This answer must be carbon fiber.

Carbon fiber (CF), which is a microcrystalline graphite material obtained by stacking organic fibers such as flake graphite crystallites along the axial direction of the fiber and carbonized and graphitized. The carbon content is above 95%. High strength material.

Carbon fiber is not only expensive, but also because of its complicated production process, which leads to insufficient production and cannot replace traditional steel and aluminum alloy. Carbon fiber costs at least $20 per kilogram, compared to less than $1 per kilogram for traditional steel materials.

In the new generation of 7-series body frames, carbon fiber is limited to the most important places: reinforced roof beam structure and B-pillar and C-pillar, bottom side wall, central channel and rear support. It can be made of high-strength steel. It can be directly reduced by more than 50% by the combination of steel and carbon fiber, and the strength is 7-9 times that of steel. Finally, the 7 series is lighter than the previous generation by 130kg.

In addition to weight reduction, carbon fiber also significantly optimizes the rigidity of the BMW 7 Series. The carbon fiber-reinforced B-pillar does not deform due to impact, and the high-strength steel and carbon fiber mix will disperse the impact and improve the safety of the vehicle. performance.

In all sports and luxury models, the role of the sub-frame is very important. This is placed on the bottom of the chassis and is mainly responsible for connecting the engine, suspension and body parts. The sub-frame is a key component in the construction of the vehicle, designed to increase the strength of the vehicle and prevent collision deformation.

There used to be a car factory looking to use aluminum alloy instead of steel to create a sub-frame, which can greatly reduce the weight, but later found that the strength of the aluminum alloy is still not enough, and finally can not use the bulky material of steel.

So someone finally remembered the carbon fiber

Cadillac CTS-V and its carbon fiber hood

The use of carbon fiber reinforced composites in chassis applications is very advantageous for reducing vehicle weight, but the technical challenges are also very large. For example, the two companies introduced computer-aided engineering (CAE) for R&D, but since CAE analysis cannot achieve evaluation of vehicle corrosion resistance, stone-resistance test, and bolt load retention capability, a large number of actual tests are still required.

The battery can not lose weight, carbon fiber is the best material for electric vehicles

Since the introduction of carbon fiber into the Formula 1 car by McLaren in 1981, it has remained the best manufacturing material for racing cars and supercars. In the case of the F1 car, in addition to the fact that a very small number of parts such as engines have to be made of conventional metals, they are widely used in places where carbon fiber can be used.

Monolithic shells, body shells, suspension components, and even gearbox housings that protect rider safety are the best in the world.

BMW i3 electric car full carbon fiber difficult frame

At present, the popularity of new energy electric vehicles, but technically still can not solve the weight of the battery pack, in order to reduce weight can only make an article on the body material, so lightweight and can support the heavy carbon fiber of the body and become the best material.

BMW has done this in the morning. In the i3 electric and i8 hybrid models, carbon fiber was the main material for the body structure for the first time. BMW even plans to apply carbon fiber to more models to reduce the weight of the car.

By Claudine