Some of the most brilliant developments of our time come from curious minds and for Australian engineer Dr Stella Clarke, a fascination for how things work ultimately led her to developing the world’s first colour changing car, the BMW iX Flow.
Growing up in a family where her mother and father held traditional values for what young girls should do, a career in tech was not something that Stella was proactively encouraged to pursue. But the indications were there from an early age that it was to be in her future as one of her favourite books was called ‘How things work?’ Stella now enjoys reading similar books to her own daughter as well.
At the completion of her Mechanical Engineering degree from the University of NSW, many of her cohort went into mining or roles like waste water treatment, but these didn’t very much excite Stella. From Australia via the USA, Stella ended up in Germany, a perfect place for an engineer with an inquisitive nature. She completed her PhD there, researching the teleoperation of robots with haptic input devices over networks, that allowed the operator to feel what the robot was doing.
This ultimately led to Stella starting work as a development engineer at the BMW Group in 2007. There she was responsible for the interior user interfaces like the knobs and dials and worked on both series development and concept development of those elements, as part of her role.
Almost ten years ago, inspired by eReaders and how they work, Stella started prototyping with E Ink (electrophoretic ink) in her spare time. E Ink works by using millions of microcapsules filled charged pigment particles in a fluid and the charged particles react to electric fields to create text or images, consuming energy only when changing the display. For this reason, eReaders are incredibly energy efficient.
“The colour changing layer is made from some pretty amazing material, which does real colour change and only needs a little bit of energy to do this and no energy at all to hold a colour, so it is bistable, it stays the same without any energy use at all,” explained Dr Clarke in a recent interview with Driven Women Magazine.
With access to a maker space, sponsored by BMW, at the Technical University of Munich Stella went about developing simple prototypes herself using the equipment available. Initially though these examples were not very convincing and most people that she showed were sceptical and didn’t think that it was a great idea. Undeterred Stella continued to work on them and with time her samples improved and she got better at pitching the idea.
“The short version of the story is that at some point I created a video pitch of the E Ink using imagery and video editing of the car changing colours and sent it around in BMW. This is ultimately gave the project more traction and got me a little a bit of funding to make even bigger samples,” said Dr Clarke.
The samples made were placed on the side of a car and using simple shapes that changed from white to black Stella was able to help people imagine what it would look like if the whole car changed colour. This was the prototype that led to the first car in the world that could change colour at the push of a button, the BMW iX Flow, which debuted at CES 2022 in Las Vegas.
The BMW iX Flow was a revolution and it has won many innovation awards including TIME Best Inventions 2022 and the 2022 FLEXI Award. It also led to Dr Clarke taking her work on colour changing cars from being just a, “hobby job or side job, to be her actual job job,” as the Project Lead for the BMW iX Flow.
“I didn’t know what the world would think of my work as this car was disruptive, something that the world did not expect. I was very proud taking the idea I first saw in an eReader to a car that changes colour,” shared Dr Clarke. The struggles that Stella, together with the teams at BMW and E Ink, faced in order to make the colour-changing car a reality were all worth it though when the whole world became fascinated with the BMW iX Flow at its launch.
Even so, the workshops can be a tough environment to work in as a woman. Stella admits that she has learned to do a little bit of acting and play by their rules by being a bit more like the men there, more direct and a little harsher in her voice than she would normally be, in order to fit in the workshop environment. However, being an Australian woman helps Stella look at problems in a different way to her German male colleagues.
“Many of these engineers used to build things with their dads and they learnt so much about engineering at a young age and they have a beautiful understanding of engineering. Whereas I had a different upbringing and sometimes approach engineering problems from a different angle as a result of that, which can lead to different or perhaps more creative ideas. Respect can be earned when they can see what you can do and what you can produce and increases when they see what you can achieve by just being a good engineer,” said Dr Clarke.
It can be an advantage, coming to issues from another angle and when Stella thinks back at how she has gone about her work, she acknowledges that she has always done things a little bit differently. It’s not just being a woman that benefits problem solving though, different backgrounds, cultures and experiences can help foster new and different ideas as well.
The development from going from a black and white colour changing car, to a car that changes multiple colours has been a smaller step in Stella’s opinion. The BMW i5 Flow NOSTOKANA is the most technical example yet of this colour changing ability produced to date at BMW. Sections of film that can be electronically animated were applied to the i5.
South African artist Esther Mahlangu was the first woman to paint a BMW Art Car, creating the 12th instalment in the collection in 1991. She applied traditional, vibrant Ndebele geometric patterns to a BMW 525i, breaking new ground as both the first female and first African artist in the series. The i5 Flow is named after Mahlangu’s first son, and the colours and patterns of Mahlangu’s art can be generated in constantly changing compositions on the vehicle.
“Seeing Esther Mahlangu sitting in that BMW Art Car and looking at her own artwork with a grin on her face inspired me to create the BMW i5 Flow NOSTOKANA. I have taken her joy and passion as my inspiration for this project,” revealed Dr Clarke.
Beyond artistic expression a car that can change the colour in the real world can match your mood, or from a practical standpoint it could indicate the amount of charge it has or help you find your car in a carpark by flashing. From a sustainability standpoint it could revert to a light colour to reflect sunlight and thereby make it more efficient to keep cool.
My initial thought on seeing the BMW iX Flow at the launch was how would you repair it? Stella explained that the panels have a protective layer to prevent damage, but if the panels were severely damaged in an accident they would ultimately have to be replaced. The other big question for me was when are we likely to see a colour changing car on the road?
“Stay tuned, it’s won’t be too much longer before we will start to see this technology in a more mainstream setting,” concluded Dr Clarke.
At the world premiere of the new BMW iX3 Long Wheelbase during Auto China 2026 held last month was also the BMW iX3 Flow Edition concept car. Its E Ink technology, seamlessly integrated into the bonnet, allows the driver to choose among eight carefully selected animations at the touch of a button.
For the first time, the E Ink technology has been integrated into a large-scale bodywork element and the concept car demonstrates the technology’s readiness for series production. Ranging from subtle to expressive, the design makes innovation visible and conveys the driver’s style and mood in a personalised and context-sensitive way. By integrating this technology into the bonnet of the BMW iX3 Flow Edition, the BMW Group has taken E Ink to a new and exciting level and I can’t wait to see what more is to come from the E Ink technology!
Photographs by BMW Group.