Study on the Improvement of Molding Conditions on the Conductivity Properties of Injection Molded Polar Plate for PEMFC

• Main Authors: Ming-Yi Shih, 施銘奕
• Other Authors: Shia-Chun Chen
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/56854529842195279550

碩士 === 中原大學 === 機械工程研究所 === 93 === Abstract Fuel cell technology is an important energy source for the 21st century. Among fuel cell components, the polar plates are critical. Plastics have been chosen as a candidate material. However, to achieve the polar requirements, the conductivity is key. We investigate the complex behavior of polymer polyphenylene sulfide (PPS) containing 50% carbon fiber in injection molding. Specifically we explore the effects of the injection molding parameters upon the conductivity, measured by the four point probe. The carbon fiber dispersion and orientation seen by scanning electron microscopy (SEM) governs the electrical conductivity. We then used 3D-CAE to simulate the fiber dispersion and orientation under different molding parameters. These simulations closely matched our SEM. We find that under high mold temperature, high melt temperature, or abated injection rate, the carbon fiber distributed uniformly and banded together, increasing conductivity; high packing pressure closely interlaced the carbon fiber, also raising conductivity. Thus, by compacting carbon fiber through the thickness, injection compression molding enhances conductivity by 10%. Keywords : Bipolar plate; PEM fuel cell; injection molding; fiber orientation; carbon fiber; composite conductivity.