Comparative study on bipolar plate geometry designs on the performance of proton exchange membrane fuel cells

Bipolar plates are designed to provide structural rigidity to Proton Exchange Membrane Fuel Cell (PEMFC) and contribute 80 % of the total weight of the cell. Over 40 % of the total cost of the cell originates from the type of bipolar plate used in the development of the cell. The present study draws inspiration from existing conventional serpentine and parallel channel designs in developing novel tapered dual serpentine channel (TDSC), tapered parallel channel design (TPCD) and the tapered dual maze channel (TDMC) in ANSYS Fluent. The results highlighted the fact that tapered inlet and outlet channel geometry designs had significant impact on the overall cell performance. That is, pressure build up within the cell, the velocity of the reacting species and even their distribution are largely influenced by the flow plate geometry design. There was 2.163 % increase in the current flux density magnitude for the TDMC fuel cell compared to the TDSC and 1.421 % increase in current flux density magnitude compared to the TPCD. 0.52 W/cm2 was recorded as power density for TDMC, 0.44 W/cm2 for the TPCD and 0.38 W/cm2 TDCS. The TDMC further showed 13.67 % increase in current density compared to the TPCD and 22.78 % increase in current density compared to the TDSC. These results corroborate with Bernoulli's principle, that an increase in the velocity of a fluid results in a decrease in static pressure which in the case of Proton Exchange Membrane Fuel Cells (PEMFC) lead to higher rate of reaction and easy dissipation of the product water. This phenomenon buttresses the justification for the increase in cell performance due to thermal and water management improvement. The outcome of the investigation also showed that the pressure drop in the channel geometry was lower in the case of the TDMC compared to the other types (TPCD and TDSC). Due to the improved pumping power of the cell, uniform temperature distribution and pressure, the maze channel geometry design showed better prospects for their application in the automotive industry. This study will, however, serve as a reference point in designing and developing flow plate for a proton exchange membrane fuel cell to accelerate its commercialisation.