Views: 111 Author: Site Editor Publish Time: 2021-12-10 Origin: Site
Before introducing electric vehicles, let's first learn the "traditional car", that is, the internal combustion engine car. It has a combustion chamber that converts the chemical energy of the fuel into heat energy and the kinetic energy that turns the wheels to drive the vehicle. Traditional cars have relatively long driving range and short refueling time. However, due to fuel consumption and related costs, as well as the impact on the environment, internal combustion engine vehicles are now facing major challenges. The main advantages of internal combustion engine vehicles are as follows:
●The vehicle can load a large amount of liquid fuel in the fuel tank
●The fuel has a high energy density, which is enough to travel hundreds of kilometers at one time.
●Refueling time is short.
Here are some disadvantages of traditional cars:
●The vehicle energy utilization efficiency is low, and the gasoline kinetic energy utilization rate is less than 20%.
●The energy loss is mainly due to the low efficiency of the engine and transmission system, which also consumes energy when idling.
●The massive use of hydrocarbon fuels is the chief culprit of environmental pollution and global warming.
An all-electric vehicle (AEV) uses electricity as its sole vehicle energy source. Since the vehicle is only powered by batteries or other energy sources, almost zero emissions can be achieved during operation.
Since it does not need to work with the internal combustion engine, there is no corresponding transmission and other mechanical transmission devices, so the vehicle structure is simpler, more reliable, and more effective. The energy utilization rate of electric vehicles can reach more than 90% (starting from the battery), while the utilization rate of the internal combustion engine is only 30%. In addition, motor-driven electric vehicles have low operating noise, and the electric energy used can be obtained from various energy sources. Many countries have begun to invest in the development of multi-style renewable energy (especially solar and wind energy), which has more advantages for the development of pure electric vehicles in the future.
The main advantages of pure electric vehicles are as follows
●The car is powered by the on-board power battery (which can be referred to as the power battery), and the high-efficiency drive motor drives the car.
●When braking, energy can be fed back to the power battery.
The disadvantages of pure electric vehicles are as follows:
●The power battery is the only energy source for electric vehicles, and its size is larger than that of hybrid vehicles or plug-in hybrid vehicles.
●Compared with traditional vehicles, the driving range is limited.
●It takes 7h to fully charge in level 2 mode.
Hybrid electric vehicles (HEV) combine traditional drive systems and energy storage systems, use internal combustion engines and electric motors to drive vehicles, and are an important bridge for the transition from traditional vehicles to pure electric vehicles. Hybrid cars are closer to traditional cars because they still rely on fossil fuels to drive them. The role of the motor and battery is to maintain engine efficiency, avoid idling and provide additional power, so the size is small. Therefore, hybrid electric vehicles can achieve better fuel economy (compared to traditional cars) and longer driving range (compared to pure electric vehicles).
The main advantages of hybrid vehicles are as follows:
●There are both power battery and fuel tank, both electric motor and internal combustion engine.
● Whether the motor is driven independently, or whether the internal combustion engine and the motor provide the vehicle driving torque together depends on the vehicle architecture.
●When idling, the air conditioner and other systems are running. Efficiency can be increased by 15% to 40%.
The main disadvantages of hybrid vehicles are as follows:
●Vehicles still rely heavily on internal combustion engines.
●The driving range of pure electric drive is usually limited to 40~100km.
●Much more expensive than traditional cars.
The main advantages of plug-in hybrid vehicles are as follows:
●The battery can be charged through the grid.
●Ideal means of transportation for short-distance commuting.
●There is no gasoline consumption or emission in pure electric mode.
The main disadvantages of plug-in hybrid vehicles are as follows:
●The battery used is larger and more expensive than HEV.
●It takes 4h to fully charge in Level2 mode.
In addition, unlike pure electric vehicles, which use all the energy in each cycle, the battery capacity output range of plug-in hybrid vehicles runs at 10% or less of the rated SOC (50%). In order to avoid overcharging, the SOC does not exceed 75. %, in order to avoid over-discharge, the SOC is not less than 25%. Therefore, only about half of the battery capacity of PHEV can be used.