Carbon Fiber Joins Fight for EV Battery Cases

Electric vehicles are shaping up to be a key battleground for materials. Lightweighting is just as important here—if not more so than in conventionally powered models—as carmakers look for ways to boost EV efficiency and minimize range anxiety.

This not only pits aluminum and high-strength steel against each other, it also opens the door for a more exotic (and lighter) competitor: carbon fiber.

Underfloor Benefits

Carbon fiber EV battery case. (Image: SGL Carbon)

Germany’s SGL Carbon says it has secured contracts to supply part or all of the battery housing in two dedicated EV platforms. One is said to be a high-volume application with a North American carmaker, while the other is for a European-badged sports car.

SGL also supplied the battery case for a prototype EV developed in China.

Such architectures package the battery within a “skateboard” chassis. In addition to cutting weight, the supplier claims, carbon fiber is the best choice to meet the design’s requirements for:

• Stiffness
• Impact resistance
• Thermal management
• Impermeability

What about costs?

SGL didn’t say anything about costs, which have long plagued the pricey material. For the most part, carbon fiber applications have been limited to motorsports, supercars and other niche models.

But that’s starting to change. In fact, carbon fiber recently scored a couple of high-profile wins: the curved bumper in the mid-engine C8 Corvette and a pickup bed option in the GMC Sierra Denali. The 2020 Mustang Shelby GT500 also offers an optional carbon fiber package (an adjustable track wing, splitter wickers and 20-inch wheels).

In 2018, SGL reportedly netted more than $1.1 billion in carbon fiber sales, primarily to BMW and Volkswagen Group. Interestingly, last summer the company downgraded its earnings forecast through 2022, although this was attributed to shortcomings for non-automotive customers.

The new EV orders, which are due to start later this year, bode well for the future. Pointing to OEM plans to introduce EVs across their lineups in coming years, SGL says it’s in talks with several other companies about new applications.

But the competition will be fierce. Aluminum suppliers such as Constellium and Novelis are making their own cases to win a piece of the EV business.