Three‐dimensional simulations for counter‐flow proton exchange membrane fuel cells with thin catalyst‐coated membrane cooled by liquid water

Abstract

Three-dimensional simulations were performed for proton exchange membrane fuel cell (PEMFC) with thin catalyst-coated membrane (CCM) regarding liquid water cooling design. The studied PEMFC follows a counter-flow pattern for the H2 and air stream, which is commonly adopted in today's automotive PEMFCs. For the thermal modeling of the liquid water, conjugate heat transfer model is used. The cooling flow inlet temperature between 60 and 75°C, direction, flow rate between 0.08 and 0.32 L s−1 m−2 as well as the cooling channel number are investigated, specifically. It is found that the cooling inlet temperature directly determines the working temperature of PEMFC under the same cooling flow rate. It means that increasing the cooling inlet temperature can lift the PEMFC operating temperature. The co-direction for the liquid flow and the air stream is found to be better for PEMFC as it can suppress the liquid water formed near cathode outlet. It is then pointed out that the cooling flow rate would determine the along-channel temperature non-uniformity in PEMFC and moderate flow rate is preferred. Reducing the number of the cooling channels while assigning higher flow rate for each channel will slightly lift the PEMFC temperature overall, but this strategy will result in more pumping power loss.