Characteristics of a hydrogen-absorbing alloy developed for a portable fuel cell

We have been developing a 250 W class portable fuel cell system with a hydrogen supplier utilizing a hydrogen-absorbing alloy to meet demand for a clean and silent power source. A Mm-Y-Ni-Mn alloy with the CaCu5 structure was developed for the hydrogen supplier and characterized with regard to the amount of the effective hydrogen, X(eff) under operating conditions of the fuel cell. X(eff) values between two arbitrary temperature and pressure conditions were evaluated from parameters of a P-C isotherms model. The operating performance of the fuel cell unit was examined and the hydrogen supplier using this alloy was characterized. The hydrogen supplier and the fuel cell unit showed a successful operating performance, The calculated X(eff) value under the operating conditions of the fuel cell well agreed with its actual operation result. It is concluded that the method of evaluating X(eff) by using the P-C isotherms model could contribute to designing the fuel cell system.