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The Independent Automotive Aftermarket Federation

Uninterrupted lightness [Freudenberg Sealing Technologies]

Date: Monday 20 June 2022

We have developed various cost-effective alternatives for large-scale production
(Volker Schroiff, Director, Technology Management, at Freudenberg Sealing Technologies)

Plastics can do more than just insulate – they can conduct electricity as well. With the help of special plastics and coatings from Freudenberg Sealing Technologies, a vehicle can shed a few pounds.
Plastic to replace aluminium.

In the current generation of electric cars, the housings for batteries, motors and power electronics are made of aluminium – almost without exception. First of all, It’s a good conductor of electricity. Second, it’s a lightweight metal with a low specific weight. It is easily processed with pressure-casting, making it a low-cost option. To the experts at Freudenberg Sealing Technologies, all this is good – but not good enough – since every £ of excess fat has an impact on the vehicle’s range.

If you could replace the aluminium components with plastics, you could reduce the vehicle’s weight even more. But there is an obstacle – You need an electrically conductive plastic for this. This form of plastic does exist, but it is quite expensive and is almost exclusively used in the manufacturer of electronics.

One goal, multiple paths
“Plastics that are conductive by their very nature – have proven to be too costly, said Volker Schroiff, Director of Technology Management at Freudenberg Sealing Technologies. But for large scale production, we’ve developed various alternatives that are less expensive.”

  • The 1st alternative is a plastic housing with a conductive coating, which is applied like paint. Along with colleagues at the Special Sealing business unit, Schroiff is working on a way to industrialize the process.
  • The 2nd alternative is to impart plastic particles of a conductive material to a nonwoven before the injection molding stage.

The advantage of this approach: no additional steps are needed in the production process. This offers cost advantages, especially for relatively small components. And in the end, there is a 3rd approach that is well suited to large surfaces, such as the housing cover for a traction battery. After a nonwoven’s fibres have been given an electrically conductive coating, the material is inserted into a mould where a plastic part is produced. We’re working closely with the nonwoven experts at Freudenberg Performance Materials on this solution, Schroiff said.

Starting with an annual production of at least 30,000 parts, these special plastics from Freudenberg Sealing Technologies are less costly than aluminium.

In an electric powertrain, the electricity seldom flows in one direction. The car’s power electronics send alternating current at high frequencies into the veins of the electric motor, which – depending on its design, runs at rotational speeds up to 30,000 rpm. Field strengths change at a corresponding rate, producing electromagnetic waves that move through the space at the speed of light. If they are not stopped, one major result will be the disruption of the many control units on board, and maybe even in a car stopped at the traffic light. The only reliable option in the battle against electromagnetic waves is to confine electric components to a housing made of an electrically or perhaps magnetically conductive material or whose electrically conductive surface reflects the waves.