Fixed air flow-rate selection by considering the self-regulating function of low power air-cooled PEMFC stack

Abstract

In this study, it is found that the air-cooled proton exchange membrane fuel cell (PEMFC) has a self-regulating function in terms of its thermal and water balances within the fuel cell. Such a function enables the fuel cell's operation to be stable and efficient without any electronic controlling circuit to control the operating parameters. A small air-cooled PEMFC stack (15 cells with a rate power of 60 W) integrated with an axial fan is used for this experimental study to verify the self-regulating feature. The results show that the air-cooled open-cathode PEMFC stack can run stably and efficiently under a wide range of load currents at a fixed air flow rate. The best fuel cell performance and maximum system net power output are achieved at an air flow of 55.7 SLPM. To further validate the results, the temperature distribution and cell voltage distribution of the stack are simultaneously measured under different loads. The results demonstrate that the temperature and cell voltage of the stack are evenly distributed at the air flow of 55.7 SLPM. The present study may provide guidance in the design of a cooling subsystem of a small and compact fuel cell system incorporating an air-cooled open-cathode PEMFC.