ThinKing July 2015: Light e-bike with revolutionary propulsion –



CarboFibretec teams up with other SMEs to adapt Transrapid technology for e-bikes. The battery and drive are now “invisibly” integrated in the frame for the first time

The futuristic-looking e-bike Velocité is something quite special. CarboFibretec engineers have worked with SME partners over a period of several years to develop a unique solution: hiding the batteries, electric motor and coil in light carbon bicycle frames E-bike with revolutionary new power transmission. It uses Transrapid technology.

The Development Agency for Lightweighting Baden-Württemberg presents this innovative technology in the July issue of ThinKing. Leichtbau BW GmbH uses this label to showcase excellent lightweight technology products or services from Baden-Württemberg.

The Velocité’s technical data speak for themselves: at just 14 kilograms the prototype is substantially lighter than conventional e-bikes. This weight advantage has a positive impact on its range. The innovative and efficient electric motor technology enables the bicycle to accelerate dynamically up to 45 km/h. The power flow is generated between 180 magnet platelets on the rear wheel and a so-called stator integrated in the frame. “That’s the Transrapid being transferred to the bicycle,” says CarboFibretec Managing Director Thomas Leschik.

The energy used to power the Velocité comes from a battery in the down tube which uses alternative cell technology and which is invisible at first sight. One advantage of the carbon frame apart from its high-quality look, lightness and high stiffness is that the material does not shield the magnetic flux – if it did, it would be technically impossible to integrate the magnet and coil.

Speeds of up to 120 km/h possible

The Velocité’s patented rim motor weighs around three kilograms and has power of 500 watts. Comparable products with the same power weigh almost twice as much. The power-to-weight ratio for the rim motor is 250 watts per kilogram. “The bike can consequently accelerate from a resting position much faster,” explains Leschik. The new technology transfers the power flow directly from the motor to the road; a gearbox is no longer needed. The 500 watt model reached a speed on 120 km/h on the test stand.

The Velocité is a sporting means of transport which could easily tap into a completely new target group when it is launched on the market. Bike commuters in cities with particular expectations of design and technology, for example. The wheelbase is more like that of a racing bike. Conventional e-bikes “are a bit bus-like in comparison,” comments engineer Leschik. He believes that the Velocité's properties have the potential for new mobility concepts - in the megacities of Asia, for example.

One highlight, which will almost certainly appeal to the envisaged target group, is the option of integrating a smartphone in the bike. A separate holder in the handlebar has been planned for this purpose. Apps can then be used during travel to check tyre pressure or brake wear. “You can network with the bike,” says Leschik.

The start-up project, which was launched in 2010, has been supported by the Federal Ministry of Education and Research (BMBF) to the tune of 2.5 million euros. Seven companies and research institutions with around 60 staff members participated in the consortium. CarboFibretec lead managed the development of the frame and bicycle wheel concept as well as the design and function of the electric motor. Researchers also made a substantial contribution to the high-tech demonstrator: The Fraunhofer Institute for Transportation and Infrastructure Systems (IVI) and the Fraunhofer Institute for Silicon Technology (ISIT) were responsible for energy management and the chip design for power electronics and cell technology.

With industry 4.0 in mind, Leschik believes that “Transrapid” technology could also be used in other fields such as construction machinery, mountain railways or robots as well. “Basically, anywhere where light transverse flux machines have to be operated.” The Managing Director also thinks that other industries could also be interested in the component monitoring system, such as the bike-mounted smartphone system.

The technology is already available. All that is needed is an investor who can support the idea until it is commercially viable. “We need a partner who can finish the development of Velocité with us,” says engineer Leschik. He thinks it will take another two years to establish the new drive concept in the burgeoning e-bike market.

About CarboFibretec

CarboFibretec was launched in 2001 with pioneers from the previous Dornier-Luft-und-Raumfahrttechnik. 14 years later the company is a leading innovator for carbon products and lightweight technology. A team of around 100 produces custom-tailored carbon solutions in Friedrichshafen. The company, which operates on the shores of Lake Constance, has one of the most highly-coveted certifications for the production of aerospace components: its winding technology with highly rigid carbon fibers, for example, is one of the company’s specialisms. As well as individual solutions for customers in the mechanical engineering, medical technology and agricultural sectors, the company also develops and produces series products for the premium Lightweight carbon wheel brand. CarboFibretec has also played a key role in avantgardistic architectural projects, such as the BMW Guggenheim Lab and the Rietberg Museum.