Stainless steel fuel cell bipolar plate and its experimental and simulation
|School||Shanghai Jiaotong University|
|Keywords||Stainless steel bipolar plates Proton exchange membrane fuel cell Surface Modification Flow field Experiment Simulation|
Bipolar plate is a proton exchange membrane fuel cell is one of the key components, not only affect the battery performance, but also affect the cost of the battery, a fuel cell industry bottlenecks. Because of its excellent corrosion resistance of stainless steel and easy processing properties, often selected for the metal bipolar plate materials PEMFC. However, stainless steel bipolar plates for PEMFC corrosion under operating conditions to become the main factor restricting its application, while the passivation film, increasing the contact resistance inside the battery. Therefore, stainless steel bipolar plates for PEMFC, it must be surface modification, a conductive layer formed on the surface protective layer of stainless steel at the cathode enhanced oxidizing environment of the anode and oxidation resistance in an acidic environment, reducing corrosion resistance. In order to improve the surface plating is not conducive to corrosion pinhole phenomenon, this paper composite coating process, first in 304L stainless steel silver as the underlying surface, and then electroplating or sputtering a thin gold layer, and thus play a cover pinhole achieve densification. After modification of the surface of the stainless steel bipolar plate surface after coating interface, good conductive properties of the composite: the analog assembly of the fuel cell stack under the conditions obtaining and measuring the contact resistance of the carbon paper Toray060 of 2.7 ~ 3.1mΩ · cm 2 sup>, about · contact resistance of stainless steel is untreated fifteenth. Corrosion tests show that, compared to untreated 304L stainless steel body have been significantly improved: in 0.05mol/LH 2 SO 4 5 × 10 -6 sup> mol / L HF simulated fuel cell corrosion solution, silver - plated composite coatings and silver - gold sputtered composite layer stainless steel its corrosion potential compared to untreated were increased by 0.45V and 0.49V, corrosion current density decreased 1-2 orders of magnitude, remained at 10-7 ~ 10-7.5mA/cm 2 sup> between. While the bipolar plate flow field structure is also done some research, is presented for the integrated use of regenerative fuel cell bipolar plate flow field, the flow field for the fuel cell mode (discharge mode) and water electrolysis mode (charging mode ) fluid flow characteristics of each proposed non-uniform fluid flow channel design, the fluid flows through the exchange to achieve conversion between double-effect model, so as to achieve the fuel cell mode and the high efficiency of water electrolysis mode; also presents a field of fuel cell technology stamping sheet metal fuel cell bipolar plate, which consists of three plates, two lateral gas flow field plate as an anode and cathode, respectively, flow field plate, the intermediate plate as a cooling liquid plate. Two electrode plates have the same serpentine flow field, which through four weeks and intermediate flow contact surface contact surface and the intermediate plate is connected to one side of the cooling fluid flow field plate stamping flow channel through the cathode flow field plate on the back of together form the coolant flow channel groove, while the grooves on both sides of the border to prevent the sealing material placed at the coolant drain. Through the thickness of 0.2mm SS304L stainless steel stamping bipolar plate assembly for single cell experiments using Fluent software testing and additional modules for single cell PEMFC performance comparison between the simulation, the simulation results correction model closer to experimental results in order to determine a reliable simulation model. Based on silver - gold composite coating results, modified the model to analyze the different fuel cell contact resistance at room temperature, air humidity on cell performance and to optimize the distribution of the gas flow channel design.