The heat generation rate of nickel-metal hydride battery during charging/discharging

The heat generation rate of nickel-metal hydride battery is investigated during charging/discharging in this study. The heat capacity of 8 Ah cylindrical Ni-MH battery is measured using a large-scale calorimeter. An accelerating rate calorimeter is employed to provide an adiabatic environment for the battery. The generation rates of reaction heat, polarization heat, and combination heat are calculated through curve fitting. Results show that there exits a linear relationship between each generation rate of the three heat items and the charging/discharging currents. It is suggested that the ohm internal resistance of the battery needs to be as low as possible for reducing the ohm heat. In addition, it is better to avoid overcharging in the higher rate of 5 C for battery safety.