Effect of humidification and cell heating on the operational stability of polymer electrolyte membrane fuel cell

Effect of humidification and cell heating on the operational stability of polymer electrolyte membrane fuel cell

The commercialization of the PEM fuel cell is hindered by a few factors, which include the storage of hydrogen, water and thermal management, catalyst poisoning, corrosion in copper current collectors among the factors, water management issue mainly arises due to the water generation (i.e., flooding) due to the electrochemical reactions, which leads to the slowing down of the electrochemical reaction rate, resulting in a decline in production effectively.  Hence the water management issue of the PEM fuel cell should also be studied in detail, and solutions should be found for better commercialization of the PEM fuel cell technology, Methods like purging of water accumulated in the anode side during the operation of the PEM fuel cell can assist in water management and maintaining the steady operation of the cell numerous other factors, including operating temperature, pressure, and gas stream humidification, are known to have significant impact on the PEM fuel cell performance. Understanding the impact of these factors on fuel cell operations is crucial for enhancing the PEM fuel cell performance. The cell operating temperature dramatically impacts the electrical and thermal efficiency as well as the performance of the PEM fuel cell, experimentally illustrated how the operating cell temperature affected the polarization curve when the inlet gas reactants were heated to 75°C, 80°C, 85°C, and 90°C. It was found that for moderate to high current densities, the fuel cell performance considerably increased with a rise in cell temperature.

They found that the droplet cycle time drastically decreased from 14 s to 0.5 s when the cell temperature increased from 25°C to 75°C.  And found that raising the operating temperature from 120°C to 200°C improved the fuel cell efficiency; nevertheless, the optimal operating temperature was claimed to be in the range of 160°C -180°C in order to obtain a high-power density and lower maintenance costs.

It is well known that the performance of the PEM fuel cell will be significantly influenced by the humidification on the cathode and anode sides because it controls the water balance within the cell. To improve the water balance within the cell, the water generated within the cell during its operation was utilized for reactant hydration, and it is considered as self-humidification. Self-humidification reduces the necessity of providing an external humidification system. Thus, the weight as well as the cost of the PEM fuel cell systems, can be reduced to a great extent. Many research work has been focused on the experiments and developed models to understand the effect of self-humidification on the performance of the PEM fuel cell. Examined the distribution of water in the cell under dry gas operation by measuring the quantity of water on the anode and cathode sides and confirmed that under a variety of operating conditions, the back-diffusion of water to the anode was the primary mechanism for managing water in the self-humidified PEM fuel cell.