Nickel-iron battery system safety

Eagle-Picher Industries conducted a literature search and experimental tests to characterize the generated flow rates of gaseous hydrogen (GH2) and gaseous oxygen (GO2) from an electrical vehicle (EV) nickel iron battery system. The resulting gassing rates were used to experimentally evaluate the flame quenching capabilities of several candidate devices to prevent the propagation of flame within batteries having central watering/venting systems. The battery generated hydrogen (GH2) and oxygen (GO2) gasses were measured for a complete charge and discharge cycle. The data correlates well with accepted theory during strong overcharge conditions indicating that the measurements are valid for other portions of the cycle. Tests have confirmed that the gas mixture in the cells is always flammable regardless of the battery status. Research of flame arrestor literature yielded little information regarding their operation with hydrogen-oxygen mixtures. It was indicated that a conventional flame arrestor would not be effective over the broad spectrum of gassing conditions presented by a nickel iron battery.