Abstract:

In order to improve the uniformity of temperature and reactants between different cells in the stack， thus improving the stack performance and extending the stack life， an improved scheme of setting different gradient porosity in gas diffusion layers of different cell units in the stack is proposed in this paper. A three-dimensional， non-isothermal， single-phase short stack model with five layers of cell units is established for analysis. It is found that the scheme with porosity of 0.4-0.5-0.6-0.5-0.4 can minimize the difference of temperature， oxygen， water molar concentration， membrane current density between the edge layer and the intermediate layer cell unit； thereby improve the internal uniformity of the stack， which is also the same trend under the operating conditions of gas shortage.

Key words: proton exchange membrane fuel cell, fuel cell stack, numerical simulation, gas diffusion layer, layered design