Analysis of Second-Life of a Lithium-Ion Battery in an Energy Storage System Connected to a Wind Turbine

At present, the lithium-ion battery (LIB) is one of the most popular electrical energy storage technology for different applications such as electric and hybrid vehicles and aircraft. When the battery is retired in most of these applications, it is still suitable to be used for other applications such as stationary wind and solar energy storage prior to recycling. In this paper, the capacity-fade and the useful remaining life of LIBs that are retired from aircraft or vehicle are studied for the application of wind turbine (WT) power generation. The advantage of these LIBs is the very low added cost when applied for a second-use application. In this study, first, a battery energy storage system is designed for a WT and the duty cycle of a retired LIB cell for the second-life usage in this application is obtained. Then, an empirical model is used to estimate the battery degradation rate and its remaining useful second-life. It is assumed that the LIB is degraded to 85% of the nominal capacity in the first-life and it is degraded to 50% by the end of its second-life application. The results show that the investigated LIB will have almost 7 years useful second-life for the WT application. Less than 0.1% of the generated energy by the WTs is also converted to heat in the battery during charge and discharge processes.