Numerical and Experimental Verification of the Polymer Electrolyte Fuel Cell Performances Enhanced by Under‐Rib Convection

Abstract

Understanding the current density distributions in polymer electrolyte fuel cells (PEFCs) is crucial for designing cell components, such as the flow field of bipolar plates. A new serpentine flow field equipped with sub‐channels and by‐passes (SFFSB) was numerically and experimentally confirmed to enhance the reactant transport rates and liquid removal efficiency compared with a conventional advanced serpentine flow field (CASFF). Consequently, the maximum current and the power densities of the SFFSB were increased due to the promotion of under‐rib convection. In this study, current density distributions are measured under transient conditions to verify the PEFC performances enhanced by under‐rib convection. The current density distributions of the SFFSB are compared with those of the CASFF. The results show that the SFFSB has a higher local current density and a more uniform distribution than the CASFF, therefore, the PEFC performances with the new flow field of SFFSB is enhanced by the better current density distributions.

Comparison of Numerical and Experimental Studies for Flow-Field Optimization Based on Under-Rib Convection in Polymer Electrolyte Membrane Fuel Cells

“…The fuel cell operation is characterized as gas transport and transformation of one species to another [25]. The geometric details and other physical parameters of the cell components used in this research can be found in our previous papers [1,[26][27][28] and are summarized in Tables 1-3. Table 2.…”

“…Table 2. Geometric details of the cell components used in this simulation [1,[26][27][28]. GDL: gas diffusion layer.…”

“…Generally, since much of the water formed at the GDL and rib area is absorbed into the membrane by under-rib convection, then the water content under the rib is higher than that under the adjacent channel. Under-rib convection is the same process as cross-leakage flow [28]. On the membrane's cathode side, the water content increases from the inlet toward the outlet because the decrease of total pressure affects the water discharge conducted by the air flow.…”

Efficient fuel utilization by enhancing the under-rib mass transport using new serpentine flow field designs of direct methanol fuel cells

“…One direction is to develop the under-rib mass transport. The roles of the under-rib mass transport were previously studied [2,[12][13][14][15][16][17][18][19][20][21][22]. It was reported that for a specified mass flow rate, the under rib convection is mainly affected by different factors such as the rib width, the pressure difference between the adjacent channels, and the diffusion layer permeability [9,23].…”

“…Several researchers investigated the serpentine flow field with adding sub-channel and bypasses between the conventional channels to control the under-rib convection. They concluded that these additions enhance the reactant transport, enable more effective utilization of the electrocatalysts, and improve the reaction products removal [12,13,18,22].…”