Modular single cell and assembled cell stack of a proton exchange membrane fuel cell

The present invention relates to a novel structure of a single cell module of a proton exchange membrane fuel cell (PEMFC), comprising an anode bipolar plate, a cathode bipolar plate and a membrane electrode assembly (MEA) sandwiched therebetween. The MEA is substantially disposed on a central portion between the anode and cathode bipolar plates. A desired amount of silicon rubber (RTV), by means of programmed automatic robotic arms, is applied to a circumferential portion between the anode and cathode bipolar plates to seal, cushion and position the anode bipolar plate and cathode bipolar plate under a pre-determined compression pressure after the RTV is cured, thereby forming an integral single cell module. According to the structural concept, a plurality of the single cells can be customized to form a cell unit by superimposing them in sequential order, of which an upper surface of the anode bipolar plate and/or a lower surface of the cathode bipolar plate are/is formed with grooves on their circumferential portions for receiving the RTV so as to provide a sealing, cushioning and positioning contact, and achieve an optimal compression pressure among the layered single cells.