Magical colour change on the exterior: the BMW iX Flow featuring E Ink

MOBILITY/DESIGN: World premiere: Body surface with real colour change thanks to electrophoretic technology +++ Potential for future interior and exterior applications

Munich. In the interiors of current BMW models, digitalisation ensures a holistic user experience characterised by individuality and emotionalisation. My Modes offer drivers the opportunity to tailor the atmosphere in the interior to their personal mood and desired driving experience. With the BMW iX Flow featuring E Ink, the Munich-based premium carmaker is offering a glimpse of a future technology at CES 2022 that uses digitalisation to adapt the exterior of a vehicle to different situations and individual wishes. The body surface of the BMW iX Flow featuring E Ink can vary its colour at the driver’s request.

Frank Weber, Member of the Board of Management of BMW AG for Development: „In the future, digital experiences will not only take place on displays. The real and the virtual will increasingly merge. With the BMW iX Flow, we bring the car body to life.“

BMW iX Flow Featuring E Ink (prototype not for sale)

The flowing colour change is made possible by a specially developed body foiling that is precisely oriented to the contours of BMW’s all-electric Sports Activity Vehicle. Stimulated by electrical impulses, the electrophoretic technology brings different colour pigments to the surface in each case, through which the body image takes on the desired colouration. „The BMW iX Flow is an advanced research and design project and a good example of the forward thinking that the BMW Group continues to demonstrate. ,“ says Adrian van Hooydonk, Head of BMW Group Design.

The innovative E Ink technology 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. The BMW iX Flow featuring E Ink demonstrates this potential in an impressive way. On this basis, the BMW Group is pushing ahead with the development of the technology in order to bring a new form of individualisation to life in both the exterior and interior of future production vehicles.

Even today, the chosen body colour is an expression of the driver’s personality. The selection of exterior paint finishes available for current BMW models covers a broad colour spectrum. The tendency towards a particularly expressive, extravagant or sporty appearance on the exterior can be taken into account in this way, as can the desire for a discreet, subtle or elegant appearance. Year after year, new variants are added that are oriented to the characteristics of the respective model and with which the brand continues to set trends in the field of exterior design.

A whole new freedom of choice may emerge in the future through the use of innovative technology. „In this way, we give the driver the freedom to express different facets of his personality or even the joy of diversity to the outside world and to 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.“

Changing exterior colour as a contribution to increased efficiency.
A changeable exterior colour can also contribute to the well-being of the interior and the efficiency of the vehicle. This is done by taking into account the different abilities of light and dark colours in reflecting 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 exterior colour scheme. In cool weather, on the other hand, the vehicle with a dark exterior skin 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 E Ink technology itself 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.

Millions of microcapsules in a customised foil.
The electrophoretic colouring 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 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.

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. In the process, generative design and special algorithms are used to create a customised structure for each segment that is precisely matched to the lines and surface contours of the body.

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.

Photoset 1 to the article:


BMW iX Flow Featuring E Ink (prototype not for sale)


virtualdesignmagazine Michael Hiller



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