Daimler and BASF jointly develop smart forvision concept electric vehicle; energy efficiency, temperature management and lightweight design
|Hexagonal, transparent solar cells on the roof of the smart forvision. Click to enlarge.|
Daimler and BASF have developed a new joint concept electric vehicle that combines both companies’ ideas for holistic electric mobility. The smart forvision, which will have its world premiere at the 64th International Motor Show in Frankfurt, was developed with a special emphasis on energy efficiency, temperature management and lightweight design.
The smart forvision is intended to showcase technologies for electric mobility of the future. Some of the materials and technologies are still at a laboratory stage, while others have a realistic chance of entering series production. The use of advanced materials and technologies allowed new concepts to be implemented in the electric car that generate power as well as save it. The resulting increase in range contributes to further improving the performance and economy of electric vehicles—the partners estimate that with maximum energy efficiency, intelligent temperature management and consistent lightweight construction it is possible to increase EV range by up to 20%.
Energy efficiency. Transparent solar cells covering the entire roof surface create the first light-transmitting roof that also generates energy. The hexagonal cells are based on organic dyes embedded in a sandwich roof. The transparent dyes of the solar cells are light-activated. Even in diffused light and poor light conditions they generate enough energy to power the multimedia components and the three fans that assist with climate management in the vehicle interior.
If the vehicle is standing in the sun the ventilation is permanently operated with the help of these solar cells, keeping the car cool. This new photovoltaic technology opens up further efficiency potential and the energy generated can be used for further applications in the car.
There is an additional new feature under the solar cells: transparent OLEDs (organic light-emitting diodes) illuminate the vehicle interior when the door is opened or a button pressed. When switched off they allow for a clear view outside. This results in a glass roof effect during the daytime, while the areas are illuminated without any dazzle at night. With a free choice of colors, the new OLEDs offer more design freedom; they also consume less than half as much energy as conventional energy-saving lamps.
Lightweight design. The smart forvision features the first all-plastic wheel suitable for high-volume production. In its current development status, the wheel developed by BASF from a new high-performance material (Ultramid Structure) results in a considerable weight saving of three kilograms per wheel. Unlike conventional polyamide composite materials, this new plastic has long reinforcing fibers which improve its mechanical properties. The result: excellent thermal and chemical stability, dynamic strength, toughness and good continuous operating characteristics.
First intensive product tests at smart show the performance capability of the all-plastic wheel and confirm the potential for possible use in production vehicles.
In addition to the tridion passenger cell, further components such as the doors are made of carbon-fiber-reinforced epoxy resin. The use of such materials enables a weight saving of more than 50% to be achieved compared with steel, or 30% compared with aluminum. Due to short hardening times, the resin systems from BASF are also suitable for producing larger volumes.
Heating. The multifunctional, lightweight seats in the smart forvision offer a combination of efficient temperature management and an energy-saving lightweight design. Here, several innovative products are combined with one another for the first time. A new, lightweight, self-supporting plastic seat shell forms the basis.
Numerous studies have shown that the body only absorbs heat efficiently through certain contact points. This is why “e-textiles”—thin fabrics with custom-tailored conductive coatings—replace conventional seat heating in the smart forvision. With direct heating close to the body in the middle and lower back area of the seats they provide for a pleasant feeling of warmth. The energy, space and weight-saving e-textile technology is also found in the armrests of the doors and ensures that body contact points sensitive to the cold are also warmed in this area.
The innovations continue with the seat foam, which provides for both comfort and weight savings. The material from BASF is around 10 to 20% lighter than other materials and enables different degrees of hardness to be realized in different areas of the upholstery in a single work operation – resulting in clear ergonomic advantages.
Superabsorbent containing fleece fabric integrated in the seat greatly enhances seating comfort through its passive climate control. Compared with conventional climate-controlled seats, the lightweight seat in the smart forvision does not have the complexity and energy requirement of mechanical ventilation.
Temperature management. As a large amount of energy is needed to air condition and heat a vehicle, temperature management was a key focus area for the smart and BASF researchers. A whole package of measures has been implemented in the smart forvision to ensure more efficient air conditioning of the vehicle. At the same time they make energy-intensive heating of the whole interior superfluous.
A heat shield that has not been previously used for automotive applications consists of a new kind of infrared-reflective film from BASF applied in the windscreen and side windows, protecting the car interior from heating up. Integrated between the panes of the safety glass the metal-free film ensures that the infrared rays are effectively reflected. Due to its high transparency in the visible range it can also be applied to tinted windows and guarantees an high level of reflection of sunlight and heat. Unlike metallized films, which are already used in some vehicles, the new film reflects only the infrared rays of the sun. Radio waves needed to use GPS, Bluetooth, mobile phones or for toll collection pass through the glass unhindered.
The high-performance foams from BASF fitted in the bodypanels also provide for a pleasant climate inside the car. They keep the vehicle cool in summer and also insulate it against the cold in winter. With high efficiency even in a small width, they can be fitted everywhere in the vehicle.
Cool coatings. The infrared-reflective and extremely scratch-resistant coating system covers two important aspects at once. First, it supports the extensive temperature management system and, second, the brilliant and high-quality look of the coating underlines the unique design of the smart forvision. The concept vehicle features a white special-effect coating with glass flakes that create a gleaming metallic look. An important side effect: the color white reflects heat rays from sun and light particularly well. But even surfaces coated with dark colors stay much cooler thanks to special color pigments from BASF. They ensure that heat radiation is reflected rather than absorbed. This leads to a temperature reduction of up to 20 °C on the paint surface and of up to approximately four degrees in the vehicle interior.