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<p>Gas diffusion layers (GDLs) are an important component of polymer electrolyte membrane (PEM) fuel cells. They are around 100–400&#xa0;µm thick in typical fuel cell design, which contribute a considerable volume in fuel cell and influence the stack’s volumetric power density. Thus, thin GDLs are considered a viable strategy to increase fuel cell power per volume, which is crucial to fuel cell automobile application. The impacts of the GDL physical processes on cell performance are investigated, with a focus on thin GDLs, through advanced three-dimensional (3-D) non-isothermal two-phase modeling. The 3-D model is based on the conservation equations for mass, momentum, heat, species (oxygen, hydrogen, water, etc.), electron, and proton, coupled with the electrochemical kinetics. It is found that thin GDLs can deteriorate oxygen starvation under the land, reducing local and overall cell performances. In addition, the temperature spatial variation in fuel cell increases when reducing GDL thickness, which can lead to dryout of local GDL and hence electrode in the cathode. For the 25&#xa0;µm thick GDL, the temperature variation can be as high as 17&#xa0;°C at 1.3&#xa0;A/cm<sup>2</sup>, raising a major concern of local hot spot formation. Analysis is presented to explain a few important physical processes in GDLs, including the in-plane heat removal by GDL, vapor diffusion driven by temperature gradient, and gas flow in GDLs. The 3-D distributions of reactant and product species and temperature are disclosed, showing that advanced modeling is important to assist thin GDL design for fuel cells.</p>

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Thin Gas Diffusion Layer for Polymer Electrolyte Membrane Fuel Cell: Three-Dimensional Distribution and Performance Loss

  • 期刊论文

  • 发表日期：

    2025年7月5日

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  • Sungchan Cho,
  • Yuehang Dai,
  • Hongkun Li,
  • Yun Wang

摘要

Gas diffusion layers (GDLs) are an important component of polymer electrolyte membrane (PEM) fuel cells. They are around 100–400 µm thick in typical fuel cell design, which contribute a considerable volume in fuel cell and influence the stack’s volumetric power density. Thus, thin GDLs are considered a viable strategy to increase fuel cell power per volume, which is crucial to fuel cell automobile application. The impacts of the GDL physical processes on cell performance are investigated, with a focus on thin GDLs, through advanced three-dimensional (3-D) non-isothermal two-phase modeling. The 3-D model is based on the conservation equations for mass, momentum, heat, species (oxygen, hydrogen, water, etc.), electron, and proton, coupled with the electrochemical kinetics. It is found that thin GDLs can deteriorate oxygen starvation under the land, reducing local and overall cell performances. In addition, the temperature spatial variation in fuel cell increases when reducing GDL thickness, which can lead to dryout of local GDL and hence electrode in the cathode. For the 25 µm thick GDL, the temperature variation can be as high as 17 °C at 1.3 A/cm2, raising a major concern of local hot spot formation. Analysis is presented to explain a few important physical processes in GDLs, including the in-plane heat removal by GDL, vapor diffusion driven by temperature gradient, and gas flow in GDLs. The 3-D distributions of reactant and product species and temperature are disclosed, showing that advanced modeling is important to assist thin GDL design for fuel cells.