Spanish scientists have developed a proton exchange membrane fuel cell with a bipolar plate based on a nature-inspired structure. This architecture, according to its creators, exhibits remarkable performance when operating at high relative humidity values of 90%.
Researchers at the University of Seville in Spain have developed a proton exchange membrane fuel cell (PEMFC) with a bipolar plate (BP) based on a nature-inspired structure. According to the scientists, BPs are crucial for optimal water management in the cell, which prevents flooding and improves cell operation at high current densities. “A properly optimized flow design allows the fuel cell to develop a uniform and stable power output and to properly handle reaction-derived water,” they said.
Using computational fluid dynamics (CFD) models and simulations, the Spanish group studied several bio-inspired flow channel structures such as leaves, lungs or sponges and sought to assess which of them they offer the best performance in terms of reagent delivery, pressure and velocity fields. .
The academics created three different stream channel architectures. The first, named Design A, is symmetrical with respect to the BP diagonal and consists of a branch running along the BP diagonal with branching secondary branches in a perpendicular direction, themselves connected by tertiary perpendicular branches. The second flow channel configuration, called design B, consists of a double serpentine flow channel with continuous flow from inlet to outlet and geometric symmetry with respect to the main diagonal BP. The Design C architecture is based on an input manifold and an output manifold connected in parallel with six groups of straight channels in sets of seven channels each.
The performance of the three architectures was compared to that of a reference design with a 50 cm parallel-coil design2 active area of the American company ElectroChem Inc. “Experimental work was carried out with a PEM fuel cell test station, dedicated to experimental testing of PEM single cells and short stacks up to 500 W”, the researchers said .
A slightly modified version of Design C including porous graphene sponge inserts was the architecture with the best performance. It exhibited the most homogeneous velocity flow field, an average velocity of 1.71 m/s), a standard deviation velocity of 2.87 m/s, and a lower pressure drop of 1042.8 Pa.
“Even though lower performance was observed for the biomimetic design compared to parallel serpentine for lower cell temperatures (4.1% lower), higher cell backpressure (6.2% lower), and stoichiometric factor higher cathode of 3.5 (21.2% lower), the new biomimetic design showed better performance when operated at higher relative humidity values of 90%, reaching a higher peak power of 6, 0%, indicating that the new proposed biomimetic design is particularly suitable for better water management at high reagent humidity,” the academics concluded.
Their findings were presented in the article Experimental and numerical investigation on the design of a bioinspired PEM fuel cell, published in Energy.
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