On December 15th, Weilai Automobile ushered in its important event this year at Shanghai Oriental Sports Center. The second mass-produced model ES6 released at the meeting attracted widespread attention. It is worth mentioning that ES6 adds a carbon fiber board of about 2 square meters to the aluminum body, making it the only model in its class that uses an aluminum alloy + carbon fiber reinforced composite body structure.

Most of the key loads at the rear of the vehicle are borne by the carbon fiber rear floor. The three major components of the carbon fiber rear floor assembly, carbon fiber seat panel assembly, and carbon fiber rear floor cross member assembly of the NIO ES6 are provided by Kangdexin European Automotive Lightweight Design Center and Jointly designed by Weilai,

An analyst from Orient Securities said that a 10% reduction in car weight can increase its fuel efficiency by 6%-8%, and a 100 kg reduction in car weight can reduce fuel consumption per 100 kilometers by 0.3 liters to 0.6 liters. As one of the main ways to save energy and reduce emissions, lightweight is included in the energy-saving vehicle standard system.

Carbon fiber reinforced composite materials, known as "black gold", are becoming the new favorite of lightweight materials due to their light weight, high design freedom, and strong integration.

Reduce weight by more than 30%"

According to reports, the use of the carbon fiber rear floor in the ES6 model makes the overall torsional stiffness of the car body higher, the passive safety performance is improved, and the overall durability is also greatly improved. In addition, the carbon fiber rear floor is embedded in the all-aluminum body, which is more than 30% heavier than aluminum alloy. Compared with the same volume of high-strength steel, its weight is only 1/5.

Public information shows that carbon fiber is a new type of fiber material with high strength and high modulus fiber with a carbon content of more than 95%. Its strength is more than 2 times higher than that of ultra-high-strength steel, 30% lighter than aluminum, 50% lighter than steel, and 7-9 times stronger than steel. It is known as the "king of lightweight materials".

"Weight reduction is an important development direction for the future of automobiles." Zhang Dingjin, the former chairman and expert of China Composite Materials Group Co., Ltd., said in an interview with the Economic Observer that carbon fiber has obvious advantages in modulus and density, and it can be reduced by replacing steel. It weighs more than 40%.

While reducing weight, the car needs to consider the stress and impact resistance of the components to ensure safety.

"During a collision, carbon fiber composites can absorb energy 4-5 times that of steel, which can reduce the weight and improve the crash safety performance of the car." Shen, honorary director of the China Composite Materials Society, who has been engaged in carbon fiber research for a long time Really said when answering a question from a reporter from the Economic Observer.

Application speed

The application of carbon fiber-reinforced composite materials in the automotive field started with racing cars, and in recent years has also rapidly been widely used in civilian cars. As an important class of lightweight materials for automobiles, its application range is expanding from interior trim to exterior parts, body and structure.

Germany's BMW is a pioneer in the application of carbon fiber reinforced composite materials in the field of large-scale automobile production. In 2011, BMW released the i3 electric concept car and i8 hybrid concept sports car for the first time at the Frankfurt Motor Show. In 2014, i3 was successfully commercialized, and the commercialization and popularization of carbon fiber products in the field of General Motors took a step forward.

Zhang Dingjin said that at present, the world's major carbon fiber manufacturers and major automobile manufacturers have formed alliances to seek common development. "For example, Audi is owned by Voith, Mercedes-Benz, Toyota and Toray, General Motors and Teijin Toho."

Many industry insiders interviewed by the Economic Observer reporter said that compared with foreign giants, the application of domestic car companies in the field of carbon fiber is still in the initial stage of development and small-scale applications.

"At present, many domestic auto companies and carbon fiber composite materials companies are accelerating their deployment in the field of automotive carbon fiber materials." Shen Zhen said.

On June 30, 2018, the Qiantu K50, the first model of Qiantu Motors, was officially mass-produced off the assembly line at the Suzhou production base of Qiantu Motors. It is worth noting that the car body is made of carbon fiber materials and 29 carbon fiber composite materials are used in the whole car, which reduces the total weight by more than 40% compared with the weight of traditional steel plates.

Information from Kangde Composite Materials shows that the carbon fiber lightweight industry platform jointly created by Kangde Group and Kangdexin Group has started exchanges and cooperation with nearly 60 OEMs. Car carbon fiber composite material lightweight projects have been completed for body panels and body structure parts of a number of vehicle models. Cooperative car companies include: BAIC Group, Weilai, SAIC, Changan Automobile, Geely Automobile, Great Wall Motor, Weimar Automobile, etc.

Problems to be solved

Shen Zhen said that automotive carbon fiber lightweighting is the general trend of automotive lightweight development in the future, but the current lack of low-cost automotive carbon fiber and its intermediate material industry chain, and the problem of carbon fiber automotive maintenance are problems to be solved. "The problem of high cost is the biggest obstacle."

"The cost of enterprise evaluation is a comprehensive evaluation. Although the cost of carbon fiber materials is higher than that of steel, aluminum alloy and other materials, energy consumption and maintenance costs are reduced, so the life-cycle cost is reduced." According to He Peng, from the perspective of material costs alone , ES6's material cost is controlled within 300 yuan/kg, while the cost of using aluminum alloy materials is about 60 yuan-100 yuan under the same circumstances.

"Although almost all automobile companies in my country have formulated carbon fiber reinforced composite material development plans and established alliances with carbon fiber companies, there are still some development bottlenecks, such as the lack of composite material vehicle and parts design guidelines, evaluation standards and databases. , Lack of automated mass production technology and equipment for composite parts, etc." Yu Muhuo, professor of Donghua University and chief scientist of the National 973 Project, said in an interview with a reporter from the Economic Observer.

During the interview, the Economic Observer Network reporter learned that more than one industry expert held the same view.

Zhao Wei, a teacher at the School of Materials Science and Technology of Liaocheng University, who has been researching carbon fiber composite materials for a long time, said: "There is no unified system in the industrial field, and there is no mature manufacturing process and equipment, which directly leads to the inability to reduce costs. Theoretically, mass production is actually just one concept."

In Zhang Dingjin's view, the first challenge for domestic automobiles to adopt carbon fiber composite materials is the conceptual problem. "Composite materials should not be used as simple alternatives to metal materials. The focus is to establish a system solution for the application of carbon fiber composite materials in automobiles, and form an application concept that reduces the life-cycle cost."

"Secondly, carbon fiber manufacturers, carbon fiber composite material suppliers, and automobile manufacturers should establish a three-in-one strategic partnership to jointly develop carbon fiber automotive parts, establish and improve the design data and test methods of carbon fiber reinforced composite automotive parts, and the development is low. Cost carbon fiber materials, etc."