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Mathematical Modelling and Simulation of Polymer Electrolyte Membrane Fuel Cells. Part I: Model Structures and Solving an Isothermal One‐Cell Model
Author(s) -
Hertwig K.,
Martens L.,
Karwoth R.
Publication year - 2003
Publication title -
fuel cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.485
H-Index - 69
eISSN - 1615-6854
pISSN - 1615-6846
DOI - 10.1002/fuce.200290004
Subject(s) - electrolyte , coolant , isothermal process , materials science , proton exchange membrane fuel cell , work (physics) , electrode , voltage , mechanics , membrane , polymer , current (fluid) , power density , biological system , nuclear engineering , power (physics) , mechanical engineering , thermodynamics , chemistry , composite material , electrical engineering , engineering , physics , biochemistry , biology
Amongst the various types of fuel cells, the polymer electrolyte membrane fuel cell (PEM‐FC) can be used favourably in vehicles and for in house energy supply. The focus of the development of these cells is not only to provide cost‐effective membranes and electrodes, but also to optimise the process engineering for single cells and to design multi‐cell systems (cell stacks). This is a field in which we have successfully applied the methods of mathematical modelling and simulation. Initially, in this work, a partial model of a single membrane‐electrode unit was developed in which the normal reaction technology fields (concentration, temperature, and flow‐speed distributions) were calculated, but also the electrical potential and current density distribution in order to develop model structures for technically interesting PEM‐FC. This allows the simulation of the effects that the geometric parameters (electrode and membrane data and the dimensions of the material feed and outlet channels) and the educt and coolant intake data have on the electrical and thermal output data of the cell. When complete, cell stacks consisting of a number of single cells, most of which have bipolar switching, are modelled the distribution of the gas flows over the single cells and the specific conditions of heat dissipation must also be taken into consideration. In addition to the distributions mentioned above, this simulation also produces characteristic current‐voltage and power‐voltage curves for each application that can be compared with the individual process variations and cell types, thus making it possible to evaluate them both technically and economically. The results of the simulation of characteristic process conditions of a PEM‐FC operated on a semi‐technical scale are presented, which have been determined by means of a three‐dimensional model. The distributions of the electrical current density and all component voltage drops that are important for optimising the conditions of the process are determined and also the water concentration in the membrane as an important factor that influences the cell’s momentary output and the PEM‐FC’s long‐term stability.