The Bavarian car manufacturer characterises a vehicle with a technology that uses digitalisation to adapt the exterior to different situations and individual wishes as an “advanced research and design project”. The body surface of the BMW iX Flow featuring E Ink can vary its colour tone at the driver’s request.
The flowing colour change is made possible by body foiling that is precisely adapted to the contours of the vehicle. At the CES, BMW demonstrated the technology using an electrically driven Sports Activity Vehicle.
Stimulated by electrical signals, the electrophoretic technology applies different colour pigments to the surface of each vehicle, causing the body image to take on the desired colouration. In doing so, the car manufacturer uses E Ink technology, which is otherwise used for far more inconspicuous purposes, such as dynamic price tags in supermarkets or as display technology for e-books. From the car manufacturer’s point of view, E Ink creates completely new possibilities to change the appearance of the vehicle to suit the driver’s aesthetic preferences, environmental conditions or even functional requirements. The technology thus offers unprecedented potential for individualisation in the field of exterior design, enthuses Adrian von Hooydonk, Head of BMW Group Design. The idea is to use this technology in the future to offer a new form of individualisation for both the exterior and interior of future production vehicles.
With this play of colours, BMW not only wants to allow its customers to express their changing moods and thus live out their ego. The technology is also intended to serve a functional purpose and contribute to greater energy efficiency: a white surface reflects significantly more sunlight than a black one. Consequently, in strong sunlight and high outside temperatures, the heating of the vehicle and its interior can be reduced by switching to a light exterior colour scheme, according to the car manufacturer’s reasoning.
In cool weather, on the other hand, the vehicle with a dark exterior absorbs noticeably more heat from the sunlight. In both cases, a targeted colour change can ensure that the cooling or heating output of the vehicle’s air conditioning system can be reduced. This reduces the energy demand of the vehicle’s electrical system and, with it, the fuel and power consumption of the vehicle. In a purely electrically driven car, the weather-dependent colour change can thus also contribute to increasing the range. In the interior, for example, the use of this technology could prevent the dashboard from heating up excessively.
The display in E Ink technology is applied to the car body as a precisely cut film.
E Ink technology is characterised by high energy efficiency. Unlike displays or projectors, electrophoretic technology does not require any energy to keep the selected colour state constant. Electricity only flows during the short phase of the colour change.
Electrophoretic colouring is based on a technology developed by E Ink. The surface coating of the BMW iX Flow featuring E Ink contains several million microcapsules, each with a diameter equal to the thickness of a human hair. Each of these microcapsules contains negatively charged white and positively charged black pigments. Depending on the setting selected, excitation by an electric field causes either the white or the black pigments to collect on the surface of the microcapsules, giving the body the desired colour.
Using laser cutting technology, the corresponding segments are then cut out of the E Ink film webs. This makes the two-dimensional material flexible enough to be applied to the three-dimensional car body. After the film segments have been applied and the power supply for the excitation of the electric field has been connected, the entire car body is heated and sealed to ensure optimal and uniform colour reproduction on the entire car body during each switching process.