Three-dimensional finite element analysis of PEMFC components under clamping and thermal loading

Thermo-mechanical behavior of proton exchange membrane fuel cells (PEMFCs) under clamping and thermal loading, accounting for the temperature- and relative humidity-dependent mechanical properties of the membrane, is essential for their electrochemical performance, durability, and lifespan. A full-scale three-dimensional finite element model of a PEMFC with a symmetric double serpentine flow field was established to examine the thermo-mechanical response of the cell components. This study systematically evaluates the thermo-mechanical stability of the Nafion 112 membrane over temperatures from 25 to 85 °C and clamping torque values from 3 to 10 Nm, while accounting for the temperature- and relative-humidity-dependent Young's modulus of the membrane over an RH range of 30–90%. Among the operating parameters investigated, clamping torque was found to be the most significant factor affecting the thermo-mechanical response of the PEMFC, greatly influencing both stress levels and their distribution. At a temperature of 65 °C and relative humidity of 90%, along with a clamping torque of 10 Nm, the membrane demonstrated maximum stress levels of 35.21 MPa for mechanical stress, 1.81 MPa for thermal stress, and 33.46 MPa for thermo-mechanical stress. Decreasing the clamping torque from 10 Nm to 3 Nm significantly reduced the membrane's thermo-mechanical stress to 9.56 MPa, which is an approximate reduction of 70%.