Development of the cycling life model of Ni-MH power batteries for hybrid electric vehicles based on real-world operating conditions

•The first cycling life study of Ni-MH battery pack through 12,000 cycles of real-world battery operating condition test.•A semi-empirical life time aging model has been developed for the Ni-MH battery pack.•DOD is the most important factors affecting the cycle life of the Ni-MH battery in HEV conditions.•The Ah-throughout is found to have little effect on aging process of the Ni-MH battery pack.