Effects of pore size gradient in the substrate of a gas diffusion layer on the performance of a proton exchange membrane fuel cell. (1st July 2015)

• Record Type: Journal Article
• Authors: Oh, Hwanyeong; Park, Jaeman; Min, Kyoungdoug; Lee, Eunsook; Jyoung, Jy-Young
• Is Part Of: Applied energy. Volume 149(2015:Jul. 01)
• Page Start: 186
• Page End: 193
• Publication Date: 2015-07-01
• Subjects: Proton exchange membrane fuel cell -- Gas diffusion layer -- Substrate -- Pore size gradient -- Capillary pressure gradient -- Water management; Power (Mechanics) -- Periodicals; Energy conservation -- Periodicals; Energy conversion -- Periodicals; 621.042
• DOI: 10.1016/j.apenergy.2015.03.072
• Languages: English
• ISSNs: 0306-2619

Abstract

Highlights: The dual layered substrate with different carbon fibers formed a pore size gradient. The gradient increased the cell performances under various humidity conditions. The water management was improved by balancing the capillary pressure gradient. Abstract: The proton exchange membrane fuel cell (PEMFC) is one of the up-and-coming power sources for automotive vehicles. To generate a stable performance during driving, the PEMFC needs to achieve an optimized water management under various humidity conditions. Being the path for the two-phase flow of fuel, air, and water, the gas diffusion layer (GDL) is a critical component, which influences water balance. In this study, a pore size gradient structure is introduced in the substrate of a GDL to control the local capillary pressure gradient, which is the driving force of the water flux inside the PEMFC. Through measurements of steady-state performance, transient response, voltage instability and electrochemical impedance spectroscopy, it was found that the pore size gradient structure improves the cell performance regardless of the relative humidity conditions used (50% and 100%). Furthermore, it is possible to hold the water on the membrane for higher ion conductivity and drain it toward the channel to secure gas supply toward the catalyst layer. In addition, it was also confirmed that the structural change enhances the bending stiffness of the GDL.