Gaskets stack components

The function of the stack-compression hardware is to fasten stack components with a defined and homogeneous pressure. If these requirements are not accurately fulfilled, the function and the durability of the stack will be influenced negatively. The MEAs and the bipolar plates need to be fixed in accurate positions and the compression of gaskets needs to be safe and homogeneous. If the pressure is too high, it will cause mechanical failure of the membrane or of the bipolar plate. If the pressure is too low. 

Compressive seals, which typically utilize materials such as sheet-structure silicates to act as a gasket between components, can help to improve the stack s tolerance to thermal expansion mismatch between various stack components. A compliant high-temperature material is placed between the two sealing surfaces and compressed, using a load frame external to the stack, to accomplish sealing. 

Fig. 3 Components of the polymer electrolyte fuel cell (PEFC) membrane electrode assembly (MEA) on the left, including separator plates and gasket. A schematic of a PEFC stack is shown on the right, comprising a number of single cells in series...

A PEMFC uses a solid membrane that conducts protons as the electrolyte. Since it can start at ambient temperatures instantly, it is ideal for backup, portable, and motive power applications. The most important technologies concern the stack (like the heart of a human being) and the system controls (like the brain of a human being). The key components in a stack include the catalyst, PEM, GDM, plates, and gasket, while the controls include the operation algorithm, software, and electronic circuits. A fuel cell also needs various auxiliary components such as fans, blowers, compressors, pumps, heat exchangers, humidifiers, converters, valves, sensors, and batteries to work. A fuel cell system involves multidisciplinary skills and knowledge, and therefore it requires a team effort to develop. 

Within the system, about half of the cost arises from the stack, and the other half from the BOP. The cost of the major components of the 25 per kW stack (2010 status) is plotted in Figure 8.5. The largest cost comes from the catalyst layers due to the use of precious metals, followed by the plates because of protective coatings against corrosion. The cost of the PEM, GDM, and gaskets are quite similar. 

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