From the cell to the stack. A chronological walk through the techniques to manufacture the PEFCs core

In the recent decades, researchers have been focussing more and more on renewable energy because of the known climate crisis that will occur in the near future. One possible solution is the use of fuel cells that generate clean energy. Regarding fuel cell technologies, polymer electrolyte fuel cells (PEFCs) are widely used for portable, stationary or automotive applications as well as backup systems for emergency situations. To build a full PEFC stack, a single cell is used, which is then stacked with more similar cells (the number of cells depends on the electrical power required) and are then integrated into the final product. In a cell, there are two parts that deserve special attention: membrane electrode assembly (MEA) and bipolar plates (BPs). This paper is dedicated to carry out detailed review of processes involved in these two parts, describing the catalyst deposition techniques and BPs manufacturing methods. Finally, a discussion of how to assemble the cells to build a stack of suitable power is included. The review shows the different techniques in chronological order to be able to understand where the fuel cells technology started, and all of the new developments that have been made over time. Each of the techniques has been studied separately in order to provide a comprehensive analysis of the various possible methods found in the scientific literature. After a description and analysis of each technique, a comparative evaluation has been carried out to highlight the most important characteristics of each technique. The review also shows that for fuel cells manufacturing technology to achieve good rates of accuracy, mass production and homogeneity, research should be aimed at achieving less restrictive manufacturing and environmental conditions, and equipment is required with lower costs.