Study on performance enhancement and modeling of air-cooled proton exchange membrane fuel cell for different runner structure

Abstract

A long, rectangular shape is typically used to model the cathode runner of an air-cooled open-cathode proton exchange membrane fuel (AO-PEMFC) cell in order to supply air and dissipate heat. It is true that modifications to the cathode runner structure can impact hydrothermal control, which consequently affects the cell's output performance. The present research put forward an enhanced design for a suction-type annular bipolar plate structure and devised a 3D non-isothermal model to explore the consequences of modifying the cathode runner structural parameters of annular bipolar plate on the cell's performance output as well as the internal dispersion of heat, water, and oxygen. In addition, three cathode runner configurations—straight runner/fan-shaped rib, fan-shaped runner/straight rib, and fan-shaped runner/fan-shaped rib—were designed and their effects examined. The findings showed that the fan-shaped runner/straight rib configuration displayed the best temperature control capability (Hot spot temperature at cathode side exit: 36.3 °C, average temperature at the center surface of the film: 302.4 K, uniformity inside the cathode flow channel: 99.8 %) and achieved the maximum power density (contact resistance: 0.098 Ω-cm²) at the same current density conditions (0.8 A/cm²). The performance of the straight runner/fan-shaped rib was marginally inferior to that of the fan-shaped runner/straight rib, while the fan-shaped runner/fan-shaped rib configuration presented the poorest performance. Owing to the interaction of high air velocity and high electro-osmotic resistance inside the cathode runner, the fan-shaped runner/fan-shaped rib bipolar plate (relative humidity: 82.2 %) was prone to water loss from the fuel cell membrane electrode, thereby having an impact on the cell performance. Conversely, the fan-shaped runner/straight rib setup (relative humidity: 46.2 %) manifested the most excellent performance and kept an optimal water content. Overall, the findings of this investigation can be used as a significant source of guidance for optimization direction of AO-PEMFC.