Cycle life prediction is an essential component in the health management of nickel hydrogen battery. Before cell fail, the electrical behavior EODV could reduce with the use. This paper presents a multi-phase EODV degradation model through aging mechanism study and experimental data analysis to evaluate the extent of deterioration of the battery at a specified future time. The model incorporates parameter transformation and accelerated extrapolation for different stress testing. By using such a model, the EODV of the Ni-H-2 cell over time for varied stress aging conditions can be accurately described. The model and inference methods are illustrated with a case application involving charge-discharge test of 15 N-H-2 cells in accelerated condition. The test results are as expected. (C) 2015 The Electrochemical Society. All rights reserved.