BY ALT Technologies | 15th July 2020
Automotive interiors and electric vehicles are upgrading with the latest advancements in flexible printed electronics, including HMI (human-machine interface), seat and armrest heating, and lighting displays.
Printed electronics and conductive ink applications have been around for decades, with OLEDs (organic light-emitting diodes) and solar panels leading the way in functionality.
However, printed electronics have a new dynamic since the electric vehicle market thrives with the latest automotive advancements. This article will discuss these recent developments: heaters, lighting, sensors and HMI.
What do we mean when we say “printed electronics?” It involves printing technology that creates various applications such as RFIDs, sensors, electronic circuits, and displays. For example, you can print carbon-based, convectional inks on flexible substrates such as PET.
The driving force behind this type of printing is how lightweight the solutions are, making them a sustainable choice due to their thin layers and less material. The emergence of interactive displays and touchscreens, controls powered by voice commands, remote devices and IoT connectivity are also critical factors in the uptake.
Printed electronics allow automotive suppliers and developers to take their solutions to the next level. For example, in most cars, a lot of heat is wasted in space that the passenger does not occupy: a heat sink. Novel printed electronics capabilities are flexible and self-regulated, making them easier to install in small areas such as the car armrest and can connect throughout the vehicle.
A typical flexible heater comprises a heating element, either an etched foil or a wire wound heating element. These heating elements are packed between material layers that allow heat transfer from the materials to the application. In addition, some form of resistance is used within the elements to create heat.
Wire heaters use very thick wires (measured in millimetres), so they must be covered in a thicker material not to feel the wires. However, printed ink layers are much thinner (microns instead of millimetres) and can be placed much closer to the surface, making them a more efficient choice.
Conductive ink is an essential component of the functionality of printed electronics. Inks such as silver or copper are used to transport electricity. They are used to print flexible electronic circuits on various materials and make objects conductive, more communicative or capable of storing information, such as ADAS (advanced driver-assistance systems).
PTC heaters are well known for their safety, elasticity, flexibility, and ease of use. PTC heaters work well by producing safe and comfortable low heat. PTC carbons work as electrical resistance and heat up when a current is applied. A full range of positive temperature coefficient (PTC) conductive inks can be combined with flexible substrates such as polyester (PET) or polyimide (PI).
Their carbon ink has resistive properties that change with temperature. As the heater reaches an equilibrium, the resistive elements stabilise, and the flow decreases through the heater. This process repeats, with minor fluctuations.
PTC carbon-based heating is self-limiting and does not require a controller. The heater is designed to “shut off” at a pre-determined temperature. This is considered a “self-limiting” heater without external diagnostics or controls.
With the large EV batteries, OEMs must keep vehicle weight to a minimum. One way of achieving this is through creative cabling system solutions in the vehicle interiors. As mentioned above, printed heaters are temperature-automated and flexible, unlike traditional automotive heaters, making installing interior parts easy.
Printed electronics can be used in various lighting applications in electric vehicles (EVs) to create flexible, cost-effective and lightweight lighting solutions. Printed LED lighting strips can be used for ambient lighting in the interior of the EV. These adjustable LEDs can be integrated into seats, roof or door panels, or other interior surfaces to create a visually appealing and customisable lighting experience for passengers.
Human-machine interface (HMI) applications within electric vehicles (EVs) assist in intuitive and user-friendly interfaces. Printed electronics can be combined with haptic technology to provide tactile feedback when interacting with touchscreens or other control surfaces. This enhances the user experience by physically confirming button presses or screen interactions.
Printed capacitive touch controls can be incorporated into various parts of the vehicle’s interior, such as the steering wheel, door panels, or armrests, to enable touch-sensitive controls for audio volume, phone calls, or cruise control.
Although there are clear advantages, such as flexibility and being lightweight, there is much more to vehicle interior printed electronics than meets the eye.
Comfort heating can be integrated with any area of the car to support interior heating, providing a premium customer experience. It also ensures the passenger is heated efficiently, therefore not wasting any energy heating areas of the car where the passenger is not situated. This is a crucial component in conserving energy in electric vehicles.
Active safety features within cars attempt to prevent and mitigate collisions. LED tail-lighting systems and phygital shield capabilities now have a much more extensive segment range, meaning more light-emitting options. Flashing, colour options and communication design can enhance these vehicles to alert other drivers and pedestrians when a car is turning or when a vehicle gets too close behind.
HMI Printed electronics can seamlessly integrate into various parts of the vehicle’s interior, including curved surfaces and unconventional shapes. This enables automakers to make the most efficient use of available space and create a cohesive design.
Although printed electronics have existed for some time, these automotive applications are relatively new. Working with experienced automotive suppliers ensures your product solutions are tried and tested and adhere to strict requirements and specifications.
ALT Technologies not only works day in and day out with these stringent demands, but we also have a combined 50 years’ worth of printing knowledge. Our understanding of various substrates, inks and adhesive materials, printing processes, and die-cutting allows us to make light, heat and HMI product-driven decisions. In addition, our experience with curing, flexo screen printing, silver inks, resin and powders enables us to choose the correct printed electronics functionality.
Our teams constantly research materials that best upgrade and suit our customers’ applications. Please contact us today if you would like to learn more about these materials and processes or how we can work together on heating and lighting printed electronics.
