1.Definition of new energy vehicles
According to the development policy of China’s automobile industry, the National Development and Reform Commission announced the “Administrative Rules for New Energy Vehicle Production Access”. Energy Vehicle Manufacturers and Products Access Management Rules (hereinafter referred to as the “Rules”). The “Rules” make a clear definition of new energy vehicles: new energy vehicles refer to the use of unconventional vehicle fuels as power sources (or the use of conventional vehicle fuels and the use of new vehicle power units), integrated vehicle power control and driving advanced technology, the formation of advanced technical principles, new technology, new structure of the car.
On April 18, 2012, at the executive meeting of the State Council, the “Energy Conservation and New Energy Vehicle Industry Development Plan (2012-2020)” was discussed and passed. At present, the focus is on promoting the industrialization of electric vehicles and plug-in hybrid vehicles, promoting the popularization of non-plug-in hybrid vehicles and energy-saving internal combustion engine vehicles, and improving the leveling technology level of China’s automobile industry. After nearly two years of discussions and soliciting opinions, the “Plan” has the greatest significance in that the government, the enterprise market and other parties have reached a consensus and placed equal emphasis on energy conservation and new energy.
2.Classification of new energy vehicles
According to the “Rules”, new energy vehicles include hybrid electric vehicles (HEV), pure electric vehicles (BEV, including solar vehicles), fuel cell electric vehicles (FCEV), hydrogen engine vehicles, natural gas vehicles and other new energy (such as high-efficiency vehicles) energy storage, dimethyl ether) automobiles and other categories of products.
1) Hybrid cars
A hybrid vehicle is a hybrid electric vehicle that is powered by more than one energy converter, that is, an electric vehicle that uses a battery and a secondary energy unit. The secondary energy unit is actually a prime mover that burns a certain fuel. Or power generator sets, currently, hybrid vehicles mostly use traditional fuel fuel engines mixed with electricity.
According to the different power system structure, HEVs can be divided into series hybrid vehicles (SHEV), parallel hybrid vehicles (PHEV) and hybrid hybrid vehicles (PSHEV). According to the different types of fuel, it can be divided into gasoline hybrid and diesel hybrid. At present, in the Chinese market, the mainstream of hybrid vehicles is gasoline hybrid, and diesel hybrid models in the international market are also developing rapidly.
Hybrid electric vehicle is the product of the combination of traditional internal combustion engine vehicle and electric vehicle. Its key technology is hybrid power system, and its performance is directly related to the performance of hybrid electric vehicle. The most prominent advantage of hybrid vehicles is their fuel economy. The maximum power of the internal combustion engine can be determined according to the average required power, so that the internal combustion engine can work under the optimal working conditions with low fuel consumption and less pollution, which generally saves fuel by 30% compared to traditional fuel vehicles. %~50%, and can also significantly reduce emissions; at the same time, the battery can easily recover the energy during braking and other working conditions; from the perspective of popularization, the existing gas station facilities can be used without new investment.
However, hybrid vehicles also have problems such as high price and long-distance high-speed driving that basically cannot save fuel. At present, China’s hybrid vehicle technology is developing rapidly, and some models are already in the mature stage of technology.
2) Pure Electric Vehicles
A pure electric vehicle refers to a vehicle that is powered by an on-board power supply and driven by a motor, and meets the requirements of road traffic and safety regulations.
Pure electric vehicles are completely driven by rechargeable batteries, and their basic structure is not complicated. The motor generator and on-board battery are the key components, and the battery is the most critical. The difficulty lies in the power storage technology.
Since electricity can be obtained from a variety of primary energy sources, there is no need to worry about the depletion of energy sources. Therefore, pure electric vehicles have broad application prospects. At the same time, pure electric vehicles have no pollution, low noise, and high energy efficiency. And applications have become a “hot spot” in the automotive industry. At present, the energy stored per unit weight of the battery is too small, and the mileage after charging is not ideal; the battery with high reserve has a short service life, and it is difficult to achieve commercial operation due to the high cost of use due to the lack of economic scale.
For the process of electric vehicle industrialization, the biggest obstacle at present is infrastructure construction and price. Compared with hybrid vehicles, electric vehicles require more infrastructure support, which requires government investment and related enterprises to cooperate and jointly build, so that it is possible to popularize and promote on a large scale. In recent years in China, after the development of pure electric vehicle technology such as lead-acid batteries is relatively mature, other batteries have also developed by leaps and bounds.
3) Fuel cell electric vehicles
A fuel cell electric vehicle is a new type of vehicle that uses a fuel cell to directly convert the chemical energy in the fuel into electrical energy for power driving.
Compared with hybrid electric vehicles, fuel cell electric vehicles do not carry out the combustion process of fuel at all, but directly convert chemical energy into electrical energy through batteries, which are driven by electric motors. Compared with pure electric vehicles, the power source of fuel cell vehicles is mainly fuel cells, not batteries. The energy conversion efficiency of the fuel cell is 2 to 3 times higher than that of the internal combustion engine. The chemical reaction process of the paste cell does not produce harmful products and has low noise. Therefore, from the perspective of energy utilization and environmental protection, fuel cell electric vehicles are an ideal vehicle, representing the future development direction of clean vehicles.
The fuels used in fuel cell electric vehicles include hydrogen, methanol, gasoline, diesel, etc., and liquid hydrogen with high energy density is widely used internationally. In recent years, although significant progress has been made in fuel cell technology internationally, there are still technical challenges in the development of fuel cell vehicles, such as the integration of fuel cell stacks, vehicle integration, industrialization, and commercialization. The research level in China’s fuel cell electric vehicle field is almost the same as that of developed countries. Relevant experts pointed out that China is fully capable of catching up with the world’s advanced level in this field.
4) Hydrogen engine car
A hydrogen engine vehicle is a vehicle that is modified on the basis of an existing engine to generate energy from the mixed combustion of hydrogen (or other auxiliary fuel) and air to obtain power.
In addition to the advantages of no pollution and low emissions, hydrogen engine vehicles also have some special advantages, such as lower requirements for hydrogen,
High combustion performance, mature internal combustion engine technology, etc. However, hydrogen engine vehicles are now faced with two major problems: hydrogen production and liquid hydrogen storage. Whether these two problems can be effectively solved will determine the development prospects of hydrogen engine vehicles.
5) Natural gas vehicles
Natural gas vehicles are vehicles fueled by natural gas, also known as “blue power” vehicles. According to the chemical composition and form of natural gas, it is divided into three types: compressed natural gas (CNG), liquefied natural gas (LNG) and liquefied petroleum gas (LPG). Because natural gas vehicles use natural gas as fuel, they have the characteristics of low pollution, low cost and high safety, but the power performance is low and it is not easy to carry. The pipeline for natural gas transportation involves many factors such as urban construction planning, capital investment and environmental safety, and the cost is very high. China is rich in natural gas resources, and natural gas vehicle technology has developed rapidly. In areas rich in natural gas resources, natural gas vehicles are relatively popular.
6) Other new energy vehicles
In addition to the new energy vehicles introduced above, there are also new energy vehicles fueled by organic substances, such as alcohol and ether. The fuel used in ethanol vehicles is ethanol gasoline. The technology of ethanol vehicles is relatively mature, and the traditional internal combustion engine can be modified to adapt to different ethanol gasoline fuels. Ethanol vehicles are developing rapidly in countries rich in ethanol resources such as the United States and Brazil, but are still in their infancy in China.
DME automobiles use DME as the fuel for compression ignition engines. There are two ways to use them: one is to use DME as an ignition promoting substance; the other is to directly burn pure liquid DME. Important progress has been made in the development of DME automotive technology in China. For example, SAIC Motor Group has successfully developed DME city bus and started trial operation.