Chemical Treatment Method for the Aluminum Bipolar Plates of PEM Fuel Cells

In this paper, a chemical treatment method was developed to process the aluminum bipolar plates of proton electrolyte membrane fuel cells. During the surface treatment process, the chemical in the aluminum reacts with the electrolyte forming a metallic compound film with weak-atomic bonding. The adhesion property of this film is stronger than that of electroplating. This process is fast and much cheaper then physical vapor deposition processes. Anti-corrosion capability of the processed bipolar plates was analyzed using chemical and electrochemical methods. The corrosion curves computed by the linear polarization method showed the chemically modified film to have stable chemical and electrochemical characteristics. The surface and bulk electric conductivities, however, decreased slightly. Single cells of the bipolar plates, both with and without the chemically treated aluminum, were assembled for performance tests. The results showed that the single cell with chemically treated bipolar plates had a higher surface contact resistance and a decreased cell performance, but the cell life was longer. Future research efforts need to focus on improving the surface film conductivity and cell performance.