Micro-macroscopic coupled modeling of batteries and fuel cells: II. Application to nickel-cadmium and nickel-metal hydride cells

The micro-macroscopic coupled model developed in a companion paper is applied to predict the discharge and charge behaviors of nickel-cadmium (Ni-Cd) and nickel-metal hydride (Ni-MH) cells. The model integrates important microscopic phenomena such as proton or hydrogen diffusion and conduction of electrons in active materials into the macroscopic calculations of species and charge transfer. Simulation results for a full Ni-Cd cell and single MH electrode are presented and validated against the pseudo two-dimensional numerical model in the literature. In good agreement with the previous results, the present family of models is computationally more efficient and is particularly suitable for simulations of complex test conditions, such as the dynamic stress test and pulse charging for electric vehicles. In addition, a mathematical model for full Ni-MH cells is presented and sample simulations are performed for discharge and recharge with oxygen generation and recombination taken into account. These gas reactions represent an important mechanism for battery overcharge in the electric vehicle application.