Generalized Peukert Equation for Estimating the Remaining Capacity of Nickel–Metal Hydride Batteries

This study aimed to improve the Peukert equation so that it can be used for the nickel–metal hydride batteries at any temperature and discharge current. Batteries of various electrochemical systems are used in many technical devices, vehicles and airplanes. For the operation of any technical object containing batteries, it is very important to know the residual capacity of the batteries because the operation du-ration of the whole technical object depends on the residual capacity of the batteries. In this paper, it is experimentally proven that the generalized Peukert equation C(i,T) = Cm(T)/(1 + (i/i0(T))n(T)) is applicable to nickel–metal hydride batteries at any discharge currents, while the classical Peukert equation can be used only in a limited range of the discharge currents (approximately from 0.3 Cn to 3 Cn). In addition, the classical Peikert equation does not take into account the influence of the temperature of a battery on its released capacity. It is also proven that for the nickel–metal hydride batteries, the generalized Peukert equation heavily depends on battery temperature (via the parameters Cm(T), i0(T) and n(T)).The physical significance of the generalised Peukert equation's parameters' temperature dependencies is also established. Any discharge current and battery temperature can be used with the obtained generalised Peukert equation, which takes the batteries' temperature into account. For standby power of communication systems in photovoltaic systems, electric vehicles, etc., nickel-metal hydride batteries are frequently used. Because they are thought to be more environmentally friendly than nickel-cadmium batteries, nickel-metal hydride batteries require accurate calculation models. Many battery models employ the Peukert equation.