PEMFC MEA Manufacturing Quality Control R&D at NREL

High efficiency, low emissions, and fuel independence are some of the well-documented advantages of fuel cells as energy conversion devices.  The cost of fuel cell systems is a major stumbling block for many widespread, high volume applications such as automobiles, mass transit and remote power.  Typical costs from $4,000/kW to $5,000/kW.  However, backup power for telecommunications, and some industrial and military applications provide reliability incentives, productivity rewards and mission duration benefits that justify the high cost for fuel cells.  These early adopter applications demand the manufacture of high quality PEM fuel cells at production rates potentially approaching tens-of-thousands of fuel cells per month and hundreds-of-thousands fuel cell components per month.  While design and material considerations have a large contribution to cost, it is well understood that there must be a transition to high volume production of fuel cell systems, including membrane electrode assembly (MEA) components, i.e., membranes, electrodes, and gas diffusion layers, to enable economies of scale and drive down per-unit costs.  In-line quality control is a critical barrier identified by the fuel cell industry for continuous production of MEA components.  The National Renewable Energy Laboratory (NREL), with support from the U.S. Department of Energy Hydrogen, Fuel Cells, and Infrastructure Technologies Program, initiated a PEM fuel cell manufacturing program to develop in-line quality measurement and control for the production of MEAs.  An industry advisory team, formed in 2008 provides project recommendations for the development of MEA manufacturing quality control instrumentation.  In collaboration with other labs and universities, NREL will develop transfer functions that will provide the quality control for manufacturers to transition to high volume production.  The immediate objectives of the NREL project are to (1) develop and validate in-line quality control diagnostics for MEA component critical properties, (2) investigate the effects of manufacturing defects on MEA performance and durability, and (3) develop modeling tools to predict the effects of local variations in component properties.  This presentation will address ongoing work relative to the first two of the objectives noted above.  NREL is exploring commercially available in-line diagnostics as well as the applicability of an in-house developed optical diagnostic system for quality measurements of MEA component materials.  The in-house optical diagnostic system was originally developed for quality control in continuous manufacturing of photovoltaic components.  Rapid, large area (for example, on the order of 25 in²) measurements are possible with this instrument, making it an extremely attractive platform for in-line quality control measurement.  Thickness and composition measurement of proton exchange membranes is an initial focus of the work.  The optical diagnostic system is expected to be useful in the measurement of other parameters of interest to the component manufacturers, such as catalyst distribution.  In addition, in-line 2-dimensional imaging of component properties is being explored.  NREL is also investigating the impact of manufacturing defects on fuel cell performance and durability.  We are working with our industry advisory team to obtain component samples with actual manufacturing defects, and to create “designed” defects on “pristine” component samples, in order to establish how the defect affects performance and durability in single cells.  Both single cell and segmented single cell testing are being performed. The experimental segmented cell effort at the Hawaii Fuel Cell Test Facility will assess the feasibility of using segmented cell hardware to obtain spatially resolved performance data.