Numerical simulation reveals the cooling characteristics of water-cooled proton exchange membrane fuel cell stack

Cooling is a critical factor affecting the performance of high-power proton exchange membrane fuel cell stacks, yet research at the stack scale remains scarce. In this study, by combining a three-dimensional stack-scale cooling flow field model with a flow network model, the coolant flow characteristics within the stack and their influence mechanisms on stack performance were analyzed. The results demonstrate a clear trade-off between net power output and operational uniformity. Within the investigated flow rate range meeting the cooling requirements of the stack, a lower coolant flow rate improves flow uniformity and minimizes parasitic power. Under the operating conditions considered in this study, the decrease in membrane water content caused by increased stack temperature at lower coolant flow rates is the primary factor affecting stack performance. Conversely, a higher flow rate can improve temperature uniformity and reactant distribution, particularly anode side, reducing hydrogen flow non-uniformity by up to 6.49% at 1.3 A·cm−2. This research provides both model-based and theoretical support for developing high-performance cooling flow fields and strategies that balance immediate power output with long-term stack durability.