Wacker silicones tailor-made, targeted for EV applications

MUNICH—To varying degrees across the world, environmental goals and regulations, consumer behavior and technological innovations are making e-mobility possible.

And that means continuous innovation on the materials side for Wacker Chemie A.G., which is keeping pace with its uniquely engineered silicones for thermal management, optical bonding and electrical insulation.

"Silicones support central functions in hybrid and electric vehicles," said Florian Degenhart, corporate communications and media relations director at Wacker, during a March 21 webinar. "This is one of the most exciting avenues for Wacker moving forward. We are convinced silicones are and will be key to e-mobility."

Indeed, silicone products are crucial to the efficiency of many components in an electric vehicle (using up to four times more silicone than an internal combustion engine vehicle) and are considered irreplaceable for their diverse performance properties.

Often lost in the discussion of the virtues of silicone is that it performs essential tasks unobtrusively. Without any invasion of neighboring departments, the material seals, dampens, conducts, insulates and protects against extreme heat and cold.

And this occurs in the engine compartment, drive area, the vehicle's interior, around the body and in the "power electronics."

"E-mobility is really a mega-trend in society," said Julia Henn, director of Wacker Industrial Solutions, which sits within Wacker Silicones. "E-mobility also is a game-changer to the automotive industry and to us as automotive suppliers."

Since Wacker manufactures nearly all its raw materials in-house, the company has the unique ability to tailor materials to customer needs—and there are many opportunities within an EV or hybrid.

Henn expects that by 2050, about 82 percent of global car sales will be of an electric variety.

"We expect the EV share to increase significantly from 2030 on," she said, adding that Wacker has 2030 pegged at about 26 percent of car sales to be EVs or hybrids. "Governments and the automotive industry have a clear strategy towards e-mobility."

In addition, consumer behavior is changing, she said, as more people accept alternative and sustainable mobility modes.

"And industry players are developing new concepts of electric, connected, autonomous and shared mobility," Henn said during the March 21 online presentation.

The regulatory environment by continent is worth noting as well, Henn said.

China remains the largest market for EVs with about 3.6 million EVs sold in 2022.

"China is the largest market with the largest growth rate, and this is in spite of strict regulation and subsidies that are partly expiring now," Henn said.

The Wuling Hongguang mini-EV is the top seller in China, at an equivalent of about $4,300 per vehicle, she said.

Europe was the second-largest market in 2022 with 2.4 million EVs sold, led by the Tesla Model Y.

"Here, Volvo is looking to go 100-percent electric by 2030," Henn said.

The U.S. continues to lag behind Europe and China in EV adoption (about 1.5 million EVs sold in 2022), due in part to relatively cheap fossil fuels and continued range anxiety from customers.

"In the U.S., electric mobility still is not a solid trend yet," Henn said. "But we believe that electro-mobility will accelerate in the future in the U.S., spurred in part by the Inflation Reduction Act."

About 200,000 EVs were sold in Asia, in regions outside of Greater China.

"There are some regional initiatives in India, but they really are the smallest market right now," Henn said.

Henn said the silicon-oxygen bond is the most important part to silicone chemistry—that and the highly flexible polymer chains.

These two unique attributes give silicone its chemically inert, water-resistant, oxydation-resistant and temperature-resistant properties, Henn said.

Translate that to an electric vehicle, and it means silicone can offer thermal management and event isolation.

And this second application benefit—event isolation—is perhaps more important than any other silicone use in the vehicle, Henn said.

In the event of a fire, or "thermal runaway" as the lithium battery fires have become known, portions of the battery housing ceramify and essentially insulate the battery from the fire around it.

"A lot of development is going on with car makers and battery safety at the moment," Henn said. "The biggest thing is ensuring more than 5 minutes of passenger safety in the case of thermal runaway.

"And Wacker does these things in-house, so we can really take up customer needs on a per-customer basis. The battery is the biggest thing in the car, so heat and thermal management is a very big topic."

In the electric engines that also are a part of EVs, silicones are used for cooling. And they help encapsulate the power electronics that wind in compartmentalized labyrinths throughout an EV.

In each car there are more than 100 sensors with electrical control units, all of which require encapsulation as well, Henn said.

Other EV areas that see heavy silicone applications include the cockpit display (optical bonding), fuel cells (sealing the bipolar plates), high-voltage cables (electrical insulation) and high-voltage connectors (also insulatory).

"I want to highlight the silicone gap fillers in particular," Henn said, "since they couple the battery modules to the cooling plate to dissipate heat."

Wacker's gap-filling abilities with silicone has allowed it to become a direct supplier to Tier 1 auto manufacturers—precisely because it develops such materials in-house and can cater material to how the OM wants to process the gap fillers.

"E-mobility is growing in all regions," Henn said. "And we have adapted our research and development centers accordingly."

She cited the global competence center for interface materials in Shanghai, and the innovation center in Seoul, South Korea, which focuses on the optical bonding for cockpit heads-up displays.

"Silicones play an important part in e-mobility, and these sales will increase from 2030 onward," Henn said. "Silicones do it safer, more reliably and more efficiently ... and we are well-positioned to supply the automotive industry moving forward."