An Age-Dependent Battery Energy Storage Degradation Model for Power System Operations

Power system operations need to consider the degradation characteristics of battery energy storage (BES) in the modeling and optimization. Existing methods commonly bridge the mapping from charging and/or discharging behaviors to the BES degradation cost with fixed parameters. However, BES degradation characteristics constantly change during the aging process, so the fixed-parameter models cannot be precise throughout the lifespan. This letter introduces an age-dependent BES degradation model that captures the changes in characteristics. Based on the Arrhenius battery degradation equation, we deduce an analytical expression of the degradation that uses the operation variables of BES in the power system perspective as inputs. Then, we convexify the expression to enable the embedding of age-dependent degradation characteristics into power system optimization models. The corresponding interaction framework between the proposed degradation model and power system optimization models is also established. Case studies show the proposed model can limit the error within three percent in the lifespan.