Improvement of electrical modeling of NiMH battery for application of Microgrid System

Simulation can be a powerful tool to evaluate the batteries for the utilization in system level. It can be a low-cost and simple evaluation method instead of the high-cost and complicate prototyping. However, to guarantee the simulation results of batteries is similar to real condition, it is necessary to get a high-accuracy electrical battery model. In this paper, battery modeling is focused on high capacity of NiMH battery for the application of Microgrid System. The tested battery is prismatic single cell module, 1.2V, 100Ah. Experiment results are shown: The SOC-OCV relation has very strong hysteresis characteristic and its relation in charging and discharging is obviously different. The terminal voltage response has a different order of exponential function between loaded and rest conditions. This paper proposes the different RC networks for loaded and rest condition. The model is developed in PSiM and is verified with the experimental data.