Coupling optimization study of slope step flow field and gas diffusion layer porosity distribution in proton exchange membrane fuel cells based on Taguchi method

The design of flow channels and gas diffusion layers in proton exchange membrane fuel cells is crucial for the mass transfer and electrochemical performance of the fuel cell. This study proposes a slope stepped flow channel design and establishes a three-dimensional two-phase isothermal fuel cell model. On this basis, the influence of slope step structure and gradient porosity distribution on the performance of fuel cells is studied. This study focuses on the influence of slope step flow field structure and gas diffusion layers porosity distribution on the performance of proton exchange membrane fuel cells. In this study, 16 experimental combinations are designed using the Taguchi method to investigate the mapping relationship between the slope step flow field structure, gradient porosity distribution, and proton exchange membrane fuel cells output performance. Finally, by analyzing the sensitivity of each parameter, the optimal parameter combination is determined to be a porosity of 0.6 near the flow channel, a porosity of 0.5 near the catalyst layer, a gas diffusion layer thickness of 0.2 mm, a slope angle of 2°, and a slope projection length of 2.1 mm. After coupling optimization, the maximum current density of the fuel cell increased by 19.5 % and the net power increased by 16.2 % compared to parallel flow fields. In addition, compared with single component optimization, the coupling optimization of slope step flow channels and gradient porosity distribution can make the fuel cell have a more uniform material distribution and improve the drainage capacity of the fuel cell. Compared with the parallel flow field, the optimized fuel cell showed a 25 % increase in average oxygen concentration and an 8.2 % decrease in average liquid water saturation. [Display omitted] •A design scheme for a sloped step flow field is proposed.•An effective porosity distribution scheme for GDL is proposed.•A coupling-optimized design solution with the best performance was obtained.•Demonstrate the advantages of multi-component optimization over single-component optimization.