The impact of monoblock design and battery packaging on the temperature distribution and excursion of the nickel/iron EV batteries was examined by using a generic battery thermal model. It was found that substantial differences in temperature rise and temperature distribution exist between a single cell and a close-pack 5-cell monoblock. During a three-hour constant current discharge, the temperature of the monoblock exceeds the temperature limit set by the battery developer. This problem may be alleviated by providing inter-cell air spaces and applying forced air cooling to the battery. The importance of maintaining uniform air flow distribution in a full-scale nickel/iron battery pack was also illustrated using an example.