It is understood that at present, hydrogen fuel cell vehicles in China are mainly using gaseous hydrogen, and hydrogen fuel cell vehicles using liquid hydrogen have not been mass produced. However, this situation may be broken in the future. It is reported that a Shanghai energy company is planning Research and manufacture of hydrogen fuel cell vehicles and hydrogen refueling stations using liquid hydrogen as fuel.
Why does hydrogen fuel cell vehicles currently not use liquid hydrogen? What are the advantages and difficulties of liquid hydrogen fueled hydrogen fuel cell vehicles? What is the future of this technology in the future?
Difficulties in the technical shortage of equipment, domestic manufacturers difficult to try
It is understood that the hydrogen fuel cell vehicles currently available in China are basically based on gaseous hydrogen fuels, such as the fuel cell battery bus of the Yangtze River Auto, Foshan Feichi Automotive Hydrogen Fuel Cell Bus, etc. Zhang Ruiming, General Manager of Guangdong Tairos Automobile Power System Co., Ltd. said The technology of MH-fuel-cell vehicles is relatively mature and can enter the commercial stage. However, the technology of liquid-hydrogen-fuel-cell vehicles is not mature enough and the cost is high. Therefore, hydrogen fuel-cell vehicle manufacturers do not use liquid hydrogen as fuel.
Zhang Ruiming said that if liquid hydrogen is to be used as a fuel to drive fuel cell vehicles, it is necessary to first liquefy gaseous hydrogen into a liquid state. This requires a low temperature of -253°C and a relatively high pressure environment, and requires excellent performance after being manufactured. Insulation, pressure-resistant containers are used for storage, otherwise evaporation is very large and it is difficult to use for automotive power systems.
On the one hand, the technical requirements are very high. On the other hand, the cost of these materials and equipment is quite high. The car prices that are made out are probably not acceptable to customers in the automotive market. So Zhang Ruiming says frankly that liquid hydrogen fuel is used for shuttle-level traffic. Tools, used in general cars are still relatively rare.
In hydrogen refueling stations, it is not easy to use liquid hydrogen to refuel cars. Tian Lili, assistant to general manager of Shanghai Hydro-Fengfeng Energy Technology Co., Ltd., said that the current hydrogen refueling stations are mainly filled with compressed hydrogen and no liquid hydrogen is used. The reason is that in addition to technical difficulties and expensive equipment, there is a lack of relevant technical standards and policy specifications. Tian Lili believes that they will not be involved in this field until a detailed liquid hydrogen hydrogen station specification is introduced in the country.
New technologies and new advantages, companies want to break the gap
However, liquid hydrogen is a blank field that has been taken seriously by domestic companies and tackles key issues. Recently, a company called Shanghai Sheng Industrial Co., Ltd. is making related industrial planning. Mr. Cheng, the relevant person in charge of the company, told reporters that they New technologies will be used to co-produce hydrogen fuel cell trucks powered by liquid hydrogen, and plans to establish a liquid hydrogen refueling station.
Regarding why hydrogen fuel cell vehicles using liquid hydrogen fuel are used, Mr. Cheng said there are two main reasons:
1. In the use of compressed hydrogen, there are significant shortcomings in China. For example, if the price of carbon fiber materials for manufacturing high-pressure hydrogen cylinders is relatively high, Chinese enterprises lack the market pricing power; in terms of high-pressure compressors, Chinese enterprises have not yet reached the Japanese and South Korean enterprises. The level of technology, the purchase price is not cheap; Chinese companies have been using 35 MPa hydrogen bottle, the relevant standards have been modified in the past two years, but the manufacturers of manufacturing process improvements still need time to adapt.
Second, liquid hydrogen transport is more convenient to build stations and cheaper. The traditional way of transporting hydrogen gas is to use a tow truck to transport hydrogen. The amount of hydrogen transported by a liquid hydrogen transport vehicle is equivalent to 8 to 10 such tow transports. The cost advantages of long-distance transportation can be easily demonstrated. In addition, the construction of a liquid hydrogen refueling station can save investment costs of 15% to 20% compared to the construction of compressed hydrogen stations.
Third, liquid hydrogen is relatively safer. If compressed hydrogen leaks, the compressed gas needs to find space quickly to release the pressure; liquid hydrogen is normal pressure, even if the liquid hydrogen bottle leaks, liquid hydrogen flows to the ground and it quickly takes within one to three minutes. Gasification requires gasification to absorb heat, rapidly condense the water vapor in the air, form clouds, block hydrogen, and prevent it from escaping with the oxygen in the air to generate explosive gases, thus being safer than compressed hydrogen. (Editor's note: These characteristics have not yet been confirmed by the authority. Some experts pointed out that the liquid hydrogen storage conditions are harsh, but the technology is not up to standard but it easily leaks, and the rapid expansion after the leak, more likely to cause an explosion. The use of hydrogen safety depends on many conditions, it is difficult to 'More secure'
With regard to technical doubts about the storage and use of liquid hydrogen, which is widely questioned by the public, Mr. Zheng said that they already have mature insulation technology to keep the daily evaporation of liquid hydrogen between 1/1000 and 2/1000. The developed liquid hydrogen storage tank can be placed in trucks and allow trucks to travel for 1,700 kilometers.
However, for how to achieve the above target data, specific equipment performance and product appearance, Mr. Zheng does not make public announcement on the ground of trade secrets.
In addition, the company’s team also plans to build a liquid hydrogen fuel cell truck transportation line between Beijing and Shanghai, Shenzhen and Wuhan, and between Wuhan and Chengdu in the future. The three lines will build four to six liquid hydrogen and 35 megabits along the way. Pa, 70 MPa compressed hydrogen interlinked refueling station.
There are new directions, the direction of the industry can be concerned
For this news, relevant experts said that liquid hydrogen as a technical direction and business model is worthy of attention and understanding by companies in the industry, but there is no corresponding physical presence in the country, then it can not be considered as a real commercial product.
As a matter of fact, as early as 2016, Deputy General Manager of Beijing PeriHua Hydrogen Energy Technology Co., Ltd. He Wenzhi had publicly stated that China is storing hydrogen in a gaseous state, but in the future, liquid hydrogen will be a development direction. Because Europe and the United States, Japan Liquid hydrogen is used in many places. Hydrogen is transported in liquid form.
Technical Director of Beijing Zhongke Fuhai Cryogenics Technology Co., Ltd. Xiong Lianyou was also present at the first China (Foshan) International Conference on Hydrogen and Fuel Cell Technology and Product Promotion. There are nearly 400 hydrogen refueling stations in the world, including 1/3 of them. It is a liquid hydrogen refueling station. Compared with the hydrogen hydrogen refueling station, the liquid hydrogen refueling station has the characteristics of high density of liquid hydrogen storage, low storage and transportation costs, low storage pressure, and safety. Xiong Lianyou believes that liquid hydrogen is transported and stored in The future of the hydrogen energy industry chain will become more and more important. It is an inevitable means for the large-scale application of FCEV (fuel cell electric vehicle).