E Ink Joins Forces with Premium Automaker Showing the BMW iX Flow, a car that is wrapped in Digital Paper Technology at CES 2022. BMW is offering the prospect of a future technology that uses digitisation to also adapt the exterior of a vehicle to different situations and individual customisation. The surface of the BMW iX Flow featuring E Ink can change its shade as the driver wishes.
The fluid colour changes are made possible by a specially developed body wrap that is tailored precisely to the contours of the all-electric Sports Activity Vehicle from BMW. When stimulated by electrical signals, the electrophoretic technology brings different colour pigments to the surface, causing the body skin to take on the desired colouration.
The innovative E Ink technology opens completely new ways of changing the vehicle’s appearance in line with the driver’s aesthetic preferences, environmental conditions or even functional requirements. The technology thus offers potential for personalisation of the car’s exterior design. The BMW iX Flow featuring E Ink demonstrates this potential to impressive effect. Against this background, the BMW Group is driving the development of the technology so that a new form of personalisation can be experienced both on the outside and on the inside of future production vehicles.
How a variable exterior colour can increase efficiency
A variable exterior colour can also contribute to the efficiency of the vehicle by taking into account the different abilities of light and dark colours 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. By implication, 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 colour. In cooler weather, the dark outer colour will help the vehicle to absorb noticeably more warmth from the sun, thus also affecting the interior and not just the exterior of the vehicle for the owner.
In both cases, selective colour 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 with it also the vehicle’s fuel or electricity consumption. In an all-electric car, changing the colour in line with the weather can therefore also help to increase the range. In the interior, the technology could, for example, prevent the dashboard from heating up too much.
E Ink technology itself is extremely energy efficient. Unlike displays or projectors, electrophoretic technology needs absolutely no energy to keep the chosen colour state constant. Current only flows during the short colour changing phase.
Millions of paint capsules in a custom wrap
Electrophoretic colouring 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 an electric 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 colour reproduction during every colour change.
