Integration of Micro Array Sensors in the MEA on Diagnosis of Micro Fuel Cells

Abstract

The temperature and humidity conditions of a membrane electrode assembly (MEA) determine the performance of fuel cells. The volume of traditional temperature and humidity sensors is too large to allow them to be used to measure the distribution of temperature and humidity in the MEA of fuel cells. Measurements cannot necessarily be made where required. They measure only the temperature and humidity distribution outside the fuel cells and yield results with errors that exceed those of measurements made in MEA. Therefore, in this study, micro-electro-mechanical-systems (MEMS) fabrication technology was employed to fabricate an array of micro sensors to monitor in situ the temperature and humidity distributions within the MEA of fuel cells. In this investigation, an array of micro temperature and humidity sensors was made from gold on the MEA. The advantages of array micro gold temperature and humidity sensors are their small volume, which enable them to be placed on MEA and their high sensitivity and accuracy. The dimensions of the temperature and humidity sensors are 180μm × 180μm and 180μm × 220μm, respectively. The experiment involves temperatures from 30 to 100 °C. The resistance varied from 23.084 to 28.196 /. The experimental results reveal that the temperature is almost linearly related to the resistance and the accuracy and sensitivity are less than 0.3 °C and 3.2×10-3/°C, respectively. The humidity sensor showed that the capacitance changed from 15.76 to 17.95 pF, the relative humidity from 20 to 95 %RH, and the accuracy and sensitivity were less than 0.25 %RH and 0.03 pF/%RH.