| Fuel Cell is a type of isothermal electrochemical unit that translates the chemical energy that stored in fuel and oxidizer into electric energy. Free from the thermodynamic heat engine cyclic, with high efficiency of energy exchange and environment-friendly, which makes it the most competitive successor to traditional energy source. Since the early60s of the20th century, there have been constant reinvention in the field of fuel cell related technology, and mostly gained advances in recent years. PEMFC has the advantages of pollution-free, corrosion-free and low working temperature, which have made it one of the most widely used form of fuel cell among the6current main stream type, and its development and application have received heavy attentions from counties around the world. At current stage, the main roadblock for mass production of PEMFC is its high cost of manufacturing. Bipolar plate is a key component that consists PEMFC and takes30-45%of the overall cost of production. Resin/graphite composite for bipolar plate has become one of the most heated research focus in this filed due to its high production efficiency, low cost and good anti-corrosion ability,.Epoxy is the most widely used resin adhesive and has various related curing agents. Polyamide650and HHPA are the most common curing agents for firming the cured epoxy. In this work, resin/graphite composites are prepared by mixing the E-44epoxy and two curing agents mentioned above with graphite by hot-pressure molding. This technology applies liquid epoxy and hot-pressure molding simultaneously to complete the molding of resin/graphite composite. In addition, two respective manufacture technical schemes are designed according to the characteristics of each curing agent.We test the resin/graphite composite samples with different percentage of mixture by three-point bending fracture tests, including the mechanical property analysis, TG analysis for the stability under the working condition and.SEM analysis for the microstructures. For mechanical property, the results show that with the increase of resin and the reduction of graphite, the composite has a increasing bending load, bending strength and stiffness. TG analysis results indicate that the heat resistances of two tested composites have both met the working temperature requirements for fuel cell. SEM analysis of the three-point bending fracture surface shows that, the samples using HHPA cured are slightly better than that using polyamide650.It comes to the conclusions that, comparing the two production technologies, the use of anhydride-type curing agents mixed with epoxy has a longer curing time under the good temperature liquidity, which provides more operating time and shows a better mixed effect. In addition under low temperature, anhydride-type curing agents could be better stored for long term, the roughness of the sample surface is better than that curing by polyamide650and has less porosity after pressure molding. |
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