Optimization of control strategy for air-cooled PEMFC based on in-situ observation of internal reaction state

Air-cooled proton exchange membrane fuel cell (PEMFC) is a promising electrochemical device in fields of unmanned aerial and light-duty ground vehicles, with the virtues of simple system, low parasitic power and low cost. However, the significantly uneven distribution of internal reaction state of air-cooled PEMFC greatly limits the output performance and stability of the cells. In this study, a PCB test board for the in-situ observation of cell temperature and current density is designed and applied in fuel cells. The result shows that when the average current density is 500 mA/cm2,the difference of temperature and current density reach 20 degrees C and 400 mA/cm2, respectively. For the optimization of uniformity of reaction state, the effects of hydrogen pulsing interval, hydrogen supply mode, fan configuration and air inlet speed are experimentally explored. Based on the observed results of the PCB test board, optimization proposals of control strategy for air-cooled PEMFC are given: 1) A 30-s pulsing interval of hydrogen is preferred due to its little changes on current density distribution while significant increasement of hydrogen utilization rate. 2) The proposed bidirectional hydrogen flow improves the reaction uniformity, and reduces the fluctuation of current density during hydrogen pulsing discharge; 3) Compared to two paralleled fans, employing a single fan helps to improve the temperature uniformity, with the standard deviation of temperature from 8.9 degrees C to 6.7 degrees C; 4) Medium velocity of air inlet speed is preferred due to poor temperature uniformity at low velocity, and low water content at high velocity.

Automated summary

Air-cooled proton exchange membrane fuel cells (PEMFCs) have the advantages of simple system, low parasitic power, and low cost. However, the uneven distribution of internal reaction state limits their performance and stability. In this study, a PCB test board is designed to observe the temperature and current density of the cells. Optimization proposals for controlling air-cooled PEMFCs are given based on experimental exploration of hydrogen pulsing interval, hydrogen supply mode, fan configuration, and air inlet speed.