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Electrification requires new materials for new challenges

As the engines of cars become more and more fuel efficient, ever more compact and increasingly more sophisticated in order to satisfy lower and lower emissions requirements, manufacturers face many industrial challenges. They have to explore how to build engines in ways that combine lightweighting, downsizing and the capacity to function in more aggressive environments (specifically with higher temperatures). On top of that, the rapid commercial take-off of hybrid and electric vehicles comes with its own challenges, as their engines are more complex.

The cooling system conundrum

One result of all this is that cooling systems in cars are challenged too, as there are more elements to cool down, higher temperatures to deal with and less space to fit it all. “Thermal management systems have become more and more complex,” confirms Brian Baleno, Head of Marketing for Transportation, at Solvay’s Specialty Polymers business unit. “Yet when manufacturers design an engine, cooling systems are one of the last things they look at. So they need a solution enabling them to design with very complex geometries, simply because there isn’t much space left.”

All this means the automotive industry is faced with the following conundrum: they can’t use metal because of its weight, they can’t use standard plastics because they couldn’t withstand the increasingly harsh conditions, yet they need a material that can be designed into intricate shapes. At least one thing is certain: traditional thermal management systems made of aluminum tubes bent into shape need to evolve - and that creates new opportunities in the high temperature thermoplastics market.

Ryton graphic

Thermoplastics with all the right features

Among Solvay’s wide portfolio of solutions that can help the transportation industry meet its lightweighting challenges, there is at least one thermoplastic that answers all of the above-mentioned requirements. Ryton® polyphenylene sulfide (PPS) is a high performance  thermoplastic that combines mechanical, chemical and thermal resistance with design flexibility. It’s also flame retardant, a desirable feature in high-temperature, high-voltage environments.

With features such as these, Ryton® PPS has unsurprisingly been used as a replacement for metal in cars and in the electronics industry for several decades now, primarily for the 30% to 50% weight reduction it enables. What’s new is the increasing extent of its applications, driven by manufacturers’ need for innovative material solutions. “Our R&I teams adapted Ryton® PPS to make it compatible with extrusion manufacturing instead of traditional injection molding,” explains Brian. “Thanks to this, more and more OEMs are adopting it to make highly specific cooling line parts, for which injection molding isn’t an option, which created a new application for an existing product.”

Moreover, the combination of properties offered by Ryton® PPS means it cannot only advantageously replace metal, but also ‘lower-performance’ plastics. On top of its resistance to heat, chemicals and mechanical stress, it also provides dimensional stability, meaning that parts maintain their original dimensions even when exposed to moisture or heat, which eliminates the risk of leakage, as gaps are less likely to appear between parts.

That’s even more true when the parts are all made with the same material. Legacy cooling systems usually combine metal and rubber that need to be hermetically crimped together: replace them with parts made of the same thermoplastic and you get perfect impermeability by eliminating the connection and thus reducing the risk of warranty issues. With the complex thermal management systems of hybrid and electric vehicles, that’s a precious safety feature to have.

We adapted Ryton® PPS to make it compatible with extrusion manufacturing, so more and more OEMs are adopting it to make highly specific cooling line parts, which created a new application for an existing product.

Brian Baleno, Head of Marketing, Transportation, Specialty Polymers, Solvay.

New opportunities through electrification

Beyond cooling systems, Ryton® PPS is also increasingly adopted for powertrain components as well as for parts in electric mobility systems, including belt starter generators, traction motors, power electronics, and fuel cells. Within these, applications such as sensors, connectors, bus bars, and rectifiers use Ryton® PPS.

Here too, it replaces other thermoplastics that just don’t offer the same characteristics. “The electrical properties of Ryton® PPS are yet another argument for its adoption,” continues Brian. “E-mobility is definitely a new area of growth, as it creates more opportunities to replace metal, for example in electronically-driven pumps. There are more water, oil and vacuum pumps in a hybrid car because there are more elements to cool, and you need to make them with weight optimization in mind on top of everything else, so you need a material that will enable you to do that.”

There currently is no other product on the market that combines all the properties this particular thermoplastic offers. Given the ever-longer list of constraints and requirements the automotive industry has to deal with in this day and age, as Brian puts it, “Ryton® PPS is a pretty obvious choice.”