Assessing Durability of Elastomeric Seals For Fuel Cell Applications

Proton exchange membrane fuel cells typically consist of stacks of membrane electrode assemblies sandwiched between bipolar plates, effectively combining the individual cells in series to achieve the desired voltage levels. Elastomeric gaskets are commonly used between each cell to insure that the reactant gases are isolated; any failure of a fuel cell gasket can cause the reactants to mix and can lead to failure of the fuel cell. An investigation of the durability and lifetime of these fuel cell seals was performed by using accelerated characterization methods. A hydrocarbon sealant was tested in five different environments to simulate fuel cell conditions. Material properties such as secant modulus at 100% strain, tensile strength and strain at failure were determined using dogbone samples aged at several different imposed strains and aging times in environments of interest. Tearing energy was evaluated using trouser test samples tested under different rates and temperatures after various environmental aging conditions. Viscoelastic properties of these seals were analyzed using momentary and relaxation compressive stress tests. A viscoelastic and mechanical property characterization of these elastomeric seals under accelerated aging conditions could help understand their behavior and predict their durability in the presence of mechanical and environmental loading.