Equation for General Description of Power Behaviour in Fuel Cells

Abstract

The analytical development of an equation that allows representing the general behavior of electrochemical cells and, in particular, proton exchange membrane fuel cells is presented in this work. The statement from which the proposed equation emerged was made by Rysselberghe where electrolytic cells work as power supply and around which an electrical current moves out of equilibrium. The data used to test the equation were taken from discharged slopes of PEM fuel cells constructed in the Institute of Scientific and Technical Research for the Defense with researchers from the Army Engineering Faculty and from literature. The equation P r = I r ( 2 - I r ) makes it clear that the relative power ( P r ) is a quadratic function of the relative current ( I r ) and shows a correlation coefficient close to 0.99 with respect to the experimental results of all data analyzed. It is important to remark that the parameters by which the prototypes were constructed were different: the amount and type of catalysts used, the active area, the material of bipolar plates, the type of electrolyte, the number of unit cells, and the different working conditions. In all cases and in spite of all the differences, which are very significant, the parametric equation proposed fits very well.