Characterization of the performance of commercial Ni/MH batteries

An experimental study is presented for the characterization of commercially available Ni/MH batteries. An experimental study of AA-size cells from Matsushita, Sanyo, and Toshiba was performed to determine the charge and discharge behavior at different rates. The self-discharge characteristics, the cycle-life characteristics, and the effect of temperature on the charge and discharge characteristics are also reported at various rates. Apart from the performance study, a couple of cells from each manufacturer were disassembled to gain insight into the design of the cell and to characterize the separator. The characterization results show that although the three cells were identical in nominal capacity, weight and size, their performance greatly differed in terms of charge and discharge behavior, high rate discharge capabilities, self-discharge losses, charging efficiency, and cycle life.