Future Development Trends Of Electric Vehicle Battery Technology And Materials

Electric vehicle technology roadmap

Electric vehicles are vehicles that mainly use batteries as the power source and are driven entirely or partially by electric motors. They are high-tech products involving multiple disciplines such as mechanics, electronics, electricity, and microcomputer control. According to the current technical status and vehicle driving principles, electric vehicles can be divided into three types: hybrid electric vehicles, pure electric vehicles and fuel cell electric vehicles. With technological advancement and application development, the classification of electric vehicles will also undergo new changes. For example, plug-in electric vehicles as a branch are gradually expanding their influence and will soon become an important force in the history of electric vehicle development.

1. Hybrid Electric Vehicle (HEV)

In the past ten years, due to the relatively mature technology and obvious energy-saving and environmental protection effects, hybrid electric vehicles have developed rapidly and, with the encouragement of preferential policies in various countries, have gradually entered the stage of commercial promotion and application. Japanese hybrid electric vehicle models, represented by Prius and Civic, have absolute advantages in the market and occupy a dominant position in technology and market. In recent years, major European and American automobile manufacturers have also launched hybrid vehicles with their own characteristics. The Japanese-dominated pattern is being broken. It is foreseeable that hybrid electric vehicles will gradually become the mainstream of major automobile companies in 2 to 3 years. Competing models.

Hybrid electric vehicles mainly refer to vehicles that add an auxiliary power system consisting of an electric motor and a power battery to a traditional internal combustion engine vehicle, and the system performs power balancing, coupling, energy regeneration and storage and other functions. Depending on the degree of electromechanical coupling, control strategy and road traffic conditions, the fuel saving rate ranges from 10% to 40%.

2. Plug-in Hybrid Electric Vehicle (PHEV)

Plug-in electric vehicles are also called externally rechargeable hybrid electric vehicles. The vehicle charges the power battery equipped in the system by connecting to household power supply (110V/220V) or dedicated power supply (380V/500V). After charging, it can only The battery-driven electric motor is used to drive the electric vehicle in pure electric mode. After the remaining power of the rechargeable battery is used up, the car can start the internal combustion engine and drive in parallel or series hybrid mode. PHEV realizes a true gasoline-electric hybrid, which can be "refueled" or "charged". It can achieve zero-emission driving with a longer mileage and is cleaner than conventional hybrid power.

PHEV takes into account the advantages of pure electric vehicles and conventional HEV. It is a clean, energy-saving and easy-to-use vehicle that is feasible at this stage. It is a transitional technical solution from HEV to BEV. The starting point for plug-in hybrid vehicles is to drive in pure electric mode.

3. Electrical Vehicle (EV for short)

A pure electric vehicle is also called a Battery Electrical Vehicle (BEV). Its power system is mainly composed of a power battery and an electric motor. It obtains power from the power grid (or replaces the battery) and provides electric energy to the electric motor through the power battery. Drive the car.

The main advantages of pure electric vehicles are: zero emissions, low vibration and noise, high energy efficiency, and the ability to use cheap "off-peak power" from the power grid for charging at night, which plays a role in smoothing the peak and valley differences in the power grid. The main disadvantages of pure electric vehicles: first, the social cost of investing in charging infrastructure is high, and the popularization of charging stations requires a large amount of social capital investment; second, the driving range is short, the power battery is expensive, and the battery capacity and lifespan also need to be improved.

At present, pure electric vehicles have been commercially promoted and applied in the United States, Japan, Europe and other countries and regions, focusing on special municipal vehicles (postal transport vehicles, sanitation vehicles, etc.), fixed-line buses, official fleet vehicles and Private cars and other fields. Currently, France ranks among the top in the world in terms of popularity and ownership of electric vehicles.

Technically, contemporary pure electric vehicles show the following trends: power system integration and optimization technology continues to improve, and energy saving effects are significant; high-performance lithium-ion batteries and nickel-hydrogen batteries replace traditional lead-acid batteries; efficient integrated electric drive systems replace Traditional DC motors; the widespread application of electric auxiliary systems has improved the energy utilization efficiency and vehicle performance of the entire vehicle; the application of network systems has promoted the modularization and intelligence of electric vehicles; lightweight technology and electrical structural safety technology have been System application.

Since 2009, China has set off an upsurge in the research and development of pure electric vehicles. From pure electric mini cars to pure electric sedans, pure electric buses and pure electric special vehicles, product prototypes have been launched one after another. Traditional automobile manufacturers are preparing to transform. Electric light vehicles, auto parts companies and even other companies not related to the automobile industry often invest tens or even hundreds of millions of yuan, and demonstrations of pure electric vehicles are widely carried out in various places. The industrialization of pure electric vehicles has ushered in a spring in China.

4. Fuel Cell Electrical Vehicle (FCEV)

A fuel cell electric vehicle is a vehicle that uses hydrogen and oxygen in the air to generate electrical energy through an electrochemical reaction in a fuel cell under the action of a catalyst and serves as the main power source to drive the vehicle. Its power system is mainly composed of a fuel cell engine, a fuel tank (hydrogen bottle), an electric motor/generator, a power battery, etc. It uses fuel cell power generation as the main energy source and drives the vehicle through the motor.

The main features of fuel cell electric vehicles: high energy conversion efficiency. The energy conversion efficiency of fuel cells can be as high as 60% to 80%, which is 2 to 3 times that of internal combustion engines; zero emissions and no environmental pollution. The fuel of the fuel cell is hydrogen and oxygen, and the product is clean water; hydrogen fuel comes from a wide range of sources and can be obtained from renewable energy sources and does not rely on petroleum fuel.

The research and development model of fuel cell vehicles is currently conducted by industry, academia and research institutes under the leadership of the government, and transnational cooperation is actively carried out around the world. The implementation of major national research plans and cooperative R&D projects has greatly promoted the research and development process of global fuel cells and fuel cell vehicles. Recently, the newly launched fuel cell vehicles in the world have shown excellent performance and have made great progress in vehicle reliability, cost control and other aspects.