period of time using a wallbox that will be supplied as standard with every Mini E. The wallbox will be installed in the customer’s garage and enable higher amperage, and thus provide for extremely short charging times. Wallboxes fully recharge batteries in just two-and-a-half hours.

A full recharge draws a maximum of 28 kilowatt hours of electricity from the grid. Based on the car’s range, a kilowatt hour translates into 5.4 miles. Besides the benefit of zero-emissions driving, the Mini E thus offers significant economic advantages over a vehicle powered by a conventional internal combustion engine.

The heavy-duty battery delivers its power to an electric motor, which is mounted transversely under the Mini E’s bonnet. This power unit is able to unleash its full thrust from a dead standstill and is complemented by its dynamic deceleration potential, which is directly coupled to the accelerator pedal.

As soon as the driver releases the accelerator pedal, the electric motor acts as a generator. This results in braking force, and the power recovered from the kinetic energy is fed back to the battery. This interaction ensures a comfortable and smooth driving experience. In city traffic, some 75 per cent of all deceleration can be done without the brakes. Making substantial use of this energy regeneration feature will extend the car’s range by up to 20 per cent.

The Mini E’s 1,465 kilograms is evenly distributed across the car. Handling safety is ensured by modifications to the suspension system and the car’s Dynamic Stability Control, which is adapted due to this model’s specific wheel loads.

Production of the 500 cars will take place at the BMW Group’s Oxford and Munich sites, and is scheduled for completion before the end of 2008. Mini’s Plant Oxford will be responsible for manufacturing the entire vehicle on the standard production line, with the exception of the drive components and the lithium-ion battery. The units will then be transferred to a specially equipped manufacturing facility situated on BMW plant premises where the electric motor, battery units, performance electronics and transmission will be integrated.