Numerical-Based Thermal Analysis of Proton Exchange Membrane Fuel Cells

Abstract

With the urgent global concerns of climate change, governments, industry and researchers all now place a top priority on the shift to more sustainable energy technology. Fuel cells have emerged as an alternative to conventional sources of power, due to their ability to generate electricity with high efficiency and low emissions. Fuel cells are electrochemical devices that directly convert the chemical energy from fuels like hydrogen into electrical energy with high conversion efficiencies. Among various fuel cells, proton exchange membrane fuel cells (PEMFCs) have gained popularity and one of the important aspects of PEMFC is to maintain ideal operating conditions, particularly temperature for its effective operation. A numerical simulation has been conducted to analyze the temperature distribution within rectangular cooling plates with active area of 4437mm2. The performance of channels with varying width of channels, rib and header is evaluated in terms of temperature uniformity index, temperature difference and pressure drop for 15 different cases. The results show that the geometrical variations of the cooling plate play a crucial role in maintaining a uniform temperature. It was observed that the temperature uniformity index and the temperature difference decreased by approximately 30% for a higher channel-to-rib (CR) ratio compared to the base case with a smaller CR ratio. Additionally, the pressure drop for a higher CR ratio was lower than that of the other cases. To further improve the temperature distribution, design modifications were made by introducing pins at various locations in the header's inlet and outlet for 9 different cases. Although the impact of the pins was minimal due to the relatively small header size, the maximum temperature recorded was still lower than that of the baseline cases. Consequently, improved cooling performance can be effectively achieved by varying the channel geometry across the plate in parallel straight channels and through further design adjustments, such as strategically incorporating pins.