EXCLUSIVE – We Speak to SGL about the use of Carbon Fiber on BMW i3 & i8

26th July 2012

We’ve discussed BMW’s breakthrough i3 and i8 vehicles many times on enlighten, often citing them as an example of innovation in the automotive market and the figurehead for the use of composite materials in the industry. That’s why we’re excited to announce that we recently met with Dr Joerg Pohlman, Managing Director of SGL Automotive Carbon Fibers, for an enlighten exclusive interview.

As a joint venture between SGL and BMW, the company is tasked with supplying the carbon fiber materials required for the auto maker’s impressive ‘i’ brand.

The BMW i3 and i8 represent real innovation in the automotive market as the use of composite materials has previously been largely limited to low volume, premium cars. As manufacturers strive to minimize vehicle weight, improve fuel efficiency and meet CO2 targets, composite materials are seen as a potential solution. However, composites bring with them a number of new engineering challenges such as crash performance, repair, recyclability, high volume industrialisation and more.

We put some of these questions to Dr Pohlman after he kindly agreed to speak with us. Take a look at the video below and let us know what you think of the BMW i range of vehicles and your view on the use of composites for high production volume vehicles.



Interview Transcript:

SGL Automotive Carbon Fibers is a joint venture formed a little more than two years ago between two companies, BMW Group, a major automotive manufacturer of course and the SGL Group which is a chemical company located in Wiesbaden, Germany focused on the carbon business.

Lightweighting Electric Vehicles
The starting point for BMW for using carbon fiber was ‘project I’ which started in 2008. SGL Automotive Carbon Fibers was formed as joint venture specifically for the purpose of supplying the BMW Group with the necessary carbon fiber for i3, the Megacity vehicle, and i8 the sports car. The use of carbon fiber is a crucial element in this strategy, lightweighting this electric vehicle and countering the additional weight that comes from the lithium-ion batteries.

Quite obviously, carbon fiber is a very expensive material, however in using carbon fiber to counter the additional weight of batteries in electric vehicles still makes a positive business case. However, BMW is also interested in using carbon fiber in other vehicles and when looking at the overall cost structure there are quite some advantage in using composite materials and carbon fiber. For example in traditional car manufacturing you need welding robots, you don’t need those when you glue composite parts together. Another example is that you do not need additional surface treatment because composite materials do not suffer from corrosion. 



Composite Crash Performance
Using carbon fiber and composite materials in car construction has huge advantages also for the passengers in a crash situation. You are certainly aware that if you use metals, these metals are bent in the case of an accident and that’s how the energy is absorbed. In the case of using composite materials this works in a different way in that the matrix that is the fiber in conjunction with the resin actually crashes and breaks and that’s how the energy is absorbed. However, you do not have a dent in the vehicle thus leading to a better protection of the passengers inside the vehicle.

BMW certainly learned a lot using carbon fiber over the last years but there were only single parts being used such as the BMW M3 Coup roof made from carbon fiber. Accordingly there is a lot to be learned and a lot of information is being gathered in the construction of the i3 and the i8. I think there is a very steep learning curve right now at BMW with respect to crash simulation results for example, also the repair technology which is also an important factor.

Green Energy Production
The joint venture was formed to guarantee the supply and since we need about 10% of the world’s market capacity it was clear that we would need a new facility. One important aspect of the production strategy was from the start to base the manufacturing of carbon fiber on sustainable energy. Manufacturing carbon fiber is a very energy intensive production, that’s why we said from the start that if we do this we need renewable energy and we decided in favor of hydro-power because the sun doesn’t always shine, the wind doesn’t always blow but we need to run our factory 24 hours a day, 365 days a year. That’s why we chose the location of Washington State because this location guarantees access to hydro-power at a very, very competitive rate. The second location was built up in Wackersdorf, 160km North of Munich to transfer this carbon fiber into textile fabrics which are then used to manufacture parts in the BMW plant.

Carbon Fiber Recycling
An important aspect of our production system is our recycling technology that we developed for this purpose. The ways this works is that we get the cut offs from the production of car parts in the SGL and BMW plants and we turn them into a fleece that we can then use again to manufacture car parts which are being used for example in the i3 or i8. Likewise we will use carbon fiber that we regain from real car parts that we will get back at the end of the lifecycle of an i3 or an i8 or other cars that use carbon fiber and the re-used carbon fiber can be used again to make car parts.

Innovation is of course a very important factor in the automotive industry and a key element in being able to distinguish one car from another. BMW is aware of this and the joint venture wishes to contribute to this of course in securing the carbon fiber supply but also by coming up with even more exciting composite elements that can be used in future projects.

Future Outlook
Certainly when looking at the competitive environment, one can say BMW together with its partners SGL and the joint venture is really quite ahead of the competitive and I would say when asked that this advantage is certainly around 3-5 years.

The joint venture certainly believes in the future of this material. We have looked at many different technologies and we are currently improving the existing technologies but we are looking into many new ways of creating exciting materials that we can offer our customer, BMW, and I’m sure we will see a lot more composite components in future projects from the BMW Group.