Durability issues of the PEMFC GDL and MEA under steady-state and drive-cycle operating conditions

摘要: Component durability remains, in most cases, a prohibitive barrier to widespread commercialization of stationary and automotive PEMFC systems. Aspects this topic are difficult quantify improve not only because the quantity duration testing time required (i.e., up several thousand hours or more), but also fuel cell stack is system components (electrocatalysts, membranes, gas diffusion media, bipolar plates, gaskets) for which degradation mechanisms, component interactions, effects operating conditions fully understood. Simply acquiring 5000 test data on single will lead comprehensive understanding mechanisms. The individual must be well-characterized during determine mechanisms that occur over long periods. Chemical an environment likely interconnected due trace compounds leach out one subsequently affect another. For reason, separate characteristics each well This study focuses fundamental two key repeating units, membrane electrode assembly (MEA) layer (GDL). Little has been published thismore » area, as historical emphasis performance improvement beginning life short-term data). In work it desired develop initial basis transitioning towards longer-term (1000-5000 hours) behavior existing technologies, rather than more common model continual next-generation technologies based few 10's 100's data. Even though given application may have multiple power set points, operate nearly all at point. Therefore, important design considerations should reflect steady-state conditions, where temperature, flows, voltage, current density, etc., maintained many time. Automotive applications other hand, require changes load, points respond simultaneously. Despite drastic difference between lifetime targets stacks (5000 vs. 40,000 hours, respectively), transient point induce significantly aggressive MEA GDL materials. Thus, cells carried simulate drive cycle with continuously varying transportation applications, yields information about how behave under appreciably different characteristics.« less