Abstract
A polymer composite bipolar plate for polymer electrolyte fuel cell has been prepared successfully by bulk molding compound (BMC) process. The composite bipolar plate is composed of vinyl ester resin, conductive carbon compound and nano clay. The conductive carbon compound includes graphite. Organoclay was prepared by ionic exchange of montmorillonite (MMT) with poly(oxypropylene)-backboned amines. The nano clay includes Montmorillonite、Diamine230/Montmorillonite、Diamine400/Montmorillonite、DiamineD2000/Montmorillonite. Characterization of composite bipolar plate was conducted with various nanoclay contents. The flexural strength and the impact strength of composite bipolar plate were tested. The gas permeability and the corrosion current of composite bipolar plate were investigated. The thermal expansion coefficient and the linear shrinkage of composite bipolar p1ate were measured. The flame retardance property of composite bipolar p1ate was also studied. Both the flow field path and depth in composite bipolar plate was 1 mm and the flow field land were 1 mm. The thickness of composite bipolar was 1.5 mm. TGA was used to analyze the thermal property of composite bipolar plate, it shows the thermal stability is 250 oC. Density of composite bipolar plate was increased from 1.71 gcm-3 to 1.86 gcm-3. Porosity of composite bipolar plate was decreased from 1.71 % to 0.25 %. The flexural strength of composite bipolar plate was increased from 31.50 MPa to 50.11 MPa. The unnotched Izod impact strength was increased from 58.21 J/m to 87.10 J/m. The electrical conductivity was increased from 260 S/cm to 306 S/cm . The gas permeability was decreased from 8.13 10-7 cm3cm-2sec-1 to 2.54 10-8 cm3cm-2sec-1. The corrosion current was decreased from 8.4 10-7 Acm-2 to 4.6 10-8 Acm-2. The thermal expansion coefficient was increased from 16.69 μm/moC to 41.24 μ m/moC. The linear shrinkage was increased from 0.07 % to 0.18 %. The thermal conductivity was increased from 13.94 W/m-K to 18.06 W/m-K. The composite bipolar plate meets UL-94V0 and LOI>50. The I-V and I-P curves of single cell reach to 0.65 A/cm2 and 0.16 W/cm2, respectively.