|Liquid water content of an operating PEM fuel cell. Red color is more water, blue is less. Source: Sandia.|
Researchers at Sandia National Laboratories are working to understand water management and performance degradation in hydrogen-fueled PEM (proton exchange membrane) fuel cells—two key areas that need to be addressed before PEM fuel cells can be used more routinely in transportation and/or for home power.
One, Ken S. Chen, is developing computational models to describe the phenomena while the other, Mike Hickner, is performing physical experimentation.
The work is internally funded through a three-year Laboratory Directed Research and Development (LDRD) grant to tackle key technical challenges. Sandia is a National Nuclear Security Administration laboratory.
“A natural byproduct of using hydrogen and oxygen to produce electricity in a PEM fuel cell is water [with waste heat being the other]. One challenge is maintaining the proper amount of water in a PEM fuel cell. Sufficient water in the membrane is needed to maintain its conductivity, whereas too much liquid water can result in flooding the cathode gas diffusion layer, which prevents reactant oxygen from reaching catalytic sites and causes performance deterioration.—Ken Chen, project principal investigator
The two scientists have obtained some nice feedback between the experiments and analyses. The intent is to build a computational tool that can be used in designing fuel cells, eliminating the need to do experiments on every single part of them.
For the past couple of years Chen and Hickner have focused mainly on liquid water transport, developing a PEM fuel cell model that can be employed to simulate a fuel cell’s performance, and performing diagnostic tests on fuel cells for phenomena discovery and model validation.
Next they will tackle the key technical issues of performance degradation or durability, including performance degradation under normal operating conditions and under freezing operating conditions.
Bruce Kelley, project manager for the PEM Fuel Cell LDRD and manager of Sandia’s Chemical Biological Systems Department, says the project was developed specifically to leverage Sandia’s capabilities in multi-physics modeling and membrane materials to develop broader capabilities with applicability to fuel cells and other related technology areas.