Comprehensive Interpretation of Advanced Composites for Electric Vehicles and Automotive Industry
Composite materials refer to materials composed of two or more different materials. Typically, metals, ceramics, or polymer materials can be used as the main matrix materials. Compared with traditional materials, most composite materials are designed with a focus on high specific strength, lower weight, and relatively high corrosion resistance. Higher strength, higher fatigue strength, better physical properties, lighter weight, and better surface finish are the main advantages of composite materials.
In the automotive industry, composite materials are lighter than the most commonly used metals. Carbon fiber-based composites are the highest-performing polymer composites used in cars, aerospace, military defense, and sports equipment. In traditional cars, metal constitutes the central structure, while some internal parts are made of composite materials. In recent years, carbon fiber composites have been considered the most suitable material for reducing vehicle weight, although it may differ from traditional metals and is expensive.
Compared to aluminum alloys, composite materials can see more enhancements in mechanical properties, microstructure, and surface morphology. Generally, the application of composite materials in the automotive industry is classified as special materials. In electric vehicles, steel and cast iron account for about half of the materials by weight; aluminum alloys make up about 9% of the total, plastics account for 11%, and rubber makes up 3%. Nowadays, industries are focusing on the use of renewable resources and further utilizing recyclable, environmentally friendly, and less hazardous materials with global impact.
Reducing emissions and fuel consumption are major challenges faced by the automotive industry. Due to energy production relying on carbon-based fossil fuels, a large amount of greenhouse gases are emitted into the environment. With the continuous increase in global electricity consumption, there has been an increase in energy demand over the past few decades. Due to the high cost of fuel, and also considering environmental degradation, consumers are motivated to choose electric vehicles. The demand and motivation for using electric vehicles have increased in many countries around the world. Electric vehicles are alternatives to diesel, gasoline, and other fossil fuel vehicles because they use lithium-ion batteries, which offer the convenience of mixed charging and are lighter in weight, as most components are made from composite materials to improve vehicle fuel efficiency. Additionally, they may not require most of the components needed for traditional vehicles driven by fossil fuels. Some ride-hailing companies are focusing on replacing their internal combustion engine fleets with electric vehicles.
To address energy efficiency issues, researchers suggest using lightweight materials to replace automotive parts, which can reduce vehicle weight while enhancing fuel economy. For every 10 kilograms reduction in vehicle weight, carbon emissions will decrease by 1 gram per kilometer, thereby reducing fuel consumption. The lightweight solution is gradually becoming an important method because it has proven effective in reducing fuel demand and emissions.
Automotive lightweighting focuses on reducing vehicle mass through alternative materials and redesigning components, while maintaining the size of the vehicle and further ensuring consumer needs. In the design of internal combustion engine vehicles, researchers have employed various technologies to study the advantages of lightweight materials compared to traditional ones. The result of the integration of electric vehicles and lightweight design is a reduction in the vehicle's environmental impact. Moreover, the use of lightweight materials in electric vehicles is foreseeable, as it can improve performance by reducing mass, such as driving range and battery size control (as shown in the figure below).
Electric Vehicle Structural Component Composition
Composite materials are considered potential candidate materials for manufacturing lightweight components, and efforts have been made to reduce vehicle weight while also developing cost-effective methods of producing lightweight materials such as Carbon Fiber Reinforced Plastics (CFRP). Compared to traditional materials, CFRP possesses high strength, low weight, good vibration resistance, high stiffness, and higher fatigue and corrosion resistance.
In recent years, although automotive composite material technology has received widespread attention and research, employment in the automotive industry still lags behind the aerospace industry. Therefore, further development and advancement are needed to meet the growing demand for electric vehicles. The following chart shows the classification of different vehicle types. Combining current statistics from the electric vehicle and automotive industries, the estimated value of the international passenger electric vehicle market in 2020 was approximately $120.81 billion, with an expected compound annual growth rate of about 32.5% from 2021 to 2028.
Different vehicle categories
In 2020, global car sales were approximately 3 million units, marking an increase of nearly 40% from 2019. In the same year, electric vehicles in China accounted for about 30% of global sales. Since 2021, the United States has offered more than 15 different models of battery-electric vehicles (BEV). Compared to plug-in hybrid electric vehicles (PHEV), BEVs are expected to see higher growth due to their range issues.
In the battery-electric vehicle niche, the upgraded version of the Tesla Model S was the most common, with the supplier achieving over 70% of sales in the battery-electric vehicle domain in 2020. The highest compound annual growth rate in the PHEV industry could exceed 32% within the forecast period. These advancements can be attributed to the recommendations put forward by industrialized and developing economies' governments to promote the use of electric vehicles.