Proton-exchange membrane fuel cells or polymer electrolyte membranes (PEM fuel cells) work by converting the energy released from hydrogen and oxygen reactions into electrical energy. In PEM fuel cells, a membrane is used that performs an important proton transfer function, preventing the flow of electrons. Platinum acts as a catalyst in hydrogen fuel cells by splitting hydrogen molecules. Platinum mixed with soot and water is superimposed on the membrane of the fuel cell.
Let's take a deeper look at the design of these fuel cells and how this material is masked onto the membrane. Platinum plays a central role in the operation of the PEM fuel cell; it is responsible for the oxidation of hydrogen and the reduction of oxygen content, since it must cover the maximum surface area of the membrane in order to be exposed to the injected gas itself. It is also important to maximize the surface area of the platinum catalyst particles using the smallest particles. The smaller the size, the larger the surface area that is subjected to the injected gas. Finally, it is important that the platinum particles are laid sequentially and in such a way as to avoid aggregation or agglomeration.
The next goal to be observed in the construction of a PEM fuel cell is the thickness of the platinum coating of the catalyst. It is necessary to create a uniformly uniform or uniform film thickness in order for the filter to have the same amount of hydrogen. If there must be an inconsistent platinum layer, a less dense section will have a lower oxidation rate, while thicker than a normal layer may cause other problems. Here, determining the proper density of a platinum film is a critical issue, so it is important that the coating of platinum soot on the membrane of the fuel cell is very homogeneous for optimal hydrogen conversion. The density of platinum plays an important role in determining the amount of gas reaching the hydrogen fuel cell membrane. The combination of platinum soot should be such as to ensure an acceptable degree of contact between the gas and the membrane. Obviously, the dam layer will provide a measure of resistance leading to a decrease in the contact speed of platinum and gas, as well as a finely lower chemical reaction rate. A layer of a smaller layer will lead to hot spots and other problems. Thus, uniformity is required, both in the platinum bundle and in the carbon sheet.
It has been found that when pressing, using a knife edge and printing methods, these non-uniform coating thicknesses and / or hot spots on fuel cell membranes. Ultrasonic spraying technology is the ideal solution for coating the polymer membrane with a platinum catalyst. First, platinum is, of course, expensive materials and ultrasonic spray nozzles due to their soft or low speed ahead, minimizing rebound or spraying. Secondly, coating applications must be extremely accurate in order to provide optimal results that can be achieved with ultrasound. Finally, the coating process should not damage what you are trying to cover. Through the press methods, the internal device can be harmed by long-term environmental impact. While rolling processes, also subject to prolonged exposure to the environment, can lead to agglomeration of platinum particles. The process of hydraulic spraying is much more suitable, but it also has many pitfalls. Dispersion using hydraulic spraying is often inconsistent, which can lead to hot spots. There is also an unnecessary waste of platinum due to the high velocity of the liquid, which leads to a “rebound” of the liquid.
Thus, ultrasonic technology provides an important coating uniformity, maintains quality and reduces the overall cost of production by minimizing waste.
