BMW Unveils First Color-Changing Car
German automobile and motorcycle manufacturer BMW recently revealed a first-of-its kind car that changes color using technology found in eReaders. The BMW iX Flow premiered at CES 2022 in Las Vegas at the beginning of the month.
“Digital experiences won't just be limited to displays in the future,” said Frank Weber, Member of the Board of Management of BMW AG, Development. “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.”
Drivers can change the vehicle’s color using a phone app, switching between shades or changing the design, such as racing stripes. BMW research engineer Stella Clarke said, in the future, changes could also be controlled by a button on the car’s dashboard or even by hand gestures.
While currently the vehicle can switch between black and white, BMW plans to expand the technology to cover many colors.
The electrophoretic coloring is based on a technology developed by E Ink that is also used in eReaders, described as a kind of “digital paper.” Millions of microcapsules are contained inside the coating laminate, each the diameter equivalent to the thickness of a human hair.
The microcapsules contain negatively charged white pigments and positively charged black pigments. An electric field then causes the white or black pigments to collect at the surface of the microcapsule when a setting is chosen, changing the color of the car to white or black. This creates an Electronic Paper Display, or EPD.
Many triangular, fitted ePaper segments are applied to the vehicle body and tire rims, with generative design processes implemented to ensure the segments reflect the contours of the vehicle and resulting variations in light and shadow. The algorithms also enable the formability and flexibility to tailor the ePaper to the design lines of the car.
Each segment is created using high precision laser cutting technology before being applied to the vehicle. Once connected the electrical field power supply, the body is warmed and sealed to guarantee uniform color reproduction.
The E Ink technology is reportedly energy efficient, requiring no energy to keep the chosen color state, unlike displays or projectors. Currently only flows when the colors are changing.
According to BMW, changing the vehicles appearance with E Ink offers options for driver’s aesthetic preferences, environmental conditions or functional requirements.
“This gives the driver the freedom to express different facets of their personality or even their enjoyment of change outwardly, and to redefine this each time they sit into their car,” said Stella Clarke, Head of Project for the BMW iX Flow featuring E Ink. “Similar to fashion or the status ads on social media channels, the vehicle then becomes an expression of different moods and circumstances in daily life.”
Being able to switch from black to white also benefits the interior and efficiency of the vehicle. While lighter surfaces reflect more sunlight, darker surfaces can help absorb heat to keep the car warm. Drivers would be able to shift between white or black in different weather, cutting the amount of cooling and heating required from the air conditioning.
This reduces the amount of energy on the vehicle’s electrical system, lowers the amount of fuel or energy consumption and increase the range in electric vehicles, like preventing the dashboard from overheating.
In the future, BMW hopes to add additional features, such as a flashing exterior to help drivers locate their car. Currently, no production or cost for the BMW Ix Flow has been announced.
Other Color-Changing Coatings
While the technology BMW has utilized is new to the market, researchers have previously created coatings that change color using heat or nanotechnology.
In 2015, a research team in China developed a coating that relies on nano-size cells that can be controlled to inflate or deflate, and, as a result, deflect visible light in different wavelengths. According to an article in the South China Morning Post, the result is a wall that acts like a chameleon—and changes color to match the environmental change.
“Imagine a house that will cheer you up with a bright color when it rains,” Du Xuemin, the lead scientist of the project, told the daily newspaper.
“Imagine the fun of instantly changing the color of everything, from the wall to the floor to the furniture, just by swiping a smartphone,” said Du. “Our paint will make these dreams come true.
According to the research progress report on the Shenzhen Institutes of Advanced Technology website, Du and his colleagues developed "a color tunable electrochemical photonic device by using redox of metal ions as the trigger to tune the band-gap of photonic crystal beads." In other words, the cells change color to a chemical reaction, and then back to their original color, without losing any of the color quality, the team said.
The daily newspaper said that in the core of each nano-cell is a kind of metal, such as copper. When electricity is applied to the cell, it gives it a positive charge that pulls the cell’s crystalline shell inward.
Other ways to cause the reaction? Spray the cells with water, or change the temperature of the room, the newspaper said.
The paint does not generate its own light and unlike the screens on electronic devices—such as Amazon’s Kindle—it is cable of generating many colors, not just black and white.
In 2017, British artist Stuart Semple released new color-changing paint products, Phaze and Shift. Phaze leaves an ultra-matte coat that changes from purple to bright pink when exposed to heat over 80 degrees Fahrenheit. Shift can be applied over Semple’s Blackest Black to form a multi-colored, almost iridescent sheen.
The secret behind the paint’s ability to change color? Chiral nematic liquid crystal. Semple has described it as “living substance, more expensive than gold.” The liquid crystal is sold in a bottle of rainbow fluid, which needs to be stored in a refrigerator and shaken once in a while to keep it “alive.”