BMW reveals color-changing concept car at CES 2022

Last week at CES 2022 in Las Vegas, BMW revealed a new concept car that allows the driver to change the exterior car color of the BMW iX Flow.

"Digital experiences won't just be limited to displays in the future. There will be more and more melding of the real and virtual. With the BMW iX Flow, we are bringing the car body to life," said Frank Weber, member of the board of management of BMW AG, development.

The fluid color changes are made possible by a specially developed body wrap tailored to the all-electric sports activity vehicle from BMW. When stimulated by electrical signals, the electrophoretic technology brings different color pigments to the surface, causing the body skin to take on the desired coloration.

The E Ink technology opens new ways of changing the vehicle's appearance in line with the driver's aesthetic preferences, the environmental conditions or even functional requirements. 

A variable exterior color can also contribute to wellness in the interior and to the efficiency of the vehicle, BMW said. This is done by taking account of the different abilities of light and dark colors when it comes to reflecting sunlight and the associated absorption of thermal energy. A white surface reflects a lot more sunlight than a black one. BMW says that heating of the vehicle and passenger compartment as a result of strong sunlight and high outside temperatures can be reduced by changing the exterior to a light color. In cooler weather, a dark outer skin will help the vehicle to absorb noticeably more warmth from the sun.

In both cases, selective color changes can help to cut the amount of cooling and heating required from the vehicle's air conditioning. This reduces the amount of energy the vehicle electrical system needs and also the vehicle's fuel or electricity consumption. In an all-electric car, changing the color in line with the weather can also help to increase the range. In the interior, the technology could, for example, prevent the dashboard from heating up too much, BMW says.

Electrophoretic coloring is based on a technology developed by E Ink that is most well-known from the displays used in eReaders. The surface coating of the BMW iX Flow featuring E Ink contains many millions of microcapsules, with a diameter equivalent to the thickness of a human hair. Each of these microcapsules contains negatively charged white pigments and positively charged black pigments.

Depending on the chosen setting, stimulation by means of an electrical field causes either the white or the black pigments to collect at the surface of the microcapsule, giving the car body the desired shade.

Achieving this effect on a vehicle body involves the application of many precisely fitted ePaper segments. Generative design processes are implemented to ensure the segments reflect the characteristic contours of the vehicle and the resulting variations in light and shadow. The generative design algorithms enable the necessary formability and flexibility required to tailor the ePaper exactly to the design lines of the vehicle.

Laser cutting technologies guarantee high precision in generating each segment. After the segments are applied and the power supply for stimulating the electrical field is connected, the entire body is warmed and sealed to guarantee optimum and uniform color reproduction during every color change.