Carbon fiber is as thin as hair and light as a feather. The diameter of a single fiber is only 5 to 7 microns, which is about one tenth of the thickness of human hair, and the density is only about 1/4 of that of steel. At the same time, it is as strong as steel. A one-meter-long T1000 grade carbon fiber weighs only about 0.5 grams, but it can bear a pulling force of about 500 kilograms.

With superior mechanical properties, as well as corrosion resistance, oxidation resistance, no rust and other characteristics, carbon fiber is now added to resin, metal, ceramics, concrete and other materials, becoming an important reinforcement material for the manufacture of advanced composite materials, and its application range is increasingly wide. Become the "king of new materials" in many people ".

From baseball bats and tennis rackets, to bicycles, cars, wind blades, to large aircraft, launch vehicles ...... In the exhibition hall of the Zhongfu Condor Carbon Fiber Production Base in Xining, Qinghai, the exhibits of physical objects and models are dizzying, demonstrating that the application of this new material is expanding towards high-end industrial manufacturing and cutting-edge technology.

As an important market for carbon fiber, China's carbon fiber once relied heavily on imports, and the price was very expensive. Therefore, carbon fiber is also known as "black gold". At that time, the high-performance T700 grade carbon fiber on the market had sold at a high price of millions of yuan per ton. Later, when the domestic high-performance carbon fiber "blossomed", the price of carbon fiber in the international market fell back.

Domestic carbon fiber development of two major "potential stocks" in the field

01 wind turbine blade carbon fiber blade application has become a trend

In recent years, the installed capacity of domestic wind power has increased rapidly. According to the latest data from the National Energy Administration, in the first seven months of this year, the newly installed capacity of domestic wind power reached 26.31 million kilowatts, with a cumulative installed capacity of 0.39 billion kilowatts. With the advent of the era of parity, the trend of large-scale fans is particularly prominent, land fan capacity of up to 10 MW, offshore fan capacity of 18 MW, blade length is also constantly refreshing industry records.

Rapid large-scale to the fan blade material performance to bring a new test, the traditional glass fiber composite material performance is insufficient, carbon fiber has become the latest "potential stock".

Huang Xuan pointed out that compared with glass fiber, the specific modulus and specific strength of carbon fiber are greatly increased. Carbon fiber composite materials have lower density and higher strength than glass fiber composite materials, which breaks through the performance limit of glass fiber materials and can ensure that fan blades reduce weight while increasing length. "The use of carbon fiber blades can further enhance the design limit of offshore wind turbines, and even support the development of units with 20 MW and 300 m impeller diameter."

In addition to providing protection for the large-scale offshore wind turbines, the industry generally believes that with the continuous expansion of the scope of offshore wind power development in my country, the deep sea and other complex working conditions have put forward higher requirements for blades, and the high strength performance of carbon fiber materials will be able to adapt to more Harsh working conditions. In addition, lightweight blades can also reduce the difficulty of hoisting and transportation, which is helpful to reduce the cost of offshore wind power in the whole life cycle.

According to Song Dewu, Secretary of the Party Committee and Chairman of Jilin Chemical Fiber Group, in 2022, the global demand for carbon fiber for fan blades will account for 25.7 percent of the total global demand for carbon fiber, and the demand for carbon fiber for fan blades in China will also account for 23.5 percent of the overall demand for carbon fiber.

In Song Dewu's view, compared with aerospace, military technology and other fields, the carbon fiber product standards required for fan blades are different, and the technical cost is relatively lower. During the production process, different applications can be designed according to different properties, processes and costs. Performance and production process parameters, relatively fast to achieve mass production of carbon fiber.

In this case, China's carbon fiber industry has grown rapidly in the past two years. Data show that in 2022, the production capacity of domestic carbon fiber reached 112000 tons, and the supply exceeded the import volume for the first time.

Yuan Yuan, the main blade structure and blade product manager of Jinfeng Technology Co., Ltd., pointed out that in recent years, the planned production capacity of domestic carbon fiber has increased considerably, and the R & D and application scale of carbon fiber blades has also increased rapidly.

"As early as 2017, complete machine manufacturers have already started the application of carbon fiber blades in the international market, and multinational enterprises such as LM, Siemens Gamesa and Vestas have also produced 100-meter carbon fiber blades. With the vigorous development of the domestic offshore wind power market, in 2022, the development of domestic offshore large blades has achieved a comprehensive catch-up. At present, a large number of offshore wind turbine blades have been designed with carbon fiber in the domestic market. Domestic mainstream machine and blade manufacturers have also planned the next generation of offshore large megawatt units, and larger offshore wind turbine carbon fiber blades are also under development."

It is understood that at present, Mingyang Intelligent, Shanghai Electric, Dongfang Electric, Jinfeng Technology and other domestic mainstream complete machine manufacturers have started the test and production application of carbon fiber blades. Data show that since 2022, more than 70% of the newly developed and mass-produced offshore wind turbines in China have applied carbon fiber blades. Even in onshore wind turbines, some enterprises have begun to apply carbon fiber blades in small batches.

02 Automotive field Automotive industry will become a new field of carbon fiber applications

Previously, due to the high cost of carbon fiber, it was mostly used in specific fields such as wind power, aerospace, military industry, and sports cars. Nowadays, with the advancement of technology, carbon fiber not only has improved its function and strength, but also has a certain decline in cost.

Xu Lianghua, a professor at Beijing University of Chemical Technology, said that in recent years, the development situation of China's carbon fiber industry is very good. At present, three kinds of preparation systems have been formed: viscose-based, asphalt-based and polyacrylonitrile-based. The precursor preparation technology system is mainly based on dimethyl sulfoxide method, dimethylacetamide method and sodium thiocyanate method. Wet spinning, dry and wet spinning, small tow and large tow processes go hand in hand; high strength, high strength medium mold, high mold, high strength high mold complete product system.

With the continuous improvement of the performance of carbon fiber composites and the blessing of the "double carbon" policy, more and more automobile manufacturers are also focusing on this.

Ye Fuheng, deputy director of the National Key Laboratory of High-end Automotive Integration and Control of China FAW Research and Development Institute, believes that lightweight is one of the important ways to save energy and reduce emissions. The advantages of carbon fiber composite materials are suitable for many scenes such as automobile appearance parts, body structure, chassis structural parts, etc. It is an ideal material for automobile depth and lightweight.

"The right material should be used in the right place." Ye Fuheng said that the direction of multi-material hybrid materials will boost the industrialization and large-scale application of carbon fiber composite materials in the automotive industry. In the expected cost continues to explore, the industrial chain continues to complete the new market, the proportion of carbon fiber materials and the amount is expected to show an upward trend. At present, carbon fiber composite materials have been applied to BMW 7 Series, BMW iX, Audi A8, Weilai ES6, Chevrolet and other models.

As for how to realize the large-scale application of carbon fiber composite materials, Ye Fuheng said that this will start with the disruptive development and innovation of the whole industry chain linkage, and need the whole industry to cooperate and solve common technical problems, and further build a low-cost development path. At the same time, it is also necessary to focus on the transformation and upgrading of new energy vehicles, through integrated and functional development, to achieve low-cost and high-value coordination, and to create more than "light" high-value scenarios.

Ye Fuheng also said that advanced mass production manufacturing technology will contribute to the large-scale application of carbon fiber composite materials. The mixed use of continuous and discontinuous fibers can further expand the application range of carbon fiber composite materials and realize the composite of special-shaped solid parts. In addition, the data show that the recycled carbon fiber still has good mechanical properties and utilization value, which can not only be used in relatively low-demand application scenarios, but also reduce energy consumption, which will further improve the industrial chain.

In addition, Zhao Liang, technical director of Beijing Ketaike Technology Co., Ltd., also mentioned that the on-board hydrogen storage cylinder is also a new application scenario worth exploring for carbon fiber composite materials.

Source: China Chemical Industry News, Chengguan Publishing, China Energy News