Optimization of Energy Storage System Considering Battery Degradation

Energy storage system(ESS) is operated to save and release electric energy. And the battery in an ESS performs an essential function. For this purpose its capacity needs to be finely optimized for specific applications(peak shaving, frequency control, arbitrage, UPS etc).

Some papers have already showed the studies about the topic of optimization of battery capacity in an ESS, but a battery degradation factor and irregular operation event have not much been considered. Actually, ESS may experience a very irregular operational event and the decrease of battery capacity during repeated charge/discharge is a major issue to be addressed. In the ESS industry, usually several factors such as state of charge, time, temperature, and C-rate interdependently affect the decrease of battery capacity in a complicated mode. In order to install the ESS in a specific application looking for a reasonable benefit and a sufficent realiability, ESS lifetime prediction technique considering degradation of battery is highly required.

In this study, the battery capacity fading through test of dynamic stress factors was quantifized and reflected to designing of ESS battery. The goal is to make an accurate estimating methodology of ESS lifetime and benefit from its installation in specific applications.