The hydrogen energy industry chain includes the manufacturing, storage, transportation and application of hydrogen, and efficient and safe hydrogen energy storage and transportation technology is the prerequisite for the large-scale application of hydrogen energy.
At present, the main technical routes of hydrogen storage are high-pressure hydrogen storage, liquid hydrogen storage, and solid-state hydrogen storage. Compared with liquid hydrogen storage and solid-state hydrogen storage, high-pressure gaseous hydrogen storage has the characteristics of simple equipment structure, low energy consumption, fast hydrogen charging and discharging speed, wide temperature adaptation, and small impact on the working environment.
High-pressure hydrogen storage is the compression of hydrogen into a hydrogen storage container by a compressor at room temperature to increase the density of hydrogen per unit volume. According to different application scenarios, it is divided into stationary hydrogen storage and mobile hydrogen storage, and stationary hydrogen storage is mainly used in hydrogen refueling stations, emergency power supplies, backup power supplies and hydrogen energy storage.
The main hydrogen storage equipment involved in high-pressure gaseous hydrogen storage technology is gas storage cylinders.
There are four main types of high-pressure hydrogen storage cylinders: all-metal cylinders, metal liner fiber circumferential winding cylinders, metal liner fiber full-wound gas cylinders, and non-metallic liner fiber full-wound gas cylinders.
1.The mass volume density is smaller than that of other hydrogen storage methods, and the hydrogen storage efficiency is not high.
2.High-pressure storage, poor safety, easy to produce ** risk.
The atom size of hydrogen is small, it is easy to react with the metal of the hydrogen storage container, and the phenomenon of "hydrogen embrittlement" occurs, and due to high-pressure storage, once hydrogen leakage occurs, it will cause accidents such as **, and the safety requirements in the storage and transportation process are higher.
In order to solve the problem of "hydrogen embrittlement" of hydrogen storage cylinders and related components, the concept of "V-shaped hydrogen storage bottles" has been proposed in the market. The V-type hydrogen storage bottle is still wound with carbon fiber composite materials, without using any inner tank, and the working pressure can reach 70 100MPa, which has the advantages of no hydrogen embrittlement, no corrosion, and a service life of more than 30 years, and can also be used in aerospace and vehicle fields. However, this kind of hydrogen storage bottle is still in the research and development stage, and there is no clear direction in the technical route and container material.
3.High requirements for the material and process of hydrogen storage bottles.
Among the four hydrogen storage bottles currently used in the market, the weight-to-volume ratio of type and type is large, and it is mainly used in hydrogen storage scenarios of hydrogen refueling stations and hydrogen transportation by long-tube transport trailers.
Due to the use of fiber full winding structure, the type bottle has the advantages of small weight-to-volume ratio, high hydrogen storage density per unit mass, and small mass volume of hydrogen storage bottle, and is mainly used in hydrogen fuel cell vehicles.
However, the molding process of the IV bottle liner is mainly injection molding, blow molding and rotational molding. Although the cost is low and widely used, the yield rate is also low, and it must be cooperated with the subsequent welding process.
4.It is difficult to increase storage density.
In order to improve the volumetric energy density of hydrogen, improve the efficiency of storage and transportation, and reduce the cost of storage and transportation, hydrogen storage is usually carried out by cooling and pressurization.
At present, domestic hydrogen refueling stations mainly use a pressure of 35MPa for storage and transportation, and in order to adapt to the pressure of the hydrogen supply system of fuel cell vehicles, it needs to be developed to 70MPa.
According to public information on the Internet, hydrogen energy vehicles store 5 kg of hydrogen, and at a pressure of 70MPa, the capacity of the storage system is about 200 liters, which is 3-4 times the capacity of gasoline tanks in today's fuel vehicles.
This difficulty has severely limited the development of on-board hydrogen storage cylinders. At the same time, the pressure above 70MPa has a marginal decreasing trend for the increase of density, and the cost increases significantly.
Equal energy (1.)4GJ), the comparison of gasoline and various types of hydrogen storage technologies in terms of volume and mass (including containers).
Data**: Hydrogen storage and transportation
In terms of technology, with the continuous breakthrough of industrialization technology, hydrogen storage bottle technology is developing in the direction of lightweight, high pressure, high hydrogen storage density and long life.
In terms of industry standards, the following standards related to high-pressure gaseous hydrogen storage have been published:
Some experts said that high-pressure gaseous hydrogen storage, as the most basic storage and transportation method, has more mature technology, more flexible operation, and lower short-distance transportation costs, so it will still occupy a dominant position in hydrogen energy storage technology for a long time in the future.
Author: An Yi).