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Fuel cells are an important enabling technology for the hydrogen economy and have the potential to revolutionize the way we power our nation, offering cleaner, more-efficient alternatives to the combustion of gasoline and other fossil fuels. NREL's work supports DOE's focus on core technologies to improve fuel cell systems and the various subsystems and components that comprise them. Specific research areas at NREL include:
Fuel Cell System Analysis
Robust and durable fuel cell designs are necessary for fuel cells to successfully compete with existing mature technologies. With the complex design requirements for fuel cell systems, the need for innovative design and analysis tools is apparent now more than ever. NREL analysts are using a variety of simulation and analysis tools to identify critical design issues for fuel cell vehicles and systems. In addition, NREL works with industry to share and apply robust design techniques, optimization tools, and CAE tools to address the issues of durability, cost, and efficiency.
NREL's Vehicle Systems Analysis Team uses ADVISOR, a complete vehicle systems analysis tool, to understand fuel cell vehicle design barriers and opportunities and to simulate vehicles based on DOE's fuel cell technical targets. Combined with design of experiments methods, the sensitivities of various technical targets and the relative importance of each can be determined. In the past, battery sizing for fuel cell hybrids, fuel economy impacts of fuel cell reformer startup, and water management over typical drive cycles have been analyzed. Optimization with respect to water and thermal management under typical and extreme operating conditions are the next areas slated for evaluation.
NREL has also developed and demonstrated advanced CAE methods, which allow selection of the key design parameters that most influence the quality of new technologies. Sensitivity and optimization algorithms have been used to examine the feasibility of and derive the best choice of the design parameters. Probabilistic modeling of material, loading, and manufacturing variations is used to develop robust designs that achieve the desired quality level (i.e., six-sigma) while meeting all the necessary performance targets. NREL has recently applied these techniques with industry partners such as Plug Power and Ballard Power Systems to achieve robust designs of fuel cell, reformer, and heat exchanger components.
Stationary fuel cell systems are evaluated using NREL's Hybrid Optimization Model for ElectricRenewables (HOMER). HOMER is a computer model that simplifies the task of evaluating design options for both off-grid and grid-connected power systems for remote, stand-alone, and distributed generation applications. It can look at combinations of photovoltaics, wind, batteries, micro-hydro, and any type of engine-generator (reciprocating engines, micro-turbines, or fuel cells) powered by any fuel, including biomass. HOMER identifies the least-cost system for particular applications by simulating the hourly performance of different system configurations and ranking them by net present cost. Sensitivity analyses are used to evaluate variations in technology costs and energy resource availability, and to identify the market impacts of planning and policy decisions.
Recent presentations and publications:
- Cost Analysis of PEM Fuel Cell Systems for Transportation, E.J. Carlson et al. (2005) (PDF 1.87 MB) Download Adobe Reader.
- PEM Fuel Cell Freeze and Rapid Startup Investigation, Ahmad Pesaran (2005) (PDF 5.23 MB)
- Fuel Cell Vehicle Systems Analysis, Tony Markel et al. (2003) (PDF 1.42 MB)
- Fuel Cell Vehicle Systems Analysis, Tony Markel (2002) (PDF 550 KB)
Contact: George Sverdrup (303) 275-4433
Fuel Cell Component Materials
The potential benefits of fuel cells are significant; however, many challenges must be overcome before fuel cell systems will be a competitive alternative for consumers. Cost, performance, and durability of fuel cell components are key areas that need to be addressed. Vehicle systems operate more efficiently at higher temperature, however, the membrane materials used in current PEM fuel cells cannot withstand these higher temperatures. NREL is developing new specialized materials that can resist high temperatures and novel methods that can reduce catalyst poisoning.
One area of research is the evaluation of inorganic solid state proton conducting systems for high temperature fuel cell membranes. The goal of this research is to acquire an improved fundamental understanding of a class of inorganic proton conductors (heteropoly acids [HPA] and their salts) that exhibit high proton conductivity at elevated temperatures (well above 100°C) and to apply that understanding to fuel cell membrane technology. The HPA exhibit proton conductivity among the highest measured in the solid state, more than an order of magnitude higher than Nafion. The ultimate goal is to develop HPA-based composite materials that can be combined with polymers and other potential supports to manufacture thin films as membrane materials for use in fuel cells.
The second area of research is the evaluation of corrosion protection of metallic bipolar plates for fuel cells. The goal of this research is to investigate and develop metal bipolar plate materials and coatings that are low-cost, lightweight, corrosion-resistant, gas impermeable, and amenable to mass manufacturing. NREL's experience in conducting oxides, which have been used in various types of solar cells, and expertise in corrosion testing are the foundation of this effort. Based on this experience, possible suitable materials (i.e., offer appropriate corrosion protection and give high conductivity) for this application include tin oxide, indium tin oxide, and zinc oxide.
Contact: John Turner (303) 275-4270
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