After three generations of development, the battery for electric vehicles has made a breakthrough.
1 generation is lead-acid battery, and at present it is mainly valve-regulated lead-acid battery (VRLA). Because of its high specific energy, low price and high rate discharge, it is the only battery for electric vehicles that can be mass-produced.
The second generation is alkaline battery, which mainly includes Ni-Cd, Ni-MH, Na-S, Li-ion and Li-polymer batteries. Its specific energy and specific power are higher than those of lead-acid batteries, thus greatly improving the power performance and driving range of electric vehicles, but its price is higher than that of lead-acid batteries.
The third generation is a fuel cell-based battery, which directly converts the chemical energy of fuel into electric energy, with high energy conversion efficiency, high specific energy and specific power, and can control the reaction process, and the energy conversion process can be carried out continuously. It is an ideal automobile battery, and some key technologies have yet to be broken.
The fuel cell widely used in electric vehicles is a kind of fuel cell called proton exchange membrane (PEMFC), which uses pure hydrogen as fuel and air as oxidant. It does not go through the heat engine process and is not limited by thermal cycle, so the energy conversion efficiency is high, which is 2 ~ 3 times that of ordinary internal combustion engines. At the same time, it also has the characteristics of low noise, no pollution, long service life, fast starting, large specific power and adjustable output power at any time, which makes PEMFC very suitable for being used as the power source of vehicles. The United States and Canada are the main areas of fuel cell research and development and demonstration. With the support of DOE, DOT and EPA, fuel cell technology has made great progress. General Motors, Ford Motor Company, Toyota, Daimler Benz, Nissan, Hyundai and other vehicle companies have all participated in the technical demonstration operation of fuel cell vehicles in California. It also cultivated the project lane plan launched by General Motors in the autumn of 2007, such as UTC in the United States and Ballad in Canada, and delivered 65,438+000 Chevrolet Equinox fuel cell vehicles to consumers. In 2009, the total mileage reached 654.38+600,000 kilometers. In the same year, GM announced the development of a new generation of hydrogen fuel cell system. Compared with the fuel cell system on Chevrolet Equinox fuel cell vehicle, the volume of the new generation hydrogen fuel cell is reduced by half, the weight is reduced by 100 kg, and the platinum consumption is only 1/3 of the original. The platinum consumption of GM's new generation fuel cell vehicles has been reduced to 30 g. According to the current international market price, the platinum consumption of 300~400 yuan /g, 1000 kW fuel cell costs about 10000 RMB, which greatly reduces the cost of fuel cells. It is predicted that by 20 17 years, the platinum consumption of 100 kW fuel cell engine will be reduced to/kloc-0 ~15 g, reaching the platinum consumption level of traditional three-way catalytic converter of gasoline engine.
In 2006, the United States specially launched the National Fuel Cell City Bus Program (NFCBP), and carried out extensive vehicle research and development and demonstration work. 20 1 1 year, the service life of American fuel cell hybrid buses exceeds 1. 10000 h, and the United States has also conducted a large-scale demonstration of fuel cell hybrid forklifts. By 20 1 1, there are about 3,000 fuel cell forklifts in the United States with a service life of12,500 h. Fuel cell forklifts are used in indoor space, which has the advantages of low noise and zero emission. The sixth framework plan (2002-2006) and the seventh framework plan (2007-20 12) have been completed in the demonstration plan of fuel cell buses in Europe, aiming at breaking through some key technical difficulties in the development of fuel cells and hydrogen energy. In Cute (Clean Urban Transport in Europe), with the support of Clean Urban Transport in Europe and other related projects in the European Union, cities have carried out demonstration operation of fuel cell buses, and this year, a new plan CHIC (Clean Hydrogen in European Cities) has been implemented. Including Amsterdam, Barcelona, Hamburg, London, Luxembourg, Madrid, Porto, Stockholm, Stuttgart, Iceland and Perth, Australia, Europe has made great progress in the reliability and cost control of fuel cell vehicles.
In Germany, in June, 20 12, major automobile and energy companies and the government promised to establish an extensive national hydrogen fuel filling network, and supported the formulation of an incentive plan, that is, by 20 15, 50 hydrogen filling stations will be built nationwide to provide hydrogen service for 5,000 fuel cell vehicles nationwide [7]. Daimler-Benz launched the global exhibition of fuel cell vehicles on 20 1 1, which proved that the performance of fuel cell vehicles has reached the performance of traditional vehicles and has the ability of industrial promotion. Daimler Group participated in the project "Hyfleet: Cute (2003-2009)". Thirty-six Mercedes-Benz Citaro fuel cell buses have been operated by 20 transport operators, with the operation time exceeding 6.5438+0.4 million hours and the mileage exceeding 2.2 million kilometers. However, the life span of the first generation pure fuel cell buses is only 2 000 h, and the economy is poor. In 2009, Daimler Group began to launch the second generation fuel cell bus driven by wheel-side motors, with the main performance reaching the international advanced level, greatly improving the economy and the fuel cell durability reaching 654.38+0.2 million h. ..
The fuel cell developed by Siemens in Germany has been successfully applied to the German 2 14 submarine (hydrogen-oxygen type) [1 1]. In 2007, Daimler Benz of Germany, Ford Motor Company of the United States and Ballard Company of Canada jointly established AFCC (Automotive Fuel Cell Cooperation) to develop and promote automotive fuel cells. At the beginning of 20 13, BMW decided to cooperate with Toyota Motor Corporation, which ranked first in fuel cell technology, and Toyota provided fuel cell technology to BMW. From a global perspective, Japan and South Korea lead the world in fuel cell research and development, especially Toyota, Nissan and Hyundai Motor Company, and gradually surpass the United States and Europe in the durability, life and cost of fuel cell vehicles. Toyota 2008 FCHV-Adv was successfully started at -37℃ in the actual test. The mileage of a hydrogenation trip reaches 830km, and the hydrogen consumption per unit mileage is 0.7 kg/( 100 km), which is equivalent to 3L/( 100 km) of gasoline, as shown in Figure 3 [12]. 20 13 10, Toyota exhibited a fuel cell concept car which is scheduled to be put on the market in 20 15 at the 43rd Tokyo Auto Show. As the technical core, fuel cell stack has achieved the highest power density of 3 kW/L in the world at that time. The fuel cell stack cancels the humidification module, which not only reduces the cost, weight and volume of the vehicle, but also reduces the heat capacity of the fuel cell, which is beneficial to the rapid cold start of the fuel cell at low temperature. As shown in Figure 5, it is FCHV-Adv of Toyota.
At present, Toyota Motor Corporation is preparing for the industrialization of fuel cell vehicles while expanding hybrid vehicles, and plans to launch a new generation of fuel cell vehicles for mass production in 20 15. 20 16 Production of New Generation Fuel Cell Bus (in cooperation with Hino). Similar to Toyota Motor Corporation, Nissan Motor Corporation has also invested heavily in the research and development of fuel cell stacks and automobiles. 20 1 1, the daily fuel cell stack has a power of 90 kW and a mass of only 43 kg. In 20 12, the power density of stack developed by Nissan Motor Company reached 2.5 kW/L, which was the highest level in the world at that time [65438+]. In addition, the newly developed FCX Clarity fuel cell vehicle of Honda can be started smoothly at -30℃ with a continuous driving range of 620 km[ 15]. In 20 14, the power density of the new generation fuel cell stack announced by Honda also reached 3 kW/L, and Hyundai Korea began to develop fuel cell vehicles in 2002. In 2005, it assembled 32 sport utility vehicles (SUVs) with Ballard's stack. In 2006, the first generation of self-developed stack was launched, and 30 SUVs and 4 buses were assembled for demonstration operation. During 2009-20 12, the second generation reactor was developed and 100 SUV was assembled. Demonstrations and tests were started in China, which improved the performance of the reactor. In 20 12, the third generation fuel cell SUV and bus went on the market, and the global demonstration began; In 20 13, Hyundai announced that it would put into production the fuel cell SUV (Hyundai ix35) two years ahead of schedule, taking the lead in entering the small-scale production stage of fuel cells in the world. The SUV adopts 100 kW fuel cell, 24 kW lithium ion battery and 100 kW motor. The 70 MPa hydrogen bottle can store 5.6 kg of hydrogen. Under the cycle condition of NEDC, the driving range is 588 km and the top speed is160 km/h. With the support of the national "863" high-tech project, the "Tenth Five-Year" major scientific and technological project of electric vehicles and the "Eleventh Five-Year" major project of energy-saving and new energy vehicles, and through the efforts of the joint R&D team in Industry-University-Research, China has made great progress in the technical research and development of fuel cell vehicles, and initially mastered the core technologies of complete vehicles, power systems and core components. The technical platform of fuel cell vehicle and fuel cell city bus power system with independent intellectual property rights has been basically built, and the supporting research and development system of key components such as fuel cell engine, power battery, DC/DC converter, drive motor and hydrogen supply system has been initially formed, realizing the power system of 100 vehicles and the production capacity of the whole vehicle. China fuel cell vehicles are in the stage of commercial demonstration, operation, assessment and application, and have been used in the scale of fuel cell vehicles for the Beijing Olympic Games, the scale of fuel cell vehicles for the Shanghai World Expo, the bus demonstration of fuel cell cities in UNDP (United Nations Development Programme), "Ten Thousand Vehicles in Ten Cities" and the Guangzhou Asian Games.
Demonstration applications such as Shenzhen Universiade have achieved good social benefits. China fuel cell vehicle adopts a unique technical scheme of "electric-electric hybrid" power system platform, which has the technical characteristics of "vehicle adaptation of power system platform, power control of electric-electric hybrid energy, on-board high-pressure hydrogen storage system and purification and utilization of industrial by-product hydrogen". Based on the research and development of the new generation fuel cell vehicle in the 11th Five-Year Plan, combined with the change of vehicle platform, the power system layout is flat, and the hydrogen subsystem, air subsystem and cooling system of the fuel cell engine are modularized and distributed, which increases the flexibility of the power system and the vehicle and obviously improves the ergonomic performance of the vehicle. At the same time, the control unit of power system, which integrates DC/DC converter, DC/ AC controller, electric air conditioner, low-voltage converter and other power components, is optimized, which improves the modularity, facilitates centralized handling of electromagnetic compatibility, system heat dissipation and electrical safety, and embodies electrification.
The direction of integrated design of automobile power system. Compared with the power system of fuel cell vehicles in the tenth five-year plan, the performance of the new generation power system has been further optimized and improved. The main performances are as follows: the power of fuel cell engine is increased from 40 kW to 55 kW; ; The capacity of power battery is reduced from 48 kWh to 26 kWh; The motor power is increased from 60 kW to 90 kW; ; The motor controller (DC/AC) power is increased by 35%, and the volume specific power is increased by 12.5%. At the same time, the power system continues to maintain the technical advantage of fuel economy. On the premise that the curb weight of the whole vehicle is increased by nearly 250 kg, the dynamic performance of the whole vehicle is obviously improved, but the fuel economy is poor.
Maintain the original level 1.2 kg/( 100 km). China's national "863" high-tech project continues to support the research and development of fuel cell vehicles. During the "Twelfth Five-Year Plan" period, in order to maintain the technological commanding heights of electric vehicles in China, we will continue to support fuel cell vehicles. From the industrial point of view, even during the "Tenth Five-Year Plan" global fuel cell vehicle industrialization boom, China automobile industry did not make large-scale investment in fuel cell vehicles. After entering the "Twelfth Five-Year Plan", SAIC made a five-year plan for the development of fuel cell vehicles, and started to invest a lot of money in the research and development of fuel cell vehicles with Xinyuan Power as the supplier of fuel cell stacks. At present, FCV is developing the third generation fuel cell vehicle. In the 20 1 1 bibby derby, the FCV developed by SAIC ranks third in the fuel cell vehicle category.
Tongji University has developed several rounds of fuel cell vehicles, and the developed fuel cell vehicles have been put into large-scale demonstration operation in the Olympic Games and the World Expo. During the Twelfth Five-Year Plan period, Tongji University will integrate fuel cell vehicles for China FAW Group, Dongfeng Motor Company, Chery Automobile Co., Ltd. and China Changan Automobile Group Co., Ltd. The technical parameters of typical fuel cell hybrid vehicles under urban cycle conditions in China are shown in Table 6.