Research on the high technology of carbon fiber in the automotive field

Experimental data show that if the total weight of a vehicle is reduced by 10%, fuel consumption will be reduced by 6%-8%, carbon emissions will be reduced by 4%-10%, and braking performance, acceleration performance, and handling performance will all be improved. Therefore, lightweighting is an important way to reduce emissions and increase efficiency. Among all types of lightweight materials, carbon fiber has the highest cost, but it has the highest tensile strength and specific strength, and the best weight reduction effect, making it an ideal lightweight material.

Replacing the current steel body with a carbon fiber composite structure can significantly reduce weight by up to 60%, thereby improving fuel efficiency by more than 30%. Following foreign OEMs such as BMW, Audi, and Mercedes-Benz, in 2024, China’s Yangwang and Xiaomi began to achieve lightweighting through carbon fiber bodies. Representative models include BYD Yangwang U9, Mengshi M-HUNTER Hunter, Xiaomi SU7 Ultra prototype, Great Wall Tank 700Hi4-T, etc.

For example, the Xiaomi SU7 Ultra prototype, which will challenge the Nordschleife of the Nürburgring in October 2024, uses 100% carbon fiber outer coverings and composite chassis parts. The car will replace all 24 parts, a total of 15㎡, with carbon fiber materials, and the lightweight weight reduction plan armed to the teeth will make its total weight loss greater than 500kg.

Hengrui (HRC), a supplier of carbon fiber composite products, once said, “In 2024, the number of carbon fiber body cars produced in China is expected to reach more than 10,000, and by 2025, this number is expected to break through.” This shows that all-carbon body has become the focus or goal of lightweighting for all OEMs. However, high costs will be a major obstacle. After all, the all-carbon body of the Xiaomi SU7 Ultra prototype costs tens of millions of CNY.

Super Electric Drive

In August 2024, GAC Aion Quark Electric Drive 2.0 rolled off the production line. Its biggest technological innovation is the use of amorphous-carbon fiber super electric drive, the core of which is the combination of amorphous alloy stator and carbon fiber high-speed rotor. It is an innovative attempt to cleverly integrate two seemingly unrelated advanced materials, amorphous alloy and carbon fiber, into one motor.

Compared with traditional motors, amorphous-carbon fiber super motors have shown incomparable advantages in many aspects. In terms of efficiency, its energy conversion efficiency can be as high as 98%, far exceeding the average level of traditional motors; in terms of power density, the motor can output more power per unit weight or volume. In the field of new energy vehicles, this motor will become the key to improving cruising range, acceleration performance and vehicle lightweighting.

According to the goal of the Energy-saving and New Energy Vehicle Technology Roadmap:

By 2025, the curb weight of new energy vehicles will be reduced by 20%, the amount of carbon fiber per vehicle will be ≥2%, and the price of carbon fiber will also drop to 80-120 yuan/kg. By 2030, the amount of carbon fiber per vehicle will be ≥5%, and the price of carbon fiber will also drop to 65 yuan/kg.

It can be foreseen that the amount of carbon fiber will increase from 2025 to 2030, and its application in parts such as body, drive shaft, seat, trunk lid, anti-collision beam, etc. will gradually increase.