Current Density Distribution in the Lateral Direction of Conventional and Interdigitated Flow Field

In proton exchange membrane fuel cells, diffusion is a primary mechanism to transport gaseous species (oxygen and water vapor) between the flow channel and the catalyst layer in conventional flow field, whereas in an interdigitated flow field convection and diffusion both play vital role. Similarly, in a conventional flow field capillary effect is dominant in removal of liquid water, while in an interdigitated flow field both capillarity and the pressure difference between inlet and outlet channels contribute to the liquid water removal. Many computational studies available in literature have proven that this fundamental difference in transport mechanisms results in the differences in the overall cell performance and in the current density distribution in the land-channel direction between PEMFCs with interdigitated flow field and conventional flow field such as [1-2]. However, to best of our knowledge there is no study present in literature to experimentally show the current distribution in land-channel direction.

Our objective is to measure current density distribution in the land-channel direction and compare current density distribution profile for interdigitated and conventional flow field. A segmented cell is developed to measure current density distribution in the land-channel direction at sub-millimeter resolution of 350 μm. This technique is then applied to study current density distribution in land-channel direction of PEM fuel cell with interdigitated flow field and conventional flow field (see Figure 1a and b).

Figure 1. Current density distribution in the land-channel direction at 0.2 V, 60 ^oC and 90% RH a) conventional b) interdigitated flow field

1. A. Kazim, H.T. Liu, P. Forges. Journal of Applied Electrochemistry, 29, 1409 (1999).
2. L. Chen, H. B. Luan, Y.L. He, W. Q. Tao. International Journal of Thermal Sciences, 51 132 (2012).