Since the 21st century, China’s automobile industry has developed rapidly and has formed an industrial system with complete types and complete supporting facilities. However, the problems of energy, environmental protection, and transportation caused by the huge car ownership have become increasingly prominent. Therefore, the development of new energy vehicles has been vigorously developed and the promotion of new energy vehicles has been accelerated. The industrialization process of energy vehicles is an inevitable choice for my country to effectively respond to the energy crisis and environmental challenges and realize the sustainable development of China’s auto industry. It is also an important measure to seize strategic opportunities, shorten the gap with advanced countries, and achieve leap-forward development of the auto industry.
On April 18, 2012, the State Council discussed and passed the “Energy-saving and New Energy Automobile Industry Development Plan (2012-2020)” (hereinafter referred to as the “Plan”). The main strategic direction of the transformation of the automobile industry is to focus on breakthroughs in power batteries, motors and electronic control technologies, and focus on promoting the industrialization of pure electric vehicles and plug-in hybrid electric vehicles. Improve China’s automobile fuel economy level; strengthen independent innovation, master key core technologies for energy-saving and new energy vehicles, and enhance the ability of independent industrial development. The overall goal of the plan: By 2020, the cumulative production and sales of new energy vehicles will reach 5 million; the energy density of the power battery system will reach 200w·h/kg, and the cost will be reduced to 1.5 yuan per watt-hour; medium and heavy hybrid passenger vehicles will account for More than 50% of the annual production and sales of passenger cars; the overall level of automobile fuel economy is in line with the international advanced level, the average fuel consumption of new passenger cars has dropped to 5.0L/100km, and the fuel consumption of energy-saving passenger cars has dropped to 4.5L /100km or less.
- The definition of new energy vehicles
China’s commitment to Xinyuan Motors originated from the “Regulations on the Entry of New Energy Vehicle Manufacturers and Products” (hereinafter referred to as the “Regulations”) promulgated by the Ministry of Industry and Information Technology (hereinafter referred to as the Ministry of Industry and Information Technology) on January 6, 2017. The article clearly states: New energy vehicles refer to vehicles that use new power systems and are driven entirely or mainly by new energy sources.
- Classification of new energy vehicles
The types of new energy vehicles mainly include pure electric vehicles, hybrid electric vehicles (including extended range), and fuel cell electric vehicles.
(1) Pure electric vehicles.
A pure electric vehicle (Battery Electric Vehicle, BEV) is a kind of battery (such as lithium-ion battery, nickel-hydrogen battery or lead-acid battery) as a vehicle-mounted energy storage power source, which provides electric power to the motor to drive the motor to run, and is driven by the motor A car that runs on wheels and meets the requirements of road traffic and safety regulations.
(2) Hybrid electric vehicles.
Hybrid Electric Vehicle (Hybrid Electric Vehicle, HEV) refers to the use of two or more different power sources to drive the vehicle. The driving power of the vehicle is based on the actual driving state of the vehicle. A single power source alone or multiple power sources Provided together. Its mixing forms include oil-electricity, gas-electricity and oil-gas mixing, with oil-electricity mixing as the mainstay. A hybrid electric vehicle is a vehicle driven by a gasoline (diesel) engine and an electric motor alone or together. It combines an internal combustion engine, an electric motor, and an energy storage device (battery). Good matching and optimal control between them can be sufficient Taking advantage of the advantages of internal combustion engine and electric motor and avoiding their own shortcomings, it is the most practical development of low-emission, low-fuel consumption vehicles.
According to different power coupling modes, oil-electric hybrids can be divided into series hybrids, parallel hybrids and hybrid hybrids.
①Tandem hybrid power. In the series hybrid power system, the engine directly drives the generator to generate electricity. The generated electrical energy is transmitted to the battery through the power control unit, and then transmitted to the electric motor from the battery to convert into kinetic energy, and finally the car is driven by the transmission mechanism. In this connection mode, the battery is like a reservoir, but the object of regulation is not water, but electricity. The battery adjusts between the energy produced by the generator and the energy required by the electric motor to ensure the normal operation of the vehicle. The advantage of this system is that the driving range is longer; the disadvantage is that the power route is longer, and the transmission efficiency is lower due to multiple energy conversions. It is mainly used in city buses. The application brands include Zhongtong, Yutong, and Kinglong.
②Parallel hybrid power. The engine and electric motor of the parallel hybrid power system drive the car together, or they can work alone, with the electric motor as auxiliary power. The advantage of this system is its simple structure and low cost; its disadvantage is that the engine efficiency cannot be fully utilized. For example, Honda’s IMA system, the application models are Honda Accord and Civic.
③Hybrid hybrid power. , The key to the series hybrid power system is that the engine and the electric motor share a set of mechanical transmission mechanism. The two are connected by a power distribution device (clutch or planetary gear mechanism) to comprehensively adjust the speed relationship between the engine and the electric motor. Compared with the parallel hybrid power system, the hybrid system can adjust the power output of the engine and electric motor more flexibly according to the working conditions. The advantages of the system are ideal for energy saving; the disadvantages are complex structure, high cost, and difficult control. For example, the THS of Toyota Prius.
According to the possibility of external charging, hybrid electric vehicles are generally divided into conventional hybrid electric vehicles and plug-in hybrid electric vehicles.
Plug-in Hybrid Electric Vehicle (PHEV) is based on conventional hybrid vehicles and has the basic functional characteristics of pure electric vehicles. The control principle is more complicated than that of pure electric vehicles. It works mainly in pure electric mode, and there are three sources of battery power: ①Slow charging through household 220V power supply or fast charging through special charging piles, connecting to the on-board charging port to charge the battery; ②When the battery power is lower than the set value and When it cannot be charged in time, the gasoline (diesel) engine drives the generator to generate electricity to recharge the battery; ③When decelerating and braking, the motor reverses as a generator to recharge the battery.
Plug-in hybrid electric vehicles are mainstream development models at home and abroad, such as Pentium B50 and BYD Qin.
In addition, hybrid electric vehicles also include extended-range electric vehicles. Extended-range electric vehicle (Extended-Range Electric Vehicle, REV) is an electric vehicle driven by pure electricity with two functions: ground charging and on-board power supply. Its working mode is divided into three types, namely pure electric mode, extended range mode and hybrid power mode. It has the characteristics of both pure electric vehicle and hybrid electric vehicle. Its power system structure is similar to that of series hybrid electric vehicle.
The definition of extended-range electric vehicle given by General Motors’ EDTate and others is as follows: the vehicle can reach all its power performance in pure electric mode, and when the on-board rechargeable battery cannot meet the driving range requirements, turn on the on-board auxiliary The power generation device (range extender) provides electrical energy for the power system to extend the driving range. According to this definition, the essence of the extended-range electric vehicle is a pure electric vehicle, but a gasoline engine + generator (range extender) is installed on the pure electric vehicle. Typical models such as GAC Trumpchi GA5. GAC Trumpchi GA5 prioritizes the use of pure electric mode, and the pure electric driving range (constant speed 60km/h) is 80km, and when the battery power is lower than the set value, the range extender participates in power generation.
(3) Fuel cell electric vehicles.
Fuel cell electric vehicle (Fuel Cell Electric Vehicle, FCEV) power battery is a fuel cell, which generates electrical energy through electrochemical reaction and transmits it to the electric motor to drive the vehicle. Fuel cell electric vehicles are essentially pure electric vehicles. The main difference is that the working principles of the two power batteries are different, and the fuel cell electric vehicle has a short hydrogenation time and a long driving range for one hydrogen refueling. Fuel cell electric vehicles currently mainly use proton exchange membrane fuel cells, which convert chemical energy into electrical energy through the electrochemical reaction of hydrogen and oxygen. The hydrogen storage methods can be divided into high-pressure gaseous hydrogen storage, low-temperature liquid hydrogen storage, metal hydride solid-state hydrogen storage, and carbon nanotube adsorption hydrogen storage. A typical model of fuel cell electric vehicles-Toyota Mirai.
(4) Other new energy vehicles.
Other new energy vehicles include vehicles that use high-efficiency energy storage such as solar cells, supercapacitors, and flywheel batteries.