At CES 2022, BMW is offering a glimpse of a future technology that allows the exterior of a vehicle to be adapted to different situations and individual wishes. For a start, the body surface of the BMW iX Flow featuring E Ink can vary its color at the touch of a button.
The flowing color change is made possible by a bodywork foil coating precisely adapted to the contours of the electrically powered Sports Activity Vehicle. Stimulated by electrical impulses, the electrophoretic technology brings different color pigments to the surface in each case, through which the body image takes on the desired coloration.
The innovative E Ink technology creates completely new possibilities for changing the appearance of the vehicle to suit the driver's aesthetic preferences, environmental conditions or even functional requirements. The BMW iX Flow featuring E Ink impressively demonstrates the resulting potential for individualization. The BMW Group is continuing to drive forward the development of E Ink technology - with the intention of enabling a new form of individualization to be experienced in both the exterior and interior of future production vehicles.
»Digital experiences will not only take place on displays in the future. The real and the virtual will increasingly merge. With the BMW iX Flow, we are bringing the body to life,« explains Frank Weber, Member of the Board of Management of BMW for Development.
Even today, the body color chosen is an expression of the driver's personality. The penchant for a particularly expressive, extravagant or sporty appearance on the exterior can be taken into account, as can the desire for a discreet, subtle or elegant appearance. The new technology creates a whole new freedom of choice.
»In this way, we give drivers the freedom to express different facets of their personality or even the joy of diversity to the outside world and redefine them on every journey,« says Stella Clarke, head of the BMW iX Fow featuring E Ink project. »The vehicle then becomes an ambassador of different moods and situations in everyday life, similar to fashion or the status displays on social media channels.«
A changeable exterior color can also contribute to the well-being of the interior as well as to the efficiency of the vehicle. To this end, the different properties of light and dark colors are taken into account in the reflection of sunlight and the associated absorption of thermal energy.
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 color scheme for the exterior. In cool weather, on the other hand, the vehicle with a dark exterior absorbs noticeably more heat from sunlight.
In both cases, a targeted color change can ensure that the cooling or heating output of the vehicle's air conditioning system can be reduced. This reduces the energy requirements of the vehicle's electrical system and, with it, the vehicle's fuel and power requirements. In a purely electrically powered vehicle, the weather-dependent color change can thus also help to increase the range. In the interior, for example, the use of this technology could prevent the dashboard from heating up excessively.
E-ink technology itself is characterized by high energy efficiency. Unlike displays or projectors, electrophoretic technology does not require any energy to keep the selected color state constant. Electricity only flows during the short phase of the color change.
The electrophoretic coloring is based on a technology developed by E Ink and used in a similar form in e-book readers. The surface coating of the BMW iX Flow featuring E Ink contains several million microcapsules, each with a diameter equivalent 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 ensures that either the white or the black pigments collect on the surface of the microcapsules, thus giving the body the desired color.
The e-ink surfaces consist of precisely cut ePaper foils that are applied to the body of the vehicle. To ensure that the foiling also reproduces the characteristic contours of the vehicle and the resulting light and shadow gradients, a 3D model of the respective body segment is divided into individual segments of different sizes and transferred to a two-dimensional pattern. Generative design and special algorithms are used to create a customized structure for each segment that is precisely matched to the lines and surfaces of the body.
Laser cutting technology is then used to cut the corresponding segments 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 excitation of the electric field has been connected, the entire car body is heated and sealed to ensure uniform color reproduction across the entire car body during each switching process.