Effect of Bipolar Plate Cooling on Fuel Cell Heat Generation

Heat generation inside the fuel cell is dependent on current densities at the fuel cell’s electrolyte membrane. When the moisture levels are too high, there is a flooding of the electrolyte membrane which prevents the hydrogen and oxygen gases from reaching the membrane. Whereas if the moisture levels are too low then an increase in ohmic loses across the membrane results in decreased energy production. A numerical study was performed to understand how the fluid velocity and thermal conductivity of the bipolar plates affects energy production inside the fuel cell. This was accomplished by using two models, one for the fuel cell and the other for the bipolar plate. The fuel cell model included both the conductive and convective heat transfer as well as the electrochemical heat generation. This model included calculations for determining moisture content which was included in the electrochemical reaction. After setting the model’s geometric configuration and fuel flow rates, this model required the temperature of the bipolar plate model as its input. The bipolar plate mode included the conductive and convective heat transfer with a fluid flowing through a set micro channel configuration. After setting its geometric configuration and flow rates, its input was the heat flux from the fuel cell model. An iterative approach was used to reach steady state convergence between the two models. The effect of varying the flow rates through the bipolar plate on power production was studied. These studies show how low flow rates inhibit power production.