There are many details to consider when choosing a fuel cell test station.
An important consideration is the nature of the research you wish to accomplish. If the goal of the research is to perform fundamental science and engineering analyses, such as evaluating new materials and components, electrode designs, etc., then a system for analytical capability is required. Important features of such a system include the performance (accuracy, stability, precision) of the control and measurement system. In fuel cell testing, this includes environmental and reactant control (flow rate, dew point/humidity, cell temperature, pressure, etc.) and electrical measurements (voltage and current). In addition, the instrumentation should have the capability for state-of-the-art analytical methods, such as continuous, real-time cell resistance measurement by Current Interrupt (iR) and High Frequency Resistance (HFR), Electrochemical Impedance Spectroscopy (EIS), and controlled voltage/current/power scanning, cycling, etc.
Collecting data is only half of the challenge. Verifying the integrity and significance of the data is also important. The quality of the data is only as good as the quality (accuracy, precision, etc.) as the equipment used to make the measurement. Repeatable and accurate humidity streams, cell fixture design and cell assembly, humidifier water quality, and other external conditions can affect the performance of the cell and the validity and quality of the research data.
For highly analytical testing, it is very important to consider and control all parameters of the testing setup. This is the type of experience and expertise that Scribner Associates is known for. It is also what we rely on when developing and marketing our test stations. For example, Scribner’s multiple current range electronic loads allow the researcher to match the current range of the load with the electrical current of the fuel cell. This increases measurement accuracy.
The current accuracy of the electronic load is 0.3% of the full scale (FS) range (e.g., 0.015 A for a 5 A FS and 0.15 A for 50 A FS setting). Therefore, the closer the load rating is to the expected performance of the cell or stack under test, the more accurate the results will be. Mass flow control and humidification systems may also be subject to unacceptable accuracy errors if not sized correctly. This is why it is difficult to perform testing on both low power and high power applications with one test system. It is more costly to build/buy a single test system capable of high performance on widely different power scales than it is to purchase two test systems each properly sized for the desired application.
Scribner’s products are engineered solutions, unlike some competitive products which integrate off-the-shelf general purpose components not designed for fuel cell testing. Scribner designs, tests and manufactures as many of the functional components of the system as is feasible to maximize performance and features, such as current interrupt (iR) and integrated EIS/HFR, that are important to the fuel cell researcher.
Testing which focuses on more functional parameters of fuel cell assemblies (most stack testing) has different needs that should be considered. Stack testing may require monitoring the electrical performance of each cell as well as multiple temperatures. Scribner Associates offers a stack monitor system for monitoring electrical performance of cells in a stack, as well as a data acquisition instrument to collect other temperatures and/or voltages for stack testing.
Scribner specializes in purpose-built electronic loads for fuel cell testing (890s) and integrated fuel cell test systems (850s) for single cell and small stack testing. We offer test loads up to 1kW/250A/50V with air cooling, and up to 3kW/500A/20V water-cooled systems. These test loads use the same FuelCell software as our 850 series units, and have an interface box for connections to fuel handling and safety equipment as designed and provided by the end user or system integrator.
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