Development of Simultaneous Measurement of Water Vapor Adsorption and Proton Conductivity to PEM for PEFC

A new system “MSB-AD-V-FC (BEL JAPAN Inc.)” has been developed, which has made it possible to simultaneous measurement of a water vapor adsorption and a proton conductivity to PEM under various experimental conditions (Temp; 353-473K, Humidity;0-95%RH, Press; atmospheric pressure-1.0MPa). The upper mix-conditioned run to PEM enables in a single original chamber considering of both principles of a gravimetric method for the water vapor adsorption and an alternating current impedance method for proton conductivity and automatically proceeds by software, BEL FCE. Both investigations for the Nafion 112, 1135 and 1035 was achieved under the several experimental conditions. In the case of a run, Nafion 112, 353K, 90%RH and 200kPa, the adsorbed amount for the water vapor and the conductivity (1kHz) was 0.137 (g/g) and 0.117 (S/cm), respectively. Introduction Polymer electrolyte fuel cell (PEFC) invented by GE Co. Ltd. in the latter of 1950’s has been taking advantage of the motor vehicles and the electric power supply for civilian applications because of low operation temperature and compact size. Thereby, the demand for the PEFC will be higher and higher year by year from their point of views. The points of a membrane development are particularly to have heat resisting properties, water holding properties and high proton conductivities under the low humidity condition because it is very important for the high functional membrane in the PEFC to have a low cost and long lifetime under the various environments. When investigating these properties for the membranes, each data for them have been gotten by the each instruments and examined them by the researcher in spite of taking too much time. For the achievement of higher efficiencies to the polymer development, we have developed simultaneous measurements between water vapor adsorption and proton conductivity to the polymer electrolyte membrane (PEM) under the various sets of experimental parameters. Experiment Experimental Apparatus The process flow and the external diagram for a new system “MSB-AD-V-FC” is shown in Figure 1 and Figure 2, respectively. The total apparatus (W2500xH1500xD1000) consists of 3 parts of an experimental parameter control part, a simultaneous sample measurement part and a system control part with data logging as shown in figure 2. The inactive (inert) gas, in this case of N2, and water were mixed into the evaporator and vaporized at high temperature. The water vapor got into a bottom of sample cell (Figure 4) equipped with a sample holder for magnetic suspension balance shown in Figure 3 and an electrode cell for impedance measurements. The temperature in the cell was controlled by an oil circulation pump and the stabilization was ±0.1°C and around the all of tubing, valves and several instruments form the evaporator to the condenser were controlled not to occur water condensation in the system by the air circulating bath or heater flexible horses. The two membranes were fixed onto the both the holder and the cell and able to pretreatment at vacuum or gas flow condition before the measurement. When passing through the cell, the gas under the high or low temperature and humidity was supplied into the condenser to remove the part of water and the pressure of the gas was easily controlled by an automatic back-pressure regulation system. The various sets of parameters of temperature (353-473K), pressure (0.1-1.0Mpa), humidity (0-95%RH) and frequency of an Impedance analyzer etc. were automatically changed by the system control part with an original software BEL-FCE. It was the parameters control, data logging as well as equiribulium judgment of water vapor adsorption and proton Circulator (low temp) Circulator (high temp) VENT Condensed water M2 Water in Water out