Deformation Mechanics of Fuel Cell Gas Diffusion Layer: Cyclic Response and Constitutive Model

Abstract

The deformation mechanics of a typical gas diffusion layer using an experimental and advanced modeling technique is reported. The experimental cyclic response is observed similar to pseudo-elastic materials with highly nonlinear loading/unloading. The cyclic compressive mechanical response of gas diffusion layer is modeled to be the outcome of cumulative changes in deformation kinematics of matrix and fiber fractions. The individual mechanisms necessitating the energy dissipation, residual strain, and stress softening during cyclic mechanical response are related to nonlinear hyperelastic matrix with the damage function and inelastic activation function at the interface of constituents. The model predicts highly nonlinear elastic loading, residual strain, hysteresis, and damage quotient associated with stress softening as a function of several cycles. The significant takeaway from this study is in terms of quantifying strength, inelastic nature of individual constituents. The proposed model is simulated for low-level altering stresses of up to twenty cycles. The results show the build-up of residual strains and hysteresis as a function of fuel cell clamping pressure.

Towards Reliable Prediction of Performance for Polymer Electrolyte Membrane Fuel Cells via Machine Learning-Integrated Hybrid Numerical Simulations

“…The heterogeneity of GDL is not considered well during CFD simulation for the sake of simplicity. However, porosity, permeability, bulk resistance, and interfacial contact resistance (ICR) of GDL greatly affect the performance of PEMFC [281][282][283]. Nitta et al [218] considered heterogeneous GDL in their 2D modeling and obtained better cell performance by optimizing porosity, effective thermal conductivity, and effective gas diffusion coefficient.…”

Numerical Investigation of the Irreversible Behavior of GDL Under Cyclic Hygrothermal Loading

“…26 Kleemann et al 27 proposed an orthotropic model with a fit of Young's modulus measured during compression. Some studies have used hyperelastic model 12,38,39 and Koorata 40 performed a comparison of several hyperelastic models to propose an advanced model that takes into account the irreversible strain of the GDL and the hysteresis resulting from the loading and unloading cycles. Due to the incompressibility hypothesis associated with these hyperelastic models, the in-plane stress caused by compression must be carefully considered, and the out-of-plane Poisson's ratio is assumed to be null due to the high porosity of the material.…”