Low-Cost Manufacturing of Sheet Molding Compound Bipolar Plates for PEM Fuel Cells

In fuel cell systems, the bipolar plate is known to significantly impact the performance, durability, volume-to-weight ratio, and cost. This project will develop an innovative class of low-cost sheet molding compound (SMC) bipolar plates consisting of a thin nanocomposite core layer sandwiched between two sheets of flexible graphite (FG). The nanocomposite core layer imparts desired structural integrity to the plate while the FG sheets contribute to electrical conductivity, flexibility, resistance to corrosion, and gas permeation. Both the nanocomposite core and the FG sheets each can be very thin (less than 0.125 mm), resulting in ultra-thin bipolar plates and hence fuel cell systems that are more compact and lightweight. Phase I demonstrated that thin FG-SMC bipolar plates can possess conductivity much higher than 100 S/cm (a DOE target), with area specific conductivity greater than 400 S/cm2 (exceeding another DOE target of 100 S/cm2). Phase I also demonstrated the feasibility of an SMC fabrication process. In Phase II, a performance characterization and analysis of the FG-SMC bipolar plates will be conducted to establish product specifications (e.g., the strength, flexibility, electrical conductivity, gas permeation, and corrosion rates of the bipolar plates will be experimentally measured and compared with theoretical predictions), and a pilot-scale apparatus will be constructed. Commercial Applications and Other Benefits as described by the awardee: The automobile fuel cell bipolar plate market size is expected to be approximately $0.74 billion per year by 2011. The market size for motorcycles, other specialty vehicles, and portable device sectors is $0.092 billion, $0.050 billion, and 0.039 billion, respectively. The total worldwide bipolar market size will be $0.921 billion by 2011. Additional potential applications of conductive SMC include electromagnetic interference (EMI) shielding, thermal management (heat dissipation) for microelectronic devices, and battery electrode materials.