BMW i3 built to close the loop
The new electric car from BMW is a zero emission vehicle that has been manufactured with sustainability at its heart.
Launched with great fanfare at the end of July, the BMW i3 is the company’s first model in its new i series of cars that aims to find solutions for vehicles in a world of climate change, dwindling resources and increasing urbanisation.
The i3 is the first BMW car that runs on electric power alone, with a range of 130 -160km (81-99 miles) in everyday driving conditions when fully charged.
Due to be commercially available from the end of 2013, the i3’s architecture is based on an aluminium module that encompasses the powertrain, battery and chassis with a passenger cell made of a carbon-fibre-reinforced plastic (CFRP).
This is the first time, according to BMW, that this lightweight, durable and crash-safe CFRP has been used on this scale in volume car production.
“From the start, we redesigned our entire development and production processes,” says BMW chairman Norbert Reithofer. “The i3 is purpose-built around an electric powertrain to serve the needs of our megacity customers.
“With every step of the way from development, to production, to after-sales, the BMW i3 sets new benchmarks in sustainable mobility. In the brand-new architecture, we use carbon fibre for the passenger cell - a first in high-volume car production.
“Our expertise in manufacturing with this material makes the passenger cell extremely strong and light weight. We produce the carbon fibre material using hydroelectric power. And we build the BMW i3 using wind power.
“Our innovative production methods are also unique. The carbon fibre components are bonded together in a fully automated process. The bonding techniques we have developed in-house are setting new industry standards.
“In response to global trends such as urbanisation and increasing carbon emissions, sustainability is an important part of a modern, urban lifestyle.”
The main benefit of the CFRP is that it reduces the weight of the vehicle, and has been typically used on high-cost sports cars to provide additional speed.
In this case, the use of CFRP for the passenger cell and the aluminium module cancels out the extra weight of the lithium-ion battery that powers the car.
A robust outer plastic skin is attached to the CFRP compartment to allow freedom for design suchbody colours.
Around 25 per cent, by weight, of the plastic used in the interior of the car has been replaced with recycled materials or renewable raw materials.This includes leather and wood that come from sustainable sources.
In the course of the research process for the i-series cars, BMW developed a world-first commercial-grade recycling concept for CFRP components, body components and segragated production waste. Using various methods, high grade materials from the production process and even from damaged or end-of-life vehicles are reused, and are either placed back into the vehicle production process or for other uses in other industries.
In the recycling process, a distinction is drawn between dry recycling of non-resin-impregnated carbon fibre and wet recycling of resin-impregnated components. Dry carbon offcuts from the production process can be reprocessed into high-grade non-woven fabrics and reused in the production manufacturing cycle. Indeed, this secondary material already accounts for around 10 per cent of the carbon fibre used in the i3.
For the recycling of resin-impregnated carbon-fibres, CFRP is first separated industrially from the other plastics and processed in a pyrolysis facility.
This process heat from the breakdown of resins is used to separated the undamaged carbon fibres. These fibres can then be used to manufacture new components, thereby reducing the new consumption of fibre. For example, the rear seat pan is made from this recycled carbon fibre. While the short or cut fibres can be used for in the textiles or electronics industries.