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Plastics to Replace Aluminum

In the current generation of electric cars, the housings for batteries, motors and power electronics are made of aluminum – almost without exception. First of all, it is a good conductor of electricity. Second, it is a lightweight metal with a low specific weight. In addition, 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 pound of excess fat has an impact on the vehicle’s range. If you could replace the aluminum 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 manufacture of electronics, including displays.

One Goal, Multiple Paths

“These intrinsically more conductive plastics – that is, plastics that are conductive by their very nature – have proven to be too costly,” said Volker Schroiff, who is in charge of Technology Management at Freudenberg Sealing Technologies. “But for large-scale production, we’ve developed various alternatives that are less expensive.” The first 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 second 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 third approach that is well-suited to large surfaces – such as the housing cover for a traction battery. After a nonwoven’s fibers have been given an electrically conductive coating, the material is inserted into a mold where a plastic part is produced. “We’re working closely with the nonwovens experts at Freudenberg Performance Materials on this solution,” Schroiff said.