Electrical and Automotive Systems
Solid – Silicones
In the electronics lab in Burghausen, Germany, tension is mounting. The metering device starts moving almost as soon as the lab assistant has secured the engine controller circuit board on the test rig. The nozzle zig-zags across the circuit board, dispensing a viscous fluid onto the electronic components. The process is not complete until all the wires and chips have been coated with a thick layer of silicone. “It’s looking good,” says Julia Henn, head of the Industrial Solutions business team, who is watching the test closely. “It is crucial to completely cover the circuit board with silicone gel. Only then is it reliably protected.”
Car drivers never see the specialty gel that WACKER has developed in Burghausen and in Pangyo, South Korea. All the same, large quantities of this high-tech silicone can be found in virtually every vehicle. Each of the 60 control devices installed in the average mid-range car is coated with a protective layer of silicone. The sensors that supply data for ever more sophisticated driver-assistance systems are coated in silicone as well.
“When it comes to silicones, developers always contact us first.”
Dr. Wolfgang Schattenmann
Head of Rubber Solutions
“Whereas car production has increased by about 3 percent over the last five years, the demand for silicone gel has risen by a multiple of that,” says Henn. In addition, many of the displays in today’s vehicles are now bonded with a high-tech specialty silicone from WACKER. It is heat-resistant and does not yellow.
For over 60 years, WACKER has been developing silicones for the auto industry. It all started with lubricants, impact absorbers and cylinder-head gaskets. Then came spark plug boots, turbocharger hoses and radiator gaskets. “Now, our range includes 800 silicone products for the automotive industry – almost a third of our silicone portfolio,” says Dr. Wolfgang Schattenmann, head of the Rubber Solutions business team.
WACKER now supplies every major automotive contractor in the world. “When it comes to silicones, developers always contact us first,” explains Schattenmann, who has a doctorate in chemistry. Take mass dampers, for example. They suppress vibrations and ensure that driving is safe and comfortable. WACKER has developed a particularly robust silicone rubber for this application. “Silicones have the advantage of providing consistently good damping, regardless of how hot or cold the conditions are.”
Interior: switches, ambient lighting, cup holders
Rain sensor / camera: protective pane
PDC, radar, airbag sensors: gaskets
Dust protection, sleeves
Exhaust-pipe mounts: shock absorbers
Hybrid cables, weatherpacks
AdBlue systems: heating mats, seals
ABS / ESP systems: sealing, vibration decoupling
Cable protection: weatherpacks, sealing mats
Engine-oil system: non-return valves
Engine- / chargeair cooler: gaskets
Turbo-charger and radiator hoses
Lights: gaskets, optical lenses
Drive train: decoupling
Vibration dampers and shock absorbers
Electric auxiliary heater: seals
Spark plug boots, ignition and battery cables
Air circulation: valves, gaskets
Fuel cell: gasket
But the future belongs to electromobility. Sales of electric cars are still very modest. There are 45 million cars on German roads, but only 156,000 are electric or hybrid models. Nevertheless, the number of electric cars worldwide rose by 73 percent in 2016. In China alone, the number has tripled since 2015. Henn and Schattenmann agree: “The automotive industry is facing completely new challenges. Silicones are going to play an even greater role in the development of technical solutions.”
Batteries are just one example. Alongside electric motors and controllers, batteries are the most important component in the next generation of electric cars. Thermal management is one of the major challenges. Overheating considerably shortens the battery’s service life. One solution would be thermally conductive silicones, for which a dedicated production plant is being built in South Korea. They not only seal the battery, but also ensure highly efficient thermal management. Self-adhesive, electrically insulating silicones are already used in the on-board electrical systems of hybrid vehicles, ranging from high-voltage cables to weatherpacks.
What with electromobility, digitalization and autonomous driving, cars are being completely reinvented. Yet many materials are already reaching their limits. That is why industry is increasingly focusing on silicone. “Silicones still offer a huge potential and scope for development,” says Schattenmann, adding that this is true of both conventional combustion engines and battery-operated drives or fuel cells. “In a great many cases, silicones are simply the best alternative.”