Use of infrared matrix sensor for temperature measurement and monitoring of PEM/FC stacks

Abstract

Cells composing FC stacks can be subject to distinct operating conditions, resulting in different temperatures between them. This procedure establishes a non-homogeneous distribution along the stack profile. For a more precise monitoring and control purposes, the location of the cell’s temperature measurements has to be right on the surface of the stack profile. Thus, the greater the number of temperature measurement points on the stack profile, the greater is its control reliability and safer the operating conditions. As the fuel cell composition is almost entirely made of graphite and constantly subjected to an electrical potential difference, the direct contact of a temperature sensor with the stack must be avoided. The purpose of this paper is to propose a method to monitor the FC stack temperature distribution by an infrared matrix sensor. This procedure will obtain an increased number of measuring points avoiding any physical contact with the cells. This paper deals with information obtained from an infrared matrix sensor with its calibration handled by software. After processing the sensor's temperature data, they are displayed as a thermal image. With this, the temperature control of the stack can act in such a way that it does not reach critical levels that could compromise its useful life. In this text, a sensor calibration procedure is presented together with data validation through experimental results. In the tests using this technique was verified that about 84% of the normal error distribution around the maximum temperature was kept between ± 2 °C, therefore within tolerable limits.