The "Blowout" of Cathode-Closed Air-Cooled Stacks is Coming With the gradual expansion of low-power application scenarios such as tourist buses, forklifts, unmanned aerial vehicles (UAVs), and two-wheeled vehicles, air-cooled stacks have slowly entered the vision of mainstream fuel cell applications. Cathode-closed air-cooled stacks, with their advantages of good environmental adaptability, durability, and simple maintenance, have attracted much attention in the air-cooled fuel cell technology route and become a hot spot of pursuit.
Technical Characteristics and Application Status of Cathode-Closed Air-Cooled Stacks
Air-cooled stacks can be divided into two categories according to their structural characteristics: cathode-open and cathode-closed. Among them, the open cathode air-cooled stack: the cathode is directly exposed to the environment, and ambient air is introduced into the stack through devices such as fans. The air serves both as a source of reaction gas and as a heat dissipation medium.
The cathode-closed air-cooled stack is characterized by the fact that the cathode is not in direct contact with the environment, and air supply and heat dissipation are carried out separately. A dedicated air supply system, such as a blower or air compressor, is usually required to provide the oxygen needed for the reaction, and an independent heat dissipation system is used to remove the heat generated during the operation of the stack.
Compared with open cathode air-cooled stacks, cathode-closed air-cooled stacks are less affected by environmental factors (such as temperature, humidity, and air quality) due to the independent air supply and heat dissipation. Moreover, they can to a certain extent avoid the adverse impact of polluted air on the service life of fuel cells, resulting in better durability and longer service life.
"The performance of cathode-closed air-cooled stacks largely depends on the design of gas channels and manifolds to uniformly distribute the supplied air," said a technical director of a domestic stack enterprise. Cathode-closed air-cooled stacks require complex air supply subsystems, which may include compressors, humidifiers, air filters, etc. This also makes them relatively less affected by surrounding environmental conditions, especially temperature and humidity.
Of course, the advantages of cathode-closed air-cooled stacks are based on their relatively complex structure, which also leads to their relatively higher cost compared with open cathode air-cooled stacks. As Gaogong Hydrogen Power learned in the survey, as of June 2025, under the premise of bulk procurement, the price of open cathode air-cooled fuel cells is generally more than 4,000 RMB/kW, and the price of cathode-closed air-cooled systems is at least 30% higher than the former.
At this stage, cathode-closed air-cooled stacks are suitable for high-power density applications (greater than 1A/cm²). The application scenarios require sufficient space for fuel cell auxiliary systems (cooling, air supply, and pretreatment subsystems), with a typical power range between 2 kW and 100 kW.
Overall, at this stage, as the fuel cell industry gradually expands from high-power water-cooled stack systems used in commercial vehicles and passenger cars to small and medium-power air-cooled stack systems such as UAVs, forklifts, and two-wheeled vehicles, the market expansion of closed air-cooled fuel cells has just begun. Whether it can seize more market share with its own advantages remains to be seen. From the perspective of future technological development trends, future research on closed air-cooled stacks needs to focus on minimizing support systems to reduce the complexity, parasitic load, and floor space of the overall system, as well as conducting system management and control to achieve optimal performance.
