NIE 2023 | Heidever Gu Ronglei: Efficient Turbo Machinery for Hydrogen Fuel Cell Vehicles

Dr. Gu Ronglei introduced that against the backdrop of global consensus on carbon reduction, major countries around the world, especially the United States, Japan, South Korea, and Europe, have set clear hydrogen energy development goals. For China, the strategic purpose of using hydrogen energy to improve the energy structure is to enhance energy security.

Currently, hydrogen fuel cell vehicles are in their infancy with a low number of ownerships. Last year, the number of hydrogen fuel cell vehicles in China just exceeded 10,000 units. The current target is to reach 50,000 units by 2025 and 1 million units by 2030.According to the current development trend of hydrogen fuel cell vehicles, the target for vehicle ownership by 2025 is very likely to be achieved.To promote the development of hydrogen fuel cell vehicles, demonstration urban clusters have been established in various places, along with a series of supportive policies.

Dr. Gu Ronglei stated that the basic architecture of hydrogen fuel cell vehicles is consistent with current electric vehicles, with the core focusing on three major aspects: batteries, motors, and electronic control systems. At the technical level, different components are added to electric vehicles to form different powertrains. For example, after adding a fuel cell stack and a high-pressure hydrogen cylinder to an electric vehicle, it becomes a hydrogen fuel cell vehicle. If an electric vehicle uses external charging while adding the original engine and switches between different operating conditions, it becomes an electric plug-in hybrid vehicle.

The biggest change in hydrogen fuel cell vehicles is the significant proportion they now account for in heavy-duty trucks. The initial application of hydrogen fuel cell vehicles from 2018 to 2019 was focused on demonstration applications for urban buses and logistics vehicles. In recent years, with the actual promotion and development, as well as continuous improvement in technical levels, the advantages of hydrogen fuel cell vehicles with high power density have gradually become apparent in application scenarios such as long-distance, heavy-duty logistics trucks or mining trucks with large load capacity and long cruising ranges. According to the technical roadmap formulated by the Ministry of Industry and Information Technology, commercial vehicle hydrogen fuel cell vehicles will possess greater power, higher efficiency, longer lifespan, and lower costs in the future.

In addition, Dr. Gu Ronglei briefly introduced the sub-components of hydrogen fuel cell systems. Apart from the stack, the hydrogen fuel cell system has a hydrogen supply system that provides hydrogen gas, mainly including hydrogen circulation pumps and control valves to achieve precise control of hydrogen usage. The supply of oxygen requires compressed air to be input into the stack for an electrochemical reaction with hydrogen. During this reaction process, a large amount of heat is generated, so the thermal management system is also crucial. The control system is used to control the usage of hydrogen and oxygen to ensure effective reactions, the service life, and reliability of the battery system. The function of the air filter is to ensure the purity and cleanliness of air before it enters the stack. The air compressor increases the air density to ensure that oxygen and hydrogen react fully.

Dr. Gu Ronglei first introduced the contradiction between fuel cell system efficiency and air compressor power consumption. As the power of the fuel cell system increases, the air flow rate required by the compressor becomes higher, and the compressor itself consumes more power. Therefore, most of the energy generated by the stack is consumed by the compressor, thereby reducing the efficiency of the fuel cell system.

In fuel cell vehicles, since a significant portion of the energy at the stack outlet exists in the form of pressure or temperature, this energy can be recovered through turboexpansion engines to compress and transport air, thereby reducing the demand for motor drive and improving the efficiency of the entire fuel cell system. According to tests conducted by Hydrotech at the customer end, this method can increase the power of the air compressor by at least 30%, allowing more power to be used to drive the wheels, thereby enhancing the value of fuel cell vehicles. Dr. Gu Ronglei stated thatFor a 49-ton heavy truck, with several years of driving mileage, the use of efficient turbo machinery can help reduce operating costs by more than 300,000 yuan.

In addition, Heidenhain has also applied other advanced technologies to improve efficiency. For example, air-supported bearings replace traditional oil-lubricated bearings. Relying on the high-speed rotation of the rotor, a compressed air film is formed between the rotating shaft and the bearing foil for support, achieving zero friction loss and further enhancing operational efficiency. Since last year, Heidenhain has been collaborating with major domestic system manufacturers and will conduct multiple tests this year at the earliest and achieve final applications in the future.

Finally, Dr. Gu Ronglei summarized that carbon neutrality has become a global goal, and hydrogen fuel cell vehicles will enter a period of rapid development from 2025 to 2026. With the application of high-power engines, efficient turbo machinery will become the main technical route to improve overall system efficiency.