Time:2024.12.24Browse:0
From an international perspective, fuel cells have now entered the market introduction stage, and the power of the engine has been greatly improved. It can run more than 500 kilometers with a 70MPa hydrogen bottle. The power generation principle of fuel cells is electrochemistry, so it is more efficient; it works as an internal combustion engine, and the fuel is stored in a storage tank, so it is safer than lithium-ion batteries. Compared with electric vehicles and plug-in hybrid vehicles, fuel cell vehicles are more suitable for high-power, long-distance transportation, so they have obvious advantages in applications in buses and heavy-duty vehicles. At present, hydrogen fuel cells have basically met the requirements for vehicle use in terms of lifespan, reliability, and applicability, and the country has also mastered the core technology of hydrogen fuel cells. At present, there are about 10 domestic hydrogenation stations in operation, and it is expected that there will be about 100 next year. The most frequently operated ones are Zhangjiakou, Yunfu and Shanghai, with the largest amount of hydrogenation. China has mastered the core technology of fuel cells and has accumulated rich experience through a large number of demonstration operations, and has the conditions for large-scale demonstration operations. But the current problem is that fuel cells still do not have large-volume production lines, the cost is high, and they are restricted by hydrogen refueling stations. Therefore, from the perspective of stacks and fuel cells, the current top priority is to reduce the amount of platinum used and the cost of catalysts. If China's automotive fuel cells want to be competitive internationally, the core issue is to increase the operating current density and specific power of the stack. From an international perspective, fuel cell vehicles have reached the volume level of a four-cylinder internal combustion engine. Honda announced that it has reached the level of a six-cylinder internal combustion engine, with a power density exceeding 3 kilowatts per liter. Our domestic installed battery stacks are currently about 2.0 kilowatts per liter, so the specific power of our battery stacks is about 1/3 lower than that of foreign countries. At present, we must first achieve mass production of key materials, electrocatalysts, proton exchange membranes, three-in-one membrane electrodes, and bipolar plates as soon as possible to lay the foundation for reducing stack costs and improving stack consistency. Secondly, we need to reduce the amount of platinum used and further improve the reliability and durability of the stack and battery system. In order to reduce the cost of fuel cell engines, especially the cost of stacks, we must first study how to increase the specific power of single cells and reduce chemical polarization, ohmic polarization and mass transfer polarization. In order to reduce chemical polarization, it is necessary to develop more efficient electrocatalysts.
Now, single-cell research in domestic laboratories has reached above 0.7V at 1 amp per square centimeter, and above 0.6V at 2 amps per square centimeter. We are moving towards 2.5 amps. In the future, it will be developed to 2 to 2.5 amps per square centimeter, so that our battery stack level can reach Toyota's level or even exceed Toyota's level. From the perspective of the stack, the greater the flow field resistance, the better the consistency of the stack, but as the air supply pressure increases, the internal consumption of the air compressor will also increase. For this reason, we need to study air compressors with low internal consumption to ensure the high power density output of the stack. In addition, the consistency of bipolar plate preparation must be improved, especially the flatness. Whether it is a metal plate or a graphite plate, flatness determines the consistency of the stack and is a key factor. The stacks are assembled according to the press method, and their main components are bipolar plates, MEA, and seals. Therefore, it is necessary to further improve the assembly process of the stack and develop strict positioning technology. The life of the fuel cell is the result of the cooperation between the stack and the system, not the efforts of the stack itself. Therefore, we must also strengthen the research and development of key components of the stack and system parts. First, improve the fuel cell industry chain as soon as possible and establish production lines for key materials such as diffusion layer carbon paper. In addition, attention should not only be focused on membrane electrodes and bipolar plates, but also on the development of air compressors and hydrogen circulation pumps. Second, it is necessary to increase the working current density of the stack, increase the volume and weight specific power of the stack, reduce the cost of the stack, and lay the foundation for the development of passenger cars. Third, it is necessary to conduct in-depth research on the attenuation mechanism of the stack, develop corrosion-resistant and stable new materials, and greatly improve the reliability and durability of the engine. Reliability and durability are determined by both the system and the stack. As the stack improves, the system can be simplified. Therefore, the stack and the system must cooperate with each other to simplify the battery system through the advancement of key materials. Fourth, it is necessary to carry out theoretical and applied research on ultra-low platinum and non-platinum electrocatalysts to further reduce the platinum usage in batteries to less than 0.1 grams per kilowatt, which is a basic requirement for the commercialization of automotive fuel cell engines internationally. Fifth, establish testing and durability rapid evaluation methods for key components, stacks and battery systems. This is also something the Fuel Cell Standardization Committee is doing. Therefore, we must establish a neutral testing agency as soon as possible, which will play a significant role in promoting the progress of my country's fuel cell technology and catching up with the world level. It is hoped that fuel cell vehicles will reach the rising stage of the S-shaped curve of commercialization as soon as possible. After reaching a certain level, they can make profits without subsidies. Some people predict that in terms of key materials, as long as the amount of platinum used in fuel cell vehicles is reduced, the cost will be lower than that of lithium batteries, but this requires the joint efforts of our technicians.
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