Fuel-cells are electro-chemical energy-transformation devices, which transform the chemical energy of the fuel directly into electrical energy. Fuel-cells have been used in space- and military applications for decades as energy sources and are nowadays built into vehicles and numerous electronic devices. The output of these devices covers a wide range, from very low output (1 W) to power-plant applications (10 MW). To increase efficiency of the system as a whole and guarantee stability of performance it is necessary to improve upon the existing cell-types. To discover problems and determine optimal parameters test devices are needed.
Kontakt-Elektro Ltd. in Pécs is also in the business of developing fuel cells. Here I had the opportunity to join in a project to develop a test device for fuel cells. My task was to write a program able to acquire the polarization characteristic.
The firm chose the LabVIEW environment as the programming language because of the wide range of supported hardware. First I learned this programming language. The program had to control an artificial load via GPIB interface. After familiarizing myself with the artificial load I wrote the program and acquired the polarization characteristic of a 500W Ballard fuel-cell. The program performed according to my expectations, the acquired characteristic matched the characteristic in the datasheet of the device nearly completely. As the gas management module of the test device was not yet completed the temperature and gas parameters of the cell were not optimal. This was the cause of the slight deviation of the measured graphs from the manufacturer’s specifications. The voltage curve gives fundamental knowledge of the cell’s behavior and aptly demonstrates the voltage loss caused by chemical processes and the ohmic voltage loss of the cell. Deviation from the theoretical graphs can help to indicate weaknesses in the fuel cell design. This information can be crucial during development.
During later development the finished program can easily be amended with the currently missing gas management. This will enable the polarization characteristics give more reliable insight into the voltage relations of fuel cells.