Introduction to pure electric vehicles and plug-in hybrid electric vehicles
Pure Electric Vehicle (BEV)
A pure electric vehicle is a vehicle powered by an on-board power supply and driven by a motor to drive wheels, which meets the requirements of road traffic and safety regulations. Pure electric vehicles are completely driven by rechargeable batteries. The key components are motor generators and batteries, while the application of pure electric vehicles is limited by power storage technology. Figure 1 shows a schematic diagram of a simple structure of a pure electric vehicle.
Pure electric vehicles have broad application prospects and have the following advantages: ① No pollution. Electric vehicles use power battery packs to provide energy sources for power motors, and no exhaust gas is generated during operation, which effectively improves the pollution of the atmosphere caused by vehicle exhaust. ②Low noise. Electric cars use motors to drive cars, reducing the noise generated by traditional cars using internal combustion engines. ③ High energy efficiency and diversification. Pure electric vehicles use power batteries, which have high energy conversion efficiency and can realize braking energy recovery. In addition, the electricity charged to the battery can be converted from coal, solar, wind, and nuclear energy, effectively reducing dependence on oil. ④Simple structure, easy to use and maintain. Compared with internal combustion engine vehicles, electric vehicles have a simpler structure, fewer transmission parts, and less maintenance work.
However, pure electric vehicles also have the following shortcomings compared with traditional internal combustion engine vehicles: ①Short driving range. Affected by battery capacity and cost, most pure electric vehicles currently have a driving range of 150-200km. Compared with internal combustion engine vehicles, the driving range of pure electric vehicles is an important factor restricting their development. ②Long charging time. At present, the battery fast charging technology is not yet mature. It usually takes 1~2h to fully charge the battery using high-power charging piles, and 6~12h to charge the battery using the home power grid. ③The supporting facilities are not perfect. Under the situation that the construction of domestic charging facilities is lagging behind, charging is a major problem facing electric vehicles, and the lack of public charging piles is also the reason that affects the development of electric vehicles.
Plug-in hybrid electric vehicle (PHEV)
Plug-in hybrid electric vehicle is a new type of hybrid electric vehicle. Different from the traditional hybrid power that combines gasoline power and electric drive, the plug-in hybrid power drive principle and drive unit are the same as electric vehicles. The only difference is that the vehicle is equipped with an engine. Plug-in hybrid vehicles have more ways to obtain electrical energy. In addition to providing electrical energy through internal combustion engines, they can also be charged through charging piles or household 220V power sources. Plug-in hybrid electric vehicles are a further development of hybrid electric vehicles to pure electric vehicles, and are a bridge connecting two generations of products. The structure of the plug-in hybrid vehicle is shown in Figure 2.
The plug-in hybrid electric vehicle has the following advantages: ① It has a longer driving capacity in electric mode, and relies on electric motor drive in urban roads to achieve energy saving and low emission. In long-distance or high-speed sections, internal combustion engines are often used to improve power and transmission efficiency. ②You can use charging piles and household 220V power supplies to charge the vehicle, and use the “peak-to-valley difference” to charge at night, which can reduce the cost of using the vehicle. ③The capacity of PHEV on-board battery pack is usually 6~10kW·h, which is less than 1/2 of pure electric vehicles, but the driving range is 3~5 times higher than that of ordinary hybrid models.
Because plug-in hybrid electric vehicles use internal combustion engines and batteries as power sources, they cannot completely get rid of their dependence on petroleum. The vehicle structure is complex and the cost is relatively high.