ELECTRICALLY RESISTIVE COOLANTS FOR PEM FUEL CELLS

摘要

Polymer Electrolyte Membrane (PEM) type fuel cells are typically used at temperatures between 60℃ and 80℃. A coolant is employed to remove excess heat from the fuel cell stack in order to maintain a stable temperature. Both aqueous and non-aqueous based fluids can be used as coolants. This research focuses on aqueous based coolants that can be made and maintained electrically resistive. Different aqueous fluids were studied in scenarios including glass jars and a dynamic test loop system. In glass jar tests, the electrical conductivity (inverse of electrical resistivity) of the fluids was measured at different time intervals, whereas the dynamic test loop utilized in-line monitoring and was capable of generating continuous data. The effects of temperature, presence of different metals (brass, stainless steel, and aluminum), and concentration of key ingredients on the electrical resistivity of the fluids were studied. With proper selection of additives, some coolant formulations could be maintained in excess of 3.3 MegaOhm.cm continuously for a period of more than 30 days.