Abstract
A polymer composite bipolar plate for polymer electrolyte fuel cell has been prepared by bulk molding compound(BMC) process . The composite bipolar plate is composed of vinyl ester resin and conductive carbon compound . The conductive carbon compound includes graphite 、 carbon fiber and carbon black . Characterization of composite bipolar plate when conducitve carbon compound changes and graphite powder size changes . Universal Testing Machine was used to investigate the flexural strength and the flexural moduluds of composite bipolar plate. Impact Testing Machine was used to investigate the impact strength of composite bipolar plate . Gas permeability analyzer was used to investigate the oxygen permeability of composite bipolar plate . Thermal conductivity detector was used to investigate the thermal conductivity of composite bipolar plate . Potentialstat was used to investigate the corrosion currental of composite bipolar plate . The Horizontal Vertical Flame chamber and limit oxygen index chamber was used to investigate the flame retardance property of composite bipolar plateTGA was used to analyse the thermal property of composite bipolar plate, it shows the thermal stability is 250℃ . Density of composite bipolar plate was from 1.45 to 1.82 . Porosity of composite bipolar plate was from 0.06% to 15.45% . OM microphotogrpaph was ued to investigate the morphology of composite bipolar plate. The hole number in composite bipolar plate was the smallest when graphite content.keeps at 75wt% . Oxygen permeability of composite bipolar plate was from 3.28×10-5(cm3/cm2-sec) to 6.78×10-8(cm3/cm2-sec) . The flexural strength of composite bipolar plate was from 15.96MPa to 57.25MPa . The flexural modulus was from 4585MPa to 20756MPa. The notched Izod impact strength was from 0.18(lb/ft-in) to 0.72 (lb/ft-in) . The unnotched Izod impact strength was from 0.29 (lb/ft-in) to 1.13 (lb/ft-in) . The electrical conductivity was from 0.004(S/cm) to 128(S/cm) . The thermal expansion of composite bipolar plate was from 8.89 (μm/m℃) to 37.33 (μm/m℃) . The linear shrinkage of composite bipolar plate was from 0.05% to 0.98% . The thermal conductivity of composite bipolar plate was from 26.57(W/m-K) to 50.18 (W/m-K) . The composite bipolar plate shows excellent flame retardance and corrosion resistance. The composite bipolar plate meets UL-94VO and LOI>50. The corrosion current was smaller than 10-7(Amps/cm2) .The BMC material was successfully prepard the composite bipolar plate . The flow field path in composite bipolar was 0.9mm and the flow field path distance was 1mm . The thickness of composite bipolar was 3cm.