The development trend of hydrogen energy

1. Fuel cells

1.1 Fuel cell technology

Fuel cell is an important way to utilize hydrogen energy efficiently. The principle of hydrogen fuel cell is to convert chemical energy into electricity and heat energy when hydrogen and oxygen are combined to generate water. The process is not limited by the Carnot cycle effect, and the theoretical efficiency can reach more than 90%, which has a high economy. There is a tough diaphragm between the anode and cathode of the fuel cell to isolate hydrogen and oxygen, which effectively avoids the danger of combustion and explosion caused by direct contact between hydrogen and oxygen. Hydrogen enters the anode of the fuel cell and is broken down into hydrogen ions and electrons by the action of a catalyst. Then, hydrogen ions pass through the diaphragm to the cathode, where they combine with oxygen to form water under the action of a catalyst, and electrons move through an external circuit to the cathode to form an electric current.

At present, fuel cell technology mainly includes alkaline fuel cell, phosphate fuel cell, solid oxide fuel cell, molten carbonate fuel cell and proton exchange membrane fuel cell. From the commercial application point of view, molten carbonate fuel cells, proton exchange membrane fuel cells and solid oxide fuel cells are the most important three technical routes. Among them, proton exchange membrane fuel cell due to its low operating temperature, fast start-up, high specific power advantages, very suitable for application in the field of transportation and fixed power supply, and gradually become the mainstream application technology at home and abroad at present. Solid oxide fuel cell has the advantages of wide fuel adaptability, high energy conversion efficiency, all-solid state, modular assembly, zero pollution, etc., and is commonly used as a fixed power station in the field of large-scale centralized power supply, medium-sized power distribution and small household cogeneration. China mainly focuses on research and development and industrialization in the field of proton exchange membrane fuel cells and solid oxide fuel cells.

Since the launch of the "Tenth Five-Year Plan" major science and technology special project for new energy vehicles, with the support of a series of major national projects, fuel cell technology has made certain progress, and has initially mastered core technologies such as fuel cell stacks and key materials, power systems and core components, and vehicle integration; The level of some key technology laboratories is close to the international advanced level, but the level of engineering and industrialization lags behind, and the overall technical level lags behind Japan, South Korea and other countries. Specifically, with the gradual promotion of terminal applications of proton exchange membrane fuel cells, membrane electrodes, bipolar plates, proton exchange membranes, etc., have the ability to be localized, but the production scale is small; The development of the reactor industry is good, but the development of the key components industry of the auxiliary system is relatively backward; The system and vehicle industry has developed well, with more supporting manufacturers and larger production scale, but most of them use imported parts from abroad, and the degree of external dependence is high.

1.2 Fuel cell applications

With the continuous maturity of fuel cell technology, related products have gradually entered the stage of commercial application, and are gradually applied to automobiles, ships, rail transit, etc., in the field of transportation, which can reduce the dependence on foreign energy and the emission of fossil energy pollutants and carbon. Fuel cell commercial vehicles take the lead in commercial application, the future lithium battery and fuel cell will become complementary relationship, Academician Ouyang Ming Gao has proposed that "lithium ion battery is more suitable for replacing gasoline engine, hydrogen fuel cell system is more suitable for replacing diesel engine". Compared with pure electric vehicles and gasoline vehicles, hydrogen fuel cell vehicles are not dominant in acquisition costs and use costs, and the future with the increase in application, vehicle costs and hydrogen costs are expected to decrease significantly, and domestic technology still has a lot of room for improvement.

Five. Future development trend

Low-carbon and clean hydrogen has become an important starting point for achieving carbon neutrality.

The national hydrogen production technology route focuses on project demonstration and industrial layout around renewable energy electrolytic water hydrogen production technology and fossil energy hydrogen production +CCUS (carbon capture, utilization and storage) technology. In addition, for fuel cell vehicle terminal application scenarios, hydrogen purification and hydrogen quality research work are carried out to ensure high-quality hydrogen supply. There is a large gap between China's CCUS technology integration, submarine storage and industrial application and the international advanced level, and the number and overall scale of CCUS large-scale demonstration projects are far lower than that of developed countries.